Cleaning device, a lithographic apparatus and a lithographic apparatus cleaning method

An immersion lithographic projection apparatus, comprising:

• a substrate table constructed and arranged to hold a substrate;
• a projection system configured to project a patterned beam of radiation onto the substrate;
• a sonic transducer having a sonic wave emitting surface facing upward and non-perpendicular to, in use, a surface of the immersion lithographic apparatus to be cleaned other than a surface of the transducer and configured to clean the surface, wherein, in use, a perpendicular of the sonic wave emitting surface intersects the surface;
• a liquid supply system constructed and arranged to supply liquid between the sonic transducer and the surface to be cleaned;
• and
• a cleaning liquid outlet configured to allow an outflow of cleaning fluid during application of sonic waves to the surface to be cleaned, the cleaning liquid outlet positioned substantially in the center of an area to which the liquid is provided and arranged such that the sonic wave emitting surface extends around or on at least two opposite sides of the outlet and extends substantially perpendicularly to the direction of the cleaning fluid outflow.

A method of cleaning a surface of an immersion lithographic projection apparatus using sonic waves emanating from a sonic transducer, comprising:

• covering the surface to be cleaned and a surface of the sonic transducer in liquid;
• introducing sonic waves into the liquid using a sonic wave emitting surface of the transducer facing upward, and non-perpendicular to, the surface to be cleaned, the surface to be cleaned being other than a surface of the transducer, wherein a perpendicular of the sonic wave emitting surface intersects the surface to be cleaned;
• and
• extracting liquid through a liquid outlet that adjoins the surface to be cleaned during application of sonic waves to the surface to be cleaned, the cleaning liquid outlet positioned substantially in the center of an area to which the liquid is provided and arranged such that the sonic wave emitting surface extends around or on at least two opposite sides of the outlet and extends substantially perpendicularly to the direction of flow of liquid through the outlet.

A lithographic projection apparatus, comprising:

• a substrate table constructed and arranged to hold a substrate;
• a projection system configured to project a patterned beam of radiation onto the substrate;
• a liquid confinement structure configured to confine liquid between the projection system and the substrate table during projection of the patterned beam onto the substrate;
• and
• a cleaning device to clean a surface of a component of the lithographic projection apparatus, the cleaning device comprising a sonic transducer having a sonic wave emitting surface, the cleaning device being removably attachable or sealable to the liquid confinement structure, the cleaning device further comprising a liquid inlet to supply liquid to a reservoir between the surface and the sonic transducer, and positioned substantially in the center of an area to which the liquid is provided to the reservoir to encourage a radial flow of liquid past the surface, wherein the sonic transducer is configured to emit sonic waves through the liquid from the inlet onto the surface,
• wherein, when the cleaning device is attached or sealed to the liquid confinement structure, a perpendicular of the sonic wave emitting surface intersects the liquid confinement structure.

A method of cleaning a surface of a component of a lithographic projection apparatus, the method comprising:

• removably attaching or sealing to a liquid confinement structure of the lithographic projection apparatus a cleaning device to clean the surface, the cleaning device comprising a sonic transducer having a sonic wave emitting surface and a liquid inlet to supply liquid to a reservoir between the surface and the sonic transducer, the inlet positioned substantially in the center of an area to which the liquid is provided to the reservoir;
• providing a liquid on the surface using the inlet;
• inducing a radial flow in the liquid past the surface using the inlet;
• and
• providing sonic waves through the liquid supplied by the inlet onto the surface,
• wherein, when the cleaning device is attached or sealed to the liquid confinement structure, a perpendicular of the sonic wave emitting surface intersects the liquid confinement structure.

A lithographic projection apparatus comprising:

• a sonic transducer with a face facing and non-perpendicular to, in use, a surface to be cleaned;
• a liquid inlet configured to supply liquid to a reservoir between the sonic transducer and the surface, and positioned substantially in the center of an area to which the liquid is provided to the reservoir to encourage a radial flow of liquid past the surface,
• wherein the sonic transducer is configured to emit sonic waves from the face through the liquid onto the surface to clean the surface, wherein, in use, a perpendicular of the sonic wave emitting surface intersects the surface;
• and
• an extractor configured to remove liquid from between the sonic transducer and the surface.

A lithographic projection apparatus, comprising:

• a substrate table constructed and arranged to hold a substrate;
• a projection system configured to project a patterned beam of radiation onto the substrate;
• a liquid confinement structure configured to confine liquid between the projection system and the substrate table during projection of the patterned beam onto the substrate;
• and
• a cleaning device to clean a surface of a component of the lithographic projection apparatus, the cleaning device comprising a sonic transducer having a sonic wave emitting surface, the cleaning device being movable to adjacent a bottom surface of the liquid confinement structure and the cleaning device further comprising a liquid inlet to supply liquid to a reservoir between the surface and the sonic transducer, the liquid inlet positioned substantially in the center of an area to which the liquid is provided to the reservoir to encourage a radial flow of liquid past the surface, wherein the sonic transducer is configured to emit sonic waves through the liquid from the inlet onto the surface,
• wherein, when the cleaning device is adjacent the liquid confinement structure, a perpendicular of the sonic wave emitting surface intersects the liquid confinement structure.