Via soldermask quality question

Thread Starter

tracecom

Joined Apr 16, 2010
3,944
In the attached photo, there are two vias. The one nearer the top left does not have a good soldermask covering, whereas the one nearer the lower right does have a good soldermask covering. In this particular PCB, it doesn't matter, but in another layout, the lack of a soldermask could be significant.

Should I complain to the PCB house, or is this acceptable?

Thanks.
 

Attachments

Last edited:

mcgyvr

Joined Oct 15, 2009
5,394
Its a VIA not a plated through hole.. soldermask really doesn't matter there..
Did you request vias be "tented" or plugged or anything?
 

Thread Starter

tracecom

Joined Apr 16, 2010
3,944
Its a VIA not a plated through hole.. soldermask really doesn't matter there..
Did you request vias be "tented" or plugged or anything?
I was hoping you would reply because the layout was done in DipTrace.

No, I didn't request anything special. I thought vias were always plated through; isn't that true?

Oh, and I think I saw today that there is an option in Gerber file prep for vias to be left unmasked, but I didn't select that.
 

mcgyvr

Joined Oct 15, 2009
5,394
Vias are always plated through.. What I meant by the "via not a plated through hole" is that the soldermask for a via doesn't really matter like it does for a regular plated through hole.

But how the soldermask is handled for a via is either specified by you (plugged/tented,etc..) or mostly left up to manufacturers discretion.

Some good info here..(just the first link I came across)
http://www.epectec.com/pcb/plug-via/

Id have to see your gerber files but I suspect they were not included in the masking and as such they were going to be "tented" and thats usually never guaranteed to always happen. as you can see

Next time make sure the mask includes via holes if it didn't already... Nothing to be concerned with though..
 

#12

Joined Nov 30, 2010
18,223
Could you guys dumb this down for me? All I see is that (upper) A is not through plated and there's a hair in the soup. Are you saying you wanted the surface rims of the through holes to be painted green?
 

mcgyvr

Joined Oct 15, 2009
5,394
Could you guys dumb this down for me? All I see is that (upper) A is not through plated and there's a hair in the soup. Are you saying you wanted the surface rims of the through holes to be painted green?
He was just expecting both "via" holes to be capped or covered completely with soldermask..
and it IS through plated it just didn't get hot air solder leveled because its partly covered with masking.. the mask just "sank" into the hole more than the other..
 

ErnieM

Joined Apr 24, 2011
8,272
In the attached photo, there are two vias. The one nearer the top left does not have a good soldermask covering, whereas the one nearer the lower right does have a good soldermask covering. In this particular PCB, it doesn't matter, but in another layout, the lack of a soldermask could be significant.

Should I complain to the PCB house, or is this acceptable?
First you should check the mask layer gerber file and see if there is a hole over that via, but without any other fill I wouldn't expect a via to fill 100% of the time with the mask material.

I say check the gerber as it appears to me the mask is simply non existent on that "via," and perhaps it is just a small thru hole. I've had that happen in my projects when I change the via size mid way.

It doesn't hurt to query your board house and ask suggestions for times this is a serious error (as opposed to simply not desirable but well tolerated).

Could you guys dumb this down for me? All I see is that (upper) A is not through plated and there's a hair in the soup. Are you saying you wanted the surface rims of the through holes to be painted green?
I cannot tell from the image if the thru holes are plated or not.

An angle to the board would help show the innards. It may also let the hairball fall off.
 
Top