JP2008190739A - Cooling device and semiconductor inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling device which restrains the occurrence of trouble due to solidification of a refrigerant or impurity in the refrigerant, and has favorable reliability of temperature control and simple constitution, and also to provide a semiconductor inspection device using the cooling device. <P>SOLUTION: In this cooling device, the refrigerant cooled by a refrigerator is circulated in a cooling object. The cooling device includes: a temperature detection means for detecting the temperature of the refrigerant; an adjusting valve for adjusting the quantity of the refrigerant cooled by the refrigerator; a refrigerant temperature control means for controlling the opening and closing the adjusting valve according to the temperature of the refrigerant detected by the temperature detecting means to control the temperature of the refrigerant; and an adjusting valve forced opening and closing means for controlling the opening and closing operation at least at intervals of a predetermined period regardless of the temperature of the refrigerant. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cooling device for circulating a refrigerant cooled by a refrigerator to a cooling target and a semiconductor inspection device using the cooling device.

  With recent miniaturization and higher performance of semiconductor devices, for example, inspection of semiconductor devices is often performed at the wafer level. In addition, since it is necessary to accurately control the substrate temperature in the above inspection, it is common to control the temperature of the substrate by combining a heating unit and a cooling unit.

  For example, in order to control the temperature of the substrate, a holding table that holds the substrate, a heating unit that heats the holding table, and a cooling unit that cools the holding table are used to control heating and cooling of the holding table. Thus, the substrate temperature is controlled to a desired value. For example, as a cooling means for the holding table, a cooling device (chiller) that circulates a refrigerant through the holding table is used.

  In addition, the holding table needs to be electrically isolated when performing an electrical test of the semiconductor device. For this reason, a substantially insulating material (high resistance material), for example, a fluorine-based liquid is generally used as the refrigerant circulated to the holding table.

  However, when the above-described refrigerant is cooled to 0 ° C. or lower and used, impurities such as water mixed with the refrigerant may solidify to cause a problem in circulating the refrigerant. For example, the cooling amount of the refrigerant is controlled by opening and closing a flow rate adjusting valve formed in a flow path for circulating the refrigerant. When impurities (for example, ice) solidified on the flow rate adjusting valve adhere to the flow rate adjusting valve, it may hinder the opening and closing of the flow rate adjusting valve, making accurate temperature control of the refrigerant difficult.

For example, in order to solve the problem of the malfunction of the regulating valve, a cooling device to which a structure for supplying dry air is added (for example, see Patent Document 1) or a cooling to which a filter for trapping ice is added. An apparatus (see, for example, Patent Document 2) has been proposed.
JP 2006-203992 A JP 2006-203991 A

  However, when a structure or a filter for supplying dry air to the cooling device is added, there is a concern that the configuration of the cooling device becomes complicated and the manufacturing cost of the cooling device increases. Therefore, in the present invention, the overall problem is to solve the above problems.

  A specific problem of the present invention is a cooling device that suppresses the occurrence of defects due to solidification of the refrigerant or impurities in the refrigerant, has a reliable temperature control, and has a simple configuration, and a semiconductor using the cooling device It is to provide an inspection device.

  In the first aspect of the present invention, the above problem is a cooling device for circulating the refrigerant cooled by the refrigerator to the object to be cooled, the temperature detecting means for detecting the temperature of the refrigerant, and being cooled by the refrigerator. An adjustment valve that adjusts the amount of the refrigerant, refrigerant temperature control means that controls the temperature of the refrigerant by controlling opening and closing of the adjustment valve in response to the temperature of the refrigerant detected by the temperature detection means, This is solved by a cooling device characterized in that the regulating valve has regulating valve forcible opening / closing means for controlling the opening / closing operation at least every predetermined period regardless of the temperature of the refrigerant.

  ADVANTAGE OF THE INVENTION According to this invention, generation | occurrence | production of the malfunction by solidification of the refrigerant | coolant or the impurity in a refrigerant | coolant can be suppressed, the reliability of temperature control is favorable, and the cooling device which is a simple structure can be provided.

  The refrigerant is mainly composed of a fluorinated liquid, and when the temperature controlled by the temperature control means is 0 ° C. to −80 ° C., the refrigerant by the regulating valve forced opening / closing means or impurities in the refrigerant The effect of suppressing the occurrence of defects due to solidification is increased.

  In addition, when the predetermined period is 5 seconds or less, solidification of impurities in the refrigerant can be effectively suppressed.

  Moreover, it is preferable that the period during which the regulating valve is opened by the regulating valve forced opening / closing means is 5% or less of the predetermined period.

  According to a second aspect of the present invention, the above-described problems are solved by the above cooling device, and a substrate holding table that holds the substrate to be processed on which the semiconductor device is formed while the coolant is circulated by the cooling device. And a heating means installed on the substrate holding table.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the cooling device which suppresses generation | occurrence | production of the malfunction by solidification of the refrigerant | coolant or the impurity in a refrigerant | coolant, has favorable reliability of temperature control, and is a simple structure.

  The cooling device according to the present invention is a cooling device for circulating the refrigerant cooled by the refrigerator to the object to be cooled, and adjusts the amount of the refrigerant cooled by the temperature detecting means for detecting the temperature of the refrigerant and the refrigerator. An adjusting valve for controlling the temperature of the refrigerant by controlling opening and closing of the adjusting valve in response to the temperature of the refrigerant detected by the temperature detecting means, and the adjusting valve includes the refrigerant And a regulating valve forcible opening / closing means for controlling the opening / closing operation to be performed at least every predetermined period regardless of the temperature of the cooling device.

  For example, in the case where the control by the refrigerant temperature control means, that is, the opening / closing of the adjustment valve is controlled only by the feedback of the refrigerant temperature, for example, when the coagulum such as ice is caught in the adjustment valve, the adjustment valve is completely It becomes difficult to close.

  The refrigerant temperature control means tries to close the adjustment valve so as to increase the temperature of the refrigerant (so that the temperature of the refrigerant does not decrease too much), but the adjustment valve cannot be closed by ice. The temperature will continue to drop.

  Therefore, the above cooling device is provided with the regulating valve forcible opening / closing means. The regulating valve forced opening / closing means controls the regulating valve so that the opening / closing operation is forcibly performed at least every predetermined period regardless of the temperature of the refrigerant. For this reason, it is possible to crush or remove a solidified substance such as ice that hinders the operation of the regulating valve, and it is possible to accurately control the temperature of the refrigerant.

  Next, a more specific example of the embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram schematically illustrating a cooling device 300 according to the first embodiment and a semiconductor inspection device 400 using the cooling device 300. Referring to FIG. 1, the outline of a semiconductor inspection apparatus 400 includes a substrate temperature control unit 100 that holds a substrate W on which a semiconductor device is formed and controls the temperature of the substrate W (semiconductor device), and a substrate temperature control unit. 100 includes a chamber 200 in which the substrate 100 is installed, and a cooling device 300 for circulating a coolant (liquid) for controlling the temperature of the substrate in the substrate temperature control unit 100. In addition, the cooling device 300 and the chamber 200 are connected by a pipe 307 so that the refrigerant can be circulated. In addition, such a cooling device 300 may be called a chiller.

  First, regarding the substrate temperature control unit 100 described above, the substrate temperature control unit 100 has a substrate holding base 101 for holding a substrate W to be inspected on which a semiconductor device is formed. The substrate holding table 101 is formed with a circulation path 104 through which a coolant for controlling the temperature of the substrate W (substrate holding table 101) is circulated.

  For example, the coolant cooled by the cooling device 300 described later is circulated in the circulation path 104, and the temperature control of the substrate W is performed. The substrate holding table 101 is controlled to a predetermined temperature by heat exchange between the refrigerant and the substrate holding table 101, and the temperature control of the substrate W is performed. As the refrigerant, it is preferable to use a fluorine-based liquid that has a low freezing point and does not decrease in viscosity even at low temperatures. Further, since the fluorine-based liquid has a large electrical resistance value and is a substantially insulating material, the substrate holder 101 for performing the electrical property test is surrounded by the surrounding (for example, the grounded chamber 200). It is suitable for electrical isolation from.

  Further, the substrate temperature control unit 100 (substrate holding base 101) is provided with a heating means 105 made of, for example, a heater. For example, when the cooled refrigerant is circulated through the circulation path 104, the temperature control range is increased by using the heating unit 105 in combination with the substrate temperature control.

  Further, the chamber 200 having the substrate temperature control unit 100 therein has a moving unit (not shown), and the substrate temperature control unit 100 (substrate holding base 101) is moved in a predetermined direction by the moving unit. The semiconductor device can be connected to a connection needle for connecting to a tester. In addition, a flexible pipe 201 that circulates a medium connected to the substrate temperature control unit 100 is installed inside the chamber 200, and is configured to correspond to the movement of the substrate holding table 101.

  Next, a cooling device 300 that circulates a coolant for temperature control in the substrate temperature control unit 100 will be described. The outline of the cooling device 300 has a structure including a device main body 309 having a function of cooling and circulating the refrigerant, and a control unit 301 that controls a mechanism inside the device main body 309.

  The apparatus main body 309 includes a refrigerator 302 for cooling the circulating refrigerant, a low-temperature tank 304 that holds a medium cooled by the refrigerator 302, and a flow rate adjustment that adjusts a flow rate flowing from the refrigerator 302 to the low-temperature tank 304. A valve 303 and a circulation pump 305 that circulates the medium held in the low temperature tank 304 to the refrigerator 302 and circulates the medium to the substrate temperature control unit 100 are housed. Further, the temperature of the refrigerant in the low temperature tank 304 is detected by the temperature detecting means 308. In addition, a relief valve 306 is provided for returning the refrigerant discharged from the circulation pump 305 to the suction port side of the circulation pump 305.

  In the above structure, the cooling amount of the refrigerant by the refrigerator 302 is controlled by opening and closing the adjustment valve 303. That is, when the flow rate flowing from the refrigerator 302 to the low temperature tank 304 increases, the cooling amount of the refrigerant increases. Conversely, when the flow rate flowing from the refrigerator 302 to the low temperature tank 304 decreases, the cooling amount of the refrigerant decreases.

  The control unit 301 includes a CPU (computer) 301A that controls the overall operation of the cooling device 300, a recording medium 301B, an input unit 301C, and a display unit 301D. Moreover, the control part 301 has the refrigerant | coolant temperature control means 301F controlled by CPU301A. The refrigerant temperature control unit 301F performs an operation of controlling the temperature of the refrigerant by controlling the opening and closing of the regulating valve 303 in accordance with the temperature of the refrigerant detected by the temperature detection unit 308 described above. The cooling device 300 according to the present embodiment is characterized in that the control unit 301 further includes a regulating valve forced opening / closing means 301E in addition to the refrigerant temperature control means 301F.

  For example, when the control of the regulating valve 303 is controlled only by the control of the refrigerant temperature control means 301F, that is, the feedback of the refrigerant temperature, for example, when the coagulated material such as ice is caught in the regulating valve 303, the regulating valve 303 is completely It becomes difficult to close.

  When ice is caught in the regulating valve 303 as described above, the refrigerant cooled from the refrigerator 302 to the low temperature tank 304 continues to flow, and the temperature of the refrigerant detected by the temperature detecting means 308 continues to decrease. Become. The refrigerant temperature control means 303 tries to close the adjustment valve 303 so as to increase the temperature of the refrigerant detected by the temperature detection means 308 (so that the temperature of the refrigerant does not decrease too much), but the adjustment valve 303 is closed by ice. As a result, the temperature of the refrigerant continues to decrease and the temperature of the refrigerant becomes uncontrollable.

  Therefore, in the cooling device 300 described above, the regulating valve forced opening / closing means 301E is provided. The regulating valve forced opening / closing means 301E controls the regulating valve 303 so that the opening / closing operation is forcibly performed at least every predetermined period regardless of the refrigerant temperature. For this reason, it becomes possible to crush or remove solidified substances such as ice that hinder the operation of the regulating valve 303, and it is possible to accurately control the temperature of the refrigerant. Details of the control of the adjusting valve 303 will be described later.

  The temperature control of the substrate W by the substrate temperature control unit 100 using the cooling device 300 is performed as follows.

  First, the circulation pump 305 sends out a refrigerant made of a fluorine-based liquid held in the low-temperature tank 304 to the refrigerator 302 and the chamber 200 (substrate temperature control unit 100). The refrigerator 302 cools the refrigerant supplied from the circulation pump 305, and the cooled medium is circulated to the low-temperature tank 304. In this case, the temperature of the refrigerant in the low temperature tank 304 is detected by the temperature detection means 308, and the refrigerant temperature control means 301F controls the opening and closing of the regulating valve 303 in accordance with the detected temperature of the refrigerant. The flow rate of the refrigerant circulated from the refrigerator 302 to the low temperature tank 304 is controlled by opening and closing the adjustment valve 303, and the temperature of the refrigerant is controlled.

  Further, the refrigerant sent from the circulation pump 305 to the chamber 200 passes through the supply side of the pipe 307 and is supplied to the circulation path 104 via the supply side of the flexible pipe 201. As the medium circulates in the circulation path 104, heat exchange is performed between the substrate holding base 101 and the refrigerant, and the substrate holding base 101 is controlled to a desired temperature. Further, the refrigerant after the heat exchange is circulated from the circulation side of the flexible pipe 201 to the low temperature tank 304 through the circulation side of the pipe 307.

  In this way, the substrate W held on the substrate holder 101 is controlled to a desired temperature necessary for inspection of the electrical characteristics of the semiconductor device.

  For example, in the case of a test of electrical characteristics of a general semiconductor device, a semiconductor substrate (for example, a 300 mm wafer) on which a semiconductor device is formed is controlled to about −55 ° C. to + 150 ° C. In this case, the refrigerator 302 cools the refrigerant corresponding to the control of the substrate temperature. For example, the above-mentioned refrigerant is set to a low temperature of 0 ° C. or lower, for example, preferably 0 ° C. to −80 ° C., more preferably −30 ° C. to −80 ° C., in order to support the test in the low temperature region of the substrate W.

  FIG. 2 is a diagram schematically showing an open (OPEN) signal and a close (CLOSE) signal by the refrigerant control means 301F when the regulating valve 303 is controlled by the refrigerant temperature control means 301F. The horizontal axis indicates the elapsed time, and one scale is 1 second. The refrigerant temperature control unit 301F controls the opening degree of the adjustment valve 303 to 20%, 60%, or the like, for example, corresponding to the temperature detected by the temperature detection unit 308.

  For example, when the opening degree of the regulating valve is set to 20%, the regulating valve 303 is only in the first 20% period in the period (hereinafter, a predetermined period) which is a control unit of the regulating valve 303. Control to open. For example, when the predetermined period is 5 seconds, the adjustment valve 303 is opened only for the first 20% period (1 second) immediately after the start of the predetermined period, and the remaining 80% period (4 seconds) of the predetermined period is closed. Thus, the regulating valve 303 is controlled. After the end of the first predetermined period, the control for the predetermined period is repeatedly performed.

  Similarly, when the opening degree of the regulating valve is 60%, the regulating valve 303 is opened for the first 60% period (3 seconds) in the predetermined period (5 seconds), and the remaining period in the predetermined period. The regulating valve 303 is controlled so as to be closed during a period of 40% (2 seconds). After the end of the first predetermined period, the control for the predetermined period is repeatedly performed.

  That is, the regulating valve 303 is controlled by controlling the ratio of the open period of the predetermined period which is a unit of control, and the control of the predetermined period is repeated. Will be controlled.

  3A to 3C are diagrams schematically showing the operation of the valve body of the regulating valve 303 described above. 3A shows a state where the regulating valve 303 is closed, FIG. 3B shows a state where the regulating valve 303 is opened, and FIG. 3C shows a state where ice is caught in the regulating valve 303.

  First, referring to FIG. 3A, the valve body V closes the opening of the casing C so that refrigerant does not pass through the opening. In this case, the valve body C is pressed against the opening by an elastic body S made of a spring or the like. In the state shown in FIG. 3B, the valve body C is pushed downward against the elastic force of the elastic body S, for example, by electromagnetic force such as a solenoid or by pressing with gas, and the refrigerant is in the casing C. It is possible to pass through the opening. In controlling the temperature of the refrigerant, the states shown in FIGS. 3A and 3B are repeated.

  On the other hand, as shown in FIG. 3C, when ice K is sandwiched between the valve body V and the casing C, the valve body V cannot block the opening of the casing C. In this case, the cooled refrigerant continues to be supplied from the refrigerator 302 to the low temperature tank 304, and the temperature of the refrigerant continues to decrease. When the temperature of the refrigerant decreases, the refrigerant temperature control means 301F tries to close the regulating valve 303 in response to the temperature detected by the temperature detection means 308, but it becomes difficult to close because of the ice K, and the temperature of the refrigerant It becomes difficult to control.

  Therefore, in the cooling device 300 according to this embodiment, as described above, the adjustment valve forcible opening / closing means 301E is provided in addition to the refrigerant temperature adjustment means 301F.

  FIG. 4 shows the control of the regulating valve 303 by the conventional cooling device (in which the regulating valve forcible opening / closing means 301E is omitted in the cooling device 300, shown as “conventional example” in the drawing) and the cooling device 300 according to the present embodiment. It is the figure compared. The horizontal axis indicates the elapsed time, and one scale indicates 1 second. In both the conventional example and the present embodiment, it is assumed that the control is performed so that the predetermined period is 5 seconds and the opening of the regulating valve is 20% (the first 1 second is OPEN).

  Referring to FIG. 4, for example, in the case of the conventional example, when ice clogging occurs in the adjustment valve, the refrigerant temperature adjustment means 301 </ b> F cannot close the adjustment valve 303. For this reason, the refrigerant temperature adjusting means 301F continues to generate a CLOSE signal in an attempt to close the adjustment valve 303. However, since the refrigerant temperature continues to decrease, ice growth is promoted and the adjustment valve is difficult to return. (Period T1 in the figure).

  On the other hand, in the case of the present embodiment, even if ice clogging occurs in the regulating valve 303, the regulating valve 303 does not depend on the temperature of the refrigerant detected by the temperature detecting unit 308, but the regulating valve forced opening / closing means. By 301E, it is forcibly opened simultaneously with the start of the predetermined period at least every predetermined period (for example, 5 seconds), and the state shown in FIG. 3B is obtained. That is, the valve body V of the adjustment valve 303 is moved to one end substantially to the end of the stroke on the open side. After that, since the regulating valve 303 is closed, it is possible to crush or remove a solidified substance such as ice that hinders the operation of the regulating valve 303 (period T1a in the figure). After the period T1a elapses, the control of the regulating valve 303 returns to the normal control by the refrigerant temperature control means 301F (period T2).

  In addition, if the period during which the regulating valve 303 is forcibly opened (hereinafter referred to as “forced opening period”) is too long, the temperature of the refrigerant is too low and it takes time for the refrigerant to return to a normal temperature. The period is preferably 5% or less of the predetermined period, and the forced release period is more preferably 1% or less of the predetermined period.

  FIG. 5 is a diagram showing changes in the temperature of the refrigerant when the set temperature of the refrigerant (the target temperature for control) is changed in the cooling device 300. For example, in period A, after the refrigerant is maintained at a set temperature of 25 ° C. for a certain period, the set temperature of the refrigerant is changed to −55 ° C. Therefore, the temperature of the refrigerant changes from 25 ° C. to −55 ° C. from the period B to the period D.

  6 to 9 are diagrams showing signals for controlling the regulating valve 303 in a conventional cooling device (those in which the regulating valve forced opening / closing means 301E is omitted from the cooling device 300). 6 corresponds to the period A, FIG. 7 corresponds to the period B, FIG. 8 corresponds to the period C, and FIG. 9 corresponds to the period D. In FIGS. 6 to 9, the OPEN signal and the CLOSE signal are also connected by a line for easy understanding of the drawings.

  6 to 9, the opening degree of the regulating valve 303 increases when the actual refrigerant temperature is away from the set temperature (target temperature) of the refrigerant, and the actual refrigerant temperature and the refrigerant setting are set. Control is performed so as to decrease as the temperature difference decreases (PID control). As described above, the temperature of the refrigerant is mainly controlled by repeatedly opening (OPEN) and closing (CLOSE) the regulating valve 303. However, as shown in FIG. When the temperature is significantly higher than the set temperature of the refrigerant, the refrigerant temperature control means 301F keeps the adjustment valve 303 open (opening degree 100%) in order to increase the cooling amount of the refrigerant.

  In the above period B, the adjustment valve 303 is held open for a long time, and the temperature of the refrigerant rapidly decreases, so that ice clogging in the adjustment valve 303 is particularly likely to occur.

  On the other hand, the control signal of the regulating valve 303 corresponding to the period B in the cooling device 300 according to the present embodiment is shown in FIG. In the cooling device 300, the regulating valve forced opening / closing means 301E described above is forcibly opened / closed at least every predetermined period regardless of the temperature of the refrigerant. For this reason, it becomes possible to control the temperature of the refrigerant accurately by suppressing the occurrence of ice clogging in the regulating valve 303.

  In addition, if the predetermined period, that is, the period from when the regulating valve is closed once to the next closing is too long, the probability that ice grows increases. For example, the refrigerant is controlled by using a fluorinated liquid as a main component. When the temperature (the temperature of the refrigerant in the low temperature tank 304) is 0 ° C. to −80 ° C., the predetermined period is preferably 5 seconds or less.

  FIG. 11 shows measured values of the temperature of the substrate holder 101 and the temperature of the refrigerant circulated by the cooling device 300 in the semiconductor inspection apparatus shown in FIG. In this case, the control target temperature of the substrate holder 101 is 25 ° C., the temperature of the refrigerant in the low temperature tank 304 is 17.5 ° C., the predetermined period is 5 seconds, and the forced opening time of the regulating valve 303 is 1 of the predetermined period. % (0.05 seconds).

  Referring to FIG. 11, the temperature of the refrigerant rapidly decreases at the beginning of the period t <b> 1 in FIG. 11, and the temperature of the substrate holding base 101 decreases substantially correspondingly. It is thought that ice clogging occurred. However, after that, the temperature of the refrigerant rapidly recovers, and is substantially constant after the elapse of the period t1 while repeating the vertical movement. Corresponding to the return of the temperature of the refrigerant, the temperature of the substrate holder 101 is also returned to a substantially constant value.

  This is considered to indicate that the ice formed in the regulating valve 303 has been removed by the forcible opening / closing operation of the regulating valve 303 described above independent of the refrigerant temperature. Further, if the predetermined period is 5 seconds or more, the vertical movement of the temperature change of the substrate holding base 101 is further increased, or the period of time during which the temperature change of the substrate holding base 101 is large (period t1) is further increased. Conceivable. For this reason, it is understood that the predetermined period is preferably 5 seconds or less.

  Although the present invention has been described with reference to the preferred embodiments, the present invention is not limited to the specific embodiments described above, and various modifications and changes can be made within the scope described in the claims.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the cooling device which suppresses generation | occurrence | production of the malfunction by solidification of the refrigerant | coolant or the impurity in a refrigerant | coolant, has favorable reliability of temperature control, and is a simple structure.

It is a figure which shows the cooling device by Example 1, and the semiconductor inspection apparatus using the said cooling device. FIG. 2 is a diagram (part 1) illustrating an example of control of a regulating valve used in the cooling device of FIG. FIG. 3 is a diagram (part 1) illustrating an operation of a valve body of the regulating valve in FIG. 2; FIG. 3 is a diagram (part 2) illustrating the operation of the valve body of the regulating valve in FIG. 2. FIG. 6 is a diagram (part 3) illustrating the operation of the valve body of the regulating valve in FIG. 2; It is a figure which shows the difference in control of the cooling device by a prior art example and Example 1. FIG. It is a figure which shows the temperature change of the refrigerant | coolant of a cooling device. It is FIG. (The 1) which shows control of the conventional cooling device. It is FIG. (2) which shows control of the conventional cooling device. It is FIG. (The 3) which shows control of the conventional cooling device. It is FIG. (The 4) which shows control of the conventional cooling device. FIG. 6 is a diagram (No. 3) illustrating an example of control of a regulating valve used in the cooling device of FIG. 1. It is a figure which shows the effect of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Substrate temperature control part 101 Substrate holding stand 104 Circulation path 105 Heating means 200 Chamber 201 Flexible piping 300 Cooling device 301 Control means 301A CPU
301B Recording medium 301C Input means 301D Display means 301E Control valve forced opening / closing means 301F Refrigerant temperature control means 302 Refrigerator 303 Flow rate adjustment valve 304 Low temperature tank 306 Relief valve 307 Piping 308 Temperature detection means 309 Device body

Claims (5)

A cooling device for circulating a refrigerant cooled by a refrigerator to a cooling target,
Temperature detecting means for detecting the temperature of the refrigerant;
A regulating valve for regulating the amount of the refrigerant cooled by the refrigerator;
Refrigerant temperature control means for controlling the temperature of the refrigerant by controlling opening and closing of the regulating valve in response to the temperature of the refrigerant detected by the temperature detection means;
A cooling device comprising: a regulating valve forcibly opening and closing means for controlling the regulating valve to perform an opening / closing operation at least every predetermined period irrespective of the temperature of the refrigerant.   The cooling device according to claim 1, wherein the refrigerant is mainly composed of a fluorine-based liquid, and the temperature of the refrigerant controlled by the temperature control means is 0 ° C to -80 ° C.   The cooling apparatus according to claim 2, wherein the predetermined period is 5 seconds or less.   The cooling device according to claim 3, wherein a period during which the regulating valve is opened by the regulating valve forced opening / closing means is 5% or less of the predetermined period. The cooling device according to any one of claims 1 to 4,
A substrate holding table for holding the substrate to be processed on which the semiconductor device is formed and the coolant is circulated by the cooling device;
And a heating means installed on the substrate holder.

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