Can two wafers be successfully bonded with total Au/Sn thickness of ~1-2
um or less?  In the literature I've reviewed on the subject the thinnest
metal stacks are ~4um (total for both wafers), with most in the range of
5-10um.  It's not clear why such thick layers are used.  Other wafer
bond techniques often use much thinner layers e.g. Au thermocompression
bonds can be accomplished with 1um films.

Will Au-Sn bonds survive exposure to TMAH or KOH Si etch?


Thank you

Roger Shile