A temperature control device and control method for semiconductor

Abstract

This application relates to a semiconductor-specific temperature control device and control method. The semiconductor-specific temperature control device includes: two cascade refrigeration systems and a circulation system; each cascade refrigeration system includes a high-temperature stage subsystem and a low-temperature stage subsystem, and each includes a first evaporator and a second evaporator located at the heat exchange end of the low-temperature stage subsystem; the first evaporator and the second evaporator are connected in series in the circulation pipeline of the circulation system, and the circulating fluid to be cooled flows through the first evaporator and the second evaporator in sequence for heat exchange; the circulation system includes a heater located upstream of the circulation outlet; and a control system capable of controlling the cooling output of the two cascade refrigeration systems and the heating output of the heater according to the set first outlet target pressure of the first cascade refrigeration system, the second outlet target pressure of the second cascade refrigeration system, and the outlet target temperature of the circulating fluid.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing technology, and more specifically, to a semiconductor-specific temperature control device and control method. Background Technology

[0002] Temperature is one of the key parameters for physical and chemical reactions in the etching process of integrated circuit manufacturing. Semiconductor-specific temperature control equipment provides a constant temperature and flow rate of circulating fluid for use in integrated circuit manufacturing processes, removing heat generated during the process and meeting the temperature control requirements of the main semiconductor process equipment.

[0003] With the development of advanced process technology, the more advanced the process, the greater the etching aspect ratio is required. High aspect ratio etching requires the introduction of low temperature etching technology to meet process requirements. Semiconductor-specific temperature control equipment used in advanced processes should be able to provide a sufficiently low temperature range.

[0004] As the temperature requirements for temperature control equipment change from -20℃ and -40℃ to -60℃ and -80℃, the system principle of the temperature control equipment also changes from a single-stage system to a cascade system. Due to the need for improved etching precision, a low-temperature environment can suppress the lateral diffusion of the etching reaction, enhance anisotropy, and thus improve the accuracy of pattern transfer. At the same time, low temperature helps maintain the high density and uniformity of plasma, avoiding uneven electron energy distribution caused by high temperature, thereby improving etching rate and uniformity. During the etching process, plasma action releases a large amount of heat, so cascade systems need strong cooling capabilities while meeting the low temperature requirements.

[0005] Common existing technologies include direct liquid nitrogen cooling systems, Stirling refrigerators, and GM refrigerators. However, Stirling and GM refrigerators have a cooling capacity of only 1-2 kW at -80°C, which is lower than that of vapor compression refrigeration systems and does not meet the requirements. Direct liquid nitrogen cooling systems face challenges in temperature control over a wide temperature range and also consume liquid nitrogen, resulting in high operating costs.

[0006] Other existing refrigeration systems are limited by the specifications of existing components such as compressor power, and the maximum cooling capacity that can be achieved at -80℃ is about 5-6kW, which cannot meet the process requirements of the main process equipment during the etching process. Summary of the Invention

[0007] The purpose of this application is to provide a semiconductor-specific temperature control device and control method, which can realize the automatic control of the temperature of a high-low temperature cascade system, and enable the temperature control device to achieve a maximum cooling capacity of more than 10kW at -80℃.

[0008] To achieve the above objectives, in a first aspect, the present invention provides a semiconductor-specific temperature control device, comprising: a first cascade cooling system, a second cascade cooling system, and a circulation system for load-side circulating fluid; Each cascade refrigeration system includes a high-temperature stage subsystem and a low-temperature stage subsystem, and each includes a first evaporator and a second evaporator located at the heat exchange end of the low-temperature stage subsystem. The first evaporator and the second evaporator are connected in series in the circulation pipeline of the circulation system. The circulating fluid to be cooled flows through the first evaporator and the second evaporator in sequence for heat exchange. The circulation system includes a heater located upstream of the circulation outlet. The control system is capable of controlling the cooling output of the two cascade refrigeration systems and the heating output of the heater based on the set first outlet target pressure of the first cascade refrigeration system, the second outlet target pressure of the second cascade refrigeration system, and the outlet target temperature of the circulating fluid.

[0009] In an optional embodiment, the circulation pipeline is sequentially provided with a circulation water tank, a circulation water pump, a first evaporator, a second evaporator, and a heater; The control system integrates a PID controller, and the frequency converter of the circulating water pump and the heater are electrically connected to the PID controller.

[0010] In an optional embodiment, the circulation pipeline is sequentially equipped with a return temperature sensor, a first evaporator outlet temperature sensor, a second evaporator outlet temperature sensor, and an outlet temperature sensor along the direction of circulation fluid flow. An intermediate evaporator-condenser is provided between the high-temperature stage subsystem and the low-temperature stage subsystem. The return outlet temperature sensor is located upstream of the circulating water tank and is used to detect the actual return outlet temperature. The first evaporator outlet temperature sensor is located downstream of the first evaporator and is used to detect the actual outlet temperature of the first evaporator. The second evaporator outlet temperature sensor is located downstream of the second evaporator and is used to detect the actual outlet temperature of the second evaporator. The outlet temperature sensor is located downstream of the heater and is used to detect the actual outlet temperature. A first pressure sensor is installed on the main circulation path downstream of the intermediate evaporator and condenser of the first cascade refrigeration system to detect the actual pressure at the first outlet. A second pressure sensor is installed on the main circulation path downstream of the intermediate evaporator and condenser in the second cascade refrigeration system to detect the actual pressure at the second outlet. Different temperature sensors and different pressure sensors are electrically connected to the PID controller.

[0011] In an optional embodiment, the high-temperature stage subsystem and the low-temperature stage subsystem respectively include a compressor, a main circulation circuit, a main expansion valve, and a hot gas bypass pipeline, wherein a hot gas bypass expansion valve is provided on the hot gas bypass pipeline. The compressor's frequency converter, the main expansion valve, and the hot gas bypass expansion valve are all electrically connected to the PID controller.

[0012] In an optional implementation, the control system controls the PID controller to output a control signal based on the deviation between the actual value and the target value collected by the temperature sensor and the pressure sensor, and transmits the control signal to the frequency converter of the compressor, the main expansion valve, the hot gas bypass expansion valve and the heater; By implementing closed-loop control between the control signal and the actuator, the temperature of the circulating fluid during the heat exchange process through the two-stage series evaporator is controlled to ensure that the actual value matches the target value.

[0013] Secondly, the present invention provides a control method for a semiconductor-specific temperature control device, used to control the semiconductor-specific temperature control device as described in any of the foregoing embodiments, comprising the following steps: Set the target outlet temperature, the first target outlet pressure, and the second target outlet pressure; The control system automatically calculates the first target temperature at the outlet of the first evaporator and the second target temperature at the outlet of the second evaporator based on the outlet target temperature, wherein: The second target temperature is set to be lower than the first preset difference from the outlet target temperature; The first target temperature is set to be lower than the second preset difference from the outlet target temperature; The value of the second preset difference is such that, under the maximum load condition, the cooling capacity temperature difference of the first cascade refrigeration system is equal to the cooling capacity temperature difference of the second cascade refrigeration system. The control system controls the low-temperature stage subsystems of the two cascade refrigeration systems to operate according to their respective target evaporation temperatures, so that the circulating fluid reaches the required outlet temperature after passing through the two stages of evaporation in sequence. Meanwhile, the control system controls the high-temperature stage subsystems of the two cascade refrigeration systems to operate according to their respective outlet target pressures based on the deviations between the first outlet target pressure and the second outlet target pressure and the first outlet actual pressure and the second outlet actual pressure.

[0014] In an optional implementation, the first preset difference and the second preset difference are preset according to the temperature range of the outlet target temperature. Different temperature ranges correspond to different first preset difference and second preset difference, so as to achieve automatic balanced distribution of the two-stage cooling capacity across the entire temperature range.

[0015] In an optional implementation, the PID controller controls the output ratio of the heater based on the deviation between the target outlet temperature and the actual outlet temperature, thereby adjusting the temperature of the circulating fluid after two stages of evaporation and heat exchange to stabilize the outlet temperature at the target outlet temperature.

[0016] In an optional implementation, the high-temperature stage subsystems of the first cascade refrigeration system and the second cascade refrigeration system respectively use the outlet pressure of the intermediate evaporator condenser as the control target. The PID controller calculates the cooling capacity of the high-temperature stage subsystem by the deviation between the first outlet target pressure and the second outlet target pressure and the actual first outlet pressure and the actual second outlet pressure.

[0017] In an optional implementation, under no-load, constant load, variable load, or temperature rise / fall conditions, the control system dynamically adjusts the cooling capacity output of the two cascade refrigeration systems based on the deviation between the target outlet temperature and the actual temperature and its rate of change, so that the cooling capacity of the two cascade refrigeration systems can automatically match the load.

[0018] The semiconductor-specific temperature control device and control method in this application can form a two-stage cascade system by cooperating a high-temperature stage subsystem and a low-temperature stage subsystem. By controlling the two cascade systems in series, the cooling capacity at low temperatures can be greatly improved.

[0019] At the same time, by controlling the target temperature of the two cascade systems separately, the system can achieve the maximum cooling capacity output of the system at single point temperature and during temperature rise and fall within the entire temperature range under different operating conditions.

[0020] The circulating fluid exchanges heat through two evaporators, which improves the temperature accuracy under no-load and constant load conditions. In addition, under variable load conditions, the cooling and heat exchange through two sets of series systems also improves the temperature control accuracy and temperature response under variable load conditions.

[0021] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the system principle of the semiconductor-specific temperature control device of this application; Figure 2This is a schematic diagram illustrating the control principle of the semiconductor-specific temperature control device of this application; Figure 3 This is a schematic diagram of the control process of the semiconductor-specific temperature control device of this application.

[0024] Figure label: 1-First cascade refrigeration system; 11-First high-temperature stage subsystem; 111-First high-temperature compressor; 112-First high-temperature frequency converter; 113-First high-temperature condenser; 114-First high-temperature main electronic expansion valve; 115-First high-temperature hot gas bypass electronic expansion valve; 116-First high-temperature intermediate evaporator condenser; 117-First high-temperature suction pressure sensor; 12-First cryogenic stage subsystem; 121-First cryogenic compressor; 122-First cryogenic frequency converter; 123-First cryogenic main electronic expansion valve; 124-First cryogenic hot gas bypass electronic expansion valve; 10-First evaporator; 125-First cryogenic suction pressure sensor; 2-Second cascade refrigeration system; 21-Second high-temperature stage subsystem; 211-Second high-temperature compressor; 212-Second high-temperature frequency converter; 213-Second high-temperature condenser; 214-Second high-temperature main electronic expansion valve; 215-Second high-temperature hot gas bypass electronic expansion valve; 216-Second high-temperature intermediate evaporator condenser; 217-Second high-temperature suction pressure sensor; 22-Second cryogenic stage subsystem; 221-Second cryogenic compressor; 222-Second cryogenic frequency converter; 223-Second cryogenic main electronic expansion valve; 224-Second cryogenic hot gas bypass electronic expansion valve; 20-Second evaporator; 225-Second cryogenic suction pressure sensor; 3-Circulation system; 31-Circulating water tank; 32-Circulating water pump; 33-Heater; 41 - Return temperature sensor; 42 - First evaporator outlet temperature sensor; 43 - Second evaporator outlet temperature sensor; 44 - Outlet temperature sensor. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0026] In the description of this application, it should be noted that the terms "inner" and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0027] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "setup" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0028] See Figure 1 and combined Figures 2-3 The semiconductor-specific temperature control device in this application mainly achieves greater cooling capacity under low-temperature conditions by connecting two sets of cascade refrigeration systems in series and exchanging heat with the circulating medium.

[0029] The two cascade refrigeration systems are controlled by the target refrigeration temperature, which is linked to the outlet target temperature, to achieve automatic control over the entire temperature range.

[0030] The pre-stage and post-stage cascade refrigeration systems obtain the corresponding output cooling capacity through PID control based on their respective target temperatures and corresponding actual temperature deviations. The cooling capacity is then used to control the automatic operation of their respective low-temperature stage valves.

[0031] The semiconductor-specific temperature control device in this application includes: a first cascade cooling system 1, a second cascade cooling system 2, a circulation system 3 for the load-side circulating fluid, a sensor for detecting parameters such as temperature and pressure, and a control system.

[0032] Each cascade refrigeration system includes a high-temperature stage subsystem and a low-temperature stage subsystem, and includes a first evaporator 10 and a second evaporator 20 located at the heat exchange end of the low-temperature stage subsystem. An intermediate evaporator-condenser is provided between the high-temperature stage subsystem and the low-temperature stage subsystem.

[0033] The first evaporator 10 and the second evaporator 20 are connected in series in the circulation system, and the circulating fluid to be cooled flows through the first evaporator and the second evaporator in sequence for heat exchange.

[0034] The circulation system 3 includes a circulating water tank 31, a circulating water pump 32, and a heater 33 arranged sequentially along the direction of circulating fluid flow.

[0035] In its specific structure, the circulation pipeline is sequentially equipped with a circulating water tank, a circulating water pump, a first evaporator, a second evaporator, and a heater. The heater 33 is located upstream of the circulation outlet of the overall circulation system. The control system integrates a PID controller, and the frequency converter of the circulating water pump and the heater are electrically connected to the PID controller.

[0036] The control system can control the cooling output of the two cascade refrigeration systems and the heating output of the heater 33 respectively, based on the set first outlet target pressure of the first cascade refrigeration system 1, the second outlet target pressure of the second cascade refrigeration system 2, and the outlet target temperature of the circulating fluid.

[0037] Specifically, the first cascade refrigeration system 1 includes a first high-temperature stage subsystem 11 and a first low-temperature stage subsystem 12.

[0038] The first high-temperature stage subsystem 11 includes a first high-temperature compressor 111, a first high-temperature frequency converter 112, a first high-temperature condenser 113, a first high-temperature main electronic expansion valve 114, a first high-temperature hot gas bypass electronic expansion valve 115, a first high-temperature intermediate evaporator condenser 116, and a first high-temperature suction pressure sensor 117.

[0039] The first cryogenic stage subsystem 12 includes a first cryogenic compressor 121, a first cryogenic frequency converter 122, a first cryogenic main electronic expansion valve 123, a first cryogenic hot gas bypass electronic expansion valve 124, a first evaporator 10, and a first cryogenic suction pressure sensor 125.

[0040] The condensate is condensed by the first high-temperature condenser 113 for the first high-temperature stage subsystem 11, and the first evaporator 10 exchanges heat between the circulating fluid and the refrigeration system to change the temperature of the circulating liquid.

[0041] The second cascade refrigeration system 2 includes a second high-temperature stage subsystem 21 and a second low-temperature stage subsystem 22.

[0042] The second high-temperature stage subsystem 21 includes a second high-temperature compressor 211, a second high-temperature frequency converter 212, a second high-temperature condenser 213, a second high-temperature main electronic expansion valve 214, a second high-temperature hot gas bypass electronic expansion valve 215, a second high-temperature intermediate evaporator condenser 216, and a second high-temperature suction pressure sensor 217.

[0043] The second cryogenic stage subsystem 22 includes a second cryogenic compressor 221, a second cryogenic frequency converter 222, a second cryogenic main electronic expansion valve 223, a second cryogenic hot gas bypass electronic expansion valve 224, a second evaporator 20, and a second cryogenic suction pressure sensor 225.

[0044] The condensate is condensed by the second high-temperature condenser 213 for the second high-temperature stage subsystem 21, and the second evaporator 20 exchanges heat between the circulating fluid and the refrigeration system to change the temperature of the circulating liquid.

[0045] The inverter, main expansion valve, and hot gas bypass expansion valve of the compressor are electrically connected to the PID controller.

[0046] From the perspective of circulating fluid flowing in series through two cascade refrigeration systems, the circulating fluid is pumped into the inlet of the first evaporator 10 after passing through the circulating water pump. After the first-stage heat exchange, the circulating fluid enters the second evaporator 20. After the second-stage heat exchange, it is connected to the inlet of the heater 33 and enters the heater for heat regulation.

[0047] The control system integrates a PID controller, and the frequency converter of the circulating water pump 32 and the heater 33 are electrically connected to the PID controller.

[0048] In the attached diagram, IN represents the return port of the circulating fluid, and OUT represents the outlet port of the circulating fluid. The outlet port and the return port are connected to the main process equipment. A return port temperature sensor 41, a first evaporator outlet temperature sensor 42, a second evaporator outlet temperature sensor 43, and an outlet temperature sensor 44 are also installed on the circulation pipeline of circulation system 3. The system principle of the entire equipment is as follows: Figure 1 As shown.

[0049] The semiconductor-specific temperature control equipment control system acquires the actual values ​​from temperature and pressure sensors through a data acquisition module. Based on the actual values ​​and the given target values, the system inputs them into a PID controller to obtain the output value. The output value controls the high-temperature and low-temperature subsystems, ultimately ensuring that the actual values ​​and the given target values ​​are consistent.

[0050] The circulation pipeline is equipped with a return temperature sensor, a first evaporator outlet temperature sensor, a second evaporator outlet temperature sensor, and an outlet temperature sensor in sequence along the direction of the circulating fluid flow.

[0051] Specifically, the return temperature sensor 41 is located upstream of the circulating water tank 31 and is used to detect the actual return temperature TS2. The first evaporator outlet temperature sensor 42 is located downstream of the first evaporator 10 and is used to detect the actual outlet temperature TS3 of the first evaporator 10. The second evaporator outlet temperature sensor 43 is located downstream of the second evaporator 20 and is used to detect the actual outlet temperature TS4 of the second evaporator 20. The outlet temperature sensor 44 is located downstream of the heater 33 and is used to detect the actual outlet temperature TS1. A first pressure sensor is installed on the main circulation line downstream of the first high-temperature intermediate evaporator 116 to detect the actual pressure PS112 at the first outlet. A second pressure sensor is installed on the main circulation path downstream of the second high-temperature intermediate evaporator 216 to detect the actual pressure PS212 at the second outlet. Different temperature sensors and different pressure sensors are electrically connected to the PID controller.

[0052] The control system controls the PID controller to output control signals based on the deviation between the actual values ​​collected by the temperature sensor and the pressure sensor and the target values, and transmits the control signals to the compressor's frequency converter, main expansion valve, hot gas bypass expansion valve, heater 33 and circulating water pump 32. By implementing closed-loop control between control signals and actuators, the temperature of the circulating fluid during the heat exchange process through the series evaporators is controlled to ensure that the actual value matches the target value.

[0053] Combination Figure 3 This application also provides a control method for a semiconductor-specific temperature control device, used to control the aforementioned semiconductor-specific temperature control device, comprising the following steps: Set the overall target outlet temperature Ta, the first target outlet pressure Pa1, and the second target outlet pressure Pa2 for the semiconductor-specific temperature control equipment; The control system automatically calculates the first outlet temperature Ta1 of the first evaporator 10 and the second outlet target temperature Ta2 of the second evaporator 20 based on the outlet target temperature.

[0054] The second outlet temperature Ta2 is set to be lower than the second preset difference x of the outlet target temperature, and the first outlet temperature Ta1 is set to be lower than the first preset difference y of the outlet target temperature.

[0055] Furthermore, the value of the second preset difference y is such that, under the maximum load condition, the cooling capacity temperature difference of the first cascade refrigeration system is equal to the cooling capacity temperature difference of the second cascade refrigeration system. The control system controls the low-temperature stage subsystems of the two cascade refrigeration systems to operate according to their respective cross-flow outlet target temperatures Ta1 and Ta2, so that the circulating fluid after cross-flow flows through the first evaporator 10 and the second evaporator 20 in sequence to reach the required outlet temperature.

[0056] The control system controls the high-temperature stage subsystems of the two cascade refrigeration systems to operate according to their respective outlet target pressures based on the deviations between the first outlet target pressure Pa1 and the second outlet target pressure Pa2 and the first outlet actual pressure PS112 and the second outlet actual pressure PS212.

[0057] Specifically, the first cryogenic stage subsystem 12 controls the stability of the outlet temperature of the first evaporator 10. The cooling capacity C1L is obtained by calculating the deviation between the first outlet target temperature Ta1 and the actual outlet temperature TS3 through a PID controller. The cooling capacity C1L controls the frequency of the first cryogenic compressor 121 and the opening value of the electronic expansion valve in the first cryogenic stage subsystem 12, thereby ensuring that the actual outlet temperature TS3 is controlled at the first target temperature Ta1.

[0058] The first high-temperature stage subsystem 11 controls the stability of the outlet pressure of the first high-temperature intermediate evaporator condenser 116. The refrigeration capacity C1H is obtained by calculating the deviation between the target pressure Pa1 and the actual pressure P112 through a PID controller. The refrigeration capacity C1H controls the frequency of the first high-temperature compressor 111 and the opening value of the electronic expansion valve in the first high-temperature stage subsystem 11, thereby ensuring that the outlet pressure P112 is controlled at the target pressure Pa1.

[0059] The second cryogenic stage subsystem 22 controls the stability of the outlet temperature of the second evaporator 20. The refrigeration capacity C2L is obtained by calculating the deviation between the target outlet temperature Ta2 and the actual outlet temperature TS4 through a PID controller. The refrigeration capacity C2L controls the frequency of the second cryogenic compressor 221 and the opening value of the electronic expansion valve in the second cryogenic stage subsystem 22, thereby ensuring that the actual outlet temperature TS4 is controlled at the target temperature Ta2.

[0060] The second high-temperature stage subsystem 21 controls the stability of the outlet pressure of the second high-temperature intermediate evaporator condenser 216. The refrigeration capacity C2H is obtained by calculating the deviation between the target pressure Pa2 and the actual pressure PS212 through a PID controller. The refrigeration capacity C2H controls the frequency of the second high-temperature compressor 211 and the opening value of the electronic expansion valve in the second high-temperature stage subsystem 21, thereby ensuring that the outlet pressure P212 is controlled at the target pressure Pa2.

[0061] In the specific control process, the heater 33 controller controls the stability of the outlet temperature. The heating amount Hout is obtained by the PID controller after the deviation between the target outlet temperature Ta and the actual outlet temperature TS1. The heating amount is converted into the duty cycle to control the output ratio of the heater 33, and the temperature of the circulating fluid is adjusted to ensure that the outlet temperature is controlled at the target outlet temperature Ta.

[0062] The first preset difference x and the second preset difference y in this application are preset according to the temperature range of the outlet target temperature Ta. Different temperature ranges correspond to different first preset difference x and second preset difference y, so as to realize the automatic balanced distribution of the cooling capacity of the two cascade refrigeration systems across the entire temperature range.

[0063] Furthermore, the first outlet target temperature Ta1 of the first cryogenic stage subsystem 12 and the second outlet target temperature Ta2 and outlet target temperature Ta of the second cryogenic stage subsystem 22 are correlated.

[0064] After Ta2 is heated by the heater, its temperature reaches Ta, and Ta2 = Ta - x.

[0065] For the target temperature Ta1, TS2-Ta1 is the temperature difference of the cooling output corresponding to the first low-temperature stage subsystem 12; Ta1-Ta2 is the temperature difference of the cooling output corresponding to the second low-temperature stage subsystem 22.

[0066] The actual temperature of the TS2 return port will be higher than Ta1 under no-load conditions, and will increase with the load size under load conditions. This application defines Ta1 = Ta - y. The setting of y needs to take into account the cooling capacity output of the first cryogenic stage subsystem 12 and the second cryogenic stage subsystem 22 (to meet the overall output requirements), and to meet the balance of the output of the two systems under maximum load, that is, TS2 - Ta1 = Ta1 - Ta2. Based on the above formula, this application can derive y = Ta - (TS2 + Ta2) / 2.

[0067] Taking the outlet temperature as an example, assuming the temperature range is from -80℃ to 30℃, and using 10℃ intervals, the full-range temperature can be divided into 10 temperature intervals. The details of each temperature interval are omitted. For each temperature interval, a first preset difference y corresponding to the first outlet target temperature Ta1 of the first cryogenic stage subsystem 12 can be set separately, and a second preset difference x corresponding to the second outlet target temperature Ta2 of the second cryogenic stage subsystem 22 can be set separately. For example, at -80℃, Ta = -80℃, Ta1 = -77℃, and Ta2 = -83℃.

[0068] The temperature range is between -80℃ and -70℃, x takes a value of 3℃, and y takes a value of -3℃; The temperature range is between -70℃ and -60℃, with x taking the value of 3℃ and y taking the value of -4℃; The temperature range is between -60℃ and -50℃, x takes a value of 4℃, and y takes a value of -4℃; The temperature range is between -50℃ and -40℃, with x taking the value of 4℃ and y taking the value of -4℃.

[0069] By setting different preset differences within different temperature ranges, precise temperature control in different zones and grades can be achieved. This effectively compensates for the heat exchange attenuation caused by the decrease in refrigerant mass flow rate and evaporation pressure at low temperatures, making the actual outlet temperature Ta closer to the theoretical target value, and compressing the absolute deviation across the entire range to an acceptable range.

[0070] At the same time, it can effectively increase the system's regulation inertia range, avoid frequent valve operation due to oversensitivity, and extend equipment life.

[0071] By using the above control method, combined with setting the overall outlet target temperature Ta, first outlet target pressure Pa1 and second outlet target pressure Pa2 of the semiconductor-specific temperature control equipment in this application, the first outlet target temperature Ta1 of the first low temperature stage subsystem 12 and the second outlet target temperature Ta2 of the second low temperature stage subsystem 22 can be automatically calculated based on the outlet target temperature Ta, thus forming an automatic control form.

[0072] Based on this, since semiconductor-specific temperature control equipment operates in different states—no load, constant load, variable load, or temperature rise / fall conditions—the PID controller can dynamically adjust based on the deviation and changes between the target and actual values, outputting C1L, C1H, C2L, and C2H. Furthermore, by corresponding the output magnitude to the compressor frequency and the opening degree of the electronic expansion valve in the control system, the temperature control accuracy and temperature response under variable load conditions are improved.

[0073] For the entire equipment control process, please refer to Figure 3 As shown.

[0074] The semiconductor-specific temperature control device and control method in this application control the outlet temperature according to the target temperature. The two sets of cascade refrigeration systems are controlled by the refrigeration target temperature. The two refrigeration target temperatures are automatically associated with the outlet target temperature, so as to realize the automatic control of the refrigeration capacity of the two sets of cascade refrigeration systems in the entire temperature range.

[0075] The two cascade refrigeration systems use PID control to determine the corresponding output cooling capacity based on their respective target temperatures and the corresponding actual temperature deviations. This cooling capacity then controls the automatic operation of the corresponding low-temperature stage valves. Simultaneously, the pressure downstream of the intermediate evaporator-condenser is used as a reference for the automatic operation of the high-temperature stage valves, ensuring system stability and reliability.

[0076] The two cascade refrigeration systems can greatly improve the cooling capacity compared to a single system. At the same time, through the automatic correlation of the target temperature, the cooling capacity of the two systems can be automatically output, achieving automatic operation under no-load and load conditions.

[0077] It should be noted that for the control of different operating mechanisms based on the cooling capacity, please refer to the applicant's prior published documents as technical support for the technical solution in this application, and will not be repeated here.

[0078] It should be noted that, where there is no conflict, the features in the embodiments of this application can be combined with each other.

[0079] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A semiconductor-specific temperature control device, characterized in that, include: The first cascade refrigeration system, the second cascade refrigeration system, and the circulation system of the load-side circulating fluid; Each cascade refrigeration system includes a high-temperature stage subsystem and a low-temperature stage subsystem, and each includes a first evaporator and a second evaporator located at the heat exchange end of the low-temperature stage subsystem. The first evaporator and the second evaporator are connected in series in the circulation pipeline of the circulation system. The circulating fluid to be cooled flows through the first evaporator and the second evaporator in sequence for heat exchange. The circulation system includes a heater located upstream of the circulation outlet. The control system is capable of controlling the cooling output of the two cascade refrigeration systems and the heating output of the heater based on the set first outlet target pressure of the first cascade refrigeration system, the second outlet target pressure of the second cascade refrigeration system, and the outlet target temperature of the circulating fluid.

2. The semiconductor-specific temperature control device according to claim 1, characterized in that, The circulation pipeline is sequentially equipped with a circulating water tank, a circulating water pump, a first evaporator, a second evaporator, and a heater; The control system integrates a PID controller, and the frequency converter of the circulating water pump and the heater are electrically connected to the PID controller.

3. The semiconductor-specific temperature control device according to claim 2, characterized in that, The circulation pipeline is sequentially equipped with a return temperature sensor, a first evaporator outlet temperature sensor, a second evaporator outlet temperature sensor, and an outlet temperature sensor along the direction of circulation fluid flow. An intermediate evaporator-condenser is provided between the high-temperature stage subsystem and the low-temperature stage subsystem. The return outlet temperature sensor is located upstream of the circulating water tank and is used to detect the actual return outlet temperature. The first evaporator outlet temperature sensor is located downstream of the first evaporator and is used to detect the actual outlet temperature of the first evaporator. The second evaporator outlet temperature sensor is located downstream of the second evaporator and is used to detect the actual outlet temperature of the second evaporator. The outlet temperature sensor is located downstream of the heater and is used to detect the actual outlet temperature. A first pressure sensor is installed on the main circulation path downstream of the intermediate evaporator and condenser of the first cascade refrigeration system to detect the actual pressure at the first outlet. A second pressure sensor is installed on the main circulation path downstream of the intermediate evaporator and condenser in the second cascade refrigeration system to detect the actual pressure at the second outlet. Different temperature sensors and different pressure sensors are electrically connected to the PID controller.

4. The semiconductor-specific temperature control device according to claim 2, characterized in that, The high-temperature stage subsystem and the low-temperature stage subsystem respectively include a compressor, a main circulation circuit, a main expansion valve, and a hot gas bypass pipeline, wherein a hot gas bypass expansion valve is provided on the hot gas bypass pipeline. The compressor's frequency converter, the main expansion valve, and the hot gas bypass expansion valve are all electrically connected to the PID controller.

5. The semiconductor-specific temperature control device according to claim 4, characterized in that, The control system controls the PID controller to output a control signal based on the deviation between the actual value and the target value collected by the temperature sensor and the pressure sensor, and transmits the control signal to the frequency converter of the compressor, the main expansion valve, the hot gas bypass expansion valve and the heater; By implementing closed-loop control between the control signal and the actuator, the temperature of the circulating fluid during the heat exchange process through the two-stage series evaporator is controlled to ensure that the actual value matches the target value.

6. A control method for a semiconductor-specific temperature control device, used to control the semiconductor-specific temperature control device according to any one of claims 1-5, characterized in that, Includes the following steps: Set the target outlet temperature, the first target outlet pressure, and the second target outlet pressure; The control system automatically calculates the first target temperature at the outlet of the first evaporator and the second target temperature at the outlet of the second evaporator based on the outlet target temperature, wherein: The second target temperature is set to be lower than the first preset difference from the outlet target temperature; The first target temperature is set to be lower than the second preset difference from the outlet target temperature; The value of the second preset difference is such that, under the maximum load condition, the cooling capacity temperature difference of the first cascade refrigeration system is equal to the cooling capacity temperature difference of the second cascade refrigeration system. The control system controls the low-temperature stage subsystems of the two cascade refrigeration systems to operate according to their respective target evaporation temperatures, so that the circulating fluid reaches the required outlet temperature after passing through the two stages of evaporation in sequence. Meanwhile, the control system controls the high-temperature stage subsystems of the two cascade refrigeration systems to operate according to their respective outlet target pressures based on the deviations between the first outlet target pressure and the second outlet target pressure and the first outlet actual pressure and the second outlet actual pressure.

7. The control method for the semiconductor-specific temperature control device according to claim 6, characterized in that, The first preset difference and the second preset difference are preset according to the temperature range of the outlet target temperature. Different temperature ranges correspond to different first preset difference and second preset difference, so as to realize the automatic balanced distribution of the two-stage cooling capacity across the entire temperature range.

8. The control method for the semiconductor-specific temperature control device according to claim 6, characterized in that, The PID controller controls the output ratio of the heater based on the deviation between the target outlet temperature and the actual outlet temperature, thereby adjusting the temperature of the circulating fluid after two stages of evaporation and heat exchange to stabilize the outlet temperature at the target outlet temperature.

9. The control method for the semiconductor-specific temperature control device according to claim 6, characterized in that, The high-temperature stage subsystems of the first cascade refrigeration system and the second cascade refrigeration system each use the outlet pressure of the intermediate evaporator condenser as the control target. The PID controller calculates the cooling capacity of the high-temperature stage subsystem by the deviation between the first outlet target pressure and the second outlet target pressure and the actual first outlet pressure and the actual second outlet pressure.

10. The control method for the semiconductor-specific temperature control device according to claim 6, characterized in that, Under no-load, constant load, variable load, or temperature rise / fall conditions, the control system dynamically adjusts the cooling capacity output of the two cascade refrigeration systems based on the deviation between the target outlet temperature and the actual temperature and its rate of change, so that the cooling capacity of the two cascade refrigeration systems can automatically match the load.

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