Here's a thread from another site that is discussing BGA pad cratering:

http://tinyurl.com/nw46xh

And something that comes from Trace Labs Technical Library Document
discussing BGA Pad Cratering:

http://www.tracelabs.com/TechLibraryDoc.aspx?id=78

Genny's BGA crater isn't as extreme as some of the examples, it is
cratered...or starting to.

Steve

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
Sent: Monday, June 15, 2009 12:12 PM
To: [log in to unmask]
Subject: Re: [TN] image adjusted

Hi Joe,
 
I think that the last image that Genny sent me was darker than the first
two so that you could see that the solder ball was soldered fine at the
device to ball interface and at the ball to pad interface. I don't think
there was anything wrong with the solder joint...
 
I believe that the cratering she was talking about was shown in her
first two photos in the laminate just beneath the PCB pads
 
http://stevezeva.homestead.com/files/crack_bright_100x.jpg
 
http://stevezeva.homestead.com/files/crack_bright_200x.jpg
 
Genny, correct me if I'm wrong?
 
Steve

________________________________

From: [log in to unmask] [mailto:[log in to unmask]]
Sent: Monday, June 15, 2009 11:37 AM
To: Steve Gregory
Subject: image adjusted


Hi Steve
 
I adjusted the image to see better. Other than the small voids I am
curious what is being seen. There seems to be no cratering 
 
Cheers, 
Joe

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