Growth, characterization, and kinetic studies of the low-temperature reaction, of vapor deposited polyimide films

An Ultra High Vacuum (UHV) Molecular Beam Deposition (MBD) method for growing polyimide (PI) films has been developed. Such films have been characterized using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), Surface Force Microscopy (SFM), Grazing Incidence X-ray Diffraction (GIXD) using Synchrotron radiation, Optical Microscopy, Ellipsometry, Stress-Strain Measurements, and Laser Interferometry.; PMDA-ODA PI films of quality equal or exceeding spun films can be produced using MBD and subsequent heat treatments determined in this study.; The crystal structure of MBD PMDA-ODA PI films has been determined to be orthorhombic, with unit cell parameters a = 0.648 nm, b = 0.408 nm and c = 3.222 nm.; The top 10 nm closest to PI/air interface consist of polymer material with much higher crystallinity than the bulk of the film. In this layer the intrachain periodicity of the polymer chains is increased close to its maximum, corresponding to the planar zig-zag structure of the chain (second order helix). Because MBD is a solventless method, and higher crystallinity and extended chain configuration in the surface layers is observed in both MBD and spin-coated PI films, it is concluded that the solvent existing in spin-coated PI films before curing, is not responsible for these observations.; The MBD technique was successfully used to grow PI films from ODPA and APB for the first time. Ultrathin to thick films with high thickness uniformity can be produced. As-deposited films are mixtures of monomers and polymer. FTIR results demonstrate that cured MBD films are chemically indistinguishable from spun films. Curing in vacuum results in discontinuous films.; The low temperature ({dollar}le{dollar}20{dollar}spcirc{dollar}C) amidization reaction proceeds with the formation of dimers. Surface diffusion in a void network existing in as-deposited films is considered to be the kinetically controlling mechanism. The measured activation energy for the amidization reaction is 0.53 {dollar}pm{dollar} 0.03 eV.