Polishing method and substrate processing apparatus

Abstract

To provide a polishing method and a substrate treatment device which can satisfactorily perform polishing treatment.SOLUTION: A polishing method includes a rotation step of rotating a substrate W in a horizontal state, an etching step of supplying an etching liquid onto the rear face of the substrate W, and thereby removing a film formed on the rear face of the substrate W, and a polishing step of removing the film on the rear face of the substrate W, and then bringing a polishing tool 96 having a resin body where abrasive grains are dispersed into contact with the rear face of the rotated substrate W, and polishing the rear face of the substrate W by a chemical machinery polishing method.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a polishing method and a substrate processing apparatus for polishing the back surface of a substrate. 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 display devices and organic electroluminescence (EL) display devices. The back surface of a substrate refers to the side on which no electronic circuits are formed, as opposed to the front surface of the substrate, which is the side on which electronic circuits are formed (device side). [Background technology]

[0002] A polishing apparatus for polishing the backside of a substrate includes a polishing head and a holding / rotating unit. The polishing apparatus supplies a polishing liquid and polishes the substrate by bringing the polishing head into contact with the backside of the substrate (see, for example, Patent Document 1). The holding / rotating unit rotates the substrate while holding it in a horizontal position.

[0003] Another type of polishing apparatus is one that performs dry chemical mechanical grinding (CMG) on substrates (see, for example, Patent Document 2). This polishing apparatus is equipped with a synthetic grinding stone and a holding and rotating unit. The synthetic grinding stone is formed by fixing an abrasive (abrasive grains) with a resin binder. This polishing apparatus polishes the substrate by bringing the synthetic grinding stone into contact with the substrate. There is also a substrate processing apparatus equipped with a polishing tool for removing contaminants and contact marks on the back surface of the substrate (see, for example, Patent Document 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6162417 [Patent Document 2] Patent No. 6779540 [Patent Document 3] Patent No. 6740065 Summary of the Invention [Problem to be solved by the invention]

[0005] However, conventional devices with such a configuration have the following problem. In recent years, there has been a problem with defocus (so-called out-of-focus) in EUV (Extreme Ultraviolet) exposure devices due to the substrate flatness of the back surface of a substrate (e.g., a wafer). One cause of poor flatness is thought to be scratches. Therefore, in order to remove scratches, the use of the synthetic grindstone disclosed in Patent Document 2 as a polishing tool has been considered. However, it has been found that polishing the back surface of a substrate with a polishing tool may not result in good polishing.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a polishing method and a substrate processing apparatus that are capable of performing polishing processing well. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention has the following configuration: That is, the polishing method according to the present invention comprises a rotating step of rotating a substrate in a horizontal position, an etching step of removing a film formed on the back surface of the substrate by supplying an etching solution to the back surface of the substrate, and a polishing step of, after removing the film on the back surface of the substrate, bringing a polishing tool having a resin body in which abrasive grains are dispersed into contact with the back surface of the rotating substrate to polish the back surface of the substrate by a chemical mechanical grinding method. The film is formed during the device manufacturing process. It is characterized by the following.

[0008] According to the polishing method of the present invention, a polishing tool is brought into contact with the rear surface of a rotating substrate, and the rear surface of the substrate is polished by chemical mechanical polishing. It has been found that if a film is formed on the rear surface of the substrate, the film prevents the polishing from being performed satisfactorily. Therefore, an etching process is performed before the polishing process to remove the film formed on the rear surface of the substrate. This allows the polishing process to be performed satisfactorily.

[0009] Preferably, the polishing method further comprises a heating step of heating the substrate during polishing. Heating the substrate can increase the polishing rate, thereby shortening the polishing time.

[0010] Preferably, the polishing method further comprises a control step of adjusting the polishing rate by controlling the heating temperature of the substrate in the heating step. The polishing rate can be increased or decreased by increasing or decreasing the heating temperature of the substrate.

[0011] In the above-described polishing method, the control step preferably further adjusts the polishing rate by controlling at least one of the contact pressure of the polishing tool against the substrate, the movement speed of the polishing tool, the rotation speed of the polishing tool, and the rotation speed of the substrate. For example, the contact pressure of the polishing tool against the substrate can be reduced by increasing the heating temperature of the substrate while maintaining the polishing rate. This reduces the load on the substrate due to the contact pressure. In other words, it is possible to prevent the substrate W from being pressed too hard.

[0012] Furthermore, in the above-described polishing method, it is preferable that the film includes a first film and a second film, the etching liquid includes a first chemical liquid and a second chemical liquid, and the etching process includes a first etching process of removing the first film by supplying the first chemical liquid, and a second etching process of removing the second film by supplying the second chemical liquid. In the polishing method described above, No. 1 An example of an etching process is: The first film The object of the present invention is to remove the silicon oxide film. No. 1 An example of an etching process is: The first film The purpose of the polishing method is to remove the silicon nitride film. No. 2 The etching process is The second filmThe polysilicon film is removed.

[0013] Preferably, the polishing method further comprises an inspection step of detecting scratches formed on the back surface of the substrate by an inspection unit before the etching step, and the etching step is performed when the scratches are detected by the inspection unit, thereby making it possible to remove the detected scratches, i.e., the selected scratches, in the polishing step after the etching step.

[0014] In the polishing method described above, it is preferable that the inspection step includes detecting scratches formed on the back surface of the substrate by the inspection unit and measuring the depth of the scratch when the scratch is detected, the etching step is performed when the scratch is detected by the inspection unit, and the polishing step includes polishing the back surface of the substrate until a thickness corresponding to the scratch depth measured by the inspection unit is removed. This allows the depth of the scratch to be recognized, making it possible to appropriately polish the amount of polishing in the thickness direction of the substrate.

[0015] Preferably, the polishing method further comprises an inspection step of detecting scratches formed on the back surface of the substrate by an inspection unit between the etching step and the polishing step, and the polishing step is performed when the scratches are detected by the inspection unit. In the polishing step, scratches detected after the etching step, i.e., selected scratches, can be removed by scraping them off.

[0016] Further, the substrate processing apparatus according to the present invention comprises: a polishing unit and a control unit, a holding and rotating part that rotates the substrate while holding the substrate in a horizontal position; a polishing tool having a resin body in which abrasive grains are dispersed; and an etching liquid supply nozzle that supplies an etching liquid to the back surface of the substrate held by the holding and rotating part. ,of Preparation, the control unit causes the holding and rotating unit in the polishing unit to hold the substrate carried into the polishing unit, and after the control unit causes the holding and rotating unit to hold the substrate, the control unit causes the holding and rotating unit to rotate the substrate held in a horizontal position; The control unit The holding and rotating part rotates the polishing unit. On the backside of the substrate From the etching solution supply nozzleBy supplying an etching solution, a film formed on the rear surface of the substrate is removed, and after the control unit has removed the film on the rear surface of the substrate, In the polishing unit, the holding and rotating part The polishing tool is brought into contact with the rear surface of the rotating substrate, and the rear surface of the substrate is polished by chemical mechanical grinding. The film is formed during the device manufacturing process. It is characterized by the following.

[0017] In the substrate processing apparatus according to the present invention, a polishing tool is brought into contact with the rear surface of a rotating substrate, and the rear surface of the substrate is polished by chemical mechanical polishing. It has been found that if a film is formed on the rear surface of the substrate, the film prevents the polishing from being performed satisfactorily. Therefore, an etching process is performed before the polishing process to remove the film formed on the rear surface of the substrate. This allows the polishing process to be performed satisfactorily.

[0018] Furthermore, in the above-described substrate processing apparatus, it is preferable that the film includes a first film and a second film, the etching liquid includes a first chemical liquid and a second chemical liquid, and when removing a film formed on the back surface of the substrate, the control unit causes the first film to be removed by supplying the first chemical liquid from the etching liquid supply nozzle, and also causes the second film to be removed by supplying the second chemical liquid from the etching liquid supply nozzle. Furthermore, it is preferable that the above-mentioned substrate processing apparatus further includes a heating means for heating the substrate, and that the control unit, after removing the film on the rear surface of the substrate, brings the polishing tool into contact with the rear surface of the substrate that is being heated and rotated, thereby polishing the rear surface of the substrate by a chemical mechanical grinding method. [Effects of the Invention]

[0019] According to the polishing method and substrate processing apparatus of the present invention, the polishing process can be performed satisfactorily. [Brief explanation of the drawings]

[0020] [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] 10 is a flowchart showing the operation of the substrate processing apparatus according to the second embodiment. [Figure 13] FIG. 1 is a diagram showing the relationship between the heating temperature of a substrate and the contact pressure (pressing pressure) of a polishing tool. [Figure 14] FIG. 10 is a side view showing the configuration of a polishing unit according to Example 4. [Figure 15] FIG. 10 is a side view showing the configuration of a liquid processing unit according to a fourth embodiment. [Figure 16] 1A and 1B are diagrams showing a heater for heating a grinding tool. [Figure 17] FIG. 10 is a diagram showing the relationship between the combination of heating means and the heating temperature of the substrate. Example 1

[0021] 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.

[0022] (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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] (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.

[0031] 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.

[0032] 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.

[0033] (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. The holding and rotating unit 35 corresponds to the holding and rotating unit of the present invention.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] A hot plate 45 is provided on the upper surface of the spin base 41. The hot plate 45 includes 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 the gas discharge port 47 described below, and 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 includes a detection element that detects infrared rays emitted by the substrate W. The hot plate 45 corresponds to the heating means of the present invention. In Example 1, the polishing unit 22 does not include heaters 147, 154 (see FIG. 3) described below.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] First chemical liquid nozzle 65 and second chemical liquid nozzle 67 correspond to the etching liquid supply nozzle of the present invention. Furthermore, the first chemical liquid and second chemical liquid described below correspond to the etching liquid of the present invention.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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).

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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).

[0059] (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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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. The main control unit 134 corresponds to the control unit of the present invention.

[0066] (2) Operation of the substrate processing apparatus 1 Next, the operation of the substrate processing apparatus 1 will be described with reference to FIG.

[0067] [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.

[0068] [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.

[0069] 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.

[0070] [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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] [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 rear surface of the substrate W, the rear 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 FL formed on the rear surface of the substrate W by supplying a first chemical liquid (etchant) to the rear surface of the substrate W.

[0078] 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).

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] [Step S05] Polishing the back surface of the substrate W After the wet 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.

[0087] 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).

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] [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.

[0096] 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.

[0097] 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 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 can be performed without rotating the substrate W at high speed. 75 The gas may be supplied from the

[0098] 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.

[0099] 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.

[0100] 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.

[0101] [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.

[0102] [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.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] According to the substrate processing apparatus 1, the polishing tool 96 is brought into contact with the rear surface of the rotating substrate W, and the rear surface of the substrate W is polished by chemical mechanical polishing (CMG). Here, it has been found that if a film FL is formed on the rear surface of the substrate W, the film FL prevents the substrate W from being polished properly. Therefore, an etching process is performed before the polishing process to remove the film FL formed on the rear surface of the substrate W. This allows the polishing process to be performed properly. Example 2

[0107] Next, a second embodiment of the present invention will be described with reference to the drawings. Note that descriptions that overlap with those of the first embodiment will be omitted. Fig. 12 is a flowchart showing the operation of the substrate processing apparatus according to the second embodiment.

[0108] In Example 1, scratches were not observed after polishing the rear surface of the substrate W (step S05). In contrast, in Example 2, scratches were observed after polishing (step S51 in FIG. 12).

[0109] 12 are performed in substantially the same manner as steps S01 to S08 shown in Fig. 7. After the cleaning process of the substrate W (step S06), the substrate transport robot CR takes out the substrate W from the polishing unit 22 and transports the substrate W to one of the stages 121 of the two inspection units 20.

[0110] [Step S51] Observing scratches after polishing The inspection unit 20 particularly re-detects scratches formed on the back surface of the substrate W. That is, similar to the operation of step S03, the inspection unit 20 acquires an observation image using the camera 124 and the illumination 125. The inspection control unit 130 performs image processing on the acquired observation image to extract scratches on the polishing target. If scratches on the polishing target cannot be extracted, the main control unit 134 determines that re-polishing is not necessary, and proceeds to step S07.

[0111] On the other hand, if a scratch is detected on the object to be polished, the main control unit 134 determines that re-polishing is necessary. Then, the inspection unit 20 measures the depth of the scratch on the object to be polished. That is, the laser microscope 127 acquires a three-dimensional image including the scratch on the object to be polished. The inspection control unit 130 performs image processing on the acquired three-dimensional image and measures the depth of the scratch on the object to be polished (value DP3 in FIG. 8(b)).

[0112] Thereafter, the substrate transport robot CR transports the substrate W from the stage 121 of the inspection unit 20 to the holding and rotating part 35 of the polishing unit 22. After transport, the substrate W is held by the holding and rotating part 35, and gas is discharged from the gas discharge port 47. Thereafter, the substrate thickness measuring device 39 is moved above the substrate W and measures the thickness of the substrate W (value TK3 in FIG. 8(b)). The process returns to step S05.

[0113] In step S05, when the inspection unit 20 detects a scratch on the polishing target, the polishing unit 22 polishes the back surface of the substrate W again. Polishing is performed until a thickness (value DP3) corresponding to the depth of the scratch is removed. In other words, polishing is performed until the thickness of the substrate W reaches value TK2 (=TK3-DP3) shown in FIG. 8(b).

[0114] According to this embodiment, polishing is carried out until scratches on the polishing target that require polishing are eliminated, so that it is possible to prevent the edges of scratches from creating new scratches on the stage of an exposure machine, for example.

[0115] In this embodiment, if scratches are present on the polishing target, the wet etching step (step S04) is not performed. However, wet etching may be performed if necessary. Example 3

[0116] Next, a third embodiment of the present invention will be described with reference to the drawings. Note that the description overlapping with the first and second embodiments will be omitted.

[0117] FIG. 13 is a diagram showing the relationship between the heating temperature of the substrate W and the contact pressure (pressing pressure) of the polishing tool 96. FIG. 13 is a diagram when the polishing rate is constant. In FIG. 13, assume that a predetermined polishing rate RA is obtained when the temperature of the substrate W is room temperature (e.g., 25°C) and a predetermined contact pressure P1. Heating the substrate W increases the polishing rate. Therefore, if the temperature is increased above room temperature (e.g., to temperature TM2) while maintaining the polishing rate RA, a contact pressure P2 lower than the contact pressure P1 can be achieved. In other words, when the polishing rate RA is constant, the contact pressure can be reduced by increasing the temperature of the substrate W.

[0118] According to this embodiment, the polishing unit 22 can adjust the polishing rate by controlling the contact pressure of the polishing tool 96 on the substrate W in addition to the heating temperature of the substrate W. For example, by increasing the heating temperature of the substrate W while maintaining the polishing rate, the contact pressure of the polishing tool 96 on the substrate W can be reduced. This makes it possible to reduce the load on the substrate W due to the contact pressure. In other words, it is possible to prevent the substrate W from being pressed too hard.

[0119] The adjustment of the polishing rate is not limited to the relationship between the heating temperature of the substrate W and the contact pressure of the polishing tool 96. That is, the adjustment of the polishing rate may be performed based on the relationship between the heating temperature of the substrate W and the movement speed of the polishing tool 96. The adjustment of the polishing rate may also be performed based on the relationship between the heating temperature of the substrate W and the movement speed (oscillation speed) of the polishing tool 96 about the vertical axis AX6. The adjustment of the polishing rate may also be performed based on the relationship between the heating temperature of the substrate W and the rotation speed of the polishing tool 96 about the vertical axis AX5. The adjustment of the polishing rate may also be performed based on the relationship between the heating temperature of the substrate W and the rotation speed of the substrate W.

[0120] That is, the polishing unit 22 may adjust the polishing rate by controlling at least one of the contact pressure of the polishing tool 96 against the substrate W, the movement speed of the polishing tool 96, the rotation speed of the polishing tool 96, and the rotation speed of the substrate W, in addition to the heating temperature of the substrate W. Example 4

[0121] Next, a fourth embodiment of the present invention will be described with reference to the drawings. Note that the description overlapping with the first to third embodiments will be omitted.

[0122] 1, in Example 1, the processing unit U1 is the inspection unit 20, and each of the processing units U2 to U4 is the polishing unit 22. In Example 4, each of the processing units U2 and U3 may be the polishing unit 141, and the processing unit U4 may be the liquid processing unit 143. It should be noted that the processing unit U1 is the inspection unit 20.

[0123] That is, the substrate processing apparatus 1 of Example 4 includes two layers of inspection units 20, two layers of polishing units 141, and two layers of liquid processing units 143. In other words, the substrate processing apparatus 1 includes eight processing units U1 to U4. Fig. 14 is a diagram showing the polishing unit 141 according to Example 4. Fig. 15 is a diagram showing the liquid processing unit 143 according to Example 4.

[0124] 3 is divided into two. The liquid processing unit 143 includes a second holding / rotating unit 145 configured similarly to the holding / rotating unit 35. The polishing unit 141 may include a rinse liquid nozzle 73, a rinse liquid supply source 89, and a rinse liquid pipe 90. The polishing units 22 and 141 correspond to the polishing units of the present invention.

[0125] The operation of the substrate processing apparatus 1 is performed according to the flowchart shown in Fig. 7 or 12. However, for example, the substrate W is transported between the polishing unit 141 and the liquid processing unit 143. For example, during steps S03 to S06 in Fig. 7, the substrate W is transported by the substrate transport robot CR to the inspection unit 20, the liquid processing unit 143 (wet etching step), the polishing unit 141, and the liquid processing unit 143 (substrate W cleaning step) in this order.

[0126] This embodiment has the same effects as those of embodiment 1. Furthermore, since the configuration of polishing unit 22 in Fig. 2 is divided into two, each of polishing unit 141 and liquid processing unit 143 can be configured compactly.

[0127] The polishing unit 141 may be provided with a configuration related to the wet etching process (step S04) of the liquid processing unit 143. The polishing unit 141 may be provided with a configuration related to the cleaning process (step S06) of the substrate W of the liquid processing unit 143. In the fourth embodiment, the polishing unit 141 does not include heaters 147 and 154 (see FIG. 14), which will be described later.

[0128] The present invention is not limited to the above-described embodiment, but can be modified as follows.

[0129] (1) In each of the above-described embodiments, the polishing unit 22 includes a hot plate 45 as a heating means. The polishing unit 22 may be configured to discharge heated gas from the gas discharge port 47 instead of the hot plate 45. The substrate can be heated by the heated gas from the gas discharge port 47. In this case, for example, the polishing unit 22 may include a heater 147 (see FIGS. 3 and 14) that heats the gas passing through the gas pipe 61 from outside the gas pipe 61. In this case, the polishing unit 22 does not need to include the hot plate 45. The substrate W may be heated by both the hot plate 45 and the heated gas discharged from the gas discharge port 47. The gas discharge port 47 corresponds to the heating means of the present invention.

[0130] (2) In the above-described embodiments and modified example (1), the polishing unit 22 includes a hot plate 45 as a heating means. However, as shown in FIGS. 16(a) and 16(b), the polishing unit 22 may include a heater 149 (152) for heating the polishing tool 96 instead of the hot plate 45. Alternatively, the polishing unit 22 may include both the hot plate 45 and the heater 149 (152). In FIG. 16(a), the mounting member 98 is configured like a container with a recessed bottom. A ring-shaped heater 149 is provided in a hollow cylindrical portion 150 of the mounting member 98 that surrounds the polishing tool 96 (vertical axis AX5). The heater 149 heats the polishing tool 96. Heating the polishing tool 96 can heat the substrate W via the polishing tool 96. Furthermore, the interface between the polishing tool 96 and the rear surface of the substrate W can be effectively heated.

[0131] 16(b), the heater 152 may be built into the mounting member 98 and disposed between the shaft 100 and the grinding tool 96. Each heater 149, 152 may be heated by an electric heater such as a nichrome wire. Each heater 149, 152 may be provided with a pipe and heated by passing a heated gas or heated liquid through the pipe. Each heater 149, 152 corresponds to the heating means of the present invention.

[0132] (3) In the above-described embodiments and modifications, the rear surface of the substrate W is polished by dry chemical mechanical grinding using the polishing tool 96. Alternatively, the rear surface of the substrate W may be polished by chemical mechanical grinding using the polishing tool 96 while supplying a liquid to the rear surface of the substrate W. For example, heated deionized water (e.g., DIW) may be supplied from the rinse liquid nozzle 73 (FIGS. 3 and 14) onto the rear surface of the substrate W and near the polishing tool 96. The heated deionized water can heat the substrate W. Furthermore, the heated deionized water can wash away polishing debris from the rear surface of the substrate W. For example, the polishing unit 22 (141) may include a heater 154 that heats the deionized water passing through the rinse liquid pipe 90 from outside the rinse liquid pipe 90. Alternatively, the substrate W may be heated by heated deionized water from the rinse liquid nozzle 73 instead of by the hot plate 45. In this case, the polishing unit 22 does not need to include the hot plate 45. The rinse liquid nozzle 73 corresponds to the heating means of the present invention.

[0133] In addition, the substrate W may be heated by at least one of the hot plate 45, the gas outlet 47 that discharges heated gas, the heater 149 (or heater 152) that heats the polishing tool 96, and the rinse liquid nozzle 73 that supplies heated pure water to the back surface of the substrate W.

[0134] The polishing unit 22 may also be equipped with these heating means and may combine these heating means to control the heating temperature of the substrate W. For example, suppose that heating is performed using only the hot plate 45 (symbol H1 in FIG. 17). If further heating is desired, the substrate W may be heated not only by the hot plate 45 but also by a gas outlet 47 that discharges heated gas (symbol H1 + symbol H2 in FIG. 17). If further heating is desired, the substrate W may be heated not only by the hot plate 45 and the gas outlet 47 but also by a heater 149 (or heater 152) that heats the polishing tool 96 (symbol H1 + symbol H2 + symbol H3 in FIG. 17). If it is desired to suppress heating from this state, the substrate W may be heated only by the hot plate 45 (symbol H1).

[0135] (4) In each of the above-described embodiments and modifications, the substrate thickness measuring device 39 measured the thickness of the substrate W before the wet etching step (step S04). However, the substrate thickness measuring device 39 may measure the thickness of the substrate W between step S04 and the backside polishing step (step S05) of the substrate W. In this case, the scratch observation step (step S03) may be moved between steps S04 and S05.

[0136] (5) In the above-described embodiments and modifications, the polishing unit 22 and the main control unit 134 are provided in the substrate processing apparatus 1 together with the indexer block 3, etc. However, the polishing unit 22 and the main control unit 134 may be provided in a polishing apparatus.

[0137] (6) In each of the above-described embodiments and modifications, the contact pressure of the polishing tool 96 on the substrate W may be detected by, for example, a load cell. The movement speed of the polishing tool 96 may be detected by a rotary encoder that detects the angle of the polishing tool 96 about the vertical axis AX6. The rotation speed of the polishing tool 96 may be detected by a rotary encoder that detects the angle of the polishing tool 96 about the vertical axis AX5. The rotation speed of the substrate W may be detected by a rotary encoder that detects the angle of the substrate W about the rotation axis AX3. The main control unit 134 may control each component based on these detection results.

[0138] (7) In each of the above-described embodiments and modifications, 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.

[0139] (8) In the above-described embodiments and modifications, steps S21 to S26 are performed as the wet etching process (FIG. 9). Of the six steps S21 to S26, only steps S21 to S23 may be performed. Also, of the six steps S21 to S26, only steps S24 to S26 may be performed.

[0140] (9) In the above-described embodiments and modifications, steps S31 to S36 are performed as a cleaning process for the substrate W (FIG. 11). Of the six steps S31 to S36, only steps S31 to S33 may be performed. Also, of the six steps S31 to S36, only steps S34 to S36 may be performed. [Explanation of symbols]

[0141] 1... Substrate processing equipment 20 … Inspection unit 22,141 ... Polishing unit 35 ... Rotating holding part 37 … Polishing mechanism 41...Spin Base 43 ... Retaining pin 45...hot plate 47... Gas outlet 65 ... First chemical nozzle 67 ... Second chemical nozzle 73 ... Rinse liquid nozzle 96 … Polishing tools 117 ... Arm rotation mechanism 127 ... Laser scanning confocal microscope 130 ... Inspection control section 134 ... Main control unit 145 ... Second holding rotating part 147,149,152,154 … heater

Claims

1. a rotating step of rotating the substrate in a horizontal position; an etching step of removing a film formed on the rear surface of the substrate by supplying an etching solution to the rear surface of the substrate; a polishing step in which, after removing the film on the rear surface of the substrate, a polishing tool having a resin body in which abrasive grains are dispersed is brought into contact with the rear surface of the rotating substrate, thereby polishing the rear surface of the substrate by a chemical mechanical grinding method; A polishing method characterized in that the film is formed during a device manufacturing process.

2. 2. The polishing method according to claim 1, A polishing method further comprising a heating step of heating the substrate while polishing is being performed.

3. 3. The polishing method according to claim 2, A polishing method further comprising a control step of adjusting a polishing rate by controlling a heating temperature of the substrate in the heating step.

4. 4. The polishing method according to claim 3, The polishing method is characterized in that the control step further adjusts the polishing rate by controlling at least one of the contact pressure of the polishing tool against the substrate, the moving speed of the polishing tool, the rotational speed of the polishing tool, and the rotational speed of the substrate.

5. In the polishing method according to any one of claims 1 to 4, the membrane includes a first membrane and a second membrane; the etching solution includes a first chemical solution and a second chemical solution, The etching step includes: a first etching step of removing the first film by supplying the first chemical solution; and a second etching step of removing the second film by supplying the second chemical liquid. A polishing method characterized by:

6. 6. The polishing method according to claim 5, The polishing method is characterized in that the first etching step removes the silicon oxide film that is the first film.

7. 7. The polishing method according to claim 5 or 6, a polishing method characterized in that the first etching step removes the silicon nitride film that is the first film;

8. 8. The polishing method according to claim 5, a polishing method characterized in that the second etching step removes the polysilicon film that is the second film;

9. 9. The polishing method according to claim 1, an inspection step of detecting scratches formed on the rear surface of the substrate by an inspection unit before the etching step; The polishing method, wherein the etching step is performed when the scratch is detected by the inspection unit.

10. 10. The polishing method according to claim 9, The inspection step includes detecting the scratches formed on the rear surface of the substrate by the inspection unit, and measuring the depth of the scratches when the scratches are detected; The etching step is performed when the scratch is detected by the inspection unit; A polishing method characterized in that the polishing step polishes the rear surface of the substrate until a thickness corresponding to the depth of the scratch measured by the inspection unit is removed.

11. 9. The polishing method according to claim 1, an inspection step of detecting scratches formed on the rear surface of the substrate by an inspection unit between the etching step and the polishing step; The polishing method, wherein the polishing step is performed when the scratch is detected by the inspection unit.

12. A polishing unit; a control unit, The polishing unit includes: a holding and rotating unit that rotates the substrate while holding the substrate in a horizontal position; a polishing tool having a resin body in which abrasive grains are dispersed; an etching liquid supply nozzle that supplies an etching liquid to the back surface of the substrate held by the holding rotation unit, the control unit causes the substrate carried into the polishing unit to be held by the holding rotation unit in the polishing unit; the control unit causes the holding and rotating unit to hold the substrate, and then rotates the substrate held by the holding and rotating unit in a horizontal position; the control unit controls the etching solution supply nozzle to supply an etching solution to a rear surface of the substrate rotated by the holding rotation unit in the polishing unit, thereby removing a film formed on the rear surface of the substrate; the control unit, after removing the film on the rear surface of the substrate, brings the polishing tool into contact with the rear surface of the substrate rotated by the holding rotation unit in the polishing unit, and polishes the rear surface of the substrate by a chemical mechanical grinding method; The substrate processing apparatus is characterized in that the film is formed in a device manufacturing process.

13. The substrate processing apparatus according to claim 12, the membrane includes a first membrane and a second membrane; the etching solution includes a first chemical solution and a second chemical solution, The control unit, when removing a film formed on the back surface of the substrate, causes the first film to be removed by supplying the first chemical liquid from the etching liquid supply nozzle, and causes the second film to be removed by supplying the second chemical liquid from the etching liquid supply nozzle.

14. 14. The substrate processing apparatus according to claim 12, Further comprising a heating means for heating the substrate, The control unit removes the film from the rear surface of the substrate, and then brings the polishing tool into contact with the rear surface of the substrate that is being heated and rotated, thereby polishing the rear surface of the substrate by a chemical mechanical grinding method.

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