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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


mask finish and solder balling

Nithy

#12545

mask finish and solder balling | 19 February, 1999

We are in the process of getting into no-clean paste and fluxes. One important issue in this is sodler balling. I have heard some people say that having a matte finish would help in having lesser solder balls and that the solder balls would not be able to cling onto the solder mask. Could anyone give me more information about this? Is this correct? is there any literature to refer to (either for or against that statement)?

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Tufty

#12546

Re: mask finish and solder balling | 20 February, 1999

| We are in the process of getting into no-clean paste and fluxes. One important issue in this is sodler balling. I have heard some people say that having a matte finish would help in having lesser solder balls and that the solder balls would not be able to cling onto the solder mask. Could anyone give me more information about this? Is this correct? is there any literature to refer to (either for or against that statement)? | Nithy,

One of the basic premises behind the matte mask is that is it can hold more flux and has no smooth surface for the solderball to cling to. the more flux that is available thr less likely you are to have solderballs. the gloss mask's have a nice smooth surface so give plenty of scope for the ball to 'grab' onto whereas the matte has peak's ( there are some good SEM pic's around to show these) the solderball cant get a purchase so fall's off. There are also some thought's on the colour,light mask or dark..maybe another discussion.

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