Reversible wafer-level bonding at room temperature [MEMS applications]

This paper reports novel methods for reversible, room-temperature, wafer-level bonding that is applicable for MEMS packaging and fabrication processes. A self-assembled monolayer (SAM) that had been used to join an elastomer and a metal (Au) was decomposed using elevated temperature, desorbed using electrochemical reduction, or pulled apart by mechanical forces. Using any of these methods, the bond was broken between the elastomer and the metal so that previously bonded wafers could be detached. These technologies are potentially useful for processing sequences in which only temporary bonding is required, such as the formation of caps to protect pre-released MEMS devices during a wafer-dicing process or for reversible interconnections.