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July 1997

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Subject:
From:
Michael Barmuta <[log in to unmask]>
Reply To:
Date:
Fri, 25 Jul 1997 14:40:10 -0700
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TEXT/PLAIN
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TEXT/PLAIN (66 lines)
	Carlos: I've seen this same type of adhesion problem after I.R 
fusing. Depending on which interface is failing Au to Ni or Ni to Cu the 
causes are different. Without knowing what your process chemistries and 
sequences are for Sn strip,activation,and Deep/Tab Ni-Au electroplate I'll 
take a couple of guesses. If the failure is Ni to Cu and you're using a 
non-fluoride/peroxide Sn strip such as a nitric based system an intermetallic 
could be left behind. This could give you a sufficient enough bond of the 
plated Ni to Cu to pass a tape test after plate but when subjected to the 
thermal shock and stresses of HAL the Ni/Cu bond could be degraded. This 
would result in a failure in a post HAL tape test. If the failure is Au to Ni 
I would suspect more of a passivation problem with the Ni or incorrect entry 
amperage into the Au electroplate causing the adhesion problem after HAL.	
									
There's a long list of possible problems and solutions for "gold peelers" but 
the key piece of information in your problem is it's happening only after HAL 
and passing the post plate tape test fine. More information on the 
type/severity of failure and additional process information would help to 
further pinpoint the problem. You may also want to make sure the tape test is 
being conducted the same at both test areas. Old tape, incorrect type of 
tape, technique of application and removal can all affect the results of the 
test									
						Regards			
							Michael Barmuta	
							Staff Engineer	
							Fluke Electronics	
							Everett Wa.	
							425-356-6076  
On Fri, 25 Jul 1997 09:50:24 -0700 [log in to unmask] wrote:

> From: [log in to unmask]> Date: Fri, 25 Jul 1997 09:50:24 -0700
> Subject: Gold peel after solder level
> To: [log in to unmask]
> 
>      Hello!
>      Has anyone experienced Deep or Tab gold plate passing tape test at the 
>      precious metal process, only to have gold peel after the Hot Air 
>      Solder Level process.
>      
>      Thanks
>      
>      Carlos
> 
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