接触孔关键尺寸测量研究与工序能力提高

Research on Contact Critical Dimension Measurement and Process Capability Improvement

在集成电路制造业,对关键层次的CD(Critical Dimension,关键尺寸)测量是控制质量的重要手段。广泛采用统计过程控制SPC(Statistical Process Control)系统来控制工艺稳定性。介绍了扫描电镜的基本工作原理和常见问题,通过增加dummy site及选择测量位置的方法降低充电效应,以提高测量图形质量和CD测量精度。利用方差分析优化测量设备参数,并利用回归分析的方法对不同测量机台进行匹配,最终达到R^2=0.99,实现了不同测试机台的匹配,提高了孔层次的CPK(Process capacity index,工序能力指数)。这种工程技术和统计学结合的匹配优化方法还可以进一步扩展到其他相同属性不同类型的测量机台的数据匹配上。

In integrated circuit manufacturing enterprises, critical dimension measurement and statistical process control are significant for quality control and process reliability. The paper at first overviews the working principle and issues of scanning electron microscope and highlights the charging effect reduction by adding dummy site and selecting the measurement locations. Then the paper optimizes measurement equipment parameters and matches different measurement machines, thereby enhancing the CPK. The matching optimization method combining the engineering and statistics can be further extended to data matching of various measurement machines.