Development of local ambient gas control technologies for atmospheric MEMS process

This paper reports a local ambient gas control technology for atmospheric MEMS processes, especially plasma processes, using a new local ambient gas control head. First, the local ambient gas control with this head was investigated by a computational fluid dynamics code. After confirmation of the safe evacuation and the feasible cleanness level, which is comparable to the impurity level in semiconductor grade gas (below 10 ppm), a prototype apparatus was fabricated based on the simulation results. Measuring gas distribution by a gas analyzer, a O2 meter and a dew point meter, the local ambient gas control was confirmed experimentally. Next, H2 plasma generation was achieved in open air with H2 concentrations of 0–100 % even above the explosive limit in air (4.1 %) safely. In addition, Cu reduction and SiO2 etching by H2 plasma were demonstrated in open air. These results show high potential of our local ambient gas control technology for atmospheric MEMS processes.