Automatic alignment and testing system for wafer with ball grid array

In order to develop automatic testing system for wafer with ball grid array, a method of pattern matching using the feature of ball grid array is proposed, and a new testing system with optical system and motion control system is integrated. It was found that the accurate position of wafer can be found before wafer probe testing, and the relative position between probe array and every chip can be calculated. The wafer can be aligned precisely by image process and motion control. Results show that the automatic testing of wafer can be carried out, and the electrical properties of the chip can be effectively evaluated.