MT6M14904b
© Fuji Electric Co., Ltd. All rights reserved.
3-2. Application of thermal grease
Thermal grease must be applied between the product mounting surface and the heat sink to ensure
heat dissipation from the product to the heat sink.
If the properties, amount, and application method of the thermal grease are not appropriate, it may
result in poor heat dissipation and lead to thermal failure. Make sure that the thermal grease is
spread over the entire base plate of the product. Also, please check the heat dissipation state of the
module. You can check the extent of spreading of thermal grease by removing the module after
mounting.
Table 4 shows the recommended thermal grease properties and thickness. Assuming that the
thickness is uniform, the required amount (weight) of thermal grease can be calculated from the
following formula.
We recommend using the stencil mask method to control the appropriate thermal grease thickness
(Fig.2). Recommended stencil mask pattern can be provided from a representative of our company or
one of our distributers.
In addition, depending on the type or application method of thermal grease, deterioration or dry out
of thermal grease may occur during high temperature operation or temperature cycle, which may
shorten the product lifetime. Pay attention to the selection and application method of the thermal
grease.
Unit
Recommended value
Penetration (typ.)
-
>= 340
Thermal conductivity
W/m
・
K
>= 1
Thermal grease thickness
μm
100 +/-30
Table 4 Recommended properties of thermal grease
Thermal grease
thickness (
μm)
Thermal grease
weight (g) x 10
4
Mounting surface
area of module (cm
2
)
=
Density of thermal
grease (g/cm
3
)
x
x
Fig.2 Thermal grease application
Squeegee
(for applying thermal
grease)
Thermal grease
(
apply to module’s
base plate)
Stencil mask
Stencil mask
fixing tool
6
