I have been etching my own boards as part of my hobby interest into electronics, and I can't help but wonder how exactly is the typical printed circuit board manufactured? Unfortunately, details on the process are extremely scarce online.
I am aware that a similar question already exists, but it doesn't really explain anything at all and the answer to the question hinges on a youtube video that has since been removed.
I have been trying to piece together the process from information available online and from my own experience, with my current assumption (about single and double sided boards) being the following:
- Hole drilling for holes, leads and vias on the bare dielectric substrate (e.g. FR4) followed by cleaning.
- Activation for electroplating (applying a thin conductive layer) and rinsing.
- Copper electroplating and rinsing.
- Surface polising and cleaning.
- Photoresist application, UV exposure and photoresist development (removal of either exposed or unexposed resist, depending on chemicals used).
- Copper etching, rinsing and photoresist removal.
- Solder mask application, UV exposure, development (removal of either exposed or unexposed solder mask, depending on chemicals used) and curing.
- Optional tin and/or gold plating of exposed copper followed by cleaning.
- Silkscreen printing, ink curing.
Is the order of steps at all correct? What solvents are used for cleaning? What chemicals are used for surface activation for electroplating? Which electrolytes are used for electroplating? Which etching chemicals are employed? Is the solder mask and photoresist applied as a dry film or as an UV curable ink, or is a photolithography technique used at all?
Yeah, I'm curious about everything.