US 7,489,386 B2
System and method for projecting a pattern from a mask onto a substrate
Frank-Michael Kamm, Dresden (Germany); and Rainer Pforr, Weixdorf (Germany)
Assigned to Qimonda AG, Munich (Germany)
Filed on May 03, 2007, as Appl. No. 11/743,870.
Claims priority of application No. 10 2006 022 352 (DE), filed on May 12, 2006.
Prior Publication US 2007/0263198 A1, Nov. 15, 2007
Int. Cl. G03B 27/54 (2006.01); G03B 27/52 (2006.01)
U.S. Cl. 355—67  [355/55] 26 Claims
OG exemplary drawing
 
1. A system for projecting a pattern from a mask onto a substrate comprising:
a radiation source to emit a light beam in the extreme ultraviolet wavelength range;
a mask to reflect a patterned light beam and comprising absorbent and reflective structure elements arranged to form the pattern;
a collector mirror and an illumination optical system forming a first part of a beam path to direct the light beam onto the mask;
a projection optical system comprising an arrangement of reflective mirrors forming a second part of the beam path to focus the patterned light beam from the mask onto a substrate and image the pattern on the substrate; and
an optical element arranged in the beam path and located a distance from any conjugate plane associated with the mask, the optical element comprising at least two regions having different degrees of reflection or transmission, wherein a first region is assigned to a first position on at least one of the mask and the collector mirror and a second region is assigned to a second different position on at least one of the mask and the collector mirror in accordance with the beam path.