Multi-wafer Bonding, Stacking and Interconnecting of Integrated 3-D MEMS Micro Scanners

In this work we describe the bonding and contacting of a micro machined vertically integrated 3-D micro scanner, which is a key- component for a number of scanning imaging micro systems, such as confocal microscopes on- chip or optical coherence tomography (OCT) probes for micro endoscopy. The 3-D micro scanner is composed of two electrostatic silicon MEMS micro actuators which are vertically aligned and bonded with glass and ceramic components to create hermetically sealed cavity for scanning micro lenses. In addition, the through wafer vias (TWV) technology is employed to establish electrical connection from the top to the bottom through a stack of two SOI wafers, one glass wafer and one ceramic wafer. Presented methods are of general importance for various silicon-based vertically integrated devices.