In a message dated 06/12/2000 3:29:46 PM Central Daylight Time,
[log in to unmask] writes:

> Hi All,
>
>  We are checking placement of some PBGA's. I have an ERSAScope on a demo,
>  and when viewing the solder balls/joints of the BGA there is some
>  "scaling" on the surface of the ball.
>  I was wondering what this scaling is a function of (e.g. to rapid
>  cooling, not hot enough, to hot during reflow?), and is it a defect I
>  should be worried about. I am not seeing this "scaling" on any of the
>  other parts (QFP100, 0603 chips) on the board.
>  Can anyone offer any advice?
>  Thanks
>  David

Hi David!

Does the demo unit you have the ImageDoc software package with it? I believe
it should have "ball scaling" images contained within it that you can compare
what you're seeing with on your board the library of images...I may be wrong.

I remember during the brief demo that I had, that "ball scaling" is a defect.
Problem is, I can't remember if it's caused by being almost, but not quite
hot enough, or too hot...

(Lotta help I am, huh?)

The ImageDoc software should tell you what the possible causes are, that's
supposed to be the beauty of it, you see something that doesn't look quite
right, and then go to the library to see if it's really a defect and what the
causes are. If the software isn't on your demo unit (or it hasn't been
updated yet) ...your Ersa rep should be able to tell you. I know they've done
a lot of work to quantify what we can now see (that we haven't been able to
before) and whether or not it's a defect.

I do remember that "ball scaling" is not a good thing...

-Steve Gregory-

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