Hi Jim,

I understand that a specification gives everyone the "legal" definition
of what is acceptable. If you bring reliability into the picture you
determine what works. It would be good if the two approaches worked in
concert. 

Since I understand that we are measure the electroless and the
electrolytic copper together, should the spec read electroless copper
plus .0002" of electrolytic copper?

Check out this fabricators electroless copper thickness. This is on a
PTH not a buried via but you see the double electroless, a  Cu flash and
another low build electroless.



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] <mailto:[log in to unmask]> 


-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of Monarchio,
James
Sent: August 25, 2010 2:06 PM
To: [log in to unmask]
Subject: Re: [IPC-600-6012] wrap and electroless

Paul - I understand your position but the spec states plating and total
Cu is total Cu. We are not supposed to read into it more than it says.

Jim

-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of Paul Reid
Sent: Wednesday, August 25, 2010 12:40 PM
To: [log in to unmask]
Subject: Re: [IPC-600-6012] wrap and electroless

I have to agree with Roberto, electroless should not count in the
thickness measurement of wrap. There are times when there are double
electroless copper layers. Some times we see double electroless copper
with exotic PWB constructions. I think one of the larger electroless
copper suppliers suggests double processing on a high build electroless.
That means electroless could be up to 50% of the minimum thickness
requirement. 

It is my subjective opinion that the electroless copper does not
directly add to the robustness of the wrap (unless of course it is
missing). Two mils of electrolytic copper has been demonstrated to be
robust in reliability testing. Less then .002" is usually a reliability
liability.

Best regards,

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] <mailto:[log in to unmask]> 


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