Patent Publication Number: US-2023147288-A1

Title: Temperature control system

Description:
FIELD 
     The present disclosure relates to a temperature control system. 
     BACKGROUND 
     In a technical field related to semiconductor manufacturing apparatuses, temperature control systems that control the temperature of a temperature control target by circulating fluid as the one disclosed in Patent Literature 1 are used. Patent Literature 1 describes a method of obtaining a target temperature by mixing feed fluid from an external high-temperature chiller and a low-temperature chiller with fluid in circulation by using a mixing valve in order to change the target temperature as quickly as possible during the process. 
     CITATION LIST 
     Patent Literature 
     
         
         Patent Literature 1: JP 2013-105359 A 
       
    
     SUMMARY 
     Technical Problem 
     However, in the method disclosed in Patent Literature 1, although the dynamic characteristics of the mixing valve are high gain and high response, there is a problem that temperature controllability is poor and hunting is likely to occur due to nonlinearity between the valve opening degree of the mixing valve and the flow rate, a dead zone of the valve opening, nonlinear elements such as hysteresis, a low response of a temperature control target, dead time of the temperature control target, and the like. 
     An object of the present disclosure is to control the temperature of fluid with high accuracy. 
     Solution to Problem 
     According to an aspect of the present invention, a temperature control system, comprises: a circulation flow path that includes a temperature control target, the circulation flow path through which fluid flows; a first temperature control device that adjusts a temperature of the fluid in a first portion of the circulation flow path by supplying, to the first portion, at least one of the fluid having a first temperature or the fluid having a second temperature higher than the first temperature; a second temperature control device that adjusts the temperature of the fluid supplied to the temperature control target at a second portion of the circulation flow path between the first portion and the temperature control target; a first temperature sensor that detects the temperature of the fluid supplied from the first portion to the second portion; a second temperature sensor that detects the temperature of the fluid or the temperature control target at a predetermined position in the circulation flow path between an outlet of the second portion and an inlet of the first portion; a first controller that controls the first temperature control device on a basis of a detection value of the first temperature sensor such that the temperature of the fluid supplied from the first portion to the second portion becomes a first target temperature; and a second controller that controls the second temperature control device on a basis of a detection value of the second temperature sensor such that the temperature of the fluid becomes a second target temperature at the predetermined position, wherein the first target temperature is determined on a basis of the second target temperature. 
     Advantageous Effects of Invention 
     According to the present disclosure, the temperature of fluid can be controlled with high accuracy. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a configuration diagram illustrating a temperature control system according to a first embodiment. 
         FIG.  2    is a diagram schematically illustrating a second temperature control device according to the first embodiment. 
         FIG.  3    is an enlarged cross-sectional view of a part of a temperature control unit according to the first embodiment. 
         FIG.  4    is a block diagram illustrating a temperature control system according to the first embodiment. 
         FIG.  5    is a graph for explaining a specified value according to the first embodiment. 
         FIG.  6    is a block diagram illustrating a temperature control system according to a second embodiment. 
         FIG.  7    is a block diagram illustrating a temperature control system according to a third embodiment. 
         FIG.  8    is a block diagram illustrating a temperature control system according to a fourth embodiment. 
         FIG.  9    is a block diagram illustrating a temperature control system according to a fifth embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments of the present disclosure will be described with reference to the drawings; however, the present disclosure is not limited thereto. Components of the embodiments described below can be combined as appropriate. Moreover, some of the components may not be used. 
     First Embodiment 
     &lt;Overview of Temperature Control System&gt; 
       FIG.  1    is a configuration diagram illustrating a temperature control system  1  according to the present embodiment. As illustrated in  FIG.  1   , the temperature control system  1  includes a circulation flow path  2  that includes a temperature control target S and through which fluid F flows, a first temperature control device  3  that adjusts the temperature of the fluid F in a first portion  2 A of the circulation flow path  2 , a second temperature control device  4  that adjusts the temperature of the fluid F in a second portion  2 B of the circulation flow path  2  between the first portion  2 A and the temperature control target S, a pump  5  that causes the fluid F to flow in the circulation flow path  2 , a temperature sensor  6  that detects the temperature of the fluid F, a first controller  7  that controls the first temperature control device  3 , and a second controller  8  that controls the second temperature control device  4 . 
     The temperature control target S includes at least a part of a semiconductor manufacturing apparatus. The temperature control target S includes, for example, a wafer holder of a plasma processing apparatus. The wafer holder holds a semiconductor wafer subjected to plasma processing in the plasma processing apparatus. The wafer holder is made of, for example, aluminum. The wafer holder includes an electrostatic chuck that holds a semiconductor wafer with electrostatic adsorption power. The electrostatic chuck adsorbs and holds the semiconductor wafer by Coulomb force when a DC voltage is applied. By controlling the temperature of the wafer holder, the temperature of the semiconductor wafer held by the wafer holder is adjusted. 
     The temperature control system  1  controls the temperature of the temperature control target S by supplying the fluid F to the temperature control target S. In the present embodiment, the fluid F is liquid. Note that the fluid F may be gas. In the circulation flow path  2 , the fluid F is supplied from the first temperature control device  3  to the second temperature control device  4  and then supplied to the temperature control target S. The fluid F supplied to the temperature control target S is returned to the first temperature control device  3 . 
     The temperature control target S has an inlet Ma into which the fluid F from the second temperature control device  4  flows and an outlet Mb from which the fluid F flows out. The first temperature control device  3  has an inlet Mc into which the fluid F from the temperature control target S flows and an outlet Md from which the fluid F flows out. The second temperature control device  4  has an inlet Me into which the fluid F from the first temperature control device  3  flows and an outlet Mf from which the fluid F flows out. The inlet Mc of the first temperature control device  3  is also an inlet of the first portion  2 A. The outlet Md of the first temperature control device  3  is also an outlet of the first portion  2 A. The inlet Me of the second temperature control device  4  is also an inlet of the second portion  2 B. The outlet Mf of the second temperature control device  4  is also an outlet of the second portion  2 B. 
     The first temperature control device  3  is a so-called rough temperature control device. The second temperature control device  4  is a so-called fine temperature control device. The temperature adjustable range (gain) by the first temperature control device  3  is wider than the temperature adjustable range by the second temperature control device  4 . As an example, the temperature adjustable range by the first temperature control device  3  is ±50° C., and the temperature adjustable range by the second temperature control device  4  is ±1° C. The response speed (responsiveness) of the second temperature control device  4  is higher than the response speed of the first temperature control device  3 . The response speed refers to a time required for the temperature of the fluid F to reach a target temperature. A high response speed means that the time required for the temperature of the fluid F to reach a target temperature is short. A low response speed means that the time required for the temperature of the fluid F to reach a target temperature is long. 
     A tank  9  is disposed in the circulation flow path  2 . In the embodiment, the first portion  2 A includes the tank  9  disposed in the circulation flow path  2 . The inlet Mc and the outlet Md are included in the tank  9 . 
     The first temperature control device  3  supplies at least one of the fluid F having a first temperature T L  or the fluid F having a second temperature T H  higher than the first temperature T L  to the tank  9  of the circulation flow path  2  to adjust the temperature of the fluid F in the tank  9 . The first temperature control device  3  roughly adjusts the temperature of the fluid F. 
     The second temperature control device  4  adjusts the temperature of the fluid F supplied to the temperature control target S in the second portion  2 B of the circulation flow path  2  between the tank  9  and the temperature control target S. The second temperature control device  4  adjusts the temperature of the fluid F with high accuracy. 
     The pump  5  is disposed in the circulation flow path  2  between the tank  9  and the second temperature control device  4 . When the pump  5  is driven, the fluid F circulates in the circulation flow path  2 . 
     The temperature sensor  6  includes a first temperature sensor  61  that detects a temperature T 1  of the fluid F supplied from the first portion  2 A to the second portion  2 B and a second temperature sensor  62  that detects a temperature T 2  of the temperature control target S or the fluid F or at a predetermined position in the circulation flow path  2  between the outlet Mf of the second portion  2 B (second temperature control device  4 ) and the inlet Mc of the first portion  2 A (first temperature control device  3 ). 
     The predetermined position of the circulation flow path  2  where the temperature T 2  of the fluid F is detected by the second temperature sensor  62  includes a first predetermined position P 1  set between the second portion  2 B and the temperature control target S and a second predetermined position P 2  and a third predetermined position P 3  set between the inlet Ma of the temperature control target S and the inlet Mc of the first portion  2 A. The second temperature sensor  62  includes a second temperature sensor  62 A that detects a temperature T 2   a  of the fluid F at the first predetermined position P 1  set between the second portion  2 B and the temperature control target S, a second temperature sensor  62 B that detects a temperature T 2   b  of the temperature control target S at the second predetermined position P 2  set in the temperature control target S, and a second temperature sensor  62 C that detects a temperature T 2   c  of the fluid F at the third predetermined position P 3  set between the temperature control target S and the first portion  2 A. 
     &lt;First Temperature Control Device&gt; 
     The first temperature control device  3  includes a low-temperature control unit  10 L that stores the fluid F having the first temperature T L , a high-temperature control unit  10 H that stores the fluid F having the second temperature T H  higher than the first temperature T L , a low-temperature flow path  11 L through which the fluid F supplied from the low-temperature control unit  10 L to the tank  9  flows, a high-temperature flow path  11 H through which the fluid F supplied from the high-temperature control unit  10 H to the tank  9  flows, a low-temperature overflow channel  12 L through which the fluid F returned from the tank  9  to the low-temperature control unit  10 L flows, a high-temperature overflow channel  12 H through which the fluid F returned from the tank  9  to the high-temperature control unit  10 H flows, and a valve system  13  that adjusts a flow rate of the fluid F flowing through the low-temperature flow path  11 L and a flow rate of the fluid flowing through the high-temperature flow path  11 H. 
     The low-temperature control unit  10 L stores the fluid F having the first temperature T L . The low-temperature control unit  10 L can send the fluid F having the first temperature T L  to the tank  9 . The low-temperature control unit  10 L includes a low-temperature tank, a low-temperature controller, and a low-temperature pump that sends out the fluid F. The low-temperature controller includes a heat exchanger. The low-temperature controller adjusts the temperature of the fluid F to the first temperature T L . The fluid F adjusted to the first temperature T L  is stored in the low-temperature tank. As an example, the first temperature T L  is 5° C. 
     The high-temperature control unit  10 H stores the fluid F having the second temperature T H  higher than the first temperature T L . The high-temperature control unit  10 H can send the fluid F having the second temperature T H  to the tank  9 . The high-temperature control unit  10 H includes a high-temperature tank, a high-temperature controller, and a high-temperature pump that sends out the fluid F. The high-temperature controller includes a heat exchanger. The high-temperature controller adjusts the temperature of the fluid F to the second temperature T H . The fluid F adjusted to the second temperature T H  is stored in the high-temperature tank. As an example, the second temperature T H  is 90° C. 
     The low-temperature flow path  11 L connects the low-temperature control unit  10 L and the tank  9 . The low-temperature control unit  10 L can supply the fluid F having the first temperature T L  to the tank  9  via the low-temperature flow path  11 L. The fluid F supplied from the low-temperature control unit  10 L to the tank  9  flows through the low-temperature flow path  11 L. 
     The high-temperature flow path  11 H connects the high-temperature control unit  10 H and the tank  9 . The high-temperature control unit  10 H can supply the fluid F having the second temperature T H  to the tank  9  via the high-temperature flow path  11 H. The fluid F supplied from the high-temperature control unit  10 H to the tank  9  flows through the high-temperature flow path  11 H. 
     The valve system  13  can switch among a first state in which the fluid F is supplied neither from the low-temperature control unit  10 L nor the high-temperature control unit  10 H to the tank  9 , a second state in which the fluid F is supplied from the low-temperature control unit  10 L to the tank  9 , and a third state in which the fluid F is supplied from the high-temperature control unit  10 H to the tank  9 . The first state is a state in which the fluid F is supplied neither from the low-temperature control unit  10 L nor the high-temperature control unit  10 H to the tank  9 . The second state is a state in which the fluid F at the first temperature T L  is supplied from the low-temperature control unit  10 L to the tank  9  and the fluid F is not supplied from the high-temperature control unit  10 H to the tank  9 . The third state is a state in which the fluid F at the second temperature T H  is supplied from the high-temperature control unit  10 H to the tank  9  and the fluid F is not supplied from the low-temperature control unit  10 L to the tank  9 . 
     In addition, the valve system  13  can switch among a fourth state in which the fluid F is returned, from the tank  9 , to neither the low-temperature control unit  10 L nor the high-temperature control unit  10 H, a fifth state in which the fluid F is returned from the tank  9  to the low-temperature control unit  10 L, and a sixth state in which the fluid F is returned from the tank  9  to the high-temperature control unit  10 H. The fourth state is a state in which the fluid F not returned from the tank  9  to neither the low-temperature control unit  10 L nor the high-temperature control unit  10 H. The fifth state is a state in which the fluid F is returned from the tank  9  to the low-temperature control unit  10 L and the fluid F is not returned from the tank  9  to the high-temperature control unit  10 H. The sixth state is a state in which the fluid F is returned from the tank  9  to the high-temperature control unit  10 H and the fluid F is not returned from the tank  9  to the low-temperature control unit  10 L. 
     The valve system  13  is controlled by the first controller  7 . The first controller  7  controls the valve system  13  of the first temperature control device  3  on the basis of a detection value of the first temperature sensor  61  so that the temperature of the fluid F supplied from the first portion  2 A (tank  9 ) to the second portion  2 B (second temperature control device  4 ) becomes a first target temperature SV 1 . The valve system  13  controls the valve system  13  so that the fluid F in the tank  9  becomes the first target temperature SV 1  and adjusts the flow rate of the fluid F flowing through the low-temperature flow path  11 L from the low-temperature control unit  10 L toward the tank  9  and the flow rate of the fluid F flowing through the high-temperature flow path  11 H from the high-temperature control unit  10 H toward the tank  9 . 
     The valve system  13  includes a low-temperature flow rate adjusting valve  14 L disposed in the low-temperature flow path  11 L, a high-temperature flow rate adjusting valve  14 H disposed in the high-temperature flow path  11 H, a low-temperature on-off valve  15 L disposed in the low-temperature overflow channel  12 L, and a high-temperature on-off valve  15 H disposed in the high-temperature overflow channel  12 H. 
     The low-temperature flow rate adjusting valve  14 L is controlled by the first controller  7 . The first controller  7  can switch between supply and stop of the fluid F from the low-temperature control unit  10 L to the tank  9  and adjust the flow rate of the fluid F supplied from the low-temperature control unit  10 L to the tank  9  by controlling the low-temperature flow rate adjusting valve  14 L. When the low-temperature flow rate adjusting valve  14 L is opened, the fluid F at the first temperature T L  is supplied from the low-temperature control unit  10 L to the tank  9 . When the low-temperature flow rate adjusting valve  14 L is closed, the supply of the fluid F from the low-temperature control unit  10 L to the tank  9  is stopped. 
     The high-temperature flow rate adjusting valve  14 H is controlled by the first controller  7 . The first controller  7  can switch between supply and stop of the fluid F from the high-temperature control unit  10 H to the tank  9  and adjust the flow rate of the fluid F supplied from the high-temperature control unit  10 H to the tank  9  by controlling the high-temperature flow rate adjusting valve  14 H. When the high-temperature flow rate adjusting valve  14 H is opened, the fluid F at the second temperature T H  is supplied from the high-temperature control unit  10 H to the tank  9 . When the high-temperature flow rate adjusting valve  14 H is closed, the supply of the fluid F from the high-temperature control unit  10 H to the tank  9  is stopped. 
     The low-temperature flow rate adjusting valve  14 L may be a proportional valve or an on-off valve. A proportional valve can perform flow rate control of the fluid F with high accuracy. Therefore, in a case where a proportional valve is used as the low-temperature flow rate adjusting valve  14 L, the temperature control of the fluid F in the tank  9  can be performed with high accuracy. Note that in a case where highly accurate flow rate control of the fluid F or highly accurate temperature control of the fluid F in the tank  9  is not required, an inexpensive on-off valve may be used as the low-temperature flow rate adjusting valve  14 L. Similarly, the high-temperature flow rate adjusting valve  14 H may be a proportional valve or an on-off valve. 
     The low-temperature on-off valve  15 L is an on-off valve. When the low-temperature on-off valve  15 L is opened, the fluid F is returned from the tank  9  to the low-temperature control unit  10 L. When the low-temperature on-off valve  15 L is closed, the fluid F is not returned from the tank  9  to the low-temperature control unit  10 L. The on-off valve is, for example, an electromagnetic valve. 
     The high-temperature on-off valve  15 H is an on-off valve. When the high-temperature on-off valve  15 H is opened, the fluid F is returned from the tank  9  to the high-temperature control unit  10 H. When the high-temperature on-off valve  15 H is closed, the fluid F is not returned from the tank  9  to the high-temperature control unit  10 H. The on-off valve is, for example, an electromagnetic valve. 
     The first controller  7  closes both of the low-temperature flow rate adjusting valve  14 L and the high-temperature flow rate adjusting valve  14 H when bringing the flowing state of the fluid F to the first state. As a result, the fluid F is not supplied to the tank  9  from each of the low-temperature control unit  10 L and the high-temperature control unit  10 H. 
     The first controller  7  opens the low-temperature flow rate adjusting valve  14 L and closes the high-temperature flow rate adjusting valve  14 H when bringing the flowing state of the fluid F to the second state. As a result, the fluid F at the first temperature T L  sent from the low-temperature control unit  10 L is supplied to the tank  9  at a prescribed flow rate via the low-temperature flow path  11 L. 
     The first controller  7  opens the high-temperature flow rate adjusting valve  14 H and closes the low-temperature flow rate adjusting valve  14 L when bringing the flowing state of the fluid F to the third state. As a result, the fluid F at the second temperature T H  sent from the high-temperature control unit  10 H is supplied to the tank  9  at a prescribed flow rate via the high-temperature flow path  11 H. 
     The first controller  7  closes each of the low-temperature on-off valve  15 L and the high-temperature on-off valve  15 H when bringing the flowing state of the fluid F to the fourth state. As a result, the fluid F is not returned from the tank  9  to either the low-temperature control unit  10 L or the high-temperature control unit  10 H. 
     The first controller  7  opens the low-temperature on-off valve  15 L and closes the high-temperature on-off valve  15 H when bringing the flowing state of the fluid F to the fifth state. As a result, at least a part of the fluid F stored in the tank  9  is returned to the low-temperature control unit  10 L via the low-temperature overflow channel  12 L. 
     The first controller  7  opens the high-temperature on-off valve  15 H and closes the low-temperature on-off valve  15 L when bringing the flowing state of the fluid F to the sixth state. As a result, at least a part of the fluid F stored in the tank  9  is returned to the high-temperature control unit  10 H via the high-temperature overflow channel  12 H. 
     &lt;Second Temperature Control Device&gt; 
       FIG.  2    is a diagram schematically illustrating the second temperature control device  4  according to the present embodiment. The second temperature control device  4  includes thermoelectric modules  60 . As illustrated in  FIG.  2   , the second temperature control device  4  includes a body member  40  having a temperature control flow path  42 , a temperature control unit  50  having the thermoelectric modules  60  connected to the body member  40 , a heat exchange plate  44  connected to the temperature control unit  50 , and a drive circuit  45  that drives the temperature control unit  50 . 
     The temperature control flow path  42  is included inside the body member  40 . The fluid F from the tank  9  flows into the temperature control flow path  42  via the inlet Me. The fluid F having flowed through the temperature control flow path  42  flows out of the temperature control flow path  42  via the outlet Mf. The fluid F flowed out of the temperature control flow path  42  is supplied to the temperature control target S. 
     The temperature control unit  50  adjusts the temperature of the fluid F flowing through the temperature control flow path  42  via the body member  40 . The temperature control unit  50  includes the thermoelectric modules  60 . The temperature control unit  50  adjusts the temperature of fluid F using the thermoelectric modules  60 . 
     The thermoelectric modules  60  absorb heat or generate heat to adjust the temperature of the fluid F flowing through the temperature control flow path  42 . The thermoelectric modules  60  absorb heat or generate heat by supplying electric power. The thermoelectric modules  60  absorb heat or generate heat by the Peltier effect. 
     The heat exchange plate  44  exchanges heat with the temperature control unit  50 . The heat exchange plate  44  has an internal flow path (not illustrated) through which a temperature control medium flows. The temperature control medium flows into the internal flow path of the heat exchange plate  44  after being temperature-regulated by a medium temperature controlling device (not illustrated). The temperature control medium flows through the internal flow path and thereby takes heat from the heat exchange plate  44  or provides heat to the heat exchange plate  44 . The temperature control medium flows out of the internal flow path and is returned to the fluid temperature control device. 
       FIG.  3    is an enlarged cross-sectional view of a part of the temperature control unit  50  according to the present embodiment. As illustrated in  FIG.  3   , the temperature control unit  50  includes a plurality of thermoelectric modules  60  and a case  51  accommodating the plurality of thermoelectric modules  60 . One end face of the case  51  is connected with the body member  40 . The other end face of the case  51  is connected with the heat exchange plate  44 . 
     A thermoelectric module  60  includes a first electrode  65 , second electrodes  66 , and thermoelectric semiconductor elements  63 . The thermoelectric semiconductor elements  63  includes a p-type thermoelectric semiconductor element  63 P and an n-type thermoelectric semiconductor element  63 N. The first electrode  65  is connected to each of the p-type thermoelectric semiconductor element  63 P and the n-type thermoelectric semiconductor element  63 N. The second electrodes  66  are each connected to one of the p-type thermoelectric semiconductor element  63 P and the n-type thermoelectric semiconductor element  63 N. The first electrode  65  is adjacent to the body member  40 . The second electrodes  66  are adjacent to the heat exchange plate  44 . One end face of the p-type thermoelectric semiconductor element  63 P and one end face of the n-type thermoelectric semiconductor element  63 N are each connected to the first electrode  65 . The other end face of the p-type thermoelectric semiconductor element  63 P and the other end face of the n-type thermoelectric semiconductor element  63 N are each connected to one of the second electrodes  66 . 
     The thermoelectric modules  60  absorb heat or generate heat by the Peltier effect. The drive circuit  45  supplies, to the thermoelectric modules  60 , electric power for causing the thermoelectric modules  60  to absorb heat or to generate heat. The drive circuit  45  applies a potential difference between the first electrode  65  and the second electrodes  66 . When a potential difference is applied between the first electrode  65  and the second electrodes  66 , electric charges are transferred in the thermoelectric semiconductor elements  63 . The transfer of electric charges causes transfer of heat in the thermoelectric semiconductor elements  63 . As a result, the thermoelectric module  60  absorbs heat or generates heat. For example, when a potential difference is applied between the first electrodes  65  and the second electrodes  66  so that the first electrodes  65  generate heat and the second electrodes  66  absorb heat, the fluid F flowing through the temperature control flow path  42  is heated. When a potential difference is applied between the first electrodes  65  and the second electrodes  66  so that the first electrodes  65  absorb heat and the second electrodes  66  generate heat, the fluid F flowing through the temperature control flow path  42  is cooled. 
     The drive circuit  45  applies electric power (potential difference) to the thermoelectric modules  60 . The drive circuit  45  is controlled by the second controller  8 . The second controller  8  controls the thermoelectric modules  60  by controlling the drive circuit  45 . The amount of heat absorbed or generated by thermoelectric modules  60  is adjusted through adjustment of the electric power supplied to thermoelectric modules  60 . The temperature of the fluid F flowing through the temperature control flow path  42  is adjusted through adjustment of the amount of heat absorbed or generated by the thermoelectric modules  60 . 
     The second controller  8  controls the thermoelectric modules  60  of the second temperature control device  4  on the basis of a detection value of the second temperature sensor  62  so that the temperature of the fluid F becomes the second target temperature SV 2  at a predetermined position in the circulation flow path  2 . 
     &lt;Control Method&gt; 
       FIG.  4    is a block diagram illustrating the temperature control system  1  according to the present embodiment. In the present embodiment, a control method for bringing the temperature of the fluid F at the first predetermined position P 1  between the second temperature control device  4  and the temperature control target S to the second target temperature SV 2  will be described. 
     As illustrated in  FIG.  4   , the temperature control system  1  includes: the circulation flow path  2  including the temperature control target S; the first temperature control device  3  that supplies at least one of the fluid F having the first temperature T L  and the fluid F having the second temperature T H  higher than the first temperature T L  to the first portion  2 A of the circulation flow path  2  to adjust the temperature of the fluid F in the first portion  2 A; the second temperature control device  4  that adjusts the temperature of the fluid F supplied to the temperature control target S in the second portion  2 B of the circulation flow path  2  between the first portion  2 A and the temperature control target S; the first temperature sensor  61  that detects the temperature of the fluid F supplied from the first portion  2 A to the second portion  2 B; the second temperature sensor  62 A that detects the temperature of the fluid F at the first predetermined position P 1  in the circulation flow path  2  between the second portion  2 B and the temperature control target S; the first controller  7  that controls the first temperature control device  3  so that the temperature of the fluid F supplied from the first portion  2 A to the second portion  2 B becomes the first target temperature SV 1  on the basis of a detection value of the first temperature sensor  61 ; and the second controller  8  that controls the second temperature control device  4  so that the temperature of the fluid F becomes the second target temperature SV 2  at the first predetermined position P 1  in the circulation flow path  2  between the second portion  2 B and the temperature control target S on the basis of the detection value of the second temperature sensor  62 A. 
     The first temperature control device  3  and the second temperature control device  4  are connected in series in the circulation flow path  2 . The outlet Mf of the second temperature control device  4  is connected to the inlet Ma of the temperature control target S via the flow path of the circulation flow path  2 . The outlet Mb of the temperature control target S is connected to the inlet Mc of the first temperature control device  3  via the flow path of the circulation flow path  2 . 
     The response speed of the first temperature control device  3  is slower than the response speed of the temperature control target S. The response speed of the second temperature control device  4  is faster than the response speed of the temperature control target S. The temperature controllable range of the first temperature control device  3  is larger than the temperature controllable range of the second temperature control device  4 . 
     In a case where the temperature control target S is a wafer holder of a plasma processing apparatus, the temperature control target S receives thermal disturbance due to plasma. When the temperature control target S receives thermal disturbance, the temperature of the fluid F in at least a part of the circulation flow path  2  may increase. The temperature control system  1  suppresses fluctuation of the temperature of the fluid F even when the temperature control target S receives thermal disturbance. 
     The first controller  7  feedback-controls the first temperature control device  3  on the basis of a detection value of the first temperature sensor  61  so that the temperature of the fluid F flowing out of the first temperature control device  3  becomes the first target temperature SV 1 . That is, the first controller  7  feeds back the temperature T 1  which is the detection value of the first temperature sensor  61 , calculates a manipulated variable MV 1  from a deviation from the first target temperature SV 1 , and controls the first temperature control device  3  on the basis of the manipulated variable MV 1 . 
     The second controller  8  feedback-controls the second temperature control device  4  on the basis of a detection value of the second temperature sensor  62 A so that the temperature of the fluid F flowing out of the second temperature control device  4  becomes the second target temperature SV 2 . That is, the second controller  8  feeds back the temperature T 2   a  which is the detection value of the second temperature sensor  62 A, calculates a manipulated variable MV 2  from a deviation from the second target temperature SV 2 , and controls the second temperature control device  4  on the basis of the manipulated variable MV 2 . 
     The temperature of the fluid F controlled by the first controller  7  is a so-called outlet temperature of the first temperature control device  3 . Note that the temperature of the fluid F controlled by the first controller  7  may be regarded as a so-called inlet temperature of the second temperature control device  4 . 
     The temperature of the fluid F controlled by the second controller  8  is a so-called inlet temperature of the temperature control target S. Note that the temperature of the fluid F controlled by the second controller  8  may be regarded as a so-called outlet temperature of the second temperature control device  4 . 
     The second target temperature SV 2  is a target temperature of the temperature control target S. The target temperature of the temperature control target S is to be changed. In a case where the temperature control target S is a wafer holder of a plasma processing apparatus, the target temperature of the temperature control target S is determined on the basis of the process of plasma processing. The target temperature of the temperature control target S is changed during the plasma processing process such as 20° C., 60° C., or 80° C. 
     In the present embodiment, the first target temperature SV 1  is determined on the basis of the second target temperature SV 2 . The first target temperature SV 1  is a function of the second target temperature SV 2 . 
     The second controller  8  determines the first target temperature SV 1  on the basis of the second target temperature SV 2  and outputs the first target temperature SV 1  to the first controller  7 . Note that the first target temperature SV 1  may be determined by the first controller  7 . 
     In the present embodiment, the first target temperature SV 1  is determined on the basis of the second target temperature SV 2  and a specified value α related to the temperature control capability of the second temperature control device  4 . The specified value α is zero or a positive value (α≥0). In the present embodiment, [SV 1 =SV 2 −α]. 
     In the present embodiment, the second temperature control device  4  includes the thermoelectric modules  60 . The temperature adjustable range of the thermoelectric modules  60  is wide at low temperatures and narrow at high temperatures. The specified value α is set to a larger value as the second target temperature SV 2  is lower and is set to a smaller value as the second target temperature SV 2  is higher. 
       FIG.  5    is a graph for explaining the specified value α according to the embodiment. As illustrated in  FIG.  5   , the specified value α is set so as to decrease as the second target temperature SV 2  increases. For example, in a case where the second target temperature SV 2  is 20° C., the specified value α is determined to be a value α 1 . In a case where the second target temperature SV 2  is 80° C., the specified value α is determined to be a value α 2  smaller than the value α 1 . The relationship between the specified value α and the second target temperature SV 2  is known data determined on the basis of the temperature control capability (specification) of the second temperature control device  4 . 
     In a case where the second target temperature SV 2  is 20° C., the first target temperature SV 1  is [SV 2 −α 1 ]. In a case where the second target temperature SV 2  is 80° C., the first target temperature SV 1  is [SV 2 −α 2 ]. A relationship of [SV 2 −α 1 ]&lt;[SV 2 −α 2 ] holds. The lower the second target temperature SV 2  is, the larger the difference between the first target temperature SV 1  and the second target temperature SV 2  is. The higher the second target temperature SV 2  is, the smaller the difference between the first target temperature SV 1  and the second target temperature SV 2  is. That is, as the second target temperature SV 2  is lower, the temperature of the fluid F adjusted by the first temperature control device  3  may be more far from the second target temperature SV 2  (target temperature of the temperature control target S). As the second target temperature SV 2  is higher, the temperature of the fluid F adjusted by the first temperature control device  3  needs to be closer to the second target temperature SV 2  (target temperature of the temperature control target S). 
     Since the temperature adjustable range of the thermoelectric module  60  is large in a case where the second target temperature SV 2  is low, the second temperature control device  4  can adjust the temperature of the fluid F supplied from the first temperature control device  3  to the second target temperature SV 2  even in a case where the temperature of the fluid F adjusted by the first temperature control device  3  is far from the second target temperature SV 2 . 
     Since the temperature of the fluid F adjusted by the first temperature control device  3  approaches the second target temperature SV 2  in a case where the second target temperature SV 2  is high, the second temperature control device  4  can adjust the fluid F supplied from the first temperature control device  3  to the second target temperature SV 2  even in a case where the temperature adjustable range of the thermoelectric modules  60  is narrow. 
     &lt;Effects&gt; 
     As described above, according to the present embodiment, in a case where the temperature of the temperature control target S is adjusted by the fluid F circulating in the circulation flow path  2 , the first temperature control device  3  and the second temperature control device  4  are provided in the circulation flow path  2 . As a result, the temperature control system  1  can control the temperature of the fluid F with high accuracy. 
     As described above, the target temperature (second target temperature SV 2 ) of the temperature control target S may be changed during the process. When the target temperature of the temperature control target S is changed, the first temperature control device  3  having a wide temperature adjustable range adjusts the temperature of the fluid F close to the target temperature of the temperature control target S, and the second temperature control device  4  having a high response speed finely adjusts the temperature of the fluid F to stabilize the temperature to the target temperature of the temperature control target S. As a result, the temperature of the fluid F supplied to the temperature control target S is controlled to the target temperature of the temperature control target S with high accuracy. In addition, in a case where the temperature control target S receives thermal disturbance, the first temperature control device  3  can attenuate the fluctuation of the temperature of the fluid F, and the second temperature control device  4  can finely adjust the temperature of the fluid F. 
     The first target temperature SV 1  is determined on the basis of the second target temperature SV 2  and the specified value α. As a result, the second temperature control device  4  can appropriately finely adjust the temperature of the fluid F. 
     Second Embodiment 
     A second embodiment will be described. In the following description, the same or equivalent components as those of the above embodiment are denoted by the same symbols, and description thereof is simplified or omitted. 
       FIG.  6    is a block diagram illustrating a temperature control system  1  according to the present embodiment. In the present embodiment, a control method for bringing the temperature of the fluid F at the temperature control target S at the second predetermined position P 2  between the inlet Ma of the temperature control target S and the inlet Mc of the first temperature control device  3  or at the third predetermined position P 3  to the second target temperature SV 2  will be described. The second predetermined position P 2  is set at the temperature control target S. The third predetermined position P 3  is set between the outlet Mb of the temperature control target S and the inlet Mc of the first temperature control device  3 . Hereinafter, a control method for bringing the temperature of the fluid F at the third predetermined position P 3  to the second target temperature SV 2  will be described. Note that a control method for bringing the temperature of the temperature control target S at the second predetermined position P 2  to the second target temperature SV 2  is similar. 
     As illustrated in  FIG.  6   , the temperature control system  1  includes: the circulation flow path  2  including the temperature control target S; the first temperature control device  3  that supplies at least one of the fluid F having the first temperature T L  and the fluid F having the second temperature T H  higher than the first temperature T L  to the first portion  2 A of the circulation flow path  2  to adjust the temperature of the fluid F in the first portion  2 A; the second temperature control device  4  that adjusts the temperature of the fluid F supplied to the temperature control target S in the second portion  2 B of the circulation flow path  2  between the first portion  2 A and the temperature control target S; the first temperature sensor  61  that detects the temperature of the fluid F supplied from the first portion  2 A to the second portion  2 B; the second temperature sensor  62 C that detects the temperature of the fluid F at the third predetermined position P 3  in the circulation flow path  2  between the temperature control target S and the first temperature control device  3 ; the first controller  7  that controls the first temperature control device  3  so that the temperature of the fluid F supplied from the first portion  2 A to the second portion  2 B becomes the first target temperature SV 1  on the basis of a detection value of the first temperature sensor  61 ; and the second controller  8  that controls the second temperature control device  4  so that the temperature of the fluid F becomes the second target temperature SV 2  at the third predetermined position P 3  in the circulation flow path  2  between the temperature control target S and the first temperature control device  3  on the basis of a detection value of the second temperature sensor  62 C. 
     The first controller  7  feedback-controls the first temperature control device  3  on the basis of a detection value of the first temperature sensor  61  so that the temperature of the fluid F flowing out of the first temperature control device  3  becomes the first target temperature SV 1 . That is, the first controller  7  feeds back the temperature T 1  which is the detection value of the first temperature sensor  61 , calculates a manipulated variable MV 1  from a deviation from the first target temperature SV 1 , and controls the first temperature control device  3  on the basis of the manipulated variable MV 1 . 
     The second controller  8  feedback-controls the second temperature control device  4  on the basis of the detection value of the second temperature sensor  62 C so that the temperature of the fluid F flowing out of the second temperature control device  4  becomes the second target temperature SV 2 . That is, the second controller  8  feeds back the temperature T 2   c  which is the detection value of the second temperature sensor  62 C, calculates a manipulated variable MV 2  from a deviation from the second target temperature SV 2 , and controls the second temperature control device  4  on the basis of the manipulated variable MV 2 . 
     The temperature of the fluid F controlled by the first controller  7  is a so-called outlet temperature of the first temperature control device  3 . Note that the temperature of the fluid F controlled by the first controller  7  may be regarded as a so-called inlet temperature of the second temperature control device  4 . 
     The temperature of the fluid F controlled by the second controller  8  is a so-called outlet temperature of the temperature control target S. Note that the temperature of the fluid F controlled by the second controller  8  may be regarded as a so-called inlet temperature of the first temperature control device  3 . Note that in a case where the fluid F at the second predetermined position P 2  is brought to the second target temperature SV 2 , the temperature of the fluid F controlled by the second controller  8  is the temperature of the temperature control target S. 
     The first target temperature SV 1  is determined on the basis on the second target temperature SV 2 . In the present embodiment, the first target temperature SV 1  is determined on the basis of the second target temperature SV 2 , the specified value α related to the temperature control capability of the second temperature control device  4 , and the detection value of the second temperature sensor  62 C. The specified value α is similar to the specified value α described in the above embodiment. In the present embodiment, [SV 1 =SV 2 −α+(SV 2 −T 2   c )]. 
     As described above, according to the present embodiment, the first target temperature SV 1  is determined on the basis of the second target temperature SV 2 , the specified value α related to the temperature control capability of the second temperature control device  4 , and the temperature T 2   c  that is the detection value of the second temperature sensor  62 C. The temperature T 2   c  of the fluid F flowing out of the temperature control target S may fluctuate due to, for example, thermal disturbance. According to the present embodiment, the first target temperature SV 1  is determined in consideration of the fluctuation of the temperature T 2   c . As a result, for example, even if the target temperature of the temperature control target S is changed during the process, the temperature control system  1  can control the temperature of the fluid F with high accuracy using the first temperature control device  3  and the second temperature control device  4 . 
     Third Embodiment 
     A third embodiment will be described. In the following description, the same or equivalent components as those of the above embodiment are denoted by the same symbols, and description thereof is simplified or omitted. 
       FIG.  7    is a block diagram illustrating a temperature control system  1  according to the present embodiment. Also in the present embodiment, a control method for bringing the temperature of the fluid F at the third predetermined position P 3  set between the outlet Mb of the temperature control target S and the inlet Mc of the first temperature control device  3  to the second target temperature SV 2  will be described. Note that a control method for bringing the temperature of the temperature control target S at the second predetermined position P 2  to the second target temperature SV 2  is similar. 
     As illustrated in  FIG.  7   , the temperature control system  1  includes the circulation flow path  2  including the temperature control target S, the first temperature control device  3 , the second temperature control device  4 , the first temperature sensor  61 , the second temperature sensor  62 C, the first controller  7 , and a second controller  8 . 
     In the present embodiment, the second controller  8  includes: a feedback control unit  81  that outputs a control command to the second temperature control device  4  on the basis of a detection value of the second temperature sensor  62 C; and a feedforward control unit  82  that outputs a control command to the second temperature control device  4  on the basis of a thermal disturbance drive signal d input to the temperature control target S, a dynamic characteristic model of the temperature control target S, and a dynamic characteristic model of the second temperature control device  4 . 
     The feedback control unit  81  feedback-controls the second temperature control device  4  on the basis of a detection value of the second temperature sensor  62 C so that the temperature of the fluid F flowing out of the second temperature control device  4  becomes the second target temperature SV 2 . That is, the feedback control unit  81  feeds back the temperature T 2   c , which is the detection value of the second temperature sensor  62 C, and calculates a manipulated variable MV 2   a  from the deviation from the second target temperature SV 2 . 
     The feedforward control unit  82  feedforward-controls the second temperature control device  4  so that the temperature of the fluid F flowing out of the temperature control target S becomes the second target temperature SV 2  on the basis of the thermal disturbance drive signal d input to the temperature control target S, the dynamic characteristic model of the temperature control target S, and the dynamic characteristic model of the second temperature control device  4 . 
     The thermal disturbance drive signal d is a signal that generates thermal disturbance received by the temperature control target S. In a case where the temperature control target S is a wafer holder of a plasma processing apparatus, a thermal disturbance drive signal d for generating plasma is input to the plasma processing apparatus. When the thermal disturbance drive signal d is input to the plasma processing apparatus, plasma is generated, and the temperature control target S receives thermal disturbance due to the plasma. The relationship between the thermal disturbance drive signal d and the thermal disturbance received by the temperature control target S is known data derived by an experiment or the like. 
     The dynamic characteristic model of the temperature control target S and the dynamic characteristic model of the second temperature control device  4  are derived by an experiment or simulation and stored in the feedforward control unit  82 . The feedforward control unit  82  can predict the temperature of the fluid F flowing out of the temperature control target S by inputting the thermal disturbance drive signal d to the dynamic characteristic model of the temperature control target S. The feedforward control unit  82  can also calculate a manipulated variable MV 2   b  for bringing the temperature of the fluid F flowing out of the temperature control target S to the second target temperature SV 2  on the basis of the dynamic characteristic model of the second temperature control device  4 . That is, the feedforward control unit  82  can calculate the manipulated variable MV 2   b  for canceling the thermal disturbance received by the temperature control target S on the basis of the thermal disturbance drive signal d input to the temperature control target S, the dynamic characteristic model of the temperature control target S, and the dynamic characteristic model of the second temperature control device  4 . 
     The second controller  8  calculates a manipulated variable MV 2  by adding up the manipulated variable MV 2   a  calculated by the feedback control unit  81  and the manipulated variable MV 2   b  calculated by the feedforward control unit  82  and controls the second temperature control device  4  on the basis of the manipulated variable MV 2 . 
     Note that, in a case where the thermal disturbance drive signal d is zero, the feedforward control unit  82  does not calculate the manipulated variable MV 2   b.    
     The first controller  7  feedback-controls the first temperature control device  3  on the basis of a detection value of the first temperature sensor  61  so that the temperature of the fluid F flowing out of the first temperature control device  3  becomes the first target temperature SV 1 . That is, the first controller  7  feeds back the temperature T 1  which is the detection value of the first temperature sensor  61 , calculates a manipulated variable MV 1  from a deviation from the first target temperature SV 1 , and controls the first temperature control device  3  on the basis of the manipulated variable MV 1 . 
     The first target temperature SV 1  is determined on the basis on the second target temperature SV 2 . As in the second embodiment described above, the first target temperature SV 1  is determined on the basis of the second target temperature SV 2 , a specified value α related to the temperature control capability of the second temperature control device  4 , and the detection value of the second temperature sensor  62 C. Also in the present embodiment, [SV 1 =SV 2 −α+(SV 2 −T 2   c )]. 
     As described above, according to the present embodiment, the second controller  8  includes the feedback control unit  81  and the feedforward control unit  82 . The feedforward control unit  82  can control the second temperature control device  4  in consideration of thermal disturbance received by the temperature control target S. Therefore, the temperature control system  1  can control the temperature of the fluid F with high accuracy using the first temperature control device  3  and the second temperature control device  4 . 
     Fourth Embodiment 
     A fourth embodiment will be described. In the following description, the same or equivalent components as those of the above embodiment are denoted by the same symbols, and description thereof is simplified or omitted. 
       FIG.  8    is a block diagram illustrating a temperature control system  1  according to the present embodiment. Also in the present embodiment, a control method for bringing the temperature of the fluid F at the third predetermined position P 3  set between the outlet Mb of the temperature control target S and the inlet Mc of the first temperature control device  3  to the second target temperature SV 2  will be described. Note that a control method for bringing the temperature of the temperature control target S at the second predetermined position P 2  to the second target temperature SV 2  is similar. 
     As illustrated in  FIG.  8   , the temperature control system  1  includes the circulation flow path  2  including the temperature control target S, the first temperature control device  3 , the second temperature control device  4 , the first temperature sensor  61 , the second temperature sensor  62 C, the first controller  7 , and a second controller  8 . 
     In the present embodiment, the second controller  8  includes: a feedback control unit  81  that outputs a control command to the second temperature control device  4  on the basis of a detection value of the second temperature sensor  62 C; and a preview feedforward control unit  83  that outputs a control command to the second temperature control device  4  on the basis of a thermal disturbance drive future signal df scheduled to be input to the temperature control target S, a dynamic characteristic model of the temperature control target S, and a dynamic characteristic model of the second temperature control device  4 . 
     The feedback control unit  81  feedback-controls the second temperature control device  4  on the basis of a detection value of the second temperature sensor  62 C so that the temperature of the fluid F flowing out of the second temperature control device  4  becomes the second target temperature SV 2 . That is, the feedback control unit  81  feeds back the temperature T 2   c , which is the detection value of the second temperature sensor  62 C, and calculates a manipulated variable MV 2   a  from the deviation from the second target temperature SV 2 . 
     The preview feedforward control unit  83  feedforward-controls the second temperature control device  4  so that the temperature of the fluid F flowing out of the temperature control target S becomes the second target temperature SV 2  on the basis of the thermal disturbance drive future signal df scheduled to be input to the temperature control target S, the dynamic characteristic model of the temperature control target S, and the dynamic characteristic model of the second temperature control device  4 . 
     The thermal disturbance drive future signal df is a signal that is scheduled to generate thermal disturbance to be received by the temperature control target S. In a case where the temperature control target S is a wafer holder of a plasma processing apparatus, a thermal disturbance drive signal d for generating plasma is input to the plasma processing apparatus. When the thermal disturbance drive signal d is input to the plasma processing apparatus, plasma is generated, and the temperature control target S receives thermal disturbance due to the plasma. The relationship between the thermal disturbance drive signal d and the thermal disturbance received by the temperature control target S is known data derived by an experiment or the like. In addition, the thermal disturbance drive signal d has been created as a specification of the process. The thermal disturbance drive future signal df is a thermal disturbance drive signal d scheduled to be input at a future time later than a time at which the signal is actually input to the plasma processing apparatus. That is, in a case where the time at which the thermal disturbance drive signal d is actually input to the plasma processing apparatus is denoted as t 0 , the thermal disturbance drive future signal df is a thermal disturbance drive signal d scheduled to be input at a future time t 1  later than the time t 0  by a certain number of steps. The thermal disturbance drive future signal df is derived from the specifications of the process. 
     The feedforward control unit  82  can calculate a manipulated variable MV 2   c  for canceling the thermal disturbance scheduled to be received by the temperature control target S at the future time t 1  on the basis of the thermal disturbance drive future signal df scheduled to be input to the temperature control target S, the dynamic characteristic model of the temperature control target S, and the dynamic characteristic model of the second temperature control device  4 . 
     The second controller  8  calculates a manipulated variable MV 2  by adding up the manipulated variable MV 2   a  calculated by the feedback control unit  81  and the manipulated variable MV 2   c  calculated by the feedforward control unit  82  and controls the second temperature control device  4  on the basis of the manipulated variable MV 2 . 
     The first controller  7  feedback-controls the first temperature control device  3  on the basis of a detection value of the first temperature sensor  61  so that the temperature of the fluid F flowing out of the first temperature control device  3  becomes the first target temperature SV 1 . That is, the first controller  7  feeds back the temperature T 1  which is the detection value of the first temperature sensor  61 , calculates a manipulated variable MV 1  from a deviation from the first target temperature SV 1 , and controls the first temperature control device  3  on the basis of the manipulated variable MV 1 . 
     The first target temperature SV 1  is determined on the basis on the second target temperature SV 2 . As in the second embodiment described above, the first target temperature SV 1  is determined on the basis of the second target temperature SV 2 , a specified value α related to the temperature control capability of the second temperature control device  4 , and the detection value of the second temperature sensor  62 C. Also in the present embodiment, [SV 1 =SV 2 −α+(SV 2 −T 2   c )]. 
     As described above, according to the present embodiment, the second controller  8  includes the feedback control unit  81  and the preview feedforward control unit  83 . The preview feedforward control unit  83  can control the second temperature control device  4  in consideration of the thermal disturbance scheduled to be received by the temperature control target S. Therefore, the temperature control system  1  can control the temperature of the fluid F with high accuracy using the first temperature control device  3  and the second temperature control device  4 . 
     Note that, in the first to fourth embodiments described above, it is based on the premise that the specified value α is a variable that varies on the basis of the second target temperature SV 2 . The specified value α may be a constant. 
     Fifth Embodiment 
     A fifth embodiment will be described. In the following description, the same or equivalent components as those of the above embodiment are denoted by the same symbols, and description thereof is simplified or omitted. 
       FIG.  9    is a block diagram illustrating a temperature control system  1  according to the present embodiment. Also in the present embodiment, a control method for bringing the temperature of the fluid F at the third predetermined position P 3  set between the outlet of the temperature control target S and the inlet of the first temperature control device  3  to the second target temperature SV 2  will be described. Note that a control method for bringing the temperature of the temperature control target S at the second predetermined position P 2  to the second target temperature SV 2  is similar. 
     As illustrated in  FIG.  9   , the temperature control system  1  includes the circulation flow path  2  including the temperature control target S, the first temperature control device  3 , the second temperature control device  4 , the first temperature sensor  61 , the second temperature sensor  62 C, the first controller  7 , and a second controller  8 . 
     As in the third embodiment described above, the second controller  8  includes: a feedback control unit  81  that outputs a control command to the second temperature control device  4  on the basis of a detection value of the second temperature sensor  62 C; and a feedforward control unit  82  that outputs a control command to the second temperature control device  4  on the basis of a thermal disturbance drive signal d input to the temperature control target S, a dynamic characteristic model of the temperature control target S, and a dynamic characteristic model of the second temperature control device  4 . The second controller  8  also includes a low-pass filter  84 . 
     The feedback control unit  81  feedback-controls the second temperature control device  4  on the basis of a detection value of the second temperature sensor  62 C so that the temperature of the fluid F flowing out of the second temperature control device  4  becomes the second target temperature SV 2 . That is, the feedback control unit  81  feeds back the temperature T 2   c , which is the detection value of the second temperature sensor  62 C, and calculates a manipulated variable MV 2   a  from the deviation from the second target temperature SV 2 . 
     The feedforward control unit  82  feedforward-controls the second temperature control device  4  so that the temperature of the fluid F flowing out of the temperature control target S becomes the second target temperature SV 2  on the basis of the thermal disturbance drive signal d input to the temperature control target S, the dynamic characteristic model of the temperature control target S, and the dynamic characteristic model of the second temperature control device  4 . 
     The second controller  8  calculates a manipulated variable MV 2  by adding up the manipulated variable MV 2   a  calculated by the feedback control unit  81  and the manipulated variable MV 2   b  calculated by the feedforward control unit  82  and controls the second temperature control device  4  on the basis of the manipulated variable MV 2 . 
     The first controller  7  feedback-controls the first temperature control device  3  on the basis of a detection value of the first temperature sensor  61  so that the temperature of the fluid F flowing out of the first temperature control device  3  becomes the first target temperature SV 1 . That is, the first controller  7  feeds back the temperature T 1  which is the detection value of the first temperature sensor  61 , calculates a manipulated variable MV 1  from a deviation from the first target temperature SV 1 , and controls the first temperature control device  3  on the basis of the manipulated variable MV 1 . 
     The low-pass filter  84  generates a signal dc obtained by cutting off high-frequency components of the thermal disturbance drive signal d used for determination of the first target temperature SV 1 . Even when the thermal disturbance drive signal d rapidly changes, the low-pass filter  84  suppresses a rapid change in the first target temperature SV 1 . 
     The first target temperature SV 1  is determined on the basis on the second target temperature SV 2 . In the present embodiment, the first target temperature SV 1  is determined on the basis of the second target temperature SV 2  and the thermal disturbance drive signal d. In the present embodiment, [SV 1 =SV 2 −dc×β]. Note that β is a conversion coefficient. 
     As described above, according to the present embodiment, the first target temperature SV 1  is determined on the basis of the second target temperature SV 2  and the thermal disturbance drive signal d. Depending on the magnitude of the thermal disturbance, the temperature control capability of the second temperature control device  4  may be insufficient. The thermal disturbance drive signal d is used for determination of the first target temperature SV 1  in order to compensate for the shortage of the temperature control capability of the second temperature control device  4  by the first temperature control device  3 . In a case where the thermal disturbance drive signal d increases, the first target temperature SV 1  decreases. As a result, the first temperature control device  3  can compensate for the shortage of the temperature control capability of the second temperature control device  4 . 
     Note that the second controller  8  may include the preview feedforward control unit  83  as described in the fourth embodiment. 
     OTHER EMBODIMENTS 
     In the above-described embodiments, it is based on the premise that the first portion  2 A to which the first temperature control device  3  supplies the fluid F is the tank  9  disposed in the circulation flow path  2 . The first portion  2 A to which the first temperature control device  3  supplies the fluid F may be a part of the circulation flow path  2 . 
     REFERENCE SIGNS LIST 
     
         
         
           
               1  TEMPERATURE CONTROL SYSTEM 
               2  CIRCULATION FLOW PATH 
               2 A FIRST PORTION 
               2 B SECOND PORTION 
               3  FIRST TEMPERATURE CONTROL DEVICE 
               4  SECOND TEMPERATURE CONTROL DEVICE 
               5  PUMP 
               6  TEMPERATURE SENSOR 
               7  FIRST CONTROLLER 
               8  SECOND CONTROLLER 
               9  TANK 
               10 L LOW-TEMPERATURE CONTROL UNIT 
               10 H HIGH-TEMPERATURE CONTROL UNIT 
               11 L LOW-TEMPERATURE FLOW PATH 
               11 H HIGH-TEMPERATURE FLOW PATH 
               12 L LOW-TEMPERATURE OVERFLOW CHANNEL 
               12 H HIGH-TEMPERATURE OVERFLOW CHANNEL 
               13  VALVE SYSTEM 
               14 L LOW-TEMPERATURE FLOW RATE ADJUSTING VALVE 
               14 H HIGH-TEMPERATURE FLOW RATE ADJUSTING VALVE 
               15 L LOW-TEMPERATURE ON-OFF VALVE 
               15 H HIGH-TEMPERATURE ON-OFF VALVE 
               40  BODY MEMBER 
               42  TEMPERATURE CONTROL FLOW PATH 
               44  HEAT EXCHANGE PLATE 
               45  DRIVE CIRCUIT 
               50  TEMPERATURE CONTROL UNIT 
               51  CASE 
               60  THERMOELECTRIC MODULE 
               61  FIRST TEMPERATURE SENSOR 
               62  SECOND TEMPERATURE SENSOR 
               62 A SECOND TEMPERATURE SENSOR 
               62 B SECOND TEMPERATURE SENSOR 
               62 C SECOND TEMPERATURE SENSOR 
               63  THERMOELECTRIC SEMICONDUCTOR ELEMENT 
               63 P p-TYPE THERMOELECTRIC SEMICONDUCTOR ELEMENT 
               63 N n-TYPE THERMOELECTRIC SEMICONDUCTOR ELEMENT 
               65  FIRST ELECTRODE 
               66  SECOND ELECTRODE 
               81  FEEDBACK CONTROL UNIT 
               82  FEEDFORWARD CONTROL UNIT 
               83  PREVIEW FEEDFORWARD CONTROL UNIT 
               84  LOW-PASS FILTER 
             d THERMAL DISTURBANCE DRIVE SIGNAL 
             df THERMAL DISTURBANCE DRIVE FUTURE SIGNAL 
             F FLUID 
             Ma INLET 
             Mb OUTLET 
             Mc INLET 
             Md OUTLET 
             Me INLET 
             Mf OUTLET 
             MV 1  MANIPULATED VARIABLE 
             MV 2  MANIPULATED VARIABLE 
             P 1  FIRST PREDETERMINED POSITION 
             P 2  SECOND PREDETERMINED POSITION 
             P 3  THIRD PREDETERMINED POSITION 
             SV 1  FIRST TARGET TEMPERATURE 
             SV 2  SECOND TARGET TEMPERATURE 
             S TEMPERATURE CONTROL TARGET 
             T 1  TEMPERATURE 
             T 2   a  TEMPERATURE 
             T 2   b  TEMPERATURE 
             T 2   c  TEMPERATURE