Bonding performance in atomic diffusion bonding of wafers using amorphous Si thin films with smooth surface

Amorphous Si films with a low surface roughness of 0.13 nm were used to examine the bonding performance of atomic diffusion bonding of quartz glass wafers at room temperature in vacuum. The high bonding strength was achieved for films with thickness δ of 2-50 nm: the blade could not be inserted between the bonded wafers. Using a vacuum chamber with a base pressure of 1 × 10-6 Pa, the great bonding strength was maintained even with waiting time in vacuum of as long as 3.6 × 103 s from film deposition to bonding. The excellent bonding performance was almost equal to that achieved using Ti films.