JPH07189905A - Regenerating method for cryopump and executing device thereof - Google Patents

Abstract

PURPOSE:To reduce the temperature cycle width at the time of regeneration so as to reduce stress in construction parts by maintaining the inside of a cryopump at less than a saturation steam pressure temperature, when regeneration gas is led in the cryopump and gas molecule's stuck on a cold panel are discharged. CONSTITUTION:When a cryopump 1 is regenerated, firstly a main valve 11 is closed, and communication between a vacuum processing chamber 12 and the cryopump 1 is broken. An electric signal is transmitted from a regeneration control system 5 to a cryopump control system 6, the cold head of the cryopump 1 is stopped, and high vacuum exhaust condition is stopped. And then, a cutoff valve 2 for regeneration gas and a flow rate control valve 3 are opened, and regeneration gas is led in the cryopump 1. Subsequently, after it is detected by a vacuum gage 4 that pressure of regeneration gas is raised, a rough sucking vacuum pump 10 is started by a control system 13 for the rough sucking vacuum pump 10, and also the cutoff valve 8 for rough sucking and a control valve 9 are opened. When the temperature of a cold panel drops to less than the set temperature, regeneration is completed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high vacuum device, and more particularly to a technique effectively applied to a cryopump.

[0002]

2. Description of the Related Art Cryopumps are those which obtain a high vacuum pressure by cooling a cold panel in a cryopump to an extremely low temperature to condense or adsorb gas molecules. There is a limit to the condensation and adsorption of gas molecules in this cold panel, and it is necessary to release the condensed and adsorbed gas molecules to the outside (atmosphere) in order to reuse them after use. This is called regeneration. I'm out.

[0003] Conventionally, a generally used method for regenerating a cryopump is to stop the cold head of the cryopump and then introduce a regenerating gas (generally nitrogen gas) into the cryopump to adjust the pressure in the pump. The gas molecules condensed and adsorbed are released to the outside (atmosphere) by raising the temperature (returning to atmospheric pressure) and raising the temperature of the cold panel cooled to an extremely low temperature.

Then, a series of regenerating work of the cryopump took about 5 to 6 hours.

[0005]

DISCLOSURE OF THE INVENTION The present inventors have found the following problems as a result of examining the above prior art.

In the conventional cryopump regeneration method, after stopping the cold head of the cryopump, a regeneration gas (generally nitrogen gas) is introduced into the cryopump to increase the pressure in the pump (return to atmospheric pressure). At the same time, by raising the temperature of the cold panel cooled to the extremely low temperature, the inside of the cryopump is heated from the extremely low temperature (−250 ° C.) to the room temperature (25 ° C.). Large temperature cycle (275 in temperature range)
℃).

Therefore, there is a problem that the regeneration gas introduction time (vent time) from the vacuum pressure to the atmospheric pressure or the vacuum exhaust time (cool down) from the atmospheric pressure to the vacuum pressure after the regeneration is completed is long. there were.

In order to shorten the cool-down time, there is a method of preliminarily heating and introducing the regenerated gas to a high temperature. In this case, however, a rapid temperature rise occurs and each component in the cryopump is supplied. There was a problem of increasing stress.

An object of the present invention is to provide a technique capable of reducing stress on each component in the cryopump during regeneration.

Another object of the present invention is to provide a technique capable of shortening the restart time of the cryopump.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0012]

Of the inventions disclosed in the present application, a representative one will be briefly described below.
It is as follows.

In a method of regenerating a cryopump in which a regeneration gas is introduced into a cryopump and gas molecules condensed or adsorbed on a cold panel are released to the outside, a saturated vapor pressure temperature in the cryopump is increased when the regeneration gas is introduced. Keep below.

[0014]

According to the above-mentioned means, in the method of regenerating a cryopump in which the regenerating gas is introduced into the cryopump and the gas molecules condensed or adsorbed in the cold panel are released to the outside, the cryogen is introduced when the regenerating gas is introduced. By keeping the inside of the pump below the saturated vapor pressure temperature, the gas condensed or adsorbed on the cold panel inside the cryopump is vaporized at a temperature lower than atmospheric pressure, and the temperature cycle width is reduced, so regeneration is performed. At times, it is possible to reduce the stress on each component in the cryopump.

Further, when the cryopump is regenerated, the inside of the cryopump is evacuated by using a vacuum pump (or a dedicated roughing vacuum evacuation pump) that is usually used for rough evacuation of the vacuum processing chamber. By making the pressure below the vacuum pressure, the vacuum pressure can be maintained inside the cryopump and the amount of gas adsorbed on the inner wall of the cryopump can be reduced, so that the restart time (cool down) of the cryopump can be shortened.

The structure of the present invention will be described below together with embodiments.

In all the drawings for explaining the embodiments, parts having the same function are designated by the same reference numerals, and the repeated description thereof will be omitted.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A cryopump regeneration method according to an embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram for explaining the configuration of the cryopump regeneration system (cryopump and its peripheral devices) of this embodiment.

In FIG. 1, 1 is a cryopump, 2 is a regeneration gas cutoff valve, 3 is a regeneration gas flow control valve, 4
Is a vacuum gauge (for high vacuum, low vacuum), 5 is a control system for regeneration,
6 is a cryopump control system, 7 is a cryopump compressor, 8 is a cryopump roughing shutoff valve, 9
Is a cryopump rough evacuation control valve, 10 is a rough evacuation pump (vacuum exhaust in the processing chamber), 11 is a main valve, 12 is a vacuum processing chamber, 13 is a rough evacuation pump control system, and 14 is an apparatus body control system.

In the cryopump regeneration system of the present embodiment shown in FIG. 1, the cryopump 1 has a vacuum processing chamber 12
Is evacuated to a high vacuum, the regeneration gas shutoff valve 2 is for introducing and shutting off the regeneration gas in the cryopump 1, and the regeneration gas flow control valve 3 controls the introduction amount of the regeneration gas.

The vacuum gauge 4 monitors the pressure inside the cryopump 1, and the regeneration control system 5 opens and closes the cryopump 1 and the regeneration gas shutoff valve 2 when the cryopump 1 is regenerated, and the regeneration gas flow control valve. 3 and the control of the opening / closing amount of the cryopump roughing control valve 9 and the input / output of electric signals for starting and stopping the roughing pump 10 to the roughing pump control system 13 to start and stop the cryopump control system 6 and the like. Is to do.

The cryopump control system 6 activates and deactivates the cold head of the cryopump 1, and the cryopump compressor 7 compresses the helium used for cooling the cold panel inside the cryopump 1 to an extremely low temperature. .

The cryopump rough evacuation shutoff valve 8 is a valve for performing vacuum shutoff or opening between the cryopump 1 and the pump 10 for rough evacuation of the cryopump 1 during or after regeneration. The control valve 9 controls the pressure inside the cryopump during the rough evacuation during the regeneration of the cryopump 1, and the rough pump 10 performs the rough evacuation of the vacuum processing chamber 12 and during the regeneration, the cryopump. Rough evacuation of 1 is performed.

The main valve 11 is a roughing pump control system 1
High vacuum exhaust of 3 and the cryopump 1 is cut off or opened (vacuum exhaust state), the roughing pump control system 13 starts and stops the roughing pump 10, and the apparatus main body control system 14 controls the apparatus main body. And input / output electric signals to / from the reproduction control system 5. The control in each control system described above is performed using a computer or the like.

Next, a method of regenerating a cryopump using the cryopump regenerating system of this embodiment described above will be described. It should be noted that the description will be started assuming that the cryopump has already been started.

First, when regeneration is started, the main valve 11 is fully closed and the vacuum processing chamber 12 and the cryopump 1 are separated (vacuum separation does not mechanically change).
To do.

Then, an electric signal is sent from the regeneration control system 5 to the cryopump control system 6 to stop the cold head inside the cryopump 1 and stop the high vacuum exhaust state. After the stop, the regeneration gas cutoff valve 2 is opened, the regeneration gas flow control valve 3 is gradually opened (in the initial state, it is fully closed), and the regeneration gas is introduced into the cryopump 1.

A regeneration gas was introduced and an arbitrary pressure (vacuum gauge 4
After the vacuum pressure is increased up to the control via the regeneration control system 5, an electric signal is sent from the regeneration control system 5 to activate the roughing pump 10 via the roughing pump control system 13.

Thereafter, the cryopump rough evacuation shut-off valve 8 is fully opened, and the cryopump rough evacuation control valve 9 is gradually opened (initial state is fully closed). The vacuum pressure value of the vacuum gauge 4 is adjusted to an arbitrary pressure. The opening degree of the cryopump roughing control valve 9 and the regeneration gas flow rate control valve 3 is controlled by monitoring through the regeneration control system 5.

After the set time (set by the regeneration control system 5) has elapsed, the regeneration gas cutoff valve 2 and the regeneration gas flow control valve 3 are fully closed. The work up to this point completes the release of the condensed or adsorbed gas.

Next, the cryopump rough evacuation control valve 9
Is fully opened to start the rough evacuation of the cryopump 1. After that, after the inside of the cryopump 1 reaches an arbitrary set vacuum pressure and pressure increase value, the cryopump roughing shutoff valve 8 and the cryopump roughing control valve 9 are fully closed, and the cryocontrol from the regeneration control system 5 is performed. An electric signal is sent to the pump control system 6 to start (restart) the cold head of the cryopump 1. Then, when the temperature of the cold panel of the cryopump 1 becomes below the set temperature, the cryopump regeneration operation is completed.

Finally, the main valve 11 is opened and a series of regeneration work is completed.

In the present embodiment, the pump for roughing the inside of the cryopump is commonly used as the pump for roughing the inside of the vacuum processing chamber, but a pump for roughing the inside of the cryopump is newly provided. , May be controlled independently.

Therefore, in the method of regenerating a cryopump in which a regenerating gas is introduced into the cryopump and the gas molecules condensed or adsorbed in the cold panel are released to the outside, a saturated vapor in the cryopump is introduced when the regenerating gas is introduced. By keeping the temperature below the pressure temperature, the gas condensed or adsorbed on the cold panel in the cryopump is vaporized at a temperature lower than the atmospheric pressure, and the temperature cycle width is reduced. It is possible to reduce stress on each component.

When the cryopump is regenerated, the inside of the cryopump is evacuated by using a vacuum pump (or a dedicated roughing vacuum evacuation pump) which is usually used for rough evacuation of the vacuum processing chamber. By making the pressure below the vacuum pressure, the vacuum pressure can be maintained inside the cryopump and the amount of gas adsorbed on the inner wall of the cryopump can be reduced, so that the restart time (cool down) of the cryopump can be shortened.

Further, by utilizing a rough evacuation pump (or a dedicated rough evacuation pump) for the rough evacuation in the vacuum processing chamber, regeneration is carried out at an arbitrary saturated vapor pressure temperature or lower while maintaining the set vacuum pressure. , Longer life of internal components by reducing temperature cycle in the cryopump, improvement of operating time by shortening restart time after regeneration, prevention of contamination in the cryopump by holding vacuum, and prevention of vacuum leak. Will also be possible.

The inventions made by the present inventors are as follows.
Although the present invention has been specifically described based on the above-mentioned embodiments, the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without departing from the scope of the invention.

[0039]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.

In a method of regenerating a cryopump in which a regeneration gas is introduced into a cryopump and gas molecules condensed or adsorbed on a cold panel are released to the outside, a saturated vapor pressure temperature in the cryopump is increased when the regeneration gas is introduced. By holding below, the gas condensed or adsorbed on the cold panel in the cryopump is vaporized at a temperature lower than atmospheric pressure, and the temperature cycle width is reduced,
It is possible to reduce the stress on each component in the cryopump during regeneration.

When the cryopump is regenerated, the inside of the cryopump is evacuated by using a vacuum pump (or a dedicated roughing vacuum evacuation pump) normally used for rough evacuation of the vacuum processing chamber. Since it is possible to maintain the vacuum pressure inside the cryopump by making it below the vacuum pressure of
Since the amount of gas adsorbed to the inner wall of the cryopump can be reduced, the restart time (cooldown) of the cryopump can be shortened.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the configuration of a cryopump regeneration system that is an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cryo pump, 2 ... Regeneration gas cutoff valve, 3 ... Regeneration gas flow control valve, 4 ... Vacuum gauge (for high vacuum, low vacuum), 5 ... Regeneration control system, 6 ... Cryo pump control system, 7 ... Cryopump compressor, 8 ... Cryopump roughing shutoff valve, 9 ... Cryopump roughing control valve, 10 ... Roughing pump (vacuum exhaust of processing chamber), 11 ... Main valve, 12 ... Vacuum processing chamber, 13 ... Coarse Pull pump control system, 14 ... Device body control system.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Koichi Koyanagi, 3-3 Fujibashi, Ome, Tokyo 2-3 Hitachi Hitachi Electronics Co., Ltd. (72) Inventor Jiro Sakaguchi 3-3, Fujibashi, Ome, Tokyo 2 Hitachi Inside Tokyo Electronics Co., Ltd. (72) Inventor Tadao Sakamoto 3-3 Fujibashi, Ome City, Tokyo 2 Inside Hitachi Tokyo Electronics Co., Ltd.

Claims (2)

[Claims] 1. A method of regenerating a cryopump in which a regenerating gas is introduced into a cryopump and the gas molecules condensed or adsorbed in a cold panel are released to the outside. When the regenerating gas is introduced, saturated vapor in the cryopump is introduced. A method for regenerating a cryopump, which is characterized in that the cryopump is maintained at a pressure temperature or lower. 2. A pump casing having an intake hole, a cold panel provided inside the casing for cooling to an extremely low temperature to condense and adsorb gas molecules, a control means for controlling the cold panel, and a pump regeneration unit. In a cryopump consisting of a regenerated gas introduction pipe for introducing a regenerated gas for removing gas molecules adsorbed on the cold panel and a regenerated gas discharge pipe for discharging the regenerated gas, a vacuum exhaust is performed inside the pump casing when the pump is regenerated. A cryopump provided with a vacuum evacuation means and a control means therefor.