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Gaurav Keswani, Fremont US

Gaurav Keswani, Fremont, CA US

Patent application numberDescriptionPublished
20080198348Apparatus and methods for minimizing force variation from immersion liquid in lithography systems - A lithographic projection apparatus includes an optical assembly that projects an image onto a workpiece, and a containment member disposed adjacent to a lower end of the optical assembly. The containment member has an aperture through which an exposure beam passes from the optical assembly to the workpiece. The lithographic projection apparatus also includes a stage assembly including a workpiece table that supports the workpiece adjacent to the containment member. A space between the containment member and the workpiece is filled with an immersion liquid. The lithographic projection apparatus further includes a liquid collection system that has a recess in the workpiece table that receives immersion liquid that overflows the space between the containment member and the workpiece. At least part of the recess is disposed radially outward of the workpiece. The recess is partially filled with a porous material.08-21-2008
20080212050Apparatus and methods for removing immersion liquid from substrates using temperature gradient - Apparatus and methods assist in the removal of immersion liquid from a surface of a substrate. In particular, the apparatus/method removes immersion liquid from a surface of a substrate that has been subjected to immersion lithographic exposure. A temperature control unit controls a temperature of the substrate to create a temperature gradient across at least a portion of the surface of the substrate such that a first portion of the surface of the substrate has a first temperature that is higher than a second temperature of a second portion of the surface of the substrate. The temperature gradient induces the immersion liquid remaining on the substrate to move from the higher temperature portion(s) toward the lower temperature portion(s).09-04-2008
20080225246Apparatus and methods for keeping immersion fluid adjacent to an optical assembly during wafer exchange in an immersion lithography machine - Apparatus and methods keep immersion liquid in a space adjacent to an optical assembly. An optical assembly projects an image onto a substrate supported adjacent to the optical assembly by a substrate table. An insertion member insertable into the space between the optical assembly and the substrate, the substrate table, or both, divides the immersion liquid into a first portion and a second portion, the first portion disposed between the optical assembly and the insertion member, and the second portion disposed between the insertion member and the substrate, the substrate table, or both. The insertion member keeps the optical assembly in contact with the first portion when the substrate is moved away from being disposed adjacent to the optical assembly.09-18-2008
20080225248Apparatus, systems and methods for removing liquid from workpiece during workpiece processing - Apparatus, systems and methods remove liquid from a workpiece. A first station subjects a workpiece to processing that leaves a liquid on a surface of the workpiece. A second station is disposed at a location spaced apart from the first station. A porous member is disposed between the first and second stations. The porous member has a liquid-phyllic surface that faces the workpiece and is spaced from a surface of the workpiece by a gap. The porous member has a length in a direction perpendicular to a movement direction in which the workpiece moves from the first station to the second station, the length being at least as large as a dimension of the workpiece in the direction perpendicular to the movement direction.09-18-2008
20080231822Nozzle to help reduce the escape of immersion liquid from an immersion lithography tool - An immersion lithography tool with a diverter element, positioned between the immersion element and the substrate, for altering the “footprint” or shape of the meniscus of the body of immersion liquid between the last optical element and an immersion element on one side, and the substrate on the other side when the substrate is moved. The apparatus includes a substrate holder to hold the substrate having an imaging surface and a projection optical system having a last optical element. The projection optical system projects an image onto a target imaging area on the substrate through the immersion liquid filled in a gap between the imaging surface of the substrate and the last optical element. An immersion element maintains the immersion fluid in the gap. The diverter element is positioned between the immersion element and the substrate. The diverter element alters the footprint shape of the meniscus of the body of immersion liquid, thereby preventing or reducing the amount of leakage from a space between the substrate and the immersion element.09-25-2008
20080231823Apparatus and methods for reducing the escape of immersion liquid from immersion lithography apparatus - A stage assembly includes a workpiece table that supports the workpiece adjacent to an optical assembly. An environmental system supplies and removes immersion liquid to and from a space between the workpiece and the optical assembly to form an immersion area. The environmental system has a lower surface disposed opposite from an upper surface of the workpiece and/or the workpiece table. The lower surface is spaced a first distance from the workpiece and/or the workpiece table to form a meniscus at a periphery of the immersion area. An edge member is provided on the environmental system and extends past the lower surface of the environmental system so that a lower portion of the edge member is spaced a second distance, smaller than the first distance, from the upper surface of the workpiece and/or the workpiece table at a position beyond the periphery of the immersion area.09-25-2008
20090002648Gas curtain type immersion lithography tool using porous material for fluid removal - A gas curtain type immersion lithography apparatus has a fluid removing porous region adjacent the gas inlet to prevent evaporative cooling. The apparatus includes a substrate holder which holds a substrate having an imaging surface and a projection optical system having a last optical element. The projection optical system projects an image onto a target imaging area on the substrate through an immersion fluid filled in a gap between the imaging surface of the substrate and the last optical element. An immersion element maintains the immersion fluid in the gap. Gas is provided through an inlet into the gap. A porous region is provided adjacent the gas inlet. Immersion fluid that collects near the gas inlet is removed by the porous region.01-01-2009
20090231560Immersion lithography apparatus and method having movable liquid diverter between immersion liquid confinement member and substrate - An immersion lithography apparatus includes a projection system having a final optical element and a stage that is movable to a position below the projection system such that a gap exists between the final optical element and a surface of the stage. An immersion liquid fills the gap between the surface and the final optical element. A liquid confinement member maintains the immersion liquid in the gap. The immersion liquid has a meniscus where the liquid contacts ambient gas, the meniscus defining a footprint of an immersion area. A movable liquid diverter is positioned between the liquid confinement member and the stage. The movable liquid diverter moves relative to the liquid confinement member in a direction parallel to the surface of the stage, and includes an opening that surrounds the immersion area, the opening contacting or being slightly spaced from the immersion area when the stage is stationary.09-17-2009
20090237631Apparatus and methods for recovering fluid in immersion lithography - An immersion lithography apparatus includes a projection system having a final optical element, a movable stage that is movable below the projection system such that a gap exists between the final optical element and a surface of the stage, an immersion liquid being filled in the gap, a liquid confinement member and a liquid diverter. The liquid confinement member maintains the immersion liquid in the gap, and includes a liquid recovery portion that faces the stage surface and recovers liquid from the gap. The liquid recovery portion includes a first porous portion through which a first suction force is applied and a second porous portion through which a second suction force less than the first suction force is applied, the second portion being located outward of the first portion. The liquid diverter is positioned between the stage and at least the first porous portion.09-24-2009
20100134773APPARATUS AND METHOD TO CONTROL VACUUM AT POROUS MATERIAL USING MULTIPLE POROUS MATERIALS - An immersion liquid confinement apparatus recovers an immersion liquid from an immersion area that includes a gap between a projection system and an object of exposure in an immersion lithography system. The apparatus includes a confinement member that includes an outlet and an aperture through which a patterned image is projected onto the object. A first liquid-permeable member covers the outlet and has a first surface that faces the object and a second surface opposite the first surface, the second surface contacting a first chamber. A second liquid-permeable member has first and second oppositely-facing surfaces, the first surface of the second liquid-permeable member contacts the first chamber, the second surface of the second liquid-permeable member contacts a second chamber that is different from the first chamber. A hydrophobic porous member is provided between the first chamber and a vacuum system that supplies a low pressure to the first chamber.06-03-2010
20100156198SHIELD LAYER PLUS REFRIGERATED BACKSIDE COOLING FOR PLANAR MOTORS - According to one aspect of the present invention, a motor arrangement includes at least one coil, a cover plate, and a shield layer. The at least one coil has a first side and a second side. The cover plate is positioned substantially over the first side of the at least one coil at a distance from the at least one coil. The shield layer is positioned between the first side of the at least one coil and the cover plate, and has a top surface. The top surface contacts the cover plate, and includes a liquid and a gas that form a mixture and cause the top surface to have a substantially constant temperature.06-24-2010
20100220301APPARATUS AND METHOD TO CONTROL LIQUID STAGNATION IN IMMERSION LIQUID RECOVERY - An immersion liquid confinement apparatus confines an immersion liquid in an immersion area that includes a gap between a projection system and an object of exposure in an immersion lithography system. The apparatus also recovers the immersion liquid from the immersion area. The apparatus includes a confinement member and a liquid-permeable member. The confinement member includes an outlet and an aperture through which a patterned image is projected onto the object. The liquid-permeable member covers the outlet and has a first surface that faces the object and a second surface opposite the first surface, the second surface contacting a chamber. The confinement member includes at least one liquid inlet within the chamber through which a liquid is introduced into the chamber to reduce liquid from becoming stagnated within the chamber.09-02-2010
20100271159Electromagnetic Coil Design for Improved Thermal Performance - Methods and apparatus for improving the thermal performance of electromagnetic coils are disclosed. According to one aspect of the present invention, an electromagnetic actuator includes a core and a coil. The coil is formed form a conductor wire that includes a plurality of windings. The windings are arranged around the core, and include at least a first set of windings and a second set of windings. The first set of windings has a different geometry from the second set of windings.10-28-2010
20110164239Apparatus and method for recovering liquid droplets in immersion lithography - Immersion fluid remaining on a portion of a substrate after that portion has passed an immersion nozzle is removed by moving the substrate relative to an immersion nozzle so that the portion of the substrate on which the immersion fluid remains is passed by the immersion nozzle again. A path is determined along which the substrate is to be moved to remove the remaining immersion fluid. The path can be determined based upon previous movements of the substrate, including factors such as the speed and/or length of the previous movements. Alternatively, portions of the substrate on which immersion fluid remains can be detected, and then the substrate can be moved so that the portion of the substrate on which the immersion fluid remains is passed by the immersion nozzle based on the results of the detection. Immersion fluid also can be removed from the stage surface located beyond the substrate.07-07-2011

Patent applications by Gaurav Keswani, Fremont, CA US