Optical Fiber-Based Confocal and Interferometric System for Measuring the Depth and Diameter of Through Silicon Vias

To measure the depth and diameter of through silicon vias simultaneously, a novel method based on spectral-domain interferometer and confocal microscope is proposed and realized. Most parts of the measurement system are constructed with optical fiber components for flexible configuration and easy alignment. According to the measurement results and performance evaluation, the mean values of the diameter and depth were 6.07 mu m and 48.255 mu m with the expanded uncertainties of 0.20 mu m (k = 2) and 37 nm (k = 2), respectively.