This is an ideal application for Xenon Difluoride etching.  It may not be
as fast as you like but it should work.  Contact me at your convenience if
you would like to discuss this further.  Phone 650 569 3655 x16.
Greg Ortiz
Surface Technology Systems

----------
> From: Geng Chen 
> To: MEMS@ISI.EDU
> Subject: Selective release etch of Al sacrificial layer
> Date: Monday, January 11, 1999 5:28 PM
>
> Hi there,
>
> We would like to release an Al sacrificial layer (0.5 5m thickness)
without
> affecting any
> other metal and dielectric layers in the structure.  An undercut rate of
100
> 5m+ in 10
> min. is required.  The etchant should not attack PE oxide, nitride, Ti,
Au.
> Any suggestions?
> Your help will be very much appreciated.
> Regards,
>
> G. Chen
>