A layer of reduced stress is formed on a substrate using an HDP-CVD system by delaying or interrupting the application of capacitively coupled RF energy. The layer is formed by introducing a process gas into the HDP system chamber and forming a plasma from the process gas by the application of RF power to an inductive coil. After a selected period, a second layer of the film is deposited by maintaining the inductively-coupled plasma and biasing the plasma toward the substrate to enhance the sputtering effect of the plasma. In a preferred embodiment, the deposited film is a silicon oxide film, and biasing is performed by application of capacitively coupled RF power from RF generators to a ceiling plate electrode and wafer support electrode.