Apparatus for and method of active cleaning of EUV optic with RF plasma field
AssigneeASML Netherlands B.V.
InventorAlexander I. Ershov
Life of this patent
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Abstract
Apparatus for and method of cleaning an electrically conductive surface of an optical element in a system for generating extreme ultraviolet radiation in which electrically conductive surface is used as an electrode for generating a plasma which cleans the surface.
Claims14
Apparatus comprising:
- an extreme ultraviolet light optical element having an electrically conductive surface having an obscuration;
- and
- an electrically conductive member arranged adjacent an obscuration region of the electrically conductive surface and electrically coupled to the electrically conductive surface,
- the electrically conductive surface and the electrically conductive member being arranged with respect to each other such that a plasma is produced when RF power is supplied to the electrically conductive member, the plasma being capable of removing contaminants from at least a portion of the electrically conductive surface.
Apparatus comprising:
- an electrically conductive mirror surface of an extreme ultraviolet radiation optical element, the mirror surface being circular and having a central aperture;
- and
- an electrode plate arranged adjacent to and electrically coupled to an adjacent portion of the mirror surface, the electrode plate conforming to a shape of an adjacent portion of the mirror surface and spanning the mirror surface except for the central aperture, the adjacent portion being an obscuration region of the mirror surface.
A module for producing extreme ultraviolet radiation, the module comprising:
- an RF driver circuit;
- an RF electrode comprising an electrically conductive surface of a collector mirror arranged to focus radiation from an extreme ultraviolet light producing plasma;
- and
- an electrically conductive member arranged in proximity to an obscuration portion of the electrically conductive surface, the electrically conductive member being electrically connected to the RF driver circuit and arranged to couple RF energy into the electrically conductive surface.
A method of cleaning an electrically conductive mirror surface in an extreme ultraviolet light source, an electrically conductive member being positioned adjacent an obscuration portion of the electrically conductive mirror surface, the method comprising the steps of:
- providing RF power to the electrically conductive member;
- and
- coupling the RF power from the electrically conductive member to the electrically conductive mirror surface to produce a capacitively coupled RF plasma at the electrically conductive mirror surface to clean the electrically conductive mirror surface.
Apparatus comprising:
- an illumination system for producing a radiation beam;
- a support structure for supporting a patterning device in a path of the radiation beam, the patterning device imparting a pattern to the radiation beam;
- a substrate table for supporting a substrate;
- and
- a projection system adapted to project the pattern onto the substrate,
- the illumination system comprising an extreme ultraviolet light optical element having an electrically conductive surface and an electrically conductive member arranged adjacent an obscuration region of the electrically conductive surface and electrically coupled to the electrically conductive surface, the electrically conductive surface and the electrically conductive member being arranged with respect to each other such that a plasma is produced when RF power is supplied to the electrically conductive member, the plasma being capable of removing contaminants from at least a portion of the electrically conductive surface.
Dependencies are inferred from the claim text.