JP3739628B2 - Scroll fluid machine that can be used in semiconductor production lines - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a semiconductor production line in which a reaction chamber in which a semiconductor wafer is placed is decompressed and a reaction gas is introduced into the reaction chamber to perform chemical treatment.Used forThe present invention relates to a usable scroll fluid machine.
[0002]
[Prior art]
  Conventionally, a semiconductor wafer is placed in a quartz reaction tube, the inside of the quartz reaction tube is sucked into a vacuum by a vacuum pump, and then a reaction gas is introduced from a gas supply source to form an insulating film or a metal film on the surface of the semiconductor wafer. Semiconductor manufacturing methods for deposition are known.
  However, the main gas used in this process is flammable SiH.₄, SiH₂CL₂Explosive H₂, NH₃, CO, toxic SiH₄, NH₃, CO, HCL, SiCL₄Corrosive NH₃Since these gases cause problems when these gases leak out of the semiconductor manufacturing apparatus, the reaction gas is discharged to the discharged fluid processing apparatus and detoxified at the end of each step.
[0003]
[Problems to be solved by the invention]
  However, the vacuum pump should be inherently airtight by the dynamic seal member between the sealed compression chamber that takes in and compresses the gas in the quartz reaction tube and the drive portion that compresses and drives the sealed compression chamber. However, when the dynamic seal member deteriorates, the sealed state becomes incomplete, and when the sealed compression chamber is finally compressed, the internal pressure becomes maximum and the reaction gas is driven from the sealed compression chamber by the differential pressure with the drive part. There is a risk of leakage.
[0004]
  In addition, a bearing having grease is disposed in the drive portion, and a structure that prevents the leakage of grease by a dynamic seal member is used. However, fine floating substances are used due to deterioration of the grease and contact between metal portions of the bearing. Is generated, solidifies and becomes large, abuts against the bearing and the dynamic seal member, and decreases the durability of these members.
[0005]
  Therefore, it is desirable to eliminate the reaction gas leaked to the drive part and the fine suspended matter generated from the bearing part as impurities during the semiconductor manufacturing process.
[0006]
  In view of the shortcomings of the prior art, the present invention generates a pressure in a semiconductor manufacturing line in which a reaction chamber in which a semiconductor wafer is placed is depressurized and a reaction gas is introduced into the reaction chamber for chemical processing. Semiconductor manufacturing line that eliminates impuritiesToIt is to provide a scroll fluid machine that can be used.
[0007]
[Means for Solving the Problems]
  Summary of the present inventionIn a scroll fluid machine having a fixed scroll and an orbiting scroll, the orbiting scroll wrap orbits and revolves with respect to the fixed scroll wrap by a rotary drive shaft having an eccentric portion that comes into contact with the center portion of the orbiting scroll end plate. ,
  The rotary drive shaft is formed such that a gas body is introduced from the outside so that the gas body can be discharged,
  The gas body can be supplied to a bearing provided between the orbiting scroll and the rotary drive shaft facing the rotary drive shaft,
  The gas body cools the scroll mechanism and discharges impurities around the bearing.
[0008]
  According to such a technique, a gas body different from the reaction gas is introduced into the sliding portion between the driving member and the counterpart member that slide against each other in the decompression means, and the introduced gas body causes the sliding portion to move from the sliding portion. Since the generated fine floating matter is discharged, the durability of the sliding portion is improved and the scroll mechanism can be cooled.
[0009]
  And this 1st invention isA gas body passage for introducing the gas body from one of the rotation drive shafts and discharging the gas body from the other is formed along the extending direction of the rotation drive shaft, and from the gas body passage to the bearing. Form a branch passage,
  A supply control means for controlling supply of a gas body from the outside to the gas body passage; and an exclusion control means for removing the gas body from the gas body passage;
  After the gas body is introduced by the supply control means, the supply control means is stopped until the operation of the exclusion control means is stopped.The
[0010]
  According to this technical means, a supply control means for controlling supply of a gas body from the outside to the gas body passage and an exclusion control means for removing the gas body from the gas body passage are provided, and the gas is controlled by the supply control means. After the body is introduced, the supply control means is stopped until the operation of the exclusion control means is stopped. Therefore, the supply control means and the exclusion control means are not excluded during the supply of the gas body. Since this is performed alternately, the gas body can be infiltrated to the back of the bearing portion, and fine floating matter at the back can be eliminated.
[0013]
  Also,The second inventionComprises a double wrap type orbiting scroll and fixed scrolls arranged on both sides facing the mirror surface of the orbiting scroll, and has an eccentric portion that abuts against the central portion of the orbiting scroll end plate. In the scroll fluid machine of the type in which the orbiting scroll wrap orbits with respect to the fixed scroll lap by the drive shaft,
  A bearing and a seal member provided between the orbiting scroll and the fixed scroll and the rotary drive shaft facing the rotary drive shaft;
  A gas body passage for introducing a gas body from one of the rotation drive shafts and discharging the gas body from the other is formed along the extending direction of the rotation drive shaft, and a branch passage is formed from the gas body passage. The gas body can be supplied to the bearing and the seal member,
  A supply control means for controlling supply of a gas body from the outside to the gas body passage; and an exclusion control means for removing the gas body from the gas body passage;
  After the gas body is introduced by the supply control means, the supply control means is stopped until the operation of the exclusion control means is stopped.
[0014]
  According to such a technique, since it is a double wrap type scroll machine, a large amount of fluid is taken in, and when used as a vacuum pump, a predetermined vacuum level can be reached quickly.
  Further, since the gas body passage for introducing the gas body from one of the rotary drive shafts and discharging the gas body from the other is formed along the extending direction of the rotary drive shaft, the scroll mechanism is cooled. be able to.
  Further, a branch passage is formed from the gas body passage so that the gas body can be supplied to the bearing and the seal member, so that the fine suspended matter generated from the sliding portion is discharged by the introduced gas body. Thus, durability of the sliding portion and the seal member is improved.
  Then, after the gas body is introduced by the supply control means, the supply control means is stopped until the operation of the exclusion control means stops, so that the gas body is not excluded during the supply. The supply control means and the exclusion control means are alternately performed, so that the gas body can be infiltrated to the back of the bearing portion and fine floating matters at the back can be excluded.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings. However, the dimensions, materials, shapes, relative positions, and the like of the components described in this embodiment are merely illustrative examples and not intended to limit the scope of the present invention unless otherwise specified. Absent.
[0018]
  FIG. 1 is a basic configuration diagram showing a first embodiment of an oil-free vacuum pump.
  In the figure, the rotary shaft 22 of the pump body 1A is connected to the motor head 2 which is the tip of the motor drive shaft (not shown) at the right end, and is provided to be rotatable about the motor shaft 13 by the rotational force of the motor. ing.
  The central portion of the rotating shaft 22 has an eccentric portion 22Ah whose outer periphery is slightly swelled from the motor shaft 13, and both end portions of the eccentric portion 22Ah are connected to the bearing portions 33A and 34A of the housings 5A and 24A. It is rotatably supported.
[0019]
  The housings 5 </ b> A and 24 </ b> A constituting the fixed scroll each have a circular lid shape, and a peripheral wall functioning as a casing is brought into contact with each other via a seal member 32 to form a sealed space therein.
  The housing 24A is provided with a lap sliding surface 24Ab perpendicular to the axial direction, and the sliding surface 24Ab has a central portion that is out of the eccentric portion 22Ah of the rotating shaft 22A and is not eccentric. An opening that is rotatably fitted is provided, and a spiral wrap 7A is implanted with the vicinity of the opening as a tip. A groove is provided on the upper edge of the wrap 7A. A chip seal 14 having a self-lubricating property such as a fluorine-based resin that is brought into contact with the surface and completes the sealed state is inserted.
[0020]
  A discharge hole 24Ac is formed in the sliding surface 4Ad near the tip of the wrap 7A, and the compressed gas is discharged from the discharge hole 24Ac through the discharge passage 24Ad to the outside through the discharge port portion 9Aa provided on the outer peripheral surface of the housing 24A. It is configured to be.
[0021]
  In addition, three pairs of revolution mechanisms 37 are provided at three positions in the circumferential direction at 120 ° on the peripheral wall portion of the housing 24A.
  The revolution mechanism 37 is connected to a turning scroll described later.
  A suction port portion 8A is provided on the outer peripheral portion of the housing 24A, and the suction port portion 8A is connected to a container (not shown) to be evacuated, and is connected to the inside of the container through the opening portion 8A. Gas is aspirated.
[0022]
  On the other hand, the housing 5A is provided with a lap sliding surface 5Ab perpendicular to the axial direction, and a discharge hole 5Ac is formed in the sliding surface 5Ab, and the outer periphery of the housing 5A passes through the discharge passage 5Ad from the discharge hole 5Ac. The compressed gas is configured to be discharged from the discharge port portion 9Ab provided on the surface to the outside.
  In addition, an opening is provided in the central portion of the sliding surface 5Ab so that the eccentric portion 22Ah of the rotating shaft 22A is off and the non-eccentric portion is rotatably fitted, with the vicinity of the opening as a peripheral end. A spiral wrap 6A is implanted, and a groove is provided on the upper edge of the wrap 6A, and a chip seal 14 is fitted in the groove to contact the mating sliding surface and complete the sealing state. .
[0023]
  The orbiting scroll 3A is removably inserted into the internal space formed by the housings 5A and 24A.
  In the orbiting scroll 3A, laps 26A and 27A that can be fitted to the fixed scroll wraps 6A and 7A provided on the housings 5A and 24A are planted on sliding surfaces 3Ad and 3Ae of a plate formed in a disk shape. .
[0024]
  In the central portion of the orbiting scroll 3A, an opening 3Aa is formed in which the eccentric portion 22Ah of the rotary shaft 22A described above is rotatably fitted, and bearings 39 and 40 are centered on the ring spacer 41 in the opening 3Aa. Dynamic seal members 23 and 25 (FIG. 6) for preventing leakage of grease are disposed on both sides thereof.
  Accordingly, gas can flow into and out of the space between the ring spacer 41 and the rotary shaft 22A from the passage 22Ac, and when there is more inflow than outflow of gas, it acts as the gas reservoir portion 42.
[0025]
  Further, the bearing portion 33A is provided with bearings 44, and dynamic seal members 17 and 21 (FIG. 5) for preventing grease leakage are arranged on both sides thereof.
  Therefore, gas can flow into and out of the space between the bearing 44 and the dynamic seal member 21 from the passage 22Ad, and when there is more inflow than gas outflow, it acts as the gas reservoir portion 43.
[0026]
  The opening 3Aa of the orbiting scroll 3A constitutes a fitting portion with the eccentric portion 22Aa, and the outer peripheral side of the fitting portion is a wrap 26Aa over the entire length of the eccentric portion 22Aa of the rotating shaft 22A. And 27Aa are formed in a spiral manner toward the outer peripheral side.
  Discharge passages 3b and 3c communicating with each other are provided adjacent to the fitting portion. The discharge passages 3b and 3c are provided with opening holes 3g and 3h that open from the final sealed space formed by the fixed wrap and the swirl wrap.
[0027]
  As shown in FIG. 6, a bearing 35 for supporting the rotary shaft 22A is disposed on the bearing portion 34A of the housing 24A. An introduction path 38 is provided from the vicinity of the bearing 35 toward the outer peripheral side of the bearing portion 34A. The introduction path 38 communicates with the introduction path 36a, and the introduction pipe 36 having the introduction path 36a is more than the atmosphere. The gas supply source 49 is connected to a second gas supply source 49 (not shown) containing high-pressure nitrogen gas so that compressed gas can be introduced from the gas supply source 49.
[0028]
  Along with the bearing 35, the dynamic seal members 30, 31 form a ring-shaped gas reservoir portion 24Af having substantially the same cross-sectional area as the introduction passage 38 in the direction of the rotary shaft 22A, and are separated from the gas reservoir portion 24Af. Are arranged.
  As shown in FIG. 8, the reservoir portion 24Af is formed in a ring shape between a dynamic seal member 30 and a dynamic seal member 31 (not shown), and nitrogen gas from a gas supply source is supplied to the reservoir portion 24Af. The
[0029]
  On the other hand, the rotation shaft 22A is provided with a central passage 22Aa on the FIG. 1 along the rotation axis 13, and is configured to be discharged to the left side.
  In FIG. 5, the left end portion 22Ae of the rotating shaft 22A has a D-section (cut into a D shape) perpendicular to the shaft center, and is provided with a screw portion 22Af from the left end. It is fixed by a pressing ring 12 via a pressing plate 11. The holding ring 12 is provided with a central passage 12a communicating with the central passage 22Aa of the rotary shaft 22A.
[0030]
  Further, the end portion 10c of the joint ring 10 is sandwiched between the flange portion of the pressing ring 12 and the pressing plate 11 via the dynamic seal member 16, and the flange portion 10b has a plurality of air circulation holes. The joint cylinder 4 is screwed and fixed to the screw portion 10 a via the static seal member 15. Therefore, although the rotating shaft 22A rotates together with the cooling fan 28, the pressing plate 11, and the joint ring 12, the rotational force is not transmitted from the pressing ring 12 to the joint ring 10.
[0031]
  Further, the joint 4 is screwed to the threaded portion 10 a of the joint ring 10 via a static seal member 15. The joint 4 is provided with a central passage 4 a communicating with the central passage 12 a of the holding ring 12. The joint 4 is connected to a pump 55 described later.
[0032]
  A rotating shaft 22A outside the housing 24A is provided with a fan 29 that cools the vacuum pump, and a cover 19 that protects the fan is attached to the housing 24A with a plurality of air flow holes.
  Further, as described above, one end is supported by the housing 24A on the outer peripheral portion of the orbiting scroll 3A, and the other ends of the three pairs of revolution mechanisms 37 are supported at three positions in the circumferential direction by 120 °. The fixed scroll wrap provided on the housing is arranged so as to revolve with an eccentric rotation center.
[0033]
  In the scroll fluid machine 1A configured as described above, nitrogen gas from a second gas supply source 49 described later is supplied to the central passage 22Aa of the rotary shaft 22A that drives the orbiting scroll 3A.
  In a state where the pump 55 (FIG. 9) disposed downstream of the joint 4 (FIG. 5) is not driven, as shown in FIG. 6, nitrogen is introduced into the central passage 22Aa of the rotary shaft 22A via the gas reservoir 24Af. Gas is supplied and supplied to the gas reservoir 42 from the central passage 22Ac, and the bearings 39 and 40 are filled.
[0034]
  Then, as shown in FIG. 5, the gas enters the gas reservoir 43 from the central passage 22 </ b> Aa through the passage 22 </ b> Ad, fills the periphery of the bearing 44, and enters the gap 58 between the holding ring 12 and the joint 4. .
[0035]
  In this state, when a later-described pump 55 starts operating, the nitrogen gas in the central passage 22Aa of the rotating shaft 22A is discharged to the left in FIG. 1 while the nitrogen gas is being supplied. The gas in the gap 58 and the nitrogen gas around the bearings 44, 39, and 40 are discharged by being sucked by the discharged gas flow.
  Further, the gas in the gas reservoir 24Af is discharged when the amount of gas discharged is larger than the amount of gas flowing in from the passage 38.
[0036]
  Therefore, when the pump 55 is stopped, nitrogen gas flows into the periphery of the bearing and the seal member, and the amount of gas discharged from the gas reservoir 24Af is larger than the amount of gas flowing in from the passage 38. By stopping the inflow of nitrogen gas at the time of driving, the nitrogen gas can be discharged around the bearing and the gas around the seal member when the pump 55 is driven.
[0037]
  FIG. 9 is a schematic block configuration diagram in which the vacuum pump according to the first embodiment is used in a CVD apparatus in a semiconductor manufacturing process.
  In the CVD method, an insulating film such as a SiN film or a conductive film such as a metal film can be deposited on the wafer surface. The gas mainly used in this process is flammable SiH.₄, SiH₂CL₂Explosive H₂, NH₃, CO, toxic SiH₄, NH₃, CO, HCL, SiCL₄Corrosive NH₃, HCL, etc., and the treatment of these gases is a problem.
[0038]
  In FIG. 9, a quartz reaction tube 47 on which a semiconductor wafer 45 is placed is connected to a vacuum pump 1 </ b> A that sucks and exhausts internal gas via an automatic pressure control device 52 and an electromagnetic valve 53. The gas is discharged from the vacuum pump 1A to the chemical processing device 56, and the gas leaking from the fluid compression chamber in the vacuum pump 1A through the bearings is diluted with harmless gas and discharged to the chemical processing device 56 through the pump 55. It is configured to be.
[0039]
  The vacuum pump 1A supplies a large amount of reaction gas by reducing the residual gas in the quartz reaction tube 47 to shorten the reaction time.^-3-10^-2Those having a short-time exhaust capability of about Torr are desirable.
  Further, the chemical treatment device 56 is configured to absorb unreacted gas and reaction products with a filter, or to decompose, oxidize or dilute them and exhaust them to the outside.
[0040]
  The first gas supply source 48 has a valve means for containing the reaction gas inside and controlling the supply of the reaction gas, and the automatic pressure control device 52 has a vacuum gauge inside, and the first gas supply source 48 has a first degree depending on the degree of vacuum. The first gas supply source 48 is operated via the electric control circuit 50 to supply the reaction gas, and the electromagnetic valve 53 is appropriately driven to open and close the valve to the vacuum pump 1A.
[0041]
  Further, the second gas supply source 49 is configured to be able to supply nitrogen gas having a pressure higher than that of the atmosphere, and is connected to the introduction path 38 provided in the housing 24A of the vacuum pump 1A described above via the electromagnetic valve 54, thereby turning the scroll. Nitrogen gas can be supplied to the central passage 22Aa of the rotary shaft 22A that drives 3A.
[0042]
  The first gas supply source 48, the storage heater 46, and the electromagnetic valve 53 are controlled by the first electric control circuit 50, and the vacuum pump 1A, the second gas supply source 49, and the pump 55 can be controlled by the second electric control circuit 51. Configured.
[0043]
  Next, the fluid operation of the scroll mechanism according to the first embodiment configured as described above will be described.
  In FIG. 9, the base 45 and the quartz reaction tube 47 are separated from each other, and the wafer 45 is placed inside the quartz reaction tube 47. The electromagnetic valve 53 is opened by the first electric control circuit 50, and the vacuum pump 1A is driven by the second electric control circuit 51.
[0044]
  In FIG. 1, when the rotary shaft 22A rotates, the orbiting scroll 3A revolves, sucks gas from the quartz reaction tube 47, and gas is discharged from the outer periphery of the fixed scroll wraps 6A and 7A by the wraps 26A and 27A of the orbiting scroll 3A. Are taken into a sealed space formed by the fixed scroll wrap and the orbiting scroll wrap and compressed by the sealed space.
[0045]
  The operation of the sealed space will be described with reference to FIG. 4 using the fixed scroll wrap 7A and the orbiting scroll wrap 27A. The compression space R taken in and compressed by the fixed scroll wrap 7A and the orbiting scroll wrap 27A.₁The compressed gas in (a) is compressed into the compression space R by driving the orbiting scroll.₂After (b), the compression space R₃(A) communicates with the discharge hole 3g and is discharged to the discharge passage 3c.
[0046]
  Further, the compression space S taken in and compressed by the fixed scroll wrap 7A and the orbiting scroll wrap 27A.₁The compressed gas in (b) is compressed into the compression space S by driving the orbiting scroll.₂After (a), the compression space S₃(B) communicates with the discharge hole 3g and is discharged to the discharge passage 3c.
  The discharge passage 3c communicates with the discharge hole 24Ac, and discharge gas is discharged from the discharge hole 24Ac through the discharge passage 24Ad to the external chemical treatment device 56 from the discharge port portion 9Aa provided on the outer peripheral surface of the housing 24A.
[0047]
  On the other hand, since the operation of the pump 55 is stopped, when the electromagnetic valve 54 is opened, the compressed nitrogen gas introduced from the second gas supply source 49 enters the introduction passage 38 from the introduction pipe 36 (FIG. 6), and the gas It is introduced into the central passage 22Aa of the rotating shaft 22A from the pool 24Af. The nitrogen gas passes through the passage 22Ac and fills around the bearings 39 and 40 from the gas reservoir 42. The nitrogen gas also passes through the passage 22Ad and fills around the bearing 44 from the gas reservoir 43, and also enters the gap 58.
[0048]
  In this state, when the electromagnetic valve 54 is closed and the pump 55 is operated, the nitrogen gas in the central passage 22Aa of the rotating shaft 22A is discharged to the left in FIG. Then, the gas in the gap 58 and the nitrogen gas around the bearings 44, 39, and 40 are discharged by being sucked by the discharged gas flow.
  Then, the nitrogen gas is discharged to the external chemical treatment device 56 by the pump 55.
[0049]
  As a result, there is a slight leak in the sealed compression chamber formed by the scroll wrap, and even if the leaked gas reaches the bearing and seal member, it will corrode the bearing and seal member and leak outside the vacuum pump. Can be prevented.
  Further, the pump 55 can be intermittently driven to cool the heat generated by the orbiting scroll 3A within the rotating shaft 22A.
[0050]
  The degree of vacuum in the quartz reaction tube 47 is controlled by the automatic pressure adjusting device 52. When the vacuum pump 1A sucks the gas in the quartz reaction tube 47 to a predetermined degree of vacuum, a evacuation completion signal is sent to the first electric control circuit 50, and the first electric control circuit 50 closes the electromagnetic valve 53, The heater 46 is driven and the first gas supply source 48 is driven to supply the reaction gas to the quartz reaction tube 47.
[0051]
  The automatic pressure adjusting device 52 observes the degree of vacuum in the quartz reaction tube 47 and operates the first gas supply source 48 via the first electric control circuit 50 according to the degree of vacuum to supply the reaction gas. The electromagnetic valve 53 is appropriately driven to open and close the valve to the vacuum pump 1A. When the degree of vacuum is lower than that suitable for film deposition on the wafer, that is, when the pressure of the reaction gas rises above a predetermined value, the electromagnetic valve 53 is opened and the reaction gas is sucked by the vacuum pump 1A to The pressure is controlled to be constant.
[0052]
  When the predetermined time has elapsed, the driving of the first gas supply source 48 and the heater 45 is stopped, the reaction gas in the quartz reaction tube 47 is sucked in by the vacuum pump 1A until the predetermined vacuum degree is reached, and the electromagnetic valve 53 is closed. Then, the driving of the vacuum pump 1A is stopped, the film forming operation is completed, the wafer 45 is taken out from the quartz reaction tube 47, and the inside of the quartz reaction tube 47 is cleaned.
[0053]
  Next, an oil-free vacuum pump according to a second embodiment will be described. The difference from the first embodiment is that there are two compressed fluid discharge passages in the housing in the first embodiment, whereas in the second embodiment there is one, the rotation The introduction form of the compressed gas for dilution provided on the shaft is different from each other. In the second embodiment, the compressed gas for dilution is introduced into the sealed compression chamber of the orbiting scroll.
[0054]
  FIG. 10 is a basic configuration diagram showing a second embodiment of the oil-free vacuum pump.
  In the figure, the rotary shaft 22B of the pump main body 1B is connected to the motor shaft head 2 which is the tip of the motor drive shaft (not shown) at the right end, and is provided to be rotatable about the motor shaft core 13 by the rotational force of the motor. ing.
  The central portion of the rotating shaft 22B has an eccentric portion 22Ba whose outer periphery is slightly swelled from the motor shaft 13, and both end portions of the eccentric portion 22Ba are connected to the bearing portions 33B and 34B of the housings 5B and 24B. It is rotatably supported.
[0055]
  Each of the housings 5B and 24B constituting the fixed scroll has a circular lid shape, and a peripheral wall that functions as a casing is brought into contact with each other via a seal member 32 to form a sealed space therein.
  The housing 24B is provided with a lap sliding surface 24Bb perpendicular to the axial direction, and the sliding surface 24Bb has a central portion that is out of the eccentric portion 22Ba of the rotating shaft 22B and is not eccentric. An opening that fits rotatably is provided, and a spiral wrap 7B is planted with the vicinity of the opening as a tip, and a groove is provided on the upper edge of the wrap 7B. A chip seal 14 having a self-lubricating property such as a fluorine-based resin that is brought into contact with the surface and completes the sealed state is inserted.
[0056]
  On the other hand, the housing 5B is provided with a lap sliding surface 5Bb perpendicular to the axial direction, and a discharge hole 5Bc is formed in the sliding surface 5Bb, and the outer periphery of the housing 5B passes through the discharge passage 5Bd from the discharge hole 5Bc. The compressed gas is discharged to the outside from the discharge port portion 9B provided on the surface.
  In addition, an opening is provided in the central portion of the sliding surface 5Bb so that the eccentric portion 22Bh of the rotating shaft 22B can be rotated and a portion that is not eccentric can be rotatably fitted. A spiral wrap 6B is implanted, and a groove is provided at the upper edge of the wrap 6B. A tip seal 14 is fitted in the groove to make contact with the mating sliding surface and complete the sealing state. .
[0057]
  The orbiting scroll 3B is fitted into the internal space formed by the housings 5B and 24B so as to be able to revolve.
  In the orbiting scroll 3B, laps 26B and 27B that can be fitted to the fixed scroll wraps 6B and 7B provided in the housings 5B and 24B are planted on sliding surfaces 3Bd and 3Be of a plate formed in a disk shape. .
[0058]
  In the central portion of the orbiting scroll 3B, an opening 3Ba is formed in which the eccentric portion 22Bh of the rotary shaft 22B described above is rotatably fitted, and the opening 3Ba has a bearing centering on the ring spacer 60 (FIG. 15). 39 and 40 are arranged, and dynamic seal members 23 and 25 for preventing leakage of grease are arranged on both sides thereof.
  The bearing portion 33B is provided with bearings 44 (FIG. 14), and dynamic seal members 17 and 21 for preventing grease leakage are arranged on both sides thereof.
[0059]
  The opening 3Ba (FIG. 15) of the orbiting scroll 3B constitutes a fitting portion with the eccentric portion 22Bh of the rotating shaft 22B, and the outer peripheral side of this fitting portion is the eccentric portion 22Bh of the rotating shaft 22B. The wraps 26B and 27B are planted in a spiral shape toward the outer peripheral side over the entire length.
[0060]
  The end plate of the orbiting scroll 3B is provided with a passage 3m communicating with the opening 60a provided in the ring spacer 60 toward the outer peripheral side so as to intersect the laps 26B and 27B, and the outer sliding side is bifurcated. The branch branches and communicates as the passages 3i and 3j between the head lands 3Bn forming the bearings of the orbiting scroll 3B and the adjacent laps 26B and 27B.
[0061]
  This configuration will be described in more detail. As shown in FIG. 16, the passage 3j (3i) is located near the lap 27B (26B) adjacent to the main land 3Bn and the opening hole 3g (3h) sandwiches the rotation shaft 22B. It is arranged on the opposite side.
  A gas reservoir 59 is formed between the outer periphery of the rotary shaft 22B and the ring spacer 60 on the distal end side of the passage 22Bb bent from the distal end of the central passage 22Ba to which inert nitrogen gas is supplied. .
[0062]
  Therefore, when nitrogen gas is supplied, the nitrogen gas penetrates in the extending direction of the gas reservoir 59 and the extending direction of the roller pin of the bearing, and the lap 27B (26B) and the main part are passed from the corresponding gas reservoir 59 through the passage 3m. It is supplied between the land 3Bn.
[0063]
  Further, as shown in FIG. 15, a discharge passage 3k that is adjacent to the fitting portion and communicates with each other is provided. The discharge passage 3k is provided with opening holes 3g and 3h which open from the final sealed space formed by the fixed wrap and the swirl wrap.
  A bearing 35 that supports the rotary shaft 22B is disposed on the bearing portion 34B of the housing 24B, and a dynamic seal member 30 that prevents leakage of grease is disposed along with the bearing 35.
[0064]
  On the other hand, the rotary shaft 22B is provided with the central passage 22Ba described above on FIG. 10 along the rotary axis 13 so that compressed nitrogen gas can be introduced from the joint 4 on the left side. The sectional area of the central passage 22Ba is formed larger than the sectional area of the passage 3m.
  In FIG. 14, the left end portion 22Be of the rotating shaft 22B has a D-section (cut into a D shape) perpendicular to the axis, and is provided with a screw portion 22Bf from the left end. A cooling fan 28 is provided in the D cut portion 22Bg. It is fixed by a pressing ring 12 via a pressing plate 11. The holding ring 12 is provided with a central passage 12a communicating with the central passage 22Ba of the rotary shaft 22B. The sectional area of the central passage 12a is formed to be equal to or larger than the sectional area of the central passage 22Ba of the rotating shaft 22b.
[0065]
  Further, the end portion 10c of the joint ring 10 is sandwiched between the flange portion of the pressing ring 12 and the pressing plate 11 via the dynamic seal member 16, and the flange portion 10b has a plurality of air circulation holes. The joint cylinder 4 is screwed and fixed to the screw portion 10 a via the static seal member 15. Therefore, although the rotating shaft 22B rotates together with the cooling fan 28, the pressing plate 11, and the joint ring 12, the rotational force is not transmitted from the pressing ring 12 to the joint ring 10.
[0066]
  Further, the joint 4 is screwed to the threaded portion 10 a of the joint ring 10 via a static seal member 15. The joint 4 is provided with a central passage 4 a communicating with the central passage 12 a of the holding ring 12. The cross-sectional area of the central passage 4a is formed to be equal to or larger than the cross-sectional area of the central passage 12a. The joint 4 is connected to a second gas supply source 49 via an electromagnetic valve 54 described later.
[0067]
  The rotating shaft 22B has a plurality of passages 22Bd branched from the central passage 22Ba toward one end of the bearing 44, and the sectional area of the central passage 22Ba is larger than the sectional area of the passage 3m. When nitrogen gas is supplied from the supply source 49 at a predetermined pressure, the nitrogen gas is easily supplied to the bearing 44 side through the passage 22Bd. The dynamic seal members 17 and 21 are configured to be filled with nitrogen gas compressed around the bearing 44.
[0068]
  As shown in FIG. 10, a fan 29 for cooling the vacuum pump is provided on the rotary shaft 22B outside the housing 24B, and a cover 19 for protecting the fan has a plurality of air circulation holes. It is attached to 24B.
  In addition, on the outer peripheral portion of the orbiting scroll 3B, three pairs of revolution mechanisms are supported at three locations in the circumferential direction at 120 °, not shown, and are eccentric from the fixed scroll wrap provided on the housing via the revolution mechanism. It is arranged to revolve with a center of rotation.
[0069]
  In the scroll fluid machine 1B configured as described above, nitrogen gas from a second gas supply source 49 described later is supplied to the central passage 22Ba of the rotary shaft 22B that drives the orbiting scroll 3B.
  Then, nitrogen gas is supplied from the passage 22Bd to the bearing 44 side as shown in FIG. 14, and nitrogen gas is supplied from the passage 22Bb to the gas reservoir 59 as shown in FIGS. To charge.
[0070]
  Then, as shown in FIGS. 15 and 16, nitrogen gas is supplied from the passage 3m through the passages 3j and 3i between the wrap 27B (26B) and the main land 3Bn.
  In this state, when the vacuum pump 1B starts operating, a negative pressure is initially applied to the sealed space formed by the fixed scroll wrap and the orbiting scroll wrap, and nitrogen gas is supplied while nitrogen gas is being supplied. Residual gas is discharged from the discharge port 5Bc. The sealed space takes in the gas in the reaction tube, and as the gas is compressed, the intake of nitrogen gas decreases. As the degree of vacuum in the reaction tube increases, the amount of nitrogen gas taken in increases. To do. Then, when the reaction tube reaches a predetermined degree of vacuum, the supply of nitrogen gas from the second gas supply source 49 is stopped. When the supply of nitrogen gas stops, around each bearingI was just waitingNitrogen gas is sucked to the side of the scroll wrap that has a negative pressure, and is discharged from the discharge port 5Bc.
[0071]
  FIG. 17 is a schematic block configuration diagram in which the vacuum pump according to the second embodiment is used in a CVD apparatus in a semiconductor manufacturing process.
  In FIG. 17, a quartz reaction tube 47 on which a semiconductor wafer 45 is placed is connected to a vacuum pump 1 </ b> B that sucks and exhausts internal gas via an automatic pressure control device 52 and an electromagnetic valve 53. The gas is discharged from the vacuum pump 1B to the discharged fluid processing device 56, and the reaction gas compressed from the fluid compression chamber in the vacuum pump 1B is discharged to the discharged fluid processing device 56.
[0072]
  The vacuum pump 1B supplies a large amount of reaction gas by reducing the residual gas in the quartz reaction tube 47 to shorten the reaction time.^-3-10^-2Those having a short-time exhaust capability of about Torr are desirable.
  Further, the discharged fluid processing device 56 is configured to absorb unreacted gas and reaction products with a filter, or to decompose, oxidize or dilute them and exhaust them to the outside.
[0073]
  The first gas supply 48 has a valve means for containing the reaction gas inside and controlling the supply of the reaction gas, and the automatic pressure control device 52 is provided with a vacuum gauge inside, and the first electric supply 48 depends on the degree of vacuum. The first gas supply source 48 is operated via the control circuit 50 to supply the reaction gas, and the electromagnetic valve 53 is appropriately driven to open and close the valve to the vacuum pump 1B.
[0074]
  The second gas supply source 49 is configured to be able to supply nitrogen gas having a pressure higher than that of the atmosphere, and rotates to drive the orbiting scroll 3B via the electromagnetic valve 54 and the joint 4 of the vacuum pump 1B described above. Nitrogen gas can be supplied to the central passage 22Ba of the shaft 22B.
[0075]
  The first gas supply source 48, the storage heater 46 and the electromagnetic valve 53 are controlled by the first electric control circuit 50, and the vacuum pump 1B and the second gas supply source 49 can be controlled by the second electric control circuit 51. Is done.
[0076]
  Next, the fluid operation of the scroll mechanism according to the second embodiment configured as described above will be described.
  In FIG. 17, the base 45 and the quartz reaction tube 47 are separated from each other, and the wafer 45 is placed inside the quartz reaction tube 47. The electromagnetic valve 53 is opened by the first electric control circuit 50, and the vacuum pump 1B is driven by the second electric control circuit 51.
[0077]
  In FIG. 10, when the rotary shaft 22B rotates, the orbiting scroll 3B revolves and sucks gas from the quartz reaction tube 47, and gas is supplied from the outer periphery of the fixed scroll wraps 6B and 7B by the wraps 26B and 27B of the orbiting scroll 3B. Are taken into a sealed space formed by the fixed scroll wrap and the orbiting scroll wrap and compressed by the sealed space.
[0078]
  The operation of this sealed space will be described using the fixed scroll wrap 7B and the orbiting scroll wrap 27B with reference to FIG. 13. The compression space R taken in and compressed by the fixed scroll wrap 7B and the orbiting scroll wrap 27B.₁The compressed gas in ′ (b) is compressed into the compression space R by driving the orbiting scroll.₂′ (B), compression space R₃'(B) communicates with the discharge hole 3g and is discharged to the discharge passage 3k.
[0079]
  Further, the compression space S taken in and compressed by the fixed scroll wrap 7B and the orbiting scroll wrap 27B.₁The compressed gas in ′ (a) is compressed into the compression space S by driving the orbiting scroll.₂′ (B), the compression space S₃'(A) communicates with the discharge hole 3g and is discharged to the discharge passage 3k.
[0080]
  When the nitrogen gas passage 3j (3i) is blocked by the fixed scroll wrap 7B (6B) as shown in (a), the supply of nitrogen gas is interrupted, but as shown in (b), the fixed scroll wrap 7B (6B) is interrupted. ) Is out of compression space S₂′ Is supplied to the compression space S₃It is discharged from the discharge hole 3g at ′ (a).
[0081]
  On the other hand, when the electromagnetic valve 54 is opened in synchronization with the driving of the vacuum pump 1B, the compressed nitrogen gas flowing in from the second gas supply source 49 is supplied to the central passage 22Ba of the rotary shaft 22B that drives the orbiting scroll 3B. The
  Then, nitrogen gas is supplied from the passage 22Bd to the bearing 44 side as shown in FIG. 14, and further enters the gap 58 from the passage 4a on the way, and nitrogen is supplied from the passage 22Bb to the gas reservoir 59 as shown in FIGS. Gas is supplied and fills around the bearings 39, 40.
[0082]
  Then, as shown in FIGS. 15 and 16, nitrogen gas is supplied from the passage 3m through the passages 3j and 3i between the wrap 27B (26B) and the main land 3Bn.
  When the supply of nitrogen gas is started after the vacuum pump 1B starts operating, the sealed space formed by the fixed scroll wrap and the orbiting scroll wrap is initially at a negative pressure and remains in a state in which no nitrogen gas is supplied. Then, the remaining gas and the air taken in are discharged from the discharge port 5Bc, but the sealed space starts to take in the nitrogen gas by the supply of the nitrogen gas.
[0083]
  At first, the intake of nitrogen gas is small, but the gas approach from the reaction tube of the vacuum pump 1B is promoted, and the intake amount of nitrogen gas increases as the degree of vacuum of the reaction tube advances. When the reaction tube reaches a predetermined degree of vacuum, the electromagnetic valve 54 is closed and the supply of nitrogen gas from the second gas supply source 49 is stopped.
  When the supply of the nitrogen gas is stopped, the nitrogen gas that has settled around each bearing portion is sucked to the scroll wrap side where the negative pressure is reached and discharged from the discharge port 5Bc.
  Then, the operation of the vacuum pump 1B is stopped. The discharged nitrogen gas and / or reaction gas is discharged to an external discharge fluid processing device 56.
[0084]
  As a result, there is a slight leak in the sealed compression chamber formed by the scroll wrap, and even if the leaked gas reaches the bearing and seal member, it will corrode the bearing and seal member and leak outside the vacuum pump. Can be prevented.
  Moreover, since nitrogen gas distribute | circulates the inside of the rotating shaft 22B, the heat which the turning scroll 3B generate | occur | produces can be cooled.
[0085]
  The degree of vacuum in the quartz reaction tube 47 is controlled by the automatic pressure adjusting device 52. When the vacuum pump 1B sucks the gas in the quartz reaction tube 47 to a predetermined degree of vacuum, a vacuuming completion signal is sent to the first electric control circuit 50, and the first electric control circuit 50 closes the electromagnetic valve 53, The heater 46 is driven and the first gas supply source 48 is driven to supply the reaction gas to the quartz reaction tube 47.
[0086]
  The automatic pressure adjusting device 52 observes the degree of vacuum in the quartz reaction tube 47 and operates the first gas supply source 48 via the first electric control circuit 50 according to the degree of vacuum to supply the reaction gas. The electromagnetic valve 53 is appropriately driven to open and close the valve to the vacuum pump 1B. When the degree of vacuum is less than that suitable for film deposition on the wafer, that is, when the pressure of the reaction gas rises above a predetermined value, the electromagnetic valve 53 is opened and the reaction gas is sucked in by the vacuum pump 1B. The pressure is controlled to be constant.
[0087]
  When the predetermined time elapses, the driving of the first gas supply source 48 and the heater 46 is stopped, the electromagnetic valve 54 is opened, and simultaneously with the supply of nitrogen gas, the reaction gas in the quartz reaction tube 47 is supplied to the predetermined vacuum degree by the vacuum pump 1B. The electromagnetic valve 54 is closed, the supply of nitrogen gas is stopped, the electromagnetic valve 53 is closed after a predetermined time, the driving of the vacuum pump 1B is stopped, and the film forming operation is completed. The wafer 45 is taken out from the quartz reaction tube 47 and the inside of the quartz reaction tube 47 is cleaned.
[0088]
【The invention's effect】
  As described above, by using the scroll fluid machine of the present invention,Since the gas body introduced by the gas body introduction means is discharged in a mixed state with the air discharged from the decompression means and / or the compressed fluid of the reaction gas, a special gas body discharge means dedicated to the gas body is provided. There is no need, and the configuration is simplified.
  Then, a gas body different from the reaction gas is introduced into a sliding portion between the driving member and the counterpart member that slides face to face in the decompression means, and the introduced gas body and the air discharged by the decompression means And / or the compressed fluid of the reaction gas is supplied to the exhaust fluid processing means, so that impurities on the upstream side of the decompression means are sent to the exhaust fluid treatment device in the compression / discharge process of the decompression means and rendered harmless. Treated and leaked reaction gas leaked to the sliding part and fine suspended matter generated from the sliding part are also sent to the exhaust fluid treatment device to be detoxified, so that it is flammable, explosive, toxic and corrosive Or the like can be prevented from leaking into the environment of the semiconductor processing line.
[0089]
  In particular,Book number1In the present invention, a gas body different from the reaction gas is introduced into the sliding portion of the driving member and the counterpart member that slide against each other in the decompression means, and is generated from the sliding portion by the introduced gas body. Since the fine suspended matter is discharged, the durability of the sliding portion is improved and the scroll mechanism can be cooled.
[0090]
  In addition, this book2Since the invention is a double wrap type scroll machine, the amount of fluid taken in is large, and when used as a vacuum pump, it can reach a predetermined vacuum level quickly.
  Further, since the gas body passage for introducing the gas body from one of the rotary drive shafts and discharging the gas body from the other is formed along the extending direction of the rotary drive shaft, the scroll mechanism is cooled. be able to.
  Further, a branch passage is formed from the gas body passage so that the gas body can be supplied to the bearing and the seal member, so that the fine suspended matter generated from the sliding portion is discharged by the introduced gas body. Thus, durability of the sliding portion and the seal member can be improved.
  Then, after the gas body is introduced by the supply control means, the supply control means is stopped until the operation of the exclusion control means stops, so that the gas body is not excluded during the supply. The supply control means and the exclusion control means are alternately performed, so that the gas body can be infiltrated to the back of the bearing portion and fine floating matters at the back can be excluded.
[Brief description of the drawings]
FIG. 1 is a basic configuration diagram showing a first embodiment of an oil-free scroll fluid machine according to the present invention.
FIG. 2 is a left side view of the orbiting scroll in FIG.
3 is a right side view of the orbiting scroll in FIG. 1. FIG.
FIG. 4 is an explanatory diagram for explaining the compression operation of the orbiting scroll wrap and the fixed scroll wrap.
FIG. 5 is an enlarged view of a main part of FIG. 1;
6 is an enlarged view of a main part of FIG.
7 is a cross-sectional view taken along the line AA in FIG.
8 is a cross-sectional view taken along the line BB in FIG.
FIG. 9 is a block configuration diagram showing an embodiment of a semiconductor manufacturing apparatus using the scroll fluid machine of the present invention.
FIG. 10 is a basic configuration diagram showing a second embodiment of the oil-free fluid machine according to the present invention.
11 is a right side view of the orbiting scroll in FIG.
12 is a left side view of the orbiting scroll in FIG. 1. FIG.
FIG. 13 is an explanatory diagram for explaining the compression operation of the orbiting scroll wrap and the fixed scroll wrap.
14 is an enlarged view of a main part of FIG.
15 is an enlarged view of a main part of FIG.
16 is a cross-sectional view taken along the line CC of FIG.
FIG. 17 is a block diagram showing a second embodiment of a semiconductor manufacturing apparatus using the scroll fluid machine of the present invention.
[Explanation of symbols]
  8A vacuum pump (pressure reduction means)
  45 Semiconductor wafer
  47 Quartz reaction tube
  56 Discharged fluid treatment device

Claims (2)

In a scroll fluid machine having a fixed scroll and an orbiting scroll, the orbiting scroll wrap is orbitally revolved with respect to the fixed scroll wrap by a rotary drive shaft having an eccentric portion that comes into contact with the central portion of the orbiting scroll end plate.
The rotary drive shaft is formed such that a gas body is introduced from the outside so that the gas body can be discharged,
The gas body can be supplied to a bearing provided between the orbiting scroll and the rotary drive shaft facing the rotary drive shaft,
The gas body cools the scroll mechanism and discharges impurities around the bearing ,
Furthermore, a gas body passage for introducing the gas body from one of the rotation drive shafts and discharging the gas body from the other is formed along the extending direction of the rotation drive shaft, and from the gas body passage to the bearing. Form a branch passage,
A supply control means for controlling supply of a gas body from the outside to the gas body passage; and an exclusion control means for removing the gas body from the gas body passage;
After the introduction of the gas body by the supply control means, the supply control means is stopped until the operation of the exclusion control means is stopped . A rotary drive shaft having a double wrap type orbiting scroll and fixed scrolls arranged on both sides facing the mirror surface of the orbiting scroll end plate and having an eccentric portion abutting against a central portion of the orbiting scroll end plate In the scroll fluid machine of the type in which the orbiting scroll wrap orbits and revolves with respect to the fixed scroll wrap,
A bearing and a seal member provided between the orbiting scroll and the fixed scroll and the rotary drive shaft facing the rotary drive shaft;
A gas body passage for introducing a gas body from one of the rotation drive shafts and discharging the gas body from the other is formed along the extending direction of the rotation drive shaft, and a branch passage is formed from the gas body passage. The gas body can be supplied to the bearing and the seal member,
A supply control means for controlling supply of a gas body from the outside to the gas body passage; and an exclusion control means for removing the gas body from the gas body passage;
After the introduction of the gas body by the supply control means, the supply control means is stopped until the operation of the exclusion control means is stopped.

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