Investigation of AFM tip characterization based on multilayer gratings

Atomic force microscope(AFM) is one of the main instruments in the microscale and nanoscale measurement area. Since the AFM tip can't be infinitely sharp, the shape of the tip is included in AFM image. This is a big source of image distortion. To obtain the shape and dimensions of tip is an effective method to remove the "tip effect" and improve the accuracy of measurement images. In this study, tip characterizers with high intra-sample uniformity were fabricated by utilizing the Si/SiO₂ multilayer gratings technology, and critical dimension(CD) structures with a nominal CD of 20 nm had been fabricated to calibrate the tip. The calibration results showed that the selected AFM tip(Rectangular Front Etched Silicon Probe, RFESP) became blunt after scanning, together with the front side angle(15°) and back side angle (25°) increased to 36° and 45°, respectively. Therefore, the tip characterizers formed by the Si/SiO₂ multilayer CD structures can be used to quickly obtain the side angle information, which is an effective method to complete the fast check and estimations of tip shapes during the AFM scanning. The investigation of AFM tip characterization based on multilayer gratings are meaningful for the promotion of accuracy in AFM measurement images.