Classification of etch pits at silicon wafer surface using image-processing instrument

An image-processing instrument with an algorithm for the classification of etch pits such as flow pattern defects (FPDs), small pits (SPs) and large p its (LPs) revealed on silicon wafer surfaces after preferential etching was developed. In comparison with the usual human inspection, this instrument has the merit to obtain two-dimensional distributions of these pits in the wafer. Using this instrument, the pit distribution in two wafers taken from Czochralski (CZ) silicon grown at different growth rate was obtained. It w as found that (i) the distributions of FPDs, SPs and LPs differed in each w afer, and (ii) the etch pit density changed with the growth rate of CZ sili con. (C) 2000 Elsevier Science B.V. All rights reserved.