Bonding of a Si microstructure using field-assisted glass melting

This paper reports a novel micro-bonding process based on field-assisted glass melting at room temperature. The phenomenon of local melting of a glass is also investigated. A cantilevered structure with a sharp tip is contacted with a metal-coated glass, and a voltage of few volts is applied between the tip and the metal thin film. As a result, the glass in the vicinity of the tip is melted. It is considered that a high electric field at the tip diffuses the metal atoms into the glass and forms ionic liquid. This is only observed on the glass coated with a thin Cr film among Al, Au, Cr and Ti thin films. This micro-melting process is applied to the assembling of silicon microstructures on a glass substrate. Cantilevered silicon structures with a tip and a microstructure are fabricated by microfabrication technology. During this melting reaction, external force is applied and the tip gets buried; as a result, the cantilever is bonded with the glass substrate. The support of the cantilever beam is mechanically broken, which can leave the microstructure on the glass substrate.