Method and apparatus for performing dark field double dipole lithography (DDL)

• US 8,632,930 B2
• Filed: 06/07/2011
• Issued: 01/21/2014
• Est. Priority Date: 04/06/2006
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Masktools B.V. (ASML Holding NV)
• Inventors: Hsu, Duan-Fu Stephen, Park, Sangbong, Van Den Broeke, Douglas, Chen, Jang Fung
• Primary Examiner(s): Huff, Mark F
• Assistant Examiner(s): Ruggles, John S
• Application Number:
  US13/155,259
• Publication Number:
  US 20110236808A1
• Time in Patent Office: 959 Days
• Field of Search: 430/5, 716 54- 55
• US Class Current: 430/5
• 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 7/70125 Use of illumination settings tailored to particular mask patterns details of setting means G03F7/70091
• CPC Class Codes: G03F 7/70466 Multiple exposures, e.g. combination of fine and coarse exposures, double patterning or multiple exposures for printing a single feature stitching G03F7/70475

Abstract

A method of generating complementary masks for use in a dark field double dipole imaging process. The method includes the steps of identifying a target pattern having a plurality of features, including horizontal and vertical features; generating a horizontal mask based on the target pattern, where the horizontal mask includes low contrast vertical features. The generation of the horizontal mask includes the steps of optimizing the bias of the low contrast vertical features contained in the horizontal mask; and applying assist features to the horizontal mask. The method further includes generating a vertical mask based on the target pattern, where the vertical mask contains low contrast horizontal features. The generation of the vertical mask includes the steps of optimizing the bias of low contrast horizontal features contained in the vertical mask; and applying assist features to the vertical mask.

Claims

1. A method of generating complementary masks for use in a dark field double dipole imaging process, the method comprising the steps of:

identifying a target pattern having a plurality of features, the plurality of features comprising horizontal and vertical features;

decomposing the target pattern into a horizontal dark field mask and a vertical dark field mask, the decomposing comprising performing model-based optimization of both masks so as to optimize imaging performance criteria after double exposure of one or more of the features in the target pattern during the dark field double dipole imaging process using both masks and linear polarization.

2. The method of generating complementary masks for use in a dark field double dipole imaging process according to claim 1, wherein the imaging performance criteria comprise one or more of ILS and NILS of a portion of a simulated image corresponding to the one or more features.

3. A non-transitory computer-readable medium configured to store program instructions for execution by a processor, said program instructions enabling the processor to generate files corresponding to complementary masks for use in a dark field double dipole imaging process, the generation of said files comprising the steps of claim 1.

4. A method of generating complementary masks for use in a dark field double dipole imaging process, said method comprising the steps of:

identifying a target pattern having a plurality of features, said plurality of features comprising horizontal and vertical features;

generating a horizontal dark field mask based on said target pattern, said horizontal dark field mask including low contrast features, said generation of said horizontal dark field mask comprising the steps of;

optimizing the bias of said low contrast features contained in said horizontal dark field mask; and

applying assist features to said horizontal dark field mask;

generating a vertical dark field mask based on said target pattern, said vertical dark field mask containing low contrast features, said generation of said vertical dark field mask comprising the steps of;

optimizing the bias of low contrast features contained in said vertical dark field mask; and

applying assist features to said vertical dark field mask; and

decomposing the target pattern into the horizontal dark field mask and the vertical dark field mask, the decomposing comprising;

performing model-based optimization of both masks so as to optimize imaging performance criteria after double exposure of a feature in the target pattern during the dark field double dipole imaging process using both masks and linear polarization.

5. The method of generating complementary masks for use in a dark field double dipole imaging process according to claim 4, wherein the model-based optimization comprises one or more of a model-based bias optimization, a model-based placement optimization, and a model-based assist feature placement optimization.

6. The method of generating complementary masks for use in a dark field double dipole imaging process according to claim 4, wherein said imaging performance criteria comprise one or more of DOF, MEF, ILS, NILS, and contrast.

7. The method of generating complementary masks for use in a dark field double dipole imaging process according to claim 6, wherein the optimization process for both masks is performed simultaneously.

8. The method of generating complementary masks for use in a dark field double dipole imaging process according to claim 6, wherein the optimization process for both masks is performed in a serial manner.

9. A non-transitory computer-readable medium configured to store program instructions for execution by a processor, said program instructions enabling the processor to generate files corresponding to complementary masks for use in a dark field double dipole imaging process, the generation of said files comprising the steps of claim 4.

10. A method of generating complementary masks for use in a dark field double dipole lithographic imaging process, said method comprising the steps of:

identifying a target pattern having a plurality of features, said plurality of features comprising horizontal and vertical features;

generating a horizontal dark field mask based on said target pattern, said horizontal dark field mask including low contrast features, said generation of said horizontal dark field mask comprising the steps of;

optimizing the bias of said low contrast features contained in said horizontal dark field mask;

applying assist features to said horizontal dark field mask; and

re-performing the step of optimizing the bias of said low contrast features after the step of applying said assist features to said horizontal dark field mask; and

generating a vertical dark field mask based on said target pattern, said vertical dark field mask containing low contrast features, said generation of said vertical dark field mask comprising the steps of;

optimizing the bias of low contrast features contained in said vertical dark field mask; and

applying assist features to said vertical dark field mask,

wherein one or both of said steps of optimizing the bias of said low contrast features contained in said horizontal dark field mask and said vertical dark field mask includes maximizing one or more imaging performance criteria using linear polarization, and wherein dimensions of said assist features applied to said horizontal dark field mask and said vertical dark field masks are adjusted based on optical energy associated with the dark field double dipole lithographic imaging process.

11. The method of generating complementary masks for use in a dark field double dipole imaging process according to claim 10, wherein the step of generating a horizontal dark field mask further includes the step of performing model-based OPC on said horizontal dark field mask.

12. The method of generating complementary masks for use in a dark field double dipole imaging process according to claim 10, wherein the step of generating said vertical dark field mask further includes the step of re-performing the step of optimizing the bias of said low contrast features after the step of applying said assist features to said vertical dark field mask.

13. The method of generating complementary masks for use in a dark field double dipole imaging process according to claim 10, wherein the step of generating a vertical dark field mask further includes the step of performing model-based OPC on said vertical dark field mask.

14. A non-transitory computer-readable medium configured to store program instructions for execution by a processor, said program instructions enabling the processor to generate files corresponding to complementary masks for use in a dark field double dipole lithographic imaging process, the generation of said files comprising the steps of claim 10.