In recent years, MEMS device technology has evolved further and has become indispensable for various sensors and actuators. In particular, the use of piezoelectric materials, which are expected to contribute to miniaturization and higher performance of MEMS, is expected. This section introduces the manufacturing process of piezoelectric MEMS and the required technology, using PZT, which has excellent piezoelectric properties among piezoelectric materials.
Piezoelectric MEMS fabrication flow
1. Formation of piezoelectric element
A piezoelectric element is formed by sandwiching a few μm of ferroelectric between noble metal electrodes.
The sputtering equipment provided by ULVAC can stably form the world’s highest level PZT sputtered film. (Compatible with film deposition on CMOS: PZT film deposition temperature <500 ° C) PZT full stack (upper and lower electrodes + PZT) can be consistently deposited with a multi-chamber.
The lower electrode is separated by dry etching. It realizes high uniformity and precise end point detection so that the material under the lower electrode is not cut too much. (Distribution <3% @ 8inch)