Photosensitive Polyimides

Abstract

AbstractPhotosensitive polyimides are used as insulation and protection layers for microelectronics. They can easily give fine-patterned films with excellent characteristics of polyimides by photolithographic procedure.Photosensitive groups such as double bonds, azides, o-nitrobenzyl and o-naphthoquinonediazides. These photosensitive groups are incorporated to polymer chains through covalent bonds or acid-base ion bonds. Some polyimides have photosensitivity even without intentionally introduced photosensitive groups. Most of photosensitive polyimides are negative working, and a few of them are positive working.Characteristics of photosensitive polyimides are determined by two factors, the way of introducing photosensitive groups and the structures of polyimide backbone chains. Photosensitivity, resolution, purity and easiness of imidization mainly depends on the former factor. The film properties after curing are mainly determined by the latter. The film properties, however, are affected by the former when imide cyclization is imperfect.Photosensitive polyimides are widely used as protection and insulation layers of VLSI, multi-chip modules for computers, telecommunication, linephotosensors, thermal-heads, etc.