KR-102962143-B1 - Cryopump

KR102962143B1KR 102962143 B1KR102962143 B1KR 102962143B1KR-102962143-B1

Abstract

A cryopump is disclosed comprising: a pump inlet; a two-stage chiller; a first-stage array thermally coupled to the first stage of the two-stage chiller; and a cryopanel structure coupled to the second stage of the two-stage chiller. The cryopanel structure comprises at least three flat panels. The first-stage array is mounted between the pump inlet and the cryopanel structure and comprises a plurality of slats, each of which is mounted such that the side of each of the plurality of slats closest to the cryopanel structure is substantially aligned with a corresponding one of the at least three flat panels and is longitudinally offset therefrom.

Inventors

샤렉 제럴드

Assignees

에드워즈 배큠 엘엘시

Dates

Publication Date: 20260508
Application Date: 20210706
Priority Date: 20200708

Claims (16)

In cryopumps, Pump inlet; 2-stage chiller; A first stage array thermally coupled to the first stage of the above two-stage refrigerator; and It includes a cryopanel structure coupled to the second stage of the above two-stage refrigerator, and The above cryopanel structure comprises at least three flat panels, and The first stage array is mounted between the pump inlet and the cryopanel structure and includes a plurality of slats, wherein each of the plurality of slats is mounted such that the edge of each of the plurality of slats closest to the cryopanel structure is parallel to one of the corresponding upper edges of the at least three planar panels and is spaced longitudinally from the upper edge. Cryopump.
In Article 1, The plurality of slats are mounted to extend toward the pump inlet at an angle between 110° and 160° with respect to the flat panel. Cryopump.
In Article 1, The plurality of slats are mounted such that at least a portion of the plurality of slats shields one surface of an adjacent flat panel of the cryopanel structure from gas molecules entering the pump through the pump inlet. Cryopump.
In Paragraph 3, The surfaces of the above-mentioned at least three flat panels include a coated portion coated with an adsorption material and an additional portion not coated with said adsorption material. Cryopump.
In Article 4, In at least some of the at least three flat panels, one surface is a coated surface coated with the adsorption material, and another surface is an uncoated surface. Cryopump.
In Article 5, The above coating surface is shielded by one of the adjacent slats. Cryopump.
In any one of paragraphs 1 to 6, The plurality of slats are arranged parallel to each other, and the at least three flat panels are arranged parallel to each other. Cryopump.
In any one of paragraphs 1 to 6, The above at least three flat panels are arranged to extend parallel to the longitudinal axis of the pump. Cryopump.
In any one of paragraphs 1 to 6, The plurality of slats and the at least three flat panels are rectangular. Cryopump.
In any one of paragraphs 1 to 6, The plurality of slats are configured to overlap when viewed through the pump inlet in a direction parallel to the flat panel. Cryopump.
In any one of paragraphs 1 to 6, The above at least three flat panels are all of the same size. Cryopump.
In any one of paragraphs 1 to 6, The above plurality of slats are all of the same size. Cryopump.
In any one of paragraphs 1 to 6, The flat panel arranged at the end among the above at least three flat panels is smaller in size than the flat panel arranged at the center side with respect to the flat panel arranged at the end, and Among the plurality of slats above, the slat arranged at the end is smaller in size than the slat arranged at the center side with respect to the slat arranged at the end. Cryopump.
In any one of paragraphs 4 through 6, The above adsorption material is configured to adsorb Type III gases such as hydrogen, helium, and neon. Cryopump.
In any one of paragraphs 4 through 6, The above adsorption material includes a molecular sieve that coats the coating portion. Cryopump.
In any one of paragraphs 4 through 6, The above adsorption material comprises one of charcoal, activated carbon, zeolite, or a porous metal surface. Cryopump.

Description

Cryopump The field of the present invention relates to cryopumps, and in particular to two-stage cryopumps having a first stage of temperature for capturing a type I gas such as water vapor, and a second stage of low temperature for capturing a type II gas such as nitrogen and, in some embodiments, for freeze-adsorbing a type III gas such as hydrogen. The two-stage cryopump is formed by a low-temperature second-stage cryopanel array. This can operate in the range of 4 to 25 Kelvin (K) and can be coated with a capture material such as charcoal. This cryopanel array serves as a primary pumping surface and is surrounded by a first-stage radiation shield, which operates in a high-temperature range such as 40 to 130 K, provides radiation shielding to the low-temperature array, and shields the array from Type I gases such as water vapor by capturing these gas molecules in contact with the array. During operation, as gas passes through the inlet into the pump vessel, at least some of the Type I gases, such as water vapor, condense on the front array forming part of the first stage radiation shield. Gases with lower boiling points pass through the front array and enter the volume within the radiation shield. Type II gases, such as nitrogen, condense on the second stage array, while Type III gases, such as hydrogen, helium, and neon, which have a vapor pressure detectable at 4K, are adsorbed by an adsorbent such as activated carbon, zeolite, or a molecular sieve coating the second stage cryopanel. In this way, gas entering the pump from the chamber is captured, and a vacuum is created within the pump vessel. One problem with the cryopump is that its ability to capture gas molecules decreases as the capture surface becomes saturated with gas molecules during operation. Therefore, the cryopump is periodically regenerated to release the captured gas molecules. When designing a cryopump, there are competitive factors to consider. While high gas conductance to the pump improves pumping speed, it is advantageous to provide partial shielding of the second-stage cryopanel from thermal radiation to reduce the thermal load on the cryopanel and from Type I gas molecules. Type I gases reaching the cryopanel condense there, blocking Type III gases from freezing and adsorbing. Additionally, some Type I gases, such as large-chain hydrocarbons, do not leave the array surface during regeneration, causing a degradation in pumping performance over the remaining life of the pump. However, shielding the cryopanel from gas molecules results in a reduction in conductance. It would be desirable to provide an improved two-stage cryopump. A first embodiment provides a cryopump comprising: a pump inlet; a two-stage chiller; a first-stage array thermally coupled to the first stage of the two-stage chiller; and a cryopanel structure coupled to the second stage of the two-stage chiller, wherein the cryopanel structure comprises at least three flat panels, and the first-stage array is mounted between the pump inlet and the cryopanel structure and comprises a plurality of slats, each of the plurality of slats is mounted such that the edge of each of the plurality of slats closest to the cryopanel structure is parallel to the upper edge of a corresponding one of the at least three flat panels and is spaced longitudinally from the upper edge. When designing a cryopump, it is desirable to provide a cryopump structure having a first stage or front array to have a substantial surface area capable of capturing gas molecules and to provide partial shielding of the cryopump structure from thermal radiation and from some gas molecules entering the pump through the inlet. The cryopump inlet is typically circular in cross-section, and the cryopump structure generally has a similar configuration, perhaps formed as a coaxial cylinder. While such an arrangement has the advantages of symmetry and good alignment with the vacuum chamber outlet, it can be difficult to manufacture and construct. Providing a planar second-stage cryopump array formed of flat panels having a first-stage array of linear slats aligned with at least a portion of the panel and longitudinally offset relative to the panel provides an arrangement that is simple to manufacture and facilitates assembly. Additionally, having an arrangement where the slats are substantially aligned with the panel provides both effective and targeted shielding of the panel. Such an arrangement can also provide very high hydrogen pumping rates. In some embodiments, each of the plurality of panels has a corresponding slat that is aligned longitudinally with the panel and offset relative to the panel. In some embodiments, the plurality of slats are mounted to extend at an angle between 110° and 160° relative to the flat panel toward the pump inlet. By adjusting the angle of the slats so that they are inclined toward the pump inlet and the adjacent panel, the cryopanel structure can be effectively shielded. In some em