# US 2008/0187842 A1 · Method and System For Wafer Inspection

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- Number: US 2008/0187842 A1
- Document ID: US20080187842A1
- Status: Published application
- Kind: A1
- Application number: 11/671,772
- Filed: 2007-02-06
- Published: 2008-08-07
- Earliest claimed: 2007-02-06
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Inventors: Chang-Cheng Hung; Tsai-Sheng Gau
- Web page: https://patentgrep.com/patent/US20080187842A1

## CPC

- G03F 1/84: Inspecting
- G06T 7/001: {using an image reference approach}
- G06T 2207/10056: Microscopic image
- G06T 2207/30148: Semiconductor; IC; Wafer
- 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)
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL

## Abstract

A method for inspecting semiconductor wafers patterned by a photomask includes loading a first wafer and scanning a first image of the first wafer, loading a second wafer and scanning a second image of the second wafer, comparing the first and second images, and classifying a difference detected between the first and second images as a potential defect on the photomask. The potential defect includes a haze defect on the photomask.

## Claims

### Claim 1

A method for inspecting semiconductor wafers patterned by a photomask, the method comprising:
loading a first wafer and scanning a first image on the first wafer;
loading a second wafer and scanning a second image on the second wafer;
comparing the first and second images; and
classifying a difference detected between the first and second images as a potential defect on the photomask.

### Claim 2 (depends on 1)

The method of claim 1, wherein the first wafer is patterned with the photomask that was inspected to be substantially free of defects.

### Claim 3 (depends on 2)

The method of claim 2, wherein the second wafer is patterned with the same photomask at a time after patterning of the first wafer.

### Claim 4 (depends on 1)

The method of claim 1, wherein the loading and scanning the first and second wafers are performed by an optical imaging system.

### Claim 5 (depends on 1)

The method of claim 1, wherein the loading and scanning the first and second wafers are performed after a developing inspection of the first and second wafers.

### Claim 6 (depends on 1)

The method of claim 1, wherein the loading and scanning the first and second wafers are performed after an etching inspection of the first and second wafers.

### Claim 7 (depends on 1)

The method of claim 1, wherein the loading and scanning the first and second wafers are performed after a stripping inspection of the first and second wafers.

### Claim 8 (depends on 1)

The method of claim 1, further comprising:
disqualifying the photomask; and
sending the photomask for inspection.

### Claim 9 (depends on 1)

The method of claim 1, wherein the comparing includes running an algorithm to detect the difference between the first and second images.

### Claim 10 (depends on 1)

The method of claim 1, wherein the classifying includes classifying the difference as a haze defect on the photomask.

### Claim 11

An system, comprising:
a first wafer inspector for generating an image of a first wafer;
a second wafer inspector for generating an image of a second wafer; and
a comparator coupled to the first wafer inspector and a second wafer inspector via a data bus;
wherein the comparator is configured and operable to receive the images of the first and second wafer via the data bus, compare the images of the first and second wafer, and classify a difference detected in the image of the second wafer with respect to the image of the first wafer resulting from the comparison.

### Claim 12 (depends on 11)

The system of claim 11, wherein the first and second wafer inspectors include a stand alone wafer defect inspection tool.

### Claim 13 (depends on 12)

The system of claim 12, wherein the stand alone wafer defect inspection tool includes an optical imaging system.

### Claim 14 (depends on 13)

The system of claim 13, wherein the optical imaging system includes a single objective lens system.

### Claim 15 (depends on 13)

The system of claim 13, wherein the optical imaging system includes a multiple objective lens system.

### Claim 16

A method, comprising:
patterning a first wafer and a second wafer;
generating an image of the patterned first wafer and an image of the patterned second wafer;
comparing the images of the first and second wafer; and
classifying a difference detected in the image of the second wafer with respect to the image of the first wafer resulting from the comparing step.

### Claim 17 (depends on 16)

The method of claim 16, wherein the patterning includes patterning the first wafer with a first process and the second wafer with a second process.

### Claim 18 (depends on 17)

The method of claim 17, wherein the classifying the difference includes evaluating the first process and the second process to determine which process is better suited for the patterning step.

### Claim 19 (depends on 16)

The method of claim 16, wherein the classifying the difference includes identifying a haze defect on a photomask that was used to pattern the first and second wafers.

### Claim 20 (depends on 19)

The method of claim 19, further comprising inspecting and cleaning the photomask.