Abstract: Charged-particle-beam pattern-transfer methods and apparatus are disclosed. Circuit patterns on a mask are divided into a plurality of fields, each field including respective connection ends. Fields that are to be adjacent as transferred to a substrate include a common portion of the circuit pattern in their respective connection ends. The common portions are projected onto the substrate to substantially overlap. The connection ends are illuminated by an image of a shaping aperture image that is illuminated with a charged-particle beam. The shaping-aperture image can be scanned across the fields so that wafer areas corresponding to the connection ends are exposed during exposure of the connecting adjacent fields and so that the dose received by the wafer is substantially uniform. The shaping-aperture image can be vibrated in a direction perpendicular to a scanning direction to illuminate connection ends. The vibration provides uniform dose on the wafer in areas corresponding to the connection ends.

Abstract: 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.

Abstract: Methods are disclosed for reducing distortions, differences in focal point-positions, and astigmatic blurring of a pattern defined on a reticle and projected onto a sensitive substrate using a charged particle beam. The methods reduce variations in the distribution of beam current as projected onto the substrate. To such end, a charged particle beam passing through pattern features as defined on the reticle is projected onto a region on the substrate. The reticle is provided with multiple “micro features” each having a size less than the resolution limit of the projection-optical system. The micro features can be provided on a portion of the reticle having a low feature density.

Abstract: An exposure method using a charged particle beam is used to improve the accuracy of stitching the patterns according to the divided pattern transfer. The exposure method according to the present invention comprises dividing the pattern into a plurality of subfields arranged in stripes; forming the subfields (41L) and (41R) laid around the boundary in the adjacent stripes (49L) and (49R), exposing the subfields (41L) and (41R) by half the exposure time amount, and overlapping the images of the patterns of the subfields (41L) and (41R) at substantially the same position on the wafer.

Abstract: Methods and apparatus are disclosed for reducing thermal deformation of “upstream” marks (as used for alignment and/or calibration) situated on a reticle or on a reticle plane (e.g., on the reticle stage), thereby facilitating more accurate transfer of the reticle pattern to a sensitized substrate (e.g., semiconductor wafer) using a charged particle beam (e.g., electron beam). The charged particle beam illuminates an upstream mark situated on the reticle or on a reticle plane and projects an image of the illuminated upstream mark onto a corresponding “downstream” mark situated on a substrate plane. A shield is situated upstream of the upstream mark and serves to block downstream passage of the charged particle beam except to illuminate the upstream mark or a portion of the upstream mark. The upstream mark can be situated on the reticle or on a mark member situated in the reticle plane.

Abstract: Methods are disclosed for transferring a pattern from a mask to a sensitive substrate. The mask is illuminated substantially orthogonally with a charged particle beam propagating along an optical axis. An image of the charged particle beam that has passed through the mask is projection-exposed onto the substrate. At multiple locations displaced from each other in the optical-axis direction, a size measurement is obtained on a transverse profile of the beam as incident on at least one of the mask and substrate. From the size measurements, a respective parallelism of the beam incident to the mask and/or substrate is determined. From these determinations, the parallelism of the beam relative to the mask and/or substrate is adjusted as required.

Abstract: Charged-particle-beam pattern-transfer methods and apparatus are disclosed. Circuit patterns on a mask are divided into a plurality of fields, each field including respective connection ends. Fields that are to be adjacent as transferred to a substrate include a common portion of the circuit pattern in their respective connection ends. The common portions are projected onto the substrate to substantially overlap. The connection ends are illuminated by an image of a shaping aperture image that is illuminated with a charged-particle beam. The shaping-aperture image can be scanned across the fields so that wafer areas corresponding to the connection ends are exposed during exposure of the connecting adjacent fields and so that the dose received by the wafer is substantially uniform. The shaping-aperture image can be vibrated in a direction perpendicular to a scanning direction to illuminate connection ends. The vibration provides uniform dose on the wafer in areas corresponding to the connection ends.

Abstract: Charged-particle-beam (CPB) methods and apparatus are disclosed that achieve efficient correction of imaging distortions or astigmatisms (e.g., shape astigmatism) arising from differences in feature distributions within individual exposure units of a divided reticle defining a pattern for use in divided-pattern projection-exposure CPB microlithography. Before exposure of the reticle, data concerning the feature distribution inside each exposure unit of the reticle are evaluated so as to produce a respective "index" datum for the exposure units. Corresponding to each datum is a profile of values of imaging parameters. These data are stored as a look-up table in a memory of a controller. The table is queried when an exposure unit of the reticle comes up for exposure. The index of the respective exposure unit provides a key to the respective values of the imaging parameters to be applied as the exposure unit is being exposed. As conditions dictate, the data in the table can be overridden.

Abstract: Methods are disclosed for improving the accuracy of pattern registration between various layers formed on a sensitive substrate by microlithography using a charged-particle beam, especially registration accuracy as affected by rotation of image portions relative to corresponding image portions in an earlier applied layer. Errors in rotational angle of a pattern transferred to the n.sup.th layer and the arrangement direction of the transferred pattern on the substrate are measured. During projection of the (n+m).sup.th (e.g., the (n+1).sup.th) layer, the rotational angle of images that have passed through the mask subfields is corrected according to the measured rotational angle. Also, the deflection direction of the images on the substrate that have passed through the mask subfields is corrected according to the measured arrangement direction. The transfer subfields in the (n+m).sup.th layer can be accurately stitched together and corresponding transferred pattern in the n.sup.th and (n+m).sup.

Abstract: Charged-particle-beam (CPB) exposure methods are disclosed that resolve the problem of aberrations produced by an image-adjustment lens and the problem of limitations in the speeds in which stage-correction mechanisms can be adjusted. Adjustments of stage-correction mechanisms and image-adjustment lenses are optimized in any of various combinations depending upon exposure conditions, pattern configuration, etc. Image rotation and defocusing in CPB microlithography can be corrected by moving the reticle stage and substrate stage using respective stage-control and correction devices. Alternatively or in addition, adjustments can be made by controllably adjusting a deflector and/or an image-adjustment lens. Whenever corrections are required over a wide correction range and a relatively slow correction speed is acceptable, corrections can be made using a stage-correction mechanism.

Abstract: In order to make it possible to suppress projection errors in the portions of patterns which are connected together, in a method of pattern projection which includes a process of making a pattern of a beam of charged particle, in which a beam of charged particles is irradiated upon a small region upon a mask and the beam of charged particles is caused to change by the influence of pattern which is provided on the selected small regions, a process of projection in which the patterns of the beam of charged particles are projected upon a certain portion of a projection reception region which is defined upon a sensitive plate, a process of scanning in which the small region and the certain portion are selected in sequence, the patterns of the selected small regions are projected upon the selected certain portions and connected in sequence, a process of irradiation amount reduction is performed, during the scanning process, the amount of irradiation by the beam of charged particles of the peripheral portion of the

Abstract: 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.

Abstract: Charged-particle-beam projection-microlithography apparatus and methods are disclosed for transferring a reticle pattern image to a substrate using a charged-particle beam. The apparatus comprises, along an optical axis in the trajectory direction of the charged-particle beam, a beam emitter for emitting the charged-particle beam toward the mask, a beam shaper for shaping the charged-particle beam so as to have a square or rectangular transverse profile and deflectors for directing the charged-particle beam onto the mask. If the beam shaper creates a charged-particle beam having a rectangular transverse profile, the deflectors of the pattern-transfer apparatus of the present invention operate so that the longer sides of the transverse profile of the charged-particle beam extend in a direction perpendicular to the scanning direction.

Abstract: Electron-beam projection-microlithography apparatus are disclosed for transferring a reticle pattern image to a substrate using an electron beam. The apparatus includes, along an optical axis in the trajectory direction of the electron beam, an electron gun, a field-limiting aperture for limiting the field of the electron beam emitted from the electron gun. A reticle can be positioned to receive and selectively transmit an electron beam transmitted by the field-limiting aperture.

Abstract: A pattern transfer apparatus in which a part or all of a plurality of small areas on a mask are sequentially irradiated with a charged particle beam to transfer an image of a pattern provided in each of the irradiated small areas onto a radiation-sensitive substrate, e.g., a wafer. A pattern distribution condition is evaluated for each small area, and an image-formation condition of the pattern image with respect to the radiation-sensitive substrate is adjusted for each small area on the basis of predetermined information including a result of the evaluation.

Abstract: Apparatus and methods are disclosed for increasing the throughput of a charged-particle-beam exposure apparatus. The apparatus comprises an exposure-processing chamber in which exposure of individual sensitive substrates is performed using a charged-particle beam under preset vacuum and temperature conditions. A load-lock chamber, connected to the exposure-processing chamber by a gate valve, is used to bring the sensitive substrate from atmospheric conditions to a vacuum condition in preparation for transport into the exposure-processing chamber. Means are provided for adjusting the temperature of the sensitive substrates so that, upon entry of the sensitive substrate into the exposure-processing chamber, the temperature of the sensitive substrate matches an interior temperature of the exposure-processing chamber.

Abstract: Apparatus are disclosed for performing microlithography using a charged-particle beam and a mask partitioned into multiple subfields to be transferred sequentially to a sensitive substrate. The apparatus comprise a charged-particle-beam illumination system, a charged-particle-beam projection system, and a beam-characteristics correction system situated between the charged-particle-beam source and the substrate. The beam-characteristics correction system is energizable to serve as either an illumination-characteristics correction means (e.g., a first set of coils situated between the source and the mask) or an imaging-characteristics correction means (a first or second set of coils situated between the mask and the substrate).

Abstract: The apparatus and methods of the present invention provide for the precise measurement and correction of pattern formation characteristics, such as the reduction factor and the rotation angle of projected images.

Abstract: Disclosed herein is a pattern transfer method wherein a beam transmitting portion which transmits a charged particle beam and a beam limiting portion which scatters or absorbs the charged particle beam to a greater extent than the beam transmitting portion are disposed in a pattern area of a mask according to a pattern to be transferred onto a radiation-sensitive substrate. The pattern area is irradiated with the charged particle beam, and at least a part of the charged particle beam passing through the mask is led to the substrate to transfer the pattern onto the substrate. When the pattern area is irradiated with the charged particle beam, the dose of charged particle beam applied per unit area of the beam limiting portion is reduced to a quantity smaller than the dose of charged particle beam applied per unit area of the beam transmitting portion.

Abstract: By causing a mask and a wafer to continuously move once or more and irradiating a plurality of small areas contained within a specific range of the mask in time sequence with a charged particle beam during each such continuous movement, the pattern in each small area is selectively projected onto a projection target area contained within a specific range of the wafer. The pattern to be projected onto one projection target area is divided and formed on a plurality of specific small areas contained within a specific range of the mask, and when the reduction ratio of the pattern projected from the mask onto the wafer is at 1/M, the continuous movement speed of the mask is set to be (N.times.