A die-scale micromachining process for bulk PZT and its application to in-plane actuators

Bulk ceramics (including PZT) are important materials for electronic and microsystem packaging or device applications, but they are usually difficult to pattern lithographically. A fabrication process combining lithography, electroplating, batch mode micro electro-discharge machining (/spl mu/EDM) and batch mode micro ultrasonic machining (/spl mu/USM), LEEDUS, has been developed to provide die-scale pattern transfer capability from lithographic masks onto ceramics, glass or other brittle materials. A related process (SEDUS) uses serial /spl mu/EDM and omits lithography. Feature sizes of 25 /spl mu/m have been micromachined on the glass-mica (Macor/spl trade/) ceramic plate with a 4.5/spl times/4.5 mm/sup 2/ die size, 34 /spl mu/m cutting depth, and 18 /spl mu/m/min machining rate. As a demonstration an octagonal spiral shaped in-plane actuator was fabricated from bulk PZT using this process. A device of 20 /spl mu/m thickness and 450 /spl mu/m /spl times/ 420 /spl mu/m footprint produces a displacement of /spl sim/2 /spl mu/m at 40 V.