a method for stripping a film from a wafer substrate includes the steps of inserting a boat holding the wafer into a processing chamber of a cvd apparatus , and injecting gas into the chamber , to thereby strip the wafer of its film . a typical film requiring stripping is a polysilicon film grown on an underlying oxide layer of the substrate . in this case , cif 3 is used to strip the polysilicon film without damaging the oxide layer . accordingly , this method is applicable to the quality testing of semiconductor wafer films using a test wafer . in such quality testing a film is formed on a test wafer substrate at the same time the semiconductor wafer film is formed . the film of the test wafer is tested to evaluate the quality of the formation of the semiconductor wafer film . the test wafer can then be stripped within the chemical vapor deposition apparatus and thus can be reused soon thereafter .