JP2565155Y2 - Turbo molecular pump device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbo-molecular pump device which is applied to a semiconductor manufacturing apparatus or the like, and generates heat by applying a high voltage to a coil of an induction motor when a temperature of a predetermined position decreases.

[0002]

2. Description of the Related Art Conventionally, in a semiconductor manufacturing apparatus such as an etching apparatus and a CVD apparatus, a non-contact rotating turbo-molecular pump apparatus for magnetically levitating a rotor is used to form SiH ₄ and PH.
₃ , process gases such as B ₂ H ₆ and _AS H ₃ are discharged. It is known that a process gas flowing through a turbo molecular pump device of a semiconductor manufacturing apparatus generates a product when the temperature drops to 50 ° C. to 60 ° C., and this product adheres as a deposit to an adjacent inner wall or the like. ing.

If the operation is performed for a long time in this state, deposits on the rotor blades and the stator blades increase, and as a result, the turbo molecular pump device may not be operated. For this reason, the turbo-molecular pump device is provided with, for example, a heater and a control circuit for controlling the heat generation of the heater, and controls the energization of the heater so that the temperature of the turbo-molecular pump device does not decrease. I have.

[0004]

However, the turbo molecular pump device of the above-mentioned conventional example requires a heater, a control circuit, and the like, and has a drawback that the configuration is complicated. The present invention has been made in view of the above problems, and when the detected temperature is lower than a predetermined temperature, the coil of the induction motor generates heat to prevent the temperature from dropping, and occurs when the temperature of the process gas drops when used in a semiconductor manufacturing apparatus or the like. An object of the present invention is to provide an excellent turbo-molecular pump device capable of preventing the accumulation of products.

[0005]

In order to achieve the above object, a turbo-molecular pump device according to the present invention comprises at least a stator blade, a rotor having rotor blades, an induction motor for rotating the rotor, and a voltage applied to the induction motor. A turbo molecular pump device comprising: a power supply for supplying; and a temperature increasing unit, wherein the temperature increasing unit is provided with a temperature detecting unit that outputs a detected temperature signal that detects a temperature at a predetermined position, and the detected temperature signal is supplied. A comparison means for comparing the detected temperature with a set predetermined temperature and outputting a signal when the detected temperature is lower than the predetermined temperature; and when a signal is supplied, applying a high voltage from a power supply to a coil of the induction motor. And control means for performing control for application.

[0006]

In the turbo molecular pump device of the present invention configured as described above, the detected temperature is compared with the set predetermined temperature, and a high voltage is applied to the induction motor coil only when the detected temperature is lower than the predetermined temperature. The application control is performed. Thereby, when the detected temperature is lower than the predetermined temperature, the coil of the induction motor generates heat, and the temperature can be prevented from lowering.

[0007] When used in a semiconductor manufacturing apparatus or the like,
With a simple configuration in which only control for applying a high voltage to the induction motor is performed, it is possible to prevent the products generated by the reaction when the temperature of the process gas decreases from accumulating on the stator blades and the rotor blades.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of an embodiment of the turbo-molecular pump device of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows the overall configuration of the embodiment, which is installed in a semiconductor manufacturing apparatus or the like to discharge a process gas.

In this example, a plurality of stator blades 12 are arranged inside a cylindrical exterior body 10, and a plurality of rotor blades 14 are arranged between the respective stator blades 12. The rotor blade 14 is provided on an outer peripheral wall of the rotor 15 and rotates in conjunction with a rotor shaft 18 made of a magnetic material. The rotor 15 utilizes a so-called magnetic bearing. A pair of radial electromagnets 20 opposed to each other with the rotor shaft 18 interposed therebetween is arranged around the rotor shaft 18.
, A pair of radial sensors 22 facing each other across the rotor shaft 18 are provided.

Further, a pair of radial electromagnets 24 similar to the above are arranged, and a pair of radial sensors 26 are provided adjacent to the radial electromagnet 24 as well. An excitation current is supplied to the radial electromagnets 20 and 24 to cause the rotor shaft 18 to magnetically levitate, and the rotor shaft 18 is excited to be held at a predetermined position by a position detection signal of the radial sensors 22 and 26 during the floating. The current is controlled.

An induction motor 30 is provided between the radial direction sensor 22 and the radial direction sensor 26 inside the exterior body 10. When power is supplied to the induction motor 30, the rotor shaft 18, that is, the rotor blades 14 rotates. The rotor shaft 18 is provided with a disk-shaped metal disk 31 made of a magnetic material.
Further, a pair of axial electromagnets 32 and 34 facing each other are provided. Further, an axial sensor 36 is provided to face the cut end of the rotor shaft 18.

The exciting current of the axial electromagnets 32 and 34 is controlled by a position detection signal from an axial sensor 36 so as to hold the rotor shaft 18 at a predetermined position in the axial direction. At the end of the rotor shaft 18, a rotation sensor 38 for detecting the number of rotations of the rotor shaft is arranged. Further, a temperature sensor 50 such as a thermistor is provided near the exhaust port. These components are connected by cables to a signal processing system including a magnetic bearing controller, a main controller, and the like, via a connector 44 provided near the axial electromagnets 32 and 34.

Next, the electrical configuration and operation will be described. FIG. 2 shows the electrical configuration of FIG. This example is schematically constituted by a system controller 70 using a microprocessor (MPU) or the like and a magnetic levitation controller 80. This system controller 70
PU 70a, ROM 70b storing a program, working RAM 70c, keyboard interface (I
/ F) 70d, display I / F 70e, I / O 70f, 7
0g, 70h, and 70i, which are connected to the internal bus line 70j.

A keyboard 74 for performing various operations such as operation instructions is connected to the keyboard I / F 70d.
The display I / F 70e has an L state for displaying an operation state from the keyboard 74, a floating state, and an operation state.
A display 76 such as a CD is connected. The I / O 70f is connected to a magnetic levitation controller 80. The magnetic levitation controller 80 includes a pair of radial sensors 22, 2
6 and PIDs (correction circuits) 82a, 82b, 82c, 82 to which position detection signals from the axial sensor 36 are respectively input.
d and 82e are provided, and these PIDs 82a and 82e
Amplifiers 84a, 84b, 84c, 84d and 84e are connected to the respective output terminals of b, 82c, 82d and 82e.

The radial electromagnet 2 composed of a pair of coils is provided at the output of the amplifiers 84a, 84b, 84c and 84d.
0 and 24 are connected, and the output section of the amplification section 84e is connected to the axial electromagnets 32 and 34 each composed of a pair of coils. When the rotor shaft 18 magnetically levitates, the magnetic levitation controller 80 controls the radial sensors 22 and 2.
The amplifiers 84a and 84a hold the magnetically levitated rotor shaft 18 at a predetermined position based on the position detection signal from
Control is performed to change the excitation current supplied to the radial electromagnets 20 and 24 by changing the amplification factors b, 84c and 84d.

At the same time, the magnetic levitation controller 80
The amplification factor of the amplifier 84e is changed based on the position detection signal from the axial sensor 36 so as to keep the rotor shaft 18 at a predetermined position in the axial direction at the time of magnetic levitation.
Control is performed to change the excitation current supplied to 2, 34.
A rotation sensor 38 is connected to the I / O 70g,
The pulse signal from the rotation sensor 38 is read by the CPU 70a to detect the number of rotations of the rotor shaft 18,
O70h, I / O70i and temperature sensor 50 are connected to motor driver 77.

FIG. 3 shows the configuration of the motor driver 77 in detail. The motor driver 77, AC100V or the like from the AC power supply 90 is Ru is supplied to the rectifying and smoothing circuit 92. Here, the rectifying / smoothing circuit 92 includes a system
Motor driver from the I / O70i of the controller 70
Drive to which an operation / non-operation instruction signal of 77 is input
The circuit 100 is connected. The drive circuit 100
The rectification / smoothing circuit 92 is driven based on this instruction signal.
By control, the mode motor driver 77
Operation / non-operation is controlled. That is, the system
Motor driver 77 from the I / O70i of Torrox La 70
Is input to the drive circuit 100.
A from the AC power supply 90 supplied to the rectification / smoothing circuit 92
C1 00V etc. rectified, smoothed and input to the converter unit 93. In the converter unit 93, well-known switching is performed by a transistor or the like, and an AC output is supplied to the high-frequency transformer RT. The AC output insulated by the high-frequency transformer RT is supplied to a rectifier / smoothing circuit 94, rectified and smoothed, input to an inverter unit 95, converted into a three-phase AC voltage, and connected to the inverter unit 95. It is supplied to the coil of the induction motor 30 that has been set.

The motor driver 77 is provided with a temperature detection circuit 97 composed of an operational amplifier or the like to which an output signal from the temperature sensor 50 arranged near the exhaust port is input. Entered at the end. The other input end of the comparator 98 is connected to the I / O 70 h of the system controller 70, and a command value (threshold) corresponding to the temperature to be set is input from the keyboard 74.

The output signal of the comparator 98 is supplied to a drive circuit 99.
As described below, the voltage of the AC output supplied to the induction motor 30 is changed by this drive voltage.

In the above configuration, the temperature detecting means corresponds to the temperature sensor 50 and the temperature detecting circuit 97 , and the control means includes the system controller 70 and the drive circuit 99.
And the converter unit 93 corresponds. Next, the control operation of the above-mentioned temperature rise will be described. Under the control of the system controller 70, the radial electromagnets 20 and 24 and the axial electromagnets 32 and 34 are operated by energization control of the magnetic levitation controller 80, and the rotor shaft 18 is
It floats within 0 and is held in place. Furthermore, CPU
The control of 70a to the drive circuit 100 of the motor driver 77 through the I / O70 i instruction signal operation is input
The AC voltage from the AC power supply 90 as described above.
3 by the action of the flow-flat smooth circuit 92 to the inverter unit 95
It is converted to a phase AC voltage. Out of the inverter unit 95
The applied three-phase AC voltage (normal AC output voltage) is applied to the induction motor 30, and the rotor shaft 18 rotates. At the same time, the pulse signal I / O7 from the rotation sensor 38
The CPU 70a captures the data through 0g through polling, interrupt processing, etc., and performs well-known rotation control.

Here, the rotor blades 14 rotate to discharge a process gas in a semiconductor manufacturing apparatus or the like. At the same time, an output signal from the temperature sensor 50 that detects the temperature near the exhaust port is input to one input terminal of the comparator 98 through the temperature detection circuit 97. A command value (threshold) corresponding to the temperature set from the keyboard 74 is input to the other input terminal of the comparator 98 through the I / O 70h of the system controller 70, and the output signal from the temperature detection circuit 97 and the And outputs a signal obtained by comparing the command values.

The signal from the comparator 98 is output when the output signal from the temperature detecting circuit 97 is lower than the command value , that is, when the temperature near the exhaust port is lowered. 99 is input. Comparator 98
When the signal is input from the controller 93, the drive circuit 99 controls the ON time of the transistor in the converter unit 93 to be longer than usual. Then, alternating current having a higher voltage than usual is output from converter unit 93. This alternating current passes through a high-frequency transformer RT, a rectifying / smoothing circuit 94 and an inverter unit 95, and the high voltage V shown in FIG.
H is applied to the coil of the induction motor 30. When the temperature near the exhaust port rises, that is, when the value of the output signal supplied through the temperature sensor 50 and the temperature detection circuit 97 is higher than the command value , the output signal from the comparator 98 is output from the drive circuit. Not supplied to 99 .

Therefore, the drive circuit 99 controls the ON time of the transistor in the converter unit 93 so that it becomes normal, so that a normal AC output voltage is obtained from the converter unit 93 and the AC output voltage of this voltage is obtained. The voltage is applied as a low voltage VL to the coil of the induction motor 30 through the high frequency transformer RT, the rectifying / smoothing circuit 94 and the inverter unit 95 as shown in FIG.

As described above, the control of applying the high voltage VH or the low voltage VL to the coil of the induction motor 30 by the output signal of the temperature sensor 50 is performed. Only when the temperature detected by the temperature sensor 50 decreases, the motor driver 77 applies a higher voltage VH to the coil of the induction motor 30 than during normal rotation.

The heat generated by the application of the high voltage VH raises the temperature of the process gas passage and the like, and prevents the products resulting from the reaction of the process gas from accumulating on the rotor blades 14 and the stator blades 12 due to the temperature decrease. be able to. In addition,
In the above embodiment, the description has been given of the magnetic bearing type motor. However, the same operation and effect can be obtained by using a conventional three-phase induction motor.

[0026]

As is apparent from the above description, the turbo molecular pump device of the present invention compares the detected temperature with the set predetermined temperature, and when the detected temperature is lower than the predetermined temperature,
Since the control for supplying a high voltage to the coil of the induction motor is performed, there is an effect that the temperature of the coil of the induction motor can be prevented from lowering due to heat generation.

In addition, with a simple configuration in which only a control for applying a high voltage to the induction motor is performed, when a process gas used in a semiconductor manufacturing apparatus or the like has a reduced temperature, a product generated by a reaction when the temperature of the process gas is lowered is generated by a stator blade and a rotor blade. Etc. can be prevented.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a turbo-molecular pump device of the present invention.

FIG. 2 is a block diagram showing an electrical configuration of the embodiment.

FIG. 3 is a block diagram showing a detailed configuration of a motor driver shown in FIG. 2;

FIGS. 4A and 4B are diagrams of voltage waveforms applied to the operation of the embodiment and applied to the induction motor.

[Explanation of symbols]

 Reference Signs List 15 rotor 20, 24 radial electromagnet 30 induction motor 32, 34 axial electromagnet 50 temperature sensor 70 system controller 80 magnetic levitation controller 77 motor driver 92 rectification / smoothing circuit 93 converter section RT high-frequency transformer 94 rectification / smoothing circuit 95 inverter section 97 Temperature detection circuit 98 Comparator

Claims (1)

(57) [Scope of request for utility model registration] 1. A turbo-molecular pump device comprising at least a stator blade, a rotor having rotor blades, an induction motor for rotating the rotor, a power supply for supplying a voltage to the induction motor, and temperature increasing means. A temperature detecting unit that outputs a detected temperature signal that detects a temperature at a predetermined position; and the detected temperature signal is supplied. The detected temperature is compared with a set predetermined temperature to detect a detected temperature. A comparison means for outputting a signal when is lower than a predetermined temperature; and a control means for performing control for applying a high voltage from the power supply to the coil of the induction motor when the signal is supplied. A turbo molecular pump device characterized by the above-mentioned.