Maskless photolitography using a pico projector [buildlog]

General
1

most urgent info is at http://wiki.idiot.io/index.php?title=Picolito

following is a draft that was accidently submitted after lingering for 2 weeks waiting for my more then 2 images/links in a post new user ban lifts.

hey, ill use this here space as a log for my build.
hope to leech some knowledge from optical heads and such.

intro

so after oogeling at samZellof and jeriellsworth work on home semiconductor chip fabs i wanted some of that. currntly not intrested in micro work, i want to use some of the ideas in idiot.io work. mostly 10mil+ board designs

progress

3/4/2018

i had an LCoS type pico projector with me so i started toying with it, looking at possible line pitch and native resolution.

also started collecting equipment.

  • 10x7.5cm FR4 pcb with photoresist coating
  • Sodium hydroxide - for developing
  • etchant solution - i was feeilng lucky

waiting for night to come so i can do the lithography i read a bit on the aaxa projector i had in hand.

aaxa pico HD spec pic

  • focus - at 10x6cm was ok just the sizes we were dealing with
  • pitch- line seperation issues, with vertical resolution, some lines where missing, or faded. (video). its best seen with a grid pattern, but i didn’t take suh photo it seems. really hard to capture this as the LCoS is strobing between the 3 LEDs and the angle of projection makes shadows.
  • contrast- spec is 1:2000, it looks realy good. but cant say before a real exposure test
  • UV ouput - it has none, there is a UV filter that needs to be removed, also dichroic mirrors on each LED, tuned to “visible spectrum”. most research out there is regarding DLP type of projectors, they allow much more light (and single source at that), see here

4/4/2018

during a teardown stream with eladorbach, Elad pointed me to TI “LightCrafter” evaluation boards for DLP pico projectors.

lightcrafter 2000 EVM- 100$ (link)
beagleboard green/black - 60-90$ (pic)

whats next

giving up on complete disassembly of the LCoS projector for now.

ordered and digging for information on the lightcrafter2000 board
espcially on the LEDs they use. see if they have enough UV in them, and if not, whats the LED package they use and how to replace it with a ~400nm one.

Links