Improvement of Photo-Misalignment in Patterned Wafer Bonding Process for Silicon-on-Insulator Device

We have found that the photo-misalignment problem in patterned and bonded silicon-on-insulator (PBSOI) was closely related to the bonding process. We examined the stress effect on photo-misalignment using a vacuum bonding system. Photo-misalignment was critically dependent on the distance between bonding plates. Good alignment, which is less than 0.1 mu m and has uniform direction within a wafer, could be achieved with a 1.4 mm separation width between bonding plates.