Lambda Physik introduces 0.6-pm-linewidth excimer-laser source
An excimer laser with an emission linewidth of 0.6 pm (full width at half maximum) was to be introduced by Lambda Physik (Göttingen, Germany) at Semicon Japan (Dec. 3-5; Makuhari, Japan). The company claims its NovaLine LITHO/S is the narrowest-spectral-linewidth 248-nm excimer-laser source available and notes that linewidth is an especially important parameter for microlithography applications.
A narrow linewidth greatly reduces chromatic aberrations in a projection lens, allowing circuit feature sizes as small as 0.18 µm to be achieved. Chromatic aberrations are very difficult to correct in such lenses because of the limited number of materials that transmit at deep-ultraviolet wavelengths. A key factor in achieving the 0.6-pm linewidth is the use of a proprietary polarization-coupled resonator design. The design, which improves both spectral purity and laser-operating efficiency, is the product of a joint development effort between Matsushita Research Institute of Technology (Tokyo, Japan) and Lambda Physik.
