San Francisco, CA--Jenoptik has expanded its process capabilities in single-crystal calcium fluoride (CaF2) for applications in the semiconductor market. For example, the company now produces a high-efficiency CaF2 Gaussian diffuser (see figure above) that can homogenize the beams of deep-UV excimer lasers such as the 193 nm argon fluoride (ArF) laser and the 248 nm krypton fluoride (KrF) laser.
Due to its high transparency and excellent lifetime stability, CaF2 is the material of choice for optics for excimer lasers used in the lithography market, as well as other high-power applications in the deep UV.
Diffractive, refractive, arrays, and diffusers
Jenoptik's complete product range of CaF2 micro-optics includes diffractive and refractive components such as Gaussian homogenizers, refractive fly's-eye homogenizers, diffractive lenses, lens arrays for fill-factor enhancement, and diffractive optical elements for mask inspection and illumination.
The refractive homogenizers and fly's-eye lens arrays can be designed with rectangular apertures, reducing the number of required elements to homogenize an anamorphic or rectangular field; and with substrates from 75 to 150 mm diameter and thicknesses from 0.5 to 6 mm thick.
(One of the many difficult tasks in the design of semiconductor-lithography systems is getting the illumination field at the image plane to be uniform. Doing this for high-intensity ArF-laser light is especially difficult, due to the ability of light at 193 nm to degrade optical materials. Jenoptik's components are designed specifically for these purposes. Some notes specific to the CaF2 Gaussian homogenizers: clear-aperture diameter, 5 to 50 mm; laser wavelengths, 170 to 248 nm; antireflection-coated efficiencies about 98%; available output divergences 5 to 80 mrad.)
The full range of Jenoptik's custom micro-optics is being presented at Semicon West 2010 (San Francisco, CA, from July 13 to 15, 2010; South Hall, Booth 2413).