On the failed boards you cross sections, did the copper pl Rush, On the failed boards you cross sections, did the copper plating have an "hour-glass" shape (i.e., thicker near the outer-layers and thinner in the middle)and were the cracking approximately in the vertical center of vias? Also, were the cracks in the barrel plating or was there separation of the barrel plating from internal layers? Regards, George George M. Wenger Andrew Corporation Wireless Network Solutions Senior Principal FMA / Reliability Engineer 40 Technology Drive, Warren, NJ 07059 (908) 546-4531 [Office] (732) 309-8964 [Cell] -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of [log in to unmask] Sent: Sunday, October 14, 2007 4:15 PM To: [log in to unmask] Subject: Re: [TN] SV: [TN] URGENT HELP NEEDED:- non-destructive method for via hole pl... George, Werner, These are unpopulated brds. YES THERE ARE CPNS ON THE PANEL.(as per IPC-2221) 1) CPNS SHOW more than 0.0015" mini in the via holes (in cpns representing via holes) 2) However, some assy have failed due to cracked copper. 3) 2 assy were X-sectioned and showed low copper ~ 0.001" in the vias that cracked. (these are vias in the brd)... we do have pretty good plating quality....we check tensile elongation every 2 wks and elongation always runs > 20%. 4) We X-secitoned some scrap brds...via plating was fine. 5) SO WE feel that, some brds may less plating in these via holes even though the cpns show adequate plating. 6) HENCE WE WANT TO MEASURE COPPER PLATING IN VIA HOLES (IN A BARE BRD) NON_destructively. Rush 818-415-0030 In a message dated 10/13/2007 4:55:02 PM Pacific Daylight Time, [log in to unmask] writes: I haven't see your product but just knowing the board i Hi Rush, I haven't see your product but just knowing the board is a 20-layer 150 mils PCB with a 1.5 mil thick copper requirement for the vias it sounds like this isn't a cheap assembly. I guess that is the reason you're looking for a non-destructive measurement. Unfortunately I don't think you are going to find a non-destructive technique for measuring the copper thickness in vias on a fully populated PCBA. Werner's comment about a "classic case" is correct. In fact I would add to his statement and say that a non-populated PCB retention sample is always a good idea as is non-destructive measurements on bare PCB's prior to assembly. Regards, George George M. Wenger Andrew Corporation Wireless Network Solutions Senior Principal FMA / Reliability Engineer 40 Technology Drive, Warren, NJ 07059 (908) 546-4531 [Office] (732) 309-8964 [Cell] -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Werner Engelmaier /* Sent: Saturday, October 13, 2007 7:30 PM To: [log in to unmask] Subject: Re: [TN] SV: [TN] URGENT HELP NEEDED:- non-destructive method for via hole plating thickness Hi Rush, Here is a classic case as to why it is imperative to have coupons as part of the panel. you state: 20 layers, ~150 mils thick Via holes are 20-22 mils finished; Required plating is 0.0015 min. Also, for via holes, the finished hole size is totally unimportant-you need to know the drilled hole size. Is the required plating thickness 1.5 mils minimum? or measures how? You also do not say whether you have problems, and what the problems are. 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