On Sat, 12 Aug 2006, Jeff Walther wrote:
Date: Fri, 11
Aug 2006 15:58:16 -0600
From: "e.stiebler" <emu at e-bbes.com>
Chuck Guzis wrote:
On 8/11/2006 at 4:37 PM shoppa_classiccmp at
trailing-edge.com wrote:
I suspect that the legacy DIP stuff will get
harder to buy new through
"normal" channels, given RoHS. In the long run, I suppose we'd all
better
get used to working with surface mount. :(
Yup, get ready to solder .2 mm balls on 800 balls BGA.
Get your toaster-oven ready ;-)
BGA components have a specification for the clearance between the chip
package and the circuit board after soldering. I don't think you could meet
that just by putting the thing in the oven.
Thats entirely determined by the package weight and surface tension (assuming
the solder balls are all melted), If you do it by hand you can see the BGA
package 'sink' when all the balls are melted. So you can do it with an oven, a
simple hot air gun or probably even a propane torch if you are skilled enough.
I have done many successful BGA protos with nothing more than a $59.00 Granger
hot air gun.
and actually the commercial SMT equipment bears a large resemblence to a
glorified toaster oven...
BGA's are not all that hard to do with simple hand tools.
However, it might be interesting to get some feeler guages the same thickness
as the clearance that that specification calls for, place the feeler guages
around the edges of the chip between the chip and the board and then heat the
chip and board until the chip presses down on the feeler guages. That
*should* give the proper clearance and therefore the appropriate solder ball
"squish".
I don't know how one reballs BGA components though. Anyone care to explain?
Jeff Walther
Peter Wallace
Mesa Electronics
(\__/)
(='.'=) This is Bunny. Copy and paste bunny into your
(")_(") signature to help him gain world domination.