I disagree. And if you review the TechNet archives, as recommended previously, I think you will see general agreement with the following:
Resin-poor is due to too much volume and not enough resin. If you add more copper, then there is less volume, so the resin can fill it. If you have thin prepregs and thick copper, then there is a higher probability of having resin starvation if you leave out the copper. If you put the copper in, it will squish the resin out into the adjacent void and provide higher resin concentration in the electrical isolation area where you need it.
Leaving the pads in gives better seals as noted above, but can make etching more difficult, especially on plane layers with small backoff. If it's not a "stressed" design (thin prepregs) then I leave the decision to the board fab house.
Wayne Thayer
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Paul Reid
Sent: Friday, January 18, 2013 8:54 AM
To: [log in to unmask]
Subject: Re: [TN] PCB design/build question about via construction
I vote on non-functional pads out. You get an area that is resin poor if you have a stack of non-functional pads. The stack of pancakes, as it were, "telegraphs" the image of the pads to the outer layers. The resin in the stack is depleted because there is copper on every layer.
What we suggest is to leave three or four non-functional pads in but not in the center zone of the board.
Sincerely,
Paul Reid
Program Coordinator
PWB Interconnect Solutions Inc.
235 Stafford Rd., West, Unit 103
Nepean, Ontario Canada, K2H 9C1
613 596 4244 ext. 229
Skype paul_reid_pwb
[log in to unmask]
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of David Bealer
Sent: January 17, 2013 4:13 PM
To: [log in to unmask]
Subject: [TN] PCB design/build question about via construction
On an internal copper plane(pour) where a via intersects the plane but doesn't connect, should we remove the pad on that plane for that via? I would think that it would add some measure of structural support for the via if we left it in place. Am I wrong?
Thanks,
David Bealer
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