JP2011023126A - Charged particle beam irradiating device, lithography apparatus, analyzer microscope, charged particle beam emitter, and lens unit for charged particle beam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of spherical aberration on a lens to emit charged particle beam elements precisely onto an object. <P>SOLUTION: A lithography apparatus includes an electron beam emitting unit which emits a plurality of electron beam elements from a plurality of two-dimensionally arranged emission sources, and an electron optics system which guides the electron beam elements to a board. The electron optics system has an electrostatic lens 41 which generates a potential rotationally symmetric with respect to an axis J1 parallel with an emission direction. When a pattern is drawn, a group of the electron beam elements emitted in ring shapes around the axis J1 are emitted sequentially as ring diameters are changed, and a field generated by the electrostatic lens 41 to act on the group of the electron beam elements is changed depending on each ring diameter so that the group of the electron beam elements pass through the same position on the axis J1 regardless of ring diameter variations. This prevents the occurrence of spherical aberration on the electrostatic lens 41, thus allows the electron beam elements to be emitted precisely onto the board. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a charged particle beam irradiation apparatus that irradiates a charged particle beam onto an object, a drawing apparatus and an analysis microscope having the charged particle beam irradiation apparatus, a charged particle beam emission apparatus that emits a charged particle beam, and charged particles The present invention relates to a lens device for a line.

  With the miniaturization of semiconductor elements, demands for shorter wavelengths and higher quality of the exposure light source are increasing. In recent years, an immersion exposure apparatus that performs exposure in a state where a liquid is filled between a projection lens and a semiconductor substrate has been widely used, but there are many practical problems in miniaturization by the immersion exposure method. For example, it is possible to overcome these problems by reducing the light intensity at the resist surface due to the absorption of light by the liquid with a high refractive index, the resulting decrease in throughput, thermal decomposition of the liquid, generation of bubbles, etc. High refractive index liquids are central to R & D goals. On the other hand, at the basic research level, for example, semiconductor devices having a size of less than 15 nanometers (nm) are prototyped by an electron beam exposure method using an electron beam. The wavelength of the electron beam can be controlled by an acceleration voltage, and the electron beam is a wave that can easily obtain a wavelength of less than 1 nm.

  As a drawing apparatus that draws a pattern using an electron beam, a method of drawing a pattern by emitting an electron beam from an electron source and scanning the irradiation position of the electron beam on a substrate is generally used. However, in the above apparatus for drawing a pattern by so-called one-stroke writing, it takes a lot of time to draw the pattern on the entire substrate, and the manufacturing cost of the semiconductor device increases, so that it is put to practical use as a semiconductor manufacturing apparatus. Not.

  Therefore, in recent years, an electron beam (actually, it can be regarded as a set of electron beam elements since it is an electron beam irradiated over a wide range at once) is applied to a reticle having holes corresponding to a pattern to be formed. A drawing apparatus that draws a pattern on a substrate by irradiating the substrate with an electron beam that has been irradiated and passed through a hole has been proposed. For example, Patent Document 1 discloses a variable axis lens in such a drawing apparatus. (A method known as the PREVAIL (Projection Reduction Exposure with Variable Axis Immersion Lenses) method) is disclosed. In the PREVAIL type drawing apparatus, by substantially shifting the optical axis on the reticle, the electron beam can travel along the optical axis at a position on the reticle that is off the original optical axis of the optical system. It becomes possible. That is, a paraxial ray can be obtained even in a region deviating from the central axis of the device, and plays a role in reducing aberrations.

  On the other hand, in Patent Document 2, a two-dimensional drawing pattern is formed by causing a two-dimensional light pattern to enter one end of a bundle of a plurality of microchannels and emitting an electron beam array based on the light pattern from the other end. Has been disclosed. In Patent Document 3, an electron beam array is irradiated onto a sample to be observed from a plurality of microchannels similar to the above, and secondary electrons are detected by a secondary electron detector to generate an electron microscope image. In this case, the same number of two-dimensional patterns as the number of pixels included in the observation region are set in time series so as to be independent two-dimensional patterns, and the time-series two-dimensional pattern and the secondary electron detection are performed. A technique for obtaining an electron microscope image having a high S / N ratio based on a time-series detection signal detected by the instrument is disclosed.

US Pat. No. 5,466,904 International Publication No. 2006/123447 Pamphlet JP 2007-141797 A

  By the way, as in the devices disclosed in Patent Documents 1 to 3, an electron beam (actually, it is a set of a plurality of electron beam elements) in a relatively large area on the object in one drawing operation. Of the plurality of electron beam elements incident in parallel to the optical axis in the lens of the electron optical system, the electron beam element in the vicinity of the optical axis (shifted optical axis in the PREVAIL type drawing apparatus) is the lens. Spherical aberration, which is a phenomenon in which the position where the electron beam element away from the optical axis passes through the optical axis due to the action of the lens, is caused by the action of the lens. This makes it difficult to accurately irradiate the electron beam element onto the object. Such a problem also occurs when a charged particle beam other than an electron beam is irradiated onto an object. In an electron microscope, an electron beam exposure apparatus, etc., the resolution is dominantly determined by aberration rather than wavelength. There are many. Moreover, in order to irradiate a charged particle beam element on a target object with higher accuracy, it is also required to emit a charged particle beam element that travels at a constant speed from an emitting unit.

  The present invention has been made in view of the above problems, and it is a main object to prevent spherical aberration from occurring in a lens and irradiate a charged particle beam element onto an object with high accuracy, at a constant speed. Another object is to emit a traveling charged particle beam element.

  The invention according to claim 1 is a charged particle beam irradiation apparatus for irradiating a target with a charged particle beam, and the intensity from a plurality of emission sources two-dimensionally arranged on a plane perpendicular to the emission direction. A plurality of charged particle beam emitting units that respectively emit a plurality of charged particle beam elements that can be controlled and controlled; and a lens that generates a rotationally symmetric potential with respect to a central axis parallel to the emission direction. A charged particle optical system that guides particle beam elements onto an object and a group of charged particle beam elements that are emitted in a ring shape around the central axis are sequentially emitted from the charged particle beam emitting unit while changing the ring radius. A field acting on the charged particle beam element group by the lens according to the ring radius so that the charged particle beam element group passes through the same position on the central axis regardless of the ring radius. And a further control unit.

  Invention of Claim 2 is a charged particle beam irradiation apparatus of Claim 1, Comprising: The path | route of the said charged particle beam element group which injects into the said lens is parallel to the said central axis, The said charge A particle optical system generates a rotationally symmetric potential with respect to the central axis, and a path of the charged particle beam element group that has passed through the same position on the central axis is parallel to the central axis. And a lens for changing a field acting on the charged particle beam element group according to the ring radius.

  A third aspect of the present invention is the charged particle beam irradiation apparatus according to the first or second aspect, wherein the charged particle beam emitting portions are two-dimensionally arranged on a plane perpendicular to the emitting direction. A charged particle beam generation unit configured to generate the plurality of charged particle beam elements by the plurality of emission sources, and at least one aperture plate in which a plurality of openings are formed in the same arrangement as the plurality of emission sources. Are arranged in the emission direction and pass through the direction restriction unit and the direction restriction unit for restricting the traveling direction of the plurality of charged particle beam elements emitted from the charged particle beam generation unit to a certain direction. A pair of speed uniformizing sections that uniformize the traveling speed of the plurality of charged particle beam elements, and the speed uniformizing section includes a plurality of openings formed in the same arrangement as the plurality of emission sources. Electrode pairs, and the pair of electrode plates A portion around the two apertures is one electrostatic lens, and the two apertures of the aperture plate farthest from the charged particle beam generation unit of the at least one aperture plate in the emission direction. A shift electrostatic lens array that partially overlaps one of the openings, and a plurality of openings are formed in the same arrangement as the plurality of emission sources, and the action of each electrostatic lens of the shift electrostatic lens array A pair of electrode plates in which a part of the received charged particle beam element has an intermediate aperture plate that passes through any of the plurality of openings and a plurality of openings formed in the same arrangement as the plurality of emission sources. A portion around the two openings corresponding to each other of the pair of electrode plates is an electrostatic lens, and the front focal point of each electrostatic lens is the opening of any one of the intermediate aperture plates. During ~ And a correcting electrostatic lens array becomes.

  A fourth aspect of the present invention is the charged particle beam irradiation apparatus according to the third aspect, wherein the speed uniformizing unit includes the shift electrostatic lens array, the intermediate aperture plate, and the correction electrostatic lens array. At least one velocity equalizing unit having a structure similar to that of the first velocity equalizing unit that is a combination, arranged in the emission direction, and each of the shift electrostatic lens arrays of each of the at least one velocity equalizing unit is mutually connected Two corresponding apertures overlap at least partially with any aperture of the correction electrostatic lens array of the velocity uniformizing unit immediately before in the emission direction.

  The invention according to claim 5 is the charged particle beam irradiation apparatus according to claim 4, wherein the at least one speed uniformizing unit is two or more speed uniformizing units, and the first speed uniformizing unit. In addition, the path of each charged particle beam element by the two or more velocity equalizing units is approximately spiral along the emission direction.

  Invention of Claim 6 is a charged particle beam irradiation apparatus in any one of Claim 3 thru | or 5, Comprising: The said charged particle beam production | generation part has the light emission part which radiate | emits the spatially modulated light, Each of the plurality of charged particle beam elements has a plurality of microchannels each extending in the emission direction and amplifying electrons therein as the plurality of emission sources, and is caused by incidence of light from the light emission unit. The conversion part which radiates | emits.

  The invention described in claim 7 is a drawing apparatus that draws a pattern by irradiating an object with a charged particle beam, the charged particle beam irradiation apparatus according to any one of claims 1 to 6, and drawing data. The charged particle beam irradiation apparatus controls irradiation of the charged particle beam onto the object in accordance with the drawing data.

  The invention described in claim 8 is an analytical microscope that acquires an image of an object by irradiating the object with a charged particle beam, and the charged particle beam irradiation apparatus according to any one of claims 1 to 6 And a detector that detects a particle beam or an electromagnetic wave emitted from an object by irradiation with a charged particle beam.

  The invention according to claim 9 is a charged particle beam emitting device for emitting a charged particle beam, wherein a plurality of charged particle beams are emitted from a plurality of emission sources arranged two-dimensionally on a plane perpendicular to the emission direction. A charged particle beam generator that emits while generating elements, and at least one aperture plate in which a plurality of openings are formed in the same arrangement as the plurality of emission sources, arranged in the emission direction, and the charge A direction limiting unit that limits the traveling direction of the plurality of charged particle beam elements emitted from the particle beam generating unit to a certain direction, and a uniform traveling speed of the plurality of charged particle beam elements that have passed through the direction limiting unit And a pair of electrode plates having a plurality of openings formed in the same arrangement as the plurality of emission sources, and the pair of electrode plates The area around two openings corresponding to each other is one electrostatic Shift electrostatic lens in which the two openings partially overlap with any one of the aperture plates of the at least one aperture plate farthest from the charged particle beam generation unit in the emission direction. The array and the plurality of openings are formed in the same arrangement as the plurality of emission sources, and a part of the charged particle beam element subjected to the action of each electrostatic lens of the shift electrostatic lens array includes the plurality of apertures. A pair of electrode plates having a plurality of openings formed in the same arrangement as the plurality of emission sources, and the pair of electrode plates corresponding to each other. A portion around the two apertures constitutes one electrostatic lens, and includes a correction electrostatic lens array in which the front focal point of each electrostatic lens is the center of one of the apertures of the intermediate aperture plate.

  The invention according to claim 10 is a lens apparatus for a charged particle beam, each of which is centered on a central axis, and a plurality of ring members arranged along the central axis, and perpendicular to the central axis In the spaces in the plurality of ring members through which the plurality of charged particle beam elements that are emitted from a plurality of emission sources that are two-dimensionally arranged on a flat surface and incident on the plurality of ring members pass, A voltage source for applying a potential to the plurality of ring members so as to generate a potential equivalent to a potential generated by a lens sufficiently larger than the ring member.

  According to the first to eighth and tenth aspects of the present invention, spherical aberration can be prevented from occurring in the lens, and the charged particle beam element can be accurately irradiated onto the object.

  According to the second aspect of the present invention, spherical aberration is prevented from occurring in the two lenses constituting the double-sided telecentric optical system, so that the coordinate in the optical axis direction of the irradiation region of the charged particle beam element group on the object is obtained. It is possible to irradiate the charged particle beam element with high accuracy while keeping the magnification constant even if changes.

  In the inventions according to claims 3 to 6 and claim 9, the charged particle beam element traveling at a constant speed in a constant direction can be emitted.

  Further, in the inventions of claims 4 and 5, in the charged particle beam emitting portion, the speed of the charged particle beam element can be made more constant, and in the invention of claim 7, the pattern can be drawn with high accuracy, In invention of Claim 8, the image of a target object can be acquired accurately.

It is a figure which shows the structure of a drawing apparatus. It is a perspective view which shows MCP. It is a figure which shows the structure of a part of electron beam restriction | limiting part. It is a figure which expands and shows a part of speed equalization unit. It is a figure which shows the position of the electrostatic lens of a some correction | amendment electrostatic lens array. It is a perspective view which shows MCP. It is a perspective view which shows MCP and an electrostatic lens. It is a figure which shows the track | orbit of an electron beam element group. It is a figure which shows the track | orbit of an electron beam element group. It is a figure which shows the flow of the process which determines the voltage provided to an electrostatic lens. It is a figure which shows the track | orbit of an electron beam element group. It is a figure which shows the potential which acts on the electron beam element group of each ring radius. It is a figure which shows the pattern on a reference board | substrate. It is sectional drawing of a reference board | substrate. It is a figure which shows an electron beam element group. It is a figure which shows an electron beam irradiation matrix. It is a figure which shows the electrostatic lens in the drawing apparatus of a comparative example. It is a figure which shows the electrostatic lens in the drawing apparatus of a comparative example. It is a figure which shows the track | orbit of the electron beam element in the drawing apparatus of a comparative example. It is a figure which shows the track | orbit of the electron beam element in the drawing apparatus of a comparative example. It is a figure which shows the electrostatic lens in the drawing apparatus of a comparative example. It is a perspective view which shows a lens apparatus. It is a figure which shows the other example of an electron beam emission part.

  FIG. 1 is a diagram showing a configuration of a drawing apparatus 1 according to an embodiment of the present invention. The drawing apparatus 1 irradiates a substrate 9 with an electron beam and draws a pattern on the substrate 9 (the electron beam resist 92), and is also called an electron beam exposure apparatus. A thin film 91 such as a metal thin film, a semiconductor film, and an insulating film and an electron beam resist 92 are sequentially formed on one main surface of the substrate 9.

  The drawing apparatus 1 includes a stage 21 on which a substrate 9 is placed, an electron beam emitting unit 3 that emits an electron beam, and an electron beam from the electron beam emitting unit 3 along a predetermined central axis J1. The stage 21 is placed on the main surface of the substrate 9 with respect to the electron optical system 4 that leads to the electron beam detector 4, the detector 5 that detects secondary electrons emitted from the substrate 9 by the electron beam irradiation, the electron beam emitting unit 3 and the electron optical system 4. A moving mechanism 22 that moves along the line and a control unit 6 that performs overall control of the drawing apparatus 1 are provided. The control unit 6 includes an electron emission control unit 61 that controls the emission of the electron beam, a light pattern generation unit 62 that generates a light pattern signal described later when the electron beam is emitted, and the electrostatic lenses 41 and 42 of the electron optical system 4. The electrostatic lens control unit 63 to be controlled, the applied voltage calculation unit 64 for obtaining the voltage to be applied to the electrostatic lenses 41 and 42, the detection signal processing unit 65 for processing the signal from the detector 5, and the moving mechanism 22 are controlled. A stage drive controller 66 is provided. The electron emission control unit 61 stores a drawing unit 611 that stores drawing data 612 indicating a pattern to be drawn on the substrate 9, and a code that generates a predetermined signal when an image on the substrate is acquired by an operation described later. A signal generation unit 613 is provided.

The drawing apparatus 1 further includes a chamber body 11 that accommodates therein a stage 21, an electron beam emitting unit 3, an electron optical system 4, a detector 5, and a moving mechanism 22, and the interior of the chamber body 11 is a vacuum pump (not shown). For example, the pressure is reduced to, for example, 10 ⁻⁶ Torr (133.3 × 10 ⁻⁶ Pascal (Pa)) or less (in this embodiment, 10 ⁻⁸ Torr).

  As shown in FIG. 1, the electron beam emitting unit 3 is provided near the top of the chamber body 11 and emits a spatially modulated light, and a conversion that emits an electron beam according to the incident light. And an electron beam limiting section 34 that limits the electron beam incident on the electron optical system 4 to a constant traveling direction and traveling speed. The light emitting unit 31 includes, for example, a light source that emits light and a spatial light modulation device such as a liquid crystal shutter, and the light (two-dimensional light pattern) modulated according to the pattern to be drawn is the central axis J1. Is emitted in the emission direction parallel to the. The light emitting unit 31 may be one that modulates light from a light source using a DMD (digital micromirror device) or a plurality of light sources that are two-dimensionally arranged.

  The conversion unit 32 includes a thick disc-shaped microchannel plate (hereinafter simply referred to as “MCP”) 33, and the light emitted from the light emitting unit 31 is a photoelectric provided on the light emitting unit 31 side of the MCP 33. Incident on the film 332. The photoelectric film 332 spreads in a direction perpendicular to the central axis J1, and in practice, an image of the exit surface of the light exit portion 31 is formed on the photoelectric film 332 by the optical lens 311 and the incident light is converted into electrons. And released into the MCP 33.

  FIG. 2 is a perspective view showing a part of the MCP 33 by breaking it. As shown in FIG. 2, the MCP 33 has a plurality of microchannels 331 each extending in the emission direction (that is, the direction of the central axis J1) and amplifying electrons inside, and a plurality of microchannels 331 parallel to each other. Are densely arranged in a direction perpendicular to the emission direction while the central axis J1 (see FIG. 1) is arranged in the center. A semiconductor film that emits secondary electrons by electron collision is formed on the inner peripheral surface of each microchannel 331. In the conversion section 32 of FIG. The electron beam element is emitted from the other end side of each microchannel 331 by being incident on one end side of the microchannel via the photoelectric film 332. In FIG. 2, the electron beam element travels from the MCP 33 toward the upper side (more precisely, the upper left side) of FIG. The electron beam element from the MCP 33 travels downward in FIG. 1 (the same applies to FIGS. 3, 4, 6, 7, and 22 described later). A plurality of electron beam elements emitted from the conversion unit 32 due to the incidence of light from the light emitting unit 31 are incident on the electron beam limiting unit 34.

  As described above, in the drawing apparatus 1, each microchannel 331 is an emission source of an electron beam element, and a plurality of electrons are emitted from a plurality of emission sources that are two-dimensionally arranged on a plane perpendicular to the emission direction. An electron beam generating unit that emits while generating beam elements is realized by the light emitting unit 31 and the conversion unit 32. The MCP 33 is produced by forming a plurality of through holes (microchannels) mainly composed of lead glass and extending in a direction perpendicular to the main surface, and forming electrodes on both surfaces. The microchannels 331 in the MCP 33 are not necessarily arranged regularly.

  FIG. 3 is a diagram showing a partial configuration of the electron beam limiting unit 34. As shown in FIG. 3, the electron beam restriction unit 34 includes a direction restriction unit 35 that restricts (collimates) a traveling direction of the plurality of electron beam elements emitted from the MCP 33, and a direction restriction unit 35. A speed uniformizing unit 36 for uniformizing the traveling speed of the plurality of electron beam elements that have passed is provided.

  The direction restricting portion 35 has a plurality of aperture plates 351 extending in the direction perpendicular to the emission direction (longitudinal direction in FIG. 3) arranged in the emission direction, and each aperture plate 351 has a plurality of openings 352. It is formed in the same arrangement as the plurality of microchannels 331 (see FIG. 2). Each aperture 352 of the aperture plate 351 overlaps any one of the microchannels 331 of the MCP 33 in the emission direction, and in the electron beam element emitted from each microchannel 331, a plurality of aperture plates 351 corresponding to each other are arranged. Only the component (electrons) that has passed through the opening 352 is guided to the speed uniformizing unit 36. In FIG. 3, the traveling direction of the component of the electron beam element is indicated by an arrow labeled B2.

  For example, when the MCP 33 is manufactured, the plurality of aperture plates 351 are obtained by slicing a lead glass plate immediately after forming the plurality of through holes along the main surface, and depositing a metal film on the surface as necessary. It is manufactured (the same applies to the shift electrostatic lens array 37, the intermediate aperture plate 38, and the correction electrostatic lens array 39 described later). In such an aperture plate 351, the relative positions of the plurality of openings 352 on the main surface thereof are the same as the relative positions of the plurality of microchannels 331 on the plane perpendicular to the central axis J1 (that is, the plurality of openings). 352 has the same arrangement as the plurality of microchannels 331.) The size of each opening 352 is also the same as that of the microchannel 331, and the entire opening 352 of the aperture plate 351 is the opening of any one of the microchannels 331 of the MCP 33. It is possible to accurately overlap the whole and the emission direction. In the present embodiment, no voltage is applied between the plurality of aperture plates 351, but a voltage may be applied between the plurality of aperture plates 351 depending on the design of the drawing apparatus 1.

  The speed uniformizing unit 36 extracts a plurality of speed uniformizing units 360 (one in FIG. 3) that extracts only components (electrons) having a substantially constant traveling speed in the plurality of electron beam elements that have passed through the direction limiting unit 35. The speed uniformizing unit is denoted by reference numeral 360a.), And a plurality of speed uniformizing units 360, 360a are arranged in the emission direction. Each of the speed uniformizing units 360 and 360a includes a shift electrostatic lens array 37 in which a plurality of electrostatic lenses that form electric fields acting on a plurality of electron beam elements are arranged, and each electrostatic lens of the shift electrostatic lens array 37. The intermediate aperture plate 38 through which only a part of the electron beam elements subjected to the above action passes, and the traveling direction of each electron beam element that has passed through the intermediate aperture plate 38 in the emission direction parallel to the central axis J1 A correction electrostatic lens array 39 is provided.

  FIG. 4 is an enlarged view showing a part of the first speed equalizing unit 360a adjacent to the direction limiting unit 35. As shown in FIG. The shift electrostatic lens array 37 has a pair of electrode plates 371 having a plurality of openings 372 formed in the same arrangement as the plurality of microchannels 331 (see FIG. 2) (in FIG. Only one opening 372 of 371 is shown, as is the case with the intermediate aperture plate 38 and the correction electrostatic lens array 39.) The pair of electrode plates 371 are connected to a voltage source (not shown). Each opening 372 of one electrode plate 371 is exactly overlapped with one of the openings 372 of the other electrode plate 371 in the emission direction (vertical direction in FIG. 4), and the pair of electrode plates 371 corresponding to each other 2. A part around one opening 372 forms one electrostatic lens. In the electron beam limiting unit 34, the two openings 372 corresponding to each electrostatic lens partially overlap with any one of the apertures 352 of the aperture plate 351 farthest from the MCP 33 in the direction limiting unit 35 in the emission direction. The shift electrostatic lens array 37 is arranged in a state where the optical axis J3 parallel to the emission direction of the electrostatic lens passes through the center of the opening 352 of the aperture plate 351 and is shifted from the axis J2 parallel to the emission direction. . In FIG. 4, the amount of deviation between the axis J2 and the optical axis J3 in the horizontal direction in FIG. 4 is indicated by an arrow labeled W1 (the same applies to the amount of deviation W2 between the optical axis J3 and an axis J4 described later). ).

  Also in the intermediate aperture plate 38, a plurality of openings 381 are formed in the same arrangement as the plurality of microchannels 331, and each opening 381 is emitted from the opening 372 in one of the electrostatic lenses of the shift electrostatic lens array 37. The axis J4 passing through the center of the opening 381 and parallel to the emission direction is shifted from the optical axis J3 of the electrostatic lens so as to partially overlap in the direction (in FIG. 4, the light of the electrostatic lens An intermediate aperture plate 38 is disposed (in a state shifted from the position of the axis J3 to the opposite side of the axis J2 of the opening 352 of the aperture plate 351).

  At this time, as described above, since the optical axis J3 of the electrostatic lens and the axis J2 of the opening 352 of the aperture plate 351 are deviated, in the electron beam element subjected to the action of the electrostatic lens, each component The direction of travel differs depending on the travel speed of. Specifically, as shown by a long arrow B2 in FIG. 4, a component having a fast traveling speed has a small change in the traveling direction, and a component having a slow traveling speed as shown by a short arrow B2 in FIG. Changes in the traveling direction, and only a component having a substantially constant traveling speed passes through any opening 381 of the intermediate aperture plate 38. The component of the electron beam element that has passed through the intermediate aperture plate 38 is directed to the correction electrostatic lens array 39.

  The correction electrostatic lens array 39 has the same structure as the shift electrostatic lens array 37, and includes a pair of electrode plates 391 having a plurality of openings 392 formed in the same arrangement as the plurality of microchannels 331. The portion around the two openings 392 corresponding to each other of the pair of electrode plates 391 is one electrostatic lens. In the electron beam limiting unit 34, the correction electrostatic lens array 39 is arranged so that the front focal point of each electrostatic lens is at the center of one of the openings 381 of the intermediate aperture plate 38, and the electrostatic lens array 39 is static in parallel to the emission direction. The optical axis of the electro lens coincides with the axis J 4 of the opening 381 of the intermediate aperture plate 38. As a result, the traveling direction of the electron beam element that passes through the intermediate aperture plate 38 and enters the electrostatic lens of the correction electrostatic lens array 39 becomes approximately parallel to the emission direction.

  Actually, as described above, the plurality of velocity equalizing units 360, 360a are arranged in the emission direction, and the remaining velocity equalizing units 360 other than the first velocity equalizing unit 360a are also included in the shift electrostatic lens array 37. The structure is the same as that of the speed equalizing unit 360a of FIG. 4 which is a combination of the intermediate aperture plate 38 and the correction electrostatic lens array 39. In each of these speed uniformizing units 360 (that is, the second and subsequent speed uniformizing units 360), the two apertures 372 corresponding to each other in the shift electrostatic lens array 37 are arranged immediately before the speed uniformizing unit 360 in the emission direction. (That is, the electron beam element that partially overlaps one of the openings 392 of the correction electrostatic lens array 39 of the speed uniformizing unit 360 adjacent to the MCP 33 side (the lower side of FIG. 4) and passes through the opening 392. Is incident on a position off the optical axis of the electrostatic lens (center of the opening 372) of the shift electrostatic lens array 37, and the traveling direction of each component passing through the electrostatic lens differs depending on the traveling speed. It will be. Therefore, each speed uniformizing unit 360 also extracts a component having a constant traveling speed in the electron beam element.

  Even when the entire opening 392 of the correction electrostatic lens array 39 and the entire opening 372 of the shift electrostatic lens array 37 adjacent thereto are accurately overlapped in the emission direction, the electron beam element is In order to pass through the opening 381 of the intermediate aperture plate 38 while proceeding in a direction inclined with respect to the axis J4, the electron beam element that has passed through the opening 392 subsequently deviated from the center of the opening 372 of the shift electrostatic lens array 37. It becomes possible to limit the traveling speed of the electron beam element in the speed uniformizing unit 360 that is incident on the position and has the shift electrostatic lens array 37. Therefore, it is sufficient that the opening 392 of the correction electrostatic lens array 39 and the opening 372 of the shift electrostatic lens array 37 adjacent to the correction electrostatic lens array 39 overlap at least partially.

  FIG. 5 is a diagram showing the position of the electrostatic lens (opening 392) of the corrected electrostatic lens array 39 of the plurality of velocity equalizing units 360 and 360a when viewed along the emission direction. Further, in FIG. 5, the opening 352 of the aperture plate 351 farthest from the MCP 33 (that is, the last aperture plate 351) among the plurality of aperture plates 351 of the direction limiting portion 35 is also illustrated by a broken line. Actually, the opening 392 and the opening 352 have the same size.

  Here, as shown in FIG. 5, openings 392 (more precisely, two openings 392) constituting the electrostatic lenses of the plurality of correction electrostatic lens arrays 39 included in the plurality of velocity equalizing units 360, 360a. However, only one opening 392 is shown in FIG. 5) and the case where the opening 352 of the aperture plate 351 is projected on a plane perpendicular to the emission direction is considered. Further, attention is paid to each electrostatic lens of the correction electrostatic lens array 39 included in one of the speed uniformizing units 360 and 360a except the final speed uniformizing unit 360. Hereinafter, this electrostatic lens is referred to as a “target electrostatic lens”.

  In this case, the direction indicated by the emission vector starting from the center of the electrostatic lens of interest (that is, the center of the opening 392) and ending at the center of the electrostatic lens of the next speed equalization unit 360 is the electrostatic lens of interest. The center of the electrostatic lens of the speed uniformizing unit 360, 360a immediately before the (the opening 352 of the last aperture plate 351 when the target electrostatic lens is included in the first speed uniforming unit 360a) Only (360 / n) degrees (where n is an integer equal to or greater than 3 and n is 4 in the example of FIG. 5) with respect to the direction indicated by the incident vector having the center of the electrostatic lens as the end point. The speed equalizing units 360 and 360a are arranged so as to incline counterclockwise (may be clockwise). In the electron beam limiting unit 34, the speed uniformizing units 360 and 360a and the speed uniformizing units adjacent to the speed uniformizing units 360 and 360a (that is, the upper and lower speed uniformizing units) have the same positional relationship as described above. Thus, the path of each electron beam element by the plurality of velocity equalizing units 360, 360a is approximately spiral along the emission direction, and the traveling direction of the electron beam is suppressed from deviating from the central axis of the apparatus. Note that, depending on the design of the drawing apparatus 1, a plurality of directions such that the direction indicated by the incident vector in each target electrostatic lens is inclined by 180 degrees (that is, (360/2) degrees) with respect to the direction indicated by the emission vector. The speed uniformizing unit 360 may be arranged.

  In the drawing apparatus 1 according to the present embodiment, the electrostatic lens (opening 392) of the correction electrostatic lens array 39 included in the last speed uniformizing unit 360 is accurately in the exit direction with the opening 352 of the last aperture plate 351. The centers on the plane perpendicular to the emission direction of the plurality of electron beam elements that have overlapped and passed through the plurality of velocity uniformizing units 360, 360a are on the central axis J1.

  FIG. 6 is a perspective view showing the MCP 33. In the light emitting section 31 of the electron beam emitting section 3 in FIG. 1, the light beam cross section perpendicular to the central axis J1 becomes a ring shape (annular) centered on the central axis J1 by the single emission control by the control section 6. The electron beam elements are emitted in a ring shape from the microchannel 331 located at the same radius centered on the central axis J1 in the MCP 33 (hereinafter, the electron beam elements emitted in response to one emission control). The set is called “electron beam element group”.)

  Actually, as shown in FIG. 6, by changing the radius of the light pattern (symbols L1 to L5 in FIG. 6) sequentially emitted from the light emitting unit 31 for each emission control, the electron beam is changed. A plurality of electron beam element groups (in FIG. 6, an electron beam corresponding to the light pattern L1 of the ring radius r1) while changing the radius (hereinafter referred to as “ring radius”) on a plane perpendicular to the central axis J1 of the element group. The element group is indicated by the reference symbol E1). Here, it is assumed that all the emission sources corresponding to each electron beam element group are turned on, and the electron beam element group is emitted in a ring shape. Since the emission source ON / OFF is controlled by 6, the electron beam element group corresponding to one emission control is not necessarily an accurate ring shape. In FIG. 6, a voltage source 333 that applies a voltage between electrodes on both main surfaces of the MCP 33 perpendicular to the central axis J1 is also shown in a rectangular shape (the same applies to FIGS. 7 and 22 described later).

  FIG. 7 is a perspective view showing the MCP 33 and one electrostatic lens 41. In FIG. 7, the illustration of the electron beam limiting unit 34 (see FIG. 1) provided between the electrostatic lens 41 and the MCP 33 is omitted.

  As shown in FIG. 7, the electrostatic lens 41 of the electron optical system 4 is a combination of two ring members 411 centering on the central axis J1, and these ring members 411 formed of a conductive material such as metal. By applying a voltage between them by the voltage source 333, a potential that is rotationally symmetric with respect to the central axis J1 (that is, the electrostatic potential at each position on a plane perpendicular to the central axis J1 rotates around the central axis J1). An axisymmetric electric field that does not depend on the direction and depends only on the distance from the central axis J1 is generated. The electron beam element group that has passed through the electron beam limiting unit 34 is accelerated by an accelerating tube unit 49 (not shown in FIG. 1) and enters the electrostatic lens 41 along a path parallel to the central axis J1. To do. At this time, in the drawing apparatus 1, the electric field acting on the electron beam element group by the electrostatic lens 41 is changed according to the ring radius.

  8 and 9 are diagrams showing the trajectory of the electron beam element group, and FIG. 9 is an enlarged view of a portion surrounded by a circle labeled A1 in FIG. 8 and 9, the vertical axis indicates the position in one direction perpendicular to the central axis J1 (the radial direction of the ring-shaped electron beam element group, indicated as the r direction in FIGS. 8 and 9). The horizontal axis indicates the position in the direction of the central axis J1 (shown as the z direction in FIGS. 8 and 9), and the z axis coincides with the central axis J1 (FIGS. 11, 12, and 12 described later). 19 and FIG. 20).

  In the drawing apparatus 1, when the electron beam emitting unit 3 sequentially emits the electron beam element groups indicating the trajectories with lines E1 to E9 in FIG. 8, different voltages V <b> 1 are controlled by the control of the control unit 6. By applying ~ V9 to the electrostatic lens 41 and changing the electric field acting on the electron beam element groups E1 to E9 according to the ring radii of the electron beam element groups E1 to E9, as shown in FIG. All the electron beam element groups E1 to E9 (in FIG. 9, only the trajectories of some of the electron beam element groups are labeled) are on the central axis J1 (on the z axis) regardless of the ring radius. It passes through almost the same position. The electron beam element groups E1 to E9 that have passed through the electrostatic lens 41 enter another electrostatic lens 42 shown in FIG.

  The electrostatic lens 42 has the same configuration as that of the electrostatic lens 41 of FIG. 7, and a rotationally symmetric potential is generated with respect to the central axis J1. Further, the front focal point of the electrostatic lens 42 on the stage 21 side is arranged at the rear focal point of the electrostatic lens 41 on the MCP 33 side, and the two electrostatic lenses 41 and 42 arranged along the central axis J1 are both-side telecentric optics. The system is configured. In the electrostatic lens 42 as well, similar to the electrostatic lens 41, the electric field acting on the electron beam element groups E1 to E9 is changed according to the ring radius by applying different voltages to the electron beam element groups E1 to E9. Is done. As a result, the path of the electron beam element group that sequentially passes through the same position on the central axis J1 by the action of the electrostatic lens 41 is accurately made parallel to the central axis J1 by the electrostatic lens 42, and the electron beam element group Is guided onto the substrate 9. In practice, the image on the exit surface of the MCP 33 is reduced and formed on the substrate 9, and a fine pattern is formed on the substrate 9 by irradiation with a plurality of electron beam element groups modulated according to the drawing data 612. In the electron optical system 4, other optical elements may be provided as necessary.

  Next, a method for determining the voltage to be applied to the electrostatic lenses 41 and 42 when the electron beam element groups are emitted will be described. FIG. 10 is a diagram showing a flow of processing for determining a voltage to be applied to the electrostatic lens. Hereinafter, description will be made by paying attention to the electrostatic lens 41 provided on the MCP 33 side. In the following description, two axes perpendicular to the z axis are defined as an x axis and a y axis.

In the applied voltage calculation unit 64, first, the speed at which electrons, which are components of the electron beam element, enter the electrostatic lens 41 is obtained using the set values of the control parameters in the electron beam emitting unit 3, and the electrostatic lens 41. The initial value of the applied voltage is set (step S11). Here, focusing on one electron beam element group having a ring radius rj (where j is a positive integer), the applied voltage is expressed as V _{j, i} . As will be described later, the applied voltage is updated as necessary, and the subscript i indicates the number of updates.

Subsequently, a three-dimensional potential distribution P _{j, i} (x, y, z) when the applied voltage V _{j, i} is applied to the electrostatic lens 41 is obtained by calculation (step S12). Thus, the trajectory of the electron beam element group is calculated (step S13). In Equation 1, m represents the mass of electrons, r _v denotes the position vector of the electron, n indicates the electron conductive frustrated. Further, r _v ⁽²⁾ indicates a second derivative (that is, an acceleration vector) with respect to the time of r _v .

When the trajectory of the electron beam element group is calculated, a position z _{j, i at} which the trajectory intersects with the z axis (center axis J1) is obtained, and a difference Δz from a predetermined target position zA is calculated (step). S14). The difference Δz is compared with a predetermined threshold value β. If the difference Δz is larger than the threshold value β (that is, (Δz> β)) (step S15), i is incremented by 1 and the applied voltage V _{j, i} Is updated (step S16). For example, the updated applied voltage V _{j, i} is expressed by Equation 2 using the difference Δz, where the immediately preceding applied voltage is V _{j, i−1} . Α is a predetermined coefficient.

When the applied voltage V _{j, i} is updated, the three-dimensional potential distribution P _{j, i} (x, y, z) is obtained (step S12) and the trajectory of the electron beam element group is calculated as described above. (Step S13), a difference Δz between a position z _{j, i} where the trajectory intersects the z-axis (center axis J1) and the target position zA is calculated (step S14). In the applied voltage calculation unit 64, the processes of steps S12 to S14 are repeated (step S15) while updating the applied voltage V _{j, i} until the difference Δz becomes equal to or less than the threshold value β (step S16).

By the above iterative process, an applied voltage that reduces the difference between the position z _{j, i} where the trajectory of the electron beam element group intersects the z axis and the target position zA is obtained, as shown by the arrow labeled B3 in FIG. It becomes possible. In FIG. 11, the positions where the trajectory of the electron beam element group intersects the z-axis when the number of updates is 1, 2, and 3 (that is, i is 1, 2, and 3) are shown as z1, z2, and z3, respectively. ing. When the difference Δz becomes equal to or less than the threshold value β (that is, (Δz ≦ β)) (step S15), the current applied voltage is determined as the optimum applied voltage V _{j, ie} (step S17).

Actually, the processing of steps S11 to S17 is performed on the electron beam element groups having the respective ring radii to obtain the optimum applied voltage, and when each electron beam element group enters the electrostatic lens 41, An optimum applied voltage is applied to the electrostatic lens 41. As a result, as shown in FIG. 12, P _{1, ie} (x, y, z) and P _{2, ie} (x, y) are emitted when the electron beam element groups having the respective ring radii r1, r2, r3, r4, r5 are emitted. y, z), P _{3, ie} (x, y, z), P _{4, ie} (x, y, z), and P _{5, ie} (x, y, z) are generated, and each electron beam element is generated. The group passes near the target position zA. Similarly, in the electrostatic lens 42, the optimum applied voltage is determined so that the path of the electron beam element group that has passed through approximately the same position on the central axis J1 is parallel to the central axis J1.

  Next, calibration processing in the drawing apparatus 1 will be described. In the present embodiment, as shown in FIG. 13, a reference substrate on which a pattern spreading radially from a predetermined position is prepared in advance. In the pattern on the reference substrate in FIG. 13, the portion with parallel diagonal lines protrudes by, for example, 10 nm from the white portion, and as shown in the upper part of FIG. 14, the circumferential direction (arbitrary radial position) In FIG. 14, the convex portion 911 and the concave portion 912 having the same width are repeated.

  In the drawing apparatus 1 of FIG. 1, the reference substrate is placed on the stage 21, and the stage 21 is arranged so that the center of the radial pattern is located on the central axis J1. Subsequently, secondary electrons emitted from the reference substrate are detected by the detector 5 while the reference substrate is irradiated with the electron beam from the electron beam emitting unit 3 via the electron optical system 4.

  Here, a basic operation in detecting secondary electrons emitted from the reference substrate while irradiating the reference substrate with the electron beam will be described. In the following description, it is assumed that the electron beam emitting unit 3 has M emission sources (microchannels 331).

  In the basic operation, in one of the M emission sources, only one emission source is turned on, the remaining emission sources are turned off, and the reference substrate is emitted from the reference substrate by irradiation of the electron beam elements from the turned-on emission sources. The secondary electrons thus detected are detected by the detector 5. At this time, the voltage applied between the ring members of the electrostatic lenses 41 and 42 is changed to the optimum applied voltage corresponding to the ring radius of the electron beam element group including the electron beam elements from the emission source to be turned on. The In the drawing apparatus 1, the above operation is repeated while switching the emission source to be turned on, whereby the output value of the detector 5 when each of the M emission sources is turned on is acquired. Since the electron beam elements from the M emission sources are irradiated to M positions in the same arrangement as the M emission sources on the reference substrate, respectively, the output value of the detector 5 at each of these positions. Is associated with each other, an image of the reference substrate (hereinafter referred to as an “electron microscope image”) is acquired.

  As described above, since the actual electron beam emitting unit 3 is provided with a large number of emission sources, in order to obtain an electron microscope image in a short time, the ON time of each emission source is shortened and turned on. It is necessary to quickly switch the emission source. However, if the ON time of the emission source is shortened, the amount of secondary electrons emitted from the reference substrate is reduced, so that the influence of noise increases, the detection sensitivity in the detector 5 decreases, and the electron microscope image is displayed. It may be difficult to obtain with high accuracy.

  Therefore, in a preferable operation when detecting the secondary electrons emitted from the reference substrate while irradiating the reference beam on the reference substrate, a method similar to that of JP 2007-141797 A described above (Patent Document 3) is used. In a plurality of emission sources corresponding to each electron beam element group emitted in a ring shape at the time of pattern drawing, the detector 5 performs secondary operation while turning on two or more emission sources by one emission control. Electrons are detected and the combination of the emission sources to be turned on is changed based on a predetermined rule, and emission control of the electron beam elements is performed a plurality of times. For example, as shown in FIG. 15, when one electron beam element group emitted in a ring shape includes n electron beam elements a1, a2,..., Ak,. Under the control of the encoded signal generator 613, the detector 5 performs secondary detection while turning on two or more specific emission sources among n emission sources that emit the electron beam elements included in the electron beam element group. The operation of detecting electrons is repeated n times by changing the emission source to be turned on in n ways.

  Here, in one emission control, the emission source to be turned on is set to 1, and the emission source to be turned off is set to 0. As shown in FIG. 16, n pieces corresponding to electron beam elements from a1 to an are obtained. The ON / OFF states of the emission sources are represented by an n-dimensional row vector in numerical order, and those corresponding to n emission controls are arranged in the column direction (vertical direction in FIG. 16), so that n rows n A column electron beam irradiation matrix B is set. Further, the amount of secondary electrons emitted from the reference substrate due to only the electron beam element from each emission source (a part of the amount of electrons detected by the detector 5 and the emission source is turned on) In this case, the n-dimensional column vector in which the output values in the detector 5 are arranged in the column direction in time series is defined as A. Is S, and an n-dimensional column vector in which noise (equipment noise) superimposed on the output value in the detector 5 is arranged in the column direction in time series is C, an electron beam irradiation matrix B, column vector A, column vector The relationship between S and the column vector C is expressed as (BA + C = S).

  In this operation example, the column vector S is acquired as an output value in the detector 5, and the column vector C is also acquired in a state in which the electron beam is not irradiated on the reference substrate, so that an inverse matrix of the electron beam irradiation matrix B exists. In other words, when the electron beam irradiation matrix B is a regular matrix, a column vector A indicating the amount of secondary electrons emitted from the reference substrate due to only the electron beam element from each emission source can be calculated. It becomes. At this time, in order to increase the total amount of electrons emitted from the reference substrate by one emission control and reduce the influence of noise, the ratio of the value 1 in all rows of the electron beam irradiation matrix B is increased. The Hadamard matrix is an example of one that satisfies such a condition. As a result, the amount of secondary electrons emitted from the reference substrate due to only the electron beam element from each emission source is set to a high S / N ratio (approximately (n / 2) times the square root of the basic operation). Increase). Then, by performing the above operation on the electron beam element groups having all the ring radii (r = r1, r2,..., Rj,...), The ON time in the emission source is shortened and the reference substrate It becomes possible to acquire an electron microscope image with high accuracy. In the basic operation, it can be understood that the electron beam irradiation matrix B is a unit matrix.

  As described above, the reference substrate has a pattern that spreads radially from a predetermined position. As shown in the upper part of FIG. 14, the diameter (spot diameter) D1 of the irradiation region of each electron beam element on the reference substrate. , D2 spreads, the corresponding part in the electron microscope image is blurred as shown in the lower part of FIG. Therefore, in the drawing apparatus 1, the control parameters of the electron beam emitting unit 3 and the like are changed until the repetition of the convex portion 911 and the concave portion 912 corresponding to each ring radius rj is accurately expressed in the electron microscope image of the reference substrate. The operation of acquiring the electron microscope image is repeated. Thereby, the final value of the control parameter of the electron beam emitting unit 3 and the like is determined for each ring radius of the electron beam element group, and the calibration process is completed. In addition, when the electron beam irradiation matrix is used, it is possible to perform the calibration process in a short time.

  Incidentally, as shown in FIG. 17, when only one electron beam element (indicated by a line denoted by reference numeral 94 in FIG. 17 and the same in FIG. 18) is used, the spherical aberration of the electrostatic lens 93 is reduced. There is no need to consider the impact. However, as shown in FIG. 18, when a plurality of electron beam elements 94 pass through the electrostatic lens 93 simultaneously, it is necessary to consider the influence of spherical aberration. That is, in the electrostatic lens 93 on which a plurality of electron beam elements parallel to the optical axis (center axis) are incident, a large electrostatic force is applied toward the optical axis due to a steep potential gradient at a position away from the optical axis. 19 and FIG. 19 is an enlarged view of a portion surrounded by a circle denoted by reference numeral A2 in FIG. 19, and is separated from the optical axis (z axis) when entering the electrostatic lens 93, as shown in FIG. The position where the electron beam element passes through the optical axis by the action of the electrostatic lens 93 is close to the optical axis when the electron beam element enters the electrostatic lens 93. Phenomenon that is closer to the electrostatic lens 93 than the position passing through (behind the traveling direction), that is, spherical aberration occurs. As a result, the positional accuracy of the electron beam element irradiated onto the substrate is lowered, and the pattern to be drawn is drawn distorted as the distance from the optical axis (center) increases.

  On the other hand, in the electron beam irradiation apparatus realized by the electron beam emitting unit 3, the electron optical system 4, and the control unit 6 in FIG. 1, the electron beam element group emitted in a ring shape around the central axis J1 has a ring radius. By the electrostatic lens 41 of the electron optical system 4 so that the electron beam element group passes through the same position on the central axis J1 regardless of the ring radius. The field acting on the electron beam element group is changed according to the ring radius. Thereby, it is possible to prevent the spherical aberration from occurring in the electrostatic lens 41, and to accurately irradiate the electron beam element that can be modulated (that is, the intensity control and the timing control) on the substrate 9.

  In the drawing apparatus 1 having the electron beam irradiation apparatus, when the pattern is drawn, the electron beam irradiation apparatus controls the irradiation of the electron beam onto the substrate 9 according to the drawing data 612, thereby drawing the pattern with high accuracy. Can do. This is also the case where the distance between the electron optical system 4 and the substrate 9 is changed by preventing the spherical aberration from occurring in both of the two electrostatic lenses 41 and 42 constituting the double telecentric optical system. However, the magnification is constant even when the size of the irradiation region of the electron beam element group on the substrate 9 (ring radius on the substrate 9) is prevented from changing (that is, even if the coordinate of the irradiation region in the optical axis direction is changed). The electron beam element can be irradiated with high accuracy.

  Further, in the drawing apparatus 1 of FIG. 1, the electron beam irradiation apparatus and the detector 5 realize the function as an electron microscope, and the substrate 9 on which a predetermined pattern is formed (the electron beam resist 92 is not formed). The above basic operation for acquiring an electron microscope image while changing the voltage between the ring members of the electrostatic lenses 41 and 42 according to the ring radius, or By performing the operation using the electron beam irradiation matrix of FIG. 16, it is possible to accurately irradiate the electron beam elements onto the substrate 9 and to acquire the image of the substrate 9 with high accuracy. In addition, an electron microscope that acquires an electron microscope image by an operation using an electron beam irradiation matrix can acquire an image of the substrate 9 at high speed.

  By the way, when all the electron beam elements pass through the vicinity of the optical axis of the electrostatic lens, it is not necessary to consider the influence of spherical aberration caused by the electrostatic lens. Therefore, as shown in FIG. When 94 is emitted, the region on the surface perpendicular to the optical axis of the bundle of a plurality of electron beam elements 94 incident on the electrostatic lens is a circle having a diameter of several tens of centimeters. In this case, when an electrostatic lens composed of a ring member having a diameter of several m to 10 m is provided, these electron beam elements 94 pass through the vicinity of the optical axis (center axis) of the electrostatic lens 93a. And the influence of spherical aberration can be ignored. However, it is not realistic to use the electrostatic lens 93a having such a size in the drawing apparatus from the viewpoint of installation space, manufacturing cost, difficulty in adjustment, and the like.

  Therefore, a method for generating a potential equivalent to the potential generated by the huge electrostatic lens 93a with a small lens device will be described. FIG. 22 is a perspective view showing a lens device 4a used in the drawing apparatus 1 according to another example. The lens device 4a is used in place of the electrostatic lens 41 (and the electrostatic lens 42) of FIG. In FIG. 22, the MCP 33 of the electron beam emitting unit 3 is also illustrated.

  Here, first, a three-dimensional distribution of the potential generated by the giant electrostatic lens 93a indicated by a two-dot chain line in FIG. 22 is obtained by calculation, and a space through which all electron beam elements from the MCP 33 pass (that is, The potential in the cylindrical space whose distance from the central axis J1 is a predetermined value is specified. In the lens device 4a, as shown in FIG. 22, a plurality of ring members 431 (preferably four or more ring members 431, each having a center axis J1 as a center and thin in the direction of the center axis J1 are more preferable. 10 or more ring members 431) are arranged along the central axis J1, and the voltage source 333 generates a predetermined number of ring members 431 so that the potential specified by the above calculation is generated. Is applied, a potential equivalent to the case where the giant electrostatic lens 93a is provided (that is, a potential in the vicinity of the optical axis of the giant electrostatic lens 93a (also called a paraxial potential)) is generated. Is done.

  Accordingly, the central axis J1 is emitted simultaneously from the plurality of microchannels 331 (see FIG. 2) which are a plurality of emission sources two-dimensionally arranged on a plane perpendicular to the central axis J1 and into the plurality of ring members 431. The plurality of electron beam elements incident in parallel with each other pass through substantially the same position on the central axis J1 regardless of the distance from the central axis J1.

  As described above, in the lens device 4a, the electrostatic lens 93a (for example, the diameter of the ring member 431 is sufficiently larger than the plurality of ring members 431 in the spaces in the plurality of ring members 431 through which the plurality of electron beam elements pass. By applying a potential to the plurality of ring members 431 so that a potential equivalent to the potential generated by an electrostatic lens having a diameter of 5 to 100 times the diameter of It is possible to prevent the spherical aberration from occurring in the configured lens and to irradiate the electron beam element onto the substrate 9 with high accuracy.

  Of course, the lens apparatus 4a of FIG. 22 may be used for an electron microscope. As described above, in the lens device 4a, since spherical aberration is suppressed even in a region away from the optical axis to some extent, in such an electron microscope, it is possible to obtain an electron microscope image with high accuracy while achieving miniaturization. it can. In this case, when the method using the electron beam irradiation matrix of FIG. 16 is adopted, one electron beam irradiation matrix for all the emission sources is set, and an electron microscope image is acquired at high speed with a high S / N ratio. Is done.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made.

  1, the photoelectric film 332 is provided on the MCP 33. Depending on the energy and wavelength of light emitted from the light emitting unit 31, electrons are emitted in the microchannel 331 by incident light. Therefore, the photoelectric film 332 can be omitted. Further, instead of the combination of the photoelectric film 332 and the MCP 33, a high-gain avalanche rushing amorphous photoconductor (HARP) film may be used. Furthermore, instead of the combination of the light emitting unit 31 and the converting unit 32, for example, an electron beam emitting unit 7 shown in FIG. 23 may be used. In the electron beam emitting portion 7 of FIG. 23, electrons emitted from the emitter 71 are emitted through an opening 721 formed in the extraction electrode 72.

  Depending on the design of the drawing apparatus 1, only one aperture plate 351 may be provided in the direction limiting unit 35 in FIG. 3. In the electron beam limiting unit 34, a plurality of apertures 352 having a plurality of apertures 352 formed in the same arrangement as the plurality of microchannels 331 are arranged in the emission direction, thereby providing a plurality of emission from the MCP 33. It is possible to limit the traveling direction of the electron beam element to a certain direction.

  Further, in the electron beam limiting unit 34 in the above embodiment, three or more speed uniformizing units 360 and 360a are provided, but even when only one speed uniformizing unit 360a is provided, the electron beam limiting unit 34 is in a certain direction. It is possible to emit an electron beam element that travels at a constant speed. However, in order to make the speed of the electron beam element more constant in the electron beam limiting unit 34, it is preferable to provide at least one speed uniformizing unit 360 in addition to the initial speed uniformizing unit 360a.

  In the electron optical system 4, the lens that generates the rotationally symmetric potential may be an electromagnetic lens (magnetic field lens) in addition to the electrostatic lens. In this case as well, a ring-shaped electron beam element group is sequentially emitted, and a magnetic field acting on the electron beam element group by the electromagnetic lens is ringed so that the electron beam element group passes through the same position on the central axis J1. By changing according to the radius, it is possible to prevent spherical aberration from occurring in the electromagnetic lens, and to irradiate the electron beam element onto the substrate with high accuracy.

  The drawing apparatus 1 of FIG. 1 can perform drawing in a lump area directly from the drawing data 612 without using a reticle or the like (that is, without a mask). Although various types of semiconductor devices can be manufactured in a short time and at low cost, an electron beam irradiation apparatus in the drawing apparatus 1 is disclosed in, for example, US Pat. No. 5,466,904 ( It may be used in a drawing apparatus using a reticle in Patent Document 1). However, with this apparatus, it is necessary to scan the irradiation region of the electron beam on the reticle, or it is impossible to manufacture a reticle having a portion where the periphery is a hole (ie, an isolated island-like portion). Because of this problem, the electron beam irradiation apparatus is particularly suitable for the drawing apparatus 1 of FIG.

  The object irradiated with the electron beam may be other than the substrate on which the resist is formed. In addition, the electron beam irradiation apparatus, the electron beam emission apparatus that is the electron beam emission unit 3, and the lens apparatus 4a are apparatuses that emit charged particle beams other than the electron beam (for example, a focused ion beam that emits an ion beam). It is also possible to use it in an apparatus etc. As described above, the electron beam irradiation apparatus is a form of a charged particle beam irradiation apparatus that irradiates a target with a charged particle beam, and the electron beam emission apparatus is a type of a charged particle beam emission apparatus that emits a charged particle beam. It can be said that the lens device 4a is a form of a lens device for charged particle beams. Similarly, a charged particle beam other than an electron beam may be used in the drawing apparatus 1 and the electron microscope. The drawing apparatus 1 is one of apparatuses that draw a pattern by irradiating a charged particle beam on an object. The electron microscope can be said to be one of analysis microscopes that acquire an image of an object by irradiating the object with a charged particle beam.

  Further, the detector 5 in the analytical microscope is not limited to one that detects secondary electrons from the object, but may be any one that detects particle beams or electromagnetic waves emitted from the object by irradiation with charged particle beams, Thereby, the image of the object can be obtained with high accuracy.

DESCRIPTION OF SYMBOLS 1 Drawing apparatus 3 Electron beam emission part 4 Electron optical system 4a Lens apparatus 5 Detector 6 Control part 7 Electron beam emission part 9 Substrate 31 Light emission part 32 Conversion part 35 Direction restriction part 36 Speed equalization part 37 Shift electrostatic lens array 38 Intermediate aperture plate 39 Correction electrostatic lens array 41, 42 Electrostatic lens 331 Micro channel 333 Voltage source 351 Aperture plate 352, 372, 381, 392 Opening 360, 360a Speed uniformizing unit 371, 391 Electrode plate 431 Ring member 611 Memory 612 Drawing data E1 to E9 Electron beam element group J1 Central axis L1 to L5 Light pattern r1 to r5, rj Ring radius

Claims (10)

A charged particle beam irradiation apparatus that irradiates a target with a charged particle beam,
A charged particle beam emitting section for emitting a plurality of charged particle beam elements capable of intensity control and timing control from a plurality of emission sources arranged two-dimensionally on a plane perpendicular to the emission direction;
A charged particle optical system having a lens that generates a rotationally symmetric potential with respect to a central axis parallel to the emission direction, and guiding the plurality of charged particle beam elements onto an object;
The charged particle beam element group emitted in a ring shape around the central axis is sequentially emitted from the charged particle beam emission unit while changing the ring radius, and the charged particle beam element group is emitted regardless of the ring radius. A control unit that changes a field acting on the charged particle beam element group by the lens according to the ring radius so as to pass through the same position on the central axis;
A charged particle beam irradiation apparatus comprising: The charged particle beam irradiation apparatus according to claim 1,
The path of the charged particle beam element group incident on the lens is parallel to the central axis,
The charged particle optical system generates a rotationally symmetric potential with respect to the central axis, and a path of the charged particle beam element group that has passed through the same position on the central axis is parallel to the central axis. As described above, the charged particle beam irradiation apparatus further includes another lens that changes a field acting on the charged particle beam element group according to the ring radius. The charged particle beam irradiation apparatus according to claim 1 or 2,
The charged particle beam emitting portion is
A charged particle beam generation unit that emits the plurality of charged particle beam elements while generating the plurality of charged particle beam elements at the plurality of emission sources arranged two-dimensionally on a plane perpendicular to the emission direction;
The plurality of charged particle beams emitted from the charged particle beam generation unit having a plurality of apertures arranged in the emission direction and having at least one aperture plate formed in the same arrangement as the plurality of emission sources. A direction limiter that limits the travel direction of the element to a certain direction;
A speed uniformizing unit that uniformizes the traveling speed of the plurality of charged particle beam elements that have passed through the direction limiting unit;
With
The speed uniformizing unit is
A pair of electrode plates having a plurality of openings formed in the same arrangement as the plurality of emission sources, and a portion around the two openings corresponding to each other of the pair of electrode plates has one electrostatic A shift electrostatic lens that is a lens and in which the two openings partially overlap with any one of the aperture plates of the at least one aperture plate that is farthest from the charged particle beam generator in the emission direction. An array,
A plurality of apertures are formed in the same arrangement as the plurality of emission sources, and a part of the charged particle beam element subjected to the action of each electrostatic lens of the shift electrostatic lens array An intermediate aperture plate that passes through either
A pair of electrode plates having a plurality of openings formed in the same arrangement as the plurality of emission sources, and a portion around the two openings corresponding to each other of the pair of electrode plates has one electrostatic A correction electrostatic lens array in which the front focal point of each electrostatic lens is the center of one of the openings of the intermediate aperture plate,
A charged particle beam irradiation apparatus comprising: The charged particle beam irradiation apparatus according to claim 3,
The speed uniformizing unit emits at least one speed uniformizing unit having the same structure as the first speed uniformizing unit that is a combination of the shift electrostatic lens array, the intermediate aperture plate, and the correction electrostatic lens array. Arranged in a direction,
Two corresponding apertures of each shift electrostatic lens array of each of the at least one velocity uniformizing unit are at least partly one of the apertures of the correction electrostatic lens array of the previous velocity uniformizing unit in the emission direction. Charged particle beam irradiation apparatus characterized by overlapping with each other. The charged particle beam irradiation apparatus according to claim 4,
The at least one speed leveling unit is two or more speed leveling units;
The charged particle beam irradiation apparatus, wherein a path of each charged particle beam element by the first velocity uniformizing unit and the two or more velocity uniformizing units is approximately spiral along the emission direction. The charged particle beam irradiation apparatus according to any one of claims 3 to 5,
The charged particle beam generator is
A light emitting section for emitting spatially modulated light;
Each of the plurality of charged particle beam elements has a plurality of microchannels each extending in the emission direction and amplifying electrons therein as the plurality of emission sources, and is caused by incidence of light from the light emission unit. A conversion unit that emits light,
A charged particle beam irradiation apparatus comprising: A drawing apparatus for drawing a pattern by irradiating a target with a charged particle beam,
The charged particle beam irradiation apparatus according to any one of claims 1 to 6,
A storage unit for storing drawing data;
With
A drawing apparatus, wherein the charged particle beam irradiation apparatus controls irradiation of a charged particle beam onto an object according to the drawing data. An analysis microscope that acquires an image of an object by irradiating the object with a charged particle beam,
The charged particle beam irradiation apparatus according to any one of claims 1 to 6,
A detector for detecting a particle beam or electromagnetic wave emitted from an object by irradiation of a charged particle beam;
An analysis microscope comprising: A charged particle beam emitting device for emitting a charged particle beam,
A charged particle beam generator that emits a plurality of charged particle beam elements while generating a plurality of charged particle beam elements at a plurality of emission sources arranged two-dimensionally on a plane perpendicular to the emission direction;
The plurality of charged particle beams emitted from the charged particle beam generation unit having a plurality of apertures arranged in the emission direction and having at least one aperture plate formed in the same arrangement as the plurality of emission sources. A direction limiter that limits the travel direction of the element to a certain direction;
A speed uniformizing unit that uniformizes the traveling speed of the plurality of charged particle beam elements that have passed through the direction limiting unit;
With
The speed uniformizing unit is
A pair of electrode plates having a plurality of openings formed in the same arrangement as the plurality of emission sources, and a portion around the two openings corresponding to each other of the pair of electrode plates has one electrostatic A shift electrostatic lens that is a lens and in which the two openings partially overlap with any one of the aperture plates of the at least one aperture plate that is farthest from the charged particle beam generator in the emission direction. An array,
A plurality of apertures are formed in the same arrangement as the plurality of emission sources, and a part of the charged particle beam element subjected to the action of each electrostatic lens of the shift electrostatic lens array An intermediate aperture plate that passes through either
A pair of electrode plates having a plurality of openings formed in the same arrangement as the plurality of emission sources, and a portion around the two openings corresponding to each other of the pair of electrode plates has one electrostatic A correction electrostatic lens array in which the front focal point of each electrostatic lens is the center of one of the openings of the intermediate aperture plate,
A charged particle beam emitting apparatus comprising: A lens device for charged particle beams,
A plurality of ring members each centered on the central axis and arranged along the central axis;
Spaces in the plurality of ring members through which a plurality of charged particle beam elements that are emitted from a plurality of emission sources two-dimensionally arranged on a plane perpendicular to the central axis and enter the plurality of ring members pass. A voltage source for applying a potential to the plurality of ring members so that a potential equivalent to a potential generated by a lens sufficiently larger than the plurality of ring members is generated;
A lens apparatus for charged particle beams, comprising:

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