Method and system for forming patterns using charged particle beam lithography with variable pattern dosage

• US 9,372,391 B2
• Filed: 07/25/2015
• Issued: 06/21/2016
• Est. Priority Date: 09/01/2008
• Status: Active Grant

• Current Assignee: D2S, Inc.
• Original Assignee: D2S, Inc.
• Inventors: Fujimura, Akira, Zable, Harold Robert
• Primary Examiner(s): Young, Christopher
• Application Number:
  US14/809,188
• Publication Number:
  US 20150331991A1
• Time in Patent Office: 332 Days
• Field of Search: 430/5, 430/30, 430/296, 430/396, 430/942, 716/53, 716/55
• US Class Current: 1/1
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: G03F 1/20 Masks or mask blanks for imaging by charged particle beam [CPB] radiation, e.g. by electron beam; Preparation thereof
• 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 1/78 by charged particle beam [CPB], e.g. electron beam patterning of masks
• CPC Class Codes: G03F 7/20 Exposure; Apparatus therefor photographic printing apparatus for making copies G03B27/00
• CPC Class Codes: G03F 7/2037 Exposure with X-ray radiation or corpuscular radiation, through a mask with a pattern opaque to that radiation
• CPC Class Codes: G03F 7/2063 for the production of exposure masks or reticles
• CPC Class Codes: G03F 7/7025 Size or form of projection system aperture, e.g. aperture stops, diaphragms or pupil obscuration; Control thereof
• CPC Class Codes: G06F 30/00 Computer-aided design [CAD]
• CPC Class Codes: G06F 30/39 Circuit design at the physical level physical level design for reconfigurable circuits G06F30/347
• 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: H01J 2237/31764 Dividing into sub-patterns
• CPC Class Codes: H01J 2237/31771 using multiple exposure
• CPC Class Codes: H01J 2237/31776 Shaped beam
• CPC Class Codes: H01J 37/3026 Patterning strategy
• CPC Class Codes: H01J 37/3174 Particle-beam lithography, e.g. electron beam lithography
• CPC Class Codes: H01J 37/3177 Multi-beam, e.g. fly's eye, comb probe
• CPC Class Codes: Y10S 430/143 Electron beam

Abstract

A method and system for fracturing or mask data preparation or optical proximity correction or proximity effect correction or mask process correction is disclosed in which a set of shaped beam shots is determined that is capable of forming a pattern on a surface, where the set of shots provides different dosages to different parts of the pattern, and where the dose margin from the set of shots is calculated. A method for forming patterns on a surface is also disclosed.

Claims

1. A method for fracturing or mask data preparation or proximity effect correction or optical proximity correction or mask process correction comprising the step of:

determining a plurality of shaped beam charged particle beam shots for an exposure pass, wherein the plurality of shaped beam shots, when used in a charged particle beam writer, produces a dosage on a resist-coated surface, wherein the dosage on the resist-coated surface forms a pattern on the resist-coated surface, wherein the pattern on the surface comprises a pattern perimeter, wherein the resist comprises a resist threshold, wherein the plurality of shaped beam shots provides different dosages to different parts of the pattern, wherein the step of determining comprises calculating a dose margin from the plurality of shaped beam shots, wherein the dose margin is a slope of the resist dosage, at the resist threshold, with respect to a linear dimension perpendicular to the pattern perimeter, and wherein the step of determining is performed using one or more computing hardware processors.

2. The method of claim 1 wherein the dose margin is optimized.

3. The method of claim 2 wherein the plurality of shaped beam shots produces a higher resist dosage peak near the pattern perimeter than in an interior area of the pattern on the surface.

4. The method of claim 1 wherein the calculating comprises charged particle beam simulation.

5. The method of claim 4 wherein the charged particle beam simulation includes at least one of a group consisting of forward scattering, backward scattering, resist diffusion, Coulomb effect, etching, fogging, loading and resist charging.

6. The method of claim 1, further comprising the step of revising the plurality of shaped beam shots and recalculating the dose margin if the dose margin is lower than a pre-determined target dose margin.

7. The method of claim 1 wherein each shot in the plurality of shaped beam shots comprises an assigned dosage, and wherein the assigned dosages of at least two shots in the plurality of shaped beam shots differ from each other before dosage correction for long-range effects.

8. The method of claim 1 wherein each shot in the plurality of shaped beam shots is a variable shaped beam (VSB) shot.

9. The method of claim 1 wherein the surface comprises a reticle to be used in an optical lithographic process to manufacture a substrate.

10. A method for manufacturing a surface using charged particle beam lithography, the method comprising the steps of:

determining a plurality of shaped beam shots for a plurality of exposure passes; and

forming a pattern on the surface, wherein the surface has been coated with a resist, wherein a charged particle beam writer produces a dosage on the resist-coated surface using the plurality of shaped beam shots, wherein the dosage on the resist-coated surface forms the pattern, wherein the pattern on the surface comprises a pattern perimeter, wherein the resist comprises a resist threshold,

wherein the plurality of shaped beam shots provides different dosages to different parts of the pattern, wherein the step of determining comprises calculating a dose margin from the plurality of shaped beam shots, and wherein the dose margin is a slope of the resist dosage, at the resist threshold, with respect to a linear dimension perpendicular to the pattern perimeter.

11. The method of claim 10 wherein the dose margin is optimized.

12. The method of claim 11 wherein the plurality of shaped beam shots produces a higher resist dosage peak near the pattern perimeter on the surface than in an interior area of the pattern on the surface.

13. The method of claim 10 wherein the calculating comprises charged particle beam simulation.

14. The method of claim 13 wherein the charged particle beam simulation includes at least one of a group consisting of forward scattering, backward scattering, resist diffusion, Coulomb effect, etching, fogging, loading and resist charging.

15. The method of claim 10, further comprising the step of revising the plurality of shaped beam shots and recalculating the dose margin if the dose margin is lower than a pre-determined target dose margin.

16. The method of claim 10 wherein each shot in the plurality of shaped beam shots comprises an assigned dosage, and wherein the assigned dosages of at least two shots in the plurality of shaped beam shots differ before dosage correction for long-range effects.

17. The method of claim 16, further comprising the step of performing dose correction for long-range effects, wherein the assigned dosages of at least two shots in the plurality of shaped beam shots differ from each other before the dose correction.

18. The method of claim 10 wherein the surface comprises a reticle to be used in an optical lithographic process to manufacture a substrate.

19. A method for manufacturing an integrated circuit using an optical lithographic process, the optical lithographic process using a reticle manufactured with charged particle beam lithography, the method comprising the steps of:

determining a plurality of shaped beam shots for an exposure pass; and

forming a pattern on the reticle, wherein the reticle has been coated with a resist, wherein a charged particle beam writer produces a dosage on the resist-coated reticle using the plurality of shaped beam shots, wherein the dosage on the resist-coated reticle forms the pattern, wherein the pattern on the reticle comprises a pattern perimeter, wherein the resist comprises a resist threshold,

wherein the plurality of shaped beam shots provides different dosages to different parts of the pattern, and wherein the step of determining comprises calculating a dose margin from the plurality of shaped beam shots, and wherein the dose margin is a slope of the resist dosage, at the resist threshold, with respect to a linear dimension perpendicular to the pattern perimeter.

20. The method of claim 19 wherein the calculating comprises charged particle beam simulation.

21. The method of claim 20 wherein the charged particle beam simulation includes at least one of a group consisting of forward scattering, backward scattering, resist diffusion, Coulomb effect, etching, fogging, loading and resist charging.

22. A system for fracturing or mask data preparation or proximity effect correction or optical proximity correction or mask process correction comprising:

a device configured to determine a plurality of shaped beam charged particle beam shots for an exposure pass, wherein the plurality of shaped beam shots, when used in a charged particle beam writer, produces a dosage on a resist-coated surface, wherein the dosage on the resist-coated surface forms a pattern on the surface, wherein the pattern on the surface comprises a pattern perimeter, wherein the resist comprises a resist threshold, wherein the plurality of shaped beam shots provides different dosages to different parts of the pattern, and wherein the device configured to determine calculates a dose margin from the plurality of shaped beam shots, and wherein the dose margin is a slope of the resist dosage, at the resist threshold, with respect to a linear dimension perpendicular to the pattern perimeter.

23. The system of claim 22 wherein the dose margin is optimized.

24. The system of claim 23 wherein the plurality of shaped beam shots produces a higher resist dosage peak near the pattern perimeter than in an interior area of the pattern on the surface.

25. The system of claim 22 wherein each shot in the plurality of shaped beam shots is a variable shaped beam (VSB) shot.