白光干涉法微观台阶测量

Micro Stage Measurement Based on White Light Interference

摘要:

在微纳器件测试与计量标定领域,很多问题都涉及到对微观台阶的高精度测量。白光干涉垂直扫描法具有非接触、精度高、速度快等优点,基于此搭建了白光干涉微观检测系统。利用相移干涉理论,解算出被测微观台阶的空间相对高度信息。通过中值滤波加间隔差分取极值的方法,有效识别出台阶的左右两个边缘,减小了脉冲等噪声带来的干扰。以C#语言编写了WPF形式的检测软件系统,并对标准的微观台阶进行了多次实验。实验结果表明,该方案测量的平均偏差稳定在2nm以内,重复性精度优于0.5%。

Abstract:

In the measurement and calibration of micro-nano devices, high accuracy measurement of micro stage is of great importance. White light interference method of vertical scanning presents the characteristics of noncontact, high accuracy and high speed, thus a white light interference micro measuring system was built. Based on phase shift interference theory, the relative space height information of the micro stage was demodulated. By means of median filtering and interval difference, the left and right edges of steps were identified effectively, and the interference caused by noise was reduced. The testing software system in the form of WPF was written in C# language, and many experiments were carried out on standard microscopic steps. Experimental results show that the average deviation of this scheme is stable within 2nm, and the repeatability accuracy is better than 0.5%.