Method of manufacturing semiconductor integrated circuit device having insulating film formed from liquid substance containning polymer of silicon, oxygen, and hydrogen

A method of manufacturing a semiconductor integrated circuit device, comprising the steps of:

• (a) forming a silicon nitride film on a principal surface of a semiconductor substrate and subsequently applying a liquid substance containing a polymer of silicon, oxygen and hydrogen as principal ingredient onto said silicon nitride film;
• (b) forming an insulating film by subjecting said liquid substance to a first heat treatment, thereby gasifying the solvent thereof;
• and
• (c) forming a contact hole through said insulating film and said silicon nitride film by etching said insulating film with a high etching rate relative to that of said silicon nitride film, and subsequently etching said silicon nitride film.