A rotating target magnetron sputtering device based on dynamic magnetic field compensation and control method

Abstract

The application discloses a rotating target magnetron sputtering equipment and method based on dynamic magnetic field compensation, aiming at improving target material utilization and film deposition uniformity. The equipment comprises a control system, an upper cover and a vacuum chamber, the upper cover is installed above the vacuum chamber, and a rotating target assembly is arranged in the upper cover; an excitation device one and an excitation device two are distributed in the periphery of the rotating target assembly in a circumferential direction; the rotating target assembly comprises a rotating shaft and a plurality of coaxial circumferential magnetic steel fixing assemblies arranged on the rotating shaft, the rotating shaft extends into the vacuum chamber, the target material is detachably packaged at the bottom end of the rotating shaft, and a magnetic field monitoring unit one and a magnetic field monitoring unit two are arranged at the top of the vacuum chamber in the periphery of the target material; and the sample table is located at the lower part of the vacuum chamber. The application realizes millisecond-level coordinated regulation by measuring the magnetic field distribution data of the target material surface and the near surface through the magnetic field monitoring unit, and combining the plasma density, electron temperature, target material ion characteristic spectrum and other parameters obtained through the plasma monitoring unit and the target material ion monitoring unit.

Description

Technical Field

[0001] This invention belongs to the field of magnetron sputtering coating technology, specifically relating to a rotating target magnetron sputtering device and control method based on dynamic magnetic field compensation. Background Technology

[0002] Magnetron sputtering, as a highly efficient physical vapor deposition method, has been widely used in the preparation of functional thin films such as semiconductors, optical thin films, and decorative coatings. Rotating target magnetron sputtering equipment, by continuously rotating a cylindrical target, effectively improves target utilization and reduces localized erosion and nodulation on the target surface, demonstrating significant advantages in large-scale industrial production.

[0003] However, traditional rotating target magnetron sputtering equipment has an inherent drawback: the static magnetic field generated by the magnet assembly fixedly installed inside the rotating target creates relative motion with the rotating target surface, resulting in periodic fluctuations in the magnetic field distribution on the target surface. This magnetic field inhomogeneity directly causes uneven plasma density distribution, leading to problems such as uneven film thickness and inconsistent microstructure.

[0004] In existing technologies, several improvement schemes have emerged to address the problem of uneven magnetic fields. Domestic and international solutions to this problem mainly focus on optimizing the static arrangement of permanent magnets, such as using Halbach arrays (Structural Design and Magnetic Field Analysis of Rotating Cathode Magnetic Field Devices for Magnetron Sputtering, *Electrical Machines and Control Applications*, 2024, 51(03)) or optimizing the magnetic pole shape. While these methods can improve the initial magnetic field distribution to some extent, they cannot respond to the real-time dynamic changes in the magnetic field during target rotation. The dynamic magnetic field rectangular planar magnetron sputtering target developed by Beijing North China Vacuum Technology Co., Ltd. expands the etching area by horizontally and vertically moving the magnet assembly on the planar target (Development of Dynamic Magnetic Field Rectangular Planar Magnetron Sputtering Target, *Vacuum*, 2023, 60(05)). However, this technology targets planar targets and uses a mechanical scanning method, which cannot solve the circumferential magnetic field fluctuation problem unique to rotating targets. Xiaorui Vacuum Equipment (Jiaxing) Co., Ltd.'s patent application for "Online Oscillating Adjustable Magnetic Rod for Magnetron Sputtering" (Publication No. CN119800314A) uses multiple independently controlled adjustment components to locally change the distance between the magnetic yoke and the sputtering target surface, thereby adjusting the local magnetic field strength. Although this method achieves online adjustment, it is essentially a mechanical distance adjustment, and its response speed and the complexity of its application within the rotating target limit its effectiveness. Furthermore, Wuxi Shangji Semiconductor Technology Co., Ltd.'s patent application for "Magnetron Sputtering Device and Method for Improving Plasma Uniformity" (Publication No. CN119243101A) improves plasma uniformity by setting coil components between the target and the wafer to form a magnetic field track. This is an external magnetic field compensation method, not a direct compensation for the dynamic magnetic field fluctuations on the rotating target's surface.

[0005] In recent years, some research institutions have begun to explore more advanced magnetic field control technologies. The variable magnetic field magnetron sputtering coating device developed by the Institute of Electrical Engineering, Chinese Academy of Sciences, regulates the magnetic field distribution by adjusting the current and direction of the inner and outer electromagnetic coils in the cathode magnet; however, this technology is mainly applied to planar cathode systems. Furthermore, existing technologies such as the patent "A sputtering method and sputtering equipment for improving the utilization rate of rotating targets" (application number CN202210506190.9) propose a method for adjusting the magnetic field strength online according to the target morphology, but its adjustment is based on the target morphology rather than the real-time magnetic field distribution, and it does not involve dynamic compensation of the circumferential magnetic field of the rotating target.

[0006] Therefore, developing a magnetron sputtering device and method that can non-mechanically monitor and actively compensate for the dynamic inhomogeneity of the magnetic field on the surface of a rotating target in real time has become the key to improving the quality of high-end thin film preparation. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of existing rotating target magnetron sputtering technology and provide a rotating target magnetron sputtering device based on dynamic magnetic field compensation. This device can monitor and compensate for magnetic field fluctuations during target rotation in real time through a non-mechanical electromagnetic compensation principle, thereby significantly improving the uniformity and consistency of thin film deposition.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A rotating target magnetron sputtering apparatus based on dynamic magnetic field compensation includes a control system, a top cover, a vacuum chamber, and a sample stage. The top cover is installed above the vacuum chamber and houses a rotating target assembly. Excitation devices one and two are circumferentially distributed around the rotating target assembly. The rotating target assembly includes a rotating shaft and multiple sets of coaxially circumferentially arranged magnet fixing assemblies. The rotating shaft extends into the vacuum chamber, and a target material is detachably encapsulated at the bottom end of the rotating shaft. Magnetic field monitoring units one and two are located on the top of the vacuum chamber around the target material. The sample stage is located at the bottom of the vacuum chamber, and a substrate is placed on the sample stage, with its core connected to the rotating components. A plasma monitoring unit is installed in the vacuum chamber near the sample stage. A plasma generation unit and a target ion monitoring unit are provided on the side wall of the vacuum chamber to align the space between the target material and the substrate.

[0009] Preferably, a spectral window is provided on the side wall of the vacuum chamber, the detection end of the target ion monitoring unit is located in the spectral window, and its output end is connected to the fiber optic spectrometer.

[0010] Preferably, the rotating shaft is circumferentially fixed with a magnet fixing component one, a magnet fixing component two, and a magnet fixing component three.

[0011] Preferably, both the magnetic field monitoring unit one and the magnetic field monitoring unit two are composed of high-temperature Hall effect sensors. Each sensor is installed on the top of the vacuum chamber along the outer periphery of the target material, and the circumferential angle between adjacent sensors is equal.

[0012] Preferably, both excitation device one and excitation device two include an electromagnetic coil group and a soft magnetic material frame. The electromagnetic coil group includes radial coils and axial coils. Each coil is wound on the soft magnetic material frame, and the radial coils and axial coils are arranged orthogonally to form a two-dimensional magnetic field adjustment capability.

[0013] Preferably, the plasma monitoring unit mainly includes a Langmuir probe and a vacuum feedthrough. The Langmuir probe is introduced into the vacuum chamber through the vacuum feedthrough, and its head is exposed to the plasma region near the surface of the target material.

[0014] Preferably, the control system is electrically connected to the drive mechanism of magnetic field monitoring unit 1, magnetic field monitoring unit 2, excitation device 1, excitation device 2, plasma monitoring unit, plasma generation unit, and rotating target assembly, respectively, for receiving signals and outputting control commands.

[0015] A control method for a rotating target magnetron sputtering device based on dynamic magnetic field compensation, comprising the following steps: S1. Equipment Initialization: During the initialization stage, set the target magnetic field distribution B0(r,θ,z) on the target surface and the plasma density threshold n0, and start vacuuming to 10. -4 After the pressure drops below Pa, introduce working gas and maintain the pressure between 0.1 and 1 Pa. S2. Real-time monitoring: The magnetic field monitoring unit collects the actual magnetic field distribution near the target surface in real time at a sampling frequency of 100Hz to 1kHz. a (r,θ,z,t), while the plasma monitoring unit measures the plasma density n(r,θ,z,t) and electron temperature T. e (t), the target ion monitoring unit measures the intensity of the characteristic spectral line I(t) of the target ion; S3. Deviation Calculation: The control system defines the magnetic field spatial deviation according to the following formula: ΔB(r,θ,z,t)=B a (r,θ,z,t)-B0(r,θ,z), Where r is the radial distance (from the central axis), θ is the circumferential angle, z is the axial height (along the target tube direction), and t is the time variable; S4. Dynamic Compensation: The control system is based on a plasma coupling model. n(r,θ,z,t)=k1·B a (r,θ,z,t)+k2·T e (t)+k3·I(t), Calculate plasma density deviation: Δn(r,θ,z,t)=n(r,θ,z,t)-n0, The compensation magnetic field is calculated using the following PID algorithm: , The compensation magnetic field is converted into a driving current: , It also controls the electromagnetic coil group to generate a compensating magnetic field according to the driving current, which is superimposed on the original magnetic field to achieve dynamic regulation; In the formula, k1, k2, and k3 are fitting coefficients, N is the number of coil turns, μ0 is the free permeability, and L is the equivalent length of the coil; because the rotating target has axisymmetry, cylindrical coordinates are more natural, T e(t) represents the electron temperature; S5. Repeat the real-time monitoring, deviation calculation, and dynamic compensation steps in a closed-loop iteration until |ΔB(r,θ,z,t)|≤5%·|B0(r,θ,z)| and |Δn(r,θ,z,t)|≤10%·n 0。

[0016] Preferably, in step S4, when I(t) deviates from the preset threshold I0 by ±15%, the sputtering power P(t) needs to be adjusted synchronously as follows: P(t)=P0·[1+λ·(I0-I(t)) / I0], In the formula, P0 is the initial power and λ is the power adjustment coefficient.

[0017] Preferably, in step S4, the proportional coefficient K in the PID algorithm is... p Corrected to K p '=K p ·P(t) / P0, and with the corrected K p 'Replace K' p Participating in the compensation magnetic field B c The calculation.

[0018] Advantages of this invention: This invention uses a magnetic field monitoring unit to measure the magnetic field distribution data of the target surface and near the surface in real time. Simultaneously, it combines parameters such as plasma density, electron temperature, and target ion characteristic spectral lines obtained from a plasma monitoring unit and a target ion monitoring unit. The control system performs multi-parameter coupling analysis based on a preset magnetic field-plasma collaborative calculation model, dynamically calculates the required compensation magnetic field using a PID control algorithm, and drives a circumferentially segmented electromagnetic coil group to generate a precise compensation magnetic field, achieving millisecond-level closed-loop control of the magnetic field distribution on the target surface. This dynamic compensation mechanism effectively overcomes the problem of uneven plasma distribution caused by traditional fixed magnetic fields. Through the synergistic optimization of the magnetic field and plasma, the plasma is always confined to the optimal region, thereby significantly improving target utilization and thin film deposition uniformity. Attached Figure Description

[0019] Figure 1 : A schematic diagram of the structure of the device of the present invention; Figure 1In the middle, there are: vacuum chamber 001; sample stage 002; substrate 003; rotating component 004; plasma generation unit 005; guiding electromagnetic unit 006; plasma monitoring unit 007; target ion monitoring unit 008; exhaust gas outlet 009; top cover 010; rotating target assembly 101; rotating shaft 102; magnet fixing assembly one 103; magnet fixing assembly two 104; magnet fixing assembly three 105; target material 106; magnetic field monitoring unit one 201; magnetic field monitoring unit two 202; excitation device one 203; excitation device two 204; electromagnetic coil group one 205; electromagnetic coil group two 206; and control system 301. Figure 2 Top view of the device of the present invention; Figure 3 Another structural schematic diagram of the device of the present invention; Figure 4 : Figure 3 3D structural diagram of the structure shown; Figure 5 : Main flowchart of the method of the present invention. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0021] Example 1: As Figure 1 , 2 As shown. The equipment structure includes a vacuum chamber 001, a sample stage 002, a substrate 003, and a top cover 010; the vacuum chamber 001 is a double-layered stainless steel water-cooled cavity, connected to standard vacuum equipment and an inert gas supply device, and has an exhaust outlet 009 and related valve components at its bottom. Its ultimate vacuum is better than 1×10⁻⁶. -5 Pa.

[0022] The sample stage 002 is located at the lower part of the vacuum chamber 001, and the substrate 003 is placed on it. The upper cover 010 is installed on the top of the vacuum chamber 001, and integrates a rotating target assembly 101 inside; the rotating target assembly 101 mainly consists of a drive mechanism, a magnet fixing assembly, and a rotating shaft 102 that penetrates the upper cover 010 and extends into the vacuum chamber 001 through a dynamic sealing structure. Multiple sets of magnet fixing assemblies are coaxially arranged on the rotating shaft 102—magnet fixing assembly one 103, magnet fixing assembly two 104, and magnet fixing assembly three 105. The three are arranged sequentially along the circumference and are all axially limited and radially constrained by non-magnetic end caps (such as titanium alloy or high-strength engineering plastic). The target material 106 is detachably encapsulated at the bottom end of the rotating shaft of the rotating target assembly 101 for easy replacement and maintenance.

[0023] On the outer periphery of the target 106, magnetic field monitoring unit 1 201 and magnetic field monitoring unit 202 are circumferentially arranged on the top of the vacuum chamber 001. Magnetic field monitoring unit 1 and magnetic field monitoring unit 2 mainly employ high-temperature Hall effect sensors (operating temperature range -40℃~200℃, response time ≤1μs). Each high-temperature Hall effect sensor is embedded in a circular array along the outer periphery of the target 106 on the inner wall of the top of the vacuum chamber 001 or its supporting ring. The circumferential angle between adjacent sensors is equal. A typical arrangement is 8 points evenly distributed circumferentially + 2 layers of axial misalignment, realizing the monitoring of the magnetic field vector B in the three-dimensional space (r,θ,z). a Synchronous sampling of (r,θ,z,t); the sampling frequency is set to 500Hz to meet the Nyquist sampling requirements when the target material rotates at 60rpm.

[0024] Excitation device 1 203 and excitation device 2 204 respectively include electromagnetic coil group 1 205 and electromagnetic coil group 2 206 and a soft magnetic material skeleton. Each electromagnetic coil group includes radial coils and axial coils, specifically arranged as follows: layered along the axial direction (3 layers) and segmented circumferentially (8 segments per layer). Each segment contains mutually orthogonal radial and axial coils. The soft magnetic material skeleton uses a high-permeability soft magnetic material (such as Fe-Si-Al nanocrystalline alloy). The radial and axial coils are wound on the soft magnetic material skeleton to ensure low eddy current loss and high magnetic field response bandwidth. Electromagnetic coil group 1 205 and electromagnetic coil group 2 206 together constitute a two-dimensional vector magnetic field adjustment capability, which can synthesize a compensation magnetic field B with arbitrary direction and controllable amplitude in the near-surface space of the target material 106. c (r,θ,z,t).

[0025] The sample stage 002 is located at the lower part of the vacuum chamber 001. The sample stage 002 is driven by a rotating component 004 to achieve a combined rotational and radial translational motion. The rotating component 004 is a servo motor, and its output shaft is connected to the central shaft of the sample stage 002 via a precision coupling to achieve rotational motion. The rotational speed is continuously adjustable from 0 to 100 rpm. The translational mechanism is driven by a linear guide rail and a stepper motor to move the sample stage radially. The positioning accuracy is ±1 μm, which supports the substrate 003 to scan radially along the target material 106, expanding the dimension of deposition uniformity control.

[0026] A plasma monitoring unit 007 is installed in the vacuum chamber 001 near the sample stage 002. This unit mainly includes a Langmuir probe and a vacuum feedthrough. The Langmuir probe is introduced through the vacuum feedthrough, with its tip exposed in the plasma sheath region 5–10 mm from the surface of the target material 106. This is used for in-situ measurement of plasma density n(r,θ,z,t) and electron temperature T. e (t), sampling is synchronized with magnetic field monitoring unit 1 201 and magnetic field monitoring unit 2 202, and the timestamp alignment error is ≤100ns.

[0027] A plasma generation unit 005 and a target ion monitoring unit 008 are provided on the side wall of the vacuum chamber 001 to align the space between the target 106 and the substrate 003.

[0028] The plasma generation unit (005) uses a DC sputtering power supply with a maximum power of 5 kW and an adjustable operating current (0~3A). The plasma generation unit (005) integrates a guiding electromagnetic unit (006) made of soft magnetic material, an excitation coil, and other components. An adjustable focusing magnetic pole system based on soft magnetic material and excitation coil is used to guide the plasma to focus onto the target area.

[0029] The target ion monitoring unit 008 employs fiber optic detection. Its detection end, such as the fiber optic image transmission bundle, endoscopic imaging probe, and fiber optic lens, is aligned with the sputtering plume region between the target 106 and the substrate 003 through a quartz spectral window located on the side wall of the vacuum chamber 001. Its output end is connected to an external fiber optic spectrometer (resolution ≤ 0.1 nm) via the other end of the fiber optic cable to acquire characteristic ion spectra of the target 106 in real time (such as Ar). + 488.0nm, Ti + The intensity I(t) at 334.9 nm reflects the dynamic changes in sputtering output.

[0030] The control system 301 is electrically connected to the magnetic field monitoring unit 1 201, magnetic field monitoring unit 202, excitation device 1 203, excitation device 2 204, plasma monitoring unit 007, plasma generation unit 005, and the drive mechanism of the rotating target assembly 101, respectively, for receiving signals and outputting control commands. The control system 301 uses an industrial-grade PLC (e.g., Siemens S7-1515F), whose input ports are connected to all sensor signal lines (including Hall voltage, probe IV curve, and analog spectral intensity), and whose output ports are connected to the drive circuits of electromagnetic coil group 1 205 and electromagnetic coil group 2 206 via a power amplifier module (bandwidth DC~10kHz, current output 0~20A). The control system 301 has an embedded real-time control algorithm module that executes the following process flow: In the initialization phase (step S1), the target magnetic field distribution B0(r,θ,z) on the surface of target material 106 is set. This distribution is an axisymmetric uniform field, where the axial component B0z = 50 mT and the radial component B0r = 20 mT. Simultaneously, the plasma density threshold n0 = 1.2 × 10⁻⁶ mT is set. 17 m -3 Start the molecular pump unit to evacuate to ≤1×10 -4 After Pa, argon gas with a purity ≥99.999% is introduced, and the gas flow rate is precisely controlled to 50 sccm by a mass flow controller to maintain the working pressure at 0.3 Pa.

[0031] During the real-time monitoring phase (step S2), magnetic field monitoring unit 1 (201) and magnetic field monitoring unit 2 (202) continuously collect data on the actual magnetic field distribution. a (r,θ,z,t), the plasma monitoring unit 007 synchronously acquires n(r,θ,z,t) and T. e (t), the target ion monitoring unit 008 synchronously records I(t); all data are stored in the high-speed cache of the control system 301 with a unified time base. The sampling frequency is 500Hz, and the plasma monitoring unit 007 and the target ion monitoring unit 008 acquire data synchronously with timestamps aligned. T e (t) represents the electron temperature.

[0032] In the deviation calculation stage (step S3), the control system 301 first calculates the magnetic field spatial deviation: ΔB(r,θ,z,t)=B a (r,θ,z,t)-B0(r,θ,z), In the formula, r is the radial distance (from the central axis), θ is the circumferential angle, z is the axial height (along the target tube direction), t is the time variable, B0(r,θ,z) is the target magnetic field distribution, and B... a (r,θ,z,t) represents the actual magnetic field distribution; Subsequently, in the compensation execution phase (step S4), the control system 301 is based on the plasma coupling model: n(r,θ,z,t)=k1·B a (r,θ,z,t)+k2·T e (t)+k3·I(t), Calculate plasma coupling deviation: Δn(r,θ,z,t)=n(r,θ,z,t)-n0, The fitting coefficient is taken as k1=0.1m -3 / mT, k2=0.05m -3 / eV, k3=0.01m -3 / au, Furthermore, during the compensation execution phase, an incremental PID algorithm is used to generate compensation magnetic field commands: B c (r,θ,z,t)=K p ·ΔB(r,θ,z,t)+K i ·∫ΔB(r,θ,z,t)dt+K d ·dΔn(r,θ,z,t) / dt, where the integral term ∫ΔB(r,θ,z,t)dt is discretized using the trapezoidal rule, and the differential term is calculated using the forward difference approximation.

[0033] In the formula, k1, k2, and k3 are fitting coefficients, N is the number of coil turns, μ0 is the free magnetic permeability, and L is the equivalent length of the coil; due to the axisymmetric nature of the rotating target, cylindrical coordinates are more natural; the initial PID parameters are K p =0.5, K i =0.1, K d =0.05.

[0034] B c Convert to drive current command: , In the formula, N = 1000 turns, L = 0.05 m, and μ0 = 4π × 10⁻⁶. -7 H / m; This current command, after being amplified by power, drives electromagnetic coil group one 205 and electromagnetic coil group two 206 to generate a superimposed magnetic field, thereby achieving dynamic correction of the original magnetic field.

[0035] In the closed-loop control phase (step S5), the system continuously executes the above monitoring-deviation calculation-compensation output cycle, and iterates in the closed loop; when the judgment condition |ΔB(r,θ,z,t)|≤5%·|B0(r,θ,z)| and |Δn(r,θ,z,t)|≤10%·n0; When both conditions are met, the system enters a stable sputtering state, maintaining constant operation of the current compensation parameters.

[0036] Furthermore, in the compensation execution phase (step S4), when the I(t) collected by the target ion monitoring unit 008 deviates from the preset threshold I0 (I0 is calibrated according to the target material 106 and the sputtering mode, such as I0=1200 a.u. for Ti targets) by more than ±15%, the power adaptive mechanism is triggered: P(t)=P0·[1+λ·(I0-I(t)) / I0], The power regulation coefficient λ is set to 0.5, P0 is initially set to 2kW, and the corrected K p It is updated in real time to the control system algorithm module.

[0037] Simultaneously adjust the proportional gain proportionally: K p =K p ·P(t) / P0, and update K p Real-time loading of the PID control module, with K p 'Replace K' p Participating in the compensation magnetic field B c The calculation ensures dynamic matching between the magnetic field compensation response and the sputtering energy input.

[0038] Example 2: As Figure 3 , 4As shown, unlike Embodiment 1, in this device, the target material 106 is detachably encapsulated on the outer periphery of the bottom of the rotating shaft 102 in the rotating target assembly 101, which can also realize the sputtering function.

[0039] The process flow is as follows: like Figure 5 Furthermore, it can be seen that the process flow of the present invention is based on the main line of "vacuum preparation → magnetic field calibration → dynamic compensation start-up → steady-state sputtering → power coordinated adjustment → process termination". The entire process is automatically scheduled by the control system 301 without manual intervention.

[0040] Step 1: Vacuum Preparation. Close the vacuum chamber door 001, start the mechanical pump for rough evacuation to 5 Pa, then switch to the molecular pump group and continue evacuating until the pressure reaches ≤1×10⁻⁶ Pa. -4 Pa; turn on the argon mass flow controller, set the flow rate to 50 sccm, and after the gas pressure stabilizes at 0.3 Pa, apply a negative bias voltage (-50V) to the sample stage 002 for plasma pre-glow cleaning for 5 min.

[0041] Step 2: Magnetic field calibration and real-time monitoring. In the absence of plasma, using the stationary target 106 as a reference, the initial distribution of B0(r,θ,z) in the entire space is collected by magnetic field monitoring unit 1 201 and magnetic field monitoring unit 202, and stored in the memory of the control system 301 as a reference for subsequent dynamic compensation; at the same time, the plasma monitoring unit 007 and the target ion monitoring unit 008 are zero-point calibrated and gain calibrated.

[0042] Step 3: Deviation calculation and dynamic compensation initiation. Start the rotating target assembly 101 and set the rotation speed to 30 rpm; the control system 301 synchronously activates the magnetic field monitoring unit 1 201, magnetic field monitoring unit 202, plasma monitoring unit 007, and target ion monitoring unit 008, and begins continuous acquisition at a frequency of 500 Hz; the first frame of data triggers the PID controller to output the initial compensation current, and electromagnetic coil group 1 205 and electromagnetic coil group 2 206 respond instantly to form the first round of magnetic field superposition; thereafter, a complete closed-loop calculation (including sampling, deviation calculation, PID output, current conversion and driving) is completed every 2 ms to ensure that the compensation lag time is <5 ms.

[0043] Step 4: Steady-state sputtering. This is achieved when |ΔB|≤2.5mT and |Δn|≤1.2×10⁻⁶ consecutively. 16 m -3 When the system enters a steady state, the sputtering power supply is applied to the target 106 at a constant power of 2kW, and the temperature of the substrate 003 is controlled to 300℃ by the heating stage, and thin film deposition begins; the sample stage 002 simultaneously starts rotating (10rpm) and radial scanning (0.1mm / s) to cover the entire arc surface of the target 106.

[0044] Step 5: Power Coordination Adjustment. During the deposition process, if I(t) exceeds the [1020, 1380]au range for 5 consecutive samplings, the power adjustment formula is activated to calculate P(t), and K is updated synchronously. p The new power command is issued via the sputtering power supply communication interface (RS485 / Modbus), with an adjustment response time ≤100ms; K p The updated code immediately participates in the next cycle of PID calculation to avoid magnetic field compensation lagging behind power changes.

[0045] Step 6: Process Termination. When the preset deposition time is reached or the film thickness monitoring signal meets the standard, the control system 301 sequentially shuts off the sputtering power supply, stops the rotation of the rotating target assembly 101, shuts off the argon gas, and breaks the vacuum. All data (magnetic field, plasma, spectrum, power, current) are automatically stored in CSV format with a time resolution of 2ms, supporting process backtracking and parameter optimization.

[0046] In summary, this invention, based on the principle of electromagnetic field vector superposition and closed-loop feedback control theory, solves the problem of magnetic field inhomogeneity in rotating target magnetron sputtering by combining real-time monitoring and dynamic compensation. Its core principles include: Principle of dynamic magnetic field monitoring: Based on the Hall effect, distributed Hall sensors are used to measure the magnetic induction intensity and direction at different locations on the target surface in real time. The sensor output is a Hall voltage proportional to the magnetic field intensity. After signal conditioning and acquisition, the voltage is sent to the control system to construct a real-time magnetic field distribution map of the target surface.

[0047] Dynamic magnetic field compensation principle: The control system compares the real-time magnetic field distribution with the preset target distribution and calculates the magnetic field vector deviation at each compensation point. Based on the deviation value, the required drive current for each electromagnetic coil group is calculated using a PID control algorithm. The energized electromagnetic coils generate a compensation magnetic field, which is vector-superimposed with the permanent magnet's magnetic field, achieving precise cancellation of dynamic deviations. This process is purely electromagnetic compensation, unlike mechanical adjustment, and has a faster response speed.

[0048] Plasma coordinated control principle: A uniform magnetic field is conducive to the formation of plasma with uniform distribution and stable density. The plasma monitoring unit provides real-time feedback on the plasma state. If the plasma state is not ideal, the control system can coordinately adjust the compensation magnetic field parameters and sputtering power, constrain the plasma by fine-tuning the magnetic field shape, or adjust the plasma density and energy by changing the sputtering power, thereby achieving optimized control of the plasma environment. This mechanism differs from methods that only improve plasma distribution by applying an external magnetic field track.

Claims

1. A control method for a rotating target magnetron sputtering device based on dynamic magnetic field compensation, the device comprising a control system (301), a top cover (010), a vacuum chamber (001), and a sample stage (002), wherein a plasma monitoring unit (007) is installed in the vacuum chamber (001) near the sample stage (002), characterized in that: The upper cover (010) is installed above the vacuum chamber (001). A rotating target assembly (101) is provided inside the upper cover (010). Excitation device one (203) and excitation device two (204) are distributed circumferentially around the rotating target assembly (101). The rotating target assembly (101) includes a rotating shaft (102) and multiple sets of magnet fixing assemblies arranged coaxially and circumferentially on the rotating shaft (102). A plasma generation unit (005) and a target ion monitoring unit (008) are provided on the side wall of the vacuum chamber (001) to align the space between the target material (106) and the substrate (003). A magnetic field monitoring unit one (201) and a magnetic field monitoring unit two (202) are provided on the top of the vacuum chamber (001) around the target material (106). The method includes the following steps: S1. Equipment Initialization: During the initialization stage, set the target magnetic field distribution B0(r,θ,z) on the target surface and the plasma density threshold n0, and start vacuuming to 10. -4 After the pressure drops below Pa, introduce working gas and maintain the pressure between 0.1 and 1 Pa. S2. Real-time monitoring: The magnetic field monitoring unit collects the actual magnetic field distribution near the target surface in real time at a sampling frequency of 100Hz to 1kHz. a (r,θ,z,t), while the plasma monitoring unit measures the plasma density n(r,θ,z,t) and electron temperature T. e (t), the target ion monitoring unit measures the intensity of the characteristic spectral line I(t) of the target ion; S3. Deviation Calculation: The control system defines the magnetic field spatial deviation according to the following formula: ΔB(r,θ,z,t)=B a (r,θ,z,t)-B0(r,θ,z), Where r is the radial distance, θ is the circumferential angle, z is the axial height, and t is the time variable; S4. Dynamic Compensation: The control system is based on a plasma coupling model. n(r,θ,z,t)=k1·B a (r,θ,z,t)+k2·T e (t)+k3·I(t), Calculate plasma density deviation: Δn(r,θ,z,t)=n(r,θ,z,t)-n0, The compensation magnetic field is calculated using the following PID algorithm: ， The compensation magnetic field is converted into a driving current: ， It also controls the electromagnetic coil group to generate a compensating magnetic field according to the driving current, which is superimposed on the original magnetic field to achieve dynamic regulation; In the formula, k1, k2, and k3 are fitting coefficients, N is the number of coil turns, μ0 is the free permeability, and L is the equivalent length of the coil; because the rotating target has axisymmetry, cylindrical coordinates are more natural, and T e (t) represents the electron temperature; S5. Repeat the real-time monitoring, deviation calculation and dynamic compensation steps, and iterate in a closed loop until |ΔB(r,θ,z,t)|≤5%·|B0(r,θ,z)| and |Δn(r,θ,z,t)|≤10%·n0.

2. The control method for a rotating target magnetron sputtering device based on dynamic magnetic field compensation according to claim 1, characterized in that: The vacuum chamber (001) has a spectral window on its side wall. The detection end of the target ion monitoring unit (008) is located in the spectral window, and its output end is connected to the fiber optic spectrometer.

3. The control method for a rotating target magnetron sputtering device based on dynamic magnetic field compensation according to claim 1, characterized in that: Both the magnetic field monitoring unit one (201) and the magnetic field monitoring unit two (202) are composed of high-temperature Hall effect sensors. Each sensor is installed on the top of the vacuum chamber (001) along the outer periphery of the target material (106), and the circumferential angle between adjacent sensors is equal.

4. The control method for a rotating target magnetron sputtering device based on dynamic magnetic field compensation according to claim 1, characterized in that: The plasma monitoring unit (007) includes a Langmuir probe and a vacuum feedthrough. The Langmuir probe is introduced into the vacuum chamber through the vacuum feedthrough and exposed to the near-surface plasma region of the target material (106).

5. The control method for a rotating target magnetron sputtering device based on dynamic magnetic field compensation according to claim 1, characterized in that: In step S4, when I(t) deviates from the preset threshold I0 by ±15%, the sputtering power P(t) needs to be adjusted synchronously as follows: P(t)=P0·[1+λ·(I0-I(t)) / I0], In the formula, P0 is the initial power and λ is the power adjustment coefficient.

6. The control method for a rotating target magnetron sputtering device based on dynamic magnetic field compensation according to claim 5, characterized in that: In step S4, the proportional coefficient K in the PID algorithm is... p Corrected to K p '=K p ·P(t) / P0, and with the corrected K p 'Replace K' p Participating in the compensation magnetic field B c The calculation.

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