Single-crystalline Silicon on Quartz (SOQ) Wafer by Ultra-low Temperature (100℃) Wafer Bonding and Thinning Approaches

摘要

Single-crystalline silicon films have been prepared on synthetic quartz (fused quartz or quartz glass) substrates by ultra-low temperature wafer bonding and thinning approaches. The wafer surfaces treated only by RCA1 process showed a relative low initial bonding energy of 0.17 J/m~2. Though the bonding strength can be raised to 14 J/m~2 after 350℃ annealing for 4 h, the severe warpage of bonded wafer led to the poor total thickness variation (TTV) of SOQ wafers (TTV > 10 μm) after thinning. However, if the wafer surfaces treated with RCA1 process, and followed by O_2 plasma treatment for 15 sec, the initial bonding energy can be raised to 0.83 J/m~2. After the bonded wafer annealed at 100℃ for 16 hrs, the bonding strength increased rapidly to 13.3 J/m~2 with still a low warpage of 2.5 μm. The SOQ wafers fabricated by the ultra-low temperature bonding, lapping and polishing showed relative good TTV of less than 4 μm.