User's Manual

Page 48
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Time 25°C to maximum temperature
8 minutes max.
4.3.2. Maximum Temperature and Duration
The following limits are recommended for the SMT board-level soldering process to attach
the module:
• A maximum module temperature of 245°C. This specifies the temperature as
measured at the module’s top side.
• A maximum duration of 30 seconds at this temperature.
Please note that while the solder paste manufacturers' recommendations for best
temperature and duration for solder reflow should generally be followed, the limits listed
above must not be exceeded.
Frey M1 is specified for one soldering cycle only. Once Frey M1 is removed from the
application, the module will very likely be destroyed and cannot be soldered onto another
application.
4.4. Soldering Process Evaluation
4.4.1. Visual Inspection
As a rule, automated optical inspection (AOI) of solder joints is not suitable for evaluating LGA
modules, because most of the I/O pins are hidden underneath the module. Inspection of the
outermost I/Os is not sufficient to evaluate soldering. Please reference IPC-A-610 standard.
4.4.2. X-Ray Inspection and Void Content
X-Ray inspection is an appropriate method for evaluating solder joints after reflow. X-Ray
images can show wetting problems, missing solder volume or of course bridging.
X-Ray inspection is made somehow more difficult by overlaying module components and by
possible bottom side (application) assemblies. However, module connections are
characterized by their shape and size, so in most cases they can easily be distinguished from
the mentioned overlaying structures.