Ultrasonic enhancement of aluminum step coverage and apparatus

摘要

A method and apparatus for sputter depositing aluminum onto a semiconductor substrate to fill micron and submicron vias utilizes ultrasonic energy to ensure adequate filling of the vias. The semiconductor is supported on a block and heated and subjected to ultrasonic energy greater than 25 kHz as aluminum is sputter deposited onto the substrate surface. The frequency of the ultrasonic energy is varied from 35 to 42 kHz as the aluminum is deposited in order to avoid standing wave or node formation along the substrate surface. This permits for an efficient high quality application of aluminum and filling of vias on a semiconductor substrate.