JPH0722402A - Processing device control method - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a control method for preventing pressure fluctuations in a processing chamber due to a cold leak of a supply refrigerant. [Structure] The refrigerant supplied from Rox 11 is recooled by a subcooler 13 to stabilize the pressure, and then the mounting table 4 is placed.
To the cooling jacket 8. A pressure detecting means 80 is provided downstream of the subcooler 13, and the detected pressure value and its change rate are calculated, and when both of them exceed a predetermined value, the valve means 84 is temporarily shut off. Then, the supply of the refrigerant is stopped. With such a control method, it is possible to prevent pressure fluctuations in the processing chamber and failure of the processing device due to inflow of the leaked refrigerant into the processing chamber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a processing apparatus, and more particularly to a method for controlling a processing apparatus for processing an object to be processed in a low temperature atmosphere.

[0002]

2. Description of the Related Art In a technique for treating an object to be processed using a reactive gas plasma, for example, a dry etching technique, an object to be processed, for example, a semiconductor wafer is cooled in order to obtain a vertical pattern shape and a high selection ratio. It is known that an etching process is performed in a low temperature atmosphere. For this reason, conventionally, a refrigerant storage portion is formed on the mounting table of the object to be processed, and a refrigerant is supplied to the refrigerant storage portion from an external refrigerant system, and the heat transfer reduces the temperature of the reaction surface of the object to be processed. The low temperature processing technology is widely used.

By the way, a high frequency power source is connected to the mounting table in which the coolant accommodating portion is formed as described above, and high frequency power is applied during processing so that the mounting table is used as a cathode electrode. Therefore, it is structurally required that the connection portion with the coolant supply system that supplies the coolant to the coolant storage portion of the mounting table, which is the lower electrode, has excellent electrical insulation, heat insulation, and strength.

[0004]

However, in order to meet the above-mentioned performance requirements, in the above-mentioned joint portion, an insulating material such as Teflon or ceramics and a metal material such as stainless steel having excellent strength even in a low temperature atmosphere are used. I had no choice but to use the material. Therefore, due to the difference in heat shrinkage rate between different materials during cooling, a gap is created at the fusion point of the different materials, and the supply refrigerant leaks from the gap (so-called cold leak), and in some cases the leaked refrigerant enters the processing chamber. This may affect the pressure in the inflow processing chamber, resulting in deterioration of the function of the processing apparatus or failure, which may adversely affect the yield or throughput of the product.

The present invention has been made in view of the above problems of the conventional low temperature processing apparatus. The purpose of the present invention is to provide a stable supply of the refrigerant to the mounting table and to prevent a cold leak. Detecting an abnormality in the refrigerant supply system before the refrigerant leaking from the refrigerant supply system due to other factors affects the function of the processing device or causes the processing device to malfunction,
It is an object of the present invention to provide a new and improved processing apparatus control method that is capable of stopping the supply of the refrigerant and is excellent in fail-safe.

[0006]

In order to solve the above-mentioned problems, according to the present invention, a mounting member for mounting and fixing an object to be processed in an airtight processing chamber that can be adjusted to a desired reduced pressure atmosphere. In a processing device for processing an object to be processed in a low temperature atmosphere by circulating a refrigerant between a refrigerant accommodating portion formed on a table and an external refrigerant supply system, the refrigerant accommodating system supplies the refrigerant accommodating portion to the refrigerant accommodating portion. The pressure stabilizing means for holding the supply pressure of the refrigerant to be constant is provided, the pressure detecting means for detecting the supply pressure of the supply refrigerant is provided on the downstream side, and the supply pressure of the refrigerant detected by the pressure detecting means When a calculation unit for calculating the change rate is provided, the pressure value detected by the pressure detection unit exceeds a predetermined value, and the change rate of the pressure value calculated by the calculation unit exceeds a predetermined value, Refrigerant Control method of a processing apparatus, characterized by stopping the cut off and the coolant supply to the coolant accommodating portion is provided.

[0007]

According to the control method of the processing apparatus constructed according to the present invention, the refrigerant supply pressure which is kept constant by the pressure stabilizing means is detected by the pressure detecting means, and the refrigerant detected by the pressure detecting means is detected. When both the pressure value of the supply and the rate of change of the pressure value exceed a predetermined value, the refrigerant supply to the refrigerant accommodating portion of the mounting table is shut off, so the cold leak of the refrigerant affects the function of the processing device. It is possible to detect in advance and avoid giving. As a result, since the refrigerant can be supplied to the refrigerant accommodating portion of the mounting table at a stable pressure, the object to be processed can be accurately cooled, and the leaked refrigerant flows into the processing chamber and becomes the processing pressure. Since the coolant supply can be shut off before the influence is exerted, stable low temperature etching can be carried out.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A case where a method for controlling a processing apparatus according to the present invention is applied to a plasma etching apparatus will be described below with reference to the accompanying drawings.

First, an etching apparatus 1 to which the method of the present invention can be applied will be briefly described with reference to FIG. As shown in the figure, the etching apparatus 1 has a substantially cylindrical airtight processing chamber 2 made of a conductive material such as aluminum, and an exhaust port 3 is provided near the bottom of the processing chamber 2. It is provided so that the inside of the processing chamber 2 can be evacuated to a desired depressurized atmosphere via an exhaust means (not shown) such as a vacuum pump.

Further, a substantially column-shaped mounting table 4 is housed in substantially the center of the processing chamber 2 so as to maintain an electrically insulated state from the bottom of the processing chamber 2. An object to be processed, for example, a semiconductor wafer W can be mounted on the upper surface of the mounting table 4. The mounting table 4 is composed of, for example, a substantially columnar susceptor support 5 made of aluminum, and a susceptor 7 made of aluminum, which is detachably provided on the support 5 with bolts 6.

The susceptor support 5 is provided with a coolant containing portion, for example, a cooling jacket 8 for circulating and circulating a coolant, for example, liquid nitrogen. This cooling jacket 8 is provided with a refrigerant supply passage 9 and a refrigerant discharge passage 10, and as shown in FIG. 1, a refrigerant source 11, for example, Rox, and a suitable pipe through a gas-liquid separator 12 and a subcooler 13. The coolant, for example liquid nitrogen, supplied by the means 14, for example, the vacuum double-insulated pipe is introduced from the coolant supply passage 9 into the cooling jacket 8, circulates therein, and through the coolant discharge passage 10. The gas is discharged and released to the outside of the system via the evaporator 15.

The susceptor 7 is in the shape of a disk having a convex portion in the center thereof, and a fixing means for mounting and fixing the semiconductor wafer W on the mounting surface of the central convex portion, for example, electrostatic. A chuck 16 is provided. This electrostatic chuck 16
Is formed by sandwiching a conductive film 17 such as a copper foil between two polyimide films.
By applying a high voltage from the DC high voltage source 19 via the filter circuit 18, it is possible to generate a Coulomb force on the chuck surface and suck and hold the semiconductor wafer W on the mounting surface. Further, on the mounting surface of the susceptor 7, a heat transfer gas supply means 20 for supplying a heat transfer medium such as helium gas to the back surface of the mounted semiconductor wafer W is installed.

Further, on the peripheral edge of the upper end of the susceptor 7,
An annular focus ring 2 that surrounds the semiconductor wafer W
1 is arranged. The focus ring 21 is made of an insulating material that does not attract reactive ions, and the reactive ions are incident only on the semiconductor wafer W placed inside to improve the efficiency of the etching process.

The susceptor 7 is provided with a pipe lead 22 formed of a hollow-shaped conductor and penetrating the susceptor support 5. With this pipe lead 22, high-frequency power of, for example, 380 KHz is applied from the high-frequency power source 25 to the susceptor 7, which is also the lower electrode, via the noise-cutting filter 23 and the matching capacitor 24, and plasma is generated in the processing chamber. It is configured to be able to.

Above the susceptor 7, a grounded upper electrode 26 is provided. The inside of the upper electrode 26 is configured to be hollow, and a large number of small holes 27 are formed in the surface facing the semiconductor wafer W that is the object to be processed. A processing gas sent through a mass flow controller (not shown), for example, an etching gas such as CF ₄ can be uniformly introduced into the processing chamber.

A temperature adjusting heater 29 is provided between the susceptor 7 and the susceptor support 5, and electric power is applied to the temperature adjusting heater 29 from a power source 30 via a filter 31 to generate a heating source. By acting as
It is possible to optimally adjust the amount of cold heat transferred to the semiconductor wafer W from the cooling jacket 8 provided in the susceptor support 5.

Further, the electrostatic chuck 16 is provided with temperature detecting means 32 for detecting the temperature of the semiconductor wafer W, such as a Luxtron or a thermocouple, and the temperature detected by the temperature detecting means 32 is It is sent to the control unit 34 through the filter 33, and for example, the temperature adjustment heater 2
9 is used to control the output. As mentioned above,
The plasma etching apparatus 1 to which the method for controlling a processing apparatus according to the present invention can be applied is configured.

Now, the processing apparatus 1 configured as described above.
The cooling jacket 8 in the mounting table 4 of the
In order to supply the refrigerant from 0, between the refrigerant supply port 35 of the cooling jacket 8 and the refrigerant supply passage 9 and the refrigerant discharge port 3
A joint device 51 as disclosed in, for example, Japanese Patent Application No. 4-353046 filed by the same applicant as the applicant of the present application is interposed between 6 and the refrigerant discharge passage 10, and the susceptor support 5 and The bottom wall of the processing chamber and the refrigerant passages 9 and 10 are electrically insulated from each other, and the leakage of cold heat into the processing chamber is prevented.

Next, the structure of the joint device 51 as described above will be briefly described with reference to FIGS. 3 and 4. 3 and 4, only the structure of the joint device 51 on the refrigerant supply side is enlarged and shown, but the joint device on the refrigerant discharge side also has the same structure, and therefore the details thereof will be described here. Detailed description is omitted.

As shown in FIG. 3, this joint device 51 has an accommodating portion side coupling portion 52 which has a flow passage in the center and is inserted and attached to the refrigerant accommodating portion 8, and has low thermal conductivity and electrical conductivity. The accommodating portion-side coupling portion 5 is made of a highly insulating material, for example, ceramics obtained by firing alumina or the like, and has a flow path in the center.
2 is mainly connected to the insulating heat insulating intermediate portion 53, and the refrigerant passage side coupling portion 54 that has a flow path in the center and is connected to the insulating heat insulating intermediate portion 53 and is connected to the refrigerant supply path 9. Composed.

The accommodating portion side coupling portion 52 is made of a conductive material such as aluminum which is inserted into the cooling jacket 8 at the upper part thereof and is liquid-tightly attached and fixed to the partition wall of the jacket 8 as a whole. A tip member 55, a ring member 56 made of stainless steel or the like which is connected thereto by a friction welding method, and a relaxation member 57 made of Kovar or the like connected to the ring member by an electron beam welding method. It is configured by connecting to a layered structure. Then, the insulating heat insulating intermediate portion 53 formed in a ring shape is connected to the relaxing member 57 by, for example, a vacuum brazing method, and the action of the intermediate portion 53 insulates against high frequency and heat against liquid nitrogen.

Further, the refrigerant passage side joint portion 54 connected to the heat insulating intermediate portion 53 has a vacuum double tube structure made of, for example, stainless steel, and is connected to the upper end portion thereof by, for example, butt welding. A relaxing member 58 made of, for example, Kovar is provided, and this relaxing member 58 is connected to the intermediate portion 53 by, for example, a vacuum brazing method. Further, an auxiliary heat insulating member 59 made of, for example, Teflon is fitted in the lower peripheral portion of the relaxing member 58.

The refrigerant passage side coupling portion 54 has a vacuum double heat insulating structure. This double piping structure is concentric with an inner pipe 60 made of, for example, stainless steel and a predetermined distance apart from the inner pipe 60. And an outer pipe 61 made of, for example, stainless steel.

The upper portion of the outer pipe 61 is connected to a joining member 62 made of, for example, stainless steel, and the joining member 62 has an annular space formed between the inner pipe 60 and the outer pipe 61, that is, a vacuum chamber. 63 and processing room 2
A communication passage 64 is formed for communicating with and. With such a structure, by vacuuming the inside of the processing chamber 2 during processing, it is possible to simultaneously bring the vacuum chamber 63 into a vacuum state and prevent cold heat from being transmitted to the outside.

The above-mentioned inner pipe 60 and outer pipe 61
A lower joining member 65 made of, for example, stainless steel, in which a flow path 64 is formed in the central portion, is provided at the lower end of the double insulation pipe 9 of the refrigerant supply system 50, which will be described later, and the joint device 51. The connection with is made.

Next, referring to FIG. 4, by using the joint device 51 having the above-described structure, the above-mentioned refrigerant system having a vacuum double heat insulation piping structure composed of an outer pipe 67 and an inner pipe 68 made of, for example, stainless steel or the like. A connection state between the pipe 9 and the cooling jacket 8 of the processing device 1 will be described.

The lower part of the joint device 51 is housed in a recess-shaped penetration assisting member 70 fixed to a step-like through hole formed in the bottom 69 of the processing chamber by means of bolts or the like. A ring-shaped flow path 71 that connects the processing chamber 2 and the vacuum chamber 63 is formed between the and the outer peripheral surface of the joint device. A portion A where the processing chamber bottom portion 69 and the joining member 62 are in contact with each other
Sealing members 73 and 72 for blocking ventilation from the outside are respectively provided at a portion B where the recess-shaped penetration assisting member 70 and the joining member 62 are in contact with each other.

On the other hand, the upper end of the inner pipe 68 of the pipe 9 of the refrigerant supply system 50, through which the refrigerant flows, is joined to the lower end portion of the flow path 64 of the lower joining member 65 so that the refrigerant is connected to the joint device 51. Of the inner pipe 60. And the refrigerant supply system pipe 50
At the upper end of the inner pipe 68 of the outer pipe 6 of the joint device 51 via a flange-shaped auxiliary member 77.
An inner auxiliary stainless steel pipe 75 is provided so as to surround 1. The upper ends of the inner auxiliary stainless steel pipe 75 and the outer pipe 67 are hermetically connected to the bottom 69 of the processing chamber at a portion C by a seal member 66, for example, via a flange 76 made of stainless steel. Regarding the lower end of the inner auxiliary stainless steel pipe 75 and the upper end of the inner pipe 68 of the pipe 9,
A ring-shaped Teflon seal 74 provided under the lower joining member 65 is airtightly connected at the portion D. In this way, the annular space 78 formed between the inner auxiliary stainless steel pipe 75 and the outer pipe 61 of the joint device 51 is configured to be airtight from the outside by the portions C and D.

As described above, the refrigerant supply system 50
The refrigerant supplied from the inside of the inner pipe 68 of the pipe 9 flows through the inside of the inner pipe 60 of the joint device 51 to the passage formed without leakage, and the refrigerant is supplied. The cooling jacket 8 through the mouth 35
It is introduced into the inside and is used as a cold heat source for cooling the reaction surface of the semiconductor wafer W which is the object to be processed to a desired temperature. At this time, normally, the portions A, B, C and D are liquid-tightly sealed by the seal members 73, 72, 66 and 74, respectively, so that the outer pipe 6 of the cooling jacket 8 is
The refrigerant does not leak into the space 78 formed between the inner auxiliary stainless steel pipe 75 and the inner auxiliary stainless steel pipe 75.

However, the refrigerant used has a very low temperature such as −196 ° C. in the case of liquid nitrogen, and the thermal expansion of the joints and seals of the respective pipes for supplying the refrigerant. Different materials with different rates,
For example, since Teflon and stainless steel have to be used, a minute clearance is formed in the seal portions A, B, C and D due to stress during repeated use or due to freezing of water which is condensed in a minute gap. It may happen.

As a result, the refrigerant sent in the inner pipe 68 of the pipe 9 passes through the seal 74 at the portion D and is formed between the outer pipe 61 of the joint device 51 and the auxiliary stainless pipe 75. Space 78
And in parts C, B and A,
Passing through the seals 66, 72 and 73, respectively, the inner pipe 60 and the outer pipe 61 of the joint device 51
There is a case where the gas leaks into the processing chamber 2 through the passages 79 and 71 for vacuuming the space 63 formed between the space 63 and the space. Therefore, the refrigerant leaked into the processing chamber 2 is vaporized in the depressurized atmosphere of the processing chamber and changes the pressure in the processing chamber, which may adversely affect the function of the processing apparatus, and when the amount of leakage is great, The processing device itself may be damaged or damaged.

The present invention has been made in order to prevent such a situation. Therefore, in the present invention, a pressure stabilizing means for keeping the supply pressure of the refrigerant in the refrigerant supply system 50 constant, for example, the subcooler 13 is used. Is provided, pressure detection means 80 for detecting the supply pressure of the supply refrigerant is provided on the downstream side thereof, and further operation means 81 for calculating the change rate of the supply pressure of the refrigerant detected by the pressure detection means 80 is provided. When the pressure value detected by the detection means 80 exceeds a predetermined value and the rate of change of the pressure value calculated by the calculation means 81 exceeds a predetermined value, the refrigerant system is shut off and the cooling jacket 8 is opened. The control method of stopping the refrigerant supply is adopted.

Next, a system configuration for applying the above control method will be described with reference to FIG. As shown in the figure, the refrigerant contained in the Rocks (liquid nitrogen cylinder) 11, for example, liquid nitrogen, is sent to the gas-liquid separator 12 by the vacuum double adiabatic piping 14 via the valve means 82, where the gas-phase liquid phase is changed. To be separated. In this way, the vacuum double heat insulation pipe 14
Therefore, when a refrigerant, for example, liquid nitrogen is transferred, heat input from the outside is suppressed, but it is still present, and it is difficult to avoid gasification of the liquid-phase refrigerant to some extent. Furthermore, the saturated vapor pressure decreases due to the pressure loss in the piping, and the refrigerant to be phase-shifted repeats evaporation in order to lower the liquid temperature.

When the liquid nitrogen transferred in the pipe in such a state is introduced by opening the valve at the point of use, it is jetted in a gas-liquid mixed state, and its control becomes extremely difficult. Therefore, according to the present invention, the refrigerant supply system 5
Set the subcooler 1 to the position of 0 as close to the processing device 1 as possible.
3 is provided to stabilize the refrigerant supply pressure. This point will be described with reference to FIGS. 5 and 6.

As shown in FIG. 5, the subcooler 13 is
A heat exchange coil 84, in which a hollow thin tube is circulated stepwise, is housed in a hollow cylindrical dewar 83 having an upper portion open to the atmosphere. The dewar 83 is filled with liquid nitrogen, and the refrigerant in the gas-liquid mixed state sent in the introduction path α is heat-exchanged and recooled in the thin tube of the heat exchange coil 84, and the discharge path β. Is discharged as supercooled liquid in. That is, the subcooler 13
Is part of liquid nitrogen at atmospheric pressure saturation temperature (-196 ℃), heat exchange liquid nitrogen under atmospheric pressure with liquid nitrogen in the pipe, supercooled liquid (pressure inside the pipe is higher than atmospheric pressure). Therefore, it is possible to make the saturation temperature -196 ° C or higher).

In this way, the transfer refrigerant is transferred to the subcooler 13 described above.
By setting the supercooled state by
In the diagram, the P-V state of the transfer refrigerant can be shifted from the α position to the β position, evaporation of the transfer refrigerant can be suppressed, and flash loss at the point of use can be reduced. As a result, it becomes possible to introduce the refrigerant into the cooling jacket 5 with a stable pressure,
The control becomes easy.

Returning to FIG. 1 again, the refrigerant made into the supercooling liquid by the subcooler 13 is introduced and circulated from the pipe 9 into the cooling jacket 8 through the joint device 51, discharged from the pipe 10, and evaporated. It is discharged to the outside through the container 15. In this case, according to the present invention, the pressure detector 80 monitors the supply pressure of the refrigerant, and the detected value is sent to the arithmetic circuit 81 and compared with a preset reference value. At the same time, the pressure detector 83
The pressure inside the chamber is monitored by, and the detected value is sent to the arithmetic circuit 81. Further, in the arithmetic circuit 81, the rate of change of the supply pressure value is appropriately calculated and compared with a preset reference value.

As described above, when so-called cold leak occurs in the joint device 51 portion, it is known that the supply pressure of the refrigerant rises and the rate of increase thereof is rapid. In the invention, such a phenomenon is used as a criterion for operating the safety mechanism when a cold leak occurs. That is, in the present invention, the upper limit value of the allowable supply pressure and the upper limit value of the allowable supply pressure change rate are set in advance, and the pressure value detected by the pressure detection means 80 and calculated by the calculation circuit 81 and the change rate thereof are calculated. When both upper limit values of the above are exceeded, a shutoff signal is sent to the valve means 8 provided upstream of the subcooler 13.
4, the supply of the refrigerant is temporarily cut off. By such an operation, it is possible to prevent a situation in which the cold leak seriously affects the processing pressure in the processing chamber 2 or the processing device 1 itself is broken or destroyed.

In the above example, the pressure value detected by the pressure detector 80 and the change value of the pressure calculated by the arithmetic circuit 81 are used as the criterion for judging the interruption of the refrigerant supply. It is also possible to use the pressure value in the processing chamber 2 to be used as a criterion for control. The above is the description regarding the operation of the control method of the processing apparatus configured according to the present invention.

Finally, the operation of the plasma etching apparatus to which the method of controlling the processing apparatus constructed according to the present invention can be applied will be briefly described. The semiconductor wafer housed in the cassette chamber (not shown) is transferred to a load lock chamber (not shown) by a predetermined transfer arm, and a predetermined pressure, for example, 1 × 10 ⁻⁴ from this load lock chamber is passed through the gate valve.
~ Mounting table 4 in the processing chamber 2 decompressed to about several tens Torr
After being placed on the placing surface of the susceptor 6 of
It is adsorbed and held by 6.

During this period, a coolant, for example, liquid nitrogen, is supplied from the coolant supply system 50 shown in FIG. 1 into the cooling jacket 8 via the pressure stabilizer or the subcooler 13, and the heat of cold from there is transferred to the semiconductor wafer for processing. The surface is cooled to the desired temperature. This temperature is measured by the temperature sensor 32 at any time.
Is detected by the control unit 34, and the control unit 34 operates the heating unit 29 or the like based on the detection signal to maintain a predetermined temperature.

At this time, a cold leak occurs in the joint device 51 portion, and the leaked refrigerant flows into the processing chamber 2,
If there is a risk of changing the pressure in the processing chamber 2,
According to the control method of the present invention, the valve means 84 provided in the refrigerant supply system is temporarily shut off using the pressure value detected by the pressure detecting means 80 and the rate of change of the pressure value as the criterion. It is possible. As a result, it is possible to prevent the pressure fluctuation in the processing chamber 2 and the failure or destruction of the processing device due to the cold leak of the supplied refrigerant.

In this way, the processing gas such as HF ₄ is supplied from the small hole 27 of the upper electrode 26 into the processing chamber 2 kept in the optimum processing environment, and the high frequency power source 2
High frequency power is applied to the susceptor 7, which is the lower electrode, from 5 to generate plasma in the processing chamber 2, and the desired etching process is performed on the processing surface of the semiconductor wafer W.

After the etching process is completed, after the residual processing gas and reaction products in the processing chamber are sufficiently exhausted, the semiconductor wafer W is carried out by the transfer arm to the load lock chamber and further to the cassette chamber through the gate valve. A series of processing ends. The above is a series of operation explanations regarding one embodiment of the plasma etching apparatus to which the control method according to the present invention can be applied.

In the above-mentioned embodiment, as an example, the method of controlling the processing apparatus according to the present invention is applied to the plasma etching apparatus, but the method of the present invention is not limited to such an apparatus, and a CVD apparatus, an ashing apparatus, etc. In the case of inspecting a sputtering apparatus or an object to be processed at a low temperature, it can be applied to, for example, a sample mounting table of an electron microscope or a cooling mechanism of a sample mounting table for evaluating semiconductor materials and elements.

[0046]

As described above, according to the control method of the processing apparatus constructed according to the present invention, the refrigerant supply pressure held constant by the pressure stabilizing means is detected by the pressure detecting means, and the When both the pressure value of the refrigerant supply detected by the pressure detection means and the rate of change of the pressure value exceed a predetermined value, the refrigerant supply to the refrigerant accommodating portion of the mounting table is shut off, so that the refrigerant is cold. It is possible to detect in advance and avoid that the leak affects the function of the processing device. As a result, since the refrigerant can be supplied to the refrigerant accommodating portion of the mounting table at a stable pressure, the object to be processed can be accurately cooled, and the leaked refrigerant flows into the processing chamber and becomes the processing pressure. Since the coolant supply can be shut off before the influence is exerted, stable low temperature etching can be carried out.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a refrigerant supply system to which a control method of a processing apparatus configured according to the present invention can be applied.

FIG. 2 is a schematic cross-sectional view of a plasma etching apparatus to which a method for controlling a processing apparatus configured according to the present invention can be applied.

FIG. 3 is a cross-sectional view showing an embodiment of a joint device applicable to the plasma etching apparatus of FIG.

FIG. 4 is an enlarged cross-sectional view showing a state where the joint device of FIG. 3 is attached to the plasma etching device of FIG.

FIG. 5 is a schematic sectional view of a subcooler to which the present invention can be applied.

6 is a P-V diagram showing the function of the subcooler of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 processing apparatus 2 processing chamber 4 mounting table 5 susceptor support 7 susceptor 8 cooling jacket 9 refrigerant supply path 10 refrigerant discharge path 11 rocks 12 gas-liquid separator 13 subcooler 14 vacuum double heat insulation pipe 15 evaporator 50 refrigerant supply system 51 joint Device 80 Pressure detection means 81 Arithmetic circuit 84 Valve means

Claims (1)

[Claims] 1. In a processing chamber which is airtight and can be adjusted to a desired depressurized atmosphere, a refrigerant is introduced between a refrigerant accommodating portion formed on a mounting table for mounting and fixing an object to be processed and an external refrigerant supply system. In the processing device for processing the object to be processed in a low temperature atmosphere by circulating, a pressure stabilizing means for holding the supply pressure of the refrigerant supplied to the refrigerant accommodating section constant in the refrigerant supply system, A pressure detecting means for detecting the supply pressure of the supply refrigerant is provided on the downstream side, and a calculating means for calculating the change rate of the supply pressure of the refrigerant detected by the pressure detecting means is further provided, and the pressure detected by the pressure detecting means. When the value exceeds a predetermined value and the rate of change of the pressure value calculated by the calculating means exceeds the predetermined value, the refrigerant system is shut off and the refrigerant supply to the refrigerant accommodating portion is stopped. When Control method of that processing unit.