1 September 2003 Fabrication of a complex-shaped mirror for an extreme ultraviolet lithography illumination system
Author Affiliations +
We propose and discuss several fabrication processes for a complex-shaped mirror, which is a fly-eye mirror, used in an extreme ultraviolet lithography (EUVL) illumination system. The mirror has a complex reflective surface consisting of many concave mirror elements that are sections of a sphere; the top of each element is arc shaped. In the present study, we focus on one process in which all elements are fabricated individually and then arranged side-by-side to form the mirror. Thus, as the first step in this process, we fabricate the arc-shaped elements made of invar with electroless nickel plating. The resultant reflective surfaces have a peak-to-valley (PV) surface accuracy of 0.31 μm. The surfaces have the rms roughnesses of about 0.23 and 0.35 nm in areas of 110×140 μm and 1×1 μm, respectively. The slope accuracies of the surfaces relative to the bottom surfaces are –166 and 43 arc-sec in the y and x directions, respectively. Thus, the mirror elements for the fly-eye mirror can be fabricated very accurately with smooth surfaces, although the mirror elements have a special shape compared to that of general optics.
© (2003) Society of Photo-Optical Instrumentation Engineers (SPIE)
Hideo Takino, Hideo Takino, Teruki Kobayashi, Teruki Kobayashi, Norio Shibata, Norio Shibata, Masaaki Kuki, Masaaki Kuki, Akinori Itoh, Akinori Itoh, Hideki Komatsuda, Hideki Komatsuda, } "Fabrication of a complex-shaped mirror for an extreme ultraviolet lithography illumination system," Optical Engineering 42(9), (1 September 2003). https://doi.org/10.1117/1.1591797 . Submission:

Back to Top