When we've specified heavy copper vias in the past it required button plating and planarization to maintain a workable total outerlayer Cu thickness. In the words of our supplier "it's complicated, but at least it's expensive." At 08:26 AM 10/16/2008, Dennis Fritz wrote: >Surprised no one has mentioned the plating of surface features at >the same time as plating copper in?the holes (plating shut).? There >will be some pad around the lip of the hole, and this will plate >very thick - what is the diameter of the via holes?.? Say they are >10 mils, to plate them shut, you will have about 5 mil high surface >features at the surface pads.? That is assuming a good copper bath >that plates 1:1 in the hole and on the surface.? Then, your fab shop >will have to sand down the surface to remove most of the 5 mil high >"rims" around the holes.? And, you say components are above the vias >- you want very planar circuit traces under those, not 5 mil "lumps".? > >You are approaching the technology of "wrap" plating, which not all >shops can do routinely.? > >Denny Fritz >MacDermid, Inc. > > >-----Original Message----- >From: Dave Connitt <[log in to unmask]> >To: [log in to unmask] >Sent: Thu, 16 Oct 2008 10:35 am >Subject: Re: [TN] Problems with plating vias closed > > > >Hi Pete, >This is a research/development project. The vias are currently tented, >plus some are under a couple of 100 pin QFP's. I would have to move the >vias out from under the FPGA's or risk solder balls once I untented >them. Since this is a development project, I doubt they will spin the >board again unless there is some other issue. We rarely wave solder >boards anymore as there are very few thru hole parts on them anymore. >The wave was a great way to fill vias with solder. Ah, the good old >days.. >Dave Connitt CID+ >Printed Circuit Designer >KDI Precision Products, Inc. >A Wholly Owned Subsidiary of: >L3 Communications >3975 McMann Road >Cincinnati, Ohio 45245 >Ph. 513- 943-2010 Fax 513-943-2288 > > >-----Original Message----- >From: Pete Houwen [mailto:[log in to unmask]] >Sent: Thursday, October 16, 2008 9:36 AM >To: [log in to unmask]; Connitt, Dave @ KDI >Subject: Re: Problems with plating vias closed > >Is this just a matter of closing the holes? Rather than having your PCB >supplier try to plate the holes full, can you let them (partially) fill >during soldering? > >--------------------------------------------------- >Technet Mail List provided as a service by IPC using LISTSERV 15.0 >To unsubscribe, send a message to [log in to unmask] with following text in >the BODY (NOT the subject field): SIGNOFF Technet >To temporarily halt or (re-start) delivery of Technet send e-mail to >[log in to unmask]: SET Technet NOMAIL or (MAIL) >To receive ONE mailing per day of all the posts: send e-mail to >[log in to unmask]: SET Technet Digest >Search the archives of previous posts at: http://listserv.ipc.org/archives >Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for >additional information, or contact Keach Sasamori at [log in to unmask] or >847-615-7100 ext.2815 >----------------------------------------------------- > > >--------------------------------------------------- >Technet Mail List provided as a service by IPC using LISTSERV 15.0 >To unsubscribe, send a message to [log in to unmask] with following text in >the BODY (NOT the subject field): SIGNOFF Technet >To temporarily halt or (re-start) delivery of Technet send e-mail to >[log in to unmask]: SET Technet NOMAIL or (MAIL) >To receive ONE mailing per day of all the posts: send e-mail to >[log in to unmask]: SET Technet Digest >Search the archives of previous posts at: http://listserv.ipc.org/archives >Please visit IPC web site >http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional >information, or contact Keach Sasamori at [log in to unmask] or >847-615-7100 ext.2815 >----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------