Polyimide films, resistivity data

This universal film thickness equation immediately unifies all prior apparently conflicting film thickness data correlations. For example, one of the recurring sources of controversy and confusion in the literature is the observed variability of the exponent p in empirical and semi-empirical correlations of the form h 1/to. Some have generally assumed that p = 1/2 while others argue that p 2/3 (11,17). On the contrary, the observed values of the exponent p is in the range of 0.40-0.82 for various photoresists, electron beam resists, polyimide coatings, etc. 

Auger electron spectroscopy with depth profiling via argon ion etching (position and thickness of near-surface layer), transmission electron microscopy of ultramicrotomed cross-sections (physical internal structure), elemental analysis (extent of metal salt conversion), and surface electrical resistivity versus temperature profiles (continuity of near-surface layer). The data from these techniques were used cooperatively to develop a model for these microcomposite polyimide films. The model represents the sample as three distinct regions. Fig. 1. The bulk of the film contains either converted (e.g. Ag) or nonconverted (e.g. C0CI2) additive in a predominately polyimide environment. An oxide-rich (e.g. 0 ) or metal-rich layer (e.g. Ag, Au) interspersed with polyimide accounts for the second region. 

The data indicate that the properties of the lower glass transition temperature metal ion modified polyimides are altered more than the properties of the higher glass transition temperature metal ion modified polyimides. Extraction removes both cobalt and chlorine from the films and slightly increases bulk thermal stability and both surface resistivity and bulk electrical resistivity. Details pertaining to the structure, analysis and properties of these novel gradient composites are discussed. 

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