Single-chip microcomputer-based automatic control method and system for magnetron sputtering power supply

Abstract

This invention provides a microcontroller-based automatic control method and system for magnetron sputtering power supplies, belonging to the field of power supply control technology. The method includes: acquiring a target voltage through a three-phase four-wire input terminal; filtering the target voltage to generate a first DC voltage, converting it, determining a second DC voltage, modulating the second DC voltage, and applying it to the primary winding of a switching transformer; controlling the primary winding of the switching transformer through a push-pull switching signal output by the microcontroller to obtain an output DC operating voltage; and performing closed-loop control and regulation of the magnetron sputtering power supply by real-time acquisition of the output current and combining it with the output DC operating voltage. This solves the technical problems of existing magnetron sputtering power supplies, such as the inability to accurately track output power changes with process variations in real time and poor control precision. Through three-phase rectification and filtering and push-pull PWM closed-loop control, real-time tracking and stable regulation of output power are achieved, improving the technical effect of power supply output stability.

Description

Technical Field

[0001] This invention relates to the field of power control technology, specifically to an automatic control method and system for magnetron sputtering power supplies based on a microcontroller. Background Technology

[0002] Magnetron sputtering power supplies are critical energy supply devices in semiconductor and film deposition processes, and their output characteristics directly affect the film deposition rate, uniformity, and film quality. Existing magnetron sputtering power supplies mostly employ open-loop control or constant-voltage control based on the output voltage, achieving energy output by adjusting the PWM duty cycle. However, due to the significant nonlinear characteristics of the magnetron sputtering plasma load, its impedance dynamically changes with vacuum level, target condition, and discharge state, resulting in a nonlinear relationship between voltage and current. Under these circumstances, relying solely on voltage or a fixed duty cycle for control makes it difficult to accurately reflect actual output power changes, easily causing output power drift or transient fluctuations, thus affecting the stability of the sputtering process.

[0003] Existing technologies often employ open-loop or constant-voltage control methods in magnetron sputtering power supplies, resulting in poor control accuracy and the inability to accurately track output power changes in real time as the process changes. Summary of the Invention

[0004] The purpose of this application is to provide an automatic control method and system for magnetron sputtering power supplies based on a single-chip microcomputer, in order to solve the technical problem that existing magnetron sputtering power supplies mostly adopt open-loop or constant voltage control methods, resulting in the inability to accurately track output power changes with process variations in real time and poor control precision.

[0005] In view of the above problems, this application provides an automatic control method and system for magnetron sputtering power supply based on a microcontroller.

[0006] The first aspect of this application provides an automatic control method for a magnetron sputtering power supply based on a microcontroller. The method includes: acquiring a target voltage through a three-phase four-wire input terminal; filtering the target voltage to generate a first DC voltage; converting the first DC voltage to determine a second DC voltage; modulating the second DC voltage and applying it to the primary winding of a switching transformer; controlling the primary winding of the switching transformer by using a push-pull switching signal output by the microcontroller to obtain an output DC operating voltage; and real-time acquisition of the output current combined with the output DC operating voltage for closed-loop control and regulation of the magnetron sputtering power supply.

[0007] Optionally, multi-stage EMI filtering is performed based on the target voltage to generate an AC voltage; the AC voltage is applied to a three-phase full-bridge rectifier to generate a three-phase AC waveform; the three-phase AC waveform is rectified by full-wave rectification to output a pulsating DC voltage; capacitor energy storage filtering is performed based on the pulsating DC voltage, and common-mode inductor high-frequency noise suppression is performed according to the filtering result to generate a first DC voltage.

[0008] Optionally, the first DC voltage is connected to the input terminal of the push-pull topology, and the control terminals of multiple power transistors are connected to a microcontroller. The microcontroller performs two-way phase complementarity according to a preset switching frequency to generate a pulse width modulation signal. Based on the pulse width modulation signal, the power transistors of the push-pull topology are alternately driven to conduct. The power transistors of the push-pull topology include a first power transistor and a second power transistor. When the first power transistor is turned on, a current loop is generated. Based on the current loop, a positive pulse voltage is converted to modulate the first DC voltage to generate the second DC voltage. When the second power transistor is turned on, a reverse pulse voltage is generated. Based on the reverse pulse voltage, the first DC voltage is modulated to generate the second DC voltage.

[0009] Optionally, the multi-channel pulse width modulation (PWM) signals from the microcontroller are extracted, and these signals are applied to multiple power transistors in a push-pull power converter circuit for alternating conduction control to generate a first control result; the PWM signals are then applied to the same power transistors for alternating turn-off control to generate a second control result; voltage modulation is performed based on the first and second control results to generate high-frequency alternating pulse voltage parameters; these parameters are applied to the primary winding of a switching transformer for secondary induction to generate high-frequency alternating voltage parameters; and diode rectification is performed based on these parameters to obtain the output DC operating voltage.

[0010] Optionally, based on the analysis of the multi-channel pulse width modulation signals, a first pulse width modulation signal and a second pulse width modulation signal are extracted; the push-pull power conversion circuit includes a first power transistor and a second power transistor; the first pulse width modulation signal is connected to the gate driving terminal of the first power transistor in the push-pull power conversion circuit, and the second pulse width modulation signal is connected to the gate driving terminal of the second power transistor; when the first pulse width modulation signal is at an active level, the first power transistor is turned on, generating a positive magnetic flux, and the positive magnetic flux is added to the first control result as a positive conduction record; when the second pulse width modulation signal is at an active level, the second power transistor is turned on, generating a reverse magnetic flux, and the reverse magnetic flux is added to the first control result as a reverse conduction record.

[0011] Optionally, signal analysis is performed based on the output current and the output DC operating voltage to generate an analog signal; digital conversion is performed based on the analog signal to obtain real-time voltage and current values; the real-time voltage and current values ​​are multiplied to generate the actual output power; a preset target power value is read, and the actual output power is compared with the preset target power value to obtain the power deviation; the microcontroller is used to perform closed-loop control adjustment of the magnetron sputtering power supply according to the power deviation, and a duty cycle adjustment signal is generated for continuous drive adjustment.

[0012] Optionally, a deviation interval division table is constructed, and the power deviation is analyzed based on the deviation interval division table to divide multiple value intervals; the power deviation is compared and matched with the multiple value intervals to determine the target falling interval; adjustment calculations are performed based on the target falling interval to obtain the target proportional adjustment coefficient and the target integral adjustment coefficient; the target proportional adjustment coefficient is multiplied by the power deviation to generate a proportional adjustment component; the integral cumulative value is retrieved, and the proportional adjustment component is added to the integral cumulative value to generate an integral adjustment component; the integral adjustment component is added to the proportional adjustment component to generate a duty cycle adjustment signal.

[0013] A second aspect of this application provides a microcontroller-based automatic control system for a magnetron sputtering power supply. The microcontroller-based automatic control system includes: a voltage processing module for acquiring a target voltage through a three-phase four-wire input terminal, filtering the target voltage, and generating a first DC voltage; a voltage conversion module for converting the first DC voltage to determine a second DC voltage, modulating the second DC voltage, and applying it to the primary winding of a switching transformer; a voltage output module for controlling the primary winding of the switching transformer by using a pulse width modulation signal output by the microcontroller to achieve push-pull switching, thereby obtaining an output DC operating voltage; and a control and adjustment module for real-time acquisition of the output current and its combination with the output DC operating voltage to perform closed-loop control and adjustment of the magnetron sputtering power supply.

[0014] One or more technical solutions provided in this application have at least the following technical effects or advantages:

[0015] The method provided in this application obtains a target voltage through a three-phase four-wire input terminal, filters the target voltage to generate a first DC voltage, converts the first DC voltage to determine a second DC voltage, modulates the second DC voltage, and applies it to the primary winding of a switching transformer. A microcontroller outputs a pulse width modulation signal to control the primary winding of the switching transformer via push-pull switching, thereby obtaining an output DC operating voltage. Real-time acquisition of the output current combined with the output DC operating voltage enables closed-loop control and regulation of the magnetron sputtering power supply. This achieves the technical effect of real-time tracking and stable regulation of output power through three-phase rectification, filtering, and push-pull PWM closed-loop control, thus improving the stability of the power supply output.

[0016] The above description is merely an overview of the technical solution of this application. To better understand the technical means of this application and to facilitate its implementation according to the description, and to make the above and other objects, features, and advantages of this application more apparent, specific embodiments of this application are described below. It should be understood that the content described in this section is not intended to identify key or important features of the embodiments of this application, nor is it intended to limit the scope of this application. Other features of this application will become readily apparent through the following description. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0018] Figure 1 A flowchart illustrating the automatic control method for magnetron sputtering power supply based on a microcontroller provided in this application.

[0019] Figure 2 A schematic diagram of the structure of the microcontroller-based automatic control system for magnetron sputtering power supply provided in this application.

[0020] Explanation of reference numerals in the attached diagram: Voltage processing module 11, voltage conversion module 12, voltage output module 13, control and regulation module 14. Detailed Implementation

[0021] This application provides a microcontroller-based automatic control method and system for magnetron sputtering power supplies. It addresses the technical problem that existing magnetron sputtering power supplies often employ open-loop or constant-voltage control methods, resulting in poor real-time and accurate tracking of output power as process variations occur, leading to low control precision. The method achieves real-time tracking and stable adjustment of output power through three-phase rectification and filtering combined with push-pull PWM closed-loop control, thereby improving the stability of the power supply output.

[0022] The technical solutions of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. It should be understood that the present invention is not limited to the exemplary embodiments described herein. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. It should also be noted that, for ease of description, only the parts related to the present invention are shown in the accompanying drawings, not all of them.

[0023] Example 1, as Figure 1 As shown, this application provides an automatic control method for a magnetron sputtering power supply based on a microcontroller. The automatic control method for a magnetron sputtering power supply based on a microcontroller includes:

[0024] The target voltage is obtained through the three-phase four-wire input terminal, and the target voltage is filtered to generate the first DC voltage.

[0025] Furthermore, the target voltage is obtained through the three-phase four-wire input terminal, and the target voltage is filtered to generate a first DC voltage. The method includes: performing multi-stage EMI filtering based on the target voltage to generate an AC voltage; loading the AC voltage onto a three-phase full-bridge rectifier to generate a three-phase AC waveform; performing full-wave rectification on the three-phase AC waveform to output a pulsating DC voltage; performing capacitor energy storage filtering based on the pulsating DC voltage; and performing common-mode inductor high-frequency noise suppression based on the filtering result to generate the first DC voltage.

[0026] Specifically, the three-phase four-wire input terminal refers to the three-phase AC input interface connected to the industrial power supply system, including the U-phase, V-phase, W-phase, and neutral line N, used to receive external industrial AC power. The target voltage is obtained through the three-phase four-wire input terminal, preferably a three-phase 220V line voltage AC input with an input frequency of 50Hz or 60Hz. The obtained target voltage undergoes multi-stage EMI filtering. EMI filtering refers to electromagnetic interference filtering, used to suppress conducted high-frequency noise in the input power grid and interference signals propagating back to the power grid from the high-frequency switching action within the power supply. The multi-stage EMI filtering circuit includes a common-mode inductor, an X capacitor, a Y capacitor, and a differential-mode filter network. The common-mode inductor suppresses high-frequency common-mode noise propagating in the same direction in the U, V, and W phase lines; the X capacitor is connected across the phase lines to filter out differential-mode interference; and the Y capacitor is connected between the phase line and the ground terminal to discharge high-frequency common-mode noise. The target voltage enters the EMI filter module after passing through a surge absorption network. The surge absorption network includes a varistor and an NTC thermistor. The varistor absorbs input overvoltage spikes, while the NTC thermistor limits the charging surge current of the filter capacitor at power-on. After multiple stages of EMI filtering, high-frequency spikes, harmonic interference, and transient noise in the input AC waveform are weakened, thereby generating an AC voltage that meets the requirements of the subsequent rectification stage.

[0027] An AC voltage is applied to a three-phase full-bridge rectifier, which is a bridge rectifier structure composed of six rectifier diodes. Each pair of diodes forms a conduction loop, and the unidirectional conductivity of the diodes converts the three-phase AC to DC, generating a three-phase AC waveform. This three-phase AC waveform is then fully rectified. At any given time, the phase with the highest potential is turned on through the upper bridge arm diode, and the phase with the lowest potential is turned on through the lower bridge arm diode, thus creating a continuously varying pulsating DC voltage at the rectifier bridge output. Because the three-phase rectification is a six-pulse rectification structure, the output ripple frequency is six times the input AC frequency, effectively reducing the filtering pressure on subsequent stages.

[0028] A capacitor is used to filter the pulsating DC voltage. A large-capacity filter capacitor C1 is connected in parallel at the output of the rectifier bridge. The charging and discharging characteristics of the capacitor are used to smooth the pulsating DC. When the rectified output voltage is higher than the capacitor terminal voltage, the filter capacitor charges and stores energy. When the rectified output voltage drops, the filter capacitor releases energy to maintain output stability, thereby reducing DC ripple. The filter capacitor is preferably a large-capacity electrolytic capacitor with a withstand voltage of 450V or higher.

[0029] After capacitor energy storage and filtering, common-mode inductor high-frequency noise suppression is performed based on the filtering results. Common-mode inductor high-frequency noise suppression utilizes the high impedance characteristic of the common-mode inductor to suppress high-frequency switching noise. This is achieved by connecting a common-mode inductor in series on the bus output side, thereby suppressing high-frequency ripple and spike signals and generating the first DC voltage. For example, with a three-phase input line voltage of 220V and a frequency of 50Hz, the input first passes through an input protection module consisting of a 20D561 varistor, a 10D-11 NTC thermistor, and a two-stage EMI filter network. The common-mode inductor has an inductance of 5mH, the X capacitor has a capacitance of 0.47μF, and the Y capacitor has a capacitance of 2200pF. The EMI-filtered three-phase AC power is then input to a three-phase full-bridge rectifier consisting of six MUR3060 rectifier diodes. After rectification, the output voltage is a pulsating DC voltage with a peak value of approximately 300V. Subsequently, an electrolytic capacitor C1 with a capacitance of 470μF and a withstand voltage of 450V is used for energy storage and filtering, reducing the ripple voltage from approximately 35V to approximately 8V. Finally, a common-mode inductor with an inductance of 3mH is used to suppress high-frequency noise, ultimately obtaining a first DC voltage of approximately 300V with a ripple of less than 5%, which is then used as the input DC bus of the subsequent MOS push-pull high-frequency converter circuit.

[0030] By performing EMI suppression, full-bridge rectification, energy storage filtering, and high-frequency noise isolation on the industrial three-phase AC input, a stable, low-ripple, and highly anti-interference DC bus voltage is generated, providing a stable energy foundation for the microcontroller-controlled high-frequency push-pull converter. This avoids the impact of input grid fluctuations, high-frequency noise, and surge impacts on the output stability of the magnetron sputtering power supply, thereby improving the reliability and control accuracy of the magnetron sputtering power supply.

[0031] Based on the first DC voltage, a second DC voltage is determined, the second DC voltage is modulated, and applied to the primary winding of the switching transformer.

[0032] Furthermore, the method for determining the second DC voltage based on the first DC voltage includes: connecting the first DC voltage to the input terminal of a push-pull topology, connecting the control terminals of multiple power transistors to a microcontroller, and generating a pulse width modulation (PWM) signal by performing two-way phase complementarity according to a preset switching frequency; alternately driving the power transistors of the push-pull topology to conduct based on the PWM signal, wherein the power transistors of the push-pull topology include a first power transistor and a second power transistor; when the first power transistor is turned on, a current loop is generated, and the first DC voltage is modulated based on the current loop to generate the second DC voltage; when the second power transistor is turned on, a reverse pulse voltage is generated, and the first DC voltage is modulated based on the reverse pulse voltage to generate the second DC voltage.

[0033] Specifically, a first DC voltage is connected to the input terminal of a push-pull topology. This push-pull topology is a high-frequency inverter structure formed by the alternating conduction of multiple power switching devices to create bidirectional magnetic flux excitation. Its main function is to convert the stable DC bus voltage into a high-frequency pulse voltage. Preferably, the push-pull topology includes a first power transistor and a second power transistor, both of which are MOSFET power devices. Their drains are connected to the high-voltage DC bus, their sources are connected to the power circuit, and their gates are connected to the PWM drive terminal output by the microcontroller. The control terminals of the multiple power transistors are connected to the microcontroller. The microcontroller performs two-way phase complementarity according to a preset switching frequency, preferably 20kHz~60kHz, to generate a pulse width modulation signal. The pulse width modulation signal, or PWM signal, is a high-frequency switching control signal that achieves energy control by adjusting the ratio of high and low level durations. Phase complementarity means that the conduction sequence of the two PWM signals is opposite; that is, when one is on, the other is off, to avoid the two power transistors conducting simultaneously and forming a shoot-through short circuit. The microcontroller can also add a dead time between the two PWM channels. The dead time refers to the short time reserved for simultaneous shutdown during the switching process of the two power transistors, such as 0.5μs~3μs, to prevent the bridge arm from short-circuiting due to the turn-off delay of the MOSFET.

[0034] The push-pull topology power transistors are alternately driven to conduct based on the pulse width modulation signal: when the first PWM signal is active, the first power transistor is turned on, and the first DC voltage is applied to one side of the primary winding of the switching transformer through the first power transistor, forming a current loop in the first direction. At this time, the current flows from the positive terminal of the DC bus to the first power transistor, then flows through the primary winding of the switching transformer and returns to the negative terminal of the bus, thereby forming a positive magnetic flux inside the transformer core. Since the MOS power transistor operates in a high-frequency switching state, this conduction process will cut the originally continuous and stable first DC voltage into a high-frequency positive pulse voltage, and apply it to the primary winding of the switching transformer in pulse form, thereby generating a corresponding second DC voltage.

[0035] When the second PWM signal is active, the second power transistor turns on, and the original current loop switches to the other power branch, forming a current flow path opposite to the first direction. At this time, a reverse magnetic flux is formed in the primary winding of the switching transformer, and the first DC voltage is converted into a reverse pulse voltage under the high-frequency conduction of the second power transistor. Through the alternating conduction of the first and second power transistors, a periodically alternating high-frequency pulse voltage parameter, i.e., the second DC voltage, is formed across the primary winding of the switching transformer. The voltage waveform of the second DC voltage has been high-frequency modulated by the PWM, possessing high-frequency alternating characteristics, which can form a continuously changing magnetic field in the switching transformer, realizing high-frequency energy coupling and transmission.

[0036] The microcontroller modulates the second DC voltage based on the output voltage, current, and power deviation results collected from the feedback from the downstream stage. It adjusts the PWM duty cycle or conduction time in real time to dynamically control the energy of the second DC voltage, applying it to the primary winding of the switching transformer to achieve stable regulation of the magnetron sputtering output power. The microcontroller pre-stores a target power value, which is converted from the magnetron sputtering setting parameters and written into the control register during the initialization phase as a reference value for closed-loop control. When the actual output power is lower than the target power, the microcontroller increases the PWM duty cycle or extends the power transistor conduction time, allowing more energy from the first DC voltage to be applied to the primary winding of the switching transformer in the form of high-frequency pulses, thereby increasing the pulse energy corresponding to the second DC voltage. When the actual output power is higher than the target power, the microcontroller decreases the PWM duty cycle or shortens the conduction time to reduce the energy input to the primary winding of the transformer.

[0037] The push-pull power transistors are driven alternately at high frequency by complementary PWM signals output from the microcontroller, converting the high-voltage DC bus into adjustable high-frequency pulse energy, which is then applied to the primary winding of the switching transformer, thereby realizing the conversion of DC energy into high-frequency magnetic field energy. Simultaneously, through PWM duty cycle modulation, the amount of energy entering the transformer can be adjusted in real time, enabling the magnetron sputtering power supply to dynamically stabilize its output power according to load changes, improving response speed and closed-loop control accuracy.

[0038] The primary winding of the switching transformer is controlled by a push-pull switch using a pulse width modulation signal output by a microcontroller to obtain the output DC operating voltage.

[0039] Furthermore, the primary winding of the switching transformer is controlled by a microcontroller to achieve push-pull switching, thereby obtaining an output DC operating voltage. The method includes: extracting multiple pulse-width modulation (PWM) signals from the microcontroller; applying these signals to multiple power transistors in a push-pull power converter circuit for alternating conduction control to generate a first control result; applying these signals to the same power transistors for alternating deactivation control to generate a second control result; performing voltage modulation based on the first and second control results to generate high-frequency alternating pulse voltage parameters; applying these parameters to the primary winding of the switching transformer for secondary induction to generate high-frequency alternating voltage parameters; and performing diode rectification based on these parameters to obtain the output DC operating voltage.

[0040] Furthermore, the method involves applying the multi-path pulse width modulation (PWM) signals to multiple power transistors in a push-pull power converter circuit for alternating conduction control to generate a first control result. This includes: analyzing the multi-path PWM signals to extract a first PWM signal and a second PWM signal; the push-pull power converter circuit includes a first power transistor and a second power transistor; connecting the first PWM signal to the gate drive terminal of the first power transistor in the push-pull power converter circuit, and connecting the second PWM signal to the gate drive terminal of the second power transistor; when the first PWM signal is at an active level, the first power transistor is turned on, generating a positive magnetic flux, and this positive magnetic flux is added as a positive conduction record to the first control result; when the second PWM signal is at an active level, the second power transistor is turned on, generating a reverse magnetic flux, and this reverse magnetic flux is added as a reverse conduction record to the first control result.

[0041] Specifically, the process involves extracting multiple pulse width modulation (PWM) signals from the microcontroller. These PWM signals are digital control signals generated by the microcontroller's internal timer module based on preset switching frequency and duty cycle parameters. They are used to control the on and off time ratios of power switching devices, thereby achieving energy regulation. The extracted PWM signals are then logically analyzed to separate a first PWM signal and a second PWM signal. These PWM signals originate from the outputs of two complementary timer channels within the microcontroller. The first PWM signal controls the gate drive of a first power transistor, and the second PWM signal controls the gate drive of a second power transistor. Both the first and second power transistors are MOSFET devices, and their gates are connected to the microcontroller's PWM output via a drive circuit, such as an isolated gate driver chip, to achieve isolated driving of the high-voltage power devices by the low-voltage control signal.

[0042] When the first PWM signal is validly high, the first power transistor is turned on, and the second power transistor remains off. At this time, the first DC bus voltage is applied to the primary winding of the switching transformer through the first power transistor, forming a unidirectional current loop. This causes the primary winding of the switching transformer to generate a positive magnetic flux, and the positive magnetic flux is recorded as a positive conduction and added to the first control result. When the second PWM signal is validly high, the second power transistor is turned on, and the first power transistor is turned off. The current direction is reversed, forming a reverse current loop. This causes the primary winding of the switching transformer to generate a reverse magnetic flux, which is also written to the first control result to fully describe the magnetic flux change state within one switching cycle.

[0043] Multiple power transistors in a push-pull power converter circuit are alternately turned off by applying multi-path pulse width modulation (PWM) signals. This alternating turn-off control refers to using complementary PWM signals and a dead-time control mechanism during the power transistor switching process. This ensures that the currently conducting power transistor first enters a non-driven state before turning off, delaying the turn-on of the other power transistor. This avoids shoot-through between the upper and lower bridge arms and reduces switching losses. The dead time is preferably set to 0.5μs~3μs to ensure that the power transistor completely exits the conducting state before entering the conducting state of the opposite power transistor. By inserting dead-time control logic between the two PWM switching paths and controlling the power transistor turn-off process, a second control result is generated.

[0044] After obtaining the first and second control results, the two types of control information are fused to form a complete power switch state matrix. Based on the power switch state matrix, the duty cycle D is obtained by calculating the ratio of the actual on-time Ton of the first and second power transistors to the total cycle time T in each PWM switching cycle. Simultaneously, the effective on-time is corrected by combining the dead time Td, and the flux change rate is calculated based on the change in transformer primary inductance current ΔI / Δt. Thus, the on-duty cycle, turn-off delay, and flux slope are calculated as equivalent voltage coefficients. The equivalent high-frequency alternating voltage parameter Veq = Vdc × D × f(Td, ΔΦ) obtained by multiplying it with the DC bus voltage Vdc is obtained. ΔΦ refers to the change in magnetic flux generated by the primary core of the switching transformer in one PWM switching cycle, that is, the change in magnetic flux formed by the integration of the instantaneous voltage applied across the primary winding. It is used to characterize the actual magnetization degree of the core from the initial magnetic state to the final magnetic state in this cycle, reflecting the intensity and efficiency of the conversion of electrical energy to magnetic energy. The high-frequency alternating voltage parameter is used to characterize the instantaneous energy level actually applied to the primary winding of the switching transformer.

[0045] The high-frequency alternating pulse voltage parameters are applied to the primary winding of the switching transformer. This is achieved through a series circuit between the MOS power transistor and the primary winding, creating an alternating current in the primary winding. This generates an alternating magnetic flux in the iron core, producing the high-frequency alternating voltage parameters. These parameters are then rectified using diodes. Specifically, the high-frequency alternating voltage parameters are input into a full-wave rectifier circuit composed of fast recovery rectifier diodes or Schottky diodes. Utilizing the unidirectional conduction characteristics of the diodes, full-wave rectification yields a stable DC operating voltage.

[0046] By generating multiple complementary PWM control signals through a microcontroller, the push-pull power transistors can be precisely switched on and off alternately, improving the stability of the power output. At the same time, it provides a continuous and controllable DC power supply for the magnetron sputtering load, improving the consistency of the sputtering process.

[0047] The output current is collected in real time and combined with the output DC operating voltage to perform closed-loop control and regulation of the magnetron sputtering power supply.

[0048] Furthermore, the closed-loop control adjustment of the magnetron sputtering power supply is performed by real-time acquisition of the output current and the output DC operating voltage. The method includes: performing signal analysis based on the output current and the output DC operating voltage to generate an analog signal; performing digital conversion based on the analog signal to obtain real-time voltage and real-time current values; multiplying the real-time voltage and real-time current values ​​to generate the actual output power; reading a preset target power value and comparing the actual output power with the preset target power value to obtain the power deviation; and performing closed-loop control adjustment of the magnetron sputtering power supply by the microcontroller based on the power deviation to generate a duty cycle adjustment signal for continuous drive adjustment.

[0049] Specifically, the output current is acquired through a series sampling resistor or a Hall current sensor. The output current and the output DC operating voltage are input to a signal conditioning circuit for signal analysis. The signal conditioning circuit consists of an isolation operational amplifier, an RC filter network, and an anti-aliasing filter, used to remove high-frequency switching noise and common-mode interference, thereby generating a stable analog electrical signal. The conditioned analog signal is then input to the microcontroller's internal ADC module for digital conversion. The ADC conversion accuracy is preferably 12-bit or 16-bit, and its sampling frequency is synchronized with or multiplied by the PWM switching frequency to ensure accurate capture of high-frequency dynamic changes.

[0050] Real-time voltage and current values ​​are obtained through ADC conversion. These values ​​are then multiplied to obtain the actual output power, which characterizes the true energy consumption level of the current magnetron sputtering load. Simultaneously, the microcontroller pre-stores target power values ​​issued by the machine's process parameters. The actual output power is compared with these preset target power values, and the absolute value is taken to obtain the power deviation, reflecting the degree of deviation between the current system energy supply and process requirements.

[0051] The microcontroller performs closed-loop control adjustment of the magnetron sputtering power supply based on the power deviation, generating a duty cycle adjustment signal that acts on the PWM generation module, thereby adjusting the on-time ratio of the push-pull power transistor in real time, causing the energy entering the primary winding of the switching transformer to change accordingly, and realizing continuous drive adjustment of the second DC voltage and output power.

[0052] By sampling the output voltage and current in real time and calculating the actual output power, the difference between the actual power and the target power is compared to form a closed-loop control quantity. This enables the microcontroller to dynamically adjust the PWM duty cycle, thereby achieving precise control of the input energy of the push-pull converter stage. Ultimately, this ensures the stability of the output power and the consistency of the process during magnetron sputtering, and improves the stability of plasma discharge and the uniformity of sputtering deposition.

[0053] Furthermore, based on the power deviation, the microcontroller performs closed-loop control adjustment of the magnetron sputtering power supply to generate a duty cycle adjustment signal. The method includes: constructing a deviation interval division table; analyzing the power deviation value based on the deviation interval division table to divide it into multiple value intervals; comparing the power deviation value with the multiple value intervals to determine the target falling interval; performing adjustment calculations based on the target falling interval to obtain a target proportional adjustment coefficient and a target integral adjustment coefficient; multiplying the target proportional adjustment coefficient by the power deviation value to generate a proportional adjustment component; retrieving the integral cumulative value; adding the proportional adjustment component to the integral cumulative value to generate an integral adjustment component; and adding the integral adjustment component to the proportional adjustment component to generate a duty cycle adjustment signal.

[0054] Specifically, a deviation interval division table is constructed. This table is a segmented control rule table pre-set according to the power dynamic response characteristics of the magnetron sputtering process. The criteria include the rated power range of the equipment, the nonlinear characteristics of the plasma load, and the system response speed requirements. The power deviation is divided into multiple value intervals, for example: power deviation ≤ 100W is a small deviation interval, 100W < power deviation ≤ 300W is a medium deviation interval, and power deviation > 300W is a large deviation interval. The real-time calculated power deviation is compared and matched with these multiple value intervals, and the target interval of the current deviation is determined through interval judgment logic.

[0055] After determining that the target falls within the specified range, the microcontroller calls preset control parameters based on that range to obtain the target proportional control coefficient and the target integral control coefficient. The proportional control coefficient reflects the immediate impact of the current deviation on the output adjustment, while the integral control coefficient eliminates long-term steady-state errors. Parameters are configured according to different magnetron sputtering processes, such as metal sputtering and oxide sputtering, and stored in a deviation range table. For example, in the small deviation range, the system is near steady-state operation. The control objective is primarily to suppress minor fluctuations and improve output stability. Therefore, the proportional control coefficient Kp is set to 0.02, and the integral control coefficient Ki is set to 0.002, making the system response smoother and avoiding output oscillations caused by over-adjustment. Simultaneously, a small integral gain is used to slowly eliminate minor steady-state errors. In the medium deviation range, the system is in a moderate dynamic adjustment phase, requiring a balance between response speed and stability. Therefore, the proportional control coefficient Kp is set to 0.05, and the integral control coefficient Ki is set to 0.01. Within this range, the proportional action is used to quickly correct power deviations, while the integral action is used to gradually eliminate persistent deviations, allowing the output power to quickly approach the target value while maintaining a small overshoot. For large deviation ranges, the system is in a state of obvious mismatch or process change, such as plasma ignition or load change. At this time, it is necessary to enhance the system response capability. Therefore, the proportional gain Kp is set to 0.1 and the integral gain Ki is set to 0.02. The larger proportional gain is used to quickly increase or decrease the PWM duty cycle to achieve fast power tracking. At the same time, the integral gain is appropriately increased to accelerate the elimination of the cumulative error caused by large deviations and enable the system to recover to the target power range as soon as possible.

[0056] The target proportional adjustment coefficient is multiplied by the power deviation to generate a proportional adjustment component, which is used to quickly respond to changes in the current power deviation. Simultaneously, the microcontroller retrieves the integral cumulative value, which is the cumulative integral result of the deviation over historical control cycles. This integral cumulative value is updated by periodically summing the product of the target proportional adjustment coefficient and the power deviation. The proportional adjustment component and the integral cumulative value are then summed to generate a duty cycle adjustment signal. This signal is input to the PWM generator module as a control reference for adjusting the conduction time of the push-pull power transistor, thereby achieving dynamic adjustment of the second DC voltage energy input. The duty cycle adjustment signal is a digital control quantity for the energy injection ratio within the switching cycle, directly determining the energy transmission intensity of the transformer's primary winding, and realizing closed-loop stable control of the magnetron sputtering power supply's output power.

[0057] By introducing a segmented deviation control and a proportional-integral parameter adaptive adjustment mechanism, the microcontroller can dynamically select the control gain according to different power deviation ranges. Through proportional and integral dual-channel adjustment, a balance between fast response and steady-state accuracy is achieved, thereby improving the stability and anti-disturbance capability of the magnetron sputtering power supply under nonlinear plasma load conditions.

[0058] In summary, the microcontroller-based automatic control method for magnetron sputtering power supplies provided in this application has the following technical effects: A stable DC bus voltage is obtained through three-phase four-wire input rectification and filtering. Combined with a microcontroller-driven push-pull high-frequency converter structure, a power closed-loop control mechanism based on real-time voltage and current sampling is introduced at the output end. This enables real-time calculation and dynamic adjustment of the output power, allowing for timely adjustment of the PWM duty cycle according to load changes, ensuring stable output power tracking of the target setpoint. This achieves the technical effects of realizing precise real-time closed-loop control of output power, improving the dynamic response capability of the power supply, and enhancing the stability and consistency of the magnetron sputtering process.

[0059] Example 2 is based on the same inventive concept as the microcontroller-based automatic control method for magnetron sputtering power supplies in the previous examples, such as... Figure 2 As shown, this application provides a microcontroller-based automatic control system for magnetron sputtering power supplies, wherein the microcontroller-based automatic control system for magnetron sputtering power supplies includes:

[0060] The voltage processing module 11 is used to acquire the target voltage through the three-phase four-wire input terminal, filter the target voltage, and generate a first DC voltage; the voltage conversion module 12 is used to convert based on the first DC voltage, determine a second DC voltage, modulate the second DC voltage, and apply it to the primary winding of the switching transformer; the voltage output module 13 is used to control the primary winding of the switching transformer by outputting a pulse width modulation signal from a microcontroller to obtain an output DC operating voltage; the control and adjustment module 14 is used to collect the output current in real time and combine it with the output DC operating voltage to perform closed-loop control and adjustment of the magnetron sputtering power supply.

[0061] Furthermore, the voltage processing module 11 is also used to: perform multi-stage EMI filtering based on the target voltage to generate an AC voltage; load the AC voltage onto a three-phase full-bridge rectifier bridge to generate a three-phase AC waveform; perform full-wave rectification on the three-phase AC waveform to output a pulsating DC voltage; perform capacitor energy storage filtering based on the pulsating DC voltage; and perform common-mode inductor high-frequency noise suppression according to the filtering result to generate a first DC voltage.

[0062] Furthermore, the voltage conversion module 12 is also used to: connect the first DC voltage to the input terminal of the push-pull topology, connect the control terminals of multiple power transistors to a microcontroller, and generate a pulse width modulation signal by performing two-way phase complementarity according to a preset switching frequency; alternately drive the power transistors of the push-pull topology to conduct based on the pulse width modulation signal, wherein the power transistors of the push-pull topology include a first power transistor and a second power transistor; when the first power transistor is turned on, a current loop is generated, and the first DC voltage is modulated based on the current loop to generate the second DC voltage; when the second power transistor is turned on, a reverse pulse voltage is generated, and the first DC voltage is modulated based on the reverse pulse voltage to generate the second DC voltage.

[0063] Furthermore, the voltage output module 13 is also used to: extract the multi-channel pulse width modulation signals from the microcontroller; apply the multi-channel pulse width modulation signals to multiple power transistors in the push-pull power converter circuit for alternating conduction control to generate a first control result; apply the multi-channel pulse width modulation signals to multiple power transistors in the push-pull power converter circuit for alternating turn-off control to generate a second control result; perform voltage modulation based on the first control result and the second control result to generate high-frequency alternating pulse voltage parameters; apply the high-frequency alternating pulse voltage parameters to the primary winding of the switching transformer for secondary induction to generate high-frequency alternating voltage parameters; and perform diode rectification based on the high-frequency alternating voltage parameters to obtain an output DC operating voltage.

[0064] Furthermore, the voltage output module 13 is also used for: parsing the multi-channel pulse width modulation signals to extract the first pulse width modulation signal and the second pulse width modulation signal; the push-pull power conversion circuit includes a first power transistor and a second power transistor; connecting the first pulse width modulation signal to the gate driving terminal of the first power transistor in the push-pull power conversion circuit, and connecting the second pulse width modulation signal to the gate driving terminal of the second power transistor; when the first pulse width modulation signal is at an effective level, the first power transistor is turned on to generate a positive magnetic flux, and the positive magnetic flux is added to the first control result as a positive conduction record; when the second pulse width modulation signal is at an effective level, the second power transistor is turned on to generate a reverse magnetic flux, and the reverse magnetic flux is added to the first control result as a reverse conduction record.

[0065] Furthermore, the control and adjustment module 14 is also used for: performing signal analysis based on the output current and the output DC operating voltage to generate an analog signal; performing digital conversion based on the analog signal to obtain real-time voltage and real-time current values; multiplying the real-time voltage and real-time current values ​​to generate the actual output power; reading a preset target power value, comparing the actual output power with the preset target power value to obtain a power deviation; and performing closed-loop control adjustment of the magnetron sputtering power supply on the microcontroller according to the power deviation to generate a duty cycle adjustment signal for continuous drive adjustment.

[0066] Furthermore, the control and adjustment module 14 is also used to: construct a deviation interval division table; analyze the power deviation based on the deviation interval division table to divide multiple value intervals; compare the power deviation with the multiple value intervals to determine the target falling interval; perform adjustment calculations based on the target falling interval to obtain a target proportional adjustment coefficient and a target integral adjustment coefficient; multiply the target proportional adjustment coefficient with the power deviation to generate a proportional adjustment component; retrieve the integral cumulative value; add the proportional adjustment component to the integral cumulative value to generate an integral adjustment component; and add the integral adjustment component to the proportional adjustment component to generate a duty cycle adjustment signal.

[0067] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The microcontroller-based automatic control method and specific examples of the magnetron sputtering power supply in the first embodiment described above are also applicable to the microcontroller-based automatic control system of the magnetron sputtering power supply in this embodiment. Through the foregoing detailed description of the microcontroller-based automatic control method of the magnetron sputtering power supply, those skilled in the art can clearly understand the microcontroller-based automatic control system of the magnetron sputtering power supply in this embodiment. Therefore, for the sake of brevity, it will not be described in detail here.

[0068] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0069] Obviously, those skilled in the art can make several improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of this application.

Claims

1. A microcontroller-based automatic control method for magnetron sputtering power supplies, characterized in that, The method includes: The target voltage is obtained through the three-phase four-wire input terminal, and the target voltage is filtered to generate the first DC voltage; Based on the first DC voltage, a second DC voltage is determined, and the second DC voltage is modulated and applied to the primary winding of the switching transformer; The primary winding of the switching transformer is controlled by a push-pull switching signal output by a microcontroller to obtain the output DC working voltage. The output current is collected in real time and combined with the output DC operating voltage to perform closed-loop control and regulation of the magnetron sputtering power supply.

2. The automatic control method for magnetron sputtering power supply based on a single-chip microcomputer as described in claim 1, characterized in that, The method involves obtaining a target voltage through a three-phase four-wire input terminal, filtering the target voltage, and generating a first DC voltage. Multi-stage EMI filtering is performed based on the target voltage to generate an AC voltage; The AC voltage is applied to the three-phase full-bridge rectifier bridge to generate a three-phase AC waveform; The three-phase AC waveform is rectified by full-wave rectification to output a pulsating DC voltage; Based on the pulsating DC voltage, capacitor energy storage and filtering are performed, and common-mode inductor high-frequency noise suppression is performed according to the filtering result to generate the first DC voltage.

3. The automatic control method for magnetron sputtering power supply based on a single-chip microcomputer as described in claim 1, characterized in that, The method for determining a second DC voltage based on the first DC voltage includes: The first DC voltage is connected to the input terminal of the push-pull topology, and the control terminals of multiple power transistors are connected to the microcontroller. The microcontroller performs two-way phase complementarity according to a preset switching frequency to generate a pulse width modulation signal. The power transistors of the push-pull topology are alternately driven and turned on based on the pulse width modulation signal. The power transistors of the push-pull topology include a first power transistor and a second power transistor. When the first power transistor is turned on, a current loop is generated. Based on the current loop, a positive pulse voltage is converted to modulate the first DC voltage to generate the second DC voltage. When the second power transistor is turned on, a reverse pulse voltage is generated. The first DC voltage is modulated based on the reverse pulse voltage to generate the second DC voltage.

4. The automatic control method for magnetron sputtering power supply based on a single-chip microcomputer as described in claim 1, characterized in that, The primary winding of the switching transformer is controlled by a microcontroller outputting a pulse width modulation signal to achieve push-pull switching, thereby obtaining the output DC operating voltage. The method includes: Extract the multi-channel pulse width modulation signal from the microcontroller, apply the multi-channel pulse width modulation signal to multiple power transistors in the push-pull power conversion circuit for alternating conduction control, and generate the first control result; The multi-path pulse width modulation signal is applied to multiple power transistors in the push-pull power conversion circuit for alternating turn-off control, generating a second control result; Based on the first control result and the second control result, voltage modulation is performed to generate high-frequency alternating pulse voltage parameters. The high-frequency alternating pulse voltage parameters are applied to the primary winding of the switching transformer to induce secondary windings and generate high-frequency alternating voltage parameters. Based on the high-frequency alternating voltage parameters, diode rectification is performed to obtain the output DC operating voltage.

5. The automatic control method for magnetron sputtering power supply based on a single-chip microcomputer as described in claim 4, characterized in that, The method involves applying the multi-path pulse width modulation signal to multiple power transistors in a push-pull power converter circuit for alternating conduction control to generate a first control result. Based on the analysis of the multi-channel pulse width modulation signals, the first pulse width modulation signal and the second pulse width modulation signal are extracted; The push-pull power conversion circuit includes a first power transistor and a second power transistor; The first pulse width modulation signal is connected to the gate drive terminal of the first power transistor in the push-pull power converter circuit, and the second pulse width modulation signal is connected to the gate drive terminal of the second power transistor. When the first pulse width modulation signal is at an effective level, the first power transistor is turned on, generating a positive magnetic flux, and the positive magnetic flux is added to the first control result as a positive conduction record. When the second pulse width modulation signal is at an effective level, the second power transistor is turned on, generating a reverse magnetic flux, and the reverse magnetic flux is added to the first control result as a reverse conduction record.

6. The automatic control method for magnetron sputtering power supply based on a single-chip microcomputer as described in claim 1, characterized in that, The method for closed-loop control and regulation of the magnetron sputtering power supply by real-time acquisition of the output current and combination with the output DC operating voltage includes: Based on the output current and the output DC operating voltage, signal analysis is performed to generate an analog signal; Based on the analog signal, digital conversion is performed to obtain real-time voltage and real-time current values; The actual output power is generated by multiplying the real-time voltage value and the real-time current value. Read the preset target power value, compare the actual output power with the preset target power value, and obtain the power deviation. Based on the power deviation, the microcontroller performs closed-loop control adjustment of the magnetron sputtering power supply, generating a duty cycle adjustment signal for continuous drive adjustment.

7. The automatic control method for magnetron sputtering power supply based on a single-chip microcomputer as described in claim 6, characterized in that, The microcontroller performs closed-loop control adjustment of the magnetron sputtering power supply based on the power deviation, generating a duty cycle adjustment signal. The method includes: Construct a deviation interval division table, and analyze the value of power deviation based on the deviation interval division table to divide it into multiple value intervals; The power deviation is compared and matched with the multiple value intervals to determine which interval the target falls into; Based on the target falling interval, adjustment calculations are performed to obtain the target proportional adjustment coefficient and the target integral adjustment coefficient; Multiply the target proportional adjustment coefficient by the power deviation to generate a proportional adjustment component; Retrieve the integral cumulative value, add the proportional adjustment component to the integral cumulative value, and generate the integral adjustment component; The integral adjustment component and the proportional adjustment component are added together to generate a duty cycle adjustment signal.

8. An automatic control system for magnetron sputtering power supply based on a single-chip microcomputer, characterized in that, The steps for implementing the microcontroller-based automatic control method for magnetron sputtering power supplies according to any one of claims 1 to 7, wherein the microcontroller-based automatic control system for magnetron sputtering power supplies comprises: The voltage processing module is used to acquire the target voltage through the three-phase four-wire input terminal, filter the target voltage, and generate a first DC voltage; A voltage conversion module is used to convert based on the first DC voltage, determine a second DC voltage, modulate the second DC voltage, and apply it to the primary winding of the switching transformer; The voltage output module is used to control the primary winding of the switching transformer by outputting a pulse width modulation signal from a microcontroller to achieve push-pull switching, thereby obtaining an output DC operating voltage. The control and adjustment module is used to collect the output current in real time and combine it with the output DC working voltage to perform closed-loop control and adjustment of the magnetron sputtering power supply.

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