Abstract In this work, chemical vapor deposited low- k films using tetra methyl tetra cyclo siloxanes (TMCTS) precursors were studied. Process parameters studied included low-frequency RF (LFRF) power, high-frequency RF (HFRF) power, pressure, CO 2 flow rates, and precursors flow rate. Results indicated that the reduction of LFRF power, CO 2 flow rate, and increase in HFRF power, pressure, TMCTS flow rate reduces the dielectric constant ( k ). In the TMCTS flow rate, there are two reaction's mechanisms which are mass transport-limited and reaction-limited that govern the reaction at low flow rate and high flow rate of TMCTS, respectively. Oxygen in the process plasma played a major role in breaking the Si–CH 3 and Si–H bonds and forming a silica-like structure having higher k . It was found that the k as inversely proportional to the Si–CH 3 /Si–O ratio and having a linear relationship with hardness and modulus. The low- k films demonstrate good stability and good adhesion property.