WAVEFORM FOR IMPROVED ENERGY CONTROL OF SPUTTERED SPECIES

摘要

This disclosure describes systems and methods for regulating the density and kinetic energy of ions in a sputtering deposition chamber. A pulsed DC waveform with a modulated RF signal is generated and applied to the sputtering chamber. Upon termination of a cycle of the pulsed DC waveform, a reverse voltage spike is generated. This reverse voltage spike reverses the polarity of the cathode and anode of the sputtering chamber for some period of time. A reverse voltage limiting circuit is provided so as to limit the reverse voltage spike to a selected reverse voltage threshold. A controller may be employed to control the timing and duration of the application of the DC waveform, the timing and duration of the RF waveform, and the engagement of the reverse limiting circuit.