Humidity Effects on Substrate Bonding for Silicon-On-Glass

Glass-to-silicon bonding quality has been studied as a function of air relative humidity in a pre-bonding tool. Two bond-activation techniques, wet and plasma, were used. Optimum ranges of air humidity that ensure high bonding yield are determined. The bonding is finalized by annealing and types of defects appearing in the cases of low and high humidity are indicated. Results prove that humidity control is required for high yield glass-to-silicon bonding.