Handbook of Silicon Based MEMS Materials and Technologies

Chapter Thirty Six. Non-destructive Bond Strength Testing of Anodic Bonded Wafers

Bonding strength and, related to this, hermeticity are the main quality aspects in wafer bonding. This is also true for anodic bonding, which is widely used because it is normally a very robust and reproducible process. The anodic bond in most cases is very strong, and due to the different elastic properties of glass and silicon (Young’s Modulus, Poisson ratio) pull testing and crack propagation tests are almost impossible to perform.^[1] However, here also process influences, such as surface roughness, residuals of previous processing steps, aging of the electrodes due to the sodium in the glass wafers, or cracks in the glass, can lower the bonding strength locally ...