| Ultrasonic aluminum wire bonder and ultrasonic gold wire bonder are mainly applied to joint the chip pad with the lead-frame in the later process of semiconductor producing. This project aims at the achieving automatic reconstruction of these manual equipments using in the small and medium-sized enterprises, which is funded by Department of Education of Guangdong Province.The automatic equipment after reconstructing adopts the machine vision automatic recognition technology. If the same type of chips needs to be jointed, the workers just need to inspect and identify once, and then the system will run automatically, no need interfere any more. The rest task for workers is to convey the chips. So one worker can operate several automatic bonders, and naturally the productivity improves considerably. This automatic bonder will be welcomed by the small and medium-sized enterprises in the future. In order to achieve the target, our project is to complete this automatic reconstruction. This dissertation introduces and summarizes the main parts of this project.The primary research is as follows:(1) The reconstruction proposal is brought forward, and the hardware system and software system of automatic bonder are specifically designed. At the same time, two schemes that can be used are analyzed with emphasis, that is, the hardware image processing system and the software image processing system. Compared with these two schemes, we decide to adopt the latter method combining with the actual condition.(2) The quality of image declines a bit because of the noise pollution. To counter this problem, we determine to smooth the image firstly, and then enhance the image. The course of pre-processing is as follow: first, the image is smoothed by the median filter. The image is filtered the disturbance of noise while the edge is retained. Then the image is enhanced by gray histogram trimming and improved its contrast, neglecting some unsteady details. Consequently the pre-processing paves the way forlatter image matching.(3) Some commonly used fast image matching algorithm base on gray matching are discussed, including FFT algorithm, Multitude Sorting Relational algorithm, Sequential Similarity Detection algorithm, Multi-resolution Pagoda Structure algorithm and Genetic algorithm. In this project, precision and velocity is highly demand. By comparison, Sequential Similarity Detection algorithm bears the characteristics of speedy calculation, accurate orientation and anti-jamming, which is fit for the high requirement in industry. In this project, we improve the arithmetic of SSDA and divide the matching process into two steps: the first one is the rough matching and the second one is the precise matching. This greatly improves the precision and pace in orientation.(4) The automatic jointing machine is to locate bonding point preciously, which means locating bonding point with the place of every couple of bonding points in a precise way. In detail, the places means coordinates of the bonding points. In the condition of the same outer environment and type of chips and the place of camera remain unaltered, the distance between bonding point and chip center is approximately the same. If the chips are mounted on frame manually, there must be the rotation and excursion of chips existing , so there will be some deviations in the distance.In order to solve this problem, we decide to apply analogy study. The course is as follow: First the distance between welding points of chip center is measured by manual work. And then the position of chip is confirmed by template matching. Last, through modifying, the precise coordinates is calculated. This method of locating bonding point is precious and quick.The productions of this project improve the manufacturing status of our nation's small and medium-sized enterprises. It's of significant for raising the large economic and society benefit. The outlook of industrialization is optimistic. Besides that, this research points out a new approach for further developmen... |
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