JPH0722403A - Control for treating apparatus - Google Patents

Abstract

PURPOSE:To provide the control method for a treating apparatus, which can prevent the occurrence of cold leak beforehand. CONSTITUTION:In this invention, heating means 22 and 24 for heating parts A and B, where the occurrence of cold leak is expected, are provided. When a treating apparatus 1 is returned from low temperature to normal temperature, the parts A and B are heated with the heating means, and moisture is evaporated and removed from these parts. As the heating method, monitoring is performed with temperature sensors 28 and 29, and heating can be performed for the specified time. Or the temperature sensors are omitted, and heating can be performed based on the experimentally obtained heating output and heating time. Even in when cooling is performed again, the remaining moisture is not frozen and expanded in this control method. Therefore, the cold leak can be effectively prevented.

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, each part of the processing apparatus for performing the above-mentioned low-temperature treatment is not composed of a single kind of material such as aluminum, but the performance required for each part, for example, electrical performance. Insulation, heat insulation, strength,
Various different materials have to be used depending on low temperature resistance and the like, and in some cases, different materials need to be bonded air-tightly or liquid-tight. Therefore, various joining techniques have been conventionally used according to different materials to be joined. For example, aluminum and stainless steel are airtightly or liquid-tightly joined by friction welding, stainless steel and kovar by electron beam welding, and ceramics and kovar by vacuum brazing. .

[0004]

However, none of the above-mentioned joining techniques is perfect, and particularly since the processing equipment is exposed to a severe processing atmosphere such as an ultra-low temperature atmosphere, even if there is a gap or a capillary at the connection point. If there is, for example, water may enter into the gap due to, for example, a capillary phenomenon, and the water may be frozen and thawed repeatedly during the treatment, so that cracks may be generated in the connection portion although the amount is very small. As a result, the refrigerant, such as liquid nitrogen, leaks from the cracked part (so-called cold leak phenomenon), and the pressure in the processing chamber is changed,
The function of the processing device may be deteriorated, and in an extreme case, the processing device may be broken or destroyed.

The present invention has been made in view of the above problems of the conventional low-temperature processing apparatus. Therefore, the object of the present invention is to prevent cold leaks from occurring in each part of the low-temperature processing apparatus. SUMMARY OF THE INVENTION It is an object of the present invention to provide a new and improved control method for a processing device capable of performing stable operation without failure.

[0006]

In order to solve the above-mentioned problems, according to the present invention, a mounting table 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 the processing apparatus for processing the object to be processed in a low temperature atmosphere by circulating the refrigerant between the refrigerant storage portion formed in and the external refrigerant supply system, the portion of the processing apparatus that may cause cold leak is heated. Along with heating means, provided with a temperature detecting means for measuring the temperature of the site, when returning the processing device from the low temperature range to the normal temperature range,
A method for controlling a processing apparatus, characterized in that the heating means heats the part until the temperature detected by the temperature detecting means reaches a preset temperature and / or for a preset time. Provided.

Further, according to another aspect of the present invention, when the temperature detecting means is omitted and the processing device is returned from the low temperature range to the normal temperature range, the heating means presets the portion for a preset time. It can also be configured to heat at a controlled output.

[0008]

According to the method of controlling a processing apparatus constructed according to the present invention, a portion of the processing apparatus where cold leak can occur, for example, a portion where different materials are joined or a portion where a minute gap or a capillary exists. When the processing device is returned from the low temperature range to the normal temperature range, the heating means heats the temperature and the temperature of the part is detected by the temperature detecting means, and / or until the detected temperature reaches a preset temperature, and / or Continue heating for a preset time. Since the set temperature and set time are sufficient to evaporate and remove the moisture adhering to the part to be heated, even if the processing device is used again in the low temperature range, there is a problem. The water does not freeze in the area where it becomes so that it is possible to prevent the occurrence of cold leaks.

Further, according to another aspect of the present invention, the temperature detecting means can be omitted. In that case, the output of the heating means and the heating time for heating the portion where the cold leak is a problem by the heating means to an extent sufficient to remove the water present therein are experimentally determined in advance, and It is possible to effectively evaporate the water content and prevent the occurrence of cold leak at the site by heating with the output set as above for a predetermined time.

[0010]

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. A processing gas inlet 3 is provided near the top of the processing chamber 2, and a predetermined processing gas such as HF ₄ is introduced into the processing chamber 2 from a gas source (not shown) through a mass flow controller (not shown). Is possible. Furthermore, an exhaust port 4 is provided near the bottom of the processing chamber 2 so that the inside of the processing chamber 2 can be evacuated to a desired reduced pressure atmosphere via an exhaust means (not shown) such as a vacuum pump. There is.

Further, a substantially column-shaped mounting table 6 is housed in substantially the center of the processing chamber 2 so as to maintain an electrically insulated state from the bottom portion 5 of the processing chamber 2. Then, the object to be processed, for example, the semiconductor wafer W can be mounted on the upper surface of the mounting table 6. The mounting table 6 is composed of, for example, a substantially cylindrical susceptor support base 7 made of aluminum, and a susceptor 8 made of, for example, aluminum detachably attached to the support base 7.

The susceptor support base 7 is provided with a coolant container, for example, a cooling jacket 9, for circulating and circulating a coolant, for example, liquid nitrogen. The cooling jacket 9 is provided with a refrigerant supply pipe line 10 and a refrigerant discharge pipe line 11, and a pipe means more suitable than a refrigerant source (not shown),
For example, a refrigerant such as liquid nitrogen is introduced from the refrigerant supply passage 10 into the cooling jacket 9 through, for example, a vacuum double-insulated pipe, circulated in the jacket as a cold heat source, and then treated through the refrigerant discharge passage 11. It can be discharged to the outside of the device 1.

The susceptor 8 is in the shape of a disk having a convex portion in the center thereof, and a mounting means for mounting and fixing the semiconductor wafer W on the mounting surface of the central convex portion, for example, electrostatic. A chuck 12 is provided. This electrostatic chuck 12
Is formed by sandwiching a conductive film 13 such as a copper foil between two polyimide films.
By applying a high voltage from the DC high voltage source 14 to
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 8, a heat transfer gas supply means 15 for supplying a heat transfer medium such as helium gas from a gas source (not shown) to the back surface of the mounted semiconductor wafer W is installed.

Further, on the upper peripheral edge of the susceptor 8,
An annular focus ring 1 surrounding the semiconductor wafer W
6 are arranged. The focus ring 16 is made of an insulating material that does not attract reactive ions, and allows the reactive ions generated in the processing chamber 2 to be incident only on the semiconductor wafer W installed inside to improve the efficiency of the etching process. I am trying.

A high frequency power source 18 is connected to the susceptor 8 through a matching capacitor 17, and a high frequency power of, for example, 380 KHz is applied from the high frequency power source 18 to the susceptor 8 constituting the lower electrode. , A structure in which a reactive plasma is generated between it and the top wall 19 of the processing chamber 2 which is grounded to the outside and constitutes an upper electrode, so that the processing surface of the semiconductor wafer W can be etched. Has been done.

A temperature adjustment heater 20 is provided between the susceptor 8 and the susceptor support base 7. By applying electric power from a power source 21 to the temperature adjustment heater 20 to act as a heating source. , The susceptor support 7
It is possible to optimally adjust the amount of cold heat transferred to the semiconductor wafer W from the cooling jacket 9 provided inside. Similarly, heating means 22 is also provided in the peripheral portion of the cooling jacket 9, and by applying electric power from a power source 23 to the heating means 22, a predetermined portion A of the cooling jacket 9, that is, different members Are joined,
There are minute gaps or capillaries, and it is configured so that a site where cold leak can occur can be heated to a predetermined temperature. Further, the refrigerant supply line 10
A heating means 24 is also provided at a predetermined position around the refrigerant discharge pipeline 11, and the heating means 24 is provided with a power source 2
By applying electric power from No. 5, the above-mentioned pipelines 10 and 11
The predetermined part B, that is, different kinds of members are joined to each other, a small gap or a capillary is present, and a part where cold leak may occur can be heated to a predetermined temperature.

Further, in the vicinity of the electrostatic chuck 12, temperature detecting means 26 for detecting the temperature of the semiconductor wafer W,
For example, a Luxtron or a thermocouple is provided, and the temperature detected by the temperature detecting means 26 is the controller 27.
And is used to control the output of the temperature adjusting heater 20, for example. Similarly, a temperature detecting means 28 for detecting the temperature of a predetermined portion A of the cooling jacket 9 is provided near the heating means 22, and the detected value can be sent to the controller 27. Is. Furthermore, the pipes 10, 11 are also provided near the heating means 24.
Temperature detecting means 2 for detecting the temperature of a predetermined portion B of the
9 is provided and the detected value thereof can be sent to the controller 27.

Further, in the cooling jacket 9, there are installed an upper level gauge 30 and a lower level gauge 31 for measuring the level of a refrigerant in the jacket, for example, liquid nitrogen,
It is possible to send information about the water level of the refrigerant to the controller 27 and adjust the supply amount of the refrigerant introduced from the refrigerant supply line 10 into the jacket 9. 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.

As already described, when low-temperature treatment is performed by the above-mentioned treatment apparatus, a portion where different kinds of materials are joined together, for example, a part of the wall portion of the cooling jacket 9 (indicated by symbol A in the figure). ), Or part of the refrigerant supply line 10 and the refrigerant discharge line 11 (indicated by reference numeral B in the figure) may cause so-called cold leak. The present invention prevents the occurrence of such cold leaks and guarantees the operation of the processing device without failure. However, in order to better understand the configuration of the control method according to the present invention, the following will be described with reference to FIG. The mechanism by which cold leak occurs at the joint between different materials will be briefly described with reference to FIG.

As shown in FIG. 2, even in the case where air-tight or liquid-tight joining is made at a joining portion 32 between different materials such as stainless steel 30 and stainless steel 31, a small gap or a capillary 33 is partially formed on the joining surface. Will occur.

When the joint portion having such a capillary 33 is exposed to a gas containing water at room temperature as shown in FIG. 3 and then exposed to a temperature atmosphere in an ultra-low temperature region as shown in FIG. The water contained in is frozen, and the water adheres to the outer surface of the site as frost. After that, when the joint portion is returned to room temperature again as shown in FIG. 5, the frost adhering to the outer surface is melted and appears as water droplets on the surface. The water droplets are sucked into the capillaries at the joints by a so-called capillary phenomenon and remain. When the joint portion is cooled to the ultra-low temperature region again in a state where the capillary contains water as described above, the moisture freezes and expands, and a stress is generated in the direction of separating the joint portion as shown in FIG. When such an operation is repeated, a crack may eventually occur at the joint, and the refrigerant enclosed in the joint, such as liquid nitrogen, may leak. This phenomenon is generally called cold leak.

Next, referring to FIG. 7, the refrigerant supply line 1
The effect of the cold leak on the processing device will be specifically described by taking as an example the case where the cold leak occurs in the 0th portion. As shown in the figure, the refrigerant supply pipeline 10 has a double adiabatic piping structure made of stainless steel, for example. This double adiabatic piping structure is composed of an inner pipe 40 and an outer pipe 41 that covers the inner pipe 40 by opening a predetermined annular space, and the refrigerant supplied from a refrigerant source (not shown) is the inner pipe. It can be introduced into the cooling jacket 9 through the supply port 43 through the passage 42 in 40.
The inner pipe 40 is formed thicker toward the outer periphery in the portion 52 in the bottom portion 5 of the processing chamber.

Further, as a joint portion 43 for connecting the refrigerant supply pipeline 10 to the bottom portion 5 of the processing apparatus 1, a first portion is provided between the inner pipe 40 and the outer pipe 41.
The auxiliary pipe 44 and the second auxiliary pipe 45 of the flange portion 46 formed at a predetermined position of the inner pipe 40.
It is formed so as to be fixed on the same axis so that the leakage of the refrigerant and the dissipation of heat are effectively prevented. As a result of such a configuration, a first annular space 47 is provided between the inner pipe 40 and the first auxiliary pipe 44, and further, the first auxiliary pipe 44 and the second auxiliary pipe 45 are provided. A second annular space 48 is formed between them. The first annular space 47 is temporarily expanded in the circumferential direction along the contour of the thick portion of the inner pipe 40 in the portion 53 in the bottom portion 5 of the processing chamber, and then again on the outer periphery of the inner pipe 40. The portion 54 extends along the vertical direction.

Further, the refrigerant flow path 42 and the first annular space 4
7 and the second annular space 48 are liquid-tightly or airtightly sealed by a suitable sealing member 49. At the same time, the upper end of the second annular space 48 is open to a portion 53 that extends in the outer peripheral direction of the first annular space 47 as shown in the drawing. The opening is liquid-tight or sealed by the sealing member 50. It is hermetically sealed. Further, the first annular space 4
The upper end of 7 is opened to the inside of the processing chamber 2 at the opening 51, and when the processing chamber 2 is evacuated, the inside of the first annular space 47 is also evacuated. It is possible to improve the heat insulation efficiency of the refrigerant flowing through the refrigerant passage 42.

However, in the refrigerant flow path 42, a refrigerant, for example, −
When the operation of introducing liquid nitrogen at 196 ° C. to bring the processing apparatus to an ultralow temperature state and then returning to normal temperature is repeated, for example, the sealing portion 4
9 and 50 may be cracked and cold leaked as described with reference to FIGS. That is,
When the refrigerant is introduced into the flow path 42 in the state where the crack is generated, the refrigerant passes through the sealing portion 49 and leaks into the second annular space 48, and further passes through the sealing portion 50, and then the first annular space. 47
It leaks into the inside of the processing chamber 2 through the opening 51. As a result, the vaporized liquid nitrogen fluctuates the processing pressure in the processing chamber, lowers the function of the processing apparatus, and lowers the product yield and throughput.

The present invention prevents the occurrence of the cold leak as described above, and therefore, the sites where the cold leak is expected to occur, that is, the parts illustrated as part A and part B in FIG. , For example, heating means 22 for heating a portion where different kinds of materials are joined together
And 24 are provided. This heating means 22 and 24
Thus, when the processing device is returned from the ultra-low temperature state to room temperature, it is possible to heat a portion where a cold leak is expected to occur and to evaporate and remove water present at that portion. As a result, water is completely removed from that area,
Even when it is cooled to the ultra-low temperature again, it is possible to effectively prevent a crack from occurring at the site due to the freeze expansion effect of the residual water and a cold leak from occurring through the crack.

As a method of heating a site where cold leak is expected to occur, temperature sensors 28 and 29 for measuring the temperature of the site are installed, and the measured values by the temperature sensors 28 and 29 are preset values, For example, 120 ℃
It is possible to heat until. In that case, it is preferable to continue heating for a certain period of time, for example, 15 minutes, so that water is completely removed from the site.

As another heating method for a site where a cold leak is expected to occur, the output of the heating means and / or the heating time necessary for removing water from the site is experimentally obtained in advance, and the It is also possible to heat the part by a heating means with a predetermined output for a predetermined time based on an experimental value. When such a configuration is adopted, the temperature sensors 28 and 29 can be omitted, so that the structure of the processing apparatus 1 can be simplified. 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 control method of the processing apparatus constructed according to the present invention can be applied will be briefly described. A semiconductor wafer stored in a 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 × 1 is transferred from the load lock chamber through a gate valve 55.
After being mounted on the mounting surface of the susceptor 8 of the mounting table 6 in the processing chamber 2 whose pressure has been reduced to about 0 ⁻⁴ to several tens Torr, the electrostatic chuck 12 suction-holds it.

During this time, a refrigerant from a refrigerant supply source (not shown)
For example, liquid nitrogen is supplied to the inside of the cooling jacket 9 via the coolant supply pipe line 10, and the processed surface of the semiconductor wafer is cooled to a desired temperature by heat transfer of cold heat from the cooling jacket 9. The temperature is detected by the temperature sensor 26 at any time, and the controller 27 operates the heating means 20 and the like based on the detection signal to maintain a predetermined temperature.

At this time, according to the present invention, it is expected that a cold leak will be generated by the heating means 22 and 24 before cooling to an ultra-low temperature, that is, when the processing apparatus previously subjected to the low-temperature processing is returned to room temperature. Since the part to be heated is heated and water is removed from the part in advance, even if low-temperature treatment is performed again, cracks that cause cold leakage due to freezing expansion of the remaining water are generated in the part. It is possible to effectively avoid causing it.

In this way, the processing gas, for example, HF ₄ is supplied from the processing gas supply line 3 into the processing chamber 2 kept in the optimum processing environment, and the susceptor 8 which is the lower electrode from the high frequency power supply 18 is supplied. When high-frequency power is applied to the processing chamber 2, reactive plasma for etching is generated in the processing chamber 2, and the processing surface of the semiconductor wafer W can be subjected to desired etching processing.

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 unloaded to the load lock chamber and the cassette chamber by the transfer arm via the gate valve 55. , 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, the example in which the control method of the processing apparatus according to the present invention is applied to the plasma etching apparatus has been shown as an example, but the method of the present invention is not limited to such an apparatus, and a CVD apparatus and an ashing apparatus are provided. 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.

[0036]

As is apparent from the above description, according to the processing method of the processing apparatus constructed according to the present invention, when the processing apparatus returns from the low temperature state to the normal temperature state, a cold leak is expected to occur. Since it is possible to evaporate and remove water from the part by heating it, the residual water freezes and expands even when the processing device is brought to a low temperature again, and cold leak occurs at that part. It is possible to effectively prevent the generation of such cracks. As a result, it is possible to provide a stable processing device without failure.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a plasma etching apparatus 1 constructed according to the present invention.

FIG. 2 is an explanatory diagram showing how a cold leak occurs.

FIG. 3 is an explanatory diagram showing how a cold leak occurs.

FIG. 4 is an explanatory diagram showing how a cold leak occurs.

FIG. 5 is an explanatory diagram showing how a cold leak occurs.

FIG. 6 is an explanatory diagram showing how a cold leak occurs.

FIG. 7 is a cross-sectional view schematically showing the structure of a refrigerant supply line in which cold leak is expected to occur.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Processing device 2 Processing chamber 6 Mounting table 7 Susceptor support 8 Susceptor 9 Cooling jacket 10 Refrigerant supply conduit 11 Refrigerant transfer conduit 22 and 24 Heating means 27 Controller 28 and 29 Temperature sensor

Claims (2)

[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 a processing apparatus for processing an object to be processed in a low temperature atmosphere by circulating it, a heating means for heating a portion of the processing device that may cause a cold leak is provided, and a temperature detecting means for measuring the temperature of the portion. When the processing device is returned from the low temperature region to the normal temperature region, the heating unit controls the portion until the temperature detected by the temperature detecting unit reaches a preset temperature and / or is set in advance. A method for controlling a processing apparatus, which comprises heating over time. 2. 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 heating means for heating a portion of the processing device that may cause cold leak is provided, and when returning the processing device from the low temperature region to the normal temperature region, A method for controlling a processing apparatus, characterized in that the heating means heats the part at a preset output for a preset time.