A new type of low-k dielectric material, poly(tridecafluoro1,1,2,2, tetrahydrooctyl-co-phenylsilsesquioxane) (PFCPSQ) was synthesized by hydrolysis and condensation reaction of trimethoxysilyl monomers in the presence of a base catalyst in H(2)O/THF mixture solvent at 25 degrees C. Chemical compositions, molecular weight, and structure of the obtained PFCPSQs were characterized using (1)H NMR, (29)Si NMR, FT-IR, and GPC. Dielectric values were examined by a HP-4190 system and a dielectric constant k of 1.92 was obtained.