2005 Volume 18 Issue 2 Pages 307-312
A low-K and low-CTE polyimide, CBDA/TFMB (CBDA = 1,2,3,4-cyclobutanetetracarboxylic dianhydride, TFMB = 2,2'-bis(trifluoromethyl)benzidine) was applied to photosensitive materials. Poly(amic acid) (PAA) of this system was modified using imide-containing diamines to control the solubility in alkaline solutions. Copolymerization using them made possible to form positive-tone fine pattern in combination with diazonaphthoquinone. Additionally it was found that this PAA film is quite soluble in some environmentally friendly (biodegradable) solvents, e.g., alcohols, glycols, and their monoalkyl ethers. PAA film containing an ionic bonding-type methacrylate and a photoinitiator gave fine negative patterns. The corresponding PI films cured from these photosensitive PAA films exhibited a low CTE, a low K, a high Tg, and high transparency comparable to the original PI film.
