Hi,

In our experience, spin is not a good option on 3D structures
due to non-uniform coating, and in the extreme case uncovered
areas, in the "shadow" of a released structure (which we call
"speedboats" due to the similarity in shape to the trace a fast
boat leaves in water). Spray coating gives better results, but
uniformity on 3D structures is still not good due to surface
tension, which retracts resist from protruding corners and accu-
mulates it in cavities. Spraying is also not suitable for thin
layers (7-10um being the minimum).
We are also working with electrophoretic resist (plating from
a watery solution), which is completely uniform on all surfaces
in all directions - but process and material compatibilities
pose a different set of challenges.
Our structures are big enough that damage due to spinning is
not a problem.
Hope this helps. Greetings from Singapore!

Frank Berauer
Senior R&D Engineer
Hewlett-Packard IJMS Wafer Fab


-----Original Message-----
From: Yong Zhu [mailto:yzhu@northwestern.edu]
Sent: 27 September 2001 14:23
To: mems-talk@memsnet.org
Subject: [mems-talk] spin photoresist after releasing the structure


Hello, MEMS friends;

Does anyone have experience to spin photoresist after releasing the
structure, such as comb drive?
I am wondering if the spin will damage the suspended device. I would like to
get some idea before
I make the design. Thank you.

Yong
_______________________________________________
mems-talk mailing list
mems-talk@memsnet.org
To unsubscribe or change your list options, use:
 http://fab.mems-exchange.org/mailman/listinfo/mems-talk