own peculiarities. Their specific resistance, dielectric permittivity, tangent of the
dielectric loss angle vary greatly. In a number of cases, it is necessary to register the
distribution of material parameters not only over the surface, but also along the
thickness of the structure.
Such diagnostics of modern integrated circuits, which has a high resolution,
involves probing of their individual elements, which can consist of various materials
with the properties of metals, dielectrics, semiconductors, and superconductors.
Measurements of the amplitude and phase of the microwave wave reflected from the
conducting surface make it possible to determine its specific conductivity.
SMM allows us to detect local defects and heterogeneities in integrated circuits.
The detection of residual stresses in semiconductors and metals is based on the
detection of increased specific resistivity in stressed regions due to increased carrier
scattering [8].
In the world, ready-made models of Scanning Microwave Microscopes are
already being manufactured. Specifically, the company Agilent [9] produces them on
the basis of the Atomic Force Microscope (AFM), coupled with a vector network
analyzer (VNA). In this setup, the microwave signal from the VNA passes through the
resonant circuit to the conductive AFM probe, which is in contact with the sample
under study. Also, the probe serves as a receiver for the signal reflected from the sample
at the point of contact. The values of the complex reflection coefficient S11 and total
resistance of the sample at each scan point are measured by the vector network analyzer
and are being compared with the topogram of the surface.
However, the resulting microscope turns out to be quite expensive due to the
present VNA in its setup. A device consisting of a microwave generator, a resonator
measuring transducer and an AFC can replace this device [2, 10-16]. Resonator
measuring transducer (Fig. 1) or RMT is a quarter-wave resonator with an open end
coaxial aperture [11-16].
The central conductor of the RMT is a near-field probe. Due to the near-field
nature of the field arising around this probe, the spatial resolution of the scanning
microwave microscope does not depend on the wavelength, but depends only on the
radius and shape of the probe tip [11, 13]. The distribution of the field in the object
under the central point of the tip along the radius is illustrated in Fig. 2.
It can be seen from the figure that in the case of the spherical shape of the tip the
field is localized directly under the center of the probe, and in the case when the probe
tip has the shape of the truncated cone the field has a tubular character. Also, a strong
dependence of the field in the object from the gap between the tip of the probe and the
surface of the object, and, accordingly, the degree of the object's influence on the
parameters of the measuring system is seen.
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