Exposure apparatus, exposure method, and method for producing device

This application claims the benefit of priority of U.S. Provisional Application No. 61/136,725 filed on Sep. 29, 2008, the entire disclosures of which are incorporated herein by reference.

1. Field of the Invention

The present invention relates to a scanning type exposure apparatus which transfers a pattern of a mask to a photosensitive substrate, an exposure method, and a method for producing a device.

2. Description of the Related Art

In the photolithography step for producing, for example, a semiconductor device or element, an exposure apparatus is used, wherein a pattern of an image (pattern image) of a mask (or a reticle) is projected onto a photosensitive substrate (for example, a wafer coated with a photoresist) via a projection optical system to perform the exposure. In the ordinary exposure apparatus, one pattern is formed on one shot area on the photosensitive substrate. On the other hand, in order to improve the throughput, an exposure apparatus of the double exposure system has been suggested, wherein a same shot area on a photosensitive substrate is subjected to the scanning exposure with two patterns by using a so-called two-headed type projection optical system (see, for example, Japanese Patent Application Laid-open No. 2007-201457).

In recent years, it has been investigated to large-size the photosensitive substrate to be used for the photolithography step. However, in the conventional technique as described above, when the number of shot areas provided on the photosensitive substrate is increased as the photosensitive substrate is large-sized, the throughput of the photolithography step is lowered approximately in proportion to the ratio of the increase.

An object of aspects of the present invention is to provide an exposure apparatus, an exposure method, and a method for producing a device which make it possible to achieve the improvement in the throughput in relation to the scanning exposure.

According to a first aspect of the prevent invention, there is provided an exposure apparatus comprising: a mask-moving section which holds a mask formed with a pattern and which is movable in a first direction; an illumination system which irradiates an exposure light onto the mask held by the mask-moving section and which forms a first illumination area and a second illumination area separated from each other by a spacing distance in the first direction; a substrate-moving section which holds a photosensitive substrate and which is movable in a second direction corresponding to the first direction and in synchronization with the mask-moving section; a projection optical system which forms a first projected image of the pattern positioned in the first illumination area and a second projected image of the pattern positioned in the second illumination area, on the photosensitive substrate held by the substrate-moving section; and a restricting section which restricts the first projected image and the second projected image on the photosensitive substrate to be within a first projection area and a second projection area respectively; wherein an area-to-area spacing distance, in the first direction, between a first conjugate area optically conjugate with the first projection area via the projection optical system and a second conjugate area optically conjugate with the second projection area via the projection optical system is set to be such a spacing distance that scanning exposures with the pattern with respect to a first transfer area and a second transfer area provided adjacently in the second direction on the photosensitive substrate are successively performed corresponding to synchronous movement of the mask-moving section and the substrate-moving section.

According to a second aspect of the present invention, there is provided an exposure apparatus which exposes a substrate with an image of a pattern formed on a mask, the exposure apparatus comprising: an illumination system which forms a first illumination area and a second illumination area, with a spacing distance, on a plane same as the mask; a mask-moving section which is movable continuously while holding the make to make the pattern pass successively through the first illumination area and the second illumination area; a projection system which projects a first image and a second image on the substrate, the first image and the second image being formed when the pattern passes through the first illumination area and the second illumination area, respectively; and a substrate-moving section which is movable continuously, while holding the substrate, in a direction corresponding to movement of the mask-moving section and in synchronization with the movement of the mask-moving section to successively form the first image and the second image in different areas, respectively, on the substrate.

According to a third aspect of the present invention, there is provided an exposure method comprising: irradiating an exposure light onto a mask formed with a pattern to form a first illumination area and a second illumination area which are separated from each other by a spacing distance in a first direction; forming, on a photosensitive substrate, a first projected image of the pattern positioned in the first illumination area and a second projected image of the pattern positioned in the second illumination area; and synchronously moving the mask and the photosensitive substrate in the first direction and a second direction corresponding to the first direction respectively to successively perform scanning exposure operations with the pattern with respect to a first transfer area and a second transfer area which are provided adjacently in the second direction on the photosensitive substrate.

According to a fourth aspect of the present invention, there is provided an exposure method for exposing a substrate with an image of a pattern formed on a mask, the exposure method comprising: forming a first illumination area and a second illumination area, with a spacing distance, on a plane same as the mask; moving the mask continuously relative to the first illumination area and the second illumination area to make the pattern pass successively through the first illumination area and the second illumination area; projecting a first image and a second image on the substrate, the first image and the second image being formed when the pattern passes through the first illumination area and the second illumination area, respectively; and moving the substrate continuously in a direction corresponding to movement of the mask and in synchronization with the movement of the mask to successively form the first image and the second image in different areas, respectively, on the substrate.

According to a fifth aspect of the present invention, there is provided a method for producing a device, comprising: using the exposure apparatus according to the first or second aspect of the present invention or the exposure method according to the third or fourth aspect of the present invention to transfer the pattern of the mask to the photosensitive substrate; and processing the photosensitive substrate, to which the pattern has been transferred, based on the pattern.

According to the aspects of the present invention, it is possible to achieve the improvement in the throughput in relation to the scanning exposure.

FIG. 1 shows a construction of an exposure apparatus according to a first embodiment of the present invention.

FIG. 2 shows a pair of illumination areas formed on an object plane of a projection optical system.

FIG. 3 shows a pair of projection areas formed on a wafer.

FIG. 4 shows positional relationships between the illumination areas and a pattern area at a start time point and an end time point of the scanning exposure for a first shot area in the first embodiment.

FIG. 5 shows positional relationships between the projection areas and shot areas at the start time point and the end time point of the scanning exposure for the first shot area in the first embodiment.

FIG. 6 shows positional relationships between the illumination areas and the pattern area at a start time point and an end time point of the scanning exposure for the second shot area in the first embodiment.

FIG. 7 shows positional relationships between the projection areas and the shot areas at the start time point and the end time point of the scanning exposure for the second shot area in the first embodiment.

FIG. 8 is a first drawing illustrating a condition required to continuously perform the scanning exposure for two adjacent shot areas in the first embodiment.

FIG. 9 is a second drawing illustrating the condition required to continuously perform the scanning exposure for the two adjacent shot areas in the first embodiment.

FIG. 10 illustrates a scanning procedure in the first embodiment.

FIG. 11 illustrates a scanning procedure in a conventional technique.

FIG. 12 shows a construction of an exposure apparatus according to a modification of the first embodiment.

FIG. 13 shows a construction of an exposure apparatus according to a second embodiment of the present invention.

FIG. 14 shows positional relationships between illumination areas and a pattern area at a start time point and an end time point of the scanning exposure for a first shot area in the second embodiment.

FIG. 15 shows positional relationships between projection areas and shot areas at the start time point and the end time point of the scanning exposure for the first shot area in the second embodiment.

FIG. 16 shows positional relationships between the illumination areas and the pattern area at a start time point and an end time point of the scanning exposure for the second shot area in the second embodiment.

FIG. 17 shows positional relationships between the projection areas and the shot areas at the start time point and the end time point of the scanning exposure for the second shot area in the second embodiment.

FIG. 18 is a first drawing illustrating a condition required to continuously perform the scanning exposure for two adjacent shot areas in the second embodiment.

FIG. 19 is a second drawing illustrating the condition required to continuously perform the scanning exposure for the two adjacent shot areas in the second embodiment.

FIG. 20 shows a construction of an exposure apparatus according to a modification of the second embodiment.

FIG. 21 shows an example of a catadioptric optical system applicable to the second embodiment, wherein all transmissive optical members are coaxially arranged.

FIG. 22 shows another example of a catadioptric optical system applicable to the second embodiment, wherein all transmissive optical members are coaxially arranged.

FIG. 23 is a flow chart illustrating the outline of an exposure method of the present invention.

FIG. 24 is a flow chart illustrating steps of producing a semiconductor device.

FIG. 25 is a flow chart illustrating steps of producing a liquid crystal device.

An embodiment of the present invention will be explained based on the attached drawings. FIG. 1 shows the construction of an exposure apparatus according to a first embodiment of the present invention. In FIG. 1 , the Z axis is defined in a direction of a reference optical axis AX of a projection optical system PL, the X axis is defined in parallel to the sheet surface of FIG. 1 in a plane perpendicular to the optical axis AX, and the Y axis is defined perpendicularly to the sheet surface of FIG. 1 in the plane perpendicular to the optical axis AX.

The exposure apparatus EX of the first embodiment includes a pair of illumination systems IL 1 , IL 2 which illuminate a mask M formed with a predetermined pattern with an exposure light (illumination light) radiated from a light source or light sources (not shown). The pair of illumination systems IL 1 , IL 2 are mutually constructed in the same manner, and are provided symmetrically in relation to the YZ plane including the reference optical axis AX of the projection optical system PL. The second illumination system IL 2 is arranged while being separated by a spacing distance on the side in the +X direction from the first illumination system IL 1 . Each of the illumination systems IL 1 , IL 2 includes an individual light source or a common light source is provided for the illumination systems IL 1 , IL 2 ; and each of the illumination systems IL 1 and IL 2 is constructed of an optical integrator, a field diaphragm, a condenser lens, etc. As the light source, it is possible to use, for example, the ArF excimer laser. Instead of the ArF excimer laser, it is also allowable to use another light source, for example, a high harmonic wave-generating device which includes, for example, a solid laser light source such as a DFB semiconductor laser or a fiber laser; a light-amplifying section having a fiber amplifier or the like; and a wavelength-converting section, and which outputs a pulse light beam having a wavelength of 193 nm as disclosed, for example, in International Publication No. 1999/46835 (corresponding to U.S. Pat. No. 7,023,610).

The illumination systems IL 1 , IL 2 form illumination areas IR 1 , IR 2 , with exposure lights (illumination lights) EL 1 , EL 2 irradiated from the illumination systems IL 1 , IL 2 respectively, on an object plane PLo of the projection optical system PL (a surface of the mask or a plane same as the surface of the mask) respectively. In a reference state in relation to the scanning exposure, as shown in FIG. 2 , each of the illumination areas IR 1 , IR 2 has a rectangular outer shape which is long in the Y direction, and the illumination areas IR 1 , IR 2 are formed symmetrically in relation to the YZ plane including the reference optical axis AX. The second illumination area IR 2 is formed while being separated, by a spacing distance on the side in the +X direction, from the first illumination area IR 1 . However, the shapes and the sizes of the illumination areas IR 1 , IR 2 during the scanning exposure are defined by mask blinds MB 1 , MB 2 which serve as field diaphragms and are arranged in the illumination systems IL 1 , IL 2 at positions substantially optically conjugate with the object plane PLo.

Each of the mask blinds MB 1 , MB 2 is constructed by using a light-shielding member (movable blind) provided movably in a direction intersecting the optical path for the exposure light (for example, in a direction perpendicular to the optical path); and each of the mask blinds MB 1 , MB 2 moves the light-shielding member to control the area of an opening (light-transmitting portion) defined by the light-shielding member. The operations of the mask blinds MB 1 , MB 2 are controlled by blind-driving systems BD 1 , BD 2 based on instruction from a controller CR. Reference may be made, for example, to Japanese Patent Application Laid-open No. 2007-287760 (corresponding to U.S. Patent Application Publication No. US 2007/0242363) in relation to specific constructions and operations of the mask blinds MB 1 , MB 2 . The contents of U.S. Patent Application Publication No. US 2007/0242363 are incorporated herein by reference within a range of permission of the domestic laws and ordinances.

The mask M is held in parallel to the XY plane on a mask stage MS. The mask M is positioned so that a pattern area PA of the mask M is substantially coincident with the object plane PLo of the projection optical system PL. FIG. 1 shows a state that the mask stage MS is separated from the mask M in order to clarify the drawing. The mask stage MS is two-dimensionally movable along the XY plane in accordance with the action of a mask-driving system MD, based on instruction from the controller CR. The position coordinate of the mask stage MS is measured by a mask interferometer (not shown), and the position of the mask stage MS is controlled by the mask interferometer.

The light EL 1 , which is transmitted through the first illumination area IR 1 and the pattern area PA, passes through the so-called two-headed type projection optical system PL, and the light EL 1 forms a projected image of the pattern in a first projection area ER 1 on a wafer W as a photosensitive substrate (as well as on the image plane of the projection optical system PL). On the other hand, the light EL 2 , which is transmitted through the second illumination area IR 2 and the pattern area PA, passes through the projection optical system PL, and the light EL 2 forms a projected image of the pattern in a second projection area ER 2 on the wafer W.

The projection areas ER 1 , ER 2 are the areas which are optically conjugate with the illumination areas IR 1 , IR 2 . Therefore, as shown in FIG. 3 , the projection areas ER 1 , ER 2 have outer shapes which are long in the Y direction, and are formed symmetrically in relation to the YZ plane including the reference optical axis AX in an image field IF of the projection optical system PL. However, the second projection area ER 2 is formed while being separated, by a spacing distance on the side in the −X direction, from the first projection area ER 1 . The specific construction and the action of the projection optical system PL will be described later on.

The wafer W is held in parallel to the XY plane on the wafer stage WS. The wafer W is positioned so that the surface of the wafer W (transfer surface; photosensitive surface) is substantially coincident with the image plane of the projection optical system PL. The wafer stage WS is two-dimensionally movable along the XY plane in accordance with the action of a wafer-driving system WD based on the instruction supplied from the controller CR. The position coordinate of the wafer stage WS is measured by a wafer interferometer (not shown), and the position of the wafer stage WS is controlled by the wafer interferometer.

The Exposure apparatus EX is provided with a wafer alignment system which detects an alignment mark formed on each shot areas on the wafer W, and a mask alignment system which detects an alignment mark formed on the mask M to thereby position the each shot area on the wafer W on the wafer stage WS and a pattern PA formed on the mask M. Examples of these alignment systems, it is allowable to use alignment systems as disclosed, for example, in Japanese Patent Application Laid-open No. 4-65603 (corresponding to U.S. Pat. No. 5,493,403), U.S. Pat. No. 5,646,413, etc. Here, any explanation on the specific constructions and operations of the alignment systems will be omitted.

In the first embodiment, the mask stage MS and the wafer stage WS are synchronously moved in the X direction at a velocity ratio corresponding to the magnitude (absolute value) β of the projection magnification of the projection optical system PL. Accordingly, the pattern (a first image formed by the pattern) in the pattern area PA, which is illuminated in the first illumination area IR 1 , is transferred to a first shot area (first transfer area) on the wafer W, and the pattern (a second image formed by the pattern) of the pattern area PA, which is illuminated in a second illumination area IR 2 , is transferred to a second shot area (second transfer area) disposed adjacently to the first shot area in the X direction. Details will be described later on about the exposure operation in which the scanning exposure is continuously performed for the two adjoining or adjacent shot areas.

With reference to FIG. 1 again, the projection optical system PL has a first imaging system G 1 which forms a first intermediate image of the pattern illuminated in the first illumination area IR 1 , a second imaging system G 2 which forms a second intermediate image of the pattern illuminated in the second illumination area IR 2 , and a third imaging system G 3 which forms the projected image of the pattern in the first projection area ER 1 based on the first intermediate image and which forms the projected image of the pattern in the second projection area ER 2 based on the second intermediate image. The third imaging system G 3 is a dioptric optical system, and an optical axis AX 3 of the third imaging system G 3 is coincident with the reference optical axis AX of the projection optical system PL.

The first imaging system G 1 and the second imaging system G 2 are mutually constructed in the same manner, and are catadioptric optical systems provided symmetrically in relation to the YZ plane including the optical axis AX 3 of the third imaging system G 3 (as well as the reference optical axis AX). Specifically, the first imaging system G 1 (second imaging system G 2 ) is provided with a field lens L 11 (L 21 ), a flat reflecting mirror FM 1 (FM 2 ), a positive lens group L 12 (L 22 ), and a concave reflecting mirror CM 1 (CM 2 ) as referred to in an order of the incidence of the light. A deflecting member PM, which has reflecting surfaces R 1 , R 2 , is arranged in the optical path between the first and second imaging systems G 1 , G 2 and the third imaging system G 3 .

In the projection optical system PL, the light come from the pattern illuminated in the first illumination area IR 1 passes along the field lens L 11 , the flat reflecting mirror FM 1 , and the positive lens group L 12 , and the light comes into the concave reflecting mirror CM 1 . The light reflected by the concave reflecting mirror CM 1 forms the first intermediate image via the positive lens group L 12 . The first intermediate image is, for example, a substantially 1× magnification image of the mask pattern, and the image is erected in the X direction and inverted in the Y direction. The light from the first intermediate image is reflected by the reflecting surface R 1 of the deflecting member PM, and the light forms a projected image (a first projected image) of the pattern in the first projection area ER 1 on the wafer W via the third imaging system G 3 . The first projected image is, for example, a reduction image of about ¼ of the mask pattern, and the image is inverted in the X direction and erected in the Y direction.

Similarly, the light come from the pattern illuminated in the second illumination area IR 2 , passes along the field lens L 21 , the flat reflecting mirror FM 2 , and the positive lens group L 22 , and the light comes into the concave reflecting mirror CM 2 . The light reflected by the concave reflecting mirror CM 2 forms the second intermediate image via the positive lens group L 22 . The second intermediate image is, for example, a substantially 1× magnification image of the mask pattern, and the image is erected in the X direction and inverted in the Y direction in the same manner as the first intermediate image. The light from the second intermediate image is reflected by the reflecting surface R 2 of the deflecting member PM, and the light forms the projected image of the pattern in the second projection area ER 2 on the wafer W via the third imaging system G 3 . The second projected image is, for example, a reduction image of about ¼ of the mask pattern, and the image is inverted in the X direction and erected in the Y direction in the same manner as the first projected image.

In this way, in the first embodiment, the +X direction (or the −X direction) in the mask stage MS and the −X direction (or the +X direction) in the wafer stage WS optically correspond to one another via the projection optical system PL. Therefore, when the scanning exposure is performed for each of the shot areas, the mask stage MS is moved in the +X direction (or in the −X direction) while holding the mask M formed with the pattern, and the wafer stage WS is moved, in synchronization with the mask stage MS, in the −X direction (or in the +X direction) (i.e., in the direction opposite to that of the mask stage MS) while holding the wafer W.

That is, in the first embodiment, the wafer stage WS is moved in the direction directed from the first projection area ER 1 to the second projection area ER 2 (in the direction of the −X direction) in the X direction in synchronization with the movement in which the mask stage MS is moved in the direction directed from the first illumination area (first conjugate area) IR 1 to the second illumination area (second conjugate area) IR 2 (in the direction of the +X direction) in the X direction. In another situation, the wafer stage WS is moved in the direction of the +X direction in synchronization with the movement in which the mask stage MS is moved in the direction of the −X direction. Note that, before performing the scanning exposure for each of the shot areas, the alignment mark formed in the mask M and the alignment mark formed in the wafer W are detected by the alignment systems to thereby control the position of the mask stage MS and the position the wafer stage WS and to position the pattern area PA of the mask M with respect to the each of the shot areas.

An explanation will be made below with reference to FIGS. 4 to 7 about the exposure operation in which the scanning exposure is continuously performed for two adjacent or adjoining shot areas in the first embodiment. FIGS. 4 to 7 are illustrative of an exemplary case of the scanning exposure in which the mask stage MS is moved in the +X direction and the wafer stage WS is moved in the −X direction by way of example. As depicted by solid lines in FIG. 4 , the scanning exposure is started for a first shot area SR 1 at the point in time at which an edge PAPX on the side in the +X direction of the pattern area PA of the mask M is coincident with an edge IR 1 MX on the side in the −X direction of the first illumination area IR 1 . At the time point of the start of the scanning exposure for the first shot area SR 1 , since the first shot area SR 1 and the pattern PA have been already positioned with respect to each other via the alignment system before the start of the exposure, an edge SR 1 MX on the side in the −X direction of the first shot area SR 1 is coincident with an edge ER 1 PX on the side in the +X direction of the first projection area ER 1 , as depicted by solid lines in FIG. 5 .

Subsequently, as shown by broken lines in FIG. 4 , the scanning exposure for the first shot area SR 1 is completed at the point in time at which an edge PAMX on the side in the −X direction of the pattern area PA is moved to an edge IR 1 PX on the side in the +X direction of the first illumination area IR 1 . At the time point at which the scanning exposure for the first shot area SR 1 is completed, as shown by broken lines in FIG. 5 , an edge SR 1 PX on the side in the +X direction of the first shot area SR 1 is coincident with an edge ER 1 MX on the side in the −X direction of the first projection area ER 1 .

However, when the scanning exposure is performed for the first shot area SR 1 , the second illumination area IR 2 (as well as the second projection area ER 2 ) is not formed in accordance with the action of the mask blind MB 2 included in the second illumination system IL 2 (the blind is closed) so that the first shot area SR 1 is not affected by the second projection area ER 2 . In other words, the illumination systems IL 1 , IL 2 successively form the first illumination area IR 1 (as well as the first projection area ER 1 ) and the second illumination area IR 2 (as well as the second projection area ER 2 ). In this procedure, the mask blinds MB 1 , MB 2 decrease the areas of the openings of the blinds by successively increasing the size in the X direction of the first projection area ER 1 and the size in the X direction of the second projection area ER 2 respectively.

Further, the size of the first illumination area IR 1 in the X direction (as well as the first projection area ER 1 ) is gradually decreased from a predetermined value in the reference state to zero (0) in accordance with the action of the mask blind MB 1 included in the first illumination system IL 1 so that the second shot area SR 2 following the first shot area SR 1 is not affected by the first projection area ER 1 during the scanning exposure for the first shot area SR 1 . Specifically, the size in the X direction of the first illumination area IR 1 (as well as the first projection area ER 1 ) starts to be decreased at the point in time at which the edge SR 1 PX on the side in the +X direction of the first shot area SR 1 goes past the edge ER 1 PX on the side in the +X direction of the first projection area ER 1 , and the size in the X direction of the first illumination area IR 1 (as well as the first projection area ER 1 ) is decreased to zero so that the second shot area SR 2 is not affected by the first projection area ER 1 .

The scanning exposure for the second shot area SR 2 is started at the point in time at which the mask stage MS is further moved in the +X direction, and the edge PAPX on the side in the +X direction of the pattern area PA is coincident with an edge IR 2 MX on the side in the −X direction of the second illumination area IR 2 as depicted by solid lines in FIG. 6 . At the time point at which the scanning exposure is started for the second shot area SR 2 , an edge SR 2 MX on the side in the −X direction of the second shot area SR 2 is coincident with an edge ER 2 PX on the side in the +X direction of the second projection area ER 2 , as depicted by solid lines in FIG. 7 . However, prior to the start of the scanning exposure for the second shot area SR 2 , the size in the X direction of the second illumination area IR 2 (as well as the second projection area ER 2 ) is gradually increased from zero to the predetermined value in the reference state in accordance with the action of the mask blind MB 2 while preventing the first shot area SR 1 from being affected by the second projection area ER 2 .

Subsequently, the scanning exposure for the second shot area SR 2 is completed at the point in time at which the edge PAMX on the side in the −X direction of the pattern area PA is moved to an edge IR 2 PX on the side in the +X direction of the second illumination area IR 2 , as depicted by broken lines in FIG. 6 . At the time point at which the scanning exposure is completed for the second shot area SR 2 , an edge SR 2 PX on the side in the +X direction of the second shot area SR 2 is coincident with an edge ER 2 MX on the side in the −X direction of the second projection area ER 2 , as depicted by broken lines in FIG. 7 .

The size in the X direction of the second illumination area IR 2 (as well as the second projection area ER 2 ) is gradually decreased from the predetermined value in the reference state to zero in accordance with the action of the mask blind MB 2 included in the second illumination system IL 2 so that a third shot area (not shown) following the second shot area SR 2 is not affected by the second projection area ER 2 during or after the completion of the scanning exposure for the second shot area SR 2 . Specifically, the size in the X direction of the second illumination area IR 2 (as well as the second projection area ER 2 ) starts to be decreased at the point in time at which the edge SR 2 PX on the side in the +X direction of the second shot area SR 2 goes past the edge ER 2 PX on the side in the +X direction of the second projection area ER 2 , and the size in the X direction of the second illumination area IR 2 (as well as the second projection area ER 2 ) is decreased to zero so that the third shot area is not affected by the second projection area ER 2 .

In this procedure, the size in the X direction of the first illumination area IR 1 (as well as the first projection area ER 1 ) is gradually decreased from the predetermined value in the reference state to zero by the mask blind MB 1 so that the following second shot area SR 2 is not affected by the first projection area ER 1 during the scanning exposure for the first shot area SR 1 ; and further, the size in the X direction of the second illumination area IR 2 (as well as the second projection area ER 2 ) is gradually increased from zero to the predetermined value in the reference state by the mask blind MB 2 so that the first shot area SR 1 is not affected by the second projection area ER 2 prior to the start of the scanning exposure for the second shot area SR 2 . However, when the spacing distance between the first shot area SR 1 and the second shot area SR 2 is sufficiently wide, it is also allowable that the mask blinds MB 1 , MB 2 remain open respectively.

Next, an explanation will be made with reference to FIGS. 8 and 9 about the condition required to perform the scanning exposure continuously for the two adjacent shot areas SR 1 , SR 2 in the first embodiment. In order to simplify the explanation, FIG. 8 shows a state that the edge PAMX on the side in the −X direction of the pattern area PA arrives at a center IR 1 C of the first illumination area IR 1 . FIG. 9 shows a state that the edge SR 1 PX on the side in the +X direction of the first shot area SR 1 arrives at a center ER 1 C of the first projection area ER 1 corresponding to the positional relationship between the pattern PA and the first illumination area IR 1 shown in FIG. 8 .

With reference to FIG. 8 , reference symbol “U” indicates the center-to-center spacing distance in the X direction between the center IR 1 C of the first illumination area IR 1 and a center IR 2 C of the second illumination area IR 2 . Reference symbol “P” indicates the size in the X direction of the pattern area PA, and reference symbol “D” indicates the size in the X direction of each of the first illumination area IR 1 and the second illumination area IR 2 . Reference symbol “ΔX” indicates the distance in the X direction between the edge PAPX on the side in the +X direction of the pattern area PA and the center IR 2 C of the second illumination area IR 2 in the state shown in FIG. 8 .

With reference to FIG. 9 , reference symbol “S” indicates the size in the X direction of each of the first shot area SR 1 and the second shot area SR 2 , and reference symbol “K” indicates the spacing distance in the X direction between the first shot area SR 1 and the second shot area SR 2 . Reference symbol “V” indicates the center-to-center spacing distance in the X direction between the center ER 1 C of the first projection area ER 1 and a center ER 2 C of the second projection area ER 2 , and reference symbol “T” indicates the spacing distance in the X direction between the first projection area ER 1 and the second projection area ER 2 .

In this case, the relationships hold as shown by the following expressions (1) to (4).

U=P+ΔX   (1)

P=S/β   (2)

ΔX =( V+K )/β  (3)

V=β×D+T   (4)

Here, the expressions (1), (2) and (4) define the relationship derived from the distance in the X direction between the first illumination area IR 1 and the second illumination area IR 2 , the length (width) in the X direction of each of the first illumination area IR 1 and the second illumination area IR 2 , the length in the X direction of the pattern area PA, the distance in the X direction between the first projection area ER 1 and the second projection area ER 2 and the length (width) in the X direction of each of the first projection area ER 1 and the second projection area ER 2 . The expression (3) shows the relationship among the length in the X direction of each of the first shot area SR 1 and the second shot area SR 2 , the length in the X direction of the pattern area PA and the spacing distance in the X direction between the first shot area SR 1 and the second shot area SR 2 with respect to the projection magnification β, etc, and the expression (3) defines the following condition. That is, a situation is assumed in which the pattern PA is further moved, from the position of the pattern PA with respect to the second illumination area IR 2 shown in FIG. 8 , in the scanning direction (+X direction) by the distance ΔX and the edge PAPX on the side in the +X direction of the pattern area PA arrives at the center IR 2 C of the second illumination area IR 2 . In this situation, it is necessary that the transfer of the pattern PA onto the second shot area SR 2 is started. Namely, the edge SR 2 MX on the side in the −X direction of the second shot area SR 2 needs to arrive at the center ER 2 C of the second projection area ER 2 . If not so, the image of the pattern PA is not correctly transferred onto the second shot area SR 2 . Therefore, the second shot area SR 2 needs to be moved by V+K while the pattern PA of the mask is moved by ΔX, and considering the projection magnification β, it is necessary that the relationship of ΔX=(V+K)/β holds. Note that the first shot area SR 1 is positioned with respect to the pattern PA of the mask M by the alignment operation; and with respect to this, it is allowable that the second shot area SR 2 is considered to be aligned, in relation to the first shot area SR 1 , via the relationship of the expression (3).

The following conditional expressions (A), (B), (C) are obtained from the relationships expressed in the expressions (1) to (4). The conditional expressions (A), (B), (C) differ only in the expression forms; and when one conditional expression of the conditional expressions is satisfied, the other two conditional expressions are also satisfied.

U =( S+K+V )/β  (A)

U=P +( K+V )/β  (B)

U=P+D +( T+K )/β  (C)

As described above, the first embodiment is constructed so that the center-to-center spacing distance U in the X direction, which is between the center IR 1 C of the first illumination area IR 1 as the first conjugate area optically conjugate with the first projection area ER 1 via the projection optical system PL and the center IR 2 C of the second illumination area IR 2 as the second conjugate area optically conjugate with the second projection area ER 2 via the projection optical system PL, satisfies the conditional expression (A) as well as the conditional expressions (B), (C). With this, the scanning exposure can be performed continuously for the two shot areas SR 1 , SR 2 which are adjacent to one another in the X direction, by performing the synchronous movement in the X direction of the mask stage MS and the wafer stage WS once (synchronous movement including no step movement in the Y direction).

In the exposure apparatus of the first embodiment, the scanning exposure can be continuously performed for the two adjacent shot areas. Therefore, it is possible to achieve the improvement in the throughput in relation to the scanning exposure, for example, based on the simple scanning procedure as shown in FIG. 10 . FIG. 10 schematically shows the locus of the reference optical axis AX of the projection optical system PL with respect to six shot areas SR 1 to SR 6 by way of example. In FIG. 10 , the solid lines indicate the locus of the reference optical axis AX as brought about in accordance with the synchronous movement of the mask stage MS and the wafer stage WS during the scanning exposure for pairs of the shot areas, and the broken lines indicate the locus of the reference optical axis AX as brought about in accordance with the step movement of the wafer stage WS between the scanning exposure for a pair of the shot areas and the scanning exposure for the next pair of the shot areas. These loci indicate the relative loci of the reference optical axis AX relative to the respective shot areas.

Specifically, in the scanning procedure of the first embodiment shown in FIG. 10 , the scanning exposure is performed for the first pair of the shot areas SR 1 , SR 2 by moving the mask stage MS in the +X direction and moving the wafer stage WS in the −X direction. After that, the movement of the mask stage MS and the wafer stage WS is decelerated in relation to the X direction, and the movement direction is returned to accelerate the movement again, during which the wafer stage WS is step-moved in the +Y direction in order to perform the scanning exposure for the next pair of the shot areas SR 3 , SR 4 . Subsequently, the mask stage MS is moved in the −X direction, and the wafer stage WS is moved in the +X direction to perform the scanning exposure for the second pair of the shot areas SR 3 , SR 4 .

Further, the wafer stage WS is step-moved in the +Y direction in order to perform the scanning exposure for the next pair of the shot areas SR 5 , SR 6 . After that, the mask stage MS is moved in the +X direction, and the wafer stage WS is moved in the −X direction to perform the scanning exposure for the third pair of the shot areas SR 5 , SR 6 . In this way, in the exposure apparatus of the first embodiment, the operation of the scanning exposure for a pair of shot areas and the operation of the step movement to perform the scanning exposure for the next pair of shot areas are alternately repeated. In the exposure apparatus of the present invention, attention should be directed to the point that two shot areas are simultaneously (continuously) exposed by one time of scanning or by one-way scanning (one-scan two-shots exposure). Further, it is enough that the positioning (alignment) of the pattern PA with respect to the two shot areas is performed only for the shot area, among the two shot areas, which is to be exposed first.

On the contrary, as described above, in the case of the conventional scanning exposure technique, only one shot area is exposure by one time of scanning. Therefore, basically, the step-movement is required every time the scanning is performed. Namely, the operation of the scanning exposure for one shot area and the operation of the step movement to perform the scanning exposure for the next shot area are alternately repeated. Therefore, as shown in FIG. 11 , for example, the conventional scanning exposure technique requires a large number of the operations of the step movement; and the scanning procedure is relatively complex, and it is difficult to achieve the high throughput. Further, it is necessary that the positioning (alignment) of the pattern PA with respect to the shot area is performed for each of the shot areas. Also in FIG. 11 , the solid lines indicate the locus of the reference optical axis of the projection optical system brought about during the scanning exposure for the respective shot areas, and the broken lines indicate the locus of the reference optical axis brought about in accordance with the step movement from one shot area to the next shot area in the same manner as in the procedure shown in FIG. 10 .

Specifically, in the case of the scanning procedure of the conventional scanning exposure technique shown in FIG. 11 , the scanning exposure for the shot area SR 1 , the step movement to perform the scanning exposure for the shot area SR 2 , the scanning exposure for the shot area SR 2 , the step movement to perform the scanning exposure for the shot area SR 3 , and the scanning exposure for the shot area SR 3 are successively performed. Subsequently, after the linear step movement to perform the scanning exposure for the shot area SR 4 , the followings are successively performed: the scanning exposure for the shot area SR 4 ; then the step movement to perform the scanning exposure for the shot area SR 5 , and then the scanning exposure for the shot area SR 5 ; and then the step movement to perform the scanning exposure for the shot area SR 6 , and then the scanning exposure for the shot area SR 6 .

As appreciated from the loci of the reference optical axis AX brought about the step-movements as shown in FIGS. 10 and 11 , the scanning exposure method of the present invention has a route, for scanning the shot areas on the substrate (wafer) with the exposure light, which is simpler than that in the conventional scanning exposure method and in which the number of times for performing the step-movement (consequently, the number of times for decelerating and accelerating the wafer stage WS) is smaller than in the conventional scanning exposure method. Therefore, it is possible to improve the throughput. FIG. 23 shows a flow chart illustrating the outline of an exposure method of the present invention. The first illumination area IR 1 and the second illumination area IR 2 are formed on the mask M, in which the pattern PA is formed, by irradiating the exposure lights ER 1 , ER 2 from the illumination systems IL 1 , IL 2 onto the mask M at a spacing distance in the X direction (S).

Then, the pattern PA on the mask M and the shot area SR 1 (SR 2 ) on the wafer W are positioned with respect to each other via the alignment operation so as to position the pattern PA and the shot area SR 1 with respect to each other before the exposure is started. Subsequently, the mask stage MS is moved in the +X direction (or the −X direction) relative to the first illumination area IR 1 and the second illumination area IR 2 and the wafer stage WS is moved, in synchronization with the movement of the mask stage MS, in the −X direction (or the +X direction) relative to the first illumination area IR 1 and the second illumination area IR 2 (S 2 ). By the synchronized movement of the stages, the pattern PA on the mask M and the shot areas SR 1 , SR 2 on the wafer W are also moved relative to the first illumination area IR 1 and the second illumination area IR 2 . In this movement process, when the pattern PA passes through the first illumination area IR 1 , the image of the pattern PA is projected onto the shot area SR 1 via the projection optical system PL (or the image of the pattern PA by the projection optical system) is projected onto the shot area SR 1 , and when the pattern PA passes through the second illumination area IR 2 , the image of the pattern PA is projected onto the shot area SR 2 via the projection optical system PL.

Next, the wafer stage WS is step-moved in the Y direction such that the next shot areas SR 3 and SR 4 on the wafer W are irradiated with the exposure light EL 1 , EL 2 from the illumination systems IL 1 , IL 2 , respectively (S 3 ). Further, in the shot areas SR 3 and SR 4 , the mask stage MS and the wafer stage W are synchronously moved with respect to the first illumination area IR 2 and the second illumination area IR 2 area, in a same manner as the operation performed for the shot areas SR 1 and SR 2 (but in the opposite direction as that regarding the shot areas SR 1 and SR 2 ) (S 4 ). In such a manner, the shot areas on the wafer W are successively exposed by repeating the synchronous movement and the stepping movement.

In the first embodiment, the mask stage MS constructs the mask-moving section which is movable in the X direction while holding the mask M, and the wafer stage WS constructs the substrate-moving section which is movable in the X direction in synchronization with the mask stage MS while holding the wafer (photosensitive substrate) W. The pair of mask blinds MB 1 , MB 2 , the blind-driving systems BD 1 , BD 2 , and the controller CR construct the restricting section which restricts the first projected image and the second projected image of the pattern of the mask M projected onto the wafer W to be within the first projection area ER 1 and the second projection area ER 2 respectively.

In the first embodiment, the restricting section (MB 1 , MB 2 , BD 1 , BD 2 , CR) sets or defines the sizes (sizes in the X direction) of the first projection area ER 1 and the second projection area ER 2 based on the movement information corresponding to the movement position of the mask stage MS in the X direction (in the scanning direction) and the movement position of the wafer stage WS in the X direction (in general, in the direction corresponding to the scanning direction of the mask stage MS). The restricting section (MB 1 , MB 2 , BD 1 , BD 2 , CR) includes the mask blinds MB 1 , MB 2 as the light-shielding members provided movably in the direction intersecting the optical paths for the exposure lights, the blind-driving systems BD 1 , BD 2 and the controller CR as the shielding controllers to set or define the positions of the light-shielding members with respect to the optical paths for the exposure lights based on the movement information.

In the first embodiment, the projection optical system PL forms the first illumination area (first conjugate area) IR 1 optically conjugate with the first projection area ER 1 and the second illumination area (second conjugate area) IR 2 optically conjugate with the second projection area ER 2 , with the spacing distance in the X direction based on the size S in the X direction of the first shot area SR 1 (or the second shot area SR 2 ), the spacing distance T in the X direction between the first projection area ER 1 and the second projection area ER 2 , the spacing distance K in the X direction between the first shot area SR 1 and the second shot area SR 2 , and the magnitude β of the projection magnification of the projection optical system PL. The illumination systems IL 1 , IL 2 irradiate the exposure lights EL 1 and EL 2 onto the wafer W via the first illumination area IR 1 and the second illumination area IR 2 , respectively.

FIG. 12 shows the construction of an exposure apparatus according to a modification of the first embodiment. In the modification shown in FIG. 12 , the pair of illumination systems IL 1 , IL 2 provided in the first embodiment are integrated into an illumination system IL which is common to the first illumination area IR 1 and the second illumination area IR 2 . Further, the field lenses L 11 , L 21 provided in the first embodiment are integrated into a field lens LC 1 which is common to the first imaging system G 1 and the second imaging system G 2 . Further, the flat reflecting mirrors FM 1 , FM 2 provided in the first embodiment are integrated into one deflecting member PM 2 which has a reflecting surface R 3 for the first imaging system G 1 and a reflecting surface R 4 for the second imaging system G 2 .

FIG. 13 shows the construction of an exposure apparatus according to a second embodiment of the present invention. The second embodiment is constructed similarly to the first embodiment. However, in the second embodiment, the construction of the projection optical system PL is different from that of the first embodiment, and the operation of the scanning exposure is consequently different from that of the first embodiment as well. In FIG. 13 , the constitutive parts or components, which have the same or equivalent functions as those of the first embodiment shown in FIG. 1 , are designated by the same reference numerals as those used in FIG. 1 . The construction and the function of the second embodiment will be explained below while taking notice of the feature different from that of the first embodiment.

The projection optical system PL of the second embodiment includes a first front side imaging system GF 1 which forms a first front side intermediate image of the pattern illuminated with an exposure light EL 1 in a first illumination area IR 1 , a second front side imaging system GF 2 which forms a second front side intermediate image of the pattern illuminated with an exposure light EL 2 in a second illumination area IR 2 , a first rear side imaging system GR 1 which forms a first rear side intermediate image based on the first front side intermediate image, a second rear side imaging system GR 2 which forms a second rear side intermediate image based on the second front side intermediate image, and a third imaging system G 3 which forms a projected image of the pattern in a first projection area ER 1 based on the first rear side intermediate image and which forms a projected image of the pattern in a second projection area ER 2 based on the second rear side intermediate image. The third imaging system G 3 is a dioptric optical system, and the optical axis AX 3 thereof is coincident with the reference optical axis AX of the projection optical system PL.

The first front side imaging system GF 1 and the second front side imaging system GF 2 are mutually constructed in the same manner, and are dioptric optical systems which are provided symmetrically in relation to the YZ plane including the optical axis AX 3 of the third imaging system G 3 (as well as the reference optical axis AX). The first rear side imaging system GR 1 and the second rear side imaging system GR 2 are mutually constructed in the same manner, and are catadioptric optical systems which are provided symmetrically in relation to the YZ plane including the optical axis AX 3 of the third imaging system G 3 . Specifically, the first rear side imaging system GR 1 (second rear side imaging system GR 2 ) is provided with a lens group and a concave reflecting mirror CM 1 (CM 2 ) as referred to in an order of the incidence of the light.

A deflecting member PM 3 , which has a reflecting surface R 5 , is arranged in the optical path between the first front side imaging system GF 1 and the first rear side imaging system GR 1 . A deflecting member PM 4 , which has a reflecting surface R 6 , is arranged in the optical path between the second front side imaging system GF 2 and the second rear side imaging system GR 2 . A deflecting member PM, which has reflecting surfaces R 1 , R 2 , is arranged in the optical paths between the first and second rear side imaging systems GR 1 , GR 2 and the third imaging system G 3 .

In the projection optical system PL of the second embodiment, the light, which comes from the pattern illuminated with the exposure light EL 1 in the first illumination area IR 1 , forms the first front side intermediate image via the first front side imaging system GF 1 . The first front side intermediate image is, for example, a reduction image of the mask pattern, and the image is inverted in the X direction and the Y direction. The light, which comes from the first front side intermediate image, is reflected by the reflecting surface R 5 of the deflecting member PM 3 to form the first rear side intermediate image via the first rear side imaging system GR 1 . The first rear side intermediate image is, for example, a substantially 1× magnification image of the first front side intermediate image. The light, which comes from the first rear side intermediate image, is reflected by the reflecting surface R 1 of the deflecting member PM to form the projected image of the pattern in the first projection area ER 1 on the wafer W via the third imaging system G 3 . The first projected image is, for example, a reduction image of about ¼ of the mask pattern, and the image is erected in the X direction and inverted in the Y direction.

Similarly, the light, which comes from the pattern illuminated with the exposure light EL 2 in the second illumination area IR 2 , forms the second front side intermediate image via the second front side imaging system GF 2 . The second front side intermediate image is, for example, a reduction image of the mask pattern, and the image is inverted in the X direction and the Y direction in the same manner as the first front side intermediate image described above. The light, which comes from the second front side intermediate image, is reflected by the reflecting surface R 6 of the deflecting member PM 4 to form the second rear side intermediate image via the second rear side imaging system GR 2 . The second rear side intermediate image is, for example, a substantially 1× magnification image of the second front side intermediate image in the same manner as the first rear side intermediate image. The light, which comes from the second rear side intermediate image, is reflected by the reflecting surface R 2 of the deflecting member PM to form the projected image of the pattern in the second projection area ER 2 on the wafer W via the third imaging system G 3 . The second projected image is, for example, a reduction image of about ¼ of the mask pattern, and the image is erected in the X direction and inverted in the Y direction in the same manner as the first projected image.

As described above, in the second embodiment, unlike the first embodiment, the +X direction (or the −X direction) in relation to the mask stage MS and the +X direction (or the −X direction) in relation to the wafer stage WS optically correspond to one another via the projection optical system PL. Therefore, in the second embodiment, when the scanning exposure is performed for each of the shot areas, then the mask stage MS is moved in the +X direction (or in the −X direction) while holding the mask M formed with the pattern, and the wafer stage WS is also moved in synchronization with the mask stage MS in the +X direction (or in the −X direction) (i.e., in the same direction as that of the mask stage MS) while holding the wafer W.

That is, in the second embodiment, inversely to the case of the first embodiment, the wafer stage WS is moved in a direction directed from the second projection area ER 2 to the first projection area ER 1 in the X direction (in the direction of the +X direction) in synchronization with the movement in which the mask stage MS is moved in a direction directed from the first illumination area (first conjugate area) IR 1 to the second illumination area (second conjugate area) IR 2 in the X direction (in the direction of the +X direction). In another situation, the wafer stage WS is moved in the direction of the −X direction in synchronization with the movement in which the mask stage MS is moved in the direction of the −X direction.

An explanation will be made below with reference to FIGS. 14 to 17 about the exposure operation in which the scanning exposure is continuously performed for the two adjacent shot areas in the second embodiment. FIGS. 14 to 17 are illustrative of an exemplary case of the scanning exposure in which the mask stage MS is moved in the +X direction and the wafer stage WS is moved in the +X direction by way of example. As depicted by solid lines in FIG. 14 , the scanning exposure is started for the first shot area SR 1 at the point in time at which the edge PAPX on the side in the +X direction of the pattern area PA of the mask M is coincident with the edge IR 1 MX on the side in the −X direction of the first illumination area IR 1 . At the time point of the start of the scanning exposure for the first shot area SR 1 , as depicted by solid lines in FIG. 15 , the edge SR 1 PX on the side in the +X direction of the first shot area SR 1 is coincident with the edge ER 1 MX on the side in the −X direction of the first projection area ER 1 .

Subsequently, as shown by broken lines in FIG. 14 , the scanning exposure for the first shot area SR 1 is completed at the point in time at which the edge PAMX on the side in the −X direction of the pattern area PA is moved to the edge IR 1 PX on the side in the +X direction of the first illumination area IR 1 . At the time point at which the scanning exposure for the first shot area SR 1 is completed, as shown by broken lines in FIG. 15 , the edge SR 1 MX on the side in the −X direction of the first shot area SR 1 is coincident with the edge ER 1 PX on the side in the +X direction of the first projection area ER 1 .

However, the second illumination area IR 2 (as well as the second projection area ER 2 ) is not formed in accordance with the action of the mask blind MB 2 included in the second illumination system IL 2 until at least the edge SR 1 MX on the side in the −X direction of the first shot area SR 1 goes past (passes through) the edge ER 2 MX on the side in the −X direction of the second projection area ER 2 in the reference state so that the first shot area SR 1 is not affected by the second projection area ER 2 when the scanning exposure is performed for the first shot area SR 1 . In other words, the illumination systems IL 1 , IL 2 successively form the first illumination area IR 1 (as well as the first projection area ER 1 ) and the second illumination area IR 2 (as well as the second projection area ER 2 ).

Further, the size of the first illumination area IR 1 in the X direction (as well as the first projection area ER 1 ) is gradually decreased from the predetermined value in the reference state to zero in accordance with the action of the mask blind MB 1 included in the first illumination system IL 1 so that the following second shot area SR 2 is not affected by the first projection area ER 1 during the scanning exposure for the first shot area SR 1 . Specifically, the size in the X direction of the first illumination area IR 1 (as well as the first projection area ER 1 ) starts to be decreased at the point in time at which the edge SR 1 MX on the side in the −X direction of the first shot area SR 1 goes past the edge ER 1 MX on the side in the −X direction of the first projection area ER 1 ; and the size in the X direction of the first illumination area IR 1 (as well as the first projection area ER 1 ) is decreased to zero so that the second shot area SR 2 is not affected by the first projection area ER 1 .

The scanning exposure for the second shot area SR 2 is started at the point in time at which the mask stage MS is further moved in the +X direction and the edge PAPX on the side in the +X direction of the pattern area PA is coincident with the edge IR 2 MX on the side in the −X direction of the second illumination area IR 2 as depicted by solid lines in FIG. 16 . At the time point at which the scanning exposure is started for the second shot area SR 2 , the edge SR 2 PX on the side in the +X direction of the second shot area SR 2 is coincident with the edge ER 2 MX on the side in the −X direction of the second projection area ER 2 , as depicted by solid lines in FIG. 17 . However, prior to the start of the scanning exposure for the second shot area SR 2 , the size in the X direction of the second illumination area IR 2 (as well as the second projection area ER 2 ) is gradually increased from zero to the predetermined value in the reference state in accordance with the action of the mask blind MB 2 while preventing the first shot area SR 1 from being affected by the second projection area ER 2 .

Subsequently, as depicted by broken lines in FIG. 16 , the scanning exposure for the second shot area SR 2 is completed at the point in time at which the edge PAMX on the side in the −X direction of the pattern area PA is moved to the edge IR 2 PX on the side in the +X direction of the second illumination area IR 2 . At the time point at which the scanning exposure is completed for the second shot area SR 2 , the edge SR 2 MX on the side in the −X direction of the second shot area SR 2 is coincident with the edge ER 2 PX on the side in the +X direction of the second projection area ER 2 , as depicted by broken lines in FIG. 17 .

The size in the X direction of the second illumination area IR 2 (as well as the second projection area ER 2 ) is gradually decreased from the predetermined value in the reference state to zero in accordance with the action of the mask blind MB 2 included in the second illumination system IL 2 so that the following third shot area (not shown) is not affected by the second projection area ER 2 during or after the completion of the scanning exposure for the second shot area SR 2 . Specifically, the size in the X direction of the second illumination area IR 2 (as well as the second projection area ER 2 ) starts to be decreased at the point in time at which the edge SR 2 MX on the side in the −X direction of the second shot area SR 2 goes past the edge ER 2 MX on the side in the −X direction of the second projection area ER 2 ; and the size in the X direction of the second illumination area IR 2 (as well as the second projection area ER 2 ) is decreased to zero so that the third shot area is not affected by the second projection area ER 2 .

Next, an explanation will be made with reference to FIGS. 18 and 19 about the condition required to perform the scanning exposure continuously for the two adjacent shot areas SR 1 , SR 2 in the second embodiment. In order to simplify the explanation, FIG. 18 shows a state that the edge PAMX on the side in the −X direction of the pattern area PA arrives at the center IR 1 C of the first illumination area IR 1 . FIG. 19 shows a state that the edge SR 1 MX on the side in the −X direction of the first shot area SR 1 arrives at the center ER 1 C of the first projection area ER 1 corresponding to FIG. 18 .

With reference to FIG. 18 , reference symbol “U” indicates the center-to-center spacing distance in the X direction between the center IR 1 C of the first illumination area IR 1 and the center IR 2 C of the second illumination area IR 2 . Reference symbol “P” indicates the size in the X direction of the pattern area PA, and reference symbol “D” indicates the size in the X direction of each of the first illumination area IR 1 and the second illumination area IR 2 . Reference symbol “AX” indicates the distance in the X direction between the edge PAPX on the side in the +X direction of the pattern area PA and the center IR 2 C of the second illumination area IR 2 in the state shown in FIG. 18 .

With reference to FIG. 19 , reference symbol “S” indicates the size in the X direction of each of the first shot area SR 1 and the second shot area SR 2 , and reference symbol “K” indicates the spacing distance in the X direction between the first shot area SR 1 and the second shot area SR 2 . Reference symbol “V” indicates the center-to-center spacing distance in the X direction between the center ER 1 C of the first projection area ER 1 and the center ER 2 C of the second projection area ER 2 , and reference symbol “T” indicates the spacing distance in the X direction between the first projection area ER 1 and the second projection area ER 2 .

In this case, the relationships hold as shown by the following expressions (5) to (8).

U=P−ΔX   (5)

P=S/β   (6)

Δ X =( V−K )/β  (7)

V=β×D+T   (8)

Here, the expressions (5), (6) and (8) define the relationship derived from the distance in the X direction between the first illumination area IR 1 and the second illumination area IR 2 , the length (width) in the X direction of each of the first illumination area IR 1 and the second illumination area IR 2 , the length in the X direction of the pattern area PA, the distance in the X direction between the first projection area ER 1 and the second projection area ER 2 and the length (width) in the X direction of each of the first projection area ER 1 and the second projection area ER 2 . The expression (7) shows the relationship among the length in the X direction of each of the first shot area SR 1 and the second shot area SR 2 , the length in the X direction of the pattern area PA and the spacing distance in the X direction between the first shot area SR 1 and the second shot area SR 2 with respect to the projection magnification β, etc, and the expression (7) defines the following condition. That is, in the arrangements shown in FIGS. 18 and 19 , the edge PAPX on the side in the +X direction of the pattern PA should already arrive at the center IR 2 C of the second illumination area IR 2 before the pattern area PA passes through the first illumination area IR 1 and the scanning exposure for the first shot area SR 1 by the first projection area ER 1 is completed. When the edge PAPX on the side in the +X direction of the pattern PA arrives at the center IR 2 C of the second illumination area IR 2 , it is necessary that the edge SR 2 PX on the side in the +X direction of the second illumination area IR 2 is positioned at the center ER 2 C of the second projection area ER 2 . Namely, in order that the image of the pattern PA is correctly transferred onto the second shot area SR 2 , the second shot area SR 2 and the pattern PA should be aligned with respect to each other. Accordingly, while the pattern PA on the mask M is moved by AX shown in FIG. 18 , the second shot area SR 2 on the wafer W is moved by V-K shown in FIG. 18 . Therefore, when the projection magnification β is considered, the relationship of ΔX=(V−K)/P is determined.

The following conditional expressions (D), (E), (F) are obtained from the relationships expressed in the expressions (5) to (8). The conditional expressions (D), (E), (F) differ only in the expression forms. When one conditional expression of the conditional expressions is satisfied, the other two conditional expressions are also satisfied.

U =( S+K−V )/β  (D)

U=P +( K−V )/β  (E)

U=P−D −( T−K )/β  (F)

As described above, the second embodiment is constructed so that the center-to-center spacing distance U in the X direction, which is provided between the center IR 1 C of the first illumination area IR 1 as the first conjugate area optically conjugate with the first projection area ER 1 via the projection optical system PL and the center IR 2 C of the second illumination area IR 2 as the second conjugate area optically conjugate with the second projection area ER 2 via the projection optical system PL, satisfies the conditional expression (D) as well as the conditional expressions (E), (F). With this, the scanning exposure can be continuously performed for the two shot areas SR 1 , SR 2 which are adjacent to each other (which are different) in the X direction, by performing the synchronous movement in the X direction of the mask stage MS and the wafer stage WS once (synchronous movement including no step movement in the Y direction). As a result, also in the exposure apparatus of the second embodiment, the scanning exposure can be continuously performed for the two adjacent shot areas in the same manner as in the first embodiment. Therefore, it is possible to achieve the improvement in the throughput in relation to the scanning exposure based on, for example, the simple scanning procedure as shown in FIG. 10 . In the second embodiment, the center-to-center spacing distance U in the X direction between the pair of conjugate areas is smaller than that in the first embodiment. Therefore, it is easy to integrate the illumination systems IL 1 , IL 2 into one unit.

FIG. 20 shows the construction of an exposure apparatus according to a modification of the second embodiment. In the second embodiment shown in FIG. 13 , the center of the first illumination area IR 1 and the optical axis AXF 1 of the first front side imaging system GF 1 are substantially coincident with each other, and the center of the second illumination area IR 2 and the optical axis AXF 2 of the second front side imaging system GF 2 are substantially coincident with each other. On the other hand, in the modification shown in FIG. 20 , the center of the first illumination area IR 1 is eccentrically positioned in the +X direction from the optical axis AXF 1 , and the center of the second illumination area IR 2 is eccentrically positioned in the −X direction from the optical axis AXF 2 . In other words, the center of the first illumination area IR 1 and the center of the second illumination area IR 2 are eccentrically positioned inwardly toward the reference optical axis AX. Owing to this construction, it is easy to arrange the first front side imaging system GF 1 and the second front side imaging system GF 2 without allowing them to mechanically interfere with each other.

In the second embodiment, the three-times imaging type catadioptric optical system, which includes the lenses (transmissive optical members) eccentrically arranged with respect to the reference optical axis AX as shown in FIG. 13 , is used as the projection optical system for forming the mask pattern images (projected images) erected in the X direction. However, there is no limitation to this. As shown in FIGS. 21 and 22 , for example, a catadioptric optical system, in which all transmissive optical members are coaxially arranged along with the reference optical axis AX, can be also applied to the projection optical system of the second embodiment.

A catadioptric optical system shown in FIG. 21 includes a first imaging system G 1 which forms a first intermediate image of the pattern of the mask M illuminated in a first illumination system IL 1 , a second imaging system G 2 which forms a second intermediate image of the pattern illuminated in a second illumination system IL 2 , and a third imaging system G 3 which forms a projected image of the pattern in a first projection area ER 1 based on the first intermediate image and which forms a projected image of the pattern in a second projection area ER 2 based on the second intermediate image. The third imaging system G 3 is a dioptric optical system, and its optical axis AX 3 is coincident with the reference optical axis AX.

The first imaging system G 1 and the second imaging system G 2 are mutually constructed in the same manner, and are catadioptric optical systems provided symmetrically in relation to the YZ plane including the optical axis AX 3 of the third imaging system G 3 (as well as the reference optical axis AX). Specifically, the first imaging system G 1 (second imaging system G 2 ) is provided with a positive lens group LC which is common to the first imaging system G 1 and the second imaging system G 2 , a concave reflecting mirror CM 11 (CM 21 ), and a concave reflecting mirror CM 12 (CM 22 ) as referred to in an order of the incidence of the light. In this case, the positive lens group LC is arranged along with the reference optical axis AX. However, the concave reflecting mirrors CM 11 (CM 21 ), CM 12 (CM 22 ) are arranged eccentrically with respect to the reference optical axis AX.

In the catadioptric optical system shown in FIG. 21 , a light EL 1 , which comes from the pattern illuminated in the first illumination area IR 1 , forms the first intermediate image via the positive lens group LC, the concave reflecting mirror CM 11 , and the concave reflecting mirror CM 12 . The first intermediate image is an image inverted in the X direction and the Y direction. The light, which comes from the first intermediate image, passes through the third imaging system G 3 to form the projected image of the pattern in the first projection area ER 1 on the wafer W. The first projected image is, for example, a reduction image of about ¼ of the mask pattern, and the image is erected in the X direction and the Y direction.

Similarly, a light EL 2 , which comes from the pattern illuminated in the second illumination area IR 2 , forms the second intermediate image via the positive lens group LC, the concave reflecting mirror CM 21 , and the concave reflecting mirror CM 22 . The second intermediate image is an image inverted in the X direction and the Y direction in the same manner as the first intermediate image. The light, which comes from the second intermediate image, passes through the third imaging system G 3 to form the projected image of the pattern in the second projection area ER 2 on the wafer W. The second projected image is, for example, a reduction image of about ¼ of the mask pattern, and the image is erected in the X direction and the Y direction in the same manner as the first projected image.

A catadioptric optical system shown in FIG. 22 has a construction similar to that of the catadioptric optical system shown in FIG. 21 . However, in the catadioptric optical system shown in FIG. 21 , the third imaging system G 3 is the dioptric optical system. On the other hand, in the catadioptric optical system shown in FIG. 22 , the third imaging system G 3 is a catadioptric optical system. The positional relationship in the X direction between the first projection area ER 1 and the second projection area ER 2 formed on the wafer W, which is provided in the catadioptric optical system shown in FIG. 21 , is reverse to that provided in the catadioptric optical system shown in FIG. 22 .

Specifically, in the in the catadioptric optical system shown in FIG. 22 , the third imaging system G 3 is provided with a concave reflecting mirror CM 31 which has a central opening formed about the center of the reference optical axis AX, a concave reflecting mirror CM 32 , and a positive lens group L 3 as referred to in an order of the incidence of the light. In this case, the concave reflecting mirror CM 31 , the concave reflecting mirror CM 32 , and the positive lens group L 3 are arranged along with the reference optical axis AX (optical axis AX 3 ) without being positioned eccentrically.

In the catadioptric optical system shown in FIG. 22 , a light EL 1 , which comes from the pattern illuminated in the first illumination area IR 1 , forms the first intermediate image via the positive lens group LC, the concave reflecting mirror CM 11 , and the concave reflecting mirror CM 12 . The first intermediate image is an image inverted in the X direction and the Y direction. The light, which comes from the first intermediate image, passes along the concave reflecting mirror CM 31 , the concave reflecting mirror CM 32 , and the positive lens group L 3 to form the projected image of the pattern in the first projection area ER 1 on the wafer W. The first projected image is, for example, a reduction image of about ¼ of the mask pattern, and the image is erected in the X direction and the Y direction.

Similarly, a light EL 2 , which comes from the pattern illuminated in the second illumination area IR 2 , forms the second intermediate image via the positive lens group LC, the concave reflecting mirror CM 21 , and the concave reflecting mirror CM 22 . The second intermediate image is an image inverted in the X direction and the Y direction in the same manner as the first intermediate image. The light, which comes from the second intermediate image, passes along the concave reflecting mirror CM 31 , the concave reflecting mirror CM 32 , and the positive lens group L 3 to form the projected image of the pattern in the second projection area ER 2 on the wafer W. The second projected image is, for example, a reduction image of about ¼ of the mask pattern, and the image is erected in the X direction and the Y direction in the same manner as the first projected image.

In each of the catadioptric optical systems shown in FIGS. 21 and 22 , a lens group (broad concept including one lens), which is common to the first imaging system G 1 and the second imaging system G 2 , can be arranged along with the reference optical axis AX in the optical paths between the concave reflecting mirrors CM 11 , CM 21 and the concave reflecting mirrors CM 12 , CM 22 .

In the respective embodiments described above, the shape of the illumination area (IR 1 , IR 2 ) formed on the object plane PLo of the projection optical system PL is defined, and the shape of the projection area (ER 1 , ER 2 ) formed on the wafer W is consequently defined, in accordance with the action of the movable field diaphragm (MB 1 , MB 2 ) arranged on the pattern conjugate plane optically conjugate with the pattern surface of the mask M in the optical path of the illumination system (IL 1 , IL 2 ; IL). However, there is no limitation to this. For example, it is also allowable to arrange a movable field diaphragm on the pattern conjugate plane (position at which the intermediate image is formed) optically conjugate with the pattern surface of the mask in the optical path of the projection optical system so as to define the shape of the projection area formed on the photosensitive substrate. In this case, the illumination area is not necessarily coincident with the conjugate area optically conjugate with the projection area. Therefore, the conjugate area is used in place of the illumination area in the respective conditional expressions. Alternatively, the following interpretation may be allowable. That is, the illumination area is not an area in which the light flux coming from the illumination system arrives at the object plane of the projection optical system, but the illumination area is an area in which the effective light flux to arrive at the photosensitive substrate via the projection optical system from the illumination system, passes through the object plane of the projection optical system, i.e., the conjugate area. There is no limitation to the field diaphragm mechanism which is mechanically driven (moved). Those usable as the movable field diaphragm include, for example, an element such as a liquid crystal filter in which the light/dark areas can be electrically changed.

In the respective embodiments described above, such a situation is assumed that at least one of the size S in the X direction of each of the shot areas and the spacing distance K in the X direction between the respective shot areas is changed. In this case, it is necessary that any optical adjustment should be performed so that the center-to-center spacing distance U in the X direction, which is provided between the center of the first conjugate area (first illumination area IR 1 in the embodiment) and the center of the second conjugate area (second illumination area IR 2 in the embodiment), satisfies the required conditional expression or expressions. For example, it is considered in the first embodiment that the spacing distance T in the X direction between the first projection area and the second projection area is changed, for example, by the optical adjustment in relation to at least one of the imaging systems G 1 , G 2 and the deflecting member PM, and the center-to-center spacing distance U between the pair of conjugate areas is consequently changed to have the required value.

In the respective embodiments, the mask blinds MB 1 , MB 2 are operated so as to prevent the first shot area SR 1 (or the second shot area SR 2 ) from being exposed by the second projection area ER 2 (or the first projection area ER 1 ). Instead of this, it is allowable to perform the on/off control for the illumination systems IL 1 , IL 2 such that the illumination area IR 1 or the illumination area IR 2 is not illuminated. In this case, the mask blinds MB 1 , MB 2 can be omitted.

The exposure apparatus of each of the embodiments described above is produced by assembling the various subsystems including the respective constitutive elements as defined in claims so that the predetermined mechanical accuracy, electric accuracy and optical accuracy are maintained. In order to secure the various accuracies, those performed before and after the assembling include the adjustment for achieving the optical accuracy for the various optical systems, the adjustment for achieving the mechanical accuracy for the various mechanical systems, and the adjustment for achieving the electric accuracy for the various electric systems. The steps of assembling the various subsystems into the exposure apparatus include, for example, the mechanical connection, the wiring connection of the electric circuits, and the piping connection of the air pressure circuits in correlation with the various subsystems. It goes without saying that the steps of assembling the respective individual subsystems are performed before performing the steps of assembling the various subsystems into the exposure apparatus. When the steps of assembling the various subsystems into the exposure apparatus are completed, the overall adjustment is performed to secure the various accuracies as the entire exposure apparatus. It is desirable that the exposure apparatus is produced in a clean room in which the temperature, the cleanness, etc. are managed.

Next, an explanation will be made about a method for producing a device using the exposure apparatus or the exposure method according to the embodiment described above. FIG. 24 shows a flow chart illustrating steps of producing the semiconductor device. As shown in FIG. 24 , in the steps of producing the semiconductor device, a metal film is vapor-deposited on a wafer W serving as a substrate of the semiconductor device (Step S 40 ), and a surface of the vapor-deposited metal film is coated with a photoresist as a photosensitive material (Step S 42 ). Subsequently, a pattern, which is formed on a mask M as shown in the flow chart of FIG. 23 , is transferred to respective shot areas on the wafer W by using the exposure apparatus or the exposure method of the embodiment described above (Step S 44 : exposure step), and the development is performed for the wafer W for which the transfer has been completed, i.e., the development is performed for the photoresist onto which the pattern has been transferred (Step S 46 : development step)

After that, the processing such as the etching, etc. is performed for the surface of the wafer W by using the resist pattern as the mask for processing the wafer, the resist pattern having been formed on the surface of the wafer W in Step S 46 (Step S 48 : processing step). The term “resist pattern” herein refers to the photoresist layer (transfer pattern layer) formed with protrusions and recesses having shapes corresponding to the pattern transferred by the exposure apparatus or the exposure method of the embodiment described above, wherein the recesses penetrate through the photoresist layer. In Step S 48 , the surface of the wafer W is processed via the resist pattern. The processing, which is performed in Step S 48 , includes, for example, at least one of the etching for the surface of the wafer W and the formation of the film such as the metal film. In Step S 44 , the exposure apparatus or the exposure method of the embodiment described above transfers the pattern by using the wafer W, on which the photoresist is coated, as the photosensitive substrate.

FIG. 25 shows a flow chart illustrating steps of producing a liquid crystal device such as a liquid crystal display element or the like. As shown in FIG. 25 , in the steps of producing the liquid crystal device, a pattern-forming step (Step S 50 ), a color filter-forming step (Step S 52 ), a cell-assembling step (Step S 54 ), and a module-assembling step (Step S 56 ) are successively performed. In the pattern-forming step of Step S 50 , a predetermined pattern, which includes, for example, a circuit pattern and an electrode pattern, is formed on a glass substrate coated with a photoresist as a photosensitive substrate by using the exposure apparatus or the exposure method of the embodiment described above. The pattern-forming step includes an exposure step of transferring the pattern to a photoresist layer by using the exposure apparatus or the exposure method of the embodiment described above, a development step of performing the development of the photosensitive substrate to which the pattern has been transferred, i.e., the development of the photoresist layer on the glass substrate to form the photoresist layer (transfer pattern area) having the shape corresponding to the pattern, and a processing step of processing the surface of the glass substrate via the developed photoresist layer.

In the color filter-forming step of Step S 52 , a color filter is formed, in which a large number of sets of three dots corresponding to R (Red), G (Green), and B (Blue) are arranged in a matrix form, or a plurality of sets of filters of three stripe of R, G, and B are arranged in the horizontal scanning direction. In the cell-assembling step of Step S 54 , a liquid crystal panel (liquid crystal cell) is assembled by using the glass substrate formed with the predetermined pattern in Step S 50 and the color filter formed in Step S 52 . Specifically, the liquid crystal panel is formed, for example, by injecting the liquid crystal into a space between the glass substrate and the color filter. In the module-assembling step of Step S 56 , various parts, which include a back light, an electronic circuit for performing the display operation of the liquid crystal panel, etc., are attached to the liquid crystal panel assembled in Step S 54 .

The present invention is not limited to the application to the exposure apparatus for producing the semiconductor device or the liquid crystal device. The present invention is also widely applicable, for example, to exposure apparatuses for display apparatuses including, for example, a plasma display as well as to exposure apparatuses for producing various devices including, for example, an image pickup device (CCD or the like), a micromachine, a thin film magnetic head, and a DNA chip. Further, the present invention is also applicable to the exposure step (exposure apparatus) adopted when masks (photomasks, reticles or the like) formed with mask patterns of various devices are produced by using the photolithography step.

In each of the embodiments as described above, it is allowable to adopt the liquid immersion method as disclosed, for example, in International Publication No. 1999/49504, Japanese Patent Application Laid-open No. 2004-289126 (corresponding to United States Patent Application Publication No. 2004/0165159), etc. Namely, it is allowable to form, by using a liquid immersion system, a liquid immersion area of a liquid on a substrate P (wafer W) such that the liquid immersion area covers the first and second projection areas ER 1 , ER 2 , and to irradiate the first and second exposure lights EL 1 , EL 2 onto the substrate P through the liquid in the liquid immersion area. The liquid immersion system may be arranged, for example, in the vicinity of the optical paths of the exposure lights between a final optical element (end optical element) of the projection optical system PL and the substrate P, and the liquid immersion system may be provided with a liquid supply member having a supply port through which the liquid is supplied with respect to the optical paths and a liquid recovery member having a recovery port through which the liquid is recovered from the optical paths. Note that it is not necessarily indispensable that a part of the liquid immersion system (for example, the liquid supply member and/or the liquid recovery member) is provided on the exposure apparatus. It is allowable to substitutively use, for example, the equipment of the factory, etc. in which the exposure apparatus is installed. Further, the construction of the liquid immersion system is not limited to those described above, and it is allowable to use those as disclosed, for example, in European Patent Publication No. 1420298, International Publication No. 2004/055803, International Publication No. 2004/057590, International Publication No. 2005/029559 (corresponding to United States Patent Application Publication No. 2006/0231206), International Publication No. 2004/086468 (corresponding to United States Patent Application Publication No. 2005/0280791), Japanese Patent Application Laid-open No. 2004-289126 (corresponding to U.S. Pat. No. 6,952,253), etc. As a liquid used in the liquid immersion method, it is allowable to use water (pure or purified water), and to use those other than water, for example, fluorine-based fluids such as fluorine-based oil and perfluoropolyether (PFPE), or cedar oil, etc.

Further, the present invention is also applicable to an exposure apparatus of the multi-stage type provided with a plurality of substrate stages as disclosed, for example, in Japanese Patent Application Laid-open No. 10-163099, Japanese Patent Application Laid-open No. 10-214783 (corresponding to U.S. Pat. Nos. 6,341,007, 6,400,441, 6,549,269 and 6,590,634), Published Japanese Translation of PCT International Publication for Patent Application No. 2000-505958 (corresponding to U.S. Pat. No. 5,969,441), etc. Furthermore, the present invention is applicable also to an exposure apparatus including a substrate stage which holds the substrate and a measurement stage on which a measurement member (for example, a reference member formed with a reference mark and/or various photoelectronic sensors) is provided, as disclosed, for example, in Japanese Patent Application Laid-open No. 11-135400 (corresponding to International Publication No. 1999/23692) and Japanese Patent Application Laid-open No. 2000-164504 (corresponding to U.S. Pat. No. 6,897,963).

With respect to the various U.S. Patents and United States Patent Application Publications identified in the specification of this application, the contents of these United States Patents and United States Patent Application Publications are incorporated herein by reference within a range of permission of the domestic laws and ordinances of the state or country in which the present application is filed, in relation to those other than those having been specifically and explicitly incorporated herein by reference as well.

According to the present invention, the substrate (wafer) can be exposed with high efficiency. Accordingly, a device having a high-density and complicated pattern and used in a liquid crystal display element, micro machine, etc. can be produced with high throughput. Therefore, the present invention will remarkably contribute to the international development of the precision mechanical equipment industry including the semiconductor industry.