Direct Homo/Heterogeneous Bonding of Silicon and Glass Using Vacuum Ultraviolet Irradiation in Air

We develop a cost-effective vacuum ultraviolet (VUV) irradiation in air combined with an in situ bonding process. The whole bonding process does not require high vacuum environments. Strong bonding strengths for Si/Si, Si/glass, and glass/glass pairs were achieved with the assistance of annealing at 200°C. There was no crack or defect at the bonding interfaces. The excellent optical transparency of the bonded glass/glass pairs was demonstrated in the UV-visible range. On the basis of the surface and bonding interface characterizations, the low-temperature bonding mechanism was investigated and discussed. Similar to the plasma activated bonding, the internal water stress corrosion plays a crucial role in the mechanical evolution of bonding interface between the VUV irradiated surfaces during annealing. This facile bonding method offers great potential for silicon- and glass- based homo/heterogeneous integrations in microelectronics, optoelectronics and microfluidics.