JP6429084B2 - Temperature control device, temperature control method and prober for wafer mounting table - Google Patents

Description

  The present invention relates to a temperature control device, a temperature control method, and a prober for a wafer mounting table, and more particularly to a technique for controlling the temperature of a wafer mounting table to a temperature lower than room temperature.

  In the semiconductor manufacturing process, various processes are performed on a thin disk-shaped semiconductor wafer to form a plurality of chips (dies) each having a semiconductor device (device). Each chip is inspected for electrical characteristics and then separated by a dicer or the like, and then fixed to a lead frame or the like and assembled.

  The inspection of the electrical characteristics is performed by a wafer test system composed of a prober and a tester. The prober fixes the semiconductor wafer to the wafer mounting table and brings the probe into contact with the electrode pad of each chip. The tester supplies power and various test signals from the terminals connected to the probe, and analyzes the signals output to the electrodes of the chip with the tester to check whether it operates normally.

  However, semiconductor devices are used in a wide range of applications. Some semiconductor devices are used in low-temperature environments such as -60 ° C and high-temperature environments such as 200 ° C. It is required that inspection can be performed.

  Therefore, a wafer temperature adjustment that changes the temperature of the mounting surface of the wafer mounting table such as a heating mechanism (heater) or a cooling mechanism (chiller mechanism) below the mounting surface of the wafer mounting table that holds the semiconductor wafer in the prober. An apparatus is provided to heat or cool the wafer held on the wafer mounting table.

  In general, the cooling mechanism for cooling the wafer mounting table includes a line for circulating the coolant on the wafer mounting table, and a heat pump type refrigerator that circulates the refrigerant. And a line for cooling the coolant by exchanging heat, and the refrigerator is controlled so that the temperature of the coolant supplied to the wafer mounting table becomes the target cooling temperature.

  However, the heat pump type refrigerator is excellent in energy saving, but the condensation state of the condenser is easy to change and the refrigerant temperature is likely to fluctuate. There is a problem that it takes time and response performance (response) is slow.

  When the semiconductor device is inspected by a prober at a high temperature or a low temperature, only the portion of the wafer mounting table is held at a high temperature or a low temperature, so that the temperature of the wafer mounting table changes due to a temperature difference from the surroundings. Further, as described above, the temperature of the wafer mounting table changes due to the heat generation of the chip accompanying the inspection. Therefore, although the cooling mechanism and the heating mechanism are controlled based on the measured temperature of the coolant flowing through the wafer mounting table, their response performance (response) becomes a problem for accurate temperature control.

  For example, even if the cooling mechanism or the heating mechanism is controlled so that the measured temperature deviates from the target cooling temperature and the temperature deviation is corrected immediately, if the response is slow, it takes a long time to be corrected. In addition, a problem arises in that the temperature deviation becomes large during that time, and the target cooling temperature cannot be accurately controlled.

  On the other hand, the heater that generates heat immediately when the current is increased has a relatively fast response performance.

Therefore, Patent Document 1 proposes to provide an in-line heater in a line for cooling the mounting table as a cooling mechanism for the wafer mounting table. That is, the temperature of the coolant flowing in the wafer mounting table is adjusted to be lower than the target cooling temperature by heat exchange with the refrigerant of the refrigerator, and the low temperature coolant is adjusted to the target cooling temperature with an in-line heater. The response performance is increased by heating.

JP 2008-311492 A

  However, the in-line heater consumes a large amount of power and has a problem in terms of energy saving. In particular, the use of an in-line heater with large power consumption in a cooling mechanism using a heat pump type refrigerator excellent in energy saving is not suitable for the purpose of energy saving.

  The present invention has been made in view of such circumstances, and is capable of speeding up the response performance with high accuracy without using an in-line heater. An object is to provide an apparatus, a temperature control method, and a prober.

In order to achieve the above object, the present invention provides a temperature control device for a wafer mounting table including a cooling mechanism for cooling a wafer mounting table on which a semiconductor wafer is mounted to a target cooling temperature, wherein the cooling mechanism includes the wafer mounting table. And a heat pump type refrigerator that circulates the refrigerant, and heat-exchanges the refrigerant and the cooling liquid of the mounting base cooling line to cool the target liquid to the target cooling. A refrigerator line that cools to a temperature lower than the temperature, and a heating liquid that heats the coolant divided from the outlet side of the wafer mounting table by condensation heat generated when the refrigerant is liquefied by the condenser of the refrigerator line A heating line for joining the wafer mounting table to the inlet side, a cooling liquid for circulating the mounting table cooling line, and a heating liquid for joining the heating line to the inlet side of the wafer mounting table A mixing ratio adjusting means for adjusting the mixing ratio of the coolant temperature detecting means for detecting a coolant temperature of the wafer mounting base inlet side, the target cooling temperature based on a measurement result of the coolant temperature detecting means And a coolant temperature adjusting means for controlling the mixing ratio adjusting means.

  According to the temperature control device for a wafer mounting table of the present invention, a target liquid is mixed by mixing a liquid adjusted to a temperature lower than a target cooling temperature with a heating liquid heated by the condensation heat of a refrigerator line that has been conventionally exhausted. Since the temperature is controlled, it is possible to reduce the power consumption of the in-line heater used compared to the conventional case.

  In addition, the control responsiveness of controlling to the target cooling temperature by directly mixing the cooling liquid and the heating liquid by the mixing ratio adjusting means is good.

  As a result, since the response performance can be increased with high accuracy without using an in-line heater, a temperature control device for a wafer mounting table that is more energy-saving than the conventional one can be provided.

  As an aspect of the temperature control device for the wafer mounting table of the present invention, the cooling liquid of the mounting table cooling line and the heating liquid of the heating line are supplied by a single liquid supply pump, and the cooling of the mounting table cooling line is performed. It is preferable that a constant pressure valve is provided upstream of the junction where the heating liquid of the heating line joins the liquid, and the discharge pressure of the liquid feeding pump is made larger than the set pressure of the constant pressure valve.

  Thereby, the pressure fluctuations of the cooling liquid flowing through the mounting table cooling line and the heating liquid flowing through the heating line are reduced and the flow is stabilized, so that the mixing ratio of the cooling liquid and the heating liquid can be controlled with high accuracy.

  As an aspect of the temperature control device for a wafer mounting table of the present invention, the refrigerator line is a two-way refrigeration circuit in which two refrigerators of a low temperature side circuit and a high temperature side circuit are combined via a heat exchanger. preferable.

  Thereby, since the temperature variation of the refrigerant | coolant in a refrigerator line can be made small, the coolant temperature of a mounting base cooling line can be controlled with high precision. Therefore, the mixing ratio of the cooling liquid and the heating liquid can be controlled with higher accuracy.

In order to achieve the above object, according to the present invention, there is provided a temperature control method for a wafer mounting table for cooling a wafer mounting table on which a semiconductor wafer is mounted to a target cooling temperature. A low-temperature cooling liquid forming step of forming a low-temperature cooling liquid having a temperature lower than the target cooling temperature by exchanging heat with a refrigerant cooled by a heat pump type refrigerator, and a condenser of the refrigerator A heating liquid forming step of heating the cooling liquid divided from the outlet side of the wafer mounting table by condensation heat generated when the refrigerant is liquefied to form a heating liquid having a temperature higher than the target cooling temperature; and the wafer. a coolant temperature detection step of detecting a coolant temperature of the mounting base of the inlet side, the coolant temperature of the coolant temperature detected inlet side measurement based on the result of the wafer mounting base process it to the target cooling temperature A mixing step of mixing the low temperature coolant and the heating liquid so as to comprising the.

  As a result, it is possible to increase the accuracy and speed of response performance without using an in-line heater, and thus it is possible to provide a temperature control method for a wafer mounting table that is more energy-saving than conventional ones.

To achieve the above object, the present invention is to inspect multiple semiconductor devices formed on a semiconductor wafer mounted on the wafer mounting base with a tester, the terminals of the tester of the semiconductor device electrode In the prober device connected to the wafer mounting table, the wafer mounting table includes the temperature control device described above.

  As a result, it is possible to increase the accuracy and speed of response without using an in-line heater, and thus it is possible to provide a prober that is more energy-saving than conventional ones.

  According to the temperature control device, temperature control method, and prober of the wafer mounting table of the present invention, it is possible to increase the accuracy and speed of response without using an in-line heater. A temperature control device, a temperature control method, and a prober can be provided.

Schematic configuration diagram of a prober equipped with a temperature control device composed of a heating mechanism for heating the wafer mounting table and a cooling mechanism for cooling it. Overall configuration of cooling mechanism Control flow diagram for PID control of valve opening of proportional two-way valve in wafer mounting table cooling control method

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments relating to a temperature control device, a temperature control method, and a prober for a wafer mounting table according to the present invention will be described below with reference to the accompanying drawings.

[Prober]
FIG. 1 is a schematic configuration diagram of a prober including a temperature control device including a heater that constitutes a heating mechanism that heats the wafer mounting table and a cooling mechanism that cools the wafer mounting table.

  As shown in FIG. 1, the prober 10 mainly includes a plurality of wafer mounting tables 12 (also referred to as “wafer chucks”) that hold a semiconductor wafer W and semiconductor devices (devices) formed on the semiconductor wafer W. The probe card 16 having the probe 14 made according to the electrode arrangement of the chip and the temperature controller 18 are configured. The temperature control device 18 includes a heater 20 that constitutes a heating mechanism, and a cooling mechanism 22 that will be described in detail later.

  In the wafer mounting table 12, a heater 20 and a mounting table cooling line 24 that is a component of the cooling mechanism 22 are provided. The heater 20 generates heat to heat the surface of the wafer mounting table 12 that holds the semiconductor wafer W. Further, the coolant flows through the mounting table cooling line 24 to cool the surface of the wafer mounting table 12 that holds the semiconductor wafer W.

  Although FIG. 1 shows an example in which the heater 20 is provided on the side close to the surface of the wafer mounting table 12 and the mounting table cooling line 24 is provided below, the heater 20 is provided below the mounting table cooling line 24. May be.

  In addition, a vacuum path (not shown) for vacuum-sucking the semiconductor wafer W is provided in the wafer mounting table 12, and the mounting table cooling line 24, the heater 20 and the vacuum path in the wafer mounting table 12 are provided. There are various variations of the arrangement.

  When the semiconductor wafer W is inspected at a predetermined temperature, the control device 26 detects the temperature of the wafer mounting table 12 while the semiconductor wafer W is held on the wafer mounting table 12. Based on the temperature, the heater 20 and the cooling mechanism 22 of the wafer mounting table 12 are controlled so that the wafer mounting table 12 has a predetermined temperature. The wafer mounting table 12 is made of a metal such as aluminum or copper, or a material such as ceramic having good thermal conductivity.

  The tester mainly includes a tester body 30 and a connection portion 32 that electrically connects the terminals of the tester body 30 and the terminals of the probe card 16. The connection part 32 has a connection terminal mechanism using a spring, a so-called spring pin structure. The prober 10 performs measurement in cooperation with the tester in the inspection of the semiconductor wafer W, but the power supply system and the mechanism part are devices independent of the tester body and the test head.

  In addition to the above-described configuration, the prober 10 has an XY moving unit that moves the wafer mounting table 12 in the X direction and the Y direction on the horizontal plane, a Z moving unit that moves in the Z direction on the vertical plane, and a rotation. A rotational movement unit that moves the direction, an alignment camera that detects the arrangement direction of the chips formed on the semiconductor wafer, a needle position detection camera that detects the position of the probe, and the like are provided. However, such components of the prober 10 are well known as described in Japanese Patent Application Laid-Open No. 2007-324189 and are not directly related to the present invention, and therefore are not shown here.

[Cooling mechanism]
Next, the configuration of the cooling mechanism 22 will be described with reference to FIG.

  As shown in FIG. 2, the cooling mechanism 22 is mainly composed of the mounting table cooling line 24, the refrigerator line 34, the heating line 36, the mixing ratio adjusting means 38, and the coolant temperature adjusting means 40. Is done. The coolant temperature adjusting means 40 may also be used in the control device 26 in FIG. 1 that controls the temperature of the wafer mounting table 12.

  The mounting table cooling line 24 is a line for circulating the coolant in the wafer mounting table 12, and forms a circulation line indicated by arrows A → B → C → D in FIG. The mounting table cooling line 24 is provided with a liquid feed pump 42, a cooling coil 44, and a coolant temperature detecting means 46 in order from the outlet side of the wafer mounting table 12. The coolant temperature detecting means 46 detects the inlet temperature of the wafer mounting table 12. As the cooling liquid, for example, water or fluorine-based liquid (for example, Novec (registered trademark) series of 3M (trademark registered) Japan Co., Ltd., or Galden (trademark registered) series of Solvay Specialty Polymers Japan Co., Ltd.) is used. It can be used suitably.

  The refrigerator line 34 has a heat pump type refrigerator in which the refrigerant circulates, and the coolant is lower than the target cooling temperature of the wafer mounting table 12 by exchanging heat between the refrigerant and the cooling liquid in the mounting table cooling line 24. A line that cools to a temperature. In FIG. 2, the portion of the refrigerator line 34 in the cooling mechanism 22 is surrounded by a two-dot chain line.

  In the present embodiment, the refrigerator line 34 is described as a dual refrigeration circuit in which two refrigerators of a high temperature side circuit 50 and a low temperature side circuit 52 are combined via a first heat exchanger 48. However, the present invention can also be applied to a one-way refrigeration circuit.

  The high temperature side circuit 50 forms a circulation line indicated by arrows E → F → G → H in FIG. 2, and the first compressor (compressor) 54, the first condenser 56, and the first that constitute the heat pump are formed in the circulation line. An expansion valve 58 and a first evaporator 60 are provided. A refrigerant (for example, alternative chlorofluorocarbon) is circulated through the circulation line. The first condenser 56 includes a condensing coil 56 </ b> A and a cooling fan 72, and the refrigerant flowing through the condensing coil 56 </ b> A is cooled by the cooling fan 72.

  Thereby, in the high temperature side circuit 50, the liquid refrigerant liquefied by the first condenser 56 flows to the first evaporator 60 through the first expansion valve 58, and is vaporized by the first evaporator 60 to become a gaseous refrigerant. A circulation flow is formed which is compressed by the first compressor 54 and then returns to the first condenser 56 again. When the gaseous refrigerant condenses in the first condenser 56 and becomes a liquid refrigerant, the heat of condensation (heat) is dissipated, and when the liquid refrigerant is vaporized and becomes a gaseous refrigerant in the first evaporator 60. Releases heat of vaporization (cold heat).

  The low temperature side circuit 52 forms a circulation line indicated by arrows I → J → K → L in FIG. 2, and a second compressor (compressor) 62, a second condenser 64, and a second compressor constituting a heat pump are formed in the circulation line. An expansion valve 66 and a second evaporator 68 are provided. A refrigerant (for example, alternative chlorofluorocarbon) is circulated through the circulation line.

  Thereby, in the low temperature side circuit 52, the liquid refrigerant liquefied by the second condenser 64 flows to the second evaporator 68 through the second expansion valve 66, and is vaporized by the second evaporator 68 to become a gaseous refrigerant. A circulation line is formed which is compressed by the two compressors 62 and then returns to the second condenser 64 again.

  Similarly to the high temperature side circuit 50, the low temperature side circuit 52 radiates condensation heat (warm heat) when the gaseous refrigerant condenses into a liquid refrigerant in the second condenser 64, and the second evaporator 68 When the liquid refrigerant is vaporized to become a gaseous refrigerant, heat of vaporization (cold heat) is released.

  And the 1st evaporator 60 of the high temperature side circuit 50 and the 2nd condenser 64 of the low temperature side circuit 52 comprise the 1st heat exchanger 48 mentioned above. That is, the heat of vaporization generated in the first evaporator 60 of the high temperature side circuit 50 is used as cold heat for cooling the second condenser 64 of the low temperature side circuit 52.

  The second evaporator 68 of the low temperature side circuit 52 and the cooling coil 44 of the mounting table cooling line 24 constitute a second heat exchanger 70. That is, the coolant flowing through the cooling coil 44 is cooled by the heat of vaporization generated by the second evaporator 68 of the low temperature side circuit 52.

  In FIG. 2, the first condenser 56 of the high-temperature circuit 50 is shown as an air-cooled type in which the refrigerant flowing through the first condensing coil 56 </ b> A is cooled by the cooling fan 72, but a water-cooled type can also be adopted. Also. Capillary (capillary) tubes may be employed as the first expansion valve 58 and the second expansion valve 66.

  In this way, by configuring the refrigerator line 34 with a binary refrigeration circuit, temperature fluctuations can be reduced as compared with a single refrigeration circuit.

  The heating line 36 converts a part of the coolant on the outlet side of the wafer mounting table 12 by the condensation heat (warm heat) generated when the refrigerant is liquefied by the first condenser 56 of the high temperature side circuit 50 in the refrigerator line 34. This is a line that heats and returns to the entrance side of the wafer mounting table 12, and forms a line indicated by arrows M → N → P in FIG.

  The refrigerant flowing in the refrigerator line 34 and the coolant flowing in the heating line 36 exchange heat on the primary side (upstream side in the refrigerant flow direction) of the first condenser 56 in the high-temperature side circuit 50 of the refrigerator line 34. A third heat exchanger 74 is provided. The third heat exchanger 74 includes a heat exchange coil 74 </ b> A provided on the primary side of the first condenser 56 and a heating coil 74 </ b> B provided on the heating line 36.

  That is, in the heating line 36, a part of the coolant on the outlet side of the wafer mounting table 12 is diverted from the branch point R between the liquid feed pump 42 and the cooling coil 44 of the mounting table cooling line 24, and the third heat exchange is performed. The forward path 78 to the heating coil 74B of the vessel 74 and the cooling liquid of the mounting table cooling line 24 join at the junction S between the heating coil 74B and the cooling coil 44 of the mounting table cooling line 24 and the coolant temperature detecting means 46. And a return path 80.

  The gaseous refrigerant warmed in the first evaporator 60 of the high-temperature circuit 50 by the third heat exchanger 74 configured as described above is exhausted by the cooling fan 72 of the first condenser 56 (condensation heat (hot heat)) ( Heat is exchanged with the coolant before the temperature drops due to exhaust heat, and the coolant is heated. Thereby, in the 3rd heat exchanger 74, transfer of much warmth is attained and the cooling fluid which flows through the heating line 36 can be heated effectively.

  As can be seen from the flow path between the mounting table cooling line 24 and the heating line 36, the heating line 36 contains the same liquid as the coolant flowing through the mounting table cooling line 24 (for example, water or the above-described fluorinated liquid). Flowing. However, for convenience of explanation, the liquid flowing through the mounting table cooling line 24 is referred to as a cooling liquid, and the liquid flowing through the heating line 36 is referred to as a heating liquid.

  A mixing ratio adjusting means 38 is provided immediately before the junction S of the return line 80.

  The mixing ratio adjusting means 38 is for adjusting the mixing ratio between the circulating amount of the cooling liquid circulating through the mounting table cooling line 24 and the returning amount of the heating liquid returned from the heating line 36 to the inlet side of the wafer mounting table 12. It is. As the mixing ratio adjusting means 38, for example, a proportional two-way valve 38A, which is an electric valve and whose flow rate changes linearly with respect to the valve opening, can be suitably used. To do.

  The coolant temperature adjusting means 40 controls the refrigerator line 34 based on the measurement result of the coolant temperature detecting means 46 so that the temperature of the wafer mounting table 12 becomes the target cooling temperature, and the valve of the proportional two-way valve 38A. The opening is PID controlled (Proportional Integral Derivative Controller).

  That is, the coolant temperature adjusting means 40 and the refrigerator line 34 are connected by a signal cable (or wireless). The coolant temperature adjusting means 40 and the coolant temperature detecting means 46 are connected by a signal cable (or wireless), and the coolant temperature detecting means 46 and the proportional two-way valve 38A are connected by a signal cable (or wireless). Connected.

  In addition, as can be seen from FIG. 2, the power for circulating the cooling liquid in the mounting table cooling line 24 and the power for feeding the heating liquid in the heating line 36 are the same as the power supply for one unit arranged in the mounting table cooling line 24. This is done with the liquid pump 42. As a result, the length of the pipe through which the liquid is fed by the liquid feed pump 42 is increased by the amount corresponding to the heating line 36, so that the pressure loss is greater than in the case of only the mounting table cooling line 24.

  Therefore, the constant pressure valve 82 is provided upstream of the junction S where the heating liquid of the heating line 36 merges with the cooling liquid of the mounting table cooling line 24, and the discharge pressure of the liquid feed pump 42 is larger than the set pressure of the constant pressure valve 82. It is preferable to do. Thereby, since the flow of the cooling liquid flowing through the mounting table cooling line 24 and the flow of the heating liquid flowing through the heating line 36 are stabilized, the heating liquid and the cooling liquid can be mixed with high accuracy.

  Further, a reserve tank 86 for storing the coolant via the coolant replenishment line 84 is provided at a position higher than the mount table cooling line 24, and the coolant in the reserve tank 86 is transferred to the mount table cooling line 24 by potential energy. Fall naturally. Thereby, even if there is a volume change of the liquid due to expansion or contraction of the cooling liquid flowing through the mounting table cooling line 24 and the heating liquid flowing through the heating line, the pressure in the pipe can be kept constant. Furthermore, even if the piping volume changes due to the expansion or contraction of the piping of the mounting table cooling line 24 and the piping of the heating line 36, the pressure in the piping can be kept constant.

  Therefore, the flow of the cooling liquid flowing through the mounting table cooling line 24 and the flow of the heating liquid flowing through the heating line 36 are stabilized, so that the heating liquid and the cooling liquid can be mixed with high accuracy.

[Cooling control method for wafer mounting table]
Next, a cooling control method for cooling the wafer mounting table 12 to the target cooling temperature T1 using the cooling mechanism 22 configured as described above will be described. In the present embodiment, the target cooling temperature T1 is set to −47 ° C., and the temperature T2 of the cooling liquid without mixing the heating liquid is described as being −52 ° C., which is 5 ° C. lower than the target cooling temperature T1. . The mixing ratio adjusting means 38 will be described using an example of a proportional two-way valve 38A.

  The coolant temperature adjusting means 40 controls the refrigerant temperature of the refrigerator line 34.

  Then, the second heat exchanger 70 exchanges heat between the coolant flowing through the mounting table cooling line 24 and the refrigerant flowing through the refrigerator line 34 so that the coolant is a low-temperature coolant having a temperature lower than the target cooling temperature T1 ( −52 ° C.) (low temperature cooling liquid forming step).

  Further, a part of the cooling liquid on the outlet side of the wafer mounting table 12, that is, the cooling liquid branched from the mounting table cooling line 24 at the branch point R and flowing through the heating line 36 by the third heat exchanger 74 is supplied to the refrigerator line. The first condenser 56 is heated by condensation heat generated when the refrigerant is liquefied. Thereby, a heating liquid having a temperature higher than the target cooling temperature T1 is formed and returned to the entrance of the wafer mounting table 12, that is, the junction S where the mounting table cooling line 24 and the heating line 36 merge (heating liquid forming step). .

  Next, the coolant temperature adjusting means 40 performs PID control on the valve opening degree of the proportional two-way valve 38A, so that the coolant of the mounting table cooling line 24 and the heating fluid that merges from the heating line 36 to the junction S are supplied. By adjusting the mixing ratio, the coolant temperature at the entrance of the wafer mounting table is set to the target cooling temperature T1.

  FIG. 3 is a control flow diagram for PID control of the valve opening of the proportional two-way valve 38A.

  The coolant temperature adjusting means 40 sets the opening degree of the proportional two-way valve 38A that mixes the coolant flowing through the mounting table cooling line 24 with the heating fluid flowing through the refrigerator line 34, for example, 50%. The opening degree of the proportional two-way valve 38A at the start of control is not particularly important, and any opening degree may be set.

  In step 1, the coolant temperature adjusting means 40 compares the measured temperature T2 input from the coolant temperature detecting means 46 with the target coolant temperature T1 input in advance, and determines whether T2> T1. In the case of YES, the measured temperature T2 is higher than the target cooling temperature T1, and it is necessary to reduce the mixing ratio of the heating liquid to be mixed with the cooling liquid. In the case of NO, since it is necessary to increase the mixing ratio of the heating liquid, the process proceeds to Step 3.

  In step 2, the coolant temperature adjusting means 40 controls the opening degree of the proportional two-way valve 38 </ b> A to be small so as to reduce the mixing ratio of the heating liquid to be mixed with the coolant, and proceeds to step 4.

  In step 4, the coolant temperature adjusting means 40 compares the measured temperature T2 with the target cooling temperature T1, and determines whether T2 = T1. In the case of YES, it means that the temperature of the coolant at the inlet of the wafer mounting table 12 has reached the target cooling temperature T1, so that the valve opening degree of the proportional two-way valve 38A is maintained as it is and the processing is ended. If NO, the process proceeds to step 5.

  In step 5, the coolant temperature adjusting means 40 compares the measured temperature T2 with the target cooling temperature T1, and determines whether T2> T1. In the case of YES, it means that the mixing ratio of the heating liquid to be mixed with the cooling liquid is still too large, so the process returns to step 2 and the opening degree of the proportional two-way valve 38A is controlled to be further reduced. In the case of NO, it means that the mixing ratio of the heating liquid to be mixed with the cooling liquid has increased too much, so the control returns to Step 1 and repeats Steps 1 to 5 until T2 = T1.

  On the other hand, in step 3, the coolant temperature adjusting means 40 determines whether T2 <T1. In the case of YES, the measured temperature T2 is lower than the target cooling temperature T1, and it is necessary to increase the mixing ratio of the heating liquid. In the case of NO, since it is necessary to reduce the mixing ratio of the heating liquid, the process returns to the control start in step 1.

  In step 6, the coolant temperature adjusting means 40 controls the opening degree of the proportional two-way valve 38A to be increased so as to increase the mixing ratio of the heating liquid to be mixed with the coolant, and the process proceeds to step 7.

  In step 7, the coolant temperature adjusting means 40 compares the measured temperature T2 with the target cooling temperature T1, and determines whether T2 = T1. And in the case of YES, the valve opening of the proportional two-way valve 38A where T2 = T1 is maintained and the process ends. If NO, the process proceeds to step 8.

  In step 8, the coolant temperature adjusting means 40 compares the measured temperature T2 with the target cooling temperature T1, and determines whether T2 <T1. In the case of YES, it means that the mixing ratio of the heating liquid to be mixed with the cooling liquid is still too small. Therefore, the process returns to step 6 to control the opening degree of the proportional two-way valve 38A to be further increased. In the case of NO, it means that the mixing ratio of the heating liquid to be mixed with the cooling liquid has become too small, so that the control returns to step 1.

  Thereby, the wafer mounting table 12 is cooled to the target cooling temperature T1. Incidentally, when the target cooling temperature T1 is set to −47 ° C. and the cooling liquid temperature T2 in the state where the heating liquid is not mixed is set to −52 ° C., the present invention consumes 400 W compared to the case where the conventional inline heater is used. Energy saving effect.

  According to the cooling control apparatus and cooling control method for a wafer mounting table of the present invention described above, the following effects can be obtained.

  (1) In the present invention, the cooling liquid adjusted to a temperature lower than the target cooling temperature is mixed with the heating liquid heated by the condensation heat of the refrigerator line 34 that has been exhausted conventionally, thereby controlling the target cooling temperature. I did it. Thereby, this invention can reduce the power consumption for inline heater use compared with the past.

  (2) Further, in the present invention, the cooling liquid and the heating liquid, which are the same heat medium (for example, water), are directly mixed by the mixing ratio adjusting means 38 (for example, the proportional two-way valve 38A), so that the target cooling temperature is controlled. Good control response. For example, even when the deviation between the above measured temperature T2 and the target cooling temperature T1 is large, the target of the target is simply changed by controlling the valve opening of the proportional two-way valve 38A (for example, fully opened) and changing the mixing ratio of the cooling liquid and the heating liquid. Cooling temperature can be achieved.

  (3) Further, the present invention feeds the cooling liquid of the mounting table cooling line 24 and the heating liquid of the heating line 36 with one liquid feeding pump 42, and the mounting table cooling line 24 and the heating line 36 A constant pressure valve 82 is provided between them, and the discharge pressure of the liquid feed pump 42 is set to be larger than the set pressure of the constant pressure valve 82. Thereby, the pressure fluctuation of the cooling liquid flowing through the mounting table cooling line 24 and the heating liquid flowing through the heating line 36 is reduced and the flow is stabilized, so that the mixing ratio of the cooling liquid and the heating liquid can be controlled with high accuracy.

  (4) In the present invention, the refrigerator line 34 is a two-way refrigeration circuit in which two refrigerators of a high temperature side circuit 50 and a low temperature side circuit 52 are combined via a first heat exchanger 48. Configured. Thereby, since the temperature fluctuation of the refrigerant | coolant in the refrigerator line 34 can be made small, the coolant temperature of the mounting base cooling line 24 can be controlled with high precision. Therefore, the mixing ratio of the cooling liquid and the heating liquid can be controlled with high accuracy.

  (5) As a result, it is possible to increase the accuracy and speed of response without using an in-line heater, and thus provide a temperature control device, a temperature control method, and a prober for a wafer mounting table that are more energy-saving than before. be able to.

  DESCRIPTION OF SYMBOLS 10 ... Probe, 12 ... Wafer mounting base, 14 ... Probe, 16 ... Probe card, 18 ... Temperature control apparatus, 20 ... Heater, 22 ... Cooling mechanism, 24 ... Mounting base cooling line, 26 ... Control part, 28 ... Mounting base temperature detecting means, 30 ... tester body, 32 ... connection section, 34 ... refrigerator line, 36 ... heating line, 38 ... mixing ratio adjusting means, 38A ... proportional two-way valve, 40 ... coolant temperature adjusting means, 42 DESCRIPTION OF SYMBOLS ... Liquid feed pump, 44 ... Cooling coil, 46 ... Coolant temperature detection means, 48 ... 1st heat exchanger, 50 ... Low temperature side circuit, 52 ... High temperature side circuit, 54 ... 1st compressor, 56 ... 1st condensation 58 ... 1st expansion valve, 60 ... 1st evaporator, 62 ... 2nd compressor, 64 ... 2nd condenser, 66 ... 2nd expansion valve, 68 ... 2nd evaporator, 70 ... 2nd heat exchange 72 ... Cooling fan, 74 ... Third heat exchanger, 74A ... Heat exchange Coil, 74B ... heating coil, 78 ... outward path of heating line, 80 ... return path of heating line, R ... branch point, S ... confluence

Claims (5)

In the temperature control device for a wafer mounting table equipped with a cooling mechanism for cooling the wafer mounting table for mounting a semiconductor wafer to a target cooling temperature,
The cooling mechanism is
A mounting table cooling line for circulating a coolant to the wafer mounting table;
A refrigerating machine line having a heat pump type refrigerating machine in which the refrigerant circulates, and cooling the cooling liquid to a temperature lower than the target cooling temperature by exchanging heat between the refrigerant and the cooling liquid of the mounting base cooling line; ,
A heating line for joining the heating liquid obtained by heating the cooling liquid divided from the outlet side of the wafer mounting table with the condensation heat generated when the refrigerant is liquefied in the condenser of the refrigerator line to the inlet side of the wafer mounting table When,
A mixing ratio adjusting means for adjusting a mixing ratio of the cooling liquid circulating through the mounting table cooling line and the heating liquid combined from the heating line to the inlet side of the wafer mounting table;
A coolant temperature detecting means for detecting a coolant temperature on the inlet side of the wafer mounting table;
And a cooling liquid temperature adjusting means for controlling the mixing ratio adjusting means so as to reach the target cooling temperature based on a measurement result of the cooling liquid temperature detecting means. . The cooling liquid of the mounting table cooling line and the heating liquid of the heating line are fed by a single liquid feed pump, and the heating liquid of the heating line joins the cooling liquid of the mounting table cooling line Provide a constant pressure valve upstream of the point,
The temperature control device for a wafer mounting table according to claim 1, wherein a discharge pressure of the liquid feeding pump is larger than a set pressure of the constant pressure valve.   The temperature control device for a wafer mounting table according to claim 1 or 2, wherein the refrigerator line is a two-way refrigeration circuit in which two refrigerators of a low temperature side circuit and a high temperature side circuit are combined via a heat exchanger. In the temperature control method of the wafer mounting table for cooling the wafer mounting table on which the semiconductor wafer is mounted to the target cooling temperature,
Heat exchange is performed between the coolant that is circulated to the wafer mounting table and the coolant that is cooled by a heat pump refrigerator that circulates the coolant to form a low-temperature coolant that is lower than the target cooling temperature. A low-temperature coolant forming step;
Heating that forms a heating liquid having a temperature higher than the target cooling temperature by heating the cooling liquid divided from the outlet side of the wafer mounting table by condensation heat generated when the refrigerant is liquefied by the condenser of the refrigerator. A liquid forming step;
A coolant temperature detecting step of detecting a coolant temperature on the inlet side of the wafer mounting table;
A mixing step of mixing the low-temperature cooling liquid and the heating liquid so that the cooling liquid temperature on the inlet side of the wafer mounting table becomes the target cooling temperature based on the measurement result of the cooling liquid temperature detection step. A method for controlling the temperature of a wafer mounting table. The multiple semiconductor devices formed on the mounted semiconductor wafer on the wafer mounting base in order to inspect a tester, the prober to connect each terminal of the tester to the electrodes of the semiconductor device,
A prober comprising the temperature control device according to claim 1 on the wafer mounting table.

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