关键词: 计量模型, 纳米计量, 算法, 线宽, 原子力显微镜, Cocks-Ashby模型, 多轴蠕变, 粘塑性

Abstract: Nano-scale linewidth measurements are widely performed in semiconductor manufacturing, data storage industry and micro-mechanical engineering. With the development of manufacturing technology in recent years, the sizes of linewidths are steadily shrinking and have been in the range of hundreds of nanometers. As a result, it is difficult to achieve accurate measurement results for nano-scale linewidth, because of the limitation of manufacturing technology and the influence of measuring instrument. In order to reduce the method divergences caused by different measurement methods and instruments for an accurate determination of nano-scale linewidth parameters, a metrological model and algorithm for linewidth measurements are established based on AFM measurements. The linewidth profile is divided into 5 parts with 19 sections and 20 key points and 6 accessorial points. Each section is fitted by a least squares straight line. According to the algorithm, bT and bTF, bM and bMF, bB and bBF represent the widths at the top, the middle and the bottom of the linewidth profile before and after the least squares fitting, respectively. AL and AR represent the left and right sidewall angles, and the h represents the step height of the linewidth profile. A NIST nano-scale linewidth standard developed at NIST’s Electronics and Electrical Engineering Laboratory (EEEL) was measured using a commercial AFM with ultrasharp tips. The measured linewidth profiles are used for analyses using our model, algorithm and software. The results show that the model developed addresses the need of nano-scale linewidth metrology.

Key words: Algorithm, Atomic force micros, Linewidth, Metrological model, Nano-metrology, Cocks-Ashby model, Multiaxial creep, Viscoplasticity