Method and system for forming patterns using charged particle beam lithography

• US 9,400,857 B2
• Filed: 04/15/2013
• Issued: 07/26/2016
• Est. Priority Date: 09/19/2011
• Status: Active Grant

• Current Assignee: D2S, Inc.
• Original Assignee: D2S, Inc.
• Inventors: Fujimura, Akira, Aadamov, Anatoly, Khaliullin, Eldar, Bork, Ingo
• Primary Examiner(s): Parihar, Suchin
• Application Number:
  US13/862,475
• Publication Number:
  US 20130283219A1
• Time in Patent Office: 1,198 Days
• Field of Search: 716/100, 716/53
• US Class Current: 1/1
• 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: G06F 30/00 Computer-aided design [CAD]
• CPC Class Codes: G06F 30/20 Design optimisation, verification or simulation optimisation, verification or simulation of circuit designs G06F30/30
• CPC Class Codes: G06F 30/367 Design verification, e.g. using simulation, simulation program with integrated circuit emphasis [SPICE], direct methods or relaxation methods
• CPC Class Codes: G06F 30/39 Circuit design at the physical level physical level design for reconfigurable circuits G06F30/347

Abstract

A method for mask data preparation (MDP) is disclosed, in which a set of shots is determined that will form a pattern on a reticle, where the determination includes calculating the pattern that will be formed on a substrate using an optical lithographic process with a reticle formed using the set of shots. A method for optical proximity correction (OPC) or MDP is also disclosed, in which a preliminary set of charged particle beam shots is generated using a preliminary mask model, and then the shots are modified by calculating both a reticle pattern using a final mask model, and a resulting substrate pattern. A method for OPC is also disclosed, in which an ideal pattern for a photomask is calculated from a desired substrate pattern, where the model used in the calculation includes only optical lithography effects and/or substrate processing effects.

Claims

1. A method for optical proximity correction (OPC) comprising:

inputting a desired pattern for a substrate to be manufactured using an optical lithographic process with a photomask;

inputting a substrate model for transferring a pattern from the photomask to the substrate using the optical lithographic process, wherein the substrate model has been determined using a pre-existing mask model for forming a pattern on the photomask using charged particle beam lithography, wherein effects which are included in the mask model are excluded from the substrate model; and

calculating an ideal pattern for the photomask from the desired pattern for the substrate using the substrate model, wherein the calculating is performed using a computing hardware device.

2. The method of claim 1, wherein in determination of the substrate model, mask effects have been calculated using the pre-existing mask model and have been subtracted from a calibration process for the substrate model.

12. The method of claim 1 wherein the mask model includes at least one effect selected from the group consisting of forward scattering, backward scattering, Coulomb effect, fogging, loading and reticle resist charging.

3. A method for optical proximity correction (OPC), the method comprising:

determining a mask model for forming a reticle pattern on a reticle with charged particle beam lithography, wherein the reticle is to be used in an optical lithographic process to transfer the reticle pattern to a substrate, wherein the mask model includes at least one effect selected from the group consisting of forward scattering, backward scattering, Coulomb effect, fogging, loading and reticle resist charging; and

determining a substrate model for transferring the reticle pattern to the substrate using optical lithography, wherein the mask model is used in determining the substrate model, and wherein the substrate model excludes the effects which are included in the mask model, wherein at least one of the determining of a mask model and the determining of a substrate model is performed using a computing hardware device.

4. The method of claim 3 wherein the mask model includes at least one effect selected from the group consisting of reticle resist bake, reticle resist development and reticle etch.

5. The method of claim 3 wherein in determining the substrate model, mask effects are calculated using the mask model and are subtracted from a calibration process for the substrate model.

6. The method of claim 3, further comprising:

inputting a desired substrate pattern for the substrate; and

determining a desired reticle pattern for the reticle from the desired substrate pattern, using the substrate model.

7. The method of claim 6 wherein determining the desired reticle pattern comprises using inverse lithography technology (ILT), and wherein the ILT excludes rectilinearization.

8. The method of claim 7 wherein the desired reticle pattern comprises one or more complex shapes, wherein the complex shape comprises a polygon with non-manhattan, non-45 degree edges.

9. The method of claim 8, further comprising:

determining a set of charged particle beam shots which is capable of forming the desired reticle pattern on the reticle, within a predetermined tolerance.

10. The method of claim 9 wherein determining the set of charged particle beam shots comprises calculating a calculated pattern that the set of shots will form on the reticle, wherein the calculating uses the mask model.

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