Cheol-Hyun:

I've patterned PIX3400 without problems, using AZ4210.  I'd suggest that
you soft bake the polyimide at 90 C for 20 mins 9in an oven)  Skip the
130C step.  spin the photoresist and pre-bake again at 90C.  I used MIF
312  (1part : 4 parts water)to etch the resist.  The difference between
the two solvents is  normality.  If you cannot lay your hands on 312,
use diluted 319 (1:4) and see how you go.

hope this helps

Shekhar

Cheol-Hyun Han wrote:
>
> Hi,everybody;
>    I have had hard time to pattern the polyimide with normal positive PR.
> I'm using PIX3400 from HD MicroSystem and following the process based on
> their info.   But, I found it's hard to pattern the PR on polyimide.
> It looks like that some chemical reaction between polyimide and PR layer
> was happened and then it was not patterned by PR developer anymore.
> If I use negative PR, it's a little easer than positive to pattern but
> still not as easy as just pattern PR on wafer.
>    If anyone know how to pattern polyimide(PIX 3400)properly with normal PR
> process, please let me know and  any information should be welcomed.
> Thank you.
>
>    One more thing I'd like to be confirmed is etchant which I use for
> both developing the PR and etching the polyimide.   I'm using diluted
> MF-319(MF319:DI water=1:1).   Is it O.K. or I need to use something special?
>
> By the way, I have used following process.
>
> 1. spin coating the polyimide(2500rpm/30sec for 20um thick)
> 2. prebake(90C/10min + 130C/30min)
> 3. spin coating the PR
> 4. Prebake(90C/30min)
> 5. Exposure
> 6. resist development and polyimide etching(immersion)
>         30C/10mins
>

--
Shekhar Bhansali Ph.D.
Senior Research Associate
CMSM, University of Cincinnati
PO Box 210030
CINCINNATI OH 45221-0030
PH: (513) 556-1997 Fax: (513) 556 7326