K. Ikeuchi, M. Takahashi, Osaka University, Ibaraki, Japan
A glass plate having a surface layer in which Na ions were replaced with Ag ions was anodically-bonded to a silicon plate to investigate the feasibility of bonding by utilizing the migration of a cation other than alkali ions. The anodic bonding after the Ag/Na replacement of the glass surface was successfully achieved under the same bonding conditions as those employed when the replacement was not applied. When a joint was exposed to an electric field in the opposite direction to that applied during the bonding, the Ag/Na replacement prevented the accumulation of Na ions at the interface due to their migration driven by the opposite electric field, and the consequent degradation in the joint strength. Although the opposite electric field brought about the precipitation of metallic Ag particles in the glass near the bond interface, no significant influence on the joint performance was observed when the Ag/Na replacement of the glass surface was applied.
Summary: A glass plate having a surface layer in which Na ions were replaced with Ag ions was successfully anodic-bonded to a silicon plate by exploiting the mibration of Ag ions instead of Na. When the joint was exposed to electric field opposite to that applied during the bonding, the Ag/Na replacement of the glass surface prevented the accumulation of Na ions at the interface due to the migration driven by the opposite electric field, and the consequent degradation of the joint strength.