An DPP EUV source is disclosed which may comprise a debris mitigation apparatus employing a
metal halogen gas producing a
metal halide from debris exiting the
plasma. The EUV source may have a debris shield that may comprise a plurality of curvilinear shield members having inner and outer surfaces connected by light passages aligned to a focal point, which shield members may be alternated with open spaces between them and may have surfaces that form a circle in one axis of rotation and an
ellipse in another. The electrodes may be supplied with a
discharge pulse shaped to produce a modest current during the axial run out phase of the
discharge and a peak occurring during the
radial compression phase of the
discharge. The
light source may comprise a
turbomolecular pump having an inlet connected to the generation chamber and operable to preferentially pump more of the source gas than the
buffer gas from the chamber. The source may comprise a tuned
electrically conductive electrode comprising: a differentially doped
ceramic material doped in a first region to at least select electrical
conductivity and in a second region at least to select
thermal conductivity. The first region may be at or near the outer surface of the
electrode structure and the
ceramic material may be SiC or
alumina and the
dopant is BN or a
metal oxide, including SiO or TiO2. The source may comprise a moveable
electrode assembly mount operative to move the electrode
assembly mount from a replacement position to an operating position, with the moveable
mount on a
bellows. The source may have a
temperature control mechanism operatively connected to the collector and operative to regulate the temperature of the respective shell members to maintain a temperature related geometry optimizing the glancing
angle of incidence reflections from the respective shell members, or a mechanical positioner to position the shell members. The shells may be biased with a
voltage. The debris shield may be fabricated using off focus
laser radiation. The
anode may be cooled with a hollow interior defining two
coolant passages or
porous metal defining the passages. The debris shield may be formed of pluralities of large, intermediate and small fins attached either to a mounting ring or hub or to each other with
interlocking tabs that provide uniform separation and strengthening and do not block any significant amount of light.