Shiv,

I'm not a MEMS expert so I don't know what you want to do. Is the SU-8
supposed to be permanent. If so the 4620 should go on top. I also assume
that the SU-8 developer is a solvent which will dissolve the AZ 4620. If you
need a thick sacrificial resist you will need one that does not dissolve in
the SU-8 developer. You will need to talk to the manufacturers to to find
the compatible materials.

Bill

----- Original Message -----
From: "Shiv GD" 
To: 
Sent: Wednesday, January 04, 2012 12:40 PM
Subject: [mems-talk] SU-8 2025 on AZ 4620 Sacrificial Layer


> Hello Everyone,
>
> I am working on a Microchannel device, and facing some problem with AZ
> 4620
> and SU-8 Layer. The device is fabricated on a glass substrate and I am
> using AZ 4620 as sacrificial layer ( I need ~20um height). I patterned the
> AZ layer using standard lithography process ( Spincoat, Bake on Hotplate
> for 2mins @ 110'C, Expose and Develop using AZ 400K. ) and I want to keep
> it until the last step. I than, spincoat SU-8 2025 (on top of the AZ 4620
> layer), bake, expose, post bake. But when I try to develop the SU-8
> structure ( using Microchem SU-8 developer ), I observe that the SU-8
> structure develops alright but the AZ sacrificial layer is gone. As a
> result the SU-8 structure collapse, cracks and I can't continue to the
> next
> step.
>
> What do you think I can do to resolve the situation ? Please suggest.
>
> Your help is much appreciated.
>
> Thank you.
>
> Shib