Method for calculating a height position of silicon melt surface, method for pulling silicon single crystal, and silicon single crystal pulling apparatus

Patent metadata

Field	Value
Publication number	US-9587325-B2
Application number	US-201314375080-A
Country	US
Kind code	B2
Filing date	Jan 22, 2013
Priority date	Feb 21, 2012
Publication date	Mar 7, 2017
Grant date	Mar 7, 2017

Abstract

A method for calculating a height position of a silicon melt surface at the time of pulling a CZ silicon single crystal is disclosed, including: obtaining a first crystal diameter measured from a fusion ring on a boundary of the silicon melt and the silicon single crystal by using a CCD camera installed at an arbitrary angle relative to the silicon single crystal, and a second crystal diameter measured by using two CCD cameras installed parallel to both ends of a crystal diameter of the silicon single crystal; and calculating the height position of the silicon melt surface in the crucible during pulling of the silicon single crystal from a difference between the first crystal diameter and the second crystal diameter. As a result, a method for enabling further accurately calculating a height position of a silicon melt surface at the time of pulling a silicon single crystal is provided.

First claim

The invention claimed is:

1. A method for calculating a height position of a silicon melt surface at the time of pulling a silicon single crystal from a silicon melt contained in a crucible based on the Czochralski method comprising:
obtaining a first crystal diameter measured from a fusion ring on a boundary of the silicon melt and the silicon single crystal by using a CCD camera installed at an arbitrary angle relative to the silicon single crystal, and
a second crystal diameter measured by using two CCD cameras installed parallel to both ends of a crystal diameter of the silicon single crystal; and
calculating the height position of the silicon melt surface in the crucible during pulling of the silicon single crystal from a difference between the first crystal diameter and the second crystal diameter.

2. The method for calculating a height position of a silicon melt surface according to claim 1 ,
wherein the height position of the silicon melt surface is calculated by obtaining a travel distance ΔH from a predetermined height position based on ΔH=ΔD/(2 tan θ) (θ represents the arbitrary installation angle relative to the silicon crystal of the CCD camera used for measuring the first crystal diameter, and ΔD represents a difference between the first crystal diameter and the second crystal diameter).

3. A method for pulling a silicon single crystal,
wherein a height position of a silicon melt surface is calculated by using the method for calculating a height position of a silicon melt surface according to claim 1 , and a silicon single crystal is pulled while controlling the height position of the silicon melt surface based on a result of the calculation.

4. A method for pulling a silicon single crystal,
wherein a height position of a silicon melt surface is calculated by using the method for calculating a height position of a silicon melt surface according to claim 2 , and a silicon single crystal is pulled while controlling the height position of the silicon melt surface based on a result of the calculation.

Assignees

• Shinetsu Handotai Kk

Inventors

• Masuda Naoki
• Yanagimachi Takahiro

Classifications

• G01B21/08

  for measuring thickness · CPC title

• C30B29/06

  Silicon · CPC title

• G01B11/08

  for measuring diameters · CPC title

• C30B15/20

  Controlling or regulating (controlling or regulating in general G05) · CPC title

• G01B11/0608

  Height gauges · CPC title