PURPOSE: To obtain titled liquid capable of providing uniform coating film suitable as surface-stabilized film, ply separation film, etc. for semiconductor, by incorporating, as a modifier, a compound of phosphorus, boron, arsenic, or antimony in a polar organic solvent solution of the silicic acid derived from an inorganic silicon compound.

CONSTITUTION: (A) An inorganic silicon compound such as silicic acid is made into an aqueous solution of silicic acid by acidifying with (B) an acid, pref. such as hydrochloric acid, sulfuric acid, phosphoric acid, boric acid. The resulting solution is subjected to dehydration by salting out usng pref. an inorganic electrolyte or/and by the use of a solid dehydrating agent to obtain silicic acid. Subsequently, the polar organic solvent (e.g., methanol) solution of the above silicic acid is incorporated with (C) as a film modifier, a compound of phosphorus, boron, arsenic and/or antimony, thus obtaining the objective coating liquid. The amount of the component (C) is pref. ≤100pts.wt. per 100pts.wt. of the silicon oxide, on an oxide basis.