A new methodology for inspection of TSV (Through Silicon Via) process wafers is developed by utilizing an optical diffraction signal from the wafers. The optical system uses telecentric illumination and has a two-dimensional sensor in order to capture the diffraction light from TSV arrays. The diffraction signal modulates the intensity of the wafer image. Furthermore, the optical configuration itself is optimized. The diffraction signal is sensitive to via-shape variations, and an abnormal via area is analyzed using the signal. Using the test wafers with deep hole patterns on silicon wafers, the performance is evaluated and the sensitivities for various pattern profile changes were confirmed. This new methodology is available for high-volume manufacturing of the future TSV-3D CMOS devices.© (2011) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.