Ravi;

I read your inquiry and wonder if you have had any responses.
I am doing a study of those that do, and your information would
shorten my study.

What I do know is that most people use a preform [AuSn] and scrub
the die. There have been some people who have tried sputtered
AuSn on the backside of the wafers/die. They seem to have problems with
that approach. Packaging house have steered me away from sputtered
backside to preforms and scrubbing.

Bill Beecher
DB2 Products
831-684-1630