Development of a metrological atomic force microscope with a tip-tilting mechanism for 3D nanometrology
Development of a metrological atomic force microscope with a tip-tilting mechanism for 3D nanometrology
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DOI：
10.1088/1361-6501/aabe1a
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发表时间：
2018-07-01
影响因子：
2.4
通讯作者：
Gonda, Satoshi
中科院分区：
文献类型：
--
作者：
Kizu, Ryosuke;Misumi, Ichiko;Gonda, Satoshi
具有尖端倾斜机构 (tilting-mAFM) 的计量原子力显微镜的开发旨在扩展 3D 纳米计量学的能力，特别是用于垂直侧壁表面的高分辨率形貌测量以及纳米器件线宽的可追踪测量。在倾斜mAFM中，探针尖端从垂直倾斜到最大16度，使得探针尖端可以接触并追踪纳米级结构的垂直侧壁；传统原子力显微镜的探头由于其有限的锥角而无法到达垂直表面。通过使用高分辨率激光干涉测量法在三个轴上监测探头位移，该测量可追溯到 SI 长度单位。具有平行弹簧结构的中心对称 3D 扫描仪可实现极低轴间串扰的探头扫描。还开发并应用了扫描垂直侧壁的独特技术。实验结果表明扫描轮廓和侧壁角度测量具有高重复性。此外，还演示了线条图案的 3D 测量，并且来自两个侧壁的数据成功地以亚纳米精度缝合在一起。最后，得到了线路图案的临界尺寸。
A metrological atomic force microscope with a tip-tilting mechanism (tilting-mAFM) has been developed to expand the capabilities of 3D nanometrology, particularly for high-resolution topography measurements at the surfaces of vertical sidewalls and for traceable measurements of nanodevice linewidth. In the tilting-mAFM, the probe tip is tilted from vertical to 16 degrees at maximum such that the probe tip can touch and trace the vertical sidewall of a nanometer-scale structure; the probe of a conventional atomic force microscope cannot reach the vertical surface because of its finite cone angle. Probe displacement is monitored in three axes by using high-resolution laser interferometry, which is traceable to the SI unit of length. A central-symmetric 3D scanner with a parallel spring structure allows probe scanning with extremely low interaxial crosstalk. A unique technique for scanning vertical sidewalls was also developed and applied. The experimental results indicated high repeatability in the scanned profiles and sidewall angle measurements. Moreover, the 3D measurement of a line pattern was demonstrated, and the data from both sidewalls were successfully stitched together with subnanometer accuracy. Finally, the critical dimension of the line pattern was obtained.