Patent ID: 8686101

Claim:
A coating liquid for forming a low dielectric constant amorphous silica-based coating film which has smoothness of its surface, a high film strength and an excellent hydrophobicity, the coating liquid comprising: a silicon compound obtained by hydrolyzing bis(trialkoxysilyl)alkane (BTASA) and alkoxysilane (AS) the presence of tetraalkylammoniumhydroxide (TAAOH) at a temperature in the range from 40 to 80Â° C., the molar ratio of BTASA:AS being in the range 49-9:21 in terms of SiO 2 and the molar ratio of TAAOH:(BTASA+AS) being in the range 1-6:10 in terms of SiO 2 , wherein the weight ratio of TAAOH to the coating liquid is from 4.1 to 12.2 weight percent, wherein the bis(trialkoxysilyl)alkane (BTASA) is bis(trimethoxysilyl)methane (BTMSM), bis(triethoxysilyl)methene (BTESM), bis(trimethoxysilyl)ethane (BTMSE), bis(triethoxysilyl)ethane (BTESE), or a mixture thereof; wherein the alkoxysilane (AS) is methyltrimethoxysilane (MTMS), methyltriethoxysilane (MTES), or a mixture thereof; and wherein the tetraalkylammoniumhydroxide (TAAOH) is tetrapropylammoniumhydroxide (TPAOH), tetrabutylammoniumhydroxide (TBAOH), or a mixture thereof.