晶圆外延层电阻率无损测试仪方案设计 电子科学技术专业

晶圆外延层电阻率无损测试仪方案设计摘 要电阻率作为半导体材料中一个很重要的性能指标,通过对它的测量可以得到材料的掺杂浓度等众多重要的信息,所以其测量过程很重要。为了适应集成电路的快速发展,半导体材料需要更高的检测要求，仅仅要求测量结果准确已经不能满足人们的需求了，还要保证检测过程对被测物体无损坏,这就迫切需要可靠性好、测量精度高的无损测试方案。涡流法检测作为一种非接触式的电阻率测量方法，因为其具有与被检测工件没有任何物理性质的接触、不需要耦合介质，易于在高速生产线上使用的优点，所以本文将主要介绍一种基于涡流原理的电阻率无损测试仪的设计方法。本设计利用电磁场与电路相关理论，合理选用了涡流阻抗分析法对晶圆外延层电阻率的无损测试过程进行分析。涡流检测仪检测系统的设计主要由三部分组成，分别是恒定交变电流源、微弱信号采集处理电路和数据处理显示电路。设计过程中，首先采用具有稳幅结构的文氏桥式振荡电路作为激励信号发生器，设计了 U-I 转换电路使激励信号具有恒流特性，同时采用锁相放大器来对微弱信号进行采集和处理，最后以 AT89S52 单片机作为数据处理系统并利用 LCD12864 进行数据显示。关键词：电阻率 无损测试 涡流Design of the Resistivity Nondestructive Tester for Wafer Epitaxial LayerAbstract: As a very important performance index of semiconductor materials, the resistivity can be measured to obtain many important information such as the doping concentration of materials, so its measuring process is very important. In order to adapt to the rapid development of integrated circuits, semiconductor materials need higher testing requirements. It is no longer possible to only require accurate measurement results to meet people's needs, but also to ensure that the testing process has no damage to the object under the test. Therefore, a non-destructive testing scheme with good reliability and high measurement accuracy is urgently needed. As a non-contact resistivity measurement method, eddy current testing method has the advantages of no physical contact with the workp...