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  1. #1
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    Masking on VIAS ?

    Hi,
    I wanted to know that "Is it a good pratice of giving the vias, a soldermask ink"
    &
    How the PCB manufacturer test the track having VIAS which are covered with soldermask ink (i.e. green masked) .

    The manufacturer, green mask the vias after Electrical Testing or there is another process?

    •   Alt19th December 2006, 13:17

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  2. #2
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    Re: Masking on VIAS ?

    Hi,

    Solder masking the pcb is to avoid the shorts and oxidation. shorts are possible while its goin for reflow assembly after fabrication,it is must for production boards.

    whereas in the prototype it is not required to mask the boards since lots of testing will be going on till its ready for mass production hence they choose via filler.

    Solder masking is just the thin layer over the finished board,while via filler is used to fill in the via holes for protect from the shorts caused during assembly.

    They test the board after solder masking with flying probes,other alternative for solder mask is Via Filler as i told u earlier.

    Some fabricators use both the methods for better protection for eg,assume u have a bga and vias underneath,best way is to fill the via with filler and then soldermask
    the board by this it is more protected from short.

    you can have this document from the Pcb Fabricator,they may help you on this regard.

    Thanks & Regards

    Ramesh


    1 members found this post helpful.

    •   Alt20th December 2006, 04:18

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  3. #3
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    Re: Masking on VIAS ?

    hi Ramesh,

    Thanks for sharing the Knowledge.But i m not able to see the attachment.
    Plz send the link if u have ???



    •   Alt20th December 2006, 13:52

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  4. #4
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    Masking on VIAS ?

    I have seen very few pcbs with masking via.
    If u do not mask the via,u can use via as a test pad.



  5. #5
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    Re: Masking on VIAS ?

    hi,
    I agree with ramesh .if you go for wavesoldering it is more benefit by covering mask to vias.
    bye



  6. #6
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    Re: Masking on VIAS ?

    Actually you can mask the via holes, if you are not using them for testing.

    PCB manufacturer tests boards from end point to end point, unless you want 100% testing, so he will not use via holes.

    Electical testing at PCB house will be done after all the processes completes (except finishing coating in some cases)

    PCB via holes can be masked with soldermask ink or you can ask the fabricator to plug the via holes from any one of the sides, most likely on the BGA component sides.

    I hope this will answer all your queries.



    •   Alt22nd December 2006, 09:42

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  7. #7
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    Re: Masking on VIAS ?

    It seems that you are building a board with BGA chips.
    The fanout vias under the BGA package are masked!



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