Solder mask top/bottom for pad

Discussion in 'General Electronics Chat' started by aamirali, Dec 17, 2013.

  1. aamirali

    Thread Starter Member

    Feb 2, 2012
    415
    1
    What should be recommended value of solder mask for pads.
    Like if I have 100mil pitch throgh hole connector or 0805 capacitor for which I have to make solder mask.

    It largely depend on manufacturing process but I want to know recommended values.
     
  2. eeabe

    Member

    Nov 30, 2013
    59
    9
    In my experience, the minimum required by the manufacturers has worked very well. We've used 3 mil expansion on each side of the pads, or 6 mil larger diameter or width, etc. I believe it's just to ensure the PCB manufacturer doesn't get the soldermask on the pads based on their process margins.
     
  3. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    Agreed... it is based on the tolerance your PCB vendor can handle. Do ask his recommendations, since while he may be able to keep a .01 mil tolerance he can process 3 mil for 1/100th the price.

    If it's your first board don't be surprised to see the mask disappear in places, such as between closely spaces IC pads.
     
  4. t06afre

    AAC Fanatic!

    May 11, 2009
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  5. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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