Why would you think the copper beneath the 6-8 microinches would corrode?  If you're not using a nickel barrier to prevent copper diffusion my guess sould be that the copper from beneath would diffuse to the surface and oxidize when it is exposed to the enviornment.  But then again the fluxes and sodler paste being used are usually formuated to reduce copper oxide so why worry.



-----Original Message----- 

From: Ray Klein [mailto:[log in to unmask]] 

Sent: Wed 8/14/2002 8:41 PM 

To: [log in to unmask] 

Cc: 

Subject: [TN] corrosion on gold flashed PCB's







Guys, 



We use 6-8 micro inch of gold flash over copper on our surface layers. 

Mostly these areas are covered with solder paste and don't cause a problem. 

We are considering using large areas of the board as heat sinks without 

solder paste and are concerned with corrosion of the copper underneath this 

very thin gold layer. Has anyone tested for or had experience with this? 



Ray Klein 



JNI 

10945 Vista Sorrento Pkwy 

San Diego, CA 92130 



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