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:
Jun. 28, 1988
Filed:
Sep. 09, 1985
Frederick Plumb, Horsham, GB;
Christopher Wright, Findon, GB;
Nicholas J Bright, Cowfold, GB;
Derek Aitken, Dorking, GB;
Bernard Harrison, Crawley, GB;
Applied Materials, Inc., Santa Clara, CA (US);
Abstract
A method for operating an ion source having a filament-cathode and an anode. The method includes supplying direct current electrical power between the anode and the filament-cathode characterized by substantially constant arc current there between and varying arc voltage on the filament-cathode. Direct current electrical power is also supplied across the filament-cathode. The value of the arc voltage is monitored and the magnitude of electrical power supplied to the filament-cathode is altered in response to detected changes in the arc voltage to return the arc voltage to substantially a preset reference value. The monitoring step and the altering step are carried out at regular preset intervals. The altering step includes deriving an filament power error signal as a prearranged function which includes the difference in values between the monitored arc voltage and the preset reference value multiplied by a predefined integral gain value. The altering step also includes altering the magnitude of electrical power supplied to the filament-cathode by the value of the filament power error signal.