Evaluation of Thin Film Indium Bonding at Wafer Level
needed. By an optimized patterning of the evaporated indium film and the lid, surface hermetic bonding on wafer level is reached without exceeding 140 °C in any step of the procedure. Different designs of the indium metallization and lid were tested to improve bond strength while keeping the same bonding parameters. By depositing an adhesion layer of CrAu on the lid, the bond strength can be increased by 30 % compared to the one of indium to glass bonding. Another way to increase bond strength by 40 % is to profile one bonding surface in such a way that the indium oxide breaks at multiple places within the deposited area. Hermeticity is proven for all different designs.