Method of evaluating the cleanliness of silicon wafers

Abstract

The cleanliness of silicon wafers is evaluated. At various stages of I.C. manufacture, silicon wafers may contain undesirable inorganic and organic contaminants and residues, the presence of which may be due to initial growing and slicing or to subsequent manufacturing steps such as the removal of photoresists. The present method involves differential etching of the silicon wafers. In a manner that removes silicon at a much faster rate than the contaminants and residues are removed. The differential etching is effected by subjecting the wafers to a low pressure, low temperature, RF, reactive plasma which includes a halocarbon gas, and oxygen for a time sufficient to texture the wafer. The differential etching continues at least until the onset of texturing which replicates the pattern of contaminants or residues initially present thereon for visual inspection.