Surface Imaging Technique by an Optically Trapped Microsphere in Air Condition
Surface Imaging Technique by an Optically Trapped Microsphere in Air Condition
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DOI：
10.1007/s41871-018-0004-0
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发表时间：
2018-01
影响因子：
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通讯作者：
M. Michihata;Jonggang Kim;S. Takahashi;K. Takamasu;Y. Mizutani;Y. Takaya
中科院分区：
文献类型：
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作者：
M. Michihata;Jonggang Kim;S. Takahashi;K. Takamasu;Y. Mizutani;Y. Takaya
最近制造技术的进步使得在微结构上形成纳米级的表面图案化成为可能，这需要在同一坐标系中进行多尺度测量来确定其几何尺寸和表面纹理。此前，我们已经开发了一种带有激光捕获微探头的微坐标测量机，该探头使用光学捕获微球作为表面检测传感器。本文提出了一种利用光学捕获微球作为微透镜的表面成像技术，即将表面成像系统集成到坐标测量系统中。将直径为8μm的光学捕获微球带到接近测量表面的位置，以对其下面的表面进行成像。由于微球和表面之间存在一个未知的间隙，成像系统的焦平面必须通过所研制的成像透镜系统调整到被测表面。利用基于微球的成像系统，成功地对间距为417 nm、深度为50 nm的亚微米周期结构的光学衍射栅进行了成像，并对其缺陷进行了检测。从而验证了基于光学捕获微球的多尺度评价系统成像系统的研制是可以完成的。
Recent advancement of fabrication technologies enables nanoscale surface patterning on microstructures, which requires multi-scale measurements for the determination of their geometric dimensions and surface texture in the same coordinate system. Previously, we have developed a micro-coordinate measuring machine with a laser-trapped microprobe that uses an optically trapped microsphere as a surface detecting sensor. In this paper, we propose a surface imaging technique using the optically trapped microsphere as a micro-lens, i.e., the surface imaging system is integrated into the coordinate measuring system. The optically trapped microsphere with a diameter of 8 μm was brought close to a measured surface to image the surface underneath it. Because there is an unknown gap between the microsphere and surface, the focal plane of the imaging system had to be adjusted to the measured surface by the developed imaging lens system. With the microsphere-based imaging system, an optical diffractive grating of sub-micrometer periodic structure with 417 nm pitch and 50 nm depth was successfully imaged and the defect on the grating was detected. Thus, we verified that development of an imaging system based on the optically trapped microsphere for multi-scale evaluation systems can be accomplished.