Method of manufacturing reliability checking and verification for lithography process using a calibrated eigen decomposition model

• US 7,342,646 B2
• Filed: 01/27/2005
• Issued: 03/11/2008
• Est. Priority Date: 01/30/2004
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Masktools B.V. (ASML Holding NV)
• Inventors: Chen, Jang Fung, Shi, Xuelong
• Primary Examiner(s): Lee; Diane I.
• Assistant Examiner(s): LIU, MICHAEL
• Application Number:
  US11/051,559
• Publication Number:
  US 20050210437A1
• Time in Patent Office: 1,139 Days
• Field of Search: 355/77, 355/52, 355/53, 355/55, 430/5, 430/30
• US Class Current: 355/77
• 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 1/44 Testing or measuring features, e.g. grid patterns, focus monitors, sawtooth scales or notched scales
• CPC Class Codes: G03F 1/68 Preparation processes not covered by groups G03F1/20 - G03F1/50
• 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 7/705 Modelling or simulating from physical phenomena up to complete wafer processes or whole workflow in wafer productions
• CPC Class Codes: G03F 7/70516 Calibration of components of the microlithographic apparatus, e.g. light sources, addressable masks or detectors
• CPC Class Codes: G03F 7/70525 Controlling normal operating mode, e.g. matching different apparatus, remote control or prediction of failure
• 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 30/398 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: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

A method for modeling a photolithography process which includes the steps of generating a calibrated model of the photolithography process capable of estimating an image to be produced by the photolithography process when utilized to image a mask pattern containing a plurality features; and determining an operational window of the calibrated model, which defines whether or not the calibrated model can accurately estimate the image to be produced by a given feature in the mask pattern.

Claims

1. A method for modeling a photolithography process comprising the steps of:

generating a calibrated model of said photolithography process, said calibrated model capable of estimating an image to be produced by said photolithography process when utilized to image a mask pattern containing a plurality of features;

determining an operational window of said calibrated model, said operational window defining if said calibrated model can accurately estimate the image to be produced by a given feature in said mask pattern,

comparing said plurality of features of said mask pattern to said operational window of said calibrated model, and

identifying said plurality of features of said mask pattern that are not within the operational window of said calibrated model.

2. The method of claim 1, wherein said step of generating a calibrated model comprises the steps of:

defining an imaging system and processing conditions to be utilized in said photolithography process;

generating an initial model of said system and processing conditions of said photolithography process;

defining a plurality of test structures;

imaging the test structures utilizing said imaging system and processing conditions of said photolithography process to obtain actual imaging results;

generating simulated imaging results by subjecting said test structures to said model;

comparing said simulated imaging results to said actual imaging results; and

adjusting said initial model such that the difference between said simulated imaging results and said actual imaging results is less than a predefined criteria,

wherein said adjusted initial model corresponds to said calibrated model.

3. The method of claim 2, wherein said initial model and said calibrated model utilize eigen functions to represent said photolithography process.

4. The method of claim 2, wherein said comparing said simulated imaging results to said actual imaging results utilizes two-dimensional contour patterns in the comparison process.

5. A computer readable medium configured to store program instructions for execution by at least one programmable computer, wherein execution of the program instructions by at least one programmable computer causes the at least one programmable computer to perform a sequence of steps for modeling a photolithography process, said sequence of steps comprising:

generating a calibrated model of said photolithography process, said calibrated model capable of estimating an image to be produced by said photolithography process when utilized to image a mask pattern containing a plurality of features;

determining an operational window of said calibrated model, said operational window defining if said calibrated model can accurately estimate the image to be produced by a given feature in said mask pattern,

comparing said plurality of features of said mask pattern to said operational window of said calibrated model, and

identifying said plurality of features of said mask pattern that are not within the operational window of said calibrated model.

6. The computer readable medium of claim 5, wherein said step of generating a calibrated model comprises the steps of:

defining an imaging system and processing conditions to be utilized in said photolithography process;

generating an initial model of said system and processing conditions of said photolithography process;

defining a plurality of test structures;

imaging the test structures utilizing said imaging system and processing conditions of said photolithography process to obtain actual imaging results;

generating simulated imaging results by subjecting said test structures to said model;

comparing said simulated imaging results to said actual imaging results; and

adjusting said initial model such that the difference between said simulated imaging results and said actual imaging results is less than a predefined criteria,

wherein said adjusted initial model corresponds to said calibrated model.

7. The computer readable medium of claim 6, wherein said initial model and said calibrated model utilize eigen functions to represent said photolithography process.

8. The computer readable medium of claim 5, wherein said comparing said simulated imaging results to said actual imaging results utilizes two-dimensional contour patterns in the comparison process.

9. An apparatus for modeling a photolithography process, said apparatus comprising:

means for generating a calibrated model of said photolithography process, said calibrated model capable of estimating an image to be produced by said photolithography process when utilized to image a mask pattern containing a plurality of features;

means for determining an operational window of said calibrated model, said operational window defining if said calibrated model can accurately estimate the image to be produced by a given feature in said mask pattern,

means for comparing said plurality of features of said mask pattern to said operational window of said calibrated model, and

means for identifying said plurality of features of said mask pattern that are not within the operational window of said calibrated model.

10. The apparatus of claim 9, wherein said means for generating a calibrated model comprises:

means for defining an imaging system and processing conditions to be utilized in said photolithography process;

means for generating an initial model of said system and processing conditions of said photolithography process;

means for defining a plurality of test structures;

means for imaging the test structures utilizing said imaging system and processing conditions of said photolithography process to obtain actual imaging results;

means for generating simulated imaging results by subjecting said test structures to said model;

means for comparing said simulated imaging results to said actual imaging results; and

means for adjusting said initial model such that the difference between said simulated imaging results and said actual imaging results is less than a predefined criteria,

wherein said adjusted initial model corresponds to said calibrated model.

11. The apparatus of claim 10, wherein said initial model and said calibrated model utilize eigen functions to represent said photolithography process.

12. The apparatus of claim 10, wherein said comparing said simulated imaging results to said actual imaging results utilizes two-dimensional contour patterns in the comparison process.