Polishing apparatus

Abstract

To suppress reduction in suction force of a holding surface.SOLUTION: By supplying the processing liquid 84 to the holding surface 22 of the chuck table 20 that does not hold a wafer, manganese dioxide adhering to and remaining at an outer circumferential portion or the like of the holding surface 22 can be removed. As a result, it is possible to suppress a reduction in the suction force of the holding surface 22 due to manganese dioxide, and to make the suction force of the holding surface 22 uniform. Accordingly, in the polishing step, the wafer can be uniformly held under suction on the holding surface 22, so that the wafer can be uniformly polished.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a polishing apparatus. [Background technology]

[0002] As disclosed in Patent Document 1, in the polishing process of wafers made of SiC or GaN, for example, an aqueous solution containing permanganate and an acidic inorganic salt is supplied to react Si in the SiC wafer to SiO2 or Ga in the GaN wafer to Ga2O3, thereby promoting polishing.

[0003] This reaction ionizes the permanganate to form manganese dioxide, which adheres to the outer periphery of the wafer. For this reason, as disclosed in Patent Document 2, a processing solution containing an acidic inorganic salt, hydrogen peroxide, and water is supplied from a polishing pad to clean the wafer and remove the manganese dioxide adhering to the outer periphery of the wafer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-253259 [Patent Document 2] Japanese Patent Publication No. 2022-185746 Summary of the Invention [Problem to be solved by the invention]

[0005] However, after the wafer is released, manganese dioxide has entered the holding surface and the porous member, which may reduce the suction holding force of the outer periphery of the holding surface.

[0006] Therefore, an object of the present invention is to suppress a decrease in the suction force of the holding surface by using a mechanism for cleaning the chuck table when polishing a wafer while supplying an aqueous solution containing permanganate and an acidic inorganic salt. [Means for solving the problem]

[0007] The polishing apparatus of the present invention (the present polishing apparatus) is a polishing apparatus comprising: a chuck table that suction-holds a wafer using a holding surface on the surface of a porous member; a polishing mechanism that polishes the wafer using a polishing pad while supplying a polishing liquid containing permanganate and an acidic inorganic salt to the wafer held by suction on the chuck table; a polishing liquid supply unit that supplies the polishing liquid to the wafer; and a control unit.The polishing apparatus comprises a processing liquid supply mechanism that supplies a processing liquid containing an acidic inorganic salt, hydrogen peroxide, and water to the chuck table to remove manganese dioxide generated when the wafer is polished using the polishing liquid.The control unit removes the manganese dioxide from the holding surface by supplying the processing liquid to the holding surface that is not holding a wafer using the processing liquid supply mechanism.

[0008] The polishing apparatus may be provided with a rotation mechanism that rotates the chuck table around the center of the holding surface as an axis, and the control unit may rotate the chuck table using the rotation mechanism while supplying the processing liquid to the center of the holding surface using the processing liquid supply mechanism.

[0009] In the polishing apparatus, the processing liquid supply mechanism may include a flow path that supplies the processing liquid to the porous member, and the control unit may cause the processing liquid supply mechanism to spray the processing liquid from the holding surface. [Effects of the Invention]

[0010] In this polishing apparatus, the control unit supplies a processing liquid to the holding surface of the chuck table that is not holding a wafer, thereby removing manganese dioxide remaining on the holding surface. This makes it possible to suppress a decrease in the suction force of the holding surface due to manganese dioxide and to make the suction force of the holding surface uniform. Therefore, the wafer can be uniformly suction-held by the holding surface, enabling uniform polishing of the wafer. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a perspective view showing the configuration of a polishing apparatus. [Figure 2] FIG. 10 is an explanatory diagram showing a support surface cleaning step. [Figure 3] FIG. 10 is an explanatory diagram showing a support surface cleaning step. [Figure 4] 10A and 10B are explanatory views showing another support surface cleaning step. [Figure 5] 10A and 10B are explanatory views showing another support surface cleaning step. DETAILED DESCRIPTION OF THE INVENTION

[0012] 1, the polishing apparatus 1 according to this embodiment is an apparatus for polishing a wafer 100. The wafer 100 is a semiconductor wafer made of, for example, SiC or GaN, and has a front surface 101 and a back surface 102. The back surface 102 of the wafer 100 is the surface to be polished.

[0013] As shown in FIG. 1, the polishing apparatus 1 has a first apparatus base 10 and a second apparatus base 11 disposed behind the first apparatus base 10 (on the +Y direction side).

[0014] A first cassette stage 160 and a second cassette stage 162 are provided on the −Y direction side of the first equipment base 10. A first cassette 3 and a second cassette 4, each containing a plurality of wafers 100, are placed on the first cassette stage 160 and the second cassette stage 162, respectively.

[0015] In the polishing apparatus 1, the openings 5 ​​of the first cassette 3 and the second cassette 4 face the +Y direction. A robot 155 is disposed on the +Y direction side of these openings. The robot 155 carries (stores) the processed wafers 100 into the first cassette 3 or the second cassette 4. The robot 155 also removes the unprocessed wafers 100 from the first cassette 3 or the second cassette 4 and places them on the temporary placement table 154 of the temporary placement mechanism 152.

[0016] The temporary placement mechanism 152 is used to temporarily place the wafer 100 taken out from the first cassette 3 or the second cassette 4, and is provided at a position adjacent to the robot 155. The temporary placement mechanism 152 has a temporary placement table 154 and an alignment member 153.

[0017] The alignment member 153 includes a plurality of alignment pins arranged on the outside so as to surround the temporary placement table 154, and a slider that moves the alignment pins in the radial direction of the temporary placement table 154. In the alignment member 153, the alignment pins are moved toward the center in the radial direction of the temporary placement table 154, thereby reducing the diameter of a circle connecting the plurality of alignment pins. As a result, the wafer 100 placed on the temporary placement table 154 is aligned (centered) at a predetermined position.

[0018] A carry-in mechanism 170 is provided at a position adjacent to the temporary placement mechanism 152. The carry-in mechanism 170 places the wafer 100 temporarily placed on the temporary placement mechanism 152 on the holding surface 22 of the chuck table 20 with the back surface 102 facing upward.

[0019] An opening 13 is provided on the upper surface side of the second apparatus base 11. Inside the opening 13, a wafer holding mechanism 30 is disposed.

[0020] The wafer holding mechanism 30 includes a chuck table 20 having a holding surface 22 that holds the wafer 100, a chuck table base 29 that supports the chuck table 20, a rotation mechanism 26 connected to the chuck table base 29 via an endless belt 25, a support member 28 that supports the chuck table base 29, and a plurality of support pillars 27 that support the support member 28.

[0021] 2, the chuck table 20 includes a porous member 21 and a frame 23 that houses the porous member 21 so that the surface of the porous member 21 is exposed. The surface of the porous member 21 is a holding surface 22 that holds the wafer 100 by suction. The holding surface 22 is connected to a suction source 530, thereby holding the wafer 100 by suction. In this way, the chuck table 20 holds the wafer 100 by suction using the holding surface 22 on the surface of the porous member 21.

[0022] Furthermore, a frame surface 24 which is the upper surface of the frame 23 surrounds the holding surface 22 and is formed so as to be on the same plane (flush) as the holding surface 22 .

[0023] The rotation mechanism 26 is configured to rotatably support the chuck table 20 and to rotate the chuck table 20 around the center of the holding surface 22 as an axis.

[0024] The rotation mechanism 26 is, for example, a pulley mechanism, and includes a rotating shaft 265 connected to the bottom of the chuck table base 29, a motor 261 serving as a driving source, a driving pulley 262 attached to the shaft of the motor 261, and a driven pulley 263 connected to the driving pulley 262 via an endless belt 25 and also connected to the rotating shaft 265.

[0025] In the rotation mechanism 26, the motor 261 rotates the drive pulley 262, thereby rotating the endless belt 25 and rotating the driven pulley 263, the rotating shaft 265, and the chuck table base 29. As a result, the chuck table 20 supported by the chuck table base 29 rotates as shown by the arrow 601, around a rotation axis passing through the center of the holding surface 22.

[0026] The rotation mechanism 26 also has an encoder 264. The encoder 264 is rotated by the motor 261 rotating the chuck table 20, and can recognize the amount of rotation of the chuck table 20 (the number of rotations and the rotation angle).

[0027] The polishing apparatus 1 also includes a fluid distribution mechanism 50. The fluid distribution mechanism 50 is a mechanism for supplying a fluid such as air or water to the holding surface 22 of the chuck table 20, and is also a mechanism for applying a suction force to the holding surface 22.

[0028] The fluid distribution mechanism 50 includes a suction flow path 51 , a rotary joint 52 connected to the lower end of the rotary shaft 265 , and a suction pipe 531 communicating with the suction flow path 51 .

[0029] The suction flow path 51 extends from the bottom surface of the porous member 21 so as to pass through the frame 23 , the chuck table base 29 , the rotary shaft 265 and the rotary joint 52 .

[0030] The suction pipe 531 is connected to one end of the suction flow path 51 outside the rotary joint 52, and is connected to the bottom of the porous member 21 of the chuck table 20 via these. The other end of the suction pipe 531 is connected to a suction source 530 via a suction on-off valve 532.

[0031] The suction source 530 includes a vacuum generating device such as a vacuum pump or an ejector mechanism, and is connected to the porous member 21 of the chuck table 20 to apply suction force to the upper surface, i.e., the holding surface 22. The suction on-off valve 532 is used to switch the communication state between the porous member 21 (holding surface 22) and the suction source 530.

[0032] Furthermore, an air pipe 541 is connected to the suction pipe 531. One end of the air pipe 541 is connected to the bottom of the porous member 21 of the chuck table 20 via the suction pipe 531 and the suction flow path 51. The other end of the air pipe 541 is connected to an air supply source 540 via an air supply opening / closing valve 542.

[0033] The air supply source 540 includes a compressor or the like, and is connected to the porous member 21 of the chuck table 20 to supply air to the holding surface 22. The air supply opening / closing valve 542 is used to switch the communication state between the porous member 21 (holding surface 22) and the air supply source 540.

[0034] Furthermore, a water pipe 551 is connected to the air pipe 541. One end of the water pipe 551 is connected to the bottom of the porous member 21 of the chuck table 20 via the air pipe 541, the suction pipe 531, and the suction flow path 51. A water supply source 550 is connected to the other end of the water pipe 551 via a water supply opening / closing valve 552.

[0035] The water supply source 550 includes a pump or the like, and is connected to the porous member 21 of the chuck table 20 to supply water to the holding surface 22. The water supply opening / closing valve 552 is used to switch the communication state between the porous member 21 (holding surface 22) and the water supply source 550.

[0036] By supplying air and / or water to the holding surface 22 through these air pipes 541 and / or water pipes 551, it becomes easier to separate the wafer 100 held on the holding surface 22 from the holding surface 22.

[0037] 1, a cover plate 39 that moves in the Y-axis direction together with the chuck table 20 is provided around the periphery of the chuck table 20. A bellows cover 12 that expands and contracts in the Y-axis direction is connected to the cover plate 39. A Y-axis direction moving mechanism 40 is disposed below the wafer holding mechanism 30.

[0038] The Y-axis direction moving mechanism 40 moves the chuck table 20 and the polishing pad 77 of the polishing mechanism 70 relatively in the Y-axis direction parallel to the holding surface 22. In this embodiment, the Y-axis direction moving mechanism 40 is configured to move the chuck table 20 in the Y-axis direction relative to the polishing pad 77.

[0039] The Y-axis direction movement mechanism 40 includes a pair of Y-axis guide rails 42 parallel to the Y-axis direction, a Y-axis movement table 45 that slides on these Y-axis guide rails 42, a Y-axis ball screw 43 parallel to the Y-axis guide rails 42, a Y-axis motor 44 connected to the Y-axis ball screw 43, and a holder 41 that holds these.

[0040] The Y-axis moving table 45 is slidably installed on the Y-axis guide rail 42. A nut portion (not shown) is fixed to the Y-axis moving table 45. A Y-axis ball screw 43 is threadedly engaged with this nut portion. The Y-axis motor 44 is connected to one end of the Y-axis ball screw 43.

[0041] In the Y-axis direction moving mechanism 40, the Y-axis motor 44 rotates the Y-axis ball screw 43, thereby moving the Y-axis moving table 45 in the Y-axis direction along the Y-axis guide rails 42. The wafer holding mechanism 30 is placed on the Y-axis moving table 45. Therefore, as the Y-axis moving table 45 moves in the Y-axis direction, the wafer holding mechanism 30 including the chuck table 20 moves in the Y-axis direction.

[0042] In this embodiment, the wafer holding mechanism 30 is moved along the Y-axis direction by the Y-axis movement mechanism 40 between a wafer holding position on the -Y direction side for holding the wafer 100 on the holding surface 22 of the chuck table 20 and a polishing position on the +Y direction side where the wafer 100 held on the holding surface 22 is polished.

[0043] Furthermore, a column 15 is erected on the −X direction side of the second apparatus base 11. In front of the column 15, a polishing mechanism 70 for polishing the wafer 100 and a vertical movement mechanism 60 are provided.

[0044] The vertical movement mechanism 60 moves the chuck table 20 and the polishing pad 77 of the polishing mechanism 70 relatively in the Z-axis direction, which is perpendicular to the holding surface 22. In this embodiment, the vertical movement mechanism 60 is configured to move the polishing pad 77 in the Z-axis direction relative to the chuck table 20.

[0045] The vertical movement mechanism 60 includes a fixed plate 67 fixed to the column 15, a pair of Z-axis guide rails 61 fixed to the fixed plate 67 and parallel to the Z-axis direction, a Z-axis movement table 63 that slides on the Z-axis guide rails 61, a Z-axis ball screw 62 parallel to the Z-axis guide rails 61, a Z-axis motor 64, and a holder 66 attached to the Z-axis movement table 63. The holder 66 supports a polishing mechanism 70.

[0046] The Z-axis moving table 63 is slidably installed on the Z-axis guide rail 61. A nut portion (not shown) is fixed to the Z-axis moving table 63. A Z-axis ball screw 62 is threadedly engaged with this nut portion. A Z-axis motor 64 is connected to one end of the Z-axis ball screw 62.

[0047] In the vertical movement mechanism 60, the Z-axis motor 64 rotates the Z-axis ball screw 62, causing the Z-axis movement table 63 to move in the Z-axis direction along the Z-axis guide rail 61. As a result, the holder 66 attached to the Z-axis movement table 63 and the polishing mechanism 70 supported by the holder 66 also move in the Z-axis direction together with the Z-axis movement table 63.

[0048] The polishing mechanism 70 polishes the wafer 100 with a polishing pad 77 while supplying a polishing liquid containing permanganate, an acidic inorganic salt, and water to the wafer 100 held by suction on the chuck table 20. The polishing mechanism 70 includes a spindle housing 71 fixed to the holder 66, a spindle 72 rotatably held by the spindle housing 71, a spindle motor 73 that rotates and drives the spindle 72, a wheel mount 74 attached to the lower end of the spindle 72, and a polishing wheel 75 supported by the wheel mount 74.

[0049] The spindle housing 71 is held by the holder 66 so as to extend in the Z-axis direction. The spindle 72 extends in the Z-axis direction so as to be perpendicular to the holding surface 22 of the chuck table 20, and is rotatably supported by the spindle housing 71.

[0050] The spindle motor 73 is connected to the upper end side of the spindle 72. The spindle motor 73 rotates the spindle 72 about a rotation axis extending in the Z-axis direction.

[0051] The wheel mount 74 is formed in a disk shape and is fixed to the lower end (tip) of the spindle 72. The wheel mount 74 supports the grinding wheel 75.

[0052] The grinding wheel 75 is formed to have an outer diameter that is approximately the same as the outer diameter of the wheel mount 74. The grinding wheel 75 includes a wheel base 76 that is connected to the lower surface of the wheel mount 74.

[0053] A polishing pad 77 is provided on the underside of the wheel base 76. The polishing pad 77 is made of, for example, nonwoven fabric such as felt. The underside of the polishing pad 77 serves as a polishing surface for polishing the backside 102 of the wafer 100. The polishing pad 77 is rotated around its center by the spindle motor 73 together with the spindle 72, and polishes the backside 102 of the wafer 100 held on the chuck table 20.

[0054] The polishing mechanism 70 also has a polishing liquid supply port 78 for supplying a polishing liquid to the polishing pad 77. The polishing liquid supply port 78 is connected to a polishing liquid supply source 201.

[0055] During polishing with the polishing pad 77, the polishing liquid is supplied from the polishing liquid supply source 201 to a polishing liquid supply path (not shown) in the spindle 72 via the polishing liquid supply port 78. This allows the polishing liquid to be supplied between the back surface 102, which is the surface to be polished of the wafer 100, and the lower surface of the polishing pad 77.

[0056] As described above, in this embodiment, the polishing liquid supply source 201, the polishing liquid supply port 78, and the polishing liquid supply path in the spindle 72 function as a polishing liquid supply unit that supplies the polishing liquid to the wafer 100. In addition, in this embodiment, the polishing liquid contains permanganate, an acidic inorganic salt, and water.

[0057] The outer diameters of the polishing wheel 75 and the polishing pad 77 are designed to be larger than the outer diameter of the wafer 100. Therefore, when the wafer 100 is polished by the polishing pad 77, there is a portion of the underside (polishing surface) of the polishing pad 77 that protrudes from the wafer 100. The polishing apparatus 1 may have a polishing liquid nozzle instead of or in addition to the polishing liquid supply port 78. When the wafer 100 is polished by the polishing pad 77, the polishing liquid nozzle sprays a polishing liquid onto the portion of the underside of the polishing pad 77 that protrudes from the wafer 100.

[0058] The polished wafer 100 is transferred by the transfer mechanism 172 from the chuck table 20 to the spinner table 157 of the spinner cleaning mechanism 156 .

[0059] The spinner cleaning mechanism 156 is a single-wafer type spinner cleaning unit that cleans the wafer 100. The spinner cleaning mechanism 156 includes a spinner table 157 that holds the wafer 100, and a nozzle 158 that sprays cleaning water and dry air toward the spinner table 157.

[0060] In the spinner cleaning mechanism 156, a spinner table 157 holding the wafer 100 rotates, and cleaning water is sprayed toward the wafer 100 to clean the wafer 100. Dry air is then blown onto the wafer 100 to dry the wafer 100.

[0061] The wafer 100 cleaned by the spinner cleaning mechanism 156 is carried by the robot 155 into the first cassette 3 or the second cassette 4 (for example, the cassette from which the wafer 100 was removed).

[0062] The polishing apparatus 1 also includes a first processing liquid supply mechanism 80 that supplies a processing liquid containing an acidic inorganic salt, hydrogen peroxide, and water to the wafer 100 and / or the chuck table 20. The processing liquid is used to remove manganese dioxide generated when the wafer 100 is polished with the polishing liquid. The first processing liquid supply mechanism 80 includes a processing liquid supply nozzle 81 that is disposed near the chuck table 20 on the second apparatus base 11, a processing liquid source 82 that is connected to the processing liquid supply nozzle 81, and a processing liquid valve 83 that connects these.

[0063] Furthermore, the polishing apparatus 1 has therein a control unit 7 for controlling the polishing apparatus 1. The control unit 7 includes a CPU that performs calculations according to a control program, and a storage medium such as a memory. The control unit 7 executes various processes and controls each component of the polishing apparatus 1.

[0064] For example, the control unit 7 controls the above-mentioned components of the polishing apparatus 1 to perform the polishing process on the wafer 100.

[0065] The polishing process according to this embodiment will be described below. [Holding process] First, a holding step is performed. In this step, the control unit 7 controls the robot 155 to take out the unprocessed wafer 100 from the first cassette 3 or the second cassette 4, place it on the temporary placement table 154 of the temporary placement mechanism 152, and align the wafer 100 at a predetermined position.

[0066] Furthermore, the control unit 7 controls the carry-in mechanism 170 to hold the wafer 100 on the temporary placement mechanism 152 and place the wafer 100 with the back surface 102 facing up on the holding surface 22 of the chuck table 20 located at the wafer holding position on the -Y direction side. Thereafter, the control unit 7 opens the suction on-off valve 532 of the fluid distribution mechanism 50 shown in FIG. 2 to connect the suction source 530 to the holding surface 22, thereby suction-holding the wafer 100 by the holding surface 22.

[0067] Furthermore, the control unit 7 controls the Y-axis direction moving mechanism 40 shown in FIG. 1 to place the wafer holding mechanism 30 including the chuck table 20 at the polishing position below the polishing mechanism 70 on the +Y direction side.

[0068] [Polishing process] After the holding step, the polishing step is performed. In this step, the control unit 7 rotates the polishing pad 77 using the spindle motor 73 of the polishing mechanism 70, and rotates the chuck table 20 using the rotation mechanism 26 of the wafer holding mechanism 30. Then, the control unit 7 controls the vertical movement mechanism 60 to feed the polishing mechanism 70, including the polishing pad 77, in the -Z direction for polishing. As a result, the rotating polishing pad 77 comes into contact with the back surface 102 of the wafer 100 held on the rotating chuck table 20, polishing the back surface 102. This polishing step is performed, for example, for a predetermined period of time.

[0069] In the polishing step, the control unit 7 controls the polishing liquid supply source 201 to supply the polishing liquid to the polishing liquid supply path in the spindle 72 via the polishing liquid supply port 78. This allows the polishing liquid to be supplied approximately uniformly between the back surface 102 of the wafer 100 and the lower surface of the polishing pad 77.

[0070] The polishing solution according to this embodiment contains permanganate, an acidic inorganic salt, and water, and is acidic overall. In the polishing process, if the wafer 100 is made of SiC, the polishing solution has a chemical effect of converting Si in the wafer 100 into SiO2. If the wafer 100 is made of GaN, the polishing solution has a chemical effect of converting Ga in the wafer 100 into GaO2.

[0071] As a result, in the polishing process, the mechanical action of the abrasive grains of the polishing pad 77 and the chemical action of the polishing liquid work together to polish the back surface 102 of the wafer 100 well so that it becomes flat.

[0072] In the polishing process, since the polishing liquid contains permanganate, an acidic inorganic salt, and water, manganese dioxide (MnO2) is generated by polishing the back surface 102 of the wafer 100 with the polishing pad 77. This manganese dioxide may adhere to and remain on, for example, the outer periphery of the holding surface 22 of the chuck table 20 (around the wafer 100).

[0073] [Export process] After the polishing step, the unloading step is performed. In this step, the control unit 7 controls the Y-axis direction moving mechanism 40 to place the wafer holding mechanism 30 including the chuck table 20 at the wafer holding position on the −Y direction side.

[0074] 2 to cut off communication between the porous member 21 and the suction source 530, and opens the air supply on-off valve 542 and the water supply on-off valve 552 to connect the air supply source 540 and the water supply source 550 to the porous member 21. As a result, a mixed fluid of water and air is sprayed from the holding surface 22, which is the upper surface of the porous member 21, and the suction force of the holding surface 22 holding the wafer 100 is eliminated.

[0075] 1 to hold the wafer 100 on the chuck table 20 and place the wafer 100 on the spinner table 157 of the spinner cleaning mechanism 156. After the spinner cleaning mechanism 156 cleans the wafer 100, the control unit 7 controls the robot 155 to remove the wafer 100 from the spinner cleaning mechanism 156 and load it into the first cassette 3 or the second cassette 4.

[0076] [Retention surface cleaning process] After the carrying-out step, a holding surface cleaning step is performed in which the control unit 7 controls the first processing liquid supply mechanism 80 to supply a processing liquid to the holding surface 22 of the chuck table 20 that is not holding a wafer 100, thereby removing manganese dioxide from the holding surface 22.

[0077] At this time, the control unit 7 controls the first processing liquid supply mechanism 80 to supply the processing liquid to the center of the holding surface 22, while controlling the rotation mechanism 26 to rotate the chuck table 20.

[0078] Specifically, the control unit 7 first controls the Y-axis direction moving mechanism 40 to place the wafer holding mechanism 30 including the chuck table 20 at a polishing position on the +Y direction side. Thereafter, the control unit 7 rotates the processing liquid supply nozzle 81 of the first processing liquid supply mechanism 80 to position the tip of the processing liquid supply nozzle 81 at the center of the holding surface 22 that is not holding the wafer 100, as shown in FIG. 2, and then opens the processing liquid valve 83. This connects the processing liquid supply nozzle 81 to the processing liquid source 82, and the processing liquid 84 is sprayed from the tip of the processing liquid supply nozzle 81 toward the center of the holding surface 22.

[0079] Furthermore, the control unit 7 causes the rotation mechanism 26 of the wafer holding mechanism 30 to rotate the chuck table 20 that is not holding the wafer 100, as shown by the arrow 601. As a result, the processing liquid 84 supplied to the center of the holding surface 22 spreads over the entire back surface 102 due to centrifugal force, and is discharged outside the back surface 102 from its outer periphery.

[0080] As described above, in this embodiment, the treatment solution contains an acidic inorganic salt, hydrogen peroxide, and water, and is acidic overall. In this embodiment, the concentration of hydrogen peroxide is, for example, 1% or more, e.g., about 3%. The pH value of the treatment solution is, for example, 3.0 or less.

[0081] Since the treatment liquid 84 contains an acidic inorganic salt, hydrogen peroxide, and water, the manganese dioxide remaining on the support surface 22 is reduced to water-soluble manganese (Mn 2+ ) and water (HO).

[0082] Next, for example, after a predetermined time has elapsed since the start of spraying the treatment liquid 84, the control unit 7 closes the treatment liquid valve 83 of the first treatment liquid supply mechanism 80 to stop spraying of the treatment liquid 84 from the treatment liquid supply nozzle 81. Then, as shown in FIG. 3, the control unit 7 rotates the treatment liquid supply nozzle 81 to retract it from above the holding surface 22, and opens the water supply on-off valve 552 of the fluid distribution mechanism 50. As a result, the water supply source 550 is connected to the porous member 21, and water 85 is sprayed from the holding surface 22, which is the upper surface of the porous member 21. The water 85 spreads over the entire surface of the holding surface 22 due to centrifugal force, and is discharged from the outer periphery of the holding surface 22 to the outside. At this time, manganese (Mn 2+ ) dissolves in water 85 and is removed from the support surface 22.

[0083] Thereafter, the control unit 7 stops the rotation of the chuck table 20 by the rotation mechanism 26 and closes the water supply opening / closing valve 552, thereby completing the holding surface cleaning process.

[0084] As described above, in this embodiment, the control unit 7 supplies the processing liquid 84 to the holding surface 22 of the chuck table 20 that is not holding a wafer 100, thereby making it possible to remove manganese dioxide remaining on the outer periphery and other portions of the holding surface 22. This makes it possible to suppress a decrease in the suction force of the holding surface 22 due to manganese dioxide, and to make the suction force of the holding surface 22 uniform. Therefore, in the polishing process, the wafer 100 can be uniformly suction-held by the holding surface 22, making it possible to polish the wafer 100 uniformly.

[0085] 1, the first processing liquid supply mechanism 80 includes a processing liquid supply nozzle 81 provided near the chuck table 20, and supplies a processing liquid 84 from above to the holding surface 22. In this regard, the processing liquid supply mechanism according to the present embodiment may be provided in the fluid distribution mechanism 50.

[0086] That is, in this configuration, as shown in Fig. 4, the fluid distribution mechanism 50 includes a second treatment liquid supply mechanism 56 in addition to the configuration shown in Fig. 2. The second treatment liquid supply mechanism 56 includes a treatment liquid supply source 560, a treatment liquid pipe 561, and a treatment liquid supply open / close valve 562.

[0087] The processing liquid pipe 561 is a flow path that supplies the processing liquid to the porous member 21. One end of the processing liquid pipe 561 is connected to the bottom of the porous member 21 of the chuck table 20 via a water pipe 551, an air pipe 541, a suction pipe 531, and a suction flow path 51. The other end of the processing liquid pipe 561 is connected to a processing liquid supply source 560 via a processing liquid supply opening / closing valve 562.

[0088] The processing liquid supply source 560 includes a pump and the like, and is used to supply the processing liquid to the holding surface 22 of the chuck table 20. The processing liquid supply opening / closing valve 562 is used to switch the communication state between the porous member 21 (holding surface 22) and the processing liquid supply source 560.

[0089] When such a second processing liquid supply mechanism 56 is used, the control unit 7 causes the second processing liquid supply mechanism 56 to spray the processing liquid from the holding surface 22 in the holding surface cleaning step.

[0090] 4, after the carrying-out step, the control unit 7 keeps the suction on-off valve 532, the air supply on-off valve 542, and the water supply on-off valve 552 in the fluid distribution mechanism 50 closed, while opening the treatment liquid supply on-off valve 562 in the second treatment liquid supply mechanism 56. This places the porous member 21 in communication with the treatment liquid supply source 560, and causes the treatment liquid 84 to spray from the holding surface 22, which is the upper surface of the porous member 21.

[0091] Furthermore, the control unit 7 causes the rotation mechanism 26 of the wafer holding mechanism 30 to rotate the chuck table 20 that is not holding the wafer 100, as shown by the arrow 601. As a result, the processing liquid 84 ejected from the holding surface 22 spreads over the entire surface of the holding surface 22 due to centrifugal force, and is discharged outside the holding surface 22 from its outer periphery.

[0092] At this time, since the treatment liquid 84 contains an acidic inorganic salt, hydrogen peroxide, and water, the manganese dioxide remaining on the support surface 22 is reduced to water-soluble manganese (Mn 2+ ) and water (HO).

[0093] Next, after a predetermined time has elapsed since the start of spraying of the treatment liquid 84, the control unit 7 closes the treatment liquid supply on-off valve 562 of the second treatment liquid supply mechanism 56, as shown in FIG. 5, to stop the spraying of the treatment liquid 84 from the holding surface 22. Then, the control unit 7 opens the water supply on-off valve 552 of the fluid distribution mechanism 50. As a result, the water supply source 550 is connected to the porous member 21, and water 85 is sprayed from the holding surface 22, which is the upper surface of the porous member 21. The water 85 spreads over the entire surface of the holding surface 22 due to centrifugal force, and is discharged from the outer periphery of the holding surface 22 to the outside. At this time, manganese (Mn 2+ ) dissolves in water 85 and is removed from the support surface 22.

[0094] Thereafter, the control unit 7 stops the rotation of the chuck table 20 by the rotation mechanism 26 and closes the water supply opening / closing valve 552, thereby completing the holding surface cleaning process.

[0095] 4 and 5 is used, the control unit 7 can supply the processing liquid 84 to the holding surface 22 of the chuck table 20 that is not holding a wafer 100, thereby removing manganese dioxide remaining on the outer periphery of the holding surface 22. This makes it possible to suppress a decrease in the suction force of the holding surface 22 due to manganese dioxide, and to make the suction force of the holding surface 22 uniform. Therefore, in the polishing process, the wafer 100 can be uniformly suction-held by the holding surface 22, thereby enabling the wafer 100 to be polished uniformly.

[0096] 4 and 5, in the holding surface cleaning step using the second processing liquid supply mechanism 56, the processing liquid 84 from the processing liquid supply source 560 and the water 85 from the water supply source 550 are sprayed from almost the entire surface of the holding surface 22. Therefore, it is not necessary to rotate the chuck table 20 by the rotation mechanism 26.

[0097] In this embodiment, the holding surface cleaning step is performed after the polishing step of polishing the wafer 100 and the unloading step of unloading the wafer 100. In this regard, the holding surface cleaning step may be performed before polishing the wafer 100, that is, before the holding step of holding the wafer 100 by the chuck table 20.

[0098] Furthermore, in the polishing step, manganese dioxide may adhere not only to the holding surface 22 but also to the back surface 102, which is the surface to be polished, of the wafer 100. For this reason, after the polishing step and before the wafer 100 is removed from the holding surface 22, a processing liquid may be supplied to the back surface 102 of the wafer 100 by the first processing liquid supply mechanism 80 shown in FIG. 2 to reduce the manganese dioxide adhered to the back surface 102 to water-soluble manganese and remove it (residue cleaning step).

[0099] In this case, a rotating polishing pad 77 may be brought into contact with the back surface 102 of the rotating wafer 100, and a processing liquid may be supplied between the polishing pad 77 and the back surface 102. In this case, the processing liquid may be supplied to the back surface 102 of the wafer 100 using a polishing liquid supply path in the spindle 72. This makes it possible to effectively remove manganese dioxide adhering to the wafer 100. [Explanation of symbols]

[0100] 1: polishing device, 3: first cassette, 4: second cassette, 5: opening, 7: control unit, 10: first device base; 11: second device base; 12: bellows cover; 13: opening, 15: column, 20: chuck table, 21: porous member, 22: holding surface, 23: frame body, 24: frame body surface, 25: endless belt, 26: rotation mechanism, 27: Support column, 28: Support member, 29: Chuck table base, 30: wafer holding mechanism, 39: cover plate, 40: Y-axis direction moving mechanism, 41: Support table, 42: Y-axis guide rail, 43: Y-axis ball screw, 44: Y-axis motor, 45: Y-axis moving table, 50: fluid distribution mechanism, 51: suction flow path, 52: rotary joint, 56: second processing liquid supply mechanism, 60: vertical movement mechanism, 61: Z-axis guide rail, 62: Z-axis ball screw, 63: Z-axis moving table, 64: Z-axis motor, 66: holder, 67: fixing plate, 70: polishing mechanism, 71: spindle housing, 72: spindle, 73: spindle motor, 74: Wheel mount, 75: Grinding wheel, 76: Wheel base, 77: polishing pad, 78: polishing liquid supply port, 80: first processing liquid supply mechanism, 81: Processing liquid supply nozzle, 82: Processing liquid source, 83: Processing liquid valve, 84: Processing liquid, 85: water, 100: wafer, 101: front surface, 102: back surface, 152: temporary placement mechanism, 153: Alignment member, 154: Temporary placement table, 155: Robot, 156: Spinner cleaning mechanism, 157: Spinner table, 158: Nozzle, 160: first cassette stage, 162: second cassette stage, 170: loading mechanism, 172: Discharge mechanism, 201: Polishing liquid supply source, 261: Motor, 262: Drive pulley, 263: driven pulley, 264: encoder, 265: rotating shaft, 530: suction source, 531: suction piping, 532: suction on-off valve, 540: air supply source, 541: air piping, 542: air supply opening / closing valve, 550: water supply source, 551: water piping, 552: water supply opening / closing valve, 560: Processing liquid supply source, 561: Processing liquid piping, 562: Processing liquid supply opening / closing valve

Claims

1. a chuck table that suction-holds the wafer using a holding surface on the surface of a porous member; a polishing mechanism that polishes the wafer with a polishing pad while supplying a polishing liquid containing a permanganate and an acidic inorganic salt to the wafer held by suction on the chuck table; a polishing liquid supply unit that supplies the polishing liquid to the wafer; A polishing apparatus comprising: a processing liquid supply mechanism for supplying to the chuck table a processing liquid containing an acidic inorganic salt, hydrogen peroxide, and water for removing manganese dioxide generated when the wafer is polished with the polishing liquid; the control unit removes the manganese dioxide from the holding surface by supplying the processing liquid to the holding surface that is not holding a wafer using the processing liquid supply mechanism. Polishing equipment.

2. a rotation mechanism that rotates the chuck table around an axis that is the center of the holding surface; the control unit controls the rotation mechanism to rotate the chuck table while supplying the processing liquid to the center of the holding surface using the processing liquid supply mechanism; The polishing apparatus according to claim 1.

3. the treatment liquid supply mechanism includes a flow path that supplies the treatment liquid to the porous member; the control unit causes the treatment liquid supply mechanism to eject the treatment liquid from the holding surface; The polishing apparatus according to claim 1.

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