The present application claims priority from Japanese patent application No. 2007-207425 filed on Aug. 9, 2007, the content of which is hereby incorporated by reference into this application.
The present invention relates to a wiring technology of electrically coupling wirings of wiring layers adjacent to each other of a semiconductor device using vias.
In the manufacturing process of a semiconductor device, vias have been additionally inserted for coupling wirings of different wiring layers, for example, in order to prevent the yield of the semiconductor device from decreasing due to a random defect by fine particles, a photomask alignment error, or the like.
In Patent Document 1 (Specification of U.S. Pat. No. 5,798,937), a technology of disposing a via and then adding redundant vias next to it is described. In Patent Document 2 (Specification of U.S. Pat. No. 6,026,224), a technology of additionally arranging vias on grids adjacent to and around certain one via is described. The technologies described in the documents are those of additionally arranging redundant vias in addition to a specific via.
In Patent Document 3 (Japanese Unexamined Patent Publication No. 2005-347692), a technology of coupling wirings inclined 45 degrees to each other with vias is described and in particular the structure of a via referred to as a double-cut via is shown. The double-cut via has a via structure formed by performing wiring extension or the like in consideration of the states of wirings around a first via and/or the states of other vias to provide a second via in addition to the first via. The via structure is also formed by a technology of arranging redundant vias in addition to a specific via. Also in Patent Document 4 (Japanese Unexamined Patent Publication No. 2005-109336), a design method of providing redundant vias in addition to the specific via to couple wirings inclined 45 degrees to each other is shown as in Patent Document 3.
The present inventors have examined problems in multiplexing vias. Firstly, it has been found out that when wiring is performed on a cell basis, in the case that a plurality of via cells of single vias is arranged to multiplex vias, it must be determined every time each of the via cells is arranged whether spatial conditions are satisfied for the surroundings, and the data processing time becomes longer as the number of multiplexed vias increases. Secondly, when a plurality of vias is arranged linearly along wiring grids, spatial conditions in the arrangement directions are different from those in directions crossing the arrangement directions, which causes nonuniformity of wirability in each of the X-direction and the Y-direction. Thirdly, a rule related to a space between different potential vias which is an interval between vias connected to different potential signal lines is severer than the rule of a minimum pitch of wirings, so that when a plurality of vias is arranged corresponding to intersections of grids respectively, there is a restriction that different potential vias cannot be arranged without being separated at least two grids from the surroundings. These problems are not considered in any of the patent documents. When adopting a design approach of providing redundant vias in addition to a specific via for coupling wirings of different wiring layers to each other, any of the problems cannot be solved.
An object of the present invention is to multiplex vias to shorten the data processing time for wiring connection.
Another object of the present invention is to provide via multiplexing technology which can contribute to high density wiring.
Still another object of the present invention is to provide via multiplexing technology which can contribute to a higher degree of integration of circuit elements.
Still another object of the present invention is to make a restriction to the layout of different potential vias not become severe, the restriction being given to the surroundings of vias by multiplexing the vias.
The above and further objects and novel features of the present invention will be apparent from the following description of this specification and the accompanying drawings.
The outline of a typical one of inventions disclosed in this application will be briefly described below.
For coupling wirings of different wiring layers, a multiple via cell section is used which has vias for electrically coupling wirings bent in an L-shape of different wiring layers on both sides with the L-shaped bent portion therebetween. The vias of the multiple via cell section are on a grid line in an X-direction and a grid line in a Y-direction defined with a minimum wiring pitch, and all or part of the vias of the multiple via cell section are deviated from intersections of grid lines in the X-direction and grid lines in the Y-direction.
The vias of the multiple via cell section are placed on each of the grid line in the X-direction and the grid line in the Y-direction, corresponding to the L-shape, so that there is not much difference between the spatial conditions in the X-direction and the spatial conditions in the Y-direction viewed from the multiple via cell section. This is different from the case that when a plurality of vias is arranged linearly along a wiring grid, spatial conditions for the arrangement direction are much different from spatial conditions for the direction crossing the arrangement direction. Thus, wirability in the X-direction becomes equivalent to that in the Y-direction. The equivalency in wirability results in the equivalency also in layout restriction points for the different potential vias around the multiple via cell section in each of the X-direction and the Y-direction, thus reducing the number of vias to which the restriction is applied. Furthermore, the vias of the multiple via cell section are on grid lines but are deviated from the intersection of the grid lines, so that the cover margins of the vias, that is, the margins allowing deviations of the vias even if the vias are deviated in the wiring directions, substantially increase by the deviations from the intersection, because of relations to the spatial conditions for the surroundings of the vias. This can contribute to high integration of a semiconductor device. Furthermore, each of the multiple via cell sections has a plurality of vias, so that when the multiple via cells are used, the time of the wiring processing can be reduced as compared with data processing of multiplexing vias by adding vias around specific vias in the wiring processing.
Effects obtained by a typical one of inventions disclosed in this application will be briefly described below.
The invention can multiplex vias to shorten the data processing time for wiring connection.
The invention can contribute to higher density wiring.
The invention can contribute to high integration of circuit elements.
The invention can multiplex vias so that a restriction to the layout of different potential vias to the surroundings does not become severe.
First, the outline of typical embodiments of the present invention disclosed in this application will be described. Reference numerals and symbols in figures referred with parentheses in the outline description about the typical embodiments indicate only examples included in concepts of components to which the reference numerals and symbols are attached.
[1—1] A semiconductor device has: many circuit cell sections (2, 3, 4, CEL) which are regularly arranged over a semiconductor substrate; terminals (Ts, L11, L12) of the arranged circuit cell sections formed in a first wiring layer; and a plurality of via cell sections of a first hierarchy for coupling the terminals of the circuit cell sections to a second wiring layer over the first wiring layer. The semiconductor device includes, as the via cell section of the first hierarchy, a first multiple via cell section (20) having vias (32, 33) for electrically coupling wirings (30, 31) bent in an L-shape of wiring layers adjacent to each other on both sides with the L-shaped bent portion therebetween. The vias of the first multiple via cell section are on a grid line in an X-direction and a grid line in a Y-direction defined with a minimum wiring pitch, and all or part of the vias of the first multiple via cell section are deviated from an intersection of the grid line extending in the X-direction and the grid line in the Y-direction. The circuit cell sections and the via cell sections mean circuit portions constituted in correspondence with cells (defined based on cell data) to be arranged in cell-based wiring design. Thus, the first multiple via cell sections mean circuit portions constituted in correspondence with a first multiple via cell which is one of cell data.
The vias of the first multiple via cell section are placed on each of the grid line in the X-direction and the grid line in the Y-direction, corresponding to the L-shape, so that there is not much difference between spatial conditions in the X-direction and spatial conditions in the Y-direction viewed from the first multiple via cell section. This is different from the case that when a plurality of vias is arranged linearly along a wiring grid, spatial conditions in an arrangement direction are much different from spatial conditions in a direction crossing the arrangement direction. Thus, according to the above means, wirability in the X-direction becomes equivalent to that in the Y-direction. The equivalency in wirability results in the equivalency also in layout restriction points for the different potential vias around the first multiple via cell section in each of the X-direction and the Y-direction, thus reducing the number of vias to which the restriction is applied. Furthermore, the vias of the first multiple via cell section are on grid lines but are deviated from the intersection of the grid lines, so that the cover margins of the vias, that is, the margins allowing deviations of the vias even if the vias are deviated in the wiring directions, substantially increase by the deviations from the intersection, because of relations to the spatial conditions for the surroundings of the vias.
[1—2] The semiconductor device of item 1—1 further includes, as the via cell section of the first hierarchy, a second multiple via cell section (40) having a plurality of vias (43, 44) linearly-arranged for electrically coupling wirings (41, 42) of respective wiring layers adjacent to each other extending linearly with insulating layers therebetween. The respective vias of the second multiple via cell section are on a grid line defined with a minimum wiring pitch, and all or part of the vias of the second multiple via cell section are deviated from an intersection of the grid lines. When the first multiple via cell section cannot be used, also in the case that the second multiple via cell section is used, the cover margins of the vias substantially increase by the deviations from the intersection, because of the relations to the spatial conditions for the surroundings of the vias.
[1—3] when the semiconductor device of item 1—1 further includes a plurality of via cell sections of a second hierarchy for coupling wirings of the second wiring layer to wirings of a third wiring layer, the first multiple via cell section may be adopted as the via cell section of the second hierarchy.
[1—4] When the semiconductor device of item 1—3 further includes a plurality of via cell sections of a third hierarchy for coupling wirings of the third wiring layer to wirings of a fourth wiring layer, the first multiple via cell section may be adopted as the via cell section of the third hierarchy.
[2—1] A semiconductor device has: many circuit cell sections regularly arranged over a semiconductor substrate; terminals of the arranged circuit cell sections formed in a first wiring layer; a plurality of via cell sections of a first hierarchy for coupling the terminals of the circuit cell sections to a second wiring layer over the first wiring layer; and a plurality of via cell sections of a second hierarchy for coupling wirings of the second wiring layer to wirings of a third wiring layer. The semiconductor device includes, as the via cell sections of the first and second hierarchies, a first multiple via cell section including vias for electrically coupling wirings bent in an L-shape of wiring layers adjacent to each other on both sides with the L-shaped bent portion therebetween. The via cell sections of the first hierarchy include the first multiple via cell sections more than the via cell sections of the second hierarchy.
The vias of the first multiple via cell section can be coupled to wirings in the X-direction and wirings in the Y-direction on both sides of the L-shaped bent portion, so that there is not much difference between spatial conditions in the X-direction and spatial conditions in the Y-direction viewed from the first multiple via cell section. This is different from the case that when a plurality of vias is arranged linearly along a wiring grid, spatial conditions in an arrangement direction are much different from spatial conditions in a direction crossing the arrangement direction. Thus, the wirability in the X-direction can be made equivalent to that in the Y-direction. In short, it becomes easy to form other wirings in both of the X-direction and the Y-direction around the first multiple via cell section. Furthermore, the equivalency in wirability around the first multiple via cell section means that it becomes easy to multiplex vias in regions of high wiring density. The wirings of the first wiring layer in which terminals of the circuit cell sections are formed have a higher wiring density than the wirings of other wiring layers. For this reason, by adopting a large number of the first multiple via cell sections with a high priority in such a region, multiplexing of vias is promoted throughout the semiconductor device, thereby contributing to the increase of the yield of the semiconductor device.
[2—2] The semiconductor device of item 2—1 further includes a plurality of via cell sections of a third hierarchy for coupling wirings of the third wiring layer to wirings of a fourth wiring layer. When the semiconductor device includes, as the via cell sections of the third hierarchy, the first multiple via cell sections, the via cell sections of the first hierarchy include the first multiple via cell sections more than the via cell sections of the second hierarchy. It is assumed that the wiring density lowers in the upper layer. In regions of high wiring density, the first multiple via cell section allows multiplexing of vias also in narrow places, and in regions of low wiring density, the first multiple via cell section acts to increase the wiring flexibility in the surrounding regions.
[2—3] The semiconductor device of item 2—2 further includes, as the via cell sections of the first hierarchy, the second multiple via cell sections each having a plurality of vias arranged linearly for electrically coupling wirings of wiring layers adjacent to each other extending linearly with insulating layers therebetween. Even if the first multiple via cell sections L-shaped as the spatial conditions cannot be adopted, adopting linearly-arranged second multiple via cell sections can contribute to the increase of the yield of the semiconductor device.
[2—4] The semiconductor device of item 2—3 further includes, as the via cell sections of the second hierarchy, the second multiple via cell sections. Also for the via cell sections of the second hierarchy, the same thing as item 2—2 can be applied.
[2—5] The semiconductor device of item 2—4 further includes, as the via cell sections of the third hierarchy, the second multiple via cell sections. Also for the via cell sections of the third hierarchy, the same thing as item 2—2 can be applied.
[2—6] Each of the vias is formed by filling a conductive via plug coupled to wirings of the respective upper and lower wiring layers into a via hole penetrating an insulating layer between the upper and lower wiring layers.
[3—1] A wiring method for a semiconductor device includes the process of, when using a computer to arrange circuit cells necessary for constituting required circuits and then to couple wiring patterns to the arranged circuit cells, arranging a first multiple via cell including vias for electrically coupling wiring patterns bent in an L-shape of different wiring layers on both sides with the L-shaped bent portion therebetween, at points for coupling wiring patterns of different wiring layers. According to this method, each of the first multiple via cell sections has a plurality of vias, so that when the first multiple via cells are used, the time of the wiring processing can be reduced as compared with data processing of adding and-multiplexing vias around specific vias in the wiring processing.
[3—2] In the wiring method of item 3—1, when the first multiple via cell is arranged, the vias of the first multiple via cell section are placed on a grid line in an X-direction and a grid line in a Y-direction defined with a minimum wiring pitch, and all or part of the vias of the first multiple via cell section are deviated from an intersection of the grid line in the X-direction and the grid line in the Y-direction. Line segments coupling centers of vias constituting the first multiple via cell to each other are slanted against the grid line in the X-direction and the grid line in the Y-direction, and the distance between the centers has been previously defined, so that the above operation can be performed. It is not required that vias are arranged at the intersection of grid lines. Each of the vias only has to be placed on a grid line.
According to the above description, the vias of the first multiple via cell section are placed on each of the grid line in the X-direction and the grid line extending in the Y-direction, corresponding to the L-shape, so that there is not much difference between spatial conditions in the X-direction and spatial conditions in the Y-direction viewed from the first multiple via cell section. This is different from the case that when the vias are arranged linearly along a wiring grid, spatial conditions in an arrangement direction are much different from spatial conditions in a direction crossing the arrangement direction. Thus, the wirability in the X-direction becomes equivalent to that in the Y-direction. The equivalency in wirability results in the equivalency also in layout restriction points for the different potential vias around the first multiple via cell section in each of the X-direction and the Y-direction, thus reducing the number of vias to which the restriction is applied. Furthermore, the vias of the first multiple via cell section are on grid lines but are deviated from the intersection of the grid lines, so that the cover margins of the vias, that is, the margins allowing deviations of the vias even if the vias are deviated in the wiring directions, substantially increase by the deviations from the intersection, because of relations to the spatial conditions for the surroundings of the vias. This can contribute to the high integration of a semiconductor device.
[3—3] The wiring method of item 3—2 performs the following processing as one concrete processing when using a computer to arrange circuit cells necessary for constituting required circuits and then to couple wiring patterns to the arranged circuit cells. The concrete processing includes the processes of: reading data of the first multiple via cell including the vias for electrically coupling wiring patterns bent in an L-shape of different wiring layers on both sides with the L-shaped bent portion therebetween; and arranging the first multiple via cell using the data at points for coupling wiring patterns of different wiring layers.
It is also possible to use first multiple via cells at all connection points between wiring layers from the start. In this case, the effect of increase of the yield can be expected most, but high integration of the semiconductor device is sacrificed to some extent.
[3—4] <<Single Via Cells are Selectively Replaced with First Multiple Via Cells>>
The wiring method of item 3—2 performs the following processing as another concrete processing when using a computer to arrange circuit cells necessary for constituting required circuits and then to couple wiring patterns to the arranged circuit cells. The concrete processing includes the processes of: reading data of the first multiple via cell including the vias for electrically coupling wiring patterns bent in an L-shape of different wiring layers on both sides with the L-shaped bent portion therebetween; reading data of single via cells for electrically coupling wiring patterns of different wiring layers using single vias; arranging the single via cells using the data at points for coupling wiring patterns of different wiring layers; determining whether or not a spatial conditions necessary for replacing the single via cells with first multiple via cells is satisfied around the arranged single via cells; and rearranging the first multiple via cells using the data instead of single via cells at points determined to satisfy the spatial conditions.
As a result, at first, single via cells are used at connection points between wiring layers, so that vias for coupling the lowest wiring layer of high wiring density including wiring patterns in circuit cells to the upper wiring layer can be initially arranged at a high density, and in this point, the highest priority may be given to a request for high integration of the semiconductor device. In this condition, replacing the single via cells with first multiple via cells within a possible range can contribute to the increase of the yield of the semiconductor device.
[3—5] <<Single Via Cells are Forcibly Replaced with First Multiplex Via Cells>>
The wiring method of item 3—2 performs the following processing as another concrete processing when using a computer to arrange circuit cells necessary for constituting required circuits and then to couple wiring patterns to the arranged circuit cells. The concrete processing includes the processes of: reading data of the first multiple via cell including the vias for electrically coupling wiring patterns bent in an L-shape of different wiring layers on both sides with the L-shaped bent portion therebetween; reading data of single via cells for electrically coupling wiring patterns of different wiring layers using single vias; arranging the single via cells using the data at points for coupling wiring patterns of different wiring layers; rearranging the first multiple via cells using the data instead of the arranged single via cells; and allowing wiring patters around the first multiple via cells to satisfy the spatial conditions when the rearranged first multiple via cells do not satisfy the spatial conditions between the first multiple via cells and the surroundings.
As a result, at first, single via cells are used at connection points between wiring layers, so that vias for coupling the lowest wiring layer of high wiring density including wiring patterns in circuit cells to the upper wiring layer can be initially arranged at a high density, and in this point, the highest priority may be given to a request for high integration of the semiconductor device. In this condition, forcibly replacing the single via cells with first multiple via cells can achieve the increase of the yield of the semiconductor device more than the means of item 3—4. However, time for correcting the wiring patterns is needed.
[3—6] <<Single Via Cells are Selectively Replaced with Second Multiple Via Cells, and Single Via Cells Which Cannot be Replaced with Second Multiple Via Cells are Forcibly Replaced with First Multiple Via Cells>>
The wiring method of item 3—2 performs the following processing as still another concrete processing when using a computer to arrange circuit cells necessary for constituting required circuits and then to couple wiring patterns to the arranged circuit cells. The concrete processing includes the processes of: reading data of the first multiple via cell including the vias for electrically coupling wiring patterns bent in an L-shape of different wiring layers on both sides with the L-shaped bent portion therebetween; reading data of second multiple via cells for electrically coupling wiring patterns of different wiring layers extending linearly using a plurality of vias arranged linearly in parallel; reading data of single via cells for electrically coupling wiring patterns of different wiring layers using single vias; arranging the single via cells using the data at points for coupling wiring patterns of different wiring layers; determining whether or not a spatial conditions necessary for replacing the single via cells with second multiple via cells is satisfied around the arranged single via cells; rearranging the second multiple via cells using the data instead of single via cells at points determined to satisfy the spatial conditions; rearranging the first multiple via cells using the data instead of single via cells at points determined not to satisfy the spatial conditions; and allowing wiring patters around the first multiple via cells to satisfy the spatial conditions when the rearranged first multiple via cells do not satisfy the spatial conditions between the first multiple via cells and the surroundings.
As a result, at first, single via cells are used at connection points between wiring layers, so that vias for coupling the lowest wiring layer of high wiring density including wiring patterns in circuit cells to the upper wiring layer can be initially arranged at a high density, and in this point, the highest priority may be given to a request for high integration of the semiconductor device. In this condition, replacing single via cells with second multiple via cells within a possible range and forcibly replacing the remaining single via cells with first multiple via cells can achieve the increase of the yield of the semiconductor device more than the means of item 3—4. However, time for correcting the wiring patterns is needed but less than that in item 3—5.
[3—7] <<Single Via Cells are Selectively Replaced with First Multiple Via Cells, and Single Via Cells Which Cannot be Replaced with First Multiple Via Cells are Forcibly Replaced with Second Multiple Via Cells>>
The wiring method of item 3—2 performs the following processing as still another concrete processing when using a computer to arrange circuit cells necessary for constituting required circuits and then to couple wiring patterns to the arranged circuit cells. The concrete processing includes the processes of: reading data of the first multiple via cell including the vias for electrically coupling wiring patterns bent in an L-shape of different wiring layers on both sides with the L-shaped bent portion therebetween; reading data of second multiple via cells for electrically coupling wiring patterns of different wiring layers extending linearly using a plurality of vias arranged linearly in parallel; reading data of single via cells for electrically coupling wiring patterns of different wiring layers using single vias; arranging the single via cells using the data at points for coupling wiring patterns of different wiring layers; determining whether or not a spatial conditions necessary for replacing the single via cells with first multiple via cells is satisfied around the arranged single via cells; rearranging the first multiple via cells using the data instead of single via cells at points determined to satisfy the spatial conditions; rearranging the second multiple via cells using the data instead of single via cells at points determined not to satisfy the spatial conditions; and allowing wiring patters around the second multiple via cells to satisfy the spatial conditions when the rearranged second multiple via cells do not satisfy the spatial conditions between the second multiple via cells and the surroundings.
As a result, at first, single via cells are used at connection points between wiring layers, so that vias for coupling the lowest wiring layer of high wiring density including wiring patterns in circuit cells to the upper wiring layer can be initially arranged at a high density, and in this point, the highest priority may be given to a request for high integration of the semiconductor device. In this condition, replacing single via cells with first multiple via cells within a possible range and forcibly replacing the remaining single via cells with second multiple via cells can achieve the increase of the yield of the semiconductor device more than the means of item 3—4. However, time for correcting the wiring patterns is needed but less than that in item 3—6, because, as described above, in regions of high wiring density, first multiple via cells enables multiplexing of vias also in narrow places, and in regions of low wiring density, first multiple via cells act to increase the wiring flexibility in the surrounding regions, so that the number of single via cells which cannot be replaced with the first multiple via cells and are remained is reduced and consequently the correction points of wiring patterns caused by forcibly replacing the single via cells with the second multiple via cells are reduced.
[4—1] A data processing system supporting wiring design for a semiconductor device includes a data processor executing a program and a storage device. The data processor, when arranging circuit cells necessary for constituting required circuits and then coupling wiring patterns to the arranged circuit cells, performs the process of arranging first multiple via cells including vias for electrically coupling wiring patterns bent in an L-shape of different wiring layers on both sides with the L-shaped bent portion therebetween, at points for coupling wiring patterns of different wiring layers. According to this processing, each of the first multiple via cells has the vias, so that when the first multiple via cells are used, the time of the wiring processing can be reduced as compared with data processing of adding and multiplexing vias around specific vias in the wiring processing.
[4—2] In the data processing system of item 4—1, when the first multiple via cells are arranged, the vias of the first multiple via cell sections are placed on a grid line in an X-direction and a grid line in a Y-direction defined with a minimum wiring pitch, and all or part of the vias of the first multiple via cell section are deviated from an intersection of the grid line in the X-direction and the grid line in the Y-direction. Thus, the wirability in the X-direction becomes equivalent to that in the Y-direction. The equivalency in wirability results in the equivalency also in layout restriction points for the different potential vias around the first multiple via cell section in each of the X-direction and the Y-direction, thus reducing the number of vias to which the restriction is applied. Furthermore, the vias of the first multiple via cell section are on grid lines but are deviated from the intersection of the grid lines, so that the cover margins of the vias, that is, the margins allowing deviations of the vias even if the vias are deviated in the wiring directions, substantially increase by the deviations from the intersection, because of relations to the spatial conditions for the surroundings of the vias. This can contribute to high integration of a semiconductor device.
[4—3] In the data processing system of item 4—2, the data processor may performs processing of item 3—3, item 3—4, item 3—5, item 3—6, or item 3—7, when arranging circuit cells necessary for constituting required circuits and coupling wiring patterns to the arranged circuit cells.
The embodiments will be described in more detail.
<<Semiconductor Device>>
The circuit cell section (CEL) 5 is a circuit portion specified by circuit cell data used for a cell-based layout design (wiring design), and terminals T such as the signal terminals and the power system terminals of the circuit cell section (CEL) 5 are allocated as wirings L11 and L12 of the first wiring layer M1. Shapes of wirings in circuit portions defined by circuit cell data do not become objects of changes in principle in the layout design. Thus, the wiring patterns of the wirings L11 and L12 which are terminals of the cell are not objects of shape changes in the layout design.
For the wirings SL, VL, and GL for coupling the terminals of the circuit cell, wirings of the wiring layers M2, M3, and M4 over the wiring layer M1 are used. Wirings of wiring layers which are different from one another are coupled by via cell sections.
The vias of the first multiple via cell section 20 are placed on each of the grid line GRD_X in the X-direction and the grid line GRD_Y in the Y-direction, corresponding to the L-shape, so that there is not much difference between the spatial conditions in the X-direction and the spatial conditions in the Y-direction viewed from the first multiple via cell section 20. In other words, the ends of the wirings L13, L14, and L15 of the first wiring layer M1 are separated from the wiring 30 of the first multiple via cell section 20 so as to keep the minimum wiring interval therebetween. The ends of the wirings L23, L24, and L25 of the second wiring layer M2 are separated from the wiring 31 of the first multiple via cell section 20 to keep the minimum wiring interval therebetween. Thus, the size of space SPC1 left for the wirings of first wiring layer M1 with respect to the first multiple via cell section 20 is substantially equal to the size of space SPC2 left for the wirings of second wiring layer M2 with respect to the first multiple via cell section 20.
When the second multiple via cell section 40 in which vias are arranged in series along a wiring grid is adopted as illustrated in
<<Data Processing System>>
The circuit cell database 76 has the names of circuit cells and pattern graphic data constituting the circuit cells.
The via cell database 77 has the names of via cells and pattern graphic data constituting the via cells. For example, as illustrated in
Graphic data of circuit cells and via cells and graphic data of examples and pattern information have, for example, a data structure of polygon data or path data (symbolic data) shown in
The layout processing program 73 is executed by the data processor 70 to control the following wiring method for a semiconductor device.
<<Wiring method>>
In the layout design S4, layout and wiring are performed on a cell basis. For example, the layout design S4 includes floor plan creation processing (S4A), automatic layout of circuit cells and physical pattern generation processing (S4B) corresponding thereto, and the subsequent automatic layout processing of multiple via cells (S4C). Here, in the automatic layout of circuit cells and physical pattern generation processing (S4B) corresponding to the layout, single via cells are used for connections between wirings of different wiring layers. In the processing S4C, the processing of replacing single via cells with multiple via cells is performed. When the automatic layout processing of multiple via cells S4C has come to cause wirings short-circuited or layout rule violation such as wiring pitch violation, the processing of correcting physical patterns is performed.
<<Single Via Cells are Selectively Replaced with First Multiple Via Cells>>
Since first multiple via cells each have a plurality of vias 32 and 33, when the first multiple via cells are used, the time of the wiring processing can be reduced as compared with data processing of multiplexing single vias by adding other single vias around specific single vias in the wiring processing.
Furthermore, at first, single via cells are used at connection points between wiring layers, so that vias for coupling the lowest wiring layer of high wiring density including wiring patterns in circuit cells to the upper wiring layer can be initially arranged at a high density, and in this point, the highest priority may be given to a request for high integration of the semiconductor device. In this condition, replacing single via cells with first multiple via cells within a possible range can contribute to increase of the yield of the semiconductor device.
When the processing of
<<Single Via Cells are Forcibly Replaced with First Multiple Via Cells>>
After that, it is determined whether the spatial conditions are satisfied at points where single via cells have been forcibly replaced with first multiple via cells (S50), wirings which are short-circuited or do not satisfy the minimum space at points where the spatial conditions are not satisfied are cut off (S51), and the cut portions are coupled to wirings of other wiring layers or are detoured using other wirings of the same wiring layer (S52), in order that the spatial conditions are satisfied in the surroundings of the first multiple via cells for which the spatial conditions are not satisfied. When finishing the series of processing, the data processor 70 outputs a message of the effect (S44).
As a result, at first, single via cells are used at connection points between wiring layers, so that vias for coupling the lowest wiring layer of high wiring density including wiring patterns in circuit cells to the upper wiring layer can be initially arranged at a high density, and in this point, the highest priority may be given to a request for high integration of the semiconductor device. In this condition, forcibly replacing single via cells with first multiple via cells can achieve increase of the yield of the semiconductor device more than the case of
<<First Multiple Via Cells are Arranged from the Start>>
When the first multiple via cells are used at all connection points between wiring layers from the start, the effect of increase of the yield can be expected most, but high integration of the semiconductor device is sacrificed to some extent.
<<Initially Arranged Single Via Cells are Replaced with Second Multiple Via Cells and then Remaining Via Cells are Forcibly Replaced with First Multiple Via Cells>>
In the processing of S70, the data processor 70 extracts points where single via cells can be replaced with second multiple via cells on the basis of read information. In other words, the data processor 70 determines whether the spatial conditions necessary to replace single via cells at the points with second multiple via cells are satisfied around the single via cells. The spatial conditions include a condition that the wiring is not short-circuited with any other wiring, a condition that the minimum interval is kept between the wiring and any other wiring, a condition that a sufficient interval is kept between the vias and adjacent different potential vias, and the like. When the spatial conditions are satisfied, the cell names of corresponding single via cells are changed to cell names of second multiple via cells, and patterns are generated to rearrange second multiple via cells at the positions of the single via cells using the cell data of the second multiple via cells. The data processor 70 performs the above processing for all of single via cells at extracted locations.
In the subsequent processing of S71, the cell names of single via cells which have been determined not to satisfy the spatial conditions and are remained are unconditionally changed to cell names of first multiple via cells, and patterns are generated to forcibly rearrange first multiple via cells at the positions of the single via cells using the cell data of the first multiple via cells. “Forcibly” means that it doesn't matter whether the spatial conditions are satisfied in the surroundings. The above processing is performed for all of the extracted single via cells. After that, it is determined whether the spatial conditions are satisfied at points where single via cells have been forcibly replaced with first multiple via cells, wirings which are short-circuited or do not satisfy the minimum space at points where the spatial conditions are not satisfied are cut off, and the cut portions are coupled to wirings of other wiring layers or are detoured using other wirings of the same wiring layer, in order that the spatial conditions are satisfied in the surroundings of the first multiple via cells for which the spatial conditions are not satisfied. When finishing the series of processing, the data processor 70 outputs a message of the effect (S44).
As a result, at first, single via cells are used at connection points between wiring layers, so that vias for coupling the lowest wiring layer of high wiring density including wiring patterns in circuit cells to the upper wiring layer can be initially arranged at a high density, and in this point, the highest priority may be given to a request for high integration of the semiconductor device. In this condition, replacing single via cells with second multiple via cells within a possible range and forcibly replacing the remaining single via cells with first multiple via cells can achieve increase of the yield of the semiconductor device more than the case of
<<Initially Arranged Single Via Cells are Replaced with First Multiple Via Cells and then Remaining Via Cells are Forcibly Replaced with Second Multiple Via Cells>>
As a result, at first, single via cells are used at connection points between wiring layers, so that vias for coupling the lowest wiring layer at high wiring density including wiring patterns in circuit cells to the upper wiring layer can be initially arranged at a high density, and in this point, the highest priority may be given to a request for high integration of the semiconductor device. In this condition, replacing single via cells with first multiple via cells within a possible range and forcibly replacing the remaining single via cells with second multiple via cells can achieve increase of the yield of the semiconductor device more than the case of
Up to this point, the present invention developed by the present inventor has been concretely described based on the embodiments. However, it is needless to say that the present invention is not limited to the embodiments and various changes and modifications can be made without departing from the spirit and scope of the present invention.
For example, the number of vias provided in a first or second multiple via cell is not limited to two and may be three or more. Only part of vias of a first multiple via cell may be deviated from the intersection of the grid line in the X-direction and the grid line in the Y-direction.
Number | Date | Country | Kind |
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2007-207425 | Aug 2007 | JP | national |