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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

Another microscope shot of some of the 1206 resistor and LED pads.

Another SOIC 14 footprint and some of the hatched ground plane.

Another shot of the same PCB, showing a footprint for a 555 timer. There is a surprising amount of dimensionality to the traces and pads.

Microscope shot of a tiny home made PCB on glass, focused on a SOIC 14 footprint. The copper layer is stained dark in some places and looks kinda… wobbly.

Kris\Slyka

@slyka@pawb.fun · 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

The same bridge, this time from the top after cleaning it up using a scalpel

Another microscope shot of a bridge shown from the back side of the PCB.

Another photo of the same thing, but this time through the glass

Microscope photograph of a small bridge between two copper traces that didn't etch away completely.

Kris\Slyka

@slyka@pawb.fun · 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

Micrograph of a break in one of the traces, probably also caused by a defect in the photoresist.

Closeup microscope photography (micrograph?) of a defect in the copper layer where a bubble in the photoresist has allowed etchant to seep under it and mess up the copper, leaving a small crater.

Kris\Slyka

@slyka@pawb.fun · 2 weeks ago

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

#electronics #diypcb

A close up of some of the legs of the chip sitting on their pads.

A small SOIC 14 chip (74HC164) places onto it's pads. It fits!

Kris\Slyka

@slyka@pawb.fun · 2 weeks ago

oh yeah, also, I used a different epoxy this time! Smooth on XTC-3D. It's meant to be used as a top coat for 3d prints but it's very nice and clear and it seems to stand up to the etching and everything even better than the cheap hardware store stuff I used before. It still comes out a little matte cause the brushed finish of the bottom of the copper impresses onto it so I might try giving the copper more of a polish before gluing.

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