Melvin,

It is likely that your wafers are not flat enough as you suspect. For
Bonding- wafers should have TTV < 2um and preferablly <1um- which is
best obtained with Double Side Polished wafers.

Ken

Melvin DeSilva wrote:
>
> Hello,
>
> I need to do Au-Au thermal compression bond using Karl Suss bonder.
> Sometimes the bonding is not uniform across the wafer.  I understand
> that it could have been caused by particles on the wafer or film
> uniformity, etc.  My question is:
>
> Is there a requirement for wafer flatness (TTV less than ?? um) in order
> to achieve a uniform bond.  Any comments and suggestions are appreciated.
>
> Melvin
>
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