Patent ID: 7427756
Filing Date: 2008-09-23
Classification: G06T

Abstract:
1. A method of measurement of microsizes of relief objects in scanning electron microscope with use of analytical models, comprising the steps of: 1.1 storing an SEM image of a measurement object on a physical carrier or a memory of a computer in digital form for subsequent processing; 1.2 selecting from the stored image which represents a dependency of a value of a video signal S from coordinates x and y in a field of vision of the microscope-S(s, y), a signal line representing a dependency of the video signal S from the coordinate S with a constant value of Y-S(x) which is an experimental video signal S 1.3 determining a number of parameters of an analytical model which represents a system of equations, substantially fully characterizing a geometry of the relief object, its composition and characteristic of the measuring SEM; 1.4 assigning to each of the parameters a credible numerical value selected with consideration of a preliminary information about an object and the microscope; 1.5 with the use of said equations of analytical model and an additional approximation, calculating a model video signal of an initial approximation S(°), which imitates the experimental video signal S 1.6 with the calculated video signal S(°) bringing the calculated video signal X(°) comparing it with the scale experimental video signal S 1.7 comparing the normalized video signal with the experimental video signal in 1.8 introducing into initial numerical value of a size Lo a disturbance 6LO so that a new value of the size L1 is equal to L 1.9 selecting a first perturbed model video signal S 1.10 if the video signal S 1.11 introducing into the value L 1.12 varying the value L, selecting a value which provides a best approximation model-signal to the experimental video signal so that said value of the model object is an actual model of a physical object measured in correspondence with the direction x SEM image; 1.13 repeating the steps 1.1-1.12 for all other lines of the stored SEM image so as to obtain information which allows to make a judgment about changes of sizes of objects along a direction y, and also about its shape and details of a parameter and also allowing to determine an average value of a size of an object and its dispersion which statistically characterizes a non-homogeneity of the width of the object or a line width roughness.