FIG. 1. Image of 20 μm standard grid sample in 20X, 50X magnification. (a) Image in 20X. (b) Image in 50X.
FIG. 2. Intensity profile of standard grid sample’s edge in 20X, 50X magnification.
FIG. 3. Intensity distribution of 50X magnified image in three dimensions.
FIG. 4. Intensity and derivative of intensity along the edge normal direction of the standard grid sample in 50X magnification.
FIG. 5. Sigmoid function when m = -0.2, n = 10, K = 200, D = 25.
FIG. 6. 2D sigmoid function for line geometry when the geometry function is . (a) Top view of the function. (b) Isometric view of the function.
FIG. 7. 2D sigmoid function for circle geometry when the geometry function is . (a) Top view of the function. (b) Isometric view of the function
FIG. 8. 2D sigmoid function for ellipse geometry when (a) Top view of the function. (b) Isometric view of the function.
FIG. 9. General optical microscope system using the Piezo Transducer (PZT).
FIG. 10. Indium Tin Oxide (ITO), Half-tone photoresist (HT-PR) and hole pattern images. (a) ITO. (b) HT-PR. (c) Hole A. (d) Hole B.
FIG. 11. Fitting results for line (ITO and HT-PR edge) and circle (Hole A and Hole B edge) pattern. (a) Original intensity of line image. (b) Fitting intensity of line image. (c) Original intensity of circle image. (d) Fitting intensity of circle image.
TABLE 1. Specifications of the measurement system
TABLE 2. CD measurement results from LoG mask sub-pixel method and sigmoid surface fitting method. (a) Measurement results of line width (ITO, HT-PR). (b) Measurement results of circle diameter (Hole A, B).(a) Line width (unit: μm)
TABLE 2. CD measurement results from LoG mask sub-pixel method and sigmoid surface fitting method. (a) Measurement results of line width (ITO, HT-PR). (b) Measurement results of circle diameter (Hole A, B) (Continue).(b) Circle diameter (unit: μm)
참고문헌
- S.-H. Park, J.-H. Lee, and H. J. Pahk, "In-line critical dimension measurement system development of LCD pattern proposed by newly developed edge detection algorithm," J. Opt. Soc. Korea 17(5), 392-398 (2013). https://doi.org/10.3807/JOSK.2013.17.5.392
- N.-T. Doan, J. H. Moon, T. W. Kim, H. J. Pahk, "A fast image enhancement technique using a new scanning path for critical dimension measurement of glass panels," Int. J. Precis. Eng. Manuf. 13, 2109-2114 (2012). https://doi.org/10.1007/s12541-012-0279-9
- N. Xu and Y.-T. Kim, "An image sharpening algorithm for high magnification image zooming," In Consumer Electronics(ICCE) (2010 Digest of Technical Papers International Conference on. IEEE), pp. 27-28.
- A. J. Tabatabai and O. R. Mitchell, "Edge location to subpixel values in digital imagery," IEEE Trans. Pattern Anal. Mach. Intell. 2, 188-201 (1984).
- Q. Sun, Y. Hou, Q. Tan, C. Li, and M. Liu, "A robust edge detection method with sub-pixel accuracy," Optik - International Journal for Light and Electron Optics 125(14), 3449-3453 (2014). https://doi.org/10.1016/j.ijleo.2014.02.001
- J. Ye, G. Fu, and U. P. Poudel, "High-accuracy edge detection with blurred edge model," Image Vis. Comput. 23(5), 453-467 (2005). https://doi.org/10.1016/j.imavis.2004.07.007
- M. Hagara and P. Kulla, "Edge detection with sub-pixel accuracy based on approximation of edge with Erf function," Radioengineering 20(2), 516-524 (2011).
- G.-S. Xu, "Sub-pixel edge detection based on curve fitting," In Information and Computing Science (2009. ICIC'09. Second International Conference on. IEEE), pp. 373-375.
- I. Sobel, "Neighborhood coding of binary images for fast contour following and general binary array processing," Comput. graphics image process. 8(1), 127-135 (1978). https://doi.org/10.1016/S0146-664X(78)80020-3
- A. Huertas and G. Medioni, "Detection of intensity changes with subpixel accuracy using Laplacian-Gaussian masks," IEEE Trans. Pattern Anal. Mach. Intell. 5, 651-664 (1986).
- J. Canny, "A computational approach to edge detection," IEEE Trans. Pattern Anal. Mach. Intell. 6, 679-698 (1986).
- T. T. E. Yeo, S. H. Ong, and R. Sinniah, "Autofocusing for tissue microscopy," Image Vis. Comput 11(10), 629-639 (1993). https://doi.org/10.1016/0262-8856(93)90059-P
- D. L. Marks, A. L. Oldenburg, J. J. Reynolds, and S. A. Boppart, "Autofocus algorithm for dispersion correction in optical coherence tomography," Appl. Opt. 42(16), 3038-3046 (2003). https://doi.org/10.1364/AO.42.003038
- S. H. Fox, R. M. Silver, E. Kornegay, and M. Dagenais, "Focus and edge detection algorithms and their relevance to the development of an optical overlay calibration standard," In Microlithography'99 (International Society for Optics and Photonics, 1999), pp. 95-106.
- J.-H. Ahn, J. Ko, I. Y. Lee, and S. H. Kim, "A fast continuous auto focus algorithm using the state transition model," Pac. Sci. Rev. 13, 125-130 (2011).
- R. L. Plackett, "Karl Pearson and the Chi-squared test," Int. Stat. Rev. 51, 59-72 (1983). https://doi.org/10.2307/1402731