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:
Dec. 29, 1998
Filed:
Aug. 11, 1997
Rajwant Singh, Brea, CA (US);
Gerald A Krulik, San Clemente, CA (US);
Applied Chemical Technologies, Inc., Santa Ana, CA (US);
Abstract
This invention relates to a method for increasing the effective process life and chemical efficiency of use of aqueous-based developer solutions used for chemical development of photoresists such as are used in the printed circuit industry. The activity is maintained by regenerating some of byproducts during the process to active carbonate, by controlled additions of alkaline hydroxide instead if conventional carbonate solution. The pH and thus the development speed can automatically be controlled at any desired constant value. This invention allows simple automation of printed circuit photoresist development, with reduced chemical costs and increased chemical usage efficiency and thus reducing the industrial waste volume.