摘要:
Reticles and apparatus for performing charged-particle-beam microlithography, and associated methods, are disclosed, in which the pattern to be transferred to a sensitive substrate is divided according to any of various schemes serving to improve throughput and pattern-transfer accuracy. The methods and apparatus are especially useful whenever a divided stencil reticle is used that includes complementary pattern portions.
摘要:
Methods are disclosed for reducing effects of thermal expansion of a sensitive substrate arising during microlithographic exposure of the substrate using a charged particle beam. Thermal expansion ordinarily causes lateral shift of exposure position of dies (chips) on the substrate which tends to reduce the positional accuracy with which images of the dies are formed on the substrate. Generally, regions of the substrate where entire dies are formed are exposed first, followed by regions (especially peripheral regions) exposed with only portions of dies. In addition, the substrate can be mounted on a wafer chuck configured to circulate a heat-transfer gas in contact with the substrate to remove heat from the substrate. In addition, the wafer chuck can be maintained at a constant temperature by circulating a liquid coolant through a conduit in the body of the wafer chuck.
摘要:
Charged-particle-beam (CPB) apparatus and methods are disclosed that achieve efficient correction of imaging conditions such as shape-astigmatic aberrations, etc., caused by differences in the distribution of pattern elements within respective subfields of the reticle. Indices based on the pattern-element distributions within subfields are stored, together with corresponding optical-correction data for the subfields. As the subfields are exposed, respective data are recalled and the exposure is performed with optical corrections made according to the data. The indices are determined beforehand from pattern data at time of reticle manufacture. The tabulated data are rewritable with changes in apparatus parameters such as beam-current density and beam-divergence angle. Intermediate data can be determined by interpolation of tabulated data.
摘要:
Apparatus and methods are disclosed for performing highly precise mark detection by obtaining a large signal as a result of the efficient capture of secondary electrons (SEs) emitted from a surface of a specimen. A charged-particle beam is directed at a location (e.g., a mark) on the specimen (e.g., reticle or wafer). SEs emitted from the location are detected using one or more secondary-electron collectors or detectors. To guide the SEs toward the secondary-electron collectors or detectors, a magnetic flux is created that extends radially outward in the vicinity of the surface of the specimen. E.g., an objective lens is situated above the specimen adjacent the specimen surface, and an electromagnetic lens is placed below the specimen adjacent the lower surface of the specimen. The magnetic fields produced by these lenses can be mutually repulsive to form a resultant magnetic flux near the upper surface of the specimen that extends radially outward parallel with the upper surface of the specimen. Thus, electrons can escape only radially outward parallel to the sample surface to the secondary-electron collectors or detectors. The apparatus provides a stable charged-particle beam without charging because the SE collector or detector removes SEs from the vicinity of the optical axis.
摘要:
Fiducial mark bodies are provided for use in CPB microlithography apparatus and methods. Such bodies are especially useful for attachment to the wafer stage of such apparatus, for measuring a distance between a reference position of the CPB-optical system of the apparatus and a reference position of an optical-based alignment sensor of the apparatus. The mark bodies provide improved accuracy of these and other positional measurements. A typical mark body is made of a substrate plate (e.g., quartz or quartz-ceramic) having a low coefficient of thermal expansion. Mark elements are defined on the substrate plate by a layer of heavy metal (e.g. are Ta, W, or Pt). The mark body includes a surficial or interior layer of an electrically conductive light metal that prevents electrostatic charging of the mark body and can be connected to ground.
摘要:
Fiducial mark bodies are provided for use in CPB microlithography apparatus and methods. Such bodies are especially useful for attachment to the wafer stage of such apparatus, for measuring a distance between a reference position of the CPB-optical system of the apparatus and a reference position of an optical-based alignment sensor of the apparatus. The mark bodies provide improved accuracy of these and other positional measurements. A typical mark body is made of a substrate plate (e.g., quartz or quartz-ceramic) having a low coefficient of thermal expansion. Mark elements are defined on the substrate plate by a layer of heavy metal (e.g. are Ta, W, or Pt). The mark body includes a surficial or interior layer of an electrically conductive light metal that prevents electrostatic charging of the mark body and can be connected to ground.
摘要:
Exposure apparatus are disclosed that can control, to high precision, exposure doses on a photosensitive substrate of a mask pattern defined on a reflective mask as the pattern is being exposed on the substrate using a projection-optical system. An exemplary apparatus includes a first illumination sensor for detecting light that is incident on a reflective mask from an illumination system and a second illumination sensor for detecting light that has propagated from the illumination system to a reference reflective surface on the reflective mask, reflected from the reference reflective surface, and arrived at an image surface of the projection-optical system. Calibration of the first sensor is performed based on detection data obtained by the first sensor and detection data obtained by the second sensor. Exposure of the substrate is controlled based on the detection data obtained by the calibrated first sensor.
摘要:
Exposure apparatus are disclosed that can control, to high precision, exposure doses on a photosensitive substrate of a mask pattern defined on a reflective mask as the pattern is being exposed on the substrate using a projection-optical system. An exemplary apparatus includes a first illumination sensor for detecting light that is incident on a reflective mask from an illumination system and a second illumination sensor for detecting light that has propagated from the illumination system to a reference reflective surface on the reflective mask, reflected from the reference reflective surface, and arrived at an image surface of the projection-optical system. Calibration of the first sensor is performed based on detection data obtained by the first sensor and detection data obtained by the second sensor. Exposure of the substrate is controlled based on the detection data obtained by the calibrated first sensor.
摘要:
A substrate conveyor apparatus carries a substrate on which patterns are formed, carries the substrate in a state protected by a protective cover when the substrate is not used, and carries a cover protection means that covers the inner surface of the protective cover when the substrate is used. The substrate conveyor apparatus has a grounding means that grounds the substrate or the protective cover.
摘要:
With respect to a substrate conveyor apparatus that, being a substrate conveyor apparatus that carries substrates on which patterns are formed, carries the substrates in a state protected by a protective cover when the substrate is not used, a substrate conveyor apparatus having a cover protection means that conceals the inner surface of the protective cover when the substrate is used.