Hello Jiang;

I experienced similar difficulties and discovered my Au layer was
effectively porous and allowed HF (or other chemicals) to attack the Cr
adhesion layer.  Depending on your deposition technique/tool, you may find
a very thick (4000A in my case for our Ebeam evaporator) layer of Au is
required to fully protect your Cr.  I would recommend increasing your Au
thickness if possible or optimize your Au layer by optimizing the
deposition parameters for your dep tool or consider an alternate
application method (i.e. I would suspect electroplated Au would provide an
improved barrier to chemicals).

Best of luck, Jack

Jack Kotovsky
UC Davis Knee Orthopedics Laboratory


 > Date: Tue, 9 Apr 2002 08:39:45 -0700 (PDT)
> From: Jiang Zhe 
> To: [email protected]
> Subject: [mems-talk] Cr/Au delamination
> Reply-To: [email protected]
>
> I have a 300A Cr/2500A Au delamination problem. Cr/Au
>
> was deposited on p-type Si <100> wafer. Then it was
> put
>
> into concentrated HF and Cr/Au layer were peeled off
>
> after 30 minutes. The pre-clean (RCA clean and a 2min
>
> Ar plasma pre-etch) was well done before sputtering.
>
> My question is, what's the possible reason of the
>
> delamination? Any suggestion? Thanks!
>
> Jiang
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