[Libre-silicon-devel] Uncertainty: DMD chips and 420nm

[Dilek Isik Akcakaya]

Hi All, David,

I see that you selected a greyscale PR for photolithography, it uses TMAH based developers I do not know the range of other developers it can make use of. Can we list them? This series of PR are foreign to me. I used Shipley, AZ etc. You must not buy and use TMAH based developers at home labs due to safety reasons it is extremely toxic! Second chemical I will beware of is HF in the same way in a home environment.

Second,
What is the reason for going for a grayscale PR and not a regular one?

Third,
The UV range depends on the PR we will be using, the smaller the wavelength, more precise will be the features if we can use the right optical system of course (De Broglies eqn.). Because I am new to the project please let me know why we decide don this set of PRs.

As per UV range of the DLP once again this depends on the PRs to be used and because DLP works by reflection, you may loose power due to reflectance, absorption and other optical phenomena therefore I think we need to be as precise as possible with our selections.

Let me point out:
The rail system precision+ DLP resolution (not the pixel size)
as an end result of multiple selections such as good focus etc+ PR thickness+ Development time + Light source wavelength + overlay reproducibility = approximately OUR RESOLUTION.

With current selections are we sure we will be able to reproduce 50 um features and have a good overlay if we need a second layer alignment on top?

Thank you,




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‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

David Lanzendörfer <leviathan at libresilicon.com> 11 Ağustos 2021 Çarşamba saat 12:51 tarihinde yazdı:

> Hi Dilek, hi list
>
> Sorry again about the downtime of the infrastructure during the day yesterday.
>
> The infrastructure of the data center I've got my rack server in was down.
>
> Now to the topic:
>
> I've started writing down the BOM and I'm not sure whether 420 nm UV already
>
> has too much energy, although the data sheet of the DMD chip says it's ok to
>
> be operated until 400nm.
>
> Here's the BOM:
>
> https://redmine.libresilicon.com/projects/maskless-lithography/wiki
>
> It would be cool to get feedback on that from Texas Instruments.
>
> Cheers
>
> David
>
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