Decided to investigate further to qualify our vendors.
4BGA + 2 circuits and assembly.
Will cross section bare, after paste+reflow, after BGA assembly and also X-ray and dye and pry.
At least I will have fun.
Gaby
  ----- Original Message ----- 
  From: [log in to unmask] 
  To: [log in to unmask] ; [log in to unmask] 
  Sent: Tuesday, January 29, 2008 8:35 PM
  Subject: Re: [TN] Microvoids immersion silver


  Hi Gaby,
  I take it what you are seeing are 'champagne voids.'
  Voids like these are 'encouraged by rough topography copper, excessive Ag thickness, some solder paste choices and rapid cool-down after reflow. But as Donald Cullen says in his comprehensive paper, it "requires the “Perfect Storm” of a rather contrived combination of parameters" to produce planar micro-voiding.
  Well Gaby, now you know it—you are "Perfect." ;-)



  Werner



  **************
  Start the year off right. Easy ways to stay in shape.
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