Improvement of spatial resolution by tilt correction in near-field scanning microwave microscopy

Abstract

The limitation of mechanical manufacturing will result in a small tilt angle of the sample stage in the horizontal direction, which decreases the spatial resolution of imaging in near-field scanning microwave microscopy (NSMM). In this paper, we focus on the tilt correction and improve the spatial resolution of the NSMM image. The results of electromagnetic simulation and line scan measurement demonstrate the critical parameters affecting the sensitivity of NSMM, such as the length of the probe extending out of the cavity, the tip–sample distance, and the tip apex size. The tilt images can rotate successfully to the horizontal plane with the tilt correction methods, and the local average and re-interpolation are applied to denoise the images. Experimental NSMM images of copper thin film grid, coin texture, lithography mask, and leaf vein are obtained. The images before and after correction verify the improvement of the spatial resolution with all the above methods.

Application of Near-Field Scanning Microwave Microscopy in Liquid Environment

“…The central resonate frequency with the specimen compared with its no-load state. The frequency variation can help adjust the tip-sample distance to an appropriate distance [30], and it has potential application in other soft materials like biological cells [33]. Each concave in these figures represents the samples of specific molarities as solutions of different molarities have different electromagnetic parameters.…”

“…Compared with other types of resonators like planar resonators [31,32], our homemade λ/4 coaxial cylindrical resonator together with x-y-z motor stage shows the ability to obtain threedimensional images of electromagnetic properties of the specimen with higher resolution. Its spatial resolution can achieve 2 µm [30]. Through the lines, the resonator is connected to a vector network analyzer (VNA, Agilent Tech- -nologies E5062A).…”

Developments of Interfacial Measurement Using Cavity Scanning Microwave Microscopy

“…Zhang et al [ 8 ] reported a method that can correct the skewing and denoising of SMM images, significantly improving the spatial resolution of the images. They detected and obtained parametric images of f r , S 11 , and Q of the veins of leaves, as illustrated in Figure 16 .…”

“… An enhanced grid contour image and f r parameter image of a copper film after tilt correction [ 8 ]. …”

“…Over the past decade, one of the most significant advances in the field of microwave testing has been the emergence of scanning microwave microscopy [1][2][3][4][5][6][7][8][9]. There are two main types of scanning microwave microscope, categorized according to the source of the microwave signals at the scanning tip, with one type using a microwave resonator coupled to the tip of the probe using a small aperture and the other using a coaxial transmission line directly attached the tip of the atomic force microscopy (AFM) cantilever.…”