Hi David, 

Some PCB suppliers will drill and plate the filled holes first (then fill, cure and planarize); then they go back and drill and plate the non-filled holes. This means the outer layer will see two plating cycles so, depending on your line width/space requirements some PCB suppliers will need to reduce the starting foil weight (for example if you want Hoz + plating, you may need to go to 1/3 oz + plating to get desired final Cu thickness).  

But other suppliers drill and plate everything at once, and then selectively fill the target holes, in which case there is no need to adjust. So you might want to ask about their process flow for via-in-pad. 

Also, check out IPC-6012, Section 3.6.2.11.2, which defines acceptable cap plate, and dimple and bump thicknesses. 

Todd


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of David Bealer
Sent: Tuesday, April 23, 2013 9:17 AM
To: [log in to unmask]
Subject: [TN] Via in pad using filled or plugged vias

We are looking at the possibility of using boards designed with vias in pad and having those vias filled.  What should we be concerned with? ( I know this is a overly broad question, just looking for a place to start.)

Thanks,

David Bealer
SMT Department Manager
office 800-637-2645 x6022   cell 217-474-8760
email [log in to unmask]<mailto:[log in to unmask]>

Watchfire Headquarters  *  watchfiresigns.com<http://www.watchfiresigns.com/>
sales 800-637-2645   service 866-637-2645


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