Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

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Solder Voids

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#55978

Solder Voids | 14 August, 2008

Hi All,

I encountered mosfet with solder voids as shown in the attached file(X-ray photo). Its happen mostly at this power mosfet area..Any idea to eliminate this defect?

Thanks in advance, Sean

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kpm

#56032

Solder Voids | 18 August, 2008

Let me guess lead free?

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#56035

Solder Voids | 18 August, 2008

This can be seen on leaded soldering also as well as LF (worse with LF).

To reduce this you can look at your stencil and profile.

Printing a cross-hatch deposit can reduce the voiding as it allow gasses to release when in reflow - thats the theory...anyway.

Profile - lean more towards a ramp,soak,spike - reduce DeltaT across PCB - in particular between the D-Paks and lighter parts. Will depend on how your paste can cope with longer soak....

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