Ion implantation apparatus and ion implantation method

Abstract

To make adjustment of beam energy be quick.SOLUTION: On the basis of a first data set for making beam energy of an ion beam IB to be output from a high energy multistage linear acceleration unit be a first output value, an ion implantation apparatus determines a second data set for making the beam energy be a second output value. The high energy multistage linear acceleration unit comprises a plurality of linear accelerators 22a to 22c. Each of the plurality of linear accelerators 22a to 22c includes a plurality of stages of high frequency acceleration sections. Acceleration phases of the respective stages of high frequency acceleration sections in the first data set are equal to those of corresponding stages of high frequency acceleration sections in the second data set. A voltage amplitude of at least one stage of the plurality of stages of high frequency acceleration sections in the first data set is different from that of a corresponding stage of the plurality of stages of high frequency acceleration sections in the second data set.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] In the semiconductor manufacturing process, a process of implanting ions into semiconductor wafers (also called the ion implantation process) is standard for the purpose of changing the conductivity of the semiconductor, changing the crystal structure of the semiconductor, etc. The equipment used in the ion implantation process is called an ion implanter. The implantation energy of the ions is determined according to the desired implantation depth of the ions implanted near the surface of the wafer. A high-energy ion beam (e.g., 1 MeV or higher) is used for implanting into relatively deep regions.

[0003] In ion implanters capable of outputting high-energy ion beams, the ion beam is accelerated using a multi-stage radio frequency linear accelerator (LINAC), where the radio frequency parameters such as voltage amplitude, frequency and phase of each stage are adjusted to obtain the desired beam energy. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-085179 A Summary of the Invention [Problem to be solved by the invention]

[0005] Recently, ultra-high energy ion beams (e.g., 4 MeV or more) are required for implantation into deeper regions. To be able to output ultra-high energy ion beams, it is necessary to increase the number of stages in the radio frequency linear accelerator compared to conventional systems. As the number of stages in the radio frequency linear accelerator increases, the time required to adjust the radio frequency parameters increases accordingly, leading to a decrease in the productivity of the ion implantation system.

[0006] It is an exemplary object of some aspects of the present invention to provide a technique for speeding up beam energy adjustment. [Means for solving the problem]

[0007] An ion implantation apparatus according to one embodiment of the present invention comprises a high-energy multi-stage linear acceleration unit having a plurality of linear accelerators, each of which has a plurality of stages of radio frequency acceleration sections, and a control device that controls the operation of the high-energy multi-stage linear acceleration unit according to a data set that defines the voltage amplitude, frequency and phase of each stage of the radio frequency acceleration sections of each of the plurality of linear accelerators. The control device is configured to acquire a first data set for setting the beam energy of the ion beam output from the high-energy multi-stage linear acceleration unit to a first output value, determine a second data set based on the first data set for setting the beam energy of the ion beam output from the high-energy multi-stage linear acceleration unit to a second output value different from the first output value, and operate the high-energy multi-stage linear acceleration unit according to the determined second data set, wherein the acceleration phase of each stage of the high frequency acceleration section of at least one linear accelerator among the multiple linear accelerators is the same between the first data set and the second data set in all of the multiple stages of the high frequency acceleration section of the at least one linear accelerator, and the voltage amplitude of each stage of the high frequency acceleration section of the at least one linear accelerator is different between the first data set and the second data set in at least one of the multiple stages of the high frequency acceleration section of the at least one linear accelerator.

[0008] Another aspect of the present invention is a method for ion implantation using an ion implantation apparatus including a high-energy multi-stage linear acceleration unit. The high-energy multi-stage linear acceleration unit includes a plurality of linear accelerators, each of which has a plurality of radio frequency acceleration stages and is configured to operate according to a data set that defines a voltage amplitude, a frequency, and a phase of the radio frequency acceleration stages. The ion implantation method includes acquiring a first data set for setting a beam energy of an ion beam output from the high-energy multi-stage linear acceleration unit to a first output value, determining a second data set based on the first data set for setting a beam energy of the ion beam output from the high-energy multi-stage linear acceleration unit to a second output value different from the first output value, and irradiating a wafer with the ion beam output from the high-energy multi-stage linear acceleration unit operating according to the second data set to implant ions. The acceleration phase of each stage of the high frequency acceleration section of at least one of the multiple linear accelerators is the same between the first data set and the second data set in all of the multiple stages of the high frequency acceleration section of the at least one linear accelerator, and the voltage amplitude of each stage of the high frequency acceleration section of the at least one linear accelerator is different between the first data set and the second data set in at least one of the multiple stages of the high frequency acceleration section of the at least one linear accelerator.

[0009] 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 as aspects of the present invention. Effect of the Invention

[0010] According to the present invention, the beam energy can be adjusted quickly, and ion implantation processing using ion beams having various beam energies can be easily realized. [Brief description of the drawings]

[0011] [Figure 1] 1 is a top view showing a schematic configuration of an ion implantation apparatus according to an embodiment; [Diagram 2] 2(a) to (c) are cross-sectional views showing the configuration of a linear accelerator. [Diagram 3] 3(a) and (b) are front views showing a schematic configuration of the electrostatic quadrupole lens device. [Figure 4] FIG. 2 is a cross-sectional view showing a schematic configuration of a radio frequency acceleration part. [Diagram 5] 4 is a graph showing a schematic example of a time waveform of a high-frequency voltage and acceleration / deceleration energy received by an ion particle. [Figure 6] 4 is a graph showing a schematic example of a time waveform of a high-frequency voltage and acceleration / deceleration energy received by an ion particle. [Figure 7] 4 is a graph showing a schematic example of a time waveform of a high-frequency voltage and acceleration / deceleration energy received by an ion particle. [Figure 8] 8(a) and (b) are graphs showing schematic examples of acceleration and deceleration energy received by bunched ion particles. [Figure 9] 4 is a flowchart showing a flow of a first adjustment method. [Figure 10] 13 is a flowchart showing a flow of a second adjustment method. [Figure 11] 10 is a graph showing an example of an error in the energy of an ion beam obtained from a second data set. [Figure 12] 11 is a graph showing a change in beam current of an ion beam obtained by a second data set. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, the 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 descriptions are omitted as appropriate. In addition, the configurations described below are examples, and do not limit the scope of the present invention in any way.

[0013] Before describing the embodiments in detail, an overview will be given. The present embodiment relates to a high-energy ion implantation device. The ion implantation device accelerates an ion beam generated in an ion source by a radio-frequency linear accelerator, transports the high-energy ion beam obtained by the acceleration along a beam line to a workpiece (e.g., a substrate or a wafer), and implants ions into the workpiece.

[0014] In the present embodiment, "high energy" refers to an ion beam having a beam energy of 1 MeV or more, 4 MeV or more, or 10 MeV or more. High energy ion implantation implants desired impurity ions into the wafer surface with relatively high energy, so that the desired impurity can be implanted into deeper regions of the wafer surface (e.g., to a depth of 5 μm or more). Applications of high energy ion implantation include, for example, forming P-type and / or N-type regions in the manufacture of semiconductor devices such as advanced image sensors.

[0015] In order to realize the desired beam conditions in an ion implantation apparatus, it is necessary to appropriately set the operating parameters of the various devices constituting the ion implantation apparatus. In order to obtain an ion beam having the desired beam energy, it is necessary to appropriately set the operating parameters of the multi-stage high frequency acceleration units. In addition, there are lens devices for appropriately transporting the ion beam on the upstream and downstream sides of the high frequency acceleration units of each stage, and in order to obtain an ion beam having the desired beam current, it is necessary to appropriately set the operating parameters of the multi-stage lens devices. Furthermore, in order to adjust the beam quality such as the parallelism and angular distribution of the ion beam irradiated to the wafer, it is necessary to appropriately set the operating parameters of the various devices downstream of the linear accelerator. A set of these operating parameters is generated as a "data set" for realizing the desired beam conditions.

[0016] To generate a higher energy ion beam, a linear accelerator with more RF accelerator stages is required. As the number of RF accelerator stages increases, the number of operating parameters to be adjusted increases, and the time required to generate an appropriate data set increases. In some semiconductor manufacturing processes, multi-stage implantation is required in which multiple ion beams having different beam energies are irradiated onto the same wafer. In this case, multiple data sets corresponding to the multiple beam energies must be generated. If multiple data sets are generated from scratch, it would take a very long time to generate all of the multiple data sets. This would lead to a decrease in the productivity of the ion implantation device.

[0017] In this embodiment, a second data set for obtaining an ion beam having a beam energy different from that of the first data set can be quickly generated based on an existing first data set. Specifically, the voltage amplitude of at least one stage of the multi-stage RF acceleration unit is changed while the acceleration phase of the multi-stage RF acceleration unit is fixed, thereby saving labor in adjusting the beam energy. In addition, the operation parameters of the multi-stage lens device included in the linear accelerator are changed under certain conditions, thereby saving labor in generating a second data set that realizes beam transport equivalent to that of the first data set. Furthermore, the operation parameters of various devices downstream of the linear accelerator are also changed under certain conditions, thereby saving labor in generating a second data set that realizes beam quality equivalent to that of the first data set.

[0018] 1 is a top view showing a schematic configuration of an ion implantation apparatus 100 according to an embodiment of the present invention, which includes a beam generating unit 12, a beam acceleration unit 14, a beam deflection unit 16, a beam transport unit 18, and a substrate transfer processing unit 20.

[0019] The beam generating unit 12 has an ion source 10 and a mass analyzer 11. In the beam generating unit 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 acceleration unit 14.

[0020] The beam acceleration unit 14 includes a plurality of linear accelerators 22a, 22b, and 22c for accelerating 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 of the beam acceleration unit 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 measures beam characteristics of the ion beam, such as beam energy, beam current, and beam profile. In this specification, the beam acceleration unit 14 is also referred to as a "high energy multi-stage linear acceleration unit."

[0021] 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 acceleration unit 14 and includes a multi-stage (e.g., 5 to 15 stages) high-frequency acceleration section. The first linear accelerator 22a performs "bunching" to match a continuous beam (DC beam) output from the beam generating unit 12 to 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 acceleration unit 14 and includes a multi-stage (e.g., 5 to 15 stages) high-frequency acceleration section. 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 acceleration unit 14 and includes a multi-stage (e.g., 5 to 15 stages) high-frequency acceleration section. 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.

[0022] The high-energy ion beam output from the beam acceleration unit 14 has a certain range of energy distribution. Therefore, in order to perform reciprocating scanning and parallelization of the high-energy ion beam downstream of the beam acceleration unit 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.

[0023] The beam deflection unit 16 performs energy analysis, energy dispersion control, and trajectory correction of the high-energy ion beam output from the beam acceleration unit 14. The beam deflection unit 16 constitutes a portion of the beamline BL that extends in an arc shape. The high-energy ion beam is deflected by the beam deflection unit 16 and directed toward the beam transport unit 18.

[0024] The beam deflection unit 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 deflection 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). Moreover, a 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 an "energy analyzing device."

[0025] 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 so that the slit width is variable by, for example, being composed of two shields movable in the slit width direction and 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 having different slit widths.

[0026] 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 for measuring the beam current of the ion beam that is orbitally corrected and enters the beam transport unit 18. Each of the first Faraday cup 28 and the second Faraday cup 31 is configured to be capable of being moved in and out of the beamline BL by the operation of a Faraday cup driver (not shown).

[0027] The beam transport unit 18 constitutes another linearly extending portion of the beamline BL, and runs parallel to the beam acceleration unit 14 across the maintenance area MA in the center of the device. The length of the beam transport unit 18 is designed to be approximately the same as the length of the beam acceleration unit 14. As a result, the beamline BL, which is composed of the beam acceleration unit 14, the beam deflection unit 16, and the beam transport unit 18, forms a U-shaped layout overall.

[0028] The beam transport unit 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, 39R.

[0029] 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 unit 16 into a desired cross-sectional shape. The beam shaper 32 includes, for example, an electric field type triple-stage quadrupole lens (also called a triplet Q lens) and has three electrostatic quadrupole lens devices. The beam shaper 32 can independently adjust the convergence or divergence of the ion beam in the horizontal direction (x direction) and the vertical direction (y direction) by using the three lens devices. The beam shaper 32 may include a magnetic field type lens device, or may include a lens device that uses both an electric field and a magnetic field to shape the beam.

[0030] 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 pair of scanning electrodes is connected to a variable voltage power supply (not shown), and the voltage applied between the pair of scanning electrodes is periodically changed to change the electric field generated between the electrodes and deflect the ion beam at various angles. As a result, the ion beam is scanned over a scanning range indicated by an 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 scanner, and the beam scanner 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, thereby 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 toward the beam dump 35, thereby blocking the ion beam so that it does not reach the downstream substrate transport processing unit 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 beamline BL. The beam collimator 36 has a plurality of arc-shaped collimating lens electrodes with a slit for passing the ion beam at the center. The collimating lens electrodes are connected to a high-voltage power supply (not shown), and an electric field generated by applying a voltage acts on the ion beam to align the traveling direction of the ion beam in parallel. 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 utilizes 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 processing unit 20. The final energy filter 38 is sometimes called an angular energy filter (AEF) and has an AEF electrode pair 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.

[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 enter. The left and right Faraday cups 39L, 39R are provided at positions that do not block the beam heading toward the wafer W, and measure the beam current during ion implantation into the wafer W.

[0035] A substrate transport processing unit 20 is provided downstream of the beam transport unit 18, that is, at the most downstream of the beam line BL. The substrate transport processing unit 20 has an implantation processing chamber 40, a beam monitor 41, a beam profiler 42, a profiler driving device 43, a substrate transport 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 measures beam current, beam parallelism, and the like as beam characteristics. 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 driving device 43, and is retreated from the implantation position where the wafer W is located during ion implantation, and is inserted into the implantation position when the wafer W is not at the implantation position. The 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 a plurality of Faraday cups arranged in an array in the x direction so that the beam current at a plurality of positions in the beam scanning direction (x direction) can be measured simultaneously.

[0038] Beam profiler 42 may include a single Faraday cup for measuring the amount of beam current, or may include an angle measuring device for measuring angle information of the beam. The angle measuring device may include, for example, a slit and multiple current detectors provided away from the slit in the beam traveling direction (z direction). The angle measuring device may measure the angle component of the beam in the slit width direction, for example, by measuring the beam that has passed through the slit with multiple current detectors arranged in the slit width direction. Beam profiler 42 may include a first angle measuring device capable of measuring angle information in the x direction, and a second angle measuring device capable of measuring angle information in the y direction.

[0039] The substrate transport device 44 is configured to transport the wafer 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 a plurality of wafer containers 45, and has, for example, four mounting stages arranged in the x direction. A wafer container transport 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 the load port 46 through the wafer container transport port by a transport robot installed, for example, on the ceiling or the like in a semiconductor manufacturing factory in which the ion implantation device 100 is installed, and is automatically unloaded from the load port 46.

[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 an input device for setting operation parameters of the ion implantation apparatus 100 is provided near the central controller 50. The positions of the control panel 49 and the central controller 50 are not particularly limited, but for example, the control panel 49 and the central controller 50 can be disposed adjacent to an entrance / exit 48 of a maintenance area MA between the beam generating unit 12 and the substrate transport processing unit 20. By locating the ion source 10, the load port 46, the control panel 49, and the central controller 50, which are frequently operated by the operator managing the ion implantation apparatus 100, adjacent to each other, work efficiency can be improved.

[0042] Next, the configuration of the beam acceleration unit 14 will be described in detail. Figures 2(a) to 2(c) are cross-sectional views showing the configuration of the linear accelerators 22a to 22c. Figure 2(a) shows the configuration of the first linear accelerator 22a, Figure 2(b) shows the configuration of the second linear accelerator 22b, and Figure 2(c) shows the configuration of the third linear accelerator 22c. The linear accelerators 22a to 22c include multiple stages of RF accelerators 101 to 115 and multiple stages of electrostatic quadrupole lens devices 120a, 120b, 120c, and 121 to 135, and the RF accelerators and electrostatic quadrupole lens devices of each stage are alternately arranged along the beamline BL.

[0043] The RF accelerator applies a RF voltage V to the RF electrode through which the ion beam IB passes. RF The ion particles that make up the ion beam IB are accelerated or decelerated by applying a radio frequency voltage V RF The voltage amplitude V0, frequency f, and phase φ of the high frequency voltage V RF The voltage amplitude V0, frequency f, and phase φ of the

[0044] The electrostatic quadrupole lens device includes a lens electrode for applying an electrostatic field to the ion beam IB to converge or diverge the ion beam IB, and ground electrodes provided on the upstream and downstream sides of the lens electrode. The electrostatic quadrupole lens device functions as a horizontal convergent (vertical divergent) lens that converges the beam in the x direction, or a vertical convergent (horizontal divergent) lens that converges the beam in the y direction, by switching the positive and negative voltages applied to the lens electrodes.

[0045] 2(a) to (c) show the lens electrodes facing in the y direction, and omit the lens electrodes facing in the x direction. When a negative voltage is applied to the lens electrodes facing in the y direction, they function as horizontally converging (vertical diverging) lenses. Conversely, when a positive voltage is applied to the lens electrodes facing in the y direction, they function as vertically converging (horizontally diverging) lenses. The configuration of the lens electrodes will be described separately later with reference to FIGS. 3(a) and (b).

[0046] The first linear accelerator 22a includes five stages of RF acceleration units 101, 102, 103, 104, and 105, and six stages of electrostatic quadrupole lens devices 120a, 121, 122, 123, 124, and 125. Each of the first to fifth stages of electrostatic quadrupole lens devices 121 to 125, excluding the electrostatic quadrupole lens device 120a provided at the entrance of the first linear accelerator 22a, is disposed downstream of the corresponding stage of the first to fifth stages of the RF acceleration units 101 to 105.

[0047] Six-stage electrostatic quadrupole lens assemblies 120a, 121-125 provided in the first linear accelerator 22a are arranged such that horizontal converging lenses and vertical converging lenses alternate along the beamline BL. For example, the entrance, second-stage, and fourth-stage electrostatic quadrupole lens assemblies 120a, 122, and 124 of the first linear accelerator 22a are horizontal converging lenses, and the first-stage, third-stage, and fifth-stage electrostatic quadrupole lens assemblies 121, 123, and 125 are vertical converging lenses.

[0048] The second linear accelerator 22b includes five stages of RF acceleration units 106, 107, 108, 109, and 110, and six stages of electrostatic quadrupole lens devices 120b, 126, 127, 128, 129, and 130. Each of the sixth to tenth stages of electrostatic quadrupole lens devices 126-130, excluding the electrostatic quadrupole lens device 120b provided at the entrance of the second linear accelerator 22b, is disposed downstream of the corresponding stage of the sixth to tenth stages of the RF acceleration units 106-110. The six stages of electrostatic quadrupole lens devices 120b, 126-130 provided in the second linear accelerator 22b are disposed such that horizontal converging lenses and vertical converging lenses alternate along the beamline BL. For example, the entrance of the second linear accelerator 22b, the seventh stage and the ninth stage electrostatic quadrupole lens assemblies 120b, 127, 129 are horizontal converging lenses, and the sixth stage, eighth stage and tenth stage electrostatic quadrupole lens assemblies 126, 128, 130 are vertical converging lenses.

[0049] The third linear accelerator 22c includes five stages of RF acceleration units 111, 112, 113, 114, and 115, and six stages of electrostatic quadrupole lens devices 120c, 131, 132, 133, 134, and 135. Each of the eleventh to fifteenth stages of electrostatic quadrupole lens devices 131-135, excluding the electrostatic quadrupole lens device 120c provided at the entrance of the third linear accelerator 22c, is disposed downstream of the corresponding stage of the eleventh to fifteenth stages of the RF acceleration units 111-115. The six stages of electrostatic quadrupole lens devices 120c, 131-135 provided in the third linear accelerator 22c are disposed such that horizontal converging lenses and vertical converging lenses alternate along the beamline BL. For example, the electrostatic quadrupole lens assemblies 120c, 132, and 134 at the entrance of the third linear accelerator 22c and the twelfth and fourteenth stages are horizontal converging lenses, and the electrostatic quadrupole lens assemblies 131, 133, and 135 at the eleventh, thirteenth, and fifteenth stages are vertical converging lenses.

[0050] The number of stages of the RF acceleration section and electrostatic quadrupole lens device included in the linear accelerators 22a to 22c is not limited to that shown in the figure, and may be different from the example shown in the figure. The arrangement of the electrostatic quadrupole lens device may be different from the example shown in the figure. For example, at least one stage of the electrostatic quadrupole lens device may have one pair of a horizontal converging lens and a vertical converging lens, or may have multiple pairs of a horizontal converging lens and a vertical converging lens.

[0051] 3(a) and (b) are front views showing the schematic configurations of the electrostatic quadrupole lens devices 52a and 52b as viewed from the upstream side of the beamline. The electrostatic quadrupole lens device 52a in Fig. 3(a) is a horizontal focusing lens that focuses the ion beam IB in the horizontal direction (x direction), and the electrostatic quadrupole lens device 52b in Fig. 3(b) is a vertical focusing lens that focuses the ion beam IB in the vertical direction (y direction).

[0052] The electrostatic quadrupole lens device 52a in FIG. 3(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 have a negative potential, and a repulsive force between the upper and lower lens electrodes 54a, which have a positive potential, and the left and right lens electrodes 56a, which have a positive potential, for the ion beam IB, which is composed of ion particles having a positive charge. As a result, the electrostatic quadrupole lens device 52a adjusts the beam shape so that the ion beam B converges in the x direction and diverges in the y direction.

[0053] The electrostatic quadrupole lens device 52b in Fig. 3(b) 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), similar to Fig. 3(a). In Fig. 3(b), the positive and negative potentials of the applied potentials are reversed from those in Fig. 3(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 adjusts the beam shape so that the ion beam B converges in the y direction and diverges in the x direction.

[0054] FIG. 4 is a cross-sectional view showing a schematic configuration of the radio frequency acceleration section 70, and shows the configuration of one stage of the radio frequency acceleration section included in each of the linear accelerators 22a to 22c. The radio frequency acceleration section 70 includes a radio frequency electrode 72, a radio frequency resonator 74, a stem 76, and a radio frequency power supply 78. The radio frequency electrode 72 is a hollow cylindrical electrode body, and the ion beam IB passes through the inside of the electrode body. The radio frequency electrode 72 is connected to the radio frequency resonator 74 via the stem 76. The radio frequency power supply 78 supplies a radio frequency voltage V RF The central control device 50 controls the high-frequency resonator 74 and the high-frequency power supply 78 to supply the high-frequency voltage V applied to the high-frequency electrode 72. RF The voltage amplitude V0, frequency f and phase φ of the

[0055] Electrostatic quadrupole lens devices 52a, 52b are provided on the upstream and downstream sides of the RF accelerator 70. The upstream electrostatic quadrupole lens device 52a has a first ground electrode 60a, a second ground electrode 62a, upper and lower lens electrodes 54a, left and right lens electrodes 56a, and a lens power supply 58a (see FIG. 3). The upper and lower lens electrodes 54a and the left and right lens electrodes 56a are provided between the first ground electrode 60a and the second ground electrode 62a. The downstream electrostatic quadrupole lens device 52b has a first ground electrode 60b, a second ground electrode 62b, upper and lower lens electrodes 54b, left and right lens electrodes 56b, and a lens power supply 58b (see FIG. 3). The upper and lower lens electrodes 54b and the left and right lens electrodes 56b are provided between the first ground electrode 60b and the second ground electrode 62b.

[0056] In the example of Fig. 4, the upstream electrostatic quadrupole lens device 52a is a horizontal converging (vertical diverging) lens, and the downstream electrostatic quadrupole lens device 52b is a vertical converging (vertical diverging) lens. Depending on which stage the RF acceleration section 70 is, the upstream electrostatic quadrupole lens device 52a may be a vertical converging (horizontal diverging) lens, and the downstream electrostatic quadrupole lens device 52b may be a horizontal converging (vertical diverging) lens. The horizontal and vertical convergence can be changed by reversing the positive and negative of the voltages applied by the lens power supplies 58a and 58b.

[0057] 4 accelerates or decelerates ion particles 86 that constitute the ion beam IB by utilizing a potential difference between an upstream gap 80 between the radio frequency electrode 72 and the upstream second ground electrode 62a, and a downstream gap 82 between the radio frequency electrode 72 and the downstream first ground electrode 60b. For example, a radio frequency voltage V RF By adjusting the phase φ, it is possible to accelerate the ion particles 86 passing through the radio frequency acceleration unit 70. Note that since the inside of the radio frequency electrode 72 is substantially at an equipotential potential, the ion particles 86 are not substantially accelerated or decelerated when passing through the inside of the radio frequency electrode 72.

[0058] Figure 5 shows the high-frequency voltage V RF 1 is a graph showing an example of a time waveform of the high-frequency voltage V at time t2 when the ion particle 86 passes through the center 84 of the high-frequency electrode 72, and an example of the acceleration / deceleration energy received by the ion particle 86. Time t1 is the timing when the ion particle 86 passes through the upstream gap 80, time t2 is the timing when the ion particle 86 passes through the center 84 of the high-frequency electrode 72, and time t3 is the timing when the ion particle 86 passes through the downstream gap 82. In this specification, the high-frequency voltage V at time t2 when the ion particle 86 passes through the center 84 of the high-frequency electrode 72 is RF The phase φ of the high frequency voltage V is also called the "acceleration phase φ0". The acceleration phase φ0 is a relative phase based on the timing of the passage of the ion particle 86. RF Although it is different from the phase (absolute phase) φ, the value of the acceleration phase φ0 can be controlled by adjusting the phase φ. When the acceleration phase φ0 changes, the amount of acceleration / deceleration energy that the ion particle 86 receives from the RF accelerator 70 changes. Therefore, the acceleration phase φ0 is one of the important parameters in controlling the value of the beam energy.

[0059] 5 shows a case where the acceleration phase is set to φ0=0°. In this case, at time t1 when the ion particle 86 passes through the upstream gap 80, the high frequency voltage V RF is a negative value (-VA At time t1, the potential of the high-frequency electrode 72 (-V A ), the potential (0 V) of the second ground electrode 62a upstream is higher than that of the ion particle 86. A At time t3 when the ion particle 86 passes through the downstream gap 82, the acceleration energy due to the high frequency voltage V RF is a positive value (+V A At time t3, the potential of the high-frequency electrode 72 (+V A ) is high, so the potential difference V A As a result, the ion particle 86 receives an acceleration energy due to a total of 2 V A The acceleration energy corresponds to the voltage of

[0060] FIG. 6 shows the case where the acceleration phase is set to φ0=-45°. RF , and the phase difference Δφ from the upstream gap 80 to the downstream gap 82. gap is the same as in FIG. 5. As a result of the acceleration phase φ0 being shifted by -45°, the potential difference V B1 The acceleration energy due to the potential difference V B2 The acceleration energy due to is given by V B1 +V B2 This acceleration energy corresponds to a voltage of 2V in the example shown in Figure 5. A This is smaller than the acceleration energy corresponding to the voltage.

[0061] FIG. 7 shows the case where the acceleration phase is set to φ0=-90°. RF , and the phase difference Δφ from the upstream gap 80 to the downstream gap 82. gap is the same as in FIG. 5. As a result of the acceleration phase φ being shifted by -90°, the potential difference V CWhile the acceleration energy due to the potential difference -V C The deceleration energy due to is given. As a result, the total acceleration / deceleration energy obtained is 0.

[0062] The acceleration / deceleration energy ΔE given by one stage of the high-frequency acceleration unit 70 is RF The voltage amplitude V0, the acceleration phase φ0, and the phase difference Δφ from the upstream gap 80 until the ion particle 86 reaches the downstream gap 82. gap According to the knowledge of the present inventors, the acceleration / deceleration energy ΔE can be approximated by the following formula (1). ΔE≒qV0·α(E)sin(Δφ gap / 2)sin(φ0) …(1) Here, q is the charge of the ion particle 86, and α(E) is a coefficient that depends on the energy E of the ion particle 86. gap is the electrode length L0 of the high frequency electrode 72, the gap length L1 of the upstream gap 80, the gap length L2 of the downstream gap 82, the passing velocity of the ions (average velocity v), and the high frequency voltage V RF The phase difference Δφ is determined by the frequency f of gap Roughly speaking, this corresponds to the transit time τ≈(L0+L1 / 2+L2 / 2) / v from the upstream gap 80 to the downstream gap 82. The transit speed (average speed v) of the ion particle 86 is determined by the mass m and energy E of the ion particle 86.

[0063] From the above formula (1), it can be seen that by adjusting at least one of the voltage amplitude V0 and the acceleration phase φ0 of the radio frequency acceleration section 70, it is possible to adjust the acceleration / deceleration energy ΔE that the radio frequency acceleration section 70 imparts to the ion particles 86. Therefore, by adjusting at least one of the voltage amplitude V0 and the acceleration phase φ0 of each of the multiple stages of radio frequency acceleration sections 101-115, it is possible to adjust the final beam energy of the ion beam output from the beam acceleration unit 14.

[0064] 8(a) and (b) are graphs showing an example of acceleration and deceleration energy received by a bunched ion particle group 90. The beam acceleration unit 14 accelerates the bunched ion particle group 90 to a specific acceleration phase. Ideally, the ion particle group 90 does not have a spatial spread in the beam traveling direction, but in reality, the ion particle group 90 has a spatial spread. As a result, the first ion particle 91 located near the center of the ion particle group 90, the second ion particle 92 located near the front of the ion particle group, and the third ion particle 93 located near the rear end of the ion particle group have a high frequency voltage V RF The potential differences V1, V2, V3 received by the ion particles 91-93 are different. When the potential differences V1, V2, V3 received by the ion particles 91-93 are different, the acceleration energy received by the ion particles 91-93 may be different. As a result, the energy distribution of the ion particle group 90 may change before and after passing through the RF acceleration unit 70.

[0065] Figure 8(a) shows the high-frequency voltage V RF This figure shows a case where the acceleration / deceleration energy ΔE received by the ion particle group 90 is adjusted by changing the voltage amplitude V0 of the ion particle group 90 by a factor of a. The curve shown by the dashed line is the high-frequency voltage waveform V0cos(ωt+φ0) before adjustment, and the curve shown by the solid line is the high-frequency voltage waveform aV0cos(ωt+φ0) after adjustment. Here, ω is the high-frequency voltage V RF and ω=2πf. Since the potential differences received by the ion particles 91-93 are all a times greater after the adjustment, the acceleration energy received by each of the ion particles 91-93 can be changed linearly. As a result, the change in the energy distribution of the ion particle group 90 before and after passing through the RF acceleration unit 70 is substantially the same before and after the adjustment, and the transport state of the ion particle group 90 is also substantially the same before and after the adjustment. As a result, it is possible to change only the beam energy while maintaining the same beam quality before and after the adjustment.

[0066] Figure 8(b) shows the high-frequency voltage V RF The acceleration phase φ0 of aThe dashed curve indicates the high-frequency voltage waveform V0cos(ωt+φ0) before adjustment, and the solid curve indicates the high-frequency voltage waveform V0cos(ωt+φ0+φ) after adjustment. a 8(a), the potential difference received by the first ion particle 91 is a times as large as that in FIG. 8(a) after the adjustment. However, the potential differences received by the second ion particle 92 and the third ion particle 93 are not a times as large as that in FIG. 8(a), but are b times as large as that in FIG. 8(a), and are c times as large as that in FIG. 8(a), respectively, so that the acceleration energy received by each of the ion particles 91 to 93 changes nonlinearly. As a result, the change in the energy distribution of the ion particle group 90 before and after passing through the RF acceleration section 70 differs between before and after the adjustment. As a result, it is difficult to equalize the transport state and the beam quality before and after the adjustment.

[0067] In this embodiment, the beam energy adjustment methods used are a first adjustment method in which the acceleration phase φ0 is variable, and a second adjustment method in which the acceleration phase φ0 is fixed. The first adjustment method is used when generating a new data set, etc. The second adjustment method is used when fine-tuning the beam energy based on an existing data set, etc. In the second adjustment method, the acceleration phase φ0 is fixed, so that it is possible to adjust essentially only the beam energy while maintaining the same beam transport state as the existing data set.

[0068] 9 is a flowchart showing the flow of the first adjustment method. First, based on desired beam conditions, initial values ​​(initial parameters) of the operating parameters of various devices constituting the ion implantation apparatus 100 are calculated (S10). As the initial parameters, RF parameters for each of the multiple stages of RF acceleration units 101-115 and lens parameters that determine the applied voltages for each of the multiple stages of electrostatic quadrupole lens devices 120a-120c, 121-135 are calculated.

[0069] The values ​​of the radio frequency parameters and the lens parameters are calculated by setting a target beam energy and performing a simulation using a predetermined algorithm. For example, appropriate radio frequency parameters are set for a simulation model simulating the beam optical system of the beam acceleration unit 14, and the value of the output energy is calculated while changing the value of the radio frequency parameter. In this way, the radio frequency parameters for obtaining the target beam energy are calculated. In addition, the lens parameters for maximizing the transport efficiency are calculated by calculating the transport state of the ion beam IB while changing the value of the lens parameter. The state in which the transport efficiency of the ion beam IB is maximized refers to a state in which the proportion of the beam that collides with the radio frequency electrodes 72 and the lens electrodes 54a, 54b, 56a, and 56b of each stage and is lost is minimized.

[0070] Next, the calculated initial parameters are set in the various devices constituting the ion implantation apparatus 100 to generate the ion beam IB (S12). Next, the beam energy of the generated ion beam IB is measured, and the radio frequency parameters are adjusted based on the measured beam energy value, so that the beam energy becomes a target value (S14). Even if the beam acceleration unit 14 is operated based on the initial parameters obtained by simulation, the desired beam energy is not necessarily obtained, and therefore the adjustment in S14 is necessary. There are several possible reasons why the adjustment is necessary, including, for example, a manufacturing error or installation error of the radio frequency electrode 72, or an error in the radio frequency voltage V applied to the radio frequency electrode 72. RF These include amplitude, frequency and phase errors.

[0071] In the adjustment in S14, for example, the adjusted radio frequency parameters are calculated by a simulation using the same algorithm as in S10. For example, the difference between the measured value and the target value of the beam energy is reflected in a simulation model, and the radio frequency parameters in which the difference has been corrected are calculated. Note that fine-tuning of the radio frequency parameters is not easy, and in many cases, it is necessary to repeatedly measure the beam energy and perform a time-consuming simulation.

[0072] When the desired beam energy is obtained in S14, the beam current of the generated ion beam IB is measured, and the lens parameters are adjusted based on the measured beam current to adjust the beam current (S16). For example, the lens parameters of the electrostatic quadrupole lens device of each stage are adjusted so that the transport efficiency of the ion beam IB by the beam acceleration unit 14 is maximized. By maximizing the transport efficiency of the ion beam IB, the beam current of the ion beam IB output from the beam acceleration unit 14 can be maximized. Note that fine adjustment of the lens parameters is not easy, and it is necessary to repeat fine adjustment of the lens parameters of multiple stages while measuring the beam current. When the beam current is insufficient for the target value, or conversely, when the beam current is too high, the parameters of the ion source 10 may be adjusted.

[0073] When the desired beam current amount is obtained in S16, the beam quality is measured downstream of the beam acceleration unit 14, and the operating parameters of various devices are adjusted based on the measured beam quality, so that the beam quality is adjusted to a target value (S18). The beam quality adjusted in S18 is, for example, the beam size, beam parallelism, and beam angle. The beam size can be adjusted, for example, by changing the parameters of the converging / diverging lens included in the beam shaper 32. The beam parallelism can be adjusted, for example, by changing the parameters of the collimating lens included in the beam collimator 36. The beam angle in the x direction can be adjusted by changing the parameters of the deflection electromagnet 30.

[0074] When the desired beam quality is obtained in S18, a set of operational parameters set for various devices of the ion implantation apparatus 100 is stored as a data set (S20), thereby creating a first data set for realizing the desired beam conditions.

[0075] The first adjustment method for generating the first data set includes adjustment steps S14, S16, and S18, and therefore often takes a long time to obtain an optimal data set. Each step S10 to S20 in the first adjustment method can be executed by an automatic adjustment program executed by the central control device 50, but if a desired target value cannot be obtained, manual adjustment may be required. In that case, additional time is required to obtain an optimal data set. Since the ion implantation process cannot be executed during the execution of the first adjustment method, the productivity of the ion implantation device 100 decreases if the adjustment takes a long time.

[0076] FIG. 10 is a flow chart showing the flow of the second adjustment method, and shows a method of generating a second data set based on an existing first data set. First, a first data set that realizes beam conditions close to desired beam conditions is acquired (S30). The acquired first data set is, for example, an existing data set generated by the first adjustment method of FIG. 9, and is a data set with an implantation record. Note that the first data set may be an existing data set generated by the second preparation method of FIG. 10. In the second preparation method, a new second data set is determined quickly and labor-savingly by calculation based on the existing first data set.

[0077] Next, the difference in voltage amplitude V0 to be introduced to the RF acceleration units 101 to 115 of each stage is calculated (S32). In S32, based on the difference between the target beam energy and the beam energy of the ion beam obtained by the first data set, it is determined which RF acceleration unit of the stage to introduce the difference in voltage amplitude V0, and the change amount or change rate of the voltage amplitude V0 to be introduced to the RF acceleration unit of the determined stage is determined. In this embodiment, the difference in voltage amplitude V0 is introduced to at least one stage of the multiple RF acceleration units 101 to 115. Note that the difference in voltage amplitude V0 may be introduced to two or more stages of the multiple RF acceleration units 101 to 115, or the difference in voltage amplitude V0 may be introduced to more than half of the stages (e.g., eight or more), or the difference in voltage amplitude V0 may be introduced to all of the multiple RF acceleration units 101 to 115. In the RF acceleration units of the stages to which the difference in voltage amplitude V0 is not introduced, the voltage amplitude V0 is the same between the first data set and the second data set.

[0078] In S32, the RF accelerator in the top stage (for example, only the first stage, or the first and second stages) may be excluded from the target for introducing the difference in voltage amplitude V0. In other words, for the RF accelerator in the top stage, the RF parameters included in the first data set may be used as is in the second data set. The RF accelerator in the top stage is used for bunching to consolidate the continuous beam (DC beam) extracted from the ion source 10 into a specific acceleration phase. The bunching by the RF accelerator in the top stage affects the beam capture efficiency in the RF accelerator on the downstream side, and has a significant effect on the overall transport state and beam quality of the beam acceleration unit 14. Therefore, if the RF parameters of the RF accelerator in the top stage are changed, time-consuming adjustment similar to the first adjustment method will be required.

[0079] In S32, the RF accelerator at the lowest stage (e.g., the 15th stage) may also be excluded from the target for introducing a difference in voltage amplitude V0. The RF accelerator at the lowest stage may be provided with a margin for separately introducing a difference in voltage amplitude V0 so that it can be used for final fine adjustment of beam energy, for example. In the beam acceleration unit 14, when the voltage amplitude V0 of an RF accelerator at an intermediate stage is changed, the RF parameters of the RF accelerators at the subsequent stages must be readjusted. On the other hand, in the case of the RF accelerator at the lowest stage, since there are no RF accelerators at or after it, it is possible to save the effort of readjusting the RF parameters of RF accelerators other than the lowest stage.

[0080] In S32, in principle, it is preferable that the number of stages of the radio frequency acceleration unit into which the difference in the voltage amplitude V0 is introduced is as large as possible. By increasing the number of stages of the radio frequency acceleration unit into which the difference in the voltage amplitude V0 is introduced, the amount of change or the rate of change in the voltage amplitude V0 of each stage can be reduced. In addition, it is preferable that the amount of change or the rate of change in the voltage amplitude V0 of each stage is equalized. By making the amount of change or the rate of change in the voltage amplitude V0 of each stage the same, the amount of change or the rate of change in the voltage amplitude V0 of each stage can be reduced. By making the amount of change or the rate of change in the voltage amplitude V0 of each stage as small as possible, the change in the beam transport state in the beam acceleration unit 14 can be reduced, and the change in the beam quality of the ion beam IB output from the beam acceleration unit 14 can be reduced.

[0081] In S32, the change amount or rate of change of the voltage amplitude V0 of each stage may be made intentionally uneven instead of being the same. Also, when there is a circumstance that makes it impossible to introduce the desired difference in the voltage amplitude V0, the RF acceleration unit of some stages in which such a circumstance exists may be excluded. For example, when the difference in the voltage amplitude is introduced, the maximum value of the settable voltage amplitude V0 may be exceeded, or the minimum value of the settable voltage amplitude V0 may be exceeded. In addition, when the difference in the voltage amplitude V0 is smaller than the minimum change amount of the voltage amplitude V0 that can be set in the RF acceleration unit of each stage, the introduction of such a difference is impossible. In such a case, some stages may be excluded and the number of stages of the RF acceleration unit into which the difference in the voltage amplitude V0 is introduced may be reduced so that the difference in the voltage amplitude V0 to be introduced is equal to or larger than the minimum change amount.

[0082] As an example, among the 15-stage RF acceleration units 101-115, the second to fourteenth RF acceleration units 102-114 excluding the top and bottom stages are candidates for introducing a difference in voltage amplitude V0. The change amount or rate of change of the voltage amplitude V0 of each stage is calculated based on the value of the beam energy of the ion beam obtained by the acquired first data set (also called the first output value E1) and the target beam energy value (also called the second output value E2). For example, when the first output value E1=4 MeV and the second output value E2=4.2 MeV, the energy change amount from the first output value E1 to the second output value E2 is 0.2 MeV, and the energy change rate is 5%. When the change amount of the acceleration / deceleration energy ΔE in the RF acceleration units of each stage is made the same, the change amount of the acceleration / deceleration energy ΔE in the RF acceleration units of each stage is about 15.4 KeV. Furthermore, if the rate of change in acceleration / deceleration energy ΔE in the high frequency acceleration section of each stage is made the same, the rate of change in acceleration / deceleration energy ΔE in the high frequency acceleration section of each stage will be 5%. Using the above formula (1), it is possible to calculate the amount of change or rate of change in voltage amplitude V0 of each stage to realize the amount of change or rate of change in acceleration / deceleration energy ΔE in the high frequency acceleration section of each stage. If there is a stage to which the calculated amount of change or rate of change in voltage amplitude V0 of each stage cannot be introduced, for example, that stage is excluded and recalculated. In this way, the difference in voltage amplitude V0 of the high frequency acceleration section of each stage can be determined.

[0083] Next, the difference in the phase φ introduced to the RF acceleration units 101 to 115 of each stage is calculated (S34). In S34, the difference in the phase φ introduced to each stage is calculated so that all the acceleration phases φ0 of the RF acceleration units 101 to 115 of the multiple stages are the same between the first data set and the second data set. The acceleration phase φ0 is calculated based on the RF voltage V RF When the acceleration / deceleration energy ΔE in at least one stage of the multi-stage RF acceleration units 101 to 129 is changed, the velocity v of the ion particle group 90 changes, and the timing at which the center of the ion particle group 90 passes through the center 84 of the RF electrode 72 of each stage changes. Therefore, in order to make the relative acceleration phase φ0 the same, the RF voltage V RF It is necessary to shift the absolute phase φ of the

[0084] In S34, the transport state of the ion particle by the beam acceleration unit 14 operating according to the first data set and the second data set is calculated. Here, the ion particle to be calculated is a representative ion particle such as a first ion particle 91 located at the center of an ion particle group 90 bunched by the uppermost RF accelerator. As the transport state of the ion particle, the time of passing through the RF accelerator of each stage (for example, the center 84 of the RF electrode 72) and the passing energy of the ion particle when passing through the RF accelerator of each stage are calculated. First, based on the first data set, the first time of passing through the RF accelerator of each stage when the first output value E1 is obtained and the first passing energy of the ion particle passing through the RF accelerator of each stage are calculated. Note that the transport state of the ion particle based on the first data set is not calculated each time, and a past calculation result may be used. Next, based on the amount of change or rate of change in acceleration / deceleration energy ΔE in the RF acceleration section of each stage calculated in S32, a second time at which an ion particle passes through the RF acceleration section of each stage when a second output value E2 is obtained and a second passing energy of the ion particle passing through the RF acceleration section of each stage are calculated. Next, a phase difference Δφ=ω·Δt to be introduced into the RF acceleration section of each stage is calculated from the time difference Δt between the first and second times at which an ion particle passes through the RF acceleration section of each stage and the angular frequency ω (=2πf) of the RF acceleration section of each stage. By introducing a phase difference Δφ into the absolute phase φ1 of the RF acceleration section of each stage defined in the first data set, an absolute phase φ2=φ1+Δφ of the RF acceleration section of each stage defined in the second data set is calculated.

[0085] Next, the voltages applied to the lens electrodes of the electrostatic quadrupole lens devices 120a, 120b, 120c, 121-135 of each stage are calculated (S36). In S36, the voltages applied to the lens electrodes of each stage are calculated so that the convergence / divergence effect given to the ion beam IB by the electrostatic quadrupole lens devices 120a, 120b, 120c, 121-135 of each stage is the same between the first data set and the second data set. To make the convergence / divergence effect of the electrostatic quadrupole lens devices the same, it is necessary to change the applied voltage in proportion to the change in energy of the ion beam IB incident on the electrostatic quadrupole lens device.

[0086] In S36, similarly to S34, the transport state of the ion particles by the beam acceleration unit 14 operating according to the first data set and the second data set is calculated. First, based on the first data set, the first incident energy of the ion particles incident on the electrostatic quadrupole lens device of each stage when the first output value E1 is obtained is calculated. Note that the transport state of the ion particles based on the first data set may not be calculated each time, and the past calculation results may be used. Next, based on the amount of change or the rate of change of the acceleration / deceleration energy ΔE in the RF acceleration unit of each stage calculated in S32, the second incident energy of the ion particles incident on the electrostatic quadrupole lens device of each stage when the second output value E2 is obtained is calculated. Next, based on the ratio between the first incident energy and the second incident energy in the electrostatic quadrupole lens device of each stage, the rate of change of the applied voltage of the electrostatic quadrupole lens device of each stage is calculated. The applied voltage to each stage of the electrostatic quadrupole lens device defined in the second data set is calculated by multiplying the applied voltage to each stage of the electrostatic quadrupole lens device defined in the first data set by the calculated rate of change.

[0087] The calculations of the transport state of ion particles in S34 and S36 may be performed separately or simultaneously.

[0088] Next, the operation parameters of various devices provided downstream of the beam acceleration unit 14 are calculated (S38). Specifically, the operation parameters are calculated for controlling the applied voltage of an electric field application device that applies an electric field to the ion beam IB and the applied magnetic field of a magnetic field application device that applies a magnetic field to the ion beam IB. Examples of the electric field application devices provided downstream of the beam acceleration unit 14 include the transverse converging quadrupole lens 26, the beam shaper 32, the beam scanner 34, the beam collimator 36, and the final energy filter 38. Examples of the magnetic field application devices provided downstream of the beam acceleration unit 14 include the energy analysis electromagnet 24 and the bending electromagnet 30.

[0089] In the electric field application device, the value of the applied voltage is set so that the effect of the electric field on the ion beam IB is the same between the first data set and the second data set. In order to make the effect of the electric field applied by the electric field application device on the ion beam IB the same, it is necessary to change the value of the applied voltage so as to be proportional to the energy of the ion beam IB. Therefore, in the electric field application device, it is sufficient to change the applied voltage so as to be a value obtained by multiplying the ratio E2 / E1 of the first output value E1 and the second output value E2.

[0090] Similarly, in the magnetic field application device, the value of the applied magnetic field is set so that the effect of the magnetic field on the ion beam IB is the same between the first data set and the second data set. In order to make the effect of the magnetic field applied by the magnetic field application device on the ion beam IB the same, it is necessary to change the value of the applied magnetic field so that it is proportional to the square root of the energy of the ion beam IB. Therefore, in the magnetic field application device, it is sufficient to change the value of the applied magnetic field so that it becomes a value obtained by multiplying the square root of the ratio of the first output value E1 and the second output value E2, √(E2 / E1).

[0091] Finally, the set of operation parameters calculated in S32 to S38 is determined as a second data set and stored (S40). After that, the ion beam IB generated according to the determined second data set is irradiated onto the wafer to perform an ion implantation process. In the second adjustment method, the second data set can be determined only by calculation without measuring the beam characteristics of the ion beam IB, so that the data set can be determined more quickly than in the first adjustment method. Examples of beam characteristics of the ion beam IB that can be skipped in measurement in the second adjustment method include beam energy, beam current, beam size, beam parallelism, and beam angle.

[0092] Since the second data set is determined based on the existing first data set, the manufacturing error and installation error of the high-frequency electrode 72, the high-frequency voltage V applied to the high-frequency electrode 72, and the like are not included. RFThe errors in amplitude, frequency, and phase of the ion beam IB have already been taken into account. In addition, the operation parameters of the second data set are calculated so that the beam quality is equivalent to that of the first data set, so that an ion beam IB can be generated with only the beam energy changed without substantially changing the beam quality.

[0093] FIG. 11 is a graph showing an example of an error in the energy of the ion beam IB obtained by the second data set. In the example of FIG. 11, the second data set is generated based on the first data set from which an ion beam IB of 2 MeV is obtained, and the second output value E2 is changed in the range of 1 MeV to 3 MeV. That is, the second output value E2 is changed in the range of ±50% based on the first output value E1=2 MeV of the existing first data set. As shown in the figure, even when the beam energy is changed in the range of ±50%, the beam energy can be adjusted with an accuracy of −1% to +0.5%. Also, if the beam energy is in the range of 1.5 MeV to 3 MeV, the beam energy can be adjusted with an accuracy of within ±0.5%.

[0094] It should be noted that, instead of using the second data set determined only by calculation as it is, at least one of the operation parameters defined in the second data set may be adjusted based on at least one measured value of the beam characteristics. For example, the beam energy of the ion beam IB output from the beam acceleration unit 14 operating according to the second data set may be measured, and the voltage amplitude of at least one of the multiple stages of the RF acceleration section may be adjusted based on the measured value of the beam energy. For example, the voltage amplitude of the lowest RF acceleration section 115 may be changed so that the difference between the measured value of the beam energy and the target value falls within an allowable range. As a result, for example, the beam energy can be adjusted with an accuracy of within ±0.1%.

[0095] FIG. 12 is a graph showing an example of the difference in beam current between the ion beam IB obtained by the first data set and the ion beam IB obtained by the second data set. As in FIG. 11, the second data set is generated based on the first data set from which the ion beam IB of 2 MeV is obtained, and the second output value E2 is changed in the range of 1 MeV to 3 MeV. As shown in the figure, even when changing the range of 1.5 MeV to 2.5 MeV, that is, the beam energy in the range of ±25%, the difference in beam current can be kept within the range of -20% to +5%. Also, when changing the beam energy in the range of ±5%, the difference in beam current can be kept within ±5%. From this, it is possible to change the beam energy in the range of ±5% without additional adjustment while maintaining the same beam transport state.

[0096] A plurality of second data sets may be generated from an existing first data set using the above-mentioned second adjustment method. The plurality of second data sets are generated to obtain a plurality of second output values ​​different from each other. For example, a plurality of second data sets may be generated for obtaining a plurality of ion beams IB having beam energies of 1.9 MeV, 1.95 MeV, 2.05 MeV, and 2.1 MeV from a first data set in which an ion beam IB having a beam energy of 2 MeV is obtained. Each of the plurality of second data sets may be used in an ion implantation process without adjustment based on the measurement value of at least one beam characteristic. Each of the plurality of second data sets may be used in an ion implantation process without measuring at least one beam characteristic. In other words, for each of the plurality of ion beams, multi-stage implantation may be performed by skipping the measurement of at least one beam characteristic.

[0097] The second data sets may be used for multi-stage implantation in which the same wafer is irradiated with a plurality of ion beams having different beam energies. For example, the second data sets may be sequentially switched to sequentially irradiate the same wafer with a plurality of ion beams having different beam energies. The first data set and the second data sets may be sequentially switched to sequentially irradiate the same wafer with a plurality of ion beams having different beam energies. For example, the same wafer may be sequentially irradiated with a plurality of ion beams having beam energies of 1.9 MeV to 2.1 MeV at intervals of 0.05 MeV.

[0098] In order to allow the beam energy to be arbitrarily selected over a wide energy range, a plurality of first data sets for obtaining each of a plurality of ion beams having different beam energies from each other may be prepared in advance. When an ion beam having a beam energy different from a specific beam energy of an ion beam obtained by the plurality of first data sets is required, a second data set may be generated based on one of the plurality of first data sets. For example, by preparing a plurality of first data sets for obtaining each of a plurality of ion beams having beam energies changed by 10%, a second data set for obtaining an ion beam having an arbitrary beam energy by changing the beam energy within a range of ±5% can be generated. Furthermore, by preparing a plurality of first data sets corresponding to a plurality of beam conditions having different combinations of conditions such as ion species, ion valence, and beam current amount, a second data set corresponding to an arbitrary beam condition can be quickly generated.

[0099] The second data set may be used to finely adjust the beam energy of the ion beam irradiated to the wafer for each wafer according to the individual difference of the wafer. For example, based on the multiple first data sets for multi-stage implantation, multiple second data sets may be generated for obtaining multiple ion beams having slightly changed beam energies. As an example, when multiple ion beams having beam energies in the range of 1 MeV to 4 MeV at 0.5 MeV intervals are implanted in the same wafer in multiple stages, multiple first data sets are prepared for obtaining multiple ion beams having beam energies of 1 MeV, 1.5 MeV, 2 MeV, 2.5 MeV, 3.5 MeV, and 4 MeV. The multiple ion beams obtained by the multiple first data sets are sequentially irradiated to the first wafer. In the second wafer different from the first wafer, multiple implantations may be required using multiple ion beams having beam energies slightly changed (for example, by 0.05 MeV) from the beam conditions of the first wafer. In this case, based on the plurality of first data sets, a plurality of second data sets for obtaining a plurality of ion beams having beam energies of 1.05 MeV, 1.55 MeV, 2.05 MeV, 2.55 MeV, 3.05 MeV, 3.55 MeV, and 4.05 MeV can be generated by calculation alone. The plurality of ion beams obtained by the plurality of generated second data sets are sequentially irradiated onto the second wafer. By using the second data set for such multi-stage implantation, the time required for generating the data set can be significantly reduced, and the productivity of the ion implantation apparatus 100 can be increased. In addition, since the beam energy can be finely adjusted in a short time, the beam energy can be finely changed on a lot-by-lot or wafer-by-wafer basis without significantly reducing productivity, and the product yield can be improved.

[0100] According to one example of the present embodiment, by changing the voltage amplitude V0 of the multiple-stage RF acceleration unit collectively, the adjustment range of the beam energy can be made wider than when only the voltage amplitude V0 of one RF acceleration unit is changed. Also, within a predetermined adjustment range, the beam energy alone can be adjusted in a wider range than in the past without substantially changing the beam transport state. As a result, ion implantation processing using ion beams having various beam energies becomes very easy.

[0101] 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. In addition, it is possible to suitably rearrange the combinations and processing order in the embodiments based on the knowledge of a person 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. [Explanation of symbols]

[0102] 12...beam generation unit, 14...beam acceleration unit, 16...beam deflection unit, 18...beam transport unit, 20...substrate transport processing unit, 22a, 22b, 22c...linear accelerator, 23...beam measurement unit, 24...energy analysis electromagnet, 26...lateral focusing quadrupole lens, 30...deflection electromagnet, 32...beam shaper, 34...beam scanner, 36...beam collimator, 38...final energy filter, 41...beam monitor, 42...beam profiler, 52a, 52b...electrostatic quadrupole lens device, 70...radio frequency acceleration unit, 72...radio frequency electrode, 74...radio frequency resonator, 78...radio frequency power supply, 100...ion implantation device.

Claims

1. a high-energy multi-stage linear acceleration unit including a plurality of linear accelerators, each of the plurality of linear accelerators having a plurality of stages of high-frequency acceleration sections; a control device for controlling the operation of the high-energy multi-stage linear acceleration unit in accordance with a data set that defines a voltage amplitude, a frequency, and a phase of a radio frequency acceleration section of each stage of each of the plurality of linear accelerators; The control device includes: acquiring a first data set for setting a beam energy of the ion beam output from the high energy multi-stage linear acceleration unit to a first output value; determining a second data set based on the first data set for setting a beam energy of the ion beam output from the high energy multi-stage linear acceleration unit to a second output value different from the first output value; configured to operate the high energy multi-stage linear acceleration unit in accordance with the determined second data set; an acceleration phase of each stage of a high frequency acceleration unit of at least one of the plurality of linear accelerators is the same between the first data set and the second data set in all of the plurality of stages of the high frequency acceleration unit of the at least one linear accelerator; a voltage amplitude of each stage of the radio frequency acceleration unit of the at least one linear accelerator differs between the first data set and the second data set in at least one stage of the radio frequency acceleration unit of the plurality of stages of the at least one linear accelerator; Ion implantation equipment.

2. a voltage amplitude of a radio frequency acceleration section of each stage of the at least one linear accelerator differs between the first data set and the second data set in at least a radio frequency acceleration section other than an uppermost stage and a lowermost stage of the plurality of stages of the at least one linear accelerator; 2. The ion implanter of claim 1.

3. A voltage amplitude of each stage of the radio frequency acceleration unit of the at least one linear accelerator is different between the first data set and the second data set in two or more stages of the radio frequency acceleration units of the at least one linear accelerator.

3. The ion implantation apparatus according to claim 1.

4. A voltage amplitude of a radio frequency acceleration unit of each stage of the at least one linear accelerator differs between the first data set and the second data set in the radio frequency acceleration units of half or more of the stages of the at least one linear accelerator.

4. The ion implanter of claim 3.

5. In the at least one linear accelerator, in the two or more stages of the radio frequency acceleration unit in which the voltage amplitude is different between the first data set and the second data set, a change amount of the voltage amplitude of the radio frequency acceleration unit of each stage is the same between the first data set and the second data set.

5. The ion implantation apparatus according to claim 3.

6. In the at least one linear accelerator, in the two or more stages of the RF acceleration section, in which the voltage amplitude is different between the first data set and the second data set, a change rate of the voltage amplitude of the RF acceleration section of each stage is the same between the first data set and the second data set.

5. The ion implantation apparatus according to claim 3.

7. the control device determines, based on a difference between the first output value and the second output value, to which stage of a radio frequency acceleration section of the at least one linear accelerator is to be introduced the difference in voltage amplitude between the first data set and the second data set.

7. An ion implanter according to any one of claims 1 to 6.

8. the control device determines, based on a difference between a maximum value of a voltage amplitude that can be set in the radio frequency acceleration section of each stage of the at least one linear accelerator and a voltage amplitude of the radio frequency acceleration section of each stage of the at least one linear accelerator defined in the first data set, which stage of the radio frequency acceleration section the at least one linear accelerator should have in the voltage amplitude difference between the first data set and the second data set. An ion implanter according to any one of claims 1 to 7.

9. the control device determines, based on a minimum amount of change in voltage amplitude that can be set in each stage of the radio frequency acceleration unit of the at least one linear accelerator, to which the difference in voltage amplitude is to be introduced between the first data set and the second data set. An ion implanter according to any one of claims 1 to 8.

10. the first data set is determined by adjusting an acceleration phase of at least one of the multiple stages of a radio frequency acceleration section of the at least one linear accelerator based on a measurement value of at least one beam characteristic of an ion beam output from the high energy multi-stage linear acceleration unit; the second data set is determined by adjusting a voltage amplitude of a radio frequency acceleration section of at least one of the stages of the at least one linear accelerator based on a simulation of transport of the ion beam through the high energy multi-stage linear acceleration unit.

10. An ion implanter according to any one of claims 1 to 9.

11. the control device skips measurement of at least one beam characteristic of the ion beam output from the high-energy multi-stage linear acceleration unit operating according to the second data set, and irradiates a wafer with the ion beam output from the high-energy multi-stage linear acceleration unit operating according to the second data set to implant ions. An ion implanter according to any one of claims 1 to 10.

12. The control device includes: measuring at least one beam characteristic of an ion beam output from the high energy multi-stage linear acceleration unit operating in accordance with the second data set; adjusting a voltage amplitude of at least one of the multiple stages of a radio frequency accelerating section of at least one of the multiple linear accelerators defined in the second data set based on the measurement value of the at least one beam characteristic. An ion implanter according to any one of claims 1 to 10.

13. The control device includes: calculating a first time at which an ion particle transported by the high energy multi-stage linear acceleration unit operating according to the first data set passes through each of the stages of RF acceleration and a first pass energy that the ion particle has as it passes through each of the stages of RF acceleration; calculating an acceleration phase of the RF acceleration section of each stage based on the calculated first time and the first passing energy; calculating a second time at which the ion particle passes through the radio frequency acceleration section of each stage and a second passing energy of the ion particle when a voltage amplitude of at least one of the multiple stages of the radio frequency acceleration section included in at least one linear accelerator of the multiple linear accelerators is changed while keeping the calculated acceleration phase fixed; determining a phase of the RF acceleration section of each stage of at least one linear accelerator among the plurality of linear accelerators, which is defined in the second data set, based on a phase of the RF acceleration section of each stage defined in the first data set and a phase difference between the first time and the second time at which the ion particle passes through the RF acceleration section of each stage; 13. An ion implanter according to any one of claims 1 to 12.

14. each of the plurality of linear accelerators includes a plurality of stages of electrostatic quadrupole lens devices, each stage of the electrostatic quadrupole lens devices being disposed downstream of a corresponding stage of the RF accelerator; and the data set further defines an applied voltage for each of the stages of the electrostatic quadrupole lens devices; The control device includes: calculating a first incident energy that an ion particle transported by the high energy multi-stage linear acceleration unit operating according to the first data set has when incident on each of the stages of electrostatic quadrupole lens arrangements; calculating a second incident energy that an ion particle transported by the high energy multi-stage linear acceleration unit operating according to the second data set has when incident on each of the stages of electrostatic quadrupole lens arrangement; determining an application voltage of each stage of an electrostatic quadrupole lens device of at least one linear accelerator among the plurality of linear accelerators defined in the second data set based on an application voltage of each stage of the electrostatic quadrupole lens device defined in the first data set and the first incident energy and the second incident energy of the ion particles when the ion particles are incident on the electrostatic quadrupole lens device of each stage; 14. An ion implanter according to any one of claims 1 to 13.

15. an applied voltage of the electrostatic quadrupole lens device of each stage of at least one of the linear accelerators among the plurality of linear accelerators defined in the second data set is a value obtained by multiplying the applied voltage of the electrostatic quadrupole lens device of each stage defined in the first data set by a ratio of the first incident energy and the second incident energy when the light is incident on the electrostatic quadrupole lens device of each stage; 15. The ion implanter of claim 14.

16. the ion implantation apparatus further comprises an electric field application device disposed downstream of the high energy multi-stage linear acceleration unit and configured to apply an electric field to the ion beam output from the high energy multi-stage linear acceleration unit, the data set further defining an application voltage of the electric field application device; the control device determines an application voltage of the electric field application device defined in the second data set based on the application voltage of the electric field application device defined in the first data set and the first output value and the second output value of the beam energy of the ion beam output from the high-energy multi-stage linear acceleration unit.

16. An ion implanter according to any one of claims 1 to 15.

17. The applied voltage of the electric field application device defined in the second data set is a value obtained by multiplying the applied voltage of the electric field application device defined in the first data set by a ratio between the first output value and the second output value.

17. The ion implanter of claim 16.

18. the ion implantation apparatus further comprises a magnetic field application device disposed downstream of the high energy multi-stage linear acceleration unit and configured to apply a magnetic field to the ion beam output from the high energy multi-stage linear acceleration unit, the data set further defining an applied magnetic field of the magnetic field application device; the control device determines an applied magnetic field of the magnetic field application device defined in the second data set based on the applied magnetic field of the magnetic field application device defined in the first data set and the first output value and the second output value of the beam energy of the ion beam output from the high-energy multi-stage linear acceleration unit.

18. An ion implanter according to any one of claims 1 to 17.

19. The applied magnetic field of the magnetic field application device defined in the second data set is a value obtained by multiplying the applied magnetic field of the magnetic field application device defined in the first data set by the square root of the ratio between the first output value and the second output value.

20. The ion implanter of claim 18.

20. the control device determines a plurality of second data sets based on the first data set for setting beam energy of the ion beam output from the high-energy multi-stage linear acceleration unit to a plurality of second output values ​​different from the first output value; an acceleration phase of each stage of the high frequency acceleration unit of the at least one linear accelerator is the same between the first data set and the plurality of second data sets in all of the plurality of stages of the high frequency acceleration unit of the at least one linear accelerator; a voltage amplitude of each stage of a radio frequency acceleration unit of the at least one linear accelerator differs between the first data set and the plurality of second data sets in at least one stage of a radio frequency acceleration unit of the plurality of stages of the at least one linear accelerator; by switching the plurality of second data sets, a plurality of ion beams output from the high-energy multi-stage linear acceleration unit operating according to each of the plurality of second data sets are sequentially irradiated onto a wafer to implant ions; 20. An ion implanter according to any one of claims 1 to 19.

21. the control device skips measuring at least one beam characteristic for each of the plurality of ion beams.

21. The ion implanter of claim 20.

22. 1. A method of ion implantation using an ion implanter having a high energy multi-stage linear acceleration unit, the high energy multi-stage linear acceleration unit comprising a plurality of linear accelerators, each of the plurality of linear accelerators having a plurality of radio frequency acceleration stages and configured to operate according to a data set defining a voltage amplitude, frequency and phase of each of the radio frequency acceleration stages; The ion implantation method includes: acquiring a first data set for setting a beam energy of an ion beam output from the high energy multi-stage linear acceleration unit to a first output value; determining a second data set based on the first data set for setting a beam energy of the ion beam output from the high energy multi-stage linear acceleration unit to a second output value different from the first output value; and implanting ions into a wafer by irradiating the wafer with the ion beam output from the high energy multi-stage linear acceleration unit operating according to the second data set; an acceleration phase of each stage of a high frequency acceleration unit of at least one of the plurality of linear accelerators is the same between the first data set and the second data set in all of the plurality of stages of the high frequency acceleration unit of the at least one linear accelerator; A voltage amplitude of each radio frequency acceleration section of the at least one linear accelerator is different between the first data set and the second data set in at least one radio frequency acceleration section of the plurality of stages of the at least one linear accelerator. Ion implantation method.

Images