NEAR-SURFACE MODIFICATION OF SILICA STRUCTURE INDUCED BY CHEMICAL-MECHANICAL POLISHING

Planarization of dielectric materials in multilevel devices has become an important topic in recent years. Planarization achieved through ch emical/mechanical polishing (CMP) is the foremost of the techniques av ailable to provide an appropriate low-topography surface for accurate lithography. In this study the effects of the planarization process on deposited SiO2 films, a material to which CMP is frequently applied, have been examined. The analysis, completed using transmission electro n microscopy and Fourier-transform infrared spectroscopy, revealed evi dence of chemical/structural modification of the SiO2 to 100-200 nm fr om the polished surface and more heavily altered or deformed regions e xtending to a few tens of nm in depth.