Direct Bonding Energy Measurement Under Anhydrous Atmosphere

Bonding energy represents an important parameter for direct bonding applications as well as for the elaboration of physical mechanisms at bonding interfaces. Measurement of bonding energy using double cantilever beam (DCB) under prescribed displacement is the most used technique thanks to its simplicity. After a short description of this technique and its advantages, the different mathematical developments which link the debonding length to the bonding energy will be presented and discussed. General main setup parts influencing energy measurements will also be reviewed and different ways to minimize the bonding energy error will be proposed. Among them, the measurement in humid atmosphere seems to be the main one. Indeed, usually, the bonding energy measurements are done in standard atmosphere with relative humidity (RH) above 40%. Therefore, for hydrophilic silicon or silicon oxide bonding, the bonding energy values are strongly impacted by the water stress corrosion at the bonding interface as previously shown by many authors. This paper will focus on DCB measurements which have been performed under anhydrous atmosphere in order to minimize the water stress corrosion. Details of this new measurement setup have been published elswhere.