Its true that lift-off would avoid the etching step altogether, but if
the adhesion of the Au layer is not great then the problem will be
even worse.

Ti is often used to enhance adhesion, but its by no means guaranteed
to work. Especially if the evaporation environment is not very clean,
evaporating Ti can make adhesion even worse. I would first determine
if the layer that is being etched, adheres properly to the polymer
layer and if not optimize the deposition step before changing anything
with the etch step.

-mikas


On Tue, Jan 12, 2010 at 8:38 AM, Bill Moffat
 wrote:
> Metal lift off leaves metal where you want and none where you want none.
> Contact me for a number of technical papers at
> bmoffat@yieldengineering.com.  Bill Moffat.
>
> -----Original Message-----
> From: mems-talk-bounces@memsnet.org
> [mailto:mems-talk-bounces@memsnet.org] On Behalf Of delas lee
> Sent: Tuesday, January 12, 2010 6:34 AM
> To: mems-talk@memsnet.org
> Subject: [mems-talk] Wet etching gold
>
> Hello;
>
> I tried to make wet etching of gold evaporated on thin layer of Titanium
> on Polymer substrate.
>
> But the gold layer don't stick very well on substrate, because after
> etching with cyanides, it remove all the gold on surface substrat even
> that covered by sacrifice layer.
>
> I am looking for a process that leaving gold sticks very well on polymer
> substrate.
>
> Thank you for your time.
>
> DELAS Lee