A glass including silica and titania is disclosed. An average hydroxyl concentration of a plurality segments of the glass is in a range from about 20 ppm to about 450 ppm, an average titania concentration of the plurality of segments is in a range from about 6 wt. % to about 12 wt. %, and each segment of the plurality of segments has a length of about 12.7 mm, a width of about 12.7 mm, and a height of about 7.62 mm. The hydroxyl concentration of each segment is measured using a Fourier transform infrared spectroscopy in transmission, the refractive index is measured using an optical interferometer with a 633 nm operating wavelength and a resolution of 270 microns270 microns pixel size, and the average titania concentration is determined based upon the measured refractive index.

An ElectroStatic Chuck (ESC) including a chucking surface having at least a portion covered with a coating of silicon oxide (SiO.sub.2), silicon nitride (Si.sub.3N.sub.4) or a combination of both. The coating can be applied in situ a processing chamber of a substrate processing tool and periodically removed and re-applied in situ to create fresh coating.

There is provided a substrate holding apparatus including a base provided with a gap and a reflection member disposed in the gap and configured to reflect light that has transmitted the substrate to the substrate side, and an exposure apparatus including the substrate holding apparatus.

An object table to support an object, the object table having a support body, an object holder to hold an object, an opening adjacent an edge of the object holder, and a channel in fluid communication with the opening via a passageway, wherein the channel is defined by a first material which is different to a second material defining the passageway.

A projection exposure apparatus for semiconductor lithography includes: a light source for generating optical used radiation by which structures arranged on a reticle can be imaged onto a wafer; a plurality of optical elements for guiding and manipulating the used radiation; and a plurality of position sensors for determining the position of at least some of the optical elements. At least some of the position sensors are arranged on a measurement structure that is at least partially decoupled mechanically and/or thermally from the further components of the projection exposure apparatus. The measurement structure has at least two mechanically decoupled substructures. The first substructure has a lower coefficient of thermal expansion than the second substructure. The second substructure has a greater stiffness than the first substructure.

In a lithographic projection apparatus, a liquid supply system maintains liquid in a space between a projection system of the lithographic projection apparatus and a substrate. A sensor positioned on a substrate table, which holds the substrate, is configured to be exposed to radiation when immersed in liquid (e.g., under the same conditions as the substrate will be exposed to radiation). By having a surface of an absorption element of the sensor, that is to be in contact with liquid, formed of no more than one metal type, long life of the sensor may be obtained.

An apparatus and method for cleaning a contaminated surface of a lithographic apparatus are provided. A liquid confinement structure comprises at least two openings used to supply and extract liquid to a gap below the structure. The direction of flow between the openings can be switched. Liquid may be supplied to the gap radially outward of an opening adapted for dual flow. Supply and extraction lines to respectively supply liquid to and extract liquid from the liquid confinement structure have an inner surface that is resistant to corrosion by an organic liquid. A corrosive cleaning fluid can be used to clean photo resist contamination.

A porous member is used in a liquid removal system of an immersion lithographic projection apparatus to smooth uneven flows. A pressure differential across the porous member may be maintained at below the bubble point of the porous member so that a single-phase liquid flow is obtained. Alternatively, the porous member may be used to reduce unevenness in a two-phase flow.

An ElectroStatic Chuck (ESC) including a chucking surface having at least a portion covered with a coating of silicon oxide (SiO.sub.2), silicon nitride (Si.sub.3N.sub.4) or a combination of both. The coating can be applied in situ a processing chamber of a substrate processing tool and periodically removed and re-applied in situ to create fresh coating.

A debris mitigation system for use in a radiation source. The debris mitigation system comprises a contamination trap. The contamination trap comprises a debris receiving surface arranged to receive liquid metal fuel debris emitted from a plasma formation region of the radiation source. The debris receiving surface is constructed from a material that reacts with the liquid metal fuel debris to form an intermetallic layer on the debris receiving surface.