AN ADHESION STUDY OF POLY(PHENYLQUINOXALINE) ON SILICON-WAFERS

This study is an investigation of the adhesion between poly (phenylqui noxaline) (PPQ) and gamma-aminopropyltriethoxysilane (gamma-APS)-treat ed silicon wafers. In order to determine the locus of failure of the P PQ film-coated wafers, when the coating was mechanically removed from the surface, the surface-sensitive techniques of X-ray photoelectron s pectroscopy and contact angle measurements were employed. This permitt ed an analysis of the surface that was exposed when the film was remov ed from the substrate. In addition, FTIR spectroscopy was used to stud y the effect of the thermal treatment of the film-coated wafers on the silane layer. Treatment of the coated wafers up to temperatures in ex cess of 250 degrees C caused a deterioration of the gamma-APS layer, l eading to a loss in adhesion of the coating, which was likely a result of the decrease in the density of the PPQ chains, which become anchor ed in the silane layer as the silanol groups condense during curing. W hen treatment temperatures are allowed to reach 400 degrees C, the sil ane layer becomes severely degraded. It was found that the locus of fa ilure remained the same, regardless of whether or not the coated wafer was subjected to aging in boiling water. (C) 1993 John Wiley and Sons , Inc.