A METHOD FOR FORMING A MICROMECHANICAL DEVICE

摘要

A method is disclosed for forming a micromechanical device. The method includes providing sacrificial layer (14) on a substrate, providing a first structural layer (18) on the sacrificial layer and removing a portion of the first structural layer in an area intended for a hinge (16A,B). Then, a second structural layer (20) is provided over the first layer and in the removed area for the hinge. The second layer is preferably deposited directly on the sacrificial layer in this area. Last, a metal layer (22) is deposited and the various layers are patterned to define a micromechanical device having one portion (e.g. a mirror plate) more stiff than another portion (e.g. hinge). Because a portion of the reinforcing layer is removed, there is no overetching into the hinge material. Also, because the metal layer is provided last, materials can be provided at higher temperatures, and the method can be performed in accordance with CMOS foundry rules and thus can be performed in a CMOS foundry.