To John Anselmo 

The Xilinx wash spec recommends baking afterwards to assure the part is dry. In practice blow out the water with an air gun to assure there is no water under BGAs, the heated board will then dry. 

The hot water 140-145F will safely dissolve the OA flux from the other components and posses no risk to BGAs. 



However from a processing time, double handling and risk damaging or knocking off bottomside SMT chip components in the wash  you may want to consider putting on the post wave parts with a No-Clean flux pen. Just flux the topside holes prior to inserting the part with the flux pen. If the customer doesn't allow any No-clean residue then 3M makes an excellent cleaner that the operator can use after hand solder. The product flow continues and uses less racks etc. 

If you would like info on a safe cleaning mat designed for cleaning SMT boards in an in-line aqueous cleaner that prevents all of the aqueous cleaning/board handling related issues just E-mail me.  

John Goulet 

MFG/Process Engineer 

  
----- Original Message ----- 
From: "John Anselmo" <[log in to unmask]> 
To: [log in to unmask] 
Sent: Thursday, December 2, 2010 11:59:53 AM 
Subject: [TN] DI Wash of Xilinx BGA 

Hi all, 

  

I have a processing question.  We are building a CCA with a Xilinx 256 
ball BGA. 

The problem is there will be some components added after the BGA is 
placed. 

Normally we used water soluble flux in hand add. 

Is it okay to wash the CCA's with the BGA already placed? 

  

I found some information in the archives (one email string recommending 
sealing the BGA to prevent water from getting under the lid). 

Any other issues with a DI water wash? 

  

Thanks, 

  

John 

  


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