Silicon oxide films deposited by Ar-H-2 sputtering exhibited significantly smaller internal stresses than conventional films deposited by Ar-O-2 sputtering. This phenomenon was found to be caused by the introduction of Si-H bonds into the Si-O-Si network structure. As a result of hydrogenation, the number of planar ring type defects in the network was successfully reduced, and the Si-O bonding force constant seemed to decrease, judging from Raman and IR spectroscopy. These results suggest that the hydrogenation produced a structural relaxation of the Si-O-Si network, leading to the reduction in stress.