Automatic Test System for Wafer Level Probing Photodiode of Optical and Electrical Parameters of Array Dies

The opto-electrical test system for photodiode arrays was designed using a customized SUSS MicroTec PA200 probe station. The system allowed 100% electrical and optical testing of wafers and dies before die attach. It accommodated single multi-pixel dies or wafers up to 150 mm in diameter, in diced or non-diced form. The probe card contacted multiple pixels of the wafer/die simultaneously. The pattern recognition system allowed automatic alignment of the wafer/die and precise positioning of the probe needles on any group of contact pads. The 150-mm integrating sphere coupled to the white-spectrum or monochromatic light source was used to provide a uniform illumination of the photodiode array. This enabled accurate measurements of the leakage current, spectral sensitivity, response uniformity, and other optical and electrical parameters. Sample results from opto-electrical tests of a wafer with multi-pixel photodiode arrays are presented in this work. The forward voltage uniformity across the wafer was measured to be better than plusmn3% and the photo current response uniformity for 3072 pixels was better than 1%.