Hybrid instruments, systems, and techniques for mass spectrometry ion beams

Abstract

An apparatus comprising an electrodynamic mass spectrometry (EDMA) assembly. The EDMA assembly may include a first upper electrode positioned above the beam axis and a first lower electrode positioned below the beam axis opposite the first upper electrode. The EDMA assembly is configured to receive a first RF voltage signal at a first frequency. The apparatus may include a deflection assembly positioned downstream of the EDMA assembly. The deflection assembly comprises a blocker positioned along the beam axis. The apparatus may include an energy spread reducer (ESR) positioned downstream of the deflection assembly. The energy spread reducer is configured to receive a second RF voltage signal at a second frequency, twice the first frequency. The ESR may include an upper ESR electrode positioned above the beam axis and a lower ESR electrode positioned below the beam axis.

Description

[Technical Field]

[0001] Cross-reference of related applications

[0001] This application claims priority to U.S. Patent Application No. 18 / 131,287, filed on 5 April 2023. The contents of said U.S. Patent Application are incorporated herein by reference in their entirety.

[0002]

[0002] This disclosure relates more broadly to ion beam apparatus, and more particularly to ion implantation apparatus having mass spectrometry capabilities. [Background technology]

[0003]

[0003] Ion implantation is the process of introducing dopants or impurities into a substrate via collision. An ion implantation system ("ion implantation apparatus") may comprise an ion source and a substrate stage or process chamber that houses the substrate to be implanted. The ion source may comprise a chamber from which ions are generated. A beamline ion implantation apparatus may comprise a series of beamline components, such as a mass spectrometer, a collimator, and various components for accelerating or decelerating the ion beam.

[0004]

[0004] A useful function of an ion implanter beamline is to separate ions of different masses. This allows for the formation of an ion beam containing the desired ions for processing a workpiece or substrate, while unwanted ions are blocked within the beamline components and do not reach the substrate. In known systems, this mass spectrometry function is provided by an analytical magnet. This analytical magnet bends the beam of ions, all of the same energy, in a curve whose radius depends on the mass, thereby achieving the required separation. However, this type of magnet is large, expensive, and heavy, and accounts for a significant portion of the cost and power consumption of the ion implanter.

[0005]

[0005] Compact ion beam systems have been developed for relatively low-energy ion implantation, such as energies below approximately 50 keV. These ion beam systems may include a plasma chamber that acts as an ion source and may be located adjacent to a process chamber that houses the substrate to be implanted. The ion beam may be extracted from the plasma chamber using an extraction grid or other extraction optics to provide the substrate with an ion beam having a desired beam shape, such as a ribbon beam. In these latter systems, mass spectrometry may be omitted because of the size / space required to install the aforementioned magnet analyzer, as well as the cost. Therefore, the use of such compact ion beam systems may be limited to applications where the purity of the implanted species is not strictly required.

[0006]

[0006] Recently, an approach has been proposed for ion beam processing systems. This approach uses electrodynamic mass spectrometry (EDMA) components to generate a mass-analyzed ion beam within a more compact ion beam processing apparatus. This approach applies a high-frequency electric field to remove ions of undesirable mass. However, EDMA designs devised to date may not be able to generate an acceptable flux for ions of the target mass, especially when operating at high beam currents overall. In addition, such EDMA designs may generate ion energies with an unacceptable spread for the mass-analyzed ion beam.

[0007]

[0007] This disclosure is presented in connection with the above considerations and other considerations. [Overview of the Initiative]

[0008]

[0008] In one embodiment, an apparatus is provided that includes an electrodynamic mass spectrometry (EDMA) assembly. The EDMA assembly may include a first upper electrode positioned above the beam axis and a first lower electrode positioned below the beam axis opposite the first upper electrode. The EDMA assembly is configured to receive a first RF voltage signal at a first frequency. The apparatus may include a deflection assembly positioned downstream of the EDMA assembly. The deflection assembly comprises a blocker positioned along the beam axis. The apparatus may include an energy spread reducer (ESR) positioned downstream of the deflection assembly. The energy spread reducer is configured to receive a second RF voltage signal at a second frequency twice the first frequency. The ESR may include an upper ESR electrode positioned above the beam axis and a lower ESR electrode positioned below the beam axis.

[0009]

[0009] In another embodiment, the ion beam processing system may include an ion source for generating an ion beam as a continuous ion beam and an electrodynamic mass spectrometry (EDMA) assembly located downstream of the ion source. The EDMA assembly may include a first upper electrode located above the beam axis and a first lower electrode located below the beam axis opposite the first upper electrode. The EDMA assembly is configured to receive a first RF voltage signal at a first frequency. The ion beam processing system may include a deflection assembly located downstream of the EDMA assembly, the deflection assembly comprising a blocker, and an energy spread reducer (ESR) located downstream of the deflection assembly. The ESR may be configured to receive a second RF voltage signal at a second frequency twice the first frequency. The energy spread reducer includes an upper ESR electrode located above the beam axis and a lower ESR electrode located below the beam axis.

[0010]

[0010] In another embodiment, the method may include directing an ion beam as a continuous ion beam into an EDMA assembly. The EDMA assembly includes a first upper electrode and a first lower electrode. The method may include applying a first RF voltage signal at a first frequency to the ion beam within the EDMA assembly while the ion beam is being transported through the EDMA assembly. The method further includes using a blocker to block the path of a portion of the ion beam along the beam axis at a location downstream of the EDMA assembly. Thereby, a mass analyzed bunched ion beam is generated. The method also includes applying an acceleration RF voltage signal to the mass analyzed bunched ion beam when the bunched ion beam passes through an energy spread reducer. The acceleration RF voltage signal is applied at a second frequency that is twice the first frequency.

Brief Description of the Drawings

[0011] [Figure 1A]

[0011] An exemplary system according to embodiments of the present disclosure is shown. [Figure 1B]

[0012] Another exemplary system according to embodiments of the present disclosure is shown. [Figure 1C]

[0013] A further exemplary system according to embodiments of the present disclosure is shown. [Figure 1D]

[0014] An additional exemplary system according to embodiments of the present disclosure is shown. [Figure 2A]

[0015] Transport of a target ion species according to one scenario for operating the apparatus of FIG. 1D according to other embodiments of the present disclosure is shown. [Figure 2B]

[0016] An exemplary energy profile of an ion beam processed within the apparatus of FIG. 2A is shown. [Figure 2C]

[0017] Figure 2C shows an example energy profile of an ion beam processed in a device without ESR. [Figure 3A]

[0018] This invention illustrates the operation of the device under one scenario according to one embodiment of the present disclosure. [Figure 3B] This invention illustrates the operation of the device under one scenario according to one embodiment of the present disclosure. [Figure 3C] This invention illustrates the operation of the device under one scenario according to one embodiment of the present disclosure. [Figure 4]

[0019] This disclosure illustrates one embodiment of the operation of another device under a different scenario, based on multiple embodiments of this disclosure. [Figure 5A]

[0020] This describes the adjustment of the energy profile of an ion beam using voltage control of the RF voltage in an ESR within a device arranged according to several embodiments of this disclosure. [Figure 5B] This describes the adjustment of the energy profile of an ion beam using voltage control of the RF voltage in an ESR within a device arranged according to several embodiments of this disclosure. [Figure 5C] This describes the adjustment of the energy profile of an ion beam using voltage control of the RF voltage in an ESR within a device arranged according to several embodiments of this disclosure. [Figure 5D] This describes the adjustment of the energy profile of an ion beam using voltage control of the RF voltage in an ESR within a device arranged according to several embodiments of this disclosure. [Figure 6A]

[0021] This describes the adjustment of the energy profile of an ion beam using phase control of the RF voltage in the ESR within a device arranged according to several embodiments of this disclosure. [Figure 6B] This describes the adjustment of the energy profile of an ion beam using phase control of the RF voltage in the ESR within a device arranged according to several embodiments of this disclosure. [Figure 6C]This describes the adjustment of the energy profile of an ion beam using phase control of the RF voltage in the ESR within a device arranged according to several embodiments of this disclosure. [Figure 6D] This describes the adjustment of the energy profile of an ion beam using phase control of the RF voltage in the ESR within a device arranged according to several embodiments of this disclosure. [Figure 7A]

[0022] This shows one specific embodiment of a focused ion beam assembly. [Figure 7B]

[0023] Another embodiment of a focused ion beam assembly is shown. [Figure 8]

[0024] The following are exemplary process flows according to several embodiments of the present disclosure. [Modes for carrying out the invention]

[0012]

[0025] The drawings are not necessarily to scale. The drawings are for illustrative purposes only and are not intended to represent any particular parameter of the disclosure. The drawings are intended to illustrate exemplary embodiments of the disclosure and should therefore not be considered limiting. In the drawings, similar numbering represents similar elements.

[0013]

[0026] The apparatus, systems, and methods relating to this disclosure will be fully described below with reference to the accompanying drawings illustrating embodiments of the systems and methods. The systems and methods may be implemented in many different forms and should not be construed as being limited to the embodiments specified herein. Rather, these embodiments are provided to make this disclosure detailed and complete and to fully convey the scope of the systems and methods to those skilled in the art.

[0014]

[0027] Here, any element or operation following the singular form of “one” or “a” (a, an) is understood to potentially include multiple elements or operations. Furthermore, any reference to “one embodiment” in this disclosure is not intended to be construed as excluding the existence of additional embodiments that also incorporate the enumerated features.

[0015]

[0028] An approach for a mass spectrometry ion implantation system using a novel mass spectrometry device is provided herein. In various embodiments, the mass spectrometry device may be implemented within a beamline ion implanter or within a compact ion beam system.

[0016]

[0029] Figure 1A shows an ion beam processing system 100 according to various embodiments of the present disclosure. The ion beam processing system 100 includes an ion source 12 for generating an ion beam 14 as a continuous ion beam, an EDMA assembly 20 arranged to receive the ion beam 14 and generate a mass spectrometry ion beam, and an electrostatic energy filter, shown as an energy filter 60, arranged to generate an energy-filtered mass spectrometry ion beam that is guided to a substrate 70, shown as ion beam 14AM. Since the structure and operation of electrostatic energy filters are well known, details of the electrostatic energy filter 60 will be omitted herein. The basic operation of such an energy filter employs a set of electrodes 62 arranged around the ion beam path. These electrodes 62 deflect the ion beam and apply a series of target DC (static) voltages to accelerate and / or decelerate the ion beam. In doing so, the electric field generated within the electrostatic energy filter 60 removes unwanted ion species and high-energy neutral species with energies different from the target energy or target range of energy. The general function of the EDMA assembly 20 is to remove ions of unwanted mass and deliver ions of the target mass into the energy filter 60.

[0017]

[0030] According to various embodiments of this disclosure, the EDMA assembly 20 can receive the ion beam 14 as a continuous ion beam. In some embodiments, the ion beam processing system 100 also includes a focused ion beam assembly 102. The operation of the focused ion beam assembly is described in detail below. When received, the ion beam 14 may have a trajectory along the beam axis, i.e., along the Z-axis in the illustrated Cartesian coordinate system. In the embodiment of Figure 1A, the beam axis may lie between the first upper electrode 22 and the first lower electrode 24, and in some embodiments, it may lie in the middle of the EDMA assembly, such as midway between the first upper electrode 22 and the first lower electrode 24, as indicated by the dashed line. The EDMA assembly 20 may include an EDMA power supply 32 for applying a first RF signal between the first upper electrode 22 and the first lower electrode 24. In particular, the RF signal between the first upper electrode 22 and the first lower electrode 24 may be supplied such that the phase of the RF signal at the upper electrode is shifted by 180 degrees relative to the phase of the RF signal at the first lower electrode 24.

[0018]

[0031] In various non-limiting embodiments, the suitable frequency for the RF signal of this disclosure may be in the range of 200 kHz to 100 MHz. As detailed in the following discussion, the first RF signal deflects the ion beam 14 in a manner that assists mass filtering.

[0019]

[0032] The EDMA assembly 20 may further include a deflection assembly 50 located downstream of the EDMA assembly 20. The deflection assembly 50 includes a blocker 56 positioned along the beam axis. In some embodiments, the deflection assembly 50 may include an upper deflection electrode 52 located on a first side of the blocker 56, a lower deflection electrode 54 located on a second side of the blocker 56, and a deflection power supply 34 positioned to apply a static bias voltage between one blocker 56 and the other upper deflection electrode 52 and lower deflection electrode 54. Note that for illustrative clarity, certain walls forming part of the EDMA assembly 20 or a similar EDMA apparatus are omitted in Figure 1A and several other drawings.

[0020]

[0033] As further shown in Figure 1A, the ion beam processing system 100 may also include an energy spread reducer 40 located downstream of the deflection assembly 50. The energy spread reducer (ESR) 40 may include an ESR power supply 36 arranged to supply a second RF voltage signal to the electrodes of the ESR 40 at a second frequency twice the first frequency of the EDMA assembly 20. In the embodiment of Figure 1A, the ESR 40 includes an upper ESR electrode 42A located above the beam axis and a lower ESR electrode 42B located below the beam axis. These electrodes simultaneously receive the second RF signal at the same amplitude and phase.

[0021]

[0034] In some embodiments, the electrodes of the EDMA assembly 20 and ESR 40 are elongated along the electrode axis (represented by the X-axis), and the electrode axis extends perpendicular to the beam axis. This configuration may be particularly suitable for processing ribbon beams, which are characterized by a long axis in the cross-section extending along the X-axis. However, in several other embodiments, the EDMA assembly 20 and ESR 40 may be shaped to process spot beams or pencil beams having a more equiaxial shape in the cross-section.

[0022]

[0035] As shown in Figure 1A, during operation, the EDMA assembly 20 can perform a mass filtering operation on the ion beam 14 by deflecting the constituent ions of the ion beam 14 along different trajectories so as to block ions whose mass does not correspond to the target ion mass, while delivering ions of the target mass through the energy filter 60. The ions in the ion beam portion 14A then pass through the electrostatic energy filter 60 before colliding with the substrate 70. In one embodiment, the ion beam 14 is B + This can represent a boron ion beam containing the majority of ions. Ion beam 14 is F + BF + BF2 + It may contain other constituent ions that are generally considered to be impurity ions.

[0023]

[0036] In particular, an RF field is generated between the first upper electrode 22 and the first lower electrode 24, and the frequency of the RF signal generating the RF field can be selected according to the energy of the ions in the ion beam 14, as well as the mass of the constituent ions. By selecting an appropriate frequency and maximum amplitude of the RF voltage, the ions to be removed can be deflected to trajectories that are blocked by the surfaces of the various components in the EDMA assembly 20. For clarity of explanation, in the example in Figure 1A, B + Ion beam section 14A representing ions, and F + Only the ion beam portion 14B representing ions is shown. However, depending on the type of ion source and the type of ion species supplied to the ion source 12, other ion species may be present in the boron ion beam entering the EDMA assembly 20. As shown in the figure, these portions are B + and F + The ions can propagate through the EDMA assembly while having different spatial distributions resulting from their different masses. By selecting the appropriate frequency and amplitude of the RF signal applied to the EDMA assembly 20, the ion beam portion 14A can be deflected in such a way that a relatively large portion of the ion beam portion 14A tends to be guided to pass through the EDMA assembly 20 to the substrate 70, compared to the ion beam portion 14B.

[0024]

[0037] In particular, a DC voltage may be applied between the blocker 56 and the upper and lower deflection electrodes 52 and 54, where components can be grounded, as ions pass through the region between the blocker 56 and the upper or lower deflection electrode 52 or 54. This DC voltage may be set to reduce or eliminate the average vertical velocity of ion bunches, such as bunch 14A-1, as the bunch leaves the EDMA assembly, by removing unwanted mass ions and providing the necessary deflection for desired ion species.

[0025]

[0038] As further shown in FIG. 1A, by using the blocker 56 to block the path of a portion of the ion beam 14 that lies near or along the beam axis at a location downstream of the EDMA electrodes, in addition to mass filtering, bunching of the ions within the ion beam 14 occurs, whereby the ion beam 14 exits the EDMA assembly 20 as an ion beam that has been mass analyzed into a beam. As an example, the bunch 14A-1 can represent B ions having a target mass for ion implantation. + ions. The bunch 14B-1 can represent F + ions. As shown in FIG. 1A, the F + ions represented by the ion beam portion 14B can constitute a relatively large portion of the ion beam 14 when entering the EDMA assembly, but the bunch 14B-1 constitutes a relatively small portion of the ions exiting the EDMA assembly compared to the bunch 14A-1 representing B+ ions.

[0026]

[0039] During operation, when the ion beam 14 traverses the EDMA assembly 20, a spread in a particular energy or energy dispersion is imparted to the ion beam 14. This spread in energy can occur along the direction of beam propagation, such as generally along the Z-axis, as well as along the energy spread along the Y-axis. For example, a B + ion beam having a nominal energy of 20 keV can exhibit an energy spread of 3 keV to 6 keV after exiting the EDMA assembly 20 according to some non-limiting embodiments.

[0027]

[0040] According to several embodiments of this disclosure, the ESR40 reduces the energy spread of ions in the ion beam 14 by applying an RF field at the electrodes of the ESR40 to selectively accelerate and decelerate ions in a given ion bunch, such as bunch 14A-1. In particular, when ions from bunch 14A-1 enter the ESR40, an RF voltage signal may be applied at twice the frequency of the RF voltage signal used in the EDMA20. As previously stated, the ions in bunch 14A-1 may have an ion energy range such as between 17keV and 23keV relative to a nominal ion energy of 20keV. The distribution of ions in bunch 14A-1 may correlate with the ion energy of these ions. Thereafter, slower ions tend to be located upstream (left in the diagram), while faster (higher energy) ions tend to be located downstream (right). As the RF voltage signal is applied between the upper ESR electrode 42A and the lower ESR electrode 42B, an oscillating electric field (not shown) at the RF frequency is generated in the space traversed by bunch 14A-1. This electric field tends to accelerate and decelerate bunch 14A-1 as it traverses ESR 40. Since slower ions enter ESR 40 in different instances than faster ions, the magnitude of the acceleration / deceleration electric field in ESR 40 experienced by leading ions (faster ions) is generally different from the magnitude of the acceleration / deceleration electric field experienced by lagging ions (slower ions). With appropriate timing that takes into account not only the phase of the RF signal applied to the EDMA assembly 20 but also the energy of the ions in incoming bunches such as bunch 14A-1, the RF voltage signal can be supplied to ESR 40 in a manner that tends to slow down leading ions (faster ions) and accelerate lagging ions (slower ions). As a result, the energy spread within the bunches in the ion beam 14 can be reduced by ESR 40.

[0028]

[0041] The ion beam processing system 100 provides a compact approach for generating a mass spectrometry ion beam with acceptable energy dispersion, and the yield of ions of the target mass output to the substrate 70 may be relatively low for a given application. In order for the ESR 40 to operate properly, bunches such as bunch 14A-1 in the ion beam 14 are necessary. + The length of a bunch should ideally be equal to the following quantity: (B + This is 1 / 4 of the ion velocity × 1 RF period of the EDMA assembly 20. Such requirements are "ideal" B + The transmittance can be limited to 50%. That is, the magnitude of the beam current output by the ESR40 can be equal to 50% of the magnitude of the current input into the EDMA assembly 20.

[0029]

[0042] Returning to the focused ion beam assembly 102, this component can help control the space charge effect that tends to cause beam blow-up, especially when the current density for the ion beam 14 is relatively high. The inventors believe that BF + and BF2 + B, a relatively high current containing the species + In computer simulations of ion beams, BF + and BF2 + We found that a relatively significant beam potential can develop at the center of the EDMA assembly 20 due to space charge effects from heavier species such as ions. This potential is B + There is a tendency to drive ions containing ions into uncompensated orbitals. As a result, B + Instead of navigating around the blocker 56 and exiting the EDMA assembly 20, the ions may be driven to the inner walls or other surfaces of the EDMA assembly 20. By guiding the ion beam 14 as a focused ion beam, the space charge effect that tends to blow up the ion beam 14 can be compensated, B + This allows a larger portion of the target mass ions to propagate through the EDMA assembly 20, which leads to a higher yield.

[0030]

[0043] Figure 7A shows one specific embodiment of a focused ion beam assembly 300 formed from a tetrode assembly. The tetrode assembly may include a first electrode 302, such as a plate of an ion source. The plate is biased at the final beam energy. A suppression electrode 304 is negatively biased relative to the first electrode 302 to extract the ion beam. A "defocus" electrode 306 is positively biased relative to the suppression electrode 304 to slow the ion beam and increase the beam vertical size, and a "ground" electrode 308 is provided at the beamline potential to generate a focused ion beam 310 entering the EDMA assembly 20.

[0031]

[0044] It should be noted that this configuration differs from known tetrode extraction assemblies in which a defocus electrode similar to the defocus electrode 306 is maintained negatively relative to the beamline to maintain beamline neutralization. However, such neutralization is not necessary for the operation of the EDMA assembly 20.

[0032]

[0045] In another embodiment shown in Figure 7B, the focused ion beam assembly 350 may be configured as an Einzel lens having three sets of electrodes as shown. In this case, the central electrode is biased relative to the first and last electrodes to generate the focused ion beam 360.

[0033]

[0046] Figure 1B shows an ion beam processing system 100B arranged according to a further embodiment of the present disclosure. Ion beam processing system 100B can be considered a variation of ion beam processing system 100. In this case, similar elements are given the same labels. Ion beam processing system 100B differs from ion beam processing system 100 in the configuration of the ESR. In this embodiment, the ESR 40B includes a set of DC electrodes coupled to set the beamline potential. These DC electrodes may include a first set (electrodes 44A, 44B) positioned upstream of the upper ESR electrode 42A and the lower ESR electrode 42B, as shown. These DC electrodes may also include a second set (electrodes 46A, 46B) positioned downstream of the upper ESR electrode 42A and the lower ESR electrode 42B. The advantages of the ESR 40B are as follows: In other words, DC electrodes are provided within the ESR40B that tend to generate an electric field in the beam propagation direction, and this electric field extends more closely parallel to the Z-axis, providing a more uniform electric field distribution in the direction perpendicular to the propagation direction of ion bunches along the Z-axis. This more uniform Z-axis field in the Y-direction tends to more effectively reduce the energy spread of ion bunches across the ESR40B (see Figure 2A below).

[0034]

[0047] Figure 1C shows an ion beam processing system 100C arranged according to a further embodiment of the present disclosure. Ion beam processing system 100C can be considered a variation of ion beam processing system 100. In this case, similar elements are given the same labels. Ion beam processing system 100C differs from ion beam processing system 100 in the configuration of the ESR. In this embodiment, ESR 40C includes an intermediate ESR electrode 42C positioned between the upper ESR electrode 42A and the lower ESR electrode 42B. The upper ESR electrode 42A, the intermediate ESR electrode 42C, and the lower ESR electrode 42B form a dual-channel ESR. The advantages of ESR 40C are as follows: the intermediate ESR electrode 42C tends to generate an electric field which extends more closely parallel to the Z-axis and provides a more uniform electric field in a direction perpendicular to the direction of propagation of the ion bunch along the Z-axis. This more uniform Z-axis field in the Y direction tends to more effectively reduce the energy spread of ion bunches across ESR40C (see Figure 2A below).

[0035]

[0048] Figure 1D shows an ion beam processing system 100D arranged according to a further embodiment of the present disclosure. Ion beam processing system 100D can be considered a variation of ion beam processing system 100. In this case, similar elements are given the same labels. Ion beam processing system 100D differs from ion beam processing system 100 in the configuration of the ESR. In this embodiment, ESR 40D includes an intermediate ESR electrode 42C positioned between the upper ESR electrode 42A and the lower ESR electrode 42B. The upper ESR electrode 42A, the intermediate ESR electrode 42C, and the lower ESR electrode 42B form a dual-channel ESR. ESR 40D may further include optional DC electrodes coupled to be set to beamline potential. These DC electrodes may include a first set (electrodes 44A, 44B, and 44C) positioned upstream of the upper ESR electrode 42A and the lower ESR electrode 42B, as shown. These DC electrodes may also include a second set (electrodes 46A, 46B, and 46C) positioned downstream of the upper ESR electrode 42A and the lower ESR electrode 42B. The advantages of ESR40D are as follows: an intermediate ESR electrode 42C is provided which tends to generate an electric field that extends more closely parallel to the Z-axis and therefore provides a more uniform electric field in a direction perpendicular to the direction of ion bunch propagation along the Z-axis. This more uniform Z-axis field in the Y-direction tends to more effectively reduce the energy spread of ion bunches across ESR40D. In addition, the DC electrodes (44A-44C and 46A-46C) further provide a region that tends to generate an electric field along the Y-axis (see Figure 2A below).

[0036]

[0049] Referring back to Figure 2A, a computer simulation of the electric field and ion beam position within the ion beam processing system 100D under one operating scenario is shown. In this embodiment, an 18 mA boron beam is input with an energy of 21 keV, and a maximum amplitude voltage signal of 3 kV is applied to the first upper electrode 22 and the first lower electrode 24 of the EDMA assembly 20 at a first frequency. Referring also to Figure 1B, a DC deflection voltage of 1500 V is applied between one blocker 56 and the other upper deflection electrode 52 and lower deflection electrode 54. A double frequency RF voltage signal with a maximum amplitude of 500 V is applied to the ESR 40A at twice the frequency of the first RF signal applied to the first upper electrode 22 and the first lower electrode 24. In addition, the double frequency RF voltage signal in the ESR 40A is shifted by 300 degrees in phase with respect to the first RF voltage signal in the EDMA assembly 20.

[0037]

[0050] As shown in Figure 2A, an electric field 120 develops between the first upper electrode 22 and the first lower electrode 24. This electric field is represented by a horizontal potential line. The electric field 120 oscillates at the RF frequency of the applied voltage signal, while generally imparting a velocity component to the ion beam 110, so that the ion beam 110 may exhibit wave-like characteristics. When the ion beam 110 interacts with the blocker 56 of the deflection assembly 50 at any given period (360 degrees) of the RF electric field 120, the blocker 56 effectively generates two separate ion bunches that pass through the deflection assembly 50 and the ESR 40D.

[0038]

[0051] The DC electric field 124 generated by the deflection assembly 50 has a somewhat more complex shape and tends to deflect positive ion beams, such as the ion beam 110, inward toward the beam axis 112. The ESR 40D generates an energy spreading reduction (ESR) electric field 130 at twice the frequency of the RF electric field 120, and has an electric field line that is roughly shaped as a vertical field (i.e., along the Y axis) as shown. Since two separate ion bunches pass through the ESR 40D in a single period of the RF electric field 120, the ESR electric field 130 oscillates in a way that treats both ion bunches similarly as the ion bunches pass through the ESR 40D sequentially, by having half the period of the RF electric field 120.

[0039]

[0052] As a result, after the ion beam 110 is deflected, focused, and accelerated through the ion beam processing system 100A, approximately 35% (6mA) of B is applied. + The current yield is achieved in the substrate. In that case, the energy spread will be as shown in Figure 2B. All other species (e.g., BF + BF2 + ) is a small F + Except for that portion, access to the substrate 70 is blocked.

[0040]

[0053] Referring back to Figure 2B, we see the ion energy distribution function corresponding to the conditions outlined for the scenario in Figure 2A. The ion current distribution is characterized by a peak with a full width at half maximum of 50 eV and a total energy spread of 400 eV.

[0041]

[0054] It should be noted that instead of the ESR, a device may be conceivable in which a second “stage” of the EDMA assembly may be located downstream of the deflection assembly 50. This configuration is shown in Figure 2C, which shows the ion beam processing system 200, and similar components are labeled the same as in the several embodiments described above. In this embodiment, the ESR 40 is replaced by a second set of RF electrodes, illustrated as a second upper electrode 242 and a second lower electrode 244. This embodiment functions as a two-stage EDMA assembly, where the first stage 230 may operate similarly to the EDMA assembly 20. The second stage 240 applies an RF electric field similar to that of the first stage 230. In that case, as a result, unwanted mass (e.g., F) is eliminated. + BF + , and BF2 + Effective mass filtering of ) can be achieved. In addition, B + In this case, a current yield of 50% can be achieved. A challenge with the ion beam processing system 200 is that, due to the lack of ESR40 or ESR40A, the energy spread of the analyzed ion beam can become excessively broad. This challenge is highlighted in the graph in Figure 2C. This graph shows the beam energy profile of a nominal 20 keV produced by the ion beam processing system 200, with a total energy spread of 2.5 keV.

[0042]

[0055] Referring back to Figure 3A, another scenario for the operation of the ion beam processing system 100A is shown. In this embodiment, an 18 mA boron beam is input at an energy of 21 keV, and a maximum amplitude voltage signal of 3.5 kV is applied to the first upper electrode 22 and the first lower electrode 24 of the EDMA assembly 20 at a first frequency. Referring also to Figure 1B, a positive voltage of +400 V is applied to the upper deflection electrode 52 and the lower deflection electrode 54, while the blocker 56 is biased at -400 V. A double frequency RF voltage signal with a maximum amplitude of 400 V is applied to the ESR 40A at twice the frequency of the first RF signal applied to the first upper electrode 22 and the first lower electrode 24. In addition, the double frequency RF voltage signal in the ESR 40A is shifted by 300 degrees in phase with respect to the first RF voltage signal in the EDMA assembly 20. Under these conditions, output B + The current is 9 mA, which corresponds to a yield or transmittance of up to 50%. The current in the substrate is shown as a function of time in Figure 3C. This shows a series of regular peaks corresponding to time-separated ion bunches according to the frequency of the RF voltage applied in the ion beam processing system 100A. As shown in Figure 3B, the ion current distribution is characterized by a peak with a full width at half maximum of 40 eV and a total energy spread of 600 eV. Therefore, changing the voltage amplitude at the RF electrode of the EDMA assembly 20, as well as changing the DC voltage in the deflection assembly 50, can improve the transmittance of ions of the target species. As shown in Figure 3A, F + Some of the ions may not be filtered and could collide with the substrate 70.

[0043]

[0056] Referring back to Figure 4, another scenario for the operation of a different ion beam processing system is shown according to several further embodiments of the present disclosure. As shown, the ion beam processing system 100B may include the same components as those previously described with respect to the ion beam processing system 100A. In addition, the ion beam processing system 100B includes a block aperture (shown as aperture component 48) located downstream of the ESR 40A. In this embodiment, an 18 mA boron beam is input at an energy of 21 keV, and a maximum amplitude voltage signal of 3.5 kV is applied to the first upper electrode 22 and the first lower electrode 24 of the EDMA assembly 20 at a first frequency. Referring also to Figure 1B, a positive voltage of +400 V is applied to the upper deflection electrode 52 and the lower deflection electrode 54, while the blocker 56 is biased at -400 V. A double-frequency RF voltage signal with a maximum amplitude of 400V is applied to the ESR40A at twice the frequency of the first RF signal applied to the first upper electrode 22 and the first lower electrode 24. In addition, the double-frequency RF voltage signal in the ESR40A is shifted by 300 degrees relative to the phase of the first RF voltage signal in the EDMA assembly 20. The beam is then decelerated to an energy of 700eV using the EPM60. Under these conditions, output B + The current is 7mA, which corresponds to a yield or transmittance of up to 40%. Therefore, changing the voltage amplitude in the RF electrode of the EDMA assembly 20, and changing the DC voltage in the deflection assembly 50, can improve the transmittance of ions of the target species and remove unwanted species. In this configuration, all F + BF + BF2 + The ions are removed.

[0044]

[0057] As previously stated with respect to Figure 2B, an ESR such as ESR40 or ESR40A may be employed to reduce the energy spread of the ion beam output by the EDMA according to several embodiments. According to several further embodiments of the present disclosure, the operating parameters of the ion beam processing system including the EDMA and ESR may be adjusted to match the ion beam energy profile according to the target application. Figures 5A to 5D present a series of ion energy profiles of boron ion beams produced by modified ion beam processing devices. In this case, the maximum amplitude of the RF voltage applied to the ERS is changed. In each ion beam energy profile, the phase difference between the RF voltage applied to the EDMA assembly and the accelerating RF voltage applied to the ESR is 330 degrees. Figure 5A corresponds to 400V, Figure 5B to 500V, Figure 5C to 600V, and Figure 5D to 700V. The nominal energy of the boron ion beam entering the ESR is 21 keV in all of these embodiments. As shown in Figure 5A, at a setting of 400V, the ESR RF voltage is effective in generating a very narrow energy distribution, as previously described. At 500V, the energy spread becomes considerably wider, resulting in a bimodal distribution with two partially separated peaks of different energies separated by 150eV. At 600V, a clear bimodal energy distribution is illustrated, with two symmetrical peaks separated by approximately 300eV. At 700V, the bimodal distribution is still present, with peak separation up to 500eV.

[0045]

[0058] From the above perspective, the RF voltage amplitude can be adjusted to control the energy distribution in order to provide a range of ion implantation profiles for ion implantation. Several other approaches can use beam energy profile adjustment to mimic the ion distribution used in etching processes.

[0046]

[0059] According to several further embodiments of the present disclosure, the operating parameters in Figures 6A–6D present a series of ion beam energy profiles of a boron ion beam produced by a modified ion beam processing apparatus. In this case, the phase difference of the RF voltage applied to the ESR is changed. In each profile, the RF voltage applied to the ESR is 700V, while the phase difference varies between 300 and 340 degrees. In each of these embodiments, there is a bimodal distribution of ion energy with a peak separation of approximately 500 eV. The difference is that the distribution of beam current as a function of ion energy is systematically shifted from low energy to high energy as the phase shift increases.

[0047]

[0060] Figure 8 shows a process flow 800 according to several embodiments of the present disclosure. In block 802, the ion beam is introduced into an electrodynamic mass spectrometry (EDMA) assembly as a focused ion beam.

[0048]

[0061] In block 804, a first RF signal is applied to the RF electrode of the EDMA assembly at a first RF voltage and a first frequency. The RF electrode of the EDMA assembly may include a first upper electrode and a first lower electrode configured to receive the RF signal. In this case, the phase of the RF signal at the first upper electrode is shifted by 180 degrees from the phase of the RF signal at the first lower electrode. In block 806, a DC voltage is applied between the deflection electrode of a deflection assembly located downstream of the RF electrode and a blocker. The DC voltage is applied while the ion beam is being transported through the EDMA assembly in order to deflect and block different ion species of the ion beam. In this case, a mass-spectrably bundled ion beam is produced. In particular, a blocker may block the ion beam in a manner that tends to produce a bundled ion beam. On the other hand, the DC voltage, in conjunction with the RF voltage applied to the RF electrode, deflects ions with different masses in different ways. Thereafter, ions of a desired species having a target mass preferentially pass through the EDMA assembly.

[0049]

[0062] In block 808, the bundled mass spectrometry ion beam is received in a dual-channel ESR. The dual-channel ESR includes an upper ESR electrode, a lower ESR electrode, and an intermediate ESR electrode.

[0050]

[0063] In block 810, an accelerating RF voltage is applied to the dual-channel ESR at a second frequency double the first frequency. In this case, the energy dispersion of the mass-spectrably analyzed beam is reduced.

[0051]

[0064] In block 812, the mass-spectrated beam passes through an electrostatic energy filter before colliding with the substrate.

[0052]

[0065] Multiple embodiments offer a first advantage: unlike known beamline ion implanters that use EDMA assemblies and deflection assemblies, they reduce the footprint for generating mass spectrometry ion beams. A further advantage offered by multiple embodiments is the ability to generate reduced energy spread of mass spectrometry ion beams in compact ion beam systems, thanks to ESR assemblies.

[0053]

[0066] While several specific embodiments of the present disclosure have been described herein, the present disclosure is in the broadest scope permitted by the art, and this specification can be read in the same manner as such, and is therefore not limited to these embodiments. Accordingly, the foregoing should not be construed as limiting. Those skilled in the art will anticipate other modifications within the scope of the claims and essence appended herein.

Claims

1. An apparatus comprising an electrodynamic mass spectrometry (EDMA) assembly, wherein the EDMA assembly is A first upper electrode positioned above the beam axis, and The system comprises a first lower electrode positioned below the beam axis, opposite to the first upper electrode, It is arranged to receive a first RF voltage signal at a first frequency, The aforementioned device further, A deflection assembly located downstream of the EDMA assembly, comprising a blocker positioned along the beam axis, and An energy spread reducer (ESR) located downstream of the deflection assembly is configured to receive a second RF voltage signal at a second frequency that is twice the first frequency. An upper ESR electrode positioned above the beam axis, and An ESR apparatus comprising a lower ESR electrode positioned below the beam axis.

2. The energy spread reducer further comprises an intermediate ESR electrode positioned between the upper ESR electrode and the lower ESR electrode, The apparatus according to claim 1, wherein the upper ESR electrode, the intermediate ESR electrode, and the lower ESR electrode form a double channel ESR.

3. The apparatus according to claim 1, wherein the deflection assembly further comprises an upper deflection electrode disposed on the first side of the blocker and a lower deflection electrode disposed on the second side of the blocker.

4. The apparatus according to claim 1, further comprising a focused ion beam assembly positioned upstream of the EDMA assembly.

5. The apparatus according to claim 4, wherein the focusing ion beam assembly comprises an Einzel lens.

6. The apparatus according to claim 4, wherein the focused ion beam assembly comprises a tetrode assembly, and the third lens of the tetrode assembly is positively biased.

7. The apparatus according to claim 1, further comprising a block opening located downstream of the energy spread reducer.

8. An ion beam processing system, An ion source for generating an ion beam as a continuous ion beam, The system comprises an electrodynamic mass spectrometry (EDMA) assembly located downstream of the ion source, and the EDMA assembly is A first upper electrode positioned above the beam axis, and The system comprises a first lower electrode positioned below the beam axis, opposite to the first upper electrode, It is arranged to receive a first RF voltage signal at a first frequency, The ion beam processing system further, A deflection assembly located downstream of the EDMA assembly, comprising a blocker positioned along the beam axis, and An energy spread reducer (ESR) located downstream of the deflection assembly is configured to receive a second RF voltage signal at a second frequency that is twice the first frequency. An upper ESR electrode positioned above the beam axis, and An ion beam processing system equipped with an ESR, comprising a lower ESR electrode positioned below the beam axis.

9. An EDMA power supply is arranged to apply a first RF voltage signal between the first upper electrode and the first lower electrode. A deflection power supply arranged to apply a static bias voltage between the blocker and the deflection assembly, and The ion beam processing system according to claim 8, further comprising an ESR power supply arranged to apply the second RF voltage signal.

10. The energy spread reducer further comprises an intermediate ESR electrode positioned between the upper ESR electrode and the lower ESR electrode, The ion beam processing system according to claim 8, wherein the upper ESR electrode, the intermediate ESR electrode, and the lower ESR electrode form a double-channel ESR.

11. The ion beam processing system according to claim 8, further comprising a focused ion beam assembly positioned upstream of the EDMA assembly.

12. The ion beam processing system according to claim 11, wherein the focusing ion beam assembly comprises an Einzel lens.

13. The ion beam processing system according to claim 11, wherein the focused ion beam assembly comprises a tetrode assembly, and the third lens of the tetrode assembly is positively biased.

14. The ion beam processing system according to claim 8, further comprising an electrostatic energy filter positioned downstream of the EDMA assembly and comprising a plurality of electrodes for changing the propagation direction of the ion beam.

15. The process of guiding an ion beam into an EDMA assembly as a continuous ion beam, wherein the EDMA assembly comprises a first upper electrode and a first lower electrode, While the ion beam is being transported through the EDMA assembly, a first RF voltage signal applied at a first frequency is applied to the ion beam within the EDMA assembly. Using a blocker to block the path of a portion of the ion beam along the beam axis at a downstream position of the EDMA assembly, thereby blocking the path from which a mass-spectrably analyzed bundled ion beam is generated, and A method comprising applying an accelerating RF voltage signal to the mass-spectrated bundled ion beam as the bundled ion beam passes through an energy spreading reducer, wherein the accelerating RF voltage signal is applied at a second frequency which is twice the first frequency.

16. The method according to claim 15, further comprising applying a DC deflection voltage between the blocker and the deflection electrode pair while the ion beam is traversing between the EDMA assembly and the energy spread reducer.

17. The method according to claim 15, wherein the ion beam is provided to the EDMA assembly as a focused ion beam.

18. The aforementioned energy spread reducer is An upper ESR electrode positioned above the beam axis, and The method according to claim 15, further comprising a lower ESR electrode positioned below the beam axis.

19. The method according to claim 18, wherein the energy spread reducer further comprises an intermediate ESR electrode disposed between the upper ESR electrode and the lower ESR electrode.

20. The method according to claim 16, wherein the blocker is at least partially located downstream of the pair of deflection electrodes.

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