JP5978802B2 - Design support program, design support apparatus, and design support method - Google Patents

Description

  The present invention relates to a design support program, a design support apparatus, and a design support method.

  Conventionally, as a technique for manufacturing a semiconductor device, there is a technique in which a wiring groove is formed on an insulating material, a copper plating is formed on the insulating material after the generation, and a chemical mechanical polishing (CMP) is performed to remove excess copper. is there. For example, there is a technique for designing a dummy pattern so that the difference between the density of the element formation region and the density of the dummy patterns arranged around the element formation region is small (see, for example, Patent Document 1 below).

JP 2002-198419 A

  However, in the above-described prior art, if a region having a relatively low wiring density is unevenly distributed in the circuit, the high region has less copper to be polished, so that polishing of the high region is completed before polishing of the low region is completed. As a result, copper residue may occur in a low region after the CMP is completed.

  An object of the present invention is to provide a design support program, a design support apparatus, and a design support method that can determine whether or not a layout region in which copper residue is likely to occur during manufacturing in order to solve the above-described problems caused by the prior art. And

  In order to solve the above-described problems and achieve the object, according to one aspect of the present invention, the storage content of the storage unit that stores the wiring density of each partial region of the partial region group divided from the layout region of the circuit to be designed For each partial region selected from the partial region group, the wiring density of a predetermined region including a partial region on the layout region and a part or all of the other partial regions continuous with the partial region is calculated and calculated. Based on the wiring density of the predetermined area for each partial area, a value representing the degree of variation in the wiring density of the predetermined area is calculated, and it is determined whether or not the calculated value representing the degree of variation is greater than a predetermined threshold. A design support program, a design support apparatus, and a design support method that output the determined results are proposed.

  According to one aspect of the present invention, there is an effect that it is possible to determine whether or not the layout region is likely to generate copper residue during manufacturing.

FIG. 1 is an explanatory diagram illustrating an operation example of the design support apparatus according to the present embodiment. FIG. 2 is a block diagram illustrating an example of a hardware configuration of the design support apparatus. FIG. 3 is a block diagram illustrating a functional configuration example of the design support apparatus. FIG. 4 is an explanatory diagram showing an example of the contents stored in the mesh information table. FIG. 5 is an explanatory diagram showing an example of the contents stored in the dummy wiring pattern information table. FIG. 6 is an explanatory diagram illustrating an example of calculating the region average density. FIG. 7 is an explanatory diagram showing an example of determining whether or not the layout information is likely to cause copper residue during manufacturing. FIG. 8 is an explanatory diagram illustrating an example of a mesh specified as a correction candidate. FIG. 9 is an explanatory diagram of an example of updating the mesh information table. FIG. 10 is an explanatory diagram illustrating a comparative example of a cross section after manufacturing the layout information in error and a cross section after manufacturing the corrected layout information. FIG. 11 is a flowchart illustrating an example of a design support processing procedure.

  Exemplary embodiments of a disclosed design support program, a design support apparatus, and a design support method will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is an explanatory diagram illustrating an operation example of the design support apparatus according to the present embodiment. The design support apparatus 100 according to the present embodiment is an apparatus that supports layout design. The design support apparatus 100 detects layout information that increases the defect rate of a manufactured semiconductor device. The layout information is information indicating the arrangement of elements in the semiconductor device and the wiring between the elements. The layout information is information according to a format such as GDSII, for example.

  The design support apparatus 100 illustrated in FIG. 1 performs design support for the layout information A and the layout information B. FIG. 1A1 is a plan view of a certain wiring layer in the layout area of the layout information A. FIG. FIG. 1B1 is a plan view of a certain wiring layer in the layout area of the layout information B.

  In the layout information A, a region having a high wiring density and a region having a low wiring density are mixed. In the layout information B, regions with relatively low wiring density are unevenly present. Specifically, in the layout information B, a region having a high wiring density is concentrated in the center, and a region having a low wiring density exists around a region having a high wiring density, as shown in FIGS. In (b1), a region without hatching indicates that the wiring density is low, and a region provided with hatching indicates that the wiring density is high. Further, in FIG. 1 (a1) and FIG. 1 (b1), the layout areas of the layout information A and the layout information B are divided into mesh shapes. Hereinafter, a region divided in a mesh shape is referred to as a “mesh”. The size of the mesh is, for example, 10 to 40 [μm].

  First, for each mesh selected from the mesh group divided from the layout region, the design support apparatus 100 has a wiring density of a predetermined region including a mesh on the layout region and a part or all of another mesh continuous with the mesh. Is calculated. The predetermined area is an area included in a circle whose radius is a unique effective distance for each process. Hereinafter, the wiring density of the predetermined region is referred to as “region average density”. The effective distance is, for example, several hundred to several thousand [μm]. For example, in (a1) of FIG. 1, a predetermined area of the mesh 101A is displayed as a circular area 103A having an effective distance 102A as a radius. Similarly, in (b1) of FIG. 1, a predetermined area of the mesh 101B is displayed as a circular area 103B having an effective distance 102B as a radius.

  Next, the design support apparatus 100 calculates the area average density for each mesh of the layout information A. Since the layout information A includes a region having a high wiring density and a region having a low wiring density, the design support apparatus 100 calculates the region average density for each mesh of the layout information A as a substantially uniform value. Become. Further, the design support apparatus 100 calculates the area average density for each mesh of the layout information B. Since the layout information B is densely populated with regions having a high wiring density, the design support apparatus 100 calculates the region average density for each mesh of the layout information B as a variable value. The reason why the area average density for each mesh of the layout information A becomes a substantially uniform value and the area average density for each mesh of the layout information B varies is shown in (a2) of FIG. 1 and (b2 of FIG. 1). ), (A3) in FIG. 1, and (b3) in FIG.

  FIG. 1A2 is a cross-sectional view of the layout information A at the position Y-Y ′ in FIG. FIG. 1B2 is a cross-sectional view of the layout information B at the position Y-Y ′ in FIG. (A2) in FIG. 1 displays an oxide 111A that is an insulating material and a copper plating 112A. (B2) of FIG. 1 displays the oxide 111B and the copper plating 112B. In the region where the wiring density is high, there are hundreds of wiring grooves. In FIG. 1 (a2) and FIG. 1 (b2), the features of the oxide 111 to the copper plating 112 are shown in a simplified manner. In the region where the wiring density is high, the number of wiring grooves increases, so that the height when the oxide 111 is deposited on the copper plating 112 is low. Further, in the region where the wiring density is low, since the wiring groove is reduced, the height when the oxide 111 is deposited on the copper plating 112 is increased. Further, in a portion where regions having a high wiring density are concentrated as indicated by the region 113, the amount of copper to be polished is small.

  Further, (a3) in FIG. 1 is a diagram modeling the area average density in Y-Y ′ in (a1) in FIG. 1. Further, (b3) in FIG. 1 is a diagram modeling the area average density in Y-Y ′ in (b1) in FIG. 1. As (a3) in FIG. 1 shows, since the layout information A includes a region having a high wiring density and a region having a low wiring density, the region having a high wiring density and the region having a low wiring density cancel each other and vary. The degree becomes smaller. The degree of variation is a difference between values included in the population. The value representing the degree of variation may be standard deviation or variance, for example. Further, as shown in (b3) of FIG. 1, the layout information B has a large variation degree because areas with high wiring density are concentrated in the center.

  Subsequently, the design support apparatus 100 calculates a value representing the degree of variation in the area average density based on the area average density for each mesh. For example, if the value representing the degree of variation is the standard deviation σ, the design support apparatus 100 calculates σ = (1 / nΣ ((region average density−region average density) ^ 2)) ^ 0.5. . Note that n is the total number of meshes. For the layout information A, the design support apparatus 100 calculates that the value indicating the degree of variation is small. When the degree of variation is small, the possibility of copper remaining is small, and the design support apparatus 100 determines that the wiring information need not be corrected for the layout information A. As described above, the design support apparatus 100 according to the present embodiment obtains the degree of bias of the region having a low wiring density by calculating the degree of variation in the region average density.

  For the layout information B, the design support apparatus 100 calculates that the value indicating the degree of variation increases. When the degree of variation is large, there is little copper to be polished in the region where the region average density is high, and the polishing process is completed before the polishing of the low region is completed, and there is a high possibility that the copper residue is generated in the low region. Therefore, the design support apparatus 100 determines that the defect rate of the manufactured semiconductor device is high for the layout information B and it is better to correct the wiring, and outputs the determination result. Next, the design support apparatus 100 according to the present embodiment will be described in detail with reference to FIGS.

(Example of hardware configuration of design support apparatus 100)
FIG. 2 is a block diagram illustrating an example of a hardware configuration of the design support apparatus. 2, the design support apparatus 100 includes a central processing unit (CPU) 201, a read-only memory (ROM) 202, and a random access memory (RAM) 203. The design support apparatus 100 includes a disk drive 204, a disk 205, and a communication interface 206. The design support apparatus 100 includes a display 207, a keyboard 208, and a mouse 209. Further, the CPU 201 to the mouse 209 are respectively connected by a bus 210.

  The CPU 201 is an arithmetic processing unit that controls the entire design support apparatus 100. The ROM 202 is a non-volatile memory that stores a program such as a boot program. A RAM 203 is a volatile memory used as a work area for the CPU 201.

  The disk drive 204 is a control device that controls reading and writing of data with respect to the disk 205 according to the control of the CPU 201. As the disk drive 204, for example, a magnetic disk drive, an optical disk drive, a solid state drive, or the like can be adopted. The disk 205 is a non-volatile memory that stores data written under the control of the disk drive 204. For example, when the disk drive 204 is a magnetic disk drive, a magnetic disk can be adopted as the disk 205. Further, when the disk drive 204 is an optical disk drive, an optical disk can be adopted as the disk 205. When the disk drive 204 is a solid state drive, a semiconductor element memory can be adopted for the disk 205.

  The communication interface 206 is a control device that controls an internal interface with the network 211 and controls input / output of data from an external device. Specifically, the communication interface 206 is connected to a local area network (LAN), a wide area network (WAN), the Internet, or the like that is the network 211 through a communication line, and is connected to other devices via the network 211. For example, a modem or a LAN adapter may be employed as the communication interface 206.

  The display 207 is a device that displays data such as a cursor, an icon, or a tool box, as well as data such as a document, an image, and function information. As the display 207, for example, a Cathode Ray Tube (CRT), a Thin Film Transistor (TFT) liquid crystal display, a plasma display, or the like can be employed.

  The keyboard 208 is a device that has keys for inputting characters, numbers, various instructions, and the like and inputs data. The keyboard 208 may be a touch panel type input pad or a numeric keypad. The mouse 209 is a device for moving a cursor, selecting a range, moving a window, changing a size, and the like. The mouse 209 may be a trackball or a joystick as long as it has the same function as a pointing device.

(Functional configuration of design support apparatus 100)
Next, a functional configuration example of the design support apparatus 100 will be described. FIG. 3 is a block diagram illustrating a functional configuration example of the design support apparatus. The design support apparatus 100 includes a first calculation unit 301, a second calculation unit 302, a determination unit 303, an extraction unit 304, an identification unit 305, an output unit 306, a third calculation unit 307, and an update unit 308. And including. The first calculation unit 301 to the update unit 308 serving as the control unit realize the functions of the first calculation unit 301 to the update unit 308 when the CPU 201 executes a program stored in the storage device. Specifically, the storage device is, for example, the ROM 202, the RAM 203, the disk 205, etc. shown in FIG. Alternatively, the functions of the first calculation unit 301 to the update unit 308 may be realized by another CPU executing via the communication interface 206.

  Further, the design support apparatus 100 can access the mesh information table 311 and the dummy wiring pattern information table 312. The mesh information table 311 and the dummy wiring pattern information table 312 are stored in a storage device such as the RAM 203 and the disk 205. The mesh information table 311 stores the wiring density of each mesh of the mesh group divided from the layout area of the layout information. Details of the mesh information table 311 will be described later with reference to FIG. Further, the dummy wiring pattern information table 312 stores dummy wiring pattern information that is the area of the dummy wiring. Further, the dummy wiring pattern information may store a dummy wiring arrangement position and a dummy wiring shape in a unit area. Details of the dummy wiring pattern information table 312 will be described later with reference to FIG.

  The first calculation unit 301 refers to the mesh information table 311, and for each mesh selected from the mesh group, a region average including a part of or all of the meshes on the layout region and other meshes that are continuous with the meshes described above. Calculate the density. The mesh selected from the mesh group may be the entire layout region or a part thereof. For example, the first calculation unit 301 calculates the wiring density using the mesh 101, eight meshes around the mesh 101, and a part of the 16 meshes around the eight meshes as predetermined regions. The average area density may be an average value in a predetermined area, a median value, or an average value obtained by weighting the center mesh.

  In addition, the first calculation unit 301 may calculate the area average density for each mesh selected from the mesh group with reference to the stored content of the updated mesh information table 311 updated by the update unit 308. . The calculated area average density for each mesh may be stored in a storage area such as the RAM 203 and the disk 205 in addition to being recorded in the mesh information table 311.

  The second calculation unit 302 calculates a value representing the degree of variation in the region average density based on the region average density for each mesh calculated by the first calculation unit 301. The degree of variation may be, for example, standard deviation or variance. The calculated degree of variation is stored in a storage area such as the RAM 203 or the disk 205.

  The determination unit 303 determines whether or not the value representing the degree of variation calculated by the second calculation unit 302 is greater than a predetermined threshold value. The predetermined threshold value is a process-specific value and is set by a designer. The predetermined threshold value is stored in advance in a storage area such as the RAM 203 and the disk 205. For example, if the predetermined threshold is 500 [μm] and the standard deviation that is a value representing the degree of variation is 700 [μm], the determination unit 303 determines that the degree of variation is greater than the predetermined threshold. Note that the determination result is stored in a storage area such as the RAM 203 or the disk 205.

  The extraction unit 304 extracts a predetermined number of meshes from the meshes selected from the mesh group in descending order of the area average density for each mesh calculated by the first calculation unit 301. The predetermined number may be, for example, the number of 40 [%] of the number of meshes selected from the mesh group, or may be half of the number. The predetermined number is a value unique to the process and is designated in advance by the designer. The predetermined number is stored in advance in a storage area such as the RAM 203 and the disk 205. For example, the extraction unit 304 extracts half of the number of meshes selected from the mesh group in ascending order of area average density. The extracted mesh identification information is stored in a storage area such as the RAM 203 and the disk 205.

  The specifying unit 305 specifies a predetermined number of meshes smaller than the predetermined number among the predetermined number of meshes extracted by the extracting unit 304 in order from the lowest wiring density for each mesh. For example, it is assumed that there are 100 × 100 = 10000 meshes in the layout information, and the extraction unit 304 extracts half of 5000 meshes. At this time, the specifying unit 305 specifies 10 meshes out of 5000 meshes in order from the lowest wiring density. The identified mesh identification information is stored in a storage area such as the RAM 203 and the disk 205.

  The output unit 306 outputs the determination result determined by the determination unit 303. For example, the output unit 306 outputs that the degree of variation in the area average density of the layout information is small and that the possibility of copper residue is low. Further, the output unit 306 outputs that the degree of variation in the area average density of the layout information is large and that there is a high possibility that copper residue will occur.

  The output unit 306 may output the extraction result extracted by the extraction unit 304 when the determination unit 303 determines that the value indicating the degree of variation is larger than the threshold value. For example, the output unit 306 determines the number of meshes selected from the mesh group in order of increasing area average density when there is a high degree of variation in the area average density of the layout information and there is a high possibility of copper residue. The identification information of half of the meshes is output.

  The output unit 306 may output the specifying result specified by the specifying unit 305 when the determining unit 303 determines that the value indicating the degree of variation is larger than the threshold value. For example, the output unit 306, when the degree of variation in the area average density of the layout information is large and there is a high possibility of copper remaining, the 10 meshes of the 5000 meshes from the lowest in the order of the wiring density. Output identification information. The output format includes, for example, display on the display 207 and transmission to an external device through the communication interface 206. The output data may be stored in a storage area such as the RAM 203 or the disk 205.

If the third calculation unit 307 determines that the value representing the degree of variation calculated by the first calculation unit 301 is greater than the threshold value, the third calculation unit 307 applies the specified mesh based on the area of the dummy wiring that is unrelated to the transmission of the electrical signal. The wiring density of the mesh when the dummy wiring is arranged is calculated. For example, it is assumed that the wiring density of the specified mesh is 30 [%] and the area of the specific mesh is 100 [μm ² ]. At this time, when the dummy wiring having an area of 10 [μm ² ] is arranged, the third calculation unit 307 sets the wiring density of the mesh when the dummy wiring is arranged as (100 × 0.3 + 10) / 100 = 40. Calculate as [%]. The third calculation unit 307 may calculate the wiring density of the mesh by arranging a dummy wiring pattern. A specific calculation formula for arranging the dummy wiring pattern will be described later with reference to FIG.

  The update unit 308 updates the wiring density of the mesh specified by the specifying unit 305 stored in the mesh information table 311 to the mesh wiring density calculated by the third calculation unit 307.

  FIG. 4 is an explanatory diagram showing an example of the contents stored in the mesh information table. The mesh information table 311 is a table that stores information for each mesh. The mesh information table 311 illustrated in FIG. 4 stores records 401-1 to 401-3. The mesh information table 311 includes seven fields of wiring layer IDentification (ID), x coordinate, y coordinate, copper density, dummy copper density, area average density, and dummy change information.

  In the wiring layer ID field, a number for uniquely specifying the wiring layer of the layout information is stored. The x coordinate field stores the x coordinate of the target mesh in the target wiring layer. The y coordinate field stores the y coordinate of the target mesh in the target wiring layer. In the copper density field, the wiring density of the target mesh is stored. The dummy copper density field stores the wiring density of the dummy wiring pattern among the copper densities. The area average density field stores the area average density of the target mesh. In the dummy change information field, an identifier indicating whether a dummy wiring pattern has been arranged for the target mesh portion is stored. Specifically, the dummy change information field stores “0” when a dummy wiring pattern is not arranged, and stores a dummy wiring pattern ID arranged when a dummy wiring pattern is arranged. The dummy wiring pattern ID will be described later with reference to FIG.

  For example, the record 401-1 indicates information of a mesh in which the first wiring layer has an x coordinate of X1 [μm] and a y coordinate of Y1 [μm]. Hereinafter, the mesh at the designated x-coordinate and y-coordinate positions is expressed as mesh (x, y). Specifically, in the record 401-1, the copper density of the corresponding mesh is 40 [%], the dummy copper density is 15 [%], the area average density is 44 [%], and the dummy wiring is arranged. Indicates that it has not been.

  FIG. 5 is an explanatory diagram showing an example of the contents stored in the dummy wiring pattern information table. FIG. 5A shows an example of the contents stored in the dummy wiring pattern information table 312. FIG. 5B illustrates a record 501-1 stored in the dummy wiring pattern information table 312 as an example of dummy wiring pattern information. FIG. 5C illustrates a record 501-2 stored in the dummy wiring pattern information table 312 as another example of dummy wiring pattern information. In FIG. 5B and FIG. 5C, the dummy wirings arranged in a certain predetermined range are hatched.

  The dummy wiring pattern information table 312 is a table that stores the positions and shapes of dummy wirings arranged within a unit area for each dummy wiring pattern information. The dummy wiring pattern information table 312 illustrated in FIG. 5 stores records 501-1 and 501-2.

  The dummy wiring pattern information table 312 includes seven fields of dummy wiring pattern ID, x-direction size, y-direction size, interval, shape, offset, and copper density. In the dummy wiring pattern ID field, dummy wiring pattern identification information is stored. The x direction size field stores the size of the dummy wiring in the x direction. The y direction size field stores the size of the dummy wiring in the y direction. In the interval field, the interval of the dummy wiring is stored. In the shape field, an identifier indicating the shape of the dummy wiring is stored. The offset field stores the position from the origin of the unit area to a certain point in the dummy wiring when the dummy wiring is arranged. The origin may be an arbitrary position within the unit area. In the copper density field, the copper density in the corresponding dummy wiring pattern is stored. The value of the copper density can be calculated from the x-direction size, the y-direction size, the interval, the shape, and the offset. FIG. 5B illustrates the lengths indicated by the x-direction size, the y-direction size, the interval, and the offset.

  For example, the record 501-1 indicates dummy wiring pattern information whose dummy wiring pattern ID is 1. Specifically, the record 501-1 includes dummy wiring pattern information in which the dummy wiring pattern ID is 1, the dummy wiring size is 3 [μm] in the x direction, and 3 [μm] in the y direction. It shows that the shape of the dummy wiring is a square. Further, in the record 501-1, the dummy wiring pattern information in which the dummy wiring pattern ID is 1 indicates that the dummy wiring interval is 5 [μm], the dummy wiring offset is 2 [μm], and the copper density is 40. [%].

  FIG. 6 is an explanatory diagram illustrating an example of calculating the region average density. In FIG. 6A to FIG. 6C, the wiring density is expressed by the color density. FIG. 6A shows the layout area 601. FIG. 6A shows the difference in wiring density by the difference in hatch. Specifically, a region having a high wiring density is represented by a dark hatch, and a region having a low wiring density is represented by a thin hatch. In the layout area 601, the wiring density in the peripheral area is high, and the wiring density in the central area is low.

  Next, FIG. 6B shows a state in which the layout area 601 is divided into meshes. After dividing the area average density, the design support apparatus 100 calculates the area average density of each mesh. For example, the design support apparatus 100 calculates the area average density of the mesh 602. As the area average density, an average value of copper densities of meshes included in the predetermined area may be used, or an average value obtained by weighting a Gaussian distribution according to the distance from the center mesh may be used. FIG. 6C is a diagram in which the area average density of each mesh is expressed by the color density. It shows that the area average density is higher as the color is closer to black.

  FIG. 7 is an explanatory diagram showing an example of determining whether or not the layout information is likely to cause copper residue during manufacturing. A graph 701 shown in FIG. 7 shows the distribution of the area average density of each mesh for the layout information A and the layout information B. The horizontal axis of the graph 701 indicates the area average density. The vertical axis of the graph 701 indicates the appearance probability.

For example, the average area density of each mesh in the layout information A is 62.5 [%], and is scattered from 35 [%] to 70 [%]. The design support apparatus 100 calculates the standard deviation σ _A of the area average density of the layout information A. The value indicated by the standard deviation σ _{A of the} calculated area average density is, for example, the range shown on the graph 701. μ _A indicates an average value of the area average density of each mesh of the layout information A.

Next, the design support apparatus 100 determines whether or not the standard deviation σ _A of the area average density is greater than a predetermined threshold value. The predetermined threshold is a value unique to each process, and is, for example, 5 to 10 [%]. In the example of FIG. 7, the design support apparatus 100 determines that the standard deviation σ _A of the area average density is larger than a predetermined threshold value. Since the standard deviation σ _A of the area average density is larger than the predetermined threshold value, the design support apparatus 100 determines that there is a high possibility that copper residue will occur in the layout information A. Hereinafter, layout information that is highly likely to have copper residue is referred to as “layout information in error”.

The area average density of each mesh in the layout information B is the largest at 47.5 [%] and is accumulated in the vicinity of 47.5 [%]. The design support apparatus 100 calculates the standard deviation σ _B of the area average density of the layout information B. The value indicated by the standard deviation σ _{B of the} calculated area average density is, for example, the range shown on the graph 701. μ _B indicates an average value of the area average density of each mesh of the layout information B. As shown by graph 701 above, mu _B is smaller than mu _A.

Next, the design support apparatus 100 determines whether or not the standard deviation σ _B of the area average density is greater than a predetermined threshold value. In the example of FIG. 7, the design support apparatus 100 determines that the standard deviation σ _B of the area average density is equal to or less than a predetermined threshold value. Since the standard deviation σ _B of the area average density is equal to or less than the predetermined threshold, the design support apparatus 100 determines that there is a low possibility that copper residue will occur in the layout information B.

  Subsequently, the design support apparatus 100 specifies a mesh that is a candidate for setting a dummy wiring pattern so that the height difference is low with respect to the layout information A that is an error. An example of the extracted mesh will be described with reference to FIG.

  FIG. 8 is an explanatory diagram illustrating an example of a mesh specified as a correction candidate. FIG. 8A shows an example in which the identified mesh is output. 8 (b1) to 8 (b3) show the position of the identified mesh on the layout information in error, and also show how the layout information A in error is being polished. ing.

  The design support apparatus 100 outputs, to the error list 801, meshes whose area average density is equal to or lower than the average value in order of increasing copper density among the meshes. More specifically, the design support apparatus 100 outputs, to the error list 801, the meshes that are the lower 20% of the copper density among the meshes and that the area average density is equal to or less than the average value in ascending order of the copper density. May be.

  The error list 801 shown in FIG. 8A stores records 801-1 to 801-3. The error list 801 includes four fields: wiring layer ID, x coordinate, y coordinate, and copper density. The definition of each field in the error list 801 is the same as the definition of the field having the same name in the mesh information table 311, and thus description thereof is omitted. For example, records 801-1 to 801-3 indicate information on meshes (X1, Y1) to meshes (X3, Y1) having a small copper density among meshes having a region average density equal to or lower than the average value.

  (B1) of FIG. 8 shows a cross-sectional view at y = Y1 after the generation of the copper plating of the layout information A in error. In FIG. 8B1, since the variation degree of the area average density is large, the height difference of the layout information when the copper plating 812 is deposited on the oxide 811 is large. Further, the mesh (X1, Y1) to mesh (X3, Y1) have a slightly large difference in height. Note that the mesh group located in the direction where x of the mesh (X1, Y1) is small has a large difference in height, but there are a lot of thin wiring grooves and a large copper density, resulting in an error list. In 801, the identification information of the corresponding mesh is not output.

  Next, (b2) of FIG. 8 shows a state in which the barrier metal (BRM) applied to the surface of the oxide 811 is detected during polishing in the polishing process. The copper polishing is terminated when the sensor attached to the polishing pad detects BRM. At this time, the amount of copper to be polished is small in the region 813 of (b1) in FIG. 8 and (b2) in FIG. Therefore, the stress concentrates on the copper in the region 813 and the polishing is accelerated, and the time for detecting the BRM is accelerated.

  Subsequently, (b3) in FIG. 8 shows a state where overpolishing is performed after detection of BRM in the polishing step. (B3) of FIG. 8 shows a state in which overpolishing is insufficient and a copper residue is generated in the region 814. When the copper residue is generated, a short circuit is caused, so that the semiconductor device including the region 814 is a defective product.

  FIG. 9 is an explanatory diagram of an example of updating the mesh information table. FIG. 9A shows an example of updating the mesh information table 311 when dummy wiring is arranged. 9 (b1) to FIG. 9 (b3) show the positions of the meshes where the dummy wiring patterns are arranged on the layout information in error, and the layout information where the dummy arrangement patterns are arranged is polished. It shows how it is being done.

  The design support apparatus 100 arranges dummy wirings on the mesh at the top of the error list 801 among the meshes output from the error list 801. The design support apparatus 100 calculates a value to be set in the dummy copper density field after placement using the following equation (1).

  Dummy copper density after placement = Dummy copper density before placement × (copper density of dummy wiring pattern after placement / copper density of dummy wiring pattern before placement) (1)

  Moreover, the design support apparatus 100 calculates the copper density after arrangement using the following equation (2).

  Copper density after placement = (copper density before placement-dummy copper density before placement) + dummy copper density after placement (2)

  For example, it is assumed that the design support apparatus 100 arranges a dummy wiring whose dummy wiring pattern ID is “1” on the mesh (X1, Y1). Further, it is assumed that a dummy wiring pattern having a copper density of 30 [%] is set in advance in the mesh (X1, Y1). In this case, the design support apparatus 100 calculates the dummy copper density after arranging the dummy wiring pattern in the mesh (X1, Y1) by the equation (1).

  Dummy copper density after placement = 15 × (40/30) = 20 [%]

  In addition, the design support apparatus 100 calculates the copper density after placing the dummy wiring pattern by the equation (2).

  Copper density after placement = (40−15) + 20 = 45 [%]

  The design support apparatus 100 updates the copper density field and dummy copper density field of the record 401-1 corresponding to the mesh (X1, Y1) with the calculated copper density after placement and dummy copper density after placement. The design support apparatus 100 updates the dummy change information field of the record 401-1 with the ID “1” of the dummy wiring pattern to be arranged. Similarly, the design support apparatus 100 arranges the dummy wiring pattern having the dummy wiring pattern ID “2” on the mesh (X2, Y1), and records the copper density field, dummy copper density field, and dummy change information of the record 401-2. Update the field. Subsequently, the design support apparatus 100 calculates the area average density of each mesh and updates the area average density of the corresponding record 401.

  (B1) of FIG. 9 is after copper plating generation when the dummy wiring pattern ID “1” is arranged in the mesh (X1, Y1) and the dummy wiring pattern ID “2” is arranged in the mesh (X2, Y1). Shows the state. By arranging the dummy wiring, the height difference of the layout information when the copper plating 902 is deposited on the oxide 901 becomes smaller than that in FIG.

  Next, (b2) of FIG. 9 shows a state in which BRM applied to the surface of the oxide 901 is detected during polishing in the polishing step. In the region 903 in FIG. 9B1, the stress applied to the copper in the region 903 is reduced by the amount of the difference in height. Therefore, when the sensor detects BRM in the region 903, the copper is sufficiently polished in the other regions.

  Subsequently, (b3) of FIG. 9 shows a state where overpolishing is performed after detection of BRM in the polishing step. In (b3) of FIG. 9, overpolishing is sufficiently performed and there is no portion that causes a short circuit. Thus, the design support apparatus 100 can improve the yield during manufacturing by arranging the dummy wiring pattern. Next, a cross-sectional view of the layout information shown in FIGS. 8 and 9 will be described.

  FIG. 10 is an explanatory diagram illustrating a comparative example of a cross section after manufacturing the layout information in error and a cross section after manufacturing the corrected layout information. FIG. 10A shows a cross section of the circuit to be designed in error. Next, (b1) of FIG. 10 displays a cross section of the chip after manufacturing the layout information when the optimization by the area average density in the present embodiment is performed. Next, (c1) in FIG. 10 displays the area average density of each mesh when the optimization by the area average density shown in (b1) of FIG. 10 is performed. As shown in (c1) of FIG. 10, the variation degree of the area average density of each mesh in the layout information optimized by the area average density is reduced, and there is no error.

  Subsequently, (b2) of FIG. 10 displays a cross section of the chip after manufacturing the layout information when the optimization by the area average density is not performed. The optimization performed in (b2) of FIG. 10 is, for example, optimization that improves flatness within each mesh. Next, (c2) in FIG. 10 displays the area average density of each mesh when optimization by area average density is not performed. As shown in (c2) of FIG. 10, the variation degree of the area average density of each mesh of the layout information that has not been optimized by the area average density becomes large, resulting in an error. Next, a flowchart for executing the operation described with reference to FIGS. 3 to 10 will be described with reference to FIG.

  FIG. 11 is a flowchart illustrating an example of a design support processing procedure. The design support processing procedure is a process for determining whether or not the layout information is likely to cause a copper residue during manufacturing. The design support apparatus 100 generates mesh information from the layout information and stores it in the mesh information table 311 (step S1101). Specifically, the design support apparatus 100 generates mesh information by dividing a layout region into a mesh shape from layout information and obtaining a copper density included in the corresponding mesh.

  Next, the design support apparatus 100 selects the lowermost wiring layer among the wiring layers (step S1102). Subsequently, the design support apparatus 100 acquires mesh information of the selected wiring layer (step S1103). Next, the design support apparatus 100 calculates the area average density of the area specified by the effective distance unique to the process for each mesh (step S1104). Subsequently, the design support apparatus 100 calculates the degree of variation in the area average density of each mesh (step S1105). Next, the design support apparatus 100 determines whether or not the degree of variation is greater than a predetermined threshold unique to the process (step S1106).

  If larger (step S1106: Yes), the design support apparatus 100 extracts a mesh whose area average density is equal to or lower than the average value (step S1107). Next, the design support apparatus 100 specifies a predetermined number of meshes among the extracted meshes in order from the lowest copper density (step S1108). Next, the design support apparatus 100 calculates the wiring density when a dummy wiring pattern that increases the copper density is arranged on the identified mesh (step S1109). Subsequently, the design support apparatus 100 updates the mesh information table 311 with the calculated wiring density (step S1110). After the end of step S1110, the design support apparatus 100 proceeds to the process of step S1104.

  When the degree of variation is equal to or less than a predetermined threshold unique to the process (step S1106: No), the design support apparatus 100 determines whether all wiring layers have been selected (step S1111). If there is a wiring layer that has not yet been selected (step S1111: No), the design support apparatus 100 selects the next wiring layer (step S1112). After completing the execution of step S1112, the design support apparatus 100 proceeds to the process of step S1103.

  When all the wiring layers are selected (step S1111: Yes), the design support apparatus 100 outputs the degree of variation for all the wiring layers and the mesh information in which the dummy change information is updated (step S1113). After the end of step S1113, the design support apparatus 100 ends the design support process. By executing the design support processing, the design support apparatus 100 determines whether or not the layout information is likely to generate copper residue during manufacturing, and if it is likely to occur, the mesh information table is used to improve the yield. 311 can be updated.

  As described above, according to the design support apparatus 100, the area average density that is the wiring density for each predetermined area that partially overlaps between adjacent areas in the layout information is obtained, and the degree of variation in the wiring density of the entire layout information is determined. to decide. As a result, the design support apparatus 100 can determine the degree of variation of the entire circuit while ignoring local variations, and can specify layout information in which copper residue is likely to occur. In addition, when it is determined not the area average density but the degree of variation of the divided areas, the copper remaining area including the low wiring density area and the high wiring density area as shown in the layout information A of FIG. There is also a possibility that layout information that is unlikely to be generated may be judged to have a high copper residue. In this case, dummy wiring arrangement processing that is not necessary is performed.

  In addition, the design support apparatus 100 can improve the determination accuracy of the design support process by reducing the mesh. In addition, the design support apparatus 100 can increase the processing speed of the design support process by increasing the mesh. Further, if this embodiment is not carried out and further overpolishing is performed, a control load is applied, and copper in the wiring trench is further polished to make the wiring thinner and increase the wiring resistance. there is a possibility.

  Further, according to the design support apparatus 100, when the degree of variation is large, a predetermined number of partial areas may be output in the order of low area average density. As a result, the designer can acquire information on meshes that are candidates for correction when correcting the circuit to be designed so as not to generate copper residue.

  Further, according to the design support apparatus 100, when the degree of variation is large, the number smaller than the specific predetermined number in the descending order of the wiring density among the specific predetermined number of partial areas extracted from the order in which the area average density is low. A partial area may be specified and the specified partial area may be output. As a result, when the designer corrects the design target circuit so as not to generate a copper residue, the designer can acquire information on a mesh having a low wiring density and easy to correct. In addition, since the mesh with high wiring density has few places which can insert dummy wiring, it is difficult for a designer to correct the mesh with high wiring density.

  Further, according to the design support apparatus 100, when the degree of variation is large, the wiring density when dummy wiring is arranged in the specified partial region may be calculated, and the mesh information table 311 may be updated. Thereby, the designer can arrange the dummy wiring pattern so as to match the updated copper density and correct the design target circuit.

  Further, the design support apparatus 100 may determine whether or not the degree of variation in the mesh area average density is large with reference to the stored contents of the updated mesh information table 311. As a result, if the degree of variation in the circuit to be designed after correction is small, the possibility of copper residue being generated can be reduced. Therefore, the design support apparatus 100 can increase the yield of semiconductor devices manufactured using the circuit to be designed. Can be improved.

  Moreover, according to the design support apparatus 100, since an experiment using a test chip and a simulation tool are not used, it is possible to improve the yield while suppressing costs and time costs.

  The design support method described in this embodiment can be realized by executing a program prepared in advance on a computer such as a personal computer or a workstation. The design support program is recorded on a computer-readable recording medium such as a hard disk, a flexible disk, a CD-ROM, an MO, and a DVD, and is executed by being read from the recording medium by the computer. The design support program may be distributed via a network such as the Internet.

  The following additional notes are disclosed with respect to the embodiment described above.

(Supplementary note 1)
With reference to the storage content of the storage unit that stores the wiring density of each partial region of the partial region group divided from the layout region of the circuit to be designed, for each partial region selected from the partial region group, on the layout region Calculating a wiring density of a predetermined region including a part or all of the partial region and another partial region continuous with the partial region,
Based on the calculated wiring density of the predetermined area for each partial area, a value representing the degree of variation in the wiring density of the predetermined area is calculated,
Determining whether the calculated value representing the degree of variation is greater than a predetermined threshold;
Output the result of the decision
A design support program characterized by causing processing to be executed.

(Supplementary note 2)
Extracting a predetermined number of partial areas out of the partial areas selected from the partial area group, in ascending order of wiring density of the predetermined areas for the calculated partial areas,
When it is determined that the calculated value representing the degree of variation is greater than the threshold value, the extracted extraction result is output.
The design support program according to appendix 1, wherein the process is executed.

(Supplementary note 3)
From the descending order of wiring density for each partial area, out of the predetermined number of extracted partial areas, a process for specifying a predetermined number of partial areas smaller than the predetermined number is executed,
The output process is as follows:
The design support program according to appendix 2, wherein when the calculated value representing the degree of variation is determined to be greater than the threshold value, the specified specific result is output.

(Supplementary note 4)
When it is determined that the calculated value representing the degree of variation is greater than the threshold value, the portion when the dummy wiring is arranged in the specified partial region based on the area of the dummy wiring unrelated to transmission of an electric signal Calculate the wiring density of the area,
Update the wiring density of the specified partial area stored in the storage unit to the calculated wiring density of the partial area,
The design support program according to appendix 3, wherein the process is executed.

(Additional remark 5) The process which calculates the wiring density of the said predetermined area | region is
The design support according to appendix 4, wherein the wiring density of the predetermined region is calculated for each partial region selected from the partial region group with reference to the updated storage content of the storage unit program.

(Supplementary Note 6) For each partial region selected from the partial region group with reference to the storage content of the storage unit that stores the wiring density of each partial region of the partial region group divided from the layout region of the design target circuit, Calculating a wiring density of a predetermined region including a part or all of the partial region and the other partial region continuous with the partial region on the layout region;
Based on the calculated wiring density of the predetermined area for each partial area, a value representing the degree of variation in the wiring density of the predetermined area is calculated,
Determining whether the calculated value representing the degree of variation is greater than a predetermined threshold;
Output the result of the decision
A recording medium on which a design support program for causing a computer to execute processing is recorded.

(Supplementary Note 7) With reference to the storage content of the storage unit that stores the wiring density of each partial region of the partial region group divided from the layout region of the design target circuit, for each partial region selected from the partial region group, A first calculation unit that calculates a wiring density of a predetermined region including a part or all of the partial region and the other partial region continuous with the partial region on the layout region;
A second calculation unit that calculates a value representing a variation degree of the wiring density of the predetermined region based on the wiring density of the predetermined region for each of the partial regions calculated by the first calculation unit;
A determination unit that determines whether or not a value representing the degree of variation calculated by the second calculation unit is greater than a predetermined threshold;
An output unit for outputting a determination result determined by the determination unit;
A design support apparatus comprising:

(Supplementary Note 8) For each partial region selected from the partial region group with reference to the storage content of the storage unit that stores the wiring density of each partial region of the partial region group divided from the layout region of the design target circuit, A first calculation unit that calculates a wiring density of a predetermined region including a part or all of the partial region and the other partial region continuous with the partial region on the layout region;
A second calculation unit that calculates a value representing a variation degree of the wiring density of the predetermined region based on the wiring density of the predetermined region for each of the partial regions calculated by the first calculation unit;
A determination unit that determines whether or not a value representing the degree of variation calculated by the second calculation unit is greater than a predetermined threshold;
An output unit for outputting a determination result determined by the determination unit;
A design support apparatus including a computer having

(Supplementary note 9)
With reference to the storage content of the storage unit that stores the wiring density of each partial region of the partial region group divided from the layout region of the circuit to be designed, for each partial region selected from the partial region group, on the layout region Calculating a wiring density of a predetermined region including a part or all of the partial region and another partial region continuous with the partial region,
Based on the calculated wiring density of the predetermined area for each partial area, a value representing the degree of variation in the wiring density of the predetermined area is calculated,
Determining whether the calculated value representing the degree of variation is greater than a predetermined threshold;
Output the result of the decision
A design support method characterized by executing processing.

DESCRIPTION OF SYMBOLS 100 Design support apparatus 301 1st calculation part 302 2nd calculation part 303 Judgment part 304 Extraction part 305 Specification part 306 Output part 307 3rd calculation part 308 Update part

Claims (7)

On the computer,
With reference to the storage content of the storage unit that stores the wiring density of each partial region of the partial region group divided from the layout region of the circuit to be designed, for each partial region selected from the partial region group, on the layout region Calculating a wiring density of a predetermined region including a part or all of the partial region and another partial region continuous with the partial region,
Based on the calculated wiring density of the predetermined area for each partial area, a value representing the degree of variation in the wiring density of the predetermined area is calculated,
By determining that the calculated value representing the degree of variation is greater than a predetermined threshold, it is determined that copper residue is likely to occur during the manufacture of the design target circuit,
Output the result of the decision
A design support program characterized by causing processing to be executed. In the computer,
Extracting a predetermined number of partial areas out of the partial areas selected from the partial area group, in ascending order of wiring density of the predetermined areas for the calculated partial areas,
When it is determined that the calculated value representing the degree of variation is greater than the threshold value, the extracted extraction result is output.
The design support program according to claim 1, wherein processing is executed. In the computer,
From the descending order of wiring density for each partial area, out of the predetermined number of extracted partial areas, a process for specifying a predetermined number of partial areas smaller than the predetermined number is executed,
The output process is as follows:
3. The design support program according to claim 2, wherein when the calculated value representing the degree of variation is determined to be larger than the threshold value, the specified specific result is output. In the computer,
When it is determined that the calculated value representing the degree of variation is greater than the threshold value, the portion when the dummy wiring is arranged in the specified partial region based on the area of the dummy wiring unrelated to transmission of an electric signal Calculate the wiring density of the area,
Update the wiring density of the specified partial area stored in the storage unit to the calculated wiring density of the partial area,
The design support program according to claim 3, wherein processing is executed. The process of calculating the wiring density of the predetermined area is as follows:
The design according to claim 4, wherein the wiring density of the predetermined region is calculated for each partial region selected from the partial region group with reference to the updated storage content of the storage unit. Support program. With reference to the storage content of the storage unit that stores the wiring density of each partial region of the partial region group divided from the layout region of the circuit to be designed, for each partial region selected from the partial region group, on the layout region A first calculation unit that calculates a wiring density of a predetermined region including a part or all of the partial region and another partial region continuous with the partial region;
A second calculation unit that calculates a value representing a variation degree of the wiring density of the predetermined region based on the wiring density of the predetermined region for each of the partial regions calculated by the first calculation unit;
A determination unit value representing the degree of variation calculated by said second calculation section by determining the greater than a predetermined threshold, for determining that tends copper residue occurs at the time of manufacture of the design target circuit,
An output unit for outputting a determination result determined by the determination unit;
A design support apparatus comprising: Computer
With reference to the storage content of the storage unit that stores the wiring density of each partial region of the partial region group divided from the layout region of the circuit to be designed, for each partial region selected from the partial region group, on the layout region Calculating a wiring density of a predetermined region including a part or all of the partial region and another partial region continuous with the partial region,
Based on the calculated wiring density of the predetermined area for each partial area, a value representing the degree of variation in the wiring density of the predetermined area is calculated,
By determining that the calculated value representing the degree of variation is greater than a predetermined threshold, it is determined that copper residue is likely to occur during the manufacture of the design target circuit,
Output the result of the decision
A design support method characterized by executing processing.

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