Source optimization for image fidelity and throughput

• US 7,623,220 B2
• Filed: 06/28/2007
• Issued: 11/24/2009
• Est. Priority Date: 02/03/2004
• Status: Active Grant

• Current Assignee: Siemens Industry Software Inc. (Siemens AG)
• Original Assignee: Mentor Graphics Corporation (Siemens AG)
• Inventors: Granik, Yuri
• Primary Examiner(s): Mathews; Alan A
• Application Number:
  US11/824,558
• Publication Number:
  US 20080174756A1
• Time in Patent Office: 880 Days
• Field of Search: 355/52, 355/67, 355/69, 355/70, 355/71, 355/77, 430/311, 430/5, 700/121, 716/20, 716/21
• US Class Current: 355/67
• CPC Class Codes: G03F 7/70108 Off-axis setting using a light-guiding element, e.g. diffractive optical elements [DOEs] or light guides
• CPC Class Codes: G03F 7/70441 Optical proximity correction [OPC]
• CPC Class Codes: G03F 7/70491 Information management, e.g. software; Active and passive control, e.g. details of controlling exposure processes or exposure tool monitoring processes
• CPC Class Codes: G03F 7/705 Modelling or simulating from physical phenomena up to complete wafer processes or whole workflow in wafer productions

Abstract

A system and method for optimizing an illumination source to print a desired pattern of features dividing a light source into pixels and determining an optimum intensity for each pixel such that when the pixels are simultaneously illuminated, the error in a printed pattern of features is minimized. In one embodiment, pixel solutions are constrained from solutions that are bright, continuous, and smooth. In another embodiment, the light source optimization and resolution enhancement technique(s) are iteratively performed to minimize errors in a printed pattern of features.

Claims

1. A computer-readable medium storing a sequence of instructions that when executed by a computer causes the computer to perform a method, the method comprising:

receiving a layout pattern defining a desired pattern of features to be created on a wafer by a photolithographic process;

generating a desired light source distribution for the desired pattern of features, the desired light source distribution representing a light source distribution that reduces printing errors caused by the photolithographic process when printing the desired pattern of features; and

generating a modified layout pattern using the desired light source distribution, the modified layout pattern defining a corrected version of the desired pattern of features that further reduces printing errors caused by the photolithographic process when used to define a mask layout used during the printing of the desired pattern of features.

2. The computer-readable medium of claim 1, wherein the desired light source distribution is a first light source distribution, and wherein the method further comprises generating a second desired light source distribution using the modified layout pattern.

3. The computer-readable medium of claim 2, wherein the modified layout pattern is a first modified layout pattern, and wherein the method further comprises generating a second modified layout pattern using the second desired light source distribution.

4. The computer-readable medium of claim 1, wherein the method further comprises iteratively repeating the acts of generating the desired light source distribution and generating the modified layout pattern until a desired tolerance is reached.

5. The computer-readable medium of claim 1, wherein the desired light source distribution comprises data for implementing a diffractive optical element.

6. The computer-readable medium of claim 1, wherein the method further comprises storing at least one of the desired light source distribution or the modified layout pattern in a computer-readable medium.

7. The computer-readable medium of claim 1, wherein the act of generating the modified layout pattern comprises performing a resolution enhancement technique for the layout pattern using the desired light source distribution.

8. The computer-readable medium of claim 1, wherein the layout pattern is a portion of a larger layout pattern.

9. A computer-readable medium storing a sequence of instructions that when executed by a computer causes the computer to perform a method, the method comprising:

receiving a layout pattern, the layout pattern defining a desired pattern of features to be created on a wafer by a photolithographic process;

generating a modified layout pattern from the layout pattern, the modified layout pattern defining a corrected version of the desired pattern of features that reduces printing errors when used to define a mask layout used during the printing of the desired pattern of features; and

generating a desired light source distribution for the corrected version of the desired pattern of features, the desired light source distribution representing a light source distribution that further reduces printing errors caused by the photolithographic process when printing the desired pattern of features.

10. The computer-readable medium of claim 9, wherein an idealized light source distribution is used when generating the modified layout pattern.

11. The computer-readable medium of claim 9, wherein the modified layout pattern is a first modified layout pattern, and wherein the method further comprises generating a second modified layout pattern using the desired light source distribution.

12. The computer-readable medium of claim 11, wherein the desired light source distribution is a first light source distribution, and wherein the method further comprises generating a second desired light source distribution using the second modified layout pattern.

13. The computer-readable medium of claim 9, wherein the method further comprises iteratively repeating the acts of generating the modified layout pattern and generating the light source distribution until a desired tolerance is reached.

14. The computer-readable medium of claim 9, wherein the desired light source distribution comprises data for implementing a diffractive optical element.

15. The computer-readable medium of claim 9, wherein the method further comprises storing at least one of the modified layout pattern or the desired light source distribution on a computer-readable medium.

16. A computer-readable medium storing a sequence of instructions that when executed by a computer causes the computer to perform a method, the method comprising:

receiving all or a portion of layout data, the layout data defining a desired pattern of features to be created on a wafer using a photolithographic process; and

generating a representation of a diffractive optical element for use in producing the desired pattern of features, the representation of the diffractive optical element being generated by representing a light source used during the photolithographic process as a number of light source pixels and determining intensity values for the light source pixels using a representation of the desired pattern of features.

17. The computer readable medium of claim 16, wherein the method further comprises storing the representation of the diffractive optical element in a computer-readable medium.

18. The computer readable medium of claim 16, wherein the determining the intensity values comprises solving a matrix equation relating the light source pixels to the representation of the desired pattern of features.

19. The computer readable medium of claim 18, wherein the representation of the desired pattern of features is a pixel-based representation comprising image pixels, each image pixel representing an area on the wafer.

20. The computer readable medium of claim 19, wherein each image pixel corresponds to a sum of contributions from a plurality of the light source pixels.

21. The computer-readable medium of claim 19, wherein the represented diffractive optical element is designed to reduce printing errors when used during the photolithographic process.

22. The computer readable medium of claim 16, wherein the layout data is layout data corrected by a resolution enhancement technique.

23. The computer readable medium of claim 16, wherein the method further comprises performing a resolution enhancement technique on the layout data, thereby generating corrected layout data defining a modified version of the desired pattern of features.

24. The computer readable medium of claim 23, wherein the resolution enhancement technique is performed using the representation of the diffractive optical element.

25. The computer-readable medium of claim 23, wherein the representation of the diffractive optical element is a first representation of the diffractive optical element, and wherein the method further comprises generating a second representation of the diffractive optical element using the corrected layout data.

26. A computer-implemented method, comprising:

receiving a layout pattern defining a desired pattern of features to be created on a wafer by a photolithographic process;

generating a desired light source distribution for the desired pattern of features, the desired light source distribution representing a light source distribution that reduces printing errors caused by the photolithographic process when printing the desired pattern of features; and

generating a modified layout pattern using the desired light source distribution, the modified layout pattern defining a corrected version of the desired pattern of features that further reduces printing errors caused by the photolithographic process when used to define a mask layout used during the printing of the desired pattern of features; and

storing the modified layout pattern in a computer-readable medium.

27. The computer-implemented method of claim 26, wherein the desired light source distribution is a first light source distribution, and wherein the method further comprises generating a second desired light source distribution using the modified layout pattern.

28. The computer-implemented method of claim 27, wherein the modified layout pattern is a first modified layout pattern, and wherein the method further comprises generating a second modified layout pattern using the second desired light source distribution.

29. The computer-implemented method of claim 26, wherein the method further comprises iteratively repeating the acts of generating the desired light source distribution and generating the modified layout pattern until a desired tolerance is reached.

30. A computer-implemented method, comprising:

receiving a layout pattern, the layout pattern defining a desired pattern of features to be created on a wafer by a photolithographic process;

generating a modified layout pattern from the layout pattern, the modified layout pattern defining a corrected version of the desired pattern of features that reduces printing errors when used to define a mask layout used during the printing of the desired pattern of features;

generating a desired light source distribution for the corrected version of the desired pattern of features, the desired light source distribution representing a light source distribution that further reduces printing errors caused by the photolithographic process when printing the desired pattern of features; and

storing the desired light source distribution in a computer-readable medium.

31. The computer-implemented method of claim 30, wherein the modified layout pattern is a first modified layout pattern, and wherein the method further comprises generating a second modified layout pattern using the desired light source distribution.

32. The computer-implemented method of claim 31, wherein the desired light source distribution is a first light source distribution, and wherein the method further comprises generating a second desired light source distribution using the second modified layout pattern.

33. The computer-implemented method of claim 30, wherein the method further comprises iteratively repeating the acts of generating the modified layout pattern and generating the light source distribution until a desired tolerance is reached.

34. A computer-implemented method, comprising:

receiving all or a portion of layout data, the layout data defining a desired pattern of features to be created on a wafer using a photolithographic process;

generating a representation of a diffractive optical element for use in producing the desired pattern of features, the representation of the diffractive optical element being generated by representing a light source used during the photolithographic process as a number of light source pixels and determining intensity values for the light source pixels using a representation of the desired pattern of features; and

storing the representation of the diffractive optical element in a computer-readable medium.