Abstract: In an off-axis levelling procedure a height map of the substrate is generated at a measurement station. The height map is referenced to a physical reference surface of the substrate table. The physical reference surface may be a surface in which is inset a transmission image sensor. At the exposure station the height of the physical reference surface is measured and related to the focal plane of the projection lens. The height map can then be used to determine the optimum height and/or tilt of substrate table to position the exposure area on the substrate in best focus during exposure. The same principles can be applied to (reflective) masks.

Abstract: A system and method are used to protect a mask from being contaminated by airborne particles. They include providing a reticle secured in a two-part cover. The two part cover includes a removable protection device used to protect the reticle from contaminants. The cover can be held inside a pod or box that can be used to transport the cover through a lithography system from an atmospheric section to a vacuum section. While in the vacuum section, the removable cover can be moved during an exposure process during which a pattern on the reticle can be formed on a wafer.

Abstract: A system and method are used to protect a mask from being contaminated by airborne particles. They include coupling a reticle and a cover to protect the reticle. The cover includes a frame and a movable panel that moves to allow direct access of light to the reticle during an exposure process. The reticle and cover are moved to a stage using a robot gripper. The reticle and cover may be coupled to a baseplate before being moved. Corresponding alignment devices are coupled to the frame and the panel, the gripper and the panel, and the baseplate and the panel. The stage and the frame can have corresponding attachment devices. A pre-alignment device can be used to align the reticle before transporting it to a stage. The pre-alignment device and the frame can have corresponding alignment devices that can be used to perform the pre-alignment. Predetermined areas of the reticle can be hardened or shaped, such that less particles are produced during contact with the reticle.

Abstract: In a lithographic projection apparatus the positions and/or orientations of reflective optical elements is dynamically controlled. The position of a reflective optical element such as a mirror in an illumination or projection system is first measured using an absolute position sensor mounted on a reference frame and thereafter measured by a relative position sensor also mounted on said reference frame. The position of the element is controlled in accordance with the measured position, e.g. to maintain it stationary in spite of vibrations that might otherwise disturb it. The absolute sensor may be a capacitive or inductive sensor and the relative sensor may be an interferometer.

Abstract: A positioning device comprising a first part (1) which is movable relatively to a second part (2) in an X-direction and a Y-direction, said first part (1) comprising a carrier (5) on which a system of magnets (3) is arranged according to a pattern of rows (7) and columns (8) extending parallel to the X-direction and the Y-direction, respectively. The magnets in each row and column are arranged according to a Halbach array, i.e. the magnetic orientation of successive magnets in each row (7) and each column (8) rotates 90° counterclockwise. The second part (2) comprises an electric coil system (4) with two types of electric coils (C1, C2), one type having an angular offset of +45°, and the other type having an offset of −45° with respect to the X-direction. The magnet configuration causes a very strong magnetic field.

Abstract: In a lithographic apparatus using exposure radiation of a relatively short wavelength, e.g. 157 or 126 nm, a laminar flow of N2 is provided across parts of the beam path in or adjacent to moving components of the apparatus. The laminar flow is faster than the maximum speed of the moving components and the diffusion rate of air thereby minimizing the contamination of the N2 by mixing with air. Laminar flow may be ensured by providing partitions to divide the beam path into separate spaces, by covering rough or non-planar surfaces in components on or adjacent to the laminar flow and by providing aerodynamic members.

Abstract: In a lithographic projection apparatus the positions and/or orientations of reflective optical elements is dynamically controlled. The position of a reflective optical element such as a mirror in an illumination or projection system is first measured using an absolute position sensor mounted on a reference frame and thereafter measured by a relative position sensor also mounted on said reference frame. The position of the element is controlled in accordance with the measured position, e.g. to maintain it stationary in spite of vibrations that might otherwise disturb it. The absolute sensor may be a capacitive or inductive sensor and the relative sensor may be an interferometer.

Abstract: In a lithographic apparatus using exposure radiation of a relatively short wavelength, e.g. 157 or 126 nm, a laminar flow of N2 is provided across parts of the beam path in or adjacent to moving components of the apparatus. The laminar flow is faster than the maximum speed of the moving components and the diffusion rate of air thereby minimizing the contamination of the N2 by mixing with air. Laminar flow may be ensured by providing partitions to divide the beam path into separate spaces, by covering rough or non-planar surfaces in components on or adjacent to the laminar flow and by providing aerodynamic members.

Abstract: A lithographic apparatus has at least one compartment closely surrounding at least one of the mask and substrate holders but not either of the illumination or projection systems so as to reduce the volume that must be purged with gas transparent to the projection radiation. In a scanner, the compartment surrounding the mask holder preferably moves with the mask table and may be formed by a combination of a frame-shaped mask table driven in the scanning operation and stationary plates fixed relative to the projection and illumination systems.

Abstract: A positioning device comprising a first part (1) which is movable relatively to a second part (2) in an X-direction and a Y-direction, said first part (1) comprising a carrier (5) on which a system of magnets (3) is arranged according to a pattern of rows (7) and columns (8) extending parallel to the X-direction and the Y-direction, respectively. The magnets in each row and column are arranged according to a Halbach array, i.e. the magnetic orientation of successive magnets in each row (7) and each column (8) rotates 90° counter-clockwise. The second part (2) comprises an electric coil system (4) with two types of electric coils (C1, C2), one type having an angular offset of +45°, and the other type having an offset of −45° with respect to the X-direction. The magnet configuration causes a very strong magnetic field.

Abstract: In a lithographic projection apparatus a first part is shielded from a second part by a heat shield. The first part is required to have a temperature of a predetermined value and the second part has a characteristic that may influence the temperature of the first part. The characteristic may be a temperature deviating from the predetermined value, or a supply of radiation that may deviate the temperature of the first part from the predetermined value when incident on the first part. Heat shield temperature controlling means are provided to control a temperature of the heat shield to the predetermined value.

Abstract: A lithographic projection apparatus includes a radiation system for providing a projection beam of radiation having a wavelength &lgr;1 smaller than 50 nm; a support structure for supporting patterning structure, the patterning structure serving to pattern the projection beam according to a desired pattern; a substrate table for holding a substrate; and a projection system for projecting the patterned beam onto a target portion of the substrate. The apparatus further includes a radiation sensor which is located so as to be able to receive radiation out of the projection beam, said sensor comprising a radiation-sensitive material which converts incident radiation of wavelength &lgr;1 into secondary radiation; and sensing means capable of detecting said secondary radiation emerging from said layer.

Abstract: In a lithographic projection apparatus a first part is shielded from a second part by a heat shield. The first part is required to have a temperature of a predetermined value and the second part has a characteristic that may influence the temperature of the first part. The characteristic may be a temperature deviating from the predetermined value, or a supply of radiation that may deviate the temperature of the first part from the predetermined value when incident on the first part. Heat shield temperature controlling means are provided to control a temperature of the heat shield to the predetermined value.

Abstract: A position detection apparatus comprises a radiation source mounted on an isolated reference frame and a two-dimensional detector mounted adjacent said radiation source. The object whose position is to be detected has a retro-reflector mounted on it so as to reflect light emitted from the radiation source along a return path that is parallel to but displaced from the incident light path. The amount of displacement is dependent on the position of the object and is measured by the two-dimensional detector. Three such apparatus can be combined in a system to measure the position of the object in all six degrees of freedom.

Abstract: In a lithographic apparatus, a reference grating 11 mounted on the wafer table WT is illuminated with a measurement beam 20 incident in a direction independent of wafer table tilt. The diffraction orders are detected by detector 30 and used to determine the lateral shift in the wafer table resulting from a non-zero Abbe arm, and hence the Abbe arm, for calibration purposes. The detector 30 may be a detector also used for off-axis alignment of the wafer and wafer table.

Abstract: A positioning device has first and second object holders that are guided over a guiding surface extending parallel to an X-direction and parallel to a Y-direction perpendicular to the X-direction and which are displaceable over the guiding surface from a first position into a second position by means of a displacement system. The displacement system includes a first displacement unit and a second displacement unit to which the object holders can be alternately coupled. The first displacement unit is suitable for carrying out a first series of positioning steps of the first object holder in the first position and for displacing the first object holder from the first position into an intermediate position between the first and second positions.

Abstract: A supporting device (53) provided with a first part (69), a second part (71), and a gas spring (73) for supporting the second part relative to the first part parallel to a support direction (Z). The gas spring (73) comprises a pressure chamber (75) which is provided in an intermediate part (79) and is bounded by a piston (81) which is displaceable in the intermediate part (79) parallel to the support direction and is supported perpendicularly to the support direction by means of a static gas bearing (85). A stiffness of the supporting device parallel to the support direction is thus substantially entirely determined by a stiffness of the gas spring, and a low stiffness can be achieved through a suitable design of the gas spring. A transmission of vibrations directed parallel to the support direction from the first part to the second part is prevented as much as possible thereby. The invention also relates to a lithography device having a plurality of such supporting devices.

Abstract: In a lithographic projection apparatus, a time-saving height measurement method is used. While in a projection station (105,108,111) the pattern of a mask (129) is projected on the fields of a first substrate (120), the height of the fields of a second substrate (121) is measured in a measuring station (133). In the measuring station, the height of the substrate fields and the height of the substrate holder (113) are measured by a first height sensor (150) and a second height sensor (160), respectively, and the value of the height of the substrate holder associated with the ideal height of the substrate field is determined for each substrate field. In the projection station, only the height of the substrate holder (111) is controlled by a third height sensor (180). The second and third height sensors are preferably part of a composite XY interferometer system extended with a Z measuring axis.

Abstract: A positioning device is disclosed. The positioning device has a first part and a second part, the second part further has an object table. The second part may be displaced relative to the first part parallel to the XY-plane and may be rotated about the Z-axis by means of three motors. The motors are Lorentz type motors having a permanent magnet system and an electrical coil system cooperating therewith. The electrical coil systems each have windings which are substantially directed parallel to a main axis of the electrical coil system and perpendicular to the Z-axis. According to the invention, the main axis of each of the three motors encloses an angle of substantially 120.degree. with the main axis of each of the two other motors.

Abstract: A composite interferometer system has a plurality of X and/or Y measuring axes which co-operate with an X and/or Y measuring mirror arranged on an object. The interferometer system also has at least one Z measuring axis, which extends partly in an XY plane and co-operates with Z measuring mirrors arranged on the object and Z reflectors. Thus, a larger number of more accurate and reliable measurements can be performed with the interferometer system.