[labnetwork] Photomask sticks to SU8

[pennell at cnf.cornell.edu]

Hi Long,

Having worked with SU-8 for many years I can state that the process guidelines provided by the company are just that - Guidelines. I always advise longer than prescribed bakes after spinning. The main objective is to drive out the carrier solvent.  I have spun layers of SU8 up to 750 um thick. How thick is your film? For thick films, extended bakes and additional steps are required in order to get consistent results.

 

For removing the SU8 from your photomask – soaking in developer will work. Soaking in acetone also works. I find that soaking in Remover PG works best.

 

Best,

Tom

CNF

 

From: labnetwork <labnetwork-bounces at mtl.mit.edu> On Behalf Of Chang, Long
Sent: Monday, June 10, 2024 9:52 AM
To: Zhichao Wang <zhichaow at udel.edu>
Cc: Fab Network <labnetwork at mtl.mit.edu>
Subject: Re: [labnetwork] Photomask sticks to SU8

 

Thanks everyone. I got the mask mostly clean with SU8 developer. Can’t wait to try again with more baking. Anyone has tips for easy and repeatable edge bead removal? I’m thinking about using a Q-tip dipped in acetone while the wafer is spinning at 500 rpm. 

 

Long Chang

UH Nanofabrication Facility

Houston, TX

lvchang at central.uh.edu <mailto:lvchang at central.uh.edu> 

 

 





On Jun 10, 2024, at 8:25 AM, Zhichao Wang <zhichaow at udel.edu <mailto:zhichaow at udel.edu> > wrote:

 

Hi Long,  

 

We use 10min at 65C and 30min at 95C for thick SU-8 pre-bake. One of our users leaves the pre-baked wafer on a flat surface overnight and runs the exposure the next day, it seems like the film height uniformity can be slightly improved.

 

Best, 

 

On Sat, Jun 8, 2024 at 10:46 AM Howard Northfield <Howard.Northfield at uottawa.ca <mailto:Howard.Northfield at uottawa.ca> > wrote:

 

Bake it longer:

(rt to 65°C at 200°C/min)+(10min at 65°C)+(65°C to 95°C at 200°C/min)+(30min at 95°C)+(95°C to rt)

 

Clean the mask as you would develop; in a bath of SU-8 developer and spray rinse, followed by IPA bath and rinse.

 

 

 

Howard Northfield

Research Associate

Advanced Research Complex (ARC)

University of Ottawa

  _____  

From: labnetwork <labnetwork-bounces at mtl.mit.edu <mailto:labnetwork-bounces at mtl.mit.edu> > on behalf of Chang, Long <lvchang at Central.UH.EDU <mailto:lvchang at Central.UH.EDU> >
Sent: Friday, June 7, 2024 5:50 PM
To: Fab Network <labnetwork at mtl.mit.edu <mailto:labnetwork at mtl.mit.edu> >
Subject: [labnetwork] Photomask sticks to SU8 

 

Attention : courriel externe | external email

Hello, 

 

I just used Quartz Cr photomask for the first time with SU8 3050 and the SU8 stuck to the photomask after exposure, see photo. How can I prevent SU8 from sticking to my mask? How should I clean the mask?

 

Thanks,

Long Chang

UH Nanofabrication Facility

Houston, TX

lvchang at central.uh.edu <mailto:lvchang at central.uh.edu> 

<Screen Shot 2024-06-07 at 4.48.32 PM.png>

 

 

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-- 



Zhichao "Chao" Wang, Ph.D.

Lithography Engineer

UDNF

University of Delaware

Pronouns: He/Him/His

------------------------

Office Number：(302) 831-4839

221 Academy St.，RM170

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