Polishing head, polishing apparatus equipped with the same, and substrate processing apparatus

Abstract

To increase a removal ratio of dust associated with polishing.SOLUTION: Dust generated in a rear surface of a substrate due to polishing by a polishing tool 96 is pushed even to an outer peripheral side of the polishing tool 96 due to a centrifugal force. Nitrogen gas is injected thereto from an injection port 235. As a result, the dust adhered to a rear surface of the substrate is separated from the rear surface of the substrate. The dust is sucked by a suction port 237. Accordingly, the dust is hard to be accumulated in the rear surface of the substrate, so that a removal rate of dust associated with polishing can be increased.SELECTED DRAWING: Figure 13

Description

[Technical Field]

[0001] The present invention relates to a polishing head for polishing the backside of a substrate, a polishing apparatus equipped with the same, and a substrate processing apparatus. Examples of substrates include semiconductor substrates, substrates for FPDs (Flat Panel Displays), glass substrates for photomasks, substrates for optical disks, substrates for magnetic disks, ceramic substrates, and substrates for solar cells. Examples of FPDs include liquid crystal displays and organic electroluminescence (EL) displays. Here, the backside of a substrate refers to the side on which no electronic circuits are formed, as opposed to the front side of the substrate, which is the side on which electronic circuits are formed. [Background technology]

[0002] BACKGROUND ART There is a polishing apparatus for polishing the rear surface of a substrate that includes a polishing head that includes a polishing tool, a head body, a recess, and a suction hole (see, for example, Patent Document 1).

[0003] The polishing tool is equipped with a synthetic grinding stone. The synthetic grinding stone is formed by fixing abrasive material (abrasive grains) with a resin binder. The synthetic grinding stone is molded in a circular ring shape. The head body holds the polishing tool. The recess has an opening facing the back surface of the substrate. A suction hole is formed in the head body, communicates with the recess, and is connected to a suction pump. Polishing using this polishing head is dry chemical mechanical grinding, also known as CMG (chemo-mechanical grinding).

[0004] In a polishing machine using such a polishing head, the center of the polishing tool is sucked through the suction hole in the polishing head. Therefore, dust generated by polishing with the polishing tool is sucked through the suction hole by the suction pump. As a result, processing can be performed with minimal dust remaining on the substrate surface. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2020-4948 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the conventional example having such a configuration has the following problems. In recent years, there has been a problem with defocusing (so-called out-of-focus) in EUV (Extreme Ultraviolet) exposure equipment due to the substrate flatness of the backside of the substrate (e.g., wafer). The causes of poor flatness are thought to be particles, scratches, film residue, etc. Therefore, the removal of these by using a polishing head is being considered.

[0007] However, conventional polishing heads only suck the central portion. As a result, some of the dust generated near the periphery of the polishing tool may not be removed by suction and may remain attached to the substrate surface. As a result, the defocusing problem remains, which may adversely affect post-polishing processing. In other words, there is a problem that the rate at which dust is removed from the substrate surface during polishing is low.

[0008] The present invention has been made in consideration of the above circumstances, and aims to provide a polishing head that can increase the rate of dust removal during polishing, and a polishing apparatus and substrate processing apparatus equipped with the same. [Means for solving the problem]

[0009] In order to achieve the above object, the present invention has the following configuration. That is, the invention described in claim 1 is a polishing head for polishing a substrate, comprising a polishing tool having a resin body in which abrasive grains are dispersed, an injection port for injecting gas into dust generated by polishing with the polishing tool, and a suction port for sucking in the dust generated by polishing with the polishing tool. The injection port is provided along the outer peripheral surface of the grinding tool, and the suction port is provided along the outer peripheral surface of the grinding tool and is provided line-symmetrically with the injection port in a plan view. It is characterized by the fact that

[0010] [Action and Effect] According to the invention described in claim 1, gas is sprayed from the spray nozzle onto the dust generated by polishing with the polishing tool. This causes the dust adhering to the substrate surface to detach from the substrate surface. The dust is then sucked up by the suction port. Therefore, dust is less likely to remain on the substrate surface, and the dust removal rate during polishing can be increased.

[0012] The outer periphery of the grinding tool is divided into line-symmetrical sections in a plan view, with each section serving as an injection port and a suction port. This allows for a good balance between gas supply and suction on the outer periphery of the grinding tool, which in turn allows for good dust removal.

[0013] Also, A polishing head for polishing a substrate comprises a polishing tool having a resin body in which abrasive grains are dispersed, an injection port for injecting gas onto dust generated by polishing with the polishing tool, and a suction port for sucking in the dust generated by polishing with the polishing tool, The grinding tool is provided in an annular shape in a plan view, the injection port is provided in the center of the grinding tool, and the suction port is provided around the entire outer periphery of the grinding tool. Ru( Claim 2 ).

[0014] The gas jetted from the center is directed toward the outer periphery of the polishing tool on the substrate surface, so that the gas containing dust can be efficiently sucked in by the suction port.

[0015] Also, A polishing head for polishing a substrate comprises a polishing tool having a resin body in which abrasive grains are dispersed, an injection port for injecting gas onto dust generated by polishing with the polishing tool, and a suction port for sucking in the dust generated by polishing with the polishing tool, The grinding tool is made of a porous material with holes that communicate with each other, the injection port is provided on the bottom surface of the grinding tool, and the suction port is provided around the entire outer periphery of the grinding tool. Ru( Claim 3 ).

[0016] Gas is supplied to the polishing tool made of a porous material, and the gas can be sprayed onto the dust from almost the entire lower surface, thereby efficiently pushing the dust out to the periphery.

[0017] In the present invention, it is preferable that the injection port injects gas discontinuously (see claim 4 ).

[0018] If gas is sprayed continuously, the dust particles may be pressed against the substrate surface and may not be able to be removed. Therefore, if gas is sprayed discontinuously and intermittently, the dust particles can be more easily removed.

[0019] Also, claims 5 The invention described in claim 1 is a polishing apparatus for polishing a substrate, 4 a head drive mechanism for rotating the polishing head around a vertical axis; a holding and rotating unit for rotating the substrate while holding the substrate in a horizontal position; a gas supply pipe for supplying gas to an injection port of the polishing head; and a suction pipe for suctioning from a suction port of the polishing head.

[0020] [Action / Effect] Claim 5 According to the invention described in the above, the polishing head is rotated around a vertical axis by a head drive mechanism. The substrate is rotated in a horizontal position by a holding / rotating unit. In this state, the polishing tool of the polishing head is brought into contact with the substrate surface to perform polishing. During this process, gas is supplied to the polishing head through a gas supply pipe, causing dust adhering to the substrate surface to detach from the substrate surface. Furthermore, the dust is sucked together with the gas through a suction pipe by a suction port. Therefore, dust is less likely to remain on the substrate surface, thereby increasing the dust removal rate during polishing.

[0021] In addition, in the present invention, it is preferable that the polishing apparatus further comprises a control valve for controlling the flow of gas in the gas supply pipe and a control unit for operating the control valve, and the control unit operates the control valve so that gas is sprayed intermittently from the polishing head (see claim 1). 6 ).

[0022] If gas is sprayed continuously, the dust particles may be pressed against the substrate surface and may not be able to be removed. Therefore, the control unit operates the control valve to discontinuously spray the gas from the polishing head. Discontinuous, intermittent gas spraying makes it easier to remove the dust particles.

[0023] In the present invention, it is preferable that the control unit operates the control valve so that the flow rate of the gas injected from the injection port does not exceed the flow rate of the gas sucked from the suction pipe (see claim 7 ).

[0024] By controlling the flow rate in this manner, it is possible to prevent dust particles from being sucked through the suction port due to the gas being ejected from the ejection port, and from scattering around.

[0025] Also, claims 8 The substrate processing apparatus according to claim 5 to 7 The present invention is characterized in that it is equipped with the polishing apparatus according to any one of the above.

[0026] [Action / Effect] Claim 8 According to the invention described in the above, when a substrate is polished in a polishing apparatus, the polishing head is rotated about a vertical axis by a head drive mechanism. The substrate is rotated in a horizontal position by a holding / rotating unit. In this state, the polishing tool of the polishing head is brought into contact with the substrate surface to perform polishing. During this process, gas is supplied to the polishing head through a gas supply pipe, causing dust adhering to the substrate surface to detach from the substrate surface. Furthermore, the dust is sucked together with the gas through a suction pipe by a suction port. Therefore, dust is less likely to remain on the substrate surface, thereby increasing the dust removal rate during polishing. As a result, the substrate can be processed cleanly. [Effects of the Invention]

[0027] With the polishing head according to the present invention, gas is sprayed from the nozzle onto dust generated during polishing with a polishing tool. This causes dust adhering to the substrate surface to detach from the substrate surface. The dust is then sucked up by the suction port. This makes it difficult for dust to remain on the substrate surface, thereby increasing the rate at which dust is removed during polishing. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a plan view showing a configuration of a substrate processing apparatus according to a first embodiment. [Figure 2] 10(a) to 10(d) are diagrams for explaining the reversing unit. [Figure 3] FIG. 2 is a side view showing the configuration of a polishing unit. [Figure 4]1A is a plan view showing the configuration of the holding and rotating part, and FIG. 1B is a vertical cross-sectional view showing a part of the configuration of the holding and rotating part in an enlarged manner. [Figure 5] FIG. 2 is a diagram showing the configuration of a polishing mechanism of a polishing unit. [Figure 6] FIG. 2 is a diagram showing the configuration of an inspection unit. [Figure 7] 4 is a flowchart showing the operation of the substrate processing apparatus according to the first embodiment. [Figure 8] (a) is a longitudinal cross-sectional view schematically showing the substrate before the etching process, (b) is a longitudinal cross-sectional view schematically showing the substrate after the etching process (before the back surface polishing process), and (c) is a longitudinal cross-sectional view schematically showing the substrate after the back surface polishing process. [Figure 9] 10 is a flowchart showing details of a wet etching process. [Figure 10] FIG. 10 is a diagram showing the relationship between the heating temperature of the substrate and the polishing rate. [Figure 11] 10 is a flowchart showing the details of a substrate cleaning process. [Figure 12] 10A and 10B are diagrams showing a preferred configuration of a polishing mechanism of a polishing unit. [Figure 13] FIG. 2 is a vertical cross-sectional view of the polishing head according to the first embodiment. [Figure 14] FIG. 2 is a bottom view of the polishing head according to the first embodiment. [Figure 15] FIG. 10 is a vertical cross-sectional view of a polishing head according to a second embodiment. [Figure 16] FIG. 10 is a bottom view of the polishing head according to the second embodiment. [Figure 17] FIG. 10 is a vertical cross-sectional view of a polishing head according to a third embodiment. [Figure 18] FIG. 10 is a bottom view of the polishing head according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0029] The present invention will now be described with reference to the following examples. [Example]

[0030] A first embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a plan view showing the configuration of a substrate processing apparatus according to the first embodiment.

[0031] (1) Configuration of the substrate processing equipment Referring to Fig. 1, the substrate processing apparatus 1 includes an indexer block 3 and a processing block 5. The blocks are also called regions.

[0032] The indexer block 3 includes a plurality of (for example, four) carrier mounting tables 7 and an indexer robot 9. The four carrier mounting tables 7 are arranged on the outer surface of a housing 10. Each of the four carrier mounting tables 7 mounts a carrier C. The carrier C stores a plurality of substrates W. Each substrate W in the carrier C is in a horizontal position with its device surface facing upward (upward). The carrier C may be, for example, a FOUP (Front Open Unified Pod), an SMIF (Standard Mechanical Interface Face), or an open cassette. The substrate W is a silicon substrate, and is formed, for example, in a disk shape.

[0033] The indexer robot 9 takes out substrates W from carriers C placed on each carrier placement table 7 and stores substrates W in carriers C. The indexer robot 9 is disposed inside a housing 10. The indexer robot 9 has two hands 11 (11A, 11B), two articulated arms 13, 14, a lifting table 15, and a guide rail 16. Each of the two hands 11 holds a substrate W. The first hand 11A is connected to the tip of the articulated arm 13. The second hand 11B is connected to the tip of the articulated arm 14.

[0034] Each of the two articulated arms 13, 14 is configured, for example, as a SCARA type. The base end of each of the two articulated arms 13, 14 is attached to a lifting platform 15. The lifting platform 15 is configured to be extendable and retractable in the vertical direction. This allows the two hands 11 and the two articulated arms 13, 14 to be raised and lowered. The lifting platform 15 is rotatable around a central axis AX1 extending in the vertical direction. This allows the orientation of the two hands 11 and the two articulated arms 13, 14 to be changed. The lifting platform 15 of the indexer robot 9 is movable along a guide rail 16 extending in the Y direction.

[0035] The indexer robot 9 is equipped with a plurality of electric motors and is driven by the plurality of electric motors. The indexer robot 9 transports substrates W between the carriers C placed on each of the four carrier placement tables 7 and a reversing unit RV, which will be described later.

[0036] The processing block 5 includes a transport space 18, a substrate transport robot CR, a reversing unit RV, and multiple (e.g., eight) processing units (processing chambers) U1 to U4. In FIG. 1, the processing units U1 to U4 are configured, for example, in two layers in the vertical direction. The processing unit U1 is an inspection unit 20. The processing units U2, U3, and U4 are polishing units 22. The number and types of processing units can be changed as appropriate.

[0037] A substrate transport robot CR and a reversing unit RV are disposed in the transport space 18. The reversing unit RV is disposed between the indexer robot 9 and the substrate transport robot CR. The processing units U1 and U3 are disposed side by side in the X direction along the transport space 18. Furthermore, the processing units U2 and U4 are disposed side by side in the X direction along the transport space 18. The transport space 18 is disposed between the processing units U1 and U3 and the processing units U2 and U4.

[0038] The substrate transport robot CR is configured in almost the same manner as the indexer robot 9. That is, the substrate transport robot CR has two hands 24. Other components of the substrate transport robot CR are denoted by the same reference numerals as those of the indexer robot 9. Unlike the lifting platform 15 of the indexer robot 9, the lifting platform 15 of the substrate transport robot CR is fixed to the floor surface. However, the lifting platform 15 of the substrate transport robot CR may be configured to include a guide rail extending in the X direction so as to be movable in the X direction. The substrate transport robot CR transports substrates W between the reversing unit RV and the eight processing units U1 to U4.

[0039] (1-1) Reversing unit RV 2(a) to 2(d) are diagrams illustrating the reversing unit RV. The reversing unit RV includes a support member 26, placement members 28A and 28B, clamping members 30A and 30B, a slide shaft 32, and a plurality of electric motors (not shown). Placement members 28A and 28B are provided on the left and right support members 26, respectively. Clamping members 30A and 30B are provided on the left and right slide shafts 32, respectively. The plurality of electric motors drive the support members 26 and the slide shafts 32. The placement members 28A and 28B and the clamping members 30A and 30B are positioned so as not to interfere with each other.

[0040] See FIG. 2(a). Substrates W transported by, for example, the indexer robot 9 are placed on the placement members 28A, 28B. See FIG. 2(b). The left and right slide shafts 32 move toward each other along the horizontal axis AX2. As a result, the clamping members 30A, 30B clamp the two substrates W. See FIG. 2(c). Thereafter, the left and right placement members 28A, 28B move downward while moving away from each other. Thereafter, the clamping members 30A, 30B rotate 180° around the horizontal axis AX2. As a result, each substrate W is inverted.

[0041] See Figure 2(d). Thereafter, the left and right mounting members 28A, 28B move upward while approaching each other. Then, the left and right slide shafts 32 move away from each other along the horizontal axis AX2. This releases the two substrates W from the clamping members 30A, 30B, and the two substrates W are placed on the mounting members 28A, 28B. In Figures 2(a) to 2(d), the reversing unit RV can reverse two substrates W, but the reversing unit RV may be configured to be able to reverse three or more substrates W.

[0042] (1-2) Polishing unit 22 3 is a diagram showing the polishing unit 22. The polishing unit 22 includes a holding and rotating unit 35, a polishing mechanism 37, and a substrate thickness measuring device 39.

[0043] The holding and rotating unit 35 holds one substrate W in a horizontal position with the back surface of the substrate W facing upward, and rotates the held substrate W. Here, the back surface of the substrate W refers to the surface on which no electronic circuits are formed, as opposed to the front surface of the substrate W, which is the surface on which electronic circuits are formed (device surface). The device surface of the substrate W held by the holding and rotating unit 35 faces downward.

[0044] The holding and rotating unit 35 includes a spin base 41, six holding pins 43, a hot plate 45, and a gas outlet 47. The spin base 41 is formed in a disk shape and is placed in a horizontal position. A rotation axis AX3 extending in the vertical direction passes through the center of the spin base 41. The spin base 41 is rotatable around the rotation axis AX3.

[0045] FIG. 4(a) is a plan view showing the spin base 41 and six holding pins 43 of the holding rotation unit 35. The six holding pins 43 are provided on the upper surface of the spin base 41. The six holding pins 43 are provided in a ring shape so as to surround the rotation axis AX3. The six holding pins 43 are also provided at equal intervals on the outer edge side of the spin base 41. The six holding pins 43 place the substrate W away from the spin base 41 and a hot plate 45, which will be described later. Furthermore, the six holding pins 43 are configured to sandwich the side surfaces of the substrate W. In other words, the six holding pins 43 can hold the substrate W away from the upper surface of the spin base 41.

[0046] The six holding pins 43 are divided into three holding pins 43A that rotate and three holding pins 43B that do not rotate. The three holding pins 43A are rotatable around a rotation axis AX4 that extends in the vertical direction. As each holding pin 43A rotates around the rotation axis AX4, the three holding pins 43A hold the substrate W and release the held substrate W. The rotation of each holding pin 43A around the rotation axis AX4 is achieved by, for example, magnetic attraction or repulsion force generated by a magnet. The number of holding pins 43 is not limited to six, and may be three or more. The substrate W may be held by three or more holding pins 43, including the rotating holding pins 43A and the non-rotating holding pins 43B.

[0047] A hot plate 45 is provided on the upper surface of the spin base 41. The hot plate 45 has an electric heater having, for example, nichrome wire inside. The hot plate 45 is formed in a donut shape and a disk shape. The hot plate 45 heats the substrate W with radiant heat. The hot plate 45 also heats the gas discharged from a gas discharge port 47 (described later), and thus heats the substrate W via the gas. The temperature of the substrate W is measured by a non-contact temperature sensor 46. The temperature sensor 46 has a detection element that detects infrared rays emitted by the substrate W.

[0048] A shaft 49 is provided on the underside of the spin base 41. The rotation mechanism 51 has an electric motor. The rotation mechanism 51 rotates the shaft 49 around a rotation axis AX3. That is, the rotation mechanism 51 rotates the substrate W held by six holding pins 43 (specifically, three holding pins 43A) provided on the spin base 41 around the rotation axis AX3.

[0049] 3 and 4(b), gas discharge port 47 is provided in the center of spin base 41, opening on the top surface thereof. A flow path 53 that opens upward is provided in the center of spin base 41. A discharge member 57 is provided in flow path 53 via a plurality of spacers 55. Gas discharge port 47 is a ring-shaped opening formed by the gap between discharge member 57 and flow path 53.

[0050] The gas supply pipe 59 is provided so as to penetrate the shaft 49 and the rotation mechanism 51 along the rotation axis AX3. The gas pipe 61 sends gas (for example, an inert gas such as nitrogen) from a gas supply source 63 to the gas supply pipe 59. The gas pipe 61 is provided with an on-off valve V1. The on-off valve V1 starts and stops the supply of gas. When the on-off valve V1 is in an open state, gas is discharged from the gas discharge port 47. When the on-off valve V1 is in a closed state, gas is not discharged from the gas discharge port 47. The gas discharge port 47 discharges gas in the gap between the substrate W and the spin base 41 so that the gas flows from the center of the substrate W to the outer edge of the substrate W.

[0051] Next, the configuration for supplying the chemical liquid, rinse liquid, and gas will be described. Polishing unit 22 includes first chemical liquid nozzle 65, second chemical liquid nozzle 67, first cleaning liquid nozzle 69, second cleaning liquid nozzle 71, rinse liquid nozzle 73, and gas nozzle 75.

[0052] Chemical liquid piping 78 for sending a first chemical liquid from a first chemical liquid supply source 77 is connected to first chemical liquid nozzle 65. The first chemical liquid is, for example, hydrofluoric acid (HF). Chemical liquid piping 78 is provided with an on-off valve V2. On-off valve V2 starts and stops the supply of the first chemical liquid. When on-off valve V2 is open, the first chemical liquid is supplied from first chemical liquid nozzle 65. When on-off valve V2 is closed, the supply of the first chemical liquid from first chemical liquid nozzle 65 stops.

[0053] A chemical pipe 81 for sending a second chemical from a second chemical supply source 80 is connected to the second chemical nozzle 67. The second chemical is, for example, a mixture of hydrofluoric acid (HF) and nitric acid (HNO), TMAH (tetramethylammonium hydroxide), or diluted hot ammonia water (hot-dNHOH). An on-off valve V3 is provided in the chemical pipe 81. The on-off valve V3 starts and stops the supply of the second chemical.

[0054] A cleaning liquid pipe 84 for sending the first cleaning liquid from a first cleaning liquid supply source 83 is connected to the first cleaning liquid nozzle 69. The first cleaning liquid is, for example, SC2 or SPM. SC2 is a mixture of hydrochloric acid (HCl), hydrogen peroxide (H2O2), and water. SPM is a mixture of sulfuric acid (H2SO4) and hydrogen peroxide water (H2O2). An on-off valve V4 is provided in the cleaning liquid pipe 84. The on-off valve V4 starts and stops the supply of the first cleaning liquid.

[0055] A cleaning liquid pipe 87 for sending a second cleaning liquid from a second cleaning liquid supply source 86 is connected to the second cleaning liquid nozzle 71. The second cleaning liquid is, for example, SC1. SC1 is a mixed liquid of ammonia, hydrogen peroxide (H2O2), and water. An on-off valve V5 is provided in the cleaning liquid pipe 87. The on-off valve V5 starts and stops the supply of the second cleaning liquid.

[0056] A rinse liquid pipe 90 for supplying the rinse liquid from a rinse liquid supply source 89 is connected to the rinse liquid nozzle 73. The rinse liquid is, for example, pure water such as DIW (Deionized Water) or carbonated water. An on-off valve V6 is provided in the rinse liquid pipe 90. The on-off valve V6 starts and stops the supply of the rinse liquid.

[0057] A gas pipe 93 for supplying gas from a gas supply source 92 is connected to the gas nozzle 75. The gas is an inert gas such as nitrogen. An on-off valve V7 is provided in the gas pipe 93. The on-off valve V7 starts and stops the supply of gas.

[0058] First chemical liquid nozzle 65 is moved in the horizontal direction by nozzle movement mechanism 95. Nozzle movement mechanism 95 includes an electric motor. Nozzle movement mechanism 95 may rotate first chemical liquid nozzle 65 around a preset vertical axis (not shown). Nozzle movement mechanism 95 may also move first chemical liquid nozzle 65 in the X direction and the Y direction. Nozzle movement mechanism 95 may also move first chemical liquid nozzle 65 in the up and down direction (Z direction). Like first chemical liquid nozzle 65, each of five nozzles 67, 69, 71, 73, and 75 may be moved by a nozzle movement mechanism (not shown).

[0059] Next, the configuration of the polishing mechanism 37 will be described. The polishing mechanism 37 polishes the back surface of the substrate W. Fig. 5 is a side view showing the polishing mechanism 37. The polishing mechanism 37 includes a polishing tool 96 and a polishing tool moving mechanism 97. The polishing tool moving mechanism 97 includes an attachment member 98, a shaft 100, and an arm 101.

[0060] The polishing tool (grinding tool) 96 polishes the back surface of the substrate W by dry chemical mechanical grinding (CMG). The polishing tool 96 is formed in a cylindrical shape. The polishing tool 96 has a resin body in which abrasive grains are dispersed. In other words, the polishing tool 96 is formed by fixing abrasive grains (abrasive material) with a resin binder. For example, an oxide such as cerium oxide or silica is used as the abrasive grains. The average particle size of the abrasive grains is preferably 10 μm or less. For example, a thermosetting resin such as an epoxy resin or a phenolic resin is used as the resin body and the resin binder. Alternatively, a thermoplastic resin such as ethyl cellulose may be used as the resin body and the resin binder. In this case, polishing is performed so as not to soften the thermoplastic resin.

[0061] Here, we will explain chemical mechanical grinding (CMG). CMG is believed to work according to the following principle: When abrasive grains such as cerium oxide come into contact with the workpiece, localized high temperatures and pressures are generated near the abrasive grains, causing a solid-phase reaction between the abrasive grains and the workpiece, producing silicates. As a result, the surface layer of the workpiece softens, and the softened surface layer is mechanically removed by the abrasive grains. There is also a polishing method called CMP (Chemical Mechanical Polishing). This method involves supplying a slurry solution to a pad that comes into contact with the workpiece, and then chemically mechanically polishing the workpiece by holding the abrasive grains contained in the slurry solution against the unevenness of the pad surface. The present invention employs the CMG method.

[0062] The grinding tool 96 is detachably attached to the attachment member 98, for example, by screws. The attachment member 98 is fixed to the lower end of a shaft 100. A pulley 102 is fixed to the shaft 100. The upper end side of the shaft 100 is housed in an arm 101. That is, the grinding tool 96 and the attachment member 98 are attached to the arm 101 via the shaft 100.

[0063] An electric motor 104 and a pulley 106 are disposed within the arm 101. The pulley 106 is connected to the rotary output shaft of the electric motor 104. A belt 108 is wound around the two pulleys 102 and 106. The pulley 106 is rotated by the electric motor 104. The rotation of the pulley 106 is transmitted to the pulley 102 and the shaft 100 by the belt 108. This causes the grinding tool 96 to rotate around the vertical axis AX5.

[0064] The polishing tool moving mechanism 97 further includes a lifting mechanism 110. The lifting mechanism 110 includes a guide rail 111, an air cylinder 113, and an electro-pneumatic regulator 115. The base end of the arm 101 is connected to the guide rail 111 so that it can be raised and lowered. The guide rail 111 guides the arm 101 in the up and down direction. The air cylinder 113 raises and lowers the arm 101. The electro-pneumatic regulator 115 supplies gas, such as air, to the air cylinder 113 at a pressure set based on an electric signal from a main control unit 134, which will be described later. The lifting mechanism 110 may include a linear actuator driven by an electric motor instead of the air cylinder 113.

[0065] Furthermore, the polishing tool moving mechanism 97 includes an arm rotating mechanism 117. The arm rotating mechanism 117 includes an electric motor. The arm rotating mechanism 117 rotates the arm 101 and the lifting mechanism 110 around a vertical axis AX6. That is, the arm rotating mechanism 117 rotates the polishing tool 96 around the vertical axis AX6.

[0066] The polishing unit 22 includes a substrate thickness measuring device 39. The substrate thickness measuring device 39 measures the thickness of the substrate W held by the holding / rotating unit 35. The substrate thickness measuring device 39 is configured to irradiate light in a wavelength range (e.g., 1100 nm to 1900 nm) that is transparent to the substrate W from a light source to a mirror and the substrate W via an optical fiber. The substrate thickness measuring device 39 is also configured to detect, with a light-receiving element, return light resulting from interference between the light reflected by the mirror, the light reflected from the upper surface of the substrate W, and the light reflected from the lower surface of the substrate W. The substrate thickness measuring device 39 is configured to generate a spectral interference waveform that indicates the relationship between the wavelength and light intensity of the return light, and to measure the thickness of the substrate W by waveform analysis of this spectral interference waveform. The substrate thickness measuring device 39 is a known device. The substrate thickness measuring device 39 may be configured to be moved between a standby position outside the substrate W and a measurement position above the substrate W by a moving mechanism (not shown).

[0067] (1-3) Inspection Unit 20 6 is a side view showing the inspection unit 20. The inspection unit 20 includes a stage 121, an XY direction movement mechanism 122, a camera 124, a light 125, a laser scanning confocal microscope 127, an elevation mechanism 128, and an inspection control unit 130.

[0068] The stage 121 supports the substrate W with its back surface facing upward and in a horizontal position. The stage 121 includes a disk-shaped base member 131 and, for example, six support pins 132. The six support pins 132 are arranged in a ring shape around the central axis AX7 of the base member 131. The six support pins 132 are also arranged at equal intervals in the circumferential direction. With this configuration, the six support pins 132 can support the outer edge of the substrate W while keeping the substrate W separated from the base member 131. The XY-direction movement mechanism 122 moves the stage 121 in the X and Y directions (horizontal directions). The XY-direction movement mechanism 122 includes, for example, two linear actuators each driven by an electric motor.

[0069] The camera 124 photographs the rear surface of the substrate W. The camera 124 includes an image sensor such as a charge-coupled device (CCD) or a complementary metal-oxide semiconductor (CMOS). The illumination 125 irradiates the rear surface of the substrate W with light. This makes it easier to observe scratches that have occurred on the rear surface of the substrate W, for example.

[0070] The laser scanning confocal microscope 127 will be referred to as the "laser microscope 127" hereinafter. The laser microscope 127 includes a confocal optical system having a laser light source, an objective lens 127A, an imaging lens, an optical sensor, and a confocal pinhole. The laser microscope 127 acquires a planar image by scanning the laser light source in the X and Y directions (horizontal directions). Furthermore, the laser microscope 127 acquires a planar image while moving the objective lens 127A in the Z direction (height direction) relative to the object being observed. As a result, the laser microscope 127 acquires a three-dimensional image (multiple planar images) including a three-dimensional shape. The laser microscope 127 will be referred to as a three-dimensional shape measuring device.

[0071] The laser microscope 127 acquires a three-dimensional image of any scratch that has occurred on the rear surface of the substrate W. For example, a control unit, which will be described later, measures the depth of the scratch from the three-dimensional shape of the scratch in the acquired three-dimensional image. The lifting mechanism 128 raises and lowers the laser microscope 127 in the vertical direction (Z direction). The lifting mechanism 128 is composed of a linear actuator driven by an electric motor.

[0072] The inspection control unit 130 includes one or more processors, such as a central processing unit (CPU), and a storage unit (not shown). The inspection control unit 130 controls each component of the inspection unit 20. The storage unit of the inspection control unit 130 includes at least one of a read-only memory (ROM), a random-access memory (RAM), and a hard disk. The storage unit of the inspection control unit 130 stores a computer program for operating the inspection unit 20, observed images, scratch extraction results, and three-dimensional images.

[0073] Furthermore, the substrate processing apparatus 1 includes a main control unit 134 and a storage unit (not shown) communicatively connected to the inspection control unit 130. The main control unit 134 includes one or more processors, such as a central processing unit (CPU). The main control unit 134 controls each component of the substrate processing apparatus 1. The storage unit of the main control unit 134 includes at least one of a read-only memory (ROM), a random-access memory (RAM), and a hard disk. The storage unit of the main control unit 134 stores computer programs and the like for operating the substrate processing apparatus 1.

[0074] (2) Operation of the substrate processing apparatus 1 Next, the operation of the substrate processing apparatus 1 will be described with reference to FIG.

[0075] [Step S01] Removal of substrate W from carrier C A carrier C is placed on a predetermined carrier mounting table 7. The indexer robot 9 takes out a substrate W from the carrier C and transports the taken-out substrate W to the reversing unit RV. At this time, the device surface of the substrate W faces upward, and the back surface of the substrate W faces downward.

[0076] [Step S02] Reversing the substrate W When one or two substrates W are placed on the placement members 28A and 28B by the indexer robot 9, the reversing unit RV reverses the two substrates W, as shown in Figures 2(a) to 2(d), so that the back surfaces of the substrates W face upward.

[0077] The substrate transport robot CR takes out the substrate W from the reversing unit RV and transports the substrate W to one of the two inspection units 20. The substrate W is placed with its back surface facing upward on the stage 121 of the inspection unit 20 shown in FIG.

[0078] [Step S03] Scratch observation The inspection unit 20 inspects the rear surface of the substrate W. The inspection unit 20 detects scratches, particles, and other protrusions. In this embodiment, the case of detecting scratches formed on the rear surface of the substrate W will be described in particular.

[0079] In the inspection unit 20 shown in FIG. 6, the illumination 125 irradiates light toward the back surface of the substrate W. The camera 124 captures an image of the back surface of the substrate W irradiated with light to obtain an observation image. The camera 124 may capture the image while moving the stage 121 on which the substrate W is placed using the XY direction movement mechanism 122. The obtained observation image shows scratches of various sizes. The inspection control unit 130 performs image processing on the observation image and extracts one or more scratches by determining that portions with relatively strong reflected light, i.e., portions having a brightness greater than a predetermined threshold, are to be polished. The inspection control unit 130 may also extract scratches on the polishing target based on the length of the scratch.

[0080] Furthermore, when a scratch is detected, the inspection unit 20 measures the depth of the scratch. For example, when a plurality of scratches are detected (extracted), the inspection unit 20 measures the depth of one or more representative scratches among them. The measurement of the scratch depth will be described below.

[0081] The lifting mechanism 128 (FIG. 6) lowers the laser microscope 127 to a preset height position. In addition, the XY-direction moving mechanism 122 moves the stage 121 so that the scratch to be measured is positioned below the objective lens 127A of the laser microscope 127. The movement of the stage 121 is performed based on the coordinates of the scratch extracted from the observation image. The laser microscope 127 irradiates the scratch (all or part) and its surroundings with laser light from the objective lens 127A, and collects reflected light through the objective lens 127A. As a result, the laser microscope 127 acquires a three-dimensional image including the three-dimensional shape.

[0082] The inspection control unit 130 performs image processing on the three-dimensional image and measures the depth of the scratch. FIG. 8(a) is a longitudinal sectional view for explaining the state of the substrate W before the etching process. In FIG. 8(a), for example, it is assumed that a thin film such as a silicon oxide film, a silicon nitride film, or polysilicon is formed on the back surface of the substrate W. It is also assumed that the scratch SH1 on the left side of FIG. 8(a) reaches the bare silicon BSi. In this case, the inspection control unit 130 measures the depth (value DP1) of the scratch SH1 from the three-dimensional image obtained by the laser microscope 127.

[0083] After observing for scratches and the like, the substrate transport robot CR transports the substrate W from the stage 121 of the inspection unit 20 to one of the six polishing units 22 (U2 to U4). The substrate W is placed with its back surface facing upward on the holding rotation part 35 of the polishing unit 22. Thereafter, a magnet (not shown) rotates the three holding pins 43A shown in FIG. 4(a) around the rotation axis AX4. As a result, the three holding pins 43A hold the substrate W. Here, the substrate W is held in a state spaced apart from the spin base 41 and the hot plate 45.

[0084] Here, before the next wet etching step, the substrate thickness measuring device 39 measures the thickness of the substrate W. The thickness TK1 of the substrate W as shown in Fig. 8(a) is obtained.

[0085] [Step S04] Wet etching If a thin film such as a silicon oxide film, a silicon nitride film, or a polysilicon film is formed on the back surface of the substrate W, the back surface of the substrate W cannot be polished well by the polishing tool 96. Some of these films are formed unintentionally during the device manufacturing process, while others are formed intentionally to suppress warpage of the substrate W. Therefore, the polishing unit 22 removes the film F1 formed on the back surface of the substrate W by supplying a first chemical liquid (etchant) to the back surface of the substrate W.

[0086] 9 is a flowchart for explaining the details of the wet etching process in step S04. First, a process for removing the silicon oxide film and the silicon nitride film is performed (step S21).

[0087] Here, gas is discharged from gas discharge port 47 provided in the center of spin base 41. That is, gas discharge port 47 discharges gas in the gap between substrate W and spin base 41 so that the gas flows from the center of substrate W to the outer edge of the substrate. The device surface (front surface) of substrate W faces spin base 41. When gas is discharged from gas discharge port 47, the gas is ejected to the outside from the gap between the outer edge of substrate W and spin base 41. This prevents liquids such as polishing debris and the first chemical liquid from adhering to the device surface of substrate W. That is, the device surface can be protected. Furthermore, due to the Bernoulli effect, a force acts to attract substrate W to spin base 41.

[0088] Nozzle moving mechanism 95 moves first chemical liquid nozzle 65 from a standby position outside the substrate to an arbitrary processing position above substrate W. Holding and rotating unit 35 rotates substrate W while holding substrate W in a horizontal position. Thereafter, first chemical liquid nozzle 65 supplies a first chemical liquid (e.g., hydrofluoric acid) to the rear surface of rotating substrate W. This makes it possible to remove the silicon oxide film and silicon nitride film formed on the rear surface of substrate W.

[0089] The first chemical liquid may be supplied while horizontally moving first chemical liquid nozzle 65. After the supply of the first chemical liquid from first chemical liquid nozzle 65 is stopped, first chemical liquid nozzle 65 is moved to a standby position outside the substrate.

[0090] Thereafter, a rinsing process is performed (step S22). That is, a rinsing liquid (e.g., DIW or carbonated water) is supplied from the rinsing liquid nozzle 73 to the center of the rotating substrate W. This causes the first chemical liquid remaining on the back surface of the substrate W to be washed away from the substrate. Thereafter, a drying process is performed (step S23). That is, the supply of the rinsing liquid from the rinsing liquid nozzle 73 is stopped. Then, the holding rotation unit 35 rotates the substrate W at high speed to dry the substrate W. At this time, gas may be supplied to the back surface of the substrate W from the gas nozzle 75 moved above the substrate W. Note that the drying process may be performed by supplying gas from the gas nozzle 75 without rotating the substrate W at high speed.

[0091] After steps S21 to S23, a process for removing the polysilicon film is performed (step S24). Second chemical liquid nozzle 67 is moved from a standby position outside the substrate W to an arbitrary processing position above the substrate W. Holding and rotating unit 35 rotates substrate W at a preset rotation speed. Thereafter, second chemical liquid nozzle 67 supplies a second chemical liquid (for example, a mixed liquid of hydrofluoric acid (HF) and nitric acid (HNO3)) to the rear surface of the rotating substrate W. This makes it possible to remove the polysilicon film formed on the rear surface of substrate W.

[0092] The second chemical liquid may be supplied while moving second chemical liquid nozzle 67 in the horizontal direction. After the supply of the second chemical liquid from second chemical liquid nozzle 67 is stopped, second chemical liquid nozzle 67 is moved to a standby position outside the substrate.

[0093] Thereafter, substantially similarly to the case of the first chemical liquid (steps S22 and S23), a rinsing process (step S25) is performed, and then a drying process (step S26) is performed. The holding and rotating part 35 stops the rotation of the substrate W.

[0094] [Step S05] Polishing the back surface of the substrate W After the etching step, the polishing unit 22 polishes the back surface of the substrate W. This polishing is performed when the inspection unit 20 detects scratches, in particular, on the back surface of the substrate W. This will be described in detail.

[0095] The holding and rotating unit 35 rotates the substrate W while holding it in a horizontal position. The arm rotation mechanism 117 (FIG. 5) of the polishing mechanism 37 rotates the polishing tool 96 and the arm 101 about a vertical axis AX6. This moves the polishing tool 96 from a standby position outside the substrate to a preset position above the substrate W. In addition, the electric motor 104 of the polishing mechanism 37 rotates the polishing tool 96 about the vertical axis AX5 (shaft 100).

[0096] Furthermore, the hot plate 45 generates heat when energized to heat the substrate W. The temperature of the substrate W is monitored by a non-contact temperature sensor 46. The main control unit 134 adjusts the heat generated by the hot plate 45 based on the temperature of the substrate W detected by the temperature sensor 46. The heating temperature of the substrate W is adjusted to a temperature higher than room temperature (e.g., 25°C) in order to obtain a high polishing rate. However, it is preferably adjusted to 100°C or less to avoid thermal deterioration of the polishing tool 96.

[0097] Thereafter, the electropneumatic regulator 115 supplies gas of a pressure based on the electric signal to the air cylinder 113. This causes the air cylinder 113 to lower the polishing tool 96 and arm 101, bringing the polishing tool 96 into contact with the back surface of the substrate W. The polishing tool 96 is pressed against the back surface of the substrate W with a preset contact pressure. In this way, polishing is performed. When polishing is performed, the arm rotation mechanism 117 (FIG. 5) of the polishing mechanism 37 oscillates the polishing tool 96 and arm 101 around the vertical axis AX6. That is, the polishing tool 96 repeatedly reciprocates, for example, between a position on the center side of the back surface of the substrate W and a position on the outer edge side.

[0098] Regarding the amount of polishing in the thickness direction (Z direction) of the substrate W, even if scratches are present, polishing may seem unnecessary if the substrate W meets a preset flatness. However, there is a risk that the edges of the scratches may create new scratches on, for example, the stage of an exposure machine. Therefore, polishing is continued until scratches of a preset size are removed.

[0099] As shown in FIG. 8(a), the depth (value DP1) of the scratch SH1 was acquired by the laser microscope 127. Therefore, the polishing unit 22 polishes the back surface of the substrate W until a thickness corresponding to the depth (value DP1) of the scratch SH1 measured by the laser microscope 127 is removed. The thickness corresponding to the depth of the scratch SH1 is value DP1. Polishing is continued until the thickness of the substrate W reaches value TK2 (=TK1-DP1). The thickness of the substrate W is periodically measured by the substrate thickness measuring device 39. The main control unit 134 compares the measured value of the substrate thickness with a target value (e.g., value TK2), and if the measured value does not reach the target value, controls to continue polishing.

[0100] FIG. 8(b) shows the state after the etching step (step S04). When the film FL is removed by the etching step, the depth of the scratch SH1 becomes shallower. Therefore, the amount of polishing in the vertical direction decreases, but the substrate W is still polished to a thickness of value TK2. FIG. 8(c) shows the state after the polishing step (step S05). Note that the scratch SH2 shown in FIG. 8(a) does not reach the bare silicon. Such scratches are removed when the film FL, such as a silicon oxide film, is removed.

[0101] The substrate W is heated by the hot plate 45. FIG. 10 is a diagram showing the relationship between the heating temperature of the substrate W and the polishing rate. The contact pressure of the polishing tool 96 and the rotation speed of the substrate W are constant. Here, for example, if the temperature TM2 of the substrate W is increased compared to when the temperature of the substrate W is room temperature (e.g., 25°C), the polishing rate increases. Therefore, by heating the substrate W with the hot plate 45, the polishing rate can be increased. As a result, the polishing process time can be shortened.

[0102] When polishing, the polishing unit 22 may adjust the polishing rate by controlling the heating temperature of the substrate W by the hot plate 45. The polishing rate can be increased or decreased by increasing or decreasing the heating temperature of the substrate W. The polishing rate may be adjusted before or during polishing. For example, by changing the temperature of the substrate W between the center side and the outer edge side of the substrate W, the polishing rate can be made different between the center side and the outer edge side of the substrate W. The polishing tool 96 is moved to a standby position for the substrate W.

[0103] [Step S06] Cleaning the substrate W After polishing the rear surface of the substrate W, the rear surface of the substrate W is cleaned. This removes polishing debris remaining on the rear surface of the substrate W, as well as metals, organic substances, and particles. Figure 11 is a flowchart showing the details of the cleaning process in step S06.

[0104] First, a first cleaning liquid is supplied to the rear surface of the substrate W (step S31). A more detailed explanation will be given. The holding and rotating unit 35 continues to hold the substrate W. The holding and rotating unit 35 also continues to protect the device surface of the substrate W by discharging gas from the gas outlet 47. The first cleaning liquid nozzle 69 is moved from a standby position outside the substrate to an arbitrary processing position above the substrate W. The holding and rotating unit 35 rotates the substrate W. Thereafter, the first cleaning liquid nozzle 69 supplies a first cleaning liquid (e.g., SC2 or SPM) to the rear surface of the rotating substrate W. The first cleaning liquid may be supplied while the first cleaning liquid nozzle 69 is moved horizontally.

[0105] After the first cleaning liquid is supplied and the cleaning process is performed, a rinsing process is performed (step S32). That is, a rinsing liquid (DIW or carbonated water) is supplied from the rinsing liquid nozzle 73 to the center of the rotating substrate W. This washes away the first cleaning liquid remaining on the back surface of the substrate W. Thereafter, a drying process is performed (step S33). That is, the supply of the rinsing liquid from the rinsing liquid nozzle 73 is stopped. Then, the holding and rotating unit 35 dries the substrate W by rotating the substrate W at high speed. At this time, gas may be supplied to the back surface of the substrate W from the gas nozzle 75 moved above the substrate W. Note that the drying process may be performed by supplying gas from the gas nozzle 73 without rotating the substrate W at high speed.

[0106] After steps S31 to S33, the second cleaning liquid is supplied (step S34). That is, the second cleaning liquid nozzle 71 is moved from a standby position outside the substrate W to an arbitrary processing position above the substrate W. The holding and rotating unit 35 rotates the substrate W at a preset rotation speed. Thereafter, the second cleaning liquid nozzle 71 supplies the second cleaning liquid (e.g., SC1) to the rear surface of the rotating substrate W.

[0107] The second cleaning liquid may be supplied while horizontally moving the second cleaning liquid nozzle 71. After the supply of the second cleaning liquid from the second cleaning liquid nozzle 71 is stopped, the second cleaning liquid nozzle 71 is moved to a standby position outside the substrate.

[0108] Thereafter, a rinsing process (step S35) is performed in substantially the same manner as in the case of the first cleaning liquid (steps S32 and S33), and then a drying process (step S36) is performed. The holding and rotating part 35 stops the rotation of the substrate W. Since the polishing unit 22 in this embodiment has a cleaning function, the substrate W from which polishing debris has been cleaned can be carried out from the polishing unit 22.

[0109] [Step S07] Reversing the substrate W The substrate transport robot CR takes out the substrate W from the polishing unit 22 and transports the substrate to the reversing unit RV. At this time, the back surface of the substrate W faces upward, and the device surface of the substrate W faces downward. When one or two substrates W are placed on the mounting members 28A, 28B by the substrate transport robot CR, the reversing unit RV reverses the two substrates W, as shown in FIGS. 2(a) to 2(d). As a result, the back surfaces of the substrates W face downward.

[0110] [Step S08] Place the substrate W in the carrier C The indexer robot 9 takes the substrate W out of the reversing unit RV and returns the substrate W to the carrier C.

[0111] According to this embodiment, the polishing unit 22 includes a holding / rotating part 35, a hot plate 45 (heating means), and a polishing tool 96. The polishing tool 96 comes into contact with the rear surface of the rotating substrate W and polishes the rear surface of the substrate W by chemical mechanical grinding (CMG). When this polishing is performed, the substrate W is heated by the hot plate 45. When the substrate W is heated, the polishing rate can be increased (see FIG. 10). Therefore, the polishing process time can be shortened.

[0112] Furthermore, the inspection unit 20 that inspects the substrate W detects scratches formed on the back surface of the substrate W before polishing the back surface of the substrate W. Furthermore, when a scratch is detected, the inspection unit 20 polishes the back surface of the substrate W. This makes it possible to remove the detected scratches, i.e., the selected scratches.

[0113] Furthermore, when a scratch is detected, the inspection unit 20 measures the depth of the scratch. The polishing unit 22 polishes the rear surface of the substrate W until a thickness corresponding to the depth of the scratch measured by the inspection unit 20 is removed. This allows the depth of the scratch to be recognized, making it possible to appropriately polish the amount of substrate W in the thickness direction.

[0114] (1-4) Polishing head 201

[0115] A preferred configuration of the above-mentioned polishing mechanism 37 will now be described with reference to Fig. 12. Fig. 12 is a diagram showing a preferred configuration of the polishing mechanism of the polishing unit.

[0116] The polishing mechanism 37A differs in configuration from the above-described polishing mechanism 37 in the following points.

[0117] A polishing head 201 is attached to the attachment member 98. The polishing head 201 includes a polishing tool 96.

[0118] The shaft 100 to which the mounting member 98 is attached includes a gas supply pipe 203 and a suction pipe 205 therein. The gas supply pipe 203 and the suction pipe 205 are arranged side by side within the shaft 100. The gas supply pipe 203 and the suction pipe 205 are inserted into the shaft 100. The gas supply pipe 203 and the suction pipe 205 are connected in communication with a rotary joint 207. The rotary joint 207 includes a fixed-side body 209 and a rotating-side body 211. The fixed-side body 209 is fixed to the arm 101. The rotating-side body 211 is attached to the shaft 100. The rotary joint 207 allows at least two fluids to flow between the fixed-side body 209 fixed to the arm 101 and the rotating-side body 211 that rotates together with the shaft 100.

[0119] One end of the gas supply pipe 203 extending from the rotary joint 207 is connected in communication with a gas supply source 213. The gas supply source 213 supplies a gas. The gas is preferably an inert gas. The inert gas is, for example, nitrogen gas. The gas supply pipe 203 is equipped with a flow rate adjustment valve 215 and an on-off valve 217. The flow rate adjustment valve 215 adjusts the flow rate of the gas flowing through the gas supply pipe 203. The on-off valve 217 allows or blocks the flow of gas through the gas supply pipe 203.

[0120] One end of the suction pipe 205 extending from the rotary joint 207 is connected in communication with a suction source 219. The suction source 219 sucks the inside of the suction pipe 205. The suction source 219 sucks gas. The suction source 219 is, for example, a suction pump or a suction utility provided in a clean room. The suction pipe 205 is equipped with an on-off valve 221. The on-off valve 221 allows or blocks the flow of gas through the suction pipe 205.

[0121] The above-mentioned on-off valves 217 and 221 and the flow rate adjusting valve 215 are operated by the main control unit 134.

[0122] 13 and 14 are referenced here. Fig. 13 is a vertical cross-sectional view of the polishing head according to Example 1. Fig. 14 is a bottom view of the polishing head according to Example 1.

[0123] The polishing head 201 includes a polishing tool 96, a head body 223, and a cover 225. The polishing tool 96 is attached to the underside of the head body 223. The head body 223 is formed with a first flow path 227 and a second flow path 229. The first flow path 227 and the second flow path 229 are not connected to each other. The first flow path 227 and the second flow path 229 connect the upper surface and the outer circumferential surface of the head body 223. The first flow path 227 has openings 231 formed at, for example, three locations on the outer circumferential surface of the head body 223. The second flow path 229 has openings 233 formed at, for example, three locations on the outer circumferential surface of the head body 223. The first flow path 227 and the second flow path 229 are preferably formed to be line-symmetrical with respect to a line passing through the vertical axis AX5 in a plan view.

[0124] The cover 225 is attached to the head main body 223. The cover 225 is attached to the outer peripheral surface of the head main body 223. The cover 225 has, for example, a shape that slopes outward from a horizontally extending portion. In other words, the cover 225 has a trapezoidal shape. The lower end of the cover 225 is located higher than the lower surface of the polishing tool 96. This is to prevent the cover 225 from interfering with the substrate W even if the polishing tool 96 wears. The cover 225 includes a first cover 225a and a second cover 225b. The first cover 225a and the second cover 225b are formed to be line-symmetrical with respect to a straight line passing through the vertical axis AX5 in a plan view.

[0125] First cover 225a covers the side of opening 231. Second cover 225b covers the side of opening 233. The lower part of first cover 225a forms ejection port 235. The lower part of second cover 225b forms suction port 237. Ejection port 235 is provided along half the circumference of the outer circumferential surface of grinder 96. Suction port 237 is provided along half the circumference of the outer circumferential surface of grinder 96. Suction port 237 is formed so as to be symmetrical to ejection port 235 with respect to a line passing through vertical axis AX5 in a plan view.

[0126] In the polishing head 201, the first flow path 227 is connected to the other end of the gas supply pipe 203. In the polishing head 201, the second flow path 229 is connected to the other end of the suction pipe 205. In other words, the injection port 235 is connected to the gas supply source 213. The suction port 237 is connected to the suction source 219.

[0127] The polishing unit 22 configured as above polishes the substrate W, for example, as follows: The operation of the arm 101 and the like is as described above.

[0128] The main control unit 134 performs operations related to the supply and suction of gas. Specifically, the main control unit 134 sets the flow rate adjustment valve 215 to a predetermined supply flow rate in advance. This predetermined supply flow rate is preferably set within a range that does not exceed the flow rate suctioned from the suction pipe 205. The main control unit 134 opens the on-off valves 217, 221 in synchronization with the start of the polishing process or slightly earlier. As a result, nitrogen gas is supplied to the gas supply pipe 203 at the predetermined supply flow rate, and gas is suctioned from the suction pipe 205.

[0129] The polishing tool moving mechanism 97 described above corresponds to the "head driving mechanism" in the present invention. The polishing unit 22 described above corresponds to the "polishing device" in the present invention. The flow rate adjustment valve 215 and the on-off valve 217 described above correspond to the "control valve" in the present invention. The main control unit 134 described above corresponds to the "control unit" in the present invention.

[0130] According to this embodiment, dust generated on the back surface of the substrate W during polishing by the polishing tool 96 rotating about the vertical axis AX5 is pushed out to the outer periphery of the polishing tool 96 by centrifugal force. Nitrogen gas is sprayed there from the spray port 235. This causes dust adhering to the back surface of the substrate W to detach from the back surface of the substrate W. The dust is then sucked by the suction port 237. Therefore, dust is less likely to remain on the back surface of the substrate W, and the dust removal rate during polishing can be increased.

[0131] Furthermore, in this embodiment, the outer peripheral surface of the grinding tool 96 is divided into line-symmetrical sections in a plan view, each of which serves as an injection port 235 and a suction port 237. This allows a good balance to be maintained between the supply of nitrogen gas and suction on the outer peripheral surface of the grinding tool 96. This allows for good dust removal.

[0132] Furthermore, according to this embodiment, the flow rate of nitrogen gas from the injection port 235 is set so as not to exceed the flow rate due to suction. Therefore, dust caused by the injection of nitrogen gas from the injection port 235 is not sucked through the suction port 237, and it is possible to prevent the dust from scattering around.

[0133] It is preferable that the main control unit 134 operates the flow rate adjustment valve 215 to vary the flow rate of the nitrogen gas over time. In this case, the flow rate also includes a flow rate of 0, which means that no nitrogen gas is supplied. This causes the flow rate of the nitrogen gas injected from the injection port 235 to fluctuate. In other words, the supply of nitrogen gas becomes discontinuous or intermittent rather than constant. Furthermore, the main control unit 134 may operate the opening and closing of the on-off valve 217 while keeping the flow rate constant without operating the flow rate adjustment valve 215. This causes the injection of nitrogen gas from the injection port 235 to be discontinuous or intermittent.

[0134] If nitrogen gas is sprayed continuously, the dust may be pressed against the back surface of the substrate W, making it difficult to remove by suction. Therefore, the main control unit 134 operates the flow rate adjustment valve 215 and the on-off valve 217 to discontinuously spray nitrogen gas from the polishing head 201. If nitrogen gas is sprayed discontinuously and intermittently, the pressing force of the nitrogen gas is temporarily weakened, making it easier to remove the dust. [Example]

[0135] Second Embodiment A second embodiment of the present invention will be described below with reference to the drawings. The configuration except for the polishing head 201A is the same as that of the above-described embodiment.

[0136] Please refer to Figures 15 and 16. Figure 15 is a vertical cross-sectional view of the polishing head according to Example 2. Figure 16 is a bottom view of the polishing head according to Example 2.

[0137] The polishing head 201A includes a polishing tool 96A, a head body 223A, and a cover 225A. The polishing tool 96A is attached to the underside of the head body 223A. The head body 223A has a first flow path 241 and a second flow path 243 formed therein. The first flow path 241 and the second flow path 243 are not connected to each other. The first flow path 241 has an opening 245 formed on the underside of the head body 223A. The first flow path 241 is substantially aligned with the vertical axis AX5. The second flow path 243 connects the upper surface and outer peripheral surface of the head body 223A. The second flow path 243 has openings 247 formed at four locations on the outer peripheral surface of the head body 223A, for example. The second flow path 243 also communicates with the upper surface of the head body 223A at four locations, for example. In the second flow channel 243, it is preferable that the positional relationship of the openings 247 is equiangular in plan view, which allows for uniform suction.

[0138] The cover 225A is attached to the head body 223A. The cover 225A is attached to the outer peripheral surface of the head body 223A. The cover 225A has a shape that hangs downward from a horizontally directed portion, for example. The lower end of the cover 225A is located higher than the lower surface of the grinding tool 96. The lower part of the cover 225A forms a suction port 248.

[0139] The grinding tool 96A has a through hole 249 formed in the center. The grinding tool 96A has an annular shape in a plan view. In a plan view, the through hole 249 substantially overlaps with the vertical axis AX5. In a plan view, the through hole 249 overlaps with the first flow path 241. The through hole 249 communicates with the first flow path 241. Of the through hole 249, the opening that communicates with the underside of the grinding tool 96A is an injection port 251.

[0140] In the polishing head 201A, the first flow path 241 is connected to the other end of the gas supply pipe 203. In the polishing head 201A, the second flow path 243 is connected to the other end of the suction pipe 205. In other words, the injection port 251 is connected to the gas supply source 213. The suction port 248 is connected to the suction source 219.

[0141] According to this embodiment, nitrogen gas ejected from the center of the polishing tool 96A is directed toward the outer periphery of the polishing tool 96A on the back surface of the substrate W. Therefore, nitrogen gas containing dust can be efficiently sucked by the suction port 248. [Example]

[0142] Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. The configuration except for the polishing head 201B is the same as that of the above-described embodiments.

[0143] Please refer to Figures 17 and 18. Figure 17 is a vertical cross-sectional view of the polishing head according to Example 3. Figure 18 is a bottom view of the polishing head according to Example 3.

[0144] The polishing head 201B includes a polishing tool 96B, a head body 223B, and a cover 225A. The polishing tool 96B is attached to the underside of the head body 223B. The head body 223B is formed with a first flow path 241 and a second flow path 243. The first flow path 241 and the second flow path 243 are the same as those in the second embodiment. The head body 223B is formed with an edge portion 253. The edge portion 253 is formed by protruding downward from the edge portion of the underside of the head body 223B. The polishing part 96B is attached to this edge portion 253.

[0145] The polishing tool 96B is made of a porous material. A large number of small holes are formed in the polishing tool 96B. The large number of holes are connected to each other in communication with each other. Nitrogen gas supplied from the first flow path 241 passes through the large number of small holes in the polishing tool 96B and is sprayed from the bottom surface of the polishing tool 96B onto the back surface of the substrate W. In other words, the bottom surface of the polishing tool 96B forms an injection port 255.

[0146] The cover 225A has the same configuration as that of the second embodiment described above, and the lower part thereof forms the suction port 248.

[0147] According to this embodiment, nitrogen gas is supplied to the polishing tool 96B made of a porous member, and the nitrogen gas is sprayed onto the dust from the nozzles 255 that cover almost the entire bottom surface of the polishing tool 96B. Therefore, the dust can be efficiently pushed out to the periphery.

[0148] The present invention is not limited to the above-described embodiment, but can be modified as follows.

[0149] (1) In the above-described embodiments, suction is performed through the suction ports 237, 248, which have wide openings formed in the covers 225, 225A. However, the present invention is not limited to this configuration. For example, a piping structure may be employed in which one end of a pipe is connected to the opening 233, 247 of the head body 223 (223A, 223B) and the other end of the pipe faces the polishing surface.

[0150] (2) In each of the above-described embodiments, nitrogen gas is injected from the injection port. However, the present invention is not limited to nitrogen gas. For example, argon gas may be used as the gas.

[0151] (3) In each of the above-described embodiments, the gas supply pipe 203 and the suction pipe 205 are arranged in parallel. However, the present invention is not limited to this configuration. For example, a configuration may be adopted in which a double pipe is inserted into the shaft 100 and used for gas supply and suction.

[0152] (4) In the above-described embodiments, the main control unit 134 operates the flow rate control valve 215 to vary the flow rate of the nitrogen gas over time, but such an operation is not essential to the present invention. In other words, the flow rate of the nitrogen gas may be maintained constant throughout the polishing process.

[0153] (5) In each of the above-described embodiments, the polishing heads 201, 201A, and 201B are configured to be detachably attached to the mounting member 98. However, the polishing heads 201, 201A, and 201B may be semi-fixed to the mounting member 98, and only the polishing tools 96, 96A, and 96B may be detachable and easily replaceable.

[0154] (6) In the above-described embodiments, the holding and rotating unit 35 holds the substrate W with its back surface facing upward in a horizontal position. The spin base 41 of the holding and rotating unit 35 is disposed below the substrate W. In this regard, the holding and rotating unit 35 may be disposed upside down. That is, the spin base 41 of the holding and rotating unit 35 is disposed above the substrate W. The holding and rotating unit 35 holds the substrate W with its back surface facing downward in a horizontal position. In this case, the polishing tool 96 is brought into contact with the substrate W with its back surface facing downward from below the substrate W. [Industrial Applicability]

[0155] As described above, the present invention is suitable for a polishing head for polishing the back surface of a substrate, a polishing apparatus including the same, and a substrate processing apparatus. [Explanation of symbols]

[0156] 1... Substrate processing equipment W: Substrate 22 ... Polishing unit 35 ... Rotating holding part 37,37A … Polishing mechanism 96,96A,96B … Polishing tool 100... shaft 201, 201A, 201B ... Polishing head 203 Gas supply piping 205 … Suction piping 207...Rotary joint 209 ... Fixed body 211 ... Rotating body 213 ... Gas supply source 215 ... Flow control valve 217 ... On-off valve 219 … Suction source 221 ... On-off valve 223, 223A, 223B ... Head body 225,225A … Cover 227,241 ... First channel 229,243 ... Second channel 235,251.255 … jet nozzle 237,248 … Attraction

Claims

1. In a polishing head for polishing a substrate, a polishing tool having a resin body in which abrasive grains are dispersed; an injection port for injecting gas onto dust generated by grinding with the grinding tool; a suction port for sucking dust generated by grinding with the grinding tool, The injection port is provided along the outer circumferential surface of the grinding tool, The polishing head is characterized in that the suction port is provided along the outer peripheral surface of the polishing tool and is provided line-symmetrically with the injection port in a plan view.

2. A polishing head for polishing a substrate, comprising: a polishing tool having a resin body in which abrasive grains are dispersed; an injection port for injecting gas onto dust generated by grinding with the grinding tool; a suction port for sucking dust generated by grinding with the grinding tool, The grinding tool is provided in an annular shape in a plan view, The injection port is provided at the center of the grinding tool, The polishing head is characterized in that the suction port is provided over the entire outer periphery of the polishing tool.

3. A polishing head for polishing a substrate, comprising: a polishing tool having a resin body in which abrasive grains are dispersed; an injection port for injecting gas onto dust generated by grinding with the grinding tool; a suction port for sucking dust generated by grinding with the grinding tool, The polishing tool is made of a porous member having interconnected pores, The injection port is provided on the lower surface of the grinding tool, The polishing head is characterized in that the suction port is provided around the entire outer periphery of the polishing tool.

4. 4. The polishing head according to claim 1, The polishing head is characterized in that the injection port injects gas discontinuously.

5. In a polishing apparatus for polishing a substrate, A polishing head according to any one of claims 1 to 4; a head driving mechanism that drives the polishing head to rotate around a vertical axis; a holding and rotating unit that rotates the substrate while holding the substrate in a horizontal position; a gas supply pipe for supplying gas to the nozzle of the polishing head; a suction pipe for suctioning from a suction port of the polishing head; A polishing apparatus comprising:

6. 6. The polishing apparatus according to claim 5, a control valve that controls the flow of gas in the gas supply pipe; a control unit that operates the control valve; Furthermore, The polishing apparatus is characterized in that the control unit operates the control valve so that gas is intermittently sprayed from the polishing head.

7. 7. The polishing apparatus according to claim 6, The polishing apparatus is characterized in that the control unit operates the control valve so that the flow rate of the gas injected from the injection port does not exceed the flow rate of the gas sucked from the suction pipe.

8. A substrate processing apparatus comprising the polishing apparatus according to any one of claims 5 to 7.

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