Method for regenerating cryopump

Abstract

The present invention provides a method for regenerating a cryopump, the cryopump comprising: a refrigerator provided with a first stage part and a second stage part and cooling the first stage part and the second stage part by using a high-pressure refrigerant; a cryopanel including a first-stage panel cooled by the first-stage stage part and a second-stage panel cooled by the second-stage stage part; a cryopump container surrounding the cryopanel and including a radiation shield surrounding the first stage portion; the first heater is arranged on the first-stage panel; and a second heater provided on the second-stage panel, the method comprising: a temperature raising step of turning on (On) the first heater to raise the temperature of the radiation shield and the first-stage panel; a roughing step of controlling a roughing valve for adjusting the vacuum in the cryopump container in a state in which the cryopump container maintains a pressure at which the ice in a solid state can sublimate to steam in a gaseous state; a purge step of supplying a purge gas into the cryopump container; and a cooling step of reducing the temperature of the first-stage panel and the second-stage panel.

Description

Technical Field

[0001] The invention relates to a regeneration method for a cryogenic pump. Background Art

[0002] Ultra-low temperature cooling is widely used in various industrial fields such as semiconductor manufacturing and testing. Here, ultra-low temperature can refer to temperatures below -200 degrees. The cooling process used to obtain ultra-low temperatures generally includes a compressor, a condenser, an expander, and an evaporator. The refrigerant evaporates in the evaporator to create an ultra-low temperature environment.

[0003] Regarding this technology of constructing an ultra-low temperature environment, Korean Patent Publication No. 2020-0079062, which is a prior art, discloses an ultra-low temperature refrigerator.

[0004] In order to create an ultra-low temperature environment, GM (Gifford-McMahon) refrigerators are mainly used as high vacuum cryopump refrigerators. Cryopumps are capture pumps and cannot pump more than a specified capacity. After being used in the cooling process, they must be regenerated periodically.

[0005] The regeneration process is a process of desorbing and evaporating the water and gas adsorbed, condensed, and solidified on the cryopanel of the cryopump to restore the suction capacity. Figure 1 A regeneration process performed in a conventional cryopump will be described.

[0006] Figure 1 2 is a diagram showing a regeneration process performed in a conventional cryopump. Figure 1 The regeneration process generally consists of a cryopump preheating (110, warm up) process, a purge (120, purge) process, a roughing (130, roughing) process, and a cool down (140, cool down) process. As the regeneration process is performed, the temperature 100 of the first stage and the temperature 101 of the second stage of the cryopump change. As the above processes are performed in sequence, the regeneration process (150) is completed.

[0007] In the case of an 8-inch sputtering equipment generally used in the production of semiconductor foundry products, there are 6 chambers (4 process chambers, 1 transfer chamber, and 1 buffer chamber), and a cryopump is installed in each chamber. The production process performed in this sputtering equipment is to repeatedly perform a photolithography process, an etching process, an ion implantation process, and a vapor deposition process to generate countless semiconductor circuits on the wafer.

[0008] Here, the sputtering equipment uses a wet scrubbing process to separate or capture tiny particles in the dust gas by dispersing the cleaning liquid or dust gas in the etching process to generate liquid crystals, liquid films, bubbles, etc. The wafer is rotated at a very high speed, and water is sprayed on the surface of the wafer for cleaning, while it is rotated at a very high speed and dried by centrifugal force.

[0009] After that, the metallization process of connecting the metal wires along the semiconductor circuit pattern is carried out. However, when the atmosphere of the buffer chamber of the sputtering equipment is 300 degrees, a large amount of water components remaining in the previous process evaporate and accumulate on the cold head to form ice. Here, when the regeneration process is carried out, the ice will accumulate at the bottom between the tank body and the pump body, and the ROR (Rate of Rise, leak test) failure will be caused by the generation of H2O inside the cryopump, resulting in a long regeneration time of about 8 hours or more.

[0010] The reason for the generation of this H2O is that it is captured in the low temperature stage in the state of ice in the process before flowing into the buffer chamber. When the regeneration process is carried out, it changes into water as the surrounding temperature and pressure increase in the purge process and accumulates inside the low temperature chamber. After that, when the pump is running, it is vaporized as the chamber pressure decreases, and the pressure state deteriorates, resulting in ROR failure (Fail), which becomes the reason for the prolonged regeneration time. Summary of the invention

[0011] Technical issues

[0012] The present invention provides the following method for regenerating a cryopump: turning on a first heater to raise the temperature of a radiation shield and a primary panel, and controlling a roughing valve for regulating the vacuum in a cryopump container under a pressure state in which ice in a solid state can be sublimated into steam in a gaseous state.

[0013] The present invention provides a cryopump regeneration method for supplying a purge gas into a cryopump housing to reduce the temperatures of a primary panel and a secondary panel.

[0014] However, the technical problems to be solved by this embodiment are not limited to the above-mentioned technical problems, and there may be other technical problems.

[0015] Technical Solution

[0016] As a means for solving the above-mentioned technical problems, one embodiment of the present invention can provide a regeneration method for a cryopump, which includes: a refrigerator, having a first stage and a second stage, using a high-pressure refrigerant to cool the first stage and the second stage; a cryopanel, including a first panel cooled by the first stage and a second panel cooled by the second stage; a cryopump container surrounding the cryopanel, including a radiation shield surrounding the first stage; a first heater, arranged on the first panel; and a second heater, arranged on the second panel, wherein the regeneration method for the cryopump includes: a heating process step, turning on the first heater to heat the radiation shield and the first panel; a rough pumping process step, controlling a rough pumping valve for adjusting the vacuum in the cryopump container under a state where the cryopump container maintains a pressure at which ice in a solid state can sublime into steam in a gaseous state; a purging process step, supplying a purging gas into the cryopump container; and a cooling process step, reducing the temperature of the first panel and the second panel.

[0017] According to one embodiment, before the temperature increasing step, a step of stopping the operation of the refrigerator may be further included.

[0018] According to one embodiment, the pressure at which the solid ice can sublime into the gaseous steam can be 10 -2 Up to 10 -3 torr.

[0019] According to an embodiment, the purging process may include a step of opening the roughing valve to maintain the pressure in the cryopump container at a pressure lower than a pressure at which solid ice can sublime into gaseous steam.

[0020] According to an embodiment, the rough pumping process may include: after opening the rough pumping valve, when the temperature of the primary panel reaches a preset temperature, closing the rough pumping valve.

[0021] According to one embodiment, the purging process may include: maintaining the temperature of the primary panel at a set temperature using the first heater; and maintaining the temperature of the secondary panel at a set temperature using the second heater.

[0022] The above-mentioned means for solving the problems are merely illustrative and should not be construed as limiting the present invention. In addition to the above-mentioned illustrative embodiments, there may be additional embodiments described in the drawings and the detailed description of the invention.

[0023] Effects of the Invention

[0024] According to any one of the above-mentioned means for solving the problems of the present invention, it is possible to provide a cryopump which can directly sublime solid ice into gaseous steam by turning on the first heater to increase the temperature of the radiation shield and the primary panel.

[0025] The following cryopump can be provided: a technology for adjusting the temperature and pressure inside the cryopump by controlling a roughing valve for adjusting the vacuum in the cryopump container under a pressure state in which ice in a solid state maintained in the cryopump container can sublime into steam in a gaseous state, thereby maintaining a management environment so that it can maintain a region in which water sublimates directly from a solid into a gas during the state change of water.

[0026] A cryopump can be provided in which the factor causing the generation of H 2 O as liquid accumulated at the bottom of a radiation shield and a primary panel is removed, thereby shortening the regeneration time required for the cryopump. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a diagram showing a regeneration process performed in a conventional cryopump.

[0028] Figure 2 This is an illustrative diagram showing a cryopump according to an embodiment of the present invention.

[0029] Figure 3 This is a sequence diagram of a regeneration method performed in a cryopump according to an embodiment of the present invention.

[0030] Figure 4 This is an exemplary diagram showing the pressure at which solid ice can sublime into gaseous steam according to an embodiment of the present invention. DETAILED DESCRIPTION

[0031] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. However, the present invention can be implemented in various different ways and is not limited to the embodiments described herein. Furthermore, in order to clearly illustrate the present invention, parts not related to the description are omitted in the accompanying drawings, and similar parts are marked with similar reference numerals throughout the specification.

[0032] Throughout the specification, when a part is described as being "connected" to another part, this includes not only the case of "direct connection" but also the case of "electrical connection" with other elements interposed therebetween. In addition, when a part is described as "including" a certain constituent element, unless otherwise specifically described, it means that other constituent elements are not excluded and other constituent elements can be further included, and it should be understood that the existence or additional possibility of one or more other features or numbers, steps, actions, constituent elements, partial components or combinations thereof is not excluded in advance.

[0033] In this specification, "unit" includes a unit implemented by hardware, a unit implemented by software, and a unit implemented by both. In addition, one unit may be implemented by two or more hardware, or two or more units may be implemented by one unit.

[0034] In this specification, a part of the actions or functions performed by a terminal or device can also be performed in a server connected to the terminal or device instead. Similarly, a part of the actions or functions performed by a server can also be performed in a terminal or device connected to the server.

[0035] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0036] Figure 2 : is an exemplary diagram showing a cryopump according to an embodiment of the present invention. Figure 2 The cryopump 200 may include a refrigerator 210, a primary stage 211, a secondary stage 212, a primary panel 220, a secondary panel 221, a cryopump container 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 invention may be a GM (Gifford-McMahon) refrigerator having the primary stage 211 and the secondary stage 212.

[0037] The refrigerator 210 may include a primary stage 211 and a secondary stage 212 cooled to a lower temperature than the primary stage 211. Here, the primary stage 211 and the secondary stage 212 may create an ultra-low temperature environment by utilizing the cooling principle that the displacer moves back and forth in the chamber to expand the internal He gas.

[0038] The cryopump container 230 can surround the cryopanel. Here, the cryopanel can include a primary panel 220 and a secondary panel 221. The primary panel 220 includes a primary array and a partition, the primary array is directly cooled by the primary stage 211, the partition is indirectly cooled by the primary stage 211, and the secondary panel 221 includes a secondary array and can be cooled by the secondary stage 212. In the following, it is assumed that the primary panel 220 is a partition for explanation.

[0039] The cryopump housing 230 can include a radiation shield 231. The radiation shield 231 can surround the primary stage 211, thereby protecting the cryopump 200 from radiant heat at room temperature.

[0040] The first heater 240 is provided on the primary stage 211 and can increase the temperature of the primary stage 211 .

[0041] The second heater 241 is provided on the secondary stage 212 and can increase the temperature of the secondary stage 212 .

[0042] The roughing valve 250 can adjust the vacuum in the cryopump housing 230 .

[0043] Figure 3 This is a sequence diagram of a regeneration method performed in a cryopump according to an embodiment of the present invention. Figure 3 The regeneration method of the cryopump 200 shown in the cryopump 200 includes: Figure 2 Therefore, even if the following contents are omitted, they are also applicable to the embodiments based on Figure 2 The illustrated embodiment shows a method for regenerating the cryopump 200 performed in the cryopump 200 .

[0044] In step S310, the cryopump 200 can turn on the first heater 240 to increase the temperature of the radiation shield 231 and the primary panel 220. Here, before executing step S310, the cryopump 200 can also include a step of stopping the operation of the refrigerator 210.

[0045] In step S320, the cryopump 200 can control the roughing valve 250 for adjusting the vacuum in the cryopump container 230 while maintaining the pressure at which the solid ice can be sublimated into the gaseous steam. Here, the pressure at which the solid ice can be sublimated into the gaseous steam can be 10 -2 Up to 10 -3 torr.

[0046] The method may include the steps of opening the roughing valve 250 by the cryopump 200 to maintain the pressure in the cryopump container 230 below the pressure at which ice in a solid state can sublime into steam in a gaseous state, and closing the roughing valve 250 after the roughing valve 250 is opened and when the temperature of the primary panel 220 reaches a preset temperature. Here, the preset temperature may be 250K to 300K. Figure 4 The pressure at which solid ice can sublime into gaseous steam is described.

[0047] Figure 4 : is an example diagram showing the pressure at which solid ice can sublime into gaseous steam according to an embodiment of the present invention. Figure 4 , regarding the water phase diagram 400 , the state of water can be represented by x-axis: temperature 410 and y-axis: pressure 420 .

[0048] Reference Figure 4 , at temperatures below -20 degrees to 0 degrees and pressures of 10 -3 Up to 10 3torr can be in a solid state (ice), and can be in a solid state (ice) at a temperature of 0 to 120 and a pressure of 10 -2 Up to 10 3 torr, it can be in liquid state (water), at a temperature of -20 degrees to 120 degrees and a pressure of 10 -3 When the pressure reaches 10 torr, it can be in gaseous state (steam).

[0049] Here, the pressure at which the solid ice can sublime into the gaseous steam can be 10 -2 Up to 10 -3 torr(430).

[0050] That is, in the present invention, while maintaining the pressure at 10 -2 When the following regeneration process is performed simultaneously, ice in a solid state at a temperature below 0 degrees is sublimated directly into steam in a gaseous state without passing through a liquid state, thereby making it easy to remove moisture.

[0051] In addition, the internal temperature and pressure of the cryopump 200 are adjusted to manage the environment so that the water can be maintained in a region where it sublimates directly from a solid state to a gas state during the state change process, thereby eliminating the cause of the generation of liquid H 2 O and reducing the regeneration time.

[0052] Back again Figure 3 In step S330, the cryopump 200 can supply a purge gas into the cryopump housing 230. Here, the purge gas may be nitrogen (N2) gas.

[0053] In step S330 , the cryopump 200 may include a step of maintaining the temperature of the primary panel 220 at a set temperature using the first heater 240 and a step of maintaining the temperature of the secondary panel 221 at a set temperature using the second heater 241 .

[0054] In step S340 , the cryopump 200 can reduce the temperatures of the primary panel 220 and the secondary panel 221 .

[0055] According to the present invention, even when the cryopump 200 is used in a sputtering device, the generation of water in the regeneration process can be minimized, and thus the regeneration speed can be increased.

[0056] In the above description, steps S310 to S340 can be further divided into more steps or combined into fewer steps according to the embodiment of the present invention. In addition, some steps can be omitted as needed, and the order of the steps can be changed.

[0057] pass Figures 2 to 4The cryopump regeneration method described above and executed in the cryopump may also be implemented in the form of a computer program stored in a medium and executed by a computer or a recording medium containing instructions executable by a computer. Figures 2 to 4 The cryopump regeneration method described above and executed in the cryopump may also be realized in the form of a computer program stored in a medium and executed by a computer.

[0058] Computer readable media can be any available media that can be accessed by a computer, including all volatile and nonvolatile media, separable and non-separable media. In addition, computer readable media can include computer storage media. Computer storage media includes all volatile and nonvolatile, separable and non-separable media implemented by any method or technology for storing information such as computer readable commands, data structures, program modules or other data.

[0059] It should be understood that the above description of the present invention is for illustration, and those skilled in the art can easily transform into other specific modes without changing the technical ideas or essential features of the present invention. Therefore, it should be understood that the above-described embodiments are illustrative and non-limiting in all aspects. For example, each component described in a single form can also be implemented in a dispersed manner, and the components described in a dispersed form can also be implemented in a combined manner.

[0060] The scope of the present invention is indicated by the claims rather than the detailed description above, and it should be construed that all changes and modifications derived from the meaning and scope of the claims and their equivalents are included in the scope of the present invention.

Claims

1. A method for regenerating a cryopump, the cryopump comprising: A refrigerator, comprising a primary stage and a secondary stage, using a high-pressure refrigerant to cool the primary stage and the secondary stage; a cryopanel, comprising a primary panel cooled by the primary stage and a secondary panel cooled by the secondary stage; a cryopump container surrounding the cryopanel, including a radiation shield surrounding the primary stage; a first heater, arranged on the primary panel; and a second heater, disposed on the secondary panel, wherein the regeneration method of the cryopump comprises: A heating process step of turning on the first heater to increase the temperature of the radiation shield and the primary panel; A roughing process step of controlling a roughing valve for adjusting the vacuum in the cryopump container while maintaining a pressure at which ice in a solid state can sublime into steam in a gaseous state in the cryopump container; a purge process step of supplying a purge gas into the cryopump container; and The cooling process step reduces the temperature of the primary panel and the secondary panel.

2. The cryopump regeneration method according to claim 1, wherein: Before the above-mentioned temperature increasing process step, the method also includes a step of stopping the operation of the above-mentioned refrigerator.

3. The cryopump regeneration method according to claim 1, wherein: The pressure at which the solid ice can sublime into gaseous steam is 10 -2 Up to 10 -3 torr.

4. The cryopump regeneration method according to claim 3, wherein: The above-mentioned rough extraction process steps include: The step of opening the roughing valve to maintain the pressure in the cryopump housing at a pressure lower than the pressure at which ice in a solid state can sublime into steam in a gaseous state.

5. The cryopump regeneration method according to claim 4, wherein: The above-mentioned rough extraction process steps include: After the roughing valve is opened, when the temperature of the first-level panel reaches a preset temperature, the roughing valve is closed.

6. The cryopump regeneration method according to claim 5, wherein: The above preset temperature is 250K to 300K.

7. The cryopump regeneration method according to claim 1, wherein: The above-mentioned purging process steps include: The step of maintaining the temperature of the primary panel at a set temperature by using the first heater; and The step of maintaining the temperature of the secondary panel at a set temperature by using the second heater.

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