JP2009062892A - Cryopanel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cryopanel improved in exhaust gas speed, and solidification and adsorption efficiency. <P>SOLUTION: A panel part 12 of the cryopanel 10 includes a plurality of panel pieces 12A. Each panel piece 12A is a plate shape member having a U-shape section and has an active layer formed on an inside surface of the U-shape. The panel piece 12A comprises a first plate part 12a positioned at the center of the U-shape, and a pair of second plate parts 12b positioned at both ends of the first plate part 12a. The first plate part 12a of one panel piece 12A is connected to the second plate part 12b of another panel piece 12A and the same are connected in a mosaic shape to extend from a heat transfer plate 11. Also, each panel piece 12A is arranged to orient the U-shape in one of directions of an upstream direction, a side outer direction, or a downstream direction of a gas channel. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cryopanel used for a cryopump.

  In a semiconductor manufacturing apparatus, a cryopump is used to realize a high vacuum. The cryopump realizes a high vacuum by cooling a cryopanel in a vacuum vessel and solidifying or adsorbing molecules.

  A conventional cryopanel is connected to a stage of a cooler and has a disk-like panel whose surface is arranged (horizontally) in a gas inflow direction, and a gas panel arranged on the back side of the disk-like panel. A plurality of elongated plate-like panels extending in the downstream direction of the inflow direction.

  The gas in the processing chamber flows from the upper opening of the vacuum vessel, water molecules are solidified mainly by a louver disposed above the cryopanel, and argon and nitrogen other than water molecules are mainly formed by a disk-shaped panel. Hydrogen, helium, or the like that is solidified and does not freeze at an extremely low temperature is adsorbed to the adsorption layers formed on both sides of the elongated plate-like panel (see, for example, Patent Document 1).

A cryopanel has also been proposed in which a plurality of conical panels are arranged along the gas inflow direction. This conical panel is an annular panel obtained by cutting a conical slope with a constant width, and it has been proposed that such a conical panel is arranged in a plurality of stages along the gas flow path direction. (For example, see Patent Document 2)
JP-A-2-308985 US Patent Application Publication No. 2006/0064990

  By the way, in order to improve the exhaust speed, which is the main performance of the cryopump, it is necessary to improve the probability that hydrogen molecules are adsorbed on the adsorption layer.

  However, in the cryopanel described in Patent Document 1, the elongated plate-like panel on which the adsorption layer is formed is provided only on the back side of the disc-shaped panel (downstream side of the disc-shaped panel in the gas inflow direction). In plan view, the area ratio occupied by the flat panel in the vacuum vessel is large, so that the exhaust speed is limited due to the structure. Further, the elongate plate-like panel had particularly low coagulation / adsorption efficiency in the back of the disk-like panel.

  Further, since the cryopanel described in Patent Document 2 has an annular shape when viewed from the upper opening of the vacuum vessel, a sufficient flow path is not secured from the upstream side to the downstream side of the gas flow path. It was prominent in the center of the shape and in the shade of each panel. For this reason, the air permeability on the downstream side was lowered, and the coagulation / adsorption efficiency was low.

  In view of the above, an object of the present invention is to provide a cryopanel having improved exhaust speed and coagulation / adsorption efficiency.

  A cryopanel according to one aspect of the present invention includes a vacuum vessel having a gas inlet, and a refrigerator that includes a stage disposed in the vacuum vessel and cools the stage. A cryopanel used in a cryopump for solidifying or adsorbing molecules flowing into the vacuum vessel, a heat transfer plate held by the stage and cooled, and a gas in the vacuum vessel supported by the heat transfer plate It is a panel part arrange | positioned at a flow path, Comprising: The panel part containing a some plate-shaped panel piece of a U-shaped cross section is provided.

  Further, the panel piece may be a U-shaped panel piece in which a plate-like panel having a rectangular shape in plan view is bent evenly in the longitudinal direction.

  In addition, an active layer may be formed or attached to the inner surface of the U-shape of the panel piece.

  Moreover, the said panel piece may be arrange | positioned so that the said U-shape may face the direction of the upstream of the said gas flow path, a side outer side, or a downstream.

  The panel piece is composed of a first plate portion located in the center of the U-shape and a pair of second plate portions located at both ends of the first plate portion. A plurality of panel pieces may be randomly connected to extend from the heat transfer plate by surface-connecting the first plate part of another panel piece to the second plate part.

  The panel piece is composed of a first plate portion located in the center of the U-shape and a pair of second plate portions located at both ends of the first plate portion. A plurality of panel pieces may be connected in a mosaic pattern so as to extend from the heat transfer plate by surface-connecting the first plate part of another panel piece to the second plate part.

  According to the present invention, it is possible to provide a specific effect that it is possible to provide a cryopanel with improved exhaust speed and coagulation / adsorption efficiency.

  Hereinafter, embodiments to which the cryopanel of the present invention is applied will be described.

“Embodiment 1”
FIG. 1 is a diagram illustrating a structure of a cryopump in which the cryopanel of the first embodiment is used. The cryopump 1 includes a vacuum vessel 2, a refrigerator 3, a shield 4, and a cryopanel 10.

  The vacuum container 2 is a cup-shaped container having a circular cross section, and is connected to a process chamber (not shown) of a semiconductor manufacturing apparatus such as a sputtering apparatus or an ion implantation apparatus via the upper opening 2A. Inside the vacuum vessel 2, a cylinder (reference numerals 6 and 7), a shield 4, and a cryopanel 10 of the refrigerator 3 are disposed.

  The vacuum vessel 2 is connected with a roughing pump and a purge gas introduction pipe (both not shown), and a gate valve (not shown) is provided between the vacuum vessel 2 and the process chamber. Arranged.

  A compressor 5 is connected to the refrigerator 3.

  The compressor 5 boosts the refrigerant gas such as helium gas and sends it to the refrigerator 3, collects the refrigerant gas adiabatically expanded by the refrigerator 3, and pressurizes it again.

  The refrigerator 3 is a two-stage GM (Gifford-McMahon) type refrigerator, and includes a first-stage cylinder 6, a second-stage cylinder 7, and a motor (not shown). A first stage displacer 6A and a second stage displacer 7A connected to each other are built in the first stage cylinder 6 and the second stage cylinder 7, respectively, and are reciprocated in the vertical direction in the figure by a motor. Cold is generated due to adiabatic expansion.

  A first-stage refrigeration stage 8 </ b> A is brazed to the outer periphery of the first-stage cylinder 6. The shield 4 is held by the first refrigeration stage 8A.

  The shield 4 is a cup-shaped member having a circular cross section for protecting the cryopanel 10 from the radiant heat of the vacuum vessel 2, and a louver 9 is disposed in the upper opening. The louver 9 is disposed in the vicinity of the upper opening 2 </ b> A of the vacuum vessel 2. The shield 4 and the louver 9 are cooled to 30 to 100K by the first stage refrigeration stage 8A.

  The second stage refrigeration stage 8B is brazed to the outer periphery of the second stage cylinder 7. The cryopanel 10 is held by the second stage refrigeration stage 8B and cooled to the 10-20K level.

  Here, it is assumed that water molecules, argon, nitrogen, hydrogen, neon, and helium are present in the process chamber. When the shield 4 and the louver 9 are cooled to 30 to 100 K and the cryopanel 10 is cooled to the 10 to 20 K level, water molecules are mainly solidified by the shield 4 and the louver 9, and argon and nitrogen other than water molecules are mainly It is solidified by the cryopanel 10. Hydrogen, neon, helium, etc. are adsorbed mainly on an active layer (layered activated carbon, the same applies hereinafter) formed on the surface of the cryopanel 10. Thereby, the process chamber is evacuated and kept in a high vacuum.

  The gas in the process chamber flows into the vacuum vessel 2 through the upper opening 2A. Here, the gas inflow direction is a direction from the upper opening 2 </ b> A of the vacuum vessel 2 toward the bottom, and the gas flow path is formed in this direction. In this gas flow path, the upper opening 2A side is referred to as the upstream side, and the bottom side of the shield 4 is referred to as the downstream side. Further, the lateral outer side of the gas flow path is a side with respect to the gas inflow direction, and refers to the outer side of the vacuum vessel 2 (or the shield 4). These are common in all drawings.

  The cryopump shown in FIG. 1 is a so-called vertical cryopump in which the first stage refrigeration stage 8A and the second stage refrigeration stage 8B are inserted from below the vacuum vessel 2.

  2A and 2B are diagrams showing the cryopanel of the first embodiment, where FIG. 2A is a plan view seen from the upper opening 2A side of the vacuum vessel 2, FIG. 2B is a perspective view, and FIG. 2C is a panel piece. It is a perspective view shown.

  As shown in FIG. 2, the cryopanel 10 includes a heat transfer plate 11 and a panel portion 12. The heat transfer plate 11 is a plate-like support member bent so as to have a U-shaped cross section, and two holes 11a for screwing to the second stage refrigeration stage 8B are formed at the top. Has been.

  2 (a) and 2 (b) are obtained by connecting a plurality of panel pieces in a mosaic shape, and each panel piece 12A has a U-shaped cross section as shown in FIG. 2 (c). It is a plate-shaped member.

The panel piece 12A includes a first plate portion 12a located at the center of the U-shape and a pair of second plate portions 12b located at both ends of the first plate portion 12a. The two plate portions 12b are, for example, a copper plate having a thickness of 0.5 mm and a square surface having a length of 30 mm and a width of 30 mm.

  Such heat transfer plate 11 and panel portion 12 (panel piece 12A) are both made of copper and plated. An active layer is formed on the inner surface of the U-shape of the panel piece 12A. Here, the active layer is indicated by dots. The active layer is not formed on the heat transfer plate 11.

  Next, how to attach the panel piece 12A to the heat transfer plate 11 will be described. Since the panel piece 12A is attached symmetrically to the pair of side walls 11A of the heat transfer plate 11 in a plan view as viewed from the upper opening 2A, here, how to attach to the one side wall 11A will be described. Here, it is assumed that the panel pieces 12A are connected by soldering.

  Three panel pieces 12A are attached to the side wall 11A of the heat transfer plate 11 from the upstream side to the downstream side in the gas inflow direction. The panel piece 12 </ b> A located at the center of the three is attached such that the first plate portion 12 a is surface-connected to the side wall 11 </ b> A of the heat transfer plate 11. The panel piece 12A located on the upstream side and the downstream side of the panel piece 12A located at the center has the first plate portion 12a surface-connected to the second plate portion 12b of the center panel piece and the second plate. The part 12b is attached so as to be surface-connected to the side wall 11A of the heat transfer plate 11.

  That is, the central panel piece 12A is arranged so that the U-shape faces the outside of the gas flow path, and the upstream panel piece 12A has the U-shape facing the upstream direction of the gas flow path. The panel piece 12A on the downstream side is arranged so that the U-shape faces the downstream direction of the gas flow path.

  Further, the first plate portion 12a of another panel piece 12A is surface-connected to the second plate portion 12b of the upstream and downstream panel pieces 12A, respectively. That is, the panel piece 12A is arranged so that the U-shape faces the outside of the gas flow path.

  Furthermore, the first plate portion 12a of another panel piece 12A is surface-connected to the pair of second plate portions 12b of the panel piece 12A. The U-shape of the panel piece 12A is disposed so as to face the lateral outer side of the vacuum vessel 2 (and the shield 4).

  As described above, as shown in FIG. 2B, the panel portion 12 including the 18 panel pieces 12 </ b> A is attached to the heat transfer plate 11. All the panel pieces 12 </ b> A are arranged so that the U-shape is directed in any of the upstream direction, the lateral outer side, or the downstream direction of the gas flow path, and the mosaic is formed so as to extend from the heat transfer plate 11. Connected to each other.

  When evacuation is performed by a cryopump having such a cryopanel 10, the cryopanel 10 is cooled by the second-stage refrigeration stage 8B. That is, the cold generated by the second refrigeration stage 8B is conducted through the heat transfer plate 11, and each panel piece 12A is cooled to the 10-20K level. Then, it is solidified or adsorbed on the active layer formed on the panel piece 12A such as argon, nitrogen, hydrogen, neon, helium.

  Here, in the cryopanel 10, in a plan view as viewed from the upper opening 2 </ b> A of the vacuum vessel 2, a flow path is generally secured from the center side to the side close to the shield 4, and an active layer is formed. Has a sufficient surface area. For this reason, a flow path is not restrict | limited by the disk-shaped panel of a center part conventionally, and an active layer is not arrange | positioned in the shadow part of a panel.

  As described above, according to the cryopanel 10 of the present embodiment, the portion that is behind the gas flow path can be reduced, and the surface area of the panel portion 12 on which the active layer is formed can be sufficiently secured. Therefore, the exhaust speed can be improved as compared with the conventional cryopanel having a plate-like panel only on the downstream side of the disk-like panel. In addition, compared to a conventional conical panel, the U-shaped panel pieces 12A are connected in a mosaic shape, thereby ensuring a sufficient flow path from the upstream side to the downstream side of the gas flow path, The exhaust speed can be improved. In particular, the exhaust speed of hydrogen, neon, helium or the like that does not condense at the 10-20K level can be improved.

  Further, since the active layer is formed only inside the U-shape of the panel piece 12A, the active layer is disposed so as to surround the cryopanel 10 as compared with the case where the active layer is formed on both surfaces of the panel piece 12A. The influence of the radiant heat received from the shield 4 can be reduced.

  In the present embodiment, the panel piece 12A is a plate-like member bent into a U-shape, and the panel piece 12A constitutes the joined panel portion 12 in a mosaic shape. Manufacture is easy, and the manufacturing cost of the cryopanel can be significantly reduced.

  Further, in the above description, the active layer is formed on the inner surface of the U-shape of all the panel pieces 12A. However, the panel piece 12A disposed on the upstream side includes the active layer. May not be formed. Since the louver 9 connected to the shield 4 is disposed on the upstream side of the gas flow path of the cryopanel 10, the panel in which the active layer is not formed when the influence of radiant heat from the louver 9 side is large. By disposing the piece 12A on the upstream side, the influence of radiant heat can be reduced. In this case, the active layer may not be formed only on the surface facing the upstream side.

  In the above, the cryopanel 10 having the panel portion 12 in which 18 panel pieces 12A are joined in a mosaic shape as shown in FIG. 2 has been described. However, the shape of the panel portion 12 is not limited to the shape shown in FIG. Other shapes realized by randomly combining the U-shaped panel pieces 12A may be used.

  The number of panel pieces 12A included in each panel unit 12 may be changed according to the capacity of the process chamber to which the cryopump is connected and the type of process.

  Similarly to increasing or decreasing the number of panel pieces 12A included in each panel portion 12, a plurality of panel portions 12 may be arranged in the gas inflow direction according to the depth or internal shape of the vacuum vessel 2. In this case, the same effect can be obtained.

  Moreover, although the form which solders the panel piece 12A was demonstrated above, as shown in FIG. 3, a hole is formed in the center of the 1st board part 12a and the 2nd board part 12b, and panel pieces 12A are connected. It may be screwed.

  In the above description, the active layer is formed on the panel piece 12A. However, a sheet-like active layer may be attached to the front and back surfaces of the panel piece 12A.

“Embodiment 2”
4A and 4B are diagrams showing the configuration of the cryopanel of the second embodiment. FIG. 4A is a front view showing a panel portion and a mounting plate, and FIG. 4B is a perspective view showing the panel portion. The configuration of the cryopanel 20 according to the second embodiment conforms to the configuration of the cryopanel according to the first embodiment, and therefore the same or equivalent components are denoted by the same reference numerals and the description thereof is omitted.

  As shown in FIG. 4A, in the cryopanel 20 of the second embodiment, more panel pieces 12A are provided so as to extend outward from the heat transfer plate 11 than in the cryopanel 10 shown in FIG. It is different from the first embodiment in that it is attached. The cryopanel 20 includes 34 panel pieces 12A and is suitable when the diameter of the vacuum vessel 2 is large.

  Thus, also in the cryopanel 20 of the second embodiment, the portion behind the gas flow path can be reduced, and the surface area of the panel portion 12 on which the active layer is formed can be sufficiently secured. In addition, the exhaust speed can be improved compared to a cryopanel having a plate-like panel only on the downstream side of the disk-like panel. Compared to a conical panel as in the prior art, the U-shaped panel pieces 12A are connected in a mosaic pattern to ensure a sufficient flow path from the upstream side to the downstream side of the gas flow path. Can do. In particular, the exhaust speed of hydrogen, neon, helium or the like that does not condense at the 10-20K level can be improved.

  In the first and second embodiments, the cryopanel used in the vertical cryopump shown in FIG. 1 has been described. However, the cryopanel may be used in a horizontal cryopump in which a stage is introduced from the side into the vacuum vessel 2. . In the cryopanels of the first and second embodiments, since the panel portion 12 is not attached to the U-shaped side surface of the heat transfer plate 11, the second stage refrigeration stage introduced from the side into the vacuum vessel 2. The cryopanel can be attached to the second-stage refrigeration stage 8B without interference between 8B and the panel unit 12.

  Further, the change in the number of steps of the panel portion 12 in the gas inflow direction, the number of panel pieces arranged in the radial direction, or the connection pattern of the panels is not limited to the form shown here.

  In the above description, the members to be soldered may be joined by rivets and screwing, or may be joined by both soldering and screwing.

  The cryopanel of the exemplary embodiment of the present invention has been described above, but the present invention is not limited to the specifically disclosed embodiment, and does not depart from the scope of the claims. Various modifications and changes are possible.

It is a figure which shows the structure of the vertical cryopump in which the cryopanel of Embodiment 1 is used. It is a figure which shows the cryopanel of Embodiment 1, (a) is the top view seen from the upper opening side of a vacuum vessel, (b) is a perspective view, (c) is a perspective view which shows a panel piece. 6 is a perspective view showing a panel piece of a modification of the first embodiment. FIG. It is a figure which shows the structure of the cryopanel of Embodiment 2, (a) is a front view which shows a panel part and an attachment board, (b) is a perspective view which shows a panel part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cryopump 2 Vacuum container 3 Refrigerator 4 Shield 5 Compressor 6 First stage cylinder 6A First stage displacer 7 Second stage cylinder 7A Second stage displacer 8A First stage refrigeration stage 8B Second stage refrigeration stage 9 Louver 10, 20 Cryopanel 11 Heat transfer plate 11a Hole 12 Panel 12A Panel piece

Claims (6)

A vacuum vessel having a gas inlet, and a stage disposed in the vacuum vessel, and a refrigerator that cools the stage, and solidifies molecules flowing into the vacuum vessel from the gas inlet A cryopanel used for a cryopump to be adsorbed,
A heat transfer plate held and cooled by the stage;
A cryopanel, comprising: a panel portion supported by the heat transfer plate and disposed in a gas flow path in the vacuum vessel, the panel portion including a plurality of plate-shaped panel pieces having a U-shaped cross section.   2. The cryopanel according to claim 1, wherein the panel piece is a U-shaped panel piece in which a plate-like panel having a rectangular shape in plan view is uniformly bent in a longitudinal direction.   The cryopanel according to claim 1 or 2, wherein an active layer is formed or adhered to an inner surface of the U-shape of the panel piece.   The cryopanel according to claim 3, wherein the panel piece is disposed such that the U-shape is oriented in any direction of an upstream side, a lateral outer side, or a downstream side of the gas flow path. The panel piece is composed of a first plate portion located at the center of the U-shape and a pair of second plate portions located at both ends of the first plate portion,
A plurality of panel pieces are randomly connected to extend from the heat transfer plate by surface-connecting the first plate part of another panel piece to the second plate part of one panel piece. Item 5. The cryopanel according to item 4. The panel piece is composed of a first plate portion located at the center of the U-shape and a pair of second plate portions located at both ends of the first plate portion,
By connecting the first plate part of the other panel piece to the second plate part of one panel piece, a plurality of panel pieces are connected in a mosaic shape so as to extend from the heat transfer plate, The cryopanel according to claim 4.

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