Two types of linear multilayer gratings have been investigated with special attention on the influence of the fabrication method on performance. Rh/C and Mo/Si systems have been realized for use above the carbon K-edge at 43.6 A and the silicon L3 edge at 125 A, respectively. We analyzed in detail the performance of the multilayer coatings in relation with their structural behavior. Mo/Si amplitude gratings were manufactured by suppressing the soft X-ray reflectivity of the multilayer mirror in selective areas with gold coating and lift off process. This method provides a well-defined 3 micron period Au grating. The soft X-ray reflectivity of the multilayer alone reached a maximum of 45 percent at normal incidence, whereas it was measured around 12.5 percent after Au grating deposition. Up to 13 grating orders were detected in the grating scan and detector scan showing the very good quality of these structures. A more unusual method was applied to manufacture Rh/C multilayer gratings. A carbon grating was first patterned on a silicon substrate and the multilayer was deposited at the end of the process. Measured reflectivity around 60 A in conventional 0 - 20 scan shows a reduction of the performances by a factor three. This is probably due to the surface roughness of the carbon grating prior to the multilayer deposition.

Date Published: 21 January 1993
PDF: 12 pages
Proc. SPIE 1742, Multilayer and Grazing Incidence X-Ray/EUV Optics for Astronomy and Projection Lithography, (21 January 1993); doi: 10.1117/12.140580

Published in SPIE Proceedings Vol. 1742:
Multilayer and Grazing Incidence X-Ray/EUV Optics for Astronomy and Projection Lithography
Richard B. Hoover; Arthur B. C. Walker II, Editor(s)