[labnetwork] Heidelberg MLA150 SU-8 Exposure Dose

[Nam Soo Kim]

Hi Dave.
We also have similar behavior with SU-8 on the MLA150, using 1200mJ/cm2.
Using the high aspect ratio mode also increases the required dosage.
Hope this helps.
Nam

On Fri, Jun 23, 2023 at 7:53 AM Hitesh Kamble <hit.kamble at gmail.com> wrote:

> Hello Dave,
> I do not know on which material you are coating and expose but certainly
> it behaves this way because of process conditions and energy absorption
> while exposure (down the line you need to tune parameters and understand UV
> penetration).
>
> Again if it is pre-diluted or diluted with T-thinner, store conditions and
> expiry matters.
>
>
> Regards,
> Hitesh
>
>
>
> On Fri, 23 Jun 2023 at 1:57 AM Hollingshead, Dave <hollingshead.19 at osu.edu>
> wrote:
>
>> Dear Labnetwork,
>>
>>
>>
>> We have found that exposure of SU-8 on our MLA150 tool (using the 375nm
>> laser) seems to require very high doses. Even thin ~500nm thick films
>> (using SU-8 2000.5) have required doses on the order of 1200mJ/cm2 to
>> fully expose. This is 15-20x the recommended dosage from both the datasheet
>> and what we estimate is the exposure dose used on our filtered contact
>> aligners. Thicker films follow the same trend, but not necessarily in a
>> linear fashion (5µm films require ~2000mJ/cm2).
>>
>>
>>
>> I am sure the bump from 365nm to 375nm plays a role, but the magnitude of
>> the change seems excessive. FWIW, our other negative resists (eg. nLOF2020)
>> seem to expose properly at reasonable doses.
>>
>>
>>
>> Has anyone else experienced this? Does anyone have an explanation or any
>> processing suggestions for using SU-8 with an MLA?
>>
>>
>>
>> Thanks,
>>
>> -Dave
>>
>> *Dave Hollingshead*
>> Manager, Research Operations
>>
>> *The Ohio State University*
>> Nanotech West Labs
>> Suite 100, 1381 Kinnear Rd, Columbus, OH 43212
>> <https://www.google.com/maps/search/1381+Kinnear+Rd,+Columbus,+OH+43212+%0D%0A614?entry=gmail&source=g>
>> 614
>> <https://www.google.com/maps/search/1381+Kinnear+Rd,+Columbus,+OH+43212+%0D%0A614?entry=gmail&source=g>.292.1355
>> Office
>> hollingshead.19 at osu.edu / nanotech.osu.edu
>>
>> Pronouns: he/him/his
>>
>>
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