Piezoelectric MEMS microphone with cantilevered separation

The etching process is segmented into two distinct stages: first creating perforations through the entire thickness at selected positions, then creating partial etches between the perforations that extend less than the entire thickness. This segmentation allows the break line to be formed through controlled partial etching rather than continuous etching, improving both the cleanliness of the break and the precision of the gap formation between cantilevers.

The perforations are created in advance at selected positions along the intended break line. These pre-formed holes serve as stress concentration points and etching initiation sites, guiding the subsequent partial etching process to follow the desired path. This preliminary action ensures that the break occurs cleanly at the intended location without requiring complex continuous etching patterns.

Perforations and partial etches are created in advance at precisely controlled positions along the intended break line. These pre-formed features act as stress concentration points that guide where the thermal cycling-induced breaks will occur. The preliminary structuring ensures that when thermal cycling is applied, the breaks happen exactly where needed, combining ease of the thermal cycling process with precise location control.

The piezoelectric film layer is selectively modified at different locations: perforations are created at specific positions to initiate breaks, while partial etches are created between the perforations to define the break path. This local differentiation ensures that thermal cycling produces breaks only at the desired locations with controlled geometry, rather than random breaks throughout the film.