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:
Aug. 05, 1997
Filed:
Feb. 02, 1996
David E Henderson, Fremont, CA (US);
VLSI Technology, Inc., San Jose, CA (US);
Abstract
A vacuum seal for a ball junction between a low pressure chemical vapor deposition (LPCVD) chamber and a vacuum system. In one implementation, the LPCVD chamber is a quartz tube used for deposition of certain chemicals onto and into semiconductor substrates placed therein. The ball junction is formed by the combination of a ball socket coupled at the neck of the LPCVD chamber and a metal ball cover coupled to the vacuum system. In one implementation, the metal ball cover is stainless steel. In lieu of using an elastomer O-ring that can denature under certain temperature ranges, the novel vacuum seal contains a series of annular channels cut into the inside surface of a ball cover. When the ball socket is inserted into the metal ball cover, the channels are bounded by metal on three sides and by the outside surface of the ball socket on the fourth side. Each channel contains a hole coupled to a second vacuum system. The channels are evacuated by the second vacuum system such that the outside surface of the ball socket seals with the inside surface of the metal cover. This vacuum seal is sufficient to contain a rough vacuum (e,g., 760 Torr to 1 m Toro required during LPCVD. Since the O-ring is eliminated, there is no need to temperate regulate the novel ball junction to prevent the O-ring from denaturing and temperatures can be maintained at the ball junction to prevent unwanted sublimation from chamber chemicals (e.g., ammonium chloride).