Controlled sacrificial sidewall surface micromachining for the release of high length-to-thickness aspect ratio bridges
A surface micromachining technique for the release of high length-to-thickness aspect ratio (800:1) bridge structures is presented. During a timed etch release, the remaining side wall geometry of the sacrificial layer provides intrinsic support for the structural layer. The micromachining process itself is an equipment limited procedure in which the wet etchant for the sacrificial layer is replaced in solution (i.e., in situ) with a supportive photoresist layer. Once in solid form, the photoresist is removed via ashing in an oxygen plasma. This combination of controlling the sidewall etch profile of the sacrificial layer and its removal technique results in the successful release of bridge structures, which are 4000 μm long and 5 μm thick, with a 2 μm suspension gap.
|Journal||Journal of Vacuum Science & Technology B|
Raum, C.R. (Christopher R.), Tait, R, & Gauthier, R. (2010). Controlled sacrificial sidewall surface micromachining for the release of high length-to-thickness aspect ratio bridges. Journal of Vacuum Science & Technology B, 28(6), 1195–1201. doi:10.1116/1.3503612