SU-8 Developing Issue, advice required

[Nan Xie]

Hi,

I am developing SU-8 2050 after spun around 50um.
My procedures for soft baking, exposure, and PEB are correct.
I am having trouble getting clean develops after about 6min and 2-3s acetone spray.
What I am getting are some milky residue around my features. I understand I need to develop it more when this occurs, but this milky residue still remains or the SU-8 would come off.

Anyone have any suggestions? Maybe I need to expose more?

Thank you very much,

Nan Xie
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[Hongjun-ECE]

My guessing...you may need IPA instead of acetone to rinse after the
development. Acetone dissolves the un-cross linked SU8 and leaves something
on your wafer.

Good luck,

Hongjun Zeng, PhD
Microfabrication Application Laboratory (MAL)

-----Original Message-----
From: Nan Xie
Sent: Tuesday, April 19, 2005 7:44 PM
To: MEMSTalk
Subject: [mems-talk] SU-8 Developing Issue, advice required

I am developing SU-8 2050 after spun around 50um.
My procedures for soft baking, exposure, and PEB are correct.
I am having trouble getting clean develops after about 6min and 2-3s acetone
spray.
What I am getting are some milky residue around my features. I understand I
need to develop it more when this occurs, but this milky residue still
remains or the SU-8 would come off.

Anyone have any suggestions? Maybe I need to expose more?
_______________________________________________
Hosted by the MEMS and Nanotechnology Exchange, the country's leading
provider of MEMS and Nanotechnology design and fabrication services.
Visit us at http://www.mems-exchange.org

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[Brubaker Chad]

Nan,

Actually, what you are seeing could very well be a sign of insufficient
cross-link in the film. When fully cross-linked, SU-8 is pretty much
immune to solvent chemistries.

This may indicate either insufficient exposure, insufficient PEB, or
both.

Best Regards,
Chad Brubaker

-----Original Message-----
From: Nan Xie
Subject: [mems-talk] SU-8 Developing Issue, advice required

I am developing SU-8 2050 after spun around 50um.
My procedures for soft baking, exposure, and PEB are correct.
I am having trouble getting clean develops after about 6min and 2-3s
acetone spray.
What I am getting are some milky residue around my features. I
understand I need to develop it more when this occurs, but this milky
residue still remains or the SU-8 would come off.

Anyone have any suggestions? Maybe I need to expose more?
_______________________________________________
Hosted by the MEMS and Nanotechnology Exchange, the country's leading
provider of MEMS and Nanotechnology design and fabrication services.
Visit us at http://www.mems-exchange.org

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[chong hanwoo]

Hi,

The exposure wavelength and the collimation of the exposure light is
critical to get a clean development particularly to resolve
high-aspect-ratio features. You should also check the optial
characteristics of your substrate or any thin metal film on the
substrate at the exposure wavelength you used. Surface with a
reflectivity at the exposure wavelength can also result in
exposure and developing problem.

regards

Han

Post by Hongjun-ECE
-----Original Message-----
From: Nan Xie
Subject: [mems-talk] SU-8 Developing Issue, advice required
I am developing SU-8 2050 after spun around 50um.
My procedures for soft baking, exposure, and PEB are correct.
I am having trouble getting clean develops after about 6min and 2-3s
acetone spray.
What I am getting are some milky residue around my features. I
understand I
need to develop it more when this occurs, but this milky residue still
remains or the SU-8 would come off.

_______________________________________________
Hosted by the MEMS and Nanotechnology Exchange, the country's leading
provider of MEMS and Nanotechnology design and fabrication services.
Visit us at http://www.mems-exchange.org

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To unsubscribe:
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[Dwayne Dunaway]

Nan,

I often see thus issue when I use thicker layers. Like Hongjun, I use IPA to rinse after developing. The solution to the problem, for me, is to spray a stream of developer at the white material then throw it back into the developer for a few more minutes. Repeat this till it is gone. I do not see any noticable degradation in my structures with increased develop time. I believe the instructions from microchem mention this white stuff.

good luck,

Dwayne Dunaway


Nan Xie <***@trlabs.ca> wrote:

I am developing SU-8 2050 after spun around 50um.
My procedures for soft baking, exposure, and PEB are correct.
I am having trouble getting clean develops after about 6min and 2-3s acetone spray.
What I am getting are some milky residue around my features. I understand I need to develop it more when this occurs, but this milky residue still remains or the SU-8 would come off.

Anyone have any suggestions? Maybe I need to expose more?
_______________________________________________
Hosted by the MEMS and Nanotechnology Exchange, the country's leading
provider of MEMS and Nanotechnology design and fabrication services.
Visit us at http://www.mems-exchange.org

Want to advertise to this community? See http://www.memsnet.org

To unsubscribe:
http://mail.mems-exchange.org/mailman/listinfo/mems-talk