To better answer this question need a few answers to following:
What is the backing on the die,
what is the metallization on the substrate,
what is the max process temp you can withstand,
what is the service environment,
what sort of application is it
and so on,
can you /do you use flux in the bonding operation,
what sort of power handling/frequency is the circuit to handle?
Finally why did you originally use Au/Sn?


 Mike


> ----- Original Message -----
> From: jong s kadesch <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Monday, June 12, 2000 2:37 PM
> Subject: [TN] GaAs Cracks
>
>
> Hi Technetters,
>
> Recently, I have attached GaAs die on a CVD diamond substrate using 80/20
> Au/Sn eutectic preform.  After the die bonding at 280 C, we found cracks
> (mostly 90 degrees and 45 degrees cracks) on the surface of the GaAs during
> the inspection.  We suspect that it is due to TCE mismatch or thermal
> shock.  We are thinking about using different die attach material that
> requires lower temperature process.  Anyone has advise, suggestion, or any
> experience similar to this?  Thanks.
>
>
> Jong S. Kadesch

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