Exciplex laser sources

At the heart of dry ArF lithography lies an exposure tool equipped with ArF exciplex laser source (emitting 193-nm wavelength photons). The insertion of ArF (193-nm) lithography into production was originally expected to take place in... 

The study of short lived excited states is limited by the low concentra- lions in which they are created on excitation with normal light sources. The use of high intensity sources such as flash lamps with suitable flashing rates and laser sources have been helpful in this respect. Triplet-triplet absorption, absorption by excited singlet state to higher singlet state and Absorption by exciplexes (Section 6.6.1) can be effectively observed by sequential biphotonic processes. 

Excimer laser A source of pulsed coherent radiation obtained from an exciplex. The proper name should be exciplex laser. Typical lasing species are noble gas hahdes (XeCl, KrF, etc.) emitting in the UV domain. 

Finally, electrons have been generated with nanosecond pulses from the KrF exciplex laser at 248 nm via photodetachment of OH and Cl in aqueous and methanol solutions, and could be via one-photon photoionization in liquids with the ArF laser at 193 nm, and via one and two-photon processes in aqueous naphthol and naphtholate with nanosecond pulsed nitrogen lasers at 337 nm. With the improved fluxes and short pulses now available from gain modulation techniques applied to the TEA exciplex lasers, semiconductor lasers and F-center lasers, they may prove to be convenient sources for future studies of electron relaxation and transfer processes from the ultraviolet to infrared region. 

The 1980s and 1990s saw the development of lithographic exposure sources such as KrF and ArF exciplex lasers. Today, the majority of advanced IC circuits are fabricated with these laser-based exposure tools. 

Examples of the application of exciplexes in hthography include KrF and ArF exciplex laser light sources for 248 nm and 193 nm hthographies, respectively. 

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