A three-dimensional silicon shadowmask for patterning on trenches with vertical walls

This paper proposes a direct metal patterning method on three-dimensional structures with vertical side walls. It uses a 3-D multi-height silicon shadow mask made by double-side Deep Reactive Ion Etching (DRIE). Aluminum has been successfully patterned on the top, bottom and vertical side walls of 280mum wide trench with a depth of 250mum by sequentially tilting the wafer at three different angles during evaporation. The resulting tracks exhibited good isolation between adjacent metal patterns and with the resistance of the track between top and bottom of trench measured at 3.4Omega.