Real-time image segmentation system for IC die patterns

Abstract

A real-time image segmentation system realized for extracting the bond pads in IC die images is presented. The system can work in current IC manufacturing machines with binary-level pattern recognition systems under nearly uniform lighting conditions. The system uses a general-purpose digital signal processor DSP56001 to realize the global thresholding algorithm, and most of the functional blocks are implemented using programmable logic devices. The selection of the thresholding algorithm is based on the characteristics of industrial IC die images. IntroductionImage segmentation is a process which divides images into several meaningful regions so that the segmented image can be used for further analysis or interpretation. The segmentation process is an important early stage in image analysis and pattern recognition; for example, a well-chosen threshold value is of paramount importance to a binary-level pattern recognition system. Bhanu et al. (1990) described a VLSI design to implement a real-time segmentation processor. However, a real-time implementation of a segmentation algorithm is quite complex and each algorithm may need dedicated hardware. As a result, redesign of a segmentation processor is required when a new segmentation algorithm is proposed. On the other hand, if the segmentation algorithm is implemented using a digital signal processor (DSP), then the realization of a new algorithm may only require modification of software.In the IC manufacturing industry, the advances in application-specific and semicustom ICs has led to the evolution of high lead-count and high-density semiconductor packages. Hence, the bond pads have become smaller and smaller and the lead frame narrower and narrower. This provides challenges for the wire bonding technology. Shah et al. (1988) identified several new technological requirements in the design of the next-generation of wire bonders. These include high placement accuracy and minimum set-up time. These requirements are partly related to the pattern recognition system for the bonding machines, where the pattern recognition system has to locate the bond pads or bonding leads quickly and accurately.Since modern wire bondedrs are capable of bonding more than ten wires per second, in order not to degrade the machine throughput a fast and reliable pattern recognition system is urgently needed. Binary-level pattern recognition systems best suit this requirement as these systems can recognize a pattern from a binary-level