High speed micro welding of glass and silicon

Joining of glass and silicon is often needed in integrated circuit packaging. Methods like anodic bonding and fusion bonding are used for joining silicon and glass wafers currently. Compared to these methods, laser joining can provide higher flexibility using easily defined bond regions that are fast to produce and only localized heating can be used. The whole wafer is not exposed to high temperature or electrical field in the laser joining, which is very important in certain applications. We were able to produce good quality welding seams that were less than 20 um wide. A picosecond pulsed fibre laser was used in tests and processing speeds from 100 mm/s to 2 m/s were tested. The high processing speed makes the laser joining a competitive method, as a whole wafer can be processed in sufficient time