It is not easy to evaluate thin film/substrate adherence and characterize the thin film/substrate interface when adherence is strong. For this purpose, a new method (scratch-ESCA test), which is a combination of the scratch test, the peeling (by an adhesive tape) test, and the ESCA (Electron Spectroscopy for Chemical Analysis) measurement, has been developed and applied to the study of CVD (Chemically vapor deposited) WSix (tungsten silicide)/poly (polycrystalline) Si adherence. Besides the conventional adherence evaluation by the scratch test, it is found possible to evaluate the adherence by the ESCA measurement of the amount of WSix films peeled off from poly Si with an adhesive tape after the scratch test and also to carry out the characterization of the Wsix/poly Si interface.The results of the adherence evaluation described above are found to be related with the tendency of WSix films to delaminate or peel off during the semiconductor device manufacturing processes. The interface characterization by ESCA shows that the WSix adherence is affected by the presence of such elements as F, O, C and N at this interface.