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:
Mar. 14, 1989
Filed:
Nov. 09, 1987
Fumio Oi, Ashiya, JP;
Haruyoshi Osaki, Toyonaka, JP;
Akihiro Furuta, Takatsuki, JP;
Yukikazu Uemura, Amagasaki, JP;
Takao Ninomiya, Ibaraki, JP;
Yasunori Uetani, Minoo, JP;
Makoto Hanabata, Hyogo, JP;
Sumitomo Chemical Company, Limited, Osaka, JP;
Abstract
A novolak resin for a positive photoresist is provided herein, which resin is produced by the addition condensation reaction of a phenol with formaldehyde. This novolak resin has improved heat resistant and sensitivity properties and the thickness retention of the novolak resins are very high. The novolak resins are characterized in that the area ratio of the gel permeation chromatographic pattern (GPC) as measured by the use of a UV(254 nm) detector, is as follows: a range wherein the molecular weight, calculated as polystyrene, is from 150 to less than 500, not including a phenol and the unreacted monomer, is from 8 to 35%, hereinafter referred to as an A region, the range wherein the molecular weight calculated as polystyrene is from 500 to less than 5000 is from 0 to 30%, hereinafter referred to as a B region, and the range wherein the molecular weight calculated as polystyrene exceeds 5000 is from 35 to 92%, hereinafter referred to as the C region, and wherein the ratio of the B region to the A region is 2.50 or less.