Mask synthesis using design guided offsets

Patent metadata

Field	Value
Publication number	US-11720015-B2
Application number	US-202117359176-A
Country	US
Kind code	B2
Filing date	Jun 25, 2021
Priority date	Jun 29, 2020
Publication date	Aug 8, 2023
Grant date	Aug 8, 2023

Abstract

Aspects described herein relate to mask synthesis using design guided offsets. A target shape on an image surface to be fabricated using a mask based on a design of an integrated circuit is obtained. Rays are generated emanating from respective anchor points. The anchor points are on a boundary of the target shape or a boundary of a mask shape of the mask. For each ray of the rays, a distance is defined between a first intersection of the respective ray and the boundary of the target shape and a second intersection of the respective ray and the boundary of the mask shape. An analysis is performed by one or more processors, where the analysis is configured to modify the distances based on an error between the target shape and a resulting shape simulated to be on the image surface resulting from the mask shape.

First claim

What is claimed is:

1. A method comprising:
obtaining a target shape on an image surface to be fabricated using a mask based on a design of an integrated circuit;
generating rays emanating from respective anchor points, the anchor points being on a boundary of the target shape or a boundary of a mask shape of the mask;
defining, for each ray of the rays, a distance between
a first intersection of the respective ray and the boundary of the target shape and
a second intersection of the respective ray and the boundary of the mask shape;

modifying, by one or more processors, the distance based on an error between the target shape and a resulting shape simulated to be on the image surface resulting from the mask shape; and
generating a mask design for the mask that is to be used to fabricate the target shape on the image surface based on the modified distance.

2. The method of claim 1 , further comprising generating an owned region boundary in the target shape, wherein the rays do not extend beyond the owned region boundary.

3. The method of claim 1 , further comprising generating an owned region boundary in a space disposed between the target shape and one or more other target shapes, wherein the rays do not extend across the owned region boundary.

4. The method of claim 3 , wherein the owned region boundary is generated using a medial axis transform of the target shape.

5. The method of claim 4 , wherein the owned region is user defined.

6. The method of claim 3 , wherein the mask shape comprises an edge that coincident with a portion of the owned region.

7. The method of claim 1 , wherein generating the mask design comprises modifying the mask shape such that the mask shape is formed into multiple non-overlapping mask shapes or such that the mask shape merges with another mask shape.

8. The method of claim 1 , wherein one or more of the rays emanate from a corner of the target shape or the mask shape.

9. The method of claim 8 , wherein the one or more of the rays comprise a first ray, a second ray, and a third ray emanating from the corner, and wherein an angle between the first ray and the second ray is the same as an angle between the second ray and the third ray.

10. The method of claim 1 , wherein modifying the distance between the target shape and the resulting shape is based on a rule table.

11. The method of claim 1 , further comprising determining a sensitivity, the sensitivity representing a ratio of a change in the error to a change of the distance, wherein modifying the distance is based on the sensitivity.

12. The method of claim 1 , wherein the masked shape comprises lines that are parallel with an edge of the target shape, each of the lines being through the second intersection of one of the rays and the masked shape.

13. The method of claim 12 , wherein two of the lines are connected by another line that is perpendicular to the edge of the target shape.

14. An apparatus comprising:
a memory; and
one or more processors coupled to the memory, the memory and the one or more processors being configured to:
obtain a target shape on an image surface to be fabricated using a mask based on a design of an integrated circuit;
generate rays emanating from respective anchor points, the anchor points being on a boundary of the target shape or a boundary of a mask shape of the mask;
define, for each ray of the rays, a distance between
a first intersection of the respective ray and the boundary of the target shape and
a second intersection of the respective ray and the boundary of the mask shape; and

perform an analysis configured to modify the distance based on an error between the target shape and a resulting shape simulated to be on the image surface resulting from the mask shape.

15. The apparatus of claim 14 , wherein the memory and the one or more processors are further configured to generate an owned region boundary in the target shape, wherein the rays do not extend beyond the owned region boundary.

16. The apparatus of claim 15 , wherein the owned region boundary is generated using a medial axis transform of the target shape.

17. The apparatus of claim 16 , wherein the owned region is user defined.

18. The apparatus of claim 15 , wherein the mask shape comprises an edge that coincident with a portion of the owned region.

19. The apparatus of claim 14 wherein the memory and the one or more processors are further configured to generate an owned region boundary in a space disposed between the target shape and one or more other target shapes, wherein the rays do not extend across the owned region boundary.

20. A non-transitory computer-readable medium comprising executable instructions that, when executed by one or more processors of an apparatus, cause the apparatus to:
obtain a target shape on an image surface to be fabricated using a mask based on a design of an integrated circuit;
generate rays emanating from respective anchor points, the anchor points being on a boundary of the target shape or a boundary of a mask shape of the mask;
define, for each ray of the rays, a distance between
a first intersection of the respective ray and the boundary of the target shape and
a second intersection of the respective ray and the boundary of the mask shape; and

perform an analysis, by the one or more processors, configured to modify the distance based on an error between the target shape and a resulting shape simulated to be on the image surface resulting from the mask shape.

Assignees

• Synopsys Inc

Inventors

• Cecil Thomas
• Hooker Kevin

Classifications

• G06T11/23

  using straight lines or curves · CPC title

• G03F1/70 Primary

  Adapting basic layout or design of masks to lithographic process requirements, e.g., second iteration correction of mask patterns for imaging · CPC title

• G03F1/36 Primary

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

• G06T7/536

  from perspective effects, e.g. by using vanishing points · CPC title

• G06T2207/10028

  Range image; Depth image; 3D point clouds · CPC title