Nano Precision Noncontact Probing System Using Tungsten Ball Tip for High Aspect Ratio Structures With Horizontal Internal Dimensions Below 100 μm. - Peng Xu; Rui-Jun Li; Yi Shen; Rong-Wei Lin; Pan Yao; Zhenying Cheng; Liansheng Zhang; Qiang-Xian Huang; Fang Cheng (IEEE Trans. Instrum. Meas., 2024)