Can someone explain why neon is critical for "lasers used in chip manufacturing" ? I don't think they'd be using He-Ne lasers, and if they are I would think those could be replaced fairly easily with solid-state lasers.
Somewhat counterintuitively, the primary gas species used in excimer lasers are noble gasses. A typical gas mix for a 193nm excimer laser would be ~97% neon and just a few percent of the actual argon/fluorine excimer mix. [1]
Since you mentioned them -- as hard as it may be to believe -- HeNe lasers are only just beginning to be phased out in the semi industry in the somewhat esoteric use case of precision position measurement using interferometry. The output wavelength of a HeNe lase is extremely stable--with a simple feedback loop on the cavity length (ie, temperature) a HeNe laser is essentially an atomic clock locked to the 473.612248 THz 5s2 → 3p HeNe line. Interferometers built around such systems can accurately measure sub-nanometer displacements and are able to achieve a lifetime absolute stability of better than 10ppb--comparable to a rubidium atomic clock! [2]
Deep-ultraviolet excimer lasers, I think (?). Not a domain expert!
- "Excimer laser gas mixtures are a combination of rare gases (argon, krypton, xenon, or neon) and halogen gases (fluorine or chlorine). The mixture of gases determines the wavelength of DUV light produced. Argon+fluorine+neon (193nm) and Krypton+fluorine+neon (248nm) are the two most common mixtures used. In terms of volume; neon makes up approximately 96–97.5% of the mixture."
There could very well be HeNe lasers used as an interferometric length standard in lithography equipment. There are some solid-state lasers that could substitute for that role, such as NPRO lasers, but they're much more expensive and not widely produced.
