Patent ID: 8227028

Claim:
A method of forming on a substrate an amorphous silica-based coating film with a low dielectric constant of 3.0 or below and a high film strength, as expressed by Young's modulus, of 3.0 GPa or more, which comprises the steps of: (1) coating on the substrate a liquid composition comprising hydrolysate of an organic silicon compound or compounds hydrolyzed in the presence of tetraalkylammonium hydroxide (TAAOH) (i.e., coating step); (2) setting the substrate in a chamber, and then drying a coating film formed on the substrate at a temperature in the range from 25 to 340° C. (i.e., drying step); (3) heating the coating film at a temperature in the range from 105 to 450° C. with introduction of a superheated steam having such a temperature into the chamber (i.e., heating step); and (4) curing the coating film at a temperature in the range from 350 to 450° C. with introduction of a nitrogen gas into the chamber (i.e., curing step).