JP2006012524A - Electron lens member and electron beam application apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electron beam exposure apparatus that suppresses an increase in size of a power unit for controlling a lens field and allows easy arrangement of components. <P>SOLUTION: An electron lens has a coil 1 formed in a center portion thereof and embedded in a ferromagnetic material 2. The periphery of the ferromagnetic material 2 is divided into two portions that form flange portions 2a, 2b. The flange portions 2a, 2b respectively have a plurality of lens apertures 3a, 3b, and the positions of the lens apertures 3a, 3b as seen in a plan view coincide with each other. Due to a magnetic force produced by the coil 1, the flange portion 2a forms the north pole while the flange portion 2b forms the south pole, for example, and because of this structure, the north and south poles face each other. Since the coil 1 is formed inside and the lens apertures 3a, 3b are formed outside the coil 1, the coil 1 is compact and is therefore low in impedance. This structure enables driving at low power, and it is thus easy to control the lens field. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is an electron used in an electron beam application apparatus to which an electron beam is applied, such as a multi-beam electron beam exposure apparatus mainly used for manufacturing semiconductor integrated circuits and the like, and a multi-beam electron beam inspection apparatus used for wafer inspection or the like. The present invention relates to a lens member and an electron beam application apparatus using the electron lens member.

  In recent years, semiconductor devices have been miniaturized rapidly, and an exposure apparatus that exposes a pattern for forming wirings included in the semiconductor device is required to have extremely high exposure accuracy. As an exposure apparatus that exposes such a pattern, development of a multi-beam electron beam exposure apparatus that performs exposure processing using a plurality of electron beams has been underway. On the other hand, development of an inspection apparatus using a multi-beam electron beam is in progress in order to inspect a wafer in a semiconductor device manufacturing process.

  Since an example of such a multi-beam electron beam exposure apparatus is described in Patent Republished WO 01/075951 (Patent Document 1), as an example of the technology that is the premise of the present invention, Patent Document 1 The following description is made with reference to the drawings and the description thereof.

  FIG. 2 is a diagram showing a configuration of the electron beam exposure apparatus 100 described in Patent Document 1. As shown in FIG. The electron beam exposure apparatus 100 includes an exposure unit 150 for performing a predetermined exposure process on the wafer 44 by an electron beam, and a control system 140 for controlling the operation of each component included in the exposure unit 150.

  The exposure unit 150 includes a housing 8 provided with a plurality of exhaust holes 70, electron beam forming means for generating a plurality of electron beams and forming a cross-sectional shape of the electron beam as desired, and a plurality of electron beams on the wafer 44. And an electron optical system including an irradiation switching unit that switches independently for each electron beam and a wafer projection system that adjusts the orientation and size of the pattern image transferred to the wafer 44. The exposure unit 150 includes a stage system including a wafer stage 46 on which a wafer 44 whose pattern is to be exposed is placed, and a wafer stage drive unit 48 that drives the wafer stage 46.

  The electron beam shaping means includes an electron beam generator 10 that generates a plurality of electron beams, an anode 13 that emits the generated electron beams, and a plurality of openings that shape the cross-sectional shape of the electron beams by passing the electron beams. A slit cover 11, a first molding member 14, and a second molding member 22, a first multi-axis electron lens 16 that independently focuses a plurality of electron beams and adjusts the focus of the electron beam, and a first multi-axis. A first lens intensity adjusting unit 17 that adjusts a lens intensity, which is a force that a magnetic field formed in each lens opening of the lens 16 gives to an electron beam that passes through the lens opening, and an electron that has passed through the anode 13. A slit deflector 15 for independently deflecting the beam, a first shaping deflector 18 for independently deflecting a plurality of electron beams that have passed through the first shaping member 14, and And a second shaping deflecting section 20.

  The electron beam generator 10 includes an insulator 106, a cathode 12 that generates thermoelectrons, and a grid 102 that is formed so as to surround the cathode 12 and stabilizes thermoelectrons generated at the cathode 12. In FIG. 2, the electron beam generator 10 has a plurality of electron guns (comprised of a cathode 12 and a grid 102) provided at a predetermined interval on an insulator 106, thereby forming an electron gun array.

  The irradiation switching means independently converges a plurality of electron beams and independently adjusts the lens intensity at each lens opening of the second multi-axis electron lens 24 for adjusting the focus of the electron beam. A lens intensity adjusting unit 25 for adjusting and a blanking electrode array for independently switching for each electron beam whether or not to irradiate the wafer 44 with the electron beam by deflecting a plurality of electron beams independently for each electron beam. 26 and an electron beam shielding member 28 that includes a plurality of openings through which the electron beam passes and shields the electron beam deflected by the blanking electrode array 26.

  The projection system for a wafer focuses a plurality of electron beams independently, and adjusts the rotation of an electron beam image irradiated on the wafer 44, and each lens opening of the third multi-axis electron lens 34. A third lens intensity adjusting unit 35 that independently adjusts the lens intensity in the unit, and a fourth multi-axis electron lens 36 that focuses a plurality of electron beams independently and adjusts a reduction rate of the electron beam irradiated on the wafer 44. A fourth lens intensity adjustment unit 37 that independently adjusts the lens intensity at each lens opening of the fourth multi-axis electron lens 36, and a plurality of electron beams at a desired position on the wafer 44, independently for each electron beam. And a fifth multi-axis electron lens 62 that independently converges a plurality of electron beams and functions as an objective lens for the wafer 44.

  The control system 140 includes an overall control unit 130, a multi-axis electron lens control unit 82, a reflected electron processing unit 99, a wafer stage control unit 96, and an individual control unit that independently controls exposure parameters for a plurality of electron beams. 120. The overall control unit 130 is a workstation, for example, and performs overall control of each control unit included in the individual control unit 120. The multi-axis electron lens control unit 82 controls the current supplied to the first multi-axis electron lens 16, the second multi-axis electron lens 24, the third multi-axis electron lens 34, and the fourth multi-axis electron lens 36. The backscattered electron processing unit 99 receives a signal based on the amount of backscattered electrons or secondary electrons detected by the backscattered electron detection device 50 and notifies the overall control unit 130 of the received signal. The wafer stage control unit 96 controls the wafer stage driving unit 48 to move the wafer stage 46 to a predetermined position.

  The individual control unit 120 includes an electron beam control unit 80 that controls the electron beam generation unit 10, a shaping deflection control unit 84 that controls the first shaping deflection unit 18 and the second shaping deflection unit 20, and each lens intensity adjustment unit ( 17, 25, 35, 37), a lens intensity control unit 88 that controls the voltage applied to the deflection electrodes included in the blanking electrode array 26, and a plurality of deflection units 60. And a deflection control unit 98 for controlling the voltage applied to the electrodes included in the deflector.

  Hereinafter, the operation of the electron beam exposure apparatus 100 shown in FIG. 2 will be described. First, the electron beam generator 10 generates a plurality of electron beams. The electron beam generated in the electron beam generator 10 passes through the anode 13 and enters the slit deflector 15. The slit deflecting unit 15 adjusts the irradiation position of the electron beam that has passed through the anode 13 to the slit cover 11.

  The slit cover 11 shields a part of each electron beam irradiated to the slit cover 11 in order to reduce the area of the electron beam irradiated to the first molding member 14, and makes the cross section of the electron beam a predetermined size. Mold. The electron beam formed in the slit cover 11 is irradiated onto the first forming member 14 and further formed. The electron beam that has passed through the first molding member 14 has a rectangular cross-sectional shape corresponding to the shape of the opening included in the first molding member 14.

  The first multi-axis electron lens 16 independently focuses a plurality of electron beams formed in a rectangular shape in the first shaping member 14 and independently adjusts the focus of the electron beam with respect to the second shaping member 22 for each electron beam. . In addition, the first lens intensity adjusting unit 17 corrects the focal position of each electron beam incident on the lens opening of the first multi-axis electron lens 16, and the lens intensity at each lens opening of the first electron lens 16. Adjust.

  The first shaping deflection unit 18 independently deflects the plurality of electron beams shaped in a rectangular shape in the first shaping member 14 for each electron beam so as to irradiate a desired position with respect to the second shaping member. The second shaping deflection unit 20 independently deflects the plurality of electron beams deflected by the first shaping deflection unit 18 for each electron beam so as to irradiate the second shaping member 22 in a substantially vertical direction. As a result, the electron beam is irradiated onto the second molding member 22 at a desired position substantially perpendicularly to the second molding member 22.

  The second forming member 22 including a plurality of openings having a rectangular shape has a desired rectangular cross-sectional shape to be irradiated to the wafer 44 by a plurality of electron beams having a rectangular cross-sectional shape irradiated to each opening. Further shaping into an electron beam.

  The second multi-axis electron lens 24 focuses a plurality of electron beams independently, and independently adjusts the focus of the electron beam with respect to the blanking electrode array 26 for each electron beam. Further, the second lens intensity adjusting unit 25 corrects the focal position of each electron beam incident on the lens opening of the second multi-axis electron lens 24, and the lens intensity at each lens opening of the second electron lens 24. Adjust. The electron beam whose focus is adjusted by the second multi-axis electron lens 24 is incident on a plurality of apertures included in the blanking electrode array 26.

  The blanking electrode array control unit 86 controls whether or not to apply a voltage to the deflection electrode provided in the vicinity of each aperture formed in the blanking electrode array 26. The blanking electrode array 26 switches whether to irradiate the wafer 44 with the electron beam based on the voltage applied to the deflection electrode. When a voltage is applied, the electron beam that has passed through the aperture of the blanking electrode array 26 is deflected, cannot pass through the opening included in the electron beam shielding member 28, and is not irradiated onto the wafer 44. When no voltage is applied, the electron beam that has passed through the aperture is not deflected, can pass through the opening included in the electron beam shielding member 28, and the electron beam is irradiated onto the wafer 44.

  The third multi-axis electron lens 34 adjusts the rotation of the electron beam that has passed through the blanking electrode array 26. Specifically, the third multi-axis electron lens 34 adjusts the rotation of the image of the electron beam irradiated on the wafer 44 with respect to the optical axis of the electron beam. The third lens strength adjusting unit 35 adjusts the lens strength at each lens opening of the third multi-axis electron lens. Specifically, the third lens intensity adjusting unit 35 is configured to open each lens opening of the third multi-axis electron lens 34 in order to make the rotation of the image of each electron beam incident on the third multi-axis electron lens 34 uniform. Adjust the lens strength in the area. The fourth multi-axis electron lens 36 reduces the irradiation diameter of the incident electron beam.

  The fourth lens intensity adjustment unit 37 adjusts the lens intensity at each lens opening of the fourth multi-axis electron lens 36 so that the reduction ratios of the electron beams are substantially the same. Of the electron beams that have passed through the third multi-axis electron lens 34 and the fourth multi-axis electron lens 36, an electron beam that is not deflected by the blanking electrode array 26 passes through the electron beam shielding member 28 and enters the deflection unit 60. To do.

  The deflection control unit 98 controls a plurality of deflectors included in the deflection unit 60 independently. The deflecting unit 60 deflects the plurality of electron beams incident on the plurality of deflectors to a desired position on the wafer 44 independently for each electron beam. Further, the fifth multi-axis electron lens 62 independently adjusts the focal point of the electron beam incident on the deflection unit 60 with respect to the wafer 44. Then, the electron beam that has passed through the deflection unit 60 and the fifth multi-axis electron lens 62 is irradiated onto the wafer 44.

  During the exposure process, the wafer stage control unit 96 moves the wafer stage 48 in a certain direction. The blanking electrode array control unit 86 determines apertures through which the electron beam passes based on the exposure pattern data, and performs power control on each aperture. As the wafer 44 moves, the aperture through which the electron beam passes is appropriately changed, and the electron beam is deflected by the main deflecting unit 42 and the deflecting unit 60 to expose the wafer 44 with a desired circuit pattern. it can.

  FIG. 3 is a plan view of the first multi-axis electron lens 16 which is an electron lens of the electron beam exposure apparatus shown in FIG. The second multi-axis electron lens 24, the third multi-axis electron lens 34, the fourth multi-axis electron lens 36, and the fifth multi-axis electron lens 62 included in the electron beam exposure apparatus 100 are also included in the first multi-axis electron lens 16. The configuration of the multi-axis electron lens will be described below based on the configuration of the first multi-axis electron lens 16 as a representative.

  The first multi-axis electron lens 16 includes a lens unit 202 having a lens opening 204 through which an electron beam passes, and a coil unit 200 that is provided around the lens unit 202 and generates a magnetic field.

  FIG. 4 is a cross-sectional view of the first multi-axis electron lens 16. As shown in FIG. 4, the first multi-axis electron lens 16 includes a coil 214 that generates a magnetic field, and a coil part magnetic conductor part 212 provided around the coil 214. The lens unit 202 includes a plurality of lens unit magnetic conductors 210 and a plurality of openings provided in the lens unit magnetic conductors 210. The plurality of openings included in the plurality of lens unit magnetic conductors 210 form a lens opening 204 through which the electron beam passes.

  4, the lens unit 202 includes a first lens unit magnetic conductor 210a provided with a plurality of openings, and a second lens unit magnetic conductor 210b provided with a plurality of openings. The first lens part magnetic conductor part 210a and the second lens part magnetic conductor part 210b are preferably arranged substantially in parallel with the nonmagnetic conductor part 208 interposed therebetween. A magnetic field that adjusts the focus and / or rotation of the electron beam in the lens opening 204 formed by a plurality of openings provided in the first lens unit magnetic conductor 210a and the second lens unit magnetic conductor 210b. It is formed. Then, the electron beam incident on the lens opening 204 is influenced by a magnetic field generated between the plurality of lens unit magnetic conductors 210, and the focus and the like are adjusted independently without forming a crossover with each other.

  An inspection apparatus using a multi-beam electron beam is described in Japanese Patent Application Laid-Open No. 2001-308154 (Patent Document 2).

Patent re-publication WO01 / 075951 JP 2001-308154 A

  However, conventionally, as described in Patent Document 1, a lens opening 204 that allows an electron beam to pass therethrough and performs a lens action has been formed inside the coil 214. Therefore, if the number of lens openings 204 is increased, the diameter of the coil 214 increases accordingly, resulting in a coil having a large impedance. Accordingly, there is a problem that the burden on the power supply device for controlling the lens field is increased.

  As shown in FIG. 2, the electron beam exposure apparatus is provided with a plurality of deflectors, and in addition to this, an astigmatism corrector not shown in FIG. 2 is provided. It will be arranged in a narrow area corresponding to the opening 204, which may be a heavy burden for assembly, adjustment, disassembly during maintenance, and the like.

  The present invention has been made in view of such circumstances, and the power supply device for controlling the lens field is not large, and the electronic lens member in which the arrangement of the components is easy, and the electronic lens member are used. It is an object to provide an electron beam application apparatus.

  The first means for solving the problem includes a coil embedded in the ferromagnetic body leaving a part of the outer peripheral portion, and a flange extending outward from the ferromagnetic body, and the flange Is divided into two so as to constitute the N pole and S pole of the magnetic pole, and the outer peripheral portion not embedded in the ferromagnetic body of the coil is not connected to the flange portion. The electronic lens member is characterized in that a plurality of holes for forming a lens field are provided so as to face each of the divided portions of the flange portion. Item 1).

  In this means, a coil is provided on the inner side, the coil is covered with a ferromagnetic material, a collar part extending from the ferromagnetic material to the outside is provided, and the collar part is used as a magnetic pole. That is, the collar portion is divided into two so as to constitute the N pole and the S pole of the magnetic pole, and the divided portions face each other, so that the N pole and the S pole face each other. . A hole for forming a lens field is provided in each of the divided parts of the collar so as to face each other, and the lens action is received by passing an electron beam through this part. Yes.

  According to this means, since the coil is provided inside the collar portion constituting the magnetic pole, the size of the coil can be reduced and the impedance can be reduced, so that the power supply device can be small, and the lens field can be controlled. Becomes easier.

  Moreover, since the collar part which comprises a magnetic pole exists in the outer side, this part can be taken widely, Therefore The restrictions of the space which attaches components, such as an electron beam exposure apparatus, become loose.

  A second means for solving the above problem is an electron beam exposure apparatus that exposes a sensitive substrate such as a wafer with an electron beam, the electron beam generating apparatus generating a plurality of electron beams, and the plurality of electrons. An electron beam application apparatus comprising: an electron lens member as the first means arranged so as to pass each of the lines through a plurality of holes constituting the corresponding lens field (Claim 2). It is.

  According to the present invention, it is possible to provide an electron lens member in which the power supply device for controlling the lens field is not large and the arrangement of the components is easy, and an electron beam application apparatus using the electron lens member. it can.

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. 1A and 1B are schematic views showing the configuration of a multi-beam electron lens member according to an embodiment of the present invention. FIG. 1A is a plan view and FIG. 1B is a central sectional view.

  The electron lens member has a coil 1 formed at the center thereof and is embedded in the ferromagnetic body 2. The outer peripheral portion of the ferromagnetic body 2 is divided into two to form flange portions 2a and 2b. A plurality of lens openings 3a and 3b are formed in the flanges 2a and 2b, respectively, and the positions of the lens openings 3a and 3b viewed in a plan view are matched.

  Due to the magnetic force generated by the coil 1, for example, the flange portion 2a forms an N pole and the flange portion 2b forms an S pole. With this configuration, the N pole and the S pole face each other. Note that the ferromagnetic body 2 does not cover a part of the outer peripheral portion of the coil 1 in the shape of an annular zone, and therefore the flange portions 2a and 2b are also branched from this portion.

  As can be seen by comparing FIG. 1 and FIG. 4, in FIG. 4, the coil is formed so as to surround the lens opening, whereas in FIG. 1, the coil 1 is formed on the inside and the outside thereof. The lens openings 3a and 3b are formed in the lens. Therefore, the coil 1 is small in size and has a small impedance, so that it can be driven by a small power source and the lens field can be easily controlled. In FIG. 1, the lens openings 3a and 3b are formed on the outside of the coil 1. As a result, the space to be formed is widened. In FIG. 1, the ferromagnetic body 2 and the flange portions 2 a and 2 b are integrated. Needless to say.

  The basic configuration of the electron beam exposure apparatus according to the embodiment of the present invention is not different from that shown in FIG. 2, but the multi-beam electron lens member is as shown in FIG. The only difference is that the description is omitted. Of course, since the place where the electron beam passes differs, it is necessary to change the configuration shown in FIG. 2 in accordance with it. However, the part to be changed and the method thereof will be obvious to those skilled in the art.

  The electron lens member of the present invention can be widely used not only in an electron beam exposure apparatus but also in an electron beam application apparatus such as an inspection apparatus using an electron beam. At that time, for example, the structure of the electron lens shown in Patent Document 2 may be changed to the electron lens member of the present invention, and the arrangement of the electron beam source and the deflector may be changed accordingly. It is a design matter that can be done.

It is a schematic diagram which shows the structure of the electron lens member for multi beams used for the electron beam exposure apparatus which is embodiment of this invention. It is a figure which shows the structure of the electron beam exposure apparatus described in patent document 1. FIG. It is a top view of the electron lens member of the electron beam exposure apparatus shown in FIG. It is sectional drawing of the electronic lens member shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Coil, 2 ... Ferromagnetic material, 2a, 2b ... Gutter part, 3a, 3b ... Lens opening part

Claims (2)

A coil embedded in a ferromagnetic body leaving a part of the outer periphery, and a flange extending outward from the ferromagnetic body, the flange forming the N pole and S pole of the magnetic pole In addition, the outer peripheral portion of the coil that is not embedded in the ferromagnetic material is divided into two so as not to be connected by the flange portion, and the divided portions face each other to form a lens field. An electron lens member, wherein a plurality of holes are provided so as to face each of the divided portions of the flange portion. An apparatus using an electron beam, the electron beam generating apparatus for generating a plurality of electron beams, and each of the plurality of electron beams is arranged to pass through a plurality of holes constituting the corresponding lens field. An electron beam application apparatus comprising the electron lens member according to claim 1.

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