There is actually a problem with trying to use AZP4620 to that thickness, and
one of the other responders alluded to it - transparency.

For layers thicker than about 15 - 20 µm, you'll already start to see some
issues with light penetration into an AZP4620 film (the develop behavior becomes
much less linear).  Beyond 25 µm, you begin to have extreme difficulties in
clearing the bottoms of exposed regions, because the light is just not
penetrating that far.

The suggestion of AZ9260 is a good one - this was AZ's (or Clariant's, at the
time) update to AZP4620, once it became apparent that people were using the
material for thicker-and-thicker films.  Its two primary differences from
AZP4620 is greater transparency (I've produced 5:1 aspect ratios) and an
included leveling agent to produce smoother and more uniform films.  I myself
have single coated this material to 65 µm thick, and patterned it (my minimum CD
was somewhere between 10 and 15 µm).


Best Regards,
Chad Brubaker


-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of ???
Sent: Tuesday, June 03, 2008 5:10 PM
To: [email protected]
Subject: Re: [mems-talk] 20um features using AZP4620

you can use spray coating

"Haixin Zhu"  writes:
>Dear all,
>
>I am trying to produce 20um features using AZP4620, the thickness is
>required to be 38um, I tried double coating/triple coating with various
>spin speed and baking condition, and they did not work. Is there any one
>having this experience and advise me on the right direction?