[0024] See figure 1 , The method of inserting filling graphics in the territory of this application includes the following steps:
[0025] The first step is to read the layout data, for example, read in the layout data in GDSII format in a binary format. Different production processes define the number of local areas included in a layout and the size of each local area. According to the layout data, find the structure that allows the insertion of filled graphics in each local area.
[0026] There are many layers on a silicon wafer manufactured with semiconductor devices, and only a small part of the layers need to be inserted into the filling pattern to meet the requirements of the CMP process. For this small part of the hierarchy, the process rules determine which blank parts are allowed to insert filled graphics, and which blank parts are not allowed. For other levels, some levels are forbidden to insert other levels of filling graphics. Through the calculation of the entire layout data, the mutual influence and restriction between the various layers can be analyzed, so as to find the structure that allows the insertion of filling graphics in each local area.
[0027] The second step is to virtually insert the standard filling figure A in the structure that allows the insertion of the filling figure in each local area. Different production processes have defined their own standard filling patterns, and the standard filling patterns are unique in shape and size, generally rectangular. Usually in the structure that allows the insertion of filled graphics, the insertion is performed in the form of an array of standard fill graphics A, but it must not exceed the range of the structure that allows the insertion of fill graphics, and it must cater to the outline of the structure that allows the insertion of fill graphics .
[0028] The third step is to calculate the graphic density DYi=(X+Y)/Z of the local area after the filling graphic is virtually inserted. Among them, Dyi is the figure density value of the local area, and the unit is a percentage. X is the area occupied by the original graphics of the local area. Y is the area occupied by the filled graphics inserted in the local area. Z is the area of the local area.
[0029] It is judged whether the graphic density DYi of the partial area after inserting the filled graphic is greater than or equal to the minimum requirement DYS of the graphic density of the partial area.
[0030] If it is, it means that the graphic density of the local area after the filling graphic has been inserted has met the minimum requirement, so it is only necessary to actually insert the filling graphic in the structure of the local area that allows the insertion of the filling graphic.
[0031] If not, it means that the graphic density of the local area after inserting the filled graphic does not meet the minimum requirements, so the filled graphic needs to be replaced with a new filled graphic, and then step 4.
[0032] In the fourth step, in the structure of the partial area that allows the insertion of filling graphics, a new filling graphic that is larger than the previous virtual insertion is inserted virtually. Repeat steps 3 to 4 until the graphic density DYi of the local area after inserting the new filled graphic is greater than or equal to the minimum requirement DYS of the graphic density of the local area. If the largest filling pattern allowed by this kind of production process is used, and the pattern density DYi after virtual insertion is still less than the minimum requirement DYS of the pattern density of the local area, an error is reported. After receiving the reported error, the layout designer will consider modifying the layout data to meet the minimum requirements for graphic density.
[0033] See figure 2 , The method of inserting filling graphics in the above layout can be improved as follows. Furthermore, for each production process, a table of the size and density of the filling pattern is formulated, as shown in the following table.
[0034]
[0035] Among them, A1 and B1 respectively represent the length of two sides of the standard filling pattern A (rectangle) of this kind of production process. x and y respectively represent the unit size added on the two sides of the standard filling figure A. Both m and n are natural numbers. A1+mx and B1+ny respectively represent the two side lengths of the maximum filling pattern allowed by the production process. DEN11, ..., DENmn represent the density of the graphics corresponding to the filled graphics with different side lengths. Each production process has a minimum requirement for the spacing between filling patterns. Under the minimum required spacing condition, the larger the area of the filling pattern, the higher the corresponding pattern density.
[0036] Correspondingly, in the third step of the method, if the graphic density DYi of the local area after inserting the filled graphic is less than the minimum requirement DYS of the graphic density of the local area, it is calculated that the local area is removing the filled graphic, and In the case of inserting a new filled figure instead, in order to meet the minimum requirement of the figure density of the local area, the figure density of the new filled figure DYn=(DYS-(1-Ai)DYr)/Ai. Wherein, DYr is the pattern density value of the structure in the local area that is forbidden to insert filled patterns, and Ai is the ratio of the area occupied by the structure that allows the insertion of filled patterns in the local area to the total area of the local area. Since DYr=X/[Z(1-Ai)], so DYn=(DYS-X/Z)/Ai.
[0037] Correspondingly, in the fourth step of the method, according to the minimum pattern density DYn required to switch to a new filling pattern calculated in step 3, compare the size and pattern density tables of different filling patterns under this production process, from In the table, find the filled figure with the smallest size with a figure density greater than DYn, and repeat steps 3 to 4. If DYn is greater than the density of all graphics in the table, an error is reported. If after using the largest-size filled graphics in the table, the calculated graphics density DYi of the partial area after inserting the largest-size filled graphics is still less than the minimum requirement DYS of the partial area's graphics density, an error is reported.
[0038] The following will take a specific example to figure 2 The improved method of inserting and filling graphics in the layout is described in detail. The production process of a certain semiconductor integrated circuit divides a chip layout 10 with a size of 2100μm*2100μm into 9 partial regions 20, each of which is 700μm*700μm in size, such as image 3 Shown. The production process requires that the pattern density of each local area 20 must be above 30%, that is, DYS=30%. The standard filling pattern A used in the production process is a rectangle with a size of 2 μm * 4 μm, and the maximum filling pattern allowed to be used is a rectangle with a size of 10 μm * 10 μm. The step length of each side of the filled pattern is 1 μm. The spacing between each filling pattern is fixed at 2 μm.
[0039] According to the above-mentioned information stipulated by the production process, the following relationship table between the size of the filling pattern and the pattern density is established.
[0040]
[0041] According to the method of inserting filled graphics in the layout of this application, the layout data is first read to find the structure that allows the insertion of filled graphics in each local area 20. See Figure 4 , The blank part is the structure that allows the insertion of filling graphics, and the shadow filling part is the structure that prohibits the insertion of filling graphics. Then, in the structure of each partial area 20 that allows the insertion of the filling figure, the standard filling figure A is virtually inserted. Assuming that except for the partial areas 21 and 22, the remaining partial areas can meet the minimum pattern density requirement of 30% after inserting the standard filling pattern A. These partial areas are inserted into the 2μm*4μm standard filling pattern A as Figure 5a Shown.
[0042] For the first partial area 21, 30% of which is forbidden to insert filled graphics, that is, Ai=70%. In the part where the filling of graphics is prohibited, the density of the graphics is 15%, that is, DYr=15%. Then, in order to meet the minimum pattern density requirement of 30% of the first partial area 21, the minimum pattern density of the filling pattern of the first partial area 21 is DYn=(DYS-(1-Ai)DYr)/Ai=36.43%. Looking up the table, we can see that selecting a 3*4 filled pattern can reach a pattern density of 40%, which is also a pattern density> 36.43% of the smallest size filled graphics. Therefore, a 3*4 filled figure is selected and calculated after virtual insertion, so that the first partial area 21 meets the minimum figure density requirement of 30%. Then the first partial area 21 uses a 3*4 filling pattern for array insertion in a structure that allows the insertion of filling patterns, such as Figure 5b Shown.
[0043] For the second partial area 22, 60% of which is forbidden to insert filled graphics, that is, Ai=40%. In the part where the insertion of filled graphics is prohibited, the density of the graphics is 8%, that is, DYr=8%. Then, in order to meet the minimum pattern density requirement of 30% of the second partial area 22, the minimum pattern density of the filling pattern of the second partial area 22 is DYn=(DYS-(1-Ai)DYr)/Ai=63.00%. Looking up the table, we can see that selecting 9*9 filled graphics can reach 66% graphics density, which is also graphics density> 63.00% minimum size filled graphics. However, after the virtual insertion, it is found that due to the shape limitation of the structure that allows the insertion of the filling graphics in the second partial area 22, the graphic density still does not meet the minimum graphic density requirement of 30%. Look up the table again, select 9*10 or 10*9 filled graphics, and calculate after virtual insertion, so that the second local area 22 meets the minimum graphics density requirement of 30%. Then the second partial area 22 uses 9*10 or 10*9 filled graphics to be inserted in an array in a structure that allows the insertion of filled graphics, such as Figure 5c Shown.
[0044] In the method of inserting filled graphics in the layout of this application, filling graphics of different sizes can be inserted in different local areas, so that each local area meets the minimum graphic density requirement.
[0045] The above are only preferred embodiments of the application, and are not used to limit the application. For those skilled in the art, this application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc., made within the spirit and principle of this application shall be included in the protection scope of this application.
