講演情報
[9p-N103-8]Effect of Thickness graded Mo/Si multilayer Mirror on Pupil Transmission Uniformity of EUV Lithography Optics
〇(PC)Maidul Haque Sekh1, Shun Uji1, Mitsunori Toyoda1 (1.Tokyo Polytechnic University, Atsugi, Japan)
キーワード：
Semicondutor、Lithoigraphy、Thin film mirror
The distribution of mean angle of incidence on all elements of 6-mirror EUV (13.4 nm) projection system has been simulated for a fan shaped image with image numerical aperture of 0.26. The mean angle of incidence has been calculated considering 10 representative field points of the fan shaped image, by applying the optical design software, Code-V. The lateral variation of mean angle of incidence on reflective surfaces is an important concern in such systems due to limited angular band width of multilayer EUV mirrors. A 41 bi-layer Mo/Si mirror considering both (i) uniform thickness and (ii) graded thickness, has been applied as reflective surface for surface-5 and the pupil transmission map has been simulated in corresponding cases. The pupil map shows relatively poor transmittance uniformity in the range of 2.1% to 73.0 % for the uniform thickness mirror due to limited peak bandwidth. In contrast, graded thickness mirror exhibits much greater uniformity in the range of 63.2% to 74.7% in predominant area of the pupil.