Abstract: A charged particle beam optical system is provided with a plurality of irradiation optical systems each of which irradiates an object W with a charged particle beam EB, the plurality of irradiation optical system includes a first irradiation optical system and a second irradiation optical system that generates a second magnetic field having a characteristics different from a characteristics of a first magnetic field generated by the first irradiation optical system.

Abstract: A charged particle beam optical system is provided with a plurality of irradiation optical systems each of which irradiates an object W with a charged particle beam EB, the plurality of irradiation optical system includes a first irradiation optical system and a second irradiation optical system that generates a second magnetic field having a characteristics different from a characteristics of a first magnetic field generated by the first irradiation optical system.

Abstract: Methods and devices are disclosed for evaluating image performance in a charged-particle-beam (CPB) microlithography apparatus. In the disclosed method, multiple knife-edge reference marks are defined by a plate positioned at an image plane. The reference marks are illuminated by measurement beamlets formed by an upstream subfield. The beamlets are scanned over the reference marks to produce a series of beam-current transmissions. Each beam-current transmission corresponds to a single beamlet being scanned over a corresponding reference mark. The beam-current transmissions are exclusive of one another. The series of transmissions is then detected and analyzed. The knife-edge reference marks may be positioned on the plate so that the relative distance between the reference marks and the corresponding beamlets progressively increases for each successively scanned mark. A dummy beam also may be defined on the upstream subfield.

Abstract: Methods and devices are disclosed for evaluating image performance in a charged-particle-beam (CPB) microlithography apparatus. In the disclosed method, multiple knife-edge reference marks are defined by a plate positioned at an image plane. The reference marks are illuminated by measurement beamlets formed by an upstream subfield. The beamlets are scanned over the reference marks to produce a series of beam-current transmissions. Each beam-current transmission corresponds to a single beamlet being scanned over a corresponding reference mark. The beam-current transmissions are exclusive of one another. The series of transmissions is then detected and analyzed. The knife-edge reference marks may be positioned on the plate so that the relative distance between the reference marks and the corresponding beamlets progressively increases for each successively scanned mark. A dummy beam also may be defined on the upstream subfield.

Abstract: Methods and devices are disclosed for evaluating the imaging performance of a charged-particle-beam (CPB) microlithography system. An embodiment of such a device includes a knife-edged pattern region defining multiple knife-edged apertures that are longitudinally extended. Each aperture includes a respective knife-edge on each of its two respective longitudinal edges. A charged particle beam having a rectangular transverse profile is scanned across the apertures such that the beam reaches a knife-edge on an adjacent aperture before the previous knife-edge exhibits radiation-induced deterioration. Furthermore, each of the knife-edges can be swept multiple times by respective beam scans performed at different locations in the longitudinal direction. Hence, measurements can be performed many times (e.g., hundreds of times) using a single knife-edged pattern region.

Abstract: Methods and devices are disclosed for evaluating the imaging performance of a charged-particle-beam (CPB) micro lithography apparatus. A measurement mark is situated at an object plane, a knife-edged reference mark is situated at an image plane, and a beam-limiting diaphragm, defining a beam-limiting aperture, is situated downstream of the reference mark. The knife-edged reference mark is defined as a respective aperture in a scattering membrane. Passage of a charged particle beam through the measurement mark produces a beamlet that is scanned over the knife-edged reference mark. Charged particles of the beamlet passing through the reference mark are not scattered, while charged particles of the beamlet passing through the membrane are forward scattered. The diameter of the beam-limiting aperture can be established such that an axial angle of the beam-limiting aperture as measured at the knife-edge is slightly greater than a convergent angle of the beamlet at a projection lens.

Abstract: Methods and devices are provided for performing adjustments of illumination uniformity obtained from a charged-particle illumination-optical system as used, e.g., in a charged-particle-beam (CPB) microlithography apparatus. The adjustments are based on measurements of illumination-beam current density. The device includes an aperture plate (desirably a silicon membrane), defining a tiny measurement aperture (desirably about 1 &mgr;m diameter), mounted on the reticle stage at the reticle plane. The illumination beam is scanned over the aperture. Charged particles of the beam passing through the aperture are directed to a beam-current detector on or at the substrate stage. The membrane desirably has a thickness of about 1 to 3 &mgr;m. The measurement aperture allows the distribution of current density of the illumination beam to be measured highly accurately.

Abstract: Methods and devices are provided for performing adjustments of illumination uniformity obtained from a charged-particle illumination-optical system as used, e.g., in a charged-particle-beam (CPB) microlithography apparatus. The adjustments are based on measurements of illumination-beam current density. The device includes an aperture plate (desirably a silicon membrane), defining a tiny measurement aperture (desirably about 1 &mgr;m diameter), mounted on the reticle stage at the reticle plane. The illumination beam is scanned over the aperture. Charged particles of the beam passing through the aperture are directed to a beam-current detector on or at the substrate stage. The membrane desirably has a thickness of about 1 to 3 &mgr;m. The measurement aperture allows the distribution of current density of the illumination beam to be measured highly accurately.

Abstract: Methods and devices are disclosed for evaluating the imaging performance of a charged-particle-beam (CPB) microlithography system. An embodiment of such a device includes a knife-edged pattern region defining multiple knife-edged apertures that are longitudinally extended. Each aperture includes a respective knife-edge on each of its two respective longitudinal edges. A charged particle beam having a rectangular transverse profile is scanned across the apertures such that the beam reaches a knife-edge on an adjacent aperture before the previous knife-edge exhibits radiation-induced deterioration. Furthermore, each of the knife-edges can be swept multiple times by respective beam scans performed at different locations in the longitudinal direction. Hence, measurements can be performed many times (e.g., hundreds of times) using a single knife-edged pattern region.

Abstract: Methods and devices are disclosed for evaluating image performance in a charged-particle-beam (CPB) microlithography apparatus. In the disclosed method, multiple knife-edge reference marks are defined by a plate positioned at an image plane. The reference marks are illuminated by measurement beamlets formed by an upstream subfield. The beamlets are scanned over the reference marks to produce a series of beam-current transmissions. Each beam-current transmission corresponds to a single beamlet being scanned over a corresponding reference mark. The beam-current transmissions are exclusive of one another. The series of transmissions is then detected and analyzed. The knife-edge reference marks may be positioned on the plate so that the relative distance between the reference marks and the corresponding beamlets progressively increases for each successively scanned mark. A dummy beam also may be defined on the upstream subfield.

Abstract: Highly durable reference marks are disclosed as used, in charged-particle-beam microlithography, for performing accurate beam-position sensing and alignment. An exemplary reference mark comprises a mark substrate made of a low-thermal-expansion material, on which is formed a pattern of mark elements for receiving an incident charged particle beam. In the vicinity of the pattern, between the mark elements and the substrate, is a layer of an electrically conductive material connected to electrical ground. The conductive material has a thickness sufficient to block penetration through the layer of conductive material of incident charged particles. Charged particles absorbed by the layer are shunted to ground.

Abstract: Evaluation methods are disclosed for evaluating the image-forming performance of charged-particle-beam microlithography systems, especially with regard to astigmatism and focus. In an embodiment, a subfield containing an evaluation pattern is subdivided into multiple regions. In the various regions, the respective line-and-space (L/S) pattern elements are oriented such that the elements in one region extend in a direction that intersects the direction, in the object plane of orientation of the pattern element in another region. The evaluation pattern is transferred lithographically to a resist film on a substrate. The developed resist, when observed at a magnification at which individual L/S pattern elements are not resolved, reveals a “shadow region” having a particular profile. The profile is a function of one or more parameters (e.g., astigmatism and focus) of image-forming performance.

Abstract: Methods and devices are provided for performing adjustments of illumination uniformity obtained from a charged-particle illumination-optical system as used, e.g., in a charged-particle-beam (CPB) microlithography apparatus. The adjustments are based on measurements of illumination-beam current density. The device includes an aperture plate (desirably a silicon membrane), defining a tiny measurement aperture (desirably about 1 &mgr;m diameter), mounted on the reticle stage at the reticle plane. The illumination beam is scanned over the aperture. Charged particles of the beam passing through the aperture are directed to a beam-current detector on or at the substrate stage. The membrane desirably has a thickness of about 1 to 3 &mgr;m. The measurement aperture allows the distribution of current density of the illumination beam to be measured highly accurately.

Abstract: Methods and devices are disclosed for evaluating the imaging performance of a charged-particle-beam (CPB) micro lithography apparatus. A measurement mark is situated at an object plane, a knife-edged reference mark is situated at an image plane, and a beam-limiting diaphragm, defining a beam-limiting aperture, is situated downstream of the reference mark. The knife-edged reference mark is defined as a respective aperture in a scattering membrane. Passage of a charged particle beam through the measurement mark produces a beamlet that is scanned over the knife-edged reference mark. Charged particles of the beamlet passing through the reference mark are not scattered, while charged particles of the beamlet passing through the membrane are forward scattered. The diameter of the beam-limiting aperture can be established such that an axial angle of the beam-limiting aperture as measured at the knife-edge is slightly greater than a convergent angle of the beamlet at a projection lens.

Abstract: Methods and devices are provided for performing adjustments of illumination uniformity obtained from a charged-particle illumination-optical system as used, e.g., in a charged-particle-beam (CPB) microlithography apparatus. The adjustments are based on measurements of illumination-beam current density. The device includes an aperture plate (desirably a silicon membrane), defining a tiny measurement aperture (desirably about 1 &mgr;m diameter), mounted on the reticle stage at the reticle plane. The illumination beam is scanned over the aperture. Charged particles of the beam passing through the aperture are directed to a beam-current detector on or at the substrate stage. The membrane desirably has a thickness of about 1 to 3 &mgr;m. The measurement aperture allows the distribution of current density of the illumination beam to be measured highly accurately.

Abstract: Charged-particle-beam (CPB) projection-exposure methods, apparatus, and reticles are disclosed that can be used for efficiently and accurately measuring and correcting various reticle distortions. A reticle is segmented into multiple exposure units grouped into stripes. In a stripe, peripheral exposure units define second alignment marks for measuring reticle distortion arising from loading the reticle in the CPB projection-exposure apparatus. The reticle includes struts arranged into a grillage separating individual exposure units from one another. The struts define first alignment marks for measuring reticle distortion arising from reticle fabrication. The positions of the first alignment marks are measured in advance to obtain distortion data for each respective exposure unit. After loading the reticle in the CPB projection-exposure apparatus, the positions of the second alignment marks 51 are measured to obtain data on reticle distortion arising from loading the reticle.

Abstract: A charged particle beam transfer mask (6) has a plurality of subfields (8) each of which having a different pattern density. The charged particle beam transfer mask (6) divide-irradiates a charged particle beam (5) for each of the subfields (8) and reduce-transfers a pattern onto a sensitive substrate. The charged particle beam transfer mask (6) corrects the differences in the de-focus amounts (3) caused by Coulomb effect due to the different pattern densities when the pattern is transferred for each of the subfields (8) so as to eliminate the differences in the de-focus amounts (3) caused by Coulomb effect by pre-varying the position (height) of each of the subfields (8) in the optical axis direction.

Abstract: Segmented reticles are disclosed for used with charged-particle-beam projection-microlithography apparatus. Such reticles comprise multiple mask subfields and a support grid, of intersecting struts, having an upstream-facing surface and a downstream-facing surface. Alignment marks are situated on the upstream- or downstream-facing surface. The projection-microlithography apparatus comprise a beam source, an illumination system, and a subfield-selection deflector. A second deflector downstream of the reticle further deflects the beam to impart a change in a parameter of the beam to correct reticle distortion. A correction-optical system can further change one or more characteristics of the beam downstream of the reticle to correct reticle distortion. A detector determines actual alignment-mark positions relative to ideal positions, and a controller calculates therefrom a required change to be imparted to the charged particle beam to correct the reticle distortion.