Not an expert, but I've always understood it as (LI5): You may have heard the effect of light is like a wave, higher frequency wave-lengths have a shorter wave

Not an expert, but I've always understood it as (LI5): You may have heard the effect of light is like a wave, higher frequency wave-lengths have a shorter wavelength, which means it can 'reach' smaller features without impacting the rest of the surroundings. Photo-lithography is done through a mask, this effectively means you get a crisper image projected onto the wafer. If you go too far into/past UV it becomes hard to deal with in terms of heat and optics from my understanding. Which is why we keep getting new $prefix-UV rather than something like X-rays (which are past UV).