Photosensitive polybenzoxazole based on a poly(o-hydroxy amide), a dissolution inhibitor, and a photoacid generator

摘要

A positive-type photosensitive polybenzoxazole (PSPBO), based on a poly (o-hydroxy amide) (PHA), the dissolution inhibitor (DI) 9,9-bis(4-tert-butoxycarbonyloxyphenyl)fluorene (t-Boc BHF), and the photoacid generator (5-propylsulfonyloxyimino-5H-thiophene-2-ylidene)-(2-methylphenyl)acetonitrile (PTMA), was developed. Several new tert-butoxycarbonylated compounds as DIs for PSPBOs were prepared from phenolic compounds having a cardolike structure with di-tert-butyl dicarbonate in the presence of 4-dimethylaminopyridine. Among them, t-Boc BHF and 5,5',6,6'-tetra(tert-butoxycarbonyl)-3,3,3',3'-tetramethyl-1,1'-spirobiindane acted as excellent DIs, giving a large dissolution contrast between the exposed and unexposed areas in a 2.38 wt % tetramethylammonium hydroxide solution (TNLAHaq)/5 wt % iso-propanol (i-PrOH). The dissolution behavior of this PSPBO system was studied in relation to the PTMA and t-Boc BHF loadings and postexposure baking temperature. A PSPBO consisting of PHA (77 wt %), t-Boc BHF (20 wt %), and PTMA (3 wt %) exhibited a sensitivity of 34 mJ/cm(2) and a contrast of 5.8 when exposed to 365-nm light (i-line) and developed with an aqueous alkaline developer, 2.38 wt % TMAHaq/5 wt % i-PrOH. A clear, positive image with 6-mu m features and a 10-mu m-thick pattern with high sensitivity and contrast was produced by contact printing and converted into polybenzoxazole patterns upon heating at 350 degrees C for 1 h. (c) 2006 Wiley Periodicals, Inc.