Patent ID: 7132205

Claim:
A photosensitive resin comprising: an end- capped polybenzoxazole precursor polymer bearing acid labile functional groups having the structure I: wherein k 1 is any number between 0.1 and 2, k 2 is any number between 0–1.9 provided that (k 1 +k 2 )=2; x is an integer from about 10 to about 1000, y is an integer from 0 to about 900 and (x+y)<1000; Ar 1 is selected from the group consisting of a tetravalent aromatic, a heterocyclic group, and mixture thereof; Ar 2 is selected from the group consisting of a divalent aromatic, heterocyclic, alicyclic and aliphatic group; Ar 3 is selected from the group consisting of a divalent aromatic, aliphatic and heterocyclic group; Ar 4 is selected from the group consisting of Ar 1 (OD) k 1 (OH) k 2 and Ar 2 ; D is selected from the group consisting of an acid sensitive group R 1 and a moiety (B—O—R 2 ) containing an acid sensitive group R 2 ; B is a divalent group which is not acid labile, R is an organic group having a carbonyl, carbonyloxy or sulfonyl group attached directly to the terminal NH of the polymer, and the —OR 1 group is not a carbonate group.