Don't use any of those or you won't have much metal left ... suggest you use
an epoxy stripper solvent or progressive sectioning with grinding,
polishing, visual examination of sliced up components.  Contact me off line
& I'll give you phone numbers, etc for some suppliers of such products.
Sheila Smith, Tracor AES



At 03:58 PM 7/23/97 -0500, you wrote:
>
>I'm using  Copper Lead frame (plated copper over Alloy 42) and Silver strip
>layer for die and wire bonding area. This is for SOT 23/ SC 59 packages.
>
>We just notice that the incomming leadframe is having intermittant 'missing
>silver' problem. Unfortunately about 20K products have been molded
>(incapsulated).
>
>Now i want to Decapsulate (remove the mold compound) some sample to identify 
>how serious the problem is. 
>
>What chemical/solution is best to do this work. The solution should NOT attack
>the Copper and silver layer. Thus I can identify the missing silver area
>products.
>
>Fuming Nitric Acid?, Fuming Sulfuric acid?, Mix 50-50 ?
>
>Appreciate yr inputs.
>
>Regards
>Mohd Misri
>Seremban BIM
>
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