Polysilazane-based coating solution for interlayer insulation

A method for the formation of a silicon dioxide-based interlayer insulating coating film on the surface of a substrate which comprises the steps of:

• (A) coating the surface of the substrate with a polysilazane-based coating solution comprising, as a uniform solution:
• (a) an inert organic solvent having a boiling point in the range from 50.degree. to 200.degree. C.;
• and
• (b) a polysilazane modified by the reaction with a trimethylsilylating agent to such an extent that, in a .sup.1 H-NMR spectrometric diagram of the modified polysilazane, the ratio of the area of the peak assignable to SiH.sub.3 to the total area of the peaks assignable to SiH.sub.1 and SiH.sub.2 is in the range from 0.15 to 0.45,
• to form a modified polysilazane-based coating layer;
• (B) subjecting the coating layer to a drying treatment;
• and
• (C) subjecting the dried coating layer to a baking treatment at a temperature in the range from 300.degree. to 800.degree. C. for at least 15 minutes in a moisturized atmosphere to convert the modified polysilazane into silicon dioxide.

A method for the formation of a silicon dioxide-based interlayer insulating coating film on the surface of a substrate which comprises the steps of:

• (A) coating the surface of the substrate with a polysilazane-based coating solution comprising, as a uniform solution:
• (a) an inert organic solvent having a boiling point in the range from 50.degree. to 200.degree. C.;
• (b) a polysilazane modified by the reaction with a trimethylsilylating agent to such an extent that, in a .sup.1 H-NMR spectrometric diagram of the modified polysilazane, the ratio of the area of the peak assignable to SiH.sub.3 to the total area of the peaks assignable to SiH.sub.1 and SiH.sub.2 is in the range from 0.15 to 0.45, and
• (c) a trialkyl amine compound,
• to form a modified polysilazane-based coating layer;
• (A1) keeping the polysilazane-based coating layer at a temperature in the range from 25.degree. to 100.degree. C. for at least 1 minute;
• (B) subjecting the coating layer to a drying treatment at a temperature in the range from 100.degree. to 300.degree. C.;
• and
• (C) subjecting the dried coating layer to a baking treatment for at least 15 minutes at a temperature in the range from 300.degree. to 800.degree. C. in a moisturized atmosphere to convert the modified polysilazane into silicon dioxide.