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san2004
Joined: 26 Jun 2007
Posts: 18
Helped: 1
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 17 Jun 2008 17:38 PLUGGED VIAS |
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Dear frnds,
For mass-production of 6 layers boards which type of vias are best ?
We have told them for expoed vias but they are asking whether to plug them with solder mask or just cover them with solder mask ?
What are the advantages of plugging vias with solder mask & should we do that ?
Thanks in advance,
Byeeee
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Anonymous_Ricky
Joined: 26 Dec 2006
Posts: 146
Helped: 7
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| 18 Jun 2008 9:13 PLUGGED VIAS |
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Hi ,
You can go through the following thread posted on this forum
http://www.edaboard.com/ftopic270664.html
Ricky
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whiplash
Joined: 22 Jun 2006
Posts: 18
Helped: 2
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| 18 Jun 2008 15:06 PLUGGED VIAS |
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You don't plug using solder mask.
You plug your vias shut with various conductive materials (silver, specially formulated paste, etc.)...but not epoxy.
Plugging your vias (with conductive material) will allow for better connectivity, and the holes will be free of corrosion over time.
Tenting (plugging with solder resist) helps to assemble fine pitch components (BGAs) as it reduces the possibility of shorts, but other than that there are no real advantages that I can tell. You may even have problems with chemistry getting down in the barrel of the via and corroding it over time.
Really depends on the type of board you are producing. If they are not high density boards I would recommend leaving them exposed.
my 2 cents.
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san2004
Joined: 26 Jun 2007
Posts: 18
Helped: 1
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| 20 Jun 2008 16:58 Re: PLUGGED VIAS |
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Dear frnds,
When i asked this question to the vendor that by using which conductive material they are going to pluug the vias ? But I got the answer that " They are going to plug in vias with SOLDER MASK including all vias under ICs".
Will it affect on working of boards ?
Thanks in advance.
Byee...
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whiplash
Joined: 22 Jun 2006
Posts: 18
Helped: 2
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| 20 Jun 2008 19:51 PLUGGED VIAS |
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See my paragraph on Tenting...
Your boards will work fine.
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FvM
Joined: 22 Jan 2008
Posts: 2632
Helped: 431
Location: Bochum, Germany
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| 21 Jun 2008 11:02 Re: PLUGGED VIAS |
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As whiplash, I'm not aware of plugging with solder mask as a usual technology. However, there are different purposes of plugging that may have different solutions:
- stop solder wicking with exposed pad vias
- increase thermal conductivity of vias
- increase electrical conductivity of vias
- place via in pad with full electrical and mechanical function, e. g. in a 0.5 mm/20 mil BGA pad
I have previously used this types of plugging
- via fill with nonconductive material, surface treatment and solderable galvanic copper cover (supplied by Ilfa, Germany and Merix, USA)
- via fill with thermal conductive material, surface treatment, non-solderable surface (cheaper than first solution, supplied by Wuerth, Germany)
I think, that filling vias with solder mask could be possible for specific solder mask processes. I doubt, if it achieves clean, solderable surface around the via, e. g. for an exposed pad. If so, it could be an interesting via fill variant. Can you, respectively the said manufacturer, give photos showing the via finish details and also tell the applicable via parameters (drill size, aspect ratio)?
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