Being a precision measurement technology on the nanometric scale, nanometrology is a fundamental technology adopted by advanced nano-fabrication. The development of nanometrological standard substances is vital, not only to guarantee the dissemination of traceability, an elementary topic in nanometrology, but also to ensure the unity and accuracy of nano-geometric measurements. Thus far, nanotechnology is evolving towards the direction of reducing characteristic dimensions, which has forced the advanced manufacturing industry to urgently find nano-length standard substances with high accuracy and stability, including the linewidth, step height, linear scale, pitch (one-dimensional grating, 1D), and grid (two-dimensional grating, 2D). To respond to the newly emerged requirements of nodule geometric forming control and planarization for the quantity-value dissemination and traceability, based on the chromium transition frequency, the optical metrology groupfabricated a variety of self-traceable grating standard substances, such as 1D 212.8 nm, 2D 212.8 nm, and 1D 106.4 nm by atomic lithography and soft X-ray interferometry. Considering the development of silicon nano gratings by multilayer deposition technology, they also explored a self-traceable measurement method of silicon nanowires based on the lattice constant of silicon. Regarding applications, the research group has conducted studies on the real-time calibration of self-traceable grating to various types of high-precision measurement instruments, including the scanning probe microscope and scanning electron microscope. Meanwhile, other measurement instruments that are based on self-traceable grating have been developed, such as the ultra-precision displacement sensor, accelerometer, and grating pitch calibration device. Research results demonstrated that utilizing the self-traceable standard substances and the corresponding measurement methods can shorten the nanometric traceability chain during the process of using various types of high-precision instruments and machining, which provides a steady foundation for advanced nanomanufacturing and the new generation information technology.
