Basics

This page goes over the various ways OSE (Or other interested groups) could go about Lithography, without the need to produce a seperate photomask for each project
It is similar to Injection Mold Tooling vs 3D Printing
There are a few ways this could be done at a Makerspace+ Level Scale
Mainly:
- LCD (Double Check)
- DLP (Proven)
- Laser (Proven)
- Potentially Electron Beam
The Main Applications of this Microfabrication capability would be Semiconductors, MEMS , Microfluidics , and potentially Meta-Materials (Although the latter is far more niche) (Although given the Scale of it all it would moreso be for RnD and Edge Cases/Small Batch Production for Them)

Existing Open Source Designs

They have made two so far:
A Video by the YouTube Channel "Breaking Taps" Titled "DIY Laser Lithography: Micron resolution" ( ~22 Minute Watch )
- Direct Write Laser Lithography
- 1-3 Micron Resolution ( Timecode to where they discuss this
- Mostly 3D Printed Parts + Aluminum Extrusion
- 4.5nm UV Diode Laser
- Optical Breadboard Based
- Microscope Optic at the end
- Low repeatability due to Low Rigidity, Creep, and Coefficient of Thermal Expansion
- Was moreso a proof of concept
A Video by the YouTube Channel "Breaking Taps" Titled "Electron Beam Lithography: drawing images with electrons" ( ~25 Minute Watch )
- Uses an OTS Electron Microscope and PMMA (Acrylic) Dissolved in Anisole (Also known as Methoxybenzene ) on a Silicon Wafer doped so it is electrically conductive
- ~100nm Capable, may need to be a bit above that to be reliable ( Timecode to where they discuss this )
- Also needs more tuning and a proper cleanroom / glovebox !

The Project's Playlist (~5 12 Minute Videos)
Resolution Unknown, Need to Dig and/or Ask Them
- They did make some sort of functional Metasurface Lens called a Fresnel Zone Plate so that's something!
- The diagnostic text etched above each lens also seemed quite clear, but need a number

A Video by the YouTube Channel "Sam Zeloof" Titled "Maskless Photolithography with DLP Projector - 10um Feature Sizes" ( ~23 Minute Watch )
- This is the older video where a stepper wasn't even used, just a jig to hold the wafer in place and a fixed projector
A Video by the YouTube Channel "Sam Zeloof" Titled "Maskless Photolithography Stepper for Homemade Chips" ( ~10 Minute Watch )
- Uses a projector fed into a microscope onto a xy stage (this may be a used proper device) with a vacuum chuck / Vacuum Workholding )
- Also used a camera to calibrate for projectors with non-uniform brightness pre-sending the mask image
A Video by the YouTube Channel "Sam Zeloof" Titled "Making Tiny Things with Electron Microscope - E-beam Lithography" ( ~9 Minute Watch )