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:
Nov. 28, 1995
Filed:
Sep. 15, 1994
Yukinobu Hikosaka, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
A method for measuring electron density n.sub.p of a plasma in a plasma reaction chamber for semiconductor fabrication processes is capable of an accurate measurement without time-drifting of measuring values and metal contamination to semiconductor wafers. The method comprises injecting electrons in the plasma to generate a plasma oscillation, getting a plasma oscillation frequency .omega..sub.p by antenna and frequency analyzer, and easily computing n.sub.p by a well-known formula using the value of .omega..sub.p. A plasma generating apparatus for semiconductor fabrication processes is capable of keeping the electron density in a plasma reaction chamber constant. The apparatus comprises feed-back circuits for feeding back a deviation signal of the computed (n.sub.p) from a presetting value to an RF oscillator or a gas control unit so as to control RF power or pressure of a source gas, respectively.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile