Pattern sorting method used in OPC verification

Patent metadata

Field	Value
Publication number	US-10409153-B2
Application number	US-201715850878-A
Country	US
Kind code	B2
Filing date	Dec 21, 2017
Priority date	Apr 27, 2017
Publication date	Sep 10, 2019
Grant date	Sep 10, 2019

Abstract

A pattern sorting method used in OPC verification, comprises the following steps: obtaining sizes of comparison areas of patterns and extracting pattern boundaries; processing pattern boundaries; cutting off all the pattern edges outside comparison areas; setting grid sizes for filtering; setting directions for pattern boundaries; pattern division processing: dividing each pattern into 4 blocks of an equal size; recalculating the apexes of pattern boundaries in each block; implementing coordinate transformation for each block; calculating block characteristic values for each block; implementing rotating, upward and downward mirroring or leftward and rightward mirroring adjustment for blocks in accordance with corresponding block characteristic values; calculating overall characteristic values of patterns in accordance with various block characteristic values. This method is capable of sorting patterns related to each other by rotations or mirroring as well as patterns having subtle differences between one another into the same categories of patterns, thereby reducing the number of verification results as well as difficulties in screening problems.

First claim

What is claimed is:

1. A pattern sorting method used in OPC verification, comprising the following steps:
Step I, obtaining the size of the comparison area for the patterns and extracting the pattern boundaries of said patterns within the comparison area;
Step II, processing said pattern boundaries within said comparison areas for said patterns, which includes the following substeps:
Substep 21 , cutting off the edges of said patterns outside said comparison areas;
Substep 22 , setting of grid sizes for filtering so that the apexes of the boundaries of the said patterns all move to the closest grid points with the grid sizes that are multiples of said grid sizes; degenerating the grid points on the same straight line so as to filter all the deviations from said grid sizes;
Substep 23 , setting the directions for the boundaries of the said patterns in accordance with same rules;

Step III, partitioning the said patterns having completed the boundary processing for the said patterns, which includes the following substeps:
Substep 31 , dividing the said pattern into four blocks of an equal size;
Substep 32 , recalculating the apex of the boundary for each said pattern in each block in accordance with the result of partitioning;
Substep 33 , for each block, implementing the coordinate transformation by taking the center of partitioning in Substep 31 as the origin and shift the corresponding block into the first quadrant;

Step IV, calculating the block characteristic value of each block that has completed coordinate transformation; the said block characteristic value for each said block is calculated in accordance with the apex coordinates of each said pattern boundary as well as by adopting the method of being divided by prime and taking remainders, with the said block characteristic value for each said block comprising two componential values;
Step V, block adjustment, which includes: in accordance with the characteristic values of the said blocks and based on the array structure of the blocks divided by Substep 31 , implementing the rotation, upward and downward mirroring or leftward and rightward mirroring, so as to sorting patterns related to each other by rotations or mirroring, into the same categories of patterns; and
Step VI, based on the calculation of the said block characteristic values, obtaining the overall characteristic values of the said patterns having completed block adjustments.

2. The pattern sorting method used in OPC verification of claim 1 , wherein the size of the comparison area for said patterns as obtained in said Step I is obtained by taking the wrong point of OPC verification as the center.

3. The pattern sorting method used in OPC verification of claim 2 , wherein the comparison area for said patterns as obtained in said Step I is a square or a rectangle obtained by taking the wrong point of OPC verification as the center.

4. The pattern sorting method used in OPC verification of claim 3 , wherein the size of the comparison area for said patterns as obtained in said Step I is set according to different OPC models.

5. The pattern sorting method used in OPC verification of claim 4 , wherein the size of the comparison area for said patterns as obtained in said Step I is the minimal rectangle containing the said wrong point of OPC verification, plus a further outward extension of 1˜2 μm.

6. The pattern sorting method used in OPC verification of claim 5 , wherein the grid size as mentioned in Substep 22 is set to be tens of nanometers.

7. The pattern sorting method used in OPC verification of claim 1 , wherein in Substep 23 , the direction of the boundary of the said pattern is set in anti-clockwise direction; or in Substep 23 , the direction of the boundary of the said pattern is set in clockwise direction.

8. The pattern sorting method used in OPC verification of claim 1 , wherein the calculation of the characteristic values of said blocks in said Step IV includes the following substeps:
Substep 41 , selecting a first prime and a second prime for division and remainder taking;
Substep 42 , based on the starting point coordinates and the ending point coordinates of the said pattern boundaries as well as the said first prime and the said second prime, calculating the characteristic values of the lines for the said pattern boundaries in said blocks;
Substep 43 , determining the number of said pattern boundaries for corresponding said blocks, and if there is only one line of said pattern boundaries, then the characteristic values of the line for this pattern boundary will be taken as the said block characteristic values for the entire said block; if there are over two lines of said pattern boundaries, then proceed by following Substep 44 ;
Substep 44 , arranging the said pattern boundaries into sequences of lines in accordance with the rule as defined in Substep 23 ; by following the direction of the sequence of said lines, and in combination with the said first prime and the said second prime, successively incorporating the line characteristic values of said pattern boundaries of two adjacent lines into a single line characteristic value, and finally obtaining an overall line characteristic value and taking this overall line characteristic value as the said block characteristic value of the entire said block.

9. The pattern sorting method used in OPC verification of claim 8 , wherein the calculation of the said line characteristic values for the said pattern boundaries as mentioned in said Substep 42 is made by the following formulae:
E 1=[( X 1+ X 2+ a 11×( Y 1+ Y 2)+ a 12+ X 1)×( Y 1+ Y 2+ a 13×( X 1+ X 2)+ a 14+ Y 1)]% P;

E 2=[( Y 1+ Y 2+ a 15×( Y 1+ Y 2)+ a 16+ X 2)×( Y 1+ Y 2+ a 17×( X 1+ X 2)+ a 18+ Y 2)]% Q;

wherein E 1 represents a first componential value of the said line characteristic value; E 2 represents a second componential value of the said line characteristic value; P represents the first prime; Q represents the second prime; X 1 represents a horizontal ordinate of the starting point for the corresponding line; Y 1 represents a vertical ordinate of the starting point for the corresponding line; X 2 represents a horizontal ordinate of the ending point for the corresponding line; Y 2 represents a vertical ordinate of the ending point for the corresponding line; a 11 , a 12 , a 13 , a 14 , a 15 , a 16 , a 17 and a 18 are all primes, different from one another, smaller than either of the first prime and the second prime.

10. The pattern sorting method used in OPC verification of claim 9 , wherein the specific steps of incorporating the line characteristic values of said pattern boundaries of two adjacent lines into a single line characteristic value in accordance with said Substep 44 include:
taking the values of E 1 and E 2 of a previous pattern boundary as X 1 and Y 1 , respectively;
taking the values of E 1 and E 2 of a subsequent pattern boundary as X 2 and Y 2 , respectively; substitute the converted values of X 1 , Y 1 , X 2 and Y 2 into the following formulae:
E 1=[( X 1+ X 2+ a 21×( Y 1+ Y 2)+ a 22+ X 1)×( Y 1+ Y 2+ a 23×( X 1+ X 2)+ a 24+ Y 1)]% P;

E 2=[( Y 1+ Y 2+ a 25×( Y 1+ Y 2)+ a 26+ X 2)×( Y 1+ Y 2+ a 27×( X 1+ X 2)+ a 28+ Y 2)]% Q;

wherein E 1 represents the first componential value of the said line characteristic value after incorporation; E 2 represents the second componential value of the said line characteristic value after incorporation; a 21 , a 22 , a 23 , a 24 , a 25 , a 26 , a 27 and a 28 are all primes, different from one another, smaller than either of the first prime and the second prime; the values of a 21 , a 22 , a 23 , a 24 , a 25 , a 26 , a 27 and a 28 are all

Assignees

• Shanghai Huahong Grace Semiconductor Mfg Corp

Inventors

• Jin Xiaoliang
• Yuan Chunyu

Classifications

• G06F30/398

  Design verification or optimisation, e.g. using design rule check [DRC], layout versus schematics [LVS] or finite element methods [FEM] (optical proximity correction [OPC] design processes G03F1/36) · CPC title

• G06F2111/20

  Configuration CAD, e.g. designing by assembling or positioning modules selected from libraries of predesigned modules · CPC title

• G06F30/3323

  using formal methods, e.g. equivalence checking or property checking · CPC title

• G06T7/0004 Primary

  Industrial image inspection · CPC title

• G03F1/36 Primary

  Masks having proximity correction features; Preparation thereof, e.g. optical proximity correction [OPC] design processes · CPC title