Method and device for irradiating spots on a layer

A method of irradiating a layer including:

• directing and focusing a radiation beam to spot on said layer by means of at least one optical element;
• causing relative movement of the layer relative to said at least one optical element so that, successively, different portions of the layer are irradiated and an interspace between a surface of said at least one optical element nearest to said layer is maintained;
• and
• maintaining at least a portion of said interspace through which said radiation irradiates said spot on said layer filled with a liquid, the liquid being supplied via a supply conduit;
• characterized in that at least a portion of said liquid fills up a recess through which said radiation irradiates said spot,
• wherein said interspace between said layer and said surface of said at least one optical element nearest to said layer has a thickness H, the layer and the at least one optical element are moved relative to each other at a velocity V, the liquid is supplied via an outflow opening having a width W measured in a plane parallel to said layer and at a flow rate equal to 0.5*⋅*H*(W+⋅*H)*V, where ⋅ is a constant between 1 and 10 and ⋅ is a constant between 1 and 3.

A device for directing radiation to a layer including:

• at least one optical element for focussing radiation originating from said radiation source to a spot on said layer;
• a displacement structure for causing relative movement of the layer relative to said at least one optical element so that, successively, different portions of the layer are irradiated and an interspace between said layer and a surface of said at least one optical element nearest to said spot is maintained;
• and
• an outflow opening for supplying liquid to fill said interspace, in operation, said radiation irradiates said spot on said layer through said liquid,
• characterized in that said device further comprises a recess having an internal surface bounding at least said portion of said interspace through which said radiation irradiates said spot, said outflow opening being formed in said recess, wherein said recess is bounded by a passage in a wall between said spot and a surface of said at least one optical element nearest to said spot and by said surface of said at least one optical element nearest to said spot, said passage forming said outflow opening.

A structure for a lithography apparatus comprising a movable wafer support table configured to support a wafer, and an optical element, nearest to the wafer support table, configured to pass a radiation beam from a reticle or mask to the wafer, the structure configured for being located adjacent the optical element, configured to receive a liquid and configured to maintain an interspace between a bottom surface of the optical element and the wafer support table and through which the radiation beam irradiates the wafer, filled with the liquid, the structure comprising:

• an internal surface to bound at least a portion of the interspace between the bottom surface of the optical element and the wafer support table,
• a wall configured to be between the wafer and the surface of the optical element, wherein the interspace is bounded at least in part by the wall and by the surface of the optical element, wherein the wall is arranged to extend essentially perpendicularly to an optical axis, through the interspace, of the radiation beam and has its width in a horizontal direction larger than its height in a vertical direction,
• a passage formed in the wall, the passage arranged to allow the radiation beam and liquid to pass therethrough out onto the wafer, and
• a port configured to fill the interspace with the liquid, wherein the port is located inside the structure.

A structure for a lithography apparatus comprising a movable wafer support table configured to support a wafer, and an optical element, nearest to the wafer support table, configured to pass a radiation beam from a reticle or mask to the wafer, the structure configured for being located adjacent the optical element, configured to receive a liquid and configured to maintain an interspace between a bottom surface of the optical element and the wafer support table and through which the radiation beam irradiates the wafer, filled with the liquid, the structure comprising:

• an internal surface bounding at least a portion of the interspace between the bottom surface of the optical element and the wafer support table,
• a wall between the wafer and the surface of the optical element, wherein the interspace is bounded at least in part by the wall and by the surface of the optical element, wherein the wall comprises an essentially plane parallel plate arranged to extend essentially perpendicularly to an optical axis, through the interspace, of the radiation beam,
• a passage formed in the wall, the passage arranged to allow the radiation beam and liquid to pass therethrough out onto the wafer, and
• a port configured to fill the interspace with the liquid, wherein the port is located inside the structure.

A structure for a lithography apparatus comprising a movable wafer support table configured to support a wafer, and an optical element, nearest to the wafer support table, configured to pass a radiation beam from a reticle or mask to the wafer, the structure configured for being located adjacent the optical element, configured to receive a liquid and configured to maintain an interspace between a surface of the optical element and the wafer support table and through which the radiation beam irradiates the wafer, filled with the liquid, the structure comprising:

• an internal surface to bound at least a portion of the interspace between the surface of the optical element and the wafer support table,
• a wall configured to be between the wafer and the surface of the optical element, wherein the interspace is bounded at least in part by the wall and by the surface of the optical element, wherein the wall is arranged to have a surface nearest the wafer when supported by the wafer support table that is essentially perpendicular to an optical axis, through the interspace, of the radiation beam,
• a passage formed in the wall, the passage arranged to allow the radiation beam and liquid to pass therethrough out onto the wafer, and
• a port configured to fill the interspace with the liquid, wherein the port is located inside the structure.