LCMAP thermal imaging system

1
LCMAP thermal imaging system

• Computer controlled measurement system, using
  liquid crystals
• nematic-isotropic phase change of the liquid
  crystal that takes place at a specific
  temperature (clearing point) and can be observed
  in polarised light
• low clearing point temperture, no histerasis
• temperature resolution downto 0.05 K (with
  precise termostat), spatial resolution about 2 mm
• evaluation of measurement results by image
  processing techniques

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• The measurement station

The LCMAP measurement station consists of a PC, a
thermostat and a camera attached to a microscope.
The PC controls the termostat temperature and
grabs micro-scopic images by the camera about the
IC surface cove-red by liquid crystal. In
polarised light the regions war-mer than the
clearing point of the liquid crystal are dark.
By changing the termostat temperature the regions
also change, according to the isothermal lines of
the original temperture field of the IC,
resulting from its own static dissipation.
Complete temperature maps are composed by image
processing from the individual snapshots.
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• Presentation of the measured surface temperature
  distribution

The measured temperature distribution can be
displayed on the PC screen in various forms. On
this pseudo color image the temperature
difference between adjecent isotherms
(T1-T2-T3-T4-T5) is 0.16 oC. The thermal map is
displayed together with the IC layout.
4

• Presentation of the results

Different image processing techniquest are used
to display the measuredsurface temperature
distribution in different ways, such as this
relief-like image. Temperature distribution along
a cross-sectional line can also be plotted as a
diagram.
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• Presentation of the results

• Temperature distribution of a BiCMOS OpAmp
  (CA3130) presented by
• isothermal lines,
• pseudo color image,
• relief-like image.