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:
Jan. 26, 1999
Filed:
Aug. 30, 1996
Hitoshi Tsunoda, Nishigou-mura, JP;
Shin-Etsu Handotai Co., Ltd., Tokyo, JP;
Abstract
The invention is predicated in an experimental finding that by setting the temperature in a wafer case, which is made of polypropyrene or like organic resin and in which wafers are stored, to -50.degree. to 15.degree. C., preferably to -50.degree. to 10.degree. C., it is possible to make the increase of organic materials attached during the storage of the wafers substantially to zero. The invention also concerns a method of determining the amount of organic materials attached to wafers, which comprises the steps of allowing a predetermined amount of water drop to be formed on the surface of a wafer, then measuring the angle .alpha. between the wafer and a line drawn from the contact point of 3 phases consisting of the water drop 10, the wafer 1 and gas on the wafer surface to the top of the water drop 10, and thereby obtaining the contact angle .theta. as .theta.=2.alpha., and then determining the amount of organic materials from the contact angle .theta..