# US 9,518,932 B2 · Metrology optimized inspection

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- Number: US 9,518,932 B2
- Document ID: US9518932B2
- Status: Granted
- Kind: B2
- Application number: 14/517,751
- Filed: 2014-10-17
- Published: 2015-05-07
- Granted: 2016-12-13
- Earliest claimed: 2013-11-06
- Assignees: KLA-Tencor Corporation
- Applicants: KLA-Tencor Corporation
- Inventors: Allen Park; Craig MacNaughton; Ellis Chang
- Web page: https://patentgrep.com/patent/US9518932B2

## CPC

- G01N 21/93: Detection standards; Calibrating {baseline adjustment, drift correction}
- G01B 11/0675: {using interferometry}
- G01N 21/9501: {Semiconductor wafers (manufacturing processes per se of semiconductor devices implementing a measuring step H10P74/20)}
- G01N 21/956: Inspecting patterns on the surface of objects {(contactless testing of electronic circuits G01R31/308; testing currency G07D; manufacturing processes per se of semiconductor devices implementing a measuring step H10P74/20)}
- G03F 7/705: {Modelling or simulating from physical phenomena up to complete wafer processes or whole workflow in wafer productions}
- G03F 7/70616: {Monitoring the printed patterns}
- G01B 11/06: for measuring thickness {; e.g. of sheet material (thickness measurement by thermal means G01B21/085)}
- G01B 2210/56: Measuring geometric parameters of semiconductor structures, e.g. profile, critical dimensions or trench depth
- G01N 2201/061: Sources
- G01N 2201/105: Purely optical scan
- G01N 2201/11: Monitoring and controlling the scan
- G01N 2201/125: Digital circuitry
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G)

## Abstract

Methods and systems for determining one or more parameters of a wafer inspection process are provided. One method includes acquiring metrology data for a wafer generated by a wafer metrology system. The method also includes determining one or more parameters of a wafer inspection process for the wafer or another wafer based on the metrology data.

## Claims

### Claim 1

A computer-implemented method for determining one or more parameters of a wafer inspection process, comprising:
acquiring metrology data for a wafer generated by a wafer metrology system, wherein the wafer metrology system performs measurements on the wafer thereby generating the metrology data, and wherein acquiring the metrology data comprises acquiring the metrology data from a storage medium in which the metrology data has been stored by the wafer metrology system;and
determining one or more parameters of a wafer inspection process for the wafer or another wafer based on the metrology data, wherein said acquiring and said determining are performed by a computer system, wherein the computer system comprises one or more processors and executes instructions from a memory medium, wherein the wafer inspection process is performed to detect defects on the wafer or the other wafer, and wherein determining the one or more parameters comprises:
determinining a probability of critical dimension variation in one or more areas of the wafer or the other wafer based on the metrology data;
determining at least one of the one or more areas in which the probability is higher than other of the one or more areas; and
determining the one or more parameters such that the at least one of the one or more areas is sampled by a wafer inspection system that performs the wafer inspection process more heavily than the other of the one or more areas.

### Claim 2 (depends on 1)

The method of claim 1, Wherein the metrology data comprises information for warp of the wafer.

### Claim 3 (depends on 1)

The method of claim 1, wherein the metrology data comprises information for bow of the wafer.

### Claim 4 (depends on 1)

The method of claim 1, wherein the metrology data comprises a thickness of a film formed on the wafer.

### Claim 5 (depends on 1)

The method of claim 1, wherein the metrology data comprises a critical dimension of a patterned structure formed on the wafer.

### Claim 6 (depends on 1)

The method of claim 1, wherein the one or more parameters of the wafer inspection process that are determined for the one or more areas on the wafer or the other wafer are different from the one or more parameters determined for one or more other areas on the wafer or the other wafer.

### Claim 7 (depends on 1)

The method of claim 1, wherein the one or more parameters of the wafer inspection process comprise one or more parameters of defect detection performed during the wafer inspection process.

### Claim 8 (depends on 1)

The method of claim 1, wherein the one or more parameters of the wafer inspection process comprise one or more parameters that at least partially determine a sensitivity of defect detection performed for the one or more areas of the wafer or the other wafer.

### Claim 9 (depends on 1)

The method of claim 1, wherein the one or more parameters of the wafer inspection process comprise one or more parameters of defect sampling performed during the wafer inspection process.

### Claim 10 (depends on 1)

The method of claim 1, wherein the one or more parameters of the wafer inspection process comprise a selection of the one or more areas on the wafer or the other wafer at which output is generated by the wafer inspection system during the wafer inspection process.

### Claim 11 (depends on 1)

The method of claim 1, wherein determining the one or more parameters further comprises:
selecting one or more die on the wafer or the other wafer based on the metrology data;
acquiring output generated by the wafer inspection system for the e or more selected die; and
generating a reference die from the output generated by the wafer inspection system for the one or more selected die, wherein the reference die is used in the wafer inspection process to detect the defects on the wafer or the other wafer.

### Claim 12 (depends on 1)

The method of claim 1, wherein determining the one or more parameters of the wafer inspection process further comprises:
determining, based on one or more first parameters of the wafer inspection process and the metrology data, which one or more areas on the wafer or the other wafer will produce more noise than other areas on the wafer or the other wafer in the wafer inspection process and which one or more additional areas on the wafer or the other wafer will produce less noise than other areas on the wafer or the other wafer; and
determining one or more second parameters of the wafer inspection process based on the one or more areas that will produce more noise than the other areas and the one or more additional areas.

### Claim 13 (depends on 12)

The method of claim 12, wherein the one or more second parameters comprise one or more defect sampling parameters, and wherein the one or more defect sampling parameters are determined to preferentially select random defects in the one or more additional areas that will produce less noise than the other areas.

### Claim 14 (depends on 12)

The method of claim 12, wherein the one or more second parameters comprise one or more defect sampling parameters, and wherein the one or more defect sampling parameters are determined to preferentially select systematic defects in the one or more areas that will produce more noise than the other areas.

### Claim 15 (depends on 1)

The method of claim 1, further comprising acquiring metrology or inspection data for a reticle, wherein the reticle is used to print patterned features on the wafer, and wherein determining the one or more parameters of the wafer inspection process is performed based on the metrology data for the wafter in combination with the metrology or inspection data for the reticle.

### Claim 16 (depends on 1)

The method of claim 1, wherein the one or more parameters comprise one or more additional areas of the wafer or the other wafer used for field-to-field inspection performed within dies during the wafer inspection process.

### Claim 17 (depends on 1)

The method of claim 1, further comprising determining one or more parameters of a fabrication process for the wafer or the other wafer based on the metrology data, wherein the wafer inspection process is further performed on the wafer or the other wafer after the fabrication process is performed on the wafer or the other wafer, and wherein determining the one or more parameters of the wafer inspection process is performed based on the metrology data for the wafer in combination with the one or more parameters of the fabrication process.

### Claim 18 (depends on 1)

The method of claim 1, wherein determining the one or more parameters further comprises determining one or more characteristics of noise in output generated for one or more additional areas of the wafer or the other wafer by the wafer inspection system during the wafer inspection process based on the metrology data and determining one or more parameters of output noise reduction performed during the wafer inspection process based on the one or more determined characteristics of the noise.

### Claim 19

A non-transitory computer-readable medium, storing program instructions executable on a computer system for performing a computer-implemented method for determining one or more parameters of a wafer inspection process, wherein the computer-implemented method comprises:
acquiring metrology data for a wafer generated by a wafer metrology system, wherein the wafer metrology system performs measurements on the wafer thereby generating the metrology data, and wherein acquiring the metrology data comprises acquiring the metrology data from a storage medium in which the metrology data has been stored by the wafer metrology system; and
determining one or more parameters of a wafer inspection process for the wafer or another wafer based on the metrology data, wherein the computer system comprises one or more processors and executes the program instructions from the non-transitory computer-readable medium, wherein the wafer inspection process is performed to detect defects on the wafer or the other wafer, and wherein determining the one or more parameters comprises:
determining a probability of critical dimension variation in one or more areas of the wafer or the other wafer based on the metrology data;
determining at least one of the one or more areas in which the probability is higher than other of the one or more areas; and
determining the one or more parameters such that the at least one of the one or more areas is sampled by a wafer inspection system that performs the wafer inspection process more heavily than the other of the one or more areas.

### Claim 20

A system configured to determine one or more parameters of a wafer inspection process, comprising:
an inspection subsystem configured to generate output for a wafer by scanning a wafer with light and detecting light from the wafer during the scanning, wherein the inspection subsystem comprises at least a light source and a detector, and wherein the inspection subsystem scans light from the light source over the wafer, and wherein the detector detects the light from the wafer during the scanning; and
a computer subsystem configured for:
acquiring metrology data for the wafer generated by a wafer metrology system, wherein the wafer metrology system performs measurements on the wafer thereby generating the metrology data, and wherein acquiring the metrology data comprises acquiring the metrology data from a storage medium in which the metrology data has been stored by the wafer metrology system; and
determining one or more parameters of a wafer inspection process for the wafer or another wafer based on the metrology data, wherein the computer subsystem comprises one or more processors and executes instructions from a memory medium, wherein the wafer inspection process is performed with the inspection subsystem and the one or more determined parameters to detect defects on the wafer or the other wafer, and wherein determining the one or more parameters comprises:
determining a probability of critical dimension variation in one or more areas of the wafer or the other wafer based on the metrology data:
determining at least one of the one or more areas in which the probability is higher than other of the one or more areas; and
determining the one or more parameters such that the at least one of the one or more areas is sampled by the inspection subsystem that performs the wafer inspection process more heavily than the other of the one or more areas.

### Claim 21 (depends on 20)

The system of claim 20, wherein the metrology data comprises information for warp of the wafer.

### Claim 22 (depends on 20)

The system of claim 20, wherein the metrology data comprises information for bow of the wafer.

### Claim 23 (depends on 20)

The system of claim 20, wherein the metrology data comprises a thickness of a film formed on the wafer.

### Claim 24 (depends on 20)

The system of claim 20, wherein the metrology data comprises a critical dimension of a patterned structure formed on the wafer.

### Claim 25 (depends on 20)

The system of claim 20, wherein the one or more parameters of the wafer inspection process that are determined for the one or more areas on the wafer or the other wafer are different from the one or more parameters determined for one or more other areas on the wafer or the other wafer.

### Claim 26 (depends on 20)

The system of claim 20, wherein the one or more parameters of the wafer inspection process comprise one or more parameters of defect detection performed during the wafer inspection process.

### Claim 27 (depends on 20)

The system of claim 20, wherein the one or more parameters of the wafer inspection process comprise one or more parameters that at least partially determine a sensitivity of defect detection performed for the one or more areas of the wafer or the other wafer.

### Claim 28 (depends on 20)

The system of claim 20, wherein the one or more parameters of the wafer inspection process comprise one or more parameters of defect sampling performed during the wafer inspection process.

### Claim 29 (depends on 20)

The system of claim 20, wherein the one or more parameters of the wafer inspection process comprise a selection of the one or more areas on the wafer or the other wafer at which output is generated by the inspection subsystem during the wafer inspection process.

### Claim 30 (depends on 20)

The system of claim 20, wherein determining the one or more parameters further comprises:
selecting one or more die on the wafer or the other wafer based on the metrology data;
acquiring output generated by the inspection subsystem for the one or more selected die; and
generating a reference die from the output generated by the inspection subsystem for the one or more selected die, wherein the reference die is used in the wafer inspection process to detect the defects on the wafer or the other wafer.

### Claim 31 (depends on 20)

The system of claim 20, wherein determining the one or more parameters of the wafer inspection process further comprises:
determining, based on one or more first parameters of the wafer inspection process and the metrology data, which one or more areas on the wafer or the other wafer will produce more noise than other areas on the wafer or the other wafer in the wafer inspection process and which one or more additional areas on the wafer or the other wafer will produce less noise than other areas on the wafer or the other wafer; and
determining one or more second parameters of the wafer inspection process based on the one or more areas that will produce more noise than the other areas and the one or more additional areas.

### Claim 32 (depends on 31)

The system of claim 31, wherein the one or more second parameters comprise one or more defect sampling parameters, and wherein the one or more defect sampling parameters are determined to preferentially select random defects in the one or more additional areas that will produce less noise than the other areas.

### Claim 33 (depends on 31)

The system of claim 31, wherein the one or more second parameters comprise one or more defect sampling parameters, and wherein the one or more defect sampling parameters are determined to preferentially select systematic defects in the one or more areas that will produce more noise than the other areas.

### Claim 34 (depends on 20)

The system of claim 20, wherein the computer subsystem is further configured for acquiring metrology or inspection data for a reticle, wherein the reticle is used to print patterned features on the wafer, and wherein determining the one or more parameters of the wafer inspection process is performed based on the metrology data for the wafer in combination with the metrology or inspection data for the reticle.

### Claim 35 (depends on 20)

The system of claim 20, wherein the one or more parameters comprise one or more additional areas of the wafer or the other wafer used for field-to-field inspection performed within dies during the wafer inspection process.

### Claim 36 (depends on 20)

The system of claim 20, wherein the computer subsystem is further configured for determining one or more parameters of a fabrication process for the wafer or the other wafer based on the metrology data, wherein the wafer inspection process is further performed on the wafer or the other wafer after the fabrication process is performed on the wafer or the other wafer, and wherein determining the one or more parameters of the water inspection process is performed based on the metrology data for the wafer in combination with the one or more parameters of the fabrication process.

### Claim 37 (depends on 20)

The system of claim 20, wherein determining the one or more parameters further comprises determining one or more characteristics of noise in output generated for one or more additional areas of the wafer or the other wafer by the inspection subsystem during the wafer inspection process based on the metrology data and determining one or more parameters of output noise reduction performed during the wafer inspection process based on the one or more determined characteristics of the noise.