Repairing amplitude defects in multilayer-coated extreme-ultraviolet lithography reticles by use of a focused ion beam.
We present a method for repairing defects near the top surfaces of multilayer coatings in general and specifically on extreme-ultraviolet lithography mask blanks. Milling away the defect and a surrounding region of the multilayer by use of a focused ion beam can repair both the reflectivity and the phase of the reflected light in the vicinity of such a defect. We describe the conditions under which the repaired region will not itself be a defect and experimentally demonstrate the feasibility of this multilayer repair technique. The results described are also applicable to understanding and controlling the optical effects of ion-induced multilayer erosion.
Barty
Anton
A
Lawrence Livermore National Laboratory, Livermore, California 94550, USA. barty2@llnl.gov
Hau-Riege
Stefan
S
Stearns
Dan
D
Clift
Miles
M
Mirkarimi
Paul
P
Gullikson
Eric
E
Chapman
Henry
H
Sweeney
Don
D