Vapor deposition polymerization of polyimide for microelectronic applications

Abstract

We report the high-throughput vapor deposition polymerization (VDP) of smooth, uniform polyimide films for microelectronic applications. Using infrared (IR) spectroscopy, waveguiding refractive index measurements, atomic force microscopy, and matrix assisted laser desorption ionization, we have characterized both cured and uncured films. Uncured VDP films consist of oligomers (up to tetramers) and unreacted monomeric species. Cured VDP films are chemically identical to commercially available spin cast polyimides. Both IR and refractive index anisotropy are used to determine the extent of cure, and the stoichiometry of the cured film. Integration of the VDP films into a multichip module process is presented, and the application of VDP films in ultra-large-scale integrated circuit manufacturing is discussed. Finally, the vapor deposition of 3,3′,4,4′-biphenyltetracarboxylic dianhydride and p-phenylenediamine, a high performance polyimide system, is presented.