FLARE VALUE CALCULATION METHOD, FLARE CORRECTION METHOD, AND COMPUTER PROGRAM PRODUCT

• US 20120198395A1
• Filed: 09/21/2011
• Published: 08/02/2012
• Est. Priority Date: 01/28/2011
• Status: Active Grant

• Current Assignee: Kioxia Corporation
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Arisawa, Yukiyasu, Uno, Taiga
• Granted Patent: US 8,443,311 B2
• Time in Patent Office: Days
• US Class Current: 716/53
• CPC Class Codes: G03F 1/36 Masks having proximity correction features; Preparation thereof, e.g. optical proximity correction [OPC] design processes
• CPC Class Codes: G03F 1/70 Adapting basic layout or design of masks to lithographic process requirements, e.g., second iteration correction of mask patterns for imaging
• CPC Class Codes: G03F 7/70941 Stray fields and charges, e.g. stray light, scattered light, flare, transmission loss

Abstract

In a flare value calculation method according to an embodiment, an average optical intensity is calculated for each of mask patterns in a case where an exposure process is performed on a substrate using the mask patterns. Then, pattern correction amounts for the mask patterns corresponding to the average optical intensity and information about the dimensions of the mask patterns are calculated for each mask pattern. Then, post-correction mask patterns are prepared by performing pattern correction on each of the mask patterns using the pattern correction amount. Then, a flare value of an optical system of an exposure apparatus is calculated using a pattern average density of the post-correction mask patterns.

Claims

1. A flare value calculation method comprising:

calculating an average optical intensity for each of mask patterns when an exposure process is performed on a substrate using a mask pattern group including the mask patterns of a plurality of dimensions;

calculating a pattern correction amount for each of the mask patterns corresponding to the average optical intensity and information about the dimensions of the mask patterns;

preparing post-correction mask patterns by performing pattern correction on each of the mask patterns using the pattern correction amount calculated for each of the mask patterns; and

calculating a flare value of a projection optical system of an exposure apparatus using a pattern average density of the post-correction mask patterns.

2. The method of claim 1,

wherein the preparing of the post-correction mask pattern is performed by moving a pattern edge of the mask pattern according to a function defined by dimensions of the mask pattern including the pattern edge and a distance between the pattern edge and a neighboring pattern adjacent to the pattern edge.

3. The method of claim 2,

wherein if a mask where the mask pattern is disposed is a reflective mask, the pattern edge of the mask pattern is moved according to the function so that the pattern average density becomes equal to reflectance of the reflective mask, and

if a mask where the mask pattern is disposed is a transmissive mask, the pattern edge of the mask pattern is moved according to the function so that the pattern average density becomes equal to transmittance of the transmissive mask.

4. The method of claim 1,

wherein the information about the dimensions of the mask patterns is an average density of the mask patterns.

5. The method of claim 1,

wherein the pattern correction amount is calculated using information about dimensions of another mask pattern, an average optical intensity calculated from the another mask pattern, and a pattern correction amount calculated from the another mask pattern.

6. The method of claim 1,

wherein the plurality of dimensions are dimensions determined by combining line pattern dimensions and space pattern dimensions.

7. A flare correction method comprising:

calculating an average optical intensity for each of mask patterns when an exposure process is performed on a substrate using a mask pattern group including the mask patterns of a plurality of dimensions;

calculating a pattern correction amount for each of the mask patterns corresponding to the average optical intensity and information about the dimensions of the mask patterns;

preparing post-correction mask patterns by performing pattern correction on each of the mask patterns using the pattern correction amount calculated for each of the mask patterns;

calculating a flare value of a projection optical system of an exposure apparatus using a pattern average density of the post-correction mask pattern; and

performing flare correction on correction-target mask patterns by changing dimensions of the correction-target mask patterns according to the flare value.

8. The method of claim 7,

wherein the performing of the flare correction comprises:

dividing the correction-target mask patterns into a plurality of cell areas in a mask surface;

calculating a flare value to be received by a cell serving as a flare value calculation target cell from another cell, the calculating being performed for each cell using a pattern average density calculated for each cell and a function defining flare influence;

performing flare correction on mask patterns disposed on the mask surface in a way of performing flare correction on a mask pattern disposed in the flare value calculation target cell, based on an integrated amount of a flare value given to the flare value calculation target cell by the another cell.

9. The method of claim 7,

wherein the preparing of the post-correction mask pattern is performed by moving a pattern edge of the mask pattern according to a function defined by dimensions of the mask pattern including the pattern edge and a distance between the pattern edge and a neighboring pattern adjacent to the pattern edge.

10. The method of claim 9,

wherein if a mask where the mask pattern is disposed is a reflective mask, the pattern edge of the mask pattern is moved according to the function so that the pattern average density becomes equal to reflectance of the reflective mask, and

if a mask where the mask pattern is disposed is a transmissive mask, the pattern edge of the mask pattern is moved according to the function so that the pattern average density becomes equal to transmittance of the transmissive mask.

11. The method of claim 7,

wherein the information about the dimensions of the mask patterns is an average density of the mask patterns.

12. The method of claim 7,

wherein the pattern correction amount is calculated using information about dimensions of another mask pattern, an average optical intensity calculated from the another mask pattern, and a pattern correction amount calculated from the another mask pattern.

13. The method of claim 7,

wherein the plurality of dimensions are dimensions determined by combining line pattern dimensions and space pattern dimensions.

14. A computer program product comprising a computer-readable recording medium storing a plurality of commands which are executable on a computer and configured to calculate a flare value of an optical system of an exposure apparatus, the plurality of commands causing the computer to execute:

calculating an average optical intensity for each of mask patterns when an exposure process is performed on a substrate using a mask pattern group including the mask patterns of a plurality of dimensions;

calculating a pattern correction amount for each of the mask patterns corresponding to the average optical intensity and information about the dimensions of the mask patterns;

preparing post-correction mask patterns by performing pattern correction on each of the mask patterns using the pattern correction amount calculated for each of the mask patterns; and

calculating a flare value of a projection optical system of an exposure apparatus using a pattern average density of the post-correction mask patterns.

15. The computer program product according to claim 14,

wherein the preparing of the post-correction mask pattern is performed by moving a pattern edge of the mask pattern according to a function defined by dimensions of the mask pattern including the pattern edge and a distance between the pattern edge and a neighboring pattern adjacent to the pattern edge.

16. The computer program product according to claim 15,

wherein if a mask where the mask pattern is disposed is a reflective mask, the pattern edge of the mask pattern is moved according to the function so that the pattern average density becomes equal to reflectance of the reflective mask, and

if a mask where the mask pattern is disposed is a transmissive mask, the pattern edge of the mask pattern is moved according to the function so that the pattern average density becomes equal to transmittance of the transmissive mask.

17. The computer, program product according to claim 14,

wherein the information about the dimensions of the mask patterns is an average density of the mask patterns.

18. The computer program product according to claim 14,

wherein the pattern correction amount is calculated using information about dimensions of another mask pattern, an average optical intensity calculated from the another mask pattern, and a pattern correction amount calculated from the another mask pattern.

19. The computer program product according to claim 14,

wherein the plurality of dimensions are dimensions determined by combining line pattern dimensions and space pattern dimensions.