Yu. A. Novikov

Linear Standard for SEM–AFM Microelectronics Dimensional Metrology in the Range 0.01–100 μm

Linear standards for the calibration of SEMs and AFMs are reviewed. Requirements to a surface pattern designed to serve as a universal standard for the above purpose are defined. A trapezoidal pitch structure is proposed, in which the sidewalls of basic units essentially make a large angle with the normal to the surface. Its uses in SEM–AFM dimensional metrology are considered. A new, universal standard implementing the structure is described. Its certification is briefly reported. SEM and AFM experiments with the standard are presented.

Silicon test object of the linewidth of the nanometer range for SEM and AFM

The results of the study of a test object on scanning electron microscopes and atomic force microscopes are presented. The test object presents a relief on a monosilicon surface, and it is fabricated by the anisotropic etching of monosilicon. The relief elements have a trapezoidal profile with large angles of inclination of the sidewalls. The sides of the relief elements coincide with the crystallographic planes {100} and {111} of silicon. The test object is intended for calibration of scanning electron microscopes and atomic force microscopes.

SEM linewidth measurements of anisotropically etched silicon structures smaller than 0.1 µm

Scanning electron microscopy (SEM) is a standard method for linewidth (CD) metrology. For structure sizes smaller than 0.1 µm the information volume of the scanning electron probe is of the same order of magnitude as the structure size and the resulting SEM signal profile is a superposition of structural information from the whole structure. Evaluation of top and bottom linewidths needs to take into account the electron diffusion in the solid state. SEM linewidth measurements at anisotropically etched silicon structures with an exact edge slope angle of 54.7° and a top linewidth smaller than 0.1 µm were performed by a low-voltage SEM metrology system. Different algorithms were applied for linewidth evaluation which were especially adapted for measurements at small structures. The results of SEM linewidth evaluation were compared among each other and to AFM measurements performed by a large-range scanning probe microscope.

Measurement of dimensions of resist mask elements below 100 nm with help of a scanning electron microscope

We studied the effect of focusing of the electron probe of a scanning electron microscope (SEM), operating in the mode of collection of slow secondary electrons, on the form of a signal obtained when scanning elements of nanorelief of two kinds of objects with electron probe: (a) resist masks, and (b) protrusions and trenches on silicon. The shift of the positions of the points of reference, the distance between which is usually used to determine the size of the relief elements, was observed. The linear dependence of such distance on the size of the electron probe was found. We propose a method to measure the width of the nanorelief element, based on the extrapolation of this linear dependence to the zeroth size of the electron probe. With the help of this method, we measured the widths of nanorelief elements of resist masks, as well as of protrusions and trenches on silicon.

Influence of deformation and chemical structure on elementary free volumes in glassy polymers

Abstract In the scope of the mechanism of positronium formation in polymers before trapping by elementary free volumes (EFV), we demonstrate an approach to quantitative analyses of experimental results. Correspondingly, a relation between the EFV concentration and annihilation characteristics (lifetimes and intensities) is derived. We use PATFIT and CONTIN analyses of positron annihilation lifetime spectra and obtain information on some heterogeneity of the structure of glassy polymers and on the mechanism of the plastic flow of glassy material.

First Russian standards in nanotechnology

The problem of ensuring uniformity of measurements in nanotechnology is discussed. A functional block diagram is developed for length unit size transfer from the primary length standard (meter) to the nanometric range. The first six Russian national standards are presented, which ensure this transfer using scanning electron and atomic force microscopes.

Defining the parameters of a cantilever tip AFM by reference structure.

A method of measurement and control of atomic force microscope (AFM) probe parameters is offered. The AFM real cantilever parameters are defined.

Metrology of vlsi critical element sizes

Methods are surveyed for measuring the critical dimensions of VLSI components. The General Physics Institute of the Russian Academy of Sciences has developed a method that meets the requirements for metrological support up to the year 2010 as set out in the National Technology Roadmap for Semiconductors of the USA.

Imaging of a Test Object with a Trapezoidal Profile and Large Side Wall Inclinations in a Scanning Electron Microscope in the Backscattered Electron Mode

Analysis of imaging of relief pitch structures with trapezoidal profile of relief elements and large side wall inclinations has been carried out in scanning electron microscope in the modes of collection of secondary slow electrons and backscattered electrons. It is shown that the forms of signals of secondary slow electrons and backscattered electrons depend on the structure-element position: close to the pitch-structure edge or far from it. However, the behavior of the signal parameters is independent of the element position. It is demonstrated that the sizes of the parameters of backscattered electron signals characterizing the bottom bases of protrusions and trenches are determined by the true sizes of the bottom bases of the structure elements. At the same time, the sizes of the parameters of the backscattered electron signals that characterize the top bases of protrusions are larger, while those of the trenches are smaller than the sizes determined by the true sizes of the top bases of protrusions and trenches.

Nanoscale dimensional metrology in Russia

We discuss the formation of the system of nanoscale dimensional measurements in Russia. The traceability of the nanoscale measurements to the primary standard of the unit of length (the meter) is shown. Russian state standards that provide the standardization basis for such dimensional measurements are discussed.