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:
Feb. 21, 1995
Filed:
Jan. 26, 1994
Toshiaki Iwabuchi, Yabutsukahonmachi, JP;
Benkan Corporation, Tokyo, JP;
Abstract
A slow vent valve for semiconductor wafer manufacturing equipment is disclosed, which generates a gentle flow of nitrogen gas to the vacuum chamber enough to maintain an undisturbed ambient environment for the wafer being processed in the chamber, protecting the product from disturbed by particulate raised or objectionable ambient stirring caused by the entering gas. The valve includes an adjustable cam mechanism including a valve open timing adjuster and a slow-venting adjuster. The valve open timing adjuster changes the initial diaphragm pressing force on the valve seat, to thereby determine the open speed and the open timing of the valve to take a lift off the valve seat. The slow venting adjuster is provided to adjust the resistance of a spring that exerts downward pressure on a second piston integrated with the valve rod, to thereby slow the slightly upward movement of the rod to operate the diaphragm to permit a slowed flow of nitrogen gas to the vacuum chamber.