American Association for Crystal Growth, Western Regional Section

Hydrophobic wafer bonding using H+ implantation splitting

C. Miclaus, M.S. Goorsky, Y.M. Kim, H.J. Kim, Y.H.Xie,
University of California, Los Angeles
Department of materials Science and Engineering
Los Angeles, CA 90095-1595

 

The structural changes that accommodate wafer splitting after hydrogen implantation of silicon wafers and the transfer of split layers to a handle substrate were investigated. (004) silicon substrates were implanted with hydrogen with a dose that ranged from 5x10¹⁵cm^-2 to 8x10¹⁶cm^-2 and energies of either 30kV or 140kV. The changes in the implanted layer properties were investigated using high resolution x-ray diffraction and atomic force microscopy after annealing at 100°C - 300°C for short times. For annealing temperatures up to 150°C, the implant profile did not change appreciably nor did the surface roughness increase. Annealing at 200°C or higher for 10 minutes or more led to increased surface roughness and a change to the implant profile, although blister formation did not occur. Higher surface roughness is not conducive to successful wafer bonding, so these measurements helped to determine the annealing sequence that is appropriate for bonding a hydrophobic implanted wafer with a hydrophobic handle wafer. Hydrophobic bonded wafers were successfully fabricated with the transferred layer showing similar structural properties as a thin epitaxial film of the same thickness.