Hi Ben:
Why not use flux to attach the balls?
If you use solder it could alter somehow your ball diameter and ball
property since SAC solder is Sn rich and your ball is high lead. Pb will
react with Sn and gradually affect the solder joint property between
solderball and SAC solder (This is a reliability risk).
In the past we have tried this and our solder ball collapsed due to Sn and
Pb reaction, but since your BGA solder mask defined, maybe you can maintain
your ball height but i doubt if you can maintain ball uniformity/planarity

regards
J.Noquil
Senior Member Technical Staff
CSD




On 6/25/08, Stadem, Richard D. <[log in to unmask]> wrote:
>
> Hi, Ben
> Good question. I checked with the Power PC data sheets
> http://ieeexplore.ieee.org/iel3/3906/11336/00514354.pdf?arnumber=514354
> and they do not specify how they attach their 90/10 balls to the
> package, but I suspect some type of high-temp alloy is used. I do not
> believe they reflow the balls directly to the package pads. But I never
> did know what they use to solder the balls to the package with. Let me
> know if you find out.
>
>
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Gumpert, Ben
> Sent: Tuesday, June 24, 2008 12:42 PM
> To: [log in to unmask]
> Subject: [TN] SAC solder on Pb90Sn10
>
> Technetters,
>
> Does anyone have any experience (or heard of) using SAC solder to attach
> high-temp (Pb90Sn10) solder balls to a ceramic BGA?
>
> Ben
>
>
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