ODIN-W2 series - System Integration Manual
UBX-14040040 - R03
Advance Information
Handling and soldering
Page 21 of 33
Soldering Paste
OM338 SAC405 / Nr.143714 (Cookson Electronics)
Alloy specification
95.5% Sn / 3.9% Ag / 0.6% Cu (95.5% Tin / 3.9 % Silver / 0.6% Copper)
95.5% Sn / 4.0% Ag / 0.5% Cu (95.5% Tin / 4.0% Silver / 0.5% Copper)
Melting Temperature
217°C
Stencil Thickness
150
μ
m for base boards
Table 7: Soldering paste information
The final choice of the solder paste depends on the approved manufacturing procedures. The paste-mask
geometry for applying solder paste should meet the recommendations in Module footprint and paste mask
section.
The quality of the solder joints on the connectors (’half vias’) should meet the appropriate IPC
specification.
3.3.2
Reflow soldering
A convection type-soldering oven is strongly recommended over the infrared type radiation oven. The convection
heated ovens allow precise control of the temperature and all parts will be heated up evenly regardless of
material properties, thickness of components, and surface color.
Consider the "IPC-7530 Guidelines for temperature profiling for mass soldering (reflow and wave) processes",
published during 2001. Select the reflow profiles as per the following recommendations:
Failure to observe these recommendations can result in severe damage to the device!
Preheat phase
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: maximum 3°C/s.
If the temperature rise is too rapid in the preheat phase it may cause excessive slumping.
•
Time: 60 to 120 seconds:
If the preheat is insufficient, rather large solder balls could be generated. Conversely, if performed
excessively, fine balls and large balls will be generated in clusters.
•
End Temperature: 150 to 200°C:
If the temperature is too low, non-melting tends to be caused in areas containing large heat capacity.
Heating and 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 to 60 s
•
Peak reflow temperature: 245°C
Cooling phase
A controlled cooling avoids negative metallurgical effects (solder becomes more brittle) of the solder and
possible mechanical tension in the products. Controlled cooling helps to achieve bright solder fillets with a good
shape and low contact angle.
•
Temperature fall rate: max 4°C/s
The modules should be placed on the topside of the motherboard during soldering to avoid falling off.
The soldering temperature profile chosen at the factory depends on additional external factors like choice of
soldering paste, size, thickness and properties of the base board and so on.
Exceeding the maximum soldering temperature and the maximum liquidus time limit in the
recommended soldering profile can permanently damage the module.
