Experiments on the Release of CMOS-Micromachined Metal Layers

Figure 3

Microphotograph of a CMOS-MEMS membrane released with ammonium fluoride ($\text{N}{\text{H}}_4\text{F}$). Etching time was 40 minutes. The etching reached the substrate at 7.6 $\mu$m depth, but the passivation layer was damaged.