PROPERTIES AND PHOTODEFINITION OF POLY(AROMATIC DIACETYLENES)

Diacetylene copolymers prepared by oxidative coupling of 4,4'-diethyny ldiphenyl ether and m-diethynyl benzene and 4,4'-diethynyldiphenyl eth er and nylphenoxy)-2,2',3,3',5,5',6,6'-octafluorobiphenyl can be photo chemically cross-linked with a dose of 30 and 60 mJ/cm2 mum (lambda = 365 nm), respectively. Patterns in films up to 10 mum thick have been produced with features as small as approximately 12 mum with a contras t of ca. 2. The diethynylbenzene-containing polymer is oxidized slowly at temperatures above 200-degrees-C in air. The fluorinated polymer i s quite stable to oxidation at high temperatures in air and can be str etched 90% before it breaks. Both polymers are quite hydrophobic and a bsorb less than 1% of their weight in water, coefficients of thermal e xpansion are about 50 ppm/degrees-C in the plane of thin films, and ad hesion to Au, Ag, Al2O3, and Si is good. Dielectric constants for the series of poly(aromatic diacetylenes) are found to range from 2.82 for the fluorinated polymer to 3.34 for a copolymer of 4,4'-diethynylbenz ophenone and m-diethynylbenzene.