Challenges in Dry Etching of AlN & AlScN for BAW Filters
Oct 30, 2019Piezoelectric thin films are commonly used as the resonator in bulk acoustic wave (BAW) devices for RF filtering in handsets. AlN is the base piezoelectric material but recent trends involve doping heavily with scandium (Sc) to improve the coupling efficiency. Device makers are currently working with Sc content in the range 6-30at%. As feature sizes have reduced over time the industry has also moved from wet etching to dry etching to define the piezoelectric layer and the associated metal electrodes. Unfortunately, increasing the Sc makes dry etching more problematic because of the low volatility of scandium halides relative to those of Al and N. This Webinar focuses on these dry etch challenges and presents solutions based on the use of a high density plasma etch module called Synapse. Etch data will include performance comparisons with more mainstream ICP type reactors.