The joint specification projected in-band EUV power requirements at the intermediate focus will rise beyond 185W 2%-bw to maintain the necessary 80-100WPH throughput for economic viability. New improvements in photon efficiency
and mask illumination are needed to reduce reflections and power demand, as well as improving source spatial
uniformity. In 2006, Starfire Industries presented a microdischarge plasma light source concept for consideration as a
potential HVM solution for high-power spatial and temporal multiplexing. Using a distributed array architecture,
thermal and particle loadings become manageable when spread over 100s to 1000s of discrete units allowing power
scalability. In addition, a key tenant is the potential for novel collection and illumination geometries that could simulate
Kohler and pupil fill effects found in conventional fly's-eye mirror systems; thus leading to a reduction in optical
elements and a factor of >5x increase in total throughput. A top-level illuminator optical design based on the
microsource array technology is presented, as well as thoughts on illumination efficiency, reticle uniformity, partial
coherence and uniformity of the pupil fill for a realistic EUV source array. In addition, experimental data from xenonbased
sources will be presented with a suite of plasma and optical diagnostic instruments, including conversion
The selection of optical glasses by the lens designer should, by all rights, be a scientifically sound and straightforward task. Unfortunately, this is not the case. The designer is faced with a myriad of potential glass types to use, and in reality, the task is both a science as well as an art. Part of the problem lies in the fact that while the basic optical parameters, namely the refractive index and the Abbe number or V-number are readily accessible in the catalogue or on the standard glass map, many other attributes regarding the specific glasses such as physical properties, resistance to stain or bubbles, and many other parameters, are somewhat buried away on the individual data sheets for each glass. The designer is therefore faced quite often with the dilemma of which glass to select. This becomes particularly challenging when the designer has varied the refractive index and the Abbe number in his or her optimization, and the glass has settled into a moderately unpopulated region of the glass map. And to further complicate the task, the designer simply does not have the time or the patience to labor over hundreds of glass data sheets. Of the three major glass manufacturers (Schott, Ohara, and Hoya) Schott's glass map presents the user with glasses printed in red and glasses printed in black. The red glasses are "preferred," which means that the glasses are more readily available. It does not mean that the glasses are lower in cost, have better stain or bubble characteristics, or are easier to work. It simply means that they are more likely to be on the shelf. This may not be an optimum criteria from a producibility or a cost standpoint. The Hoya glass map presents the designer with glasses that are shown as either big red dots, big yellow dots, smaller green dots, very small purple dots, and lastly, very small blue dots. The large red dot glasses are "melted monthly in a large mass," the large yellow dot glasses are "melted monthly in a medium mass," and eventually the very small blue dot glasses are "melted rarely and may be discontinued in the future." In addition, the Hoya glass map adds the cost relative to that of BK7 in any of the large dot glasses. This is a very useful form of glass map; however, it still does not contain any information whatsoever regarding stain, bubbles, physical characteristics, or others. We decided it was time to come up with a comprehensive visually-based data base of optical glasses, and this paper will describe the GlassView program.
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