用计量型AFM对一维纳米基准栅的标定及不确定度估计

Calibration and Uncertainty Estimation of One-dimensional Reference Grating Using a Metrological Atomic Force Microscope

利用轻敲模式的计量型AFM对公称栅距为240nm一维基准样板进行了标定,在充分分析AFM的结构和特性、测量过程、数据处理的基础上,得到了基准栅的平均栅距估计值和扩展不确定度。通过全面的不确定度分析,估计值的扩展不确定度达到了亚纳米量级。该不确定度分析表明,对于纳米量级测量,不确定度估计不仅需要全面掌握测量仪器、测量过程中各种测量不确定因素的影响,还需要考虑和估计常规测量过程中可以忽略的二次误差的影响。

A one-dimensional reference grating with nominal pitch of 240 nm was calibrated using a tapping mode metrological AFM.Based on the analysis of the AFM structure and properties,measuring process,and data processing,the average pitch was obtained and its uncertainty was estimated.The expanded uncertainty of average pitch was in the order of sub-nano meter.According to the uncertainty analysis of this calibration,it is shown that the estimation of measuring uncertainty should be done based on the well understanding of the all factors in the measuring instrument and measuring process.Furthermore,the some secondary-order errors neglected in conventional measurement should be considered and estimated in nano measurement.