Patent Application
20250230805
The present disclosure relates to a method for regenerating a cryopump.
Cryogenic cooling is widely used in various industrial fields such as semiconductor manufacturing and testing. Herein, cryogenic refer to temperatures below −200° C. A cooling process to achieve cryogenic typically includes a compressor, a condenser, an expander, and an evaporator, wherein refrigerant evaporates in the evaporator to create a cryogenic environment.
In relation to technology for creating a cryogenic environment, prior art Korean Patent Publication No. 2020-0079062 discloses an ultra-cold cooler.
To create a cryogenic environment, GM (Gifford-McMahon) coolers, which are coolers for high-vacuum cryopumps, are mainly used. A cryopump is a capture pump, and since it is difficult to pump beyond a certain capacity, a regeneration process must be periodically executed after use in a cooling process.
The regeneration process refers to a process that restores the pumping capability of the cryopump by desorbing and evaporating water and gases that have been adsorbed, condensed, or solidified on a cryopanel of the cryopump. A regeneration process performed in a conventional cryopump will be described briefly with reference to
In general, an 8-inch sputtering machine used for semiconductor foundry production is equipped with six chambers (four process chambers, one transfer chamber, and one buffer chamber), and one cryopump is provided in each chamber. The production process performed in the sputtering machine involves repeated execution of photolithography process, etching process, ion implantation process and deposition processes process, and thus fabricates numerous semiconductor circuits on a wafer.
Herein, the sputtering machine performs a wet scrubber process for separating or collecting fine particles in a dirty gas by utilizing liquid crystals, liquid films, bubbles, and similar phenomena, which are generated by dispersing a cleaning solution or dirty gas during etching process, while simultaneously spraying water onto the surface of the wafer to clean the wafer and rotating the wafer at high speed to dry the wafer through centrifugal force.
Subsequently, the sputtering machine performs a metal process for connecting metal lines along a semiconductor circuit pattern, but when the buffer chamber of the sputtering machine reaches an ambient temperature of 300° C., a large amount of water remaining from the previous process evaporates, accumulates on a cold head, forming ice. Herein, when the regeneration process is performed, ice accumulates at the bottom between a can and a pump body, and the generation of H2O inside the cryopump leads to a rate of rise (ROR) failure, thereby requiring a long regeneration time of about eight hours or more.
Herein, H2O is generated when moisture, which has been collected in the form of ice in a cryogenic stage during a process before the buffer chamber is loaded, turns to water and accumulates inside a cryogenic chamber as the ambient temperature and pressure increases through the purge process during the regeneration process. Subsequently, during a pumping process, the water vaporizes as the chamber pressure decreases, which leads to degraded pressure conditions, results in the ROR failure and thus increases the regeneration time.
It is conceived to provide a method for regenerating a cryopump, including increasing temperatures of a radiation shield and a first panel by turning on a first heater, and controlling a roughing valve configured to regulate vacuum within a 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.
It is conceived to provide a method for regenerating a cryopump, including supplying a purge gas into a cryopump vessel, and lowering temperatures of a first panel and a second panel.
However, the problems intended to be achieved by the present embodiment are not limited to the aforementioned technical objectives, and other problems intended to be solved may also exist.
As a means for solving the above-described problems, one embodiment of the present disclosure may provide 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.
According to one embodiment, the method may further comprise before the temperature increasing process, a stopping an operation of the cooler.
According to one embodiment, the pressure at which solid state ice can sublimate into gas state vapor may range from 10−2 torr to 10−3 torr.
According to one embodiment, the roughing process may include 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.
According to one embodiment, the roughing process may include closing the roughing valve when the temperature of the first panel reaches a predetermined temperature after the roughing valve has been opened.
According to one embodiment, the purging process may include 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.
The above-described means for solving the problems are merely exemplary and should not be interpreted as intending to limit the disclosure. In addition to the aforementioned exemplary embodiments, additional embodiments described in the drawings and the detailed description of the invention may also exist.
According to any one of the above-described means for solving the problems of the present disclosure, it is possible to provide a cryopump configured to increase temperatures of a radiation shield and a first panel by turning on a first heater to directly sublimate solid state ice into gas state vapor.
It is possible to provide a cryopump configured to maintain and manage the environment where water undergoes direct sublimation from solid into gas during phase transition according to adjusting the temperature and pressure inside the cryopump by controlling a roughing valve configured to regulate vacuum within a 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 to regulate the temperature and pressure inside the cryopump.
It is possible to provide a cryopump configured to reduce the regeneration time required by the cryopump by eliminating the factors that cause the generation of H2O, which is a liquid accumulated at the bottoms of a radiation shield and a first panel.
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.
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.
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.
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.
Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.
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.
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.
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.
The roughing valve 250 is configured to regulate vacuum within the cryopump vessel 230.
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.
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 10−2 torr to 10−3 torr.
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
Referring to
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 10−2 torr to 10−3 torr 430.
That is, according to the present disclosure, when the regeneration process is performed at a maintained pressure of 10−2 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.
Further, it is possible to eliminate the factors that cause the generation of liquid H2O 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.
Referring back to
In a process S340, the cryopump 200 may lower the temperatures of the first panel 220 and the second panel 221.
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.
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.
The method for regenerating the cryopump performed in the cryopump as described above with reference to
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.
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.
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2022-0114244 | Sep 2022 | KR | national |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/KR2023/013427 | Sep 2023 | WO |
| Child | 19073144 | US |
