Patent ID: 6849470

Claim:
A method of manufacturing a semiconductor device, said method comprising: a first step of forming a substrate having a semiconductor region; a second step of evaluating an optical property of said semiconductor region; a third step of performing an etching process with respect to said semiconductor region; and a fourth step of controlling a condition for said etching process based on an optical property of said semiconductor region evaluated in said second step; wherein said second step includes the steps of: supplying measurement light to said semiconductor region; intermittently supplying exciting light to said semiconductor region; and calculating a change rate of a reflectance of the measurement light by dividing a difference between the respective reflectances of the measurement light in the presence and absence of said exciting light supplied to said semiconductor region by the reflectance of the measurement light in the absence of the exciting light; said method further comprising, prior to said second step, the steps of: introducing an impurity at a high concentration into said semiconductor region of said substrate and depositing an interlayer insulating film on said semiconductor region; and selectively removing said interlayer insulating film by plasma etching to form an opening reaching said semiconductor region, wherein said third step includes performing light dry etching with respect to the semiconductor region exposed at a bottom surface of said opening to remove a damaged layer caused by said plasma etching and predetermining a proper range of the change rate of the reflectance of said measurement light when an electric property of the semiconductor region is proper and said fourth step includes performing said light dry etching such that said change rate of the reflectance falls within said proper range.