Collector for EUV light source

The apparatus of claim 21, further comprising:

• the reflecting surface comprises a capping layer comprising a fourth material selected to have a sputter thickness rate that will also sustain sputtering by the second material at or below a rate that will result in a single layer of the fourth material sustaining such sputtering for greater than the selected time and to have more favorable properties when exposed to ambient or operating environments than those of the first material.

The apparatus of claim 22, further comprising:

• the reflecting surface comprises a capping layer comprising a fourth material selected to have a sputter thickness rate that will also sustain sputtering by the second material at or below a rate that will result in a single layer of the fourth material sustaining such sputtering for greater than the selected time-and to have more favorable properties when exposed to ambient or operating environments than those of the first material.

The apparatus of claim 23 further comprising:

• the reflecting surface comprises a capping layer comprising a fourth material selected to have a sputter thickness rate that will also sustain sputtering by the second material at or below a rate that will result in a single layer of the fourth material sustaining such sputtering for greater than the selected time and to have more favorable properties when exposed to ambient or operating environments than those of the first material.

The apparatus of claim 24 further comprising:

• the reflecting surface comprises a capping layer comprising a fourth material selected to have a sputter thickness rate that will also sustain sputtering by the second material at or below a rate that will result in a single layer of the fourth material sustaining such sputtering for greater than the selected time and to have more favorable properties when exposed to ambient or operating environments than those of the first material.

A multi-layer reflecting coating forming an EUV reflective surface comprising:

• an inter-diffusion barrier layer comprising a carbide selected from the group SiC, ZrC and NbC.

A multi-layer reflecting coating forming an EUV reflective surface comprising:

• an inter-diffusion barrier layer comprising a boride selected from the group ZrB2 and NbB2.

A multi-layer reflecting coating forming an EUV reflective surface comprising:

• an inter-diffusion barrier layer comprising a disilicide selected from the group ZrSi2 and NbSi2.

A multi-layer reflecting coating forming an EUV reflective surface comprising:

• an inter-diffusion barrier layer comprising a nitride selected from the group BN, ZrN, NbN, ScN and Si3N4.

A multi-layer reflecting coating forming an EUV reflective surface comprising:

• a spectral filter tuned to selectively highly reflect light in a band centered about at a first preferred wavelength and to significantly reduce the reflection of light at a band centered about a second wavelength.

An EUV light source collector comprising:

• a plasma ignition point;
• a collecting mirror having a focus at the plasma ignition point and comprising a normal angle of incidence multi-layer reflecting surface;
• a focusing spectral filter comprising a plurality of nested grazing angle of incidence shells comprising reflective surfaces comprising multi-layer grazing angle of incidence reflective surfaces.

An EUV light source collector comprising:

• a plasma ignition point:
• an elliptical collector mirror having a first focus at the plasma ignition point and a second focus at an intermediate focus of the EUV light source;
• a debris shield intermediate the plasma ignition point and the elliptical collector mirror comprising a plurality of radially extending channels extending from the first focus and in symmetry about an axis of rotation passing through the first focus and aligned to the longitudinal axis of the elliptical collector mirror.

A method of reclaiming EUV light source collectors comprising a reflective surface that has become contaminated with debris comprising:

• opto-chemically cleaning the collector reflective surfaces in a cleaning chamber containing a carbon oxidizer containing gas and under irradiation from an ultraviolet light source.

A method of continuous removal of debris from a collector reflecting surface in an EUV light source for removal of plasma produced residue debris on the reflecting surface, wherein the reflecting surface comprises a first material and the residue debris comprises a second material and compounds of the second material comprising the steps of:

• heating the reflecting surface to effectively remove residue debris comprising the second material deposited on the reflecting surface;
• and,
• sputtering the compounds of the second material deposited on the reflecting surface using ions of the second material produced in the plasma.