Hydrogensilsesquioxane (HSQ) (low-k) films were prepared by spin-on deposition using D4 (octamethyl cyclotetrasiloxane) as a sacrificial porous material. The dielectric constant of silica films significantly changed from 3.0 to 2.2. Fourier transform infrared spectroscopy was used to identify the network structure and cage structure of the Si-O-Si bond and other bonds that may appear. We studied the structural and electrical properties of the spin-coated films prepared by mixing HSQ and D4 films after oxygen plasma exposure for 5 min, and studied the structural recovery of the damage by annealing at 350 degrees C for 1.5 h in a nitrogen (N-2) ambient. This structure results in significant lowering of the dielectric constant (k) on annealing at 350 degrees C for 1.5 h in an N-2 ambient and improvement in the leakage current density.