Time-Multiplexed Alternating Plasma Etching of Piezoelectric Materials

Piezoelectric materials, such as Sc<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.2</inf>Al<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.8</inf>N and PZT, are key building blocks for wave filters, which has applications in 5G communications. In this work, we demonstrate a time-multiplexed alternating process for the plasma etching of piezoelectric materials. Compared with the traditional plasma etching method, the plasma etching results, such as has uniformity, residuum, and bottom metal electrode loss/damage, can be better controlled in time-multiplexed alternating process.