US Patent 7214324 Technique for manufacturing micro-electro mechanical structures

A technique for manufacturing a micro-electro mechanical structure includes a number of steps. Initially, a cavity is formed into a first side of a handling wafer, with a sidewall of the cavity forming a first angle greater than about 54.7 degrees with respect to a first side of the handling wafer at an opening of the cavity. Then, a bulk etch is performed on the first side of the handling wafer to modify the sidewall of the cavity to a second angle greater than about 90 degrees, with respect to the first side of the handling wafer at the opening of the cavity. Next, a second side of a second wafer is bonded to the first side of the handling wafer.