Improved Image Processing Algorithms for Microprobe Final Test

With the rapid development of the integrated circuit (IC) industry, testing of IC chips is becoming more and more important. A chip probe final test is an important means of final chip testing, which makes use of contacts between probes and bumps on the chip for electrical connections of the test instrument and the chip, through which the electrical characteristics of the chip are tested one by one. The IC final test is directly completed on the entire packaging wafer before the packaging wafer is cut into single die. This complete testing of the whole wafer before dicing can greatly improve the efficiency of the final test. The precise alignment of probe and chip bumps is an important aspect of the final test process. In this paper, image processing is carried out based on the rectangular frame of the chip surface, for which the rectangular box image-processing algorithm is designed. The chip image showing the deflection angle is acquired, and the offset distance is calculated. The rectangular box algorithm based on the principle of the Hough transform detects the orientation that is used to determine the offset of the rectangular frame. The detection accuracy and efficiency of the algorithm is evaluated, and it is shown that the image-processing algorithm of the chip alignment is improved significantly. An efficient automatic probe final test of packaging wafers can finally be achieved.