# US 10,500,696 B2 · Method of detecting clogging of chuck table and processing apparatus

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- Number: US 10,500,696 B2
- Document ID: US10500696B2
- Status: Granted
- Kind: B2
- Application number: 15/872,175
- Filed: 2018-01-16
- Published: 2018-07-19
- Granted: 2019-12-10
- Earliest claimed: 2017-01-16
- Assignees: Disco Corporation
- Applicants: Disco Corporation
- Inventors: Hideki Matsui; Shigenori Harada
- Web page: https://patentgrep.com/patent/US10500696B2

## CPC

- B24B 49/12: involving optical means
- B24B 41/06: Work supports, e.g. adjustable steadies (B24B37/27 takes precedence)
- G06T 7/0004: {Industrial image inspection}
- G06T 7/0006: {using a design-rule based approach}
- B24B 7/228: {for grinding thin, brittle parts, e.g. semiconductors, wafers (grinding edges of thin, brittle parts B24B9/065)}
- G06T 2207/30148: Semiconductor; IC; Wafer
- B24B: MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING (grinding of gear teeth B23F, of screw-threads B23G1/36; by electro-erosion B23H; abrasive or related blasting B24C; tools for grinding, buffing or sharpening B24D; polishing compositions C09G1/00; abrasives C09K3/14; electrolytic etching or polishing C25F3/00; grinding arrangements for use on assembled railway tracks E01B31/17); DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL

## Abstract

A method of detecting clogging of a chuck table includes an imaging step of capturing an image of a holding surface of the chuck table while air and water are being ejected to the holding surface of the chuck table, an image processing step of binarizing the captured image into a binary image, and a decision step of deciding a clogged ratio of the chuck table on the basis of the binary image.

## Claims

### Claim 1

A method of detecting clogging of a chuck table for holding a workpiece under suction thereon, the method comprising:
an ejecting step of ejecting air and water through a holding surface of the chuck table;
an imaging step of capturing an image of the holding surface of the chuck table while the air and water are being ejected through the holding surface;
an image processing step of binarizing the captured image into a binary image; and
a decision step of determining a clogged ratio of the chuck table on the basis of the binary image, wherein said clogged ratio is a total area of clogged regions of the holding surface compared to a total area of the holding surface.

### Claim 2 (depends on 1)

The method of detecting clogging of a chuck table according to claim 1, further comprising:
a tolerance setting step of setting a tolerance for the clogged ratio of the chuck table; and
an error message being issued if the clogged ratio of the chuck table decided at the decision step exceeds the tolerance.

### Claim 3

A processing apparatus comprising:
a chuck table holding a workpiece under suction thereon, said chuck table including a holding surface and an ejector, said ejector being configured to eject air and water through the holding surface;
processing means for processing the workpiece;
imaging means for capturing an image of a holding surface of the chuck table while air and water are being ejected through the holding surface;
a binarizer configured for binarizing the captured image into a binary image; and
decision means for deciding a clogged ratio of the chuck table on the basis of the binary image, wherein said clogged ratio is a total area of clogged regions of the holding surface compared to a total area of the holding surface.

### Claim 4 (depends on 1)

The method of detecting clogging of a chuck table according to claim 1, wherein said imaging step includes capturing an image of the holding surface at each of a plurality of predetermined time intervals thereby producing a plurality of successive captured images of the holding surface, and wherein said image processing step produces a plurality of binary images based on the plurality of successive captured images.

### Claim 5 (depends on 2)

The method of detecting clogging of a chuck table according to claim 2, further comprising replacing the chuck table with another chuck table after the error message is issued.

### Claim 6 (depends on 2)

The method of detecting clogging of a chuck table according to claim 2, further comprising grinding the holding surface of the chuck table to remove the clogged regions after the error message is issued.

### Claim 7 (depends on 2)

The method of detecting clogging of a chuck table according to claim 2, wherein the tolerance of the clogged ratio is set at 40%.

### Claim 8 (depends on 3)

The apparatus according to claim 3, wherein the clogged ratio is set at 40%.