JP3625657B2 - Liquid feed line pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid feed line pump suitable for use in transferring a special chemical solution such as a resist solution and a wafer protective film solution used when manufacturing a semiconductor device, for example.
[0002]
[Prior art]
Conventionally, as a liquid feeding device used for transferring the above-mentioned special chemical liquid, a positive displacement pump such as a piston type is installed in the middle of a liquid transfer line connecting a liquid supply source and a liquid supply destination. In general, those that are sent out while being compressed to a predetermined pressure are known.
[0003]
On the other hand, it is also widely performed to install an in-line pump in the middle of the liquid transfer line, in which the pump and the motor are integrated and can be easily attached in the middle of the piping. This type of in-line pump is provided with a main shaft that rotates integrally with the impeller as the motor rotates, and this main shaft is rotatably supported by a rolling bearing or a sliding bearing.
[0004]
[Problems to be solved by the invention]
However, the former using the conventional positive displacement pump has a problem that the liquid transfer is not continuously smooth because the piston type pump is arranged in the middle of the line piping. On the other hand, in the latter case using an in-line type pump, the contact of the sliding member at the rolling bearing or the sliding bearing is unavoidable, and this contact is accompanied by fine dust generation (particle generation). When such particles are mixed into the pumped liquid and mixed into the liquid transfer destination of the semiconductor device manufacturing equipment, the particles adhere to the semiconductor wafer manufactured using the chemical solution to be transferred, and the quality There was a problem that it would lead to a decline in
[0005]
Further, in a pump, a narrow gap (assembly gap) inevitably formed when the parts are assembled and assembled is generally present in the flow path of the pumped liquid. As a result, a stagnation region / dead water region is formed in the flow path of the pumped liquid, and the liquid enters the gap, which becomes rotted and contaminated with time. Then, when this liquid gradually oozes out into the pumped liquid, enters the pumped liquid of the pump, and enters the liquid transfer destination of a semiconductor device manufacturing facility or the like, a semiconductor manufactured using the chemical liquid to be transferred There is a problem that the contaminated liquid adheres to the wafer or the like and deteriorates its quality.
[0006]
In addition, the liquid accumulated in the stagnation region / dead water region in the flow path may solidify / adhere over time. In such a case, the flow path may be narrowed and blocked, which significantly deteriorates the pumping performance of the pump. For this reason, it will hinder the operation of the manufacturing apparatus or the like of the pumped liquid transfer destination. For this reason, maintenance is required, and such a pump becomes an impediment to production efficiency.
[0007]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a liquid feed line pump that can prevent contamination of a chemical solution to be transferred and has improved maintainability.
[0008]
[Means for Solving the Problems]
The invention according to claim 1 is an inline-type screw pump for transferring a liquid, wherein the rotor is supported in a radial direction by magnetic bearings provided at both ends of the rotor, and is attached to both end faces of the rotor. The rotor is supported in the axial direction by a control type magnetic bearing having a conical control surface provided opposite to the axial disk, and the rotor is magnetically levitated and supported in a non-contact manner by these both bearings. It is a liquid feed line pump which rotates without contacting and transfers liquid by a pump action by a screw groove provided on the outer periphery of the rotor.
[0009]
According to the present invention, since the rotor is supported by the magnetic bearings in the radial and axial directions in a non-contact manner, the rotor rotates without any contact with the stationary side, and is pumped by a screw groove provided on the outer periphery of the rotor. Liquid can be transferred. Thereby, unlike the pump using the conventional rolling bearing or the sliding bearing, the problem of dust generation (generation of particles) from the sliding portion can be prevented. Therefore, it is possible to prevent particles from being mixed into the pumped liquid and mixed into the manufacturing equipment of the semiconductor device to which the liquid is transferred.
[0010]
Then, a flow path extending substantially linearly in the axial direction is formed along the conical axial disk attached to both end faces of the rotor from the suction port and discharge port of the pump, and the pumped liquid is connected to the thread groove on the outer periphery of the rotor. As a result, the flow path of the pumped liquid becomes smooth and simplified. As a result, the stagnation region / dead water region of the pumped liquid is eliminated and the maintainability is improved.
[0011]
According to a second aspect of the present invention, the liquid contact portions on the rotor side and the stationary side of the pump are formed by forming a material having water repellency or a film of the material, and a stagnation region or a dead water region of the pumped liquid The liquid-feeding line pump according to claim 1, wherein
[0012]
As a result, a narrow assembly gap caused by the combination of the parts constituting the pump is covered with a coating of a material having water repellency. Accordingly, it is possible to prevent the liquid from penetrating into the narrow assembly gap and to eliminate the stagnation region / dead water region of the pumped liquid. Therefore, the liquid accumulated in the stagnation area and dead water area decays with time and becomes a pollutant, and this liquid gradually oozes into the pumped liquid and mixes into the pumped liquid. It is possible to prevent the liquid from being mixed into the apparatus to which the liquid is transferred. Further, since the stagnation region / dead water region in the flow path is eliminated, the liquid does not accumulate here, and the problem of solidification / adherence over time does not occur. Thereby, maintainability improves.
[0013]
According to a third aspect of the present invention, the suction port of the pump, the liquid transfer portion by the screw groove, and the discharge port of the pump are each arranged substantially linearly in the axial direction, and the screw groove The liquid transfer section is arranged along a gap between a conical axial disk surface attached to both end surfaces of the rotor and a control surface of a magnetic bearing provided opposite to the surface, and a suction port of the pump The liquid feed line pump according to claim 1, wherein the liquid feed line pump is connected to the discharge port in a substantially straight line in the axial direction. Thereby, the flow path of the pumping liquid can be formed so as to extend substantially linearly in the axial direction, so that the efficiency of the pump can be improved.
[0014]
According to a fourth aspect of the present invention, the rotor includes a cylindrical portion and conical axial disks provided on both end faces of the cylindrical portion, and a motor rotor is built in substantially the center of the cylindrical portion. 4. The liquid feeding device according to claim 1, wherein permanent magnets constituting a passive magnetic bearing are disposed at both ends of a screw groove on the outer periphery of the cylindrical portion. 5. It is a line pump. As a result, it is possible to provide a screw type pump in which the rotor is supported in a non-contact levitation manner by both the axial and radial magnetic bearings with a compact structure. In general, there is provided a liquid feed line pump which is free from the problem of contamination and has excellent maintainability.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same reference numerals indicate the same or corresponding parts.
[0016]
FIG.1 and FIG.2 shows the liquid feeding line pump of the 1st Embodiment of this invention. This pump is used, for example, when manufacturing a semiconductor device or the like, and is suitable for a transfer line for a special chemical solution such as a resist solution or a wafer protective film solution. That is, for example, it is used to send a chemically unstable special chemical solution from a transfer source tank or the like to a transfer destination semiconductor manufacturing apparatus or the like. A suction pipe (not shown) as a part of piping of the liquid transfer line is attached to the suction inlet 11 of the pump, and a discharge pipe (not shown) is similarly attached to the inner wall 12a of the discharge outlet 12. . Therefore, a suction pipe (not shown), this pump, and a discharge pipe (not shown) are arranged in a substantially straight line, and the liquid is sent in the axial direction by the rotation of the thread groove of the rotor inside the pump. It is a screw type pump.
[0017]
This screw type pump is mainly composed of a stator 20 and a rotor 30 having a thread groove on an outer peripheral portion. A can 23 is provided on the inner peripheral surface of the casing 21 at the center of the stator, and a motor stator chamber 22 is disposed. A motor stator 22b having a winding 22a is disposed in the motor stator chamber 22. In the motor stator 22b, a rotating magnetic field is formed by the current supplied to the winding 22a, and the motor rotor 32 disposed at a position facing the magnetic pole surface of the motor stator is driven to rotate, whereby the rotor 30 rotates.
[0018]
A screw groove 33 is provided on the outer periphery of the central portion of the rotor 30. When the rotor 30 is driven to rotate, the screw groove 33 also rotates, and the liquid existing in the space between the can 23 and the screw groove 33 is transferred. As a result, the liquid on the suction port 11 side is pumped to the discharge port 12 side.
[0019]
The stator 20 is provided with an uncontrolled radial magnetic bearing 15 that supports both ends of the rotor 30 on the casing 24, and thereby the rotor 30 is supported in a floating manner in the radial direction. In the radial magnetic bearing 15, the magnetic pole surfaces of the permanent magnet 15 a on the stator side and the permanent magnet 15 b on the rotor side face each other, and the rotor 30 is not contacted by the magnetic force acting between the magnetic pole surfaces. Is supported by levitation.
[0020]
An axial disk 35 made of a conical magnetic material is fixed to both end faces 30 a of the rotor 30. A control electromagnet 25 is disposed to apply a magnetic force to the axial disk 35. Similarly, the conical control surface 25a faces the conical surface 35a of the rotor-side axial disk 35 described above. The axial magnetic bearing 16 composed of the stator-side electromagnet 25 and the rotor-side axial disk 35 is a control type magnetic bearing, and the axially floating position of the rotor 30 so that the rotor 30 is positioned at the target floating position. Is controlled.
[0021]
That is, an axial sensor 26 is provided on the stator side to detect the axial displacement of the rotor 30. Then, a control current is formed by a compensation circuit (not shown), and this is supplied to the coil 25b of the electromagnet 25, thereby adjusting the magnetic force. As shown in the figure, in this pump, the axial magnetic bearings 16 are arranged on both the suction port 11 side and the discharge port 12 side. Thereby, the floating position in the axial direction of the rotor 30 is maintained at a constant target position regardless of the magnitude of the thrust force generated in the pump.
[0022]
A gap 16 between the magnetic pole surface 25a of the electromagnet 25 and the magnetic pole surface 35a of the axial disk facing the electromagnet 25 is a flow path for pumping liquid. That is, the liquid in the suction port 11 passes through the flow path 16, passes through the flow path 15 d provided in the gap 15 between the permanent magnets 15 a and 15 b constituting the radial magnetic bearing, and reaches the screw groove portion 33 of the rotor 30. The liquid is pumped by the pumping action of the rotating thread groove 33 here. Then, through the flow path 15d provided in the gap 15 between the permanent magnets 15a and 15b constituting the radial magnetic bearing, the gap between the magnetic pole face 25a of the electromagnet 25 and the magnetic pole face 35a of the axial disk opposite thereto is further provided. The discharge port 12 is reached through a certain flow path 16.
[0023]
Therefore, the rotor 30 of this pump is composed of a cylindrical portion and a conical axial disk 35 provided on both end faces 30a of the cylindrical portion. A motor rotor 32 is built in substantially the center of the cylindrical portion, and a screw groove portion 33 corresponding to a pump blade is disposed on the outer periphery of the rotor cylindrical portion. Permanent magnets 15b constituting a passive magnetic bearing are disposed at both ends of the rotor cylindrical portion. As a result, the rotor is supported in a non-contact levitation manner by both the axial and radial magnetic bearings, and the rotor having the thread groove on the outer periphery thereof can have a very compact structure.
[0024]
The suction port 11 of the pump, the liquid transfer part 33 by the thread groove, and the discharge port 12 of the pump are arranged substantially linearly in the axial direction. The liquid transfer portion 33 by the thread groove includes a surface 35a of a conical axial disk 35 attached to both end surfaces 30a of the rotor 30, and a control surface 25a of a magnetic bearing provided to face the surface 35a. As described above, it is connected to the suction port 11 and the discharge port 12 of the pump along the flow path 16 of the gap between them. As shown in the figure, the flow path 16 is formed in a substantially linear shape in the axial direction along a conical surface. As a result, the flow path of the pumped liquid in the pump can be formed so as to extend substantially linearly in the axial direction as a whole, so that the stagnation area / dead water area of the pumped liquid is reduced, and the efficiency of the pump can be improved.
[0025]
In this pump, the rotor-side and stationary-side liquid contact parts are formed by forming a water-repellent material or a film of the material. That is, as the material for the liquid contact portion, a fluororesin or the like is used, or a treatment such as applying a fluororesin coating, a fluororesin lining, or a fluororesin coating is performed. For example, a bulk member such as a rotor body is formed of a fluororesin, and a liquid contact surface of a metal material such as the can 23 or the permanent magnets 15a and 15b or a magnetic material is coated with the fluororesin. In addition, the storage portion in which the coil 25a of the control electromagnet 25 is arranged is sealed with an O-ring 27, and the liquid contact surface is filled with a fluororesin filler, and the entire magnetic pole surface is coated with the fluororesin. ing. The same applies to the sealing port of the axial sensor 26.
[0026]
By using a water-repellent material on the wetted surface, or by forming a film of the water-repellent material, the lift of special chemicals such as resist solution and wafer protective film solution can be used as a metallic material or magnetic material constituting the pump. No direct contact with materials. Thereby, it can prevent that the metal material and magnetic material which comprise a pump react with a special chemical | medical solution, and a pollutant elutes in a pumping liquid. Further, in this pump, there is a narrow gap that is inevitably formed by assembling the parts together, but the gap is covered by forming a film of a material having water repellency. Accordingly, it is possible to prevent liquid from permeating into the gap portion on the narrow assembly, and it is possible to eliminate the stagnation region / dead water region of the pumped liquid.
[0027]
The outline of the operation of this pump is as follows. The rotor 30 is levitated and supported in the radial direction by uncontrolled magnetic bearings 15 provided at both ends of the rotor. Then, by supplying an excitation current to the coil 25b of the electromagnet 25 having the conical control surface 25a provided opposite to the conical axial disk 35 attached to both end faces 30a of the rotor 30, the control type magnetic The rotor 30 is levitated and supported at a target position in the axial direction by the bearing 16. By supplying current to the coil 22a of the motor stator 22b while the rotor 30 is magnetically levitated and supported in a non-contact manner by the bearings 15 and 16, the rotor 30 incorporating the motor rotor 22 makes contact with the stationary side at all. Rotate without. Then, the liquid in the suction port 11 is pumped to the discharge port 12 side by the pumping action of the screw groove 33 provided on the outer periphery of the rotor 30.
[0028]
Thus, since the rotor 30 rotates without making any contact with the stationary side 20, the problem of dust generation (generation of particles) from the sliding portion can be prevented. Therefore, there is no problem that particles are mixed in the pumped liquid and the particles are mixed into the manufacturing equipment of the semiconductor device to which the liquid is transferred, and the quality thereof is hindered. Further, the pumping liquid flow path includes the pump suction port 11, the flow path 16 along the conical surface, the liquid transfer portion on the outer periphery of the rotor by the screw groove 33, and the flow along the conical surface again. It is connected to the discharge port 12 of the pump via the passage 16. Therefore, each is arranged substantially linearly in the axial direction. In addition, the liquid contact portions on the rotor side and the stationary side of the pump are configured by forming a water-repellent material such as a fluororesin or a film of the material.
[0029]
The flow path is arranged substantially linearly in the axial direction, and the narrow assembly gap in the pump is covered with a material having water repellency, thereby eliminating the stagnation area / dead water area of the pumped liquid. it can. Therefore, the liquid accumulated in the stagnation area / dead water area decays with time and becomes a pollutant, and this liquid gradually oozes out into the pumped liquid and mixes into the pumped liquid and enters the destination device. Can be prevented. Further, since the stagnation region and the dead water region in the flow path are eliminated, the liquid does not accumulate here, and the problem of solidification / adherence with the passage of time does not occur, so that the maintainability can be improved.
[0030]
Further, as shown in the figure, the pump of this embodiment has a symmetric suction port side and discharge port side, and the liquid is reversed by reversing the pump so that the discharge port and the suction port are reversed. Can be transferred in the direction. As a result, for example, when stopping the transfer of special chemicals such as resist solution or wafer protective film solution, the pump is reversely rotated to suck back the liquid so that the pump is almost empty and the pump is stopped. it can. Therefore, it can reduce that the chemical | medical solution which stayed in the pump at the time of a pump stop solidifies and adheres.
[0031]
3 to 8 show a liquid feed line pump according to a second embodiment of the present invention. The basic configuration of this pump is the same as that of the liquid feed line pump of the first embodiment shown in FIGS. That is, it is an inline screw pump suitable for transferring a special chemical solution such as a resist solution or a wafer protective film solution used for manufacturing a semiconductor device. Then, conical axial disks 35 and 40 attached to both end faces of the rotor 30 are provided, and the rotor 30 is moved in the axial direction by control-type magnetic bearings 25 and 25 having conical control surfaces provided opposite to the conical axial disks 35 and 40. To support. The permanent magnets 15b provided at both ends of the rotor 30 and the stator-side permanent magnets 15a provided on the outer peripheral side thereof constitute the magnetic bearing 15, and support the rotor 30 in the radial direction. . Then, the above-described liquid is pumped from the pump suction port 11 side to the pump discharge port 12 side in a substantially straight line by a pump action accompanying rotation of the rotor 30 by the screw grooves 33 and 41 provided on the outer periphery of the rotor or the inner periphery of the stator can. .
[0032]
Therefore, with the configuration of the magnetic bearings 15 and 25, the rotor 30 is magnetically levitated and rotates without any contact with the stationary side, so that dust generation caused by contact between the rotor and the stationary side can be completely suppressed. . This will not contaminate the pumped liquid. In addition, by using a flow path shape in which the flow of the pumped liquid flows only in the axial direction, the structure is an in-line type, and a water-repellent material such as a fluororesin or a coating thereof is used as the material of the liquid contact part constituting the pump In addition, it is possible to prevent the pumped liquid from permeating into a narrow assembly gap or the like generated by the combination of the parts, thereby eliminating the stagnation area and the dead water area of the pumped liquid.
[0033]
Here, the liquid feed line pump shown in FIG. 3 is provided with a screw groove 33 on the outer periphery of the rotor, like the liquid feed line pump shown in FIG. On the other hand, the liquid feed line pump shown in FIG. 4 is a modified embodiment in which a screw groove 41 is provided on the inner peripheral side of the stator can 23 instead of the screw groove 33 provided on the outer periphery of the rotor. Further, the liquid feed line pump shown in FIG. 5 shows a modified embodiment in which screw grooves 33 and 41 having opposite windings are provided on both the outer periphery of the rotor and the inner periphery of the can to improve the performance of the pump. ing.
[0034]
Further, the liquid feed line pump shown in FIGS. 3 to 5 is improved from the liquid feed line pump of the first embodiment shown in FIGS. 1 and 2 in the following points. First, as shown in FIG. 3A to FIG. 5A and FIG. 6, a flow path 42 is provided in the stator casing 24 on the outer peripheral side of the radial magnetic bearing 15. As a result, in the portion where the rotor 30 is supported by the radial magnetic bearing 15, it is possible to provide the flow path of the pumping liquid at substantially the same radial position as the thread groove surface on the outer periphery of the rotor. A flow path can be formed. In addition, by providing the flow path on the outer peripheral side of the radial magnetic bearing in which the permanent magnet 15a is disposed, the size of the flow path can be arbitrarily formed, thereby reducing the resistance loss of the pump.
[0035]
Second, as shown in FIG. 3 to FIG. 5 BB and FIG. 7, a flow path 43 is provided on the stator core 25 side of the axial magnetic bearing facing the axial disks 35 and 40 on the rotor side. Yes. Thereby, the flow path in an axial magnetic bearing part can be expanded, and reduction of resistance loss can be aimed at. Third, as shown in FIG. 3 to FIG. 5C and FIG. 8, the conical top portion of the axial disk 40 is flattened, and the axial displacement sensor 26a is disposed on the rotation axis facing this. Thus, a flow path 44 is provided outside the sensor. Thereby, the axial direction position of the rotor 30 can be easily detected by the axial sensor 26a, and the axial sensor 26a can be disposed in the casing 45 without hindering the formation of the linear flow path 44.
[0036]
【The invention's effect】
As described above, according to the present invention, there is provided a liquid feed line pump that has no problem of mixing particles or contaminants into the pumped liquid and is excellent in maintainability.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view along a main axis of a liquid feeding line pump according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
FIG. 3 is a sectional view taken along the main axis of a liquid feed line pump according to a second embodiment of the present invention.
4 is a cross-sectional view showing a modification of FIG.
5 is a cross-sectional view showing another modification of FIG. 3. FIG.
6 is a cross-sectional view taken along line AA in FIGS. 3 to 5. FIG.
7 is a cross-sectional view taken along the line BB in FIGS. 3 to 5. FIG.
8 is a cross-sectional view taken along the line CC of FIGS. 3 to 5. FIG.
[Explanation of symbols]
11 Suction port 12 Discharge port 15 Uncontrolled radial magnetic bearing (gap between magnetic pole faces of permanent magnet)
16 Control type axial magnetic bearing (gap between conical axial disk and pole face of electromagnet)
20 Stator 21, 24 Casing 22 Motor stator 23 Can 25 Electromagnet 25a Electromagnetic pole face 25b Coil 26, 26a Axial sensor 30 Rotor 30a Rotor end face 32 Motor rotor 33, 41 Screw groove 35 Conical axial disk 35a Magnetic pole faces 42, 43, 44 Flow path

Claims (4)

This is an inline screw pump that transfers liquid, and is supported by the magnetic bearings provided at both ends of the rotor in the radial direction, facing the conical axial disks attached to both end faces of the rotor. The rotor is supported in the axial direction by a control type magnetic bearing having a conical control surface, and the rotor is magnetically levitated and supported in a non-contact manner by these bearings, and rotates without contact with the stationary side. A liquid feed line pump characterized in that a liquid is transferred by a pump action by a screw groove provided on the outer periphery of a rotor. The liquid contact portion on the rotor side and the stationary side of the pump is formed by forming a water-repellent material or a film of the material, and excludes a stagnation region or a dead water region of the pumped liquid. Item 2. The liquid feed line pump according to Item 1. The suction port of the pump, the liquid transfer portion by the screw groove, and the discharge port of the pump are each arranged substantially linearly in the axial direction, and the liquid transfer portion by the screw groove is Along the gap between the conical axial disk surface attached to both end surfaces and the control surface of the magnetic bearing provided opposite to the surface, the suction port and the discharge port of the pump are substantially in the axial direction. The liquid feed line pump according to claim 1 or 2, wherein the liquid feed line pump is connected linearly. The rotor is composed of a cylindrical portion and conical axial disks provided on both end faces of the cylindrical portion. A motor rotor is built in substantially the center of the cylindrical portion, and the outer periphery of the cylindrical portion is The liquid feed line pump according to any one of claims 1 to 3, wherein permanent magnets constituting a passive magnetic bearing are disposed at both ends of the thread groove.

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