Method of pattern selection for source and mask optimization

• US 8,739,082 B2
• Filed: 10/26/2010
• Issued: 05/27/2014
• Est. Priority Date: 10/28/2009
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: Hong Chen, Hua-Yu Liu, Jiangwei Li, Jun Ye, Luoqi Chen, Min-Chun Tsai, Yen-Wen Lu, Youping Zhang, Zhi-Pan Li
• Inventors: Liu, Hua-Yu, Chen, Luoqi, Chen, Hong, Li, Zhi-Pan, Ye, Jun, Tsai, Min-Chun, Zhang, Youping, Lu, Yen-Wen, Li, Jiangwei
• Primary Examiner(s): Siek, Vuthe
• Application Number:
  US13/505,286
• Publication Number:
  US 20120216156A1
• Time in Patent Office: 1,309 Days
• Field of Search: 716/52, 716/53, 716/54, 716/55, 355/67
• US Class Current: 716/55
• 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 7/70125 Use of illumination settings tailored to particular mask patterns details of setting means G03F7/70091
• CPC Class Codes: G03F 7/70425 Imaging strategies, e.g. for increasing throughput or resolution, printing product fields larger than the image field or compensating lithography- or non-lithography errors, e.g. proximity correction, mix-and-match, stitching or double patterning
• CPC Class Codes: G03F 7/70441 Optical proximity correction [OPC]
• 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 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 30/398 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

Abstract

The present invention relates to a method of selecting a subset of patterns from a design, to a method of performing source and mask optimization, and to a computer program product for performing the method of selecting a subset of patterns from a design. According to certain aspects, the present invention enables coverage of the full design while lowering the computation cost by intelligently selecting a subset of patterns from a design in which the design or a modification of the design is configured to be imaged onto a substrate via a lithographic process. The method of selecting the subset of patterns from a design includes identifying a set of patterns from the design related to the predefined representation of the design. By selecting the subset of patterns according to the method, the selected subset of patterns constitutes a similar predefined representation of the design as the set of patterns.

Claims

1. A computer-implemented method of selecting a subset of patterns associated with a design, in which the design or a modification of the design is configured to be imaged onto a substrate via a lithographic process, and in which the subset of patterns constitutes a predefined representation of the design, the method comprising the steps of:

identifying a set of patterns related to the predefined representation of the design, grouping and/or ranking the set of patterns,

defining a threshold related to the grouping and/or ranking, and

selecting the subset of patterns from the set of patterns, wherein the subset comprises patterns from the set of patterns above or below the threshold,

wherein one or more of the steps are performed by a computer, and

wherein the step of identifying a set of patterns comprises the step of calculating diffraction order distributions for the patterns of the design, and

wherein the step of grouping and/or ranking the set of patterns comprises grouping the set of patterns into a plurality of groups based on the calculated diffraction order distributions, and

wherein the step of selecting the subset of patterns comprises selecting one or more patterns from the plurality of groups as the subset.

2. A computer-implemented method of selecting a subset of patterns associated with a design, in which the design or a modification of the design is configured to be imaged onto a substrate via a lithographic process, and in which the subset of patterns constitutes a predefined representation of the design, the method comprising the steps of:

identifying a set of patterns related to the predefined representation of the design,

grouping and/or ranking the set of patterns,

defining a threshold related to the grouping and/or ranking, and

selecting the subset of patterns from the set of patterns, wherein the subset comprises patterns from the set of patterns above or below the threshold,

wherein one or more of the steps are performed by a computer, and

wherein the step of identifying a set of patterns comprises identifying one or more memory patterns, and

wherein the method further comprises a step of pre-optimizing an illumination source of a lithographic tool for imaging the design onto the substrate for the one or more memory patterns, and

wherein the step of grouping and/or ranking the set of patterns comprises using the pre-optimized illumination source to determine potential hot-spots in the design, and

wherein the step of selecting the subset of patterns comprises selecting the subset based on the determined potential hot-spots.

3. A computer-implemented method of selecting a subset of:

patterns associated with a design, in which the design or a modification of the design is configured to be imaged onto a substrate via a lithographic process, and in which the subset of patterns constitutes a predefined representation of the design, the method comprising the steps of;

identifying a set of patterns related to the predefined representation of the design,

grouping and/or ranking the set of patterns,

defining a threshold related to the grouping and/or ranking, and

selecting the subset of patterns from the set of patterns, wherein the subset comprises patterns from the set of patterns above or below the threshold,

wherein one or more of the steps are performed by a computer, and

wherein the method further comprises a step of identifying an initial illumination source for the lithographic process, and

wherein the step of grouping and/or ranking the set of patterns comprises using the initial illumination source to determine potential hot-spots in the design, and

wherein the step of selecting the subset of patterns comprises selecting the subset based on the determined potential hot-spots.

4. A computer-implemented method of selecting a subset of patterns associated with a design, in which the design or a modification of the design is configured to be imaged onto a substrate via a lithographic process, and in which the subset of patterns constitutes a predefined representation of the design, the method comprising the steps of:

identifying a set of patterns related to the predefined representation of the design,

grouping and/or ranking the set of patterns,

defining a threshold related to the grouping and/or ranking, and

selecting the subset of patterns from the set of patterns, wherein the subset comprises patterns from the set of patterns above or below the threshold,

wherein one or more of the steps are performed by a computer, and

wherein the step of grouping and/or ranking the set of patterns comprises grouping patterns in the full set of clips by design type into a plurality of groups, and sorting the patterns in each group by pitch and feature type to determine an optimal pattern in each group; and

wherein the step of selecting the subset of patterns comprises selecting the optimal pattern in each group as the subset.

5. A computer-implemented method of selecting a subset of patterns associated with a design, in which the design or a modification of the design is configured to be imaged onto a substrate via a lithographic process, and in which the subset of patterns constitutes a predefined representation of the design, the method comprising the steps of:

identifying a set of patterns related to the predefined representation of the design,

grouping and/or ranking the set of patterns,

defining a threshold related to the grouping and/or ranking, and

selecting the subset of patterns from the set of patterns, wherein the subset comprises patterns from the set of patterns above or below the threshold,

wherein one or more of the steps are performed by a computer, and

wherein the method further comprises a step of identifying a simulation model of the lithographic process and using the model to estimate process parameter sensitivities for the patterns of the design; and

wherein the step of selecting the subset of patterns comprises selecting the subset based on the estimated process parameter sensitivities.

6. A computer-implemented method of selecting a subset of patterns associated with a design, in which the design or a modification of the design is configured to be imaged onto a substrate via a lithographic process, and in which the subset of patterns constitutes a predefined representation of the design, the method comprising the steps of:

identifying a set of patterns related to the predefined representation of the design,

grouping and/or ranking the set of patterns,

defining a threshold related to the grouping and/or ranking, and

selecting the subset of patterns from the set of patterns, wherein the subset comprises patterns from the set of patterns above or below the threshold,

wherein one or more of the steps are performed by a computer, and

performing a source and mask optimization method for imaging the design or a modification of the design onto the substrate via the lithographic process, wherein the source and mask optimization method includes;

obtaining an optimized source configuration based on the selected subset of patterns, the source configuration being a configuration of an illumination source of a lithographic tool used for the lithographic process; and

optimizing the design using the optimized source.

7. The method according to claim 6, wherein the source and mask optimization method initially performs steps of:

selecting an initial source configuration;

verifying a lithographic performance of the design when using the initial source configuration, wherein the step of verifying the lithographic performance comprises identifying hot-spots in the design, the hot-spots constituting patterns from the design which limit a lithographic parameter of the design;

and wherein the subset of patterns comprises at least one identified hot-spot.