METHOD FOR REGENERATING CRYOPUMP

Abstract

A method for regenerating a cryopump that includes a cooler including a first stage part and a second stage part, and configured to cool the first stage part and the second stage part with a high pressure refrigerant; a cryopanel including a first panel which is cooled by the first stage part and a second panel which is cooled by the second stage part; a cryopump vessel configured to surround the cryopanel and including a radiation shield that surrounds the first stage part; a first heater provided in the first panel; and a second heater provided in the second panel, the method comprising a temperature increasing process of increasing temperatures of the radiation shield and the first panel by turning on the first heater, a roughing process of controlling a roughing valve configured to regulate vacuum within the cryopump vessel in a state where the cryopump vessel is kept at a pressure at which solid state ice can sublimate into gas state vapor, a purging process of supplying a purge gas into the cryopump vessel, and a cool-down process of lowering the temperatures of the first panel and the second panel.

Claims

1. A method for regenerating a cryopump that includes a cooler including a first stage part and a second stage part, and configured to cool the first stage part and the second stage part with a high pressure refrigerant; a cryopanel including a first panel which is cooled by the first stage part and a second panel which is cooled by the second stage part; a cryopump vessel configured to surround the cryopanel and including a radiation shield that surrounds the first stage part; a first heater provided in the first panel; and a second heater provided in the second panel, the method comprising: a temperature increasing process of increasing temperatures of the radiation shield and the first panel by turning on the first heater; a roughing process of controlling a roughing valve configured to regulate vacuum within the cryopump vessel in a state where the cryopump vessel is kept at a pressure at which solid state ice can sublimate into gas state vapor; a purging process of supplying a purge gas into the cryopump vessel; and a cool-down process of lowering the temperatures of the first panel and the second panel.

2. The method for regenerating a cryopump of claim 1, further comprising: before the temperature increasing process, stopping an operation of the cooler.

3. The method for regenerating a cryopump of claim 1, wherein the pressure at which solid state ice can sublimate into gas state vapor ranges from 10.sup.2 torr to 10.sup.3 torr.

4. The method for regenerating a cryopump of claim 3, wherein the roughing process includes: maintaining a pressure inside the cryopump vessel to be equal to or lower than the pressure at which solid state ice can sublimate into gas state vapor by opening the roughing valve.

5. The method for regenerating a cryopump of claim 4, wherein the roughing process includes: closing the roughing valve when the temperature of the first panel reaches a predetermined temperature after the roughing valve has been opened.

6. The method for regenerating a cryopump of claim 5, wherein the predetermined temperature ranges from 250K to 300K.

7. The method for regenerating a cryopump of claim 1, wherein the purging process includes: maintaining the temperature of the first panel at a preset temperature by using the first heater; and maintaining the temperature of the second panel at a preset temperature by using the second heater.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG. 1 illustrates a regeneration process performed in a conventional cryopump.

[0025] FIG. 2 is an example of a cryopump according to an embodiment of the present disclosure.

[0026] FIG. 3 is a flowchart of a regeneration method performed in a cryopump according to an embodiment of the present disclosure.

[0027] FIG. 4 is an example of showing pressures at which solid state ice can sublimate into gas state vapor according to an embodiment of the present disclosure.

BEST MODE FOR CARRYING OUT THE INVENTION

[0028] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present disclosure pertains can easily implement it. However, the present disclosure may be embodied in various forms and is not limited to the embodiments described herein. Furthermore, parts unrelated to the explanation have been omitted from the drawings to clearly describe the present disclosure, and similar reference numerals are used for similar parts throughout the specification.

[0029] Throughout this specification, when a certain part is described as being connected to another part, this includes not only cases where they are directly connected but also cases where they are electrically connected with other elements interposed therebetween. Additionally, when a certain part is described as including a certain component, unless specifically stated otherwise, it does not exclude other components but may further include additional components. It should be understood that this does not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0030] In this specification, the term unit refers to a unit implemented by hardware, a unit implemented by software, or a unit implemented using both. Moreover, one unit may be realized using two or more pieces of hardware, and two or more units may be realized by a single piece of hardware.

[0031] In this specification, some of the operations or functions described as being performed by a terminal or device may instead be performed by a server connected to the terminal or device. Similarly, some of the operations or functions described as being performed by a server may instead be performed by a terminal or device connected to the server.

[0032] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.

[0033] FIG. 2 is an example of a cryopump according to an embodiment of the present disclosure. Referring to FIG. 2, a cryopump 200 may include a cooler 210, a first stage part 211, a second stage part 212, a first panel 220, a second panel 221, a cryopump vessel 230, a radiation shield 231, a first heater 240, a second heater 241, and a roughing valve 250. The cryopump 200 according to an embodiment of the present disclosure may be a GM (Gifford-McMahon) cooler includes the first stage part 211 and the second stage part 212.

[0034] The cooler 210 may include the first stage part 211 and the second stage part 212 which is cooled to a lower temperature than the first stage part 211. Herein, the first stage part 211 and the second stage part 212 may create a cryogenic environment by using a cooling principle that allows a displacer to reciprocate within a cylinder and expand a helium (He) gas inside the cylinder.

[0035] The cryopump vessel 230 may surround a cryopanel. Herein, the cryopanel may include the first panel 220 and the second panel 221. The first panel 220 may include a first array and a baffle, and the first array may be cooled directly by the first stage part 211 and the baffle may be cooled indirectly by the first stage part 211. Also, the second panel 122 may include a second array and may be cooled by the second stage part 212. Hereafter, it is assumed that the first panel 220 is a baffle.

[0036] The cryopump vessel 230 may include the radiation shield 231. The radiation shield 231 may protect the cryopump 200 against radiant heat at room temperature by surrounding the first stage part 211. The first heater 240 may be provided in the first stage part 211 and may increase a temperature of the first stage part 211. The second heater 241 may be provided in the second stage part 212 and may increase a temperature of the second stage part 212.

[0037] The roughing valve 250 is configured to regulate vacuum within the cryopump vessel 230.

[0038] FIG. 3 is a flowchart of a regeneration method performed in a cryopump according to an embodiment of the present disclosure. The method for regenerating the cryopump 200 performed in the cryopump 200 illustrated in FIG. 3 includes the processes time-sequentially performed according to the embodiment illustrated in FIG. 2. Therefore, the descriptions of the processes may also be applied to the method for regenerating the cryopump 200 performed in the cryopump 200 according to the embodiment illustrated in FIG. 2 even though they are omitted hereinafter.

[0039] In a process S310, the cryopump 200 may increase temperatures of the radiation shield 231 and the first panel 220 by turning on the first heater 240. Herein, the cryopump 200 may further perform a process of stopping an operation of the cooler 210 before the process S310.

[0040] In a process S320, the cryopump 200 may control the roughing valve 250 configured to regulate vacuum within the cryopump vessel 230 in a state where the cryopump vessel 230 is kept at a pressure at which solid state ice can sublimate into gas state vapor. Herein, the pressure at which solid state ice can sublimate into gas state vapor may range from 10.sup.2 torr to 10.sup.3 torr.

[0041] The cryopump 200 may include a process of opening the roughing valve 250 to maintain the pressure inside the cryopump vessel 230 to be equal to or lower than the pressure at which solid state ice can sublimate into gas state vapor, and a process of closing the roughing valve 250 when a temperature of the first panel 220 reaches a predetermined temperature after the roughing valve 250 has been opened. Herein, the predetermined temperature may range from 250K to 300K. The pressure at which solid state ice can sublimate into gas state vapor will be described briefly with reference to FIG. 4.

[0042] FIG. 4 is an example of showing pressures at which solid state ice can sublimate into gas state vapor according to an embodiment of the present disclosure. Referring to FIG. 4, a water phase diagram 400 represents the states of water along an X-axis: temperature 410 and a Y-axis: pressure 420.

[0043] Referring to FIG. 4, water exists as a solid (ice) when the temperature is between 20 C. and 0 C. and the pressure is between 10.sup.3 torr and 10.sup.3 torr, as a liquid (water) when the temperature is between 0 C. and 120 C. and the pressure is between 10.sup.2 torr and 10.sup.3 torr, and as a gas (vapor) when the temperature is between 20 C. and 120 C. and the pressure is between 10.sup.3 torr and 10 torr.

[0044] Herein, the pressure at which solid state ice can sublimate into gas state vapor may correspond to the intersection between the solid and gas lines in a range of from 10.sup.2 torr to 10.sup.3 torr 430.

[0045] That is, according to the present disclosure, when the regeneration process is performed at a maintained pressure of 10.sup.2 torr or lower, it is possible to easily remove water by allowing solid state ice to sublimate directly into gas state vapor at a temperature of 0 C. or lower without passing through the liquid state.

[0046] Further, it is possible to eliminate the factors that cause the generation of liquid H.sub.2O and reduce the regeneration time by regulating the temperature and pressure inside the cryopump 200 to maintain and manage the environment where water undergoes direct sublimation from solid into gas during phase transition.

[0047] Referring back to FIG. 3, in a process S330, the cryopump 200 may supply a purge gas into the cryopump vessel 230. The purge gas may be a nitrogen (N.sub.2) gas. In the process S330, the cryopump 200 may include a process of maintaining the temperature of the first panel 220 at a preset temperature by using the first heater 240 and a process of maintaining the temperature of the second panel 221 at a preset temperature by using the second heater 241.

[0048] In a process S340, the cryopump 200 may lower the temperatures of the first panel 220 and the second panel 221.

[0049] According to the present disclosure, even when the cryopump 200 is used in a sputtering machine, it can minimize the generation of water during the regeneration process and thus improve the regeneration speed.

[0050] In the descriptions above, the processes S310 to S340 may be divided into additional processes or combined into fewer processes depending on an embodiment. In addition, some of the processes may be omitted and the sequence of the processes may be changed if necessary.

[0051] The method for regenerating the cryopump performed in the cryopump as described above with reference to FIG. 2 to FIG. 4 can be implemented as a computer program stored in a medium to be executed by a computer or a storage medium including instructions executable by a computer. The method for regenerating the cryopump performed in the cryopump as described above with reference to FIG. 2 to FIG. 4 can be implemented as a computer program stored in a medium to be executed by a computer.

[0052] A computer-readable medium may be any available medium accessible by a computer and includes both volatile and non-volatile media, as well as removable and non-removable media. Additionally, the computer-readable medium may include computer storage media. Computer storage media encompass both volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information such as computer-readable instructions, data structures, program modules, or other data.

[0053] The foregoing description of the present disclosure is provided by way of example, and those skilled in the art to which the present disclosure pertains will understand that various modifications can be made in other specific forms without departing from the technical spirit or essential characteristics of the present disclosure. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as being implemented in a singular form may also be implemented in a distributed manner, and likewise, components described as being distributed may also be implemented in a combined form.

[0054] The scope of the present disclosure is indicated by the claims described below rather than the detailed description above, and it should be interpreted that all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts are included within the scope of the present disclosure.