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. 31, 1999
Filed:
Aug. 17, 1998
Jeffrey S Glick, Cupertino, CA (US);
Randolph M Fox, Fremont, CA (US);
Advanced Micro Devices, Inc., Sunnyvale, CA (US);
Abstract
A method and system for preventing a source of ultra-purified water from being contaminated with chemicals includes a source of ultra-purified water and a reservoir containing a chemical source. The reservoir has a chemical delivery valve and a chemical outlet pipe coupled to a chemical delivery line for supplying chemicals to a process chamber during a chemical delivery mode of operation. A first controllable inlet valve has its outlet coupled to the chemical delivery line and the source of ultra-purified water for supplying the ultra-purified water from the source of ultra-purified water to the process chamber during a flushing mode of operation. A second controllable inlet valve has an outlet coupled to the inlet of the first controllable inlet valve and an inlet coupled to the source of ultra-purified water. A source of gas under pressure is coupled between the outlet of the second controllable inlet valve and the inlet of said first controllable inlet valve for creating a virtual air gap. As a result, there is prevented the backflow of the chemical source from the reservoir into the source of ultra-purified water causing contamination thereof during the chemical delivery mode of operation.