Direct bonding of Si wafer pairs with SiO₂ and Si₃N₄ films with a fast linear annealing

2000 Å-SiO₂/Si(1 0 0) and 560 Å-Si₃N₄/Si(1 0 0) wafers, that are 10 cm in diameter, were directly bonded using a rapid thermal annealing method, so-called fast linear annealing (FLA), in which two wafers scanned with a high-power halogen lamp. It was demonstrated that at lamp power of 550 W, corresponding to the surface temperature of ∼ 450°C, the measured bonded area was close to 100%. At the same lamp power, the bond strength of the SiO₂∥Si₃N₄ wafer pair reached 2500 mJ/m², which was attained only above 1000°C with conventional furnace annealing for 2 h. The results clearly show that the FLA method is far superior in producing high-quality directly bonded Si wafer pairs with SiO₂ and Si₃N₄ films (Si/SiO₂∥Si₃N₄/Si) compared to the conventional method.