SACRIFICIAL WAFER BONDING FOR PLANARIZATION AFTER VERY DEEP-ETCHING

A new technique is presented that provides planarization after a very deep etching step in silicon. This offers the possibility for as well resist spinning and layer patterning as realization of bridges or cant ilevers across deep holes or grooves. The sacrificial wafer bonding te chnique contains a wafer bond step followed by an etch back. Results o f polymer bonding followed by dry etching and anodic bonding combined with KOH etching are discussed. The polymer bonding has been applied i n a strain based membrane pressure sensor to pattern the strain gauges and to provide electrical connections across a deep corrugation in a thin silicon nitride membrane by metal bridges.