基于白光相移干涉术的微结构几何尺寸表征

将Carré等步长相移法与白光垂直扫描相结合形成了一种白光等步长相移算法,该方法快速、准确、非接触,垂直分辨力可达亚纳米级.测量系统集成了Mirau显微干涉物镜,并通过高精度压电陶瓷纳米定位器带动物镜进行垂直扫描.分析了Carré法应用于白光干涉信号的相位提取的精度,对不同扫描步距以及不同信噪比情况下的测量进行了计算机仿真,确定了测量参数.结合重心法将相位计算的数据范围直接定位于干涉信号的零级条纹,从而省去了相位解包裹过程.通过对微谐振器和标准台阶的测量说明了该方法的有效性,并使用白光相移干涉、白光垂直扫描和单色光相移干涉对44 nm标准台阶进行了测量,并对测量结果进行了比较.

MEMS Geometric Parameters Measurement Based on White Light Phase Shifting Interferometry

A white light phase shifting method for interferometry with sub-nanometer resolution based on the combination of Carré phase shifting and white light vertical scanning was proposed,which can conduct the measurement fast,accurately and non-contact.The system was composed of a Mirau driven by a high precision piezoelectric transducer.The phase extraction with Carré phase shifting method on white light interferogram was firstly analyzed and several numerical simulations under various scanning step lengths and signal to noise ratios were followed to determine the parameters of the measurement.Then,the centre of mass gravity method was employed to locate the phase computation directly on the zero-order fringe so that the phase unwrapping was no longer needed.The performance of the new method was illustrated through the measurements of the micro-resonator and a 44 nm standard step height,and the comparison of the results of the 44 nm standard step height measurement by white light phase shifting inter-ferometry,white light vertical scanning and phase shifting interferometry was also made.