Ion implantation device and model generation method

Abstract

The present invention evaluates the validity of the measurement of a physical quantity of an ion beam. An ion implantation apparatus (10) comprises: a beam generating apparatus for generating an ion beam according to an implantation recipe; a plurality of measuring apparatuses for measuring at least one physical quantity of the ion beam; and a control apparatus (60) for acquiring a data set including a plurality of measurement values ​​measured by the plurality of measuring apparatuses and evaluating the validity of the measurement of the at least one physical quantity of the ion beam using a model representing the correlation between the plurality of measurement values.

Description

Technical Field

[0001] This application claims the benefit of priority based on Japanese Patent Application No. 2020-036546, filed on March 4, 2020. The entire contents of this Japanese patent application are incorporated herein by reference.

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

[0003] In the semiconductor manufacturing process, a process of implanting ions into a semiconductor wafer (also known as an ion implantation process) is routinely performed to alter the semiconductor's conductivity, crystal structure, and other properties. The apparatus used in the ion implantation process is called an ion implantation apparatus. The ion implantation apparatus is configured to measure physical quantities such as the beam current and beam angle of the ion beam to be irradiated onto the wafer, and adjust the ion beam based on the measured values ​​to achieve the required ion implantation accuracy under the desired implantation conditions (for example, see Patent Document 1).

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 9-82266

[0005] To improve implant accuracy, one approach is to use a high-precision measurement device. However, if the measurement itself contains some anomalies, even this highly accurate device may not be able to accurately measure the implant. In this case, beam adjustment and implant processing may be performed based on inaccurate measurement values, potentially failing to achieve the required implant accuracy. Summary of the Invention

[0006] One exemplary object of an embodiment of the present invention is to provide a technique for evaluating the validity of a measurement of a physical quantity.

[0007] An ion implantation apparatus according to one embodiment of the present invention comprises: a beam generating apparatus for generating an ion beam according to an implantation recipe; a plurality of measuring apparatuses for measuring at least one physical quantity of the ion beam; and a control apparatus for acquiring a data set comprising a plurality of measurement values ​​measured by the plurality of measuring apparatuses, and evaluating the appropriateness of the measurement of at least one physical quantity of the ion beam using a model representing the correlation between the plurality of measurement values.

[0008] Another embodiment of the present invention is a model generation method. The method includes the steps of acquiring a data set containing a plurality of measurement values ​​representing at least one physical quantity of the ion beam from a plurality of measurement devices that measure ion beams generated according to an implantation recipe; and constructing a model representing correlations between the plurality of measurement values ​​based on the plurality of data sets acquired during a plurality of implantation steps based on the implantation recipe.

[0009] Furthermore, any combination of the above-mentioned constituent elements or constituent elements or expressed contents of the present invention may be replaced with each other among methods, apparatuses, systems, etc., and these may also be effective as embodiments of the present invention.

[0010] Effects of the Invention

[0011] According to the present invention, the validity of the measurement of the physical quantity of the ion beam can be evaluated. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0014] Figure 3 It is a plan view schematically showing the structure inside the implantation processing chamber.

[0015] Figure 4 It is a block diagram schematically showing the functional structure of the control device.

[0016] Figure 5 Schematically shows a function showing the correlation between a plurality of measurement value vectors.

[0017] Figure 6 This is a diagram schematically showing a plurality of threshold values ​​set for the model.

[0018] Figure 7 This is a graph schematically showing a method of correcting a measurement value vector.

[0019] Figure 8 This is a flowchart schematically showing the flow of the ion implantation method according to the embodiment.

[0020] In the figure: 10-ion implantation device, 12-ion generation device, 14-beam line device, 16-implantation processing chamber, 42-side cup, 44-contour cup, 47-adjustment cup, 60-control device, 61-implantation control unit, 62-implantation process acquisition unit, 63-beam adjustment unit, 64-dose control unit, 65-measurement management unit, 66-data set acquisition unit, 67-measurement evaluation unit, 68-measurement correction unit, 69-model construction unit, 70-storage unit, B-ion beam, W-wafer. DETAILED DESCRIPTION

[0021] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the accompanying drawings, identical elements are denoted by identical reference numerals, and repeated descriptions are omitted as appropriate. Furthermore, the structures described below are merely examples and do not limit the scope of the present invention in any way.

[0022] Before describing the embodiment in detail, an overview is provided. The ion implantation apparatus according to the present embodiment generates an ion beam according to a desired implantation recipe, and measures at least one physical quantity of the ion beam using a plurality of measuring devices. The plurality of measuring devices are arranged at various locations within the ion implantation apparatus, and are configured to measure the beam current as an example of a physical quantity. The plurality of measuring devices measure the same ion beam. Therefore, as long as the measurement of each measuring device itself is normal, it is assumed that the plurality of measurement values ​​measured by the plurality of measuring devices have a certain correlation such as a proportional relationship. Assuming that an abnormality occurs in the measurement based on any one of the measuring devices, it is expected that the correlation between the plurality of measurement values ​​is destroyed.

[0023] Therefore, in this embodiment, a model representing the correlation between multiple measurement values ​​under normal conditions is pre-constructed, and the correlation between multiple measurement values ​​during any implantation is evaluated based on this model. For example, the degree to which the correlation between multiple measurement values ​​during implantation deviates from the model serving as the benchmark is calculated, and the validity of the measurement is evaluated based on this deviation. This makes it possible to detect measurement errors caused by abnormalities in the measurement itself. In addition, by correcting the measurement values ​​based on the model, beam adjustment or dose control, etc., can be performed based on the more accurate corrected measurement values. This makes it possible to achieve the very strict implantation accuracy required in recent years, and to improve the reliability of the ion implantation process.

[0024] Figure 1 FIG. 1 is a plan view schematically showing an ion implantation apparatus 10 according to an embodiment. Figure 2 1 is a side view schematically illustrating the structure of an ion implantation apparatus 10. The ion implantation apparatus 10 is configured to perform ion implantation on the surface of an object W. The object W is, for example, a substrate, such as a semiconductor wafer. For ease of explanation, the object W may sometimes be referred to as a wafer W in this specification, but this is not intended to limit the implantation target to a specific object.

[0025] The ion implantation apparatus 10 is configured to scan the beam back and forth in one direction, causing the wafer W to reciprocate in a direction perpendicular to the scanning direction, thereby irradiating the entire processing surface of the wafer W with the ion beam. In this specification, for ease of explanation, the direction of travel of the ion beam traveling along the designed beam line A is defined as the z direction, and the surface perpendicular to the z direction is defined as the xy surface. When the ion beam is scanned on the object W to be processed, 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 reciprocating scanning of the beam is performed in the x direction, and the reciprocating motion of the wafer W is performed in the y direction.

[0026] The ion implantation apparatus 10 includes an ion generating apparatus 12, a beamline apparatus 14, an implantation processing chamber 16, and a wafer conveying apparatus 18. The ion generating apparatus 12 is configured to provide an ion beam to the beamline apparatus 14. The beamline apparatus 14 is configured to convey an ion beam from the ion generating apparatus 12 to the implantation processing chamber 16. The implantation processing chamber 16 accommodates a wafer W to be implanted, and an implantation process is performed by irradiating the wafer W with the ion beam provided from the beamline apparatus 14. The wafer conveying apparatus 18 is configured to carry an untreated wafer before implantation processing into the implantation processing chamber 16 and to carry a processed wafer after implantation processing out of the implantation processing chamber 16. The ion implantation apparatus 10 includes a vacuum exhaust system (not shown) for providing a desired vacuum environment to the ion generating apparatus 12, the beamline apparatus 14, the implantation processing chamber 16, and the wafer conveying apparatus 18.

[0027] The beamline apparatus 14 includes, in order from the upstream side of beamline A, a mass spectrometer 20, a beam stopping device 24, a beam shaper 30, a beam scanner 32, a beam collimator 34, and an angular energy filter (AEF) 36. The upstream side of beamline A refers to the side closer to the ion generator 12, and the downstream side of beamline A refers to the side closer to the implantation chamber 16 (or beam stopper 46).

[0028] The mass spectrometer 20 is provided downstream of the ion generator 12 and is configured to select desired ion species from the ion beam extracted from the ion generator 12 by mass spectrometry. The mass spectrometer 20 includes a mass spectrometer magnet 21 , a mass spectrometer lens 22 , and a mass spectrometer slit 23 .

[0029] The mass spectrometry magnet 21 applies a magnetic field to the ion beam extracted from the ion generating device 12, and deflects the ion beam along different paths according to the value of the mass-to-charge ratio M=m / q (m is mass, q is charge). For example, the mass spectrometry magnet 21 applies a magnetic field to the ion beam in the y direction (in Figure 1 and Figure 2 The magnetic field strength of the mass spectrometry magnet 21 is adjusted so that ion species with a desired mass-to-charge ratio M pass through the mass spectrometry slit 23.

[0030] The mass spectrometer lens 22 is located downstream of the mass spectrometer magnet 21 and is configured to adjust the convergence / divergence force on the ion beam. The mass spectrometer lens 22 adjusts the convergence position of the ion beam in the beam travel direction (z direction) passing through the mass spectrometer slit 23 and adjusts the mass resolution M / dM of the mass spectrometer 20. The mass spectrometer lens 22 is not a required component and can be omitted from the mass spectrometer 20.

[0031] The mass analysis slit 23 is provided downstream of the mass analysis lens 22 and at a position separated from the mass analysis lens 22. The mass analysis slit 23 is configured such that the beam deflection direction (x direction) caused by the mass analysis magnet 21 becomes the slit width, and the opening 23a is relatively short in the x direction and relatively long in the y direction.

[0032] The mass spectrometry slit 23 may also be configured to have a variable slit width for adjusting mass resolution. The mass spectrometry slit 23 may also be configured to include two shields that can move in the slit width direction, with the slit width adjustable by changing the spacing between the two shields. The mass spectrometry slit 23 may also be configured to have a variable slit width by switching to one of multiple slits with different slit widths.

[0033] The beam stopping device 24 is configured to temporarily withdraw the ion beam from the beamline A, shielding the ion beam from being directed downstream toward the implantation chamber 16 (or wafer W). The beam stopping device 24 can be positioned at any location along the beamline A, for example, between the mass spectrometry lens 22 and the mass spectrometry slit 23. Because a certain distance is required between the mass spectrometry lens 22 and the mass spectrometry slit 23, positioning the beam stopping device 24 therebetween shortens the length of the beamline A compared to positioning the beam stopping device 24 at other locations, and the overall size of the ion implantation apparatus 10 can be reduced.

[0034] The beam stopping device 24 includes a pair of stopping electrodes 25 (25a, 25b) and a beam dump 26. The pair of stopping electrodes 25a, 25b are opposed across the beamline A, facing each other in a direction (y-direction) perpendicular to the beam deflection direction (x-direction) of the mass spectrometry magnet 21. The beam dump 26 is located downstream of the stopping electrodes 25a, 25b with respect to the beamline A, and is spaced apart from the beamline A in the direction in which the stopping electrodes 25a, 25b face each other.

[0035] The first parking electrode 25a is positioned above beamline A in the direction of gravity, and the second parking electrode 25b is positioned below beamline A in the direction of gravity. The beam dump 26 is provided further below beamline A in the direction of gravity and below the opening 23a of the mass spectrometry slit 23 in the direction of gravity. The beam dump 26 is formed, for example, from a portion of the mass spectrometry slit 23 where the opening 23a is not formed. The beam dump 26 may also be formed separately from the mass spectrometry slit 23.

[0036] The beam stopping device 24 deflects the ion beam by applying an electric field between a pair of stopping electrodes 25a and 25b, and causes the ion beam to retreat from the beam line A. For example, by applying a negative voltage to the second stopping electrode 25b based on the potential of the first stopping electrode 25a, the ion beam is deflected downward in the direction of gravity from the beam line A and is incident on the beam dump 26. Figure 2 In FIG, the dotted line indicates the trajectory of the ion beam toward the beam dump 26. Furthermore, the beam stopping device 24 sets the pair of stopping electrodes 25a and 25b to the same potential, thereby causing the ion beam to pass downstream along the beam line A. The beam stopping device 24 is configured to switch between a first mode in which the ion beam passes downstream and a second mode in which the ion beam is incident on the beam dump 26.

[0037] An injector Faraday cup 28 is provided downstream of the mass spectrometry slit 23. The injector Faraday cup 28 is configured to be able to enter and exit 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., y direction) perpendicular to the extending direction of the beamline A. Figure 2 As shown by the dotted line, when the implanter Faraday cup 28 is arranged on the beam line A, the ion beam toward the downstream side is blocked. Figure 2 As shown by the solid line, when the implanter Faraday cup 28 is removed from the beam line A, the blocking of the ion beam toward the downstream side is released.

[0038] The injector Faraday cup 28 is configured to measure the beam current of the ion beam being mass-analyzed by the mass spectrometer 20. The injector Faraday cup 28 measures the beam current while varying the magnetic field strength of the mass spectrometer magnet 21, thereby measuring the mass spectrometry spectrum of the ion beam. The mass resolution of the mass spectrometer 20 can be calculated using the measured mass spectrometry spectrum.

[0039] The beam shaper 30 includes a convergence / divergence device, such as a convergence / divergence quadrupole lens (Q lens), and is configured to shape the ion beam passing through the mass spectrometer 20 into a desired cross-sectional shape. For example, the beam shaper 30 is comprised of an electric field-type three-segment quadrupole lens (also known as a triple Q lens), comprising three quadrupole lenses 30a, 30b, and 30c. By using these three lens devices 30a-30c, the beam shaper 30 can independently adjust the convergence or divergence of the ion beam in the x- and y-directions. The beam shaper 30 may include a magnetic field-type lens device or a lens device that shapes the beam using both electric and magnetic fields.

[0040] The beam scanning unit 32 is configured to provide reciprocating scanning of the beam and is a beam deflecting device that scans the shaped ion beam in the x-direction. The beam scanning unit 32 has a pair of scanning electrodes that are opposed to each other in the beam scanning direction (x-direction). The scanning electrode pair is connected to a variable voltage power supply (not shown) and changes the electric field generated between the electrodes by periodically changing the voltage applied between the scanning electrode pair, thereby deflecting the ion beam to various angles. As a result, the entire scanning range of the ion beam in the x-direction is scanned. Figure 1 In FIG. 1 , the scanning direction and scanning range of the beam are exemplified by arrow X, and multiple trajectories of the ion beam in the scanning range are indicated by single-dot chain lines.

[0041] The beam collimator 34 is configured to parallelize the travel direction of the scanned ion beam with the designed trajectory of beamline A. The beam collimator 34 includes a plurality of arc-shaped collimating lens electrodes, each with a slit for the ion beam to pass through, located in the center in the y-direction. The collimating lens electrodes are connected to a high-voltage power supply (not shown). The applied voltage generates an electric field that acts on the ion beam, aligning the travel direction of the ion beam. Alternatively, the beam collimator 34 can be replaced by another beam collimating device, or a magnetic device utilizing a magnetic field.

[0042] An AD (Accel / Decel) column (not shown) for accelerating or decelerating the ion beam may be provided downstream of the beam parallelizing unit 34 .

[0043] The angular energy filter (AEF) 36 is configured to analyze the energy of the ion beam and deflect ions of the required energy downward and guide them to the implantation 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). Figure 2 In the embodiment of the present invention, a positive voltage is applied to the upper AEF electrode and a negative voltage is applied to the lower AEF electrode, thereby deflecting the ion beam downward. In addition, the angular energy filter 36 can be composed of a magnetic field deflection magnet device or a combination of an electric field deflection AEF electrode pair and a magnetic device.

[0044] 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 generating device 12 and the beamline device 14 are also referred to as a beam generating device. The beam generating device is configured to generate an ion beam for achieving desired implantation conditions by adjusting the operating parameters of various devices constituting the beam generating device.

[0045] The implantation chamber 16 includes an energy slit 38, a plasma shower device 40, side cups 42 (42L, 42R), a contour cup 44, and a beam stopper 46 in order from the upstream side of the beam line A. Figure 2As shown, the implantation chamber 16 includes a stage driving device 50 for holding one or more wafers W.

[0046] Energy slit 38 is located downstream of angular energy filter 36 and, together with angular energy filter 36, analyzes the energy of the ion beam incident on wafer W. Energy slit 38 is an energy defining slit (EDS) consisting of a slit extending transversely in the beam scanning direction (x-direction). Energy slit 38 allows ion beams with a desired energy value or energy range to pass toward wafer W while shielding ion beams with other energy values.

[0047] The plasma spray device 40 is located downstream of the energy slit 38. The plasma spray device 40 supplies low-energy electrons to the ion beam and the surface of the wafer W (wafer processing surface) according to the beam current of the ion beam, thereby suppressing the positive charge in the wafer processing surface caused by ion implantation. The plasma spray device 40 includes, for example, a spray pipe through which the ion beam passes and a plasma generator that supplies electrons into the spray pipe.

[0048] The side cups 42 (42R, 42L) are configured to measure the beam current of the ion beam during the ion implantation process on the wafer W. Figure 2 As shown, side cups 42R and 42L are positioned so as to be offset to the left and right (in the x-direction) relative to wafer W positioned on beamline A. They are positioned so as not to shield the ion beam directed toward wafer W during ion implantation. Since the ion beam is scanned in the x-direction beyond the area where wafer W is positioned, a portion of the scanned beam is incident on side cups 42R and 42L even during ion implantation. Thus, the beam current during ion implantation is measured via side cups 42R and 42L.

[0049] Contour cup 44 is configured to measure the beam current on the wafer processing surface. Contour cup 44 is movable by the operation of profile drive device 45, retracting from the implantation position where wafer W is located during ion implantation and retracting to the implantation position when wafer W is not located. By measuring the beam current while moving in the x-direction, contour cup 44 can measure the beam current across the entire beam scanning range in the x-direction. Contour cup 44 can also be formed into an array by arranging multiple Faraday cups in the x-direction, enabling simultaneous measurement of the beam current at multiple positions in the beam scanning direction (x-direction).

[0050] At least one of the side cup 42 and the outline cup 44 can include a single Faraday cup for measuring beam current, or an angle measuring instrument for measuring beam angle information. The angle measuring instrument, for example, includes a slit and multiple current detection units spaced apart from the slit in the beam travel direction (z-direction). The angle measuring instrument can measure the angular component of the beam in the slit width direction by, for example, measuring the beam passing through the slit using multiple current detection units arranged in the slit width direction. At least one of the side cup 42 and the outline cup 44 can also 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.

[0051] The stage drive device 50 includes a wafer holding device 52, a reciprocating motion mechanism 54, a torsion angle adjustment mechanism 56, and a tilt angle adjustment mechanism 58. The wafer holding device 52 includes an electrostatic chuck for holding the wafer W. The reciprocating motion mechanism 54 reciprocates the wafer held by the wafer holding device 52 in the y direction by causing the wafer holding device 52 to reciprocate in the reciprocating motion direction (y direction) perpendicular to the beam scanning direction (x direction). Figure 2 , the reciprocating motion of the wafer W is illustrated by arrow Y.

[0052] The torsion angle adjustment mechanism 56 adjusts the rotation angle of the wafer W. By rotating the wafer W about the normal to the wafer processing surface, it adjusts the torsion angle between an alignment mark provided on the wafer's outer periphery and a reference position. Here, a wafer alignment mark refers to a notch or orientation flat provided on the wafer's outer periphery, serving as a reference for the wafer's crystal axis direction or angular position along its circumference. The torsion angle adjustment mechanism 56 is disposed between the wafer holder 52 and the reciprocating mechanism 54, and reciprocates along with the wafer holder 52.

[0053] The tilt angle adjustment mechanism 58 adjusts the tilt of the wafer W by adjusting the tilt angle between the direction of travel 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 of rotation about the x-axis. The tilt angle adjustment mechanism 58 is disposed between the reciprocating mechanism 54 and the inner wall of the implantation chamber 16. The tilt angle of the wafer W is adjusted by rotating the entire stage drive device 50, including the reciprocating mechanism 54, in the R direction.

[0054] The stage driving device 50 holds the wafer W so as to be movable between an implantation position where the wafer W is irradiated with an ion beam and a transfer position where the wafer W is transferred in or out between the stage driving device 50 and the wafer transfer device 18 . Figure 2The wafer W is shown in the implantation position, with the stage drive unit 50 holding the wafer W so that the beam line A intersects the wafer W. The transport position of the wafer W corresponds to the position of the wafer holding unit 52 when the wafer W is transported in or out through the transport port 48 by a transport mechanism or transport robot provided in the wafer transport unit 18 .

[0055] Beam stopper 46 is provided at the most downstream side of beamline A, for example, mounted on the inner wall of implantation chamber 16. When wafer W is not on beamline A, the ion beam is incident on beam stopper 46. Beam stopper 46 is located near transfer port 48 connecting implantation chamber 16 and wafer transfer device 18, and is provided vertically below transfer port 48.

[0056] The beam blocker 46 is provided with a plurality of adjustment cups 47 (47a, 47b, 47c, and 47d). The adjustment cups 47 are Faraday cups configured to measure the beam current of the ion beam incident on the beam blocker 46. The adjustment cups 47 are arranged at intervals in the x-direction. For example, the adjustment cups 47 are used to simply measure the beam current at the implantation position without using the contour cup 44.

[0057] Side cups 42 (42L, 42R), outline cup 44, and adjustment cups 47 (47a to 47d) are multiple measuring devices for measuring beam current as a physical quantity of the ion beam. Side cups 42 (42L, 42R), outline cup 44, and adjustment cups 47 (47a to 47d) can also be multiple measuring devices for measuring beam angle as a physical quantity of the ion beam.

[0058] 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 implemented in hardware by components or mechanical devices, such as a computer CPU or memory, and in software by computer programs, etc. The various functions provided by the control device 60 can be implemented through the cooperation of hardware and software.

[0059] Figure 3 The top view schematically illustrates the configuration within the implantation chamber 16, showing a situation where a plurality of measuring devices disposed within the implantation chamber 16 measure the scanned beam SB. The ion beam B scans back and forth in the x-direction as indicated by arrow X, and is incident on the wafer W as the scanned beam SB that scans back and forth in the x-direction.

[0060] The ion beam B reciprocates within an irradiation range C3, which includes an implantation range C1 where the wafer W is located and monitoring ranges C2L and C2R located outside implantation range C1. Left and right side cups 42L and 42R are respectively disposed in monitoring ranges C2L and C2R. Side cups 42L and 42R can measure ion beam B that crosses into monitoring ranges C2L and C2R during the implantation process.

[0061] During the injection process, the contour cup 44 retreats to a non-irradiation range C4R, which is further outward from the irradiation range C3. In the illustrated configuration, the contour drive device 45 is positioned on the right side, and during the injection process, the contour cup 44 retreats to the non-irradiation range C4R on the right side. Alternatively, in a configuration where the contour drive device 45 is positioned on the left side, the contour cup 44 may retreat to the non-irradiation range C4L on the left side during the injection process.

[0062] Contour cup 44 is placed in implantation range C1 during a preparatory step performed prior to the implantation process, and measures the beam current of ion beam B within implantation range C1. Contour cup 44 measures the beam current while moving in the x-direction within implantation range C1, and also measures the beam current density distribution of scanning beam SB in the x-direction. Contour cup 44 moves in the x-direction along a plane (measurement plane MS) that coincides with the wafer processing surface during the implantation process, thereby measuring the beam current at a position on the wafer processing surface.

[0063] A plurality of adjustment cups 47 are disposed in the implantation range C1 to measure the beam current of the ion beam B in the implantation range C1. The plurality of adjustment cups 47 are disposed further downstream than the wafer W. Unlike the contour cup 44, the adjustment cup 47 does not need to move between the implantation range C1 and the non-irradiation range C4R. Therefore, compared with the contour cup 44, the beam current in the implantation range C1 can be measured more simply.

[0064] During the preparation process, beam current measurement values ​​are measured using various Faraday cups installed within the implantation chamber 16. Specifically, multiple beam current measurement values ​​are measured using side cups 42L and 42R, contour cup 44, and multiple adjustment cups 47. The control unit 60 stores the ratios between the acquired beam current measurement values, enabling calculation of the beam current value at the wafer processing surface based on the beam current measurement values ​​measured by side cups 42L and 42R during the implantation process. Generally, the ratio between the beam current measurement values ​​measured by the various Faraday cups depends on the settings of the beam optical system of the beamline assembly 14. Even if the beam current of the ion beam B extracted from the ion generation assembly 12 fluctuates slightly, the ratio between the beam current measurement values ​​remains approximately constant. In other words, if the beam optical system settings are determined during the preparation process, the ratio between the beam current measurement values ​​during the subsequent implantation process remains unchanged. Therefore, if the ratio between the beam current measurement values ​​is stored in the preparation process, the beam current value at the injection position (i.e., the wafer processing surface) of the ion implantation into the wafer W can be calculated in the implantation process based on the ratio and the beam current measurement value measured by the side cups 42L and 42R.

[0065] During the implantation process, the beam current can be constantly measured using the side cups 42L and 42R. During the implantation process, the beam current cannot be constantly measured using the contour cup 44 or the adjustment cup 47, and can only be measured intermittently. Therefore, during 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. In the event that 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 reciprocating speed of the wafer W in the y direction. For example, in the event that a uniform dose distribution is desired within the surface of 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, the reciprocating motion of the wafer W is accelerated when the monitored beam current measurement value increases, and the reciprocating motion of the wafer W is slowed down when the monitored beam current value decreases. This can prevent the deviation of the dose distribution within the wafer processing surface caused by the fluctuation of the beam current of the scanning beam SB.

[0066] Figure 4 2 is a block diagram schematically showing the functional configuration of the control device 60. The control device 60 includes an injection control unit 61, a measurement management unit 65, a model construction unit 69, and a storage unit 70.

[0067] The implantation control unit 61 controls the operation of the ion implantation apparatus 10 based on the implantation recipe. The measurement management unit 65 evaluates the validity of the measurements based on multiple measurement values ​​obtained by multiple measurement devices and corrects the measurement values ​​as needed. The measurement management unit 65 uses a model representing the correlation between the multiple measurement values ​​to evaluate the validity of the measurements and correct the measurement values. The model construction unit 69 constructs the model used by the measurement management unit 65. The storage unit 70 stores the implantation recipe or the operating parameters used to implement the implantation recipe, the measurement values ​​obtained by the multiple measurement devices, and the model representing the correlation between the multiple measurement values.

[0068] The injection control unit 61 includes an injection recipe acquisition unit 62 , a beam adjustment unit 63 , and a dose control unit 64 .

[0069] The implant recipe acquisition unit 62 acquires an implant recipe that defines implant parameters such as ion species, beam energy, beam current, beam size, wafer tilt angle, wafer twist angle, and average dose. The implant recipe may also define implant parameters for performing non-uniform implantation. The implant recipe may also define a two-dimensional dose distribution for non-uniform implantation, or a calibration file for variably controlling the beam scanning speed or wafer movement speed.

[0070] The beam adjustment unit 63 generates an ion beam based on the acquired implantation recipe. The beam adjustment unit 63 achieves the implantation parameters specified in the desired implantation recipe by adjusting the operating parameters of the various devices that constitute the ion implantation apparatus 10. The beam adjustment unit 63 controls the ion species of the ion beam by adjusting the gas species or extraction voltage of the ion generation apparatus 12, the magnetic field strength of the mass spectrometer 20, and the like. The beam adjustment unit 63 controls the beam energy of the ion beam by adjusting the extraction voltage of the ion generation apparatus 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 adjustment unit 63 controls the beam current of the ion beam by adjusting various parameters such as the gas volume, arc current, arc voltage, and source magnet current of the ion generation apparatus 12, or the opening width of the mass spectrometer slit 23. The beam adjustment unit 63 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.

[0071] The beam adjuster 63 adjusts the beam based on the measured values ​​of the physical quantities of the ion beam acquired in the preparation process. The beam adjuster 63 may also adjust the beam based on the measured values ​​calibrated by the measurement management unit 65 .

[0072] The dose control unit 64 controls the dose or dose distribution injected into the wafer W during the implantation process. When performing a non-uniform implantation, the dose control unit 64 variably controls the beam scanning speed and wafer movement speed based on the acquired implantation recipe. The dose control unit 64 variably controls the beam scanning speed by controlling the scanning voltage parameters commanded to the beam scanning unit 32, and variably controls the wafer movement speed by controlling the speed parameters commanded to the reciprocating mechanism 54.

[0073] The dose control unit 64 reduces the time-varying rate dV / dt of the scan voltage to slow down the beam scanning speed at relatively high-dose locations, and increases the time-varying rate dV / dt of the scan voltage to speed up the beam scanning speed at relatively low-dose locations. The dose control unit 64 slows down the wafer movement speed at relatively high-dose locations and speeds up the wafer movement speed at relatively low-dose locations.

[0074] The dose control unit 64 adjusts the beam scanning speed based on the measured values ​​of the physical quantities of the ion beam obtained in the preparation process. For example, the dose control unit 64 adjusts the beam scanning speed based on the measured values ​​of the beam current density distribution in the x-direction measured by the profile cup 44. The dose control unit 64 adjusts the wafer movement speed based on the measured values ​​of the physical quantities of the ion beam obtained in the implantation process. For example, the dose control unit 64 adjusts the wafer movement speed based on the measured beam current values ​​measured by the side cups 42L and 42R to reduce the impact of fluctuations in the beam current during the implantation process. The dose control unit 64 may also adjust at least one of the beam scanning speed and the wafer movement speed based on the measured values ​​calibrated by the measurement management unit 65.

[0075] The measurement management unit 65 includes a data set acquisition unit 66, a measurement evaluation unit 67, and a measurement correction unit 68. The data set acquisition unit 66 acquires a data set containing various data required for measurement evaluation and correction. The data set includes multiple measurement values ​​measured by multiple measurement devices. The data set includes, for example, multiple beam current measurement values ​​measured by the side cups 42L and 42R, the contour cup 44, and the adjustment cup 47. The data set may also include various parameters related to the beam being measured. The data set may also include at least one of the injection parameters determined in the injection recipe. The data set may also include at least one of the operation parameters of various devices used to achieve at least one injection parameter. The data set acquisition unit 66 may also store multiple data sets acquired in multiple injection processes in the storage unit 70. The multiple data sets stored in the storage unit 70 can be used as input data for model construction.

[0076] The measurement evaluation unit 67 evaluates whether the multiple measurement values ​​contained in the data set are appropriate based on the acquired data set. The measurement evaluation unit 67 refers to a model that represents the correlation between the multiple measurement values ​​when a normal measurement is performed, and when the correlation between the multiple measurement values ​​contained in the data set corresponds to the model, it determines that the multiple measurement values ​​are appropriate. In other words, it is determined that the measurement related to the multiple measurement values ​​is normal. On the other hand, when the correlation between the multiple measurement values ​​contained in the data set does not correspond to the model, it is determined that the multiple measurement values ​​are inappropriate. In other words, it is determined that there is an abnormality in the measurement related to the multiple measurement values. As an indicator representing the appropriateness of the measurement, for example, a value (such as a distance or deviation) that represents the extent to which the multiple measurement values ​​contained in the data set deviate from the model serving as a benchmark can be used. The details of the model representing the correlation between the multiple measurement values ​​will be described separately later.

[0077] The measurement corrector 68 corrects at least one of the multiple measurement values ​​included in the data set using a model representing the correlation between the multiple measurement values ​​when a normal measurement is performed. If the correlation between the multiple measurement values ​​deviates from the model, the measurement corrector 68 corrects at least one of the multiple measurement values ​​so that the corrected correlation between the multiple measurement values ​​corresponds to the model. For example, if a measurement related to the multiple measurement values ​​is determined to be abnormal, the measurement corrector 68 corrects at least one of the multiple measurement values ​​to a value estimated to be normal. The measurement corrector 68 can also correct at least one of the multiple measurement values ​​even if the measurement related to the multiple measurement values ​​is determined to be normal. By correcting the measurement values ​​based on the model, even if the measurement values ​​deviate from the model due to measurement error, etc., normal measurement values ​​can be corrected to more accurate values. The corrected measurement values ​​can be used for beam adjustment or dose control.

[0078] The model construction unit 69 constructs a model for use by the measurement evaluation unit 67 or the measurement correction unit 68. The model construction unit 69 receives as input a dataset containing multiple measurement values ​​obtained during normal measurements and constructs a model representing the correlation between the multiple measurement values. The model construction unit 69 obtains multiple datasets obtained during normal measurements and analyzes the correlation between the multiple measurement values ​​contained in each of the datasets to construct the model. The number of datasets required for model construction is not particularly limited and is, for example, 50 to 200.

[0079] The multiple data sets used in model construction may include measurement values ​​of ion beams generated at different times to achieve the same implantation process, or may include measurement values ​​of ion beams generated to achieve at least one different implantation recipe among the implantation parameters or operation parameters. Each of the multiple data sets may also include only measurement values ​​of ion beams for which at least one of the implantation parameters or operation parameters satisfies a specific condition. The model construction unit 69 may also construct the model using only data sets for which the characteristics of the wafer irradiated with the ion beam to be measured meet the specified conditions. For example, the model may be constructed using only data sets for when the device manufactured on the ion implanted wafer is operating normally.

[0080] Next, the construction of the model involved in this embodiment will be described in detail. Hereinafter, a model representing the correlation between seven beam current measurement values ​​measured by seven measuring devices, including the left and right side cups 42L, 42R, the contour cup 44, and the four adjustment cups 47a to 47d, will be used as an example for explanation. Furthermore, the physical quantity that becomes the object of model construction can be the beam current measurement value or the measurement value related to the beam angle measured by the above-mentioned cups. Furthermore, the number of measuring devices used to construct the model is not limited to seven and can be less than six or eight or more. However, the number of measuring devices is preferably three or more or four or more. By increasing the number of measuring devices, the accuracy of evaluating the validity of the measurement or the accuracy of correcting the measurement value can be improved.

[0081] The model construction unit 69 obtains a data set including a plurality of beam current measurement values ​​measured using a plurality of cups. The plurality of beam current measurement values ​​can be represented as array data having a dimension (e.g., 7 dimensions) equal to the number of cups n (e.g., 7) or a measurement value vector x (x1, x2, ..., x i ,……,x n ). The model building unit 69 obtains a plurality of measurement value vectors x and determines a function f(x) that represents the correlation between the plurality of measurement value vectors x obtained. The model building unit 69 determines a straight line that represents the correlation between the plurality of measurement value vectors x by, for example, principal component analysis (PCA). The straight line determined by the principal component analysis can be represented as a straight line extending in the principal component direction when the plurality of measurement value vectors x are plotted on an n-dimensional (7-dimensional) space. In addition, the function f(x) that represents the correlation between the plurality of measurement value vectors x is not limited to a straight line, and can also be any nonlinear function.

[0082] Figure 5 This is a diagram schematically showing a function showing the correlation between a plurality of measurement value vectors. Figure 5In the graph, due to the limitation of the description, only two dimensions of the measured value x1 of the first cup and the measured value x2 of the second cup are shown, but in fact it is n-dimensional (for example, 7-dimensional). The plots 72 on the graph are arranged at the position coordinates shown by the measured value vector x. The straight line 74 on the graph is an approximate straight line of the multiple plots 72 and is a function f(x) that represents the correlation between the multiple measured value vectors x. The straight line 74 is defined as a straight line that passes through the center of the distribution of the multiple plots 72 and extends in the direction of the first principal component. For example, if the center coordinates of the distribution of the multiple plots 72 are set to x0 and the unit vector in the direction of the first principal component is set to v, the intermediate variable t can be used to express the straight line 74 by the formula x0+tv.

[0083] The model building unit 69 determines a threshold value for evaluating the validity of the measurement based on the distribution of the plurality of measurement value vectors x. The threshold value for evaluating the validity of the measurement is defined as, for example, Figure 5 The reference region 76 shown in the diagram of FIG. If the measurement value vector x to be evaluated is located inside the reference region 76, the measurement value vector x is determined to be normal. On the other hand, if the measurement value vector x to be evaluated is located outside the reference region 76, the measurement value vector x is determined to be abnormal. The reference region 76 can be defined by a first range 76a along the first principal component direction of the straight line 74 and a second range 76b along the second principal component direction orthogonal to the straight line 74. The first range 76a can be defined based on T representing the deviation of the distribution in the first principal component direction. 2 T 2 The statistic can be calculated using the component t in the first principal component direction of the measurement value vector x and the standard deviation σ in the first principal component direction of the distribution. t , denoted as T 2 =Σ(t / σ t ) 2 The second range 76b can be defined using a Q statistic that represents the deviation of the distribution in a direction orthogonal to the first principal component direction. The Q statistic can be expressed as Q = Σq using the distance q from the first principal component axis (e.g., straight line 74) to the measurement value vector x. 2 The distance q can be calculated using the position coordinate x when the measurement value vector x is projected onto the first principal component axis. t =x0+tv, expressed as q=xx t The specific range of the threshold can be defined as T 2 The range within which the statistic or Q-statistic falls within a predetermined value can be defined by, for example, defining a threshold value such that 99.5% of the distribution of the plurality of measurement value vectors x is contained within reference region 76. Furthermore, the threshold value for defining reference region 76 need not be a fixed value but may be a variable value depending on the required implantation accuracy.

[0084] The model construction unit 69 may determine a plurality of threshold values ​​for one model. Figure 6 This is a diagram schematically showing multiple thresholds set for the model. Figure 6 In the example, the first reference region 77 and the second reference region 78 are set as multiple thresholds for a single model. The first reference region 77 is the range where the measured value vector x, the subject of evaluation, is normal. The measured value vector x contained in the first reference region 77 may or may not be corrected. The second reference region 78 is the range where the measured value vector x, the subject of evaluation, is abnormal and can be corrected. A range that does not correspond to either the first reference region 77 or the second reference region 78 is the range where the measured value vector x, the subject of evaluation, is abnormal and cannot be corrected.

[0085] The model construction unit 69 can construct a general model applicable to various implantation processes, or it can construct an individual model applicable only to a specific implantation recipe. For example, an individual model can be constructed by using only measurement value vectors x that satisfy specific conditions as input. For example, an individual model can be constructed by using only measurement value vectors x measured under conditions where specific implantation parameters or specific action parameters satisfy specified conditions as input for model construction. The model construction unit 69 can construct a general model by inputting the values ​​of the implantation parameters or action parameters into the model. In this case, the individual model can be constructed by restricting the values ​​of the implantation parameters or action parameters incorporated into the general model to satisfy the specified conditions. Here, the specific implantation parameters and action parameters can also be parameters that are not directly related to the measurement values. For example, in the case of a model for beam current measurement values, implantation parameters other than beam current, such as ion species, beam energy, or beam angle, or action parameters used to control implantation parameters other than beam current, can also be included as objects. Such a model can be referred to as a model that represents the correlation between multiple measurement values ​​and at least one implantation parameter or action parameter.

[0086] The model construction unit 69 may perform preprocessing on the measurement value vector x used as input for model construction. For example, the beam current measurement value x measured by a specific measurement device i may be used. i The mean μ of the distribution i and standard deviation σ i , so that the beam current measurement value x i Normalization. Normalized beam current measurement value x i ' can be expressed as x i '=(x i -μ i ) / σ i By setting the beam current measurement value x for each measuring device iNormalization can equalize the variation in measurement between cups, and thus make the contribution of each measurement device to the model uniform.

[0087] The model building unit 69 may also make the contribution of each measuring device to the model different for each measuring device. For example, an adjustment coefficient α representing the contribution of each measuring device may be set for each measuring device. i , the beam current measurement value x i Multiply by the adjustment factor α i The adjusted beam current measurement value α i x i As input to build the model. Adjustment coefficient α i The normalized beam current value x i 'Multiplying can also be standardized and adjusted beam current measurement value α i x i 'Use as input to build the model. Adjust the coefficient α i The value of can also be determined based on the reliability of the measurement in each measuring device. For example, the adjustment coefficient α of the measuring device with high reliability and little measurement error can be relatively increased. i On the other hand, the adjustment coefficient α of the measuring device that is prone to measurement errors and has low reliability is relatively reduced. i .

[0088] The model construction unit 69 may adjust the adjustment coefficient α for each model. i For example, for a specific model suitable for a specific injection recipe, the adjustment coefficient α for a specific measuring device can be i Set the adjustment coefficient α to a value different from that of the general model or other individual models. For example, in an implantation recipe requiring a high beam current, the beam tends to expand on the downstream side of beamline A, making it difficult for the entire beam diameter to enter the adjustment cup 47 located at the farthest downstream of beamline A. This results in a smaller value than the ideal beam current measurement value by the adjustment cup 47, increasing the measurement error. Therefore, in an individual model suitable for an implantation recipe where the beam tends to expand, the adjustment coefficient α applied to the adjustment cup 47 may be set to i By setting a smaller value, the measurement error in the adjustment cup 47 is less likely to be reflected in the model. In addition, the measurement value of the side cup 42 can be changed according to the beam scanning conditions. Therefore, in a separate model for an injection recipe for uneven injection, the adjustment coefficient α applied to the side cup 42 can also be adjusted according to the velocity distribution or scanning range of the beam scanning. i Variable. Adjustment coefficient α for a specific measuring device i Alternatively, they may be individually set based on the injection parameters determined in the injection process or the operation parameters for realizing the injection process.

[0089] Next, evaluation and correction of measurement values ​​using the constructed model will be described in detail.

[0090] The measurement and evaluation unit 67 acquires a data set containing a plurality of measurement values ​​to be evaluated. The measurement and evaluation unit 67 selects a model for evaluation based on the injection parameters or motion parameters included in the acquired data set. If a specific model corresponding to the injection parameters or motion parameters in the acquired data set has been constructed, the measurement and evaluation unit 67 uses the specific model corresponding to the acquired data set for evaluation. If a specific model corresponding to the injection parameters or motion parameters in the acquired data set has not been constructed, the measurement and evaluation unit 67 may use the general model for evaluation.

[0091] The measurement evaluation unit 67 evaluates the validity of the plurality of measurement values ​​included in the acquired data set with reference to the selected model. For example, the measurement evaluation unit 67 plots the measurement value vectors corresponding to the plurality of measurement values ​​acquired on the Figure 5 In the graph of , it is determined whether the plotted measurement value vector is included in the range of the reference area 76. If the measurement value vector is included in the range of the reference area 76, the measurement evaluation unit 67 determines that the measurement related to the acquired data set is normal. On the other hand, if the measurement value vector is outside the range of the reference area 76, it is determined that the measurement related to the acquired data set is abnormal. In the selected model, the measurement value vector is normalized or adjusted based on the adjustment coefficient α. i In the case of weighting, the measurement evaluation unit 67 applies normalization or weighting adjustment to the acquired plurality of measurement values ​​and then evaluates the validity of the measurement.

[0092] The measurement evaluation unit 67 may also refer to the selected model and calculate an index representing the validity of the plurality of measurement values. The measurement evaluation unit 67 may also calculate a value (deviation amount) representing the extent to which the measurement value vector 82 corresponding to the plurality of measurement values ​​deviates from the model as an index of the validity of the measurement value. For example, the distance from the straight line 74 shown in the model to the measurement value vector 82, that is, the distance in the direction orthogonal to the direction of the first principal component, may be calculated as the first index. The first index may also be calculated based on the above-mentioned Q statistic. Furthermore, the distance from the center coordinate x0 of the model to the measurement value vector 82 along the direction of the first principal component may also be calculated as the second index. The above-mentioned T may also be used to calculate the distance between the center coordinate x0 of the model and the measurement value vector 82. 2 The first and second indices may be standardized or normalized values ​​based on, for example, the standard deviation σ of the distribution. The measurement evaluation unit 67 may also evaluate the validity of the plurality of measurement values ​​based on at least one of the calculated first and second indices. The measurement evaluation unit 67 may also evaluate whether the measurement is normal or abnormal by comparing the calculated indices with thresholds corresponding to the reference regions 76, 77, and 78.

[0093] The measurement correction unit 68 corrects the plurality of measurement values ​​evaluated by the measurement evaluation unit 67 based on the model. Figure 7 The diagram schematically shows a method of correcting a measurement value vector. The measurement correction unit 68, for example, plots the measurement value vector 82 corresponding to the plurality of acquired measurement values ​​on the Figure 7 In the graph of FIG, the vector closest to the measured value vector 82 on the straight line 74 shown in the model is calculated as the corrected measured value vector 84. The correction direction from the measured value vector 82 before correction to the measured value vector 84 after correction shown by the arrow 80 is a direction orthogonal to the straight line 74 shown in the model.

[0094] The measurement correction unit 68 corrects the plurality of correction values ​​using the model used in the evaluation by the measurement evaluation unit 67. The measurement correction unit 68 normalizes the measurement value vector in the model or adjusts the value based on the adjustment coefficient α. i In the case of weighting, the measurement value vector is corrected after normalization and weight adjustment. The measurement correction unit 68 can also calculate the corrected measurement value by performing an inverse operation for canceling the normalization and weight adjustment on the corrected measurement value vector 84. Specifically, if the corrected measurement value vector 84 is set to y (y1, y2, ..., y i ,……,y n ), then the corrected beam current measurement value y i ' can be expressed as y i '=(σ i ·y i / α i )+μ i Here, α i is the adjustment coefficient for a specific measuring device i, σ i is the standard deviation in a particular measurement device i, μ i is the average value in a specific measuring device i.

[0095] The beam adjustment unit 63 may output an alarm and stop beam adjustment if the measurement evaluation unit 67 determines that the measurement is abnormal. The beam adjustment unit 63 may adjust the operating parameters of the beam generating device and readjust the beam to normalize the measurement if the measurement evaluation unit 67 determines that the measurement is abnormal. The beam adjustment unit 63 may also stop beam adjustment and output an alarm if the measurement evaluation unit 67 determines that the measurement is abnormal even after the beam has been readjusted.

[0096] The beam adjustment unit 63 may also adjust the beam current based on the corrected beam current measurement value y calculated by the measurement correction unit 68. i The beam adjustment unit 63 may also perform beam adjustment so that the corrected beam current measurement value y iThe beam current specified by the implantation process is obtained. The beam adjustment unit 63 can adjust the beam current measurement value y after correction corresponding to the specific measurement device i. i 'For beam adjustment, it is also possible to use the corrected beam current measurement value y in the contour cup 44, for example i 'Beam adjustment is performed based on the reference.

[0097] The dose control unit 64 may also use the corrected beam current measurement value y calculated by the measurement correction unit 68 to determine the corrected beam current measurement value y. i The dose control unit 64 can control the dose of the beam current measured by the corrected beam current value y corresponding to the specific measuring device i. i 'For dose control, it is also possible to use the corrected beam current measurement value y in the contour cup 44, for example i The dose control unit 64 can also use the corrected beam current measurement value y in the side cups 42L, 42R and the contour cup 44 to adjust the ion beam scanning speed distribution. i The wafer moving speed is adjusted based on the ratio of ' to reduce the influence of the fluctuation of the beam current during ion implantation.

[0098] Figure 8 The present invention is a flowchart schematically showing the process of the ion implantation method involved in the embodiment. The control device 60 obtains a data set containing a plurality of measurement values ​​(S10), and uses a model to evaluate the validity of the measurement of the plurality of measurement values ​​(S12). If the measurement is normal ("Yes" of S14), the ion implantation process is performed according to the acquired measurement value (S16). If the measurement is abnormal ("No" of S14), and the measurement value can be corrected ("Yes" of S18), the measurement value is corrected using the model (S20), and the ion implantation process is performed according to the correction value (S22). If the measurement value cannot be corrected ("No" of S18), and the beam cannot be adjusted ("Yes" of S24), the implantation process is terminated (S26). If the measurement value cannot be corrected ("No" of S18), and the beam can be adjusted ("No" of S24), the beam is readjusted (S28), and the process returns to the beginning, and the process after S10 is performed.

[0099] According to this embodiment, by using a model to evaluate the validity of measurements related to multiple measurement values, it is possible to detect the presence of measurement anomalies with higher accuracy. According to this embodiment, by referring to a model that represents the correlation between multiple measurement values ​​when they are normal, it is possible to easily determine that at least one of the multiple measurement values ​​has been measured when it deviates from the normal state. In particular, by increasing the number of measurement devices that are applicable to the model, even if a slight measurement error occurs in any of the measurement devices, the measurement error can be detected with high accuracy. As a result, ion implantation processing can be performed based on measurement values ​​that have been evaluated as normal with high accuracy, thereby improving implantation accuracy.

[0100] According to this embodiment, a model representing the normal correlation between multiple measured values ​​can be used to correct the measured values, and the ion implantation process can be performed based on the corrected values. Thus, if an abnormality occurs during measurement due to a slight measurement error, the ion implantation apparatus can be prevented from being stopped, thereby preventing a decrease in productivity due to the apparatus being stopped. Furthermore, by correcting the deviation from the model believed to be caused by the measurement error, the deviation of the measured values ​​caused by the measurement error can be reduced, thereby enabling the ion implantation process to be performed based on a more accurate value of the physical quantity. Thus, compared to a case where the measured values ​​are not corrected, the implantation accuracy can be improved.

[0101] While the present invention has been described above with reference to the various embodiments described above, the present invention is not limited to these embodiments. Appropriate combinations or substitutions of the structures of the various embodiments also fall within the scope of the present invention. Furthermore, based on the knowledge of those skilled in the art, it is also possible to appropriately rearrange the combinations or processing sequences in the various embodiments or to add various design changes to the embodiments, and embodiments incorporating such modifications also fall within the scope of the present invention.

[0102] In the above-mentioned embodiment, the model construction unit 69 may also update the constructed model each time. For example, by continuing to use the ion implantation apparatus 10, data sets are acquired in a plurality of implantation processes based on a plurality of implantation recipes and stored in the storage unit 70. The model construction unit 69 can update the model by increasing the number of drawn measurement value vectors reflected in the model based on the data sets stored in the storage unit 70. For example, by constructing a model based on the stored data sets, the number of types of individual models that can only be applied to specific implantation recipes can be increased. In the case where the use period of the ion implantation apparatus 10 is short, since only data sets corresponding to limited implantation recipes are stored, only individual models corresponding to limited implantation recipes can be constructed. On the other hand, if data sets corresponding to a plurality of implantation recipes are stored through long-term use of the ion implantation apparatus 10, various individual models corresponding to the plurality of implantation recipes can be constructed. By constructing a plurality of individual models for each implantation recipe, the evaluation accuracy of the validity of the measurement in a specific implantation recipe and the correction accuracy of the measured value can be improved.

[0103] The measurement evaluation unit 67 may evaluate the measurement using the general model before the individual model is constructed by the model construction unit 69, and evaluate the measurement using the individual model after the individual model is constructed by the model construction unit 69. In other words, the model used for evaluation may be dynamically switched based on the progress of model construction by the model construction unit 69. The model used for calibration by the measurement calibration unit 68 may also be the same.

[0104] Model construction unit 69 may update the model based on the results of the ion implantation process performed based on the corrected measurement values. For example, model construction unit 69 may also obtain information related to the characteristics or yield of devices manufactured on the ion-implanted wafer based on the corrected measurement values, and evaluate the impact of the correction of the measurement values. Model construction unit 69 may also update or reconstruct the model to reduce the adverse effects of the correction of the measurement values ​​on the devices.

[0105] The model constructed by the model construction unit 69 can also be used in other ion implantation devices. For example, the first model constructed based on the data set obtained by the first ion implantation device can be used to evaluate the validity of the measurement and correct the measured value in the second ion implantation device. In this case, the second model that performs the conversion processing on the first model can be used in the second ion implantation device instead of directly using the first model in the second ion implantation device. The second model can be a model that applies a specified conversion coefficient β to the first model. The conversion coefficient β, like the above-mentioned adjustment coefficient α, can be a coefficient set for each measuring device. For example, it can also be set to be respectively related to a plurality of beam current measurement values ​​x. i Multiplication conversion factor β i Conversion coefficient β iThe specific value of can also be determined based on a plurality of measurement values ​​obtained by the second ion implantation apparatus.

[0106] The above conversion factor β can also be used i , constructing an individual model for use in the second ion implantation apparatus. For example, consider a case where a general model (also referred to as the first general model) and an individual model (also referred to as the first individual model) are constructed in the first ion implantation apparatus, and only the general model (also referred to as the second general model) is constructed in the second ion implantation apparatus. The conversion coefficient β is calculated between the first general model and the second general model. i In the case of i An individual model (second individual model) used in the second ion implantation apparatus is constructed.

[0107] In the above embodiment, a model is used to perform both the evaluation and correction of the validity of multiple measurement values. In another embodiment, a model may be used to perform only the evaluation of the validity of multiple measurement values. In another embodiment, a model may be used to perform only the correction of multiple measurement values ​​without evaluating the validity of the measurement.

Claims

1. An ion implantation device, characterized in that: have: A beam generating device for generating an ion beam according to an implantation recipe; a plurality of measuring devices for measuring the beam current of the ion beam; and a control device that acquires a data set including a plurality of measurement values ​​measured by the plurality of measurement devices, and evaluates the validity of the measurement of the beam current of the ion beam using a pre-built model representing a correlation between the plurality of measurement values ​​and at least one implantation parameter determined in the implantation recipe; The at least one implantation parameter is any one of ion species, beam energy, beam current, beam size, wafer tilt angle, wafer twist angle, and average dose.

2. The ion implantation apparatus according to claim 1, wherein The control device obtains at least one injection parameter determined in the injection recipe as a parameter included in the data set.

3. The ion implantation apparatus according to claim 1 or 2, characterized in that: The control device adjusts an operating parameter of the beam generating device based on an evaluation result of validity of the measurement of the beam current of the ion beam.

4. The ion implantation apparatus according to claim 1 or 2, characterized in that: The control device corrects the value of the beam current of the ion beam using the model.

5. The ion implantation apparatus according to claim 1 or 2, characterized in that: The plurality of measuring devices include: a first measuring device for measuring the beam current of the ion beam at an implantation position where the ion beam is incident on the wafer; and a second measuring device for measuring the beam current of the ion beam at a position different from the implantation position. The control device corrects the measurement value of the first measurement device using the model.

6. The ion implantation apparatus according to claim 4, wherein: The control device controls a dose in an implantation process of irradiating a wafer with the ion beam based on the correction value of the beam current of the ion beam.

7. The ion implantation apparatus according to claim 1 or 2, characterized in that: The control device stores a plurality of data sets obtained in a plurality of injection processes based on different injection recipes, and constructs the model using the stored plurality of data sets as input.

8. The ion implantation apparatus according to claim 7, wherein: The control device constructs the model using, as input, the plurality of data sets acquired in the plurality of injection steps based on the injection recipe that satisfies predetermined conditions.

9. The ion implantation apparatus according to claim 7, wherein: The control device acquires information related to evaluation results of semiconductor devices manufactured using an implantation process irradiated with the ion beam, and constructs the model using as input a data set acquired in an implantation process used in manufacturing semiconductor devices whose evaluation results satisfy predetermined conditions.

10. A model generation method, characterized in that: include: a step of acquiring, from a plurality of measuring devices that measure ion beams generated according to an implantation recipe, a data set including a plurality of measured values ​​of at least one physical quantity representing a beam current of the ion beam; and a step of constructing a model representing a correlation between the plurality of measured values ​​of at least one injection parameter determined in the injection recipe and the plurality of data sets obtained in the plurality of injection steps based on the injection recipe as input; The at least one implantation parameter is any one of ion species, beam energy, beam current, beam size, wafer tilt angle, wafer twist angle, and average dose.

Images