reballing BGA's

[Jamie Morken]

Hi all,

I am needing to do some BGA rework and I am thinking of reballing the
BGA by using the stencil to apply solderpaste on the BGA pads and then
baking it in the toaster oven to create the BGA solderballs. The
alternative seems to be to buy a vial of solder balls and place them on
the BGA. Anyone see any problems with the solderpaste method?

Also I was wondering why solderpaste is required on the PCB's before
soldering the BGA's on? The BGA's already have solderballs, so why not
just apply a bit of flux to the board and place the BGA on that? I
guess that it is less reliable to do this? I also read about people who
do BGA rework reusing the solder on the PCB, so maybe pretinning the PCB
would work.. thanks,

cheers,
Jamie

 

[Boris Mohar]

On Fri, 05 Nov 2004 06:00:34 GMT, Jamie Morken <jmorken@shaw.ca> wrote:

Also I was wondering why solderpaste is required on the PCB's before
soldering the BGA's on? The BGA's already have solderballs, so why not
just apply a bit of flux to the board and place the BGA on that? I
guess that it is less reliable to do this? I also read about people who
do BGA rework reusing the solder on the PCB, so maybe pretinning the PCB
would work.. thanks,

cheers,
Jamie

The assembly house that I use http://www.miselectronics.com/ does not require
solderpaste for BGA.



Regards,

Boris Mohar

Got Knock? - see:
Viatrack Printed Circuit Designs http://www3.sympatico.ca/borism/

 

[Georg Acher]

Boris Mohar <borism_-void-_@sympatico.ca> writes:

On Fri, 05 Nov 2004 06:00:34 GMT, Jamie Morken <jmorken@shaw.ca> wrote:

Also I was wondering why solderpaste is required on the PCB's before
soldering the BGA's on? The BGA's already have solderballs, so why not
just apply a bit of flux to the board and place the BGA on that? I
guess that it is less reliable to do this? I also read about people who
do BGA rework reusing the solder on the PCB, so maybe pretinning the PCB
would work.. thanks,

cheers,
Jamie

The assembly house that I use http://www.miselectronics.com/ does not require
solderpaste for BGA.

AFAIR it depends on the BGA type if you actually need solder paste. Heavy
packages cannot have balls made of regular melting solder (eutectic) but need a
non-melting solder (non-eutectic). Otherwise the weight would squeeze the
melting balls to much...

--
Georg Acher, acher@in.tum.de
http://wwwbode.in.tum.de/~acher
"Oh no, not again !" The bowl of petunias