The State Administration for Market Regulation has recently officially approved two ultra-precision nano-gratings jointly developed by Tongji University, the National Institute of Metrology of China (NIM) and the Shanghai Institute of Applied Physics, Chinese Academy of Sciences as the first class of National Certified Reference Materials. The two materials filled the gap of certified grating reference materials below 300nm in China and provided reference materials support for realizing China’s self-traceability in nanometer measurement.
The Gradation Certificate of the National Certified Reference Material (Chrome Nano-grating)
The Gradation Certificate of the National Certified Reference Material (Silicon Nano-grating)
Academician LI Tongbao’s team, relying on the Key Laboratory of Advanced Microstructure Materials of the Ministry of Education at Tongji’s School of Physical Science and Engineering, has been the first in China to develop ultra-precision gratings traceable to natural constants by atomic lithography since 2002. The chromium gratings at 212.8nm spacing have uniformity across scales (from 100nm to mm). At the same time, the research team proposed a new ultra-precision grating frequency doubling method based on “atomic lithography + soft X-ray interference lithography” for the first time in this field. It jointly developed a silicon grating at 106.4nm spacing in collaboration with Researcher TAI Renzhong’s team of Shanghai Synchrotron Radiation Facility (SSRF). The above two ultra-precision gratings have undergone a year-long uniformity test, stability test and metrological calibration traceable to the definition of “meter” by the NIM’s nano-metrology team, indicating that the critical parameters of the gratings are stable and reliable. Their quality has reached the practical level, which can be used for the calibration and precision displacement measurement of various nano-metrology instruments, providing essential support for the development of semiconductors, optoelectronics, and artificial intelligence. At present, the project team is carrying out research work on measurement and processing instrument calibration, precision displacement measurement, and natural constant comparison based on self-traceable gratings, and promoting demonstration applications in optoelectronic and microelectronic industries.
Written by CHEN Jie
Photographed by DENG Xiao
https://news.tongji.edu.cn/info/1003/77268.htm?ivk_sa=1023197a
