Zhang Weipeng, Wei Haoyun, Yang Honglei, Wu Xuejian, Li Yan
Appl Opt. 2018 Feb 10;57(5):1247-1253. doi: 10.1364/AO.57.001247.
A precise 3D surface measurement method for large stepped structures without height ambiguity is proposed based on optical-frequency-comb-referenced frequency-sweeping interferometry and Fourier-transformed fractional phase retrieval. Unlike other interferometry that depends on the absolute phase value for several certain wavelengths, this method obtains results from the phase change during frequency sweeping and thus remains free from the confined non-ambiguity range. By reference to an optical frequency comb, the relative uncertainty from the tunable laser frequency was reduced by three orders of magnitude, and the sweeping frequency range can be precisely determined. Besides, the fractional phase can be rapidly retrieved in only one step using a Fourier transform method, with advantages of high accuracy and immunity to light intensity fluctuation and mechanical vibration noise. Samples of step heights from 1 μm to 1 mm were measured, and the standard uncertainty was 45 nm. This permits applications such as quality assurance in microelectronics production and micro-electro-mechanical system (MEMS) manufacture.
基于光学频率梳参考扫频干涉测量法和傅里叶变换分数相位检索，提出了一种用于大型阶梯结构的精确三维表面测量方法，该方法无高度模糊性。与其他依赖于几个特定波长的绝对相位值的干涉测量法不同，此方法从扫频期间的相位变化获取结果，因此不受限于有限的无模糊范围。通过参考光学频率梳，可调谐激光频率的相对不确定度降低了三个数量级，并且扫频范围可以精确确定。此外，使用傅里叶变换方法仅一步即可快速检索分数相位，具有高精度以及对光强波动和机械振动噪声免疫的优点。测量了高度从1μm到1mm的台阶样品，标准不确定度为45nm。这使得该方法可应用于微电子生产和微机电系统（MEMS）制造中的质量保证等领域。
