To become a PCB designer, what must I study/learn?
There is an adage about learning things.
One must spend 10,000 hours practicing something before learning to master it.
I do not believe that there are any specialist courses for this, but decades ago, there were courses in the USA. The focus of these was based on the assumption that it was a drafting job.
Here are some hints to accelerate learning:
Practice doing single sided designs, and minimising the number of links you need. After some practice you will amaze yourself how much routing you can do without needing any links at all. This skill will make laying out large N layer boards very easy. Remember the adage: vias are not your friend - they are your enemy.
Remember that minimum track widths and via sizes are the limit of what your vendor can do. Use these limits sparingly, not by default. Unless you are routing fine pitch BGAs, you rarely need very tiny (and expensive) vias. Even then, simply create different design rules for the region under BGAs.
Ignore adhoc rules. For example “blind and buried vias are to be avoided at all costs”. Once upon a time these were difficult and expensive. Blind vias can be a problem, but they have great RF properties that can be very useful. Buried vias, on the other hand are not particularly expensive, and are extremely useful under a BGA to free up space to put decoupling caps on the bottom of the board. And those decouplers and minimising trace lengths to them, are essential.
Develop close friendships with the people who fabricate the boards, and those who assemble them. When they are confident enough in their relationship with you, they will start giving you critical feedback, ie telling you what you are doing wrong. Only then can you start to learn from them.
Avoid “experts”, who say they are too busy to explain things to you. Such people are rarely “experts”. They are people who have no idea what they are doing, and don’t want anyone to know.
Listen to anything, that any experienced person is willing to tell you - try their suggestions, and using feedback from (4) either adopt, adopt in a qualified way, or reject their advice.
Learn about laminates. Understand parameters like Dk, dissipation factors, Tg, delamination, Zo, peel strength. Make yourself familiar with the online tools to calculate IPC2221A track widths.
Understand how CAD systems do things - dont take the veracity of their tools for granted. Altium for example cannot calculate Zo, for example, correctly, despite offering a tool that alleges that they do.
Never, ever, take a vendors’ footprint as being the definitive blueprint for a footprint. Always check the geometry back against the IPC rules for components.
Mentor manage the free footprint library for the IPC footprint library. Mentor cannot handle rounded rectangular pads, so that library does not have rounded rectangular SMT pads. ALWAYS use rounded rectangular SMT pads. The surface tension on sharp cornered pads pulls solder to the corners of the pads.
RJ Moonk commented
IPC footprint library method, as can be seen from the tutorials, can only be used to minimize functions in which there exists an inverse matrix of other derivatives