A semiconductor liquid source intermediate frequency induction heating double-loop control method and system

Abstract

The application relates to a semiconductor liquid source intermediate frequency induction heating double-loop control method and system, and belongs to the technical field of semiconductor manufacturing configuration equipment. The method comprises the following steps: acquiring an intermediate frequency induction electric frequency, synchronously adjusting a resonance frequency, and providing liquid source heating control basis; constructing a temperature-pressure double-loop feedback curve, dynamically adjusting inverter output power through a proportional integral algorithm, and controlling the amplitude and distribution of the intermediate frequency induction heating current; the differential serial communication protocol is transmitted to a flexible heating coil through a twisted shielded wire and a differential signal interface, an induced eddy current heating liquid source is heated, the temperature of the induced eddy current heat source is controlled based on a fan-free cooling scheme, the cooling intensity is adjusted in association with the intermediate frequency induction electric frequency, and when it is monitored that the liquid source temperature deviates from a preset safe cooling temperature interval, power limitation is executed based on built-in safety interlocking logic when the load impedance is abnormal.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor manufacturing equipment technology, specifically relating to a dual-loop control method and system for semiconductor liquid source medium-frequency induction heating. Background Technology

[0002] In semiconductor manufacturing, thin film deposition, and chemical vapor deposition processes, liquid precursors or reaction liquid sources typically require controlled heating to ensure stable evaporation or transport performance. Existing liquid source heating methods often employ resistance heating, external heating belts, or hot plate heating. While these solutions are relatively simple in structure, they suffer from low heating efficiency, high thermal inertia, localized overheating, and insufficient electromagnetic compatibility in practical applications, making it difficult to meet the demands of high-precision, fast-response, and high-reliability processes.

[0003] In recent years, medium-frequency induction heating has been gradually introduced into the field of liquid source heating due to its advantages such as non-contact heating, fast response speed, and high energy utilization. However, existing medium-frequency induction heating systems mostly focus on power output or single temperature control, lacking comprehensive consideration of changes in liquid source pressure, load impedance, and the coupling relationships of multiple physical quantities during the heating process. When the state of the liquid source changes, it can easily lead to unstable heating power, and even safety hazards such as resonance deviation, overheating, or overpressure.

[0004] Furthermore, existing induction heating systems often employ fixed-frequency or coarse-tuning methods for inverter control, making it difficult to consistently operate at the optimal resonant point under dynamically changing load parameters, thus affecting energy transfer efficiency. Simultaneously, in complex electromagnetic environments, heating control and power signals are susceptible to electromagnetic interference, leading to decreased control accuracy or even system malfunctions.

[0005] In terms of heat dissipation and safety, traditional liquid source heating equipment mostly relies on fans or forced air cooling for heat dissipation, which not only increases mechanical noise and maintenance costs, but also introduces dust and has insufficient reliability. For semiconductor applications with high cleanliness requirements, the above-mentioned heat dissipation methods are difficult to operate stably for a long time. In addition, the safety protection in existing systems is mostly simple over-temperature or over-current protection, lacking a safety interlock mechanism based on multi-parameter collaborative judgment, making it difficult to effectively intervene before anomalies occur.

[0006] Therefore, how to achieve coordinated control of frequency, power, temperature and pressure during liquid source medium-frequency induction heating while ensuring electromagnetic compatibility and system safety, and improve the stability and reliability of the system, remains a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] To address the aforementioned problems in the prior art, this invention provides a dual-loop control method for semiconductor liquid source medium-frequency induction heating.

[0008] The objective of this invention can be achieved through the following technical solutions:

[0009] S1: Obtain the intermediate frequency induced current frequency, control the frequency range of the output intermediate frequency AC power based on the full-bridge insulated inverter topology, and synchronously adjust the resonant frequency through the phase-locked loop so that the inverter output frequency always tracks the load resonant point, providing the basis for liquid source heating control;

[0010] S2: Construct a temperature-pressure dual-loop feedback curve to collect the temperature and pressure signals of the liquid source bottle wall in real time, and compare them with the corresponding target set values ​​to generate temperature deviation signals and pressure deviation signals. Dynamically adjust the inverter output power through the proportional-integral algorithm to control the amplitude and distribution of the medium-frequency induction heating current and generate directional eddy current heating signals.

[0011] S3: Based on the return path formed by the induced current of the directional eddy current heating signal, a closed electromagnetic shielding circuit is constructed, and transmitted to the flexible heating coil through a twisted-pair shielded wire and a differential signal interface via a differential serial communication protocol to induce the eddy current heating liquid source.

[0012] S4: Based on the fanless cooling scheme, the temperature of the induction eddy current heat source is controlled, and the cooling intensity is adjusted by linking the intermediate frequency induction frequency. When the liquid source temperature is detected to deviate from the preset safe cooling temperature range, the power limit is executed based on the built-in safety interlock logic when the load impedance is abnormal.

[0013] Specifically, the method for obtaining the intermediate frequency induced electric frequency is as follows: the equivalent impedance model of the intermediate frequency induction heating load is performed, the resonant frequency range of the load system is calculated, intermediate frequency sweep detection is performed, the inverter output voltage and current signals are collected to calculate the phase difference between the voltage and current, and the actual resonant frequency of the load is determined according to the frequency point with the smallest phase difference or the largest current amplitude. This frequency is used as the initial output frequency to obtain the intermediate frequency induced electric frequency.

[0014] Specifically, the method for controlling the frequency range of the output intermediate frequency AC power of the full-bridge insulated inverter topology is as follows: a target frequency range for the output intermediate frequency AC power of the inverter is preset according to the heating power requirement of the intermediate frequency induction heating load. Within the target frequency range, the drive signal of the full-bridge inverter power switch is frequency modulated to limit the operating frequency of the inverter output AC power to not exceed the upper and lower limits of the target frequency range. The target frequency range is used as the frequency constraint condition of the phase-locked loop. When the load resonant frequency changes, the output frequency of the phase-locked loop is always limited to the target frequency range, thereby controlling the frequency range of the output intermediate frequency AC power.

[0015] Specifically, the method for synchronously adjusting the resonant frequency of the phase-locked loop is as follows: the phase difference between the intermediate frequency AC voltage signal and the intermediate frequency AC current signal output by the full-bridge insulated inverter topology is calculated, the phase difference is used as the phase error signal of the phase-locked loop, and the phase error signal is filtered and fed back through the phase-locked loop to dynamically adjust the resonant frequency of the intermediate frequency AC power output by the inverter.

[0016] Specifically, the method for constructing the temperature-pressure dual-loop feedback curve is as follows: Target temperature and target pressure curves are set according to the characteristics and process requirements of the semiconductor liquid source. The temperature signal of the liquid source bottle wall and the internal pressure signal are filtered and time-aligned, and mapped to the corresponding target positions to detect control deviation values. The control deviation values ​​include temperature control deviation and pressure control deviation. A temperature-pressure dual-loop feedback curve is constructed. When both temperature control deviation and pressure control deviation exist simultaneously, the two control quantities are coordinated according to a preset priority rule to obtain feedback data of the inverter output power.

[0017] Specifically, the method for dynamically adjusting the inverter output power using the proportional-integral algorithm is as follows: the temperature and pressure signals of the liquid source bottle wall are compared with the target set temperature and pressure values ​​to obtain the temperature deviation and pressure deviation values, and then weighted and superimposed according to the preset weight coefficients to obtain the power control comprehensive error signal, which is input to the proportional-integral controller to limit the integral term or perform anti-integral saturation processing to adjust the inverter output power.

[0018] Specifically, the method for generating the directional eddy current heating signal is as follows: according to the inverter output power adjustment command output by the proportional-integral controller, the amplitude of the intermediate frequency induction heating current output by the full-bridge insulated inverter topology is adjusted, and under the condition that the frequency of the intermediate frequency induction heating current is in the load resonance tracking state, the current phase and on / off timing of the induction heating coil are controlled to generate the corresponding directional eddy current heating signal.

[0019] Specifically, the process of transmitting directional eddy current heating signals using the differential serial communication protocol is as follows: the directional eddy current heating signals are differentially encoded so that the same signal is transmitted in the form of a pair of electrical signals with equal amplitude and opposite phase, and the power adjustment parameters in the directional eddy current heating signals are encapsulated according to the frame structure to transmit directional eddy current heating signals under strong electromagnetic interference environment.

[0020] Specifically, the fanless cooling solution includes a gas holder self-circulating gas cooling system and a Peltier solid-state active cooling heat dissipation system;

[0021] The gas holder self-circulating gas cooling system has a built-in spiral guide channel, which allows the gas inside the gas holder to generate natural convection after being heated and circulate along a preset path. It also uses the density difference formed by the temperature gradient inside the gas holder to drive the gas self-circulation flow, transferring heat from the high-temperature area to the gas holder wall or heat dissipation structure, forming a gas holder gas production-heat dissipation cavity-downstream self-circulation loop.

[0022] The Peltier solid-state active cooling and heat dissipation system applies a control current to control the thermal coupling between the cold end and the heat-generating end, actively extracts the heat generated by the heat-generating end, and thermally connects it with the heat dissipation structure, releasing the extracted heat to the external environment to complete active temperature control and heat dissipation.

[0023] Specifically, the method for setting the safe cooling temperature range is as follows: based on the allowable operating temperature range of the liquid source bottle, determine the corresponding minimum safe temperature threshold and maximum safe temperature threshold, and combine the heat dissipation capacity of the gas holder self-circulating gas cooling system and the Peltier solid-state active cooling heat dissipation system under the fanless cooling scheme to modify the minimum safe temperature threshold and maximum safe temperature threshold, and set the safe cooling temperature range.

[0024] Specifically, the method for limiting the execution power using the built-in safety interlock logic is as follows: Based on the impedance state of the intermediate frequency induction heating load and the operating state of the cooling system, it is determined whether there is over-temperature or abnormal load impedance. When any parameter exceeds the corresponding safety threshold, the safety interlock control is triggered, and power limitation is executed according to the level of abnormality. The safety interlock control includes: when a minor abnormality is detected, inverter output power limitation or frequency offset control is executed; when a moderate abnormality is detected, the Peltier solid-state active cooling system is triggered and the output of the directional eddy current heating signal is limited; when a severe abnormality is detected, the full-bridge insulated inverter topology is immediately shut down and the system remains locked until the abnormality is resolved or the system is reset. The interlock state is maintained until the abnormal state is resolved.

[0025] Specifically, a dual-loop control system for semiconductor liquid source medium-frequency induction heating includes:

[0026] Intermediate Frequency Resonance Control Module: Acquires the intermediate frequency induced current frequency, controls the frequency range of the output intermediate frequency AC power based on the full-bridge insulated inverter topology, and synchronously adjusts the resonant frequency through a phase-locked loop to ensure that the inverter output frequency always tracks the load resonant point, providing the basis for liquid source heating control;

[0027] Temperature and pressure dual-loop control module: Constructs a temperature-pressure dual-loop feedback curve to collect the temperature and pressure signals of the liquid source bottle wall in real time, compare them with the corresponding target set values, generate temperature deviation signals and pressure deviation signals, dynamically adjust the inverter output power through proportional-integral algorithm, control the amplitude and distribution of the medium frequency induction heating current, and generate directional eddy current heating signals.

[0028] Differential shielded transmission module: Based on the return path formed by the induced current of the directional eddy current heating signal, a closed electromagnetic shielding circuit is constructed, and the signal is transmitted to the flexible heating coil through a twisted-pair shielded wire and a differential signal interface via a differential serial communication protocol to induce the eddy current heating liquid source;

[0029] Cooling interlock limiting module: Based on the fanless cooling scheme, it controls the temperature of the induced eddy current heat source and adjusts the cooling intensity by linking the intermediate frequency induced electric frequency. When the liquid source temperature deviates from the preset safe cooling temperature range, it performs power limiting based on the built-in safety interlock logic when the load impedance is abnormal.

[0030] The beneficial effects of this invention are as follows:

[0031] This invention proposes a dual-loop control method for semiconductor liquid source medium-frequency induction heating. By coordinating the design of frequency, power and safety control of the medium-frequency induction heating system, it effectively improves the stability, response speed and operational safety of the liquid source heating process.

[0032] By acquiring the intermediate frequency induced current and adjusting the resonant frequency synchronously based on the full-bridge insulated inverter topology and phase-locked loop, the inverter output frequency can track the load resonant point in real time. Even with changes in the liquid source state and load parameters, the energy transmission efficiency remains stable, reducing energy loss and system instability risks caused by resonance offset, and providing a reliable frequency control basis for liquid source heating.

[0033] A temperature-pressure dual-loop feedback control mechanism is constructed, which introduces the liquid source bottle wall temperature and internal pressure signals into the same control framework. The proportional-integral algorithm is used to dynamically adjust the inverter output power, thereby achieving precise control over the amplitude and distribution of the medium-frequency induction heating current. This results in a directional eddy current heating effect, reduces local overheating, and improves the uniformity of liquid source heating and control accuracy.

[0034] The directional eddy current heating signal is ceramic-encapsulated and double-layered copper-shielded, and transmitted to the flexible heating coil via a twisted-pair shielded cable through a differential serial communication protocol. This effectively suppresses electromagnetic interference and improves the signal integrity and reliability of the system in complex electromagnetic environments.

[0035] Furthermore, this invention combines a fanless cooling solution with built-in safety interlock logic to regulate the temperature of the induced eddy current heat source and perform power limiting or protection control under abnormal operating conditions, thereby reducing system operation risks, improving overall safety and long-term operational reliability, and is suitable for semiconductor liquid source heating scenarios with high requirements for cleanliness and stability. Attached Figure Description

[0036] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0037] Figure 1 This is a schematic diagram of the framework of a dual-loop control method for semiconductor liquid source medium-frequency induction heating according to the present invention.

[0038] Figure 2 This is a schematic diagram of the induction heating system of a dual-loop control system for semiconductor liquid source medium-frequency induction heating according to the present invention.

[0039] Figure 3 This is a block diagram of a dual-loop feedback control system for a semiconductor liquid source medium-frequency induction heating dual-loop control system according to the present invention. Detailed Implementation

[0040] To further illustrate the technical means and effects of the present invention in achieving the intended purpose, the following detailed description of the specific implementation methods, structures, features and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.

[0041] Please see Figure 1 A dual-loop control method for semiconductor liquid source medium-frequency induction heating:

[0042] S1: Obtain the intermediate frequency induced current frequency, control the frequency range of the output intermediate frequency AC power based on the full-bridge insulated inverter topology, and synchronously adjust the resonant frequency through the phase-locked loop so that the inverter output frequency always tracks the load resonant point, providing the basis for liquid source heating control;

[0043] S2: Construct a temperature-pressure dual-loop feedback curve to collect the temperature and pressure signals of the liquid source bottle wall in real time, and compare them with the corresponding target set values ​​to generate temperature deviation signals and pressure deviation signals. Dynamically adjust the inverter output power through the proportional-integral algorithm to control the amplitude and distribution of the medium-frequency induction heating current and generate directional eddy current heating signals.

[0044] S3: Based on the return path formed by the induced current of the directional eddy current heating signal, a closed electromagnetic shielding circuit is constructed, and transmitted to the flexible heating coil through a twisted-pair shielded wire and a differential signal interface via a differential serial communication protocol to induce the eddy current heating liquid source.

[0045] S4: Based on the fanless cooling scheme, the temperature of the induction eddy current heat source is controlled, and the cooling intensity is adjusted by linking the intermediate frequency induction frequency. When the liquid source temperature is detected to deviate from the preset safe cooling temperature range, the power limit is executed based on the built-in safety interlock logic when the load impedance is abnormal.

[0046] In this embodiment, the method for obtaining the intermediate frequency induced electric frequency is as follows: the equivalent impedance model of the intermediate frequency induction heating load is performed, the resonant frequency range of the load system is calculated, intermediate frequency sweep detection is performed, the inverter output voltage and current signals are collected to calculate the phase difference between the voltage and current, and the actual resonant frequency of the load is determined according to the frequency point with the smallest phase difference or the largest current amplitude. This frequency is used as the initial output frequency to obtain the intermediate frequency induced electric frequency.

[0047] In this embodiment, the method for controlling the frequency range of the output intermediate frequency AC power of the full-bridge insulated inverter topology is as follows: a target frequency range for the output intermediate frequency AC power of the inverter is preset according to the heating power requirement of the intermediate frequency induction heating load. Within the target frequency range, the drive signal of the full-bridge inverter power switch is frequency modulated to limit the operating frequency of the inverter output AC power to not exceed the upper and lower limits of the target frequency range. The target frequency range is used as the frequency constraint condition of the phase-locked loop. When the load resonant frequency changes, the output frequency of the phase-locked loop is always limited to the target frequency range, thereby controlling the frequency range of the output intermediate frequency AC power.

[0048] In this embodiment, the method for synchronously adjusting the resonant frequency of the phase-locked loop is as follows: the phase difference between the intermediate frequency AC voltage signal and the intermediate frequency AC current signal output by the full-bridge insulated inverter topology is calculated, the phase difference is used as the phase error signal of the phase-locked loop, and the phase error signal is filtered and fed back through the phase-locked loop to dynamically adjust the resonant frequency of the intermediate frequency AC power output by the inverter.

[0049] In this embodiment, the method for constructing the temperature-pressure dual-loop feedback curve is as follows: Target temperature curve and target pressure curve are set according to the characteristics and process requirements of the semiconductor liquid source. The temperature signal of the liquid source bottle wall and the internal pressure signal are filtered and time-aligned, and mapped to the corresponding target positions to detect control deviation values. The control deviation values ​​include temperature control deviation and pressure control deviation. A temperature-pressure dual-loop feedback curve is constructed. When both temperature control deviation and pressure control deviation exist simultaneously, the two control quantities are coordinated according to a preset priority rule to obtain feedback data of the inverter output power.

[0050] In this embodiment, as Figure 2 The system shown uses a power controller as its energy core, outputting 20-50kHz medium-frequency AC power to the induction coil inside the flexible heating blanket; the coil generates an alternating magnetic field, inducing eddy currents inside the cylinder wall to achieve directional heating of the liquid-gas interface; a dual-loop feedback system collects temperature and pressure signals to dynamically adjust power parameters; a fanless cooling module provides long-term heat dissipation for power devices, ensuring stable operation for 24 hours.

[0051] The power controller adopts a full-bridge IGBT inverter topology, with an output intermediate frequency AC power frequency range of 20-50kHz. It achieves automatic resonant frequency tracking through phase-locked loop (PLL) technology to ensure that the system always operates in the optimal energy transmission state when the load impedance changes. It has built-in safety interlock logic for over-temperature, over-voltage, over-current and dry-burn protection, and the abnormal signal response time is ≤0.1ms.

[0052] like Figure 3 The dual-loop feedback control system shown uses an embedded control module with an MCU as its core.

[0053] Temperature feedback monitoring unit: It adopts an array of PT100 platinum resistance sensors. The main sensor is embedded in the low-interference area of ​​the heating blanket. The minimum distance between the sensor and the coil is ≥20mm, so as to achieve accurate acquisition of the cylinder wall temperature.

[0054] Pressure feedback acquisition unit: The pressure sensor is arranged inside the gas outlet flange of the gas cylinder (5-10mm from the outlet end face) and coaxial with the flow channel axis; it adopts anti-condensation encapsulation, temperature resistance range -20℃~120℃, measurement range 0-2.5MPa, accuracy ±0.25% FS, and is fixed by threaded seal to avoid flow field disturbance.

[0055] Coordinated control strategy: Built-in PID control algorithm, signal sampling frequency ≥1kHz; adopts a priority strategy of "temperature safety first, pressure stability as the main focus": if the response time of the temperature over-limit signal (≥80℃±5℃) is ≤0.1ms, the power is immediately cut off; when the temperature is safe, the pressure deviation is the core, and the pressure accuracy is maintained at ±0.02MPa by adjusting the power output power (step size ≤5W).

[0056] The fanless solid-state cooling module and power controller are integrated into a sealed aluminum housing, offering two alternative options:

[0057] Option 1: Gas holder self-circulating gas cooling system: Power devices are bonded to aluminum nitride (AlN) ceramic substrates (thermal conductivity ≥170W / (m·K), thickness 2-3mm), and the substrates are coupled to copper heat dissipation chambers (built-in spiral flow channel: inner diameter 8-12mm, pitch 15-20mm); the heat dissipation chambers are connected to the outlet branch of the gas holder through high-temperature resistant hoses to form a self-circulating loop of "gas holder gas production - heat dissipation chamber - downstream", and the interface adopts V-ring sealing with protection level IP66.

[0058] Option 2: Peltier solid-state active cooling system: Power devices are bonded to multi-stage series Peltier modules (cooling power 50-150W, temperature difference ≥60℃) via thermal pads. The hot end of the module is coupled to an aluminum heat sink array (thickness 1.5-2mm, spacing 8-10mm) via an AlN substrate. An NTC temperature sensor is configured to achieve temperature linkage control. The module is encapsulated with potting compound and has a mechanical life of ≥50,000 hours.

[0059] Both solutions feature standardized installation interfaces, and the housing is die-cast (flatness ≤0.02mm), with an IP66 protection rating, adaptable to different scenario requirements.

[0060] The work process is as follows:

[0061] Installation and Fitting: Secure the flexible heating blanket to the bottom of the gas cylinder using Velcro / clips, and select a fanless cooling solution to assemble the power controller;

[0062] Energy output: The power controller outputs 20-50kHz medium frequency AC power to the coil, which generates an alternating magnetic field, induces eddy currents in the cylinder wall and generates Joule heat, heating the liquid-gas interface to achieve vaporization.

[0063] Dual-loop control: a temperature sensor collects the cylinder wall temperature, and a pressure sensor collects the outlet pressure; power is immediately cut off if the temperature exceeds the limit, and power is adjusted through a PID algorithm to maintain stable pressure when the temperature is safe;

[0064] Long-lasting cooling: The gas holder self-circulation scheme uses vaporized gas for heat dissipation, or the Peltier scheme actively cools to ensure that the temperature of power devices remains stable at 25-60℃.

[0065] The specific implementation process is as follows:

[0066] Taking the vaporization of a typical liquid source in a gas cylinder as an example, a flexible induction heating coil is used to generate eddy currents by being placed against the bottom of the gas cylinder to achieve directional heating. Temperature and pressure signals are fed into the MCU via a dual-loop feedback module, and a PID algorithm is executed to adjust the inverter output power, so that the vaporization process operates in a highly efficient, safe, and controllable manner.

[0067] The flexible induction heating coil's internal structure is integrally molded from silicone, with the heating coil embedded in the middle layer. Its elastic structure ensures it won't deform or warp when fitting gas cylinders with varying curvatures. The temperature sensor is positioned in a low-magnetic-field area and equipped with ceramic and copper shielding to suppress electromagnetic interference.

[0068] The power controller employs an IGBT full-bridge inverter and automatically adjusts the operating frequency via a PLL to match the equivalent resonant point of the coils, improving efficiency and reducing component heat loss. An internally embedded safety interlock can detect abnormalities such as dry burning, overheating, and overcurrent in real time.

[0069] A closed electromagnetic shielding loop is housed within the intermediate-frequency induction heating control unit in a ceramic package. An inner copper shielding layer and an outer copper shielding layer are sequentially arranged on the outside of the ceramic package, forming a double-layer shielding structure. The inner copper shielding layer primarily covers key high-frequency nodes of the driving circuit, used to weaken the electromagnetic radiation generated by the intermediate-frequency induction heating signal in the near-field range. The outer copper shielding layer primarily encapsulates the entire ceramic package, used to suppress electromagnetic energy leakage into the external space.

[0070] The inner copper shielding layer and the outer copper shielding layer are connected to the system shielding ground through a preset conductive structure. The conductive structure includes conductive vias, metal pins or shielding connectors, so that a low-impedance connection path is formed between the double copper shielding layers and the system reference ground, so that the induced current generated by the medium frequency induction heating signal can flow back to the system shielding ground through the shielding layer, thereby forming a closed electromagnetic shielding loop.

[0071] The fanless solid-state cooling module can choose between gas self-circulation or Peltier solutions depending on the system's heat output. It achieves a high thermal conductivity path through the AlN substrate, enabling the system to operate continuously for extended periods.

[0072] In this embodiment, the method of dynamically adjusting the inverter output power using the proportional-integral algorithm is as follows: the temperature and pressure signals of the liquid source bottle wall are compared with the target set temperature and pressure values ​​to obtain the temperature deviation and pressure deviation values, and then weighted and superimposed according to the preset weight coefficients to obtain the power control comprehensive error signal, which is input to the proportional-integral controller to limit the integral term or perform anti-integral saturation processing to adjust the inverter output power.

[0073] In this embodiment, the method for generating the directional eddy current heating signal is as follows: according to the inverter output power adjustment command output by the proportional-integral controller, the amplitude of the intermediate frequency induction heating current output by the full-bridge insulated inverter topology is adjusted, and under the condition that the frequency of the intermediate frequency induction heating current is in the load resonance tracking state, the current phase and on / off timing of the induction heating coil are controlled to generate the corresponding directional eddy current heating signal.

[0074] In this embodiment, the process of transmitting the directional eddy current heating signal using the differential serial communication protocol is as follows: the directional eddy current heating signal is differentially encoded so that the same signal is transmitted in the form of a pair of electrical signals with equal amplitude and opposite phase, and the power adjustment parameters in the directional eddy current heating signal are encapsulated according to the frame structure to transmit the directional eddy current heating signal under strong electromagnetic interference environment.

[0075] In this embodiment, the fanless cooling solution includes a gas holder self-circulating gas cooling system and a Peltier solid-state active cooling heat dissipation system;

[0076] The gas holder self-circulating gas cooling system has a built-in spiral guide channel, which allows the gas inside the gas holder to generate natural convection after being heated and circulate along a preset path. It also uses the density difference formed by the temperature gradient inside the gas holder to drive the gas self-circulation flow, transferring heat from the high-temperature area to the gas holder wall or heat dissipation structure, forming a gas holder gas production-heat dissipation cavity-downstream self-circulation loop.

[0077] The Peltier solid-state active cooling and heat dissipation system applies a control current to control the thermal coupling between the cold end and the heat-generating end, actively extracts the heat generated by the heat-generating end, and thermally connects it with the heat dissipation structure, releasing the extracted heat to the external environment to complete active temperature control and heat dissipation.

[0078] In this embodiment, the method for setting the safe cooling temperature range is as follows: based on the allowable operating temperature range of the liquid source bottle, the corresponding minimum safe temperature threshold and maximum safe temperature threshold are determined, and the minimum safe temperature threshold and maximum safe temperature threshold are modified in combination with the heat dissipation capacity of the gas holder self-circulating gas cooling system and the Peltier solid-state active cooling heat dissipation system under the fanless cooling scheme, so as to set the safe cooling temperature range.

[0079] In this embodiment, the method for limiting the execution power using the built-in safety interlock logic is as follows: based on the impedance state of the intermediate frequency induction heating load and the operating state of the cooling system, it is determined whether there is over-temperature or abnormal load impedance. When any parameter is detected to exceed the corresponding safety threshold, safety interlock control is triggered, and power limitation is executed according to the level of abnormality. The safety interlock control includes: when a minor abnormality is detected, inverter output power limitation or frequency offset control is executed; when a moderate abnormality is detected, the Peltier solid-state active cooling system is triggered and the output of the directional eddy current heating signal is limited; when a severe abnormality is detected, the full-bridge insulated inverter topology is immediately shut down and the system is kept in a locked state until the abnormality is resolved or the system is reset. The interlock state is maintained until the abnormal state is resolved.

[0080] This invention also provides a dual-loop control system for semiconductor liquid source medium-frequency induction heating, specifically including:

[0081] Intermediate Frequency Resonance Control Module: Acquires the intermediate frequency induced current frequency, controls the frequency range of the output intermediate frequency AC power based on the full-bridge insulated inverter topology, and synchronously adjusts the resonant frequency through a phase-locked loop to ensure that the inverter output frequency always tracks the load resonant point, providing the basis for liquid source heating control;

[0082] Temperature and pressure dual-loop control module: Constructs a temperature-pressure dual-loop feedback curve to collect the temperature and pressure signals of the liquid source bottle wall in real time, compare them with the corresponding target set values, generate temperature deviation signals and pressure deviation signals, dynamically adjust the inverter output power through proportional-integral algorithm, control the amplitude and distribution of the medium frequency induction heating current, and generate directional eddy current heating signals.

[0083] Differential shielded transmission module: Based on the return path formed by the induced current of the directional eddy current heating signal, a closed electromagnetic shielding circuit is constructed, and the signal is transmitted to the flexible heating coil through a twisted-pair shielded wire and a differential signal interface via a differential serial communication protocol to induce the eddy current heating liquid source;

[0084] Cooling interlock limiting module: Based on the fanless cooling scheme, it controls the temperature of the induced eddy current heat source and adjusts the cooling intensity by linking the intermediate frequency induced electric frequency. When the liquid source temperature deviates from the preset safe cooling temperature range, it performs power limiting based on the built-in safety interlock logic when the load impedance is abnormal.

[0085] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A dual-loop control method for semiconductor liquid source medium-frequency induction heating, characterized in that, include: S1: Obtain the intermediate frequency induced current frequency, control the frequency range of the output intermediate frequency AC power based on the full-bridge insulated inverter topology, and synchronously adjust the resonant frequency through the phase-locked loop so that the inverter output frequency always tracks the load resonant point, providing the basis for liquid source heating control; S2: Construct a temperature-pressure dual-loop feedback curve to collect the temperature and pressure signals of the liquid source bottle wall in real time, and compare them with the corresponding target set values ​​to generate temperature deviation signals and pressure deviation signals. Dynamically adjust the inverter output power through the proportional-integral algorithm to control the amplitude and distribution of the medium-frequency induction heating current and generate directional eddy current heating signals. S3: Based on the return path formed by the induced current of the directional eddy current heating signal, a closed electromagnetic shielding circuit is constructed, and transmitted to the flexible heating coil through a twisted-pair shielded wire and a differential signal interface via a differential serial communication protocol to induce the eddy current heating liquid source. S4: Based on the fanless cooling scheme, the temperature of the induction eddy current heat source is controlled, and the cooling intensity is adjusted by linking the intermediate frequency induction frequency. When the liquid source temperature is detected to deviate from the preset safe cooling temperature range, the power limit is executed based on the built-in safety interlock logic when the load impedance is abnormal.

2. The method according to claim 1, characterized in that, The method for obtaining the intermediate frequency induced electric frequency is as follows: the equivalent impedance model of the intermediate frequency induction heating load is performed, the resonant frequency range of the load system is calculated, intermediate frequency sweep detection is performed, the inverter output voltage and current signals are collected to calculate the phase difference between the voltage and current, and the actual resonant frequency of the load is determined according to the frequency point with the smallest phase difference or the largest current amplitude. This frequency is used as the initial output frequency to obtain the intermediate frequency induced electric frequency.

3. The method according to claim 1, characterized in that, The method for controlling the frequency range of the output intermediate frequency AC power in the full-bridge insulated inverter topology is as follows: a target frequency range for the inverter output intermediate frequency AC power is preset according to the heating power requirement of the intermediate frequency induction heating load. Within the target frequency range, the drive signal of the full-bridge inverter power switch is frequency modulated to limit the operating frequency of the inverter output AC power to not exceed the upper and lower limits of the target frequency range. The target frequency range is used as the frequency constraint condition of the phase-locked loop. When the load resonant frequency changes, the output frequency of the phase-locked loop is always limited to the target frequency range, thereby controlling the frequency range of the output intermediate frequency AC power.

4. The method according to claim 1, characterized in that, The method for synchronously adjusting the resonant frequency of the phase-locked loop is as follows: calculate the phase difference between the intermediate frequency AC voltage signal and the intermediate frequency AC current signal output by the full-bridge insulated inverter topology, use the phase difference as the phase error signal of the phase-locked loop, and filter and feed back the phase error signal through the phase-locked loop to dynamically adjust the resonant frequency of the intermediate frequency AC power output by the inverter.

5. The method according to claim 2, characterized in that, The method for constructing the temperature-pressure dual-loop feedback curve is as follows: Target temperature and target pressure curves are set according to the characteristics and process requirements of the semiconductor liquid source. The temperature signal of the liquid source bottle wall and the internal pressure signal are filtered and time-aligned, and mapped to the corresponding target positions to detect control deviation values. The control deviation values ​​include temperature control deviation and pressure control deviation. A temperature-pressure dual-loop feedback curve is constructed. When both temperature control deviation and pressure control deviation exist simultaneously, the two control quantities are coordinated according to a preset priority rule to obtain feedback data of the inverter output power.

6. The method according to claim 5, characterized in that, The method of dynamically adjusting the inverter output power using the proportional-integral algorithm is as follows: the temperature and pressure signals of the liquid source bottle wall are compared with the target set temperature and pressure values ​​to obtain the temperature deviation and pressure deviation values, and then weighted and superimposed according to the preset weight coefficients to obtain the power control comprehensive error signal, which is input to the proportional-integral controller to limit the integral term or perform anti-integral saturation processing to adjust the inverter output power.

7. The method according to claim 4, characterized in that, The method for generating the directional eddy current heating signal is as follows: according to the inverter output power adjustment command output by the proportional-integral controller, the amplitude of the intermediate frequency induction heating current output by the full-bridge insulated inverter topology is adjusted, and under the condition that the frequency of the intermediate frequency induction heating current is in the load resonance tracking state, the current phase and on / off timing of the induction heating coil are controlled to generate the corresponding directional eddy current heating signal.

8. The method according to claim 2, characterized in that, The process of transmitting directional eddy current heating signals using the differential serial communication protocol is as follows: the directional eddy current heating signals are differentially encoded so that the same signal is transmitted in the form of a pair of electrical signals with equal amplitude and opposite phase, and the power adjustment parameters in the directional eddy current heating signals are encapsulated according to the frame structure to transmit directional eddy current heating signals under strong electromagnetic interference environment.

9. The method according to claim 4, characterized in that, The fanless cooling solution includes a gas holder self-circulating gas cooling system and a Peltier solid-state active cooling heat dissipation system. The gas holder self-circulating gas cooling system has a built-in spiral guide channel, which allows the gas inside the gas holder to generate natural convection after being heated and circulate along a preset path. It also uses the density difference formed by the temperature gradient inside the gas holder to drive the gas self-circulation flow, transferring heat from the high-temperature area to the gas holder wall or heat dissipation structure, forming a gas holder gas production-heat dissipation cavity-downstream self-circulation loop. The Peltier solid-state active cooling and heat dissipation system applies a control current to control the thermal coupling between the cold end and the heat-generating end, actively extracts the heat generated by the heat-generating end, and thermally connects it with the heat dissipation structure, releasing the extracted heat to the external environment to complete active temperature control and heat dissipation.

10. The method according to claim 2, characterized in that, The method for setting the safe cooling temperature range is as follows: Based on the allowable operating temperature range of the liquid source bottle, determine the corresponding minimum safe temperature threshold and maximum safe temperature threshold, and combine the heat dissipation capacity of the gas holder self-circulating gas cooling system and the Peltier solid-state active cooling heat dissipation system under the fanless cooling scheme to modify the minimum safe temperature threshold and maximum safe temperature threshold, and set the safe cooling temperature range.

11. The method according to claim 7, characterized in that, The method for limiting the execution power using the built-in safety interlock logic is as follows: Based on the impedance state of the intermediate frequency induction heating load and the operating state of the cooling system, it is determined whether there is over-temperature or abnormal load impedance. When any parameter is detected to exceed the corresponding safety threshold, the safety interlock control is triggered, and power limitation is executed according to the level of abnormality. The safety interlock control includes: when a minor abnormality is detected, the inverter output power is limited or the frequency offset is controlled; when a moderate abnormality is detected, the Peltier solid-state active cooling system is triggered and the output of the directional eddy current heating signal is limited; when a severe abnormality is detected, the full-bridge insulated inverter topology is immediately shut down and the system is kept in a locked state until the abnormality is resolved or the system is reset, and the interlock state is maintained until the abnormality is resolved.

12. A dual-loop control system for semiconductor liquid source medium-frequency induction heating, used to execute the method as described in any one of claims 1-11, characterized in that, include: Intermediate Frequency Resonance Control Module: Acquires the intermediate frequency induced current frequency, controls the frequency range of the output intermediate frequency AC power based on the full-bridge insulated inverter topology, and synchronously adjusts the resonant frequency through a phase-locked loop to ensure that the inverter output frequency always tracks the load resonant point, providing the basis for liquid source heating control; Temperature and pressure dual-loop control module: Constructs a temperature-pressure dual-loop feedback curve to collect the temperature and pressure signals of the liquid source bottle wall in real time, compare them with the corresponding target set values, generate temperature deviation signals and pressure deviation signals, dynamically adjust the inverter output power through proportional-integral algorithm, control the amplitude and distribution of the medium frequency induction heating current, and generate directional eddy current heating signals. Differential shielded transmission module: Based on the return path formed by the induced current of the directional eddy current heating signal, a closed electromagnetic shielding circuit is constructed, and the signal is transmitted to the flexible heating coil through a twisted-pair shielded wire and a differential signal interface via a differential serial communication protocol to induce the eddy current heating liquid source; Cooling interlock limiting module: Based on the fanless cooling scheme, it controls the temperature of the induced eddy current heat source and adjusts the cooling intensity by linking the intermediate frequency induced electric frequency. When the liquid source temperature deviates from the preset safe cooling temperature range, it performs power limiting based on the built-in safety interlock logic when the load impedance is abnormal.

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