标题: | 线上BGA影像检测之探讨与改进 The Investigation and Improvement on the On-Line Images Inspection of BGA |
作者: | 陈佳良 Chia-Liang Chen 李安谦 An-Chen Lee 机械工程学系 |
关键字: | BGA;影像检测;BGA |
公开日期: | 2000 |
摘要: | 本论文是针对改善一套BGA的影像检测系统所进行的研究。内容先 解说BGA锡球在基板上植球状况的缺陷和分类情况,再介绍检测缺陷所使用的规则。对于检测流程所需的各个影像处理环节,则经由分析多种方法的应用结果,比较出最好的采行方式,找出了最适合的二值化门槛值以及精度较佳的次像素法,此两种手法有助于改善原系统的性能。为了提升系统的检测速度;同时以最小误差圆法逼近锡球外形,并引入真圆度的定义,防止有形状缺陷的锡球通过检测。为了健全系统的功能,也针对检测取像时BGA基板与CCD之间的角度偏位及补正方式进行了相关的探讨和研究;并进一步提出具体的改善。此外,本文对于系统的校正也有详细的介绍,期望能对BGA检测的实务有所助益。 最后的实验结果显示,改进后的系统,除了可对机械定位不良的BGA基板进行正常的检测外,在尺寸量测的稳定度上也有所提升。在检测336颗直径为0.63mm的BGA产品时,全部花费时间只要0.3秒,大约是原来系统所需时间的四分之一而已。大幅提升检测的效率。 The purpose of this thesis is to improve a preliminary developed BGA(Ball Grid Arrays) inspection system. The contents first provide an overview on all kinds of flaws of the BGA devices, then introduce new rules for defect detection. By comparing results of different methods for each image processing steps of inspection procedure, we try to look for more suitable ways. We find out that the most suitable threshold value for image segmentation and a better sub-pixel edge-detect operator would be helpful to upgrade the original system. To improve inspection efficiency, we use least-square error circle fitting method to approximate the shape of solder balls. Moreover, we introduce the definition of circularity to prevent defective solder balls from passing the inspection. To improve the functionality of the original inspection system, we provide an improvement proposal for the compensation method of the moving angle deviation of between the BGA substrate and the CCD camera during the image capture procedure. Finally, the contents have complete introduction for system calibration, which can aid the implementation of the BGA inspection. The final outcomes show that the upgraded system not only successfully inspects BGA devices with no correct position, but also has more stability in size measurements. It takes the upgraded system only 0.3 seconds to complete inspection of a BGA device with 336 solder balls of 0.63mm diameter. This is 4 times faster than the original system. |
URI: | http://140.113.39.130/cdrfb3/record/nctu/#NT890489068 http://hdl.handle.net/11536/67567 |
显示于类别: | Thesis |