Development of High-Resolution Nuclear Emulsion Plates for Synchrotron X-Ray Topography Observation of Large-Size Semiconductor Wafers

Abstract

Characterization of defects in semiconductor wafers is essential for the development and improvement of semiconductor devices, especially power devices. X-ray topography (XRT) using synchrotron radiation is a powerful methods used for defect characterization. To achieve detailed characterization of large-size semiconductor wafers by synchrotron XRT, we have developed nuclear emulsion plates reaching a high-resolution and wide dynamic range. We have shown that higher-resolution XRT images could be obtained using emulsions with smaller iodobromide crystals, and demonstrated clear observation of threading edge dislocations in a SiC epitaxial layer having small contrast. Furthermore, we demonstrated XRT image acquisition for almost all of a 150-mm SiC wafer with one plate. Our development will contribute to advances in electronic materials, especially in the field of power electronics, in which defect characterization is important for improving the performance and yield of devices.

Effects of proton implantation for expansion of basal plane dislocations in SiC toward suppression of bipolar degradation: review and perspective

“…[8][9][10] Therefore, development of wafer inspection technologies has been explored to screen through poor quality wafers. 7,[10][11][12][13][14][15][16][17][18] Over the past two decades, basal plane dislocations (BPDs) in 4H-SiC substrates have emerged as crucial defects in SiC wafers. Bipolar degradation in 4H-SiC PN diodes has emerged as a significant concern affecting their operational longevity.…”