Vertical integration technologies for optical transmissive 3-D microscanner based on glass microlenses
This paper describes crucial technological aspects of development of an optical, transmissive, vertically-integrated 3-D microscanner: chip-level bonding of micro-optical components and wafer-level anodic bonding of deeply structurized substrates. We present two methods of hybrid integration of glass microlenses with fragile movable parts of silicon microactuators, based on glass frit bonding or direct thermal bonding, that have been experimentally validated in terms of bonding strength, anodic bonding compatibility and change of optical performance of microlens. We also demonstrate the 3D stacking technology, based on sequential multi-level anodic bonding, successfully tested with deeply structurized silicon/glass wafers. Presented methods are of general importance for vertically integrated M(O)EMS Si/glass devices.