Method of forming thick silica-based film

On the substrate, 0.5 ~ 5 [micro] m of the membrane method for easily and efficiently forming a silica-based coating film having a thickness, the coating and the coating liquid supplied to the coating film, and provides a method of manufacturing the same. The present invention is Si (OR)4 A silicon compound represented by (A) and / or ROnenSi (OR2)4-n (Where, n is an integer of 1-3) and the silicon compound (B) represented by, R3CH2Alcohol represented by OH (C) and the oxalic acid (D) to produce a solution of the polysiloxane having a polystyrene-reduced number average molecular weight of 2000-15000 by heating at 50 ~ 180 & lt; 0 & gt; C the reaction mixture in the presence of water in the absence containing a specific ratio and, applying a coating liquid containing the solution to a substrate surface, a method of forming the silica-based coating film comprising a step of heat-curing a coating film obtained by 80 ~ 600 & lt; 0 & gt; C by the coating, the thickness of 0.5 ~ 5 [micro] m film having, and the film coating solution and the method of manufacturing the same is supplied to the.