# US 2020/0286784 A1 · Wafer processing method

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- Number: US 2020/0286784 A1
- Document ID: US20200286784A1
- Status: Published application
- Kind: A1
- Application number: 16/799,161
- Filed: 2020-02-24
- Published: 2020-09-10
- Earliest claimed: 2019-03-05
- Assignees: Disco Corporation
- Applicants: Disco Corporation
- Inventors: Shigenori HARADA; Minoru MATSUZAWA; Hayato KIUCHI; Yoshiaki YODO; Taro ARAKAWA; Masamitsu AGARI; Emiko KAWAMURA; Yusuke FUJII; Toshiki MIYAI; Makiko OHMAE
- Web page: https://patentgrep.com/patent/US20200286784A1

## CPC

- H10P 54/00: Cutting or separating of wafers, substrates or parts of devices
- B23K 26/364: for making a groove or trench, e.g. for scribing a break initiation groove
- B23K 26/40: taking account of the properties of the material involved
- C09J 7/241: {Polyolefin, e.g.rubber}
- 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 72/7414: {the auxiliary support including means facilitating the selective separation of some of a plurality of devices from the auxiliary support}
- H10P 72/7416: {used during dicing or grinding}
- H10P 72/7422: {used to protect an active side of a device or wafer}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- C09J: ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES (preparation of glue or gelatine C09H)

## Abstract

A wafer processing method includes a polyolefin sheet providing step of positioning a wafer in an inside opening of a ring frame and providing a polyolefin sheet on a back side or a front side of the wafer and on a back side of the ring frame, a uniting step of heating the polyolefin sheet as applying a pressure to the polyolefin sheet to thereby unite the wafer and the ring frame through the polyolefin sheet by thermocompression bonding, a dividing step of applying a laser beam to the wafer to form modified layers in the wafer, thereby dividing the wafer into individual device chips, and a pickup step of picking up each device chip from the polyolefin sheet.

## Claims

### Claim 1

A wafer processing method for dividing a wafer along a plurality of division lines to obtain a plurality of individual device chips, the division lines being formed on a front side of the wafer to thereby define a plurality of separate regions where a plurality of devices are individually formed, the wafer processing method comprising:
a ring frame preparing step of preparing a ring frame having an inside opening for accommodating the wafer;
a polyolefin sheet providing step of positioning the wafer in the inside opening of the ring frame and providing a polyolefin sheet on a back side or the front side of the wafer and on a back side of the ring frame;
a uniting step of heating the polyolefin sheet as applying a pressure to the polyolefin sheet after performing the polyolefin sheet providing step, thereby uniting the wafer and the ring frame through the polyolefin sheet by thermocompression bonding to form a frame unit in a condition where the front side of the wafer and the front side of the ring frame are exposed upward;
a dividing step of positioning a focal point of a laser beam inside the wafer, the laser beam having a transmission wavelength to the wafer, and applying the laser beam to the wafer along each division line, thereby forming a modified layer in the wafer along each division line to divide the wafer into the individual device chips, after performing the uniting step; and
a pickup step of picking up each device chip from the polyolefin sheet after performing the dividing step.

### Claim 2 (depends on 1)

The wafer processing method according to claim 1, wherein the uniting step includes a step of applying infrared light to the polyolefin sheet, thereby performing the thermocompression bonding.

### Claim 3 (depends on 1)

The wafer processing method according to claim 1, wherein the polyolefin sheet is larger in size than the ring frame, and the uniting step includes an additional step of cutting the polyolefin sheet after heating the polyolefin sheet, thereby removing a part of the polyolefin sheet outside an outer circumference of the ring frame.

### Claim 4 (depends on 1)

The wafer processing method according to claim 1, wherein the pickup step includes a step of expanding the polyolefin sheet to thereby increase a spacing between any adjacent ones of the device chips, and each device chip is pushed up through the polyolefin sheet.

### Claim 5 (depends on 1)

The wafer processing method according to claim 1, wherein the polyolefin sheet is formed of a material selected from the group consisting of polyethylene, polypropylene, and polystyrene.

### Claim 6 (depends on 5)

The wafer processing method according to claim 5, wherein the polyolefin sheet is formed of polyethylene, and the polyolefin sheet is heated in the range of 120° C. to 140° C. in the uniting step.

### Claim 7 (depends on 5)

The wafer processing method according to claim 5, wherein the polyolefin sheet is formed of polypropylene, and the polyolefin sheet is heated in the range of 160° C. to 180° C. in the uniting step.

### Claim 8 (depends on 5)

The wafer processing method according to claim 5, wherein the polyolefin sheet is formed of polystyrene, and the polyolefin sheet is heated in the range of 220° C. to 240° C. in the uniting step.

### Claim 9 (depends on 1)

The wafer processing method according to claim 1, wherein the wafer is formed of a material selected from the group consisting of silicon, gallium nitride, gallium arsenide, and glass.