Early Observations between Magnet and Film Properties for AlN Deposition by Reactive Magnetron Sputtering

Abstract

This paper reports the findings taken from early experimentation towards the development of high quality AlN layers deposited using physical vapor deposition (PVD)-production tool. In these experiments, the magnetron was equipped with a rotating magnet to enable full-face target erosion. Four magnet designs were tested with various nitrogen (N2) ratios in the gas mixture with argon (Ar). These results show the thickness non-uniformity for AlN film trending across a range of N2 ratios differs with magnet design. Similarly, it has been verified that the N2 ratio is an effective knob for stress control of an AlN film and that the measured in-film stress trends linearly with N2 ratio for all four magnet designs. Using an optimized magnet design and finely tuned process conditions, these early experiments have shown highly uniform AlN films on 200 mm Si wafer with a strong c-axis orientation and tunable stress, which help the learning and development of AlN film for applications in MEMS and BAW devices.