基于DR/ICT的BGA封装器件内部缺陷检测技术

In recent years, BGA packages are heavily utilized in the printed circuit board productions due to the increasing demand for high-density surface mount devices and they enable surface-mount production easier to complete. Since BGA solder joints are hidden in the bottom of chips, it is not possible to detect internal defects by direct observations. In order to address this problem, the BGA internal defect detection technique based on digital radiography and industrial CT was mainly studied in this project in two respects. One is to study the level-set based active contour model and its improved algorithms according to characteristics of the ray images of BGA internal defects and then to do correct image segmentation for the progressive image with which the original image can be accurately described and all of these finally form an efficient, stable image segmentation model. Another one is to study a sort of X-ray scanning with oblique incidence for positioning BGA internal defects, which can be applied in detecting internal defects of plate component to solve the problem of the spatial orientation of internal defects. This project studies positioning, feature extraction and recognition of BGA internal defects in line with their characteristics. The project is to break the blockade of foreign technology and has important theoretical significance and practical value.

近年来，由于对高密度表面组装器件的需求不断增加，BGA 封装方式被大量地应用在印刷电路板生产当中，它们使表面封装的生产更容易完成。由于 BGA的焊点隐藏在芯片的底部，所以无法通过直接观察的方式对其内部缺陷进行检测。针对该问题，本项目主要研究基于数字射线成像和工业CT的BGA内部缺陷检测技术。针对BGA内部焊点缺陷射线图像的特点，研究基于水平集方法的活动轮廓模型及其改进算法，对灰度渐进图像能够正确分割，可精确地描述原图像，形成一种高效、稳定的图像分割模型。针对BGA内部缺陷空间定位的要求，研究一种射线斜入射扫描方式的重建算法，该方法可应用到薄板构件的内部缺陷的检测，解决了薄板构件内部缺陷空间定位的难题。根据BGA内部缺陷的特点，研究缺陷的定位、特征提取与识别方法。该项目的研究可打破国外相关技术的封锁，具有重要的理论意义和实用价值。

随着电子工业的快速发展，BGA封装方式的应用日益广泛。针对BGA封装方式具有隐藏性高、焊点缺陷不易检测等特点，本课题基于DR/ICT成像，对BGA封装器件内部缺陷检测的相关技术进行了研究。首先，基于偏微分方程、非局部均值滤波、模糊理论等研究了自适应图像降噪算法，基于形态学、模糊理论研究了图像增强方法。在此基础上，针对印刷电路板的特点，研究了斜入射分层重建算法及其他统计迭代类重建算法。接下来，对分割算法进行了研究。最后，深入研究了特征提取与缺陷识别类算法。实验结果表明，算法性能良好。在论文发表、人才培养、学术交流、专利申请等方面取得了一系列研究成果。.相关技术的研究，对于提高我国BGA封装器件内部缺陷自动检测的水平有积极的促进意义，为相关装备的研制提供了有力的理论支撑。