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:
Nov. 27, 1984
Filed:
Feb. 15, 1984
Daisuke Makino, Hitachi, JP;
Yasuo Miyadera, Shimodate, JP;
Hitachi Chemical Company, Ltd., Tokyo, JP;
Abstract
An improved method of preparing polyamide acid for processing of semiconductors from a diamine and a tetracarboxylic acid dianhydride with a diaminocarbonamide, is provided (1) by reacting the components at below 40.degree. C. until the reduced viscosity reaches above 0.5 dl/g. at 30.degree. C., and then, (2) by adjusting the reduced viscosity to more than 0.3 dl/g, at 30.degree.0 C. and the solution viscosity to 500-3,000 cps at 25.degree. C. by heating at 50.degree.-100.degree. C. By applying the polyamide acid obtained by the method to semiconductor apparatus, they get sufficient heat-resistance without pin holes, and their reliability may be greatly improved.