System and method for lithography simulation

• US 7,873,937 B2
• Filed: 09/26/2006
• Issued: 01/18/2011
• Est. Priority Date: 10/07/2003
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: Chen, Luoqi, Chen, Xun, Lu, Yen-Wen, Ye, Jun, Cao, Yu
• Primary Examiner(s): Kik; Phallaka
• Application Number:
  US11/527,010
• Publication Number:
  US 20070022402A1
• Time in Patent Office: 1,575 Days
• Field of Search: 716/21, 430/5, 378/35, 382/144, 700/120, 700/121
• US Class Current: 716/55
• CPC Class Codes: G03F 1/00 Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
• CPC Class Codes: G03F 7/004 Photosensitive materials G03F7/12, G03F7/14 take precedence
• CPC Class Codes: G03F 7/705 Modelling or simulating from physical phenomena up to complete wafer processes or whole workflow in wafer productions
• CPC Class Codes: G03F 7/70666 Aerial image, i.e. measuring the image of the patterned exposure light at the image plane of the projection system
• CPC Class Codes: G06F 2119/18 Manufacturability analysis or optimisation for manufacturability
• CPC Class Codes: G06F 30/20 Design optimisation, verification or simulation optimisation, verification or simulation of circuit designs G06F30/30
• CPC Class Codes: G06F 30/333 Design for testability [DFT], e.g. scan chain or built-in self-test [BIST]
• CPC Class Codes: G06F 30/398 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 Class Codes: G06T 2207/30148 Semiconductor; IC; Wafer
• CPC Class Codes: G06T 7/0004 Industrial image inspection
• CPC Class Codes: G16Z 99/00 Subject matter not provided for in other main groups of this subclass
• CPC Class Codes: G21K 5/00 Irradiation devices discharge tubes for irradiating H01J37/00

Abstract

A system has been developed for simulating, verifying, inspecting, characterizing, determining and/or evaluating the lithographic designs, techniques and/or systems, and/or individual functions performed thereby or components used therein. In one embodiment, the system accelerates lithography simulation, inspection, characterization and/or evaluation of the optical characteristics and/or properties, as well as the effects and/or interactions of lithographic systems and processing techniques. In this regard, in one embodiment, the system employs a lithography simulation system architecture, including application-specific hardware accelerators, and a processing technique to accelerate and facilitate verification, characterization and/or inspection of a mask design, for example, RET design, including detailed simulation and characterization of the entire lithography process to verify that the design achieves and/or provides the desired results on final wafer pattern. The system includes: (1) general purpose-type computing device(s) to perform the case-based logic having branches and inter-dependency in the data handling and (2) accelerator subsystems to perform a majority of the computation intensive tasks.

Claims

1. A system to simulate a lithographic design comprised of a plurality of polygons arranged in a predetermined configuration, the system comprising:

a microprocessor subsystem to convert a circuit design database, which is representative of a integrated circuit pattern, to a pixel-based bitmap representation thereof, wherein the pixel-based bitmap includes pixel data; and

an accelerator subsystem, coupled to the microprocessor subsystem, to calculate at least a portion of an aerial image of the lithographic design using the pixel-based bitmap representation of the lithographic design.

2. The system of claim 1, further including a plurality of accelerator subsystems, wherein each accelerator subsystem is coupled to the microprocessor subsystem and provided a portion of the pixel-based bitmap to calculate an aerial image of the lithographic design corresponding to the portion of the pixel-based bitmap using the pixel data associated therewith.

3. The system of claim 1, wherein, the circuit design database includes a plurality of polygons arranged in a predetermined pattern.

4. The system of claim 1, wherein, the accelerator subsystem further includes a plurality of programmable gate arrays configured to process the pixel data in parallel.

5. The system of claim 1, wherein the lithographic design includes resolution enhancement technology and wherein the microprocessor subsystem converts a plurality of polygons, including resolution enhancement technology, to a pixel-based bitmap representation thereof.

6. The system of claim 1, wherein the microprocessor subsystem includes a plurality of microprocessors and wherein each microprocessor is coupled to at least one associated accelerator subsystem.

7. The system of claim 1, wherein the accelerator subsystem calculates an aerial image in resist formed on a wafer by the lithographic design, and wherein the accelerator subsystem calculates the aerial image in resist using the pixel-based bitmap representation of the lithographic design and a coefficient matrix representing projection and illumination optics of a photolithographic tool.

8. The system of claim 7, wherein the accelerator subsystem calculates a pattern formed on the wafer by the lithographic design.

9. The system of claim 8, further including a processing system, coupled to the microprocessor subsystem and the accelerator subsystem, to compare the calculated pattern on the wafer to a desired, predetermined pattern.

10. The system of claim 8, further including a processing system, coupled to the microprocessor subsystem and the accelerator subsystem, to determine a critical dimension (CD) of the lithographic design using the calculated pattern on the wafer.

11. The system of claim 8, further including a processing system, coupled to the microprocessor subsystem and the accelerator subsystem, to determine an edge placement of the lithographic design using the calculated pattern on the wafer.

12. The system of claim 8, further including a processing system, coupled to the microprocessor subsystem and the accelerator subsystem, to determine a printing sensitivity using patterns on the wafer calculated in response to varying coefficients of the matrix representing projection and illumination optics of a photolithographic tool.

13. The system of claim 12, wherein the coefficients of the matrix representing projection and illumination optics of a photolithographic tool are representative of one or more of a focus, dose, numerical aperture, illumination aperture, and aberration.

14. The system of claim 13, wherein the processing system determines a set of parameters of the projection and illumination optics of a photolithographic tool using the printing sensitivity.

15. The system of claim 8, further including a processing system, coupled to the microprocessor subsystem and the accelerator subsystem, to detect an error in the lithographic design in response to a comparison between the calculated pattern on the wafer and a desired, predetermined pattern.

16. The system of claim 15, wherein, in response to detecting the error, the processing system determines a modification to the lithographic design to correct the error in the lithographic design.

17. A system for simulating a lithographic processing of an integrated circuit design, the system comprising:

a microprocessor subsystem to perform a first portion of the simulating; and

a co-processing accelerator, coupled to the microprocessor subsystem, to perform a second portion of the simulating, the second portion including calculating at least a portion of an aerial image of the integrated circuit design, wherein the co-processing accelerator includes a plurality of processors configured to perform the second portion in parallel.

18. The system of claim 17, wherein the second portion is more computationally intensive than the first portion.

19. The system of claim 17, wherein the first portion includes processing at least a portion of the integrated circuit design into a pixel-based bitmap.

20. The system of claim 19, wherein the pixel-based bitmap comprises a gray-level image which is representative of a plurality of polygons in the integrated circuit design.

21. The system of claim 19, wherein the co-processing accelerator performs Fast Fourier Transforms, using pixel data, to generate the corresponding portion of the aerial image.

22. The system of claim 19, wherein the co-processing accelerator further calculates a resist image corresponding to the portion of the aerial image formed on a wafer by the integrated circuit design using the pixel-based bitmap representation of the integrated circuit design and a coefficient matrix representing projection and illumination optics of a lithographic tool.

23. The system of claim 22, further including a processing system, coupled to the microprocessor subsystem and the accelerator subsystem, to compare the calculated pattern on the wafer to a desired, predetermined pattern.

24. The system of claim 22, further including a processing system, coupled to the microprocessor subsystem and the accelerator subsystem, to determine a critical dimension (CD) of the lithographic design using the calculated pattern on the wafer.

25. The system of claim 22, further including a processing system, coupled to the microprocessor subsystem and the accelerator subsystem, to determine an edge placement of the lithographic design using the calculated pattern on the wafer.

26. The system of claim 22, further including a processing system, coupled to the microprocessor subsystem and the accelerator subsystem, to determine a printing sensitivity using patterns on the wafer calculated in response to varying coefficients of the matrix representing projection and illumination optics of a lithographic tool.

27. The system of claim 26, wherein the coefficients of the matrix representing projection and illumination optics of a lithographic tool are representative of one or more of a focus, dose, numerical aperture, illumination aperture, and aberration.

28. The system of claim 27, wherein the processing system determines a set of parameters of the projection and illumination optics of the lithographic tool using the printing sensitivity.

29. The system of claim 22, further including a processing system, coupled to the microprocessor subsystem and the accelerator subsystem, to detect an error in the lithographic design in response to a comparison between the calculated pattern on the wafer and a desired, predetermined pattern.

30. The system of claim 29, wherein, in response to detecting the error, the processing system determines a modification to the lithographic design to correct the error in the lithographic design.

31. The system of claim 17, wherein the integrated circuit design includes resolution enhancement technology and wherein the microprocessor subsystem converts a plurality of polygons in at least a portion of the design, including resolution enhancement technology, to a pixel-based bitmap representation thereof.

32. The system of claim 17, wherein the co-processing accelerator further calculates a resist image corresponding to the portion of the aerial image formed on a wafer by the integrated circuit design.

33. The system of claim 17, wherein calculating the aerial image includes modeling the aerial image path through projection optics of an imaging system used for the lithographic processing based on a given illumination scheme.

34. The system of claim 17, wherein calculating the aerial image includes decomposing an imaging system used for the lithographic processing into a plurality of coherent imaging systems.

35. The system of claim 34, wherein the coherent imaging systems comprise transmission cross coefficients (TCCs).