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:
Oct. 10, 1989
Filed:
Aug. 20, 1987
Fritz Erdmann, Eltville-Martinsthal, DE;
Horst-Dieter Thamm, Eschborn, DE;
Hans-Joachim Staudt, Taunusstein, DE;
Hoechst Aktiengesellschaft, Frankfurt, DE;
Abstract
A process for the preparation of an o-naphthoquinonediazide sulfonic acid ester is disclosed. Esterification of an o-naphthoquinonediazide sulfonic acid halide with a mono- or polyvalent phenolic compound in a solvent is performed in the presence of ammonia, of ammonium salts of weak acids or of aliphatic derivatives of ammonia having 1 to 3 carbon atoms, at a pH within the range from about 1.5 to about 8.5 and a temperature within the range from about 15.degree. C. to about 40.degree. C. The esters of o-naphthoquinonediazide sulfonic acid which are obtained by this process contain only small amounts of metal ions and can be used in photosensitive mixtures satisfying high requirements of the microelectronics industry.