A flexible built-in gettering layer prepared by hydrophobic Si wafer bonding

Abstract

The bonding interface of bonded hydrophobic Si pairs has been found to be a strong gettering layer. By thinning one wafer of the pair, the location of the gettering layer with respect to the defect-free Si surface layer where devices are fabricated can be varied from more than 500 μm to deep-submicrons. Secondary ion mass spectrometry and simulation results suggest that F atoms at the interface are primarily responsible for the gettering effect via Au-F ion pairing. It appears that a significant segregation of Au to the hydrophobic bonding interface is observed during annealing at 900 °C. These results are compared to gettering of Au by a hydrophilic bonding interface.