SEM probe defocusing method of measurement of linear sizes of nanorelief elements

Abstract

The new method of measurement of linear sizes of nanorelief elements is presented. The applicability of this method to linear measurements of nanorelief elements with trapezoid profile and wide and small inclination angles of side walls is demonstrated. The results of developed method and direct measurements are compared. Examples of measurements of linear sizes of relief pitch structures are given.

Electron distribution density in a low voltage SEM probe

“…Defocusing breaks this con vergence. Therefore, the use of the defocusing tech nique [15] for measuring the sizes of nanostructure elements requires thorough analysis and verification of the results obtained.…”

“…Taking into account infinity of the medium along the Y direction, we may express the secondary emis sion signal [5,6] as (11) where n(X, T = 0) is the electron distribution density in the probe, T is the probe center position at a given instant of time (scanning coordinate), and I(X) is the function describing the emission properties of the pro trusion surface, which is determined by the relief of this surface (12) where I 1 , I 2 , and I 3 are the constants independent of X and satisfying the conditions (13) Having differentiated expression (11) over the scanning coordinate with regard to (12), we arrive at (14) in the coordinate region of point X 1 and (15) in the coordinate region of point X 2 . Positions of points X 1 and X 2 relative to the structure are shown in Fig.…”

“…In addition, the probe defocusing technique for measuring ultra small sizes in scanning electron microscopy was developed [15]. Obviously, the electron distribution density in the probe changes upon defocusing.…”

Novel method for dimensional measurements of nanorelief elements based on electron probe defocusing in a scanning electron microscope

“…We studied characteristics of the method of defocusing of the electronic probe when determining geometric parameters of a reference measure 'MShPS-2.0K' [6,7]. The measure represents several pitch structures located on a silicon surface which coincides with the (1 0 0) crystallographic plane of silicon.…”