RATE-PROCESSES DURING ANODIC BONDING

The rate processes which occur during anodic bonding are modeled using data from various studies. For a given materials system, the process occurs at constant total charge transfer. The observed activation energies are consistent with dc conduction in the glass. The charge transfer required for bonding to aluminum anodes decreases with increasing alkali content of the glass, which is probably due to increasing solubility and mobility of aluminum in depletion layers with higher vacancy contents. The voltage required for bonding at constant time and varying temperature is also consistent with constant charge transfer. The kinetic data are consistent with an electrochemical oxidation model where the rate of bonding is limited by the rate of establishment of the depletion layer.