Webinar

Glass wafers are increasingly adopted as substrates for advanced semiconductor packaging, including glass interposers and TGV-based platforms, where surface waviness, flatness, and roughness are critical for bonding and alignment quality. In this study, Digital Holographic Microscopy (DHM) was applied to characterize the surface topography of a 300 mm bare glass wafer over a large area. Using a 1.25× objective with a 7 × 14 stitching array (98 images, 5.02 µm pixel resolution), full-field height maps were acquired without mechanical Z-scanning and decomposed into waviness and roughness components for quantitative analysis.

Frontside/backside comparison revealed an anti-correlated surface morphology, indicating corrugated deformation through the wafer thickness rather than simple bow or tilt. Local defect features — including bump-like deformations (~90 nm) and crack-like defects (~70 nm depth, ~25 µm width) — were also identified via line profile analysis. These results demonstrate DHM as a practical, non-contact metrology platform for large-area glass wafer inspection with nanometer-scale vertical sensitivity.