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. 27, 2000
Filed:
May. 19, 1998
Nobumasa Suzuki, Yokohama, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A process for evacuating the inside of a vacuum vessel before a processing gas is introduced into the vacuum vessel. The process includes steps of evacuating the inside of the vacuum vessel through a by-pass evacuation path such that a pressure reduction rate of the pressure inside the vacuum vessel is gradually reduced immediately after the start of evacuation, and opening an evacuation conductance control valve, provided in a principal evacuation path, during or after the evacuation step such that conductance of the evacuation conductance control valve is gradually increased with an elapse of evacuation time. The timing at which the evacuation conductance control valve is started to be opened is controlled so that a pressure reduction rate curve of the pressure inside the vacuum vessel has a minimum value and a maximum value. The minimum value becomes 0.2 times or more a value given immediately after the start of evacuation and the maximum value becomes not greater than the value given immediately after the start of evacuation.