Large-Area X-Ray Topographs of Lattice Undulation of Bonded Silicon-On-Insulator Wafers

X-ray topographs of bonded silicon-on-insulator (SOI) wafers were obtained using a synchrotron large X-ray beam. Wrinkled patterns in a micrometer scale were observed all over the wafers. Crumpled patterns were also observed, which were related to the lattice undulation at the average spatial interval of about 6 mm with the tilt angle of the order of ten arcsec. From the comparison with the topographs between the SOI layer and the substrate, it was also found that the warpage of the lattice plane of the SOI layer was different from that of the substrate.