film from the composition for film formation the composition is applied on a substrate to form a film the substrate which can be coated with the composition may include a semiconductor glass ceramic and metal any coating method which is available in the field for manufacturing a semiconductor device can be used the examples may include spin coating dipping and roller blade the thickness of the formed film may be usually 0 1 to 2 u03bcm for the interlayer insulating film then the formed film is heated in the step called u201c pre bake u201d so that coated film is immobilized due to the evaporation of the solvent in the coating liquid the heating temperature may be high enough to evaporate the solvent in the coating liquid the film thus formed is heated to the temperature high enough to cure harden the polymer and thereby the cured film having pores is obtained it is preferable to heat the film at 200 to 500 u00b0 c consequently the film becomes porous the heating time may be 1 minute to 2 hours more preferably 5 minutes to 1 hour when the heating temperature is too low the film having low mechanical strength may be formed because of insufficient cure when the heating temperature is too high it may not suit the process for manufacturing a semiconductor device accordingly the heating temperature may be more preferably 300 to 450 u00b0 c as for the heating atmosphere air atmosphere and inert gas atmosphere may produce differences in the distribution of film pores and in the mechanical strength then selection of heating atmosphere can control film properties so that any atmosphere may be.