Release-control structure for post-process release of a micromachined cantilever

This paper presents a cost-effective method of obtaining intact, released oxide/poly cantilever beams (using bulk micromachining), within the constraints of simple post-processing of a standard CMOS fabrication process. Extensions to the basic cantilever are used to prevent the main oxide/poly beam from bending upwards until the main cantilever is completely released from the Si beneath. The cantilever and extensions are designed based on etch anisotropy in TMAH 25 wt% at 80/spl deg/C. The connection tether angles are designed to be at an angle where the underetch rate of the etchant is greatest.