
CLP270M
20/24
Fig 36 :
Typical reflow soldering heat profile
Time (s)
Temperature ( C)
0
40
80
120
160
200
240
280
320
360
0
50
100
150
200
250
o
215 C
Soldering
Preheating
Cooling
245 C
Epoxy FR4
board
Metal-backed
board
SOLDERING RECOMMENDATION
The
soldering
process
thermal stress to a semiconductor component.
This has to be minimized to assure a reliable and
extended
lifetime
of
PowerSO-10
TM
package can be exposed to a
maximum temperature of 260°C for 10 seconds.
However a proper soldering of the package could
be done at 215°C for 3 seconds. Any solder
temperature profile should be within these limits.
As reflow techniques are most common in surface
mounting, typical heating profiles are given in
Figure 36, either for mounting on FR4 or on
metal-backed boards. For each particular board,
the appropriate heat profile has to be adjusted
experimentally. The present proposal is just a
starting
point.
In
any
precautions have to be considered :
- always preheat the device
- peak temperature should be at least 30 °C
higher than the melting point of the solder
alloy chosen
- thermal capacity of the base substrate
causes
considerable
the
device.
The
case,
the
following
Voids pose a difficult reliability problem for large
surface mount devices. Such voids under the
package result in poor thermal contact and the
high thermal resistance leads to component
failures. The PowerSO-10 is designed from
scratch to be solely a surface mount package,
hence symmetry in the x- and y-axis gives the
package excellent weight balance. Moreover, the
PowerSO-10 offers the unique possibility to control
easily the flatness and quality of the soldering
process. Both the top and the bottom soldered
edges of the package are accessible for visual
inspection (soldering meniscus).
Coplanarity
between
the
package can be easily verified. The quality of the
solder joints is very important for two reasons : (I)
poor quality solder joints result directly in poor
reliability
and (II) solder thickness affects the
thermal resistance significantly. Thus a tight
control of this parameter results in thermally
efficient and reliable solder joints.
substrate
and
the