Ion implantation apparatus, ion implantation method

Abstract

To provide an ion implanter or the like capable of shortening a time for which workpieces stay in a beam non-irradiation range.SOLUTION: An ion implantation method includes the steps of: (a) moving a wafer adjusted to have a first implantation angle with respect to an ion beam from a beam irradiation range in which the wafer is irradiated with the ion beam toward a beam non-irradiation range which is adjacent to at least one end of the beam irradiation range and in which the wafer is not irradiated with the ion beam; (b) starting a change of the wafer from the first implantation angle to a second implantation angle while the wafer having the first implantation angle is moved within the beam non-irradiation range to which the wafer is moved from the beam irradiation range; (c-1) reversing a movement direction of the wafer at an end of the beam non-irradiation range and moving the wafer toward the beam irradiation range; and (c-2) completing the change of the wafer from the first implantation angle to the second implantation angle while the wafer is moved within the beam non-irradiation range before the wafer is returned to the beam irradiation range.SELECTED DRAWING: Figure 18

Description

Technical Field

[0001] The present invention relates to an ion implantation apparatus and an ion implantation method.

Background Art

[0002] Patent Document 1 discloses an ion implantation apparatus that irradiates the same wafer that reciprocates with ion beams having different implantation angles a plurality of times. When the irradiation direction of the ion beam is substantially constant, the implantation angle of the ion beam with respect to the wafer is determined by, for example, a combination of the twist angle (rotation angle) and tilt angle (inclination angle) of the wafer. Since the end of the reciprocating movement range of the wafer is a beam non-irradiation range where the ion beam does not irradiate the wafer, when reversing the movement direction of the wafer at the end of the reciprocating movement range, which is also the end of the beam non-irradiation range, by changing the twist angle and / or tilt angle of the wafer, the implantation angle can be changed without exposing the wafer to the ion beam.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the ion implantation apparatus of Patent Document 1, since it is necessary to change the twist angle and / or tilt angle of the wafer when reversing the movement direction at the end of the reciprocating movement range (beam non-irradiation range) of the wafer, the time that the wafer stays in the beam non-irradiation range becomes long. Since the ion beam does not irradiate the wafer within the beam non-irradiation range, there is a risk that the efficiency of the ion implantation process will decrease as a result.

[0005] The present invention has been made in view of these circumstances, and one exemplary objective is to provide an ion implantation apparatus that can shorten the residence time in the beam-free area when changing the implantation angle of the workpiece relative to the ion beam. [Means for solving the problem]

[0006] To solve the above problems, an ion implantation apparatus according to one aspect of the present invention comprises: a support mechanism for supporting a workpiece to be irradiated with an ion beam; an implantation angle adjustment mechanism capable of adjusting the implantation angle of the workpiece supported by the support mechanism with respect to the ion beam; a drive mechanism for reciprocating the support mechanism in a direction intersecting the ion beam, wherein the reciprocating movement range includes a beam irradiation range in which at least a part of the workpiece is irradiated with the ion beam, and a beam non-irradiation range adjacent to at least one end of the beam irradiation range in which the workpiece is not irradiated with the ion beam; a processor for controlling the implantation angle adjustment mechanism and the drive mechanism; and a memory for storing a program. Based on the program, the processor performs the following steps: (a) moving a workpiece adjusted to a first injection angle by an injection angle adjustment mechanism from the beam-irradiated area to the beam-non-irradiated area by a drive mechanism; (b) following step (a), while the workpiece at the first injection angle is moving within the beam-non-irradiated area after being moved from the beam-irradiated area by the drive mechanism, the injection angle adjustment mechanism starts changing the workpiece from a first injection angle to a second injection angle different from the first injection angle; (c-1) following step (b), reversing the direction of movement of the workpiece at the edge of the beam-non-irradiated area and moving it towards the beam-irradiated area by the drive mechanism; and (c-2) following step (b), while the workpiece is moving within the beam-non-irradiated area before being moved back to the beam-irradiated area by the drive mechanism, the injection angle adjustment mechanism completes changing the workpiece from a first injection angle to a second injection angle.

[0007] In this embodiment, the change to the second implantation angle begins after the workpiece at the first implantation angle has moved from the beam-irradiated area to the beam-non-irradiated area, but before it reaches the reversal end of the movement direction in the beam-non-irradiated area (hereinafter referred to as the reversal end). The change to the second implantation angle is completed while the workpiece is moving within the beam-non-irradiated area before it returns to the beam-irradiated area. By performing the movement of the workpiece within the beam-non-irradiated area and the change in the implantation angle in parallel, the time the workpiece spends in the beam-non-irradiated area can be shortened. As a result, the time the workpiece spends in the beam-irradiated area where it is irradiated with an ion beam becomes relatively longer, thus improving the efficiency of the ion implantation process.

[0008] Another aspect of the present invention is an ion implantation method. This method comprises (a) moving a workpiece adjusted to a first implantation angle with respect to an ion beam from a beam-irradiated area where the ion beam irradiates at least a portion of the workpiece toward a beam-non-irradiated area adjacent to at least one end of the beam-irradiated area where the ion beam does not irradiate the workpiece; (b) following step (a), initiating a change from the first implantation angle of the workpiece to a second implantation angle different from the first implantation angle while the workpiece is moving within the beam-non-irradiated area after it has moved from the beam-irradiated area to the beam-non-irradiated area; (c-1) following step (b), reversing the direction of movement of the workpiece at the end of the beam-non-irradiated area and moving toward the beam-irradiated area; and (c-2) following step (b), completing the change from the first implantation angle to the second implantation angle of the workpiece while it is moving within the beam-non-irradiated area before it returns to the beam-irradiated area.

[0009] Furthermore, any combination of the above components, as well as conversions of the expression of the present invention between methods, apparatus, systems, recording media, computer programs, etc., are also valid embodiments of the present invention. [Effects of the Invention]

[0010] According to an aspect of the present invention, it is possible to shorten the residence time in the non-irradiation range of the beam when changing the injection angle of the workpiece with respect to the ion beam.

Brief Description of the Drawings

[0011] [Figure 1] It is a top view showing a schematic configuration of an ion implantation apparatus. [Figure 2] It is a side view showing a schematic configuration of an ion implantation apparatus. [Figure 3] It schematically shows an ion beam deflected from the irradiatable direction to the non-irradiatable direction by an electric field. [Figure 4] It schematically shows an ion beam deflected from the irradiatable direction to the non-irradiatable direction by a magnetic field. [Figure 5] It shows a modified example of a beam blocking mechanism. [Figure 6] It shows a modified example of a beam blocking mechanism. [Figure 7] It shows a modified example of a beam blocking mechanism. [Figure 8] It shows a modified example of a beam blocking mechanism. [Figure 9] It shows a modified example of a beam blocking mechanism. [Figure 10] It is a front view showing a schematic configuration inside the implantation processing chamber. [Figure 11] It is a top view schematically showing the inside of the implantation processing chamber in the implantation process. [Figure 12] It is a top view schematically showing the inside of the implantation processing chamber in the preparation process. [Figure 13] It is a top view schematically showing the inside of the implantation processing chamber in the calibration process. [Figure 14] It is a diagram schematically showing the implantation process with a non-zero tilt angle. [Figure 15] It schematically shows the change in the twist angle by a twist angle adjustment mechanism. [Figure 16] It schematically shows the non-zero tilt angle implantation process with different twist angles. <000**********92><000**********93>It is a functional block diagram of an ion implantation apparatus. <000**********94><000**********95>It is a timing chart schematically showing the basic operations in the ion implantation process of an ion implantation apparatus. [Figure 19] An example of realizing a beam scanning function and a beam deflection function with a single beam scanning device is schematically shown.

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. The same or equivalent components, members, and processes in the description or the drawings are denoted by the same reference numerals, and duplicate descriptions are omitted. The scales and shapes of the respective parts shown are set for convenience in order to facilitate the description, and are not to be construed restrictively unless otherwise specified. The embodiments are illustrative and do not limit the scope of the present invention in any way. All features described in the embodiments and combinations thereof are not necessarily essential to the invention.

[0013] FIG. 1 is a top view showing a schematic configuration of an ion implantation apparatus 10 according to an embodiment of the present invention, and FIG. 2 is a side view showing the schematic configuration of the ion implantation apparatus 10. The ion implantation apparatus 10 is an apparatus for performing an ion implantation process on the surface of a workpiece W. The workpiece W is, for example, a substrate such as a semiconductor wafer or a display device. In this specification, the workpiece W is also referred to as a wafer W for convenience, but it is not intended to limit the object of the ion implantation process to a specific object or substance such as a semiconductor wafer.

[0014] The ion implantation apparatus 10 can irradiate the entire surface of the wafer W to be processed with the ion beam by scanning the ion beam back and forth in one direction (hereinafter also referred to as the scanning direction, beam scanning direction, or beam movement direction) and by moving the wafer W back and forth in a direction perpendicular to the scanning direction (hereinafter also referred to as the reciprocating motion direction, reciprocating movement direction, or wafer movement direction). In this specification, the direction of propagation of the ion beam along the design beamline A (hereinafter also referred to as the beam propagation direction) is defined as the z direction, and the plane perpendicular to the z direction is defined as the xy plane. When scanning the ion beam with respect to the workpiece W, the scanning direction of the ion beam (beam movement direction) is defined as the x direction, and the z direction and the y direction perpendicular to the x direction are defined as the wafer movement direction. Thus, the reciprocating scanning of the ion beam is performed in the x direction, and the reciprocating motion of the wafer W is performed in the y direction.

[0015] The ion implantation apparatus 10 comprises an ion generator 12, a beamline apparatus 14, an implantation chamber 16, and a wafer transport apparatus 18. The ion generator 12 supplies an ion beam to the beamline apparatus 14. The beamline apparatus 14 transports the ion beam supplied from the ion generator 12 to the implantation chamber 16. The implantation chamber 16 houses the wafer W to be ion implanted, and an ion implantation process is performed by irradiating the wafer W with the ion beam supplied from the beamline apparatus 14. The wafer transport apparatus 18, acting as a transport apparatus, carries untreated wafers into the implantation chamber 16 before ion implantation and removes treated wafers from the implantation chamber 16 after ion implantation. Although not shown in the figures, the ion implantation apparatus 10 is provided with a vacuum evacuation system to provide a desired vacuum environment to the ion generator 12, beamline apparatus 14, implantation chamber 16, and wafer transport apparatus 18.

[0016] The beamline apparatus 14 comprises, in order from the upstream side of beamline A, a mass spectrometry unit 20, a beam park apparatus 24, a beam shaping unit 30, a beam scanning device 32, a beam parallelization unit 34, and an angular energy filter (AEF) 36. The upstream side of beamline A is the side closer to the ion generator 12, and the downstream side of beamline A is the side closer to the injection processing chamber 16 (or beam stopper 46).

[0017] A mass spectrometry unit 20, located downstream of the ion generator 12, selects or extracts desired ion species for use in ion implantation from the ion beam generated by the ion generator 12 through mass spectrometry. The mass spectrometry unit 20 comprises a mass spectrometry magnet 21, a mass spectrometry lens 22, and a mass spectrometry slit 23.

[0018] The mass spectrometry magnet 21 applies a magnetic field to the ion beam drawn from the ion generator 12, deflecting the ion beam into different orbits depending on the value of the ion's mass-to-charge ratio M = m / q (where m is mass and q is charge). The mass spectrometry magnet 21 can also deflect the ion beam in the x direction by applying a magnetic field in the -y direction, for example. The magnetic field strength of the mass spectrometry magnet 21 is adjusted so that ion species with a desired mass-to-charge ratio M can pass through the downstream mass spectrometry slit 23.

[0019] The mass spectrometry lens 22 is located downstream of the mass spectrometry magnet 21 (and upstream of the mass spectrometry slit 23) and adjusts the focusing / diverging force (or degree of focusing / divergence of the ion beam) on the ion beam. The mass spectrometry lens 22 adjusts the focusing position of the ion beam in the beam propagation direction (z direction) as it passes through the mass spectrometry slit 23, thereby adjusting the mass resolution M / dM of the mass spectrometry unit 20. Note that the mass spectrometry lens 22 does not necessarily have to be located in the mass spectrometry unit 20.

[0020] The mass spectrometry slit 23 is located downstream of the mass spectrometry lens 22. The mass spectrometry slit 23 has a rectangular aperture 23a with a relatively short width in the x-direction and a relatively long height in the y-direction. Since the width direction (x-direction) of the aperture 23a coincides with the beam deflection direction (x-direction) by the mass spectrometry magnet 21, the width of the aperture 23a (dimension in the x-direction) is the main factor contributing to the selection of desired ion species according to the mass-to-charge ratio M in the mass spectrometry slit 23.

[0021] The mass spectrometry slit 23 may have a variable slit width (width of the aperture 23a) to adjust the mass resolution. For example, the mass spectrometry slit 23 may be constructed with two shielding bodies that can move relative to each other in the slit width direction (x direction), and the slit width may be adjusted by changing the distance between the two shielding bodies in the slit width direction. Alternatively, the mass spectrometry slit 23 may have its slit width changed by switching between multiple slits with different slit widths.

[0022] The beam park device 24 constitutes a beam deflection device that deflects the ion beam using at least one of an electric field and a magnetic field. Specifically, the beam park device 24 can switch between an irradiable state in which the ion beam is directed in an irradiable direction that allows it to irradiate the wafer W, and an irradiable state in which the ion beam is directed in an irradiable direction that prevents it from irradiating the wafer W. In the example in Figure 2, the arrow pointing into the aperture 23a of the mass spectrometry slit 23 represents the irradiable direction, and the arrow pointing to the beam dump 26 outside the aperture 23a of the mass spectrometry slit 23 represents the irradiable direction. Here, the mass spectrometry slit 23 is a slit through which at least a portion of the ion beam directed in the irradiable direction passes, and is provided between the beam park device 24 as a beam deflection device and the wafer holding device 52 (Figure 2), which will be described later as a holding device.

[0023] When the beam park device 24 is in an un-irradiable state, it temporarily retracts the ion beam from beamline A and shields the ion beam heading towards the downstream implantation chamber 16 (or wafer W) with the beam dump 26. That is, the ion beam heading in the un-irradiable direction collides with the beam dump 26 outside the mass spectrometry slit 23 and is blocked. The beam park device 24 can be placed at any position on beamline A, but in the illustrated example, it is placed between the mass spectrometry lens 22 and the mass spectrometry slit 23. As mentioned above, a certain distance is required between the mass spectrometry lens 22 and the mass spectrometry slit 23, so placing the beam park device 24 in between allows for efficient use of space. As a result, beamline A can be shortened and the entire ion implantation apparatus 10 can be miniaturized compared to placing the beam park device 24 in another location.

[0024] The beam park device 24 shown in Figures 1 and 2 constitutes a beam deflection device of the type that deflects the ion beam using an electric field. This beam park device 24 is equipped with a pair of park electrodes 25 (25a, 25b) and a beam damper 26. The pair of park electrodes 25a and 25b face each other in the y direction across beamline A. The beam park device 24 switches the ion beam between an irradiable direction and an irradiable direction in response to the change in the electric field in the y direction caused by changing the voltage applied to the pair of park electrodes 25a and 25b.

[0025] In the example shown in Figure 2, when no voltage is applied to the pair of park electrodes 25a and 25b (i.e., when the voltage is approximately zero), the beam of the desired ion species used for ion implantation is not deflected and travels straight in the irradiable direction, passing through the aperture 23a of the mass spectrometry slit 23, resulting in an irradiable state. On the other hand, when a voltage is applied to the pair of park electrodes 25a and 25b (i.e., when the voltage is a significant non-zero value), the beam of the desired ion species used for ion implantation is deflected in the -y direction, travels in the non-irradiable direction, collides with the beam dump 26 outside the aperture 23a of the mass spectrometry slit 23, and is shielded, resulting in a non-irradiable state.

[0026] In the above example, when no voltage is applied to the pair of park electrodes 25a and 25b, the ion beam moves in the irradiable direction when it is not deflected, and when a voltage is applied to the pair of park electrodes 25a and 25b, the ion beam moves in the non-irradiable direction when it is deflected. However, it is also possible to configure the ion beam so that when it is not deflected, it moves in the non-irradiable direction, and when it is deflected, it moves in the irradiable direction. In this case, for example, a beam dump 26 can be provided at the position of the aperture 23a of the mass spectrometry slit 23 in Figure 2, and the aperture 23a of the mass spectrometry slit 23 can be provided at the position of the beam dump 26 in Figure 2. In this case, the configuration downstream of the aperture 23a is also provided on the beamline A of the (deflected) ion beam passing through the aperture 23a.

[0027] Furthermore, the ion beam traveling in the irradiable direction and the ion beam traveling in the non-irradiable direction may be deflected by different voltages applied to a pair of park electrodes 25a and 25b. For example, if the irradiable direction (the direction in which the aperture 23a of the mass spectrometry slit 23 is located) has a first deflection angle Θ1 with respect to the direction in which the ion beam is incident to the beam park device 24, and the non-irradiable direction (the direction in which the beam dump 26 is located) has a second deflection angle Θ2 that is significantly different from the first deflection angle Θ1 with respect to the direction in which the ion beam is incident to the beam park device 24, the direction in which the beam of a desired ion species travels can be switched between the irradiable direction and the non-irradiable direction by switching the voltage applied to the pair of park electrodes 25a and 25b between a first voltage V1 that realizes the first deflection angle Θ1 and a second voltage V2 (≠V1) that realizes the second deflection angle Θ2.

[0028] As described above, the opposing direction of the pair of park electrodes 25a and 25b is the y-direction, which is perpendicular to the beam deflection direction (x-direction) of the mass spectrometry magnet 21. Therefore, the deflection voltage in the y-direction applied to the pair of park electrodes 25a and 25b does not hinder the selection of desired ion species according to the mass-to-charge ratio M performed by the mass spectrometry magnet 21 along the x-direction.

[0029] In the example shown in Figure 2, the first park electrode 25a is positioned above beamline A in the direction of gravity (opposing direction of the first park electrode 25a and the second park electrode 25b), and the second park electrode 25b is positioned below beamline A in the direction of gravity. The beam dump 26, located downstream of the first park electrode 25a and the second park electrode 25b, is positioned below beamline A in the direction of gravity and below the opening 23a of the mass spectrometry slit 23 in the direction of gravity. The beam dump 26 is, for example, a wall-like portion where the opening 23a of the mass spectrometry slit 23 is not formed. Note that the beam dump 26 may be configured separately from the mass spectrometry slit 23.

[0030] Figure 3 schematically shows an ion beam IB deflected from the irradiable direction D1 (or beamline A) to the non-irradiable direction D2 by the voltage applied to a pair of park electrodes 25a and 25b. The deflection angle θ of the ion beam IB shown is the angle between the irradiable direction D1 and the non-irradiable direction D2. Here, the ion beam IB curves as it travels between the electrodes and in the vicinity of the electric field acting between the pair of park electrodes 25a and 25b, but the deflection angle θ of the ion beam IB is defined as the angle between the straight line of the irradiable direction D1, which the ion beam IB traveled in a straight line before it curved, and the straight line of the non-irradiable direction D2, which the ion beam IB traveled in a straight line after it curved. If the deflection angle θ is too small, there is a risk that a part of the ion beam IB will enter the aperture 23a of the mass spectrometry slit 23, and if the deflection angle θ is too large, the mass spectrometry slit 23 that constitutes the beam dump 26 will become larger. Based on the inventors' research, it is preferable that the deflection angle θ between the irradiable direction D1 and the non-irradiable direction D2 be between 2 degrees and 60 degrees. More preferably, the deflection angle θ is between 3 degrees and 45 degrees, and even more preferably between 5 degrees and 30 degrees.

[0031] Figure 4 schematically shows an ion beam IB deflected from the irradiable direction D1 (or beamline A) to the non-irradiable direction D2 by a magnetic field applied between a pair of magnetic poles 25c and 25d. While the beam park apparatus 24 shown in Figures 1 to 3 constitutes a beam deflection apparatus of the type that deflects the ion beam by an electric field, the modified beam park apparatus 24 in Figure 4 constitutes a beam deflection apparatus of the type that deflects the ion beam by a magnetic field.

[0032] This beampark device 24 is equipped with a pair of magnetic poles 25c and 25d facing each other in the x-direction with respect to the ion beam IB. Each magnetic pole 25c and 25d is a core of a magnetic material such as iron, and coils 25e and 25f are wound around its outer circumference. Each magnetic pole 25c and 25d and each coil 25e and 25f constitute an electromagnet that produces a change in the magnetic field in the x-direction by changing the current applied to each coil 25e and 25f. Due to the magnetic field in the x-direction between each magnetic pole 25c and 25d, the ion beam IB propagating in the z-direction is subjected to a Lorentz force in the -y-direction, and the ion beam IB can be switched between the irradiable direction D1 and the non-irradiable direction D2, as in Figure 3. In addition to the coils 25e and 25f wound around each magnetic pole 25c and 25d, coils may be wound around a yoke (not shown) that magnetically connects the pair of magnetic poles 25c and 25d.

[0033] In the example shown in Figure 4, when no magnetic field in the x-direction is applied between the pair of magnetic poles 25c and 25d, the beam of the desired ion species used for ion implantation is not deflected and travels straight in the irradiable direction, passing through the aperture 23a of the mass spectrometry slit 23, resulting in an irradiable state. On the other hand, when a magnetic field in the x-direction is applied between the pair of magnetic poles 25c and 25d, the beam of the desired ion species used for ion implantation is deflected in the -y direction, travels in the non-irradiable direction, collides with the beam dump 26 outside the aperture 23a of the mass spectrometry slit 23, and is shielded, resulting in a non-irradiable state.

[0034] In the above example, when no magnetic field is applied between the pair of magnetic poles 25c and 25d, the ion beam moves in the direction of irradiation when it is not deflected, and when a magnetic field is applied between the pair of magnetic poles 25c and 25d, the ion beam moves in the direction of non-irradiation when it is deflected. However, the ion beam may also move in the direction of non-irradiation when it is not deflected, and the ion beam may move in the direction of irradiation when it is deflected. Furthermore, the ion beam moving in the direction of irradiation and the ion beam moving in the direction of non-irradiation may be deflected by different magnetic fields applied between the pair of magnetic poles 25c and 25d.

[0035] In addition, instead of or in addition to the beam park apparatus 24 in the embodiments shown in Figures 1-3 or the modified example in Figure 4, the mass spectrometry magnet 21 in the mass spectrometry unit 20 may be used as a beam deflection device that deflects the ion beam between the irradiable direction and the non-irradiable direction using a magnetic field. As described above, the mass spectrometry magnet 21 deflects the ion beam in the x direction by applying a magnetic field in the -y direction, so that in the irradiable state, ion species having the desired mass-to-charge ratio M pass through the aperture 23a of the mass spectrometry slit 23. On the other hand, in the non-irradiable state, the magnetic field of the mass spectrometry magnet 21 in the y direction is changed to deflect the ion beam containing the desired ion species to a position in the x direction away from the aperture 23a of the mass spectrometry slit 23. In this case, the beam dump 26, which is located at a position away from the aperture 23a in the y direction in the example of Figure 2, will be located at a position away from the aperture 23a in the x direction. Furthermore, an electric field deflection type beam park device 24, as shown in the embodiments of Figures 1-3, and a magnetic field deflection type beam park device 24, as shown in the modified example in Figure 4, may be used in combination to deflect the ion beam between the irradiable direction and the non-irradiable direction.

[0036] Hereinafter, the various beam park devices 24 described above and the mass spectrometry magnets 21 in the mass spectrometry unit 20 that function as beam deflection devices will be collectively referred to as the beam deflection device 24.

[0037] In Figures 1 and 2, an injector Faraday cup 28, which also functions as a beam blocking mechanism, is provided downstream of the mass spectrometry slit 23. The injector Faraday cup 28 can be moved in and out of beamline A by the operation of the injector drive unit 29. The injector drive unit 29 moves the injector Faraday cup 28 in a direction perpendicular to the direction in which beamline A extends (z direction) (for example, the y direction). As shown by the dashed line in Figure 2, when the injector Faraday cup 28 is positioned on beamline A, the ion beam heading downstream is physically blocked, resulting in a blocked state. On the other hand, as shown by the solid line in Figure 2, when the injector Faraday cup 28 is removed from beamline A, the ion beam heading downstream is not physically blocked and passes through, resulting in an unblocked state. Thus, the injector Faraday cup 28 and the injector drive unit 29 function as a beam blocking mechanism that can switch between a blocked state in which the ion beam is physically blocked and an unblocked state in which the ion beam passes through.

[0038] The injector-Faraday cup 28 measures the beam current of the ion beam that has been mass-analyzed by the mass spectrometry unit 20. By measuring the beam current while changing the magnetic field strength of the mass spectrometry magnet 21, the injector-Faraday cup 28 can obtain the mass spectrometry spectrum of the ion beam. This mass spectrometry spectrum is used, for example, to calculate the mass resolution of the mass spectrometry unit 20.

[0039] Figures 5 to 9 show modified versions of the beam blocking mechanism. In each figure, A (e.g., Figure 5A) shows the blocking state in which the beam blocking mechanism physically blocks the ion beam IB, and in each figure, B (e.g., Figure 5B) shows the non-blocking state in which the beam blocking mechanism allows the ion beam IB to pass through.

[0040] The beam blocking mechanism in Figure 5 is a circular or plate-shaped shielding plate 28a. In the blocked state shown in Figure 5A, the shielding plate 28a is positioned on beamline A, physically blocking the ion beam IB. In the unblocked state shown in Figure 5B, the shielding plate 28a is rotated from the blocked state around a rotation axis perpendicular to the direction in which beamline A extends (z-direction) (for example, the x-direction), as shown by the arrow in the figure, and moves away from beamline A, allowing the ion beam IB to pass through.

[0041] The beam blocking mechanism in Figure 6 is a circular or plate-shaped shielding plate 28b. In the blocked state shown in Figure 6A, the shielding plate 28b is positioned on beamline A, physically blocking the ion beam IB. In the unblocked state shown in Figure 6B, the shielding plate 28b is moved from the blocked state in a direction perpendicular to the direction in which beamline A extends (z direction) (for example, the y direction), as shown by the arrow, and is removed from beamline A, allowing the ion beam IB to pass through.

[0042] The beam blocking mechanism in Figure 7 is a disc-shaped shielding plate 28c, with at least one window 28d or hole formed on its outer circumference through which the ion beam IB can pass. In the blocked state shown in Figure 7A, the window 28d is off-center from the beamline A, so the portion of the shielding plate 28c other than the window 28d physically blocks the ion beam IB. In the unblocked state shown in Figure 7B, the window 28d of the shielding plate 28c, which has been rotated from the blocked state around a rotation axis parallel to the direction in which the beamline A extends (z-direction) as shown by the arrow, is positioned on the beamline A, allowing the ion beam IB to pass through the window 28d.

[0043] The beam blocking mechanism in Figure 8 is a plate-shaped shielding plate 28e that can rotate around a rotation axis 28f perpendicular to the direction in which beamline A extends (z-direction) (for example, the x-direction). In the blocked state shown in Figure 8A, the shielding plate 28e is positioned on beamline A, physically blocking the ion beam IB. In the unblocked state shown in Figure 8B, the shielding plate 28e, rotated around the rotation axis 28f as shown by the arrows in the figure, moves away from beamline A, allowing the ion beam IB to pass through.

[0044] The beam blocking mechanism in Figure 9 is a block-shaped shielding body 28g that is rotatable around a rotation axis perpendicular to the direction in which the beamline A extends (z-direction), with a passage 28h through which the ion beam IB can pass. In the blocked state shown in Figure 9A, the passage 28h intersects or is perpendicular to the beamline A, so the portion of the shielding body 28g other than the passage 28h physically blocks the ion beam IB. In the unblocked state shown in Figure 9B, the passage 28h of the shielding body 28g, which has been rotated from the blocked state as shown by the arrow, is positioned approximately parallel to the beamline A, so the ion beam IB can pass through the passage 28h.

[0045] In the following, the beam blocking mechanisms shown in Figures 5 to 9 and the injector Faraday cup 28 shown in Figures 1 and 2 will be collectively referred to as the beam blocking mechanism 28.

[0046] In Figures 1 and 2, the beam shaping unit 30 is equipped with a focusing / diverging device such as a focusing / diverging quadrupole lens (Q lens) to shape the ion beam that has passed through the mass spectrometry unit 20 into a desired cross-sectional shape. For example, a beam shaping unit 30 composed of an electric field type triple quadrupole lens (also called a triplet Q lens) has three quadrupole lenses 30a, 30b, and 30c. By using the three lens devices 30a to 30c, the beam shaping unit 30 can independently adjust the focusing or divergence of the ion beam in the x and y directions. The beam shaping unit 30 may include a magnetic field type lens device, or it may include a lens device that shapes the ion beam using both electric and magnetic fields.

[0047] The beam scanning device 32 reciprocates a predetermined scanning angle range in the x-direction with an ion beam (shaped by the beam shaping unit 30) irradiated onto the wafer W by at least one of an electric field and a magnetic field. As will be described later, the beam scanning device 32 can also be used as a beam deflection device to deflect the ion beam between the irradiable direction and the non-irradiable direction, in place of or in addition to the beam park device 24. The beam scanning device 32 is equipped with a pair of scanning electrodes facing the beam scanning direction (x-direction). The pair of scanning electrodes is connected to a variable voltage power supply (not shown), and by periodically changing the voltage applied between the pair of scanning electrodes, the electric field between the electrodes is changed, deflecting the ion beam to various angles in the zx plane. As a result, the ion beam is scanned over the entire scanning range in the x-direction. In Figure 1, the scanning direction and scanning range of the ion beam are illustrated by arrow X, and multiple trajectories of the ion beam within the scanning range are illustrated by dashed lines.

[0048] The beam parallelization unit 34 adjusts the direction of the ion beam scanned by the beam scanning device 32 to be approximately parallel to the trajectory of the design beamline A. The beam parallelization unit 34 is equipped with multiple arc-shaped parallelization lens electrodes, each having an ion beam passage slit in the center in the y-direction. The parallelization lens electrodes are connected to a high-voltage power supply (not shown), and the applied voltage creates an electric field that acts on the ion beam to align the direction of the ion beam to be approximately parallel to beamline A. The beam parallelization unit 34 may be replaced with other types of beam parallelization devices, such as magnetic devices that utilize a magnetic field. Furthermore, an AD (Accel / Decel) column (not shown) for accelerating or decelerating the ion beam may be provided downstream of the beam parallelization unit 34.

[0049] The angle energy filter (AEF) 36 analyzes the energy of the ion beam and deflects ions with the required energy downward (-y direction) to guide them to the injection chamber 16. The angle energy filter 36 is equipped with a pair of AEF electrodes for electric field deflection connected to a high-voltage power supply (not shown). In Figure 2, a positive voltage is applied to the upper (+y side) AEF electrode and a negative voltage is applied to the lower (-y side) AEF electrode to deflect the positively charged ion beam downward (in the case of a negatively charged ion beam, a negative voltage is applied to the upper AEF electrode and a positive voltage is applied to the lower AEF electrode). The angle energy filter 36 may be composed of a magnetic device for magnetic field deflection, or it may be composed of a combination of a pair of AEF electrodes for electric field deflection and a magnetic device for magnetic field deflection.

[0050] As described above, the beamline apparatus 14 supplies an ion beam to be irradiated onto the wafer W, which is the workpiece, to the injection chamber 16. The injection chamber 16 comprises, in order from the upstream side of the beamline A, an energy slit 38, a plasma shower apparatus 40, side cups 42 (42R, 42L), a profiler cup 44, and a beam stopper 46. As shown in Figure 2, the injection chamber 16 includes a platen drive device 50 that holds one or more wafers W.

[0051] The energy slit 38 is located downstream of the angular energy filter 36 and analyzes the energy of the ion beam incident on the wafer W together with the angular energy filter 36. The energy slit 38 is an energy-defining slit (EDS), which is a horizontally elongated slit in the beam scanning direction (x-direction). The energy slit 38 allows ion beams with energy within a desired value or range to pass towards the wafer W, while shielding other ion beams.

[0052] The plasma shower apparatus 40 is positioned downstream of the energy slit 38. The plasma shower apparatus 40 supplies low-energy electrons to the ion beam and / or the surface of the wafer W (the wafer surface to be processed) in accordance with the beam current of the ion beam, thereby suppressing the accumulation of positive charge on the wafer surface to be processed (so-called charge-up) that occurs during ion implantation. The plasma shower apparatus 40 includes, for example, a shower tube through which the ion beam passes and a plasma generator that supplies electrons into the shower tube.

[0053] The side cups 42 (42R, 42L) measure the beam current of the ion beam during the ion implantation process on the wafer W. As shown in Figure 1, the side cups 42R and 42L are positioned offset to the left and right (x-direction) from the wafer W, which is located on beamline A, so as not to obstruct the ion beam directed toward the wafer W during ion implantation. Since the ion beam is scanned in the x-direction beyond the range where the wafer W is located, a portion of the scanned beam is incident on the side cups 42R and 42L even during ion implantation. In this way, the beam current during the ion implantation process is measured by the side cups 42R and 42L. Since the ion beam incident on the side cups 42R and 42L during ion implantation is not irradiated onto the wafer W as the workpiece, the side cups 42R and 42L constitute a second beam current measuring instrument (the first beam current measuring instrument will be described later) that measures the beam current of the ion beam directed in a direction that cannot irradiate the wafer W. Furthermore, a beam current measuring device such as a Faraday cup may be installed on the beam dump 26, where the ion beam heading in the direction of non-irradiation collides, to serve as a second beam current measuring device.

[0054] The profiler cup 44 measures the beam current on the wafer surface being processed. The profiler cup 44 is movable in the x-direction by the operation of the drive unit 45, and is moved out of the implantation region where the wafer W is located during ion implantation, and is inserted into the implantation region when the wafer W is not in the implantation region. The profiler cup 44, driven in the x-direction, can measure the beam current over the entire beam scanning range in the x-direction. The profiler cup 44 may be equipped with multiple Faraday cups arranged in the x-direction so that the beam current at multiple positions in the beam scanning direction (x-direction) can be measured simultaneously. Since the ion beam incident on the profiler cup 44 is incident on the implantation region where the wafer W, as the workpiece, is located during ion implantation, the profiler cup 44 constitutes a first beam current measuring instrument that measures the beam current of the ion beam directed in the direction that can irradiate the wafer W. Alternatively, a beam current measuring instrument such as a Faraday cup may be provided on the beam stopper 46 into which the ion beam directed in the direction that can irradiate collides, and this can also be used as the first beam current measuring instrument.

[0055] The profiler cup 44 comprises a first profiler cup 44a and a second profiler cup 44b. The first profiler cup 44a is a first Faraday cup for normal measurement used in the preparation step before the injection step. The second profiler cup 44b is a second Faraday cup for calibration used in the calibration step. A shielding member 43 is provided in front of the second profiler cup 44b to prevent the ion beam from entering the second profiler cup 44b during the injection step and preparation step. Note that the shielding member 43 does not have to be a dedicated member for blocking the incidence of the ion beam to the second profiler cup 44b, and may be part or all of any structure provided in the injection processing chamber 16.

[0056] The second profiler cup 44b may have higher measurement accuracy than the first profiler cup 44a. For example, the second profiler cup 44b may have components that are manufactured with higher precision than the first profiler cup 44a, thereby reducing the tolerance of the aperture size into which the ion beam being measured enters. Furthermore, the second profiler cup 44b may experience a slower decrease in measurement accuracy with use compared to the first profiler cup 44a. For example, the second profiler cup 44b may be composed of components that are more wear-resistant than those of the first profiler cup 44a.

[0057] The first profiler cup 44a and the second profiler cup 44b are independently drivable by the drive unit 45. The first profiler cup 44a is movable in the x-direction along the first drive shaft 45a of the drive unit 45. The second profiler cup 44b is movable in the x-direction along the second drive shaft 45b of the drive unit 45. The directions of movement of the first profiler cup 44a and the second profiler cup 44b are substantially parallel to each other.

[0058] At least one of the side cup 42 and profiler cup 44 may be equipped with a single Faraday cup for measuring the beam current, or an angle measuring instrument for measuring the angle information of the ion beam. The angle measuring instrument may, for example, include a slit and a plurality of current detection units positioned away from the slit in the beam propagation direction (z direction). This angle measuring instrument can measure the angle component or angle distribution of the beam in the slit width direction by measuring the ion beam that has passed through the slit with a plurality of current detection units arranged in the slit width direction. At least one of the side cup 42 and profiler cup 44 may be equipped with a first angle measuring instrument capable of measuring angle information in the x direction and / or a second angle measuring instrument capable of measuring angle information in the y direction.

[0059] The platen drive unit 50 includes a wafer holding device 52, a reciprocating motion mechanism 54, a twist angle adjustment mechanism 56, and a tilt angle adjustment mechanism 58.

[0060] The wafer holding device 52 for holding the wafer W to be irradiated with an ion beam constitutes a support mechanism for supporting the wafer W and includes an electrostatic chuck as an electrostatic holding mechanism for holding the supported wafer W by electrostatic attraction. The wafer holding device 52 may also include a temperature control device for heating or cooling the wafer W to be ion implanted. The temperature control device may be a heating device that heats the wafer W to a temperature 20°C or more, 50°C or more, or 100°C or more higher than room temperature, or a cooling device that cools the wafer W to a temperature 20°C or more, 50°C or more, or 100°C or more lower than room temperature. The temperature of the wafer W affects the concentration distribution of ions implanted in the wafer W (implantation profile) and the crystal defects (implantation damage) formed in the wafer W by ion implantation. The process of irradiating a wafer W at a temperature higher than room temperature with an ion beam is also called high-temperature implantation. The process of irradiating a wafer W at a temperature lower than room temperature with an ion beam is also called low-temperature implantation.

[0061] The reciprocating motion mechanism 54 is a drive mechanism that moves the wafer holding device 52, including the support mechanism, back and forth in a direction intersecting the ion beam. The reciprocating motion mechanism 54 moves the wafer holding device 52, including the support mechanism, back and forth in a reciprocating motion direction (y direction) perpendicular to the beam scanning direction (x direction), thereby causing the wafer W held by the wafer holding device 52 to reciprocate in the y direction. In Figure 2, the direction and range of the reciprocating motion of the wafer W are illustrated by the arrow Y.

[0062] The twist angle adjustment mechanism 56, which constitutes the injection angle adjustment mechanism, is a mechanism for adjusting the rotation angle of the wafer W. By rotating the wafer W around a normal perpendicular to the wafer surface at the center of the wafer surface to be processed as the axis of rotation, the twist angle between the alignment marks provided on the outer circumference of the wafer W and the reference position is adjusted. Here, the alignment marks of the wafer W are, for example, notches or orientation flats provided on the outer circumference of the wafer W, and serve as a reference for the angular position in the crystal direction and circumferential direction of the wafer W. The twist angle adjustment mechanism 56 is provided between the wafer holding device 52 and the reciprocating motion mechanism 54, and is reciprocated together with the wafer holding device 52 by the reciprocating motion mechanism 54.

[0063] The tilt angle adjustment mechanism 58, which constitutes the injection angle adjustment mechanism, is a mechanism for adjusting the inclination of the wafer W, and adjusts the tilt angle between the direction of propagation of the ion beam toward the wafer surface and the normal to the wafer surface. In the example in Figure 2, the tilt angle is the rotation angle of the wafer W with the x-axis as the central axis of rotation, and is adjusted by the tilt angle adjustment mechanism 58. The tilt angle adjustment mechanism 58 is provided between the reciprocating motion mechanism 54 and the inner wall of the injection processing chamber 16, and the tilt angle of the wafer W is adjusted by rotating the entire platen drive unit 50, including the reciprocating motion mechanism 54, in the R direction (Figure 2).

[0064] The platen drive unit 50 holds the wafer W so that it can move between the ion implantation position where an ion beam is irradiated onto the wafer W and the transport position where the wafer W is loaded or unloaded between the wafer transport device 18. In other words, the platen drive unit 50 is a moving device that moves the wafer holder 52 between the ion implantation position where an ion beam is irradiated onto the wafer W supported by the wafer holder 52 and the transport position where the wafer transport device 18 can transport the wafer W between the wafer holder 52 and the wafer holder 52. Figure 2 shows the wafer W and the wafer holder 52 in the ion implantation position, with the wafer holder 52 holding the wafer W so that it intersects with the beamline A. The transport position of the wafer W corresponds to the position of the wafer holder 52 when the transport mechanism or transport robot provided in the wafer transport device 18 loads or unloads the wafer W through the transport opening 48.

[0065] The beam stopper 46 is located at the downstream end of beamline A and is attached, for example, to the inner wall of the injection processing chamber 16. The ion beam is incident on the beam stopper 46 when there is no wafer W and profiler cup 44 on beamline A. The beam stopper 46 is located near the transport port 48 that connects the injection processing chamber 16 and the wafer transport device 18, and in the example of Figure 2, it is located vertically below (-y direction) the transport port 48.

[0066] The beam stopper 46 is provided with a plurality of tuning cups 47 (47a, 47b, 47c, 47d). Each tuning cup 47 is a Faraday cup that measures the beam current of a portion of the ion beam incident on the beam stopper 46. The plurality of tuning cups 47 are spaced apart along the x-direction. Each tuning cup 47 is used, for example, to easily measure the beam current at the ion implantation site without using the profiler cup 44. These tuning cups 47 and / or the aforementioned side cups 42 constitute a beam current measuring instrument for dose control, which measures the beam current of the portion of the ion beam that is not irradiated to the wafer W when a portion of the ion beam is irradiated to the wafer W.

[0067] The ion implanter 10 further includes a control device 60 that controls its overall operation. The control device 60 is realized through the cooperation of hardware resources such as the central processing unit, memory, input devices, output devices, and peripheral devices connected to the computer, and software that runs using them. Regardless of the type or location of the computer, each function of the control device 60 may be realized using the hardware resources of a single computer, or it may be realized by combining hardware resources distributed across multiple computers. Details of the control device 60 will be described later.

[0068] Figure 10 is a front view (from the -z direction) of the surface WS of the wafer W to be irradiated with ion beam B, and shows the schematic configuration of the implantation chamber 16. The ion beam B is scanned back and forth in the x direction by the beam scanning device 32, as indicated by the arrow X, and constitutes a scan beam SB that sequentially irradiates the irradiation range 66 extending in the x direction. Here, the ion implantation positions 70, where the scan beam SB is incident on the surface WS of the wafer W to be irradiated and ions are implanted during the implantation process, are shown by thin solid lines.

[0069] The ion beam B is scanned back and forth across the injection range 62 where the wafer W is located, and the irradiation range 66 which includes the monitoring ranges 64R and 64L outside the injection range 62. The left and right side cups 42R and 42L are positioned in the left and right monitoring ranges 64R and 64L. The left and right side cups 42R and 42L can measure the ion beam B that is overscanned into the monitoring ranges 64R and 64L during the injection process. The x-direction range of the ion implantation position 70 coincides with the injection range 62. The y-direction range of the ion implantation position 70 coincides with the y-direction irradiation range of the ion beam B or scan beam SB. The z-direction position of the ion implantation position 70 coincides with the z-direction position of the surface WS of the wafer W to be processed.

[0070] The aforementioned profiler cup 44 is retracted in the non-irradiated area 68 (68R, 68L) outside the irradiation area 66 during the injection process. In the illustrated example where the drive unit 45 is located on the right side, the first profiler cup 44a and the second profiler cup 44b are retracted in the non-irradiated area 68R on the right side during the injection process. If the drive unit 45 is located on the left side, the first profiler cup 44a and the second profiler cup 44b may be retracted in the non-irradiated area 68L on the left side during the injection process.

[0071] The aforementioned shielding member 43 is also provided in the non-irradiated area 68R on the right side and is positioned to overlap with the second profiler cup 44b in the beam propagation direction (z direction). In other words, the range of the shielding member 43 in directions perpendicular to the beam propagation direction (x and y directions) at least partially overlaps with the range of the second profiler cup 44b in directions perpendicular to the beam propagation direction. The shielding member 43 shields the ion beam B directed toward the second profiler cup 44b, except during the calibration process. Because the shielding member 43 prevents the ion beam B from entering the second profiler cup 44b, except during the calibration process, wear and contamination of the second profiler cup 44b by the ion beam B can be prevented.

[0072] The wafers W (W1, W1', W2, W2') are driven to reciprocate in the y-direction by the reciprocating motion mechanism 54 of the platen drive unit 50, as indicated by the arrow Y, and sequentially move within a reciprocating range 69 extending in the y-direction. Here, the reciprocating range 69 is, for example, the range in the y-direction through which the centers (O1, O1', O2, O2') of the processing surface WS of the wafer W pass. The y-direction position of the upper end of the reciprocating range 69 corresponds to the y-direction position of the center O1 of wafer W1 when it has moved to the upper inversion end, and the y-direction position of the lower end of the reciprocating range 69 corresponds to the y-direction position of the center O2 of wafer W2 when it has moved to the lower inversion end.

[0073] The reciprocating movement range 69 includes a beam irradiation range 65 in which the ion beam B is irradiated to at least a portion of the surface WS of the wafer W, and a beam non-irradiation range 67 (67U, 67D) adjacent to at least one end of the beam irradiation range 65 in which the surface WS of the wafer W is not irradiated with the ion beam B. In the example of Figure 10, the beam non-irradiation range 67 includes a first beam non-irradiation range 67U adjacent to the upper end of the beam irradiation range 65 and a second beam non-irradiation range 67D adjacent to the lower end of the beam irradiation range 65.

[0074] Here, the upper end of the first beam non-irradiation area 67U coincides with the upper inversion end of the reciprocating movement range 69, and the lower end of the first beam non-irradiation area 67U (upper end of the beam irradiation area 65) corresponds to the y-direction position of the center O1' of the processed surface WS when, for example, the lower end of the wafer W1' moves upward away from the ion implantation position 70. Also, the lower end of the second beam non-irradiation area 67D coincides with the lower inversion end of the reciprocating movement range 69, and the upper end of the second beam non-irradiation area 67D (lower end of the beam irradiation area 65) corresponds to the y-direction position of the center O2' of the processed surface WS when, for example, the lower end of the wafer W2' moves downward away from the ion implantation position 70.

[0075] Next, the implantation process, preparation process, and calibration process of the ion implantation apparatus 10, which are performed under the control of the control device 60, will be described.

[0076] Figure 11 is a schematic top view showing the inside of the implantation chamber 16 during the implantation process. During the implantation process, the wafer W is placed in the implantation area 62, and the profiler cup 44 is placed in the non-irradiated area 68. The first profiler cup 44a is placed in the first retraction position 71, indicated by a dashed line, and the second profiler cup 44b is placed in the second retraction position 72, also indicated by a dashed line. The first retraction position 71 and the second retraction position 72 are adjacent in the x-direction within the right-hand non-irradiated area 68R. The first retraction position 71 is located to the left of the second retraction position 72, closer to the ion implantation position 70. The shielding member 43 is positioned to block the entrance of the second profiler cup 44b, which is located in the second retraction position 72.

[0077] In the injection process, the beam current can be continuously measured by the side cups 42R and 42L. On the other hand, the profiler cup 44 and tuning cup 47 in the injection process can only intermittently measure the beam current. Therefore, in the injection process, the dose of ions injected into the processing surface WS of the wafer W is controlled based on the beam current value measured by the side cups 42R and 42L. If the beam current value measured by the side cups 42R and 42L changes during the injection process, the reciprocating motion mechanism 54 changes the speed of the reciprocating motion of the wafer W in the y-direction, thereby adjusting the dose distribution on the processing surface WS of the wafer W. For example, if a uniform dose distribution is to be achieved within the processing surface WS, the wafer W is reciprocated at a speed proportional to the beam current value monitored by the side cups 42R and 42L. Specifically, if the monitored beam current value increases, the reciprocating motion of the wafer W is increased, and if the monitored beam current value decreases, the reciprocating motion of the wafer W is decreased. This prevents variations in dose within the treated surface WS caused by fluctuations in the beam current of the scan beam SB. If the beam current value measured by the side cups 42R and 42L deviates from a predetermined current value by, for example, ±10% or more, the ion implantation device 10 may be stopped as an abnormal value.

[0078] During the injection process, the control device 60 acquires beam current values ​​measured by the side cups 42R and 42L and controls the operation of the platen drive device 50 based on these values. For example, the control device 60 generates a speed command for the platen drive device 50 so that the wafer W reciprocates in the y-direction at a speed proportional to the beam current values ​​acquired from the side cups 42R and 42L.

[0079] Figure 12 is a schematic top view showing the inside of the injection chamber 16 during the preparation step. In the preparation step, which is performed before the injection step, the beam current of the scan beam SB is measured over the injection range 62 and the monitoring ranges 64R, 64L (i.e., the entire irradiation range 66). The beam current in the injection range 62 is measured by the first profiler cup 44a and / or tuning cup 47. The beam current in the monitoring ranges 64R, 64L is measured by the side cups 42R, 42L, as in the injection step.

[0080] In the preparation step, the first profiler cup 44a moves in the x-direction from the first retraction position 71 to one or more first measurement positions 76. Each first measurement position 76 is located on a plane (hereinafter also referred to as the measurement surface MS) that coincides with the ion implantation position 70 (or implantation range 62) in the beam propagation direction (z-direction) and is aligned with the surface WS being processed in the implantation step. Therefore, the first profiler cup 44a can measure the beam current at the first measurement positions 76 included in the ion implantation position 70 where ions are implanted into the wafer W in the implantation step. The first profiler cup 44a may also obtain the beam current distribution in the x-direction at the ion implantation position 70 (or measurement surface MS) by measuring the beam current while moving between multiple first measurement positions 76 along the x-direction.

[0081] The multiple tuning cups 47 overlap with the ion implantation position 70 (or implantation range 62) in the beam propagation direction (z direction), similar to the first measurement position 76, but are located downstream (+z direction) from the ion implantation position 70 (or measurement surface MS). Since the multiple tuning cups 47 do not need to be moved between the retraction position and the measurement position like the first profiler cup 44a, the beam current in the implantation range 62 can be measured more simply than with the first profiler cup 44a.

[0082] In the preparation process, the control device 60 acquires beam current values ​​measured by various Faraday cups in the implantation chamber 16, specifically the side cups 42R and 42L, the first profiler cup 44a, and multiple tuning cups 47. The control device 60 stores the ratio between each beam current value acquired from each Faraday cup and calculates the desired beam current value in the implantation range 62 (ion implantation position 70 or surface to be treated WS) based on the beam current values ​​in the monitor ranges 64R and 64L measured by the side cups 42R and 42L during the implantation process. Normally, the ratio between each beam current value measured in each Faraday cup depends on the configuration and settings of the optical system of the beamline device 14 and remains approximately constant even if the beam current of the ion beam B drawn from the ion generator 12 fluctuates somewhat. In other words, once the configuration and settings of the optical system of the beamline device 14 are determined in the preparation process, the ratio between each beam current value will hardly change in the subsequent implantation process. Therefore, based on the ratio between each beam current value stored in the preparation step and the beam current value measured by the side cups 42R and 42L in the implantation step, the beam current value at the ion implantation position 70 (implantation range 62 or surface WS to be processed) where ions are implanted into the wafer W in the implantation step can be calculated.

[0083] Note that the second profiler cup 44b is not used in the implantation process shown in Figure 11 and the preparation process shown in Figure 12. Throughout the preparation and implantation processes, the second profiler cup 44b remains in the second retraction position 72, where the scan beam SB is blocked by the shielding member 43. The second profiler cup 44b is used in the calibration process to calibrate the measured beam current of the first profiler cup 44a. The calibration process is performed when an unused ion implanter 10 is put into operation, or during maintenance such as cleaning or replacing the first profiler cup 44a.

[0084] Figure 13 is a schematic top view showing the inside of the implantation chamber 16 during the calibration process. During the calibration process, the second profiler cup 44b moves in the x-direction from the second retraction position 72 to one or more second measurement positions 77. Each second measurement position 77, like each first measurement position 76, overlaps with the ion implantation position 70 (or implantation range 62) in the beam propagation direction (z-direction) and lies on a plane (measurement surface MS) that coincides with the surface being treated WS during the implantation process. Each second measurement position 77 at least partially coincides with each first measurement position 76. The second profiler cup 44b can measure the beam current at the same position as the surface being treated WS during the implantation process and can measure the beam current at the same position as the first profiler cup 44a during the preparation process. The second profiler cup 44b may obtain the beam current distribution in the x-direction at the ion implantation position 70 (or measurement surface MS) by measuring the beam current while moving between multiple second measurement positions 77 along the x-direction.

[0085] In the calibration process, the first profiler cup 44a may be placed in a third retraction position 73, which is different from the first retraction position 71. In the illustrated example, the third retraction position 73 is located within the left non-irradiated area 68L. In this case, the third retraction position 73 is on the opposite side of the injection area 62 from the first retraction position 71 and the second retraction position 72. By retracting the first profiler cup 44a to the third retraction position 73, the second profiler cup 44b will not interfere with the first profiler cup 44a when it moves from the second retraction position 72 to the second measurement position 77.

[0086] In the calibration process, the first profiler cup 44a and the second profiler cup 44b may be driven separately, independently, or simultaneously. In the former case of independent drive, the first profiler cup 44a is first moved to at least one of the first measurement positions 76 to measure the beam current value at the ion implantation position 70. Subsequently, the second profiler cup 44b is moved to at least one of the second measurement positions 77 to measure the beam current value at the ion implantation position 70. In the case of simultaneous drive, the first profiler cup 44a moves in the x-direction from the first retraction position 71 toward the third retraction position 73, measuring the beam current value at one or more first measurement positions 76. Simultaneously, the second profiler cup 44b moves from the second retraction position 72 toward at least one of the second measurement positions 77 to measure the beam current value. By operating the profiler cup 44 as described above, the scan beam SB can be measured under the same conditions at the same measurement position at the ion implantation position 70 using the first profiler cup 44a and the second profiler cup 44b.

[0087] The control device 60 determines calibration parameters for calibrating the measurement value of the first profiler cup 44a based on the beam current values ​​measured by the first profiler cup 44a and the second profiler cup 44b. If the first beam current measurement value obtained by the first profiler cup 44a in the calibration process is I1, and the second beam current measurement value obtained by the second profiler cup 44b in the calibration process is I2, then the calibration parameter k is expressed as the ratio I2 / I1 of the first beam current measurement value I1 and the second beam current measurement value I2 (k=I2 / I1). Using the calibration parameter k, a calibrated beam current value I2 based on the second profiler cup 44b can be calculated using I2=k×I1, based on the beam current measurement value I1 obtained by the first profiler cup 44a in the preparation process. In the injection process, the dose of ions on the processing surface WS of the wafer W is controlled based on the beam current value k×I1 calibrated by the calibration parameter k.

[0088] Next, the implantation angle adjustment mechanism, which is composed of a twist angle adjustment mechanism 56 and a tilt angle adjustment mechanism 58, will be described. This implantation angle adjustment mechanism adjusts the implantation angle of the wafer W supported by the wafer holding device 52 relative to the ion beam. In this embodiment, multiple ion implantation processes with different implantation conditions (implantation angles) are performed continuously on the same wafer W. Below, an example is described in which the implantation angle adjustment mechanism adjusts the implantation angle in four ways, and four ion implantation processes at each of these implantation angles are performed continuously on the same wafer W. Each implantation angle is determined by a set of a constant tilt angle θ (not 0 degrees) set by the tilt angle adjustment mechanism 58 and four different twist angles φ (for example, 0 degrees, 90 degrees, 180 degrees, 270 degrees) set by the twist angle adjustment mechanism 56. In each ion implantation process with a different implantation angle, the dose distribution within the processed surface WS of the wafer W may be set to a desired non-uniform shape, and the ion implantation conditions may be set so that the current density distribution of the ion beam irradiated to each region within the processed surface WS changes.

[0089] Figure 14 schematically shows an implantation process with a non-zero tilt angle θ. Here, a wafer W with a gate 80, drain region 83, and source region 84 formed on the surface WS to be processed is tilted with respect to the ion beam B at a tilt angle θ, and the ion beam B irradiated to the lower part of the gate 80 forms a halo implantation region 85. The tilt angle θ of the wafer W is set to several degrees or more, preferably 10 degrees or more, so that the ion beam B is effectively irradiated to the lower part of the gate 80. Note that such a "non-zero tilt angle implantation process" may be performed to form any ion implantation region different from the halo implantation region.

[0090] Figures 15(a) to (d) schematically show the change in the twist angle φ due to the twist angle adjustment mechanism 56. The twist angle φ is the rotation angle of the wafer W with respect to the normal (a straight line perpendicular to the plane of the paper in Figure 15) passing through the center of the surface of the wafer W that is being processed. The twist angle φ corresponds to, for example, the rotation position (notch position) of the alignment mark 88 provided on the outer circumference of the wafer W. If the twist angle φ when the alignment mark 88 is at the bottom end of the wafer W in Figure 15(a) is φ0, then the twist angle φ when the alignment mark 88 is at the left end of the wafer W in Figure 15(b) is φ0 + 90 degrees, the twist angle φ when the alignment mark 88 is at the top end of the wafer W in Figure 15(c) is φ0 + 180 degrees, and the twist angle φ when the alignment mark 88 is at the right end of the wafer W in Figure 15(d) is φ0 + 270 degrees. In Figures 15(a) to (d), a gate 81 extending in a first direction and a gate 82 extending in a second direction perpendicular to the first direction are formed on the surface of the wafer W to be processed. The wafer W is sequentially switched to four different twist angles φ0, φ0+90 degrees, φ0+180 degrees, and φ0+270 degrees by a twist angle adjustment mechanism 56, and the ion implantation process is performed continuously on the same wafer W four times at each of these twist angles φ.

[0091] In the following, when the twist angle adjustment mechanism 56 switches the twist angle φ of the wafer W, the twist angle φ before switching will be collectively referred to as the first twist angle φ1, and the twist angle φ after switching will be collectively referred to as the second twist angle φ2. Also, the injection angle due to the first twist angle φ1 (and a predetermined tilt angle θ0) will be collectively referred to as the first injection angle, and the injection angle due to the second twist angle φ2 (and a predetermined tilt angle θ0) will be collectively referred to as the second injection angle. It is preferable that the difference between the first twist angle φ1 and the second twist angle φ2 be greater than 0 degrees and 180 degrees or less. In the example in Figure 15, when the twist angle φ is switched sequentially as in (a)→(b)→(c)→(d), the difference between the first twist angle φ1 and the second twist angle φ2 is constant at 90 degrees. Thus, when applying N different twist angles φ to the same wafer W (where N is a natural number greater than or equal to 2, and N=4 in Figure 15), it is preferable that the difference between the first twist angle φ1 and the second twist angle φ2 is equal for all N applications (constantly 90 degrees in Figure 15). In this case, the difference between the first twist angle φ1 and the second twist angle φ2 is the angle obtained by dividing 360 degrees by N (360 degrees ÷ 4 = 90 degrees in Figure 15). Furthermore, it is preferable that the number of twist angles φ applied, N, is an even number between 2 and 32.

[0092] Figures 16(a) to (d) schematically show a non-zero tilt angle injection process with different twist angles φ, as shown in Figures 15(a) to (d). By performing the injection process four times while switching the twist angle φ as shown in Figures 15(a) to (d) with the tilt angle θ of the wafer W held at a non-zero θ0, halo injection regions 85a to 85d can be formed directly beneath both gates 81 and 82, which have different extension directions.

[0093] In Figure 16(a), the extension direction (first direction) of gate 81 is set to a twist angle φ0 such that it is in the x-direction, forming a first halo injection region 85a in one adjacent region of gate 81 (the lower left region of gate 81 in Figure 16(a)). In Figure 16(b), the extension direction (second direction) of gate 82 is switched to a twist angle φ0+90 degrees such that it is in the x-direction, forming a second halo injection region 85b in one adjacent region of gate 82 (the lower left region of gate 82 in Figure 16(b)). In Figure 16(c), the extension direction (first direction) of gate 81 is switched to a twist angle φ0+180 degrees such that it is in the x-direction opposite to that in Figure 16(a), forming a third halo injection region 85c in the other adjacent region of gate 81 (the lower left region of gate 81 in Figure 16(c) and the upper right region of gate 81 in Figure 16(a)). In Figure 16(d), the extension direction (second direction) of gate 82 is switched to a twist angle of φ0 + 270 degrees, which is the x-direction opposite to that in Figure 16(b). As a result, a fourth halo injection region 85d is formed in the other adjacent region of gate 82 (the lower left region of gate 82 in Figure 16(d), and the upper right region of gate 82 in Figure 16(b)).

[0094] As described above, by performing the non-zero tilt angle injection process multiple times while changing the twist angle φ, halo injection regions can be formed in locations corresponding to the drain and source regions on both sides of the gate that extend in different directions.

[0095] In Figures 14 to 16, the injection angle of the wafer W was switched by a combination of the tilt angle θ set by the tilt angle adjustment mechanism 58 and the twist angle φ set by the twist angle adjustment mechanism 56. However, the injection angle of the wafer W may also be switched by other parameters. For example, in Figure 10, the injection angle of the wafer W may be switched by a combination of rotation angles around two intersecting rotation axes (for example, the vertical rotation axis (y-direction) and the horizontal rotation axis (x-direction) in Figure 10) within the processing surface WS of the wafer W (within the plane of the paper in Figure 10).

[0096] Figure 17 is a functional block diagram of the ion implanter 10. The control device 60 of the ion implanter 10 includes a processor 61 and a memory 63. The processor 61 controls various parts of the ion implanter 10, such as the beam deflection device 24 (beam park device 24, etc.), beam cutoff mechanism 28 (injector Faraday cup 28, etc.), beam scanning device 32, beam current measuring instruments 42, 44, 47 (side cup 42, profiler cup 44, tuning cup 47, etc.), and platen drive device 50 (including an implantation angle adjustment mechanism composed of a twist angle adjustment mechanism 56 and a tilt angle adjustment mechanism 58, and a reciprocating motion mechanism 54). The memory 63 stores programs executed by the processor 61. Based on the programs stored in the memory 63, the processor 61 controls various parts of the ion implanter 10 and executes the following series of steps.

[0097] Figure 18 is a timing chart that schematically shows the basic operation of the ion implantation apparatus 10 during the implantation process, which is executed by the processor 61 based on a program stored in memory 63. Each row in Figure 18 schematically shows the y-direction velocity of the wafer W as the workpiece of the ion implantation apparatus 10, the implantation angle of the wafer W by the implantation angle adjustment mechanism, and the operating state of the beam deflection device 24 and the beam blocking mechanism 28.

[0098] Furthermore, each column in Figure 18 shows a series of steps that constitute the basic operation of the ion implantation apparatus 10 over time. Each step corresponds to the position or range of the wafer W in the y-direction in Figure 10. Specifically, from left to right in Figure 18, in the first column, "Beam Irradiation Range," the wafer W is moving within the beam irradiation range 65 toward one non-beam irradiation range 67; in the second column, "Non-Beam Irradiation Range," the wafer W is moving within one non-beam irradiation range 67 toward the reversal end of the reciprocating movement range 69; in the third column, "Reversal End," the wafer W is stopped at the reversal end of the reciprocating movement range 69; in the fourth column, "Non-Beam Irradiation Range," the wafer W is moving within one non-beam irradiation range 67 toward the beam irradiation range 65; and in the fifth column, "Beam Irradiation Range," the wafer W is moving within the beam irradiation range 65 toward the other non-beam irradiation range 67.

[0099] In step (a) of the "Beam Irradiation Range" in the first column of Figure 18, the processor 61 moves the wafer W, which has been adjusted to a first injection angle by the injection angle adjustment mechanism, from the beam irradiation range 65 toward one of the non-beam irradiation ranges 67 (67U or 67D) by the reciprocating motion mechanism 54. The first injection angle corresponds to, for example, the state in Figure 16(a), and the ion beam B is irradiated onto the wafer W as it moves within the beam irradiation range 65 with a twist angle φ0 and a tilt angle θ0. The velocity v in the y direction of the wafer W in this "Beam Irradiation Range" y The rate may be constant, or it may be a rate controlled according to the beam current value measured by beam current meters 42, 44, and 47 in order to achieve a uniform dose distribution, as explained in relation to the injection process in Figure 11. For example, v y The size is proportional to the beam current value measured by side cups 42R and 42L during the injection process. Alternatively, v y The size may be controlled according to the measured beam current value and the position of the wafer W in the y-direction in order to achieve the desired dose non-uniformity within the wafer surface being processed.

[0100] In step (b) in the "Beam Non-Irradiation Range" in the second column of Figure 18, following step (a), the processor 61 starts changing the injection angle of the wafer W from the first injection angle to the second injection angle using the injection angle adjustment mechanism while the wafer W is moving within the beam non-irradiation range 67 after the reciprocating motion mechanism 54 has moved the wafer W at the first injection angle from the beam irradiation range 65. Step (b) may be performed a predetermined time after the wafer W enters the beam non-irradiation range 67, as shown in the figure, or it may be performed immediately after the wafer W enters the beam non-irradiation range 67. Step (b) for switching the injection angle of the wafer W may be performed each time the wafer W enters the beam non-irradiation range 67, or it may be performed in the beam non-irradiation range 67 after the wafer W has moved a predetermined number of times within the beam irradiation range 65.

[0101] Here, the entry of the wafer W into the beam-free zone 67 may be detected by the tuning cups 47 in Figure 11. While the wafer W is within the beam-free zone 65, at least one of the tuning cups 47 is shielded by the wafer W, but after the wafer W moves into the beam-free zone 67, the scan beam SB is incident on all of the tuning cups 47. Therefore, by monitoring the measured beam current of each tuning cup 47, it is possible to detect that the wafer W has entered the beam-free zone 67.

[0102] Furthermore, step (b) is preferably performed before the wafer W arrives at the inversion end of the reciprocating movement range 69, as shown in the figure. In step (b), the wafer W moving within one of the beam-non-irradiated ranges 67 is decelerated by the reciprocating motion mechanism 54 toward the inversion end of the reciprocating movement range 69, which is also the end of the beam-non-irradiated range 67 (v y →0). In the illustrated example, the wafer W is decelerated over the entire duration of the "non-beam-irradiated area," but the wafer W may be decelerated for only a portion of the duration of the "non-beam-irradiated area."

[0103] In step (c-1) at the "reversal end" in the third column of Figure 18, the processor 61, following step (b), reverses the direction of movement of the wafer W at the reversal end of one of the beam-free areas 67 and moves it toward the beam-irradiated area 65 using the reciprocating motion mechanism 54. As shown in the figure, in step (c-1), the wafer W may be stopped at the reversal end of one of the beam-free areas 67 for a predetermined stopping time. During this time, the "wafer speed" is "0". Meanwhile, the change of the wafer W from the first injection angle to the second injection angle by the injection angle adjustment mechanism, which was started in step (b), continues even while the wafer W is stopped at the reversal end. Furthermore, after the reversal of the direction of movement of the wafer W in step (c-1), the wafer W moving within one of the beam-free areas 67 is accelerated toward the beam-irradiated area 65 by the reciprocating motion mechanism 54 (0→-v y ) is performed. In the illustrated example, the wafer W is accelerated over the entire time of the "non-beam-irradiated area," but the wafer W may be accelerated over only a portion of the time of the "non-beam-irradiated area."

[0104] In step (c-2) in the "Beam Non-Irradiation Range" in the fourth column of Figure 18, following step (b), while the wafer W is moving within the beam non-irradiation range 67 by the reciprocating motion mechanism 54 before returning from one beam non-irradiation range 67 to the beam irradiation range 65, the processor 61 completes the change of the wafer W from the first injection angle to the second injection angle by the injection angle adjustment mechanism started in step (b). Note that the change of the wafer W from the first injection angle to the second injection angle by the injection angle adjustment mechanism may also be completed while the wafer W is moving within one beam non-irradiation range 67 toward the reversal end of the reciprocating movement range 69 in the "Beam Non-Irradiation Range" in the second column, or while the wafer W is stopped at the reversal end of the reciprocating movement range 69 in the "Reversal End" in the third column.

[0105] In the fifth column of Figure 18, the “Beam Irradiation Range,” the processor 61 moves the wafer W, which has been adjusted to a second injection angle by step (c-2), within the beam irradiation range 65 toward the other non-beam irradiation range 67 (67D or 67U) by the reciprocating motion mechanism 54. The second injection angle corresponds, for example, to the state in Figure 16(b), and the ion beam B is irradiated onto the wafer W as it moves within the beam irradiation range 65 with a twist angle φ0 + 90 degrees and a tilt angle θ0. The velocity of the wafer W in the y direction in this “Beam Irradiation Range” is -v y The value (indicated by a "-" in the first column, which indicates a velocity in the opposite direction to the "beam irradiation range") may be constant, or it may be a velocity controlled according to the beam current value measured by beam current meters 42, 44, and 47 in order to achieve a uniform dose distribution, as explained in relation to the injection process in Figure 11. For example, -v y The size is proportional to the beam current value measured by side cups 42R and 42L during the injection process. Or, -v y The size may be controlled according to the measured beam current value and the position of the wafer W in the y-direction in order to achieve the desired dose non-uniformity within the wafer surface being processed.

[0106] According to this embodiment, the change to the second implantation angle begins before the wafer W at the first implantation angle moves from the beam irradiation area 65 to the beam non-irradiation area 67 and reaches the inversion edge of the beam non-irradiation area 67 (step (b)), and the change to the second implantation angle is completed while the wafer W is moving or stopped within the beam non-irradiation area 67 before returning from the beam non-irradiation area 67 to the beam irradiation area 65 (step (c-2)). In this way, by performing the movement and reversal of the direction of movement of the wafer W within the beam non-irradiation area 67 and the change in the implantation angle in parallel, the dwell time of the wafer W in the beam non-irradiation area 67 can be shortened. As a result, the dwell time of the wafer W in the beam irradiation area 65 where the scan beam SB is irradiated becomes relatively longer, thus improving the efficiency of the ion implantation process.

[0107] In order to complete the change from the first injection angle to the second injection angle while the wafer W remains in the beam-non-irradiated area 67, the sum of the time T1 for the wafer W to move within the beam-non-irradiated area 67 toward the inversion edge of the beam-non-irradiated area 67, the stopping time T2 at the inversion edge, and the time T3 for the wafer W to move within the beam-non-irradiated area 67 toward the beam-irradiated area 65 is preferably greater than or equal to the time required for the wafer W to change from the first injection angle to the second injection angle by the injection angle adjustment mechanism. Specifically, T1+T2+T3 is preferably 0.05 seconds or more and 1 second or less, 0.2 seconds or more and 0.8 seconds or less, 0.3 seconds or more and 0.6 seconds or less, etc. In particular, the stopping time T2 at the inversion edge is preferably greater than 0 seconds and 0.45 seconds or less.

[0108] If the change from the first injection angle to the second injection angle of wafer W can be completed by the injection angle adjustment mechanism without stopping wafer W at the inversion end, the stay time T1+T2+T3 in the beam-free area 67 of wafer W can be minimized (T2=0). On the other hand, if the change from the first injection angle to the second injection angle of wafer W by the injection angle adjustment mechanism cannot be completed by the round-trip movement time T1+T3 in the beam-free area 67 of wafer W, then wafer W should be stopped at the inversion end for an additional time T2 required for the injection angle change. In other words, the stopping time T2 at the inversion end of wafer W can be flexibly set from the perspective of completing the change in injection angle.

[0109] The "Beam Deflection Device" in the third row and the "Beam Blocking Mechanism" in the fourth row of Figure 18 are controlled by the processor 61 to ensure that the ion beam B is retracted so that the scan beam SB does not accidentally irradiate the wafer W while the injection angle of the wafer W within the beam non-irradiation area 67 is being changed. "ON" and "OFF" in "Beam Deflection Device" indicate the operating state of the beam deflection device 24. When it is "ON", the beam deflection device 24 deflects the ion beam B in a direction where irradiation is not possible, and when it is "OFF", the beam deflection device 24 is not operating and the ion beam B moves in a direction where irradiation is possible. "ON" and "OFF" in "Beam Blocking Mechanism" indicate the operating state of the beam blocking mechanism 28. When it is "ON", the beam blocking mechanism 28 is in a blocking state where it physically blocks the ion beam B, and when it is "OFF", the beam blocking mechanism 28 is in an unblocking state where it allows the ion beam B to pass through.

[0110] In step (d), the processor 61 switches the beam deflection device 24 to the non-irradiation state "ON" while the wafer W is moving within the beam non-irradiation range 67 by the reciprocating motion mechanism 54 in step (b), and before the injection angle adjustment mechanism starts changing the wafer W from the first injection angle to the second injection angle. In step (f), the processor 61 switches the beam blocking mechanism 28 to the blocked state "ON" after step (d). It is preferable that step (f) is performed before the injection angle adjustment mechanism starts changing the wafer W from the first injection angle to the second injection angle in step (b). The ion beam B deflected by the beam deflection device 24 moves in the non-irradiation direction, and the beam blocking mechanism 28 physically blocks the ion beam B in case the beam deflection device 24 does not operate properly, thus ensuring that the scan beam SB is not accidentally irradiated onto the wafer W while the injection angle of the wafer W within the beam non-irradiation range 67 is being changed.

[0111] In step (e), the processor 61 switches the beam deflection device 24 to the irradiation-enabled state "OFF" while the wafer W is moving within the beam-non-irradiated area 67 by the reciprocating motion mechanism 54 in step (c-1), and after the change of the wafer W from the first injection angle to the second injection angle by the injection angle adjustment mechanism is completed in step (c-2). In step (g), the processor 61 switches the beam blocking mechanism 28 to the non-blocking state "OFF" before step (e). It is preferable that step (g) is performed after the change of the wafer W from the first injection angle to the second injection angle by the injection angle adjustment mechanism is completed in step (c-2).

[0112] Next, we will explain some variations of the basic operation in the implantation process of the ion implantation apparatus 10 described above.

[0113] In the first modified example, in addition to the beam shutoff mechanism 28, a first beam current meter 46 and / or a second beam current meter 42 are used. If the first beam current meter 46 (such as a beam stopper 46 configured as a beam current meter) measures the beam current of the ion beam directed toward the irradiable direction and does not measure a beam current equal to or greater than a first predetermined value, the processor 61 may determine that irradiation is impossible and switch the beam shutoff mechanism 28 to the shutoff state. That is, if the beam current measured by the first beam current meter 46 is less than a first predetermined value, there is a risk that the intensity of the ion beam used for ion implantation in the implantation chamber 16 is insufficient, so the beam shutoff mechanism 28 is switched to the shutoff state and the ion implantation process is interrupted or stopped. Alternatively, if the second beam current meter 42 (such as a side cup 42) or a tuning cup 47 measures a beam current equal to or greater than a first predetermined value, the processor 61 may determine that irradiation is impossible and switch the beam shutoff mechanism 28 to the shutoff state.

[0114] If the second beam current measuring instrument 42 (side cup 42, etc.), which measures the beam current of the ion beam directed in the direction that cannot be irradiated, measures a beam current of a second predetermined value or higher, the processor 61 may determine that the ion beam is in an irradiation-non-functional state and switch the beam shut-off mechanism 28 to the shut-off state. In other words, if the beam current measured by the second beam current measuring instrument 42 is greater than or equal to the second predetermined value, there is a risk that the intensity of the ion beam not used for ion implantation in the implantation chamber 16 is excessive, so the beam shut-off mechanism 28 is switched to the shut-off state and the ion implantation process is interrupted or stopped. It is preferable that the second predetermined value be set such that the beam current density calculated from it is greater than the beam current density calculated from the first predetermined value.

[0115] In the second modified example, the beam scanning device 32 is also used as a beam deflection device 24. For example, the beam scanning device 32 is used to perform the functions of the beam deflection device 24, either in place of or in addition to the beam park device 24 that functioned as a beam deflection device 24 in Figures 1 and 2. In this case, the beam deflection device 24 and the beam scanning device 32 are the same device. Figure 19 schematically shows an example in which the beam scanning function as a beam scanning device 32 and the beam deflection function as a beam deflection device 24 are realized with a single beam scanning device 32.

[0116] When the beam scanning device 32 performs its intended beam scanning function, it reciprocates the ion beam irradiated onto the wafer W within a predetermined scanning angle range in the x-direction (irradiation range 66 in Figure 10). Here, the scanning angle range is an angular range that includes the irradiable direction (the direction of the beamline A that can reach the wafer), and the θ2 shown is the maximum scanning angle at which the outermost angle of the scanning angle range makes contact with the reference trajectory direction (the direction of beamline A in a non-scanning state where the voltage applied between the scanning electrode pair of the beam scanning device 32 is approximately zero). In other words, the scanning angle range of the beam scanning device 32 is within ±θ2 of the reference trajectory direction.

[0117] On the other hand, when the beam scanning device 32 functions as a beam deflection device 24, it deflects the ion beam in a direction outside the scanning angle range where irradiation is impossible. Here, the deflection angle θ1 of the ion beam is the angle that the direction of no irradiation makes with the reference trajectory direction, and is greater than the maximum scanning angle θ2 (θ1 > θ2). Since the wafer W is not placed in the path of the ion beam deflected at a deflection angle θ1, the deflection angle θ1 is the direction in which the ion beam cannot irradiate the wafer W. Note that the beam scanning device 32, which functions as a beam deflection device 24, may also deflect the ion beam at a deflection angle of -θ1. In addition, a beam dump or the like may be provided in the path of the ion beam deflected at a deflection angle θ1 (or -θ1) to which the ion beam collides and is shielded.

[0118] In the "beam irradiation range" of the basic operation of the injection process shown in Figure 18, the beam scanning device 32 performs its original beam scanning function, scanning the wafer W back and forth within the scanning angle range (-θ2 to +θ2) with the ion beam irradiated onto it. In the "non-irradiated beam range" and "reversal end" of the basic operation of the injection process shown in Figure 18, the beam scanning device 32 functions as a beam deflection device 24, deflecting the ion beam in a direction outside the scanning angle range where irradiation is impossible (θ1 or -θ1).

[0119] The present invention has been described above based on embodiments. The embodiments are illustrative, and it will be understood by those skilled in the art that various modifications are possible in combinations of their components and processing processes, and that such modifications also fall within the scope of the present invention.

[0120] The functional configurations of each device described in the embodiments can be realized using hardware resources, software resources, or through the collaboration of hardware and software resources. Hardware resources can include processors, ROMs, RAMs, and other LSIs. Software resources can include operating systems, applications, and other programs. [Explanation of symbols]

[0121] 10 Ion implanter, 12 Ion generator, 14 Beamline equipment, 16 Implantation chamber, 23 Mass spectrometry slit, 24 Beam deflection device, 28 Beam cutoff mechanism, 32 Beam scanning device, 42 Second beam current meter, 46 First beam current meter, 47 Tuning cup, 50 Platen drive device, 52 Wafer holder, 54 Reciprocating motion mechanism, 56 Twist angle adjustment mechanism, 58 Tilt angle adjustment mechanism, 60 Control device, 61 Processor, 63 Memory, 65 Beam irradiation range, 67 Beam non-irradiation range, 69 Reciprocating movement range.

Claims

1. A support mechanism that supports the object to be treated by the ion beam, An injection angle adjustment mechanism capable of adjusting the injection angle of the workpiece supported by the support mechanism relative to the ion beam, A drive mechanism for reciprocating the support mechanism in a direction intersecting the ion beam, wherein the reciprocating movement range includes a beam irradiation range in which the ion beam irradiates at least a portion of the workpiece, and a beam non-irradiation range adjacent to at least one end of the beam irradiation range in which the workpiece is not irradiated by the ion beam. A processor that controls the injection angle adjustment mechanism and the drive mechanism, The memory where the program is stored, Equipped with, The processor, based on the program, (a) The step of moving the workpiece, which has been adjusted to a first injection angle by the injection angle adjustment mechanism, from the beam irradiation area to the beam non-irradiation area by the drive mechanism, (b) Following step (a), the drive mechanism moves the workpiece at the first injection angle from the beam-irradiated area to the beam-non-irradiated area, moves within the beam-non-irradiated area, reverses the direction of movement of the workpiece at the edge of the beam-non-irradiated area, and moves it toward the beam-irradiated area, (c) In step (b), while the drive mechanism is moving within the beam non-irradiation range, the injection angle adjustment mechanism starts changing the workpiece from the first injection angle to a second injection angle different from the first injection angle, and completes the change to the second injection angle while step (b) is being performed. An ion implantation device that performs this operation.

2. The ion implantation apparatus according to claim 1, wherein the beam non-irradiation area includes a first beam non-irradiation area adjacent to one end of the beam irradiation area and a second beam non-irradiation area adjacent to the other end of the beam irradiation area.

3. The ion implantation apparatus according to claim 1 or 2, wherein step (b) is performed each time the object to be treated enters the beam irradiation range.

4. The ion implantation apparatus according to claim 1 or 2, wherein step (b) is performed in the non-beam-irradiated area that the workpiece enters after moving a predetermined number of times within the beam irradiation area.

5. The ion implantation apparatus according to any one of claims 1 to 4, wherein in step (b), the object to be treated is stopped at the edge of the beam-non-irradiated area for a predetermined stop time.

6. The ion implantation apparatus according to claim 5, wherein in step (b), the sum of the time it takes for the workpiece to move within the beam-free area toward the edge of the beam-free area, the stopping time, and the time it takes for the workpiece to move within the beam-free area toward the beam-irradiated area is equal to or greater than the time required for the implantation angle adjustment mechanism to change the workpiece from the first implantation angle to the second implantation angle.

7. The ion implantation apparatus according to claim 6, wherein in step (b), the sum of the time during which the object to be processed moves within the beam-free area toward the edge of the beam-free area, the stopping time, and the time during which the object to be processed moves within the beam-free area toward the beam-irradiated area is 0.05 seconds or more and 1 second or less.

8. The ion implantation apparatus according to claim 7, wherein the aforementioned stop time is greater than 0 seconds and less than or equal to 0.45 seconds.

9. The ion implantation apparatus according to any one of claims 5 to 8, wherein in step (c), at least one of the changes and completion of the change of the workpiece from the first implantation angle to the second implantation angle by the implantation angle adjustment mechanism is performed while the drive mechanism is moving within the beam-free irradiation range.

10. The injection angle adjustment mechanism includes a twist angle adjustment mechanism that adjusts the twist angle of the workpiece supported by the support mechanism, with the axis of rotation being a normal perpendicular to the workpiece surface at the center of the workpiece's workpiece surface. The twist angle adjustment mechanism adjusts the twist angle at the first injection angle to a first twist angle, and adjusts the twist angle at the second injection angle to a second twist angle that is different from the first twist angle. An ion implantation apparatus according to any one of claims 1 to 9.

11. The ion implantation apparatus according to claim 10, wherein the difference between the first twist angle and the second twist angle is greater than 0 degrees and 180 degrees or less.

12. The ion implantation apparatus according to claim 10 or 11, wherein when the processor performs steps (a) to (c) N times (where N is a natural number of 2 or more), the difference between the first twist angle and the second twist angle is equal for all N times.

13. The ion implantation apparatus according to claim 12, wherein N is an even number between 2 and 32.

14. The ion implantation apparatus according to claim 13, wherein the difference between the first twist angle and the second twist angle is the angle obtained by dividing 360 degrees by N.

15. (a) A step of moving a workpiece, which has been adjusted to a first injection angle with respect to the ion beam, from a beam irradiation range in which the ion beam irradiates at least a portion of the workpiece, toward a beam non-irradiation range adjacent to at least one end of the beam irradiation range in which the ion beam does not irradiate the workpiece; (b) Following step (a), the workpiece at the first injection angle moves from the beam-irradiated area to the beam-non-irradiated area, then moves within the beam-non-irradiated area, and at the edge of the beam-non-irradiated area, reverses the direction of movement of the workpiece and moves toward the beam-irradiated area, (c) In step (b), while moving within the beam-non-irradiated area, the process begins to change the workpiece from the first injection angle to a second injection angle different from the first injection angle, and completes the change to the second injection angle while performing step (b), An ion implantation method comprising the following features.

16. The ion implantation method according to claim 15, wherein the beam non-irradiated area includes a first beam non-irradiated area adjacent to one end of the beam irradiation area and a second beam non-irradiated area adjacent to the other end of the beam irradiation area.

17. The ion implantation method according to claim 15 or 16, wherein step (b) is performed each time the object to be treated enters the beam irradiation range.

18. The ion implantation method according to claim 15 or 16, wherein step (b) is performed in the non-beam-irradiated area that the workpiece enters after moving a predetermined number of times within the beam irradiation area.

19. The ion implantation method according to any one of claims 15 to 18, wherein in step (b), the object to be treated is stopped at the edge of the beam-non-irradiated area for a predetermined stop time.

20. The ion implantation method according to claim 19, wherein in step (b), the sum of the time the workpiece moves within the beam-free area toward the edge of the beam-free area, the stopping time, and the time the workpiece moves within the beam-free area toward the beam-irradiated area is equal to or greater than the time required to change the workpiece from the first implantation angle to the second implantation angle.

21. The ion implantation method according to claim 19 or 20, wherein in step (c), at least one of changing and completing to the first implantation angle of a workpiece supported by a support mechanism that supports a workpiece irradiated with an ion beam, by an implantation angle adjustment mechanism capable of adjusting the implantation angle of the workpiece with respect to the ion beam, is performed while a drive mechanism that reciprocates the support mechanism in a direction intersecting the ion beam is moving within the beam-non-irradiated area.

Images