Micro thermal shear stress sensor based on vacuum anodic bonding and bulk-micromachining

This paper describes a micro thermal shear stress sensor with acavity underneath, based on vacuum anodic bonding and bulkmicromachined technology. A Ti/Pt alloy strip, 2$mu $m$times$100$mu $m, is deposited on the top of a thin silicon nitridediaphragm and functioned as the thermal sensor element. By usingvacuum anodic bonding and bulk-si anisotropic wet etching processinstead of the sacrificial-layer technique, a cavity, functioned asthe adiabatic vacuum chamber, 200$mu $m$times $200$mu $m$^{}times $400$mu $m, is placed between the silicon nitride diaphragmand glass (Corning 7740). This method totally avoid adhesion problemwhich is a major issue of the sacrificial-layer technique.