Abstract: Cooling devices are disclosed for use with mirrors and other optical elements subject to heating during use, especially as used in lithographic exposure apparatus. The cooling devices pose minimal risk of damage caused by coolant leaks, provide simplified maintenance, and reduce vibrations while providing good cooling performance. An exemplary cooling device includes a cooling element (e.g., Peltier element) proximal to the optical element and a heat-conduction member mounted on the heat-dissipating side of the cooling element. The heat-conduction member extends, within the exposure apparatus, away from the optical element, and the extended portion of the heat-conduction member is cooled.

Abstract: Multilayer-film (MLF) reflective mirrors are disclosed that have a highly precise surface profile. An exemplary MLF reflective mirror includes multilayer film in which layers of molybdenum (Mo) and layers of silicon (Si) are periodically deposited in an alternating manner on the surface of a mirror substrate. One or more selected regions of the multilayer film have been “shaved” away layer-wise as required to impart an in-plane distribution of removed material sufficient to correct a wavefront error in light reflected from the mirror. After such “layer-machining,” a single-layer film of Si (or Si-containing material) is applied to fill in the machined areas and restore the original contour, as designed, for the surface of the multilayer film. I.e., the Si film has a thickness distribution corresponding to the depth profile of material removed from the multilayer film. A capping layer can be deposited uniformly on the surface of the single-layer film.

Abstract: The present invention makes it possible to obtain a multilayer film reflective mirror 61 comprising a first multilayer film 67 which is formed by alternately laminating Mo layers 671 and Si layers 673 on a substrate 63, and a second multilayer film 65 which is formed on top of the first multilayer film 67, and which is formed by alternately laminating Mo layers 651 and Si layers 653, wherein the thickness of the Mo layers in the first multilayer film is substantially equal to or smaller than the thickness of the Mo layers in the second multilayer film, and the ratio of the thickness of the Mo layers to the thickness of the Si layers in the first multilayer film is different from the ratio of these thicknesses in the second multilayer film. As a result, a multilayer film reflective mirror with a low internal stress in which a drop in the reflectivity is suppressed can be obtained.

Abstract: An exposure apparatus that exposes an object to be exposed with light from an EUV light source. The light has an exposure wavelength component and a non-exposure wavelength component. The exposure apparatus has a detector that independently detects the quantity of light of the exposure wavelength component and the quantity of light of the non-exposure wavelength component of the light. Therefore, for example, even if the quantity of light of the exposure wavelength component and the quantity of light of the non-exposure wavelength component individually fluctuate, it is possible to accurately ascertain fluctuations in the characteristics of the optical system resulting from irradiation heat. As a result, it is also possible to achieve a high performance mirror adjustment system.

Abstract: Devices are disclosed for generating X-rays, especially in a vacuum chamber from plasma formed by irradiating a target material with laser light, that provide convenient removal from the vacuum chamber of high-frequency-maintenance components without disturbing other components. In one configuration denoted a liquid-jet-type of X-ray generator, a nozzle (for spraying target material) and a mirror are situated in a vacuum chamber. The nozzle has a higher maintenance frequency than the mirror. A flange member is provided on an outer wall of the vacuum chamber to cover an opening in the wall. The nozzle is connected to a conduit having a base mounted to the flange member. The nozzle is removable for maintenance by detaching the flange member and withdrawing the nozzle through the opening. Thus, the highest-frequency-maintenance component, the nozzle, is removed without moving or removing any other component in the chamber, such as the mirror.

Abstract: A multilayer mirror aims to reduce incidence angle dependence of reflectivity. A substrate is made of low thermal polished expansion glass with 0.2 nm RMS or less roughness of the surface. On the surface thereof formed is a Ru/Si multilayer having a wide full-width half maximum of peak reflectivity, and on the Ru/Si multilayer formed is a Mo/Si multilayer having a high peak reflectivity value. This enables higher reflectivity than when Ru/Si alone provided and a reflectivity peak having a wider full-width half maximum than when the Mo/Si multilayer alone provided. Since Ru absorbs EUV ray more than Mo does, higher reflectivity is obtainable than that of a structure having the Ru/Si multilayer formed on the Mo/Si multilayer. The multilayer with a wide full-width half maximum has small incidence angle dependence of reflectivity in spectral reflectivity, thereby achieving high imaging performance in projection optical system.

Abstract: The present invention makes it possible to obtain a multilayer film reflective mirror 61 comprising a first multilayer film 67 which is formed by alternately laminating Mo layers 671 and Si layers 673 on a substrate 63, and a second multilayer film 65 which is formed on top of the first multilayer film 67, and which is formed by alternately laminating Mo layers 651 and Si layers 653, wherein the thickness of the Mo layers in the first multilayer film is substantially equal to or smaller than the thickness of the Mo layers in the second multilayer film, and the ratio of the thickness of the Mo layers to the thickness of the Si layers in the first multilayer film is different from the ratio of these thicknesses in the second multilayer film. As a result, a multilayer film reflective mirror with a low internal stress in which a drop in the reflectivity is suppressed can be obtained.

Abstract: Devices are disclosed for generating X-rays, especially in a vacuum chamber from plasma formed by irradiating a target material with laser light, that provide convenient removal from the vacuum chamber of high-frequency-maintenance components without disturbing other components. In one configuration denoted a liquid-jet-type of X-ray generator, a nozzle (for spraying target material) and a mirror are situated in a vacuum chamber. The nozzle has a higher maintenance frequency than the mirror. A flange member is provided on an outer wall of the vacuum chamber to cover an opening in the wall. The nozzle is connected to a conduit having a base mounted to the flange member. The nozzle is removable for maintenance by detaching the flange member and withdrawing the nozzle through the opening. Thus, the highest-frequency-maintenance component, the nozzle, is removed without moving or removing any other component in the chamber, such as the mirror.

Abstract: Multilayer mirrors are disclosed for use especially in “Extreme Ultraviolet” (“soft X-ray,” or “EUV”) optical systems. Each multilayer mirror includes a stack of alternating layers of a first material and a second material, respectively, to form an EUV-reflective surface. The first material has a refractive index substantially the same as a vacuum, and the second material has a refractive index that differs sufficiently from the refractive index of the first material to render the mirror reflective to EUV radiation. The wavefront profile of EUV light reflected from the surface is corrected by removing (“machining” away) at least one surficial layer of the stack in selected region(s) of the surface of the stack. Machining can be performed such that machined regions have smooth tapered edges rather than abrupt edges. The stack can include first and second layer groups that allow the unit of machining to be very small, thereby improving the accuracy with which wavefront-aberration correction can be conducted.

Abstract: Methods and apparatus are disclosed for peripherally supporting X-ray-reflective mirrors such as used in X-ray microlithography systems and other X-ray optical systems. The methods provide effective physical support while reducing certain deformations in the reflective surface of the mirror. An embodiment of the method or mirror-support apparatus utilizes multiple “pushing” and “pushing” devices that apply a compressive stress and tensile stress, respectively, to respective locations on the peripheral-side surface of the mirror. One or more pushing devices and one or more pulling devices can be used as required. For example, at time of mirror fabrication, respective pushing devices can be placed adjacent concave-deviation regions and respective pulling devices can be placed adjacent convex-deviation regions on the reflective surface of the mirror.

Abstract: Multilayer-film mirrors are disclosed that exhibit high reflectivity to incident X-radiation independently of the angle of incidence and without significantly compromising optical performance. Also disclosed are X-ray optical systems and microlithography apparatus comprising such mirrors. In an embodiment a multilayer-film mirror is formed by alternately laminating Mo layers (a material in which the difference between its refractive index in the weak X-ray band and its refractive index in a vacuum is great) and Si layers (a material in which said difference is small) on a substrate. The ratio (&Ggr;) of the thickness of the Mo layer to the total of the thickness of the Mo layer and the thickness of the Si layer has a distribution based on the distribution of angles of incidence of X-radiation on the mirror surface.

Abstract: Multilayer-film mirrors are disclosed that include multiple units of Mo and Si layers formed on the surface of a mirror substrate and that exhibit reduced internal stress and hence improved imaging properties. Hence, the mirrors are especially suitable for use in X-ray optical systems such as used in X-ray lithography systems. In an exemplary mirror, a molybdenum oxide layer is formed on at least one Mo layer at the interface surface between the Mo layer and an adjacent Si layer. The molybdenum oxide layer is formed by irradiation with oxygen ions, or by forming at least a portion of the Mo layer in an atmosphere including oxygen.

Abstract: Multilayer-film mirrors are disclosed that exhibit high reflectivity to incident X-radiation independently of the angle of incidence and without significantly compromising optical performance. Also disclosed are X-ray optical systems and microlithography apparatus comprising such mirrors. In an embodiment a multilayer-film mirror is formed by alternately laminating Mo layers (a material in which the difference between its refractive index in the weak X-ray band and its refractive index in a vacuum is great) and Si layers (a material in which said difference is small) on a substrate. The ratio (&Ggr;) of the thickness of the Mo layer to the total of the thickness of the Mo layer and the thickness of the Si layer has a distribution based on the distribution of angles of incidence of X-radiation on the mirror surface.

Abstract: Methods and apparatus are disclosed for peripherally supporting X-ray-reflective mirrors such as used in X-ray microlithography systems and other X-ray optical systems. The methods provide effective physical support while reducing certain deformations in the reflective surface of the mirror. An embodiment of the method or mirror-support apparatus utilizes multiple “pushing” and “pushing” devices that apply a compressive stress and tensile stress, respectively, to respective locations on the peripheral-side surface of the mirror. One or more pushing devices and one or more pulling devices can be used as required. For example, at time of mirror fabrication, respective pushing devices can be placed adjacent concave-deviation regions and respective pulling devices can be placed adjacent convex-deviation regions on the reflective surface of the mirror.

Abstract: Methods are disclosed for correcting the wave aberrations of light reflected from multilayer-film mirrors as used in, e.g., optical systems as used for EUV lithography (EUVL) apparatus. Wave aberrations are corrected by addition and/or removal of one or more layers (typically layer-sets) to and from, respectively, the surface of the multilayer film of the mirror. In certain embodiments, layer-removal is monitored in situ by any of several techniques. In other embodiments, mirror substrates are processed to a prescribed shape precision and surface roughness, followed by formation of the multilayer film and assembly of the mirrors into the intended optical assembly. The wave aberration is measured at operating wavelength. If the measured wave aberration is not within specifications, then the mirrors are corrected individually by selective removal and/or addition of layer-set(s). The corrected mirrors are reassembled and re-tested as an optical assembly. This cycle is repeated as required.

Abstract: Multilayer-film mirrors are disclosed that include multiple units of Mo and Si layers formed on the surface of a mirror substrate and that exhibit reduced internal stress and hence improved imaging properties. Hence, the mirrors are especially suitable for use in X-ray optical systems such as used in X-ray lithography systems. In an exemplary mirror, a molybdenum oxide layer is formed on at least one Mo layer at the interface surface between the Mo layer and an adjacent Si layer. The molybdenum oxide layer is formed by irradiation with oxygen ions, or by forming at least a portion of the Mo layer in an atmosphere including oxygen.

Abstract: X-ray-generation devices are disclosed that generate X-rays in a stable manner over extended periods of time. An exemplary device includes an anode electrode and a cathode electrode coaxially arranged, and an insulating member. A nozzle connected to a reservoir of fluid target material directs a flow of fluid target material to the anode electrode. Meanwhile, a pulsed high voltage is applied between the anode electrode and cathode electrode in coordination with the supply of target material. The pulses are timed such that, whenever a unit of target material reaches a tip of the anode electrode, a plasma sheath generated at the surface of the insulating member also reaches the tip of the anode electrode. Hence, the target material is supplied automatically as required to produce X-rays continuously over an extended time period. Intense X-ray fluxes can be produced in a stable manner by monitoring the rate at which target material is supplied to the plasma, relative to the timing of discharge pulses.

Abstract: An optical sample X-ray testing apparatus including an X-ray source which is configured to radiate X-rays including a group of line spectra. At least one line spectrum selecting device is provided between the X-ray source and an optical sample and configured to direct substantially one line spectrum among the group of line spectra from the X-ray source toward the optical sample. An optical characteristics finding device is configured to find optical characteristics of the optical sample based on radiation of the substantially one line spectrum through the line spectrum selecting device onto the optical sample.

Abstract: Multilayer mirrors are disclosed for use especially in “Extreme Ultraviolet” (“soft X-ray,” or “EUV”) optical systems. Each multilayer mirror includes a stack of alternating layers of a first material and a second material, respectively, to form an EUV-reflective surface. The first material has a refractive index substantially the same as a vacuum, and the second material has a refractive index that differs sufficiently from the refractive index of the first material to render the mirror reflective to EUV radiation. The wavefront profile of EUV light reflected from the surface is corrected by removing (“machining” away) at least one surficial layer of the stack in selected region(s) of the surface of the stack. Machining can be performed such that machined regions have smooth tapered edges rather than abrupt edges.

Abstract: Methods and devices are disclose for use in holding mirrors as used in any of various X-ray optical systems. In this context, “X-ray” encompasses the so-called “soft X-ray” or “EUV” wavelengths. The X-ray optical systems can be used, for example, in EUV microlithography systems. A fluid cavity (e.g., an elastic toroidal ring) extends around the circumference of an X-ray mirror. The cavity defines a lumen that is filled with a fluid. The fluid can be static or flowing, and can be a gas or liquid. Holding members are disposed evenly spaced around the circumference of the cavity. Thus, any stress imparted to the mirror by holding is distributed evenly around the circumference of the mirror.