Kris\Slyka
@slyka@pawb.fun  ·  activity timestamp 3 weeks ago

wheeee! I've successfully made a glass PCB! 0.1mm copper foil laminated onto a microscope slide using two component epoxy and a hot roller laminator, coated with cheap aliexpress dry film photo resist and etched in copper chloride.

turns out that most of my struggles during etching came from my bad exposure setup. The light source was way too diffuse and I way over exposed the photo resist. Going from 7.5 minute exposures down to 20 seconds really helped and switching from a very diffuse UV exposure box to a UV spot light mounted around 50cm away finally got me to an acceptable result.

Of course the one that ended up working was on my ugliest piece of copper on glass laminate but whatever. It finally works!

#diypcb #electronics

Three tiny copper on glass PCBs made on microscope slides, getting more crisp, less blobby and less oxidized going from left to right. The one on the left has tons of bridges between traces, most of them are just kinda melted together. The middle one is a little better and the right most one is a perfectly serviceable PCB. It's got some flaws from bubbles under the photo resist, but nothing that would keep it from working
Three tiny copper on glass PCBs made on microscope slides, getting more crisp, less blobby and less oxidized going from left to right. The one on the left has tons of bridges between traces, most of them are just kinda melted together. The middle one is a little better and the right most one is a perfectly serviceable PCB. It's got some flaws from bubbles under the photo resist, but nothing that would keep it from working
Three tiny copper on glass PCBs made on microscope slides, getting more crisp, less blobby and less oxidized going from left to right. The one on the left has tons of bridges between traces, most of them are just kinda melted together. The middle one is a little better and the right most one is a perfectly serviceable PCB. It's got some flaws from bubbles under the photo resist, but nothing that would keep it from working
Kris\Slyka
@slyka@pawb.fun  ·  activity timestamp 2 weeks ago

there are also a bunch of other small defects, probably caused by small bubbles or other defects in the photoresist. luckily only one of them seems to have led to a broken trace which I'll have to fix later.

oh yeah, also, all the brown stains all over the PCB? don't just dump dry NaOH into the resist stripper bath when it's starting to run out. getting it onto the PCB will fuck up the copper surface…

#electronics #diypcb
Kris\Slyka
@slyka@pawb.fun  ·  activity timestamp 2 weeks ago

last but not least, a test fit with one of the chips. it fits! Wheeeeee!

#electronics #diypcb
Kris\Slyka
@slyka@pawb.fun  ·  activity timestamp 2 weeks ago

here's some closeups of the small bridges. the very thin ones tend to be easier to see from the back. good thing glass is see through!
I'm still struggling to completely avoid these, but I think my track spacing might still be a little on the low side for this thick copper layer. maybe I also just need to etch for longer, but I'm worried about excessive under-etch…
luckily the small bridges are very easy to clean up with a scalpel.

#electronics #diypcb
Kris\Slyka
@slyka@pawb.fun  ·  activity timestamp 2 weeks ago

there are also a bunch of other small defects, probably caused by small bubbles or other defects in the photoresist. luckily only one of them seems to have led to a broken trace which I'll have to fix later.

oh yeah, also, all the brown stains all over the PCB? don't just dump dry NaOH into the resist stripper bath when it's starting to run out. getting it onto the PCB will fuck up the copper surface…

#electronics #diypcb
Kris\Slyka
@slyka@pawb.fun  ·  activity timestamp 2 weeks ago

put today's tiny glass PCB and put it under the microscope to get some close up shots! it's really cool to see just how thick that 0.1mm copper is! there are still tons of flaws that become very apparently once you zoom in, some small bridges and some thin spots and breaks in in some traces. once you get up close it all looks very… organic.

#electronics #diypcb
Kris\Slyka
@slyka@pawb.fun  ·  activity timestamp 2 weeks ago

here's some closeups of the small bridges. the very thin ones tend to be easier to see from the back. good thing glass is see through!
I'm still struggling to completely avoid these, but I think my track spacing might still be a little on the low side for this thick copper layer. maybe I also just need to etch for longer, but I'm worried about excessive under-etch…
luckily the small bridges are very easy to clean up with a scalpel.

#electronics #diypcb