Dear Erkin,

I do know of several places that have created close to 40:1 aspect
ratio's in SU-8 using near UV exposure with close control on the process
parameters... Including Sandia, Professor Wanjun Wang at LSU and
Professor Kyle Jiang at the University of Birmingham in the
UK...However, these processes may not be suitable for high volume
manufacturing where throughput is a parameter that needs to be
considered...

Here at MicroChem I can create features down to between 5 to 10um in a
100um thick film of SU-8/SU-8 2000...For these relatively thick films of
SU-8 I use a multi coat process so that the final coat (the one that is
in contact with the mask) is as uniform as can be...If I attempt to
create 100um in a single coat the edge bead is huge and the overall film
uniformity is not acceptable to me...I also use a spray-puddle
development technique to get the best resolution and structure integrity
out of the process....

If you have any specific questions or need technical assistance please
do not hesitate to contact me....

Best regards,

------------------------------------
MicroChem Corp.
Mark Shaw
Epoxy Business Unit - Sales and Technical Support Manager
[email protected]
1254 Chestnut Street
Newton, MA 02464
tel: 617-965-5511 ext 308
fax: 617-965-5818
mobile: 617-407-9490
www.microchem.com
------------------------------------


Message: 3
Date: Sun, 11 Dec 2005 15:44:55 +0800
From: "Peng JIN" 
Subject: Re: [mems-talk] SU8 maximum aspect ratio
To: "General MEMS discussion" 
Message-ID: <[email protected]@hit.edu.cn>
Content-Type: text/plain;       charset="gb2312"

Dear erkin,

I have succeeded to obtain 40:1 in 1000um, and someone in Sadia has
succeeded to obtain about 60:1 in 700um.

best regards

Peng

>Hi,
>
>I want to build vertical SU8 beams on a silicon or quartz substrate,
and I
>would like to have an idea about the maximum aspect ratio I can get
with
>thick (>100um) SU8 resist to yield near vertical sidewalls and intact
>structures.  Could anybody please forward his/her idea on this?
>