THIN POLYIMIDE LAYERS - PREPARATION AND PROPERTIES

Two types of vacuum deposited polyimide layers differing in their mode of preparation-deposition of the monomer vapours on rotary and linear ly moving substrates-have been investigated. The monomers were PMDA an d ODA evaporated from two Knudsen sources on to soda lime glass substr ates. The deposits were transformed to polyimide by heating in air. It was established that there was a strong influence of the dynamic stat e of the substrate during layers formation on the cross-section of the samples. The growth of deposits on rotary substrates were characteriz ed by a higher microhardness and an increased (25%) stability during r eactive ion etching in an oxygen atmosphere. It was experimentally sho wn that the microhardness depended on the conditions of thermal treati ng for imidization of the deposited layers. The properties of the two types of layers are discussed on the basis of the principle difference s in condensation of the monomers. (C) 1998 Elsevier Science Ltd All r ights reserved.