2. What is an Excimer Laser

An excimer laser is an ultraviolet (UV) laser that uses a compound of noble gases, halogen, etc. as its laser medium, typical examples being ArF excimer lasers (wavelength of 193 nm), KrF excimer lasers (wavelength of 248 nm), XeCl excimer lasers (wavelength of 308 nm), and XeF excimer lasers (wavelength of 351 nm).
Excimer lasers have the characteristics of being able to oscillate at an exceptionally high efficiency for lasers in the ultraviolet range and enabling comparatively compact hardware, and are applied in a variety of fields such as industry and medicine (vision correction surgery such as LASIK).

Examples of excimer laser application
The high photon energy and extremely high peak power of the ultraviolet light emitted by excimer lasers are very attractive, and applied research is being carried out in a variety of fields to see whether this strong light can be utilized. For example, there are marking of materials that cannot be marked by CO2 lasers or YAG lasers, aberration processing of macromolecular films, semiconductor thin films, etc., surface reforming of resins such as Teflon etc., semiconductor manufacturing processes such as doping, deposition, and hole processing for TSV.
One of the most successful examples among these is as a light source for lithography in semiconductor fabrication. For details, go here.
Also, together with the increase in definition of liquid crystals in recent years, laser annealing for liquid crystal manufacture has been attracting attention. This is an indispensable process in the manufacture of polycrystalline low temperature poly-silicon (LTPS).