Process for preparing insulating material having low dielectric constant

A semiconductor device comprising an interlayer insulating film for metal wiring, said film being obtained by a process comprising the steps of:

• a) preparing a mixed complex of matrix resin and pore-forming organic material, said matrix resin is selected from the group consisting of:
• organosilane of the Chemical Formula 1:R1mR2nSiX4−m−n (where each of R1 and R2 which may be the same or different, is a non-hydrolysable group selected from hydrogen, alkyl fluorine-containing alkyl or aryl group;
• X is a hydrolysable group selected from halide, alkoxy or acyloxy;
• and m and n are integers of from 0 to 3 satisfying 0≦m+n≦3) or a partially hydrolyzed condensate thereof,
• organic bridged silane of the Chemical Formula 2:R3pY3−pSi—M—SiR4gZ3−q (where each of R3 and R4 which may be the same or different, is a non-hydrolysable group selected from hydrogen, alkyl, fluorine-containing alkyl, alkenyl or aryl;
• each of Y and Z which may be the same or different, is a hydrolsable group selected from halide, alkoxy or acyloxy;
• M is alkylene or arylene group;
• and p and q are integers of from 0 to 2) or a cyclic oligomer with organic bridge unit (Si—M—Si) or a partially hydrolyzed condensate thereof, and
• a mixture thereof;
• and
• said pore-forming material containing an organic part containing one or more thermally decomposable organic linkage groups, and at least one silyl functional group at the terminal so that the pore-forming material can be connected by covalent bonding with the matrix resin;
• b) coating the mixed complex on a substrate;
• and
• c) heating the mixed complex to remove the organic molecule part of the pore forming material, thereby forming pores inside the complex;
• wherein the film has an average pore diameter less than 20 nm and is substantially free of a phase-separated domain.