JP2007100629A - Turbo-molecular pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To expand application field of a turbo-molecular pump by preventing the vibration of an air cooling fan generated from the turbo-molecular pump having the air cooling fan. <P>SOLUTION: Drive power for P air cooling fan 5N or G air cooling fan 11N is supplied from P fan power source 14N or a G fan power source 13N via a P switch 21 or a G switch 22 respectively. The P air cooling fan 5N is stopped when the temperature of a P temperature sensor 8N does not exceed a predetermined threshold value and the G air cooling fan 11N is stopped when temperature of the C temperature sensor 10N does not exceed a predetermined threshold value, and the occurrence of vibration from each air cooling fan is prevented. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a turbo molecular pump used for generating a vacuum in a semiconductor manufacturing apparatus, a semiconductor inspection apparatus, an electron microscope, and other vacuum apparatuses for manufacturing / inspecting / researching using a vacuum.

  Turbomolecular pumps (hereinafter referred to as turbomolecular pumps or pumps) widely used in semiconductor manufacturing equipment, semiconductor testing equipment, electron microscopes and other vacuum equipment rotate the turbine blades to draw the gas sucked from the air intake. By continuously discharging to the outside atmosphere side, the pressure on the intake port side is reduced to generate a vacuum. A pump is generally composed of a pump unit that contains the turbine blades and the like and is directly connected to a vacuum apparatus, and a power supply unit that contains a pump drive power source and the like. The turbine blades are configured by alternately combining rotating blades (hereinafter referred to as moving blades) and stationary blades (hereinafter referred to as stationary blades) in multiple stages. The moving blade is generally rotated by a motor integrated with the moving blade and driven in a vacuum. In the rotating state, the heat from the motor is transmitted to the rotor blades, and there is also heat generated by the collision of various gases introduced into the vacuum device and the rotor blades to perform a predetermined operation, so the temperature of the entire rotor blade and pump unit rises. .

  In order to prevent the operation from being hindered by the temperature rise, the rotor blades are usually cooled by an air cooling method in which the pump unit is cooled by rotating an air cooling fan or a water cooling method in which a water-cooled snake pipe is wound around the outer wall of the pump unit and water is passed through the water-cooled snake pipe. And the method of suppressing the temperature rise of the whole pump unit is taken (refer patent document 1). In particular, the air-cooling method has been widely adopted in recent years because it does not require the provision of water-cooled pipes or protection measures against water leakage, and simplifies the use of the pump. The power supply unit of the turbo molecular pump needs to supply power of several hundred watts to maintain the rotational speed of the moving blade when the gas is introduced into the pump and the load on the moving blade is increased. Since the heat generated from the air also increases, an air cooling fan is often installed separately from the pump for cooling the power supply unit. There are turbo molecular pumps in which the pump unit and the power supply unit are separated from each other, and in which both are integrated.

  Hereinafter, the configuration and operation of a conventional turbomolecular pump will be described with reference to FIG. The pump includes a pump unit P directly connected to a vacuum device (not shown) and a power supply unit G that drives and controls the pump unit P. The rotor blade 1 is fixed to the rotating shaft 3 and is rotated together with the rotating shaft 3 by the motor 2. The gas molecules in the vacuum apparatus are compressed from the upper side to the lower side in FIG. The rotor blades 1 are assembled alternately with the stationary blades in the same manner as general turbine blades, but the illustration of the stationary blades is omitted in FIG. The rotating shaft 3 is levitated in a vacuum by a levitating electromagnet 4.

The pump unit P is cooled by a P air cooling fan 5. Position information during rotation of the moving blade 1 is detected by the displacement sensor 6, and an output controlled from the drive circuit 9 is fed back to the levitating electromagnet 4 via the CPU 12 in the power supply unit G, and a predetermined position is maintained. The rotation speed of the moving blade 1 is detected by the rotation sensor 7, and the output controlled from the drive circuit 9 is fed back to the motor 2 via the CPU 12 in the power supply unit G, so that the predetermined rotation speed is maintained. Driving power for the P air cooling fan 5 or the G air cooling fan 11 is supplied from the P fan power supply 14 or the G fan power supply 13. The temperature of the pump unit P or the power supply unit G is detected by the P temperature sensor 8 or the G temperature sensor 10, respectively. If an abnormal temperature is detected by the P temperature sensor 8 or the G temperature sensor 10, the pump unit P or the power supply unit G Stop operation.
JP 2001-132682 A

  The conventional cooling method of the moving blade of the turbo molecular pump is as described above. However, in this method, the pump vibrates due to the cooling, and the operation of the vacuum apparatus is obstructed. That is, vibrations of the turbo molecular pump are roughly classified into those generated by the rotation of the moving blade 1 and those generated from the P air cooling fan 5 and the G air cooling fan 11. The vibration generated by the rotation is a magnetic bearing. Most of the vibrations are generated from each of the above-described air cooling fans. In the conventional configuration, the P air cooling fan 5 and the G air cooling fan 11 of the pump unit P or the power supply unit G (hereinafter collectively referred to as each air cooling fan) are not included in the actual temperature of the pump unit P or the power supply unit G. Regardless, when the power supply unit G is energized, it always rotates at a basic rotational speed of around 60 rps, so each air cooling fan always generates vibrations of several tens to several hundred Hz corresponding to the basic rotational speed and its harmonic components. Was.

  Since the P air cooling fan 5 on the pump unit P side is directly connected to the pump unit P, the influence on the vacuum device is particularly large. For example, in the electron microscope, the resolution of the image is hindered by the vibration, and in the semiconductor manufacturing device, the nanometer. There has been an obstacle to the microfabrication. Therefore, in order to use a turbo molecular pump in a vacuum apparatus that may be damaged, it was necessary to confirm beforehand whether or not it could be adopted by preliminary experiments. As a result of prior confirmation, there were many cases that could not be adopted, and the sales channels for pumps were narrowed. In particular, in the pump in which the pump unit P and the power supply unit G are integrated, the G air cooling fan 11 on the power supply unit G side is also directly connected to the pump unit P, so that complicated vibrations including resonance and beat are generated from the two air cooling fans. And limited the application area of the pump. The object of the present invention is to provide means for solving such problems.

  In order to solve the above problems, a turbo molecular pump provided by the present invention comprises a pump unit and a power supply unit, and is provided with an air cooling fan for cooling the pump unit. A mechanism for stopping the air cooling fan is provided (claim 1).

  Further, in a turbo molecular pump comprising a pump unit and a power supply unit and provided with an air cooling fan for cooling the pump unit and a temperature sensor for detecting the temperature of the pump unit, the temperature measured by the temperature sensor during the steady operation of the turbo molecular pump. Is provided with a detection mechanism for detecting that the value is within a predetermined threshold, and a means for stopping the air-cooling fan in response to an output signal from the detection mechanism (claim 2).

  In addition, an air cooling fan 1 configured by a pump unit and a power supply unit and a temperature sensor 1 for detecting the temperature of the pump unit are provided, and the power supply unit includes a drive circuit for the motor and the electromagnet, and an air cooling fan 1. In a turbo molecular pump having a temperature sensor 2 for detecting the temperature of the power supply and the power supply unit and an air cooling fan 2 for cooling the power supply unit, the measured temperature of the temperature sensors 1 and 2 is within a predetermined threshold value during the steady operation of the molecular pump. A detection mechanism for detecting the presence of the air-cooling fan, and an air cooling fan 1 when the temperature measured by the temperature sensor 1 does not exceed a predetermined threshold value in response to an output signal from the detection mechanism, and the temperature measured by the temperature sensor 2 Is provided with means for stopping the air-cooling fan 2 when it does not exceed a predetermined threshold value (Claim 3).

  Further, the turbo molecular pump according to claim 2 is provided with means for decelerating the air cooling fan when the temperature measured by the temperature sensor does not exceed a predetermined threshold (claim 4).

  In the turbo molecular pump according to claim 3, when the measured temperature of the temperature sensor 1 does not exceed a predetermined threshold, the air cooling fan 1 is set, and the measured temperature of the temperature sensor 2 is set to a predetermined threshold. A means is provided for decelerating the air cooling fan 2 if it does not exceed (Claim 5).

  Since the temperature rise of the pump unit and the power supply unit is limited for most of the period during the steady operation of the turbo molecular pump, the turbo molecular pump is used for the most part during the steady operation of the turbo molecular pump. All or most of the vibration generated from the can be removed.

  Further, the turbo molecular pump according to any one of claims 1 to 5 can be provided with means for inputting a signal for constantly rotating the air cooling fans at a rated speed from outside (claim 6). In this way, when there is no need to reduce vibration, each air cooling fan can be rated and the temperature rise of the turbo molecular pump can be suppressed to the maximum.

  Furthermore, the turbo molecular pump according to any one of claims 1 to 6 can be provided with means for supplying an external device with an external output corresponding to the rotational state of each air cooling fan (claim 7). . In this way, it is possible to display the vibration state of the turbo molecular pump on the external device side such as a vacuum device, or to control the availability of external work where vibration is an obstacle.

  According to the present invention, the vibration can be reduced to zero or greatly over most of the operation time of the turbo molecular pump, and the applicable field of the turbo molecular pump can be expanded.

  Therefore, the basic configuration of the best mode is composed of a pump unit and a power supply unit, and the pump unit includes turbine blades composed of rotor blades and stationary blades, and a magnetic bearing that keeps the rotor blades in a predetermined position. An electromagnet, a motor for rotating the rotor blade, an attitude sensor for detecting the attitude of the rotor blade, a rotation sensor for detecting the rotational speed of the rotor blade, an air cooling fan 1 for cooling the pump unit, and a temperature for detecting the temperature of the pump unit A turbo molecular pump having a sensor 1 and a power supply unit including a drive circuit for the motor and the electromagnet, a power supply for the air cooling fan 1, a temperature sensor 2 for detecting the temperature of the power supply unit, and an air cooling fan 2 for cooling the power supply unit In the normal operation of the turbo molecular pump and the measured temperature of the temperature sensor 1 is within a predetermined threshold value A detection mechanism for detecting the presence, a means for stopping the air-cooling fan 1 by an output signal from the detection mechanism, a detection mechanism for detecting that the measured temperature of the temperature sensor 2 is within a predetermined threshold; This is a turbo molecular pump provided with means for stopping the air cooling fan 2 by an output signal from the detection mechanism.

  This will be described with reference to the illustrated example. FIG. 1A is a diagram showing the configuration of the pump of the present invention. The pump includes a pump unit PN and a power supply unit GN that drives and controls the pump unit PN. The moving blade 1N is fixed to the rotating shaft 3N and is rotated together with the rotating shaft 3N by the motor 2N. The gas molecules in the vacuum device (not shown) are compressed from the upper side to the lower side in FIG. In addition, the moving blade 1N is assembled with the stationary blades alternately like the general turbine blades, but the illustration of the stationary blades is omitted in FIG. The rotating shaft 3N is levitated in a vacuum by a levitating electromagnet 4N.

  The pump unit PN is cooled by a P air cooling fan 5N. Position information during rotation of the moving blade 1N is detected by the displacement sensor 6N, and the output controlled from the drive circuit 9N is fed back to the levitating electromagnet 4N via the CPU 12N in the power supply unit GN, and a predetermined position is maintained. The rotation speed of the moving blade 1N is detected by the rotation sensor 7N, and the output controlled from the drive circuit 9N is fed back to the motor 2N via the CPU 12N in the power supply unit GN, so that the predetermined rotation speed is maintained. Driving power of the P air cooling fan 5N or the G air cooling fan 11N is supplied from the P fan power supply 14N or the G fan power supply 13N via the P switch 21 or the G switch 22, respectively. The temperature of the pump unit PN or the power supply unit GN is detected by the P temperature sensor 8N or the G temperature sensor 10N, respectively. When an abnormal temperature is detected, the operation of the pump unit PN or the power supply unit GN is stopped. Further, when the temperature of the P temperature sensor 8N is lower than the abnormal temperature and does not exceed the predetermined threshold value, the P air cooling fan 5N is selected. When the temperature of the G temperature sensor 10N does not exceed the predetermined threshold value, G is selected. The air cooling fan 11N is stopped. The threshold is set between the normal temperature and the abnormal temperature, for example, around 55 ° C. for the P temperature sensor 8N, and around 65 ° C. for the G temperature sensor 10N.

  FIG. 1B is a detailed view of the P switch 21 and G switch 22 portions. Hereinafter, the P switch 21 and the G switch 22 are collectively referred to as each switch. In the figure, the positions of the P switch 21 and the G switch 22 indicate the case where the temperatures of the P temperature sensor 8N and the G temperature sensor 10N exceed the respective threshold values. Each switch is in the position shown in the figure by a control signal from the CPU 12N, and power from the P fan power supply 14N or G fan power supply 13N is sent to the P air cooling fan 5N or G air cooling fan 11N via the P switch 21 or G switch 22. Connected and rotating each fan. When the temperature of the P temperature sensor 8N is equal to or lower than the threshold value, the P switch 21 is switched in the opposite direction to the figure and the P air cooling fan 5N is stopped. Further, when the temperature of the G temperature sensor 10N is equal to or lower than the threshold value, the G switch 22 is switched in the opposite direction to the figure, and the G air cooling fan 11N is stopped.

  By stopping the P air cooling fan 5N, vibration generated from the P air cooling fan 5N in the pump unit PN can be prevented. Further, by stopping the G air cooling fan 11N, it is possible to prevent the vibration generated from the power supply unit GN from being transmitted to the vacuum apparatus. FIG. 1 shows a case where the pump unit PN and the power supply unit GN are separately provided. However, it is obvious that the present invention can be applied to a pump in which the pump unit PN and the power supply unit GN are integrated. The vibration of the pump unit PN is directly prevented by stopping the fan 11N.

  FIG. 2 is a diagram showing the switching of the P air cooling fan 5N as an operation sequence. Whether or not the temperature of the P temperature sensor 8N exceeds the threshold value is automatically checked periodically and repeatedly in an operation sequence starting from a position indicated as “start” in the figure. If it is determined in S21 that the threshold value is not more than the threshold value, the operation sequence flows downward along the Yes line in the figure, and the P air cooling fan 5N stops in S22. If the threshold value is exceeded in S21, the P air cooling fan 5N starts operation in S23 according to the No line in the figure. The operation sequence ends at the end of the figure, but the test is repeatedly performed from the start every period determined as described above. 2 illustrates the operation sequence of the P temperature sensor 8N and the P air cooling fan 5N, but the operation sequence is also obtained when the P temperature sensor 8N and the P air cooling fan 5N are replaced with the G temperature sensor 10N and the G air cooling fan 11N. Are similar to each other, and illustration and detailed description of the G temperature sensor 10N and the G air cooling fan 11N are omitted.

  The present invention is not limited to the above-described embodiments, and various modifications can be given. For example, a turbo-molecular pump that stops each air cooling fan by manual operation is also included in the present invention (corresponding to claim 1). As described above, the present invention is also applied to a pump in which the pump unit PN and the power supply unit GN are integrated. In addition, the operation sequence diagram of FIG. 3 is operated by two temperature values of threshold value 1 and threshold value 2 (threshold value 1 <threshold value 2, for example, threshold value 1 is 55 ° C. and threshold value 2 is 65 ° C. for the pump unit). FIG. 3 shows an operation sequence when the P air-cooling fan 5N is decelerated and controlled. In this case, as shown in FIG. 3, it is first tested whether or not the threshold value is 1 or less in S31 from the start. In this case, the P air cooling fan 5N is operated at 1/2 of the rated speed at S33 along the Yes line. If the threshold value is equal to or greater than 1 in S31, the test is continued to determine whether the threshold value is equal to or greater than 2 in S32. If the threshold value is equal to or less than 2, the P air cooling fan 5N is operated at 2/3 of the rated speed in S34. In this case, the P air cooling fan 5N is operated at the rated rotational speed in S35.

  The present invention can also be applied to such deceleration control. The values such as 1/2 of the rated speed and 2/3 of the rated speed are specified for explanation, and the range of deceleration can be arbitrarily set from zero to the rated speed. Also in FIG. 3, the flow is similar when the P temperature sensor 8N and the P air cooling fan 5N are read as the G temperature sensor 10N and the G air cooling fan 11N, as in FIG. 2, and therefore the G temperature sensor 10N and the G air cooling fan 11N are similar. The illustration and detailed description thereof are omitted.

  FIG. 4A further shows an operation sequence in the case where a test is first performed to determine whether or not vibration reduction is necessary. In this case, if it is not necessary to reduce the vibration in S41, the operation sequence proceeds to the right along the No line, and the P air cooling fan 5N is operated at the rated rotational speed. If it is necessary to reduce vibrations in S41, the process proceeds to the verification of threshold values 1 and 2, and the P air cooling fan 5N is decelerated. Note that the verification of threshold values 1 and 2 and the subsequent flow are the same as those in FIG. Also in FIG. 4A, the flow is similar when the P temperature sensor 8N and the P air cooling fan 5N are replaced with the G temperature sensor 10N and the G air cooling fan 11N as in FIG. The illustration and detailed description of the fan 11N are omitted. FIG. 4B shows an input example of a test for determining whether or not vibration reduction is necessary. For example, if it is not necessary to reduce vibration due to the operator's judgment, the vibration reduction unnecessary signal V is input to the CPU 12N from the outside, and the P air cooling fan 5N and the G air cooling fan 11N are always rated-rotated via the CPU 12N. The P switch 21 and the G switch 22 are fixed at the positions.

  As described above, the present invention is not limited to the number of threshold values. Therefore, it is possible to configure the operation sequence by applying the present invention so that the threshold number is increased as necessary, and each air cooling fan is stopped or decelerated depending on the temperature region. In addition, depending on the stop or deceleration status of each air cooling fan, the stage is displayed on the outside as a signal of the vibration status of the external vacuum device, or an output signal is provided for use as a control signal for external work that dislikes vibration Also good. That is, as shown in FIG. 5, the G air cooling fan 11N is driven by the output of the G fan power supply 13N, and at the same time, using this output, the G vibration provided on the external panel 23 of the external vacuum device (not shown). The display lamp 24 is turned on to output an external control signal C supplied to the external device, and the P vibration display lamp 25 provided on the external panel 23 is turned on to output the external control signal D supplied to the external device. Conceivable. The present invention includes all the above-described modified embodiments.

  The present invention can be applied to a semiconductor manufacturing apparatus, a semiconductor inspection apparatus, an electron microscope, and other uses necessary for generating a vacuum in a vacuum apparatus for manufacturing, inspection, and research using a vacuum.

It is a block diagram of the Example of this invention. It is an example of the operation | movement sequence diagram of this invention. It is another example of the operation | movement sequence diagram of this invention. It is another example of the operation | movement sequence diagram of this invention. It is a figure which shows one structural example for supplying an external output to an external device of this invention. It is a block diagram of the conventional turbo-molecular pump.

Explanation of symbols

1, 1N blade 2, 2N motor 3, 3N rotating shaft 4, 4N levitation electromagnet 5, 5N P air-cooled fan 6, 6N displacement sensor 7, 7N rotation sensor 8, 8NP temperature sensor 9, 9N drive circuit 10, 10N G Temperature sensor 11, 11N G air cooling fan 12, 12N CPU
13, 13N G fan power supply 14, 14N P fan power supply 21 P switch 22 G switch 23 External panel 24 G vibration display lamp 25 P vibration display lamp C, D External control signal G Power supply unit GN Power supply unit P Pump unit PN Pump unit V Low vibration unnecessary signal

Claims (7)

  A turbo molecular pump comprising a pump unit and a power supply unit and provided with an air cooling fan for cooling the pump unit, wherein the turbo molecular pump is provided with a mechanism for stopping the air cooling fan during steady operation of the turbo molecular pump. .   In a turbo molecular pump comprising a pump unit and a power supply unit and having an air cooling fan for cooling the pump unit and a temperature sensor for detecting the temperature of the pump unit, the temperature measured during the steady operation of the turbo molecular pump is previously measured. A turbo-molecular pump comprising: a detection mechanism for detecting that it is within a predetermined threshold; and means for stopping an air cooling fan in response to an output signal from the detection mechanism.   An air-cooling fan 1 that cools the pump unit and a temperature sensor 1 that detects the temperature of the pump unit are provided, and the power unit includes a drive circuit for the motor and the electromagnet, and a power source for the air-cooling fan 1. In the turbo molecular pump having the temperature sensor 2 for detecting the temperature of the power supply unit and the air cooling fan 2 for cooling the power supply unit, the measured temperature of the temperature sensors 1 and 2 is within a predetermined threshold value during the steady operation of the molecular pump. A detection mechanism for detecting the presence of the air cooling fan 1 when the temperature measured by the temperature sensor 1 does not exceed a predetermined threshold in response to an output signal from the detection mechanism and the temperature measured by the temperature sensor 2 A turbo molecular pump characterized in that means for stopping the air cooling fan 2 is provided when a predetermined threshold value is not exceeded.   3. The turbo molecular pump according to claim 2, further comprising means for decelerating the air cooling fan when the temperature measured by the temperature sensor does not exceed a predetermined threshold value.   Means are provided for decelerating the air cooling fan 1 when the measured temperature of the temperature sensor 1 does not exceed a predetermined threshold, and for decelerating the air cooling fan 2 when the measured temperature of the temperature sensor 2 does not exceed a predetermined threshold. The turbo-molecular pump according to claim 3.   6. The turbo molecular pump according to claim 1, further comprising means for inputting a signal for constantly rotating the air cooling fans at a rated speed from the outside.   7. The turbo molecular pump according to claim 1, further comprising means for supplying an external output corresponding to a rotational state of each air cooling fan to an external device.

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