Ion implantation device and ion implantation method

Abstract

This ion implantation device is provided with: a beam generation device that operates according to a plurality of operation parameters to generate an ion beam; an implantation process chamber in which an object to be processed is irradiated with the ion beam; a measurement device that measures beam characteristics of the ion beam; a memory in which a model for estimating the beam characteristics from a set of setting values of the plurality of operation parameters and a prescribed program are stored; and a processor that executes the prescribed program. According to the prescribed program, the processor: updates the model using a plurality of measurement values of the beam characteristics measured when each of a plurality of sets of the setting values of the plurality of operation parameters is set, and a plurality of estimated values of the beam characteristics estimated using the model from each of the plurality of sets; and uses the updated model to determine a target set of the setting values of the plurality of operation parameters for generating an ion beam that satisfies desired beam characteristics.

Description

Ion implantation apparatus and ion implantation method

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

[0002] In semiconductor manufacturing, a standard process is to implant ions into semiconductor wafers (also known as the ion implantation process) to change the conductivity or crystalline structure of the semiconductor. The equipment used in the ion implantation process is called an ion implanter. Ion implanters are configured to measure beam characteristics, such as the beam current and beam angle, of the ion beam to be irradiated onto the wafer, and adjust operating parameters based on the measurements to achieve the desired beam characteristics.

[0003] Japanese Patent Application Laid-Open No. 2022-122112

[0004] In recent years, the required accuracy of beam characteristics has become more stringent, and it can take time to adjust the beam characteristics to achieve the desired characteristics. Furthermore, even if operational parameters with a proven track record are used, it may not be possible to achieve the beam characteristics obtained in the past. In such cases, time-consuming measurements and adjustments must be repeated. If the adjustment time increases, the productivity of the ion implanter decreases.

[0005] It is an exemplary object of an embodiment of the present invention to provide a technique for adjusting operating parameters quickly and accurately.

[0006] An ion implantation apparatus according to one aspect of the present invention includes a beam generating device configured to generate an ion beam by operating in accordance with a plurality of operational parameters, an implantation processing chamber in which the ion beam is irradiated onto a workpiece, a measurement device for measuring beam characteristics of the ion beam, a memory storing a model for estimating the beam characteristics from a set of setting values ​​of the plurality of operational parameters, and a processor for executing the predetermined program, wherein the processor updates the model in accordance with the predetermined program using a plurality of measured values ​​of the beam characteristics measured when each of a plurality of sets of setting values ​​of the plurality of operational parameters is set as the plurality of operational parameters, and a plurality of estimated values ​​of the beam characteristics estimated from each of the plurality of sets using the model, and uses the updated model to determine a target set of setting values ​​of the plurality of operational parameters for generating an ion beam that satisfies desired beam characteristics.

[0007] Another aspect of the present invention is an ion implantation method comprising: measuring a plurality of measurements of beam characteristics of an ion beam generated by a beam generating device configured to operate in accordance with a plurality of operating parameters to generate an ion beam when the plurality of operating parameters are set to respective sets of setting values ​​of the plurality of operating parameters, estimating a plurality of estimates of the beam characteristics corresponding to the plurality of sets using a model for estimating beam characteristics from the sets of setting values ​​of the plurality of operating parameters, updating the model using the plurality of measurements and the plurality of estimates of the beam characteristics, determining a target set of setting values ​​of the plurality of operating parameters for generating an ion beam satisfying desired beam characteristics using the updated model, and irradiating a workpiece with the ion beam generated by the beam generating device when the target set of operating parameters is set.

[0008] Any combination of the above components or mutual substitution of the components or expressions of the present invention between methods, devices, systems, etc. are also valid aspects of the present invention.

[0009] According to one aspect of the present invention, operating parameters can be adjusted quickly and accurately.

[0010] 2( a ) and 2 ( b ) are front views showing the schematic configuration of an electrostatic quadrupole lens device. FIG. 2( a ) and 2 ( b ) are front views showing the schematic configuration of an electrostatic quadrupole lens device. FIG. 2( a ) and 2 ( b ) are a diagram showing a schematic configuration of a central control device. FIG. 2( a ) and 2 ( b ) are a diagram showing a schematic configuration of a central control device. FIG. 2( b ...

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are given the same reference numerals, and duplicated explanations will be omitted as appropriate. Furthermore, the configurations described below are examples and do not limit the scope of the present invention in any way.

[0012] Before describing the embodiments in detail, an overview will be provided. The ion implantation apparatus according to the present embodiment includes a beam generating device configured to generate an ion beam by operating in accordance with a plurality of operating parameters, an implantation processing chamber in which the ion beam is irradiated onto a workpiece, a measurement device for measuring beam characteristics of the ion beam, a memory storing a model for estimating the beam characteristics from a set of setting values ​​of the plurality of operating parameters and a predetermined program, and a processor for executing the predetermined program. The processor operates in accordance with the predetermined program and estimates the beam characteristics using the model from the set of setting values ​​of the plurality of operating parameters. Estimating the beam characteristics using the model may omit measurement of the beam characteristics, thereby making it possible to obtain desired beam characteristics without time-consuming repeated measurements and adjustments.

[0013] However, due to individual differences in ion implantation devices and changes over time, the actual state of the ion implantation device may deviate from the state estimated by the model, resulting in a decrease in the accuracy of the model's estimation of beam characteristics. In such cases, it becomes difficult to estimate beam characteristics with high accuracy using a model generated based on past performance data, etc. Therefore, in this embodiment, when the model's estimation accuracy is low, the model is updated using the relationship between the measured and estimated values ​​of beam characteristics, so that the state estimated by the updated model matches or approaches the current state of the ion implantation device. By updating the model as needed due to individual differences in ion implantation devices and changes over time, the model's estimation accuracy can be maintained high, and desired beam characteristics can be obtained without time-consuming repeated measurements and adjustments.

[0014] 1 is a top view schematically illustrating an ion implantation apparatus 100 according to an embodiment. The ion implantation apparatus 100 includes a beam generation device 110. The beam generation device 110 may include an ion generation device 12, a beam acceleration device 14, a beam deflection device 16, and a beam transport device 18. The ion implantation apparatus 100 further includes a substrate transfer and handling device 20. The beam generation device 110 may also be used as a term to refer to at least one of the ion generation device 12, the beam acceleration device 14, the beam deflection device 16, and the beam transport device 18.

[0015] The ion generator 12 has an ion source 10 and a mass analyzer 11. In the ion generator 12, an ion beam is extracted from the ion source 10, and the extracted ion beam is mass analyzed by the mass analyzer 11. The mass analyzer 11 has a mass analysis magnet 11a and a mass analysis slit 11b. The mass analysis slit 11b is disposed downstream of the mass analysis magnet 11a. As a result of the mass analysis by the mass analyzer 11, only the ion species required for implantation are selected, and the ion beam of the selected ion species is guided to the subsequent beam accelerator 14.

[0016] The beam accelerator 14 includes a plurality of linear accelerators 22a, 22b, and 22c that accelerate the ion beam, and a beam measurement unit 23, and constitutes a linearly extending portion of the beamline BL. Each of the plurality of linear accelerators 22a to 22c includes one or more stages of radio frequency acceleration units, and accelerates the ion beam by applying a radio frequency (RF) electric field to the ion beam. The beam measurement unit 23 is provided at the most downstream position of the beam accelerator 14, and measures at least one beam characteristic of the high-energy ion beam accelerated by the plurality of linear accelerators 22a to 22c. The beam measurement unit 23 may be a measurement device that measures beam characteristics such as beam energy, beam current, beam profile, and beam angle.

[0017] In this embodiment, three linear accelerators 22a to 22c are provided. The first linear accelerator 22a is provided in the upper stage of the beam accelerator 14 and includes a multi-stage (e.g., 5 to 15 stages) RF accelerator. The first linear accelerator 22a performs bunching, which aligns the continuous beam (DC beam) output from the ion generator 12 with a specific acceleration phase, and accelerates the ion beam to an energy of, for example, about 1 MeV. The second linear accelerator 22b is provided in the middle stage of the beam accelerator 14 and includes a multi-stage (e.g., 5 to 15 stages) RF accelerator. The second linear accelerator 22b accelerates the ion beam output from the first linear accelerator 22a to an energy of, for example, about 2 to 3 MeV. The third linear accelerator 22c is provided in the lower stage of the beam accelerator 14 and includes a multi-stage (e.g., 5 to 15 stages) RF accelerator. The third linear accelerator 22c accelerates the ion beam output from the second linear accelerator 22b to a high energy of, for example, 4 MeV or more.

[0018] The high-energy ion beam output from the beam accelerator 14 has a certain range of energy distribution. Therefore, in order to reciprocate scan and collimate the high-energy ion beam downstream of the beam accelerator 14 and irradiate the wafer, it is necessary to perform highly accurate energy analysis, control of energy dispersion, trajectory correction, and adjustment of beam convergence / divergence in advance.

[0019] The beam deflector 16 performs energy analysis, energy dispersion control, and trajectory correction of the high-energy ion beam output from the beam accelerator 14. The beam deflector 16 constitutes a portion of the beam line BL that extends in an arc shape. The high-energy ion beam is deflected by the beam deflector 16 and directed toward the beam transport device 18.

[0020] The beam deflection device 16 includes an energy analyzing electromagnet 24, a transverse focusing quadrupole lens 26 that suppresses energy dispersion, an energy analyzing slit 27, a first Faraday cup 28, a bending electromagnet 30 that provides steering (trajectory correction), and a second Faraday cup 31. The energy analyzing electromagnet 24 is also called an energy filter electromagnet (EFM). The group of devices consisting of the energy analyzing electromagnet 24, the transverse focusing quadrupole lens 26, the energy analyzing slit 27, and the first Faraday cup 28 is also collectively called the "energy analyzer."

[0021] The energy analysis slit 27 may be configured so that the slit width is variable in order to adjust the resolution of the energy analysis. The energy analysis slit 27 may be configured, for example, to be composed of two shields that are movable in the slit width direction, and the slit width may be adjustable by changing the distance between the two shields. The energy analysis slit 27 may be configured so that the slit width is variable by selecting one of a plurality of slits with different slit widths.

[0022] The first Faraday cup 28 is disposed immediately after the energy analysis slit 27 and is used to measure the beam current for energy analysis. The second Faraday cup 31 is disposed immediately after the bending electromagnet 30 and is provided to measure the beam current of the ion beam whose trajectory has been corrected and which enters the beam transport device 18. Each of the first Faraday cup 28 and the second Faraday cup 31 is configured to be able to be moved into and out of the beamline BL by the operation of a Faraday cup driver (not shown). Each of the first Faraday cup 28 and the second Faraday cup 31 may be a measurement device for measuring beam properties such as the beam current, beam profile, and beam angle.

[0023] The beam transport device 18 constitutes another linearly extending portion of the beam line BL, and runs parallel to the beam accelerator 14 across a maintenance area MA at the center of the device. The length of the beam transport device 18 is designed to be approximately the same as the length of the beam accelerator 14. As a result, the beam line BL, which is composed of the beam accelerator 14, beam deflector 16, and beam transport device 18, forms a U-shaped layout overall.

[0024] The beam transport device 18 includes a beam shaper 32, a beam scanner 34, a beam dump 35, a beam collimator 36, a final energy filter 38, and left and right Faraday cups 39L and 39R.

[0025] The beam shaper 32 includes a converging / diverging lens such as a quadrupole lens device (Q lens), and is configured to shape the ion beam that has passed through the beam deflection device 16 into a desired cross-sectional shape. The beam shaper 32 is configured, for example, by an electric field type triple-stage quadrupole lens (also called a triplet Q lens), and has three lens devices 32a, 32b, and 32c. By using the three lens devices 32a to 32c, the beam shaper 32 can independently adjust the convergence or divergence of the ion beam in each of the horizontal direction (x direction) and the vertical direction (y direction). The beam shaper 32 may include a magnetic field type lens device, or may include a lens device that shapes the beam using both an electric field and a magnetic field.

[0026] 2( a) and 2(b) are front views showing the schematic configurations of the electrostatic quadrupole lens devices 52 a and 52 b. The electrostatic quadrupole lens device 52 a in Fig. 2(a) is a horizontal converging lens that converges the ion beam IB in the horizontal direction (x direction), and the electrostatic quadrupole lens device 52 b in Fig. 2(b) is a vertical converging lens that converges the ion beam IB in the vertical direction (y direction).

[0027] The electrostatic quadrupole lens device 52a in Figure 2(a) has a pair of upper and lower lens electrodes 54a facing each other in the vertical direction (y direction) and a pair of left and right lens electrodes 56a facing each other in the horizontal direction (x direction). A negative potential -Qa is applied to the upper and lower lens electrodes 54a, and a positive potential +Qa is applied to the left and right lens electrodes 56a. The electrostatic quadrupole lens device 52a generates an attractive force between the upper and lower lens electrodes 54a, which are at a negative potential, and a repulsive force between the upper and lower lens electrodes 54a, which are at a positive potential, and the left and right lens electrodes 56a, which are at a positive potential, for the ion beam IB, which is composed of positively charged ions. In this way, the electrostatic quadrupole lens device 52a shapes the ion beam B so that it converges in the x direction and diverges in the y direction.

[0028] 2(a), the electrostatic quadrupole lens device 52b has a pair of upper and lower lens electrodes 54b facing each other in the vertical direction (y direction) and a pair of left and right lens electrodes 56b facing each other in the horizontal direction (x direction). In FIG. 2(b), the polarity of the applied potential is reversed from that in FIG. 2(a), with a positive potential +Qb applied to the upper and lower lens electrodes 54b and a negative potential −Qb applied to the left and right lens electrodes 56b. As a result, the electrostatic quadrupole lens device 52b shapes the ion beam B so that it converges in the y direction and diverges in the x direction.

[0029] The electrostatic quadrupole lens device 52a in Fig. 2A can be used, for example, as the second lens device 32b of the beam shaper 32. The electrostatic quadrupole lens device 52b in Fig. 2B can be used, for example, as the first lens device 32a and the third lens device 32c of the beam shaper 32.

[0030] Returning to FIG. 1 , the beam scanner 34 is a beam deflection device configured to provide reciprocating beam scanning and scans the shaped ion beam in the x-direction. The beam scanner 34 has a pair of scanning electrodes facing each other in the beam scanning direction (x-direction). The scanning electrode pair is connected to a variable voltage power supply (not shown), and by periodically changing the voltage applied between the scanning electrode pair, the electric field generated between the electrodes is changed, thereby deflecting the ion beam at various angles. As a result, the ion beam is scanned over a scanning range indicated by arrow X. In FIG. 1 , multiple trajectories of the ion beam in the scanning range are indicated by thin solid lines. Note that the beam scanner 34 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.

[0031] The beam scanner 34 deflects the beam beyond the scanning range indicated by the arrow X, causing the ion beam to be incident on a beam dump 35 provided at a position away from the beam line BL. The beam scanner 34 temporarily evacuates the ion beam from the beam line BL towards the beam dump 35, thereby blocking the ion beam so that it does not reach the downstream substrate transport and processing device 20.

[0032] The beam collimator 36 is configured to make the traveling direction of the scanned ion beam parallel to the designed trajectory of the beam line BL. The beam collimator 36 has a plurality of arc-shaped collimating lens electrodes each having a slit at the center for the ion beam to pass through. 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 to be parallel. Note that the beam collimator 36 may be replaced with another beam collimating device, and the beam collimating device may be configured as a magnet device that uses a magnetic field.

[0033] The final energy filter 38 is configured to analyze the energy of the ion beam and deflect ions of a required energy downward (in the -y direction) to guide them to the substrate transport and processing device 20. The final energy filter 38 is sometimes called an angular energy filter (AEF), and has a pair of AEF electrodes for electric field deflection. The AEF electrode pair is connected to a high-voltage power supply (not shown). 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 final energy filter 38 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 for magnetic field deflection.

[0034] The left and right Faraday cups 39L, 39R are provided downstream of the final energy filter 38 and are disposed at positions onto which the beams at the left and right ends of the scanning range indicated by the arrow X can be incident. The left and right Faraday cups 39L, 39R are provided at positions that do not block the beams directed toward the wafer W, and measure the beam current during ion implantation into the wafer W.

[0035] A substrate transfer and processing device 20 is provided downstream of the beam transport device 18, i.e., at the most downstream side of the beam line BL. The substrate transfer and processing device 20 includes an implantation processing chamber 40, a beam monitor 41, a beam profiler 42, a profiler driving device 43, a substrate transfer device 44, and a load port 46. The implantation processing chamber 40 is provided with a platen driving device (not shown) that holds the wafer W during ion implantation and moves the wafer W in a direction (y direction) perpendicular to the beam scanning direction (x direction).

[0036] The beam monitor 41 is provided at the most downstream position of the beam line BL inside the implantation processing chamber 40. The beam monitor 41 is provided at a position where the ion beam can be incident when no wafer W is present on the beam line BL, and is configured to measure beam characteristics before or between ion implantation processes. The beam monitor 41 may be a measuring device that measures beam characteristics such as beam current, beam current density distribution, beam angle, and beam parallelism. The beam monitor 41 is located, for example, near a transfer port (not shown) connecting the implantation processing chamber 40 and the substrate transfer device 44, and is provided at a position vertically below the transfer port.

[0037] The beam profiler 42 is configured to measure the beam current at a position on the surface of the wafer W. The beam profiler 42 is configured to be movable in the x direction by the operation of the profiler drive device 43, 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 located at the implantation position. The beam profiler 42 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 beam profiler 42 may have multiple Faraday cups arrayed in the x direction so that the beam current at multiple positions in the beam scanning direction (x direction) can be measured simultaneously. The beam profiler 42 may be a measurement device that measures the beam current density distribution in the x direction.

[0038] The beam profiler 42 may include a single Faraday cup for measuring the beam current, or may include an angle measuring device for measuring angular information of the beam. The angle measuring device may include, for example, a slit and multiple current detectors spaced apart from the slit in the beam propagation direction (z direction). The angle measuring device may measure the angular component of the beam in the slit width direction, for example, by measuring the beam passing through the slit with multiple current detectors arranged in the slit width direction. The beam profiler 42 may include a first angle measuring device capable of measuring angular information in the x direction and a second angle measuring device capable of measuring angular information in the y direction. The beam profiler 42 may be a measuring device that measures the beam angle in the x direction and the beam angle in the y direction. The beam profiler 42 may measure the angular center of gravity, convergence / divergence angles, etc. as angular information of the beam.

[0039] The substrate transfer device 44 is configured to transfer wafers W between a load port 46 on which a wafer container 45 is placed and the implantation processing chamber 40. The load port 46 is configured to simultaneously accommodate multiple wafer containers 45 and has, for example, four mounting tables arranged in the x direction. A wafer container transfer port (not shown) is provided vertically above the load port 46, and is configured to allow the wafer container 45 to pass through in the vertical direction. The wafer container 45 is automatically loaded into and automatically unloaded from the load port 46 through the wafer container transfer port by, for example, a transfer robot installed on the ceiling or the like in a semiconductor manufacturing factory where the ion implantation apparatus 100 is installed.

[0040] The ion implantation apparatus 100 further includes a central control unit 50. The central control unit 50 controls the overall operation of the ion implantation apparatus 100. The central control unit 50 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, and various functions provided by the central control unit 50 can be realized by cooperation between hardware and software.

[0041] A control panel 49 having a display device and input device for setting operating parameters of the ion implantation apparatus 100 is provided near the central control apparatus 50. The locations of the control panel 49 and the central control apparatus 50 are not particularly limited, but for example, the control panel 49 and the central control apparatus 50 can be located adjacent to an entrance / exit 48 of a maintenance area MA between the ion generation apparatus 12 and the substrate transport and processing apparatus 20. By locating the ion source 10, load port 46, control panel 49, and central control apparatus 50, which are frequently used by workers managing the ion implantation apparatus 100, adjacent to each other, work efficiency can be improved.

[0042] 3 is a diagram schematically illustrating the configuration of the central control device 50. The central control device 50 includes a processor 50a such as a central processing unit (CPU), a memory 50b such as a random access memory (RAM) or a read only memory (ROM), and a recording device 50c such as a hard disk drive (HDD) or a solid state drive (SSD).

[0043] The central control device 50 controls the overall operation of the ion implantation apparatus 100 in accordance with a program stored in, for example, the memory 50b, by the processor 50a executing the program. The processor 50a may execute a program stored in any storage device other than the memory 50b, may execute a program acquired from any recording medium by a reading device, or may execute a program acquired via a network. The memory 50b in which the program is stored may be a volatile memory such as a dynamic random access memory (DRAM), or may be a nonvolatile 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. Nonvolatile memory, magnetic recording media such as magnetic tape and magnetic disks, and optical recording media such as optical disks are examples of non-transitory, tangible, computer-readable storage media.

[0044] The various functions provided by the central control device 50 may be realized by a single device including a processor 50 a and a memory 50 b, or may be realized by cooperation of multiple devices each including a processor 50 a and a memory 50 b. The recording device 50 c records data indicating the operational performance of the ion implantation device 100. The recording device 50 c may be provided in the central control device 50, or may be provided as an external device separate from the central control device 50.

[0045] Fig. 4 is a block diagram showing a schematic functional configuration of the central control unit 50. The central control unit 50 includes an automatic adjustment unit 60, a measurement control unit 62, an estimation unit 64, a model evaluation unit 66, and a model update unit 68. Each functional block shown in Fig. 4 is realized by the processor 50a executing a program stored in the memory 50b.

[0046] The automatic adjustment unit 60 executes an automatic adjustment program for adjusting multiple operational parameters, and adjusts the multiple operational parameters so as to achieve desired beam characteristics. The measurement control unit 62 controls the operation of the measurement device and acquires measured values ​​of at least one beam characteristic of the ion beam. The estimation unit 64 calculates an estimated value of the beam characteristics from the set value of at least one operational parameter using a model that indicates the correlation between at least one operational parameter and the beam characteristics. The model evaluation unit 66 evaluates the validity of the model used by the estimation unit 64 by comparing the measured and estimated values ​​of the beam characteristics. If the model evaluation unit 66 evaluates that the model is invalid, the model update unit 68 updates the model using the measured and estimated values ​​of the beam characteristics. Data of the model used to estimate the beam characteristics is stored, for example, in the memory 50b or the recording device 50c.

[0047] FIG. 5 is a flowchart showing an example of a method for adjusting operational parameters. First, a set of setting values ​​for multiple operational parameters (also referred to as an initial set) is set (S10). Next, multiple beam characteristics of the ion beam are adjusted (S12 to S20). In the example of FIG. 5, the beam energy (S12), beam current (S14), beam angle (S16), beam parallelism (S18), and beam current density distribution (S20) are adjusted in this order. Finally, the set of setting values ​​for multiple operational parameters (also referred to as a target set) obtained when the adjustments are completed is saved (S22). Note that the order of adjustments in S12 to S20 does not matter, and the order of adjustments may be reversed as appropriate. Furthermore, adjustment of a specific beam characteristic may be performed multiple times. For example, a first beam characteristic may be adjusted, a second beam characteristic may be adjusted, and then the first beam characteristic may be adjusted again.

[0048] In S10, for example, an initial set is determined according to the target beam characteristics. The automatic adjustment unit 60 may determine the initial set by simulation using a predetermined algorithm. The automatic adjustment unit 60 may determine the initial set based on a past set of setting values ​​stored in the recording device 50c. For example, if there is a past set of setting values ​​that has produced an ion beam having beam characteristics that match or are close to the target beam characteristics, the setting values ​​of the operational parameters included in that set may be used as at least a part of the initial set.

[0049] In the beam energy adjustment in S12, the operating parameters of the ion generator 12 and the beam accelerator 14 are adjusted. Specifically, the extraction voltage of the ion source 10, the RF voltage V applied to each of the multiple RF accelerator stages included in the beam accelerator 14, ＲＦ The beam energy is adjusted by adjusting operational parameters such as the amplitude, frequency, and phase of the beam. The beam energy is measured by the beam measurement unit 23, for example.

[0050] In the beam current adjustment in S14, the operating parameters of the ion generator 12 and the beam deflector 16 are adjusted. Specifically, the beam current is adjusted by adjusting operating parameters such as the source gas flow rate, arc current, arc voltage, and source magnet current of the ion source 10, and the slit opening widths of the mass analysis slit 11b and the energy analysis slit 27. The beam current is measured by, for example, the beam measurement unit 23, the first Faraday cup 28, the second Faraday cup 31, the beam monitor 41, or the beam profiler 42.

[0051] In the beam angle adjustment in S16, the operating parameters of the beam deflection device 16 and the beam transport device 18 are adjusted. For example, the beam angle center of gravity in the x direction is adjusted by the magnet current of the bending electromagnet 30. The beam angle center of gravity in the y direction is adjusted by the applied voltage to the final energy filter 38. The convergence / divergence angles in the x and y directions are adjusted by the applied voltages to the lens devices 32a to 32c included in the beam shaper 32. The beam sizes in the x and y directions may be adjusted by adjusting the applied voltages to the lens devices 32a to 32c. The beam angles and beam sizes in the x and y directions are measured by, for example, the beam monitor 41 or the beam profiler 42.

[0052] In the adjustment of the beam parallelism in S18, the operating parameters of the beam transport device 18 are adjusted. Specifically, the beam parallelism is adjusted by adjusting the voltage applied to the collimating lens electrodes included in the beam collimator 36. The beam parallelism is measured by, for example, the beam monitor 41 or the beam profiler 42.

[0053] In the adjustment of the beam current density distribution in S20, the operating parameters of the beam transport device 18 are adjusted. Specifically, the beam current density distribution in the x direction is adjusted by adjusting the voltage waveform applied to the scanning electrode pair included in the beam scanner 34. The beam current density distribution is measured by, for example, the beam monitor 41 or the beam profiler 42.

[0054] In the adjustment steps S12 to S20, for example, the beam characteristics to be adjusted are measured, and at least one operating parameter is adjusted based on the measured values ​​of the beam characteristics. The measurement control unit 62 operates the measurement device to obtain the measured values ​​of the beam characteristics to be adjusted. If the measured values ​​of the beam characteristics satisfy the desired conditions, the automatic adjustment unit 60 ends the adjustment of the beam characteristics to be adjusted. If the measured values ​​of the beam characteristics do not satisfy the desired conditions, the automatic adjustment unit 60 adjusts the set values ​​of the operating parameters so that the beam characteristics satisfy the desired conditions.

[0055] In the adjustment steps S12 to S20, instead of measuring the beam characteristics to be adjusted, estimated values ​​of the beam characteristics may be calculated, and at least one operating parameter may be adjusted based on the estimated values ​​of the beam characteristics. The estimation unit 64 calculates the estimated values ​​of at least one beam characteristic using a model. If the estimated values ​​of the beam characteristics satisfy desired conditions, the automatic adjustment unit 60 may skip measuring the beam characteristics to be adjusted and terminate adjustment of the beam characteristics to be adjusted. If the estimated values ​​of the beam characteristics do not satisfy the desired conditions, the automatic adjustment unit 60 may adjust at least one operating parameter using a model. For example, the automatic adjustment unit 60 may use the model to calculate values ​​of operating parameters that will cause the estimated values ​​of the beam characteristics to satisfy the desired conditions. If the estimated values ​​of the beam characteristics obtained from the estimation unit 64 do not satisfy the desired conditions, the automatic adjustment unit 60 may adjust the set values ​​of the operating parameters based on the estimated values. If adjustment of the operating parameters based on estimated values ​​is unsuccessful, the automatic adjustment unit 60 may adjust the operating parameters based on measured values.

[0056] FIG. 6 is a flowchart showing an example of a beam characteristic adjustment method. FIG. 6 shows details of the steps for adjusting one beam characteristic in each of S12 to S20 in FIG. 5 . If a predetermined condition is met (Y in S30), the beam characteristic to be adjusted is estimated using a model (S32). If the predetermined condition is not met (N in S30), the beam characteristic to be adjusted is measured using a measurement device (S34). Here, the predetermined condition in S30 can include various conditions. Examples of cases where the predetermined condition is met include when a model for estimating the beam characteristic to be adjusted exists, when the model used for estimation is valid, and when the number of adjustments based on estimated values ​​is less than a predetermined number. If adjustment of the estimated or measured beam characteristic is necessary (Y in S36), the operating parameters are adjusted based on the estimated or measured value of the beam characteristic (S38), and the process returns to S30. If adjustment of the beam characteristic is not necessary in S36 (N in S36), this flow ends.

[0057] As an example of the flow of FIG. 6 , if a predetermined condition is satisfied in S30, the operating parameters are adjusted based on the estimated value of the beam characteristics, and the adjustment of the operating parameters is completed when the estimated value of the beam characteristics meets the desired condition. In this case, measurement of the beam characteristics is skipped in the beam characteristics adjustment process, thereby reducing the time required for measuring the beam characteristics. On the other hand, if a predetermined condition is not satisfied in S30, the operating parameters are adjusted based on the measured value of the beam characteristics, and the adjustment of the operating parameters is completed when the measured value of the beam characteristics meets the desired condition. For example, by measuring the beam characteristics when the estimated value of the beam characteristics is inappropriate or when adjustments based on the estimated value of the beam characteristics have been repeated a predetermined number of times, the operating parameters can be more reliably adjusted based on the measured value.

[0058] The model evaluation unit 66 evaluates the validity of the model. The model evaluation unit 66 evaluates the validity of the model by comparing the measured values ​​and estimated values ​​of the beam characteristics. The model evaluation unit 66 compares the measured values ​​measured when specific operating parameters are set with the estimated values ​​when the specific operating parameters are input to the model. For example, if the difference between the measured values ​​and the estimated values ​​is less than a predetermined threshold, the model evaluation unit 66 evaluates the model as valid, and if the difference between the measured values ​​and the estimated values ​​is equal to or greater than the predetermined threshold, the model evaluation unit 66 evaluates the model as invalid. The magnitude of the threshold can be set appropriately for each beam characteristic, for example, depending on the accuracy required for the beam characteristics.

[0059] The model evaluation unit 66 may evaluate the validity of the model using multiple measured values ​​and multiple estimated values. The model evaluation unit 66 may compare multiple measured values ​​and multiple estimated values ​​and evaluate the validity of the model based on the agreement between the two. When the beam characteristics have extreme values ​​(maximum or minimum) in response to a change in the setting value of at least one operating parameter, the model evaluation unit 66 may evaluate the validity of the model by comparing the extreme values ​​calculated from the multiple measured values ​​with the extreme values ​​calculated from the multiple estimated values. In this case, the model evaluation unit 66 determines a range in the model in which the extreme values ​​of the beam characteristics exist, the automatic adjustment unit 60 changes the setting value of at least one operating parameter within the determined range, the measurement control unit 62 measures the beam characteristics to obtain measured values, and the estimation unit 64 calculates estimated values ​​of the beam characteristics. This allows the model evaluation unit 66 to compare the extreme values ​​of the multiple measured values ​​with the extreme values ​​of the multiple estimated values.

[0060] If the model evaluation unit 66 evaluates the model as being invalid, the model updating unit 68 updates the model using the measured and estimated values ​​of the beam characteristics. The model updating unit 68 updates the model so that the estimated value of at least one operational parameter estimated from the updated model matches the measured beam characteristics or minimizes the difference between them. The model updating unit 68 may update the model by linearly transforming the set value of at least one operational parameter, for example, by adding or multiplying the set value of the at least one operational parameter by a constant. The model updating unit 68 may update the model by linearly transforming the estimated value of the beam characteristics, for example, by adding or multiplying the estimated value of the beam characteristics by a constant. If the measured value of the beam characteristics has an extreme value and the estimated value of the beam characteristics in the model also has an extreme value, the model updating unit 68 may update the model so that the extreme value of the measured value of the beam characteristics matches the extreme value of the estimated value. If the model evaluation unit 66 evaluates the model as being valid, the model updating unit 68 does not need to update the model.

[0061] When the model is updated, the automatic adjustment unit 60 can use the updated model to determine a target set of setting values ​​for at least one operational parameter for generating an ion beam that satisfies the desired beam characteristics. By using the appropriately updated model, the automatic adjustment unit 60 can generate an ion beam that satisfies the desired beam characteristics using the target set as is. In this case, the time required for beam adjustment can be significantly reduced, and the beam characteristics can be adjusted with high precision.

[0062] 7 is a diagram schematically illustrating an example of a model 70 showing the correlation between the setting values ​​of multiple operating parameters and one beam characteristic. This model 70 illustrates a case in which the multiple operating parameters are the voltages applied to the lens devices 32a-32c, and the one beam characteristic is the beam width in the x-direction. The first operating parameter shown on the horizontal axis is, for example, a first potential Qa applied to the first lens device 32a and the third lens device 32c, and the second operating parameter shown on the vertical axis is, for example, a second potential Qb applied to the second lens device 32b.

[0063] In the model 70 shown in FIG. 7 , the beam width in the x-direction, which is a beam characteristic, has a minimum value at the position of the thick line 72 and increases in value as it moves away from the thick line 72. A target region 74 adjacent to the thick line 72 is a region where the beam width in the x-direction is within the target value range. An allowable region 76 outside the target region 74 is a region where the beam width in the x-direction is greater than the target value but less than the tolerance value. An unacceptable region 78 outside the tolerance region 76 is a region where the beam width in the x-direction is greater than the tolerance value. When adjusting the beam width in the x-direction, the set values ​​Qa and Qb of multiple operating parameters are adjusted so that the value of the beam width in the x-direction is within the target value range or less than the tolerance value, that is, so that it is included in the target region 74 or the tolerance region 76.

[0064] When evaluating the validity of the model 70, the model evaluation unit 66 determines multiple sets of setting values ​​of multiple operating parameters to be used for the evaluation. Here, the set of setting values ​​of multiple operating parameters means a combination of setting values ​​Qa, Qb of multiple operating parameters, and corresponds to a coordinate point (Qa, Qb) defined by the combination of setting values ​​of the multiple operating parameters. In order to evaluate the model 70, the model evaluation unit 66 determines multiple coordinate points defined by each of the multiple sets.

[0065] FIG. 8 is a schematic diagram showing multiple sets of setting values ​​for multiple operating parameters set on a model 70. Multiple coordinate points 80a-80e or 82a-82e corresponding to the multiple sets are set along a line segment 80 or 82 drawn on the model 70. The line segment 80 or 82 is set so as to intersect with the thick line 72 indicating the extreme value of the beam characteristics. The first line segment 80 represents a case where the line segment is set perpendicular to the thick line 72 indicating the extreme value. The second line segment 82 represents a case where the line segment is set so as to intersect diagonally with the thick line 72 indicating the extreme value. The second line segment 82 can be set so that at least one of the multiple operating parameters has a fixed value. In the example of FIG. 8, the second line segment 82 is set so that the setting value Qb of the second operating parameter is constant.

[0066] Three or more coordinate points 80a-80e or 82a-82e corresponding to the multiple sets can be set on the line segment 80 or 82. By setting at least three coordinate points, the positions of the extrema of the beam characteristics can be calculated from the measured or estimated values ​​of the beam characteristics corresponding to the at least three coordinate points. For example, by fitting a polynomial (e.g., a quadratic function) having extrema to the measured or estimated values ​​of the beam characteristics corresponding to the multiple coordinate points, the extrema of the fitted polynomial can be regarded as the extrema of the beam characteristics. By setting the line segment 80 or 82 to intersect with the thick line 72 indicating the extrema, the multiple sets can be set so that the extrema of the measured and estimated values ​​of the first beam characteristic are located within a range that includes the multiple coordinate points 80a-80e or 82a-82e. The length of the line segment 80 or 82 corresponding to the range in which the multiple coordinate points are set is preferably long enough to be appropriate for calculating the extrema. For example, each end of the line segment 80 or 82 is preferably located within the allowed region 76 or the unallowable region 78.

[0067] The model evaluation unit 66 can evaluate the validity of the model using multiple measured values ​​of beam characteristics measured when each of the multiple sets is set and multiple estimated values ​​of beam characteristics estimated using the model from each of the multiple sets. The model evaluation unit 66 may compare the multiple measured values ​​with the multiple estimated values ​​and evaluate the validity of the model based on the agreement between the multiple measured values ​​and the multiple estimated values. The model evaluation unit 66 may compare extreme values ​​of measured values ​​calculated from the multiple measured values ​​with extreme values ​​of estimated values ​​calculated from the multiple estimated values ​​and evaluate the validity of the model based on the agreement between the extreme values. For example, the model evaluation unit 66 may compare a first set of setting values ​​corresponding to the extreme values ​​of the measured values ​​with a second set of setting values ​​corresponding to the extreme values ​​of the estimated values ​​and evaluate the validity of the model based on the agreement between the first set and the second set. The agreement between the first set and the second set can be evaluated, for example, using the distance between a first coordinate point corresponding to the first set and a second coordinate point corresponding to the second set.

[0068] FIG. 9 is a diagram schematically illustrating an example of a method for evaluating the validity of a model. FIG. 9 illustrates a case in which multiple coordinate points 80a to 80e corresponding to multiple sets are set on the first line segment 80 illustrated in FIG. 8. Plots 84a to 84e illustrated in FIG. 9 represent multiple measured values ​​of beam characteristics (i.e., beam width in the x-direction) measured when each of the multiple sets is set. Plots 86a to 86e illustrated in FIG. 9 represent multiple estimated values ​​of beam characteristics (i.e., beam width in the x-direction) estimated using a model from each of the multiple sets. Curve 84 is a quadratic function fitted to plots 84a to 84e of the multiple measured values. Using curve 84, an extreme value 84p of the measured values ​​can be calculated, and a coordinate point 80p indicating the first set of setting values ​​corresponding to extreme value 84p of the measured values ​​can be calculated. Curve 86 is a quadratic function fitted to plots 86a to 86e of the estimated values. The curve 86 can be used to calculate extreme values ​​86q of the estimated values, and a coordinate point 80q indicating a second set of setting values ​​corresponding to the extreme values ​​86q of the estimated values ​​can be calculated. The model evaluation unit 66 can evaluate the validity of the model using a difference 88 between the extreme values ​​84p of the measured values ​​and the extreme values ​​86q of the estimated values. The model evaluation unit 66 can evaluate the validity of the model using a distance 89 between the coordinate point 80p indicating the first set of setting values ​​and the coordinate point 80q indicating the second set of setting values.

[0069] The model update unit 68 can update the model so that the updated model matches a curve 84 fitted to plots 84a to 84e of multiple measured values. For example, the model can be updated by linearly transforming a curve 86 fitted to plots 86a to 86e of multiple estimated values, and the linearly transformed curve matches the curve 84. Specifically, the model can be updated by multiplying the curve 86 by a constant to scale the model, or by adding a constant to the curve 86 to translate the model.

[0070] FIG. 10 is a diagram schematically illustrating an example of a model showing the correlation between the setting values ​​of multiple operational parameters and one beam characteristic. FIG. 10 shows a model 90 in which the multiple operational parameters are the applied voltages Qa and Qb to the lens devices 32a to 32c, and one beam characteristic is the beam width in the y direction. The model 70 in FIG. 7 can be considered a first model for estimating the beam width in the x direction, which is a first beam characteristic, and the model 90 in FIG. 10 can be considered a second model for estimating the beam width in the y direction, which is a second beam characteristic. The first model 70 in FIG. 7 and the second model 90 in FIG. 10 estimate the first beam characteristic and the second beam characteristic using a common first operational parameter Qa and a common second operational parameter Qb as inputs.

[0071] In the second model 90 shown in FIG. 10 , the beam width in the y direction, which is the second beam characteristic, has a minimum value at the position of the thick line 92 and increases in value as it moves away from the thick line 92. A target region 94 adjacent to the thick line 92 is a region where the beam width in the y direction is within the target value range. An allowable region 96 outside the target region 94 is a region where the beam width in the y direction is greater than the target value but less than the allowable value. An unacceptable region 98 outside the allowable region 96 is a region where the beam width in the y direction is greater than the allowable value. When adjusting the beam width in the y direction, the set values ​​Qa and Qb of multiple operating parameters are adjusted so that the value of the beam width in the y direction is within the target value range or less than the allowable value, that is, so that it is included in the target region 94 or the allowable region 96.

[0072] FIG. 11 is a schematic diagram illustrating a method for determining a target set of setting values ​​for multiple operating parameters using multiple models. FIG. 11 shows the first model 70 shown in FIG. 7 and the second model 90 shown in FIG. 10 superimposed on each other. Typically, the first beam characteristic, i.e., the beam width in the x-direction, and the second beam characteristic, i.e., the beam width in the y-direction, are both required to be within a target value range or within a tolerance value at the same time. In this case, the target set may be determined within a target region 104 or an acceptable region 106 near an intersection 102 between the thick line 72 representing the extreme value of the first beam characteristic in the first model 70 and the thick line 92 representing the extreme value of the second beam characteristic in the second model 90. The target region 104 shown in FIG. 11 is the overlapping range between the target region 74 in FIG. 7 and the target region 94 in FIG. 10. The acceptable region 106 shown in FIG. 11 is the overlapping range between the acceptable region 76 in FIG. 7 and the acceptable region 96 in FIG. 10.

[0073] The model evaluation unit 66 can determine multiple common sets of setting values ​​of multiple operating parameters to be used in the evaluation in order to simultaneously evaluate the validity of each of the first model 70 and the second model 90. For example, as shown in FIG. 11 , multiple coordinate points 108a-108e corresponding to the multiple common sets can be set along a line segment 108. The line segment 108 is set so as to intersect with both the thick line 72 indicating the extreme value of the first beam characteristic and the thick line 82 indicating the extreme value of the second beam characteristic. The line segment 108 is set so as to intersect with the target region 104 and the allowable region 106. The length of the line segment 108, which corresponds to the range in which the multiple coordinate points are set, is preferably long enough to be appropriate for calculating the extreme values. For example, each of the ends of the line segment 108 is preferably located within the allowable region 106 or outside the allowable region 106. By setting multiple common sets, each of the first model 70 and the second model 90 can be simultaneously evaluated.

[0074] The model evaluation unit 66 can evaluate the validity of the first model 70 using a plurality of first measurement values ​​of the first beam characteristic when each of the common sets is set and a plurality of first estimate values ​​of the first beam characteristic estimated using the first model 70 from each of the common sets. The model evaluation unit 66 may evaluate the validity of the first model 70 using extreme values ​​of the first measurement values ​​calculated from the plurality of first measurement values ​​and extreme values ​​of the first estimate values ​​calculated from the plurality of first estimate values. The model evaluation unit 66 may evaluate the validity of the first model 70 by comparing a first set of setting values ​​corresponding to the extreme values ​​of the first measurement values ​​with a second set of setting values ​​corresponding to the extreme values ​​of the first estimate values. The model evaluation unit 66 can evaluate the validity of the second model 90 using a plurality of second measurement values ​​of the second beam characteristic when each of the common sets is set and a plurality of second estimate values ​​of the second beam characteristic estimated using the second model 90 from each of the common sets. The model evaluation unit 66 may use extreme values ​​of the second measurement values ​​calculated from the plurality of second measurement values ​​and extreme values ​​of the second estimated values ​​calculated from the plurality of second estimated values ​​to evaluate the validity of the second model 90. The model evaluation unit 66 may evaluate the validity of the second model 90 by comparing a third set of setting values ​​corresponding to the extreme values ​​of the second measurement values ​​with a fourth set of setting values ​​corresponding to the extreme values ​​of the second estimated values.

[0075] The model updating unit 68 may update at least one of the first model 70 and the second model 90 using the common multiple sets. The model updating unit 68 can update the first model 70 using multiple first measurement values ​​of the first beam characteristic when each of the common multiple sets is set and multiple first estimates of the first beam characteristic estimated from each of the common multiple sets using the first model 70. The model updating unit 68 can update the second model 90 using multiple second measurement values ​​of the second beam characteristic when each of the common multiple sets is set and multiple second estimates of the second beam characteristic estimated from each of the common multiple sets using the second model 90.

[0076] The model evaluation unit 66 may determine multiple sets of setting values ​​for multiple operational parameters to be used for evaluation in order to evaluate the validity of each of multiple models that use multiple common operational parameters as input. For example, the model evaluation unit 66 can simultaneously evaluate a third model and a fourth model for estimating the convergence / divergence angles in the x and y directions in addition to the first and second models for estimating the beam sizes in the x and y directions described above. The third model is used, for example, to estimate the convergence / divergence angle in the x direction, which is a third beam characteristic, using the first operational parameter Qa and the second operational parameter Qb as input. The fourth model is used, for example, to estimate the convergence / divergence angle in the y direction, which is a fourth beam characteristic, using the first operational parameter Qa and the second operational parameter Qb as input.

[0077] 7 to 11 show examples in which the beam characteristics have minimum values ​​in response to changes in the operating parameters, but the beam characteristics may have maximum values ​​in response to changes in the operating parameters. Also, while FIGS. 7 to 11 show examples in which the beam characteristics have extreme values ​​in response to changes in two operating parameters, the beam characteristics may have extreme values ​​in response to changes in one or three or more operating parameters. Also, while FIGS. 7 to 11 show examples in which the beam characteristics have linear extreme values ​​in response to changes in two operating parameters, the beam characteristics may have spot-like extreme values ​​in response to changes in the two operating parameters.

[0078] 12 is a flowchart showing an example of an ion implantation method according to an embodiment. Using a model for estimating beam characteristics, the automatic adjustment unit 60 determines a target set of setting values ​​for a plurality of operational parameters for generating an ion beam that satisfies desired beam characteristics (S50). The measurement control unit 62 measures the beam characteristics when the target set of operational parameters is set, and obtains measured values ​​(S52). If the measured values ​​satisfy the desired beam characteristics (Y in S54), the workpiece is irradiated with an ion beam that satisfies the desired beam characteristics (S56).

[0079] If the measured values ​​do not satisfy the desired beam characteristics (N in S54), the model evaluation unit 66 uses the model to determine multiple sets of setting values ​​for multiple operating parameters (S58). The estimation unit 64 uses the model to estimate multiple estimated values ​​of the beam characteristics from each of the multiple sets (S60). The measurement control unit 62 measures the beam characteristics when each of the multiple sets of operating parameters is set, and obtains multiple measured values ​​(S62). The model update unit 68 updates the model using the multiple measured values ​​and multiple estimated values ​​(S64). Thereafter, the processes of S50 to S56 are performed using the updated model.

[0080] Although the present invention has been described above with reference to the above-mentioned embodiments, the present invention is not limited to the above-mentioned embodiments, and suitable combinations or substitutions of the configurations of the embodiments are also included in the present invention. Furthermore, it is possible to suitably rearrange the combinations and processing orders in the embodiments based on the knowledge of those skilled in the art, and to make modifications such as various design changes to the embodiments, and such modified embodiments are also included in the scope of the present invention.

[0081] According to one aspect of the present invention, operating parameters can be adjusted quickly and accurately.

[0082] 10... ion source, 11... mass analyzer, 12... ion generator, 14... beam accelerator, 16... beam deflector, 18... beam transport device, 20... substrate transport and processing device, 23... beam measurement unit, 24... energy analysis electromagnet, 26... horizontal focusing quadrupole lens, 27... energy analysis slit, 28... first Faraday cup, 30... deflection electromagnet, 31... second Faraday cup, 32... beam shaper, 32a... first lens device, 32b... second lens device, 32c... third lens device device, 34...beam scanner, 36...beam collimator, 38...final energy filter, 39...Faraday cup, 40...implantation processing chamber, 41...beam monitor, 42...beam profiler, 50...central control unit, 50a...processor, 50b...memory, 50c...recording device, 52a, 52b...electrostatic quadrupole lens device, 60...automatic adjustment unit, 62...measurement control unit, 64...estimation unit, 66...model evaluation unit, 68...model update unit, 100...ion implantation device, 110...beam generation device.

Claims

1. An ion implantation apparatus comprising: a beam generating device configured to operate according to a plurality of operating parameters to generate an ion beam; an implantation processing chamber in which the ion beam is irradiated onto a workpiece; a measurement device for measuring beam characteristics of the ion beam; a memory storing a model for estimating the beam characteristics from a set of setting values ​​of the plurality of operating parameters and a predetermined program; and a processor for executing the predetermined program, wherein the processor updates the model in accordance with the predetermined program using a plurality of measured values ​​of the beam characteristics measured when each of a plurality of sets of setting values ​​of the plurality of operating parameters is set as the plurality of operating parameters, and a plurality of estimated values ​​of the beam characteristics estimated using the model from each of the plurality of sets; and using the updated model to determine a target set of setting values ​​of the plurality of operating parameters for generating an ion beam that satisfies desired beam characteristics.

2. The ion implantation apparatus according to claim 1, wherein the processor updates the model in accordance with the predetermined program so that the beam characteristics estimated from the updated model match the plurality of measured values ​​within a range including the plurality of sets.

3. The ion implantation apparatus according to claim 1, wherein said processor updates said model by linearly converting a set value of at least one of said plurality of operational parameters in accordance with said predetermined program.

4. The ion implantation apparatus according to claim 1, wherein said processor updates said model by linearly transforming said estimated values ​​of said beam characteristics in accordance with said predetermined program.

5. The ion implantation apparatus of claim 1, wherein the processor evaluates the validity of the model by comparing the multiple measured values ​​and the multiple estimated values ​​of the beam characteristics in accordance with the predetermined program, and if the processor evaluates that the model is invalid, updates the model using the multiple measured values ​​and the multiple estimated values ​​of the beam characteristics.

6. The ion implantation apparatus according to claim 5, wherein when the processor, in accordance with the predetermined program, evaluates that the model is valid, the processor does not update the model, and uses the model to determine the target set for generating an ion beam that satisfies desired beam characteristics.

7. The ion implantation apparatus according to claim 1, wherein said processor determines said plurality of sets using said model in accordance with said predetermined program.

8. The ion implantation apparatus according to claim 7, wherein the processor determines the plurality of sets in accordance with the predetermined program such that, within a range that includes the plurality of sets, there is an extreme value of the estimated value of the beam characteristics estimated from the model.

9. The ion implantation apparatus of claim 8, wherein the processor, in accordance with the predetermined program, calculates extreme values ​​of the measured values ​​of the beam characteristics in a range including the multiple sets from the multiple measured values ​​of the beam characteristics, and compares a first set of setting values ​​of the multiple operating parameters corresponding to the extreme values ​​of the measured values ​​of the beam characteristics with a second set of setting values ​​of the multiple operating parameters corresponding to the extreme values ​​of the estimated values ​​of the beam characteristics to evaluate the validity of the model.

10. The ion implantation apparatus of claim 8, wherein the processor, in accordance with the predetermined program, updates the model such that an extreme value of the estimated value of the beam characteristic estimated from the updated model exists at a first set of settings of the plurality of operational parameters corresponding to an extreme value of the measured value of the beam characteristic.

11. The ion implanter of claim 9, wherein said processor, in accordance with said predetermined program, further compares extreme values ​​of said measured values ​​and extreme values ​​of said estimated values ​​of said beam characteristics to assess the validity of said model.

12. The ion implantation apparatus according to claim 11, wherein the processor updates the model in accordance with the predetermined program so that, within a range including the plurality of sets, extreme values ​​of the estimated values ​​of the beam characteristics estimated from the updated model match extreme values ​​of the measured values ​​of the beam characteristics.

13. The ion implantation apparatus of claim 1, wherein the model includes a first model for estimating a first beam characteristic of the ion beam from the set of setting values ​​of the plurality of operational parameters, and a second model for estimating a second beam characteristic of the ion beam from the set of setting values ​​of the plurality of operational parameters, and the processor, in accordance with the predetermined program, updates the first model using a plurality of first measurement values ​​of the first beam characteristic measured when each of the plurality of sets is set as the plurality of operational parameters and a plurality of first estimates of the first beam characteristic estimated from each of the plurality of sets using the first model, and updates the second model using a plurality of second measurement values ​​of the second beam characteristic measured when each of the plurality of sets is set as the plurality of operational parameters, and a plurality of second estimates of the second beam characteristic estimated from each of the plurality of sets using the second model.

14. The ion implantation apparatus according to claim 13, wherein the processor determines the plurality of sets in accordance with the predetermined program such that, within a range including the plurality of sets, there exists an extreme value of the estimated value of the first beam characteristic estimated from the first model, and there exists an extreme value of the estimated value of the second beam characteristic estimated from the second model.

15. An ion implantation apparatus according to any one of claims 1 to 14, characterized in that the beam generating device includes a lens device that applies at least one of an electric field and a magnetic field to the ion beam to converge or diverge the ion beam, the beam characteristics include at least one of a beam size and a convergence / divergence angle of the ion beam, and the multiple operating parameters include two or more operating parameters for controlling the operation of the lens device.

16. A method for ion implantation comprising: measuring a plurality of measured values ​​of beam characteristics of an ion beam generated by a beam generating device configured to operate in accordance with a plurality of operating parameters to generate an ion beam, when a plurality of sets of setting values ​​of the plurality of operating parameters are set as the plurality of operating parameters; estimating a plurality of estimated values ​​of the beam characteristics corresponding to each of the plurality of sets using a model for estimating the beam characteristics from the set of setting values ​​of the plurality of operating parameters; updating the model using the plurality of measured values ​​and the plurality of estimated values ​​of the beam characteristics; determining a target set of setting values ​​of the plurality of operating parameters for generating an ion beam satisfying desired beam characteristics, using the updated model; and irradiating a workpiece with the ion beam generated by the beam generating device when the target set is set as the plurality of operating parameters.

Images