Patent ID: 6326632
Filing Date: 2001-12-04
Classification: B82Y,G03F,H01J

Abstract:
A particle-optical imaging system for lithography comprising along its optical axis:an illuminating system having a particle source and a first electro-static lens arrangement for producing a particle beam chosen from a substantially telecentric and substantially homocentric particle beam;a mask holding device for positioning a mask foil in the beam path of the particle beam, the mask foil being provided with a structure in the form of a plurality of sites that are transparent to the particle beam; anda projection system having a second electro-static lens arrangement for imaging the structure of the mask foil by means of the particle beam on a substrate plane,wherein the second lens arrangement comprises at least one post-mask electrode on a side of the second lens arrangement facing the mask holding device, the at least one post-mask electrode being in the form of an annular electrode, and wherein different electrostatic potentials can be applied to the post-mask electrode and to the mask foil, the mask foil functioning as a control grid electrode, and the mask foil together with the at least one post-mask electrode forming a control grid lens having negative refracting power,and further wherein the first lens arrangement comprises at least one pre-mask, electrode on a side of the first lens arrangement facing the mask holding device, at least one pre-mask electrode being in the form of an annular electrode, and wherein different electro-static potentials can be applied to the pre-mask electrode and to the mask foil, the at least one pre-mask electrode together with the mask foil forming a control grid lens having a negative refracting power.