JP4191120B2 - Plasma processing equipment - Google Patents

Description

  The present invention relates to a plasma processing apparatus applied to fine processing such as a semiconductor manufacturing process, and more particularly to a plasma processing apparatus having a holding stage for mounting a semiconductor wafer.

  In recent years, with the high integration of semiconductors, circuit patterns have been increasingly miniaturized, and the accuracy of required processing dimensions has become increasingly severe. In addition, there is a demand for improving throughput and responding to an increase in the area of an object to be processed such as a semiconductor wafer. Therefore, the electric power input to the plasma processing apparatus tends to increase. In particular, in a plasma processing apparatus that etches an insulating film, there is a tendency to increase the electric power input when generating plasma in order to increase the etching rate. Here, since most of the electric power supplied to the plasma processing apparatus becomes heat, for example, an electrostatic adsorption electrode (holding stage) that controls the temperature of a semiconductor wafer or the like with high accuracy has high efficiency and a large capacity. A temperature control unit (cooling device) is required. In addition, the temperature control unit is required to have not only high efficiency but also a small environmental impact load with a small installation area.

  By the way, the temperature control of the semiconductor wafer or the like in the plasma processing apparatus is generally realized by controlling the surface temperature of the electrostatic adsorption electrode, and a method for dealing with such temperature control during the processing has been proposed. Yes. That is, in the conventional electrostatic adsorption electrode, temperature control is performed by circulating a heating medium in an electrode block that is a constituent member of the electrostatic adsorption electrode. The heating medium to be circulated is generally an inert fluorine-based liquid, and is cooled by a refrigeration cycle using, for example, chlorofluorocarbon, or heated by a heater and maintained at a predetermined temperature. In such a temperature control unit that circulates the heating medium, the temperature variation can be reduced because of the heat capacity of the circulating heating medium itself, but on the other hand, the temperature response is deteriorated. In addition, since the temperature of the heating medium is controlled via a heat exchanger, there is waste in terms of heat efficiency, and the apparatus becomes large because a pump for circulating the heating medium is also necessary due to the configuration of the apparatus. (For example, refer to Patent Document 1).

For this reason, a temperature control unit that circulates by directly connecting propane gas, which is a refrigerant, directly into an electrostatic adsorption electrode without using a fluorine-based inert heating medium has been proposed (for example, a patent) Reference 2).
JP 2001-257253 A JP 2003-174016 A

  The above prior art does not consider the temperature adjustment unit of the electrostatic adsorption electrode, and has a problem in that the temperature control of the electrostatic adsorption electrode is realized with high efficiency and high accuracy.

  For example, in the temperature control unit that circulates the heat medium described in Patent Document 1, as described above, the heat medium is controlled to a predetermined temperature via the heat exchanger in the temperature control unit, so that the heat efficiency is poor, In addition, a pump for circulating the heating medium is also necessary. In addition, a large amount of heating medium is required and the temperature response is also deteriorated.

  On the other hand, in the method disclosed in Patent Document 2, a detailed structure relating to the electrostatic adsorption electrode is not described. For example, if the refrigerant is circulated directly in the electrostatic adsorption electrode, there is a concern that the pressure of the refrigerant is high, so that the electrode block is deformed into a convex shape.

An object of the present invention is to provide a plasma processing apparatus capable of performing an adjustment and processing temperature of the semiconductor wafer during processing with high efficiency.

In order to solve the above problems, the present invention includes a processing chamber internal plasma is the vacuum is formed, a dielectric on the surface for holding the wafer to be processed using the plasma disposed in the treatment chamber A holding stage that includes an electrode block having a film and in which a coolant channel is formed, holds the wafer via a dielectric film on the surface of the electrode block, and controls the temperature; the coolant channel and a compressor; A refrigeration cycle comprising a condenser and an expansion valve connected to circulate the refrigerant and use the metallic member as an evaporator of a refrigeration cycle in which the refrigerant is heated and vaporized, Another heating means for the refrigeration cycle to heat the refrigerant was provided in front of the evaporator of the refrigeration cycle .

Further, according to the present invention, in the plasma processing apparatus, the operation of the another heating unit is adjusted so as to reduce a temperature difference of the holding stage before and after the start of the plasma processing .

According to the present invention, in the plasma processing apparatus, the heating of the refrigerant is stopped in a state where the another heating unit generates the plasma .

Hereinafter, a plasma processing apparatus according to the present invention will be described in detail with reference to the drawings.
[Configuration of plasma processing apparatus]

  FIG. 1 is a cross-sectional view of a plasma processing apparatus according to an embodiment of the present invention. The plasma processing apparatus shown in FIG. 1 includes a processing chamber 100, an antenna 101 that radiates electromagnetic waves in the upper part thereof, and a holding stage S on which a target object such as a semiconductor wafer W is placed in the lower part. The antenna 101 is held by a housing 105 as a part of a vacuum vessel, and the antenna 101 and the holding stage S are installed in a form facing each other in parallel. Around the processing chamber 100, magnetic field forming means 102 made of, for example, an electromagnetic coil and a yoke is installed. The holding stage S is generally called an electrostatic chucking electrode, and therefore will be referred to as an electrostatic chucking electrode S hereinafter.

  The processing chamber 100 is a vacuum container that can achieve a vacuum of about 1 / 10,000 Pa by the vacuum exhaust system 103. A processing gas for performing processing such as etching and film formation on the object to be processed is supplied into the processing chamber 100 from a gas supply unit (not shown) with a predetermined flow rate and mixing ratio, and the processing chamber is operated by the vacuum exhaust system 103 and the exhaust adjustment unit 104. The pressure within 100 is controlled. In general, in a plasma processing apparatus, a processing pressure during etching is often adjusted to a range of 0.1 Pa to 10 Pa or less.

An antenna power source 121 is connected to the antenna 101 via a matching circuit 122. The antenna power supply 121 supplies power of a UHF band frequency from 300 MHz to 1 GHz. In this embodiment, the frequency of the antenna power supply 121 is 450 MHz. A high voltage power supply 106 for electrostatic attraction is supplied to the electrostatic attraction electrode S via a matching circuit 109, and a bias power supply 107 for supplying bias power in the range of 200 kHz to 13.56 MHz, for example , via the matching circuit 108, Each is connected. In this embodiment, the frequency of the bias power source 107 is 2 MHz.
[Configuration of Electrostatic Suction Electrode S]

  FIG. 2 is a perspective view with a partial cross section of the electrostatic chucking electrode S used as a holding stage for the semiconductor wafer W in this plasma processing apparatus. The structure of the electrostatic chucking electrode S will be described in detail using this figure. As shown in FIG. 2, the electrostatic adsorption electrode S includes a titanium heat diffusion plate 2, a titanium guide member 3, a dielectric film 4, and a ceramic electrode cover 5 in a titanium electrode block 1. After the electrode block 1, the plate 2, and the guide member 3 are joined with a low melting point metal brazing material, the dielectric film 4 is adhered to the surface with a silicon-based adhesive.

  The size of the electrostatic chucking electrode S is 340 mm in diameter when the semiconductor wafer of 12 inches (diameter 300 mm) is targeted, and the total thickness is 40 mm. A coolant channel 6 is formed in the electrode block 1, and a metal electrode 7 is embedded in the dielectric film 4. The high voltage power source 106 and the bias power source 107 shown in FIG. 1 are connected to the electrode 7 in the dielectric film 4. As shown in FIG. 2, the dielectric film 4 is provided with linear slits 41 that extend radially and communicate with the gas introduction holes 8, and a plurality of concentric slits 42 that communicate with the linear slits 41. Heat transfer He gas is introduced from the gas introduction hole 8, and the back surface of the semiconductor wafer W is filled with He gas having a uniform pressure (usually about 1000 Pa) through the slit.

  The dielectric film 4 shown in the present embodiment is made of high-purity alumina ceramic having a thickness of 3 mm. The material and thickness of the dielectric film 4 are not limited to this example. In this case, a thickness of 0.1 mm to several mm can be selected accordingly.

The temperature control of the electrostatic adsorption electrode S is performed using the temperature adjustment unit 50. The temperature control unit 50 includes a refrigerant pipe 51 through which refrigerant circulates, a compressor 52, an expansion valve 53, a heat addition unit 54 with a built-in heater, a condenser 55 and a control system 56, and a refrigerant passage 6 that functions as an evaporator. Is done. The control system 56 controls the compressor 52, the expansion valve 53, and the heat addition unit 54 while indirectly or directly monitoring the temperature of the electrode block 1, so that the electrode block 1 reaches a predetermined temperature. Is built-in.
[Temperature control mechanism of electrostatic adsorption electrode]

  Next, the principle of temperature control of the electrostatic adsorption electrode S in this embodiment will be described. The electrostatic adsorption electrode S is for adsorbing the semiconductor wafer W by a Coulomb force or a Johnson Lambeck force that is expressed by applying a high voltage to the dielectric film 4. There are two types of high voltage application methods: a monopolar type and a bipolar type. The monopolar type gives a uniform potential between the semiconductor wafer and the dielectric film, while the bipolar type applies between the dielectric films. Is a method in which two or more potential differences are given. In the present embodiment, the electrode is a single electrode type electrostatic chucking electrode, but not limited to this, any method may be used.

The temperature of the semiconductor wafer W during the etching process is determined by the amount of heat input from the plasma, the thermal resistance in the He layer, and the surface temperature of the electrostatic adsorption electrode S. The surface temperature of the electrostatic adsorption electrode S includes the amount of heat input from the plasma, the thermal resistance in the electrode block 1, the thermal resistance between the refrigerant circulating in the electrode block 1 and the electrode block 1, and the temperature of the circulating refrigerant. It is prescribed by.
[Operation of plasma processing equipment]

  Next, a specific process for etching silicon, for example, using the plasma processing apparatus of this embodiment will be described. In FIG. 1, first, a semiconductor wafer W, which is an object to be processed, is loaded into a processing chamber 100 from a target object loading mechanism (not shown), and then placed and sucked on an electrostatic chucking electrode S. Thus, the height of the electrostatic adsorption electrode S is adjusted and set to a predetermined gap. Next, gases necessary for etching the semiconductor wafer W, such as chlorine, hydrogen bromide, and oxygen, are supplied from a gas supply unit (not shown) and supplied into the processing chamber 100 with a predetermined flow rate and mixing ratio. At the same time, the processing chamber 100 is adjusted to a predetermined processing pressure by the vacuum exhaust system 103 and the exhaust control means 104. Next, electromagnetic waves are radiated from the antenna 101 by supplying power of 450 MHz from the antenna power supply 121. Then, the plasma P is generated in the processing chamber 100 by the interaction with the substantially horizontal magnetic field of 160 gauss (electron cyclotron resonance magnetic field intensity with respect to 450 MHz) formed inside the processing chamber 100 by the magnetic field forming means 102. The gas is dissociated to generate ions and radicals. Furthermore, etching is performed while controlling the temperature of the semiconductor wafer W by controlling the composition ratio and energy of ions and radicals in the plasma by the bias power from the bias power source 107 of the electrostatic adsorption electrode S. Then, along with the end of the etching process, the supply of electric power / magnetic field and processing gas is stopped to end the etching.

The embodiment of the plasma processing apparatus according to the present invention is not limited to the system using the UHF shown here, and other types of plasma processing apparatuses may be used.
[Details of temperature control unit]

  FIG. 3 shows a comparison between a conventional temperature control unit and a temperature control unit according to the present invention. FIG. 3A shows a conventional circulation type temperature control unit, and FIG. 3B shows a temperature control unit 50 according to the present invention.

  The conventional temperature control unit shown in FIG. 3A is a refrigeration unit including a refrigerant pipe 51 through which a refrigerant such as CFC circulates, a compressor 52, an expansion valve 53, a condenser 55, and a heat exchanger 59 that functions as an evaporator. A cycle, a pipe 71 through which a fluorine-based inert heating medium flows, a pump 72 for circulating the heating medium, a heat exchanger 59 for exchanging heat between the refrigerant and the heating medium, and a heater 70 for heating the heating medium Is done. In such a conventional temperature control unit, since the circulating heat medium itself has a heat capacity, the temperature fluctuation can be reduced, but on the other hand, the temperature response is deteriorated. Here, the allowable maximum temperature of the semiconductor wafer W is the heat resistant temperature of the resist formed on the surface, but when the heat input from the plasma increases, the temperature of the surface of the dielectric film 4 in accordance with the amount of heat input, That is, the temperature of the circulating heat medium must be lowered.

However, as shown in FIG. 4, when the temperature of the heating medium decreases, the viscosity of the heating medium increases, so that the heat passage rate with the electrode block 1 decreases. For example, the heat transfer rate of a heating medium at 20 ° C. circulating through a rectangular pipe having a height of 15 mm and a width of 5 mm at 4 L / min is about 800 W / m ² K, but 600 W / m at 0 ° C. Lower to m ² K (recalculation). The same applies to the heat exchanger in the temperature control unit. When the temperature of the heating medium is lowered, the heat efficiency is deteriorated, so that the amount of heat that can be absorbed by the temperature control unit is reduced. For this reason, the temperature of the circulating heating medium may gradually increase.

  On the other hand, the temperature control unit 50 according to the present invention shown in FIG. 3B circulates the refrigerant directly in the electrostatic adsorption electrode S. The supply-side refrigerant pipe 51-1 and the discharge-side refrigerant pipe 51-2. , A compressor 52, an expansion valve 53, a heat addition unit 54 with a built-in heater, a condenser 55, a reserve tank 57, and a control system 56. The temperature control unit 50 is provided with a refrigerant spare tank 57 in order to make the amount of refrigerant circulating constant. The refrigerant absorbs heat by being vaporized in the electrode block 1, and the vaporized refrigerant is pressurized by the compressor 52 (the boiling point is lowered), cooled by the condenser 55 and condensed.

  In the plasma processing apparatus, in order to perform stable etching, it is necessary to set the temperature of the plasma processing chamber 100 and the electrostatic adsorption electrode S before the start of etching to a predetermined value. At this time, the inside of the plasma processing chamber 100 is maintained at a high vacuum, and the electrostatic chucking electrode S is almost insulated. Therefore, when the refrigerant of the temperature control unit 50 is simply circulated, the refrigerant is not vaporized and cannot be set to a predetermined temperature. Therefore, in the temperature adjustment unit 50 shown in the present embodiment, the control system 56 monitors the temperature of the electrostatic adsorption electrode S with the temperature sensor 58 (thermocouple), and the control system 56 outputs the heat addition unit 54 and opens the expansion valve 53. In this system, the temperature is controlled while adjusting the output of the compressor 52 by the degree and the inverter control.

  The heat addition unit 54 does not generate heat when generating plasma. The temperature sensor 58 may monitor the temperature of other members or directly measure the temperature of the refrigerant when a high frequency is directly applied to the electrostatic adsorption electrode S.

In the temperature control unit 50 shown in this embodiment, the temperature control range is slightly narrowed due to the characteristics of the refrigerant, but the electrostatic adsorption electrode S is directly cooled by the refrigerant, so that the thermal efficiency is excellent. In addition, the heat passage rate of the refrigerant in the electrode block is as high as about 5000 W / m ² K at 5 ° C. as compared with the heating medium, and it is not necessary to lower the set temperature as compared with the refrigerant of the conventional device. Thus, the power for operating the temperature control unit 50 can also be reduced.

The heat addition unit 54 shown in the present embodiment has a built-in heater. However, for example, hot water may be flowed instead of the heater, and the supply-side refrigerant as shown in FIG. A bypass pipe 80 that bypasses the electrode block 1 may be provided between the pipe 51-1 and the discharge-side refrigerant pipe 51-2, and temperature control may be performed in combination with the heat addition unit 54.
[Electrode structure to be noted when using a temperature control unit]

  Next, the structure of the electrostatic adsorption electrode S to be noted when using the temperature control unit 50 of the present embodiment will be described. There are two main points to be noted, one of which is the pressure resistance against the refrigerant circulating in the electrode block, and the other is the refrigerant flow path structure considering the thermal characteristics of the refrigerant.

  Since the temperature control unit 50 of the present embodiment is a cooling method that uses vaporization of the refrigerant as compared with the circulation type temperature adjustment unit, the pressure of the refrigerant is high, and an electrode structure that takes into account the deformation of the electrode block 1 is adopted. There is a need. For example, it has been confirmed that if the surface with which the semiconductor wafer W comes into contact is deformed into a convex shape of 0.05 mm or more, the amount of He gas leakage increases and high-precision temperature control cannot be performed. For example, if the pressure of the refrigerant is 5 atm, a load of about 3500 kg is applied to the plane of the electrode block 1. Therefore, in the structure in which only the circumferential portion of the electrode block 1 and the guide member 3 is brazed, Block 1 is deformed into a convex shape.

  From this, in the electrostatic adsorption electrode S of the present embodiment, as shown in FIG. 5, not only the outer periphery of the electrode block 1 but also the side wall 20 of the refrigerant flow path 24 in the electrode block 1 is considered as a rigid member. The structure is brazed 21 with the member 3. The means for fastening the electrode block 1 and the guide member 3 may be brazing, diffusion bonding, or electron beam welding as well as brazing. Further, the guide member 3 is more thermally conductive than the electrode block 1. It may be made of a material with a low rate. The refrigerant is introduced from the refrigerant introduction port 22 into the refrigerant passage 6 and discharged from the refrigerant discharge port 23 through the plurality of refrigerant flow paths 24 between the plurality of side walls 20 provided in parallel. The side wall 20 functions as a heat transfer means between the refrigerant and the electrode block 1 and also functions as a rib that increases the strength of the electrode block 1.

On the other hand, in the flow path structure of the refrigerant, it is necessary to design the structure in consideration of the fact that the circulating refrigerant does not stay and the heat passing rate of the circulating refrigerant . Although the entrance of the refrigerant to that electrodes blocks described refrigerant heat transfer coefficient circulating the electrodes block is a liquid, for vaporizing and absorbs heat with the flowing of the electrode block, the mixing of liquid and gas The rate changes, and the heat passing rate during the inflow changes. Therefore, as shown in FIG. 7, it is only necessary to provide a thermal diffusion plate 2 (aluminum, copper, ALN) having excellent thermal conductivity to make the temperature in the electrode block uniform.

  Further, as an example of a structure in which the refrigerant does not stay, FIGS. 8 and 9 show an example of a flow path structure. In the electrostatic chucking electrode shown in FIG. 8, a rectifying plate 25 is provided in the electrode block so that the refrigerant introduced from the refrigerant introduction port 22 is uniformly dispersed and flows to the refrigerant discharge port 23, and is arranged in a staggered manner. This is an example of the structure in which the cylinder 26 is provided to improve the rigidity.

Further, in the structure shown in FIG. 9, the refrigerant inlet 22 and the refrigerant outlet 23 are arranged close to each other, the annular side walls 20 having a notch in a part thereof are arranged in a concentric manner, and the refrigerant in the circumferential direction is arranged. This is an example of a structure in which multiple channels 24 are provided and adjacent refrigerant channels 24 are connected by a cross channel 27 so that the refrigerant circulates in the circumferential direction.
[Operation when replacing electrostatic adsorption electrode]

The electrostatic adsorption electrode S needs to be replaced because performance (adsorption performance and electrical performance) deteriorates due to etching by plasma and adhesion of deposits during the etching process. The operation of the temperature control unit 50 at the time of when replacing the electrostatic chucking electrode S, is described with reference to FIG. In the temperature control unit 50 shown in the present embodiment, a valve 60 is provided between the supply-side refrigerant pipe 51-1 and the refrigerant introduction port 22 of the electrode block 1, and the refrigerant discharge port 23 of the electrode block 1 and the discharge-side refrigerant pipe 51-. 2 is provided with a valve 61. Further, the temperature control unit 50 includes a gas supply valve 63 such as nitrogen between the valve 60 and the refrigerant introduction port 22 and a discharge valve 62 between the valve 61 and the refrigerant discharge port 23. A pressure sensor 64 and a vacuum pump 65 are provided at the tip of the discharge valve 62.

  The temperature control unit 50 has a built-in vacuum pump and can be in a state in which the electrostatic adsorption electrode S can be automatically replaced and in a state in which it can be automatically operated after being attached.

  When removing the electrostatic adsorption electrode S, the valve 60 is closed in a state where the compressor 52 is operated and the refrigerant is circulated, and after several minutes, the valve 61 is closed. Through this process, all the refrigerant in the refrigerant pipe of the electrode block 1 is recovered to the reserve tank 57. Thereafter, the valve 62 is opened and the vacuum pump 65 is operated at the same time, and the refrigerant pipe in the electrode block 1 of the electrostatic adsorption electrode S is evacuated. At this time, the pressure sensor 64 monitors the pressure in the refrigerant pipe, and after reaching a predetermined pressure, the valve 62 is closed and the valve 63 is opened to introduce nitrogen gas into the refrigerant pipe of the electrode block 1. When the pressure in the refrigerant piping of the electrode block 1 reaches atmospheric pressure, the valve 63 is closed, and it is displayed on the control screen of the plasma processing apparatus that the electrostatic adsorption electrode S can be replaced.

Then, after manually disconnecting the connection between the refrigerant introduction port 22 and the supply side refrigerant pipe 51-1 and the refrigerant discharge port 23 and the discharge side refrigerant pipe 52, removing the electrostatic adsorption electrode S, a new static The electroadsorption electrode S is attached, the refrigerant introduction port 22 and the supply side refrigerant pipe 51-1, and the refrigerant discharge port 23 and the discharge side refrigerant pipe 52 are connected to replace the electrostatic adsorption electrode S.
After replacement of the electrostatic adsorption electrode S, the valve 65 is opened and then the pump 65 is operated. After exhausting the refrigerant pipe in the electrostatic adsorption electrode S, the valve 62 is closed and the valves 60 and 61 are opened. The fact that the temperature control unit 50 is operable is displayed on the control screen of the processing apparatus.
[Confirmation of electrostatic adsorption electrode temperature]

  The temperature of the semiconductor wafer W during plasma discharge was measured using the temperature control unit 50 as described above and the plasma processing apparatus including the electrostatic adsorption electrode S shown in FIG. As a result, the electrostatic chucking electrode during plasma discharge can be set to a predetermined temperature (confirmed in the range of 0 to 10 ° C.), and the power of the bias power source input to the electrostatic chucking electrode S is set to 3000 W. However, it was confirmed that the temperature and reproducibility were good and there was no problem.

The conceptual diagram explaining the structure of the plasma processing apparatus concerning this invention. The figure explaining the structure of the temperature control unit of the plasma processing apparatus concerning this invention. The figure explaining the structure collar of a temperature control unit. The figure explaining the relationship between the temperature of a refrigerant | coolant, and heat transmittance. Sectional drawing explaining an example of the flow path for refrigerant | coolants of an electrostatic adsorption electrode. The figure explaining the structure which enables replacement | exchange of an electrostatic adsorption electrode. Sectional drawing explaining the structure of an electrode block. Sectional drawing explaining the other example of the flow path for refrigerant | coolants of an electrostatic adsorption electrode. Sectional drawing explaining the further another example of the flow path for refrigerant | coolants of an electrostatic adsorption electrode.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Electrode block, 2 ... Thermal diffusion plate, 3 ... Guide member, 4 ... Dielectric film, 5 ... Electrode cover, 6 ... Refrigerant passage, 7 ... Electrode, 8 ... Gas introduction hole, 20 ... Side wall, 21 ... Brazing, 22 ... refrigerant inlet, 23 ... refrigerant outlet, 24 ... refrigerant flow path, 25 ... rectifier plate, 26 ... cylinder, 27 ... transition channel, 41 ... slit, 42 ... slit, 50 ... temperature control unit DESCRIPTION OF SYMBOLS 51 ... Refrigerant piping, 52 ... Compressor, 53 ... Expansion valve, 54 ... Heat addition means, 55 ... Condenser, 56 ... Control system, 57 ... Spare tank, 58 ... Temperature sensor, 59 ... Heat exchanger, 60, 61 DESCRIPTION OF SYMBOLS ... Valve, 62 ... Discharge valve, 63 ... Gas supply valve, 64 ... Pressure sensor, 65 ... Vacuum pump, 100 ... Processing chamber, 101 ... Antenna, 102 ... Magnetic field forming means, 103 ... Vacuum exhaust system, 104 Exhaust control means, 105 ... antenna, 1 6 ... high voltage power supply, 107 ... bias power supply, 108 ... matching circuit, 109 ... filter, 121 ... antenna power, 122 ... matching circuit, P ... plasma, S ... electrostatic chucking electrode, W ... wafer

Claims (4)

A processing chamber in which the inside is evacuated and plasma is formed, and a dielectric film is provided on the surface that holds the wafer that is disposed in the processing chamber and that is processed using the plasma, and a coolant channel is formed in the inside. A holding stage that includes an electrode block and holds the wafer via a dielectric film on the surface of the electrode block to control the temperature, and a flow path of the refrigerant, a compressor, a condenser, and an expansion valve are connected to connect the refrigerant. A refrigeration cycle that circulates and uses the refrigerant flow path of the electrode block as an evaporator of a refrigeration cycle in which the refrigerant is heated and vaporized,
The plasma processing apparatus provided with another heating means for heating the refrigerant in the refrigeration cycle before the evaporator of the refrigeration cycle. The plasma processing apparatus according to claim 1,
The plasma processing apparatus in which the operation is adjusted so that the separate heating means reduces the temperature difference of the holding stage before and after the start of the plasma processing. The plasma processing apparatus according to claim 1 or 2,
The plasma processing apparatus, wherein the heating of the refrigerant is stopped in a state where the plasma is generated by the another heating unit. The plasma processing apparatus according to any one of claims 1 to 3,
The plasma processing apparatus, wherein the another heating means is a heat exchanger provided with a heater .

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