Void on soldering

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Board had a via hole underneath of the solder pad of the BGA... - Jul 26, 2007 by Thomas

Choices are: * Respin the board to move the via so that it ... - Jul 26, 2007 by davef

Is the via hole not supposed to be there, or is this by desi... - Jul 31, 2007 by Rafael

... - Jul 31, 2007 by Matt Kehoe

Thomas

#51209

Void on soldering | 26 July, 2007

Board had a via hole underneath of the solder pad of the BGA. When it run through reflow oven, it caused a lot of void. How to correct this issue?

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davef

#51211

Void on soldering | 26 July, 2007

Choices are: * Respin the board to move the via so that it is no longer under the pad. * Have the board fabricator plug and plate over the via.

Search the fine SMTnet Archives for background.

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Rafael

#51259

Void on soldering | 31 July, 2007

Is the via hole not supposed to be there, or is this by design?

If you are trying to fill the via hole with solder and not have voiding issues, I suggest using a type 4 solder powder mesh size. Reason being, anytime you go beyond Type 4 mesh, to something like Type 5 or Type 6 mesh, it becomes much more difficult to have good wetting.

So even though the powder size is smaller, and you would think the hole would be more filled; really what happens, is the surface area from the solder spheres are so much smaller, that the flux used to activate the spheres doesn't help with wetting, and it causes voiding. However, this is a fine balance, because larger spheres like Type 2 and Type 3 can also cause even worse voiding issues....

www.senjucomtek.com

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Matt Kehoe

#51260

Void on soldering | 31 July, 2007

http://www.sipad.com/sipad_vip.htm

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