Methods of forming patterns in semiconductor devices using photo resist patterns

A claim of priority is made to Korean Patent Application No. 10-2006-0016935, filed on Feb. 21, 2006, the disclosure of which is hereby incorporated by reference in its entirety.

The present invention relates generally to semiconductor devices and, more particularly, to methods of forming patterns in semiconductor devices.

After forming certain layers on a semiconductor substrate, an etch mask is utilized to pattern certain layers through a photo resist trimming process. While the photo resist trimming process is performed, the thickness of a photo resist pattern may be reduced. Moreover, the etch mask may also be etched away during the process, depending on an etching selectivity ratio of the layers and the etch mask. Therefore, the etch mask may not form the layers as a target pattern.

FIG. 1 is a plan view of a semiconductor device illustrating a method of manufacturing semiconductor devices using a conventional photo resist trimming process.

Referring to FIG. 1 , a layer to be etched away is formed on a semiconductor substrate P 1 . The layer to be etched away may be a polysilicon layer for forming a gate of a transistor, or a nitride layer for forming a hard mask. After forming the layer to be etched away, a photo resist layer is formed on the layer to be etched away. Finally, the photo resist layer is exposed and developed by using a photo mask having a designed pattern so that photo resist patterns P 2 are formed. The photo resist patterns P 2 may be inferior. For example, there may be a bridge pattern D 1 connecting the patterns P 2 , or there may be a deformity pattern D 2 having a wider width.

A photo resist trimming process may be performed after the semiconductor substrate P 1 is loaded on etching equipment, in order to achieve minimum marginal resolution critical dimension (CD) of the photo resist patterns P 2 . As a result, final photo resist patterns P 2 ′ on which CD is much reduced, may be formed. The bridge inferior pattern D 1 may be removed by the photo resist trimming process. The deformity pattern D 2 , however, may not be removed by the photo resist trimming process. Although the absolute width of the deformity inferior pattern D 2 may be reduced, the relative width between the deformity pattern D 2 and neighboring patterns may remain.

Moreover, the line width of the final photo resist patterns P 2 ′ is reduced by the photo resist trimming process, but the thickness of the final photo resist patterns P 2 ′ is thinner due to etching. Therefore, while the layer to be etched away is etched by using the final photo resist patterns P 2 ′, the thickness of the final photo resist patterns P 2 ′ is getting thinner as the etching process is going on. In conclusion, the final photo resist patterns P 2 ′ may not perform an etching protection layer so that the pattern shape of the layer to be etched away may be abnormal, or a portion of the layer to be etched away may be removed in worst case.

As described above, in order to overcome marginal resolution of photo equipment, and reduce the pattern width of a layer to be etched away, a photo resist trimming process is performed. As a result, it may reduce the CD of photo resist patterns and remove bridge pattern D 1 . However, photo resist patterns may not perform the formation of etching protection layers normally so that it may cause deterioration of pattering characteristics and difficulty in removing deformity pattern D 2 . Moreover, it may be impossible to use the photo resist trimming process in order to both remove the bridge pattern and maintain the CD of pattern as it was.

According to some embodiments of the invention, a method of forming patterns in semiconductor devices by using photo resist patterns is provided. This method comprises forming photo resist patterns on a substrate. Inferior patterns are selected among the photo resist patterns. The inferior patterns are eliminated or shrunken by irradiating the selected inferior patterns with an electron beam.

According to some embodiments of the invention, the method further comprises detecting the inferior patterns with a preliminary electron beam before either eliminating or shrinking the inferior patterns. The preliminary electron beam may utilize reduced energy in order to measure an image. The subsequent electron beam may utilize higher energy than the energy of the preliminary electron beam.

According to some embodiments of the invention, the inferior patterns may be burned out by the electron beam.

According to some embodiments of the invention, the inferior patterns may undergo a polymer crosslinking reaction in response to being irradiated by the electron beam.

According to some embodiments of the invention, accelerating voltages of the electron beam may be between about 1 volt and 400 kilovolts.

According to some embodiments of the invention, a layer to be etched away may be formed on the substrate before forming the photo resist patterns. The layer to be etched away may be etched by using photo resist patterns in which the inferior patterns are eliminated or shrunken, as an etch mask.

According to some embodiments of the invention, a method of forming patterns in semiconductor devices is provided. This method comprises loading a substrate having photo resist patterns on a scanning electron microscope (SEM). Inferior patterns are selected among the photo resist patterns. The inferior patterns are either eliminated or shrunken by irradiating with an electron beam.

According to some embodiments of the invention, the location of inferior patterns may be detected by irradiating the substrate with a preliminary electron beam before selecting inferior patterns among the photo resist patterns. The preliminary electron beam may utilize reduced energy in order to measure an image. The electron beam may utilize higher energy than the energy of the preliminary electron beam.

According to some embodiments of the invention, the inferior patterns may be burned out by the electron beam.

According to some embodiments of the invention, the inferior patterns may undergo a polymer crosslinking reaction in response to being irradiated by the electron beam.

According to some embodiments of the invention, accelerating voltages of the electron beam may be between about 1 volt and 400 kilovolts.

The invention is described below in relation to several embodiments illustrated in the accompanying drawings. Throughout the drawings like reference numbers indicate like exemplary elements, components, or steps, and the thickness of layers is exaggerated for clarity. In the drawings:

FIG. 1 is a plan view of a semiconductor device illustrating a method of manufacturing semiconductor devices using a conventional photo resist trimming process.

FIG. 2 is a process flow chart illustrating methods of forming patterns in semiconductor devices according to embodiments of the present invention.

FIG. 3 is a plan view of a semiconductor device illustrating methods of forming patterns in semiconductor device according to embodiments of the present invention.

FIG. 4 is a plan view of a photo mask used for forming patterns in semiconductor devices, according to embodiments of the present invention.

FIGS. 5 a through 5 e are cross-sectional views taken along the cutting line I-I′ of FIG. 3 and that illustrate methods of forming patterns in semiconductor devices according to embodiments of the present invention.

Exemplary embodiments of the invention are described below with reference to the corresponding drawings. These embodiments are presented as teaching examples. The actual scope of the invention is defined by the claims that follow.

The present invention is described more fully hereinafter with reference to the accompanying drawings, in which example embodiments of the invention are shown. The present invention may, however, be embodied in many different forms and should not be construed as limited to the example embodiments set forth herein. Rather, these example embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. In the drawings, the sizes and relative sizes of layers and regions may be exaggerated for clarity.

It will be understood that when an element or layer is referred to as being “on,” “connected to,” “coupled to” or “responsive to” another element or layer, it can be directly on, connected, coupled or responsive to the other element or layer or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly connected to,” “directly coupled to” or “directly responsive to” another element or layer, there are no intervening elements or layers present. Like numbers refer to like elements throughout. As used herein, the term “and/or” includes any and all combinations (mixtures) of one or more of the associated listed items and may be abbreviated as “/”.

It will be understood that, although the terms first, second, third etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “below” can encompass both an orientation of above and below. The structure and/or the device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Example embodiments of the present invention are described herein with reference to plan view illustrations that are schematic illustrations of idealized embodiments of the present invention. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, example embodiments of the present invention should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of the present invention unless expressly so defined herein.

It should also be noted that in some alternate implementations, the functionality of a given block may be separated into multiple blocks and/or the functionality of two or more blocks may be at least partially integrated.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present application, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Referring to FIGS. 2 , 3 , 4 and 5 a , a layer 10 to be etched away is formed on a substrate 5 . The substrate 5 may include a semiconductor substrate and/or a quartz substrate. When the substrate 5 is a semiconductor substrate, the layer 10 to be etched away may include all types of layers used in semiconductor manufacturing, such as, for example, pad nitride layers, gate layers, etc. The layer 10 to be etched away may include a shade layer like chrome, etc., when the substrate 5 is a quartz substrate. A photo resist layer 15 is formed on a substrate having the layer 10 to be etched away (Step F 01 of FIG. 2 ). The photo resist layer 15 , may be formed, for example, by using either photo resist solution for 193 nm wavelength laser light or photo resist solution for 248 nm wavelength laser light. A photo resist layer 15 is exposed by using a photo mask 120 , as shown in FIG. 4 (Step F 02 of FIG. 2 ). The photo mask 120 may include both a quartz substrate 100 and a shade pattern 115 arranged on the quartz substrate 100 .

Referring to FIGS. 2 , 3 and 5 b , photo resist patterns 15 ′ are formed as the photo resist layer 15 is developed (Step F 03 of FIG. 2 ). The photo resist patterns 15 ′ may include inferior patterns. The inferior patterns may include a bridge pattern B 1 , and deformity pattern B 2 that is patterned in wider CD than originally designed. Both the bridge pattern B 1 and the deformity pattern B 2 may be caused by remains of the photo resist layer 15 that have to be removed by both exposing and developing processes. Or, in case the photo mask 120 has defects itself, the defect patterns are overall reflected to the photo resist layer 15 so that it may cause these inferior patterns.

Referring to FIGS. 2 , 3 and 5 c , a substrate having photo resist patterns 15 ′ is loaded in scanning electron microscope (SEM) equipment (Step F 04 of FIG. 2 ). A preliminary electron beam EB 1 is irradiated on the substrate so that it may generate a first image W 1 (Step F 05 of FIG. 2 ). The preliminary electron beam EB 1 may utilize reduced energy to measure an image. However, the photo resist patterns 15 ′ exposed to the preliminary electron beam EB 1 may be shrunken, while the first image W 1 is generated by the preliminary electron beam EB 1 . Therefore, it is desirable to quickly process generation of the first image W 1 in order not to exert an influence on CD.

A determination is made if both the bridge inferior pattern B 1 and deformity pattern B 2 exist within the first image W 1 (Step F 06 of FIG. 2 ). In case there are both the bridge pattern B 1 and the deformity pattern B 2 in the first image W 1 , either the bridge pattern B 1 or the deformity pattern B 2 is selected and a second image W 2 may be generated (Step F 07 of FIG. 2 ). The second image W 2 may include the bridge pattern B 1 . In case there is not both the bridge pattern B 1 and deformity pattern B 2 , the preliminary electron beam EB 1 is moved to another position in the substrate so as to confirm existence of the bridge pattern B 1 and the deformity pattern B 2 through a new image (Step F 07 ′ of FIG. 2 ). Moreover, after the first image W 1 is generated, the CD of the photo resist patterns 15 ′ may be measured by using the first image W 1 .

Referring to FIGS. 2 , 3 and 5 d , the substrate is irradiated with an electron beam EB 2 to generate a second image W 2 (Step F 08 of FIG. 2 ). The electron beam EB 2 may irradiate with higher energy than the preliminary electron beam EB 1 . As a result, while the electron beam EB 2 is irradiated, the bridge pattern B 1 may be burned out (Step F 09 of FIG. 2 ). Acceleration voltage of the electron beam EB 2 may be between about 1 volt and 1000 kilovolts. Preferably, the acceleration voltage of the electron beam EB 2 may be between about 1 volt and 400 kilovolts.

Thereafter, the electron beam EB 2 is adjusted to the energy of the preliminary electron beam EB 1 so that it may detect both the bridge pattern B 1 and deformity pattern B 2 at other areas and generate a third image W 3 . The third image W 3 may include the deformity pattern B 2 patterned to wider CD than originally designed. A miniature electron beam with energy that is higher than the preliminary electron beam EB 1 and lower than the electron beam EB 2 , may be utilized to irradiate the substrate to generate the third image W 3 . The deformity inferior pattern B 2 , while the miniature electron beam is irradiating, may be shrunken due to a reaction of polymer cross linking. As a result, a shrunken pattern B 2 ′ having reduced CD may be formed. It adjusts the energy of the miniature electron beam so that the CD of the shrunken pattern B 2 ′ may be either equal or close to the originally designed pattern.

Each CD of the photo resist patterns 15 ′ may be adjusted by using the miniature electron beam. In order to test the characteristics of transistors by CD of gate electrodes, for example, electron beams having different energies are irradiated to the photo resist patterns 15 ′ so that each of CDs may be formed differently.

By repeatedly performing processing steps F 05 through F 09 of FIG. 2 , all of the bridge inferior pattern B 1 and deformity pattern B 2 may be removed or reduced. Therefore, final photo resist patterns 15 ″ may be formed.

Referring to FIGS. 2 , 3 and 5 e , the layer 10 ′ to be etched away is etched by using the final photo resist patterns 15 ″ as an etch mask, so that patterns of layer 10 ′ to be etched away may be formed. Through either removing or reducing the bridge pattern B 1 and deformity pattern B 2 on the photo resist patterns 15 ′ by using an electron beam, the patterns of the layer 10 ′ to be etched away may be either same or similar patterns as originally designed. For example, when the patterns of the layer 10 ′ to be etched away are gate patterns and the bridge pattern B 1 still remains in it, the bridge pattern B 1 may be removed in advance at formation stage of the final photo resist patterns 15 ″, so that it may increase the yield of semiconductor devices and may protect any CD reduction of unwanted patterns by either eliminating or shrinking any inferior patterns.

The foregoing exemplary embodiments are teaching examples. Those of ordinary skill in the art will understand that various changes in form and details may be made to the exemplary embodiments without departing from the scope of the present invention as defined by the following claims.