The crystallite size of the chemical vapor deposited Cu film is usually so large that the Cu film does not fill contact holes or via holes in ultra large scaled integrated circuits well. Therefore it is very important to make the grain size of the Cu film small enough to fill small contact holes with high aspect ratio. Pretreatment of the substrate surface with Ar plasma has been found to be effective in making the grain size of the Cu film smaller and in enhancing the deposition rate of the Cu film. The Cu film deposited on the borophosphosilicate glass (BPSG) has the characteristics of smaller grain size, lower resistivity, and higher degree of (111) preferred orientation, but slightly lower deposition rate than that on the SiO2 glass. The higher resistivity of the Cu film on SiO2 may be due to the formation of the intermetallic compound CU15Si4 at about 400°C which is not formed at the Cu-BPSG interface at the same temperature. Also the dependence of some properties of the Cu film on the substrate material is discussed.