Super-static temperature control liquid cooling source system

Abstract

The utility model discloses a super-static temperature control liquid cooling source system. The system comprises a vapor compression type refrigeration cycle unit and a circulating liquid constant-temperature processing loop, according to the vapor compression type refrigeration cycle unit, a compressor, a condenser, an electronic expansion valve and an evaporator form a closed refrigerant circulation loop; an evaporation channel in the evaporator is arranged in the refrigerant circulation loop, and a cooling channel in the evaporator is arranged in the circulation liquid constant-temperature treatment loop; the circulating liquid constant-temperature treatment loop adopts constant-flow liquid supply, the circulating liquid returned by the user side is subjected to primary temperature regulation through an evaporator cooling channel, is subjected to secondary precise temperature regulation through a constant-temperature regulator, is subjected to rectification and temperature equalization through a baffle plate, and is conveyed to the user side; circulating liquid temperature control is achieved through refrigeration compressor energy control, refrigerant condensation pressure control, refrigerant evaporation temperature control and circulating liquid ultra-static constant temperature control. According to the utility model, the purpose of 10mK-level circulating liquid supply temperature precision is achieved, and the requirements of precise temperature control liquid cooling source equipment are met.

Description

Technical Field

[0001] The utility model belongs to the technical field of refrigeration and precise thermal control, and in particular relates to a liquid cooling source system with a ±10mK temperature control accuracy for precise thermal control of a nm-level lithography machine. Background Art

[0002] High-precision and high-stability temperature control is an important task in the research and development of high-end chip manufacturing equipment. Taking the control of lithography processing quality and yield as an example, the processing quality of nano-level lithography equipment is affected by factors such as temperature, pressure, and laser wavelength, respectively: temperature 4770nm / ℃, pressure 22.8nm / Mpa, wavelength 470nm / pm, so the temperature accuracy and stability requirements are extremely high. As the most temperature-sensitive components, projection lenses and laser interferometers not only have high requirements for internal single-point temperature accuracy, but also have extremely high requirements for the uniformity of their spatial temperature field. Temperature accuracy, spatial uniformity and its drift over time will seriously affect the positioning accuracy and overlay accuracy of the lithography machine. So far, there has been no public report on the relevant technology of the ±10mK temperature control accuracy liquid cooling source system for precise thermal control of nm-level lithography machines. Utility Model Content

[0003] The utility model is to avoid the deficiencies of the above-mentioned prior art and provide a super-static temperature-controlled liquid cooling source system to achieve the goal of 10mK level circulating liquid supply temperature accuracy to meet the needs of related high-end precision temperature-controlled liquid cooling source equipment.

[0004] The utility model adopts the following technical solutions to solve the technical problems:

[0005] The characteristics of the utility model super-static temperature-controlled liquid cooling source system are as follows: the system structure includes a vapor compression refrigeration cycle unit and a circulating liquid constant temperature processing circuit; the vapor compression refrigeration cycle unit is a closed refrigerant circulation circuit composed of a refrigeration compressor, a condenser, an electronic expansion valve and an evaporator connected in sequence; the condenser is an air-cooled condenser or a water-cooled condenser, the cooling medium flow of the condenser is adjustable, the condensing fan of the air-cooled condenser is equipped with a variable frequency motor, and the condensing water pump of the water-cooled condenser is equipped with a variable frequency motor; the evaporator is a double-layer evaporation channel and a cooling channel. A channel evaporator, wherein the evaporation channel is arranged in a refrigerant circulation loop, and the refrigerant passing through the evaporation channel evaporates and absorbs heat, and the cooling channel is arranged in a circulating liquid constant temperature treatment loop, and the circulating liquid passing through the cooling channel releases heat and cools down; the circulating liquid constant temperature treatment loop is an open passage for constant flow liquid supply, and the circulating liquid returned from the user end releases heat and cools down through the cooling channel of the evaporator before entering a circulating liquid tank, a baffle and a thermostat are arranged in the circulating liquid tank, the circulating liquid passing through the circulating liquid tank is temperature-controlled by the thermostat, and after being rectified and evenly heated by the baffle, it is transported to the user end by a circulating liquid pump.

[0006] The ultra-static temperature-controlled liquid cooling source system of the utility model is also characterized in that: there are N baffles arranged in the circulating liquid tank, N is not less than 3, and the inner cavity of the circulating liquid tank is divided into N+1 processes by the N baffles. The processes from the inlet end of the circulating liquid tank toward the outlet end of the circulating liquid tank are the first process, the second process and the subsequent processes in sequence. The constant temperature regulator is located in the flow channel of the first process or the second process, so that the circulating liquid is temperature-controlled when passing through the constant temperature regulator, and obtains a rectified uniform temperature when passing through each subsequent process, thereby eliminating the detection error caused by the radial temperature gradient.

[0007] The utility model super-static temperature-controlled liquid cooling source system is also characterized in that the actuator in the thermostat is an electric heater or a semiconductor thermal pile.

[0008] The utility model super-static temperature-controlled liquid cooling source system is also characterized in that: the refrigerant is R410A or R134a refrigerant; the circulating liquid is water or ethylene glycol aqueous solution.

[0009] Compared with the existing technology, the beneficial effects of the utility model are embodied in:

[0010] 1. The utility model designs an ultra-static precision temperature control technology route for two-stage temperature regulation of circulating fluid that is resistant to strong interference dynamic heat load; firstly, the vapor compression refrigeration technology is adopted to accurately adjust the process parameters and cooling capacity of the refrigeration system, and the circulating fluid temperature of the primary adjustment is controlled to the range of TE≥T3≥TE-0.2, with a temperature control accuracy of ±0.1K; at the same time, a thermostat is designed for secondary ultra-static precision regulation to achieve the goal of 10mK level circulating fluid supply temperature accuracy, meeting the technical requirements of temperature accuracy and temperature stability of high-end chip manufacturing equipment.

[0011] 2. The utility model adopts a constant flow rate liquid supply, adopts large flow rate and small temperature difference heat transfer, and the temperature difference between the circulating liquid supply and the return liquid is not more than 2K; the feedforward + feedback control strategy is applied to accurately adjust the energy output of the refrigeration compressor, thereby improving the system's ability to suppress frequent and wide fluctuations in heat load; at the same time, on the basis of controlling the condensing pressure to be relatively stable, the fuzzy adaptive control strategy is applied to adjust the opening of the electronic expansion valve to achieve a circulating liquid outlet temperature accuracy of ±0.1K in one-time regulation; N baffles are arranged in the circulating liquid tank to divide it into N+1 processes, and the circulating liquid passing through the thermostat is rectified and evenly heated in the return flow channel, eliminating the radial gradient of the temperature measurement point, thereby ensuring the measurement accuracy of the circulating liquid supply temperature and the precise regulation of the thermostat.

[0012] 3. The utility model adopts a variable frequency refrigeration compressor, a condenser with variable frequency adjustment of the cooling medium flow, and an electronic expansion valve to construct a regulating mechanism for the refrigeration cycle process parameters and the cooling capacity, designs a constant flow circulating liquid supply method, and solves the problem of precise thermal control of precision mechanical manufacturing equipment such as lithography machines with strong interference dynamic heat loads by precisely measuring and controlling the refrigeration process working parameters and the cooling capacity. Compared with the technical route of using semiconductor refrigeration, the energy efficiency is increased by 5 to 8 times, and the manufacturing cost of the device per unit cooling capacity is reduced by 60 to 80%. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the system flow of the utility model;

[0014] Numbers in the figure: 1 refrigeration compressor, 2 condenser, 4 electronic expansion valve, 5 evaporator, 6 circulating liquid tank, 7 baffle, 8 thermostat, 9 circulating liquid pump. DETAILED DESCRIPTION

[0015] In this embodiment, the ultra-static temperature-controlled liquid cooling source system is composed of a vapor compression refrigeration cycle unit, a circulating liquid constant temperature treatment circuit and a control unit, and is used to provide circulating liquid to the thermal control object.

[0016] like Figure 1 As shown, the vapor compression refrigeration cycle unit is composed of a refrigeration compressor 1, a condenser 2, an electronic expansion valve 4 and an evaporator 5 which are connected in sequence to form a closed refrigerant circulation loop; the condenser 2 is an air-cooled condenser or a water-cooled condenser, and the cooling medium flow of the condenser 2 is adjustable. The condensing fan of the air-cooled condenser is equipped with a variable frequency motor, and the condensing water pump of the water-cooled condenser is equipped with a variable frequency motor; the evaporator 5 is a dual-channel evaporator with an evaporation channel and a cooling channel. The evaporation channel is arranged in the refrigerant circulation loop, and the refrigerant passing through the evaporation channel evaporates and absorbs heat. The cooling channel is arranged in the circulating liquid constant temperature treatment loop, and the circulating liquid passing through the cooling channel releases heat and cools down.

[0017] The circulating liquid constant temperature treatment loop is an open passage that adopts a constant flow liquid supply method, and adopts large flow and small temperature difference heat transfer. The temperature difference between the circulating liquid supply and the return liquid is not more than 2K. The circulating liquid returned from the user end enters the circulating liquid tank 6 after heat release and temperature reduction through the cooling channel of the evaporator 5. The baffle 7 and the thermostat 8 are set in the circulating liquid tank 6. The circulating liquid passing through the circulating liquid tank 6 is temperature-controlled by the thermostat 8, and is rectified and evenly heated by the baffle 7 and then transported to the user end by the circulating liquid pump 9. The circulating liquid absorbs the waste heat of the controlled object at the user end, and the circulating liquid with increased temperature returns from the user end.

[0018] The control unit realizes circulating fluid temperature control through process parameter detection, refrigeration compressor energy control, refrigerant condensing pressure control, refrigerant evaporation temperature control, and circulating fluid ultra-static constant temperature control.

[0019] In specific implementation, the corresponding technical measures also include:

[0020] The refrigerant is R410A or R134a refrigerant; the circulating fluid is ethylene glycol aqueous solution or water, which can be deionized water or purified water.

[0021] There are N baffles 7 arranged in the circulating liquid tank 6, N is not less than 3, and the inner cavity of the circulating liquid tank 6 is divided into N+1 processes by the N baffles 7. The processes from the inlet end of the circulating liquid tank 6 to the outlet end of the circulating liquid tank 6 are the first process, the second process and the subsequent processes respectively. The thermostat 8 is located in the flow channel of the first process or the second process, so that the circulating liquid is temperature-controlled when passing through the thermostat 8, and obtains a rectified uniform temperature when passing through each subsequent process, thereby eliminating the detection error caused by the radial gradient of temperature; the actuator in the thermostat 8 is an electric heater, or a semiconductor thermal pile.

[0022] In this embodiment, setting the corresponding process parameter detection includes:

[0023] Figure 1 As shown, a first temperature sensor T1 and a first pressure sensor P1 are arranged on the refrigerant return air channel between the evaporation channel outlet in the evaporator 5 and the air intake port of the refrigeration compressor 1; the first temperature sensor T1 is used to detect the return air temperature T of the refrigeration compressor 11 , the refrigerant evaporation pressure P0 is detected by the first pressure sensor P1, and the refrigerant evaporation temperature T0 is obtained according to the refrigerant evaporation pressure P0. The refrigerant evaporation temperature T0 refers to the refrigerant saturation temperature T0 corresponding to the refrigerant evaporation pressure P0; the refrigerant vapor superheat T0 at the outlet side of the evaporator 5 is calculated 110 =T 110 =T 11 -T0.

[0024] Figure 1 As shown, a second temperature sensor T2 and a second pressure sensor P2 are arranged on the refrigerant liquid channel between the condenser 2 and the electronic expansion valve 4, and the refrigerant temperature T at the condenser outlet is detected by the second temperature sensor T2. 22 , the refrigerant condensation pressure P is detected by the second pressure sensor P2 k , according to the refrigerant condensation pressure P k Get the refrigerant condensation temperature T k , refrigerant condensation temperature T k It refers to the refrigerant condensation pressure P k The corresponding refrigerant saturation temperature; Calculate the refrigerant subcooling T on the outlet side of the air-cooled condenser (2) k22 =T k22 =T k -T22 .

[0025] Figure 1 As shown, a third temperature sensor T3 is provided on the channel between the cooling channel outlet in the evaporator 5 and the circulating liquid tank 6, and the temperature at the corresponding position is detected by the third temperature sensor T3, which is the circulating liquid outlet temperature T of the evaporator. 33 A fourth temperature sensor T4 is provided at the outlet of the liquid supply pump 9 for detecting the temperature at the corresponding position, which is the circulating liquid supply temperature T 44 A fifth temperature sensor T5 is provided at the entrance of the cooling channel of the evaporator 5 for detecting the temperature at the corresponding position, which is the circulating liquid return temperature T 55 .

[0026] The ultra-static temperature-controlled liquid cooling source system in this embodiment is controlled in the following manner, including:

[0027] The control method for setting the refrigeration compressor energy control is:

[0028] The refrigeration compressor energy controller implements control through feedback control and feedforward control, and according to the fuzzy adaptive control strategy, including: taking the evaporator circulating fluid outlet temperature T 33 As the target parameter, the refrigeration compressor energy controller is used to adjust the input current frequency of the refrigeration compressor 1 so that the evaporator circulating liquid outlet temperature T 33 Reach the temperature target value T3'; set the temperature target value T3' to: T3' = TE-0.1, TE is the circulating liquid supply temperature setting value. Set the feedback control input signal of the refrigeration compressor energy controller to the evaporator circulating liquid outlet temperature deviation value dT 33 and its rate of change dT 33 / dt, where dT 33 =T 33 -T3'. Set the feedforward control input signal of the refrigeration compressor energy controller to the circulating liquid return temperature difference T of the last two detection cycles. 551 -T5 * , where T 551 T5 is the return temperature detection value of the circulating fluid in the current measurement cycle. * It is the detection value of the circulating liquid return temperature in the previous measurement cycle.

[0029] In this embodiment, based on the constant flow rate liquid supply, T 551 -T5 * It is linearly related to the change of heat load of the controlled object. The basis is that when it is applied to a certain controlled object, based on a constant flow circulating liquid pump and a certain object flow resistance, the change of circulating liquid flow can be ignored and the return liquid temperature difference T of the last two times can be directly applied. 551 -T5 *Replace the thermal load fluctuation of the controlled object. This embodiment adds a feedforward control link in the refrigeration compressor energy fuzzy adaptive controller, which can more timely and effectively suppress the thermal load fluctuation of the controlled object, enhance the anti-interference ability of the system, effectively reduce the delay and adjustment time of the control system, and enhance the anti-interference ability of the system.

[0030] In this embodiment, TE-0.1 is used as T 33 The control target is to make the T after the evaporator 33 The temperature variation range is TE≥T3≥TE-0.2, that is, T3≤TE. The thermostat 8 located thereafter only needs the heating function, so an electric heater equipped with a precision power supply can be used, which has a simple structure and low cost. If T3≥TE occurs, the thermostat 8 can be selected as a semiconductor thermal stack with both cold source and heat source functions. A semiconductor thermal stack equipped with a precision power supply can be used. The semiconductor thermal stack can change the direction of the cold end and the hot end by changing the direction of the input current, thereby realizing the switching between cooling and heating.

[0031] The control method for setting the refrigerant condensing pressure control is: the deviation value dP of the refrigerant condensing pressure k and its rate of change dP k / dt is the input signal of the condensing pressure controller. The PID controller is used to adjust and suppress fluctuations. The cooling medium flow of the condenser is adjusted, that is, the air-cooled condenser adjusts the input current frequency of the condensing fan, and the water-cooled condenser adjusts the input current frequency of the condensing water pump to make the refrigerant condensing pressure reach the steady-state value P kw , dP k =P k -P kw , and satisfy T k22 Not less than 5.

[0032] For a certain refrigeration system, that is, when the refrigeration compressor characteristic curve is known, the condenser structure size is determined, the electronic expansion valve characteristic curve is known, and the refrigeration compressor suction pressure and temperature are relatively stable, the condensing pressure of the refrigeration system operation is mainly related to the temperature and flow rate of the cooling medium; under the condition of ensuring the reliable and stable operation of the electronic expansion valve, the lower the condensing pressure, the higher the operating efficiency of the refrigeration system. Through theoretical calculation or experimental research, a reasonable condensing pressure variation range can be obtained. Therefore, the control technology can be optimized to select a better value from it, and the condensing pressure can be controlled to be stable near the better value by adjusting the cooling medium flow of the condenser. In the intelligent control system, learning ability is given, underlying data and experience are accumulated, and iterative optimization is performed to obtain the steady-state value P of the condensing pressure. kwAs the target parameter for the speed control of the variable frequency fan or variable frequency water pump. In addition, for nm-level lithography machines or precision measuring equipment, mechanical manufacturing equipment, they are usually set in a space with constant temperature and humidity control. The external working environment of the ultra-static temperature-controlled liquid cooling source system in this embodiment is relatively stable, and the main disturbance is the thermal load fluctuation of the thermal control object, especially the lithography machine. k22 Not less than 5 is a constraint condition based on the requirement for stable operation of the electronic expansion valve. k22 Under the condition of not less than 5, the lower the refrigerant condensing pressure, the better the system energy saving performance.

[0033] The control method for setting the refrigerant evaporation temperature control is: on the basis of stable condensing pressure, accurately control the superheat of the refrigerant at the evaporator outlet to achieve indirect control of the evaporation temperature, and use the deviation value dT of the refrigerant vapor superheat 110 and its rate of change dT 110 / dt is used as the input signal of the evaporation temperature controller, which uses the fuzzy adaptive control strategy to adjust the opening of the electronic expansion valve 4 to achieve the refrigerant evaporation temperature control, where: dT 110 =T 110 -TG, TG is the set value of refrigerant vapor superheat.

[0034] This embodiment adopts constant flow rate liquid supply, large flow rate, small temperature difference heat transfer, the maximum design temperature difference between supply and return liquid is 2K, and the liquid supply temperature accuracy is ±10mk level. Therefore, the design evaporation temperature is TE-△T. The smaller the setting value of △T, the smaller the average heat transfer temperature difference, and T 33 The smaller the deviation is, the larger the evaporator heat exchange area and volume are required, resulting in excessively high manufacturing costs and excessively large volumes of the evaporator. Regardless of cost or small size and light weight, the value of △T should not be too small. The more suitable value of △T is 1-3K, and the value range of TG is 0.2-0.8K.

[0035] The control method for setting the circulating fluid super-static constant temperature control is: the deviation value dT of the circulating fluid supply temperature 44 and its rate of change dT 44 / dt is used as the input signal of the thermostat 8 and is used by the PID fuzzy controller to control the working voltage of the thermostat 8, where dT 44 =T 44 -TE, in T 33 On the basis of precise regulation, the circulating fluid supply temperature can be adjusted super statically. Therefore, this system adopts the method of secondary temperature adjustment to ensure the stability and accuracy of the circulating fluid supply temperature.

[0036] In this embodiment, the thermostat 8 is composed of an electric heater and a precision power supply. The baffle is set to rectify and equalize the temperature, eliminate the radial temperature gradient of the incoming flow, and use a temperature sensor with a temperature accuracy of not less than ±mK to make the circulating liquid supply temperature T 44 Get accurate measurement and precise circulating fluid supply temperature T 44 ; Circulating fluid supply temperature T 44 Accurate measurement is a necessary condition for the accurate operation of the thermostat 8.

[0037] The ultra-static temperature-controlled liquid cooling source system in this embodiment is mainly used for micro-environment temperature control of precision machining and precision measuring equipment such as nm-level photolithography machines, and provides users with circulating cooling liquid, i.e., circulating liquid, with a temperature accuracy of ±10mK.

[0038] It is easy for those skilled in the art to understand that the above are only preferred embodiments of the present invention, and some conventional functional components, such as the flow switch of the liquid supply pump, the drying filter, the gas-liquid separator, etc., are omitted. Therefore, the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A super-static temperature-controlled liquid cooling source system, characterized by: The system consists of a vapor compression refrigeration cycle unit and a circulating fluid constant temperature treatment circuit; The vapor compression refrigeration cycle unit is composed of a refrigeration compressor (1), a condenser (2), an electronic expansion valve (4) and an evaporator (5) connected in sequence to form a closed refrigerant circulation loop; the condenser (2) is an air-cooled condenser or a water-cooled condenser, the cooling medium flow rate of the condenser (2) is adjustable, the condensing fan of the air-cooled condenser is equipped with a variable frequency motor, and the condensing water pump of the water-cooled condenser is equipped with a variable frequency motor; the evaporator (5) is a dual-channel evaporator having an evaporation channel and a cooling channel, the evaporation channel is arranged in the refrigerant circulation loop, the refrigerant passing through the evaporation channel evaporates and absorbs heat, the cooling channel is arranged in the circulating liquid constant temperature treatment loop, and the circulating liquid passing through the cooling channel releases heat and cools down; The circulating liquid constant temperature treatment circuit is an open passage for supplying liquid at a constant flow rate. The circulating liquid returned from the user end is cooled by heat release in the cooling channel of the evaporator (5) and then enters the circulating liquid tank (6). A baffle (7) and a thermostat (8) are arranged in the circulating liquid tank (6). The circulating liquid passing through the circulating liquid tank (6) is temperature-controlled by the thermostat (8), and after being rectified and evenly heated by the baffle (7), it is transported to the user end by the circulating liquid pump (9).

2. The ultra-static temperature-controlled liquid cooling source system according to claim 1 is characterized in that: There are N baffles (7) arranged in the circulating liquid tank (6), N is not less than 3, and the inner cavity of the circulating liquid tank (6) is divided into N+1 processes by the N baffles (7). The processes from the inlet end of the circulating liquid tank (6) toward the outlet end of the circulating liquid tank (6) are successively the first process, the second process and each subsequent process. The thermostat (8) is located in the flow channel of the first process or the second process, so that the circulating liquid is temperature-controlled when passing through the thermostat (8) and obtains a rectified uniform temperature when passing through each subsequent process, thereby eliminating the detection error caused by the radial temperature gradient.

3. The ultra-static temperature-controlled liquid cooling source system according to claim 1 is characterized in that: The actuator in the thermostat (8) is an electric heater or a semiconductor thermal pile.

4. The ultra-static temperature-controlled liquid cooling source system according to claim 1 is characterized in that: The refrigerant is R410A or R134a; the circulating fluid is water or ethylene glycol aqueous solution.

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