Focusing electrode for cathode arrangement, electron gun, and lithography system comprising such electron gun

摘要

The invention relates to a cathode arrangement comprising:
a thermionic cathode comprising an emission portion provided with an emission surface for emitting electrons, and a reservoir for holding a material, wherein the material, when heated, releases work function lowering particles that diffuse towards the emission portion and emanate at the emission surface at a first evaporation rate;a focusing electrode comprising a focusing surface for focusing the electrons emitted from the emission surface of the cathode; andan adjustable heat source configured for keeping the focusing surface at a temperature at which accumulation of work function lowering particles on the focusing surface is prevented.

主权项

1. Focusing electrode, comprising:
a cylindrical shell defining a cavity for accommodating a cathode body, and a front cover provided with a circular electron transmission aperture and a focusing surface,wherein a heat trapping surface is provided on an inner surface of the cylindrical shell, the heat trapping surface being arranged for receiving heat radiation emitted by the cathode body during use,wherein the front cover further comprises an inner electrode surface, arranged for supporting the cathode body,wherein the cylindrical shell comprises angular interspacings for accommodating a confining arrangement for confining the focusing electrode and/or the cathode body with respect to a support structure.