The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 26, 2004
Filed:
Jan. 09, 2003
Norihiro Kobayashi, Annaka, JP;
Shoji Akiyama, Annaka, JP;
Yuuichi Matsumoto, Annaka, JP;
Masaro Tamatsuka, Annaka, JP;
Shin-Etsu Handotai Co., Ltd., Tokyo, JP;
Abstract
According to the present invention, there are provided a method for heat treatment of silicon wafers wherein a silicon wafer is subjected to a heat treatment at a temperature of from 1000° C. to the melting point of silicon in an inert gas atmosphere, and temperature decreasing in the heat treatment is performed in an atmosphere containing 1-60% by volume of hydrogen, a method for heat treatment of silicon wafers under a reducing atmosphere containing hydrogen by using a rapid heating and rapid cooling apparatus, wherein temperature decreasing rate from the maximum temperature in the heat treatment to 700° C. is controlled to be 20° C./sec or less, and a silicon wafer which has a crystal defect density of 1.0×10 defects/cm or more in a wafer bulk portion, a crystal defect density of 1.0×10 defects/cm or less in a wafer surface layer of a depth of 0.5 &mgr;m from the surface, a crystal defect density of 0.15 defects/cm or less on a wafer surface and surface roughness of 1.0 nm or less in terms of the P-V value. By these, crystal defects in wafer surface layers can be reduced by a simple method with a small amount of hydrogen used without degrading microroughness of wafers.