Title:
IMPURITY REMOVING METHOD FOR INSIDE OF SILICON WAFER
Document Type and Number:
Japanese Patent JP3558759
Kind Code:
B
Abstract:
PROBLEM TO BE SOLVED: To obtain a silicon wafer having an excellent electric characteristic by removing the impurities in a wafer easily and accurately.
SOLUTION: On the surface of a silicon wafer 1 a strain layer 4 is formed by sand blasting by the use of SiO2 powder, and this strain layer 4 formed part is oxidized thermally in a dry oxygen gas atmosphere to change it into a thermal oxide film 5. After this thermal oxide film 5 and a silicon surface layer 6a just under it are dissolved and removed over to a total thickness of 1μm with a mixed solution of hydrofluoric acid, nitric acid, and acetic acid, they are washed by water. When the whole of the wafer after the removal processing is dissolved separately with a chemical and this dissolved solution is analyzed, no metal impurities are detected.
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Inventors:
Ota, Yutaka
Saijo, Hirofumi
Kosugi, Akira
Saijo, Hirofumi
Kosugi, Akira
Application Number:
JP1995000292045
Publication Date:
May 28, 2004
Filing Date:
October 14, 1995
Export Citation:
Assignee:
SHIN ETSU HANDOTAI CO LTD
NAOETSU DENSHI KOGYO KK
NAOETSU DENSHI KOGYO KK
International Classes:
H01L21/322; H01L21/02; (IPC1-7): H01L21/322