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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


trace surface finish

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Rod

#70702

trace surface finish | 6 September, 2013

Why do PCB traces need a surface finish? On microstrip (top/bottom) the solder mask does not help

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#70710

trace surface finish | 8 September, 2013

PCB designers specify the application of solder mask [eg, varnish, solder stop mask, solder resist, etc] to fabricators to reduce the potential of bridging between two conductive traces during assembly soldering processes [eg, wave, reflow and hand soldering].

BR, davef

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Rod

#70711

trace surface finish | 8 September, 2013

I read an article about signal integrity losses and ENIG applied to all of the traces on the board. Doesn't solder mask protect the traces? Why would you need ENIG on the entire board?

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#70713

trace surface finish | 8 September, 2013

Protect the board: If solder mask protects the board, the level of protection is limited and inconsistent. If you want protection, you need the be thinking conformal coating.

Selective ENIG: I believe the reason solderability protection, except maybe SMOBC, is applied over the whole board is that it's cheaper than masking portions of the board.

BR, davef

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#70732

trace surface finish | 9 September, 2013

Hi, rod,

The exposed copper area you could do with ENIG. It is with good solderability.

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