大台阶高度测量的外差共焦方法  

Method of Heterodyne Confocal Microscopy Measuring Big Step Height

作　　者：闫聚群[1] 柳忠尧[1] 林德教[1] 张蕊[1] 殷纯永[1] 徐毅[2] 许婕[2] 

机构地区：[1]清华大学精密仪器与机械学系精密测试技术与仪器国家重点实验室,北京100084 [2]中国计量科学研究院,北京100013

出　　处：《中国激光》2005年第3期389-393,共5页Chinese Journal of Lasers

基　　金：国家自然科学基金(50027002);清华大学博士生创新基金联合资助项目.

摘　　要：台阶高度是微电子产品的一个重要性能参数.基于双频激光干涉共焦显微系统(DICM)提出了一种微电子掩膜板台阶高度测量的扫描方法,在共焦显微扫描样品表面,当光强达到最大值时,将采样外差干涉的相位作为精确对准的判据.该扫描方法集中融合了外差干涉测量和共焦显微测量的优点,同时实现了高分辨率与较大量程的测量,该系统测量台阶高度的范围取决于Z向位移扫描仪PI Foc的扫描范围,可达数十甚至近百微米.实验结果表明该系统在普通恒温的实验条件下1 h内的漂移不超过5 nm,该系统已经用于20μm高台阶的测量,对准分辨率为0 1 nm,实验结果与台阶高度实际值有很好的一致性.Step height is an important parameter of micro-electronic mask. A new approach named dual-frequency interferometric confocal microscope (DICM) is proposed which combines scanning confocal microscopy with heterodyne interferometry. The phase of heterodyne interferometry is recorded as an aim criteria when optical intensity of confocal microscopy is in maximum. This method implements high resolution (0.1 nm) and relatively large measurement range (> 15 μm) simultaneously. Also the step height measurement range depending on the range of Z axis PI-Foc scanner which theoretically can be extended to 100 μm. The results show that in ordinary laboratory condition, with temperature controlled, the drift of phase measurement is about 5 nm in an hour. The 20 μm step height has been successfully measured and the results agree with the actual value.

关 键 词：测量与计量 共焦显微术 外差干涉 相位测量 台阶 

分 类 号：TB92[一般工业技术—计量学] TN247[机械工程—测试计量技术及仪器]