Particle laden polymers are one of the most prominent thermal interface materials (TIM) used in electronics cooling. Most of the research has primarily dealt with the understanding of the thermal conductivity of these types of TIMs. For thermal design, reduction of the thermal resistance is the end goal. Thermal resistance is not only dependent on the thermal conductivity, but also on the bond line thickness (BLT) of these TIMs. It is not clear which material property(s) of these particle laden TIMs affects the BLT and eventually the thermal resistance. This paper introduces a rheology based semiempirical model for the prediction of the BLT of these TIMs. BLT depends on the yield stress of the particle laden polymer and the applied pressure. The BLT model combined with the thermal conductivity model can be used for modeling the thermal resistance of these TIMs for factors such as particle volume faction, particle shape, base polymer viscosity, etc. This paper shows that there exists an optimal filler volume fraction at which thermal resistance is minimum. Finally this paper develops design rules for the optimization of thermal resistance for particle laden TIMs.

1.
Prasher
,
R. S.
,
2001
, “
Surface Chemistry Based Model for the Thermal Contact Resistance of Fluidic Interstitial Thermal Interface Materials
,”
ASME J. Heat Transfer
,
123
, pp.
969
975
.
2.
Gwinn, J. P., and Webb, R. L., 2002, “Performance and Testing of Thermal Interface Materials,” Thermes 2002, Y. K. Joshi and S. V. Garimella, eds., Santa Fe, New Mexico, 13–16 January.
3.
Suddith
,
R. D.
,
1993
, “
A Generalized Model to Predict the Viscosity of Solutions With Suspended Particles. 1
,”
J. Appl. Polym. Sci.
,
48
, pp.
25
36
.
4.
Xu
,
Y.
,
Luo
,
X.
, and
Chung
,
D. D. L.
,
2000
, “
Sodium Silicate Based Thermal Interface Material for High Thermal Contact Conductance
,”
ASME J. Electron. Packag.
,
122
, pp.
128
131
.
5.
Prasher, R. S., Koning, P., Shipley, J., and Devpura, A., 2001, “Dependence of Thermal Conductivity and Mechanical Rigidity of Particle-Laden Polymeric. Thermal Interface Material on Particle Volume Fraction,” Proc. of International Mech. Eng. Cong. and Exp., New York, Nov. 11–16.
6.
Prasher
,
R. S.
,
Koning
,
P.
,
Shipley
,
J.
, and
Devpura
,
A.
,
2003
, “
Dependence of Thermal Conductivity and Mechanical Rigidity of Particle-Laden Polymeric Thermal Interface Material on Particle Volume Fraction
,”
ASME J. Electron. Packag.
,
125
(
3
), pp.
386
391
.
7.
Madhusudana, C. V., 1996, Thermal Contact Conductance, Springer-Verlag, New York.
8.
Das
,
A. K.
, and
Sadhal
,
S. S.
,
1998
, “
Analytical Solution For Constriction Resistance With Interstitial Fluid
,”
Heat Mass Transfer
,
34
, pp.
111
119
.
9.
Zhou, P., and Goodson, K. E., 2001, “Modeling and Measurement of Pressure Dependent Junction-Spreader Thermal Resistance for Integrated Circuits,” Proc. of International Mech. Eng. Cong. and Exp., ASME, New York.
10.
Campbell, R. C., Smith, S. E., and Dietz, R. L., 1999, “Measurements of Adhesive Bondline Effective Thermal Conductivity and Thermal Resistance Using the Laser Flash Method,” Proceedings of 15th IEEE SEMI-THERM Symposium, IEEE, Piscataway, NJ, pp. 83–97.
11.
Fletcher, L. S., and Peterson, G. P., 1986, “The Effect of Interstitial Materials on the Thermal Contact Conductance of Metallic Junctions,” Heat Transfer in Systems Seminar-Phase II, National Cheng University, Tainan, January 13–14.
12.
Shenoy, A. V., 1999, Rheology of Filled Polymer System, Kluwer Academic Publishers, MA, pp. 1–390.
13.
Devpura
,
A.
,
Phelan
,
P. E.
, and
Prasher
,
R. S.
,
2001
, “
Size Effects on the Thermal Conductivity of Polymers Laden With Highly Conductive Filler Particles
,”
Microscale Thermophys. Eng.
,
5
(
3
), pp.
177
189
.
14.
Barnes
,
H. A.
,
1999
, “
The Yield Stress—A review or ‘παϖταρελ’—Everything Flows
,”
J. Non-Newtonian Fluid Mech.
,
81
, pp.
133
178
.
15.
Prasher, R. S., Shipley, J. C., Prstic, S., Koning, P., and Wang, J., 2002, “Rheological Study of Micro Particle Laden Polymeric Thermal Interface Materials: Experimental (Part 1) and Modeling (Part 2),” Proc. of International Mechanical Engineering Congress and Exposition, ASME, New York.
16.
Dienes
,
G. J.
, and
Klemm
,
H. F.
,
1946
, “
Theory and Application of the Parallel Plate Plastometer
,”
J. Appl. Phys.
,
17
, pp.
458
471
.
17.
Grimm
,
R. J.
,
1978
, “
Squeezing Flows of Polymeric Liquids
,”
AIChE J.
,
24
(
3
), pp.
427
439
.
18.
Covey
,
G. H.
, and
Stanmore
,
B. R.
,
1981
, “
Use of the Parallel-Plate Plastometer for the Characterization of Viscous Fluids With a Yield Stress
,”
J. Non-Newtonian Fluid Mech.
,
8
, pp.
249
260
.
19.
Campanella
,
O. H.
, and
Peleg
,
M.
,
1987
, “
Determination of Yield Stress of Semiliquid Foods From Squeezing Flow Data
,”
J. Food. Sci.
,
52
(
1
), pp.
214
217
.
20.
Meeten
,
G. H.
,
2000
, “
Yield Stress of Structured Fluids Measured by Squeeze Flow
,”
Rheol. Acta
,
39
, pp.
399
408
.
21.
Delhaye
,
N.
,
Poitou
,
A.
, and
Chaouche
,
M.
,
2000
, “
Squeeze Flow of Highly Concentrated Suspensions of Spheres
,”
J. Non-Newtonian Fluid Mech.
,
94
, pp.
67
74
.
22.
Buscall
,
R.
,
Mcgown
,
I. J.
,
Mills
,
P. D. A.
,
Stewart
,
R. F.
,
Sutton
,
D.
,
White
,
L. R.
, and
Yates
,
G. E.
,
1987
, “
The Rheology of Strongly Flocculated Suspensions
,”
J. Non-Newtonian Fluid Mech.
,
24
, pp.
183
202
.
23.
Progelhof
,
R. C.
,
Thrones
,
J. L.
, and
Ruetsch
,
R. R.
,
1976
, “
Methods for Predicting the Thermal Conductivity of Composite Systems: A Review
,”
Polym. Eng. Sci.
,
16
(
9
), pp.
615
624
.
24.
Hassleman
,
D. P. H.
, and
Johnson
,
L. F.
,
1987
, “
Effective Thermal Conductivity of Composites With Interfacial Thermal Barrier Resistance
,”
J. Compos. Mater.
,
21
, pp.
508
515
.
25.
Devpura, A, Phelan, P. E., and Prasher, R. S., 1999, “Percolation Theory Applied to the Analysis of Thermal Interface Materials in Flip-Chip Technology,” Proc. of ITHERM, Las Vegas.
26.
Every
,
A. G.
,
Tzou
,
Y.
,
Hassleman
,
D. P. H.
, and
Raj
,
R.
,
1992
, “
The Effect of Particle Size on the Thermal Conductivity of ZnS/Diamond Composites
,”
Acta Metall. Mater.
,
40
(
1
), pp.
123
129
.
27.
Prasher, R. S., Alger, O., and Phelan, P. E., 2001, “A Unified Macroscopic and Microscopic Approach to Contact Conduction Heat Transfer,” Proc. of 35th National Heat Transfer Conference, Anaheim, CA.
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