JP2008044064A - Polishing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing device capable of determining the change time of a rotary joint. <P>SOLUTION: The polishing device is equipped with a polishing member 60 capable of polishing a wafer, a rotatable polishing head 30 for holding the polishing member 60, a rotary holding member for rotatably holding the polishing head 30, and first and second rotary joints 90, 100 which connect pipe paths 71, 72, 73 provided on the rotary holding member with the pipe paths 65, 66, 67 provided inside of the polishing head 30. The polishing device is constituted so that the purified water is supplied from the outside to the first and second rotary joints 90, 100, and is provided with a specific gravity meter 88 for measuring the specific gravity by taking out the purified water supplied to the first and second rotary joints 90, 100. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a polishing apparatus for flattening the surface of an object to be polished such as a semiconductor wafer.

  Conventionally, as a polishing apparatus for flattening the surface of an object to be polished such as a semiconductor wafer, a wafer holding apparatus for holding the wafer in a state where the polished surface is exposed, and a polished surface of the wafer held by the wafer holding apparatus And a polishing head for holding a polishing member to which a polishing pad opposite to the substrate is attached. While both of them are rotated, the polishing pad is pressed against the surface to be polished of the wafer, and the polishing body is in the in-contact direction of both There is known a configuration in which a wafer is polished by swinging it (see, for example, Patent Document 1). Further, in addition to such mechanical polishing, chemical mechanical polishing (Chemical Mechanical Polishing) that supplies the polishing agent (slurry) to the contact surface between the polishing pad and the wafer and promotes the polishing by the chemical action of the polishing agent. CMP apparatus for performing CMP) is also known.

As means for supplying the slurry to the contact surface between the polishing pad and the wafer, the slurry supply device, a fixed side line connected to the slurry supply unit, and a rotation side line provided inside the polishing head, the slurry The slurry pumped from the supply device passes through the fixed side pipe and the rotary side pipe and is supplied to the contact surface between the polishing pad and the wafer from the slurry supply hole provided in the polishing member. The fixed side pipe and the rotary side pipe are connected by using a so-called rotary joint, and this rotary joint includes cooling and lubrication of a sealing surface of a mechanical seal provided in the rotary joint, and the rotary joint. Pure water (also referred to as quench water) that seals the slurry that passes through is supplied.
Japanese Patent Laid-Open No. 11-156711

  When the rotary joint as described above breaks, for example, mechanical seal fragments enter the side of the passage through which the slurry passes, and mechanical seal fragments enter the slurry, so-called micro-scratch may occur in the polished wafer. There was sex. However, in the past, the rotary joint was only periodically replaced (for example, every six months), and the replacement time of the rotary joint was not specifically determined.

  This invention is made | formed in view of such a problem, and it aims at providing the grinding | polishing apparatus which can determine the replacement time of a rotary joint.

  In order to achieve such an object, in the present invention, a polishing member capable of polishing an object to be polished, a rotating member that holds and rotates the polishing member, a rotation holding member that rotatably holds the rotating member, and a rotation A rotary joint that connects the conduit provided in the holding member and the conduit provided in the rotating member, and configured to polish the polishing object by moving the polishing member relative to the polishing object while abutting the polishing member. The polishing apparatus is configured such that at least a liquid used for cooling the rotary joint is supplied from the outside to the rotary joint, and at least a part of the liquid supplied to the rotary joint is taken out to improve the physical properties of the liquid. It has a physical property measuring device for measuring.

  Moreover, in the above-mentioned invention, it is preferable that the physical property measuring device is a hydrometer that measures the specific gravity of the liquid.

  Furthermore, the physical property measuring device may be a fine particle counter that measures the number of pieces of the seal member constituting the rotary joint contained in the liquid.

  According to the present invention, it is possible to determine the replacement time of the rotary joint.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a CMP apparatus (chemical mechanical polishing apparatus) which is a representative example of the polishing apparatus according to the present invention. The CMP apparatus 1 is provided at a position above the wafer holding table 15, and is held on the wafer holding table 15. And a polishing head 30 that holds a polishing member 60 to which a polishing pad 64 facing the surface to be polished 10s of the wafer 10 is attached. In the CMP apparatus 1, the size (diameter) of the polishing pad 64 is smaller than the size (diameter) of the wafer 10 to be polished (that is, the polishing pad 64 is smaller in diameter than the wafer 10). By moving the both relative to each other in the contact state, the entire surface (upper surface) 10 s of the wafer 10 can be polished.

  A support frame 20 that supports the wafer holding table 15 and the polishing head 30 extends in a Y direction (this is a direction perpendicular to the paper surface in the front-rear direction) on a horizontal base 21 and the base 21. A first stage 22 provided on a rail (not shown) provided so as to be movable in the Y direction, a vertical frame 23 provided so as to extend vertically (Z direction) from the first stage 22, and A second stage 24 provided movably in the Z direction (vertical direction) on the vertical frame 23, a horizontal frame 25 provided to extend horizontally (X direction) from the second stage 24, and the horizontal The third stage 26 is configured to be movable on the frame 25 in the X direction (left and right direction).

  A first electric motor M1 is provided in the first stage 22, and the first stage 22 can be moved in the Y direction along the rail by being driven to rotate. A second electric motor M2 is provided in the second stage 24, and the second stage 24 can be moved in the Z direction along the vertical frame 23 by being driven to rotate. Further, a third electric motor M3 is provided in the third stage 26, and the third stage 26 can be moved in the X direction along the horizontal frame 25 by rotationally driving the third electric motor M3. Therefore, the third stage 26 can be moved to an arbitrary position above the wafer holding table 15 by combining the rotation operations of the electric motors M1 to M3.

  The wafer holding table 15 is horizontally attached to an upper end portion of a rotary shaft 28 provided vertically extending from a table support portion 27 provided on the base 21. The rotary shaft 28 is rotated by rotationally driving a fourth electric motor M4 provided in the table support portion 27, thereby rotating the wafer holding table 15 in the XY plane (horizontal plane). be able to.

  The polishing head 30 is attached to a lower end portion of a spindle 29 that extends vertically downward from the third stage 26. The spindle 29 is rotated by rotationally driving a fifth electric motor M5 provided in the third stage 26. As a result, the entire polishing head 30 is rotated to bring the polishing pad 64 into the XY plane ( In a horizontal plane). That is, the polishing head 30 and the spindle 29 are rotatably held on the third stage 26.

  As shown in FIG. 2, the polishing head 30 includes a bottomed cylindrical head housing 32 having an opening on the lower surface side connected to a lower end portion of a spindle 29 via a connection member 31, and a ring housing (not shown). A disk-shaped drive plate 33 having an outer peripheral portion sandwiched between the holding plate 40, a holding plate 40 connected to the lower side of the drive plate 33, and a polishing member 60 adsorbed and held on the lower surface side of the holding plate 40. Configured.

  The drive plate 33 is formed in a disk shape having a circular hole in the center using a metal plate such as an austenitic stainless steel plate, and the outer peripheral portion thereof is sandwiched and fixed between the ring member 35 and the inner portion of the head housing 32. It is like that. The drive plate 33 is formed with a large number of concentric openings (not shown) so that air in the head housing 32 can pass through the openings. The inner peripheral portion of the drive plate 33 is sandwiched between a center member 34 formed in a disk shape and a holding plate 40 using a fastening member such as a bolt. As described above, the holding plate 40 is fixed to the head housing 32 via the drive plate 33 and the central member 34, and the rotational driving force of the spindle 29 is transmitted to the holding plate 40 via the drive plate 33 and the central member 34. The

  A first joint J1 is attached to a through hole formed in the central portion of the center member 34, and the slurry rotation side pipe 65 disposed in the spindle 29 and the polishing head 30 is connected to the first joint J1. Are connected at the lower end. Further, a second joint J2 is attached to a through hole formed on the outer peripheral side of the center member 34, and a suction rotation side tube disposed inside the spindle 29 and the polishing head 30 is attached to the second joint J2. The lower end of the path 66 is connected.

  The holding plate 40 is formed in a disk shape whose outer diameter is slightly smaller than the inner diameter of the opening of the head housing 32, and the holding plate 40 closes the opening of the head housing 32 so that the inside of the head housing 32 is sealed. An internal space H is formed by being surrounded by the plate 40 and the inner portion of the head housing 32. The internal space H communicates with the electropneumatic rotary side pipe 67 formed through the center of the spindle 29, and the air passing through the electropneumatic rotary side pipe 67 is inside the head housing 32. To be supplied. Note that the electropneumatic rotating side pipe 67 is connected to the electropneumatic regulator 84 so that the air pressure in the head housing 32 can be adjusted to a desired pressure by the air supplied from the electropneumatic regulator 84. .

  A suction hole 45 is formed inside the holding plate 40, and an upper end portion of the suction hole 45 is connected to the second joint J <b> 2 and a plurality of lower end portions are opened on the lower surface side of the holding plate 40. The suction holes 45 extend radially inside the holding plate 40.

  The polishing member 60 includes a carrier member 61 that is detachably attached to the holding plate 40 and a pad plate 62 that is attached to the lower side of the carrier member 61. The carrier member 61 is formed in a disk shape using a metal material, and a pad plate 62 is detachably attached to the lower side of the carrier member 61.

  The pad plate 62 includes a resin plate member 63 and a polishing pad 64 attached to the lower surface side of the plate member 63. The plate member 63 is formed in a disk shape using a resin material such as PET (polyethylene-terephthalate), and the polishing pad 64 capable of polishing the surface of the wafer 10 (surface 10s to be polished) flatly uses a double-sided adhesive tape or the like. The plate member 63 is attached to the lower surface side. On the lower surface of the polishing pad 64, a polishing surface 64 s is formed that is in contact with the surface of the wafer 10 (surface to be polished 10 s) and performs polishing. The slurry supply hole 46 is formed so as to be connected to the center of the holding plate 40 and the polishing member 60 so as to extend vertically. The upper end of the slurry supply hole 46 is connected to the first joint J1, and the lower end is downward. It is designed to open.

  By the way, the third stage 26 on which the spindle 29 and the polishing head 30 are rotatably supported is provided with a slurry fixed side pipe 71, and the tip of the slurry fixed side pipe 71 is the first rotary. It is connected to the upper end portion of the slurry rotation side pipe 65 via a joint 90. The base end portion of the slurry fixed side pipe 71 is connected to the slurry supply device 80, and the slurry supplied from the slurry supply device 80 passes through the slurry fixed side pipe 71 and the slurry rotation side pipe 65. It is configured to flow out from the slurry supply hole 46 to the outside.

  The third stage 26 is provided with a suction fixed side pipe 72 and an electropneumatic fixed side pipe 73, and the tips of the suction fixed side pipe 72 and the electropneumatic fixed side pipe 73 are arranged. The respective parts are connected to the upper ends of the suction rotary side pipe 66 and the electropneumatic rotary side pipe 67 via the second rotary joint 100. The proximal end portion of the suction fixed side pipe line 72 is connected to the vacuum pump 82 via the switching valve 81, and the switching valve 81 is switched so that the vacuum pump 82 and the suction fixed side pipe line 72 are connected. By applying a negative pressure to the suction hole 45 connected to the suction fixed side pipe 72 and the suction rotation side pipe 66 using the vacuum pump 82, the polishing member 60 is sucked and held by the holding plate 40. It is configured.

  Further, the proximal end portion of the adsorption fixed side pipe line 72 is connected to the first pure water supply unit 83 via the switching valve 81, and the first pure water supply unit 83 and the adsorption fixed side pipe line 72 are connected to each other. Thus, the switching valve 81 is switched and the pure water is supplied from the first pure water supply unit 83 to the suction hole 45 through the suction fixed side pipe 72 and the suction rotary side pipe 66, thereby polishing. The member 60 is configured to be removable from the holding plate 40.

  Further, the base end portion of the electropneumatic fixed side pipe 73 is connected to a compressor 85 which is an air pressure source via an electropneumatic regulator 84. Then, air having a desired pressure is supplied from the compressor 85 and the electropneumatic regulator 84 to the internal space H of the head housing 32 through the electropneumatic fixed side pipe 73 and the electropneumatic rotary side pipe 67. The polishing member 60 (polishing pad 64) adsorbed and held by the holding plate 40 using the pressure of the air supplied to the internal space H is configured to be able to press the wafer 10.

  The second rotary joint 100 is connected to the upper end of the spindle 29 and is inserted into the cylindrical second body 101 fixed to the third stage 26 side and the second body 101 so as to be rotatable. And the second rotor 110. The hole formed in the side portion of the second body 101 is connected to the seventh joint J7 to which the distal end portion of the suction fixed side conduit 72 is connected and the distal end portion of the electropneumatic fixed side conduit 73. An eighth joint J8, a ninth joint J9 to which the lower end of the pure water relay pipe 75 is connected, and a tenth joint J10 to which the pure water drain pipe 76 is connected.

  The second rotor 110 has an upper end connected to the first rotor 92 of the first rotary joint 90 and a lower end connected to the upper end of the spindle 29. An upper rotation side fluid passage 111 and a lower rotation side fluid passage 112 are formed in the second rotor 110.

  In the seal space S sealed between the second body 101 and the second rotor 110, an upper mechanical seal 120 and a lower mechanical seal 125 are disposed along the second rotor 110. The upper mechanical seal 120 is provided with an upper fixing seal ring 121 fixed to the second body 101 and an upper rotation sealing ring that is provided so as to sandwich the upper fixing seal ring 121 and that can rotate together with the second rotor 110. 123.

  An upper fixed side fluid passage 122 is formed inside the upper fixing seal ring 121, and one end is connected to the eighth joint J 8, and the other end is surrounded by the upper fixing seal ring 121 and the upper rotating seal ring 123. In addition, it is connected to one end of the upper rotation side fluid passage 111 through a sealed chamber (not shown). The other end of the upper rotation side fluid passage 111 opens at the lower end of the second rotor 110 and is connected to the upper end of the electropneumatic rotation side pipe 67 in the spindle 29.

  The lower mechanical seal 125 is provided with a lower fixing seal ring 126 fixed to the second body 101, and a lower rotation sealing ring that is provided so as to sandwich the lower fixing seal ring 126 between the upper and lower portions and is rotatable together with the second rotor 110. 128. A lower fixed side fluid passage 127 is formed inside the lower fixing seal ring 126, one end is connected to the seventh joint J 7, and the other end is surrounded by the lower fixing seal ring 126 and the lower rotation seal ring 128. It is connected to one end of the lower rotation side fluid passage 112 via a sealed chamber (not shown). The other end of the lower rotation side fluid passage 112 is connected to the upper end portion of the adsorption rotation side conduit 66 through an eleventh joint J11 provided at the lower end portion of the second rotor 110.

  The ninth joint J9 is connected to the lower outer periphery of the seal space S so that pure water is supplied into the seal space S through the pure water relay pipe 75. This pure water is referred to as quench water. When the seal space S is filled with this pure water, cooling and lubrication of the seal surface in each mechanical seal and fluid (air) passing through the second rotary joint 100 are performed. And pure water). Further, the tenth joint J10 is connected to the upper outer peripheral portion of the seal space S, and the pure water in the seal space S is discharged to the drain port 87 through the tenth joint J10 and the pure water drain pipe 76. Yes.

  The first rotary joint 90 has the same structure as the second rotary joint 100, and is inserted into the first body 91 in a rotatable manner with a cylindrical first body 91 fixed to the third stage 26 side. The first rotor 92 is configured. The first rotary joint 90 is located above the second rotary joint 100. The hole formed in the side part of the first body 91 is connected to the third joint J3 to which the tip end of the fixed side pipe 71 for slurry is connected and the tip of the pure water supply pipe 74 to which the tip is connected. A four joint J4 and a fifth joint J5 to which the upper end of the pure water relay pipe 75 is connected are attached.

  The base end of the pure water supply pipe 74 is connected to the second pure water supply part 86, and pure water is supplied from the second pure water supply part 86 to the first rotary joint 90 via the pure water supply pipe 74. It has come to be. The role of pure water supplied to the first rotary joint 90 is the same as that of the second rotary joint 100. The first and second pure water supply units 83 and 86 have manifolds connected to a pure water supply device (not shown) outside the polishing apparatus 1 and are supplied from the pure water supply device. A part of water is taken into each part of the polishing apparatus 1.

  The lower end of the first rotor 92 is connected to the second rotor 110 of the second rotary joint 100. Further, a sixth joint J6 is attached to the lower end portion of the first rotor 92, and the internal passage of the first rotor 92 is connected to the upper end portion of the slurry rotation side pipe 65 via the sixth joint J6. Yes. A sealed space (not shown) is formed between the first body 91 and the first rotor 92, and a set of mechanical seals (not shown) is provided along the first rotor 92 in the sealed space. However, since the configuration is the same as that of the second rotary joint 100, detailed illustration and description are omitted.

  By the way, a part of the pure water passing through the pure water relay pipe line 75 can be sent to the hydrometer 88 from the branch part 75 a provided in the pure water relay pipe 75, and the first rotary joint 90 is used by the hydrometer 88. The specific gravity of pure water supplied to can be measured. Further, a part of the pure water passing through the pure water drain pipe 76 can be sent to the hydrometer 88 from the branching portion 76 a provided in the pure water drain pipe 76, and the hydrometer 88 is supplied to the second rotary joint 100. The specific gravity of the supplied pure water can be measured.

  In order to polish the wafer 10 using the CMP apparatus 1 having such a configuration, first, the wafer 10 to be polished is sucked and attached to the upper surface of the wafer holding table 15 (at this time, the center of the wafer 10 is the wafer holding table 15). The wafer holding table 15 is rotated by driving the electric motor M4. Next, the electric motors M1 to M3 are driven to position the third stage 26 above the wafer 10, and the spindle 29 is driven by the electric motor M5 to rotate the polishing head 30. Subsequently, the electric motor M2 is driven to lower the third stage 26 so that the lower surface (polishing surface 64s) of the polishing pad 64 is pressed against the upper surface (surface 10s to be polished) of the wafer 10.

  Next, a desired pressure is applied to the internal space H of the head housing 32 from the compressor 85 and the electropneumatic regulator 84 via the electropneumatic fixed side pipe 73, the second rotary joint 100, and the electropneumatic rotary side pipe 67. And the contact pressure between the wafer 10 and the polishing pad 64 is set to a predetermined value. At this time, the air that has reached the second rotary joint 100 from the electropneumatic fixed-side pipe 73 flows from the eighth joint J8 to the upper fixed-side fluid passage 122 of the upper mechanical seal 120 and the upper rotation-side fluid of the second rotor 110. It passes through the passage 111 and reaches the electropneumatic rotary side pipe 67.

  Then, the electric motors M1 and M3 are driven to swing the polishing head 30 in the XY direction (in-plane direction of the contact surface between the wafer 10 and the polishing pad 64). At the same time, the slurry (abrasive) is pumped from the slurry supply device 80 to the slurry fixed side pipe 71 and the slurry rotation side pipe 65 (via the first rotary joint 90) and polished from the slurry supply hole 46. Slurry is supplied to the lower surface side of the pad 64. Thus, the surface 10s to be polished of the wafer 10 is polished by the rotational movement of the wafer 10 itself and the rotation and swinging movement of the polishing head 30 (that is, the polishing pad 64) while being supplied with the abrasive.

  When performing such polishing, pure water is supplied from the second pure water supply unit 86 to the first rotary joint 90 through the pure water supply pipe 74. Here, a seal space (not shown) provided in the first rotary joint 90 is filled with pure water, and cooling and lubrication of the seal surface in the mechanical seal of the first rotary joint 90 and the first rotary joint 90 are performed. A fluid (slurry) is sealed through.

  The pure water supplied to the first rotary joint 90 is supplied to the second rotary joint 100 through the pure water relay pipe line 75. Here, the seal space S provided in the second rotary joint 100 is filled with pure water, cooling and lubrication of the seal surface in each mechanical seal of the second rotary joint 100, and fluid passing through the second rotary joint 100 ( Air or pure water) is sealed. Then, the pure water supplied to the second rotary joint 100 is discharged to the drain port 87 through the pure water drain line 76.

  Further, once every two days or whenever the polishing pad 64 (pad plate 62) is replaced, a part of pure water passing through the pure water relay pipe 75 is provided in the pure water relay pipe 75. The specific gravity of pure water fed from the 75a to the hydrometer 88 and supplied to the first rotary joint 90 is measured by the hydrometer 88. Similarly, a part of the pure water passing through the pure water drain pipe 76 is sent to the hydrometer 88 from the branch part 76 a provided in the pure water drain pipe 76 and supplied to the second rotary joint 100 by the hydrometer 88. The specific gravity of the purified water is measured.

  The specific gravity of the pure water measured by the hydrometer 88 is within a reference range (for example, for example, the mechanical seal of each rotary joint 90, 100 is abnormally worn and debris of the mechanical seal is mixed in the pure water in the seal space). If it falls outside the range of the original density of the pure water (± 3%), the operator determines that the rotary joint needs to be replaced. When the specific gravity of pure water supplied to the first rotary joint 90 is out of the reference range, the first rotary joint 90 is replaced, and the specific gravity of pure water supplied to the second rotary joint 100 is below the reference range. When it comes off, the second rotary joint 100 is exchanged.

  As a result, according to the CMP apparatus 1 of the present embodiment, a hydrometer 88 that takes out part of the pure water supplied to the first and second rotary joints 90 and 100 and measures the specific gravity (physical properties) of the pure water. Therefore, it is possible to determine the replacement timing of each rotary joint 90, 100 according to the specific gravity of pure water measured by the hydrometer 88. Moreover, since the physical property of pure water can be known comparatively easily by using the hydrometer 88, it becomes possible to determine the replacement time of each rotary joint 90,100 with a simple configuration.

  In the above-described embodiment, the specific gravity of the pure water supplied to the first and second rotary joints 90 and 100 is measured using the hydrometer 88, but is not limited thereto. For example, a fine particle counter 89 may be used in place of the hydrometer 88 as indicated by a two-dot chain line in FIG. The fine particle counter 89 is an apparatus disclosed in, for example, Japanese Patent Laid-Open No. 5-149865, and is configured to measure the number of fine particles made of SiC (silicon carbide) contained in pure water. Thereby, the number of pieces of the mechanical seal made of SiC contained in pure water can be measured.

  Further, once every two days or whenever the polishing pad 64 (pad plate 62) is replaced, a part of pure water passing through the pure water relay pipe 75 is provided in the pure water relay pipe 75. The number of fine particles made of SiC (the number of mechanical seal fragments) contained in the pure water that is sent from 75a to the fine particle counter 89 and supplied to the first rotary joint 90 is measured by the fine particle counter 89. Similarly, a part of the pure water passing through the pure water drain pipe 76 is sent to the fine particle counter 89 from a branch part 76 a provided in the pure water drain pipe 76, and supplied to the second rotary joint 100 by the fine particle counter 89. The number of fine particles made of SiC contained in the purified water is measured.

  If the number of fine particles (number of mechanical seal fragments) measured by the fine particle counter 89 exceeds a predetermined reference value, the operator determines that the rotary joint needs to be replaced. When the number of fine particles contained in the pure water supplied to the first rotary joint 90 (the number of mechanical seal fragments) exceeds a reference value, the first rotary joint 90 is replaced and the second rotary joint 100 is replaced. When the number of the fine particles contained in the pure water supplied to exceeds the reference value, the second rotary joint 100 is replaced. By using the fine particle counter 89 in this way, the number of mechanical seal fragments can be measured, so that it is possible to more accurately determine the replacement time of each rotary joint 90, 100.

  In the above-described embodiment, the physical properties (specific gravity, the number of pieces of mechanical seals, etc.) of pure water supplied to the first and second rotary joints 90 and 100 are measured. However, the present invention is not limited to this. However, the present invention can be applied to any configuration that supplies liquid to the rotary joint for cooling and lubrication of the seal surface, sealing, and the like.

1 is a front view of a CMP apparatus which is an example of a polishing apparatus according to the present invention. It is a front sectional view showing the vicinity of the polishing head.

Explanation of symbols

1 CMP equipment (polishing equipment)
DESCRIPTION OF SYMBOLS 10 Wafer (Polishing object) 10s Polishing surface 26 3rd stage (Rotating holding member) 29 Spindle 30 Polishing head (Rotating member) 32 Head housing 60 Polishing member 61 Carrier member 62 Pad plate 63 Plate member 64 Polishing pad 64s Polishing surface 65 Slurry side pipe 66 Adsorption rotation side pipe 67 Electropneumatic rotation side pipe 71 Slurry fixed side pipe 72 Adsorption fixed side pipe 73 Electropneumatic fixed side pipe 88 Hydrometer (Physical property measurement) 89) Fine particle counter (physical property measuring device)
90 1st rotary joint 100 2nd rotary joint

Claims (3)

A polishing member capable of polishing an object to be polished;
A rotatable member that holds the polishing member and is rotatable;
A rotation holding member for rotatably holding the rotation member;
A rotary joint that connects the pipe provided in the rotation holding member and the pipe provided in the rotary member;
In a polishing apparatus configured to polish the polishing object by relatively moving the polishing member in contact with the polishing object,
The rotary joint is configured so that at least a liquid used for cooling the rotary joint is supplied from the outside.
A polishing apparatus comprising a physical property measuring device for taking out at least part of the liquid supplied to the rotary joint and measuring the physical property of the liquid.   The polishing apparatus according to claim 1, wherein the physical property measuring device is a hydrometer that measures the specific gravity of the liquid.   2. The polishing apparatus according to claim 1, wherein the physical property measuring device is a fine particle counter that measures the number of pieces of a seal member constituting the rotary joint contained in the liquid.

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