Automatic counting of packaged wafer die based on machine vision

This paper presents a robust method to automatically determine the number of packaged dies in the residual wafer image, in which most dies have been removed and packaged. We propose the die segmentation region detection algorithm based on vertically and horizontally cumulative histograms and die detection algorithm based on YCbCr color space. The abnormal cases of fractional dies in the wafer boundary and dropped dies during packaging are considered in the proposed method as well. In the experimental results, the proposed method achieves 100% accuracy in counting the number of packaged dies in the ten test cases.