The Location Detection And Error Analysis Of IC Chip Solder Based On Machine Vision

IC (Integrated Circuit) industry is an important indicator of measuring a country’s comprehensive strength. It is an significant support for changing the development model and enhancing the level of industrial development. The packaging technology of integrated circuit is a very essential foundation for changing the IC chips into microelectronic devices with practical value. Therefore, the research on the wire bonding technology which is frequently used in IC packaging technology carries great importance.Machine visual technology is playing an increasingly important role in the process of automatic production due to its advantages:non-contract, high efficiency and high precision. Meanwhile, in order to meet the demands for high integration, high accuracy and high refining, which are proposed by the wire bonding technology, this present thesis introduces machine visual technology into the study of wire bonding technology. Besides, the present study focuses on the visual locating system which is related to the wire bonding technology. It also studies the ways of establishing experimental platform according to the requirements put forward by the wire bonding technology. And this thesis pays close attention to the design of software-positioning algorithm, which needs the connection of machine visual technology and image processing technology. The main research contents of this thesis are organized as follows:Firstly, conducting overall design of the wire bonding visual positioning system, including the design of experimental platform and the design of software algorithms.experimental platform design contains the hardware selection and the design of the optical imaging system, etc.; software algorithm design includes corner detection, correction calculation and so on. And this paper analyzes the errors occurring in the entire positioning system, including:the lens distortion in the process of image acquisition, chip manufacturing, chip errors and errors of software algorithm. Through analyzing the visible errors mentioned above, the author gives an accurate assessment of the merits and demerits of the entire visual localization algorithm.Secondly, taking the experimental platform of the system into consideration and designing the assessment algorithm which is aimed at analyzing the errors occurring in camera lens to obtain images. This kind of algorithm adopts traditional camera calibration algorithm and studies the arrayed target type featuring graphic dots. The acquired single frame images can be used to calculate the internal and external parameters of the camera. At the same time, the errors of lens distortion in the image acquisition process can be calculated. All the statistics mentioned above provide reference to researchers to decide whether to carry out the correction of the distorted images or not. The simulation experiment results verify that the algorithm produces high accuracy and efficiency and that the algorithm has a strong universal applicability.Finally, in order to match the characters of bare chips and base images, this paper comes up with the design of positioning calculation system, which is based on the matlab software platform. This new design makes the errors occurring in the process of wire bonding by patches and chips easy to be corrected timely. By analyzing the features of bare chips and base images, the present study adopts the calculation system based on geometric center to calculate the virtual corner of bare chips. Next, the actual position coordinates can be known, which makes preparations for obtaining the correction statistics of displacement and angle of both bear chips and base images. When the research result achieves the feedback on bone head, the highly precised and highly efficient bonding will be gained. Simulation experiments show that this algorithm can achieve real-time correction of bonding and the base position deviation. In addition, the positioning accuracy meets the requirements of the wire bonding process.In summary, this thesis conducts further study on the wire bonding visual locating system. And all the algorithms designed go through simulation experiments. The results show that the proposed algorithm carries high detection accuracy and recognition rate, which presents a relatively good result. The research results obtained in this paper carries both theoretical value and practical value in the following three aspects:machine visual detection technology, correction technology of image distortion and detection technology of virtual corner.