Cryopump

Abstract

To inhibit occurrence of dew condensation on an outer surface of a cryopump.SOLUTION: A cryopump 20 includes: a housing 21; a shield 25 which is disposed so as to face an inner surface 22a of the housing 21 and configured to be cooled, thereby condensing a gas in the housing 21 and causing the gas to adhere to the shield 25; and an introduction unit 40 which introduces a regeneration gas G into a gap 30 between the housing 21 and the shield 25. The introduction unit 40 forms a spiral swirl flow flowing spirally along the inner surface 22a of the housing 21 with the regeneration gas G.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a cryopump. [Background technology]

[0002] Cryopumps have traditionally been used as one type of device for creating a high vacuum inside a vacuum chamber. A cryopump includes cooling elements such as a shield, baffle, and cryopanel housed in a housing and thermally connected to a refrigerator. When the cryopump is connected to the vacuum chamber, the refrigerator cools the cooling elements to extremely low temperatures, causing gas inside the housing to condense on or be adsorbed onto the cooling elements. This evacuates the space inside the vacuum chamber, creating a high vacuum inside the vacuum chamber. Patent Document 1 discloses an example of such a cryopump. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-143646 Summary of the Invention [Problem to be solved by the invention]

[0004] In a cryopump, if solidified gas in the vacuum chamber adheres to the cooling element, the pumping efficiency of the cryopump decreases. Therefore, a regeneration process is performed in which the flow path between the vacuum chamber and the cryopump is blocked, the temperature inside the cryopump is raised, and the material adhering to the cooling element is liquefied or vaporized for removal. In this regeneration process, a regeneration gas is introduced into the cryopump. Under high vacuum conditions, gas-mediated heat conduction between the cooling element and the housing is extremely low. When regeneration gas is introduced into the cryopump from this state, heat is conducted between the cooling element and the housing via the introduced regeneration gas, rapidly cooling the housing. This can cause condensation on the outer surface of the housing. If the resulting water droplets fall on the equipment surrounding the cryopump, they may malfunction.

[0005] The present invention has been made in consideration of the above points, and an object of the present invention is to prevent condensation from occurring on the outer surface of a cryopump. [Means for solving the problem]

[0006] The cryopump according to the present invention comprises: [1] The housing and a shield disposed to face the inner surface of the housing, the shield being configured so that gas within the housing condenses and adheres to the shield when the shield is cooled; an introduction unit that introduces a hot gas into the gap between the housing and the shield, The introduction unit is a cryopump that uses the hot gas to form a vortex flow that flows spirally along the inner surface of the housing.

[0007] The cryopump according to the present invention comprises: [2] The introduction unit is the cryopump according to [1], which has an introduction pipe that introduces the regeneration gas into the housing, and an opening in the housing through which the introduction pipe opens.

[0008] The cryopump according to the present invention comprises: [3] [2] The cryopump according to [2], wherein the inlet pipe extends in a direction inclined with respect to the axial direction so as to move toward the downstream side of the flow of the regeneration gas as the inlet pipe approaches the housing.

[0009] The cryopump according to the present invention comprises: [4] The introduction unit has a guide tube disposed inside the housing, The cryopump according to [2] or [3], wherein the guide pipe has an inclined portion that extends so as to approach a central axis as it moves from the upstream side to the downstream side of the flow of the regeneration gas.

[0010] The cryopump according to the present invention comprises: [5] [4] The cryopump according to [4], wherein the entire opening is located within the section in the axial direction in which the inclined portion is arranged.

[0011] The cryopump according to the present invention comprises: [6] The cryopump according to [4] or [5], wherein the guide pipe further has a parallel section connected to the downstream end of the inclined section and extending parallel to the central axis. [Effects of the Invention]

[0012] According to the present invention, it is possible to prevent condensation from occurring on the outer surface of the cryopump. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram for explaining an embodiment of the present invention, and is a diagram that schematically shows an example of a vacuum processing system including a cryopump. [Figure 2] FIG. 2 is a vertical cross-sectional view showing an example of a cryopump. [Figure 3] FIG. 3 is a cross-sectional view of the cryopump taken along line III-III in FIG. [Figure 4] FIG. 4 is a vertical cross-sectional view showing a modified example of a cryopump. [Figure 5] FIG. 5 is a vertical cross-sectional view showing another modified example of the cryopump. DETAILED DESCRIPTION OF THE INVENTION

[0014] An embodiment of the present invention will be described below with reference to the drawings. In the drawings attached to this specification, the scale and aspect ratios may be appropriately changed and exaggerated from those of the actual objects for the sake of convenience in illustration and understanding.

[0015] Furthermore, terms used in this specification that specify shapes, geometric conditions, and their degrees, such as "parallel," "orthogonal," and "identical," as well as values ​​of lengths and angles, are not to be construed as being bound by strict meanings, but rather as including a range within which similar functions can be expected.

[0016] In this specification, the direction in which the central axis A of the cryopump 20 extends is referred to as the axial direction da, the direction perpendicular to the axial direction da is referred to as the radial direction dr, and the direction along the circumference around the central axis A is referred to as the circumferential direction dc. In addition, along the radial direction dr, the side approaching the central axis A is referred to as the inner side, and the side away from the central axis A is referred to as the outer side.

[0017] Fig. 1 is a diagram for explaining one embodiment of the present invention, and is a diagram schematically showing an example of a vacuum processing system 10 including a cryopump 20. Fig. 2 is a vertical cross-sectional view showing the example of the cryopump 20. Fig. 3 is a horizontal cross-sectional view of the cryopump 20 corresponding to line III-III in Fig. 2.

[0018] The vacuum processing system 10 shown in FIG. 1 includes a vacuum chamber 12, a gate valve 14, a refrigerator 16, a regeneration gas supply device 18, and a cryopump 20. The cryopump 20 is connected to the vacuum chamber 12 via the gate valve 14. In this vacuum processing system 10, the vacuum chamber 12 is evacuated by condensing and removing gas from the vacuum chamber 12 using the cryopump 20. The gate valve 14 opens and closes a flow path formed between the vacuum chamber 12 and the cryopump 20. The vacuum chamber 12 has an opening 13. The opening 13 faces the gate valve 14. When the gate valve 14 is open, the opening 13 communicates with an opening 24 (described below) of the cryopump 20. The refrigerator 16 cools cooling members such as a shield 25 included in the cryopump 20. The regeneration gas supply device 18 supplies regeneration gas during a regeneration process in the cryopump 20. The vacuum processing system 10 may include another vacuum pump for roughing the inside of the vacuum chamber 12. The other vacuum pump is preferably connected to the cryopump 20 and configured to be able to rough evacuate the inside of the cryopump 20.

[0019] The cryopump 20 is a type of vacuum pump. The cryopump 20 includes a housing 21, a shield 25, and an introduction unit 40. In the example shown in Fig. 2, the cryopump 20 further includes a baffle 32, a cryopanel 34, a first stage 36, and a second stage 38.

[0020] The cryopump 20 has a central axis A. The housing 21 is a component that constitutes the outer shell of the cryopump 20. The housing 21 has a generally cylindrical shape with a bottom and includes a side wall portion 22 and a bottom wall portion 23. In this embodiment, the side wall portion 22 has a cylindrical shape. The central axis of the side wall portion 22 coincides with the central axis A. The bottom wall portion 23 is connected to the lower end of the side wall portion 22. The bottom wall portion 23 has a circular outline when viewed along the central axis A. A flange portion extending outward in the radial direction dr may be formed at the upper end of the side wall portion 22. The housing 21 has an opening 24 on the opposite side of the bottom wall portion 23 in the axial direction da. The opening 24 faces the gate valve 14. The opening 24 communicates with the opening 13 of the vacuum chamber 12 when the gate valve 14 is in an open state. As a result, when the gate valve 14 is in an open state, the internal space of the vacuum chamber 12 and the internal space of the cryopump 20 communicate with each other. The housing 21 has a sufficient thickness to withstand the pressure difference that occurs between the inside and outside of the cryopump 20 when the inside of the cryopump 20 is in a high vacuum state. Such a housing 21 is formed of a metal material such as stainless steel.

[0021] The first stage 36 and the second stage 38 are each thermally connected to the refrigerator 16. In the example shown in Fig. 2, the shield 25 is connected to the first stage 36, and the cryopanel 34 is connected to the second stage 38. The first stage 36 and the second stage 38 are preferably made of a material with high thermal conductivity. For example, the first stage 36 and the second stage 38 are made of a metal material such as stainless steel.

[0022] The shield 25 is configured so that, as the shield 25 is cooled, gas within the housing 21 condenses and adheres to the shield 25. The shield 25 is thermally connected to the first stage 36. Therefore, the shield 25 is cooled by the refrigerator 16 via the first stage 36. The shield 25 has a generally cylindrical shape with a bottom and includes a side wall portion 26 and a bottom wall portion 27. In this embodiment, the side wall portion 26 has a cylindrical shape. The central axis of the side wall portion 26 coincides with the central axis A. The bottom wall portion 27 is connected to the lower end of the side wall portion 26. The bottom wall portion 27 has a circular outline when viewed along the central axis A. In the example shown in FIG. 2, the bottom wall portion 27 is connected to the first stage 36. The shield 25 is preferably formed of a material with high thermal conductivity. For example, the shield 25 is formed of a metal material such as stainless steel.

[0023] The shield 25 is disposed so as to face the inner surface 22a of the housing 21. In particular, the outer surface of the side wall portion 26 of the shield 25 faces the inner surface 22a of the side wall portion 22 of the housing 21. The side wall portion 26 and the side wall portion 22 may be disposed parallel to each other. In this case, the side wall portion 26 and the side wall portion 22 are disposed concentrically when viewed from the axial direction da. Furthermore, the bottom wall portion 27 of the shield 25 faces the bottom wall portion 23 of the housing 21. The bottom wall portion 27 and the bottom wall portion 23 may be disposed parallel to each other. A gap 30 is formed between the outer surface of the side wall portion 26 of the shield 25 and the inner surface 22a of the side wall portion 22 of the housing 21. As shown in FIGS. 2 and 3 , the gap 30 has a generally cylindrical shape.

[0024] The baffle 32 is disposed in the opening 24. Therefore, the gas in the vacuum chamber 12 flows through the baffle 32 into the cryopump 20, particularly into the shield 25. The baffle 32 is cooled by the refrigerator 16 and has the function of condensing the gas in the vacuum chamber 12. The baffle 32 may be thermally connected to the shield 25. In this case, the baffle 32 is cooled by the refrigerator 16 via the shield 25 and the first stage 36.

[0025] The cryopanel 34 is a component that is cooled by the refrigerator 16 and condenses the gas in the vacuum chamber 12. The cryopanel 34 is thermally connected to the second stage 38. Therefore, the cryopanel 34 is cooled by the refrigerator 16 via the second stage 38. In the example shown in FIG. 2, the cryopanel 34 has a cylindrical shape with a bottom and a bottom wall portion at the upper end, but the specific shape of the cryopanel 34 is not particularly limited.

[0026] The introduction unit 40 is a device for introducing regeneration gas G into the internal space of the cryopump 20. In the cryopump 20, if substances formed by condensation or solidification of gas in the vacuum chamber 12 adhere to cooling components such as the shield 25, baffle 32, and cryopanel 34, the pumping efficiency of the cryopump 20 decreases. For this reason, a regeneration process is performed in which the gate valve 14 is closed, the temperature inside the cryopump 20 is raised, and the substances adhered to the cooling components are liquefied or vaporized for removal. In this regeneration process, regeneration gas G is introduced into the cryopump 20 using the introduction unit 40. In a high vacuum state, heat conduction through the gas between the shield 25 and the housing 21 is extremely small. When regeneration gas G is introduced into the cryopump 20 from this state using the introduction unit 40, heat conduction occurs between the shield 25 and the housing 21 via the introduced regeneration gas G, rapidly cooling the housing 21. This can cause condensation on the outer surface of the housing 21. If water droplets resulting from condensation fall onto devices around the cryopump 20, there is a risk of causing malfunctions in those devices.

[0027] To address this problem, in this embodiment, the introduction unit 40 introduces the regeneration gas G into the gap 30 between the casing 21 and the shield 25. The introduction unit 40 has an introduction pipe 42. The introduction pipe 42 is a pipe for introducing the regeneration gas G supplied from the regeneration gas supply device 18 into the casing 21. An opening 44 through which the introduction pipe 42 opens is provided in the side wall 22 of the casing 21. At the opening 44, the introduction pipe 42 opens into the inner surface 22a of the side wall 22. The opening 44 is located below the side wall 22, i.e., near the bottom wall 23. Therefore, the regeneration gas G introduced into the casing 21 from the opening 44 flows mainly upward (toward the opening 24) through the gap 30 between the casing 21 and the shield 25.

[0028] It is preferable that at least a portion of the opening 44 faces the side wall portion 26 of the shield 25 in the radial direction dr. In other words, it is preferable that at least a portion of the opening 44 overlaps with the shield 25 when viewed in the radial direction dr. In this case, at least a portion of the regeneration gas G introduced into the housing 21 from the opening 44 flows directly into the gap 30. In the example shown in FIG. 2 , a portion of the opening 44 faces the side wall portion 26 of the shield 25 in the radial direction dr. Another portion of the opening 44 faces the gap formed between the bottom wall portion 27 of the shield 25 and the bottom wall portion 23 of the housing 21 in the radial direction dr. However, this is not limiting, and the entire opening 44 may face the side wall portion 26 of the shield 25 in the radial direction dr.

[0029] 2, the introduction unit 40 causes the regeneration gas G to form a vortex flow that flows spirally along the inner surface 22a of the casing 21. This increases the amount of heat transferred from the regeneration gas G to the casing 21 (side wall portion 22), allowing the temperature of the casing 21 to rise quickly. Furthermore, the vortex flow of the regeneration gas G allows the temperature of the casing 21 to rise uniformly.

[0030] As shown in FIG. 3 , the inlet pipe 42 extends in a direction inclined with respect to the radial direction dr at the opening 44. The intersection point C between the central axis B of the inlet pipe 42 and the extension plane of the side wall portion 22 at the opening 44. The radial direction dr is defined along the line connecting the central axis A and point C in the cross section shown in FIG. 3 . The smaller of the two angles formed between the central axis B and the radial direction dr at the opening 44 is defined as angle θ. The angle θ is, for example, between 30 degrees and 90 degrees. The angle θ may also be between 40 degrees and 80 degrees. The inlet pipe 42 extends perpendicular to the axial direction da. However, the inlet pipe 42 may extend in a direction inclined with respect to the axial direction da at an angle greater than 0 degrees and less than 90 degrees. In particular, the inlet pipe 42 may extend in a direction inclined with respect to the axial direction da so as to move toward the opening 24 (upward in FIG. 2 ) as it approaches the side wall portion 22. In the example shown in FIGS. 2 and 3, the introduction pipe 42 extends in a straight line, but is not limited to this, and the introduction pipe 42 may include a portion that extends in a curved line.

[0031] The introduction pipe 42 may extend in a direction inclined with respect to the axial direction da so as to move toward the downstream side of the flow of the regeneration gas G as it approaches the casing 21. In the example shown in Fig. 2, the side of the opening 44 along the axial direction da (the upper side in Fig. 2) is the downstream side of the flow of the regeneration gas G. An introduction unit 40 having such an introduction pipe 42 can more appropriately form a vortex flow of the regeneration gas G that flows spirally along the inner surface 22a of the casing 21.

[0032] The regeneration gas G may be, for example, an inert gas such as nitrogen gas (N2 gas). The regeneration gas G may have a temperature of room temperature or higher. For example, the regeneration gas G may have a temperature of 100°C or higher and 500°C or lower. Preferably, the regeneration gas G may have a temperature of 200°C or higher and 300°C or lower. In this case, the regeneration gas G may be heated in the regeneration gas supply device 18 to a predetermined temperature.

[0033] The cryopump 20 may have other components such as a thermometer, a pressure gauge, a safety valve, and a drain pipe. For example, the thermometer may be configured to measure the temperature of each component of the cryopump 20 and / or the temperature of the internal space of the cryopump 20. The pressure gauge may be configured to measure the internal pressure of the cryopump 20. The drain pipe may be configured to discharge liquid accumulated in the cryopump 20.

[0034] Next, the operation of the cryopump 20 will be described. When exhausting gas from the vacuum chamber 12, the gate valve 14 may first be opened, and another vacuum pump (not shown) may be used to roughly evacuate the gas from the vacuum chamber 12 and the cryopump 20. The cryopump 20 may then be used to further reduce the pressure inside the vacuum chamber 12. When the cryopump 20 is operated, the refrigerator 16 is used to cool the first stage 36 and the second stage 38. In this embodiment, the shield 25 and the baffle 32 are connected to the first stage 36. Therefore, the shield 25 and the baffle 32 are cooled by the refrigerator 16 via the first stage 36. The shield 25 and the baffle 32 are cooled to a temperature of, for example, 130 K or less. The cryopanel 34 is connected to the second stage 38. Therefore, the cryopanel 34 is cooled by the refrigerator 16 via the second stage 38. The cryopanel 34 is cooled to a temperature lower than that of the shield 25 and the baffle 32, for example, to a temperature of 20 K or less.

[0035] Gas (e.g., air) flowing from the vacuum chamber 12 into the cryopump 20 first comes into contact with the shield 25 and the baffle 32. At this time, water vapor, which has a relatively high condensation temperature, condenses and adheres to the shield 25 and the baffle 32. The gas then comes into contact with the cryopanel 34. At this time, nitrogen (N2), oxygen (O2), argon (Ar), and other gases, which have relatively low condensation temperatures, condense and adhere to the cryopanel 34. The cryopump 20 may also have an adsorbent that adsorbs hydrogen (H2), helium (He), and other gases, which have even lower condensation temperatures. In this way, the gas in the vacuum chamber 12 is condensed or adsorbed by the cryopump 20. This reduces the pressure inside the vacuum chamber 12. That is, the cryopump 20 functions as a vacuum pump.

[0036] When gas is condensed and the amount of material adhering to the shield 25, the baffle 32, and the cryopanels 34 increases, the pumping efficiency of the cryopump 20 decreases. In this case, a regeneration process is performed in which the temperature inside the cryopump 20 is increased to liquefy or vaporize the material adhering to the shield 25, the baffle 32, and the cryopanels 34 and remove it.

[0037] In the regeneration step, first, the gate valve 14 is closed to block the flow path between the vacuum chamber 12 and the cryopump 20. Next, the introduction unit 40 is used to introduce the regeneration gas G into the cryopump 20. The introduction unit 40 introduces the regeneration gas G into the gap 30 between the housing 21 and the shield 25.

[0038] In particular, in this embodiment, the introduction unit 40 causes the regeneration gas G to form a vortex flow that flows spirally along the inner surface 22a of the casing 21. As shown in FIG. 3, the introduction pipe 42 extends in a direction inclined with respect to the radial direction dr at the opening 44. As a result, a force that moves in a direction rotating about the central axis A acts on the regeneration gas G introduced from the introduction pipe 42 into the casing 21. Therefore, the regeneration gas G introduced into the casing 21 flows upward along the inner surface 22a of the casing 21 while rotating about the central axis A. As a result, as shown in FIG. 2, the regeneration gas G introduced into the casing 21 forms a vortex flow that flows spirally from bottom to top along the inner surface 22a.

[0039] The formation of a vortex flow of the regeneration gas G increases the amount of heat transferred from the regeneration gas G to the casing 21 (side wall portion 22), allowing the temperature of the casing 21 to rise quickly. Furthermore, the vortex flow of the regeneration gas G allows the temperature of the casing 21 to rise uniformly. The rapid rise in temperature of the casing 21 can prevent condensation from forming on the outer surface of the casing 21. This prevents water droplets caused by condensation from falling onto devices surrounding the cryopump 20 and causing malfunctions in those devices.

[0040] When the temperature inside the cryopump 20 rises, substances adhering to the shield 25, the baffle 32, and the cryopanel 34 are vaporized or liquefied. The vaporized substances may be discharged to the outside of the cryopump 20 via a valve and a discharge pipe (not shown). The liquefied substances may be discharged to the outside of the cryopump 20 via a drain pipe (not shown).

[0041] Once the exhaust of the vaporized or liquefied substance is complete, another vacuum pump (not shown) is used to rough pump the gas inside the cryopump 20. Thereafter, the first stage 36 and the second stage 38 are cooled using the refrigerator 16, and the pressure inside the cryopump 20 is further reduced. When the pressure inside the cryopump 20 becomes approximately the same as the pressure inside the vacuum chamber 12, the gate valve 14 is opened, and the pressure inside the vacuum chamber 12 continues to be reduced. In this way, by repeating the depressurization process and regeneration process inside the vacuum chamber 12, the inside of the vacuum chamber 12 can be brought to a high vacuum state.

[0042] The cryopump 20 of this embodiment includes a housing 21, a shield 25 arranged to face the inner surface 22a of the housing 21, and configured so that when the shield 25 is cooled, the gas inside the housing 21 condenses and adheres to the shield 25, and an introduction unit 40 that introduces regeneration gas G into the gap 30 between the housing 21 and the shield 25, and the introduction unit 40 forms a vortex flow by the regeneration gas G that flows spirally along the inner surface 22a of the housing 21.

[0043] In the cryopump 20 of this embodiment, the introduction unit 40 may have an introduction pipe 42 that introduces the regeneration gas G into the housing 21 and an opening 44 in the housing 21 through which the introduction pipe 42 opens.

[0044] According to this cryopump 20, a vortex flow of the regeneration gas G is formed, which increases the amount of heat transferred from the regeneration gas G to the casing 21 (side wall portion 22), thereby enabling the temperature of the casing 21 to be raised quickly. Furthermore, the vortex flow of the regeneration gas G enables the temperature of the casing 21 to be raised uniformly. The rapid rise in temperature of the casing 21 can prevent condensation from forming on the outer surface of the casing 21. This prevents water droplets caused by condensation from falling on devices around the cryopump 20 and causing malfunctions in those devices.

[0045] In the cryopump 20 of this embodiment, the introduction pipe 42 may extend in a direction inclined with respect to the axial direction da so as to move toward the downstream side of the flow of the regeneration gas G as it approaches the housing 21.

[0046] According to the cryopump 20, the vortex flow of the regeneration gas G that flows in a spiral shape along the inner surface 22a of the housing 21 can be more appropriately formed.

[0047] A modified example of this embodiment will be described with reference to Figures 4 and 5. In the following description and the drawings used in the following description, parts that can be configured similarly to the above-described embodiment will be designated by the same reference numerals as those used for the corresponding parts in the above-described embodiment, and duplicated descriptions will be omitted.

[0048] Fig. 4 is a longitudinal cross-sectional view showing a modified example of the cryopump 20. In the example shown in Fig. 4, the introduction unit 40 has a guide pipe 50 arranged inside the housing 21. The guide pipe 50 has an inclined portion 52. The inclined portion 52 extends so as to approach the central axis A as it moves from the upstream side to the downstream side of the flow of the regeneration gas G.

[0049] The guide tube 50 is made of, for example, metal. The thickness of the guide tube 50 may be smaller than the thickness of the housing 21. The central axis of the guide tube 50 coincides with the central axis A of the housing 21. That is, the guide tube 50 extends along the central axis A. The upstream (lower) end of the inclined portion 52 is fixed to the housing 21. In this way, the guide tube 50 is attached to the housing 21.

[0050] The regeneration gas G introduced into the casing 21 through the opening 44 is guided by the inclined portion 52 and flows toward the gap 30. In the example shown in FIG. 4 , the entire opening 44 is located within the section in the axial direction da where the inclined portion 52 of the guide pipe 50 is arranged. In other words, the entire opening 44 overlaps with the inclined portion 52 when viewed from the radial direction dr. In this case, most of the regeneration gas G introduced into the casing 21 through the opening 44 is guided by the inclined portion 52 and flows toward the gap 30. Therefore, the regeneration gas G can be more appropriately guided toward the gap 30. However, this is not limited to this, and only a portion of the opening 44 may be located within the section in the axial direction da where the inclined portion 52 of the guide pipe 50 is arranged.

[0051] In this modified cryopump 20, the introduction unit 40 has a guide pipe 50 arranged inside the housing 21, and the guide pipe 50 has an inclined portion 52 that extends so as to approach the central axis A as it moves from the upstream side to the downstream side of the flow of the regeneration gas G.

[0052] According to such a cryopump 20 , the regeneration gas G introduced into the housing 21 from the opening 44 can be guided by the inclined portion 52 and flow toward the gap 30 .

[0053] In the cryopump 20 of this modification, the entire opening 44 may be located within the section in the axial direction da where the inclined portion 52 is arranged. Therefore, the regeneration gas G can be appropriately guided toward the gap 30.

[0054] According to this cryopump 20, most of the regeneration gas G introduced into the housing 21 through the opening 44 is guided by the inclined portion 52 and flows toward the gap 30. Therefore, the regeneration gas G can be more appropriately guided toward the gap 30.

[0055] FIG. 5 is a longitudinal cross-sectional view showing another modified example of the cryopump 20. In the example shown in FIG. 5, the guide tube 50 has an inclined portion 52 and a parallel portion 54. The inclined portion 52 may be configured similarly to the inclined portion 52 in the example shown in FIG. 4. The parallel portion 54 is connected to the downstream end of the inclined portion 52. The parallel portion 54 is a cylindrical portion extending parallel to the central axis A.

[0056] Since the guide pipe 50 has the parallel portion 54, the regeneration gas G guided by the inclined portion 52 is guided by the parallel portion 54 toward the gap 30. Therefore, the regeneration gas G can be more appropriately guided toward the gap 30.

[0057] In the cryopump 20 of this modification, the guide pipe 50 further has a parallel portion 54 that is connected to the downstream end of the inclined portion 52 and extends parallel to the central axis A.

[0058] According to such a cryopump 20, the regeneration gas G guided by the inclined portion 52 is guided by the parallel portion 54 toward the gap 30. Therefore, the regeneration gas G can be more appropriately guided toward the gap 30. [Explanation of symbols]

[0059] 10 Vacuum Processing System 12 Vacuum chamber 14 Gate valve 16 Refrigeration Machine 18 Regenerative gas supply device 20 Cryopump 21. Cabinet 22 Side wall 22a Inner surface 24 Opening 23 Bottom wall 25 Shield 26 Side wall 27 Bottom wall 30 Gap 32 Baffle 34 Cryopanel 36 Stage 1 38 Second Stage 40 Introductory Unit 42 Introductory tube 44 Opening 50 Guide tube 52 Slope 54 Parallel section G Regenerated gas A Center axis da axial direction dr radial direction dc circumferential direction

Claims

1. The housing and a shield disposed to face the inner surface of the housing, the shield being configured so that gas within the housing condenses and adheres to the shield when the shield is cooled; an introduction unit that introduces a regeneration gas into the gap between the housing and the shield, The introduction unit forms a vortex flow by the regeneration gas that flows spirally along the inner surface of the housing.

2. 2. The cryopump according to claim 1, wherein the introduction unit has an introduction pipe that introduces the regeneration gas into the housing, and an opening in the housing through which the introduction pipe opens.

3. 3. The cryopump according to claim 2, wherein the inlet pipe extends in a direction inclined with respect to the axial direction so as to move toward a downstream side of the flow of the regeneration gas as the inlet pipe approaches the housing.

4. The introduction unit has a guide tube disposed inside the housing, 3. The cryopump according to claim 2, wherein the guide pipe has an inclined portion that extends so as to approach a central axis as it moves from an upstream side to a downstream side in the flow of the regeneration gas.

5. The cryopump according to claim 4 , wherein the entire opening is located within a section in the axial direction in which the inclined portion is arranged.

6. 6. The cryopump according to claim 4, wherein the guide pipe further includes a parallel portion connected to the downstream end of the inclined portion and extending parallel to the central axis.

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