JPH11125181A - Temperature control device for cryo-panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust the temperature of a cryo-panel to prevent hydrogen gas emitted at the time of treatment for regeneration from being exploded. SOLUTION: Peltier elements 21 and 22 are used as heating means when a first and a second cryo-panel 15 and 16 are treated for regeneration. A temperature control means 29 controls the temperature of the second cryo-panel 16 to be 25K to 80K as specified so as to emit and exhaust hydrogen when the aforesaid panel is treated. After hydrogen has been completely exhausted, the temperature of the second cryopanel 16 is controlled to be equal to or greater than 80K so as to allow oxygen to be emitted and exhausted. Thus as mentioned above, the occurrence of explosion can be prevented by selectively and individually exhausting hydrogen gas and oxygen gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cryopanel temperature controller for controlling the temperature of a cryopanel of a cryopump.

[0002]

2. Description of the Related Art Conventionally, a cryopump as shown in FIG. 4 has been used for evacuation in a vacuum chamber of a semiconductor manufacturing apparatus or the like. This cryopump 1
A first cryopanel 5 is attached to a first-stage expansion cylinder 3 of a two-stage expansion refrigerator 2 having a two-stage expansion cylinder,
Further, the second cryopanel 6 is attached to the second-stage expansion cylinder 4.
Activated carbon 7 is attached to the inside of the second cryopanel 6, and the entire first and second cryopanels 5 and 6 are formed so as to cover the casing 8. In the cryopump 1 having such a configuration, the opening at the tip of the casing 8 is attached to the exhaust port of the vacuum chamber 9 via a valve (not shown). The water vapor in the vacuum chamber 9 is condensed and exhausted by the first cryopanel 5 cooled to 50K to 80K, and the nitrogen gas and oxygen in the vacuum chamber 9 are condensed by the second cryopanel 6 cooled to 10K to 20K. Gas and argon gas are condensed and exhausted, and activated carbon 7 adsorbs and exhausts hydrogen gas in the vacuum chamber 9.

[0003] When the first and second cryopanels 5 and 6 are filled with the accumulated substances such as oxygen, the first and second cryopanels 5 and 6 are heated and condensed / adsorbed. After discharging the substance, the two cryopanel 5 and 6 are again
A regeneration process for cooling to a low temperature of K is performed. In this case, the temperature of the first and second cryopanels 5 and 6 is increased by a heater having a heating element such as a filament or a resistance element.

[0004]

However, in the above-described conventional cryopump, the temperature of the first and second cryopanels 5 and 6 during the regeneration process is increased by a heater having a heating element such as a filament or a resistance element. There are the following problems to be performed. That is, a heating element such as a filament or a resistance element has a temperature of 100% regardless of the surrounding temperature.
Immediately rises from 200C to 200C. Therefore, when the sheath of the heater is torn, 100 ° C. to 200 ° C.
The hydrogen gas released from the activated carbon 7 of the second cryopanel 6 comes into direct contact with the heating element whose temperature has risen to a certain temperature, and there is a risk of explosion depending on conditions such as the pressure and concentration of the hydrogen gas.

It is an object of the present invention to provide a cryopanel temperature controller capable of controlling the temperature of a cryopanel so that hydrogen gas released during regeneration processing does not explode.

[0006]

Means for Solving the Problems To achieve the above object, the invention according to claim 1 is directed to a cryopump according to the present invention.
A cryopanel temperature controller for adjusting the temperature of a second cryopanel attached to a second-stage expansion cylinder of a step-expansion refrigerator, wherein the cryopanel is attached to the second cryopanel and used for regeneration processing. A peltier element for heating the two cryopanels is provided.

[0007] According to the above configuration, the second cryopanel is heated by the Peltier element during the regeneration process of releasing and exhausting substances such as oxygen condensed / adsorbed on the second cryopanel. In that case, since the Peltier element has a structure for transferring thermal energy, the outside temperature is a temperature that maintains a predetermined temperature difference from the inside temperature attached to the second cryopanel. I have. Therefore, the temperature does not reach 100 ° C. to 200 ° C. irrespective of the ambient temperature, such as a heating element such as a filament or a resistance element. For this reason, when the temperature of the second cryopanel exceeds the boiling point of hydrogen and condensed hydrogen is released as a gas, it does not explode even if it directly touches the Peltier element as a heating source. Absent.

The invention according to claim 2 is a cryopanel temperature controller for adjusting the temperature of a cryopanel in a cryopump having a single-stage expansion refrigerator, wherein the expansion of the single-stage expansion refrigerator is performed. A second cryopanel installed in a first cryopanel mounted on a cylinder, and a Peltier element mounted on the second cryopanel to cool and heat the second cryopanel are provided.

According to the above configuration, the first cryopanel is cooled to 50K to 80K in the single-stage expansion refrigerator, and the steam is condensed and exhausted. Further, the second cryopanel is cooled to 10K to 20K by the Peltier device, and nitrogen gas, oxygen gas and argon gas are condensed and exhausted. In addition, hydrogen gas is adsorbed and exhausted by the activated carbon attached to the second cryopanel. In this case, the heat-resistant temperature of the heat sealing material in the expansion cylinder of the single-stage expansion refrigerator may be about 40K, and the durability time is about twice that in the case of using the two-stage expansion refrigerator.

At the time of the reproduction process, the second cryopanel is heated by the Peltier device. In this case, even if the hydrogen gas discharged to the Peltier element whose surface temperature is higher than the temperature of the second cryopanel by a predetermined temperature does not explode, it does not explode.

According to a third aspect of the present invention, in the cryopanel temperature controller according to the second aspect of the present invention, there are two second cryopanels, and the Peltier element is attached to each of the second cryopanels. It is characterized by being.

According to the above configuration, since the second cryopanel is composed of two cryopanels, a plurality of gases are separated and condensed / adsorbed by the three cryopanels together with the first cryopanel. This facilitates the separation and exhaustion of the condensed / adsorbed substances (particularly, the separation and exhaustion of hydrogen and oxygen) during the above-mentioned regeneration treatment.

According to a fourth aspect of the present invention, in the cryopanel temperature controller according to the second aspect of the present invention, the Peltier element is wound around and attached to the outer periphery of the second cryopanel. And

According to the above configuration, since the Peltier element is wound around the outer periphery of the second cryopanel, cooling and heating of the second cryopanel are performed in a short time.

According to a fifth aspect of the present invention, there is provided the temperature control device for a cryopanel according to the first or second aspect, further comprising a temperature control means for controlling the temperature of the Peltier element. I have.

According to the above configuration, the temperature of the Peltier element can be controlled by the temperature control means.
By sequentially controlling the temperature of the cryopanel so that the boiling point of each substance such as nitrogen, oxygen, argon, and hydrogen passes from below, each of the substances is selectively exhausted.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

<First Embodiment> FIG. 1 is a cross-sectional view (schematic diagram) of a cryopump equipped with a cryopanel temperature controller according to the present embodiment. This cryopump 1
The two-stage expansion refrigerator 12, the first-stage expansion cylinder 13, the second-stage expansion cylinder 14, the first cryopanel 15, the second cryopanel 16, the activated carbon 17 and the casing 18 constituting the first embodiment are shown in FIG. It has the same configuration as the two-stage expansion refrigerator 2, the first-stage expansion cylinder 3, the second-stage expansion cylinder 4, the first cryopanel 5, the second cryopanel 6, the activated carbon 7, and the casing 8 as shown. Works. And
The water vapor in the vacuum chamber 19 is condensed and exhausted by the first cryopanel 15 cooled to 50K to 80K, and
Nitrogen gas, oxygen gas and argon gas in the vacuum chamber 19 are condensed and evacuated by the second cryopanel 16 cooled to ２０20 K, and hydrogen gas in the vacuum chamber 19 is adsorbed and evacuated by the activated carbon 17.

On the outer surfaces of the first cryopanel 15 and the second cryopanel 16, Peltier elements 21 and 22 as heating means are attached. Peltier element 21,
2, has a structure in which a P-type semiconductor 25 and an N-type semiconductor 26 are interposed between two heat absorbing / radiating plates 23 and 24 arranged in parallel at a predetermined interval, as shown in FIG. ing. Then, by controlling the movement of the electrons in the semiconductors 25 and 26 by the electric current, the temperature difference between the heat absorbing and dissipating plates 23 and 24 is controlled. Therefore, for example, in the case of the Peltier element 22 attached to the second cryopanel 16, if the temperature of the second cryopanel 16 is 20 ° C., and if the temperature difference is 65 ° C., the second cryopanel 1
The temperature of the side not attached to 6 becomes 85 ° C.

That is, the Peltier elements 21 and 22 operate so as to have a temperature difference corresponding to the value of the flowing current.
The temperature of one heat absorbing and dissipating plate 23 (24) is
(23), the surface temperature is 100 ° C. to 200 ° C. despite the fact that the ambient temperature is as low as 100 K or less, such as a filament or a resistance element, where the exhaust of hydrogen gas is not completed. It does not reach ℃. Therefore, by using the Peltier devices 21 and 22 as heating means for the first cryopanel 15 and the second cryopanel 16 during the reproduction process, for example, the Peltier device 2 can be used.
Even if the sheaths (not shown) of 1,22 are torn, the released hydrogen gas does not explode because there is no ignition source.

However, if hydrogen gas and oxygen gas are mixed at a certain ratio, an explosion occurs due to sparks due to static electricity or the like even if there is no ignition source. Therefore, it is desirable not to release hydrogen gas and oxygen gas at the same time. Here, the release temperature of hydrogen is 25K or more. On the other hand, the release temperature of oxygen is 8
0K or more. Therefore, in the present embodiment, the temperature sensors 27 and 28 are attached to the outer surfaces of the first cryopanel 15 and the second cryopanel 16 and the first and second cryopanels 15 detected by the two temperature sensors 27 and 28 are provided. , 16 based on the outer surface temperature of the Peltier elements 21, 22.

When the cryopump is stopped, oxygen is condensed on the outer surface of the second cryopanel 16 so that the outer surface temperature of the second cryopanel 16 becomes 80 K or less. After the start of the regenerating process, the temperature control unit 29 controls the outer surface temperature of the second cryopanel 16 to a predetermined temperature of 25K to 80K. By doing so, the hydrogen adsorbed on the activated carbon 17 attached to the inside of the second cryopanel 16 is released and exhausted, but the oxygen condensed on the outer surface of the second cryopanel 16 is not released. As a result, hydrogen gas and oxygen gas are not mixed, and there is no danger of explosion.

The temperature of the second cryopanel 16 is raised to 80 K or more by the temperature control means 29 when the hydrogen adsorbed on the activated carbon 17 on the inner surface of the second cryopanel 16 is completely discharged and exhausted. By doing so, oxygen condensed on the outer surface of the second cryopanel 16 is released and exhausted.

As described above, in the present embodiment, the Peltier elements 21 and 22 are used as the heating means during the regeneration processing of the first and second cryopanels 15 and 16, and the temperature sensor 2 is used.
The temperature of the Peltier devices 21 and 22 can be controlled by the temperature control means 29 based on the detected temperatures of the first and second cryopanels 15 and 16 by the devices 7 and 28. At the time of the regenerating process, the temperature of the second cryopanel 16 is 25K-
The temperature is controlled by the temperature control means 29 so as to reach a predetermined temperature of 80 K, and hydrogen is released and exhausted. In this way, after the hydrogen is completely exhausted, the temperature of the second cryopanel 16 is controlled to 80 K or more to release and exhaust oxygen. Thus, by selectively releasing hydrogen and oxygen separately and exhausting, it is possible to prevent the hydrogen gas and the oxygen gas from being mixed and exploding.

In the above description, the temperature control means 2
9 to control the temperature of the second cryopanel 16;
It describes the case of releasing hydrogen and oxygen separately,
By sequentially controlling the temperatures of the first cryopanel 15 and the second cryopanel 16 so that the boiling points of the respective substances such as water, nitrogen, oxygen, argon, and hydrogen pass from the lower side, the above-mentioned gases can be selectively removed. Needless to say, it can be exhausted.

<Second Embodiment> FIG. 3 is a cross-sectional view (schematic diagram) of a cryopump equipped with a cryopanel temperature controller according to the present embodiment. This cryopump 3
1 has a single-stage expansion refrigerator 32, and a first cryopanel 34 is attached to an expansion cylinder 33 of the single-stage expansion refrigerator 32.
Is installed. Further, in the first cryopanel 34, two second cryopanels 35 and 36 having a bottomed cylindrical shape are provided such that one is inside the other,
Activated carbon 37 is attached to both surfaces of the inner second cryopanel 35. Hereinafter, the inner second cryopanel 35
Is referred to as a second inner cryopanel, and the outer second cryopanel 36 is referred to as a second outer cryopanel. The first
The cryopanel 34, the second inner cryopanel 35, and the second outer cryopanel 36 are insulated from each other. The mounting structure of the second cryopanels 35 and 36 is not particularly limited.

The second inner cryopanel 35 is provided with a Peltier element 38 and a temperature sensor 39 as temperature adjusting means. Similarly, a Peltier element 40 and a temperature sensor 41 as temperature adjusting means are attached to the second outer cryopanel 36. Then, based on the temperatures of the two second cryopanels 35, 36 detected by the two temperature sensors 39, 41, the Peltier elements 38, 4
Temperature control means 42 for controlling the temperature of 0 is provided. In that case, if the Peltier elements 38 and 40 are wound around the outer periphery of both the second cryopanels 35 and 36 in a belt shape,
Cooling and heating of both the second cryopanels 35 and 36 can be performed in a short time.

The cryopump 31 having the above configuration is
The first cryopanel 34 is cooled to 50K to 80K by the single-stage expansion refrigerator 32, and the water vapor in the vacuum chamber 43 is condensed and exhausted. Further, the temperature control means 42 and the Peltier elements 38, 40 cool both the second cryopanels 35, 36 to 10K to 20K, and the second outer cryopanel 36,
To condense and exhaust nitrogen gas, oxygen gas and argon gas in the vacuum chamber 43. In addition, the activated carbon 37 attached to the second inner cryopanel 35 uses a vacuum chamber 43.
It absorbs hydrogen gas inside and exhausts it.

As shown in FIG. 1, when a two-stage expansion refrigerator 12 is used for the cryopump 11,
Second-stage expansion cylinder 1 cooled to 10K to 20K
The heat sealing material of No. 4 is deteriorated due to too low temperature, and the durability time is limited. However, as in the present embodiment, by using a single-stage expansion refrigerator 32 for the cryopump 31, the heat-resistant temperature of the heat sealing material may be about 40K,
The endurance time can be made about twice as long as when a two-stage expansion refrigerator is used.

In the present embodiment, the second
Two cryopanels 35 and 36 inside and outside
And the first cryopanel 34 and the second
Inner cryopanel 35 and second outer cryopanel 36
Are heated and cooled by independent heating and cooling means. Therefore, by individually controlling the temperatures of the first cryopanel 34, the second inner cryopanel 35, and the second outer cryopanel 36 during the regenerating process, each substance such as water, nitrogen, oxygen, argon, and hydrogen can be selected. It becomes easy to exhaust air.

For example, when the cryopump is stopped, oxygen is condensed on the second outer cryopanel 36 so that the temperature of the second outer cryopanel 36 becomes 80 K or less. After the start of the regeneration process, the temperature of the second inner cryopanel 35 is controlled by the temperature control means 42 so as to be a predetermined temperature of 25K to 80K. By doing so, the hydrogen adsorbed on the activated carbon 37 attached to the second inner cryopanel 35 is released and exhausted, but the oxygen condensed in the second outer cryopanel 36 is not released. As a result, hydrogen gas and oxygen gas are not mixed, and there is no danger of explosion.

After the hydrogen is completely released and exhausted, the temperature of the second outer cryopanel 36 is raised to 80 K or more by the temperature control means 42. Thus, oxygen condensed in the second outer cryopanel 36 is released and exhausted.

In the present embodiment, the second cryopanel is composed of two cryopanels, a second inner cryopanel 35 and a second outer cryopanel 36,
Activated carbon 37 is attached to both surfaces of the inner cryopanel 35. However, as in the first embodiment, the second
The cryopanel may be composed of one cryopanel, and activated carbon may be stuck inside the cryopanel.

[0034]

As is clear from the above, the temperature control device for a cryopanel according to the first aspect of the present invention is a device for controlling the temperature of a second expansion cylinder attached to a second expansion cylinder of a two-stage expansion refrigerator during regeneration processing. Since the cryopanel is heated by the Peltier device, the surface temperature of the Peltier device is higher than the temperature of the second cryopanel only by a predetermined temperature, and the hydrogen gas released from the second cryopanel is dissipated by the Peltier device. It does not explode if you touch it directly.
That is, according to the present invention, the cryopanel can be heated so that the hydrogen gas released during the regeneration processing does not explode.

Further, the temperature control device for a cryopanel according to the second aspect of the present invention uses a single-stage expansion refrigerator as a refrigerator, so that the heat-resistant temperature of the heat sealing material of the expansion cylinder may be about 40K. Therefore, the endurance time can be about twice as long as the case of using the two-stage expansion refrigerator. Further, the second cryopanel is installed in the first cryopanel attached to the expansion cylinder, and the second cryopanel is cooled and heated by the Peltier element. It does not explode if you touch the Peltier device directly.

The second cryopanel in the cryopanel temperature control device according to the third aspect of the present invention may be configured as follows.
Since the Peltier device is attached to each of the second cryopanels, a total of 3
A single cryopanel can separate and condense / adsorb multiple gases. Therefore, during the regeneration process,
/ Separate exhaust of adsorbed substances (especially, separate exhaust of hydrogen and oxygen)
Can be easily done.

The Peltier element in the cryopanel temperature control device according to the fourth aspect of the present invention is mounted by being wound around the outer periphery of the second cryopanel, thereby cooling and heating the second cryopanel. Can be done in a short time.

In the cryopanel temperature controller according to the fifth aspect of the present invention, the temperature of the Peltier element is controlled by a temperature control means, so that the temperature of the second cryopanel is controlled by nitrogen, oxygen, argon, hydrogen or the like. By sequentially controlling the boiling points of the respective substances to pass from below, the respective substances condensed / adsorbed on the second cryopanel can be selectively exhausted.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a cryopump equipped with a cryopanel temperature controller according to the present invention.

FIG. 2 is an explanatory diagram of a Peltier element.

FIG. 3 is a cross-sectional view of a cryopump equipped with a cryopanel temperature controller different from that of FIG. 1;

FIG. 4 is a sectional view of a conventional cryopump.

[Explanation of symbols]

11, 31 ... cryopump, 12 ... two-stage expansion refrigerator, 13 ... first-stage expansion cylinder, 14
... second stage expansion cylinder, 15, 34 ... first cryopanel, 16 ... second cryopanel, 17, 37 ... activated carbon, 21, 22, 38, 40 ... Peltier element, 27, 28, 39, 41 ... temperature Sensor, 29,
42: temperature control means, 32: single-stage expansion refrigerator,
33 ... Expansion cylinder, 35 ... Second inner cryopanel, 36 ... Second outer cryopanel.

Claims (5)

[Claims] The temperature of a cryopanel for adjusting the temperature of a second cryopanel (16) attached to a second-stage expansion cylinder (14) of a two-stage expansion refrigerator (12) in a cryopump (11). An adjusting device, comprising: a peltier element (22) attached to the second cryopanel (16) and heating the second cryopanel (16) during a regeneration process. Adjustment device. 2. A cryopanel temperature controller for adjusting a cryopanel temperature in a cryopump (31) having a single-stage expansion refrigerator (32), wherein the temperature of the single-stage expansion refrigerator (32) is adjusted. A second cryopanel (35, 36) installed in a first cryopanel (34) mounted on the expansion cylinder (33); and a second cryopanel (35, 36) mounted on the second cryopanel (35, 36). A cryopanel temperature controller comprising a Peltier element (38, 40) for cooling and heating the cryopanel (35, 36). 3. The cryopanel temperature adjusting device according to claim 2, wherein there are two second cryopanels (35, 36), and each of the second cryopanel (35, 36) has the Peltier element.
A temperature controller for a cryopanel, wherein (38, 40) is attached. 4. The cryopanel temperature controller according to claim 2, wherein the Peltier element (38, 40) is attached by being wound around the outer periphery of the second cryopanel (35, 36). Characteristic cryopanel temperature controller. 5. The temperature control device for a cryopanel according to claim 1, further comprising temperature control means (29, 42) for controlling the temperature of the Peltier element (22, 38, 40). A cryopanel temperature controller.