A chemical vapor deposition process for preparing a low dielectric constant organosilicate (OSG) having enhanced mechanical properties by adjusting the amount of organic groups, such as methyl groups, within the mixture is disclosed herein. In one embodiment of the present invention, the OSG film is deposited from a mixture comprising a first silicon-containing precursor that comprises from 3 to 4 Si—O bonds per Si atom, from 0 to 1 of bonds selected from the group consisting of Si—H, Si—Br, and Si—Cl bonds per Si atom and no Si—C bonds and a second silicon-containing precursor that comprises at least one Si—C bond per Si atom. In another embodiment of the present invention, the OSG film is deposited from a mixture comprising an asymmetric silicon-containing precursor. In either embodiment, the mixture may further contain a porogen precursor to provide a porous OSG film.