Ion implantation method, ion implantation apparatus, and semiconductor device manufacturing method

Abstract

To provide a technique for improving productivity in an ion implantation process.SOLUTION: An ion implantation method includes: generating a first scan beam, on the basis of a first scan signal; measuring a beam current of the first scan beam by using a beam measurement device at a plurality of measurement positions; calculating a beam current matrix, on the basis of a time waveform of the measured beam current and a time waveform of scan command values determined in the first scan signal; calculating first beam current density distribution of the first scan beam by performing time integration on the measured beam current; correcting a value of each component of the beam current matrix, on the basis of the first beam current density distribution; and generating a second scan signal for achieving a target beam current density distribution, on the basis of the corrected beam current matrix.SELECTED DRAWING: Figure 18

Description

[Technical field]

[0001] The present disclosure relates to an ion implantation method, an ion implantation apparatus, and a method for manufacturing a semiconductor device. [Background technology]

[0002] In the manufacturing process of semiconductor devices, a process of implanting ions into semiconductor wafers (also called an ion implantation process) is standard for the purpose of changing the conductivity of the semiconductor or changing the crystal structure of the semiconductor. The equipment used in the ion implantation process is called an ion implanter. In addition to "uniform implantation" which makes the two-dimensional dose distribution uniform within the wafer processing surface, "non-uniform implantation" which intentionally makes the two-dimensional dose distribution non-uniform may be required.

[0003] The two-dimensional dose distribution in the wafer processing plane is controlled by changing at least one of the beam scan speed and the wafer scan speed according to the beam irradiation position in the wafer processing plane. For example, the one-dimensional dose distribution in the beam scan direction is controlled by adjusting the beam scan speed distribution in the beam scan direction. The beam scan speed distribution for realizing the target one-dimensional dose distribution is calculated based on the measured value and the target value of the beam current density distribution in the beam scan direction. The calculation of the beam scan speed distribution utilizes the relationship that the beam current density is inversely proportional to the beam scan speed (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-41595 A Summary of the Invention [Problem to be solved by the invention]

[0005] When the beam size is sufficiently small and the beam current is constant and independent of position, a simple inverse proportional relationship is established between the beam current density distribution and the beam scan velocity distribution, so that the beam scan velocity distribution for achieving the target value can be easily calculated. However, when the beam size becomes large, the simple inverse proportional relationship is difficult to establish, and the measured value of the beam current density distribution obtained by the calculated beam scan velocity distribution may deviate significantly from the target value. In this case, it is necessary to repeat measurements and calculations to obtain the beam scan velocity distribution for achieving the target value, and the adjustment takes time. In some cases, the adjustment of the beam scan velocity distribution may fail. The increase in the time required for adjustment or the failure of the adjustment leads to a decrease in productivity in the ion implantation process.

[0006] An exemplary object of an embodiment of the present disclosure is to provide a technique for improving productivity in an ion implantation process. [Means for solving the problem]

[0007] An ion implantation method according to one embodiment of the present disclosure includes generating a first scan beam by scanning a spot-shaped ion beam back and forth in a predetermined direction based on a first scan signal, measuring the beam current of the first scan beam at a plurality of different measurement positions in the predetermined direction using a beam measurement device, calculating a beam current matrix having beam current values ​​for a plurality of different positions and a plurality of scan command values ​​in the predetermined direction based on a time waveform of the beam current measured by the beam measurement device and a time waveform of a scan command value defined in the first scan signal, calculating a first beam current density distribution in the predetermined direction of the first scan beam by integrating the measured beam current over time, correcting values ​​of each component of the beam current matrix based on the first beam current density distribution, and generating a second scan signal for realizing a target beam current density distribution based on the corrected beam current matrix.

[0008] Another aspect of the present disclosure is an ion implantation apparatus. The apparatus includes a beam scanning device that generates a first scan beam by scanning a spot-shaped ion beam back and forth in a predetermined direction based on a first scan signal, a beam measurement device configured to measure the beam current of the first scan beam at a plurality of measurement positions different in the predetermined direction, and a control device that generates a scan signal that determines a time waveform of a scan command value corresponding to a scan position in the predetermined direction based on the measurement by the beam measurement device. The control device is configured to acquire the time waveform of the beam current of the first scan beam measured at the plurality of measurement positions, calculate a beam current matrix having beam current values ​​corresponding to positions in the predetermined direction and scan command values ​​as components based on the acquired time waveform of the beam current and the time waveform of the scan command value determined by the first scan signal, calculate a first beam current density distribution in the predetermined direction of the first scan beam by time integrating the acquired beam current, correct values ​​of each component of the beam current matrix based on the first beam current density distribution, and generate a second scan signal for realizing a target beam current density distribution based on the corrected beam current matrix.

[0009] Yet another aspect of the present disclosure is a method for manufacturing a semiconductor device, the method including an ion implantation step, the ion implantation step including: generating a first scan beam by scanning a spot-shaped ion beam back and forth in a predetermined direction based on a first scan signal; measuring a beam current of the first scan beam at a plurality of measurement positions different in the predetermined direction; calculating a beam current matrix having beam current values ​​for a plurality of positions different in the predetermined direction and a plurality of scan command values ​​as components based on a time waveform of the measured beam current and a time waveform of a scan command value defined in the first scan signal; calculating a first beam current density distribution in the predetermined direction of the first scan beam by integrating the measured beam current with time; correcting values ​​of each component of the beam current matrix based on the first beam current density distribution; generating a second scan signal for realizing a target beam current density distribution based on the corrected beam current matrix; generating a second scan beam by scanning an ion beam back and forth in the predetermined direction based on the second scan signal; and irradiating a semiconductor wafer with the second scan beam.

[0010] Any combination of the above components or mutual substitution of the components or expressions of the present disclosure between methods, devices, systems, etc. are also valid aspects of the present disclosure. Effect of the Invention

[0011] According to a non-limiting exemplary embodiment of the present invention, a technique for improving productivity in an ion implantation process can be provided. [Brief description of the drawings]

[0012] [Figure 1] 1 is a top view showing a schematic configuration of an ion implantation apparatus according to an embodiment; [Diagram 2] FIG. 2 is a side view showing a schematic configuration of the ion implantation apparatus of FIG. [Diagram 3] FIG. 2 is a diagram illustrating an example of a configuration of a control device. [Figure 4]FIG. 2 is a top view showing a schematic configuration of the interior of the implantation processing chamber. [Diagram 5] FIG. 2 is a diagram illustrating a data structure of an implantation recipe. [Figure 6] 6(a) and (b) are diagrams showing schematic diagrams of two-dimensional dose distribution. [Figure 7] 13A and 13B are diagrams illustrating an example of a correction function file and a correlation information file. [Figure 8] 11 is a table illustrating an example of a correlation information file. [Figure 9] FIG. 1 is a schematic diagram of a multi-step injection. [Figure 10] FIG. 2 is a block diagram illustrating a functional configuration of a control device. [Figure 11] FIG. 2 is a diagram illustrating a beam current matrix according to the embodiment. [Figure 12] FIG. 11 is a diagram showing a schematic diagram of measurement of beam current distribution with respect to a scan command value. [Figure 13] FIG. 13 is a diagram showing a schematic diagram of measurement of beam current distribution with respect to position. [Figure 14] 1 is a graph showing a schematic relationship between a beam current matrix and a beam current density distribution. [Figure 15] 4 is a graph showing an example of time waveforms of a first scanning signal and a beam current. [Figure 16] FIG. 2 is a circuit diagram showing an example of a configuration of a beam current measuring circuit. [Figure 17] 11 is a graph showing an example of a calculated value of a beam current density distribution based on a beam current matrix before correction and an actual measured value of the beam current density distribution. [Figure 18] 4 is a flowchart showing an example of an ion implantation method according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, with reference to the drawings, detailed description will be given of the ion implantation method, the ion implantation apparatus, and the semiconductor device manufacturing method according to the present disclosure. In the description of the drawings, the same elements are given the same reference numerals, and duplicated descriptions are omitted as appropriate. In addition, the configurations described below are examples, and do not limit the scope of the present invention in any way.

[0014] Before describing the embodiment in detail, an overview will be given. The embodiment relates to a technique for controlling a two-dimensional dose distribution of an ion beam irradiated onto a semiconductor wafer, and in particular, to a technique for controlling a one-dimensional beam current density distribution in a beam scan direction. The beam current density distribution in the beam scan direction is controlled by adjusting the beam scan speed distribution of a beam scan that scans an ion beam back and forth. In the embodiment, instead of utilizing the simple relationship that the beam current density distribution and the beam scan speed distribution have an inversely proportional relationship, the relationship between the beam current density distribution and the beam scan speed distribution is defined using a "beam current matrix."

[0015] The beam current matrix has components of the scan command value Vi and the beam current value I(Vi,Xj)=Iij for the position Xj in the x direction, and represents a set of beam current distributions (i.e., beam shapes) in the x direction of the spot-shaped ion beams that constitute the scan beam. The beam current density distribution J(Xj) for the position Xj in the x direction is expressed by the following equation (1).

number

[0016] In this embodiment, the beam dwell time Δti for realizing a target beam current density distribution J(Xj) is calculated using the beam current matrix Iij, and a scan signal is generated based on the beam dwell time Δti held in the scan command value Vi in the beam scan. Since the beam current matrix contains all information related to the beam shape of the spot-shaped ion beam in the x direction, even if the beam size (i.e., the spot size) of the ion beam in the x direction is large, the scan signal for realizing the target beam current density distribution J(Xj) can be calculated with high accuracy in a short time.

[0017] In this embodiment, the value of each component Iij of the beam current matrix is ​​further corrected based on the measured value of the beam current density distribution, and a scan signal for realizing a target beam current density distribution is generated based on the corrected beam current matrix. By using the corrected beam current matrix, the beam current matrix can be adapted to the actual measured value of the beam current density distribution. By generating a scan signal based on the corrected beam current matrix, the scan signal for realizing a target beam current density distribution can be calculated with high accuracy in a short time.

[0018] Fig. 1 is a top view showing an ion implantation apparatus 10 according to an embodiment, and Fig. 2 is a side view showing a schematic configuration of the ion implantation apparatus 10. The ion implantation apparatus 10 is configured to perform an ion implantation process on a surface of a workpiece. The workpiece is, for example, a substrate, such as a semiconductor wafer. For convenience of explanation, the workpiece may be referred to as a wafer W in this specification, but this is not intended to limit the target of the implantation process to a specific object.

[0019] The ion implantation apparatus 10 is configured to irradiate the entire processing surface of the wafer W with a spot-shaped ion beam by scanning the beam back and forth in one direction and moving the wafer W back and forth in a direction perpendicular to the scanning direction. For convenience of explanation in this specification, the direction of travel of the ion beam along the designed beamline A is defined as the z direction, and a plane perpendicular to the z direction is defined as the xy plane. When scanning the wafer W with the ion beam, the scanning direction of the beam is defined as the x direction, and the direction perpendicular to the z direction and the x direction is defined as the y direction. Therefore, the beam is scanned back and forth in the x direction, and the wafer W is moved back and forth in the y direction.

[0020] The ion implantation apparatus 10 includes an ion generator 12, a beamline device 14, an implantation processing chamber 16, and a wafer transport device 18. The ion generator 12 is configured to provide an ion beam to the beamline device 14. The beamline device 14 is configured to transport the ion beam from the ion generator 12 to the implantation processing chamber 16. The implantation processing chamber 16 accommodates a wafer W to be implanted, and performs an implantation process in which the wafer W is irradiated with an ion beam provided from the beamline device 14. The wafer transport device 18 is configured to carry an unprocessed wafer before implantation processing into the implantation processing chamber 16 and carry a processed wafer after implantation processing out of the implantation processing chamber 16. The ion implantation apparatus 10 includes a vacuum exhaust system (not shown) for providing a desired vacuum environment to the ion generator 12, the beamline device 14, the implantation processing chamber 16, and the wafer transport device 18.

[0021] The beamline device 14 includes, in order from the upstream side of the beamline A, a mass analysis unit 20, a beam park device 24, a beam shaping unit 30, a beam scanning unit 32, a beam collimating unit 34, and an angular energy filter (AEF) 36. Note that the upstream side of the beamline A refers to the side closer to the ion generation device 12, and the downstream side of the beamline A refers to the side closer to the implantation processing chamber 16 (or the beam stopper 46).

[0022] The mass analysis unit 20 is provided downstream of the ion generator 12, and is configured to select, by mass analysis, a required ion species from the ion beam extracted from the ion generator 12. The mass analysis unit 20 has a mass analysis magnet 21, a mass analysis lens 22, and a mass analysis slit 23.

[0023] The mass analysis magnet 21 applies a magnetic field to the ion beam extracted from the ion generator 12, and deflects the ion beam in different paths depending on the value of the mass-to-charge ratio M=m / q (m is mass, q is charge) of the ions. For example, the mass analysis magnet 21 applies a magnetic field in the y direction (-y direction in Figs. 1 and 2) to the ion beam to deflect the ion beam in the x direction. The magnetic field strength of the mass analysis magnet 21 is adjusted so that an ion species having a desired mass-to-charge ratio M passes through the mass analysis slit 23.

[0024] The mass analysis lens 22 is provided downstream of the mass analysis magnet 21, and is configured to adjust the converging / diverging force on the ion beam. The mass analysis lens 22 adjusts the convergence position in the beam traveling direction (z direction) of the ion beam passing through the mass analysis slit 23, and adjusts the mass resolution M / dM of the mass analysis unit 20. Note that the mass analysis lens 22 is not an essential component, and the mass analysis unit 20 does not necessarily need to be provided with the mass analysis lens 22.

[0025] The mass analysis slit 23 is provided downstream of the mass analysis lens 22, at a position away from the mass analysis lens 22. The mass analysis slit 23 is configured so that the direction of beam deflection by the mass analysis magnet 21 (x direction) is the slit width, and has an opening 23a that is relatively short in the x direction and relatively long in the y direction.

[0026] The mass analysis slit 23 may be configured so that the slit width is variable in order to adjust the mass resolution. The mass analysis slit 23 may be configured so that the slit width is adjustable by being composed of two beam shields movable in the slit width direction and by changing the distance between the two beam shields. The mass analysis slit 23 may be configured so that the slit width is variable by switching to one of a plurality of slits having different slit widths.

[0027] The beam park device 24 is configured to temporarily evacuate the ion beam from the beam line A and block the ion beam heading toward the downstream implantation processing chamber 16 (or wafer W). The beam park device 24 can be placed at any position along the beam line A, for example, between the mass analysis lens 22 and the mass analysis slit 23. Since a certain distance is required between the mass analysis lens 22 and the mass analysis slit 23, by placing the beam park device 24 therebetween, the length of the beam line A can be made shorter than when it is placed at another position, and the overall size of the ion implantation apparatus 10 can be reduced.

[0028] The beam park device 24 includes a pair of park electrodes 25 (25a, 25b) and a beam dump 26. The pair of park electrodes 25a, 25b face each other across the beamline A, and face each other in a direction (y direction) perpendicular to the beam deflection direction (x direction) of the mass analysis magnet 21. The beam dump 26 is provided downstream of the beamline A from the park electrodes 25a, 25b, and is provided away from the beamline A in the opposing direction of the park electrodes 25a, 25b.

[0029] The first park electrode 25a is disposed above the beamline A in the direction of gravity, and the second park electrode 25b is disposed below the beamline A in the direction of gravity. The beam dump 26 is provided at a position below the beamline A in the direction of gravity, and is disposed below the opening 23a of the mass analysis slit 23 in the direction of gravity. The beam dump 26 is formed, for example, in a portion of the mass analysis slit 23 where the opening 23a is not formed. The beam dump 26 may be formed as a separate entity from the mass analysis slit 23.

[0030] The beam park device 24 deflects the ion beam by utilizing an electric field applied between a pair of park electrodes 25a, 25b, and evacuates the ion beam from the beamline A. For example, by applying a negative voltage to the second park electrode 25b with reference to the potential of the first park electrode 25a, the ion beam is deflected downward in the direction of gravity from the beamline A and made to enter the beam dump 26. In FIG. 2, the trajectory of the ion beam toward the beam dump 26 is indicated by a dashed line. Moreover, the beam park device 24 makes the ion beam pass downstream along the beamline A by setting the pair of park electrodes 25a, 25b to the same potential. The beam park device 24 is configured to be operable by switching between a first mode in which the ion beam passes downstream and a second mode in which the ion beam is made to enter the beam dump 26.

[0031] An injector Faraday cup 28 is provided downstream of the mass analysis slit 23. The injector Faraday cup 28 is configured so as to be able to be inserted into and removed from the beamline A by the operation of an injector driver 29. The injector driver 29 moves the injector Faraday cup 28 in a direction (e.g., the y direction) perpendicular to the direction in which the beamline A extends. When the injector Faraday cup 28 is placed on the beamline A as shown by the dashed line in FIG. 2, it blocks the ion beam heading downstream. On the other hand, when the injector Faraday cup 28 is removed from the beamline A as shown by the solid line in FIG. 2, the blockage of the ion beam heading downstream is released.

[0032] The injector Faraday cup 28 is configured to measure the beam current of the ion beam mass analyzed by the mass analysis unit 20. The injector Faraday cup 28 can measure the mass analysis spectrum of the ion beam by measuring the beam current while changing the magnetic field strength of the mass analysis magnet 21. The mass resolution of the mass analysis unit 20 can be calculated using the measured mass analysis spectrum.

[0033] The beam shaping unit 30 includes a converging / diverging device such as a converging / diverging quadrupole lens (Q lens) and is configured to shape the ion beam that has passed through the mass analysis unit 20 into a desired cross-sectional shape. The beam shaping unit 30 includes, for example, an electric field type triple-stage quadrupole lens (also called a triplet Q lens) and has three quadrupole lenses 30a, 30b, and 30c. The beam shaping unit 30 can independently adjust the convergence or divergence of the ion beam in the x direction and the y direction by using the three lens devices 30a to 30c. The beam shaping unit 30 may include a magnetic field type lens device, or may include a lens device that uses both an electric field and a magnetic field to shape the beam.

[0034] The beam scanning unit 32 is a beam deflection device configured to provide reciprocating beam scanning and scans the shaped ion beam in the x-direction. The beam scanning unit 32 has a pair of scanning electrodes facing each other in the beam scanning direction (x-direction). The pair of scanning electrodes is connected to a variable voltage power supply (not shown), and the voltage applied between the pair of scanning electrodes is periodically changed to change the electric field generated between the electrodes and deflect the ion beam at various angles. As a result, the ion beam is scanned over the entire scanning range in the x-direction. In FIG. 1, the arrow X illustrates the beam scanning direction and scanning range, and multiple trajectories of the ion beam in the scanning range are indicated by dashed lines. Note that the beam scanning unit 32 may be replaced by another beam scanning device, and the beam scanning device may be configured as a magnet device that utilizes a magnetic field.

[0035] The beam collimator 34 is configured to make the traveling direction of the scanned ion beam parallel to the designed trajectory of the beamline A. The beam collimator 34 has a plurality of arc-shaped collimating lens electrodes each having a passage slit for the ion beam at the center in the y direction. The collimating lens electrodes are connected to a high-voltage power supply (not shown), and an electric field generated by applying a voltage acts on the ion beam to align the traveling direction of the ion beam in parallel. The beam collimator 34 may be replaced with another beam collimating device, and the beam collimating device may be configured as a magnet device that utilizes a magnetic field.

[0036] Downstream of the beam collimator 34, an AD (Accel / Decel) column (not shown) for accelerating or decelerating the ion beam may be provided.

[0037] The angular energy filter (AEF) 36 is configured to analyze the energy of the ion beam, deflect ions of a required energy downward, and guide them to the implantation process chamber 16. The angular energy filter 36 has an AEF electrode pair for electric field deflection. The AEF electrode pair is connected to a high-voltage power supply (not shown). In FIG. 2, the ion beam is deflected downward by applying a positive voltage to the upper AEF electrode and a negative voltage to the lower AEF electrode. The angular energy filter 36 may be configured with a magnet device for magnetic field deflection, or may be configured with a combination of an AEF electrode pair for electric field deflection and a magnet device.

[0038] In this manner, the beamline device 14 supplies the ion beam to be irradiated onto the wafer W to the implantation processing chamber 16. In this embodiment, the ion generation device 12 and the beamline device 14 are also referred to as a beam generation device. The beam generation device is configured to generate an ion beam for achieving desired implantation conditions by adjusting the operating parameters of various devices constituting the beam generation device.

[0039] The implantation processing chamber 16 includes, in order from the upstream side of the beam line A, an energy slit 38, a plasma shower device 40, side cups 42 (42L, 42R), a profiler cup 44, and a beam stopper 46. As shown in FIG. 2, the implantation processing chamber 16 includes a platen driving device 50 that holds one or more wafers W.

[0040] The energy slit 38 is provided downstream of the angular energy filter 36, and performs energy analysis 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; Energy Defining Slit) configured as a horizontally long slit in the beam scanning direction (x direction). The energy slit 38 passes an ion beam having a desired energy value or energy range toward the wafer W, and blocks ion beams other than the desired energy value or energy range.

[0041] The plasma shower apparatus 40 is located downstream of the energy slit 38. The plasma shower apparatus 40 supplies low energy electrons to the ion beam and the surface of the wafer W (wafer processing surface) according to the beam current amount of the ion beam, and suppresses positive charge build-up on the wafer processing surface caused by 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.

[0042] The side cups 42 (42L, 42R) are configured to measure the beam current of the ion beam during ion implantation processing into the wafer W. As shown in Fig. 2, the side cups 42L, 42R are arranged shifted to the left or right (x direction) with respect to the wafer W arranged on the beamline A, and are arranged at positions where they do not block 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 part of the scanned beam is incident on the side cups 42L, 42R even during ion implantation. As a result, the beam current amount during ion implantation processing is measured by the side cups 42L, 42R.

[0043] The profiler cup 44 is a Faraday cup configured to measure the beam current at the wafer processing surface. The profiler cup 44 is configured to be movable by the operation of the profiler driving device 45, and is retracted from the implantation position where the wafer W is located during ion implantation, and is inserted into the implantation position when the wafer W is not at the implantation position. The profiler cup 44 can measure the beam current over the entire beam scanning range in the x direction by measuring the beam current while moving in the x direction. The profiler cup 44 may be formed in an array with multiple Faraday cups lined up in the x direction so that the beam current at multiple positions in the beam scanning direction (x direction) can be measured simultaneously.

[0044] At least one of the side cup 42 and the profiler cup 44 may include a single Faraday cup for measuring the amount of beam current, or may include an angle measuring device for measuring angle information of the beam. The angle measuring device may include, for example, a slit and a plurality of current detectors provided away from the slit in the beam traveling direction (z direction). The angle measuring device may measure the angle component of the beam in the slit width direction, for example, by measuring the beam that has passed through the slit with a plurality of current detectors arranged in the slit width direction. At least one of the side cup 42 and the profiler cup 44 may include a first angle measuring device capable of measuring angle information in the x direction, and a second angle measuring device capable of measuring angle information in the y direction.

[0045] The platen drive device 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. The wafer holding device 52 includes an electrostatic chuck for holding the wafer W, etc. The reciprocating motion mechanism 54 reciprocates the wafer holding device 52 in a reciprocating motion direction (y direction) perpendicular to the beam scanning direction (x direction), thereby reciprocating the wafer held by the wafer holding device 52 in the y direction. In Figure 2, the reciprocating motion of the wafer W is illustrated by arrow Y.

[0046] The twist angle adjustment mechanism 56 is a mechanism for adjusting the rotation angle of the wafer W, and adjusts the twist angle between an alignment mark provided on the outer periphery of the wafer and a reference position by rotating the wafer W around an axis that is the normal to the wafer processing surface. Here, the wafer alignment mark refers to a notch or orientation flat provided on the outer periphery of the wafer, and is a mark that serves as a reference for the crystal axis direction of the wafer and the angular position in the circumferential direction of the wafer. The twist angle adjustment mechanism 56 is provided between the wafer holding device 52 and the reciprocating mechanism 54, and is reciprocated together with the wafer holding device 52.

[0047] The tilt angle adjustment mechanism 58 is a mechanism for adjusting the inclination of the wafer W, and adjusts the tilt angle between the traveling direction of the ion beam toward the wafer processing surface and the normal to the wafer processing surface. In this embodiment, the tilt angle of the wafer W is adjusted by adjusting the angle around the x-direction axis as the central axis of rotation. The tilt angle adjustment mechanism 58 is provided between the reciprocating mechanism 54 and the inner wall of the implantation processing chamber 16, and is configured to adjust the tilt angle of the wafer W by rotating the entire platen driving device 50 including the reciprocating mechanism 54 in the R direction.

[0048] The platen driving device 50 holds the wafer W so that the wafer W can be moved between an implantation position where the wafer W is irradiated with an ion beam and a transfer position where the wafer W is loaded or unloaded between the wafer transfer device 18. Fig. 2 shows a state where the wafer W is at the implantation position, and the platen driving device 50 holds the wafer W so that the beamline A and the wafer W intersect. The transfer position of the wafer W corresponds to the position of the wafer holding device 52 when the wafer W is loaded or unloaded through the transfer port 48 by a transfer mechanism or transfer robot provided in the wafer transfer device 18.

[0049] The beam stopper 46 is provided at the most downstream of the beam line A and is attached, for example, to the inner wall of the implantation processing chamber 16. When no wafer W is present on the beam line A, the ion beam is incident on the beam stopper 46. The beam stopper 46 is located near a transfer port 48 that connects the implantation processing chamber 16 and the wafer transfer device 18, and is provided at a position vertically below the transfer port 48.

[0050] The beam stopper 46 is provided with a plurality of tuning cups 47 (47a, 47b, 47c, 47d). The plurality of tuning cups 47 are Faraday cups configured to measure the beam current of the ion beam incident on the beam stopper 46. The plurality of tuning cups 47 are arranged at intervals in the x-direction. The plurality of tuning cups 47 are used, for example, to simply measure the beam current at the implantation position without using the profiler cup 44.

[0051] The side cups 42 (42L, 42R), the profiler cup 44, and the tuning cups 47 (47a to 47d) are a beam measurement device for measuring a beam current as a physical quantity of an ion beam, or a beam detector for detecting the beam current. The side cups 42 (42L, 42R), the profiler cup 44, and the tuning cups 47 (47a to 47d) may be a beam measurement device for measuring a beam angle as a physical quantity of an ion beam, or a beam detector for detecting the beam angle.

[0052] The ion implantation apparatus 10 further includes a control device 60. The control device 60 controls the overall operation of the ion implantation apparatus 10. The control device 60 is realized in terms of hardware by elements and mechanical devices such as a computer CPU and memory, and in terms of software by a computer program or the like. Various functions provided by the control device 60 can be realized by cooperation between hardware and software.

[0053] 3 is a diagram showing a schematic example of the configuration of the control device 60. The control device 60 includes a processor 90 such as a CPU (Central Processing Unit), a memory 91 such as a ROM (Read Only Memory) or a RAM (Random Access Memory), a storage device 92 such as a HDD (Hard Disk Drive) or an SSD (Solid State Drive), and a system bus 93 connecting these. The control device 60 is connected, for example, via the system bus 93, to an input device 94 serving as a user interface such as a keyboard or a mouse, a display device 95 such as a liquid crystal display, a reading device 96 for reading a program recorded on a recording medium such as a magnetic tape, a magnetic disk, or an optical disk, and a communication interface 97 for acquiring a program by communication via a network 98.

[0054] The control device 60 controls the overall operation of the ion implantation device 10 according to a program, for example, by the processor 90 executing a program stored in the memory 91. The processor 90 may execute a program stored in the storage device 92, may execute a program acquired from a recording medium by the reading device 96, or may execute a program acquired by a communication interface 97 via a network 98. The memory 91 in which the program is stored may be a volatile memory such as a dynamic random access memory (DRAM), or may be a non-volatile memory such as an electrically erasable programmable read-only memory (EEPROM), a flash memory, a magnetoresistive memory, a resistance change memory, or a ferroelectric memory. Non-volatile memories, magnetic recording media such as magnetic tapes and magnetic disks, and optical recording media such as optical disks are examples of non-transitory and tangible computer-readable storage media.

[0055] 4 is a top view showing a schematic configuration inside implantation processing chamber 16, and shows how a beam measurement device arranged in implantation processing chamber 16 measures scan beam SB. Ion beam B is scanned back and forth in the x direction as indicated by arrow X, and is incident on wafer W as scan beam SB scanned back and forth in the x direction.

[0056] The ion beam B is scanned back and forth over a scanning range C3 including an implantation range C1 where the wafer W is located and monitor ranges C2L, C2R outside the implantation range C1. Left and right side cups 42L, 42R are disposed in the left and right monitor ranges C2L, C2R, respectively. The left and right side cups 42L, 42R can measure the ion beam B that is overscanned to the monitor ranges C2L, C2R during the implantation process.

[0057] The profiler cup 44 is retracted to a non-scanning range C4R outside the scanning range C3 during the pouring process. In the illustrated configuration, the profiler drive device 45 is disposed on the right side, and the profiler cup 44 is retracted to the non-scanning range C4R on the right side during the pouring process. Note that in a configuration in which the profiler drive device 45 is disposed on the left side, the profiler cup 44 may be retracted to the non-scanning range C4L on the left side during the pouring process.

[0058] The profiler cup 44 is placed in the implantation range C1 in a preparation step executed prior to the implantation step, and measures the beam current of the ion beam B in the implantation range C1. The profiler cup 44 measures the beam current while moving in the x direction in the implantation range C1, and measures the beam current density distribution in the x direction of the scan beam SB. The profiler cup 44 measures the beam current at the position of the wafer processing surface by moving in the x direction along a plane (measurement surface MS) that coincides with the wafer processing surface in the implantation step. The profiler cup 44 may measure the beam current density distribution in the x direction of the scan beam SB in monitor ranges C2L and C2R in addition to the implantation range C1.

[0059] The multiple tuning cups 47 are disposed in the implantation range C1 and measure the beam current of the ion beam B in the implantation range C1. The multiple tuning cups 47 are disposed at positions downstream away from the wafer W. Since the tuning cup 47 does not need to be moved between the implantation range C1 and the non-scanning range C4R as in the profiler cup 44, it is possible to measure the beam current in the implantation range C1 more simply than in the profiler cup 44.

[0060] In the preparation process, beam current measurements are taken by various Faraday cups provided in the implantation process chamber 16. Specifically, a plurality of beam current measurements are taken by using the side cups 42L, 42R, the profiler cup 44, and a plurality of tuning cups 47. The control device 60 stores the ratio between the acquired beam current measurements, and makes it possible to calculate the beam current value at the wafer processing surface from the beam current measurements taken by the side cups 42L, 42R in the implantation process. Usually, the ratio between the beam current measurements taken by the various Faraday cups depends on the setting of the beam optics of the beamline device 14, and even if the beam current of the ion beam B extracted from the ion generator 12 fluctuates to some extent, the ratio between the beam current measurements is almost constant. In other words, once the setting of the beam optics is determined in the preparation process, the ratio between the beam current measurements in the subsequent implantation process does not change. Therefore, by storing the ratio between the beam current measurement values ​​in the preparation process, the beam current value at the implantation position (i.e., the wafer processing surface) where ions are implanted into the wafer W in the implantation process can be calculated based on that ratio and the beam current measurement values ​​measured by the side cups 42L, 42R.

[0061] In the implantation process, the beam current can be constantly measured using the side cups 42L and 42R. In the implantation process, the beam current cannot be constantly measured using the profiler cup 44 or the tuning cup 47, and can only be measured intermittently. Therefore, in the implantation process, the dose of ions implanted into the wafer processing surface is controlled based on the beam current measurement value measured by the side cups 42L and 42R. If the beam current measurement value measured by the side cups 42L and 42R changes during the implantation process, the dose distribution on the wafer processing surface is adjusted by changing the wafer scan speed vw(y) in the y direction of the wafer W. For example, to achieve a uniform dose distribution within the wafer processing surface, the wafer W is reciprocated at a speed proportional to the beam current value monitored by the side cups 42L and 42R. Specifically, when the monitored beam current measurement value increases, the wafer scan speed vw(y) is increased, and when the monitored beam current value decreases, the wafer scan speed vw(y) is decreased. This makes it possible to prevent variations in the dose distribution in the wafer processing surface caused by fluctuations in the beam current of the scan beam SB.

[0062] FIG. 5 is a diagram showing a schematic data structure of an implantation recipe 70. The control device 60 controls the ion implantation process according to the implantation recipe. The implantation recipe 70 includes basic setting data 71 and detailed setting data 72. The basic setting data 71 defines implantation conditions that must be set. The basic setting data 71 includes setting data for, for example, 1) ion species, 2) beam energy, 3) beam current, 4) beam size, 5) wafer tilt angle, 6) wafer twist angle, and 7) average dose. The average dose indicates the in-plane average value of the dose distribution to be implanted into the wafer processing surface.

[0063] The detailed setting data 72 is set when performing "non-uniform implantation" in which the dose distribution of ions to be implanted in the wafer processing surface is intentionally made non-uniform. The detailed setting data 72 does not have to be set when performing "uniform implantation" in which the two-dimensional dose distribution in the wafer processing surface is a constant value. The detailed setting data 72 includes 8) two-dimensional dose distribution and 9) correction data set. The two-dimensional dose distribution is, for example, the actual value of the two-dimensional non-uniform dose distribution realized in the wafer processing surface WS when non-uniform implantation is performed. The correction data set is used to variably control the beam scanning speed in the x direction by the beam scanning unit 32 and the wafer scanning speed in the y direction by the platen driving device 50. The correction data set includes a correction function file and a correlation information file for realizing the two-dimensional non-uniform dose distribution.

[0064] 6(a) and (b) are diagrams showing a two-dimensional non-uniform dose distribution 73. FIG. 6(a) shows a two-dimensional dose distribution set non-uniformly in a circular wafer processing surface WS, and the magnitude of the dose is shown by the shading of regions 74a, 74b, 74c, and 74d in the wafer processing surface WS. In the example shown, the dose in the first region 74a is the largest, and the dose in the fourth region 74d is the smallest. The two-dimensional non-uniform dose distribution 73 is determined based on the orientation of the wafer W held by the platen driving device 50. Specifically, it is determined based on the beam scan direction (x direction) and the wafer scan direction (y direction) when the wafer W is placed on the platen driving device 50 so as to have a wafer twist angle determined in the basic setting data 71. In the example shown, the direction from the center O of the wafer W toward the alignment mark WM is the +y direction, but the position of the alignment mark WM can differ depending on the wafer twist angle.

[0065] FIG. 6(b) shows a schematic diagram of a plurality of lattice points 75 for defining a two-dimensional non-uniform dose distribution 73. The plurality of lattice points 75 are set, for example, at equal intervals on the wafer processing surface WS. The two-dimensional non-uniform dose distribution 73 is defined, for example, by data that associates the position coordinates of each of the plurality of lattice points 75 with the dose amount at each of the plurality of lattice points 75. For example, in the case of a wafer having a diameter of 300 mm, 31×31 lattice points 75 are set with the center O of the wafer processing surface WS as the origin, and the interval d1 between adjacent lattice points 75 is 10 mm. The interval d1 between the plurality of lattice points 75 is set to be smaller than the beam size of the ion beam B. An example of the beam size of the ion beam B is about 20 mm to 30 mm.

[0066] 7 is a diagram showing an example of a correction function file 77 and a correlation information file 78. The correction function file 77 defines a correction function h(x) determined based on a one-dimensional non-uniform dose distribution in the x direction. A plurality of correction function files 77 are defined for one two-dimensional non-uniform dose distribution 73, and six correction function files 77A, 77B, 77C, 77D, 77E, and 77F are defined in the illustrated example. The shapes of the correction functions h(x) of the plurality of correction function files 77A to 77F are different from each other. The number of the plurality of correction function files 77A to 77F is, for example, about 5 to 10 for one two-dimensional non-uniform dose distribution 73.

[0067] The correlation information file 78 defines correlation information that associates the two-dimensional non-uniform dose distribution 73 with a plurality of correction function files 77. The wafer processing surface WS is divided into a plurality of divided regions 76_1 to 76_31 (collectively referred to as divided regions 76) in the y direction, and each of the plurality of divided regions 76 is associated with one of a plurality of correction function files 77A to 77F. The division width d2 of the plurality of divided regions 76 in the y direction is the same as the interval d1 between the lattice points 75, and is, for example, 10 mm. The center position of each of the plurality of divided regions 76 in the y direction may correspond to the position of the lattice point 75. The division width d2 of the plurality of divided regions 76 in the y direction is set to be smaller than the beam size of the ion beam (for example, 20 mm to 30 mm).

[0068] The number of the correction function files 77 may be less than the number of the divided regions 76. Therefore, at least one correction function file 77 may be associated with the divided regions 76. In other words, a correction function h(x) defined in one correction function file 77 may be commonly used for the divided regions 76. The correction function h(x) may be normalized so that it can be used in the divided regions 76, and may be defined so that the maximum value, average value, or integral value in the first direction of the correction function h(x) is a predetermined value. The correlation information file 78 holds the ratio between the one-dimensional non-uniform dose distribution D(x) of each of the divided regions 76 and the correction function h(x) corresponding to D(x) as a correction coefficient k. The one-dimensional non-uniform dose distribution D(x) of each of the divided regions 76 corresponds to k·h(x) obtained by multiplying the correction function h(x) by the correction coefficient k. The value of the correction coefficient k tends to be large in the divided regions 76 with a relatively high dose and tends to be small in the divided regions 76 with a relatively low dose. The correction coefficient k is used to control the wafer scan speed in the y direction.

[0069] FIG. 8 is a table showing an example of the correlation information file 78. The correlation information file 78 determines the ranges in the x direction and y direction in which the wafer processing surface WS exists, the numbers A to F for identifying the correction function file 77, and the value of the correction coefficient k for each of the region numbers "1" to "31" that identify the multiple divided regions 76. Since the wafer processing surface WS is circular, the range in the x direction in which the wafer processing surface WS exists becomes smaller as it moves away from the center O of the wafer processing surface WS. For example, in the region number "1", the wafer processing surface WS exists only in a range of ±20 mm from the center O of the wafer processing surface WS, and the wafer processing surface WS does not exist in a range outside of that. On the other hand, in the region number "16" corresponding to the center O of the wafer processing surface WS, the wafer processing surface WS exists in the entire range of ±150 mm, which corresponds to the diameter of the wafer processing surface WS. In the illustrated example, the width in the y direction of each of the multiple divided regions 76 is a constant value (10 mm), but the width in the y direction of each of the multiple divided regions 76 may differ from region to region.

[0070] FIG. 9 is a schematic diagram showing a multi-step implantation. When performing a non-uniform implantation, a "multi-step implantation" may be performed in which the two-dimensional non-uniform dose distribution based on the alignment mark WM of the wafer W is fixed, and the wafer twist angle is changed to perform multiple ion implantations. When the wafer twist angle is changed, the two-dimensional non-uniform dose distribution based on the coordinate system of the ion implantation device 10 also rotates accordingly. FIG. 9 shows a case in which four ion implantations are performed by rotating the wafer twist angle by 90 degrees each. The first two-dimensional non-uniform dose distribution 73a is the same as the two-dimensional non-uniform dose distribution 73 in FIG. 6(a) described above. The second two-dimensional non-uniform dose distribution 73b is obtained by rotating the first two-dimensional non-uniform dose distribution 73a by 90 degrees clockwise. Similarly, the third two-dimensional non-uniform dose distribution 73c is obtained by rotating the second two-dimensional non-uniform dose distribution 73b by 90 degrees clockwise, and the fourth two-dimensional non-uniform dose distribution 73d is obtained by rotating the third two-dimensional non-uniform dose distribution 73c by 90 degrees clockwise. Each of the multiple two-dimensional non-uniform dose distributions 73a-73d in the multiple step implantation has a different shape when viewed from the coordinate system of the x direction and the y direction of the ion implantation apparatus 10. Therefore, in the multiple step implantation, a correction data set is determined for each of the multiple two-dimensional non-uniform dose distributions 73a-73d. When four step implantations are performed, the implantation recipe 70 includes four detailed setting data 72 corresponding to four implantation steps.

[0071] FIG. 10 is a block diagram showing a schematic functional configuration of the control device 60. The control device 60 includes an implantation control unit 61, a measurement control unit 65, a beam current matrix generating unit 66, and a storage unit 67. Each functional block shown in FIG. 10 shows a schematic representation of various functions provided by the control device 60, and indicates functions realized by a processor 90 included in the control device 60 executing a program stored in a memory 91. The boundaries of each functional block are arbitrarily determined for convenience of explanation, and boundaries other than the above-mentioned functional blocks may be determined as long as the various functions are appropriately realized. The various functions provided by the control device 60 may be realized by a single device including a processor 90 and a memory 91, or may be realized by cooperation of multiple devices each including a processor 90 and a memory 91.

[0072] The implantation control unit 61 controls the operation of the ion implantation apparatus 10 based on the implantation recipe. The implantation control unit 61 includes a beam control unit 62, a beam scanning control unit 63, and a platen control unit 64. The measurement control unit 65 controls the operation of a beam measurement device for measuring beam current, and acquires the measurement values ​​measured by the beam measurement device. The beam current matrix generation unit 66 generates a beam current matrix based on the scan signal and the measurement values ​​measured by the beam measurement device. The storage unit 67 stores the implantation recipe, operation parameters for implementing the implantation recipe, and the like.

[0073] The beam control unit 62 adjusts the operating parameters of various devices constituting the ion implantation apparatus 10 so that the implantation parameters defined in the desired implantation recipe are realized. The beam control unit 62 controls the ion species of the ion beam by adjusting the gas species and extraction voltage of the ion generation device 12, the magnetic field strength of the mass analysis unit 20, and the like. The beam control unit 62 controls the beam energy of the ion beam by adjusting the extraction voltage of the ion generation device 12, the applied voltage of the beam parallelization unit 34, the applied voltage of the AD column, the applied voltage of the angular energy filter 36, and the like. The beam control unit 62 controls the beam current of the ion beam by adjusting various parameters such as the gas amount, arc current, arc voltage, and source magnet current of the ion generation device 12, and the opening width of the mass analysis slit 23, and the like. The beam control unit 62 controls the beam size of the ion beam incident on the wafer processing surface WS by adjusting the operating parameters of the convergence / divergence device included in the beam shaping unit 30, and the like.

[0074] The beam scanning control unit 63 generates a scanning signal that determines the time waveform of the scanning command value of the beam scanning unit 32, and controls the operation of the beam scanning unit 32 based on the scanning signal. When the beam scanning unit 32 is of the electric field type, the scanning command value corresponds to the scanning voltage V applied to the scanning electrode pair of the beam scanning unit 32. When the beam scanning unit 32 is of the magnetic field type, the scanning command value corresponds to the magnet current flowing through the magnet device of the beam scanning unit 32. In this embodiment, the case where the beam scanning unit 32 is of the electric field type will be described, and the scanning command value is considered to be synonymous with the scanning voltage V, and is also expressed as the scanning command value V.

[0075] The beam scanning control unit 63 controls the beam current density distribution J(x) in the beam scanning direction (x direction) by variably controlling the beam scanning speed vb(x) realized by the beam scanning unit 32. The beam scanning speed vb(x) in the x direction is approximately proportional to the rate of change dV / dt of the scanning command value V with respect to time t. For example, in a location where a relatively high dose is required, the beam scanning control unit 63 reduces the time rate of change dV / dt of the scanning command value V so that the beam scanning speed vb(x) becomes slow. For example, in a location where a relatively low dose is required, the beam scanning control unit 63 increases the time rate of change dV / dt of the control voltage so that the beam scanning speed vb(x) becomes fast.

[0076] The beam scanning control unit 63 generates a scanning signal for realizing a target beam current density distribution based on the beam current matrix generated by the beam current matrix generating unit 66. The beam scanning control unit 63 generates a scanning signal for realizing a beam current density distribution proportional to a correction function h(x) based on, for example, a correction function h(x) defined in a correction function file 77 included in the implantation recipe and the beam current matrix. Details of the beam current matrix will be described separately later.

[0077] The platen control unit 64 generates a speed command value for specifying the reciprocating speed of the reciprocating mechanism 54, that is, the wafer scan speed vw(y) in the y direction, based on the correlation information file 78. The platen control unit 64 determines the speed command value so as to slow the wafer scan speed vw(y) in a location where a relatively high dose is required and to speed up the wafer scan speed vw(y) in a location where a relatively low dose is required. For example, the wafer scan speed vw(y) according to the position in the y direction is set to be proportional to the reciprocal 1 / k of the correction coefficient k of each of the multiple divided regions 76 defined in the correlation information file 78.

[0078] The platen control unit 64 may adjust the wafer scan speed based on the measured beam current value acquired during the implantation process. The platen control unit 64 may adjust the wafer scan speed based on the measured beam current value measured, for example, at the side cups 42L and 42R, so as to reduce the influence of fluctuations in the beam current during the implantation process.

[0079] FIG. 11 is a diagram showing a schematic diagram of a beam current matrix 80 according to an embodiment. The beam current matrix 80 has beam current values ​​Iij corresponding to an array Vi (i=1...m) of scan command values ​​V of the beam scanning unit 32 and an array Xj (j=1...n) of positions X in the x direction on the measurement surface MS that coincides with the wafer processing surface as components 82. In the example of FIG. 11, the rows (horizontal direction) of the beam current matrix 80 are the scan command values ​​Vi, and the columns (vertical direction) of the beam current matrix 80 are positions Xj in the x direction. The row components 84 of the beam current matrix 80 are beam current distributions I(Vi) corresponding to the scan command values ​​Vi when the positions Xj in the x direction are fixed to a specific position. The column components 86 of the beam current matrix 80 are beam current distributions I(Xj) corresponding to the positions Xj in the x direction when the scan command values ​​Vi are fixed to a specific value.

[0080] FIG. 12 is a diagram showing a schematic diagram of the measurement of the beam current distribution I(Vi) for the scan command value Vi, and shows a method of measuring the row components 84 of the beam current matrix 80 in FIG. 11. The beam current distribution I(Vi) for the scan command value Vi is measured in a state where the ion beam B is scanned as shown by the arrow X by changing the scan command value Vi of the beam scanning unit 32, and is obtained by measuring the beam current of the scan beam SB by the profiler cup 44 fixed at a specific measurement position Xp. The beam current distribution I(Vi) for the scan command value Vi has a distribution shape that has a peak in a range 84a centered on the specific scan command value Vp, and is 0 in ranges 84b and 84c sufficiently away from the specific scan command value Vp. Here, the specific scan command value Vp corresponds to a scan command value for deflecting the ion beam B so that it is irradiated to the specific measurement position Xp on the measurement surface MS that coincides with the wafer processing surface.

[0081] FIG. 13 is a diagram showing a schematic diagram of the measurement of the beam current distribution I(Xj) for the position Xj, and shows a method of measuring the column components 86 of the beam current matrix 80 in FIG. 11. The beam current distribution I(Xj) for the position Xj is measured in a state where the scanning command value Vi of the beam scanning unit 32 is fixed to a specific value Vp, and is obtained by measuring the beam current of the ion beam B at a plurality of measurement positions Xj by moving the profiler cup 44 as shown by the arrow X. The beam current distribution I(Xj) for the position Xj has a distribution shape that has a peak in a range 86a centered on the specific measurement position Xp, and is zero in ranges 86b and 86c sufficiently distant from the specific measurement position Xp. Here, the specific measurement position Xp corresponds to a position in the x direction where the ion beam B is irradiated on the measurement surface MS that coincides with the wafer processing surface when fixed to a specific scanning command value Vp.

[0082] Fig. 14 is a graph showing a schematic relationship between the beam current matrix I(Vi,Xj) and the beam current density distribution J(Xj). In Fig. 14, a plurality of beam current distributions Ii(Xj) with different scan command values ​​Vi are shown superimposed. The beam current density distribution J(Xj) corresponds to the sum of the plurality of beam current distributions Ii(Xj) constituting the beam current matrix I(Vi,Xj), and can be expressed by the following formula (2).

number

number

[0083] Next, a method for generating the beam current matrix I(Vi,Xj) will be described. The beam current matrix 80 in FIG. 11 is a set of a plurality of row components 84 or a set of a plurality of column components 86, and therefore can be derived by measuring either the plurality of row components 84 or the plurality of column components 86. In this embodiment, the beam current matrix 80 is derived by measuring a plurality of row components 84 from the viewpoint of measurement time. The shortest time required to measure the row components 84 at a specific measurement position Xp shown in FIG. 12 corresponds to half the round-trip scan time of the scan beam SB. When the scan period of the scan beam SB is 1 kHz, the shortest time required to measure the row components 84 at one measurement position Xj is 0.5 milliseconds. On the other hand, the shortest time required to measure the column components 86 at a specific scan command value Vp shown in FIG. 13 corresponds to the time required to move the profiler cup 44 over the implantation range C1 in FIG. 4, and is, for example, about 2 seconds.

[0084] The measurement control unit 65 acquires multiple row components 84 by measuring the beam current of the scan beam SB at multiple measurement positions while moving the profiler cup 44. The scan beam SB to be measured is scanned back and forth based on a first scan signal. The first scan signal is configured, for example, so that the beam scan speed vb(x) is constant and the time rate of change dVi / dt of the scan command value Vi is constant. Note that the first scan signal may be configured so that the beam scan speed vb(x) is not constant but is intentionally non-uniform. Note that the scan beam scanned back and forth based on the first scan signal is also referred to as the "first scan beam".

[0085] For example, the measurement control unit 65 causes the profiler cup 44 to measure the beam current of the scan beam SB at 100 measurement positions set at intervals of 3 mm in an implantation range C1 of 300 mm. When the measurement control unit 65 measures the beam current while moving the profiler cup 44, for example, the measurement control unit 65 obtains the beam current measured within a range of 3 mm, which is a position of ±1.5 mm from a certain measurement position, as the measured value of the beam current at that measurement position. When the moving speed of the profiler cup 44 is 150 mm / s, it takes 20 ms to pass the measurement positions at an interval of 3 mm. When the scan period of the scan beam SB is 1 kHz, the scan beam SB is scanned back and forth 20 times in 20 ms, so that the scan beam SB can be measured 20 times on each of the forward and backward scan paths, and a total of 40 measurements can be made in the round trip. Therefore, during the two seconds that the profiler cup 44 is moved over the 300 mm implantation range C1, the time waveform of the beam current of the scan beam SB can be measured, for example, 40 times at each of 100 measurement points, and the average value can be calculated.

[0086] FIG. 15 is a graph showing an example of the time waveform of the first scanning signal and the beam current. The upper part of FIG. 15 shows an example of the time waveform of the first scanning signal. The lower part of FIG. 15 shows the time waveform (also called the beam waveform) of the beam current measured by the profiler cup 44 when the profiler cup 44 is located at a specific measurement position Xp. The scanning beam SB crosses the profiler cup 44 at the timing of a specific scanning command value Vp corresponding to the measurement position Xp of the profiler cup 44, so that the beam waveform I(t) is measured at the timing of the specific scanning command value Vp. The time width tw of one beam waveform I(t) corresponds to the time for the spot-shaped ion beam B to be scanned to pass through the measurement width (slit width) of the profiler cup 44. For example, when the measurement width in the x direction of the profiler cup 44 is 5 mm, the spot size in the x direction of the ion beam B is 15 mm, and the scanning speed in the x direction of the ion beam B is 800 m / s, the time width tw of one beam waveform is 25 μs. The circles in the lower part of Fig. 15 indicate the sampling timing of the beam current measurement. The sampling frequency of the beam current measurement is, for example, 0.5 MHz. In the example of Fig. 15, the time width tw of 25 μs is sampled every 2 μs, so one beam waveform I(t) is composed of 13 sampling values.

[0087] The various parameters related to the measurement of the scan beam SB are not limited to the above-mentioned numerical values, and any other numerical values ​​may be adopted. The frequency of the scan beam SB is selected from the range of 0.1 Hz to 10 kHz, for example, from the range of 1 Hz to 5 kHz. The implantation range C1 is selected from the range of 100 mm to 1000 mm, for example, from the range of 150 mm to 450 mm, preferably from the range of 200 mm to 300 mm. The implantation range C1 may be selected based on the diameter of the wafer W, for example. The moving speed of the profiler cup 44 is selected from the range of 50 mm / s to 500 mm / s, for example, from the range of 100 mm / s to 300 mm / s. The interval between the measurement positions is selected from the range of 0.5 mm to 100 mm, for example, from the range of 1 mm to 10 mm. The spot size of the ion beam B is selected from the range of 5 mm to 500 mm, for example, from the range of 10 mm to 300 mm, preferably from the range of 20 mm to 200 mm. The measurement width of the profiler cup 44 is selected from the range of 1 mm to 30 mm, for example, from the range of 5 mm to 10 mm. The sampling frequency of the beam current is selected from the range of 10 kHz to 10 MHz, for example, from the range of 0.1 MHz to 1 MHz.

[0088] The measurement control unit 65 may move the profiler cup 44 back and forth over the implantation range C1 such that the measurement positions of the beam current are different on the outward and return paths of the reciprocating movement. For example, the profiler cup 44 may measure the time waveform of the beam current at a plurality of first measurement positions on the outward path of the reciprocating movement, and measure the time waveform of the beam current at a plurality of second measurement positions on the return path of the reciprocating movement. The plurality of first measurement positions and the plurality of second measurement positions may be set to be alternately positioned in the x direction.

[0089] The measurement control unit 65 may correct the time waveform of the beam current based on a parameter related to the beam current measurement of the beam measurement device. The measurement control unit 65 may correct the beam waveform based on the measurement width in the x direction of the beam measurement device. A beam measurement device such as the profiler cup 44 measures the average value of the beam current over the measurement width (slit width) in the x direction. Therefore, the time width tw of one beam waveform measured by the profiler cup 44 is larger than the time width of the true beam waveform corresponding to the actual spot size of the ion beam B. In the example of FIG. 15, the time width tw of the beam waveform measured by the profiler cup 44 for the ion beam B with a spot size of 15 mm is 25 μs, but the time width of the true beam waveform is 19 μs.

[0090] The measurement control unit 65 may derive a time waveform corresponding to the true beam waveform by, for example, correcting the time waveform of the beam current using the relationship that the measured value of the beam waveform is composed of a smoothed component of the true beam waveform. The measurement control unit 65 may derive a time waveform corresponding to the true beam waveform by correcting the time waveform of the beam current so as to narrow the time width tw of the measured value of the beam waveform.

[0091] The measurement control unit 65 may correct the time waveform of the beam current based on a time constant τ=CR of a low-pass filter included in the beam current measurement circuit. FIG. 16 is a circuit diagram showing an example of the configuration of the beam current measurement circuit 100. The beam current measurement circuit 100 includes a shunt resistor 102, a filter circuit 104, an amplifier circuit 106, and an A / D (Analog to Digital) conversion circuit 108. The shunt resistor 102 converts the beam current Iin of the ion beam incident on the profiler cup 44 into an input voltage Vin. If the resistance value of the shunt resistor 102 is Rs, then Vin=Rs·Iin. The filter circuit 104 is a low-pass filter (LPF) using a resistor R and a capacitor C, and generates an output voltage Vout by smoothing the input voltage Vin. The relationship between the input voltage Vin and the output voltage Vout of the filter circuit 104 is expressed as Vin=Vout+CR(dVout / dt). The amplifier circuit 106 is a voltage amplifier circuit composed of an operational amplifier and resistors R1 to R4, and outputs a voltage β·Vout obtained by amplifying the output voltage Vout of the filter circuit 104 by a predetermined amplification factor β. The A / D conversion circuit 108 samples the output voltage β·Vout of the amplifier circuit 106 to generate a digital value. The measurement control unit 65 obtains the digital value output from the A / D conversion circuit 108 as a measurement value of the beam current.

[0092] The measured value of the beam current acquired by the measurement control unit 65 is proportional to the output voltage Vout of the filter circuit 104, and therefore is not proportional to the true beam waveform Iin(t) measured in the profiler cup 44. The measurement control unit 65 may derive a time waveform equivalent to the true beam waveform Iin(t) by calculating Vin from Vout based on the relational equation Vin=Vout+CR(dVout / dt) using the time constant τ=CR of the filter circuit 104.

[0093] The measurement control unit 65 further calculates the beam current density distribution in the x direction of the first scan beam by time-integrating the beam current measured by the beam measurement device for each measurement position Xj. The actual value of the beam current density distribution of the first scan beam is also referred to as the "first beam current density distribution J1(Xj)". For example, the measurement control unit 65 calculates the actual value J1(Xp) of the first beam current density at a specific measurement position Xp by time-integrating the beam waveform shown in the lower part of FIG. 15 and calculating the area occupied by the beam waveform. The measurement control unit 65 acquires the beam waveform I(t) by sampling and measuring the time waveform of the beam current measured by the profiler cup 44, and at the same time calculates the actual value J1(Xj) of the first beam current density distribution by time-integrating the time waveform of the beam current.

[0094] The beam current matrix generator 66 calculates a beam current matrix based on the time waveform I(t) of the beam current at multiple measurement positions and the time waveform V(t) of the scan command value defined in the first scan signal. The beam current matrix generator 66 converts the time waveform I(t) of the beam current into a beam current distribution I(Vi) for the scan command value Vi based on the time waveform V(t) of the scan command value, and calculates the beam current distribution I(Vi) at multiple measurement positions. This makes it possible to calculate a beam current matrix whose components are beam current values ​​I(Xj,Vi)=Iij for multiple positions Xj and multiple scan command values ​​Vi.

[0095] The beam current matrix generating unit 66 may calculate beam current value components Iij=I(Xd,Vj) for a plurality of supplementary positions Xd different from the plurality of measurement positions Xc based on beam current value components Iij=I(Xc,Vj) for a plurality of measurement positions Xc. The beam current matrix generating unit 66 may calculate beam current value components Iij=I(Xd,Vj) for a supplementary position Xd located between two adjacent measurement positions Xc1 and Xc2 by, for example, interpolation. The beam current matrix generating unit 66 may calculate beam current value components Iij=I(Xd,Vj) for a supplementary position Xd located outside the plurality of measurement positions Xc by extrapolation. The number of the plurality of supplementary positions Xd may be approximately the same as the number of the plurality of measurement positions Xc, or may be greater than the number of the plurality of measurement positions Xc. The number of the plurality of supplementary positions Xd may be approximately two to five times the number of the plurality of measurement positions Xc.

[0096] The beam current matrix generating unit 66 corrects the value of each component Iij of the calculated beam current matrix based on the measured value J1(Xj) of the first beam current density distribution to determine each component I'ij of the corrected beam current matrix. Each component I'ij of the corrected beam current matrix is ​​obtained by multiplying each component Iij of the beam current matrix before correction by the correction matrix αij, and can be expressed as I'ij=αij·Iij. The correction matrix αij is determined so that the calculated value J'(Xj) of the beam current density distribution based on the corrected beam current matrix I'ij matches the measured value J1(Xj) of the first beam current density distribution. The calculated value J'(Xj) of the beam current density distribution based on the corrected beam current matrix I'ij is expressed by the following formula (4) using the dwell time Δt1i of the first scan beam at the scan command value Vi determined in the first scan signal.

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[0097] FIG. 17 is a graph showing an example of a calculated value J(Xj) of a beam current density distribution based on a beam current matrix Iij before correction and a scan command value Vi defined in a first scan signal, and an actual value J1(Xj) of the beam current density distribution. The vertical axis of the graph indicates current intensity, which is normalized by setting the overall average value of the beam current density distribution to 1. The calculated value J(Xj) and the actual value J1(Xj) are roughly consistent, but there is a deviation between the two within a range of about ±2% depending on the position Xj. In order to make the calculated value J(Xj) and the actual value J1(Xj) coincide with each other, a correction coefficient α(Xj) depending on the position Xj can be defined, and can be expressed as α(Xj)=J1(Xj) / J(Xj). The correction matrix αij is a diagonal matrix with the correction coefficient α(Xj) as a diagonal element.

[0098] Next, a method for generating a scan signal based on a beam current matrix will be described. The beam scanning control unit 63 generates a scan signal based on a target beam current density distribution Jt(Xj) and a corrected beam current matrix I'ij generated by a beam current matrix generating unit 66. Here, a scan signal for realizing a target beam current density distribution Jt(Xj) is also called a "second scan signal." The beam scanning control unit 63 calculates a beam dwell time Δt2i that satisfies the relationship of the following equation (6).

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[0099] The beam scanning control unit 63 can calculate the dwell time Δt2i of the scan beam at the scan command value Vi by using an optimization calculation method. For example, the beam dwell time Δt2i can be calculated by optimization calculation based on a first evaluation value for evaluating the difference between the target beam current density distribution Jt(Xj) and the beam current density distribution J'(Xj) calculated based on the corrected beam current matrix I'ij and the beam dwell time Δt2i. For example, the sum of square errors between the target value Jt(Xj) and the calculated value J'(Xj) expressed by the following formula (7) can be used as the first evaluation value E1.

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[0100] The beam scanning control unit 63 may perform optimization calculation by combining a plurality of evaluation values. The beam scanning control unit 63 may further use a second evaluation value for evaluating the amount of change in the time rate of change dVi / dt of the scan command value Vi in the second scanning signal. The second evaluation value E2 can be defined as, for example, the sum of squares of the amount of change in the beam dwell time Δt2i, and can be expressed by the following formula (8).

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[0101] The beam scan control unit 63 may further use a third evaluation value for evaluating the amount of beam current irradiated to a part of the scanning range C3 of the ion beam B. The third evaluation value E3 can be defined as the sum of squares of the calculated value J'(Xj) of the beam current density distribution where the position Xj is in a specific range (for example, Xa≦Xj≦Xb), and can be expressed by the following formula (9).

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[0102] The beam scan control unit 63 may generate a plurality of second scan signals based on the corrected beam current matrix I'ij. The plurality of second scan signals are generated to realize a plurality of target beam current density distributions. The plurality of target beam current density distributions correspond to a plurality of correction functions h(x) for performing two-dimensional non-uniform implantation, for example.

[0103] The beam scanning control unit 63 controls the operation of the beam scanning unit 32 based on the generated second scanning signal to generate a second scanning beam. The measurement control unit 65 measures the beam current of the second scanning beam using a beam measurement device. The measurement control unit 65 calculates the actual measurement value J2(Xj) of the second current density distribution of the second scanning beam, for example, by time integrating the measurement value of the beam current by the profiler cup 44. The beam scanning control unit 63 compares the actual measurement value J2(Xj) of the second current density distribution with the target beam current density distribution Jt(Xj) to evaluate the validity of the second scanning signal. For example, if the difference between the actual measurement value J2(Xj) and the target value Jt(Xj) is within a predetermined range, the beam scanning control unit 63 determines that the second scanning signal is valid, and if the difference is outside the predetermined range, the beam scanning control unit 61 determines that the second scanning signal is not valid. If the second scanning signal is valid, the implantation control unit 61 irradiates the wafer W with the second scanning beam based on the second scanning signal to perform an ion implantation process.

[0104] The measurement control unit 65 may measure the beam current of the second scan beam using a beam measurement device other than the profiler cup 44, instead of using the profiler cup 44. The measurement control unit 65 may measure the second current density distribution J2(Xj) of the second scan beam using a beam measurement device other than the beam measurement device used to measure the first scan beam. The measurement control unit 65 may measure the second current density distribution J2(Xj) of the second scan beam using multiple tuning cups 47a to 47d. When multiple tuning cups 47a to 47d are used, it is not necessary to move the profiler cup 44 in the x direction, so that the second current density distribution J2(Xj) can be measured more quickly and simply than when the profiler cup 44 is used. The beam scanning control unit 63 may evaluate the validity of the second scan signal based on the actual value J2(Xj) of the second current density distribution measured by the multiple tuning cups 47a to 47d.

[0105] When the beam scanning control unit 63 determines that the second scanning signal is not appropriate, the beam scanning control unit 63 may regenerate the second scanning signal so that the target beam current density distribution Jt(Xj) is realized. The beam scanning control unit 63 may regenerate the second scanning signal by changing the target value, instead of using the target beam current density distribution Jt(Xj) as the target value as it is. For example, the second scanning signal may be regenerated using a new target value Ju(Xj)=Jt(Xj)+m·ΔJ(Xj) obtained by adding a difference value ΔJ(Xj)=Jt(Xj)-J2(Xj) between the actual measurement value J2(Xj) of the second current density distribution of the second scanning beam and the target value Jt(Xj) to the initial target value. Here, m is a coefficient having a positive value and adjusting the weighting of the difference value ΔJ(Xj).

[0106] The beam current matrix generating unit 66 may regenerate the corrected beam current matrix I'ij when the second scan signal generated or regenerated by the beam scanning control unit 63 is not valid. For example, when beam conditions such as the beam current or beam size of the ion beam B have changed, the measurement control unit 65 may remeasure the first scan beam based on the first scan signal, and the beam current matrix generating unit 66 may regenerate the corrected beam current matrix I'ij based on the remeasurement result.

[0107] The beam control unit 62 may estimate the beam shape of the spot-shaped ion beam B in the x direction based on the corrected beam current matrix I'ij, and adjust the beam shape of the ion beam B based on the estimated beam shape. The column components 86 of the beam current matrix 80 shown in Fig. 11 are beam current distribution I(Xj) for the position Xj in the x direction when the scan command value Vi is fixed to a specific value, and therefore may be said to represent the beam shape of the unscanned ion beam B. For example, by regarding the column components I'0(Xj) of the corrected beam current matrix at the scan command value Vi=0 as the beam shape of the ion beam B, the beam control unit 62 may adjust the beam size, etc. based on the column components I'0(Xj).

[0108] According to this embodiment, by generating a second scan signal for realizing a target beam current density distribution Jt(Xj) based on the corrected beam current matrix I'ij, it is possible to generate a valid second scan signal in a short time and with high accuracy compared to the conventional method. In the conventional method, there are cases where a valid second scan signal cannot be generated by one calculation process, and a valid second scan signal cannot be generated unless a plurality of calculation processes are performed while repeatedly measuring the beam current density distribution. In addition, when the shape of the target beam current density distribution Jt(Xj) is complex, the conventional method may fail to generate a valid second scan signal even if a plurality of calculation processes are performed while repeatedly measuring the beam current density distribution. On the other hand, according to this embodiment, even in cases where the conventional method fails, a valid second scan signal can be generated by a small number of calculation processes, such as one or two. As a result, the work time for generating a second scan signal in the preparation process before the implantation process can be shortened, and the productivity in the ion implantation process can be improved. In particular, in a case where a plurality of second scan signals must be generated for non-uniform implantation, the work time required for the preparation process can be significantly shortened.

[0109] Next, a description will be given of an ion implantation method using the above-mentioned ion implantation apparatus 10. Here, an object to be irradiated with the ion beam B is a semiconductor wafer W, and an ion implantation step included in a method for manufacturing a semiconductor device will be described.

[0110] FIG. 18 is a flow chart showing an example of an ion implantation method according to an embodiment. The beam scanning control unit 63 operates the beam scanning unit 32 based on the first scanning signal, and generates a first scanning beam by scanning the spot-shaped ion beam B back and forth in a predetermined direction (x direction) (S10). The measurement control unit 65 measures the beam current of the first scanning beam at a plurality of different measurement positions in the predetermined direction (x direction) using a beam measurement device (S12). The beam current matrix generation unit 66 calculates a beam current matrix having beam current values ​​for a plurality of different positions in the predetermined direction (x direction) and a plurality of scanning command values ​​as components based on the time waveform of the beam current measured by the beam measurement device and the time waveform of the scanning command value determined in the first scanning signal (S14). The measurement control unit 65 calculates a first beam current density distribution in the predetermined direction (x direction) of the first scanning beam by integrating the measured beam current over time (S16). The beam current matrix generating unit 66 corrects the value of each component of the beam current matrix based on the first beam current density distribution to generate a corrected beam current matrix (S18). The beam scanning control unit 63 generates a second scanning signal for realizing a target beam current density distribution based on the corrected beam current matrix (S20). The beam scanning control unit 63 operates the beam scanning unit 32 based on the second scanning signal to generate a second scanning beam by scanning the spot-shaped ion beam B back and forth in a predetermined direction (x direction) (S22). The implantation control unit 61 performs an ion implantation process by irradiating the semiconductor wafer with the second scanning beam (S24).

[0111] Although the present disclosure has been described above with reference to the above-mentioned embodiments, the present disclosure is not limited to the above-mentioned embodiments, and the configurations of the embodiments may be appropriately combined or substituted. In addition, it is possible to appropriately rearrange the combinations and processing orders in the embodiments based on the knowledge of a person skilled in the art, and to add modifications such as various design changes to the embodiments, and the embodiments to which such rearrangements and modifications have been made may also be included in the scope of the ion implantation apparatus, ion implantation method, and semiconductor device manufacturing method according to the present disclosure.

[0112] The embodiments of the present disclosure may take the form of a computer program comprising one or more computer readable sequences describing the methods of the present disclosure, or a non-transitory tangible recording medium having such a computer program stored thereon (e.g., a non-volatile memory, a magnetic tape, a magnetic disk, or an optical disk). A processor may execute such a computer program to implement the methods of the present disclosure. [Explanation of symbols]

[0113] 10... ion implantation device, 12... ion generation device, 14... beam line device, 16... implantation processing chamber, 18... wafer transport device, 32... beam scanning unit, 34... beam collimation unit, 60... control device, 61... implantation control unit, 62... beam control unit, 63... beam scanning control unit, 64... platen control unit, 65... measurement control unit, 66... ​​beam current matrix generation unit, 80... beam current matrix, B... ion beam, W... wafer.

Claims

1. generating a first scan beam by scanning the spot-shaped ion beam back and forth in a predetermined direction based on a first scan signal; measuring a beam current of the first scanning beam at a plurality of different measurement positions in the predetermined direction using a beam measurement device; calculating a beam current matrix having beam current values ​​corresponding to a plurality of different positions and a plurality of different scan command values ​​in the predetermined direction as components based on a time waveform of the beam current measured by the beam measurement device and a time waveform of a scan command value defined in the first scan signal; calculating a first beam current density distribution in the predetermined direction of the first scanning beam by integrating the measured beam current with respect to time; correcting a value of each component of the beam current matrix based on the first beam current density distribution; generating a second scanning signal for realizing a target beam current density distribution based on the corrected beam current matrix.

2. correcting a time waveform of the beam current based on a parameter related to beam current measurement of the beam measurement device, 2. The ion implantation method according to claim 1, wherein the beam current matrix is ​​calculated based on a time waveform of the corrected beam current.

3. 3. The ion implantation method according to claim 2, wherein the time waveform of the beam current is corrected based on a measurement width in the predetermined direction of the beam measurement device.

4. 4. The ion implantation method according to claim 2, wherein the time waveform of the beam current is corrected based on a time constant of a beam current measuring circuit of the beam measuring device.

5. 5. The ion implantation method according to claim 1, wherein the beam current is measured at the plurality of measurement positions by moving the beam measurement device in the predetermined direction.

6. 6. The ion implantation method according to claim 1, wherein the beam measurement device includes a plurality of Faraday cups arranged at different positions in the predetermined direction.

7. The beam measurement device may be moved back and forth in the predetermined direction. the plurality of measurement locations include a plurality of first measurement locations and a plurality of second measurement locations; 7. The ion implantation method according to claim 5, wherein the beam current is measured at the plurality of first measurement positions on the outward path of the reciprocating movement, and is measured at the plurality of second measurement positions on the return path of the reciprocating movement.

8. 8. The ion implantation method according to claim 1, wherein calculating the beam current matrix includes calculating components of beam current values ​​for a plurality of capture positions different from the plurality of measurement positions based on components of beam current values ​​for the plurality of measurement positions.

9. 9. The ion implantation method according to claim 1, wherein calculating the beam current matrix includes converting a time waveform of the beam current into a waveform of the beam current for a scan command value based on a time waveform of the scan command value defined in the first scan signal.

10. 10. The ion implantation method according to claim 1, wherein the first scanning signal has a non-uniform time rate of change of the scanning command value.

11. 11. The ion implantation method according to claim 1, wherein the second scanning signal is generated based on a first evaluation value for evaluating a difference between a beam current density distribution calculated based on the corrected beam current matrix and the second scanning signal and a target beam current density distribution.

12. 12. The ion implantation method according to claim 11, wherein the second scanning signal is generated further based on a second evaluation value for evaluating an amount of change in a time rate of the scanning command value in the second scanning signal.

13. 13. The ion implantation method according to claim 11, wherein the second scanning signal is generated further based on a third evaluation value for evaluating an amount of beam current irradiated to a portion of the scanning range of the ion beam in the specified direction.

14. generating a second scan beam by scanning the ion beam back and forth in the predetermined direction based on the second scan signal; 14. The ion implantation method according to claim 1, further comprising: irradiating a semiconductor wafer with the second scanning beam.

15. generating the second scan signal includes generating a plurality of second scan signals for realizing a plurality of target beam current density distributions based on the corrected beam current matrix; generating the second scan beam includes sequentially generating a plurality of second scan beams corresponding to the plurality of second scan signals; 15. The ion implantation method of claim 14, wherein irradiating the semiconductor wafer with the second scan beam includes irradiating each of a plurality of regions on the semiconductor wafer divided in a direction perpendicular to the specified direction with any one of the plurality of second scan beams.

16. measuring the second scanned beam to calculate a second beam current density distribution; 16. The method of claim 14 or 15, further comprising: comparing the second beam current density distribution with the target beam current density distribution.

17. 17. The ion implantation method according to claim 16, wherein the calculated second beam current density distribution is measured using a beam measurement device different from the beam measurement device used to measure the first scan beam.

18. The ion implantation method according to claim 16 or 17, characterized in that the second scanning signal is regenerated based on the calculated second beam current density distribution, the target beam current density distribution, and the corrected beam current matrix.

19. estimating a beam shape of the ion beam based on the corrected beam current matrix; 19. The ion implantation method according to claim 1, further comprising: adjusting a beam shape of the ion beam based on the estimated beam shape.

20. a beam scanning device that generates a first scan beam by scanning a spot-shaped ion beam back and forth in a predetermined direction based on a first scan signal; a beam measurement device configured to measure a beam current of the first scanning beam at a plurality of different measurement positions in the predetermined direction; a control device that generates a scanning signal that determines a time waveform of a scanning command value corresponding to a scanning position in the predetermined direction based on the measurement by the beam measurement device, The control device includes: acquiring a time waveform of the beam current of the first scan beam measured at the plurality of measurement positions; calculating a beam current matrix having components of beam current values ​​corresponding to the position in the predetermined direction and the scan command value based on a time waveform of the acquired beam current and a time waveform of a scan command value defined in the first scan signal; calculating a first beam current density distribution in the predetermined direction of the first scanning beam by integrating the acquired beam current with respect to time; correcting values ​​of each component of the beam current matrix based on the first beam current density distribution; and generating a second scanning signal for achieving a target beam current density distribution based on the corrected beam current matrix.

21. 21. The ion implantation apparatus according to claim 20, wherein the control device is configured to convert the time waveform of the beam current into a waveform of the beam current for the scan command value based on the time waveform of the scan command value defined in the first scan signal.

22. the beam scanning device generates a second scan beam by scanning the ion beam back and forth in the predetermined direction based on the second scan signal; 22. The ion implantation apparatus according to claim 20, wherein the ion implantation apparatus irradiates the second scan beam onto a semiconductor wafer.

23. the control device is configured to generate a plurality of second scan signals for realizing a plurality of target beam current density distributions based on the corrected beam current matrix; the beam scanning device sequentially generates a plurality of second scan beams corresponding to the plurality of second scan signals by reciprocally scanning the ion beam in the predetermined direction based on each of the plurality of second scan signals; 23. The ion implantation apparatus according to claim 22, wherein the ion implantation apparatus irradiates each of a plurality of regions on the semiconductor wafer divided in a direction perpendicular to the predetermined direction with any one of the plurality of second scan beams.

24. A method for manufacturing a semiconductor device comprising an ion implantation step, the ion implantation step comprising: generating a first scan beam by scanning the spot-shaped ion beam back and forth in a predetermined direction based on a first scan signal; Measuring a beam current of the first scan beam at a plurality of different measurement positions in the predetermined direction; calculating a beam current matrix having beam current values ​​corresponding to a plurality of different positions and a plurality of different scan command values ​​in the predetermined direction as components based on a time waveform of the measured beam current and a time waveform of a scan command value determined in the first scan signal; calculating a first beam current density distribution in the predetermined direction of the first scanning beam by integrating the measured beam current with respect to time; correcting a value of each component of the beam current matrix based on the first beam current density distribution; generating a second scanning signal for realizing a target beam current density distribution based on the corrected beam current matrix; generating a second scan beam by scanning the ion beam back and forth in the predetermined direction based on the second scan signal; and irradiating the second scanning beam onto a semiconductor wafer.

25. 25. The method for manufacturing a semiconductor device according to claim 24, wherein calculating the beam current matrix includes converting a time waveform of the beam current into a waveform of the beam current for the scan command value based on a time waveform of the scan command value defined in the first scan signal.

26. generating the second scan signal includes generating a plurality of second scan signals for realizing a plurality of target beam current density distributions based on the corrected beam current matrix; generating the second scan beam includes sequentially generating a plurality of second scan beams corresponding to the plurality of second scan signals; 26. The method for manufacturing a semiconductor device according to claim 24 or 25, wherein irradiating the semiconductor wafer with the second scan beam includes irradiating each of a plurality of regions on the semiconductor wafer divided in a direction perpendicular to the specified direction with any one of the plurality of second scan beams.

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