Blade Test in Atmospheric-Pressure Ar Gas to Characterize Bonded Interface Fabricated Using Atomic Diffusion Bonding

Abstract

A blade test was applied in atmospheric-pressure Ar gas for wafers bonded using atomic diffusion bonding processing. We assessed the variation of the values of surface free energy at the bonded interface γ calculated, for convenience, from the debonding length. For interfaces bonded using thin Zr and Ti films, γ measured in Ar maintained the initial value γ0(Ar) in the initial region of observation time t and started decreasing as t increased further. Results indicate that γ0(Ar) corresponds to the value without water stress corrosion effects. The initial value of γ measured in air with a higher blade insertion-speed was almost equal to γ0(Ar). Result obtained for wafers bonded using Al2O3 films were almost identical to those obtained using metal films. However, γ for wafers bonded using ZrO2 films did not maintain their initial values. They decreased gradually as t increased, even in Ar, suggesting high water stress corrosion effects.