A Fully Automatic Calibration for Vision-Based Selective Compliance Assembly Robot Arm and Its Application to Intelligent Wafer Inspection Scheduling

This study provides a complete Selective Compliance Assembly Robot Arm (SCARA) wafer inspection system. This system mainly includes two phases. In the first phase, a SCARA manipulator acts as an inspection application platform, and a depth camera is used to position the position vector of an inspection point and a cassette together with a single-axis visual frame so that SCARA can automatically perform calibration in the working area. In the second phase, the wafer ready for inspection is optimized for procedure sorting to perform all detection items in the shortest time when SCARA is in the process of inspection. This study has solved the problem of calibrating positions of a manipulator and a working area with consumption of manpower in a traditional wafer inspection field in such a way that the manipulator can complete a predetermined task with the economic benefits of the inspection center without colliding with the working area. In addition, optimized scheduling reduces the time for the manipulator to complete all inspection tasks to allow more wafers to be inspected per unit time. Finally, the relative positions of all inspection points are automatically calculated by the manipulator by placing SCARA in a field not calibrated by the inspection points. The predefined wafer inspection scheduling is sent to the system for optimization calculation, and the experimental results are presented by SCARA.