Hi,
I just wanna add one comment here from my experience on thick
resist process. I have used AZ4330 resist, which is a bit thinner than
AZ4620 but still in the range of 3-6um. I also had some bubbling issue
localized in the exposed regions in some cases and this was how I solved
them:
1) bubbling after exposure with unproperly cleaned or previously-
processed wafers: the solution is of course to use fresh and properly RCA
cleaned wafers.
2) bubbling during post-exposure bake: delay for 15 to 30mins after
exposure before doing PEB.
In general, I found that softbaking on vacuum hotplate at 110C for
3min is effective in evaporating the solvents. Hope this helps.
Isaac
On Mon, 11 Aug 2003, Luigi Corti wrote:
> Hi everybody,
> I have been working with the photoresist AZ4620. I do want to get 8um thick
and my unexpose area 10um-wide lines, which give a large exposed area.
> My problem is that I always have bubbles after the exposure. I did split my
exposure time in several small periods with delays of 30sec in between. Even
though I still get those bubbles. I addition, I checked after the first second
of exposure and most of the bubbles are there by this time. I start to thinking
about the baking time, and reduce it without success.
> If anyone of you had work successfully with AZ4620, please can help with ideas
to solve this problems or with a working recipe. I really appreciate any input.
thanks
>
> Giancarlo Corti,
> Graduate Student, Mechanical Engineering
> University of Idaho, POBox: 0902
> Moscow, ID 83844-0902
> Phone: (208) 885-4996
> email: [email protected]
> [email protected]
> http://www.uidaho.edu/~cort4258
>
>
>
>
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Yours sincerely,
Isaac Chan
Ph.D. Candidate
Dept. Electrical & Computer Engineering
University of Waterloo
200 University Ave. W
Waterloo, Ontario, Canada
N2L 3G1
Tel: (519) 729-6409, ext. 6014
Fax: (519) 746-6321
[email protected]
http://www.ece.uwaterloo.ca/~a-sidic
