Innovation via photosensitive polyimide and poly(benzoxazole) precursors - A review by inventor

Abstract

In order to work out indispensable criteria for a promising process of innovation, a historical review is given for two paths of innovation, which the author was involved in as an chemist in electrical industry from the initial idea up to commercialization and application in the field of microelectronics and electronics. The examples concern the approach to thermally stable organic patterns via photosensitive precursors of polyimides (negative mode) and of poly(benzoxazoles) (positive mode). After direct photolithographic patterning the precursor layers can be thermally converted into polyimide and poly(benzoxazole), respectively. The photoresists have been commercialized by licensed chemical companies. They have been and still are mainly applied to memory and logic devices as protective and buffer coatings to reduce the stress caused by an encapsulating resin, and to thin film multichip modules as planarizing interlayer dielectrics.