【作者】 李洋；

【导师】 杨华中； 陈国伟；

【作者基本信息】 清华大学 ， 电子与通信工程， 2009， 硕士

【摘要】 随着大规模集成电路技术的发展,电路板的复杂性大大增加,传统的物理探针测试方法遇到严重挑战,边界扫描技术正是为了解决这一问题而提出的。本文在充分理解边界扫描测试运行机制的基础上,研究如何在电路板测试中应用边界扫描技术。本文采用ASSET公司的边界扫描测试开发平台SCANWORKS,为一些电路板开发了边界扫描测试程序。并通过开发过程中的学习和实践,总结了一些基于边界扫描技术的可测性设计方法,包括设计边界扫描链路的方法,提高测试覆盖率的方法,加快运行速度的方法等。在设计电路板时,这些可测性设计方法有助于发挥边界扫描技术的优势,提高测试方案的效率。本论文还重点进行了互连测试算法研究。互连测试是边界扫描技术最主要的应用,存在大量经典的算法。传统算法大都采用单一的故障模型。本论文采用了多种故障可能同时存在的复杂故障模型,以此为基础,结合边界扫描技术的特点,对传统的自适应算法进行了优化,提出了基于反向测试的自适应算法。在新的算法中,对自适应算法中初步测试算法的选择做出了扩展,证明了Wagner算法和W. T. Cheng第三算法都是独立性算法,可以用于混合故障的初步测试;并且利用最大诊断的概念,采取反向测试和正向测试结合的方法,在完备诊断之前排除已经达到最大诊断的线网,从而缩小完备诊断的测试规模,用更少的测试向量达到对混合故障的最大诊断。减少的向量数量取决于电路网络的规模和故障的分布情况,本文给出了相应的计算公式。更多还原

【Abstract】 The complexity of Printed Circuit Board (PCB) is on the prompt increase because of the great improvement of IC technology; as a result, the traditional circuit test methods which use physical probe can not meet the requirement. Boundary Scan Technology is developed to resolve the problem. This paper studies the PCB manufacturing test methodology based on Boundary Scan, including test action development and interconnects test algorithm optimization.Test platform is based on Boundary Scan tool of ASSET Company. Test code for 3 different boards are developed and verified, which include typical boundary scan test process such as scan chain integrity test and interconnects test. This paper also summarizes a few Design For Test (DFT) guidelines with the knowledge acquired from the test development. These DFT guidelines can be used as reference while designing boundary scan circuit, which are useful to improve test coverage and make the PCB test flexible.The board interconnects test methodology based on Boundary Scan is investigated in this paper. Traditional interconnects test algorithms assume that one net can only have one fault. A new complicated defect model has been proposed which assumes multiple defects exist on one net. 2 new adaptive algorithms which have multi-steps have been proposed. The vector generation algorithm for each step is optimized and reverse test methodology is introduced according to Boundary Scan principles. These 2 algorithms can reach maximum diagnosis with less test vectors. The quantity of the reduced vectors is determined by the nets size and defects distributing. An equation about it is provided in this paper.更多还原