Ion beam energy and charge quantity distribution measuring method and device

Abstract

The invention discloses an ion beam energy and charge quantity distribution measurement method and device, and belongs to the technical field of plasma diagnosis. Applying negative bias voltage to the inlet grid to screen ions; applying scanning voltage to the deceleration grid to screen ions with different energies; scattering ions are filtered at the filtering grid electrode; negative bias voltage is applied to the suppression grid to suppress escape of secondary electrons; ion current is measured through a collector, weak ion current signals are acquired through a scanning generation and acquisition control circuit, the ion current signals are converted into modulation scanning high-voltage signals, and synchronous measurement is carried out on a plurality of measurement front ends through an FPGA-based synchronous acquisition circuit at a measurement rear end; the wireless charging module supplies power to the measurement front end, and the wireless communication module transmits measurement data to the measurement rear end. According to the method, key data required by process development and quality control are provided, and system engineers are helped to understand real behaviors of the plasma process.

Description

Technical Field

[0001] This application belongs to the technical field of plasma diagnostics, specifically relating to a method and apparatus for measuring ion beam energy and charge distribution. Background Technology

[0002] Devices for measuring ion energy distribution (IED) and charge in plasma processing systems are used in industrial applications such as semiconductor manufacturing and solar panel production. The core function of these devices is to measure the ion energy distribution reaching the substrate surface during plasma processing, which is crucial for controlling key process parameters such as etching rate, selectivity, and anisotropy. Measuring the ion energy distribution function (IEDF) in plasma has wide applications in semiconductor manufacturing, plasma research, and industrial film deposition. The ion energy distribution determines the etching rate, anisotropy, and selectivity, and also affects the density and stress characteristics of thin film deposition.

[0003] Measuring the energy and charge distribution of the ion beam is one of the core tasks of plasma diagnostics. Common ion beam measurement methods in existing technologies include: Rutherford backscattering analysis (RBS): By measuring the elastic scattering events between high-energy ions and target atomic nuclei, the energy and elemental composition of ions can be inferred.

[0004] Particle-excited X-ray fluorescence (PIXE): This method uses charged particles to excite samples and emit characteristic X-rays to analyze the types and amounts of elements.

[0005] While the aforementioned technologies have been widely applied in specific fields, they generally suffer from the following technical shortcomings: Existing devices typically rely on external cables for power supply and data transmission. The presence of cables in a vacuum environment can easily introduce electromagnetic interference and increase system complexity. The data acquisition module is separated from the measurement front end, which makes it impossible to achieve real-time signal processing and dynamic range adjustment, thus limiting the sensitivity to weak ion currents. Summary of the Invention

[0006] To address the shortcomings of existing technologies mentioned above, a method and apparatus for measuring ion beam energy and charge distribution are provided. This apparatus directly measures ion bombardment characteristics from the substrate location, rather than inferring them indirectly. This measurement method provides key data required for process development and quality control, helping system engineers understand the true behavior of plasma processes.

[0007] The technical solution is as follows: On the one hand, a method for measuring ion beam energy and charge distribution is provided, comprising the following steps: By grounding the inlet gate or applying a negative bias voltage, ions are screened to enter the measurement front end and the incident angle of the ion beam is controlled. A scanning voltage is applied to the deceleration gate to filter ions whose kinetic energy is higher than the scanning voltage potential; Scattered ions are filtered through the filter gate; Applying a negative bias voltage to the gate suppresses the escape of secondary electrons; The ion current is measured by collecting electrodes. The weak ion current signal is collected by the scanning generation and acquisition control circuit. The ion current signal is converted into a modulated scanning high voltage signal. The FPGA-based synchronous signal receiving unit at the measurement back end controls multiple probes to perform synchronous measurements on multiple measurement front ends. The measurement front end is powered by a wireless charging module, and the measurement data is transmitted to the measurement back end via a wireless communication module. The measurement front end includes an inlet gate, a deceleration gate, a filter gate, a suppression gate, a collection gate, a scan generation and acquisition control circuit, and a wireless charging module. The software analysis module at the measurement backend displays the ion energy distribution function and radial ion flux distribution in real time.

[0008] Preferably, the wireless communication module uses infrared or Bluetooth communication.

[0009] Preferably, the wireless charging module includes a transmitting coil, a receiving coil, and a measurement front-end circuit. The input terminal of the transmitting coil is connected to the output terminal of the DC-AC high-frequency inverter circuit, and the output terminal is connected to the input terminal of the receiving coil. The output terminal of the receiving coil is connected to the input terminal of the AC-DC rectifier and filter circuit, and the output terminal of the AC-DC rectifier and filter circuit is connected to the measurement front-end circuit. The input terminal of the DC-AC high-frequency inverter circuit is connected to the AC / DC module and the chamber power supply module.

[0010] Preferably, the scanning generation and acquisition control circuit acquires a weak ion current signal, and the calculation process is as follows: in, k Modulation depth; This is a phase delay, which is related to the plasma energy distribution; , This indicates the output current signal; Indicates the amplitude of the output signal. The reference signal for demodulation measurement; X、 It is an in-phase signal; Y、 Orthogonal signals; R The amplitude of the output signal; The phase angle of the output signal; The sine value of the reference signal, The cosine value of the reference signal.

[0011] On the other hand, an ion beam energy and charge distribution measurement device is provided, comprising: The measurement front end, integrated in a wafer-shaped substrate, includes: Shielding shell, The multi-layer gate structure disposed within the housing includes, in sequence along the ion incident direction, an inlet gate, a deceleration gate, a filter gate, a suppression gate, and a collector, with each gate separated by an insulating layer. A scanning generation and acquisition control circuit employing phase-locked modulation technology has its output terminal connected to the deceleration gate. The wireless communication module is used to transmit the acquired signal data to the measurement backend; A wireless charging module is used to provide power to the measurement front end; The measurement backend, wirelessly connected to the measurement frontend via a wireless communication module, includes: The FPGA-based synchronous signal receiving unit is used to receive data transmitted by the wireless communication module and simultaneously measure multiple measurement front-ends through multiple probes. The software analysis module is used to display the ion energy distribution function, average energy, and ion flux in real time.

[0012] Preferably, at least one insulating layer includes a peripheral portion with a reduced thickness relative to the remainder of the insulating layer.

[0013] Preferably, the outer portion of the insulating layer is in the shape of a convex or concave arc.

[0014] Preferably, the filter gate is a curved grid structure, which is a curved surface formed by rotating about a parabolic axis of symmetry.

[0015] Preferably, the scanning generation and acquisition control circuit includes a transimpedance amplifier I / V conversion module, a low-pass filter, a lock-in amplifier, a controller, and an acquisition circuit. The input terminal of the lock-in amplifier is connected to the low-pass filter and the reference modulation signal, respectively. The output terminal of the lock-in amplifier is connected to the input terminal of the acquisition circuit. The output terminal of the acquisition circuit is connected to the input terminal of the controller. The output terminal of the controller is connected to the reference modulation signal and the high-precision voltage source. The ion current signal passes sequentially through the transimpedance amplifier I / V conversion module, the low-pass filter, the lock-in amplifier, the acquisition circuit, the controller, the reference modulation signal, and the high-precision voltage source, and outputs a modulated scanning high-voltage signal.

[0016] Preferably, the FPGA-based synchronous acquisition circuit generates a synchronous trigger signal, which is sent to the collector of the measurement front end through a wireless communication module, so as to realize synchronous measurement by multiple measurement front ends.

[0017] The technical solution includes at least the following technical effects: 1. Energy resolution on the order of 0.1 eV is achieved through the coordinated operation of a multi-layer gate structure (entry gate, deceleration gate, filter gate, suppression gate, and collector).

[0018] 2. Combining phase-locked modulation (PLM) technology and FPGA digital mixing algorithm enhances the detection sensitivity of weak ion currents.

[0019] 3. Programmable logic devices (FPGAs) are used to implement digital mixing, filtering, and computation, avoiding the temperature drift problem of analog circuits. High-precision characterization of ion flux spatial distribution is achieved through distributed multi-probe layout and time-domain synchronous triggering.

[0020] 4. Through highly integrated wireless design and optimized wireless communication and wireless charging modules, the measurement front end is made into a wafer-like structure that can be directly embedded into the substrate stage, completely eliminating the interference of physical cables, realizing true in-situ measurement, and ensuring reliability and flexibility in strong electromagnetic interference environments.

[0021] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0022] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0023] Figure 1 A flowchart of a method for measuring ion beam energy and charge distribution provided in a preferred embodiment of this application; Figure 2A schematic diagram of a multi-gate structure of an ion beam energy and charge distribution measurement device provided in a preferred embodiment of this application; Figure 3 This is a schematic diagram of the entrance gate structure; Figure 4(a) is a diagram of the curved grid structure of the filter gate provided in a preferred embodiment of this application; Figure 4(b) is a curved grid structure diagram of the filter gate from another perspective in Figure 4(a); Figure 5(a) shows the structure of the insulating layer with a convex arc shape on the outer part; Figure 5(b) shows the structure of the insulating layer with a concave arc shape in the outer part; Figure 6(a) is a schematic diagram of the particle flight trajectory under a 950V suppression gate voltage; Figure 6(b) is a schematic diagram of the particle flight trajectory under a 1050V suppression gate voltage; Figure 7 This is a schematic diagram of a scan generation and acquisition control circuit provided in a preferred embodiment of this application; Figure 8 This is a schematic diagram of the working waveform of an ion beam energy and charge distribution measurement method provided in a preferred embodiment of this application; Figure 8 (a) represents the input ion signal under strong noise conditions. Red represents the ideal original signal, and blue represents the actual detected signal with noise. Figure 8 (b) indicates the processing flow of the in-phase component I-channel signal. Purple represents the DC signal after low-pass filtering, and light blue represents the result of multiplying the unfiltered measured signal and the reference signal. Figure 8 (c) indicates the quadrature component Q-path signal processing flow. Purple represents the DC signal after low-pass filtering, and light blue represents the result of multiplying the unfiltered measured signal and the reference signal. Figure 8 (d) represents the output result, the extracted signal amplitude; Figure 9 This is a schematic diagram of a preferred embodiment of the FPGA controller controlling multiple probes to perform synchronous measurements on multiple measurement front ends, as shown in the diagram. Figure 10 This is a schematic diagram of an electromagnetic wireless charging module provided in a preferred embodiment of this application; Figure 11(a) is a schematic diagram of the ion energy distribution results displayed in real time by the software analysis module provided in a preferred embodiment of this application; Figure 11(b) is a schematic diagram of the charge distribution results displayed in real time by the software analysis module provided in a preferred embodiment of this application; Explanation of reference numerals in the attached figures: 10. Inlet gate; 20. Deceleration gate; 30. Filter gate; 40. Suppression gate; 50. Collector; 60. Insulating layer; 70. Shielding shell; 80. Rotation axis; 90. Parabola. Detailed Implementation

[0024] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0025] This invention provides an ion beam energy and charge distribution measurement device, which is applied in plasma processing systems. It directly measures ion bombardment characteristics from the substrate location, rather than inferring them indirectly. This measurement method provides key data required for process development and quality control, helping system engineers understand the true behavior of plasma processes.

[0026] This measuring device has a wide range of applications in scientific research, mainly including: basic plasma physics research, studying the ion acceleration mechanism and energy distribution characteristics under different discharge conditions; plasma-surface interaction research, analyzing the relationship between ion energy and surface modification effect; characterization of novel plasma sources: evaluating the performance of novel sources such as pulsed plasma and magnetized plasma; and plasma model verification: providing experimental verification data for computer simulation.

[0027] This invention provides an ion beam energy and charge distribution measurement device. The placement of the device is optimized based on the measurement target (such as ion energy distribution and substrate surface flux) and the plasma cavity structure, primarily considering the simulation of the actual ion bombardment environment of the substrate. In one embodiment, the measurement front end is placed directly on the substrate stage, replacing the substrate to be processed, to measure the actual ion energy distribution and ion flux on the substrate surface.

[0028] Example 1 As attached Figure 1 As shown, the present invention provides a method for measuring ion beam energy and charge distribution, comprising the following: By grounding the inlet gate or applying a negative bias voltage, ions are screened to enter the measurement front end and the incident angle of the ion beam is controlled. Specifically, by grounding the inlet gate or applying a negative bias voltage (typically -10 V to -50 V), the potential difference is used to repel electrons, allowing only positive ions to pass through and enter the measurement front end. At the same time, external electric field interference is shielded to achieve electron blocking and control the incident angle of the ion beam, reducing ion trajectory divergence and improving the analysis accuracy of subsequent grids.

[0029] A scanning voltage is applied to a decelerating gate to filter ions with kinetic energy higher than the scanning voltage potential. Specifically, an adjustable bias voltage is applied to the decelerating gate to filter ions of different energies. Optionally, an adjustable scanning voltage of 0~1500V is applied to form a decelerating electric field, allowing only ions with kinetic energy higher than this potential to pass through, thus achieving energy-based grading. The voltage scanning step is ≤0.1V (as high as possible), and combined with phase-locked loop technology to detect weak currents (fA~pA level), the energy resolution can reach the order of 0.1eV.

[0030] Scattered ions are filtered at the filter gate. Specifically, the filter gate filters scattered ions and intercepts ions that change direction due to collisions, ensuring that only ions moving along the axis enter the collector. In one embodiment, a copper mesh shielding layer is added in high-RF environments (such as inductively coupled plasma, ICP) to block IEDF broadening caused by RF coupling.

[0031] Applying a negative bias voltage to the suppression gate suppresses the escape of secondary electrons; applying a negative bias voltage of -5 V to -20 V to the suppression gate prevents the escape of secondary electrons generated by ion collisions with the collector, thus avoiding distortion of the current signal.

[0032] The ion current is measured by the collecting electrode. The weak ion current signal is acquired by the scanning generation and acquisition control circuit. The ion current signal is converted into a modulated scanning high voltage signal. The FPGA-based synchronous acquisition circuit at the measurement back end controls multiple probes to perform synchronous measurements on multiple measurement front ends. Specifically, the collecting electrode measurement achieves time resolution by suppressing the ion current of the gate and through the FPGA-based synchronous acquisition circuit.

[0033] A scanning generation and acquisition control circuit based on phase-locked modulation technology was adopted to realize the measurement function of weak signals and improve the detection accuracy. A high-frequency sinusoidal voltage was applied to the deceleration grid of the measuring device. The following expression: In the formula, To scan the DC bias voltage, For modulation amplitude, To modulate the carrier frequency, This serves as the reference signal for demodulation measurements. As ions pass through the decelerating gate, their energy is modulated to a corresponding frequency. (Typical frequencies can be hundreds of kHz to MHz, as long as the frequency meets the requirements for interference signal suppression. In engineering practice, the feasibility of the circuit needs to be considered.) The slowly changing ion current (which can be approximated as a DC signal) is converted into an AC signal, avoiding interference caused by low frequencies and RF interference from the base station.

[0034] The ion current is affected by the modulation voltage, and the output signal is: In the formula, k Modulation depth; This is a phase delay, which is related to the plasma energy distribution; , This represents the output current signal. This represents the amplitude of the output signal. Separation is achieved by utilizing the differences in frequency and phase between the signal and noise; the reference signal for demodulation measurement is... By multiplying the measured signal and the quadrature reference signal in the digital domain, and then extracting the DC component through a low-pass filter, the desired clean measurement signal is obtained. X, Y ), where the reference signal It is implemented by an FPGA controller.

[0035] in, X、 It is an in-phase signal (in-phase component); Y、 These are orthogonal signals (orthogonal components); R The amplitude of the output signal; The phase angle of the output signal. The sine value of the reference signal, The cosine value of the reference signal.

[0036] Digital mixing, filtering, and computation are implemented using programmable logic devices (FPGAs) to avoid the temperature drift problem of analog circuits.

[0037] Phase-locked modulation is equivalent to a high-Q bandpass filter, allowing only the bandwidth to pass through. Extremely narrow signal. Noise power is compressed to... Internally, the signal-to-noise ratio is improved by a factor of several. A low-pass filter is connected after the phase-locked output, with the cutoff frequency set to more than twice the ion energy scan rate to preserve the complete harmonic components of the ion energy distribution.

[0038] By combining phase-locked modulation (PLM) technology and FPGA digital mixing algorithm, the detection sensitivity of weak ion currents is enhanced. In environments with high-frequency plasma noise (such as RF noise), weak signals at the μV level can be extracted, and the energy resolution can be improved to the order of 0.1 eV.

[0039] The measurement front end is powered by a wireless charging module, and the measurement data is transmitted to the measurement back end via a wireless communication module. The measurement front end includes an inlet gate, a deceleration gate, a filter gate, a suppression gate, a collection gate, a scan generation and acquisition control circuit, and a wireless charging module.

[0040] like Figure 8 The aforementioned method, based on an FPGA-based synchronous acquisition circuit, employs a multi-probe distributed layout and synchronization technology to achieve time-domain measurement, reflecting the temporal changes in ion beam current. Due to its large dynamic range for ion flux measurement and support for multi-probe configuration, it can analyze the ion flow uniformity of large-area substrates. The configuration of multiple collector electrodes, driven by FPGA and other control circuits, enables synchronous measurement, achieving uniformity and distribution testing, and realizing spatial distribution measurement.

[0041] The wireless charging module and wireless communication module used in this invention employ wireless communication and wireless charging methods, avoiding the installation difficulties caused by connecting the probe and external power supply and measuring equipment through cables in the prior art. This achieves advantages such as anti-interference, flexible installation, real-time detection, and reduced maintenance trouble for the ion beam energy and charge distribution measuring device.

[0042] The software analysis module at the measurement backend displays the ion energy distribution function and radial ion flux distribution in real time. Specifically, the system's supporting professional software can display parameters such as the ion energy distribution function (IEDF), average energy, and ion flux in real time, and supports data recording and trend analysis, facilitating process monitoring and fault diagnosis. The collected data can be used to generate ion energy distribution and ion charge distribution (concentration) graphs, as shown in Figure 11(a) and Figure 11(b).

[0043] Example 2 An ion beam energy and charge distribution measurement device is provided, including a measurement front end and a measurement back end.

[0044] The measurement front end integrates a multi-layer gate structure, scan generation and acquisition control circuit, wireless communication module, wireless charging module, etc., into a wafer-shaped substrate.

[0045] The measurement front end includes: Shielding shell, The multi-layer gate structure disposed within the housing includes, in sequence along the ion incident direction, an inlet gate, a deceleration gate, a filter gate, a suppression gate, and a collector, with each gate separated by an insulating layer; The output terminal of the scanning generation and acquisition control circuit based on phase-locked modulation technology is connected to the deceleration gate. The wireless communication module is used to transmit the acquired signal data to the measurement backend; A wireless charging module is used to provide power to the measurement front end; The measurement backend, wirelessly connected to the measurement frontend via a wireless communication module, includes: The FPGA-based synchronous acquisition circuit control is used to receive data transmitted from the wireless communication module and simultaneously measure multiple measurement front-ends through multiple probes. The software analysis module is used to display the ion energy distribution function, average energy, and ion flux in real time.

[0046] In the design of the insulating layer 60, at least one insulating layer includes a peripheral portion with a reduced thickness relative to the remaining portion of the insulating layer to improve the withstand voltage capability; as shown in Figures 5(a) and 5(b), the peripheral portion of the insulating layer is convex or concave.

[0047] like Figure 2 As shown, the measurement front end adopts a multi-layer grid structure, including an inlet grid 10, a deceleration grid 20, a filter grid 30, a suppression grid 40, and a collector 50. Each grid is separated by an insulating layer 60. Ion energy screening is achieved by applying different potentials. Each grid layer performs a specific function, screening ions of different energies and suppressing interference through synergistic action. Plasma density directly affects the grid size, mainly involving the balance between ion flux limitation, electric field uniformity, and measurement accuracy.

[0048] Among them, such as Figure 3 As shown, the inlet gate 10 typically has an aperture of 0.1~0.5 mm; for high-density plasmas, it is typically >10 mm. 10 cm - ³, Choose a large aperture, typically 0.3~0.5 mm, to avoid ion accumulation, the formation of space charge effect, and distortion of the decelerating electric field distribution; for low-density plasmas, typically <10 10 For a smaller aperture of 0.1~0.3mm, cm⁻³ is selected to achieve higher energy resolution. Corrosion-resistant metals, such as molybdenum and nickel alloys, are chosen as the materials.

[0049] The filter gate 20 employs a curved grid structure. In one embodiment, as shown in Figures 4(a) and 4(b), the curved grid structure is formed by rotating about the axis of rotation 80 of the parabola 90 to enhance ion focusing capability. A copper mesh shielding layer is added in high-RF environments (such as Inductively Coupled Plasma, ICP) to block IEDF broadening caused by RF coupling. Grounding design suppresses noise, shields against external electromagnetic interference, and improves the signal-to-noise ratio.

[0050] For a deceleration gate of 30, the gate spacing must satisfy d being much greater than λ. De(Debye length), high-density plasma (λ) De When the diameter is <0.1 mm, d ≥ 1 mm must be ensured to avoid electric field distortion. The output of the scanning generation and acquisition control circuit is connected to the deceleration gate. The deceleration gate is controlled by a precise time synchronization circuit based on FPGA at the measurement backend, which achieves strict synchronization of voltage control and ensures voltage consistency (deviation <0.1%).

[0051] Based on the embedded high-voltage generator design, adjustable high voltage is generated within a limited space, and ion energy in the range of 0-1500 eV can be measured. Figure 6 shows the comparison of the throughput of 1000 V ions by the high-voltage generator near 1000 V, and the difference in ion throughput under 950 V and 1050 V high voltages. Figure 6(a) is a schematic diagram of the particle flight trajectory under the 950 V suppression gate voltage; Figure 6(b) is a schematic diagram of the particle flight trajectory under the 1050 V suppression gate voltage. At 950 V, 99% of the particles can pass through the deceleration gate to reach the receiver, while at 1050 V, 99% of the particles cannot pass through the deceleration gate to reach the receiver.

[0052] like Figure 7 As shown, the scanning generation and acquisition control circuit includes a transimpedance amplifier I / V conversion module, a low-pass filter, a lock-in amplifier, a controller, and an acquisition circuit. The input terminal of the lock-in amplifier is connected to the low-pass filter and the reference modulation signal, respectively. The output terminal of the lock-in amplifier is connected to the input terminal of the acquisition circuit. The output terminal of the acquisition circuit is connected to the input terminal of the controller. The output terminal of the controller is connected to the reference modulation signal and the high-precision voltage source. The ion current signal passes sequentially through the transimpedance amplifier I / V conversion module, the low-pass filter, the lock-in amplifier, the acquisition circuit, the controller, the reference modulation signal, and the high-precision voltage source, and outputs a modulated scanning high-voltage signal.

[0053] like Figure 8 As shown, Figure 8 (a) represents the input ion signal under strong noise conditions. Red represents the ideal original signal, and blue represents the actual detected signal with noise. Figure 8 (b) indicates the processing flow of the in-phase component I-channel signal. Purple represents the DC signal after low-pass filtering, and light blue represents the result of multiplying the unfiltered measured signal and the reference signal. Figure 8 (c) indicates the quadrature component Q-path signal processing flow. Purple represents the DC signal after low-pass filtering, and light blue represents the result of multiplying the unfiltered measured signal and the reference signal. Figure 8 (d) represents the output result, the extracted signal amplitude, and the calculated measurement result of the reduced ion energy distribution.

[0054] like Figure 8 As shown, the analysis process is as follows: The input ion signal to be detected and a reference signal are used. The reference signal is generated by FPGA control. After the input ion signal is multiplied by the reference digital domain, the result can be obtained. Figure 8 (b) Figure 8 (c) shows the I and Q signals. The DC component is extracted by low-pass filtering. The signal amplitude and phase are calculated by the in-phase I and quadrature Q components to obtain accurate ion energy distribution measurement results.

[0055] The gate is suppressed by carbonizing the gate surface to reduce electron emission. A negative bias voltage (-5 V to -20 V) is applied to prevent secondary electrons generated by ion bombardment of the collector from escaping, thus avoiding distortion of the current signal.

[0056] The collector electrode 50 is used to measure the ion current through the suppressed gate, achieving time resolution via an FPGA-based synchronous acquisition circuit. A position-based layout among the multi-channel probes enables regional measurement of the plasma distribution at the base.

[0057] The probe is designed to be miniaturized; the thickness of the probe can be as small as 5 mm, depending on the voltage level.

[0058] Complex power modes such as pulsed plasma and modulated plasma are becoming increasingly common in industrial applications, demanding higher system temporal resolution. For example, pulsed plasmas like HiPIMS operate at microsecond-level pulse velocities. Increasing energy and thus improving temporal resolution places demands on acquisition speed, synchronization control, and processing capabilities.

[0059] Employing a multi-probe distributed layout and synchronization technology, time-domain measurements are achieved, reflecting the temporal changes in ion beam current. The ion flux measurement has a large dynamic range, supports multi-probe configurations, and can analyze the ion flow uniformity of large-area substrates. The configuration of multiple collector electrodes, driven by FPGA and other control circuits, enables synchronous measurements, achieving uniformity and distribution testing, and realizing spatial distribution measurements.

[0060] like Figure 9 As shown, the FPGA-based synchronous acquisition circuit uses an FPGA controller to control multiple acquisition front-ends for synchronous measurement. A voltage generator produces a modulation voltage under FPGA control. Based on the charge at the collector, the transimpedance amplifier is designed with a bandwidth higher than the modulation signal frequency. The output signal of the transimpedance amplifier is converted to the digital domain by an analog-to-digital converter for signal processing. Multiple acquisition front-ends operate under the drive of a synchronization trigger signal, ensuring time-domain synchronization of the acquired signals. Typically, the synchronization accuracy can reach the 100ns level.

[0061] The shielding shell is made of conductive material and is wrapped around the outside of the measurement front-end components to prevent external electromagnetic interference from affecting the measurement results.

[0062] Different gate and grid fabrication and calibration methods require ensuring that the coaxiality error of the four-layer gate is as small as possible, ideally reaching <10μm.

[0063] By employing wireless charging and transmission modules, and utilizing wireless power supply and data transmission, the installation process is simplified. The wireless design enhances system flexibility and reduces interference factors that may introduce measurement noise. The use of wireless communication and wireless charging provides advantages such as interference resistance, flexible installation adaptability, real-time monitoring, and reduced maintenance complexity for the energy analysis and charge measurement device. It avoids the installation difficulties caused by connecting the probe to external power supply and measurement equipment via cables in existing technologies.

[0064] Preferably, the wireless communication module uses infrared or Bluetooth communication.

[0065] In engineering, physical wiring can disrupt the vacuum and interfere with plasma homogeneity; probe cables can even affect the normal function of mechanical moving parts such as the substrate. Employing infrared or Bluetooth communication technologies, which deviate significantly from the plasma radio frequency (RF) frequency, allows for low-cost and extremely low-power avoidance of RF interference. The system has no wiring penetrating the chamber; the measurement front-end with wireless communication capabilities is directly embedded in the substrate stage, eliminating the need for additional vacuum feedthroughs and simplifying chamber design. Wireless communication addresses signal integrity issues in the strong electromagnetic field environment of plasma, improving reliability and flexibility. An integrated wireless communication module enables data transmission and remote control.

[0066] Wireless charging technology, which transfers electrical energy without physical contact, is based on the electromagnetic induction effect. Designing a wireless charging system requires consideration of electromagnetic compatibility, thermal management, structural adaptability, and safety in high-precision measurement environments. Gallium nitride (GaN)-based high-frequency switching devices can be used; high-frequency switching reduces switching noise and avoids interference with ion current measurements. Simultaneously, the switching frequency design must avoid the typical RF frequencies and harmonic frequencies of the chamber.

[0067] like Figure 10 As shown, the wireless charging module includes a transmitting coil, a receiving coil, and a measurement front-end circuit. The input terminal of the transmitting coil is connected to the output terminal of the DC-AC high-frequency inverter circuit, and the output terminal is connected to the input terminal of the receiving coil. The output terminal of the receiving coil is connected to the input terminal of the AC-DC rectifier and filter circuit, and the output terminal of the AC-DC rectifier and filter circuit is connected to the measurement front-end circuit. The input terminal of the DC-AC high-frequency inverter circuit is connected to the AC / DC module and the chamber power supply module.

[0068] The transmitting coil is embedded in the non-measuring area (sidewall) of the measuring front end housing, with a thickness as small as possible, typically 3mm; the receiving coil can be a flexible printed circuit (FPC) that fits the internal curved surface of the device.

[0069] The system's accompanying professional software can display parameters such as ion energy distribution function (IEDF), average energy, and ion flow rate in real time, and supports data recording and trend analysis, facilitating process monitoring and fault diagnosis.

[0070] The collected data can be used to generate ion energy distribution and ion charge distribution (concentration) maps, as shown in Figure 11.

[0071] Figure 11(a) shows the measurement curves with different charge amounts at two peak energies of 80 eV and 130 eV; the two energy peak curves are clearly visible. Figure 11(b) shows the ion flux curves at the radial positions of the wafer obtained after mathematical fitting and smoothing by arranging multiple measurement front ends on the wafer; it can be seen that the peak ion flux is located at position 75 mm, and there is a local hot spot at position 30 mm. Overall, it shows a trend of high flux in the middle and low flux at both sides.

[0072] The ever-shrinking feature sizes in modern semiconductor manufacturing demand more precise control over plasma processes. The optimized ion energy and ion flux data provided in this invention can offer support for process development and optimization.

[0073] In summary, this invention utilizes phase-locked modulation and digital demodulation techniques to extract extremely weak (fA-pA level) ion current signals in plasma environments with strong radio frequency (RF) noise, improving measurement accuracy and energy resolution to the 0.1 eV level. Through multi-probe distributed synchronous measurement technology, it achieves microsecond-level time-resolved measurements of transient processes such as pulsed plasma and spatial distribution measurements of ion flux on large-area substrates. Furthermore, through highly integrated wireless design and optimized wireless communication / charging schemes, the measurement front end is fabricated into a wafer-like structure that can be directly embedded into the substrate stage, completely eliminating interference from physical cables, achieving true in-situ measurement, and ensuring reliability and flexibility even in environments with strong electromagnetic interference.

[0074] This invention effectively solves the problems of weak anti-interference ability, low time resolution, inability to perform spatial distribution measurement, and measurement error and installation complexity introduced by wired design in the prior art.

[0075] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

Claims

1. A method for measuring the energy and charge distribution of an ion beam, characterized in that, include: By grounding the inlet gate or applying a negative bias voltage, ions are screened to enter the measurement front end and the incident angle of the ion beam is controlled. A scanning voltage is applied to the deceleration gate to filter ions whose kinetic energy is higher than the scanning voltage potential; Scattered ions are filtered through the filter gate; Applying a negative bias voltage to the gate suppresses the escape of secondary electrons; The ion current is measured by collecting electrodes. The weak ion current signal is collected by the scanning generation and acquisition control circuit. The ion current signal is converted into a modulated scanning high voltage signal. The FPGA-based synchronous acquisition circuit at the measurement back end controls multiple probes to perform synchronous measurements on multiple measurement front ends. The measurement front end is powered by a wireless charging module, and the measurement data is transmitted to the measurement back end via a wireless communication module. The measurement front end includes an inlet gate, a deceleration gate, a filter gate, a suppression gate, a collection gate, a scan generation and acquisition control circuit, and a wireless charging module. The software analysis module at the measurement backend displays the ion energy distribution function and radial ion flux distribution in real time.

2. The method for measuring ion beam energy and charge distribution according to claim 1, characterized in that, The wireless communication module uses infrared or Bluetooth communication.

3. The method for measuring ion beam energy and charge distribution according to claim 1, characterized in that, The wireless charging module includes a transmitting coil, a receiving coil, and a measurement front-end circuit. The input terminal of the transmitting coil is connected to the output terminal of the DC-AC high-frequency inverter circuit, and the output terminal is connected to the input terminal of the receiving coil. The output terminal of the receiving coil is connected to the input terminal of the AC-DC rectifier and filter circuit, and the output terminal of the AC-DC rectifier and filter circuit is connected to the measurement front-end circuit. The input terminal of the DC-AC high-frequency inverter circuit is connected to the AC / DC module and the chamber power supply module.

4. The method for measuring ion beam energy and charge distribution according to claim 1, characterized in that, The scanning generation and acquisition control circuit acquires weak ion current signals, including: in, k Modulation depth; This is a phase delay, which is related to the plasma energy distribution; , This indicates the output current signal; Indicates the amplitude of the output signal. The reference signal for demodulation measurement; X、 It is an in-phase signal; Y、 Orthogonal signals; R The amplitude of the output signal; The phase angle of the output signal; The sine value of the reference signal, The cosine value of the reference signal.

5. A device for measuring ion beam energy and charge distribution, characterized in that, include: The measurement front end, integrated in a wafer-shaped substrate, includes: Shielding shell, The multi-layer gate structure disposed within the housing includes, in sequence along the ion incident direction, an inlet gate, a deceleration gate, a filter gate, a suppression gate, and a collector, with each gate separated by an insulating layer; A scanning generation and acquisition control circuit employing phase-locked modulation technology has its output terminal connected to the deceleration gate. The wireless communication module is used to transmit the acquired signal data to the measurement backend; A wireless charging module is used to provide power to the measurement front end; The measurement backend, wirelessly connected to the measurement frontend via a wireless communication module, includes: An FPGA-based synchronous acquisition circuit is used to receive data transmitted from a wireless communication module and simultaneously measure multiple measurement front-ends using multiple probes. The software analysis module is used to display the ion energy distribution function, average energy, and ion flux in real time.

6. The ion beam energy and charge distribution measuring device according to claim 5, characterized in that, At least one insulating layer includes a peripheral portion with a reduced thickness relative to the remainder of the insulating layer.

7. The ion beam energy and charge distribution measuring device according to claim 6, characterized in that, The outer portion of the insulating layer is convex or concave.

8. The ion beam energy and charge distribution measuring device according to claim 5, characterized in that, The filter gate is a curved grid structure, which is a curved surface formed by rotating about a parabolic axis of symmetry.

9. The ion beam energy and charge distribution measuring device according to claim 5, characterized in that, The scanning generation and acquisition control circuit includes a transimpedance amplifier I / V conversion module, a low-pass filter, a lock-in amplifier, a controller, and an acquisition circuit. The input terminal of the lock-in amplifier is connected to the low-pass filter and the reference modulation signal, respectively. The output terminal of the lock-in amplifier is connected to the input terminal of the acquisition circuit. The output terminal of the acquisition circuit is connected to the input terminal of the controller. The output terminal of the controller is connected to the reference modulation signal and the high-precision voltage source. The ion current signal passes sequentially through the transimpedance amplifier I / V conversion module, the low-pass filter, the lock-in amplifier, the acquisition circuit, the controller, the reference modulation signal, and the high-precision voltage source, and outputs a modulated scanning high-voltage signal.

10. The ion beam energy and charge distribution measuring device according to claim 5, characterized in that, The FPGA-based synchronous acquisition circuit generates a synchronous trigger signal, which is sent to the collector of the measurement front end through a wireless communication module, enabling multiple measurement front ends to perform synchronous measurements.

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