Patent ID: 6117279
Filing Date: 2000-09-12
Classification: C23C,H01J

Abstract:
An ionized physical vapor deposition apparatus comprising:a sealable vacuum chamber having a volume therein for containing a processing gas at a vacuum pressure level;a sputtering cathode in the chamber at an end of the volume, the cathode including a target support for holding a sputtering target thereon facing the volume of the chamber;a cathode power source connected to the sputtering cathode for energizing the cathode;a substrate support in the chamber at an end of the volume opposite the target support for supporting thereon, facing the target across the volume, a substrate to be coated with material sputtered from a target supported on the target support;an RF energy source having an RF frequency and coupled into the volume to energize a secondary RF plasma in the gas therein of sufficient density to ionize sputtered material moving from the target through the volume, the RF energy source including at least one coil surrounding the volume of the chamber between the substrate support and the target support to inductively couple RF energy into the volume to energize the secondary plasma;electrically conductive shield structure extending around the chamber between the coil and the volume having a potential thereon that electrically floats at the RF frequency of the RF energy source with the potential of the plasma, the shield structure being configured and positioned to intercept sputtered material moving radially outwardly from the volume, the shield structure having at least one axial discontinuity therein sufficient to interrupt conductive paths in the shield structure from extending circumferentially around the chamber so that the coil passes RF energy therethrough from the coil into the volume; anda filter, connected between the shield and a voltage control circuit, having a high impedance at the frequency of the RF source and having a low DC impedance such that, when energy from the cathode power source produces a main plasma in the gas in the chamber which sputters material from a target on the target support and into the volume, and a secondary plasma is formed in the volume by energy inductively coupled from the RF energy source, negative charge arriving on the shield structure is conducted to the voltage control circuit while the shield structure electrically floats at the RF frequency with the plasma so that the plasma sheath between the plasma and the shield structure is narrow and the plasma sufficiently fills the volume to effectively ionize the sputtered material moving from the target through the volume so that it is steerable toward and normal to a substrate on the substrate support.