Ion implantation device and measuring device

Abstract

This invention relates to an ion implantation apparatus and a measuring apparatus to prevent a decrease in measurement accuracy caused by the generation of secondary electrons. The ion implantation apparatus includes a measuring device (62) for measuring the angular distribution of an ion beam irradiating a wafer. The measuring device (62) includes: a slit (66) on which an ion beam is incident; a central electrode body (70) having a beam measuring surface (74) disposed on a center line (C) extending from the slit (66) toward a beam travel direction that serves as a reference for the ion beam; a plurality of side electrode bodies (80a to 80f) disposed between the slit (66) and the central electrode body (70), and each having a beam measuring surface (78a to 78f) disposed away from the center line (C) in the slit width direction of the slit (66); and a magnet device (90) for applying a magnetic field bent axially about the slit length direction of the slit (66) to at least one of the plurality of side electrode bodies (80a to 80f).

Description

Technical Field

[0001] This application claims priority based on Japanese Patent Application No. 2018-247339 filed on December 28, 2018. The entire contents of the Japanese patent application are incorporated herein by reference.

[0002] The invention relates to an ion implantation device and a measuring device. Background Art

[0003] In the semiconductor manufacturing process, for the purpose of changing the conductivity of the semiconductor, changing the crystal structure of the semiconductor, etc., a step of implanting ions into a semiconductor wafer (also referred to as an ion implantation step) is standardly implemented. It is known that in the ion implantation step, the interaction between the ion beam and the wafer changes according to the angle of the ion beam irradiated on the wafer, thereby affecting the processing result of the ion implantation. Therefore, the angular distribution of the ion beam is measured before the ion implantation. For example, a plurality of electrodes arranged along the slit width direction are used to measure the current value of the beam passing through the slit, thereby obtaining the angular distribution in the slit width direction (for example, refer to Patent Document 1).

[0004] Patent Document 1: Japanese Patent Application Publication No. 2017-174505

[0005] If an ion beam is irradiated to the electrode of the measuring device, secondary electrons may be generated from the electrode. If secondary electrons are generated, the measured charge amount changes according to the amount of secondary electrons generated, which may lead to measurement errors. For example, in a structure in which a plurality of electrodes are arranged to measure the angular distribution, there is also a situation in which secondary electrons are incident on an electrode different from the electrode that generates secondary electrons, such as an adjacent electrode. In this way, the charge amount measured in both the electrode that generates secondary electrons and the electrode to which the secondary electrons are incident changes due to the secondary electrons, resulting in a measurement error of the angular distribution. Summary of the invention

[0006] One of the exemplary objects of one embodiment of the present invention is to provide a technology for preventing a decrease in measurement accuracy due to generation of secondary electrons.

[0007] An ion implantation device according to one embodiment of the present invention is provided with a measuring device for measuring the angular distribution of an ion beam irradiated on a wafer, wherein the measuring device comprises: a slit into which the ion beam is incident; a central electrode body having a beam measuring surface arranged on a center line extending from the slit to a beam serving as a reference for the ion beam and in a direction of travel of the beam; a plurality of side electrode bodies arranged between the slit and the central electrode body and each having a beam measuring surface arranged away from the center line in a slit width direction of the slit; and a magnet device for applying a magnetic field bent around an axis in a slit length direction of the slit to at least one beam measuring surface of the plurality of side electrode bodies.

[0008] Another embodiment of the present invention is a measuring device. The device is a measuring device for measuring the angular distribution of an ion beam, and the measuring device comprises: a slit into which the ion beam is incident; a central electrode body having a beam measuring surface arranged on a center line extending from the slit to a beam travel direction that serves as a reference for the ion beam; a plurality of side electrode bodies arranged between the slit and the central electrode body, and each having a beam measuring surface arranged away from the center line in a slit width direction of the slit; and a magnet device for applying a magnetic field curved around an axis in a slit length direction of the slit to at least one beam measuring surface of the plurality of side electrode bodies.

[0009] In addition, any combination of the above-mentioned constituent elements, constituent elements of the present invention, and the contents of expression may be replaced with each other between methods, apparatuses, systems, etc., and these may also be practiced as additional modes of the present invention.

[0010] Effects of the Invention

[0011] According to the present invention, it is possible to improve the measurement accuracy of a beam angle distribution measuring device. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a top view showing a schematic structure of the ion implantation apparatus according to the embodiment.

[0013] Figure 2 Yes means Figure 1 A side view of the schematic structure of an ion implantation apparatus.

[0014] Figure 3 It is an external perspective view showing a schematic structure of a measuring device according to an embodiment.

[0015] Figure 4 It is a cross-sectional view showing the structure of the measuring device in detail.

[0016] Figure 5 It is a diagram showing the range of the beam measurement surface of each electrode body.

[0017] Figure 6 This is a diagram showing an example of the distribution of the magnetic field applied to each electrode body.

[0018] Figure 7 This is a diagram showing an example of the distribution of the magnetic field applied to the side electrode body in detail.

[0019] Figure 8 This is a diagram showing an example of the distribution of the magnetic field applied to the central electrode body in detail.

[0020] In the figure: 10-ion implantation device, 62-measuring device, 66-slit, 70-central electrode body, 71-base, 72-extension part, 74, 78-beam measuring surface, 80-side electrode body, 81-main body, 82-upstream extension part, 83-downstream extension part, 90-magnet device, C-center line. DETAILED DESCRIPTION

[0021] Hereinafter, the mode for implementing the present invention will be described in detail with reference to the accompanying drawings. In addition, the same elements are marked with the same symbols in the accompanying drawings, and repeated descriptions are appropriately omitted. Moreover, the structure described below is for illustration only and does not limit the scope of the present invention in any way.

[0022] Before describing the embodiment in detail, an overview is given. The present embodiment is an ion implantation device having a measuring device for measuring the angular distribution of an ion beam irradiated on a wafer. The measuring device comprises: a slit into which an ion beam is incident; a central electrode body having a beam measuring surface arranged on a center line extending from the slit to a beam travel direction serving as a reference for the ion beam; a plurality of side electrode bodies arranged between the slit and the central electrode body, and each having a beam measuring surface arranged away from the center line in a slit width direction of the slit; and a magnet device for applying a magnetic field bent around an axis in a slit length direction of the slit to at least one beam measuring surface of the plurality of side electrode bodies. According to the present embodiment, an appropriate magnetic field is applied to the beam measuring surface of the side electrode body, thereby preferably preventing a decrease in measurement accuracy caused by secondary electrons generated by the ion beam incident on the beam measuring surface.

[0023] Figure 1 FIG. 1 is a top view schematically showing an ion implantation apparatus 10 according to an embodiment. Figure 2 1 is a side view showing a schematic structure of the ion implantation apparatus 10. The ion implantation apparatus 10 is configured to perform ion implantation on the surface of a workpiece W. The workpiece W is, for example, a substrate, such as a semiconductor wafer. For ease of explanation, the workpiece W is sometimes referred to as a wafer W in this specification, but this does not mean that the object of the implantation process is limited to a specific object.

[0024] The ion implantation device 10 is configured to scan the beam back and forth in one direction, and to make the wafer W move back and forth in a direction orthogonal to the scanning direction, thereby irradiating the entire processing surface of the wafer W with the ion beam. In this specification, for the sake of convenience, the travel direction of the ion beam traveling along the designed beam line A is defined as the z direction, and the surface perpendicular to the z direction is defined as the xy plane. When the ion beam scans the processed object W, the scanning direction of the beam is set to the x direction, and the direction perpendicular to the z direction and the x direction is set to the y direction. Therefore, the reciprocating scanning of the beam is performed along the x direction, and the reciprocating movement of the wafer W is performed along the y direction.

[0025] The ion implantation apparatus 10 includes an ion source 12, a beam line device 14, an implantation processing chamber 16, and a wafer conveying device 18. The ion source 12 is configured to provide an ion beam to the beam line device 14. The beam line device 14 is configured to convey an ion beam from the ion source 12 to the implantation processing chamber 16. The implantation processing chamber 16 accommodates a wafer W to be implanted, and performs an implantation process in which the ion beam provided from the beam line device 14 is irradiated to the wafer W. The wafer conveying device 18 is configured to carry an unprocessed wafer before implantation processing into the implantation processing chamber 16, and to carry a processed wafer after implantation processing out of the implantation processing chamber 16. The ion implantation apparatus 10 includes a vacuum exhaust system (not shown) for providing a desired vacuum environment for the ion source 12, the beam line device 14, the implantation processing chamber 16, and the wafer conveying device 18.

[0026] The beam line device 14 includes a mass analyzer 20, a beam park device 24, a beam shaper 30, a beam scanner 32, a beam parallelizer 34, and an angular energy filter (AEF) 36 in order from the upstream side of the beam line A. In addition, the upstream of the beam line A refers to the side close to the ion source 12, and the downstream of the beam line A refers to the side close to the implantation processing chamber 16 (or the beam stopper 46).

[0027] The mass spectrometer 20 is provided downstream of the ion source 12 and is configured to select necessary ion species from the ion beam extracted from the ion source 12 by mass analysis. The mass spectrometer 20 includes a mass spectrometer magnet 21 , a mass spectrometer lens 22 , and a mass spectrometer slit 23 .

[0028] The mass analysis magnet 21 applies a magnetic field to the ion beam extracted from the ion source 12 and deflects the ion beam to different paths according to the value of the mass-to-charge ratio M=m / q (m is mass, q is charge) of the ions. For example, the mass analysis magnet 21 applies a magnetic field in the y direction (e.g., -y direction) to the ion beam and deflects the ion beam in the x direction. The magnetic field strength of the mass analysis magnet 21 is adjusted so that ion species having a desired mass-to-charge ratio M pass through the mass analysis slit 23.

[0029] The mass analysis lens 22 is disposed downstream of the mass analysis magnet 21 and is configured to adjust the convergence / divergence force on the ion beam. The mass analysis lens 22 adjusts the convergence position of the beam travel direction (z direction) of the ion beam passing through the mass analysis slit 23, and adjusts the mass resolution M / dM of the mass analysis unit 20. In addition, the mass analysis lens 22 is not an essential structure, and the mass analysis lens 22 may not be provided in the mass analysis unit 20.

[0030] The mass analysis slit 23 is provided downstream of the mass analysis lens 22 and at a position away from the mass analysis lens 22. The mass analysis slit 23 is configured such that the beam deflection direction (x direction) becomes the slit width by the mass analysis magnet 21 and has an opening 23a that is relatively short in the x direction and relatively long in the y direction.

[0031] The mass analysis slit 23 may be configured such that the slit width is variable in order to adjust the mass resolution. The mass analysis slit 23 is composed of two shielding bodies that can move in the slit width direction, and is configured such that the slit width can be adjusted by changing the interval between the two shielding bodies. The mass analysis slit 23 may be configured such that the slit width is variable by switching to any one of a plurality of slits with different slit widths.

[0032] The beam stopping device 24 is configured to temporarily withdraw the ion beam from the beam line A to shield the ion beam from the downstream implantation processing chamber 16 (or wafer W). The beam stopping device 24 can be arranged at any position in the middle of the beam line A, for example, between the mass analysis lens 22 and the mass analysis slit 23. A certain distance is required between the mass analysis lens 22 and the mass analysis slit 23, so by arranging the beam stopping device 24 therebetween, the length of the beam line A can be shortened compared to the case where it is arranged at other positions, thereby achieving the overall miniaturization of the ion implantation device 10.

[0033] The beam station device 24 includes a pair of station electrodes 25 (25a, 25b) and a beam damper 26. The pair of station electrodes 25a, 25b are opposed to each other across the beam line A, and are opposed to each other in a direction (y direction) orthogonal to the beam deflection direction (x direction) of the mass analyzer magnet 21. The beam damper 26 is provided at a position downstream of the beam line A than the station electrodes 25a, 25b, and is separated from the beam line A in the opposing direction of the station electrodes 25a, 25b.

[0034] The first resident electrode 25a is arranged at a position above the beam line A in the direction of gravity, and the second resident electrode 25b is arranged at a position below the beam line A in the direction of gravity. The beam damper 26 is provided at a position farther from the beam line A in the direction of gravity than the beam line A, and is arranged at a position below the opening 23a of the mass analysis slit 23 in the direction of gravity. The beam damper 26 is, for example, formed of a portion of the opening 23a of the mass analysis slit 23 where the opening 23a is not formed. The beam damper 26 may be formed separately from the mass analysis slit 23.

[0035] The beam dwelling device 24 deflects the ion beam by using an electric field applied between a pair of dwelling electrodes 25 a and 25 b so as to make the ion beam retreat from the beam line A. For example, a negative voltage is applied to the second dwelling electrode 25 b based on the potential of the first dwelling electrode 25 a, thereby deflecting the ion beam downward in the gravity direction from the beam line A and causing the ion beam to enter the beam damper 26. Figure 2 , the dotted line indicates the trajectory of the ion beam toward the beam damper 26. The beam dwelling device 24 sets the pair of dwelling electrodes 25a and 25b to the same potential, thereby causing the ion beam to pass through the downstream side along the beam line A. The beam dwelling device 24 is configured to be able to switch between a first mode in which the ion beam passes through the downstream side and a second mode in which the ion beam is incident on the beam damper 26.

[0036] An injector Faraday cup 28 is provided downstream of the mass analysis slit 23. The injector Faraday cup 28 is configured to be able to enter and exit the beam line A by the operation of the injector drive unit 29. The injector drive unit 29 moves the injector Faraday cup 28 in a direction (e.g., y direction) orthogonal to the direction in which the beam line A extends. Figure 2 As shown by the dotted line in FIG. 2 , when the implanter Faraday cup 28 is arranged on the beam line A, the ion beam directed toward the downstream side is shielded. Figure 2 As shown by the solid line in FIG. 2 , when the implanter Faraday cup 28 withdraws from the beam line A, the shielding of the ion beam toward the downstream side is released.

[0037] The implanter Faraday cup 28 is configured to measure the beam current of the ion beam that has been mass analyzed by the mass spectrometer 20. The implanter Faraday cup 28 measures the beam current while changing the magnetic field strength of the mass analysis magnet 21, thereby being able to measure the mass analysis spectrum of the ion beam. The mass resolution of the mass spectrometer 20 can be calculated using the measured mass analysis spectrum.

[0038] The beam shaping unit 30 includes a convergence / divergence lens such as a quadrupole convergence / divergence device (Q lens), and is configured to shape the ion beam that has passed through the mass analyzer 20 into a desired cross-sectional shape. The beam shaping unit 30 is, for example, composed of an electric field type three-stage quadrupole lens (also called a triple Q lens), and has three quadrupole lenses 30a, 30b, and 30c. The beam shaping unit 30 can independently adjust the convergence or divergence of the ion beam in the x-direction and the y-direction by using the three quadrupole lenses 30a to 30c. The beam shaping unit 30 may include a magnetic field type lens device, or may include a lens device that uses both an electric field and a magnetic field to shape the beam.

[0039] The beam scanning unit 32 is a beam deflection device configured to provide a reciprocating scan of the beam and scan the shaped ion beam in the x direction. The beam scanning unit 32 has a pair of scanning electrodes facing each other in the beam scanning direction (x direction). The scanning electrode pair is connected to a variable voltage power supply (not shown), and the voltage applied between the scanning electrode pair is periodically changed to change the electric field generated between the electrodes, so as to deflect the ion beam to various angles. As a result, the ion beam is scanned over the entire scanning range in the x direction. Figure 1 In FIG. 1 , the scanning direction and scanning range of the beam are exemplified by arrow X, and a plurality of trajectories of the ion beam within the scanning range are indicated by single-dot chain lines.

[0040] The beam parallelization unit 34 is configured to make the traveling direction of the scanned ion beam parallel to the trajectory of the designed beam line A. The beam parallelization unit 34 has a plurality of parallelization lens electrodes in the shape of an arc with a slit for passing the ion beam in the center. The parallelization lens electrodes are connected to a high voltage power supply (not shown) and apply an electric field generated by the application of voltage to the ion beam to align the traveling direction of the ion beam in parallel. In addition, the beam parallelization unit 34 can be replaced by other beam parallelization devices, and the beam parallelization device can also be configured as a magnet device using a magnetic field.

[0041] An AD (Accel / Decel) column (not shown) for accelerating or decelerating the ion beam may be provided downstream of the beam parallelizing unit 34 .

[0042] The angle energy filter (AEF) 36 is configured to analyze the energy of the ion beam and deflect ions of required energy downward to introduce them into the implantation chamber 16. The angle energy filter 36 has an AEF electrode pair for electric field deflection. The AEF electrode pair is connected to a high voltage power supply (not shown). Figure 2 In the embodiment, a positive voltage is applied to the upper AEF electrode and a negative voltage is applied to the lower AEF electrode to deflect the ion beam downward. In addition, the angle energy filter 36 can be composed of a magnetic device for magnetic field deflection or a combination of an AEF electrode pair for electric field deflection and a magnetic device.

[0043] In this manner, the beam line device 14 supplies the ion beam to be irradiated to the wafer W to the implantation processing chamber 16 .

[0044] The implantation chamber 16 includes an energy slit 38, a plasma shower device 40, a side cup 42, a center cup 44, and a beam stopper 46 in order from the upstream side of the beam line A. Figure 2 As shown, the implantation processing chamber 16 includes a platen driving device 50 for holding one or more wafers W.

[0045] The energy slit 38 is disposed on the downstream side of the angle energy filter 36, and performs energy analysis of the ion beam incident on the wafer W together with the angle energy filter 36. The energy slit 38 is an energy defining slit (EDS; Energy Defining Slit) composed of a slit that is horizontally long along the beam scanning direction (x direction). The energy slit 38 allows the ion beam of the desired energy value or energy range to pass toward the wafer W, and shields the ion beams other than this.

[0046] The plasma spray device 40 is located on the downstream side of the energy slit 38. The plasma spray device 40 supplies low-energy electrons to the ion beam and the surface (wafer processing surface) of the wafer W according to the beam current of the ion beam, thereby suppressing the positive charge of the wafer processing surface caused by ion implantation. The plasma spray device 40 includes, for example, a spray pipe through which the ion beam passes and a plasma generating device that supplies electrons into the spray pipe.

[0047] The side cups 42 (42R, 42L) are configured to measure the beam current of the ion beam during the process of implanting ions into the wafer W. Figure 2 As shown, the side cups 42R and 42L are arranged to be staggered to the left and right (x direction) relative to the wafer W arranged on the beam line A, and are arranged at a position that does not shield the ion beam toward the wafer W during ion implantation. The ion beam is scanned in the x direction beyond the range where the wafer W is located, so even during ion implantation, a part of the scanned beam will be incident on the side cups 42R and 42L. Therefore, the beam current amount in the ion implantation process is measured by the side cups 42R and 42L.

[0048] The center cup 44 is configured to measure the beam current on the wafer processing surface. The center cup 44 is configured to be movable by the operation of the driving unit 45, and to retreat from the implantation position where the wafer W is located when ions are implanted, and to be inserted into the implantation position when the wafer W is not at the implantation position. The center cup 44 measures the beam current while moving in the x direction, thereby being able to measure the beam current over the entire beam scanning range in the x direction. The center cup 44 can be formed into an array shape by arranging a plurality of Faraday cups in parallel in the x direction, so that the beam current at a plurality of positions in the beam scanning direction (x direction) can be measured simultaneously.

[0049] At least one of the side cup 42 and the center cup 44 may include a single Faraday cup for measuring the amount of beam current, or may include an angle meter for measuring the angle information of the beam. The angle meter, for example, includes a slit and a plurality of current detection units arranged away from the slit in the beam travel direction (z direction). For example, the beam passing through the slit is measured using a plurality of current detection units arranged in the slit width direction, thereby being able to measure the angle component of the beam in the slit width direction. At least one of the side cup 42 and the center cup 44 may include a first angle meter capable of measuring the angle information in the x direction and a second angle meter capable of measuring the angle information in the y direction.

[0050] The platen driving device 50 includes a wafer holding device 52, a reciprocating motion mechanism 54, a torsion angle adjustment mechanism 56, and a tilt angle adjustment mechanism 58. The wafer holding device 52 includes an electrostatic chuck for holding the wafer W. The reciprocating motion mechanism 54 reciprocates the wafer held by the wafer holding device 52 along the y direction by causing the wafer holding device 52 to reciprocate along the reciprocating motion direction (y direction) orthogonal to the beam scanning direction (x direction). In FIG. 2, the reciprocating motion of the wafer W is illustrated by arrow Y.

[0051] The torsion angle adjustment mechanism 56 is a mechanism for adjusting the rotation angle of the wafer W. The torsion angle between the alignment mark provided on the periphery of the wafer and the reference position is adjusted by rotating the wafer W with the normal line of the wafer processing surface as the axis. Here, the alignment mark of the wafer refers to a notch or an orientation plane provided on the periphery of the wafer, and refers to a mark that serves as a reference for the crystal axis direction of the wafer and the angular position of the circumferential direction of the wafer. The torsion angle adjustment mechanism 56 is provided between the wafer holding device 52 and the reciprocating motion mechanism 54, and reciprocates together with the wafer holding device 52.

[0052] The tilt angle adjustment mechanism 58 is a mechanism for adjusting the slope of the wafer W, which adjusts the tilt angle (Tilt angle) between the traveling direction of the ion beam toward the wafer processing surface and the normal line of the wafer processing surface. In this embodiment, the angle of the tilt angle of the wafer W with the axis in the x direction as the central axis of rotation is adjusted as the tilt angle. The tilt angle adjustment mechanism 58 is arranged between the reciprocating motion mechanism 54 and the wall surface of the implantation processing chamber 16, and is configured to adjust the tilt angle of the wafer W by rotating the platen driving device 50 including the reciprocating motion mechanism 54 as a whole in the R direction.

[0053] The platen driving device 50 holds the wafer W so that the wafer W can be moved between an implantation position where the wafer W is irradiated with an ion beam and a transfer position where the wafer W is transferred into or out of the wafer transfer device 18 . Figure 2The state where the wafer W is located at the implantation position is indicated, and the platen driving device 50 holds the wafer W in such a manner that the beam line A intersects the wafer W. The conveying position of the wafer W corresponds to the position of the wafer holding device 52 when the wafer W is carried in or out through the conveying port 48 by the conveying mechanism or conveying robot provided in the wafer conveying device 18.

[0054] The beam stopper 46 is disposed at the most downstream of the beam line A, for example, mounted on the inner wall of the implantation processing chamber 16. When the wafer W is not on the beam line A, the ion beam is incident on the beam stopper 46. The beam stopper 46 is located near a transfer port 48 connecting the implantation processing chamber 16 and the wafer transfer device 18, and is disposed at a position vertically lower than the transfer port 48.

[0055] The ion implantation apparatus 10 includes a central control device 60. The central control device 60 controls the overall operation of the ion implantation apparatus 10. The central control device 60 is implemented in hardware by components represented by a computer CPU and a memory, and mechanical devices, and in software by a computer program, etc. Various functions provided by the central control device 60 can be implemented by the cooperation of hardware and software.

[0056] Figure 3 : is an external perspective view showing a schematic structure of a measuring device 62 of an embodiment. The measuring device 62 includes a housing 64 and a slit 66 provided on a front surface 64a of the housing 64. A plurality of electrode bodies are provided inside the housing 64. The measuring device 62 is a device for measuring the angular distribution of an ion beam, and detects the ion beam passing through the slit 66 using a plurality of electrode bodies, and obtains the angular distribution of the ion beam based on the detection results of each electrode body. The measuring device 62 can be used, for example, at the position of the side cup 42 or the center cup 44 of the above-mentioned ion implantation device 10.

[0057] In the example shown in the figure, the traveling direction of the ion beam is defined as the z direction, the slit width direction of the slit 66 is defined as the x direction, and the slit length direction of the slit 66 is defined as the y direction, and the angle distribution in the x direction is measured by the measuring device 62. In addition, the measuring direction of the angle distribution of the measuring device 62 is not limited to the x direction, and the measuring device 62 can also be used in a manner capable of measuring the angle distribution in the y direction. Furthermore, the measuring device 62 can be used in a manner capable of measuring the angle distribution in a direction that is inclined with respect to both the x direction and the y direction.

[0058] Figure 41 is a cross-sectional view showing the structure of the measuring device 62 in detail, showing the structure of the cross section (xz plane) perpendicular to the slit length direction (y direction) of the slit 66. The measuring device 62 includes a housing 64, a central electrode body 70, a plurality of side electrode bodies 80a, 80b, 80c, 80d, 80e, 80f (also collectively referred to as side electrode bodies 80), and a magnet device 90.

[0059] The housing 64 includes a slit portion 64b, an angle limiting portion 64c, and an electrode housing portion 64d. The slit portion 64b includes a front surface 64a provided with a slit 66. The angle limiting portion 64c is provided at a position further downstream in the beam travel direction (z direction) than the slit portion 64b. The angle limiting portion 64c shields a portion of the ion beam directed toward the side electrode body 80 (e.g., the first side electrode body 80a and the second side electrode body 80b) to prevent the beam having an angle component outside the measurement range from being incident on the side electrode body 80. The electrode housing portion 64d is provided at a position further downstream in the beam travel direction (z direction) than the angle limiting portion 64c. The electrode housing portion 64d is configured to include a yoke for forming a magnetic circuit of the magnet device 90.

[0060] The central electrode body 70 is disposed on the center line C extending from the slit 66 in the beam traveling direction (z direction), and is disposed at the most downstream in the beam traveling direction away from the slit 66. The central electrode body 70 measures a beam having a zero or extremely small angle component in the slit width direction (x direction), that is, a beam that does not enter the plurality of side electrode bodies 80a to 80f and travels substantially straight along the center line C.

[0061] The central electrode body 70 includes a base 71 and a pair of extensions 72L and 72R. The base 71 is disposed on the center line C. The base 71 includes a beam measuring surface 74 exposed toward the slit 66 in the beam traveling direction. The pair of extensions 72L and 72R extend from both ends of the base 71 in the slit width direction (x direction) toward the upstream side in the beam traveling direction (z direction).

[0062] A plurality of side electrode bodies 80a to 80f are arranged between the slit 66 and the central electrode body 70, and are arranged symmetrically across the center line C in the slit width direction (x direction). In the illustrated example, six side electrode bodies 80a to 80f are provided, and three side electrode bodies are provided across the center line C. Specifically, the first side electrode body 80a and the second side electrode body 80b are arranged symmetrically across the center line C in the slit width direction (x direction), the third side electrode body 80c and the fourth side electrode body 80d are arranged symmetrically across the center line C in the slit width direction (x direction), and the fifth side electrode body 80e and the sixth side electrode body 80f are arranged symmetrically across the center line C in the slit width direction (x direction).

[0063] The first side electrode body 80a, the third side electrode body 80c, and the fifth side electrode body 80e constitute a first group of side electrode bodies arranged along the beam travel direction (z direction). The second side electrode body 80b, the fourth side electrode body 80d, and the sixth side electrode body 80f constitute a second group of side electrode bodies arranged along the beam travel direction (z direction). The second group of side electrode bodies 80b, 80d, and 80f are arranged symmetrically with the first group of side electrode bodies 80a, 80c, and 80d across the center line C in the slit width direction (x direction).

[0064] The distance d between the side electrode bodies 80a to 80f and the center line C in the slit width direction (x direction) is: a d b d c d d d e d f The further downstream the electrode body 80a and the electrode body 80b are arranged in the beam traveling direction, the smaller the distance d is from the center line C. a and b The distance d from the center line C of each of the third side electrode body 80c and the fourth side electrode body 80d is relatively large, for example, 1.5 times the slit width w of the slit 66. c and d The distance d from the center line C to each of the fifth side electrode body 80e and the sixth side electrode body 80f is about 1:1. e and f It is relatively small, for example, 0.5 times the slit width w of the slit 66 .

[0065] The plurality of side electrode bodies 80a to 80f respectively include main bodies 81a, 81b, 81c, 81d, 81e, 81f (also collectively referred to as main body 81), upstream extensions 82a, 82b, 82c, 82d, 82e, 82f (also collectively referred to as upstream extensions 82), and downstream extensions 83a, 83b, 83c, 83d, 83e, 83f (also collectively referred to as downstream extensions 83). The plurality of side electrode bodies 80a to 80f respectively include beam measuring surfaces 78a, 78b, 78c, 78d, 78e, 78f (also collectively referred to as beam measuring surfaces 78) on which the beam passing through the slit 66 can be incident.

[0066] The main body 81 is a portion that protrudes in the slit width direction (x direction) toward the center line C. Therefore, the distance from the center line C to the main body 81 (for example, the distance d a) is less than the distance from the center line C to the upstream extension portion 82 or the downstream extension portion 83. The main body portion 81 is the portion where the beam passing through the slit 66 is mainly incident. Therefore, at least a portion of the surface of the main body portion 81 constitutes at least a portion of the beam measurement surface 78 of the side electrode body 80.

[0067] The upstream extension portion 82 is a portion extending from the main body portion 81 to the upstream side. The upstream extension portion 82 is provided farther from the center line C than the main body portion 81 in the slit width direction (x direction). The downstream extension portion 83 is a portion extending from the main body portion 81 to the downstream side. The downstream extension portion 83 is provided farther from the center line C than the main body portion 81 in the slit width direction (x direction). The length of each of the upstream extension portion 82 and the downstream extension portion 83 in the beam traveling direction (z direction) is greater than the length of the main body portion 81 in the beam traveling direction (z direction).

[0068] Figure 5 It is a diagram showing the range of the beam measurement surfaces 74 and 78 of the electrode bodies 70 and 80 . Figure 5 In FIG. 1 , the range of the beam measurement surface 74 of the central electrode body 70 and the range of the beam measurement surface 78 of each of the plurality of side electrode bodies 80 are indicated by bold lines. The beam measurement surface of each electrode body is the range of the surface of each electrode body into which the beam passing through the slit 66 can be incident.

[0069] Among the beams passing through the slit 66, the beams having an angle component greater than θ in the slit width direction (x direction) are incident on the inner surface of the angle limiting portion 64c of the housing 64. As a result, the beams having an angle component greater than θ in the slit width direction (x direction) are not detected by the electrode body, and thus are outside the measurement range of the measurement device 62. On the other hand, the beams having an angle component less than θ in the slit width direction (x direction) can be incident on the central electrode body 70 or any one of the plurality of side electrode bodies 80.

[0070] The beam having a relatively large angular component can be incident on the first beam measuring surface 78a of the first side electrode body 80a or the second beam measuring surface 78b of the second side electrode body 80b. The first beam measuring surface 78a is composed of a portion of the surface of the first main body 81a and a portion of the surface of the first upstream extension 82a. On the other hand, the beam passing through the slit 66 does not impinge on the surface of the first downstream extension 83a. This is because, when viewed from the slit 66, the surface of the first downstream extension 83a is located on the back side of the first main body 81a protruding toward the center line C. In addition, the first beam measuring surface 78a can also be composed of only a portion of the surface of the first main body 81a, and the beam passing through the slit 66 does not impinge on the surface of the first upstream extension 82a. The second beam measuring surface 78b is configured to be symmetrical with the first beam measuring surface 78a across the center line C in the slit width direction.

[0071] The beam having a medium angle component can be incident on the third beam measuring surface 78c of the third side electrode body 80c or the fourth beam measuring surface 78d of the fourth side electrode body 80d. The third beam measuring surface 78c is composed of a part of the surface of the third main body 81c. On the other hand, the beam passing through the slit 66 is not incident on the surface of the third upstream extension 82c and the third downstream extension 83c. This is because, when viewed from the slit 66, the surface of the third upstream extension 82c is located on the back of the first side electrode body 80a, and the surface of the third downstream extension 83c is located on the back of the third main body 81c protruding toward the center line C. In addition, it can also be configured so that a part of the surface of the third upstream extension 82c becomes the third beam measuring surface 78c. The fourth beam measuring surface 78d is configured to be symmetrical with the third beam measuring surface 78c across the center line C in the slit width direction.

[0072] A beam having a relatively small angular component can be incident on the 5th beam measuring surface 78e of the 5th side electrode body 80e or the 6th beam measuring surface 78f of the 6th side electrode body 80f. The 5th beam measuring surface 78e is composed of a portion of the surface of the 5th main body 81e. On the other hand, the beam passing through the slit 66 is not incident on the surfaces of the 5th upstream extension 82e and the 5th downstream extension 83e. This is because, when viewed from the slit 66, the surface of the 5th upstream extension 82e is located on the back side of the 3rd side electrode body 80c, and the surface of the 5th downstream extension 83e is located on the back side of the 5th main body 81e protruding toward the center line C. In addition, it can also be configured so that a portion of the surface of the 5th upstream extension 82e becomes the 5th beam measuring surface 78e. The 6th beam measuring surface 78f is configured to be symmetrical with the 5th beam measuring surface 78e across the center line C in the slit width direction.

[0073] The beam having an angle component of substantially zero can be incident on the beam measuring surface 74 of the central electrode body 70. The beam measuring surface 74 of the central electrode body 70 is constituted by a portion of the surface of the base 71 of the central electrode body 70. In addition, at least a portion of the inner surface of the extension portions 72L and 72R of the central electrode body 70 can be constituted as the beam measuring surface 74.

[0074] The magnet device 90 is configured to apply a magnetic field to the beam measuring surfaces 74 and 78 of the central electrode body 70 and the plurality of side electrode bodies 80. The magnet device 90 includes a plurality of first magnets 91a, 91b, 91c, 91d, 91e, and 91f (also collectively referred to as first magnets 91), a plurality of second magnets 92a, 92b, 92c, 92d, 92e, and 92f (also collectively referred to as second magnets 92), two third magnets 93L and 93R (also collectively referred to as third magnets 93), and a fourth magnet 94. The magnets 91 to 94 are arranged farther from the center line C than the central electrode body 70 and the plurality of side electrode bodies 80 in the slit width direction (x direction). The magnets 91 to 94 are arranged along the inner wall surface of the electrode accommodating portion 64d of the housing 64. The arrows in the figure schematically indicate the magnetization directions of the magnets 91 to 94.

[0075] The first magnet 91 and the second magnet 92 are configured to have opposite polarities. The first magnet 91, for example, has a first magnetic pole with an N pole, and is configured so that the first magnetic pole becomes the inner side. The second magnet 92, for example, has a second magnetic pole with an S pole, and is configured so that the second magnetic pole becomes the inner side. Similarly, the third magnet 93 and the fourth magnet 94 are configured to have opposite polarities. The third magnet 93, for example, has a third magnetic pole with an N pole, and is configured so that the third magnetic pole becomes the inner side. The fourth magnet 94, for example, has a fourth magnetic pole with an S pole, and is configured so that the fourth magnetic pole becomes the inner side. In addition, the first magnetic pole and the third magnetic pole may be the S poles, and the second magnetic pole and the fourth magnetic pole may be the N poles.

[0076] A plurality of first magnets 91 and a plurality of second magnets 92 are alternately arranged in parallel along the inner wall surface of the electrode housing portion 64d of the shell 64 in the beam traveling direction, and the pairs of first magnets 91 and second magnets 92 are arranged corresponding to the plurality of side electrode bodies 80a to 80f, respectively. For example, a pair of first magnets 91a and second magnets 92a are arranged near the first side electrode body 80a. The first magnet 91 is arranged at a position closer to the upstream side than the main body 81 of the corresponding side electrode body 80, and the second magnet 92 is arranged at a position closer to the downstream side than the main body 81 of the corresponding side electrode body 80. The first magnet 91 and the second magnet 92 apply a magnetic field curved around the axis of the slit length direction (y direction) of the slit 66 to the beam measuring surface 78 of the corresponding side electrode body 80 (refer to the following description). Figure 6 and Figure 7 The plurality of first magnets 91 and the plurality of second magnets 92 are symmetrically arranged with respect to the center line C in the slit width direction (x direction), and a magnetic field having a distribution that is substantially symmetrical with respect to the center line C in the slit width direction (x direction) is applied.

[0077] The two third magnets 93L, 93R and the fourth magnet 94 are arranged near the central electrode body 70. The two third magnets 93L, 93R are symmetrically arranged in the slit width direction (x direction) across the central electrode body 70 (i.e., across the center line C). On the other hand, the fourth magnet 94 is arranged only on one side across the central electrode body 70 (i.e., across the center line C). In the example shown in the figure, the third magnet 93L and the fourth magnet 94 are arranged on the downstream side of the second magnet 92e arranged near the fifth side electrode body 80e. On the other hand, only the third magnet 93R is arranged on the downstream side of the second magnet 92f arranged near the sixth side electrode body 80f, and the fourth magnet is not arranged. As a result, the two third magnets 93L, 93R and the fourth magnet 94 apply a magnetic field that is asymmetrically distributed in the slit width direction across the center line C (refer to the following description). Figure 6 and Figure 8 ).

[0078] Figure 6 This is a diagram showing an example of the distribution of the magnetic field applied to each electrode body. Figure 6 In the figure, only the outlines of the central electrode body 70 and the plurality of side electrode bodies 80 are shown and the shaded parts are omitted to facilitate understanding of the magnetic field distribution inside each electrode body. As shown in the figure, the magnetic field lines extend from the first magnet 91 to the second magnet 92 in an arc shape. The magnetic field lines extending from the first magnet 91 to the second magnet 92 are arranged along the same Figure 6 The axis extending in a direction perpendicular to the paper plane (i.e., the y direction) is bent. Furthermore, the magnetic lines of force emitted from the beam measuring surface 78 of the side electrode body 80 are incident on the surface of the same side electrode body 80, or the magnetic lines of force incident on the beam measuring surface 78 of the side electrode body 80 are emitted from the surface of the same side electrode body 80. Furthermore, the magnetic lines of force passing through the vicinity of the beam measuring surface 78 of the side electrode body 80 are emitted from the surface of the same side electrode body 80 and are incident on the surface of the same side electrode body 80.

[0079] Figure 7 is a diagram showing in detail an example of the distribution of the magnetic field applied to the side electrode body 80, and is Figure 6 An enlarged view of the vicinity of the first side electrode body 80a. Figure 7 , as an example of the magnetic field distribution applied to the side electrode body 80, three magnetic lines of force B1, B2, and B3 between the first magnet 91 and the second magnet 92 are depicted. The magnetic lines of force B1 to B3 emitted from the first magnet 91 intersect the beam measurement surface 78 of the side electrode body 80 or pass through the vicinity of the beam measurement surface 78, and then enter the second magnet 92.

[0080] The first magnetic line of force B1 passes through the upstream extension portion 82 and is emitted from the inner side surface 86 of the upstream extension portion 82. After advancing along the center line C near the inner side surface 85 of the main body 81 constituting a part of the beam measuring surface 78, the first magnetic line of force B1 is incident on the inner side surface 87 of the downstream extension portion 83. After being emitted from the inner side surface 86 of the upstream extension portion 82, the second magnetic line of force B2 is incident on the inner side surface 85 of the main body 81 constituting a part of the beam measuring surface 78. After being emitted from the inner side surface 86 of the upstream extension portion 82, the third magnetic line of force B3 is incident on the upper surface 84 of the main body 81 constituting a part of the beam measuring surface 78. Here, the upper surface 84 of the main body 81 is directed toward the upstream side of the beam travel direction (z direction) toward the slit 66 (reference Figures 4 to 6 Furthermore, the inner side surfaces 85, 86, 87 of the main body 81, the upstream extension 82, and the downstream extension 83 are surfaces exposed toward the center line C inwardly in the slit width direction (x direction).

[0081] By setting the magnetic field distribution as shown in the figure, even when secondary electrons are generated on the beam measurement surface 78 by the incidence of the ion beam to be measured, the secondary electrons can be moved along the spiral orbits E1, E2, and E3 that are respectively wound around the magnetic lines of force B1, B2, and B3, and the secondary electrons are incident on the inner side surfaces 86 and 87 of the same side electrode body 80. That is, the inner side surfaces 86 and 87 of the same side electrode body 80 can absorb the secondary electrons generated on the beam measurement surface 78 of the side electrode body 80. As a result, the secondary electrons are absorbed by an electrode body different from the electrode body that generates the secondary electrons, and the charge transfer between different electrode bodies can be prevented from causing measurement errors. In other words, the side electrode body 80 is configured in such a way that at least a part of the inner side surfaces 86 and 87 of the upstream extension portion 82 and the downstream extension portion 83 of the side electrode body 80 become secondary electron absorption surfaces, thereby preventing the generation of measurement errors caused by secondary electrons.

[0082] As shown in the figure, the secondary electrons moving along the magnetic field lines describe a spiral orbit, so it is preferable to reduce the radius of the spiral orbit E to prevent the secondary electrons from being incident on a side electrode body (e.g., the second side electrode body 80b opposite to the center line C) different from the side electrode body (e.g., the first side electrode body 80a) that generates the secondary electrons. According to the opinions of the inventors, the energy of the secondary electrons generated on the beam measurement surface 78 by the incidence of the ion beam is less than 30eV. Therefore, it is preferable to apply a magnetic field of such intensity that the Larmor radius (Larmor radius) when the 30eV electrons perform a spiral motion is less than the distance d1 from the center line C to the side electrode body 80.

[0083] In order to Figure 7The magnetic field distribution shown is applied to the side electrode body 80, and the positions of the first magnet 91 and the second magnet 92 in the beam travel direction (z direction) need to be appropriately set. The center 95 of the first magnet 91 in the beam travel direction (z direction) needs to be arranged at a position corresponding to the upstream extension portion 82, that is, a position upstream of the beam measurement surface 78 and downstream of the upstream end 88 of the side electrode body 80. Similarly, the center 96 of the second magnet 92 in the beam travel direction (z direction) needs to be arranged at a position corresponding to the downstream extension portion 83, that is, a position downstream of the beam measurement surface 78 and upstream of the downstream end 89 of the side electrode body 80. In addition, the center 95 of the first magnet 91 is preferably arranged at a position closer to the upstream end 88 than the beam measurement surface 78. The center 96 of the second magnet 92 is preferably arranged at a position closer to the downstream end 89 than the beam measurement surface 78. Furthermore, it is preferable that the middle point of the first magnet 91 and the second magnet 92 in the beam traveling direction (z direction) coincide with the position of the beam measuring surface 78 in the beam traveling direction (z direction).

[0084] According to the side electrode body 80 of the present embodiment, the length of the main body 81 protruding toward the center line C in the beam travel direction (z direction) is small, so the range of the beam measurement surface 78 in the beam travel direction (z direction) can be reduced, and the location where secondary electrons may be generated (i.e., the beam measurement surface 78) can be limited. In other words, by setting the distances d2 and d3 of the upstream extension 82 and the downstream extension 83 from the center line C to be greater than the distance d1 of the main body 81 from the center line C, at least a portion of the inner side surface 86 of the upstream extension 82 and the entire inner side surface 87 of the downstream extension 83 can be set as a "beam non-irradiated surface" that is not irradiated by the beam. In addition, at least a portion of the inner side surfaces 86 and 87 of the upstream extension 82 and the downstream extension 83 can be set as a "secondary electron absorption surface" that absorbs secondary electrons generated on the beam measurement surface 78. Moreover, by setting the length of the upstream extension portion 82 and the downstream extension portion 83 in the beam propagation direction (z direction) to be greater than the main body portion 81, the range of the "beam non-irradiation surface" and the "secondary electron absorption surface" in the beam propagation direction (z direction) can be increased, and the secondary electrons generated on the beam measuring surface 78 can be reliably absorbed by the upstream extension portion 82 and the downstream extension portion 83.

[0085] Furthermore, the distance d3 from the center line C to the downstream extension 83 is set to be smaller than the distance d2 from the center line C to the upstream extension 82, so that the inner side surface 87 of the downstream extension 83 is as close to the beam measurement surface 78 (the inner side surface 85 of the main body 81) as possible, thereby enabling the secondary electrons heading downstream from the beam measurement surface 78 to be effectively absorbed by the inner side surface 87 of the downstream extension 83. In addition, the distance d3 from the center line C to the downstream extension 83 needs to be increased to the extent that the entire inner side surface 87 of the downstream extension 83 becomes a "beam non-irradiated surface", that is, a distance to the extent that it is hidden behind the back of the main body 81.

[0086] Figure 8 is a diagram showing an example of the magnetic field distribution applied to the central electrode body 70 in detail, and is Figure 6 An enlarged view of the vicinity of the central electrode body 70. Figure 8 , as an example of the magnetic field distribution applied to the central electrode body 70, three magnetic force lines B4, B5, and B6 between the two third magnets 93L and 93R and the fourth magnet 94 are depicted. As shown in the figure, the magnetic field distribution near the central electrode body 70 is asymmetric with respect to the center line C in the slit width direction (x direction). For example, the fourth magnetic force line B4 intersecting the beam measurement surface 74 (the surface of the base 71) is emitted from the third magnet 93R, passes through the extension 72R, and is emitted from the inner side surface 73R of the extension 72R, and is incident on the beam measurement surface 74. Thereafter, the fourth magnetic force line B4 passes through the base 71 and is incident on the fourth magnet 94.

[0087] The secondary electrons generated on the beam measurement surface 74 of the central electrode body 70 move along the spiral track E4 that winds around the fourth magnetic field line B4 and are incident on the inner side surface 73R of the extension part 72R. Therefore, at least a part of the inner side surface 73R of the extension part 72R becomes a "beam non-irradiation surface" and a "secondary electron absorption surface". By setting the magnetic field distribution to be asymmetric as shown in the figure, the secondary electrons generated on the beam measurement surface 74 can be incident on the inner side surface 73R of one extension part 72R. Assuming that the magnetic field distribution is symmetrical with respect to the center line C in the slit width direction (x direction), the magnetic field lines near the center line C extend in the direction along the center line C, so the secondary electrons generated on the beam measurement surface 74 may be separated from the central electrode body 70 more upstream along the center line C. In this way, the secondary electrons generated on the central electrode body 70 may be absorbed by the side electrode bodies 80 (for example, the fifth side electrode body 80e and the sixth side electrode body 80f) located on the upstream side of the central electrode body 70, causing measurement errors. On the other hand, according to the present embodiment, since the magnetic field distribution applied to the central electrode body 70 is asymmetric, the inner side surface 73R of one extending portion 72R can reliably absorb the secondary electrons generated near the center line C.

[0088] In addition, in order to Figure 8 In order to apply the magnetic field distribution shown in the figure to the central electrode body 70, the positions of the third magnets 93L and 93R in the beam travel direction (z direction) need to be arranged at positions corresponding to the extensions 72L and 72R, that is, at positions upstream of the beam measurement plane 74 and downstream of the upstream end 75 of the central electrode body 70. The centers 97L and 97R of the third magnets 93L and 93R in the beam travel direction (z direction) are preferably arranged at positions closer to the upstream end 75 than the beam measurement plane 74. On the other hand, the fourth magnet 94 needs to be arranged at a position further downstream than the beam measurement plane 74, and the center 98 of the fourth magnet 94 in the beam travel direction (z direction) is preferably arranged at a position further downstream than the beam measurement plane 74.

[0089] According to the measuring device 62 of the above structure, the central electrode body 70 and the plurality of side electrode bodies 80 can be used to measure the angular component of the ion beam passing through the slit 66 in the slit width direction (x direction). The magnetic field distribution applied to the plurality of side electrode bodies 80 is roughly symmetrical with respect to the center line C in the slit width direction, so the magnetic field lines near the center line C are along the direction of the center line C. As a result, the influence of the change in the trajectory of the ion beam passing near the center line C due to the application of the magnetic field can be reduced, thereby preventing the measurement error caused by the change in the beam trajectory. On the other hand, the magnetic field distribution applied to the central electrode body 70 is asymmetrical with respect to the center line C in the slit width direction, so it may affect the trajectory of the ion beam passing near the center line C, but the beam passing near the central electrode body 70 is detected by the central electrode body 70, so it will not cause measurement errors. Therefore, according to this embodiment, by applying a magnetic field to each electrode body, it is preferably possible to prevent the generation of measurement errors caused by secondary electrons, thereby improving the measurement accuracy of the angular distribution of the ion beam.

[0090] The present invention has been described above with reference to the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments, and the contents of the embodiments may be appropriately combined or replaced. Furthermore, according to the knowledge of those skilled in the art, the combination or processing sequence of the embodiments may be appropriately changed or various design changes may be made to the embodiments, and the embodiments with such modifications may also be included in the scope of the present invention.

[0091] In the above embodiment, with respect to the potential of the housing 64 (slit 66) (e.g., ground potential), a negative voltage may be applied to the central electrode body 70 and the plurality of side electrode bodies 80. The absolute value of the negative bias voltage applied to the central electrode body 70 and the plurality of side electrode bodies 80 may be 30 V or more. In other words, the negative bias voltage may be -30 V or less. For example, the energy of the ion beam to be measured is set to E B, when the charge of the ion is set to q, the absolute value can be applied to become E B By applying a negative bias voltage to the central electrode body 70 and the plurality of side electrode bodies 80, it is possible to preferably prevent secondary electrons generated on the inner surface of the angle limiting portion 64c due to the incidence of the ion beam from flowing into at least one of the central electrode body 70 and the plurality of side electrode bodies 80. As a result, the measurement accuracy of the measuring device 62 can be further improved.

[0092] In the above embodiment, a structure is set to apply a magnetic field to both the central electrode body 70 and the plurality of side electrode bodies 80. In a modified example, a structure may be set to apply a magnetic field only to a portion of the central electrode body 70 and the plurality of side electrode bodies 80. For example, a magnetic field may be applied only to a portion of the electrode bodies where the measurement error caused by the generation of secondary electrons is more significant.

Claims

1. An ion implantation apparatus comprising a measuring device for measuring an angular distribution of an ion beam irradiated on a wafer, wherein the measuring device comprises: a slit into which the ion beam is incident; a central electrode body having a beam measuring surface arranged on a center line extending from the slit to a beam traveling direction serving as a reference of the ion beam; a plurality of side electrode bodies disposed between the slit and the central electrode body and each having a beam measuring surface disposed away from the center line in a slit width direction of the slit; and a magnet device for applying a magnetic field curved around an axis in the slit length direction to at least one beam measuring surface of the plurality of side electrode bodies; The magnet device includes: a first magnetic pole, which is arranged at a position closer to the upstream side of the beam travel direction than at least one beam measuring surface of the multiple side electrode bodies; and a second magnetic pole, which is arranged at a position closer to the downstream side of the beam travel direction than at least one beam measuring surface of the multiple side electrode bodies, and has a polarity different from that of the first magnetic pole, and applies a magnetic field in a manner such that at least a portion of the magnetic lines of force between the first magnetic pole and the second magnetic pole intersects the beam measuring surface of the corresponding side electrode body.

2. The ion implantation device according to claim 1, characterized in that: The magnet device applies a magnetic field in a manner such that magnetic lines of force emitted from at least one beam measuring surface of the multiple side electrode bodies are incident on the surface of the same side electrode body, or in a manner such that magnetic lines of force incident on at least one beam measuring surface of the multiple side electrode bodies are emitted from the surface of the same side electrode body.

3. The ion implantation device according to claim 1 or 2, characterized in that: The magnetic field strength applied to at least one beam measuring surface of the plurality of side electrode bodies is set so that the Larmor radius of secondary electrons generated on the beam measuring surface due to the incidence of the ion beam is smaller than the distance from the beam measuring surface to the center line.

4. The ion implantation device according to claim 1 or 2, characterized in that: The center of the first magnetic pole in the beam traveling direction is located closer to the upstream end of the corresponding side electrode body than the beam measuring surface of the corresponding side electrode body, and the center of the second magnetic pole in the beam traveling direction is located closer to the downstream end of the corresponding side electrode body than the beam measuring surface of the corresponding side electrode body.

5. The ion implantation device according to claim 4, characterized in that: The center of the first magnetic pole in the beam traveling direction is located downstream of the upstream end of the corresponding side electrode body, and the center of the second magnetic pole in the beam traveling direction is located upstream of the downstream end of the corresponding side electrode body.

6. The ion implantation device according to claim 1 or 2, characterized in that: The first magnetic pole and the second magnetic pole are arranged farther from the center line than the plurality of side electrode bodies in the slit width direction.

7. The ion implantation device according to claim 1 or 2, characterized in that: The plurality of side electrode bodies include a first group of side electrode bodies arranged along the beam traveling direction and a second group of side electrode bodies arranged symmetrically with respect to the first group of side electrode bodies across the center line in the slit width direction. The magnet device applies a magnetic field such that a magnetic field distribution applied to the first set of side electrode bodies and a magnetic field distribution applied to the second set of side electrode bodies are symmetrical with respect to the center line in the slit width direction.

8. The ion implantation device according to claim 1 or 2, characterized in that: The magnet device applies a magnetic field in such a way that the magnetic force lines on the center line are along the center line.

9. The ion implantation device according to claim 1 or 2, characterized in that: Each of the plurality of side electrode bodies comprises: a main body having at least a portion of the beam measuring surface; an upstream extension portion extending from the main body toward the upstream side of the beam traveling direction; and a downstream extension portion extending from the main body toward the downstream side of the beam traveling direction. A distance from each of the upstream extension portion and the downstream extension portion to the center line in the slit width direction is greater than a distance from the main body portion to the center line in the slit width direction.

10. The ion implantation device according to claim 9, characterized in that: A distance from the downstream-side extending portion to the center line in the slit width direction is smaller than a distance from the upstream-side extending portion to the center line in the slit width direction.

11. The ion implantation device according to claim 9, characterized in that: The length of each of the upstream extension portion and the downstream extension portion in the beam traveling direction is greater than the length of the main body portion in the beam traveling direction.

12. The ion implantation device according to claim 9, characterized in that: The beam measuring surface of the main body has an upper surface exposed toward the slit in the beam traveling direction and an inner side surface exposed toward the center line in the slit width direction.

13. The ion implantation device according to claim 9, characterized in that: At least a portion of the inner surface of the upstream extension portion exposed toward the center line is a beam non-irradiated surface that shields the incidence of the beam passing through the slit by a structure that is closer to the upstream side than the upstream extension portion, and is a secondary electron absorption surface on which secondary electrons generated on the beam measuring surface are incident.

14. The ion implantation apparatus according to claim 9, characterized in that: At least a portion of the inner side surface of the downstream extension portion exposed toward the center line is a beam non-irradiated surface shielded by the main body from incidence of the beam having passed through the slit, and is a secondary electron absorption surface onto which secondary electrons generated on the beam measuring surface are incident.

15. The ion implantation device according to claim 1 or 2, characterized in that: The magnet device applies a magnetic field so that the magnetic field distribution applied to the beam measuring surface of the central electrode body becomes asymmetric with respect to the center line in the slit width direction.

16. The ion implantation device according to claim 15, characterized in that: The central electrode body comprises: a base having a beam measuring surface exposed toward the slit in the beam traveling direction; and a pair of extension portions extending from both ends of the base in the slit width direction toward the upstream side of the beam traveling direction, The magnet device applies a magnetic field in a manner such that magnetic lines of force emitted from the beam measurement surface of the base are incident on one surface of the pair of extensions or in a manner such that magnetic lines of force incident on the beam measurement surface of the base are emitted from the one surface of the pair of extensions.

17. The ion implantation device according to claim 1 or 2, characterized in that: The measuring device further includes a bias power supply for applying a negative voltage to the central electrode body and the plurality of side electrode bodies with reference to the potential of the slit.

18. A measuring device for measuring the angular distribution of an ion beam, the measuring device comprising: a slit into which the ion beam is incident; a central electrode body having a beam measuring surface arranged on a center line extending from the slit to a beam traveling direction serving as a reference of the ion beam; a plurality of side electrode bodies disposed between the slit and the central electrode body, each having a beam measuring surface disposed away from the center line in a slit width direction of the slit; and a magnet device for applying a magnetic field curved around an axis in the slit length direction to at least one beam measuring surface of the plurality of side electrode bodies; The magnet device includes: a first magnetic pole, which is arranged at a position closer to the upstream side of the beam travel direction than at least one beam measuring surface of the multiple side electrode bodies; and a second magnetic pole, which is arranged at a position closer to the downstream side of the beam travel direction than at least one beam measuring surface of the multiple side electrode bodies, and has a polarity different from that of the first magnetic pole, and applies a magnetic field in a manner such that at least a portion of the magnetic lines of force between the first magnetic pole and the second magnetic pole intersects the beam measuring surface of the corresponding side electrode body.

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