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Fri, 2 Oct 1998 10:31:13 +0800 |
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DSO National Laboratories |
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I am very curious to know:
1. Is it true that solder will definitely flow through a PTH via?
2. What if the via hole is small enough to prevent this capillary effect? Does that means PTH via is still
OK?
3. How small a via hole will be for (2)?
Kelly M. Schriver wrote:
> Hi Scott -
>
> The via in pad is a problem UNLESS it's a microvia which only goes a layer or
> two deep in the board. Vias which go all the way thru the board will steal
> solder from the connection you're trying to make on one side, then turn that
> same solder into a nice spherical bead on the opposite side.
>
> The inspectors and touch up people, in turn, have lifetime job security.
>
> Regards - Kelly
>
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