Comparison of the mechanical properties of low temperature bonded test samples

The fabrication of silicon microelectromechanical components (MEMS) involves joining of two or even more wafers. During the last years special focus was given on low temperature waferbonding. In this paper an universal test wafer is proposed that can be applied for bond strength quality monitoring. The investigated wafers in this study were activated, wafer-bonded, annealed at 200°C or 400°C and subsequently tested with respect to dicing yield, tensile strength, fracture toughness, and surface energy. The wafer bonding was performed by seven different partners. It was shown that the bonding quality varied significantly for the different activation technologies even for the same annealing conditions. In general the special treated samples exceed the values of a RCA pre-treated reference sample annealed at 200°C. Some of the activation technologies were able to create bonds that reached the value of RCA pre-treated reference samples, which were annealed at 900°C.