# US 8,771,415 B2 · Method of manufacturing silicon single crystal, silicon single crystal ingot, and silicon wafer

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- Number: US 8,771,415 B2
- Document ID: US8771415B2
- Status: Granted
- Kind: B2
- Application number: 12/604,627
- Filed: 2009-10-23
- Published: 2010-05-06
- Granted: 2014-07-08
- Earliest claimed: 2008-10-27
- Assignees: Sumco Corporation
- Applicants: Shigeru Umeno; Keiichiro Hiraki; Hiroaki Taguchi
- Inventors: Shigeru Umeno; Keiichiro Hiraki; Hiroaki Taguchi
- Web page: https://patentgrep.com/patent/US8771415B2

## CPC

- C30B 29/06: Silicon
- C30B 15/00: Single-crystal growth by pulling from a melt, e.g. Czochralski method (under a protective fluid C30B27/00)
- C30B 15/20: Controlling or regulating (controlling or regulating in general G05)
- C30B 33/12: in gas atmosphere or plasma
- C30B: SINGLE-CRYSTAL GROWTH (by using ultra-high pressure, e.g. for the formation of diamonds, B01J3/06); UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL (zone-refining of metals or alloys C22B); PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (casting of metals, casting of other substances by the same processes or devices B22D; working of plastics B29; modifying the physical structure of metals or alloys C21D, C22F); SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (for producing semiconductor devices or parts thereof H10); APPARATUS THEREFOR

## Abstract

By determining a control direction of a pulling-up velocity without using a position or a width of an OSF region as an index, a subsequent pulling-up velocity profile is fed back and adjusted. A silicon single crystal ingot that does not include a COP and a dislocation cluster is grown by a CZ method, a silicon wafer is sliced from the silicon single crystal ingot, reactive ion etching is performed on the silicon wafer in an as-grown state, and a grown-in defect including silicon oxide is exposed as a protrusion on an etching surface. A growing condition in subsequent growing is fed back and adjusted on the basis of an exposed protrusion generation region. As a result, feedback with respect to a nearest batch can be performed without performing heat treatment to expose a defect.

## Claims

### Claim 1

A method of manufacturing a silicon single crystal, the method comprising:
growing a first silicon single crystal ingot including neither a COP nor a dislocation cluster by a Czochralski method;
slicing a silicon wafer from the first silicon single crystal ingot;
performing reactive ion etching on the silicon wafer in an as-grown state to expose a grown-in defect including silicon oxide as a protrusion on an etching surface, wherein a generation region of the exposed protrusion is a Pv region which includes an oxygen precipitation nucleus in an as-grown state; and
thereafter growing a subsequent silicon single crystal ingot wherein a growing condition of the growing of the subsequent silicon single crystal ingot is adjusted on a basis of a radius of the generation region of the exposed protrusion.

### Claim 2 (depends on 1)

The method as claimed in claim 1, wherein an acceptance or a rejection of the first silicon single crystal ingot is determined on the basis of the generation region of the exposed protrusion.

### Claim 3 (depends on 1)

The method as claimed in claim 1, wherein the growing of the first silicon single crystal ingot creates an ingot which does not include OSF regions.

### Claim 4 (depends on 1)

The method as claimed in claim 1, wherein performing the reactive ion etching includes: etching the silicon wafer using an aqueous solution containing hydrofluoric acid and nitric acid; and performing the reactive ion etching on an etched surface.

### Claim 5 (depends on 1)

The method as claimed in claim 1, wherein performing the reactive ion etching includes: cleaving the silicon wafer; and performing the reactive ion etching on a cleavage surface.

### Claim 6 (depends on 1)

The method as claimed in claim 1, wherein performing the reactive ion etching includes: mirror polishing the silicon wafer; and performing the reactive ion etching on a mirror polished surface.

### Claim 7

A method of manufacturing a silicon single crystal, comprising:
growing a first silicon single crystal ingot including neither a COP nor a dislocation cluster by a Czochralski method;
slicing an evaluation sample from the first silicon single crystal ingot;
performing a reactive ion etching on the evaluation sample in the as-grown state to expose a defect including silicon oxide as a protrusion, wherein a generation region of the exposed protrusion is a Pv region which includes an oxygen precipitation nucleus in an as-grown state; and
adjusting a growing condition of a subsequently-grown silicon single crystal ingot on a basis of a radius of a generation region of the exposed protrusion exposed on the evaluation process,
wherein the subsequently-grown silicon single crystal ingot is thereby pulled up under a condition where the protrusion is not formed on the surface of the evaluation sample.

### Claim 8 (depends on 7)

The method as claimed in claim 7, wherein, in the growing of the first silicon single crystal ingot, when a temperature gradient in a central portion is defined as Gc and a temperature gradient in an outer circumferential portion is defined as Ge, the silicon single crystal ingot is grown under a condition of Gc/Ge≧1.

### Claim 9 (depends on 7)

The method as claimed in claim 7, wherein an OSF does not exist in a region where the protrusion is not generated by performing the reactive ion etching.

### Claim 10 (depends on 7)

The method as claimed in claim 7, wherein an oxygen concentration in the silicon single crystal is 9×1017 atoms/cm3 or less.

### Claim 11 (depends on 7)

The method as claimed in claim 7, wherein the evaluation sample is obtained by slicing the silicon single crystal ingot in a radial direction or in an axial direction.