Patent ID: 7300889

Claim:
A method for forming a coating film, comprising the steps of: applying a raw material of a low dielectric constant onto a surface of a plate-like material to be treated; reducing oxygen concentration in the atmosphere surrounding the plate-like material to be less than or equal to 1% before a surface temperature of said plate-like material to be treated rises to 200° C.; cooling the plate-like material, wherein said cooling step is performed at the time of reducing the oxygen concentration in the atmosphere; thereafter heating said plate-like material to be treated to a temperature greater than or equal to 400° C.; and then maintaining the oxygen content in the atmosphere to be less than or equal to 1% until the surface temperature of said plate-like material to be treated lowers to 200° C.; said raw material is an organic SOG obtained by hydrolyzing and condensing at least one alkoxysilane compound expressed by the following equation (I) into an organic solvent under an acid catalyst, RnSi(OR 1 ) 4-n (I) where R is an alkyl group or an aryl group having a carbon number of 1-4, R 1 is an alkyl group having a carbon number of 1-4, and n is an integer of 0-2.