# US 12,217,966 B2 · Processing method of wafer, protective sheet, and protective sheet laying method

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- Number: US 12,217,966 B2
- Document ID: US12217966B2
- Status: Granted
- Kind: B2
- Application number: 17/381,784
- Filed: 2021-07-21
- Published: 2022-02-03
- Granted: 2025-02-04
- Earliest claimed: 2020-07-29
- Assignees: Disco Corporation
- Applicants: Disco Corporation
- Inventors: Kazuma Sekiya
- Web page: https://patentgrep.com/patent/US12217966B2

## CPC

- H10P 52/00: Grinding, lapping or polishing of wafers, substrates or parts of devices
- H10P 72/7402: {Wafer tapes, e.g. grinding or dicing support tapes}
- H10P 54/00: Cutting or separating of wafers, substrates or parts of devices
- H10P 72/7404: {the wafer tape being a laminate of three or more layers, e.g. including additional layers beyond a base layer and an uppermost adhesive layer}
- H10P 90/123: {by grinding or lapping}
- H10P 72/7416: {used during dicing or grinding}
- H10P 72/7422: {used to protect an active side of a device or wafer}
- H10W 72/07533: {Ultrasonic bonding, e.g. thermosonic bonding}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

There is provided a processing method of a wafer. The processing method includes a protective sheet preparation step of preparing a protective sheet including a first sheet that is thermocompression-bonded to a surface of the wafer by heating, a second sheet that is laid on the first sheet and has fluidity due to the heating, and a third sheet that is laid on the second sheet and keeps flatness even with the heating. The processing method also includes a protective sheet laying step of causing a side of the first sheet to face a front surface of the wafer and executing heating to execute thermocompression bonding to lay the protective sheet on the front surface of the wafer and a grinding step of causing a side of the protective sheet to be held by a holding surface of a chuck table and grinding a back surface of the wafer.

## Claims

### Claim 1

A protective sheet laid on a surface of a wafer, the protective sheet comprising:
a first sheet that is thermocompression-bonded directly to the surface of the wafer by heating, wherein the first sheet is a polypropylene sheet;
a second sheet that is laid on the first sheet and has fluidity due to the heating; and
a third sheet that is laid on the second sheet and is allowed to keep flatness even with the heating;
wherein the first sheet, the second sheet and the third sheet are thermocompression bonded to become a three layer protective sheet.

### Claim 2 (depends on 1)

The protective sheet according to claim 1, wherein:
the second sheet is configured by a polyolefin-based resin, and the third sheet is configured by a polyester-based resin.

### Claim 3 (depends on 2)

The protective sheet according to claim 2, wherein:
the second sheet is configured by polyethylene, and the third sheet is configured by polyethylene terephthalate.

### Claim 4 (depends on 1)

The protective sheet according to claim 1, wherein:
melting temperatures of the first sheet and the second sheet are lower than the third sheet.

### Claim 5 (depends on 4)

The protective sheet according to claim 4, wherein:
the melting temperature of the second sheet is less than the melting temperature of the first sheet.

### Claim 6 (depends on 1)

The protective sheet according to claim 1, wherein:
a heating temperature to execute the heating during the thermocompression bonding is higher than a melting temperature of the second sheet and lower than a melting temperature of the third sheet.

### Claim 7 (depends on 1)

The protective sheet according to claim 1, wherein:
a melting temperature of the second sheet is between 120° C. to 140° C.

### Claim 8 (depends on 1)

The protective sheet according to claim 1, wherein:
a melting temperature of the first sheet is between 160° C. to 180° C.