基于小波包络提取法的白光干涉测量系统

White Light Interference Measuring System Based on the Wavelet Envelope Extraction Method

为实现对微纳尺寸器件的非接触、无损伤的场式测量,基于纳米测量机(NMM)搭建了白光干涉测头。对测量系统的横向、纵向测量范围及分辨率进行了研究。测量系统集成了Michelson显微干涉物镜,并通过NMM的高精度定位平台带动被测样品进行垂直扫描,使用CCD相机采集干涉图像,小波包络提取法提取干涉信号包络,定位相干峰位置以获取被测样品表面形貌。实验分别测试了44 nm的纳米级台阶及10μm的微米级台阶,同时测试墨盒薄膜上数字‘232’以验证系统测量微纳器件的能力。结果表明搭建的白光干涉系统结合小波包络提取法能够用于微纳尺寸器件高精度、快速的测量。

Based on the nano measuring machine（NMM）,the white light interference sensor（WLIS）was constructed to realize the non-contact and nondestructive field measurement of micro/nano scale devices.Its measurement range and resolution in vertical and lateral directions were investigated.The measuring system was composed of a Michelson microscope interference objective and the vertical scanning of the tested sample was driven by the high precision positioning platform of the NMM.The interference images were acquired by the charge coupled device（CCD）,and the interference signal envelope was extracted by the wavelet envelope extraction method,then the coherence-peak position was determined and the surface morphology of the tested sample was obtained.The nano scale step of 44 nm and micro scale step of 10μm were measured,respectively.And the number′232′on the ink box was measured to verify the measuring ability of the micro/nano scale complex device.The results show that high precision and fast measurement of the micro/nano scale device can be realized with the wavelet envelope extraction method through the white light interference system.