热超声倒装键合机视觉系统的设计与实现.docxVIP

第 38卷第 1期2007年 2月中南大学学报(自然科学版)J. Cent. South Univ. (Science and Technology)Vol.38 No.1Feb. 2007热超声倒装键合机视觉系统的设计与实现李建平，邹中升，王福亮(中南大学机电工程学院，湖南长沙，410083)摘要：针对热超声倒装键合过程中对准工作的特点，确定合理的视觉自动对准方案，在对多种颜色和形状的 LED光源进行实验对比的基础上，设计环形 LED光源与单个 LED发光二极管组合的照明方式，使芯片、基板表面亮度一致且表面几何特征清晰。视觉软件以 HexSight为核心，利用创建参考点实现不同目标的识别，并对 2个 CCD摄像机的控制方案进行优化。通过分析多次识别结果对单项误差进行评估，并以实验用 1 mm×1 mm的表面有 8个凸点的芯片为例计算视觉识别系统的综合误差，结果表明此视觉识别系统满足芯片键合时对定位精度的要求。关键词：热超声倒装键合；机器视觉；HexSight视觉软件；误差分析中图分类号：TP242.6+2；TP271+.4文献标识码：A文章编号：1672-7207(2007)01?0116?06Design and realization of machine vision system inthermosonic flip-chip bonderLI Jian-ping, ZOU Zhong-sheng, WANG Fu-liang(School of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China)Abstract: According to the fact that accurate alignment is very crucial in the process of chip package, the structure ofvision alignment system in automatic thermosonic flip-chip bonder was presented. Based on experiments on various colorand style LED lights, the single-color LED illumination composed of a ring LED light and some LED lamps was adoptedto get uniform luminance within visual field. The vision software was developed based on HexSight, the method ofrecognition of different objects(chip substrate), control of two CCD cameras and key points of creating model for chipand substrate were presented. According to the recognition error of translation by experiments on scale 1 mm×1 mmchips, the composite position error of the vision system was calculated, and the result demonstrates that the precision ofthis vision alignment system satisfies the bonding process of scale 1 mm×1 mm chips with 8 bumps.Key words: thermosonic flip-chip bonding; machine vision; HexSight software; error analysis随着电子制造工艺的进步，元件的微型化，组装的高密化、高速化，微电子行业对制造设备的运动速度和精度的要求越来越高。现代电子制造设备的定位精度已达到 2~5 μm，下一代电子制造设备的定位精度将小于 1 μm[1?2]。对于这样的微米级定位精度，传统机械制造设备的粘接和装夹技术均无法实现。在现代电子制造设备中，芯片及其上的焊盘在工作台上的精包括视觉定位系统的硬件结构设计和视觉定位软件的开发。在热超声倒装键合过程中,关键环节是芯片凸点和基板焊盘的互连，其间输入/输出点定位和对准精度误差要求小于 5 μm。为此，本文作者根据热超声倒装