LEA-M8F - Hardware Integration Manual
UBX-14000034 - R03
Early Production
Information
Product
handling
Page 20 of 30
4
Product handling
4.1
Packaging, shipping, storage and moisture preconditioning
For information pertaining to reels and tapes, Moisture Sensitivity levels (MSL), shipment and storage
information, as well as drying for preconditioning see the
LEA-M8F Data Sheet
Population of Modules
When populating the modules, make sure that the pick and place machine is aligned to the copper pins
of the module and not on the module edge.
4.2
Soldering
Soldering paste
Use of "No Clean" soldering paste is strongly recommended, as it does not require cleaning after the soldering
process has taken place. The paste listed in the example below meets these criteria.
Soldering Paste:
OM338 SAC405 / Nr.143714 (Cookson Electronics)
Alloy specification:
Sn 95.5/ Ag 4/ Cu 0.5 (95.5% Tin/ 4% Silver/ 0.5% Copper)
Melting Temperature: 217 °C
Stencil Thickness:
See section 2.1
The final choice of the soldering paste depends on the approved manufacturing procedures.
The paste-mask geometry for applying soldering paste should meet the recommendations.
The quality of the solder joints on the connectors (’half vias’) should meet the appropriate IPC
specification.
Reflow soldering
A convection type-soldering oven is highly recommended
over the infrared type radiation oven.
Convection heated ovens allow precise control of the temperature, and all parts will heat up evenly, regardless
of material properties, thickness of components and surface color.
As a reference, see the "IPC-7530 Guidelines for temperature profiling for mass soldering (reflow and wave)
processes”, published in 2001.
Preheat phase
During the initial heating of component leads and balls, residual humidity will be dried out. Note that this
preheat phase will not replace prior baking procedures.
•
Temperature rise rate: max. 3 °C/s. If the temperature rise is too rapid in the preheat phase it may cause
excessive slumping.
•
Time: 60 - 120 s. If the preheat is insufficient, rather large solder balls tend to be generated. Conversely, if
performed excessively, fine balls and large balls will be generated in clusters.
•
End Temperature: 150 - 200 °C. If the temperature is too low, non-melting tends to be caused in areas
containing large heat capacity.
Heating/ Reflow phase
The temperature rises above the liquidus temperature of 217°C. Avoid a sudden rise in temperature as the slump
of the paste could become worse.
•
Limit time above 217 °C liquidus temperature: 40 - 60 s
•
Peak reflow temperature: 245 °C
