The THERMAN program

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The THERMAN program
Quick thermal simulator for IC-s and certain MEMS
structures solution algorithm is based on the
Fast Fourier Transform

• rectangular sandwich structure,
• any number of homogenius layers,
• any number of orthogonal polygon shaped 2D
  dissipators on any layer surface,
• calculation of heat-sinking effect of heat
  conducting bonding wires (lead-effect
  algorithm)
• different boundary conditions at the sidewalls,
  top and buttom surfaces,
• steady state and frequency domain solutions,
  complete chip characterization

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The model
The structure
Rectangular block, Arbitrary number of
layers Arbitrary number of dissipating
shapes Burried dissipating shapes are
permitted Heat conducting bonds are modelled
Boundary conditions
Sidewalls isothermal or adiabatic Top surface
adiabatic Bottom surface isothermal,
adiabatic or semi-infinite medium with a given
heat conductivity
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The solution algorithm

• Uses Fourier-expansion method
• 2D cosine or sine expansion (depending on the
  sidewall boundary conditions)
• The general form of the temperature field is
• The expansion is calculated by FFT algorithm

for the i-th layer.
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Application example I

Thermal simulation of an IC
The thermal transfer impedance between a given
T(s) location and a dissipator on an IC chip
surface was investigated. The thermal Bode plot
and the Nyquist diagram (locus) of the above
structure was calculated by THERMAN.
The locus of the transfer impedance (Nyquist
diagram) calculated by THERMAN
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Application example II electro-thermal
simulation of integrated circuits

The THERMAN program is part of the SISSI
electro-thermal simulation package. Its major
role is the thermal characterisa-tion of an IC
for the the thermal model generation.
THERMAN
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Electro-thermal simulation of IC-s

THERMAN is also used in the SISSI electro-thermal
si-mulation package for presenting steady-state
temperature distribution. It is able to
commu-nicate with the de-sign framework in order
to draw iso-thermal lines over the chip layout.
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Application example III thermal simulation of
MEMS structures
Temperature distribution of a bridge and a
membrane. The same dissipation pattern has been
specified for both structures.
Membrane suspension at the entire perimeter
Suspension
Bridge suspension at two opposite edges
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Another simulation example
A membrane suspended on two narrow necks
Simulation was performed with the lead-effect
algorithm. The necks were modeled as thermal
resistors.