Design and calibration of a nano dimensional standard

Abstract

A nano dimensional standard named SIMT100 was designed and fabricated. The standard consists of a tracking area, a step height area, a 1D grating area, and a 2D grating area. All the structures were fabricated with a height of 100 nm in a 3 mm × 3 mm silicon substrate. To calibrate the standard, a white light interference microscope was constructed and integrated to the nano measuring machine (NMM). The height of a 10 μm width step measured by white light interference (WLI) microscope was 100.2 nm with a standard deviation of 0.41 nm. Due to low lateral resolution of the optical microscope, a metrological atomic force microscope (AFM) was used to measure the 1D and 2D gratings. The period length of the 1D grating evaluated by using the fast Fourier transform (FFT) method was 2999.7 nm with a standard deviation of 0.36 nm. The FFT method was also expended for evaluation of the 2D grating. The calibrated value of 2D grating along the x- and y-axis were 3001.2 and 3000.7 nm with standard deviations of 0.73 and 0.64 nm, respectively. All the measurement results are traceable because the data was recorded by three stabilized laser interferometers embedded in the NMM.