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August 1999

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Subject:
From:
"Ingemar Hernefjord (EMW)" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Mon, 30 Aug 1999 16:30:54 +0200
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Sqeeeak, sqeeak, yiell, yiell, whimp, whimp, I give up, you are right, Hans. MIL people won't like acidous residues under the BGA. I have seen what can happen: the solder bump's lead be lead away as ions into the soup and then Merlin makes the soup to nice cabbage crystals, as I mentioned earlier. You know Apple's symbol, will look something like that on one side of the bumps. The only solution I will recommend hereafter is Lipton's tea with a little milk added for cleaning under BGAs. The guy with the 20 different white residues will be disappointed: we will never have the time to dig so deep into the white residues, just find fastest way to avoid them. Visited a Motorola course once, was about BGA soldering. They underlined one issue time after time: paste application (many methods) is the key to it all, if properly done, residues will be a minor problem. Queer enough the most lead-drained BGAs were from Mota, but I don't thing there is a connection, they just happened be in front of the Pb-badger. If you
We will probably get further assistance from a MIL qualified lab next door. If there is a final BGA residue story to tell, we will let you readers know. 
-----Original Message-----
From: Hans.Hinners 
Sent: den 25 augusti 1999 17:08
To: Ingemar.Hernefjord
Cc: Hans.Hinners
Subject: RE: [TN] BGA solder residues


>   Ingemar,
> 
> Will the MIL people scream?
> 
	Arrrrgggggghhhhh.

	An unofficial scream from a MIL person.

	Hans
 

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