# US 6,720,640 B2 · Method for reclaiming delaminated wafer and reclaimed delaminated wafer

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- Number: US 6,720,640 B2
- Document ID: US6720640B2
- Status: Granted
- Kind: B2
- Application number: 10/447,103
- Filed: 2003-05-29
- Published: 2003-11-27
- Granted: 2004-04-13
- Earliest claimed: 1999-11-29
- Assignees: Shin-Etsu Handotai Co., Ltd.; S.O.I. Tec Silicon on Insulator Technologies
- Inventors: Susumu Kuwabara; Kiyoshi Mitani; Naoto Tate; Masatake Nakano; Thierry Barge; Christophe Maleville
- Web page: https://patentgrep.com/patent/US6720640B2

## CPC

- H10P 90/16: {by reclaiming or re-processing}
- H10P 74/277: {Circuits for electrically characterising or monitoring manufacturing processes, e.g. circuits in tested chips or circuits in testing wafers}
- H10P 90/1916: {with separation or delamination along an ion implanted layer, e.g. Smart-cut}
- H10W 10/181: {Semiconductor-on-insulator [SOI] isolation regions, e.g. buried oxide regions of SOI wafers}
- Y10S 438/906: Cleaning of wafer as interim step
- Y10S 438/974: Substrate surface preparation
- Y10S 438/977: Thinning or removal of substrate
- 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
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

In a method for reclaiming a delaminated wafer produced as a by-product in the production of bonded wafer by the ion implantation and delamination method, at least ion-implanted layer on a chamfered portion of the delaminated wafer is removed, and then a surface of the wafer is polished. Specifically, at least a chamfered portion of the delaminated wafer is subjected to an etching treatment and/or processing by chamfering, and then a surface of the wafer is polished. Alternatively, the delaminated wafer is subjected to a heat treatment, and then polished. There are provided a method for reclaiming a delaminated wafer, which provides a reclaimed wafer of high quality that does not generate particles even when it is subjected to a heat treatment with good yield, and such a reclaimed wafer.

## Claims

### Claim 1

A method for reclaiming a delaminated wafer produced as a by-product in the production of bonded wafer by the ion implantation and delamination method comprising:
implanting gas ions from a top surface of a wafer, at a peripheral portion of which a chamfered portion is provided, to form a micro bubble layer;
bringing the ion-implanted wafer into close contact with another wafer; and
subjecting the wafers brought into close contact to a heat treatment to delaminate the wafers at the micro-bubble layer as a border, wherein a portion from the top surface to the micro-bubble layer on the chamfered portion of the delaminated wafer, which was not bonded to the other wafer and remains on the delaminated wafer, is removed by subjecting, the delaminated wafer to another heat treatment, and then a surface of the wafer is polished.

### Claim 2 (depends on 1)

A wafer reclaimed by the method according to claim 1.

### Claim 3 (depends on 1)

The method for reclaiming a delaminated wafer according to claim 1, wherein the heat treatment of the delaminated wafer is performed in an oxidizing atmosphere.

### Claim 4 (depends on 1)

The method for reclaiming a delaminated wafer according to claim 1, wherein the heat treatment of the delaminated wafer is performed at a temperature of 500° C. or more for several minutes to several hours.

### Claim 5 (depends on 1)

The method for reclaiming a delaminated wafer according to claim 1, wherein the heat treatment of the delaminated wafer serves also as a heat treatment for donor annihilation.

### Claim 6 (depends on 3)

The method for reclaiming a delaminated wafer according to claim 3, wherein an oxide film formed on the wafer surface by the heat treatment of the delaminated wafer is eliminated before performing the polishing.

### Claim 7 (depends on 6)

The method for reclaiming a delaminated wafer according to claim 6, wherein the oxide film is eliminated with hydrofluoric acid.

### Claim 8 (depends on 3)

A wafer reclaimed by the method according to claim 3.

### Claim 9 (depends on 4)

A wafer reclaimed by the method according to claim 4.

### Claim 10 (depends on 5)

A wafer reclaimed by the method according to claim 5.

### Claim 11 (depends on 6)

A wafer reclaimed by the method according to claim 6.

### Claim 12 (depends on 7)

A wafer reclaimed by the method according to claim 7.