This study deals with the manufacture of so-called Fly-eye mirror in EUV lithography by means of an ultraprecision 5-axis control milling technology. It is extremely difficult to manufacture a highly accurate Fly-eye mirror by conventional methods such as photolithography, mechanical cutting by a lathe, etc. since it is composed of 500 circular arc mirror elements of 15 mm in length and 1 mm in width having a spherical surface of 295 mm in radius, and there are minute steps among them. In order to manufacture Fly-eye mirror with accuracy and efficiency, the study proposes a new machining method to manufacture spherical surface with any radius by employing a rotational single-crystal diamond tool with cutting edge angle of 90 degree. Oxygen-free copper was machined by this method. The machined workpiece shows smooth spherical surface and sharp steps among them without any burrs. It is found that the proposed method has the potential of producing the Fly-eye mirror.

Date Published: 1 July 2002
PDF: 8 pages
Proc. SPIE 4688, Emerging Lithographic Technologies VI, (1 July 2002); doi: 10.1117/12.472341

Published in SPIE Proceedings Vol. 4688:
Emerging Lithographic Technologies VI
Roxann L. Engelstad, Editor(s)