Semiconductor integrated circuit device

1. Field of the Invention

The present invention relates to a semiconductor integrated circuit device provided with, for example, a macro cell having a multi-layer construction.

The present application claims priority of Japanese Patent Application No. 2001-225204 filed on Jul. 25, 2001, which is hereby incorporated by reference.

2. Description of the Related Art

A semiconductor integrated circuit device such as a system LSI (Large Scale Integrated Circuit) has such a configuration that a plurality of macro cells having a specific function is formed on a substrate. In each of the macro cells, such elements are formed as a transistor, a resistor, a capacitor, or a like, which are combined to make up a memory circuit of a RAM/DRAM, a variety of operation circuits, or a like.

The macro cells are supplied with power through a power wiring formed in a wiring region provided outside a macro cell region, in which wiring region is also formed a signal wiring for transmitting a signal between these macro cells.

For example, Japanese Patent Application Laid-open No. 2000-307063 discloses a technology for arranging ring-shaped wiring layers 105 and 106 for supplying power such that ring-shaped wiring layers 105 and 106 surround respectively a macro cell 104 having a multi-layer wiring-construction made up of three wiring layers 101 , 102 , and 103 as shown in FIGS. 13 and 14. These ring-shaped wiring layers 105 and 106 are connected to a power wiring or a ground wiring of at least one of other macro cells and functional blocks which are disposed around the macro cell 104 .

Furthermore, Japanese Patent Application Laid-open No. Hei 09-107070 discloses a technology for providing a ring-shaped diffused layer surrounding a macro cell. In a macro cell 201 having a multi-layer wiring-construction, as shown in FIG. 15, a substrate 202 is mounted thereon with a power wiring for other macro cells and functional blocks, ring-shaped wiring layers 203 and 204 connected to the ground wiring and also mounted therein with a ring-shaped diffused layer 205 below these ring-shaped wiring layers 203 and 204 .

This diffused layer 205 is biased as connected to the ring-shaped wiring layer 203 ( 204 ) connected to no other elements of the macro cell 201 , thus absorbing noise occurring in the macro cell 201 .

As the LSI processes improve in fine patterning and integration density, however, coupling capacitance between adjacent signal lines increases to have a non-negligible adverse effect on the circuit reliability; nevertheless, the above-mentioned conventional technologies have no measures to prevent noise from propagating, for example, between a signal wiring in a macro cell and an adjacent external signal wiring.

Although the above-mentioned technology disclosed in Japanese Patent Application Laid-open No. 2000-307063 can prevent noise on the power wiring or the ground wiring of the macro cell 104 from propagating through the ring-shaped wiring layers 105 and 106 to any other macro cells, functional blocks, or signal wirings disposed around the macro cell 104 , it has a problem that an external signal wiring, if any, adjacent to an internal signal wiring of the macro cell 104 permits the noise to propagate owing to coupling capacitance generated between these wirings, thus causing the malfunctioning of the macro cells or the functional blocks or the retardation and inversion of a signal through the signal wiring.

That is, if a wiring layer 110 of the external signal line of the macro cell 104 is close to its signal line wiring layers 107 , 103 , and 109 at its predetermined position as shown in FIG. 16, coupling capacitance occurs which is proportional to a distance of a parallel going section where, for example, the wiring layer 109 and the wiring layer 110 are close to each other and also which is roughly inversely proportional to a logarithm of a spacing between the two as shown in FIG. 17 .

This coupling capacitance causes noise to propagate between, for example, the wiring layers 109 and 110 to cause useless retardation or mistaken inversion of the signal in a logic circuit 111 a ( 111 b, 111 c, 111 d ) such as shown in FIG. 17, for example, thus having a worse influence as a clock signal frequency becomes larger.

Although the technology disclosed in Japanese Patent Application Laid-Open No. Hei 9-107070, on the other hand, can prevent noise from propagating through the substrate 202 , it still has a problem that the above-mentioned coupling capacitance which occurs between the adjacent signal wirings causes to noise to propagate, thus causing the malfunctioning of the adjacent macro cells or the functional blocks or the retardation or inversion of the signal along the signal wiring.

In view of the above, it is an object of the present invention to provide a high-reliability semiconductor integrated circuit device that can block the propagation of noise that occurs in a macro cell, to thereby prevent the noise from having an adverse effect on the adjacent macro cells, the adjacent functional blocks and adjacent signal wirings.

According to a first aspect of the present invention, there is provided a semiconductor integrated circuit device including:

a functional block in which a plurality of semiconductor elements is formed on a semiconductor substrate and connected with each other by a multi-layer wiring; and

a multi-layer shield portion which is arranged so as to surround the functional block and in which shielding wiring layers are stacked vertically via an inter-layer insulation film,

wherein the multi-layer shield portion is provided with a plurality of via contacts for interconnecting vertically positioned ones of the plurality of shielding wiring layers of the multi-layer shield portion.

In the foregoing, a preferable mode is one wherein the functional block is a macro cell.

A preferable mode is one wherein the via contacts are provided in a circumferential direction of the shielding wiring layers of the multi-layer shield portion with a predetermined spacing therebetween.

A preferable mode is one wherein the via contacts are provided so as to be connected with each other from an uppermost shielding wiring layer to a lowermost shielding wiring layer making up the multi-layer shield portion at an approximately same position as viewed in a plane.

A preferable mode is one wherein the multi-layer shield portion has a notch through which a wiring layer can pass so as to connect to a terminal provided in the functional block.

A preferable mode is one wherein each of the shielding wiring layers of the multi-layer shield portion is formed in a same layer as corresponding one of the multi-layer wirings of the functional block.

A preferable mode is one wherein the multi-layer shield portion is supplied with a predetermined potential but has each of the shielding wiring layers thereof not connected to a power supply terminal or a ground terminal connected to the semiconductor elements formed in the functional block.

A preferable mode is one that wherein further includes a plate-shaped shield portion formed of a plate-shaped shielding wiring layer that covers a top surface of the functional block partially or completely.

A preferable mode is one that wherein the plate-shaped shield portion is supplied with a predetermined potential but not connected to the power supply terminal or the ground terminal connected to the semiconductor elements formed in the functional block.

A preferable mode is one that wherein a tunnel-shaped shield portion is provided in the functional block for accommodating an external wiring layer connected to a circuit outside the functional block in such a manner that the external wiring layer may pass through the functional block along the semiconductor substrate; and

the tunnel-shaped shield portion is provided along a wiring path of the external wiring layer above the external wiring layer, having an upper-part shielding wiring layer consisting of an elongated plate-shaped wiring layer, one pair of side-part shielding wiring layers provided each on two sides of the external wiring layer and arranged parallel to the external wiring layer, and a plurality of via contacts for interconnecting the upper-part shielding wiring layer and each of the side-part shielding wiring layers.

A preferable mode is one that wherein the external wiring layer is arranged in a layer except a lowermost layer on the semiconductor substrate and has below a lower-part shielding wiring layer formed of an elongated plate-shaped wiring layer along a path of the external wiring layer.

A preferable mode is one that wherein the tunnel-shaped shield portion is supplied with a predetermined potential but not connected to the power supply terminal or the ground terminal connected to the semiconductor elements formed in the functional block.

With the above configurations, it is possible to prevent noise from propagating between, for example, two different functional blocks which are adjacent to each other.

That is, noise originated from a wiring layer in a functional block as a signal line is blocked in propagation by the multi-layer shield portion and so prevented from affecting a signal flowing through a wiring layer outside the functional block. Accordingly, it is possible to eliminate such adverse effects of causing the malfunctioning of the functional blocks and a like, or the retardation and inversion of the signal.

In addition, a signal flowing through the wiring layer in the functional block is not influenced by the noise originated from the wiring layer outside the functional block.

The above and other objects, advantages, and features of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a plan view for showing a configuration of a semiconductor integrated circuit device according to a first embodiment of the present invention;

FIG. 2 is a plan view for showing a configuration of a macro cell and a shield portion of the semiconductor integrated circuit device of FIG. 1;

FIG. 3 is an expanded plan view of part A of FIG. 2;

FIG. 4 is a cross-sectional view taken along line B—B of FIG. 3;

FIG. 5 is a cross-sectional view for showing a configuration of a vicinity of a terminal portion of the macro cell;

FIGS. 6A to 6 F are flow diagrams for showing a method for manufacturing the semiconductor integrated circuit device;

FIG. 7 is a plan view for showing a configuration of a macro cell and a shield portion of a semiconductor integrated circuit device according to a second embodiment of the present invention;

FIG. 8 is a cross-sectional view for showing an important part of the macro cell and the shield portion;

FIG. 9 is a cross-sectional view for showing a configuration of an important part of a macro cell and a shield portion of a semiconductor integrated circuit device according to a third embodiment of the present invention;

FIG. 10 is a plan view for showing a configuration of a macro cell and a shield portion of a semiconductor integrated circuit device according to a fourth embodiment of the present invention;

FIG. 11 is a cross-sectional view taken along line C—C of FIG. 10;

FIG. 12 is a cross-sectional view for showing a configuration of an important part of a macro cell and a shield portion of a semiconductor integrated circuit device according to a fifth embodiment of the present invention;

FIG. 13 is an illustration for explaining a conventional technology;

FIG. 14 is an expanded cross-sectional view for explaining the conventional technology taken along line D—D of FIG. 13;

FIG. 15 is an illustration for explaining the conventional technology;

FIG. 16 is another illustration for explaining the conventional technology;

FIG. 17 is a further illustration for explaining the conventional technology.

Best mode of carrying out the present invention will be described in further detail using various embodiments with reference to the accompanying drawings.

First Embodiment

A semiconductor integrated circuit device 1 according to the present embodiment is a semiconductor chip such as a system LSI and, as shown in FIGS. 1 and 2, is arranged in a core region 3 on a substrate (semiconductor substrate) 2 , comprising a plurality of macro cells (functional blocks) 4 having a specific function such as a RAM, a DRAM or a like, a rectangular shield ring (multi-layer shield) 5 disposed so as to surround each macro cell 4 in order to reduce noise occurring therein, and a plurality of input/output circuits 7 disposed in an interface region on the substrate 2 .

The macro cells 4 each have a multi-layer wiring construction having, for example, three wiring layers. That is, as shown in FIGS. 3 and 4, on the substrate 2 is formed a wiring layer 8 a, above which is formed via an inter-layer insulation film 9 a a wiring layer 8 b, above which is in turn formed a wiring layer 8 c via an inter-layer insulation film 9 b. The wiring layers 8 a, 8 b, and 8 c are made of, for example, aluminum and all used as a signal line in the present embodiment.

The shield portion 5 is disposed so as to surround the macro cell 4 with its multi-layer wiring construction having three wiring layers that correspond to the wiring layers of the macro cell 4 . That is, as shown in FIG. 4, on the substrate 2 is formed a wiring layer (shielding wiring layer) 11 a, above which is formed via the inter-layer insulation film 9 a a wiring layer (shielding wiring layer) 11 b, above which is in turn formed a wiring layer (shielding layer) 11 c via the inter-layer insulation film 9 b.

These wiring layers 11 a, 11 b, and 11 c are arranged in the same layers as the wiring layers 8 a, 8 b, and 8 c of the macro cell 4 respectively and formed simultaneously respectively.

As shown in FIGS. 3 and 4, in the inter-layer insulation film 9 a between the wiring layers 11 a and 11 b and the inter-layer insulation film 9 b between the wiring layers 11 b and 11 c are formed via contacts 13 a and 13 b with a predetermined spacing L 0 therebetween to interconnect the wiring layers 11 a and 11 b and the wiring layers 11 b and 11 c respectively.

The via contacts 13 a and 13 b are formed by making an opening in the inter-layer insulation films 9 a and 9 b respectively and filling them with the same conductive material as the wiring layers 11 a, 11 b, and 11 c.

The shield portion 5 is connected to a predetermined potential (for example, the ground potential) but not to a power wiring or a ground wiring in the macro cell 4 .

This configuration makes it possible to hold the wiring layers 11 a, 11 b, and 11 c of the shield portion 5 at roughly the same potential at each site.

In the present embodiment, as shown in FIGS. 3 and 4, at a periphery of the macro cell 4 is present such a position that the wiring layers 8 a, 8 b, and 8 c used as a signal line disposed inside the macro cell 4 and a wiring layer 14 c used as a signal line disposed outside the macro cell 4 run close and parallel to each other in a parallel-going section M having a predetermined length.

Even at such a position that the wiring layer inside the macro cell 4 is near the wiring line outside the macro cell 4 , the shield portion 5 exists between, for example, the wiring layers 8 a, 8 b, and 8 c and the wiring layer 14 c.

Even if noise occurs due to fluctuations in signal level between the wiring layer 8 a ( 8 b, 8 c ) and the wiring layer 14 c running parallel as sandwiching the shield portion 5 , the noise is prevented by the shield portion 5 from propagating so that the wiring layer 8 a ( 8 b, 8 c ) and the wiring layer 14 c may not interfere with each other adversely.

Note here that the wiring layer 14 c is formed at the same time as the wiring layer 8 c of the macro cell 4 and the wiring layer 11 c of the shield portion 5 .

In the present embodiment, as shown in FIG. 5, the substrate 2 has a terminal portion 15 formed thereon for inputting/outputting a signal and also has a wiring layer 16 as a signal line connected to an external circuit of the macro cell 4 formed above the wiring layers 11 c and 14 c via the inter-layer insulation film 9 c. The wiring layer 16 is connected to the terminal portion 15 through via contacts 18 a, 18 b, and 18 c formed in the inter-layer insulation films 9 a, 9 b, and 9 c respectively.

Similarly, wiring layers for the power supply and the ground are also drawn from the upper surface side into the macro cell 4 to be connected to the power supply terminal portion.

The following will describe how to manufacture a semiconductor integrated circuit device according to the present embodiment, in particular, how to form the shield portion.

First, as shown in FIG. 6A, a conductive layer made of such as aluminum or a like is formed on the substrate 2 by sputtering and then processed by photolithography to form the wiring layers 8 a and 11 a.

Next, as shown in FIG. 6B, for example, a silicon nitride film is formed throughout the surface by CVD (Chemical Vapor Depositon) and then, if necessary, etched back to be flattened, thus forming the inter-layer insulation film 9 a.

Next, as shown in FIG. 6C, the inter-layer insulation film 9 a is etched off so as to expose the surface of the wiring layer 11 a, thus forming an opening 12 a. The openings 12 a are arranged in a circumferential direction of the wiring layer 11 a with the predetermined spacing L 0 therebetween.

Next, as shown in FIG. 6D, for example, aluminum is poured into the opening 12 a to provide the via contact 13 a and also patterned to form the wiring layers 8 b and 11 b by photolithography.

Next, as shown in FIG. 6E, for example, a silicon nitride film is formed throughout the surface by CVD and then, if necessary, etched back to be flattened, thus forming the inter-layer insulation film 9 b.

Next, as shown in FIG. 6F, the inter-layer insulation film 9 b is etched to expose the surface of the wiring layer 11 b, thus forming an opening 12 b. The opening 12 b is provided directly above the opening 12 a via the wiring layer 11 b.

Next, for example, aluminum is poured into the opening 12 b to provide the via contact 13 b and also patterned to form the wiring layers 8 c, 11 c, and 14 c by photolithography.

Accordingly, the shield portion 5 is formed having a multi-layer wiring construction comprised of the three wiring layers 11 a, 11 b, and 11 c, which are consecutively connected through the via contacts 13 a and 13 b provided with the predetermined spacing L 0 therebetween.

The following will describe operations of the semiconductor integrated circuit device according to the present embodiment.

As mentioned above, the shield portion 5 has such a multi-layer wiring construction comprised of the three-layered wiring layers 11 a, 11 b, and 11 c as to correspond to that of the macro cell 4 and the via contacts 13 a and 13 b formed therein with the predetermined spacing therebetween and is connected to a predetermined potential (for example, a ground potential) but not connected to a power wiring or a ground wiring provided in the macro cell 4 .

This configuration makes it possible to hold the wiring layers 11 a, 11 b, and 11 c of the shield portion 5 at roughly the same potential.

As shown in FIG. 3, therefore, even at a position where, for example, the wiring layer 8 c provided as an internal signal line of an arbitrary one of the macro cells 4 is close to the wiring layer 14 c provided as an external signal line of the arbitrary one of the macro cells 4 , the shield portion 5 interposed between these two signal lines (wiring layers 8 c and 14 c ) prevents crosstalk noise between two signals on signal lines (wiring layers 8 c and 14 c ) from occuring.

For example, noise originated from any one of the wiring layers 8 c, 8 b, and 8 a as a signal line is prevented by the shield portion 5 from propagating over to the wiring layer 14 c as a signal line.

Accordingly, this noise does not interfere with a signal flowing through the wiring line 14 c.

Thus, with the configuration of this embodiment, as the shield portion 5 is interposed between two signal lines (wiring layers 8 c and 14 c ), it is possible to prevent crosstalk noise between, for example, the macro cell 4 , and adjacent macro cells or adjacent functional blocks.

That is, the shield portion 5 has such a multi-layer wiring construction comprised of the three-layered wiring layers 11 a, 11 b, and 11 c as to correspond to that of the macro cell 4 and the contacts 13 a and 13 b formed therein with the predetermined spacing therebetween and is connected to a predetermined potential (for example, a ground potential) but not connected to a power wiring or a ground wiring provided in the macro cell 4 .

This configuration makes it possible to hold the wiring layers 11 a, 11 b, and 11 c of the shield portion 5 at roughly the same potential.

Accordingly, noise originated from any one of the wiring layers 8 c, 8 b, and 8 a provided as a signal line is blocked by the shield portion 5 in propagation and so does not interfere with a signal flowing through the wiring line 14 c.

This in turn makes it possible to eliminate adverse effects such as the malfunctioning of the macro cells or functional blocks or the retardation or inversion of a signal.

On the other hand, signals flowing through the wiring layers 8 c, 8 b, and 8 a is not affected by a signal flowing through the wiring layer 14 c.

Second Embodiment

The present embodiment greatly differs from the above-mentioned first embodiment in a respect that, as shown in FIGS. 7 and 8, a notch 22 is formed in a shield portion 5 A so as to pass through it a wiring layer as a signal line for connecting to a terminal portion 21 of a macro cell 4 A.

Except this point, the configuration of the present embodiment is roughly the same as that of the above-mentioned first embodiment and its explanation is simplified here.

As shown in FIG. 7, the macro cell 4 A of the present embodiment is formed in a predetermined region on the substrate 2 and has a terminal portion 21 comprised of, for example a plurality of terminals 21 a.

As shown in FIG. 8, a shield portion 5 A has a notch 22 at a site that corresponds to that where the terminal portion 21 is disposed for connection to a circuit outside a macro cell 4 A, through which notch 22 , for example, a wiring layer 23 as a signal line passes to connect to the terminal 21 a.

The wiring layer 23 is formed in the same layer as the terminal portion 21 on the substrate 2 so as to connect to the terminal 21 a.

This configuration of the present embodiment gives almost the same effects as those of the above-mentioned first embodiment.

Besides, the present embodiment eliminates the necessity of forming a wiring layer as a signal line above, for example, the shield portion 5 A, thus improving the wiring efficiency Furthermore, it does not increase the number of processes required.

Third Embodiment

The present embodiment greatly differs from the above-mentioned first embodiment in a respect that, as shown in FIG. 9, a macro cell 4 B is formed above the wiring layers 8 c, 11 c, and 14 c via the inter-layer insulation layer 9 c and has a plate-shaped shield portion 31 covering the macro cell 4 B completely.

Except it, the configuration of the present embodiment is roughly the same as that of the above-mentioned first embodiment and its explanation is omitted here.

This configuration of the present embodiment gives almost the same effects as those of the above-mentioned first embodiment.

Besides, noise occurring in the macro cell 4 B is blocked in propagation by the plate-shaped shield portion 31 and so does not affect a signal flowing through an external wiring layer, if any, disposed above the macro cell 4 B. It is thus possible to securely eliminate adverse effects which cause the malfunctioning of the other macro cells or functional blocks or the retardation or inversion of the signal.

Furthermore, noise coming toward the inside of the macro cell 4 B from the above is blocked in propagation by the plate-shaped shield portion 31 , so that a signal flowing through a wiring layer in the macro cell 4 B is not affected by noise originated from a wiring layer outside the macro cell 4 B.

Fourth Embodiment

The present embodiment greatly differs from the above-mentioned first embodiment in a respect that, as shown in FIG. 10, a macro cell 4 C has a tunnel-shaped shield portion 42 in which a wiring layer connected with an external circuit can pass through the macro cell 4 C along the substrate 2 .

Except this point, the configuration of the present embodiment is roughly the same as that of the above-mentioned first embodiment and so its explanation is simplified here.

As shown in FIG. 11, the tunnel-shaped shield portion 42 has a plurality of wiring layers 43 a disposed parallel with a predetermined spacing therebetween and a wiring layer 43 b formed above these wiring layers 43 a via the inter-layer insulation film 9 a in the same layer as the intermediate wiring layers. The wiring layers 43 a are connected with the wiring layer 43 b through via contacts 45 formed in the inter-layer insulation film 9 a.

The via contacts 45 are disposed in the length direction of the shield portion 42 with a predetermined spacing therebetween (for example, the same as the spacing L 0 of via contacts 13 a, 13 a ).

The wiring layers 43 a and 43 b are held at a predetermined potential (for example, the ground potential).

The wiring layers 43 a and 43 b are not used as another signal line, and connected neither to the power supply nor to the ground in the macro cell 4 C.

The wiring layer 43 b has a width at least larger than the spacing between the wiring layers 43 a.

Above the wiring layer 43 b is formed a wiring layer 43 c, for example, as a signal line via a inter-layer insulation film 9 b.

In the shield portion 42 is formed a wiring layer 41 between the wiring layers 43 a on the substrate 2 . In the present embodiment, the wiring layer 41 is connected to a circuit outside the macro cell 4 C but not to an element or a terminal inside the macro cell 4 C.

As shown in FIG. 10, the shield portion 5 C surrounding the macro cell 4 C has a notch through which the wiring layer 41 passes.

The configuration of the present embodiment gives almost the same effects as those of the above-mentioned first embodiment.

Besides, by the present embodiment, noise is canceled at the interface between the inside and the outside of the macro cell 4 C to thereby permit an external wiring to pass through the macro cell 4 C along a shortest distance without bypassing it, thus improving the degree of freedom in designing.

Fifth Embodiment

The present embodiment greatly differs from the above-mentioned fourth embodiment in a respect that additionally, as shown in FIG. 12, a macro cell 4 D has a plate-shaped shield portion 43 d which is formed above a wiring layer 43 c via a inter-layer insulation film 9 c so as to cover the macro cell 4 D completely.

Except this point, the configuration of the present embodiment is roughly the same as that of the above-mentioned fourth embodiment and so its explanation is omitted here.

This configuration of the present embodiment gives almost the same effects as those of the above-mentioned fourth embodiment.

Besides, by the present embodiment, noise occurring in the macro cell 4 D is blocked in propagation by the plate-shaped shield portion 43 d and so does not affect a signal flowing through a wiring layer outside the macro cell 4 D. It is thus possible to securely eliminate adverse effects which cause the malfunctioning of the other macro cells or functional blocks or the retardation or inversion of the signal.

Furthermore, noise coming toward the inside of the macro cell 4 D from the above is blocked in propagation by the plate-shaped shield portion 43 d, so that a signal flowing through a wiring layer in the macro cell 4 D is not affected by noise originated from a wiring layer outside the macro cell.

It is apparent that the present invention is not limited to the above embodiments but may be changed and modified without departing from the scope and spirit of the invention.

For example, although the above-mentioned embodiments have provided the shield portion so as to surround the macro cell, the present invention may be applied not only to the macro cell but also to a mega-cell or any other functional blocks.

Although the above-mentioned embodiments have set the spacing between the via contacts 13 a ( 13 b ) at a constant value, the spacing may be changed corresponding to, for example, a complexity and a site of the circuits.

Also, the via contacts 13 a and the via contacts 13 b may not always be at the same position but may be different in spacing.

Although the above-mentioned second embodiment has provided a notch in the shield portion 5 A, a shield portion, if provided also on the upper surface side, may have a notch or an opening formed therein so that a signal-wiring layer can pass through it.

Although the above-mentioned fourth embodiment has provided a shield portion that shields an external wiring layer passing through the macro cell, the wiring layer may not pass through the macro cell or may be connected to a terminal or an element in it.

Although the fourth and fifth embodiments have arranged an external wiring layer in the lowermost layer, it may be arranged in an upper layer or step-wise in a plurality of layers.

Furthermore, the conductive material of the wiring layers is not limited to aluminum but may be chromium or copper.