# US 10,483,144 B2 · Method for determining front and back of single-crystal wafer

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- Number: US 10,483,144 B2
- Document ID: US10483144B2
- Status: Granted
- Kind: B2
- Application number: 15/754,410
- Filed: 2016-08-18
- Published: 2018-08-30
- Granted: 2019-11-19
- Earliest claimed: 2015-09-03
- Assignees: Shin-Etsu Handotai Co., Ltd.
- Applicants: Shin-Etsu Handotai Co., Ltd.
- Inventors: Shiroyasu Watanabe
- Web page: https://patentgrep.com/patent/US10483144B2

## CPC

- H10P 72/50: for positioning, orientation or alignment
- G01N 23/20008: Constructional details of analysers, e.g. characterised by X-ray source, detector or optical system; Accessories therefor; Preparing specimens therefor (monochromators for X- rays using crystals G21K1/06)
- G01N 23/207: Diffractometry using detectors, e.g. using a probe in a central position and one or more displaceable detectors in circumferential positions
- G01N 2223/6116: semiconductor wafer
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

A method for determining front and back of a single-crystal wafer including: using, as the single-crystal wafer, one having a crystal plane which is laterally asymmetrical to a reference direction connecting a center of a cut for orientation identification formed in an end face of the single-crystal wafer with a center of the single-crystal wafer; noticing the laterally asymmetrical crystal plane, applying an X-ray to the single-crystal wafer, and detecting a diffracted X-ray to measure an angle formed between an orientation of the noticed crystal plane and the reference direction; and determining whether a surface of the single-crystal wafer is a front surface or a back surface from a value of the measured angle. Consequently, the method for determining a front and a back of a single-crystal wafer which can assuredly determine the front and the back of the single-crystal wafer and is superior in cost can be provided.

## Claims

### Claim 1

A method for determining a front and a back of a single-crystal wafer comprising:
using, as the single-crystal wafer, one having a crystal plane which is laterally asymmetrical to a reference direction connecting a center of a cut for orientation identification formed in an end face of the single-crystal wafer with a center of the single-crystal wafer;
noticing the laterally asymmetrical crystal plane, applying an X-ray to the single-crystal wafer, and detecting a diffracted X-ray to measure an angle formed between an orientation of the noticed crystal plane and the reference direction; and
determining whether a surface of the single-crystal wafer is a front surface or a back surface from a value of the measured angle.

### Claim 2 (depends on 1)

The method for determining a front and a back of a single-crystal wafer according to claim 1, wherein an orientation deviation of the cut from a predetermined orientation is measured by obtaining a difference between an actual measured value and a theoretical value of the angle formed between the orientation of the noticed crystal plane and the reference direction as well as performing the determination of a front and a back.

### Claim 3 (depends on 2)

The method for determining a front and a back of a single-crystal wafer according to claim 2, wherein, as the single-crystal wafer which is subjected to the determination of a front and a back, a wafer whose wafer main surface has a crystal plane {1 1 0} is used.

### Claim 4 (depends on 3)

The method for determining a front and a back of a single-crystal wafer according to claim 3, wherein, when the wafer whose wafer main surface has the crystal plane {1 1 0} is used as the single-crystal wafer which is subjected to the determination of a front and a back, the orientation of the noticed crystal plane is an orientation of a (1 −1 0) plane.

### Claim 5 (depends on 4)

The method for determining a front and a back of a single-crystal wafer according to claim 4, wherein the cut for orientation identification is a notch or an orientation flat.

### Claim 6 (depends on 3)

The method for determining a front and a back of a single-crystal wafer according to claim 3, wherein the cut for orientation identification is a notch or an orientation flat.

### Claim 7 (depends on 1)

The method for determining a front and a back of a single-crystal wafer according to claim 1, wherein, as the single-crystal wafer which is subjected to the determination of a front and a back, a wafer whose wafer main surface has a crystal plane {1 1 0} is used.

### Claim 8 (depends on 7)

The method for determining a front and a back of a single-crystal wafer according to claim 7, wherein, when the wafer whose wafer main surface has the crystal plane {1 1 0} is used as the single-crystal wafer which is subjected to the determination of a front and a back, the orientation of the noticed crystal plane is an orientation of a (1 −1 0) plane.

### Claim 9 (depends on 8)

The method for determining a front and a back of a single-crystal wafer according to claim 8, wherein the cut for orientation identification is a notch or an orientation flat.

### Claim 10 (depends on 7)

The method for determining a front and a back of a single-crystal wafer according to claim 7, wherein the cut for orientation identification is a notch or an orientation flat.

### Claim 11 (depends on 1)

The method for determining a front and a back of a single-crystal wafer according to claim 1, wherein the cut for orientation identification is a notch or an orientation flat.

### Claim 12 (depends on 2)

The method for determining a front and a back of a single-crystal wafer according to claim 2, wherein the cut for orientation identification is a notch or an orientation flat.