Low Temperature MEMS Manufacturing Processes: Plasma Activated Wafer Bonding

Abstract

AbstractThis paper introduces a new technology: low temperature plasma activated wafer bonding. In this process, the wafers are submitted to a plasma treatment prior to bringing them into contact for bonding. The surface activation allows process temperatures ranging from room temperature to maximum 400°C. For Si direct bonding using plasma activation the Si bulk fracture strength is reached after a thermal annealing of 1 hour at 300°C, much lower than the annealing temperature used for the standard process without plasma activation (∼1100°C). Experimental results illustrating the main benefits of the process are presented. The process was successfully applied also for bonding other materials than silicon.