To provide an application liquid for forming a silica-based coating film for providing an insulating film excellent in mechanical properties and adhesiveness and low in specific inductive capacity, a high-yield method for easily manufacturing a silica-based coating film for providing an insulating film excellent in mechanical properties and adhesiveness and low in specific inductive capacity, and a semiconductor device low in specific inductive capacity and high in reliability.

The application liquid for forming silica-based coating film contains (A) an organic substituent-containing hydrolyzed siloxane polymer (wherein 1-30% of all the organic substituents in the hydrolyzed siloxane polymer must be pyrolyzed in the silica-based coating film manufacturing process), (B) a pyrolytic/volatile organic polymer for pore formation, and (C) an organic solvent capable of dissolving both (A) and (B). The application liquid has a critical surface tension of 29×10-3 N/m or higher and a specific inductive capacity of 2.6 or less as measured at 10 kHz. The application liquid is applied onto a substrate, and allowed to dry at 50-450°C and to set at 200-600°C. The semiconductor device has a silica-based coating film formed by the silica-based coating film manufacturing method.