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:
May. 25, 2004
Filed:
May. 22, 2002
Joseph T. Verdeyen, Savoy, IL (US);
Wayne L. Johnson, Phoenix, AZ (US);
Murray D. Sirkis, Tempe, AZ (US);
Tokyo Electron Limited, Tokyo, JP;
Abstract
A system for measuring plasma electon densities (e.g., in the range of 10 to 10 cm ) and for controlling a plasma generator ( ). Measurement of the plasma density is essential if plasma-assisted processes, such depositions or etches, are to be adequately controlled using a feedback control. Both the plasma measurement method and system generate a control voltage that in turn controls the plasma generator ( ) to maintain the plasma electron density at a pre-selected value. The system utilizes a frequency stabilization system to lock the frequency of a local oscillator ( ) to the resonant frequency of an open microwave resonator ( ) when the resonant frequency changes due to the introduction of a plasma within the open resonator. The amplified output voltage of a second microwave discriminator may be used to control a plasma generator ( ).