Split ring resonator ion beam source

Abstract

Embodiments of charged particle beam systems, components, and methods for extracting charged particles from a gas are described. In a first aspect, a charged particle source includes a resonator. The resonator may include a dielectric substrate defining a first side and a second side, the second side opposite the first side. The resonator may include a first conductive layer disposed on the first side. The first conductive layer may be disposed according to a pattern including a loop portion. The pattern may define a gap in the loop portion of the first conductive layer. The resonator may also include a second conductive layer disposed on the second side. The charged particle source may also include a source electrode. A source electrode may be disposed adjacent the first side. The source electrode may be offset from the dielectric substrate.

Description

Technical Field

[0001] Embodiments of this disclosure relate to charged particle beam systems, and algorithms and methods for operating them. Specifically, some embodiments relate to microwave resonator ion sources for focused ion beam systems. Background Technology

[0002] Miniaturized plasma sources are used in a variety of applications, such as chemical analysis and sterilization. The advantages of miniaturized plasma sources include relatively low power consumption, simple design and manufacturing, mechanical robustness, long lifespan, high non-thermal plasma density, and the ability to operate at atmospheric pressure.

[0003] Miniaturized plasma sources include those based on microstrip open-loop resonators (MSRRs). A traditional MSRR consists of an RF transmission line comprised of a dielectric substrate sandwiched between a metal strip and a metal ground plane. The metal strip is a dipole folded into a circle, with a small gap at both ends that can generate an electric field within the gap. This dipole corresponds to a half-wavelength microwave resonator and can also be used in antenna designs. The dipole is connected to an additional microstrip transmission line, which serves as a feed line to provide the RF power.

[0004] At resonance, the potentials at the two ends of the dipole differ by 180°, which amplifies the electric field amplitude across the dipole by several orders of magnitude. Therefore, at relatively low input power, a large potential difference is generated across the gap, which is used to excite and sustain the plasma. In a conventional MSRR, the electric field in the microstrip line is primarily confined to the dielectric substrate. However, in the gap of an open-loop resonator, the electric field strength between the two ends of the folded dipole rises from the substrate and concentrates on the plane between the two ends of the strip. In a conventional MSRR, the ion acceleration and average ion velocity in the plasma are at least partially reduced as much as possible by using an RF power signal averaging voltage approximately equal to 0V.

[0005] Impedance matching is particularly important in conventional MSRRs because the resonator's characteristic impedance depends on geometric factors such as the spatial offset of the feed line relative to the dipole center and the quality factor of the microstrip line. Furthermore, the impedance characteristics of conventional MSRRs differ significantly between pre- and post-excitation operating conditions (e.g., in the absence and presence of microplasma discharge, respectively). Typically, good matching conditions are achieved using dynamic matching circuitry coupled with an active control system configured to minimize reflected power received at the power source. This system is characterized by its large size, high cost, and greater complexity in design and construction. Summary of the Invention

[0006] Embodiments of charged particle beam systems, components, and methods for extracting charged particles from a gas are described. In a first aspect, the charged particle source includes a resonator. The resonator may include a dielectric substrate defining a first side and a second side, the second side opposite to the first side. The resonator may include a first conductive layer disposed on the first side, the first conductive layer being configured according to a pattern including a ring portion. The pattern may define a gap in the ring portion of the first conductive layer. The pattern may define a first input point in the ring portion at a first fractional position α on the ring portion. The pattern may also define a second input point in the ring portion at a second fractional position β on the ring portion. The resonator may also include a second conductive layer disposed on the second side. The charged particle source may also include a source electrode. The source electrode may be disposed adjacent to the first side. The source electrode may define an aperture. The source electrode may be offset from the first conductive layer. The offset may be defined by a spacer. The spacer may include a dielectric material and / or an insulating material. The spacer may define a conduit. The conduit may form at least a portion of a fluid transport coupling structure. For a given input point in the ring, the fractional position can be the ratio of the length of the first path between the gap and the given input point along the first direction to the length of the second path between the gap and the given input point in a second direction different from the first direction.

[0007] In some embodiments, the charged particle source further includes a radio frequency (RF) power supply operatively coupled to the resonator. A first conduction path from the RF power supply through a first input point is well matched in the absence of discharge. A second conduction path from the RF power supply through a second input point is well matched in the presence of discharge. Well matched may refer to a condition where the reflected power measured at the RF power supply during operation is negligible or substantially zero. The charged particle source may also include control circuitry configured to deliver power from the RF power supply to either the first or second input point based at least in part on discharge ignition between the ring and the source electrode. β may be less than α. The source may be configured to deliver RF power to the ring via the first input point in the absence of discharge and via the second input point in the presence of discharge.

[0008] The control circuit may include a first diode electrically coupled to the ring via a first conduction path and a second diode electrically coupled to the ring via a second conduction path. The control circuit may also include a third diode electrically coupled to the first diode and the first inductor via the first conduction path and a fourth diode electrically coupled to the second diode and the second inductor via the second conduction path. The first, second, third, and / or fourth diodes may be PIN diodes. The first and third diodes may be in opposite directions. The second and fourth diodes may be in opposite directions.

[0009] The control circuit may include a DC voltage source electrically coupled to a first conduction path via a first inductor or electrically coupled to a second conduction path via a second inductor. The charged particle source may also include a DC bias T-shaped element electrically coupled to the first conduction layer, the DC bias T-shaped element including a DC power input and an RF power input, the included components configuring the DC bias T-shaped element to apply a DC bias to the RF power signal, thereby modifying the offset voltage of the RF power signal.

[0010] The pattern can also define a third input point at a third fractional position γ on the ring, located between the first and second input points and relative to the gap.

[0011] In some embodiments, the source electrode is electrically coupled to a reference voltage shared with the second conductive layer. The charged particle source may be operatively coupled to a focused ion beam (FIB) column. The extraction electrode may be disposed on the beam axis downstream of the source electrode.

[0012] The charged particle source may also include a source device. The source device may include a fluid transport coupler, a fluid removal coupler, and an electrical coupler. A resonator may be disposed within the source device and operatively coupled to the electrical coupler. Source electrodes may form part of the source device. The charged particle source may also include a vacuum housing; an isolation support, disposed within the vacuum housing and mechanically coupled to the vacuum housing and the source device, together defining the source chamber and the FIB chamber; the isolation support comprises a material electrically insulating at an applied voltage of approximately ±300 kV DC. The source chamber may be fluidly coupled to the FIB chamber via a bypass conduit.

[0013] In a second aspect, a charged particle beam system includes a source portion. In one or more embodiments, the source portion may include the resonator of the first aspect. The system may include a focused ion beam (FIB) column operatively coupled to the source portion and include a plurality of charged particle optics. The system may also include a vacuum chamber operatively coupled to the FIB column.

[0014] In a third aspect, the charged particle source may include a resonator. The resonator may include a dielectric substrate defining a first side and a second side, the second side opposite to the first side. The resonator may include a first conductive layer disposed on the first side, the first conductive layer being configured according to a pattern including a ring portion defining a gap in the first conductive layer. The resonator may include a second conductive layer disposed on the second side. The charged particle source may also include a source electrode disposed adjacent to the first side. The source electrode may define an aperture. The source electrode may be offset from the dielectric substrate. The offset may be defined by an isolator. The isolator may include a dielectric material and / or an insulating material. The isolator may define a conduit. The conduit may form at least a portion of a fluid transport coupling structure.

[0015] In some embodiments, the charged particle source may further include a radio frequency (RF) power supply operatively coupled to the resonator and calibrated to match the RF power signal impedance in the event of a discharge formed between the loop and the source electrode.

[0016] In some embodiments, the gap may be defined between a first end and a second end of the ring. The hole may be substantially centered on the first end of the ring.

[0017] The ring portion can be a first ring portion. The gap can be a first gap. The pattern may also include a second ring portion defining a second gap. The charged particle source may include an RF power supply, which is operatively coupled to the resonator via the first ring portion or the second ring portion. The RF power supply may be configured to provide a first good-matched impedance condition for a first radio frequency power signal in the presence of a discharge in the first gap. The RF power supply may be configured to provide a second good-matched impedance condition for a second radio frequency power signal in the absence of a discharge in the second gap. The first gap and the second gap may be close to each other. The ring portion may define a tapered portion that narrows toward the respective first gap or second gap. The RF power supply may be coupled to the resonator via a switching circuit. The switching circuit may be configured to couple the first ring portion to the RF power supply in the presence of a discharge, and to couple the second ring portion to the RF power supply in the absence of a discharge.

[0018] In some embodiments, a first ring portion may define a first power injection point. A second ring portion may define a second power injection point. A first gap may be defined in the first ring portion at a first fractional position α relative to the first power injection point. A second gap may be defined in the second ring portion at a fractional position β relative to the second power injection point. For a given input point in the ring portion, the fractional position may be the ratio of a first path length between the gap and the given input point along a first direction to a second path length between the gap and the given input point in a second direction different from the first direction. The first fractional position α and the second fractional position β may be substantially equal.

[0019] In some embodiments, the charged particle source may further include a DC bias T-shaped element electrically coupled to the first ring. The DC bias T-shaped element may further include a DC power input and an RF power input. The DC bias T-shaped element may include components that configure the DC bias T-shaped element to apply a DC bias to the RF power signal, thereby modifying the offset voltage of the RF power signal.

[0020] In some embodiments, the source electrode may be electrically coupled to a reference voltage shared with the second conductive layer. The source electrode may include a foil coupled to a support, with a hole formed in the foil. The hole may be characterized as having a diameter ranging from about 20 μm to about 200 μm, including its subranges, fractions, and interpolations; and an aspect ratio of about 0.05 to about 0.5, including its subranges, fractions, and interpolations.

[0021] The charged particle source can be operatively coupled to a focused ion beam (FIB) column. The FIB column may include an extraction electrode. A resonator may be oriented relative to the extraction electrode such that the source electrode is located between a first side and the extraction electrode. In some embodiments, the charged particle source may also include a source device. The source device may include a source electrode, a fluid transport coupler, a fluid removal coupler, and an electrical coupler. The resonator may be disposed within the source device and operatively coupled to the electrical coupler.

[0022] Fourthly, the charged particle beam system includes a source portion. In one or more embodiments, the source portion may include a resonator as described in the third aspect. The system includes a focused ion beam (FIB) column. The FIB column may be operatively coupled to the source portion and may include a plurality of charged particle optics. The system may also include a vacuum chamber operatively coupled to the FIB column.

[0023] The source portion may also include a source device. The source device may include a dielectric substrate and a housing coupled to the dielectric substrate. The housing may include a source electrode, a fluid transport coupler, a fluid removal coupler, and an electrical coupler operatively coupled to a first conductive layer and / or a second conductive layer via the housing.

[0024] At least a portion of the housing may be coupled to a voltage source. The voltage source may be configured to apply a voltage of about 1 kV to about 350 kV to that portion of the housing. The FIB post may include an extraction electrode. The source portion may be oriented relative to the extraction electrode such that the source electrode is located between the first side and the extraction electrode.

[0025] In some embodiments, the ring portion may be a first ring portion. The pattern may define a resonant multipole structure including the first ring portion. The resonant multipole structure may include a second ring portion. The first and second ring portions may define four gaps between their four ends.

[0026] Fifthly, the spectral source may include charged particle sources from one or more embodiments of the first aspect or one or more embodiments of the third aspect. The spectral source may be configured to introduce an analyte into a discharge region between the resonator and the source electrode, and to generate a discharge including the analyte, thereby directing the characteristic photon flux from the discharge to the spectrometer. The spectrometer may include input optics, diffraction optics, and a detector. The spectrometer may be configured to decompose the characteristic photon flux into one or more component beams from which OES spectral data can be generated.

[0027] Input optics may include a collimator, one or more lenses, and / or one or more filters. In some embodiments, the input optics may include one or more beam splitters and / or one or more polarizers. Diffractive optics may include gratings, mirrors, distributed Bragg reflectors (DBRs), and / or one or more mechanical elements configured to move the diffractive optics relative to one or more other components of the spectrometer. Detectors may include one or more sensors, lateral sensors, and / or electronics configured to generate OES spectral data at least in part based on characteristic photon flux.

[0028] The analyte can be supplied to the discharge region as atomized vapor, as gaseous vapor, and / or as a solid. The source may be equipped with a fluid coupler for introducing and / or removing the analyte from the discharge region. The source may be configured to operate at or near atmospheric pressure, under vacuum, and / or above atmospheric pressure. In some cases, the operating pressure may be at least partially based on the analyte being processed and the corresponding discharge characteristics.

[0029] The gap may be defined within a first conductive layer. This gap may be substantially oriented relative to the source electrode, such that the photon flux emitted from the discharge is transmitted from the source to the input optics of the spectrometer. For this purpose, the source electrode may be, or comprise, a material that is substantially transparent to and conductive to photons within a specific spectral range. The source electrode may include indium tin oxide (ITO). The source may include a transparent portion.

[0030] Sixthly, the spectral source may include charged particle sources from one or more embodiments of the first aspect or one or more embodiments of the third aspect. The spectral source may be configured as a sealed source. The spectral source may be calibrated for use in absorption spectroscopy (OAS) applications and for generating a discharge containing the analyte, thereby directing characteristic photon flux from the discharge to the spectrometer. The spectrometer may include input optics, diffraction optics, and a detector. As part of the OAS procedure, the OAS system may be configured to pass a test photon beam through an analyte cell and a reference photon beam through a reference cell. Optics may be used to prepare the test beam and reference beam, including collimators, beam splitter optics, mirrors, and / or partially transmissive mirrors. One or more optics may be coupled to a movable component. The movable component may include an electric turntable, a stepper motor, or similar devices. Characteristic photons may include photons in the ultraviolet energy range and / or the visible energy range. The source may be configured to generate a discharge favorable for photon emission in the ultraviolet and / or visible spectral ranges.

[0031] In a seventh aspect, the volumetric plasma system includes a charged particle source from one or more embodiments of the first aspect or one or more embodiments of the third aspect. The volumetric plasma system may include a sample locking chamber. The sample locking chamber may be coupled to a vacuum chamber of the charged particle beam system. The sample locking chamber may be reversibly isolated from the vacuum chamber. The sample locking chamber may be reversibly isolated from the vacuum chamber via a movable valve. The valve may be a gate valve. The charged particle source may be disposed in the sample locking chamber. The charged particle source may be disposed in the vacuum chamber. The sample stage of the charged particle beam system may be configured to have a range of motion extending through the sample locking chamber. The sample stage may be configured to have a range of motion extending through the sample locking chamber and through the vacuum chamber. The sample stage may be electrically coupled to a voltage source and may be used as at least a portion of a source electrode. The source electrode may include a substrate. The substrate may be conductive. The substrate may be electrically coupled to the voltage source via the sample stage. The substrate may be coupled to one or more sample manipulation tools. The sample manipulation tool may be coupled to one or more control devices via a vacuum feedthrough. The sample manipulation tool may be configured to couple the substrate to the sample stage.

[0032] The terminology and expressions used herein are descriptive and not restrictive in nature. Their use is not intended to exclude any equivalents of the shown and described features or portions thereof, but rather to facilitate the understanding that various modifications may be possible within the scope of the claimed subject matter. Therefore, it should be understood that although the claimed subject matter has been clearly disclosed through specific embodiments and optional features, modifications and variations of the concepts disclosed herein can be made by those skilled in the art, and such modifications and variations should be considered to fall within the scope of this disclosure as defined by the appended claims. For example, the foregoing aspects and embodiments may be combined with one or more other aspects and / or embodiments of the same or other aspects. Attached Figure Description

[0033] The foregoing aspects and many accompanying advantages of this disclosure will become more readily understood when taken in conjunction with the accompanying drawings and the following detailed description.

[0034] Figure 1 This is a schematic diagram illustrating an exemplary dual-beam system based on some embodiments of the present disclosure.

[0035] Figure 2A This is a schematic diagram illustrating an exemplary ion source based on some embodiments of the present disclosure.

[0036] Figure 2B This is a schematic diagram illustrating an exemplary source device according to some embodiments of the present disclosure.

[0037] Figure 3A This is a schematic diagram illustrating an exemplary ion source based on some embodiments of the present disclosure.

[0038] Figure 3B This is a schematic diagram illustrating an exemplary ion source based on some embodiments of the present disclosure.

[0039] Figure 4A This is an illustration of an exemplary optical emission spectroscopy system (including...) based on some embodiments of this disclosure. Figures 2A-3B A schematic diagram of the ion source in the diagram.

[0040] Figure 4B This is an illustration of an exemplary optical absorption spectroscopy system (including...) based on some embodiments of this disclosure. Figures 2A-3B A schematic diagram of the ion source in the diagram.

[0041] Figure 4C This is an illustration of an exemplary volumetric plasma system (including...) based on some embodiments of this disclosure. Figures 2A-3B A schematic diagram of the ion source in the diagram.

[0042] Figure 4D This is an illustration of an exemplary volumetric plasma system (including...) based on some embodiments of this disclosure. Figures 2A-3B A schematic diagram of the ion source in the diagram.

[0043] Figures 5A-5C This is a illustrative description based on some embodiments of the present disclosure. Figures 2A-3B A schematic diagram of an exemplary ion source (including a single open-ring resonator).

[0044] Figures 6A-6C This is a illustrative description based on some embodiments of the present disclosure. Figures 5A-5C A schematic diagram of an exemplary ion source (including a bias T-shaped element).

[0045] Figures 7A-7C This is a illustrative description based on some embodiments of the present disclosure. Figures 2A-3B A schematic diagram of an exemplary ion source (including a double-opening ring resonator).

[0046] Figures 8A-8B This is a illustrative description based on some embodiments of the present disclosure. Figures 7A-7C A schematic diagram of an exemplary ion source (including a bias T-shaped element).

[0047] Figures 9A-9D This is a illustrative description based on some embodiments of the present disclosure. Figures 2A-3B A schematic diagram of an exemplary ion source (including multiple input points).

[0048] Figures 10A-10D This is a illustrative description based on some embodiments of the present disclosure. Figures 2A-3B A schematic diagram of an exemplary ion source (including a multipole resonant structure).

[0049] Figure 11This is a block flowchart illustrating an exemplary process for extracting an ion beam from a discharge, based on some embodiments of the present disclosure.

[0050] In the accompanying drawings, unless otherwise specified, the same reference numerals denote the same parts in each view. Where appropriate, it is not necessary to label all instances of elements to reduce confusion in the drawings. The drawings are not necessarily drawn to scale, but rather focus on illustrating the principles described. Detailed Implementation

[0051] Although specific embodiments have been illustrated and described, it should be understood that various changes can be made thereto without departing from the spirit and scope of this disclosure. In the following paragraphs, embodiments of charged particle beam systems, components, and methods for extracting ions from gases will be described. For simplicity, embodiments of this disclosure focus on techniques for improved matching and control in different discharge schemes applied in focused ion beam (FIB) instruments. Therefore, the embodiments are not limited to such systems but are contemplated for analytical instrument systems where technical challenges may exist in extracting charged particles from relatively small volumes of gas. In illustrative examples, FIB sources can benefit from miniaturization and circuit design to improve the transition from pre-excitation mode to discharge mode without the use of dynamic matching circuitry. Similarly, the micro-discharge systems of this disclosure can be integrated into optical emission systems, sample introduction and preparation components (e.g., sample lock chambers), or similar devices. While embodiments of this disclosure focus on dual-beam FIB-SEM systems, additional and / or alternative systems are contemplated, including but not limited to single-beam FIB systems, portable ion sources, and optical emission systems where micro-discharges can be used as light sources.

[0052] Embodiments of this disclosure include systems, methods, algorithms, and non-transitory media for extracting ions from a discharge using an open-ring resonator-type plasma source. In illustrative examples, a charged particle source system may include a resonator. The resonator may include a dielectric substrate defining a first side and a second side. The second side may be opposite to the first side. The resonator may include a first conductive layer disposed on the first side. The first conductive layer may be patterned including a ring portion. The ring portion may define a gap in the first conductive layer. The resonator may also include a second conductive layer disposed on the second side. The source system may also include source electrodes. The source electrodes may be disposed adjacent to the first side. The source electrodes may define an aperture. The source electrodes may be offset from the first conductive layer. Embodiments of this disclosure include multiple power input points on a single ring portion, multiple ring portions providing multiple gaps, a bias circuit for applying an offset voltage to an AC power signal (e.g., an RF power signal), and a multi-pole structure configured to reduce or substantially eliminate ion thermalization in the gaps. In this way, the open-ring resonator source disclosed herein can be used as a tunable ion source in charged particle beam systems and other analytical instrument systems, while providing well-matched impedance conditions in both the presence and absence of discharge, without relying on dynamic impedance matching circuits.

[0053] Figure 1 This is a schematic diagram illustrating an exemplary dual-beam system 100 according to some embodiments of the present disclosure. The exemplary system 100 includes an electron source 105, an electron beam column 107, an ion source 110, a focused ion beam (“FIB”) column 111, a gas injection system (“GIS”) 115, a vacuum chamber 120, and a sample stage 125. As shown, the electron beam column 107 is a scanning electron microscope (SEM) column, thereby making the exemplary system 100 correspond to a dual-beam FIB-SEM system. As shown, the electron beam column 107, the FIB column 111, and the GIS 115 are operatively coupled to the vacuum chamber 120, wherein the electron beam column 107 defines a first beam axis A, and the FIB column 111 defines a second beam axis B. As shown, axes A and B converge onto a region of a sample 130, wherein the GIS 115 faces this region of the sample 130 and is configured to direct a gas flow including a precursor into the vacuum chamber. Advantageously, although axis A and axis B can be oriented in different positions, convergence allows the SEM system to image the sample area being processed by FIB.

[0054] Electron source 105 may include one or more emitters configured to generate free electrons and direct them into electron beam column 107. The emitter may include a thermionic emitter, a Schottky emitter, a field emission source emitter, or a combination thereof, operatively coupled to a power system configured to apply a high voltage (e.g., approximately several kilovolts to hundreds of thousands of volts) to the emission region of the emitter material. For example, electron source 105 may include a lanthanum hexaboride (LaB6) emitter crystal to which a high potential is applied to induce electron emission from the tip of the emitter crystal. In this way, the electron beam can be directed into electron beam column 107.

[0055] Electron beam column 107 includes electromagnetic optics (e.g., electrostatic lenses, electromagnetic lenses, monochromators, aberration correctors, etc.) and an aperture, which are configured to shape, focus, defocus, converge, and / or guide the electron beam according to a set of operating parameters, such that the beam is focused onto sample 130. Operating parameters may include beam current, beam energy (e.g., in volts or electron volts), magnification parameters, scanning mode, residence time, and / or one or more pulse parameters. In this way, exemplary system 100 can function as a SEM for imaging portions of sample 130 and / or for electron beam-assisted material deposition on sample 130 (e.g., in conjunction with GIS 115) or for other sample modifications.

[0056] Ion source 110 may include one or more components configured to generate an ion beam and direct ions into FIB column 111. Generally, the ions may include metal ions and / or non-metal ions (e.g., inert gases, halogens, oxygen, nitrogen, etc.). For this purpose, ion source 110 may include a plasma source (e.g., an inductively coupled plasma source or microplasma source as described in this disclosure) and / or a metal ion source (e.g., a liquid metal ion source). In the context of this disclosure, atomic and / or molecular gases and mixtures thereof may serve as plasma precursor gases from which an ion beam can be extracted. Therefore, embodiments of this disclosure relate to systems, components, and methods for exciting and sustaining plasma discharges, and may include related techniques for extracting ions from plasma discharges. In some embodiments, ion source 110 includes a microwave resonator circuit configured to provide well-matched conditions in one or more discharge modes in the presence and / or absence of a plasma discharge. Figures 2A-11 Embodiments of the microwave resonator circuit of this disclosure and its operation are shown in more detail.

[0057] Similar to electron beam column 107, FIB column 111 may include electromagnetic optics (e.g., electrostatic lenses, electromagnetic lenses, monochromators, etc.) and apertures configured to shape, focus, defocus, converge, and guide the ion beam according to a set of operating parameters, such that the beam is focused onto sample 130. Operating parameters may include beam current, beam energy (e.g., in volts or electron volts), amplification parameters, scanning mode, residence time, and / or one or more pulse parameters. In this way, exemplary system 100 can function as a FIB for modifying portions of sample 130 and / or for ion beam-assisted material removal from sample 130 and / or ion beam-assisted material deposition onto the sample (e.g., in conjunction with GIS 115).

[0058] Similar to the energy described above for the electron beam, the ion beam energy can be selected (e.g., by user selection, by a user-initiated algorithm, and / or automatically without user intervention). In some embodiments, additional and / or alternative precursor decomposition mechanisms (e.g., surface activation and / or secondary electron re-emission) can be employed as precursor decomposition mechanisms, thereby allowing the ion beam energy to be determined at least in part based on the relationship between the beam energy, sample material properties, and the energy characteristics of the precursor deposition reaction mechanism. Advantageously, based at least in part on the combined effect of multiple energy transfer paths, ion beam induced deposition can achieve relatively high yields compared to electron beam induced deposition.

[0059] GIS 115 includes multiple components that together allow GIS 115 to generate and direct a gas flow including a precursor into a vacuum chamber. Components of GIS 115 may include a carrier gas inlet, a nozzle 119, and a conduit fluidly coupling the nozzle 119 and a precursor reservoir 117. The precursor reservoir 117 may include a substantially non-reactive container (e.g., a ceramic crucible, a PTFE shell, or a non-reactive metal or alloy, etc.) at least partially exposed to the conduit. In this way, vapor generated by the precursor disposed in the precursor reservoir 117 can be directed to the nozzle and into the vacuum chamber (e.g., by a pressure-driven flow induced by a pressure gradient relative to the vacuum of the vacuum chamber). In some embodiments, GIS 115 includes a carrier gas inlet fluidly coupled to the nozzle 119 via the conduit. In this way, the precursor can be carried in a carrier gas flow and directed to the nozzle and into the vacuum chamber. Additionally and / or alternatively, the precursor may include a gas under standard conditions and may be introduced into GIS 115 via a gas inlet provided as part of GIS 115.

[0060] The operation of one or more components of the exemplary system 100 can be coordinated by control circuitry according to machine-executable instructions (e.g., software, firmware, etc.), which may be stored in a machine-readable storage medium and / or received from an external system via wired and / or wireless communication technologies (e.g., via Wi-Fi or Bluetooth links). For this purpose, components of the exemplary system 100 can be automatic (e.g., operating without human intervention), pseudo-automatic (e.g., operating with limited human intervention to initiate operations, analyze outputs, and confirm them, etc.), or manually operated (e.g., where operations of the exemplary system 100 are performed and / or coordinated by a human user). In the illustrative example, the sample stage 125 can be mechanically coupled to an automated sample stage control mechanism 127, allowing the sample 130 to tilt reversibly relative to beam axes A and B, such that during operation of the corresponding charged particle beam source, the surface of the sample is oriented at a specific angle relative to a given beam axis. In this way, the operation of a given beam source can be coordinated with the operation of the sample stage control mechanism 127. In another example, the detector provided as part of exemplary system 100 can be integrated into a control system configured to manipulate one or more operating parameters of ion source 110 as part of a control scheme to maintain beam brightness at a set point, as detailed in more detail below. Figure 11 As shown.

[0061] Some embodiments of this disclosure omit one or more components of the exemplary system 100. For example, one or more of sources 105 and 110 and / or columns 107 and 111 may be omitted. In illustrative examples, a single-beam FIB system may be configured to perform operations for generating an ion beam. Similarly, multi-beam FIB systems other than dual-beam FIB-SEM (e.g., FIB-laser systems or FIB-SEM systems for which two or more beam axes are not converged in a given region of sample 130) may include the charged particle sources of this disclosure.

[0062] Figure 2A This is a schematic diagram illustrating an exemplary ion source 200 according to some embodiments of the present disclosure. In the following description, reference is made to the ion source moving parts and the FIB column (e.g., Figure 1 The relative position of the moving parts (FIB column 111) in the exemplary ion source 200 is also referred to as an "inverted" design. Therefore, the exemplary ion source 200 can be... Figure 1 An example of an ion source 110, and which can be configured as... Figure 1This is part of an exemplary system 100. An exemplary ion source 200 includes a source device 205, a fluid transport coupler 210, an electrical coupler 215, an optocoupler 220, and a fluid removal coupler 225. The source device 205 includes a resonator 230. The exemplary ion source 200 may include a vacuum housing 235, an isolation support 240, and a bypass conduit 237 configured to maintain a vacuum environment around the source device 205. The exemplary ion source 200 may include a source electrode 231, an extraction electrode 233, and one or more power supply circuits 217. In some embodiments, the extraction electrode 233 is a component of a FIB column and is introduced into the vacuum environment via coupling to the FIB column through the vacuum housing 235.

[0063] Figure 2A A cross-sectional view of an exemplary ion source 200 is shown. For this purpose, some components of the exemplary ion source 200 are at least partially oriented around axis B (e.g., Figure 1 The second axis (B) is rotationally symmetric. Other components are not rotationally symmetric. For example, the isolation support 240 can be a truncated trumpet-shaped rotating solid. Figure 2B As shown, the source device 205 may also be substantially symmetrical about axis B, but other shape factors may also be used, such as those determined by the constraints of the vacuum housing 235.

[0064] Various couplers 210, 215, 220, and 225 can be configured to provide material, energy, and diagnostic capabilities to the source device 205. For example, fluid delivery coupler 210 and fluid removal coupler 225 can be coupled to various fluid handling conduits (e.g., gas-vacuum pass-throughs, liquid / vapor coolant pass-throughs, etc.) and configured to deliver fluid to the vicinity of resonator 230, as detailed in more detail below. Figures 3A-11 As shown. In this document, the term "fluid" can refer to a gas, liquid, or other phase characterized by the following flow tendencies: flowing from a relatively high-pressure region to a relatively low-pressure region, or flowing by means of other mechanisms (e.g., molecular flow). For this purpose, the fluid can be or include a volatile precursor (e.g., vapor) entrained in a carrier gas or a vapor flow in the absence of a carrier gas. Embodiments of this disclosure include various fluid transport couplers 210 and fluid removal couplers 225 specifically designed for different applications. For example, one pair of couplers may be configured to provide a plasma precursor fluid (e.g., a gas mixture, a vapor mixture, etc.) to the resonator 230, and a second pair may be coupled to one or more cooling loops to dissipate heat from the resonator 230 (e.g., using a liquid coolant).

[0065] In some embodiments, the fluid delivery coupler 210 includes a feedthrough 221 configured to establish fluid coupling between a relatively high-pressure environment near the resonator 230 and a fluid supply system outside the vacuum enclosure 235. As an example, the feedthrough 221 may be or may include a capillary or other conduit that allows delivery of plasma precursors to the relatively high-pressure region near the resonator. Similarly, the fluid removal coupler 225 may be coupled to a vacuum system to evacuate the precursors from the vicinity of the resonator 230 to a relatively high vacuum environment and / or maintain the pressure at the outlet of the source device 205. In this way, fluid supplied to the relatively high-pressure environment (e.g., the discharge region) near the resonator 230 is preferentially drawn to the fluid removal coupler 225 rather than to the vacuum environment of the FIB system (e.g., via...). Figure 2B Hole 265).

[0066] Resonator 230 can be electrically coupled to power supply circuit 217 via electrical coupler 215. For example... Figures 4A-10C Specifically, the power supply circuit may include a radio frequency (RF) alternating current (AC) power supply and / or a direct current (DC) power supply. In an illustrative example, source device 205 may include a microwave amplifier and a DC bias circuit. The microwave amplifier may consume power from about 0.5 watts to about 30 watts, including its sub-ranges, fractions, and interpolations. The power consumed by the microwave amplifier may be at least partially based on the operating parameters of the plasma source (e.g., power delivery to the plasma). In some embodiments, control circuitry (e.g., a microcontroller coupled to the power supply circuitry) and the DC bias power supply are configured together to consume power from about 0.1 watts to about 10 watts, including its sub-ranges, fractions, and interpolations.

[0067] To facilitate the operation of resonator 230 as an RF plasma source, one or more forms of RF shielding (e.g., Faraday shielding) can be provided to protect the electrical components of the exemplary ion source 200 from electromagnetic interference (EMI). For example, components of the electrocoupler 215 and the RF power supply and / or resonator (e.g., Figure 7C , Figure 8B and Figure 9C (Electronic components provided on the resonator board shown). This shielding can also be used to reduce interference between DC components of the exemplary ion source 200 (e.g., source electrode 231 and / or DC power supply circuitry), as detailed in more detail... Figures 6A-6C As shown.

[0068] In some embodiments, the source device 205 is shaped to accommodate an isolation bracket 240 to shield the electroactive elements of the exemplary ion source 200 from the triple connection point formed between the isolation bracket 240, the source device 205, and the surrounding vacuum environment. Without being constrained by any particular physical mechanism or interpretation, shielding the triple connection point in this manner can reduce the likelihood of electronic surface flashover or other electrical breakdown modes that may occur when the grounded surface is separated from the energized surface by an electrical insulator. In the context of this disclosure, the relatively high voltage applied to the source electrode 231 and / or the extraction electrode 233 can be shielded from the isolation bracket 240 at the point where it intersects with the source device 205. These shapes may include ridges, ribs, baffles, or other shapes for physically shielding the energized components of the exemplary ion source 200 from the grounded portion of the exemplary ion source 200.

[0069] Source device 205 may include a housing, such as a enclosure equipped with coupling interfaces for various input / output interfaces (e.g., fluid, optical, electrical, etc.), which at least partially isolates the resonator from the relatively high-pressure environment near the resonator compared to the vacuum environment surrounding source device 205. For this purpose, resonator 230 may be at least partially housed within the housing of source device 205, but may also serve as part of the housing, for example, where the support or substrate of resonator 230 isolates the relatively high-pressure environment from the vacuum environment (e.g., in an "inverted" design, such as...). Figure 3B As shown). Figures 2B-3B Specifically, the source device 205 may include an isolation plate disposed between the resonator 230 and the source electrode 231, such that... Figure 2A The various conduits and couplers described herein can be disposed within the isolator or resonator 230, rather than within a separate housing that also houses the resonator 230.

[0070] Figure 2B This is a schematic diagram illustrating an exemplary source device 250 according to some embodiments of the present disclosure. The exemplary source device 250 is... Figure 2A An embodiment of source device 205. Exemplary source device 250 includes an electrical coupler 215 (e.g., as a shielded coaxial coupler) at least partially disposed within a shielded housing 255, a resonator 230, and a source electrode 231. Exemplary source device 250 includes a spacer 275 disposed between the resonator 230 and the source electrode 231. Figure 2B The configuration shown is referred to as the "floating" design of the source device 205, and... Figure 2A In contrast to the "inverted" design, the latter will... Figure 3A Further details will be provided later.

[0071] Extraction electrode 233 is shown to be substantially identical to the features of source device 250, which together at least partially define Figure 2A The axis shown (e.g., Figure 2A(Axis B). For example, resonator 230 may define an aperture 260 that can serve as a fluid transport coupler 210. To this end, embodiments of this disclosure include a relatively high-voltage region outside the source device 250, which drives a plasma precursor gas flow 280 into a discharge region between the resonator 230 and the source electrode.

[0072] Source electrode 231 may define a charged particle extraction aperture 265 positioned relative to extraction electrode 233 such that an extraction electric field emanating from the extraction electrode can draw charged particles (e.g., positive ions, negative ions, etc.) from the plasma generated in the discharge region into the FIB column. Extraction aperture 265 may be defined in foil 270 and at least partially fused to or formed from the substrate material of source electrode 231. For this purpose, source electrode 231 may comprise one, two, or more materials electrically coupled to each other (e.g., by welding or other techniques).

[0073] The aperture 265 can be characterized as having a diameter ranging from about 20 μm to about 200 μm, including its subranges, fractions, and interpolated values; and an aspect ratio of about 0.05 to about 0.5, including its subranges, fractions, and interpolated values. Generally, the diameter of the aperture 265 may depend at least in part on the source beam current. When using a higher beam current, a larger aperture can be defined in the source electrode 231.

[0074] Advantageously, including the foil 270 as part of the source electrode allows the extraction aperture 265 to use a smaller diameter for a given aspect ratio, which in turn improves brightness and reduces the flow rate of neutral particles (e.g., vapor particles, gas particles, etc.) entering the vacuum environment through the extraction aperture 265. Furthermore, where the mean free path of ions in the vacuum environment may be greater than the diameter of the extraction aperture 265, the relatively smaller aspect ratio reduces the likelihood of ion recombination on the conductive surface of the extraction aperture 265.

[0075] The isolator 275 may be or include a substantially insulating material and / or a dielectric material, configured to offset the resonator 230 from the source electrode 231, thereby defining a discharge volume from which charged particles are extracted toward the FIB pillar. In some embodiments, the isolator 275 may be omitted, wherein the offset between the resonator 230 and one or more components (e.g., foil 270) of the source electrode 231 is defined by one or more retaining elements, such as housing 255 and isolation support 240.

[0076] Figure 3A This is a schematic diagram illustrating an exemplary ion source 300 component according to some embodiments of the present disclosure. The component shown is configured as part of an exemplary ion source 300 in a "floating" design, wherein a plasma precursor gas flow 301 is laterally introduced into a resonator (e.g., Figures 2A-2BThe resonator 230), for example via a hole in the resonator formed in the substrate 305 of the resonator 230 or other fluid transport coupling structure (e.g., Figure 2A Coupler 210). An exemplary ion source 300 includes a resonator 230, a source electrode 330, an extraction electrode 335, an isolator 340, an RF power supply 345, a DC power supply 350, and a ground terminal 355. The resonator 230 includes a substrate 305, a first conductive layer 320, and a second conductive layer 325. The resonator 230 defines a hole 321 that is substantially aligned with corresponding holes 331 and 337 in the source electrode 330 and the extraction electrode 335, respectively (e.g., coupler 210). Figure 2B Hole 260).

[0077] The discussion of the components of the exemplary ion source 300 focuses on the electrical subsystem. Therefore, Figure 3A One or more components of the exemplary ion source 300 are omitted; reference will be made to... Figure 2A These components will be discussed in more detail. The substrate 305 may be or may include a dielectric material, such as a ceramic material (e.g., quartz, silicon oxide, titanium oxide, etc.) or other insulating dielectric material. The substrate 305 may define a first side 310 and a second side 315 opposite to the first side 310. A first conductive layer 320, configured to carry an alternating current (AC) signal (e.g., an RF signal from about 0.5 GHz to about 6.0 GHz, including its subranges, fractions, and interpolations), may be disposed on the first side 310 and facing the source electrode 330. In some embodiments, the AC signal may include an RF signal with a frequency from about 0.4 to about 2.4 GHz (including its subranges, fractions, and interpolations). A second conductive layer 325 may be disposed on the second side 315. The second conductive layer 325 may be configured to be electrically coupled to a ground terminal 355. Similarly, the source electrode 330 may be coupled to the ground terminal 355, but may also be biased relative to the second conductive layer 325. Extraction electrode 335 can generate a bias voltage relative to source electrode 330, for example by applying a DC bias voltage applied by DC power supply 350.

[0078] In some embodiments, the relative ground terminal 355 may be a reference voltage rather than a true ground potential. For example, the relative ground terminal 355 may correspond to a so-called "common" voltage applied to the components of the pillar as part of improving the performance of the charged particle beam source (e.g., reducing aberrations and improving spot size). For this purpose, the relative ground terminal 355 may be a positive or negative voltage on the order of about 0V to about 100kV (including its fractions, sub-ranges, and interpolations). In illustrative examples, the magnitude of the relative ground terminal 355 may be about 0.5kV to about 30kV, including its sub-ranges, fractions, and interpolations.

[0079] Figure 3B This is a schematic diagram illustrating an exemplary ion source 360 ​​component according to some embodiments of this disclosure. Figure 3A Similar to the discussion of the exemplary ion source 360 ​​components, the focus is on the electrical subsystem. Therefore, Figure 3B One or more components of the exemplary ion source 360 ​​are omitted; these components will be referred to... Figure 2A A more detailed discussion follows. The components shown are suitable for ion sources configured with an "inverted" design, where the plasma precursor gas flow 361 is substantially parallel to the resonator (e.g., Figures 2A-2B The direction of the resonator 230 is introduced, for example, through a conduit 365 formed in the isolation sheet 340 or other fluid transport coupling structure of the resonator (e.g., Figure 2A Coupler 210). An exemplary ion source 360 ​​includes a resonator 230, a source electrode 330, an extraction electrode 335, an isolator 340, an RF power supply 345, a DC power supply 350, and a ground terminal 355. The resonator 230 includes a substrate 305, a first conductive layer 320, and a second conductive layer 325. The resonator 230 defines a hole 321 that is substantially aligned with corresponding holes 331 and 337 in the source electrode 330 and the extraction electrode 335, respectively (e.g., Figure 2B Hole 260).

[0080] Figure 3B The “inverted” design shown is characterized by a discharge region formed between the source electrode 330 and the resonator 230, thereby allowing the first conductive layer 320 to be disposed on the substrate 305 according to a pattern, as detailed below. Figures 4A-10D As shown. The pattern includes a ring (see illustration and description in subsequent figures) that defines a gap 370 between a first end 322 and a second end 323 of the ring. Figure 3A In contrast to the “floating” design, the exemplary ion source 360 ​​omits the aperture formed through the substrate 305 and the second conductive layer 325. In some embodiments, the source electrode 330 is configured such that the extraction aperture 331 is oriented above the first end 322 or the second end 323, such that the axis B of the exemplary ion source 360 ​​is offset relative to the geometric center of the gap 370. Advantageously, orienting the axis B substantially aligned with the first end 322 or the second end 323 can improve the performance of the exemplary ion source 360 ​​in terms of one or more characteristics of the source. For example, this arrangement can increase the brightness of the source, the power efficiency of the source, the operating pressure of the source, and other benefits, relative to a configuration in which the extraction aperture 331 is substantially centered above the gap 370. Unrestricted by any particular physical phenomenon or mechanism of action, the described technical advantages may derive at least in part from the spatial variation of the ion density, which results in a relatively higher ion density near the first end 322 and / or the second end 323 compared to the geometric center of the gap 370.

[0081] Extraction hole 331 can be formed in the foil 333 portion of source electrode 330, as detailed below. Figures 2A-2BAs shown. Various techniques, including ion beam patterning, can be used to form the apertures 331 in the foil 333. For example, the foil 333 may include a plurality of apertures 331 and may be formed after the exemplary ion source 360 ​​has been at least partially assembled. Advantageously, the alignment accuracy of the extraction apertures 331 and certain portions of the resonator 230 can be improved where there may be relatively high manufacturing variability in one or more components of the exemplary ion source.

[0082] Figure 4A An exemplary optical emission spectroscopy system 400 (including...) is illustrated according to some embodiments of this disclosure. Figures 2A-3B A schematic diagram illustrating the operation of an embodiment of an ion source. An exemplary optical emission spectroscopy (OES) system 400 is configured to introduce an analyte into a discharge region between a resonator and a source electrode, generating a plasma discharge 405 comprising the analyte, and the characteristic photon flux (φ) generated by the discharge 405. OES The composite photon beam 430 is directed into spectrometer 410. Spectrometer 410 includes input optics 415 (e.g., collimator, one or more lenses, etc.), diffraction optics 420 (e.g., grating, mirror, distributed Bragg reflector (DBR), etc.), and detectors 425 (e.g., a row of sensors, laterally moving sensors, etc.), which together decompose the composite photon beam 430 into one or more component beams 435 from which OES spectral data can be generated.

[0083] exist Figure 4A In the illustrated OES configuration, the analyte can be provided to the discharge region using one or more techniques, including as an atomized vapor (e.g., for liquid analytes), as a gaseous vapor, and / or as a solid (e.g., as a crystalline solid or other powder form). For this purpose, the ion source 440 is equipped with a fluid coupler 407 for introducing and / or removing the analyte from the discharge region. Advantageously, for OES operation, the exemplary system 400 can be configured to operate at or near atmospheric pressure, under vacuum, or at pressures above atmospheric pressure. In some cases, the operating pressure may be at least partially based on the properties of the analyte being processed and the corresponding discharge characteristics. For example, for analytes with relatively high ionization threshold energies and that emit characteristic photons at relatively high plasma pressures, operating the exemplary system 400 at near or above atmospheric pressure and relatively high plasma power may benefit them. Conversely, if the analyte readily decomposes at high ionization fractions (e.g., in thermal plasma), operating in an environment with a relatively high proportion of neutral gas and relatively low plasma power may benefit the exemplary system.

[0084] In the exemplary system 400, the ion source 440 is Figure 2A and Figure 3BAn example of an "inverted" design is provided, in which the resonator 445 omits the aperture formed through the first conductive layer 450. A gap 455 defined in the first conductive layer 450 is oriented substantially relative to the source electrode 460, such that the photon flux emitted from the discharge 405 is transmitted from the ion source 440 to the input optics 415 of the spectrometer 410. For this purpose, the source electrode 460 may be, or comprise, a material that is substantially transparent and conductive to photons in a specific spectral range (e.g., ultraviolet, visible, infrared, etc.). Examples of such materials include indium tin oxide (ITO). The ion source 440 includes a transparent portion 465 for this purpose.

[0085] An embodiment of exemplary system 400 omits the source electrode and instead relies on RF energy supplied by RF power supply 470 via electrical coupler 471 to generate and sustain discharge 405, as detailed below. Figures 5A-11 As shown. The source electrode 460 can improve the performance of the ion source 440 by allowing control of the discharge volume, for example, by expanding the discharge volume into the space between the source electrode 460 and the first conductive layer 450. In turn, the source electrode 460 can also compress the discharge volume, thereby increasing the plasma density and enhancing the photon emission of some analytes.

[0086] Figure 4B An exemplary optical absorption spectroscopy (OAS) system 475 (including...) is illustrated according to some embodiments of this disclosure. Figures 2A-3B A schematic diagram illustrating the operation of an embodiment of the ion source in the exemplary system 475. The ion source 440 of the exemplary system 475 includes... Figure 4A The same or similar internal components and power supply system are shown. Fluid coupler 407 is omitted in this description to focus on the optical aspects. However, in some embodiments, fluid coupler 407 may be included, or it may be omitted entirely, for example, in the case where the ion source 440 is configured as a sealed light source (e.g., a calibrated light source) for OAS applications. In this way, the exemplary system 475 includes... Figure 4AOptical elements not present in the exemplary system 400, such as beam splitter optics 480, may be or include mirrors, partially transmitted mirrors, etc., mounted on a turntable, which configure the exemplary system 475 to allow a test photon beam to pass through an analyte cell 485 and a reference photon beam to pass through a reference cell 487, for example, as part of an OAS procedure. The exemplary system 475 is illustrated with separate sample cells 485 and 487 for use in a calibrated OAS system usable for unknown samples. Embodiments of this disclosure may omit one or more of the illustrated elements, for example, when the system is configured for a known analyte (e.g., as part of a quality control procedure), so that the reference beam path can be omitted. In some embodiments, the exemplary system 475 may be configured as a UV-Vis OAS system, in which case the ion source 440 may be configured to generate a discharge 405 that facilitates the emission of photons in the UV-Vis spectral range (e.g., using mercury vapor to obtain UV photons).

[0087] Figures 4C-4D The exemplary volumetric plasma system 490 (including...) is illustrated with reference to some embodiments of this disclosure. Figures 2A-3B A schematic diagram illustrating the operation of an embodiment of the ion source. The exemplary system 490 is configured to expose sample 130 to discharge 405, as... Figure 1 Specifically, as part of one or more procedures for sample preparation to be introduced into the vacuum chamber 120 of the exemplary system 100 (e.g., coupled to the sample stage 125). Examples of such procedures include, but are not limited to, volumetric plasma cleaning, ion etching, electron etching, plasma-based coating, ion sputtering, etc. The exemplary system 490 includes a sample locking chamber 491 isolated from the vacuum chamber 120 by a valve 493 (e.g., a gate valve, etc.), in which an ion source 440 is disposed, and a sample 130 is disposed on a conductive substrate 460, which at least partially acts as a source electrode (e.g., a short column or other sample holder) when electrically coupled to a ground terminal or to a DC voltage source. The sample 130 can be disposed in the ion source 440 using one or more sample manipulation tools 497 via a vacuum feedthrough 499 that allows the sample 130 to be exposed to a discharge 405 and subsequently transferred to the sample stage 125. Alternatively, the sample stage 125 can be configured to extend its range of movement beyond the sample locking chamber 491 and / or through the vacuum chamber 120. In this way, sample 130 can be coupled to stage 125 (e.g., via substrate 460), allowing stage 125 to be moved to a clean position different from the imaging position of the charged particle microscope, such as... Figure 4D As shown. In this case, the cleaning location can be in the vacuum chamber 120 or in the sample injection locking chamber 491, making the cleaning process (e.g., Figure 4C The exposure to the generated plasma shown can be at a location far from the beam axis of the charged particle beam column and sensitive optical elements (such as...). Figure 1 The movement of sample 130 is implemented via axes A and B. In some embodiments, the movement of sample 130 is achieved in an automatic or pseudo-automatic manner, but it can also be achieved manually.

[0088] Figures 5A-5C This is a schematic diagram illustrating an exemplary resonator 500 component according to some embodiments of the present disclosure, representing... Figures 2A-4C The ion source embodiment includes a single open-ring resonator. The discussion of the exemplary resonator 500 components focuses on the patterning of the resonator 500 elements and the electrical subsystem electrically coupled to them. For this purpose, in Figures 5A-5C One or more components of an exemplary ion source are omitted from the text; these components will be referred to... Figures 2A-4C For a more detailed discussion, an exemplary resonator 500 includes a substrate 505. The substrate 505 defines a first side 507 and a second side 509. The exemplary resonator 500 includes a first conductive layer 510 disposed on the first side 507. The first conductive layer 510 is configured according to a pattern including a ring portion 515. The pattern also defines a gap 520 in the ring portion 515 of the first conductive layer 510. The second side 509 has two substantially planes opposite the first side 507 relative to the substrate 505. The exemplary resonator 500 includes a second conductive layer 525 disposed on the second side 509.

[0089] An exemplary resonator 500 is shown as Figure 2A and Figure 3B An embodiment of the “inverted” design. For this purpose, the exemplary resonator 500 omits the hole formed through the substrate 505. However, in some embodiments, the substrate 505 defines a hole extending from the first side 507 to the second side 509. The hole may be defined in the substrate 505 at a location substantially the same as the gap 520 (e.g., as part of a “floating” design), but it may also be defined in other locations, such as within the circumference of the ring 515, outside the ring 515, etc. In this way, the hole can be used as a fluid transport coupler (e.g., Figure 2A A fluid transport coupler 210, through which one or more precursors 530 can be transported to the vicinity of the gap 520. Figure 2A or Figure 3B In the “inverted” design, the precursor flow can be substantially parallel to the first side 507. In some embodiments, a fluid transport coupler may be included at a location away from the gap 520, such that the precursor 530 can be transported via the substrate 505 and / or the second conductive layer 525, while still maintaining a flow profile substantially parallel to the first side 507 near the gap 520.

[0090] Figure 5AThe ring portion 515 is generally circular, but alternative shapes and / or shape factors may be used, at least in part due to constraints such as geometrical limitations imposed by the housing and the correlation between the ring shape and the operating frequency of the AC power signal used to excite and sustain the discharge. In this way, the radius of the ring portion 515 may depend at least in part on the angular position θ relative to the input point 535. Without being constrained by any particular physical mechanism or operating principle, the pattern of the first conductive layer 510 disposed on the first side 507 may be at least in part based on the operating frequency of the exemplary resonator 500.

[0091] For example, the pattern can define the input point 535 in the ring 515 at a first fractional position α on the ring 515. Figure 5B As shown, the fractional position α is the ratio of the first path length S1 between the gap 520 and the input point 535 in a first direction to the second path length S2 between the gap 520 and the input point 535 in a second direction different from the first direction. For a substantially circular ring 515, the fractional position α may be related to an angle (e.g., 360 degrees or 2π radians) (but an angle description may be less meaningful for non-circular patterns of the ring 515, e.g., in a runway-shaped ring 515 or other configurations where the radius of the shape is a function of angle θ), for which rays extending from the input point 535 and the gap 520 may not intersect at the geometric center of the ring 515.

[0092] In the general formula, the fractional position α can correspond to the mathematical formula. When S1 = 0, the value α will be returned as 0; when S1 = πr, the value will be returned as 1; and when S1 = 2πr, the value will be returned as ∞, where θ = 0, π, and 2π respectively, and r is the radius of the ring in the circular design. For the non-circular ring 515, the values ​​of S1, S2, S3, etc., can be defined without referring to the radius.

[0093] Although the value ∞ has no physical meaning, the mathematical formula above shows that when the value of the fractional position is greater than 1, its corresponding position on ring 515 will cause θ to be negative, while the configuration of input point 535 relative to gap 520 still remains functional. In this way, a given fractional position can correspond to two well-matched configurations. In some embodiments, for a given set of operating parameters and plasma conditions, fractional position α values ​​between approximately -1 and approximately 1 can effectively provide a well-matched resonator 500. For example, in a no-discharge state (such as pre-ignition conditions), when the value of the fractional position is greater than approximately 0.4 (e.g., approaching 1 or approximately equal to 1), two functional configurations are produced, corresponding to a positive value of θ and a corresponding negative value of θ, respectively. At least for this reason, the value of the fractional position α can be represented as a positive value derived using the magnitude (e.g., absolute value) of θ and / or the unsigned values ​​of S1 and S2. In other words, the “direction” of the signed θ can be understood as defined relative to input point 535 or gap 520. In some embodiments, for example, if fractional position 1 corresponds to θ = When a typical 50Ω impedance hardware is used in the power supply circuit driving the resonator 500, the power transfer to the gap 520 may be relatively poor, which is related to the fact that the input impedance of the resonator 500 approaches zero.

[0094] In the context of the exemplary resonator 500, the operating frequency refers to the characteristic frequency of the AC power signal that can be supplied to the ring 515 by the power supply circuit, such as... Figure 5C As shown, the power supply circuit may include an RF power supply 545 coupled to a ring 515 via an electrical coupler 540 and electrically contacting an input point 535. In this configuration, the RF power supply 545 is operatively coupled to the resonator 500 and configured to generate different power signals, at least in part, based on the presence or absence of a discharge 550. For example, a first power signal may be provided to the first conductive layer 510, which remains well-matched in the absence of a discharge and is configured to excite the discharge 550; subsequently, one or more adjustments are performed by power electronics as a method to reduce and / or substantially eliminate reflected power when discharge volume conditions change. The exemplary resonator 500, provided with a single input point 353, relies on modifying the impedance matching network to adapt to changes in reflected power without damaging the microwave amplifier.

[0095] Advantageously, the embodiments of this disclosure shown in the following figures are configured to provide well-matched impedance conditions without relying on a dynamic matching network. In this context, the term "well-matched" refers to a condition where the reflected power measured at the RF power supply is negligible or substantially zero during operation using a given power signal. An exemplary resonator 500 may be driven by an RF power supply 545, which is part of an ion beam source, such as... Figures 2A-3BSpecifically, an active electrode 555 and an extraction electrode 560 are provided for directing the ion beam toward a FIB column (e.g., ...). Figure 1 Extracted from FIB column 111.

[0096] Figures 6A-6C This is a schematic diagram illustrating an exemplary resonator 600 (including a bias T-shaped member 640) component according to some embodiments of the present disclosure, representing Figures 2A-5C The ion source embodiment includes a single open-ring resonator. The discussion of the exemplary resonator 600 components focuses on the patterning of the resonator 600 elements and the electrical subsystem electrically coupled to them. For this purpose, in Figures 6A-6C One or more components of an exemplary ion source are omitted from the text; these components will be referred to... Figures 2A-5C For a more detailed discussion, an exemplary resonator 600 includes a substrate 605. The substrate 605 defines a first side 607 and a second side 609. The exemplary resonator 600 includes a first conductive layer 610 disposed on the first side 607. The first conductive layer 610 is configured according to a pattern including a ring portion 615. The pattern also defines a gap 620 in the ring portion 615 of the first conductive layer 610, which is exposed to a precursor provided by one or more flows 630 of a precursor fluid (e.g., gas, vapor, etc.). The second side 609 has two substantially planes opposite the first side 607 relative to the substrate 605. The exemplary resonator 600 includes a second conductive layer 625 disposed on the second side 609.

[0097] The biased T-shaped member 640 can form part of the first conductive layer 610, such as Figures 6A-6B As shown, it can also be a separate conductive element electrically coupled to the first conductive layer 610 at input point 635 via an electrical coupler 645, such as... Figure 6C As shown. The bias T-shaped member 640 can enable the inclusion of an exemplary resonator 600 (e.g., its electrical components in...) Figure 6C The ion source (described in the text) is capable of modulating the offset voltage of the RF power signal supplied to the first conductive layer 610. In this context, the offset voltage refers to the voltage that alters the average voltage of the RF power signal, and it can be measured in various ways (e.g., average voltage, etc.). Advantageously, it has been shown that applying a bias voltage (e.g., a DC bias voltage generated by a DC power supply 650) to the RF power signal generated by the RF power supply 655 improves the performance of the resonator of this disclosure as an ion source, at least in part based on measurements of increased ion flux through the source electrode 660 and / or extraction electrode 665 for a given RF power and substantially consistent other parameters.

[0098] Figures 7A-7C This is a schematic diagram illustrating an exemplary resonator 700 (including a plurality of ring portions 715) according to some embodiments of the present disclosure, representing Figures 2A-5CAn ion source embodiment is described. The discussion of the exemplary resonator 700 components focuses on the patterning of the exemplary resonator 700 elements and the electrical subsystems electrically coupled to them. Therefore, in... Figures 7A-7C One or more components of an exemplary ion source are omitted from the text; these components will be referred to... Figures 2A-5C For a more detailed discussion, an exemplary resonator 700 includes a substrate 705. The substrate 705 defines a first side 707 and a second side 709. The exemplary resonator 700 includes a first conductive layer 710 disposed on the first side 707. The first conductive layer 710 is configured according to a pattern including a first ring portion 715-1 and a second ring portion 715-2. The pattern also defines a gap 720-1 in the first ring portion 715-1 and a gap 720-2 in the second ring portion 715-2 of the first conductive layer 710. The second side 709 has two substantially planes opposite the substrate 705 to the first side 707. The exemplary resonator 700 includes a second conductive layer 725 disposed on the second side 709. (Reference) Figures 5A-5C The resonator shown has a first ring 715-1 defining a first gap 720-1 at a first fractional position α. ​​A second ring 715-2 defines a second gap 720-2 at a second fractional position β. The values ​​of the corresponding fractional positions α and β can be the same or different. In some embodiments, one or more dimensional features of the first ring 715-1 and the second ring 715-2 can differ, such as the thickness of the first conductive layer 710 in the corresponding ring 715. For example, the thickness of the first conductive layer 710 in the first ring 715-1 can be greater than or less than the thickness of the second ring 715-2, utilizing this thickness difference to compensate for the effect of the fractional position on the characteristic impedance of the corresponding ring 715. In some embodiments, one or more rings 715 may include a tapered portion near the corresponding gap 720, such as... Figure 7A As shown, at the first gap 720-1, it gradually tapers at the first end 721 and the second end 723. Without being limited by a specific physical mechanism or working principle, making the ring 715 gradually taper allows the discharge to form closer to the corresponding gap of the corresponding ring 715, as a method to improve the transfer of discharge between different rings 715, thereby maintaining a good impedance matching condition.

[0099] In serving as the ion source of this disclosure (e.g., Figure 1During operation of the ion source 110, the exemplary resonator can switch between two or more operating modes. A first mode is characterized by a set of operating parameters (e.g., operating pressure, gas composition, RF power signal, etc.) configured to promote the excitation of a discharge in a first gap 720-1. A second mode is characterized by a set of operating parameters configured to maintain a discharge in a second gap 720-2. For this purpose, the exemplary resonator 700 can be configured to excite a discharge in the first gap 720-1 by operating in the second mode, and to maintain and / or sustain a discharge in the second gap 720-2 by operating in the first mode, at least in part based on the switching between the first and second modes (e.g., in response to the excitation of a discharge), as detailed in more detail below. Figure 11 As shown.

[0100] The corresponding fractional positions α and β can be defined so that a single RF power supply 655 ( Figure 7C As shown, well-matched impedance conditions can be provided even with and / or without discharge in the first gap 720-1 and / or the second gap 720-2. In some embodiments, fractional positions α and β can be defined to bring gaps 720 close to each other, while the corresponding input point 735 is defined taking into account the geometric constraints of the resonator 700 (e.g., packaging constraints, shielding requirements, etc.). Figures 5A-5C As shown, the fractional positions α and β can be values ​​in the range of approximately 0 to approximately 1, including their fractions, interpolated values, and subranges. Values ​​in the range of approximately 0.4 to approximately 1 are used in the first operating mode, and values ​​in the range of approximately 0 to approximately 1 are used in the second operating mode, including their fractions, interpolated values, and subranges. Corresponding "negative value" configurations may also occur, such as... Figures 5A-5B As shown. In some embodiments, the fraction position value of the second mode is smaller than the fraction position value of the first mode.

[0101] In some embodiments, the exemplary resonator is electrically coupled to one or more RF power supplies 750 via a respective electrical coupler 745, such as Figures 7B-7C As shown. Separate RF power supplies can be used to reduce the need for dynamic matching circuitry, each configured to generate a specific power signal for one of the operating modes. Compared to a system including a switching circuit 755 (configured to direct the RF power signal to a first input point 735-1 or a second input point 735-2 by reversibly coupling power supply 750 to a first ring 715-1 or a second ring 715-2, at least in part based on one or more characteristics of the operating conditions of the exemplary resonator 700, such as the presence or absence of discharge), this method of providing well-matched impedance conditions for each mode increases the cost of the ion source.

[0102] In an illustrative example, the switching circuit 755 may include electrical components that together respond to changes in current and / or reflected power from the first ring 715-1 (e.g., ignition indicating a discharge) to switch to the second input point 735-2. In this case, the overall configuration of the exemplary resonator 700 (e.g., the design of the pattern forming the first conductive layer 710) allows the RF power supply 750 to provide a substantially consistent RF power signal to the second ring 715-2 via the second input point 735-2, such that a discharge can be ignited in the first gap 720-1 and can migrate to the second gap 720-2. In the presence of a discharge, the switching circuit 755 may couple the RF power supply 750 to the second ring 715-2 via the second input point 735-2. This method of using the switching circuit 755 and multiple rings 715 can reduce the need for dynamic power electronics (e.g., complex RF power supplies, matching circuits, large heat sinks, etc.) and enables embodiments of this disclosure to achieve at least the advantages of robustness, low complexity, low cost, and small physical size compared to other ion beam source systems. Significant improvements in power consumption, gas flow rate, cost, and manufacturing complexity compared to typical FIB ion source technologies (such as ICP) further enhance these advantages.

[0103] Figures 8A-8B This is a schematic diagram illustrating an exemplary resonator 800 (including a plurality of ring portions 815) according to some embodiments of the present disclosure, representing Figures 7A-7C The ion source embodiment includes a bias T-shaped element 820. Figures 6A-6C The specific bias T-shaped element 820 shown can improve the performance of the exemplary resonator 800 as an ion source for FIB applications. This improvement can be based at least in part on the voltage offset of the RF power signal used to modulate and / or maintain the discharge (from which ions are extracted), as detailed in more detail... Figures 2A-7C As shown. The discussion of the exemplary resonator 800 components focuses on the patterning of the exemplary resonator 800 elements and the electrical subsystem electrically coupled to them. For this purpose, in Figures 8A-8B One or more components of an exemplary ion source are omitted from the text; these components will be referred to... Figure 2A-7C A more detailed discussion is needed. Furthermore, not all examples are listed. Figures 2A-7C Some of the elements shown (e.g., Figure 7A The second conductive layer 725 is used to focus on describing the bias T-shaped element 820 and the multi-ring pattern.

[0104] An exemplary resonator 800 includes a substrate 805 having a conductive layer 810 disposed on one side of the substrate 805. The conductive layer 810 is configured according to a pattern defining a first ring portion 815-1 and a second ring portion 815-2. A first gap 817-1 is defined in the first ring portion 815-1, and a second gap 817-2 is defined in the second ring portion 815-2. A bias T-shaped member 820 is electrically coupled to the second ring portion 815-2 via a second input point 825-2. The bias T-shaped member 820, the second input point 825-2, and the first input point 825-1 are electrically coupled to corresponding electrical couplers 830, as detailed in more detail below. Figures 2A-2B As shown. The first ring portion 815-1 exhibits a non-circular shape factor, defined by a "racetrack" shape of the composite curve of the conductive material of the first conductive layer 810. Advantageously, such a non-circular shape can improve the performance of one or more ring portions 815, for example by adapting to the geometric and fractional positional constraints imposed by the physical housing and / or the operating frequency limits for maintaining one or more resonant modes in the corresponding gaps 817.

[0105] Figure 8B The power system and switching electronics in a dual-loop configuration of an exemplary resonator 800 are shown. Electrical components include an RF power supply 835 coupled to the exemplary resonator 800 via a switching circuit 840 and a DC power supply 845 coupled to the exemplary resonator via a bias T-shaped element 850. The exemplary resonator 800 is configured to excite and sustain a discharge in a discharge volume between a substrate 805 and a source electrode 855, from which an extraction electrode 860 can extract charged particles, as detailed in more detail below. Figures 2A-3B As shown.

[0106] like Figures 6A-7C Specifically, the switching circuit 840 can be configured to direct an RF power signal to an exemplary resonator 800, switching between a first input point 825-1 and a second input point 825-2, at least in part based on the presence or absence of discharge in the discharge volume. Figure 11 As shown. To this end, each corresponding ring 815 can be configured to perform functions, such as inducing discharge in the absence of discharge, maintaining discharge in the presence of discharge, etc., while maintaining good matching conditions with respect to the impedance and reflected power of the discharge circuit, at least in part based on different fractional positions defined for each ring 815. Conversely, the bias T-shaped element 850 can be configured to modulate the voltage offset of the RF power signal as a method of controlling and / or increasing the operating range of the charged particle flux extracted by the extraction electrode 860.

[0107] Figures 9A-9D This is a schematic diagram illustrating an exemplary resonator 900 component according to some embodiments of the present disclosure, representing... Figures 2A-4CThe ion source embodiment includes a single open-loop resonator and multiple input points 920. The discussion of the exemplary resonator 900 components focuses on the patterning of the resonator 900 elements and the electrical subsystem electrically coupled to them. For this purpose, in Figures 9A-9D One or more components of an exemplary ion source are omitted from the text; these components will be referred to... Figure 2A-4C For a more detailed discussion, an exemplary resonator 900 includes a substrate 905. The substrate 905 defines a first side 907 and a second side 909. The exemplary resonator 900 includes a first conductive layer 910 disposed on the first side 907. The first conductive layer 910 is configured according to a pattern including a ring portion 915. The pattern defines a plurality of input points 920, including a first input point 920-1 and a second input point 920-2. The pattern also defines a gap 925 in the ring portion 915 of the first conductive layer 910. The second side 909 has two fundamental planes opposite the first side 907 relative to the substrate 905. The exemplary resonator 900 includes a second conductive layer 930 disposed on the second side 909.

[0108] Advantageously, by combining the functions of multiple rings 915 into a single ring 915, Figures 9A-9D The multi-input resonator shown can benefit from improved discharge stability and reduced geometry. As with other embodiments of this disclosure, the ring 915 can be circular or non-circular, at least in part based on the space constraints of the charged particle source system into which the exemplary resonator 900 is to be integrated. For this purpose, Figure 5A-8B The discussion regarding fractional positions provided applies to the positions of input points 920 relative to the gap 925 on the ring 915. For example, a first input point 920-1 may be formed at a first fractional position α on the ring 915. A second input point 920-2 may be formed at a second fractional position β on the ring 915. A third input point 920-3 may be formed at a third fractional position γ on the ring 915. In some embodiments, β is greater than α. In some embodiments, γ is greater than both β and α.

[0109] In this configuration, different fractional positions allow the exemplary resonator 900 to operate in different operating modes, such as pre-excitation in the absence of discharge, post-excitation in the presence of discharge, and adaptation to different discharge mixtures that can exhibit differentiated electronic characteristics, involving different RF power signals and different input point 920 positions on the ring. Furthermore, through the fractional position of each corresponding input point 920, the exemplary resonator 900 can be configured to provide well-matched impedance conditions for each operating mode. In some cases, each mode may be associated with a different RF power signal.

[0110] like Figure 5A-8BSpecifically, the exemplary resonator 900 can be configured to excite and sustain discharge near the gap 925 (e.g., Figure 5C Discharge 550). For example Figures 2A-3B Specifically, the exemplary resonator 900 can be electrically coupled to one or more power supply systems, such as an RF power supply 965, a DC power supply 960, etc., via one or more electrical couplers 935. For this purpose, the exemplary resonator 900 is illustrated as having an input point 920 coupled to a control circuit 955. The control circuit 955 is configured to adapt and / or modify the operation of the exemplary resonator, at least in part, based on the excitation of the discharge, thereby maintaining good matching conditions and / or substantially uniform brightness of the charged particle beam source. For this purpose, in Figure 9C The control circuit 955, as shown in detail, may include one or more sets of electrical components 975 electrically coupled to a DC power supply 960 and configured to respond at least in part to changes in one or more operating parameters of the exemplary resonator by altering which input point 920 receives the RF power signal generated by the RF power supply 965.

[0111] In an illustrative example of a dual-input resonator 970, which is an exemplary resonator 900, the first input point 920-1 and the second input point 920-2 are coupled to an RF power supply 965 via an electrical component 975 including diodes (such as PIN diodes) and a capacitor, respectively, and to a DC power supply via a component 975 including a resistor-inductor pair. In some embodiments, the electrical component 975 may include two or more diodes coupled to each input point 920 (e.g., for...). Figure 9C (The dual-input configuration uses four PIN diodes). Similarly, each input point can be coupled to the DC power supply 960 via one or more inductors, resistors, or other electrical components 975. The control circuit 955 configured in this way responds to changes in reflected power caused by discharge excitation at or near the gap 925 by redirecting the RF power signal from the first input point 920-1 to the second input point 920-2. For this purpose, the second input point 920-2 (configured to correspond to input point 920 when a discharge is present) is provided with a bias T-shaped element, more detailed as follows: Figures 6A-6C As shown. In the example of the dual-input resonator 970, three DC power supply units 960 are shown, but the system may contain more or fewer power supply units (e.g., a DC power supply for biasing the resistor-inductor pair and applying a voltage offset to the second input point 920-2). For this purpose, the DC power supply 960 may include voltage regulation subcircuits that allow different voltages and / or currents to be output to different components 975 and / or input points 920.

[0112] The exemplary resonator 900 can be integrated into a charged particle beam system (e.g., as a...). Figure 1A portion of the FIB source 110 is oriented relative to the source electrode 980 and the extraction electrode 985. The resonator 900, source electrode 980, and extraction electrode 985 are electrically coupled to the power supply circuit and control circuit, such as... Figure 1-8B As shown. In this way, charged particle beam systems can generate beams of charged particles (e.g., ions) that can be focused onto a sample to produce characteristic data for imaging and / or microanalysis.

[0113] Figure 10A-10D This is a schematic diagram illustrating an exemplary resonator 1000 component according to some embodiments of the present disclosure, representing... Figure 2A-4C One embodiment of the ion source includes a multipole resonant structure. The discussion of the components of the exemplary resonator 1000 focuses on the patterning of the elements of the resonator 1000. For this purpose, in Figure 10A-10D One or more components of an exemplary ion source are omitted from the text; these components will be referred to... Figure 2A-9D For a more detailed discussion. An exemplary resonator 1000 includes a substrate 1005. The substrate 1005 defines a first side 1007 and a second side 1009. The exemplary resonator 1000 includes a first conductive layer 1010 disposed on the first side 1007. The first conductive layer 1010 is configured according to a pattern including a plurality of loops 1015. This pattern defines an input point 920 through which the first conductive layer 1010 is coupled to an electrical coupler 1040. The loops 1015 are coupled to the input point via corresponding input traces 1030 at corresponding annular connection points 1035. The pattern defines a plurality of loops 1015, thereby defining a gap 1025 in a number twice the number of loops 1015. In the exemplary resonator 1000, the first loop 1015-1 and the second loop 1015-2 together define a first gap 1025-1 between the first end 1050-1 and the second end 1050-2 of the first loop 1015-1 (see...). Figure 10B The second gap 1025-2 between the first ring portion 1015-1 and the second ring portion 1015-2, and the third gap 1025-3 between the first end 1055-1 and the second end 1055-2 of the second ring portion 1015-2 (see...) Figure 10B The second side 1009 has two fundamental planes opposite to the substrate 1005 and the first side 1007. An exemplary resonator 1000 includes a second conductive layer 1045 disposed on the second side 1009.

[0114] Unlike the ion sources disclosed herein, which are not bound by specific physical mechanisms or operating principles, the dipole generator structure of a conventional open-loop resonator device can impose a time-varying electric field at the location where ions are extracted (e.g., near the gap in the toroidal structure). The result of applying this time-varying electric field is that energy can be transferred from electrons in the discharge to ions in the discharge, effectively “heating” the ions in the discharge region as part of a partial thermalization process. While this can be considered advantageous in some respects, such as increasing ion flux by increasing the average energy of the ions, the increased ion temperature can also degrade the internal structure of the ion source (e.g., through ion bombardment), increase the flux of neutral atoms and / or molecules into the column (e.g., in a form of “entrainment”), and potentially degrade precursors by promoting plasma dissociation mechanisms.

[0115] Advantageous is that it has the following characteristics: Figure 10A-10D The multipole resonator of the illustrated embodiment can be configured to form a substantially field-free region in at least a portion of the discharge volume by generating discharges between and / or in the plurality of rings 1015 (e.g., near the plurality of gaps 1025). Figures 10A-10B An embodiment of a quadrupole is shown, wherein the first conductive layer 1010 is configured to have four ends 1050-1, 1050-2, 1055-1 and 1055-2. Figure 10C-10D Examples of a hexapole (having three rings 1015 and six gaps 1025) and an octapole (having four rings 1015 and eight gaps 1025) are shown, wherein the first conductive layer 1010 is provided with six ends 1050, 1055, and 1060, and eight ends 1050, 1055, 1060, and 1065, respectively. An exemplary resonator 1000 can be configured to provide substantially equal voltages to opposite ends (e.g., first end 1050-1 and second end 1055-2) of the quadpole structure over multiple phase periods of an AC power signal (e.g., an RF power signal). In this way, the electric field strength at the center location between the ends 1050 and 1055 of the quadpole remains substantially zero in the presence of discharge.

[0116] A plasma generation structure, wherein the electric field strength at one or more locations in the plasma discharge region is substantially zero, generates a non-thermodynamically equilibrium plasma with an average ion temperature significantly lower than the average electron temperature by at least partially restricting energy transfer between ions and electrons and suppressing the acceleration effect of the electric field in the gap on ions in the plasma. Maintaining a relatively low average ion temperature improves FIB source technology and at least partially increases the brightness of the beam extracted from the ion source. In some cases, the reduced ion temperature in the plasma can also narrow the energy distribution width in the ion beam, making the extraction electrodes (e.g., Figure 2A or Figure 2B Extraction electrode 233 Figure 3A or Figure 3B The angular distribution downstream of the extraction electrode 335 narrows, and / or limits contamination of the ion beam by substances from the ion source itself (e.g., contamination caused by degradation of the internal structure of the ion source due to ion irradiation).

[0117] By carefully coordinating the microwave phase and voltage signals between the ends of the high-order multipole, a zero-field point can be generated between the rings 1015 (e.g., using a microwave drive frequency of about 1.0 GHz to about 1.5 GHz, including its fraction, subrange, and interpolation, and a drive power of about 0.1 W to about 10 W, including its fraction, subrange, and interpolation). Such conditions can reduce and / or substantially eliminate lateral heating of ions accelerated by the electric field, leaving momentum transfer with electrons and other particles as the primary heating mechanism. Due to the reduced average temperature of ions in the discharge region, the resonator of this disclosure exhibits improved brightness in FIB sources.

[0118] Figure 11 This is a block flowchart illustrating an exemplary process for extracting an ion beam from a discharge, based on some embodiments of this disclosure. One or more operations constituting the exemplary process 1100 can be performed by a computer system or other programmable logic machine operable with a charged particle microscope (e.g., Figure 1 The charged ion beam system 1100 and / or components of additional systems or subsystems are coupled, including but not limited to characterization systems, power systems, network infrastructure, databases, and / or user interface devices. For this purpose, the operation of the exemplary process 1100 may be stored as machine-executable instructions in one or more machine-readable media.

[0119] One or more operations of the exemplary process 1100 may be repeated, reordered, and / or omitted, for example, as part of extracting an ion beam from a discharge generated using an ion source of the present disclosure. For this purpose, the operations of the exemplary process 1100 are described as being performed by a system, where it should be understood that the operations may include generating and transmitting control signals between a processor or other logic circuit and the electronic or electromechanical components of the charged particle beam system. For clarity, the operations of the exemplary process 1100 are described in the context of electron microscopy. Embodiments of the present disclosure include processes for generating monochromatic ion beams, as well as other charged particle configurations (such as dual-beam systems). One or more operations that may be performed before and / or after the operations of the exemplary process 1100 are omitted from the exemplary process 1100. For example, operations may include within the vacuum chamber of the operating ion source (e.g., Figure 2A The vacuum chamber 235 is evacuated and maintained. Similarly, operation may include one or more control schemes (e.g., feedback, feedforward, etc.), through which the system of this disclosure modulates one or more operating parameters of the ion source.

[0120] In operation 1105, exemplary process 1100 includes generating a microwave power signal. Generating the power signal may include operating an RF power supply (e.g., Figure 3A The RF power supply 345 is shown with reference to the foregoing diagram. For example, the power of the RF power signal can be from about 0.1W to about 30W, including its fraction, subrange, and interpolation. For example, the frequency of the RF power signal can be from about 100MHz to about 5GHz, including its fraction, subrange, and interpolation. At least in part due to the highly coupled nature of the discharge operation, i.e., the highly nonlinear environment created by the interaction of multiple physical and electrical phenomena, preparing predictive and / or analytical control schemes can be very difficult, if not entirely impossible. For this reason, while it can generally be said that higher power can produce a brighter discharge under certain conditions (e.g., a set of operating conditions), the effects of thermalization, plasma density, ionization fraction, etc., can also degrade performance at higher power and may contaminate the beam, as detailed in more detail in... Figure 10A-10D As shown. Similarly, gaps (e.g., Figure 3B The electric field resonance mode in the gap 370) is related to the first conductive layer (e.g., Figure 3B The geometry of the first conductive layer 320 is strongly coupled, thereby limiting the operating frequency to one or more subranges within which resonant modes that can be excited and / or sustained for discharge are generated. In some embodiments, a single RF power signal is generated in the presence and absence of discharge. In some embodiments, multiple RF power signals are used, distinguished by the presence or absence of discharge. For some embodiments, the RF power signals are modulated during one or more operations of the exemplary process 1100, for example, as part of a control scheme configured to maintain a substantially constant brightness of the ion source while maintaining good matching conditions in the ion source in the presence and / or absence of discharge.

[0121] In operation 1110, exemplary process 1100 includes using an excitation input point (e.g., Figure 7A First input point 735-1 Figure 8A First input point 825-1 Figure 9A The first input point 920-1) is used to excite discharge. Embodiments of this disclosure include multi-ring, multi-point, and multi-pole resonators, which may include multiple input points at different locations in the first conductive layer. The determination is based at least in part on the excitation input point (e.g., for RF power signals in the absence of discharge) and the maintenance input point (e.g., for RF power signals in the presence of discharge), such as... Figure 5A-10D Specifically, the control and / or switching circuitry (e.g., Figure 7C 755 switching circuit Figure 8B Switching circuit 840 Figure 9CThe control circuit 955, etc., can be configured to direct the RF power signal generated in operation 1105 to the excitation input point until excitation is detected, for example, more detailed cases such as Figure 9C As shown.

[0122] In operation 1115, exemplary process 1100 includes using a sustained input point (e.g., Figure 7A The second input point 735-2 Figure 8A Second input point 825-2 Figure 9A The second input point 920-2) is used to maintain the discharge. Embodiments of this disclosure include control circuitry configured to respond to the discharge excitation of operation 1110 by redirecting the RF power signal generated in operation 1105 to the maintenance input point. To reduce the risk of damage caused by poorly matched discharge conditions, which depends at least in part on the reflected power, the response time of the control circuitry can be improved by using power circuitry that includes hardwired components, such as... Figure 9C As shown. In some embodiments, one or more additional or alternative control schemes are implemented using the measured parameters of the ion source of this disclosure, along with simultaneous and / or subsequent calculations. In an example, the extraction electrode (e.g., Figures 3A-3B The brightness measurement downstream of the extraction electrode 335 can be used to modulate the DC offset voltage and / or RF power, but can also be used to identify when a discharge is present. In this way, the measurement and calculation can be compared with a reference... Figure 9C The aforementioned circuit element-based technology may be used in conjunction with or in place of this technology.

[0123] In operation 1120, exemplary process 1100 includes extracting a beam of charged particles. In some embodiments, extracting the beam of charged particles may include energizing an extraction electrode to pass through a hole in a source electrode that serves as an ion source assembly (e.g., Figure 2B Hole 265, Figure 3A -B's aperture 331) draws out charged particles from the discharge region (e.g., by electrostatic attraction). These principles will be referred to... Figures 2A-3B A more detailed discussion is needed. Energizing the extraction electrode can include applying a DC voltage to the electrode, such as... Figure 5C-9D As shown, but may also include applying an alternating or intermittent voltage to the extraction electrode (e.g., as part of a pulsed scheme).

[0124] In operation 1125, exemplary process 1100 includes applying an offset voltage to the RF power signal. A bias T-shaped element (e.g., ...) can be used. Figures 6A-6C The bias T-shaped element 640 is used to apply the offset voltage, more details are as follows Figures 6A-6CAs shown in 8A-8B and 9C. The offset voltage provides another control parameter by which the brightness of the ion source of this disclosure can be modulated, with little or no effect on the matching conditions of the discharge circuit. Embodiments of this disclosure include an offset voltage applied to a power signal applied as part of operations 1110 and 1115 (e.g., in the presence and absence of discharge). For this purpose, the offset voltage can be used to assist in the excitation discharge and / or, as an alternative, to modulate the discharge after excitation.

[0125] Various embodiments have been described above. Specific configurations and details have been set forth for illustrative purposes to provide a thorough understanding of the embodiments. However, it will be apparent to those skilled in the art that these embodiments may be practiced without these specific details. Furthermore, well-known features may have been omitted or simplified to avoid obscuring the described embodiments. While the exemplary embodiments described herein focus on charged particle beam systems, particularly dual-beam FIB systems, these are intended as non-limiting illustrative examples. Embodiments of this disclosure are directed to analytical instrument systems in which a wide array of material samples can be analyzed to determine chemical, biological, physical, structural, or other properties, as well as other aspects, including but not limited to chemical structure, trace elemental composition, etc. Furthermore, embodiments of this disclosure can be applied to manual processes or operations configured for automated (e.g., performing one or more processes or operations without human intervention), pseudo-automated (e.g., performing one or more processes or operations with limited human intervention and / or human initiation), and / or sample preparation (e.g., thin-layer preparation) workflows, such as those used in semiconductor sample metrology.

[0126] Some embodiments of this disclosure include a system having one or more data processors and / or logic circuits. In some embodiments, the system includes a non-transitory computer-readable storage medium storing instructions that, when executed on the one or more data processors and / or logic circuits, cause the one or more data processors and / or logic circuits to perform part or all of the one or more methods disclosed herein and / or part or all of one or more processes and workflows. Some embodiments of this disclosure include a computer program product tangibly embodied in a non-transitory machine-readable storage medium, the computer program product including instructions configured to cause one or more data processors and / or logic circuits to perform part or all of the one or more methods disclosed herein and / or part or all of one or more processes.

[0127] The terminology and expressions used herein are descriptive and not restrictive only. Their use is not intended to exclude any equivalents of the shown and described features or portions thereof, but rather to facilitate the understanding that various modifications may be made within the scope of the claims. Therefore, it should be understood that while this disclosure includes specific embodiments and optional features, modifications and alterations to the concepts disclosed herein can be made by those skilled in the art, and such modifications and alterations are considered to be within the scope of the appended claims.

[0128] When a term is used without a clear definition, it should be understood that unless the term has a special and / or specific meaning in the field of charged particle microscopy systems or other related fields, the term refers to its general meaning. The terms “about” or “substantially” are used to indicate a deviation from the stated property, where the deviation has little or no effect on the corresponding function, property, or attribute of the described structure. In the example shown where a dimensional parameter is described as “substantially equal” to another dimensional parameter, the term “substantially” is intended to reflect that the two parameters being compared may be unequal within permissible limits (such as confidence intervals inherent in manufacturing tolerances or system operation). Similarly, where geometric parameters (such as alignment or angular orientation) are described as “about” perpendicular, “substantially” perpendicular, or “substantially” parallel, the terms “about” or “substantially” are intended to reflect that the alignment or angular orientation may differ from the precisely stated condition (e.g., not precisely perpendicular) within permissible limits. For numerical values ​​(such as diameter, length, width, etc.), the term “about” can be understood to describe a deviation of up to ±10% from the stated value. For example, the size "about 10mm" can describe sizes ranging from 9mm to 11mm.

[0129] This specification provides exemplary embodiments and is not intended to limit the scope, applicability, or configuration of this disclosure. Rather, the following description of exemplary embodiments will provide guidance to those skilled in the art for implementing various embodiments. It should be understood that various changes may be made to the function and arrangement of elements without departing from the spirit and scope set forth in the appended claims. Specific details are given in the description to provide a thorough understanding of the embodiments. However, it should be understood that embodiments may be practiced without these specific details. For example, particular system components, systems, processes, and other elements of this disclosure may be shown schematically or omitted from the illustrations to avoid obscuring the embodiments with unnecessary details. In other instances, well-known circuits, processes, components, structures, and / or techniques may be shown without unnecessary details.

Claims

1. A charged particle source, comprising: Resonators, including: A dielectric substrate defining a first side and a second side, with the second side opposite to the first side; A first conductive layer is disposed on a first side, the first conductive layer being configured according to a pattern including a ring portion, the ring portion defining a gap in the first conductive layer; and A second conductive layer disposed on the second side; and The source electrode is positioned adjacent to the first side, the source electrode defines a hole, and the source electrode is offset from the dielectric substrate.

2. The charged particle source according to claim 1, further comprising: The radio frequency (RF) power supply is operatively coupled to the resonator and calibrated to match the impedance of the RF power signal in the event of a discharge between the loop and the source electrode.

3. The charged particle source of claim 1, wherein the ring portion is a first ring portion, the gap therein is a first gap, and wherein the pattern further includes a second ring portion defining a second gap, the system further comprising: An RF power supply is operatively coupled to a resonator via a first ring or a second ring, wherein: The RF power supply is configured to provide a first well-matched impedance condition for the first RF power signal in the event of a discharge in the first gap; The RF power supply is configured to provide a second well-matched impedance condition for the second RF power signal in the absence of discharge in the second gap; and The first gap and the second gap are close to each other.

4. The charged particle source of claim 3, wherein the ring portion defines a tapering portion that narrows toward the corresponding first gap or second gap.

5. The charged particle source of claim 3, wherein the RF power supply is coupled to the resonator via a switching circuit configured to couple a first ring portion to the RF power supply in the presence of a discharge and a second ring portion to the RF power supply in the absence of a discharge.

6. The charged particle source according to claim 3, wherein: The first ring defines the first power injection point; The second ring defines the second power injection point; The first gap is defined at a first fractional position α in the first ring relative to the first power injection point; and The second gap is defined at a fractional position β in the second ring relative to the second power injection point. Wherein, for a given input point in the ring, the fractional position is the ratio of the length of the first path between the gap and the given input point along the first direction to the length of the second path between the gap and the given input point in a second direction different from the first direction.

7. The charged particle source according to claim 6, wherein the first fractional position α and the second fractional position β are substantially equal.

8. The charged particle source according to claim 1 further includes a DC bias T-shaped element electrically coupled to the first ring portion, the DC bias T-shaped element including a DC power input and an RF power input, the included components configuring the DC bias T-shaped element to apply a DC bias to the RF power signal, thereby modifying the offset voltage of the RF power signal.

9. The charged particle source of claim 1, wherein the source electrode is electrically coupled to a reference voltage shared with the second conductive layer.

10. The charged particle source of claim 1, operatively coupled to a focused ion beam (FIB) column, the FIB column including an extraction electrode, wherein the resonator is oriented relative to the extraction electrode such that the source electrode is located between the first side and the extraction electrode.

11. The charged particle source according to claim 10, further comprising a source device, the source device comprising: Source electrode; Fluid transport coupler; Fluid removal coupler; and Electrical coupler, The resonator is located within the source device and is operatively coupled to the electrical coupler.

12. The charged particle source according to claim 11, further comprising: Vacuum enclosure; An isolation bracket, housed within a vacuum enclosure, is mechanically coupled to the vacuum chamber and the source device, and together defines the source chamber and the FIB chamber. The isolation bracket comprises an electrically insulating material that is electrically insulating at the reference voltage of the charged particle source system. The source chamber is fluidly coupled to the FIB chamber via a bypass conduit.

13. A charged particle beam system, the system comprising: The source portion includes: Resonators, including: A dielectric substrate defining a first side and a second side, with the second side opposite to the first side; A first conductive layer is disposed on a first side, the first conductive layer being configured according to a pattern including a ring portion, the ring portion defining a gap in the first conductive layer; and A second conductive layer disposed on the second side; and The source electrode is configured to be adjacent to the first side, the source electrode defines a hole adjacent to the first end of the ring, and the source electrode is offset from the first conductive layer; A focused ion beam (FIB) column, operatively coupled to an ion source portion, and comprising multiple charged particle optics; and The vacuum chamber is operatively coupled to the FIB column.

14. The system of claim 13, wherein the source electrode comprises a foil coupled to a support, and the aperture is formed in the foil.

15. The system of claim 14, wherein the hole is characterized by a diameter of about 20 μm to about 200 μm and an aspect ratio of about 0.05 to about 0.

5.

16. The system of claim 13, wherein the gap is defined between a first end and a second end of the ring, and wherein the hole is substantially centered on the first end of the ring.

17. The system of claim 13, wherein the source portion further comprises a source device, the source device comprising: Dielectric substrate; as well as A housing coupled to a dielectric substrate, the housing comprising: Source electrode; Fluid transport coupler; Fluid removal coupler; and An electrical coupler is operatively coupled to a first conductive layer and a second conductive layer via a housing.

18. The system of claim 17, wherein at least a portion of the housing is coupled to a voltage source configured to apply a voltage of about 1 kV to about 350 kV to that portion of the housing.

19. The system of claim 13, wherein the FIB column includes an extraction electrode, wherein the source portion is oriented relative to the extraction electrode such that the source electrode is located between the first side and the extraction electrode.

20. The system according to claim 13, wherein: This ring is the first ring; The pattern defines a resonant multipole structure including the first ring. The resonant multipole structure includes a second ring; and The first and second rings define four gaps between the four ends.

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