BGA Heat Thermal

[randychase]

From Phillip Restall

Hi All


I had a Cpci board I designed come back with rework problems due to having
my Gnd planes on outer layers.
The problem is our Bga rework station takes a lot longer to remove parts on
this board with
the additional copper which in turn causes problems with other Bga's in
close proximity.
On this new revision I have come up with an idea to pen in Bga's with small
circular voids in the copper so it-
1. Should keep the heat local and Remove the device quick.
2. stop a lot of the heat being dispersed to other Bga pads


Any comments on this would be appreciated.


http://www.pcbstandards.com/images/planethermal.jpg

[mdldesign]

What you've done here is a great idea, can I use it!?

I would question the need for all the ground spokes on each pad. Reducing these would reduce the amount of time the hot air was used (and heating other parts), which could be more of a problem then the copper conductivity.

Mark
MDL Design

[phillipr]

Feel Free to use it!!
I agree some Bga's have to many thermals on at the moment
I will renove the error.

[phillipr]

Randy

Thanks for Posting the picture.