随着集成电路特征尺寸的不断减小, I/O引脚数日益增加。对于高密度封装, 尤其是2.5D/3D封装中, 电子元件和基底快速而准确的对准十分关键。利用高性能CCD搭建了一套精密的光学视觉对准系统, 并采用Hough变换算法对芯片和基底进行对准试验。采集的图像经过去噪预处理后采用形态学边缘检测方法提取对齐标记, 并通过Hough变换得到4组平行直线, 然后计算基底的位移和旋转角度并完成对准。使用Matlab编程配准, 程序运行时间约为 4.2 s, 旋转参数的误差小于1.2°, x和y轴的平移误差均小于1 pixel。试验结果表明基于Hough变换算法的光学视觉对准系统可以快速而精确地实现芯片和基底对准, 满足IC封装需求。

As the integrated circuit(IC) characteristic size continues to decrease, the number of I/O pins is increasing. For high-density packaging, especially in 2.5D/3D packages, fast and accurate alignment of electronic components and substrates is critical. A precise optical vision alignment system was set up by using the high precision charge coupled device (CCD) , and the Hough transform algorithm was utilized to calibrate the chip and the substrate. The image captured was preprocessed to remove the noise, and the alignment marks were extracted by using morphological edge detection method, and 4 sets of parallel straight lines were obtained by Hough transform. Finally, the displacement and the rotation angle of the substrate were calculated and the alignment was completed. The running time of the Matlab program is about 4.2 s, the rotation parameter error is less than 1.2 °,x and y axis translation errors are less than 1 pixel. The experimental results demonstrate that the optical visual alignment system based on the Hough transform algorithm can realize chip and substrate alignment quickly and accurately to meet the IC packaging requirements.