Calibration of Wafer Handling Robots: A Fixturing Approach

Semiconductor manufacturing industry requires highly accurate robot operation with short install/setup downtime. We develop a fast, low cost and easy-to-operate calibration system for wafer-handling robots. The system is defined by a fixture and a simple compensation algorithm. Given robot repeatability, end-effector uncertainties, and the tolerance requirements of wafer placement points, we derive fixture design and placement specifications based on a deterministic tolerance model. By employing the fixture-based calibration, we successfully relax the tolerance requirement of the end-effector by 20 times.