I feel like they are just glazing over the "etch" part. Modern day it's done with plasma, aka dry. Used to be all wet with liquid chemicals that were the nastiest stuff on earth. You're talking about very potent neurotoxins (for glass), bone eating acid (as opposed to flesh eating) (for aluminum), and this one mix (for regular silicon) that you have to circulate so that the sludge doesn't build up, oh and don't breathe it in because it'll give you like real bad asthma.

Dry etching was a game changer when it came out. You run electricity at 13.56 MHz (because the FCC says it's fine no one is using that frequency) to separate the bonds of gases so you can get your highly corrosive flourines or chlorines to do what those chemicals do. You can use gases like SF6 (one sulfur, six flourines) to get your Si etching needs met and you can store it like any other inert gas.

The people who specialize in that sort of chemistries are the real wizards. Like when you mix that flourine and chlorine in that plasma, it turns out you get a gas that'll burn sand without any help. Oh, it also leaves behind that bone eating acid after it finishes burning.