Ultraviolet (UV) lasers are in many ways ideal industrial processing tools. They offer a noncontact method of producing fine microstructures on many substances, with minimal effect on surrounding material. The most important type of high power UV laser for industrial applications is the excimer laser. Available wavelengths include 351, 308, 248, 193, and 157 nm. The largest commercially available excimer lasers generate up to 200 W stabilized average power and up to 700 mJ pulse energy at 308 nm. Nd:yttrium aluminum garnet (YAG) lasers that utilize nonlinear crystals to transform the 1.06 μm output to its third (355 nm), fourth (266 nm), or fifth (213 nm) harmonic are also an important industrial UV source. More and more diode-pumped, frequency multiplied Nd:YAG lasers greatly impact the industrial processing market. The advantage of this laser is that it is physically compact, highly reliable, and mechanically rugged. Coupled with advantages of short wavelength output, recent improvements in laser reliability, cost of ownership, and performance are enabling UV lasers to be employed in an expanding range of applications. This article will briefly review those applications and their main laser requirements, and then present the most current advances in UV laser technology which address those needs.

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Advanced deep ultraviolet (DUV) optical lithography requires reliable high repetition rate excimer lasers at low cost of ownership. We optimized all components of the laser cavity. The result is a new metal/high-density ceramic laser tube with long life discharge components. It meets the specifications of the next generation of DUV laser sources. The new laser cavity was tested in several test runs at 193 nm (ArF) and 248 nm (KrF) and demonstrated excellent gas lifetime data when compared to conventionally designed lasers. For the first time a KrF laser was successfully operated in a quasi sealed-off mode for more than 1 billion pulses. The lifetime data of narrow bandwidth lasers necessary for DUV optical lithography tools also increase significantly. A 500 Hz 6 W laser with a bandwidth of 0.9 µ m passed in a marathon test 1.1 billion pulses and the gas lifetime exceeded 200 million pulses routinely. Additionally, we operated this laser at 8 W average power and 600 Hz.

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