PURPOSE: To obtain a good surface flatness of a base by burying a minute unevenness of the base and increase a reliability, by forming a fluorine resin film and then an inorganic film as surface protecting films on a semiconductor element.

CONSTITUTION: A fluorine-containing polymer is dissolved in perfluorotributyl amine to make a 9wt.% solution. Then, 0.3wt.% of 3-aminopropyl methyl diethoxysilane is added to the solution. Then, this solution is applied by a spin coater onto a 6-inch silicon wafer on which semiconductor devices are fabricated. The wafer is dried for one hour at 50°C and for another one hour at 200°C to form the coating of 3μm in thickness. After that, using a mixed gas of monosilane and ammonia, a silicon nitrode film is formed in the thickness of 1μm by a plasma chemical vapor-phase growth method at the substrate temperature 300°C. Nextly, a photolithography process and a plasma etching process with CF, CHF and Ar are conducted to punch the silicon nitride film and the fluorine resin film for wire bonding and after these processes, a semiconductor device is completed.