Vacuum pump

Abstract

To provide a vacuum pump which can be downsized without reducing exhaust performance and to provide a connection port used in the vacuum pump.SOLUTION: An exhaust port 14 which connects a vacuum pump 1 and an auxiliary pump comprises a first opening 14a which is oval in shape and can be connected to the vacuum pump 1 and a second opening 14b which is circular in shape and can be connected to the auxiliary pump. A diameter of the first opening 14a in an axial direction of the vacuum pump 1 is smaller than the diameter of the second opening 14b.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a vacuum pump and a connection port used for the vacuum pump.

Background Art

[0002] In the manufacture of semiconductor devices such as memories and integrated circuits, processes for forming insulating films, metal films, semiconductor films, etc. and processes for performing etching are carried out in a process chamber in a high-vacuum state in order to avoid the influence of dust in the air. For exhausting the process chamber, a vacuum pump such as a turbo molecular pump is used.

[0003] As such a vacuum pump, a turbo molecular mechanism having rotating blades and stationary blades arranged in multiple stages alternately in the axial direction is disposed in a casing having an intake port for inhaling gas from the outside and an exhaust port for exhausting the inhaled gas to the outside.

[0004] Patent Document 1 discloses a vacuum pump 1 configured to transfer the gas introduced through the intake port 4 downward in the axial direction by a gas transfer mechanism and exhaust the compressed gas to the outside through the exhaust port 6. Note that the reference numerals are those described in Patent Document 1.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the vacuum pump as described above, the exhaust port formed in a substantially cylindrical shape occupies a relatively large space, and there is a problem that the vacuum pump cannot be miniaturized in the axial direction.

[0007] In response to such a problem, it is conceivable to reduce the diameter of the exhaust port to create an excess space. However, even if the exhaust port is simply made smaller, the gas cannot be exhausted smoothly, and the exhaust performance of the vacuum pump is deteriorated.

[0008] Therefore, a technical challenge arises in order to miniaturize the vacuum pump without reducing exhaust performance, and the present invention aims to solve this problem. [Means for solving the problem]

[0009] To achieve the above objective, the vacuum pump according to the present invention is a vacuum pump that draws in or exhausts gas between itself and a connected external device, wherein the connection port connecting the external device and the vacuum pump comprises a non-circular first opening connectable to the vacuum pump and a circular second opening connectable to the external device, and the diameter of the first opening is set to be smaller than the diameter of the second opening in a direction perpendicular to the gas flow direction.

[0010] With this configuration, compared to conventional vacuum pumps using cylindrical connection ports, the first opening side of the connection port can be made smaller while maintaining the exhaust performance of the vacuum pump, thereby enabling miniaturization of the vacuum pump.

[0011] Furthermore, in order to achieve the above objective, it is preferable that the opening cross-sectional area of ​​the connection port perpendicular to the gas flow direction is set to be substantially the same from the first opening to the second opening in the vacuum pump according to the present invention.

[0012] With this configuration, compared to conventional vacuum pumps using cylindrical connection ports, the first opening side of the connection port can be made smaller while maintaining the exhaust performance of the vacuum pump, thereby enabling miniaturization of the vacuum pump.

[0013] Furthermore, in the vacuum pump according to the present invention, it is preferable that the first opening is formed in an oval shape and that its short axis substantially coincides with the axial direction of the vacuum pump.

[0014] This configuration allows the first opening side of the connection port to be molded to be smaller in the axial direction, thereby enabling the vacuum pump to be miniaturized in the axial direction.

[0015] Furthermore, it is preferable that the vacuum pump according to the present invention has a heater mounting portion in the connection port into which a heater for heating the connection port can be inserted.

[0016] This configuration allows the heater to raise the temperature of the connection port, thereby suppressing the accumulation of gas products within the connection port.

[0017] Furthermore, in the vacuum pump according to the present invention, it is preferable that the heater mounting portion is a cylindrical hole, and that its axial direction coincides with the long axis of the first opening.

[0018] With this configuration, the heater is mounted so as to traverse the connection port, allowing the connection port to be heated efficiently and further suppressing the accumulation of gas products within the connection port.

[0019] Furthermore, in the vacuum pump according to the present invention, it is preferable that the connection port is made of an aluminum alloy.

[0020] With this configuration, by forming the connection port with an aluminum alloy that has excellent thermal conductivity, the connection port is efficiently heated, and the accumulation of gas products within the connection port can be further suppressed.

[0021] Furthermore, in order to achieve the above objective, the connection port according to the present invention is a connection port for connecting a vacuum pump and external equipment and for circulating gas inside, comprising a first non-circular opening connectable to the vacuum pump and a second circular opening connectable to the external equipment, wherein the diameter of the first opening is set to be smaller than the diameter of the second opening in a direction perpendicular to the gas flow direction.

[0022] With this configuration, compared to conventional vacuum pumps using cylindrical connection ports, the first opening side of the connection port can be made smaller while maintaining the exhaust performance of the vacuum pump, thereby enabling miniaturization of the vacuum pump. [Effects of the Invention]

[0023] According to the vacuum pump of the invention, compared with the vacuum pump using a conventional cylindrical connection port, the first opening side of the connection port can be formed smaller while maintaining the exhaust performance of the vacuum pump, and the vacuum pump can be miniaturized.

[0024] Also, according to the connection port of the invention, compared with the vacuum pump using a conventional cylindrical connection port, the first opening side of the connection port can be formed smaller while maintaining the exhaust performance of the vacuum pump, and the vacuum pump can be miniaturized.

Brief Description of the Drawings

[0025]

FIG. 1

FIG. 2

FIG. 3

Mode for Carrying Out the Invention

[0026] Embodiments of the present invention will be described based on the drawings. In the following, when referring to the number of components, numerical values, amounts, ranges, etc., unless otherwise specified or limited to a specific number in principle, it is not limited to that specific number, and it may be more or less than the specific number.

[0027] Also, when referring to the shape, positional relationship of components, etc., unless otherwise specified or considered not to be so in principle, it includes those substantially approximate or similar to the shape, etc.

[0028] Also, the drawings may be exaggerated, such as enlarging characteristic parts for easy understanding of the characteristics, and the dimensional ratios of components are not necessarily the same as those in reality. Also, in sectional views, in order to make the sectional structure of components easy to understand, the hatching of some components may be omitted.

[0029] Figure 1 is a longitudinal cross-sectional view showing the vacuum pump 1. The vacuum pump 1 is a composite pump consisting of a turbomolecular pump mechanism PA and a screw groove pump mechanism PB, which are housed in a substantially cylindrical casing 10.

[0030] The vacuum pump 1 comprises a casing 10, a rotor 20 having a rotor shaft 21 rotatably supported within the casing 10, a motor 30 for rotationally driving the rotor shaft 21, and a stator column 40 housing a portion of the rotor shaft 21 and the motor 30.

[0031] The casing 10 consists of a base 11 and a cylindrical portion 13 that is fixed to the base 11 via bolts 12.

[0032] An exhaust port 14 is provided on the lower side of the base 11, which is connected to an auxiliary pump (not shown).

[0033] An air intake port 15 is formed at the upper end of the cylindrical portion 13, which is connected to a vacuum container such as a chamber (not shown). A flange 12b is formed on the outer circumference of the air intake port 15, which is connected to the vacuum container. An air intake port 16 is also provided on the side of the cylindrical portion 13, which is connected to the vacuum container. Hereafter, the exhaust port 14 and the intake port 16 will be collectively referred to as "connection ports".

[0034] The rotor 20 comprises a rotor shaft 21 and rotor blades 22 fixed to the upper part of the rotor shaft 21 and arranged concentrically with respect to the axis of the rotor shaft 21.

[0035] The rotor shaft 21 is non-contact supported by a magnetic bearing 50. The magnetic bearing 50 comprises a radial electromagnet 51 and an axial electromagnet 52. The radial electromagnet 51 and the axial electromagnet 52 are connected to a control unit 60.

[0036] The upper and lower parts of the rotor shaft 21 are inserted into the touchdown bearing 23. If the rotor shaft 21 becomes uncontrollable, the high-speed rotating rotor shaft 21 will come into contact with the touchdown bearing 23 to prevent damage to the vacuum pump 1.

[0037] The rotor blade 22 is integrally attached to the rotor shaft 21 by inserting the upper part of the rotor shaft 21 through the boss hole 24, and then inserting a bolt 25 through the rotor flange 26 and screwing it into the shaft flange 27.

[0038] The motor 30 consists of a rotor 31 attached to the outer circumference of the rotor shaft 21 and a stator 32 arranged to surround the rotor 31. The stator 32 is connected to a control unit 60, and the rotation of the rotor shaft 21 is controlled by the control unit 60.

[0039] The stator column 40 is mounted on the base 11, and its lower end is fixed to the base 11 via bolts 41.

[0040] The control unit 60 controls the excitation current of the radial electromagnet 51 and the axial electromagnet 52 based on the detection values ​​of a radial sensor (not shown) that detects the radial displacement of the rotor shaft 21 and an axial sensor (not shown) that detects the axial displacement of the rotor shaft 21, thereby supporting the rotor shaft 21 in a levitated state at a predetermined position.

[0041] Next, we will describe the turbomolecular pump mechanism PA, which is located in approximately the upper half of the vacuum pump 1.

[0042] The turbomolecular pump mechanism PA consists of a rotating blade 22 and a fixed blade 70 positioned with a gap between it and the rotating blade 22 in the axial direction. The rotating blade 22 and the fixed blade 70 are arranged alternately in multiple stages along the axial direction, and in this embodiment, five stages of rotating blade 22 and four stages of fixed blade 70 are arranged.

[0043] The rotor blades 22 consist of blades inclined at a predetermined angle and are integrally formed on the upper outer surface of the rotor 20. Multiple rotor blades 22 are also arranged radially around the axis of the rotor 20.

[0044] The fixed wing 70 consists of blades inclined in the opposite direction to the rotor blade 22, and is positioned by being sandwiched in the axial direction by spacers 71 that are stacked on the inner wall surface of the cylindrical section 13. In addition, multiple fixed wings 70 are installed radially around the axis of the rotor 20.

[0045] The turbomolecular pump mechanism PA described above is configured to transfer gas drawn in from the intake port 15 and intake port 16 from top to bottom in the axial direction by the rotation of the rotor blades 22.

[0046] Next, we will describe the screw-groove pump mechanism PB located in approximately the lower half of the vacuum pump 1.

[0047] The screw groove pump mechanism PB comprises a rotor cylindrical portion 28 provided at the lower part of the rotor 20 and extending along the axial direction, and a substantially cylindrical stator 80 arranged surrounding the outer circumferential surface 28a of the rotor cylindrical portion 28.

[0048] The stator 80 is mounted on the base 11. The stator 80 has screw grooves 81 engraved on its inner circumferential surface.

[0049] The screw-groove pump mechanism PB described above compresses the gas, which has been transferred axially downward from the intake port 15 and intake port 16, by the drag effect caused by the high-speed rotation of the rotor cylinder 28, and transfers it toward the exhaust port 14. Specifically, the gas is transferred into the gap between the rotor cylinder 28 and the stator 80, then compressed in the screw groove 81 and transferred to the exhaust port 14.

[0050] Next, the configuration of the connection ports will be explained using the exhaust port 14 as an example, based on Figures 2 and 3. Figure 2 is a perspective view showing the exhaust port 14. Figure 3(a) is a plan view of the exhaust port 14, Figure 3(b) is a cross-sectional view of line AA in Figure 3(a), and Figure 3(c) is a side view of the exhaust port 14.

[0051] The exhaust port 14 is formed in a cylindrical shape and allows gas to flow through it. The exhaust port 14 is made of, for example, an aluminum alloy with excellent thermal conductivity, which is cast into the pipe. The exhaust port 14 has a first non-circular opening 14a that is connected to the base 11 and a second circular opening 14b that is connected to the auxiliary pump. For convenience, the connection of the first opening 14a to the base 11 may be used to mean that the exhaust port 14 is connected to the vacuum pump 1.

[0052] The first opening 14a is formed in an oval shape with its minor axis set along the axial direction of the vacuum pump 1. Therefore, in the axial direction, the diameter dimension D1 of the first opening 14a is set to be smaller than the diameter dimension D2 of the second opening 14b. Note that the shape of the first opening 14a is not limited to the oval shape shown in the figure. For example, assuming a circle with an opening area corresponding to the required exhaust volume for the first opening 14a, the first opening 14a can be any shape, such as an ellipse, as long as it is smaller in the axial direction than this circle. Furthermore, the first opening 14a is not limited to an oval shape, but can also be a rectangle, a rhombus, or the like.

[0053] The exhaust port 14 has a cross-sectional area perpendicular to the gas exhaust direction from the first opening 14a to the second opening 14b, which is set to be approximately the same from the non-circular first opening 14a to the circular second opening 14b. As a result, compared to a conventional vacuum pump using a cylindrical exhaust port, the exhaust performance of the vacuum pump 1 using the non-cylindrical exhaust port 14 can be maintained while making the first opening 14a side of the exhaust port 14 smaller in the axial direction, thereby making the vacuum pump 1 smaller in the axial direction. The vertical cross-sectional area of ​​the exhaust port 14 may also be smoothly formed so as to gradually decrease or sequentially increase along the gas exhaust direction.

[0054] Furthermore, a heater mounting portion 14c is provided on the outer circumference of the exhaust port 14. Specifically, the heater mounting portion 14c is a cylindrical hole formed in a base 14d that bulges out from the outer circumference of the exhaust port 14, and is configured to allow insertion of a rod-shaped sheathed heater (not shown).

[0055] The sheathed heater, housed within the heater mounting section 14c, is fixed to the exhaust port 14 by bolts (not shown) inserted through bolt holes 14e. The sheathed heater raises the exhaust port 14 to a suitable temperature (e.g., 120°C) to suppress the accumulation of gas products within the exhaust port 14.

[0056] The heater mounting portion 14c is positioned so that its axial direction coincides with the long axis of the first opening 14a. This allows the sheathed heater to be mounted so as to traverse the exhaust port 14, thereby efficiently heating the exhaust port 14.

[0057] In Figure 2, reference numeral 14f indicates a sensor housing hole through which a temperature sensor (not shown) can be inserted. The temperature sensor is housed in the sensor housing hole 14c and fixed to the exhaust port 14 by a bolt (not shown) inserted through a bolt hole 14e. The temperature sensor sends the measured temperature of the exhaust port 14 to the control unit 60, which then controls the on / off state of the sheath heater to maintain a preset temperature.

[0058] Next, the configuration of the intake port 16 will be described. Note that the intake port 16 has almost the same configuration as the exhaust port 14, so redundant explanations will be omitted.

[0059] The intake port 16 has a different gas flow direction from the exhaust port 14 described above. Specifically, the intake port 16 has a non-circular first opening 16a corresponding to the first opening 14a that is connected to the casing 10, and a circular second opening 16b corresponding to the second opening 14b that is connected to a vacuum vessel (not shown). For convenience, the connection of the first opening 16a to the casing 10 may be used to mean that the intake port 16 is connected to the vacuum pump 1.

[0060] Furthermore, in the intake port 16, the cross-sectional area perpendicular to the gas flow direction from the second opening 16b to the first opening 16a is formed substantially the same along the gas flow direction, that is, from the circular second opening 16b to the non-circular first opening 16a. The vertical cross-sectional area of ​​the intake port 16 may also be smoothly formed to gradually decrease or sequentially increase along the gas flow direction.

[0061] Furthermore, the present invention can be modified in various ways as long as it does not depart from the spirit of the invention, and it goes without saying that the present invention extends to such modified forms.

[0062] The embodiments and variations of the present invention may be combined as needed.

[0063] Furthermore, although the configuration of the vacuum pump 1, which is equipped with an air intake port 15 and an air intake port 16, was described as an example in the above-described embodiment, the vacuum pump 1 may be equipped with only the air intake port 15 or the air intake port 16.

[0064] Furthermore, the connection port is not limited to one that directly connects the vacuum pump 1 and the external equipment; it may also be indirectly connected to the vacuum pump 1 and the external equipment via other piping or the like. [Explanation of Symbols]

[0065] 1. Vacuum pump 10 ···Casing 11 ···Bass 14. Exhaust port (connection port) 14a ···First opening (of the exhaust port) 14b ···Second opening (of the exhaust port) 14c ... Heater mounting section 14d ···Base 14e ···Bolt holes 14f ···Sensor housing hole 15 ···Air intake 16. Intake port (connection port) 16a ···First opening (of the intake port) 16b ···Second opening (of the intake port)

Claims

1. A vacuum pump that draws in or exhausts gas between a connected external device, the connection port connecting the external device and the vacuum pump includes a non-circular first opening connectable to the vacuum pump and a circular second opening connectable to the external device; A vacuum pump characterized in that the diameter of the first opening is set smaller than the diameter of the second opening in a direction perpendicular to the gas flow direction.

2. 2. The vacuum pump according to claim 1, wherein the cross-sectional area of ​​the opening of the connection port perpendicular to the gas flow direction is set to be substantially the same from the first opening to the second opening.

3. 3. The vacuum pump according to claim 1, wherein the first opening is formed in an oval shape, and the minor axis of the first opening is set so as to substantially coincide with the axial direction of the vacuum pump.

4. 4. The vacuum pump according to claim 3, wherein the connection port is provided with a heater mounting portion into which a heater for heating the connection port can be inserted.

5. 5. The vacuum pump according to claim 4, wherein the heater attachment portion is a cylindrical hole, and the axial direction of the heater attachment portion is aligned with the major axis of the first opening.

6. 6. The vacuum pump according to claim 1, wherein the connection port is made of an aluminum alloy.

7. A connection port for connecting a vacuum pump and an external device and circulating gas therein, a first opening having a non-circular shape and connectable to the vacuum pump, and a second opening having a circular shape and connectable to the external device; A connection port characterized in that the diameter of the first opening is set smaller than the diameter of the second opening in a direction perpendicular to the gas flow direction.

Images