Microwave plasma cleaner design for semiconductor fabrication and materials processing laboratory use

Abstract

This paper describes a microwave plasma cleaner designed and built for use in integrated circuit fabrication and materials processing laboratories. It is a much less expensive alternative to RF plasma cleaners because of the fact that very inexpensive and readily available household microwave oven is utilized to generate the microwave power to produce the plasma in the process chamber. The process chamber is an inverted Pyrex bowl placed on a metal base plate and is evacuated by a rotary vane vacuum pump capable of reaching milliTorr ultimate vacuum. The system built is portable on wheels, and employs two Rotameter flow meters with fine needle valves to control gas pressure and composition fed into the process chamber. Pressure is monitored with a digital thermocouple vacuum gauge. Uniform plasma is obtained at operating pressures of 100-1000 milliTorr range. Currently the microwave plasma system built is being used to plasma treat the gold bonding pads of package and MEMS chips to facilitate organics free surfaces and improve the quality in wire bonding. However, such a system can easily be adapted to serve as plasma assisted dry etcher. © 2011 American Society for Engineering Education.