Abstract: A method of an apparatus for controlling the deposition of a thin film upon a substrate by a radio frequency (RF) sputtering apparatus is disclosed. The apparatus utilizes the predetermined bias voltage vs. vacuum pressure characteristic of the RF sputtering apparatus to control, by a single pressure controller, both the vacuum pressure and the bias voltage. A substrate tuning bias circuit generates an effective DC bias voltage that is determined by the RF impedance of the substrate holder to ground. Through a voltage level shifting circuit, a detected change in the DC bias voltage, e.g., a decrease, causes the pressure controller to adjust, e.g., increase, the vacuum pressure. The change in the vacuum pressure then produces a corresponding adjustment, e.g., an increase, of the bias voltage to stabilize the bias voltage back at a predetermined level.