Substrate processing apparatus and substrate processing method

Abstract

This substrate treatment device removes an object to be removed from a substrate using a treatment solution. The substrate treatment device comprises: a holding unit that holds the substrate; a solution supply unit that supplies treatment solution to the substrate that is held by the holding unit; an electrode that is disposed so as not to be in contact with the substrate that is held by the holding unit, and makes contact with the treatment solution that is supplied from the solution supply unit; an electric power source that applies a voltage to the electrode; and a control unit that controls the solution supply unit and the electric power source. The control unit generates OH radicals in the treatment solution that is supplied from the solution supply unit, by applying a voltage to the electrode with the electrode and the substrate in contact with the treatment solution, and provides the OH radicals to the object to be removed.

Description

Technical Field

[0001] The present disclosure relates to a substrate processing apparatus and a substrate processing method.

Background Art

[0002] Conventionally, in a substrate processing method for etching a resist film, a metal film, a metal nitride film, and polymer residues (hereinafter collectively referred to as removal targets) on the surface of a substrate, sulfuric acid and hydrogen peroxide water are supplied to the removal targets on the surface of the substrate. The sulfuric acid and hydrogen peroxide water supplied to the surface of the substrate can peel off the removal targets from the substrate by their oxidizing power.

[0003] Further, Patent Document 1 discloses a substrate processing apparatus that reduces the environmental load by irradiating UV light on droplets obtained by mixing oxygen gas and ozone water without using sulfuric acid, and supplying these droplets to a resist film to remove the resist film.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present disclosure provides a technique capable of efficiently removing removal targets on the surface of a substrate.

Means for Solving the Problems

[0006] According to one aspect of the present disclosure, a substrate processing apparatus for removing a target from a substrate using a processing liquid comprises: a holding unit for holding the substrate; a liquid supply unit for supplying the processing liquid to the substrate held in the holding unit; an electrode positioned at a distance from the substrate held in the holding unit and in contact with the processing liquid supplied from the liquid supply unit; a power supply for applying a voltage to the electrode; and a control unit for controlling the liquid supply unit and the power supply, wherein the control unit applies a voltage to the electrode while the electrode and the substrate are in contact with the processing liquid supplied from the liquid supply unit, thereby generating OH radicals in the processing liquid and applying the OH radicals to the target to be removed. The electrode includes a first electrode and a second electrode, the first electrode is in contact with the processing liquid that flows between the first electrode and the substrate, and the second electrode is located further from the substrate than the first electrode and is electrically connected to the first electrode through the processing liquid that is continuously supplied by the liquid supply unit. A substrate processing device is provided. [Effects of the Invention]

[0007] According to one embodiment, the target material to be removed from the surface of the substrate can be efficiently removed. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram showing the overall configuration of a substrate processing apparatus according to one embodiment. [Figure 2] Figure 2(A) is a schematic plan view showing the opposing portion of the first electrode according to one embodiment. Figure 2(B) is a schematic plan view showing the opposing portion according to the first modified example. [Figure 3] This is a magnified cross-sectional view showing the generation of OH radicals by electrolysis in a substrate processing device. [Figure 4] This is a flowchart of a substrate processing method according to one embodiment. [Figure 5] Figure 5(A) is a schematic plan view showing the opposing parts according to the second modified example. Figure 5(B) is a schematic plan view showing the opposing parts according to the third modified example. [Figure 6] This is a schematic diagram partially illustrating a substrate processing apparatus according to the fourth modified example. [Figure 7] Figure 7(A) is a schematic plan view showing the first electrode according to the fifth modified example. Figure 7(B) is a schematic plan view showing the first electrode according to the sixth modified example. [Figure 8] This is a schematic diagram partially illustrating a substrate processing apparatus according to the seventh modified example. [Figure 9] This is a schematic diagram partially illustrating a substrate processing apparatus according to the eighth modified example. [Figure 10] This is a schematic plan view partially showing a substrate processing apparatus according to the ninth modified example. [Figure 11] This is a schematic plan view partially showing a substrate processing apparatus according to the 10th modified example. [Modes for carrying out the invention]

[0009] The following describes embodiments for implementing this disclosure with reference to the drawings. In each drawing, the same reference numerals are used for identical components, and redundant explanations may be omitted.

[0010] In one embodiment, the substrate processing apparatus 1, as shown in Figure 1, performs an etching process to remove the target A on the surface of the substrate W by supplying a processing solution L to the target A. Furthermore, the substrate processing apparatus 1 shown in Figure 1 is configured as a single-wafer type apparatus that processes substrates W one at a time.

[0011] Examples of materials to be removed from the surface of the substrate W include a resist film, a metal film, a metal nitride film, or polymer (resin) residue remaining on the substrate W. The resist film contains a resin (polymer) and a photosensitive agent. The resist film may be one that has been cured by exposure to an ion beam. Examples of metal films include those containing at least one of tungsten (W), titanium nitride (TiN), cobalt (Co), nickel (Ni), ruthenium (Ru), molybdenum (Mo), and aluminum (Al). The metal film may be a single metal or an alloy. An example of a metal nitride film is titanium nitride (TiN). Polymer residue is a polymer foreign substance that remains unintentionally on the surface of the substrate W due to a substrate treatment other than that of this embodiment. Below, we will describe an example of removing a resist film from a substrate W that has a resist film as the material to be removed A.

[0012] The substrate processing apparatus 1 includes a processing chamber 10, a holding unit 20 that holds a substrate W inside the processing chamber 10, a liquid supply unit 30 that supplies a processing liquid L to the substrate W inside the processing chamber 10, a power supply unit 40 that supplies power to the processing liquid L, and a cup 50 that recovers the used processing liquid L. Further, the substrate processing apparatus 1 includes a control unit 90 that controls each component of the substrate processing apparatus 1.

[0013] The processing chamber 10 is formed in a box shape that houses the holding unit 20 and the cup 50 inside. The processing chamber 10 has a gate 11 and a gate valve 12 that opens and closes the gate 11. The substrate W is transported by a transfer device 2 and carried into the processing chamber 10 through the gate 11 in an open state of the gate valve 12. Thereafter, when the gate valve 12 hermetically closes the gate 11, the substrate W is subjected to an etching process inside the processing chamber 10. When the gate valve 12 opens after the substrate processing, the substrate W is delivered to the transfer device 2 that has entered the processing chamber 10 and carried out of the processing chamber 10 through the gate 11.

[0014] The holding unit 20 horizontally holds the substrate W inside the processing chamber 10 during substrate processing. The holding unit 20 has a disk-shaped base 21 and a chuck mechanism 22 that holds the surface of the substrate W (removal target A) facing upward in the vertical direction. The chuck mechanism 22 applies a mechanical chuck that grips the outer peripheral edge of the substrate W in FIG. 1, but is not limited thereto, and for example, a vacuum suction chuck, an electrostatic chuck, etc. may be used. Further, the holding unit 20 is provided with a plurality of lift pins (not shown) that lift the substrate W from the chuck mechanism 22 and receive and deliver the substrate W to and from the transfer device 2.

[0015] The holding unit 20 is supported by a substrate rotation unit 61, which is one of the rotation units 60 of the substrate processing apparatus 1. The rotation unit 60 relatively rotates at least one of the substrate W and the first electrode 41 of the power supply unit 40 with respect to the other. Note that the rotation unit 60 according to the present embodiment is configured to rotate both the substrate W and the first electrode 41.

[0016] The substrate rotating section 61 includes a holding shaft section 62 that fixes the base 21 of the holding section 20 at its upper end, and a rotating unit 63 that supports the lower end of the holding shaft section 62 and rotates the holding shaft section 62. The rotating unit 63 has a motor and a drive transmission mechanism (not shown) and is communicatively connected to the control section 90. The rotating unit 63 drives the motor under the control of the control section 90 to rotate the substrate W held by the holding section 20 via the holding shaft section 62 at a target rotational speed.

[0017] The liquid supply unit 30 discharges liquid onto the surface of the substrate W held by the holding unit 20. The liquid supply unit 30 includes, for example, a tubular nozzle 31 having a liquid flow path inside, and a nozzle moving unit 32 that moves the nozzle 31 inside the processing container 10. The liquid supply unit 30 also has an external supply unit 70 that supplies liquid to the nozzle 31 from outside the processing container 10.

[0018] The nozzle 31 is positioned above the substrate W held by the holding portion 20. The nozzle 31 has an L-shape when viewed from the side, extends horizontally from the side wall of the processing container 10 toward the vicinity of the center of the holding portion 20, and has a protruding end that bends downward near the center of the holding portion 20. At the lower end of the protruding end, there is an outlet 31a that communicates with the flow path of the nozzle 31 and discharges liquid onto the surface of the substrate W.

[0019] The nozzle moving unit 32 moves the nozzle 31 in the horizontal and vertical directions. The nozzle moving unit 32 has a motor and a drive transmission mechanism (not shown) and is communicatively connected to the control unit 90. The nozzle moving unit 32 operates under the control of the control unit 90 to position the nozzle 31 in a retracted position where the nozzle is moved away from the cup 50, and in a discharge position where the discharge port 31a is located approximately in the center of the substrate W.

[0020] The external supply unit 70 supplies liquid to the nozzle 31 from outside the processing container 10 during substrate processing. Examples of liquids used for substrate processing include a processing solution L (chemical solution) used for etching and a rinsing solution to replace the processing solution L after etching. Figure 1 illustrates a configuration in which one nozzle 31 discharges the processing solution L and the rinsing solution in sequence, but the substrate processing apparatus 1 may also be configured to discharge different types of processing solutions L using multiple nozzles 31. The external supply unit 70 may also be configured to discharge a drying solution (for example, an organic solvent such as isopropylene alcohol) that is more volatile than the rinsing solution after the rinsing solution has been discharged, thereby replacing the rinsing solution with the drying solution.

[0021] The processing solution L is preferably an aqueous solution containing an appropriate electrolyte depending on the type (anode, cathode) of the first electrode 41 of the power supply unit 40 facing the substrate W. For example, if the first electrode 41 is the anode, an aqueous solution containing at least one of HF, HCl, NH4OH, TMAH (tetramethylammonium hydroxide: Me4NOH), H2SO4, H3PO4, HNO3, etc. is used. In particular, if the target to be removed A is a resist film, an alkaline aqueous solution is more preferable to promote dissolution. If the first electrode 41 is the cathode, an aqueous solution containing H2O2 is used, for example, SC1 (NH4OH + H2O2), SC2 (HCl + H2O2), etc. On the other hand, the rinsing solution is, for example, DIW (deionized water).

[0022] The external supply unit 70 includes a processing liquid supply path 71 for supplying processing liquid L to the nozzle 31, a processing liquid source 72 located upstream of the processing liquid supply path 71, a rinse liquid supply path 73 for supplying rinse liquid to the nozzle 31, and a rinse liquid source 74 located upstream of the rinse liquid supply path 73. The processing liquid supply path 71 and the rinse liquid supply path 73 are composed of tubes having internal flow paths through which liquid can flow, and are equipped with valves 71v and 73v at intermediate positions to open and close the flow paths. Furthermore, the processing liquid supply path 71 and the rinse liquid supply path 73 are equipped with a pump for pressurizing the processing liquid L, a flow rate regulator for adjusting the flow rate of the processing liquid L, a temperature regulator for adjusting the temperature of the processing liquid L, etc. (neither shown). The rinse liquid supply path 73 also merges with the processing liquid supply path 71 at an intermediate position. As a result, the external supply unit 70 can selectively supply processing liquid L and rinse liquid to the nozzle 31 under the control of the control unit 90.

[0023] The power supply unit 40 has a pair of electrodes that apply a voltage to the processing liquid L discharged during etching, and generates OH radicals (hydroxyl radicals) in the processing liquid L by electrolysis of the processing liquid L by the pair of electrodes. The power supply unit 40 includes a pair of electrodes, a first electrode 41 and a second electrode 42, a power supply 43 that applies a voltage to the pair of electrodes, an electrode rotation unit 44 that rotates the first electrode 41, and an electrode moving unit 45 that moves the first electrode 41. That is, the electrode rotation unit 44 constitutes part of the rotation unit 60 that rotates the first electrode 41 relative to the substrate W. The electrode moving unit 45 moves the first electrode 41 to position it in a processing position facing the substrate W held by the holding unit 20 and an electrode retraction position retracted outside the cup 50.

[0024] The first electrode 41 is positioned adjacent to the substrate W held by the holding part 20, at a distance from it, and is an electrode that generates OH radicals in the processing liquid L it contacts. Depending on the connection configuration with the power supply 43, the first electrode 41 may be either an anode or a cathode. However, if an anode is used, a processing liquid L (electrolyte aqueous solution) and electrode material appropriate for the anode shall be applied, and if a cathode is used, a processing liquid L and electrode material appropriate for the cathode shall be applied.

[0025] The first electrode 41 comprises an opposing portion 411 positioned to face the holding portion 20, and an electrode shaft portion 412 that supports the center of the opposing portion 411. In plan view, the opposing portion 411 is formed in a circular shape with a diameter approximately the same as that of the substrate W, and has an electrode surface 411a that faces the entire surface of the substrate W. When positioned in the processing location, the opposing portion 411 is supported by the electrode shaft portion 412 such that its center coincides with the center of the substrate W and is parallel to the surface of the substrate W held by the holding portion 20. A processing space PS is formed between the electrode surface 411a and the surface of the substrate W, through which the processing liquid L can flow during the etching process.

[0026] The width of the processing space PS (the distance D between the electrode surface 411a of the opposing portion 411 and the surface of the substrate W: see Figure 3) is preferably set to a range of, for example, 0.5 mm to 5 mm. This allows the OH radicals of the generated processing liquid L to be smoothly applied to the resist film A, which is the target of removal. If the width of the processing space PS is less than 0.5 mm, the processing liquid L discharged from the nozzle 31 may have difficulty entering the processing space PS. Also, if the width of the processing space PS exceeds 5 mm, there is a higher possibility that the OH radicals generated at the first electrode 41 will disappear without reaching the substrate W, which may reduce processing efficiency.

[0027] As described above, it is preferable to select a material appropriate for the opposing portion 411 depending on the type of electrode (anode, cathode), etc. For example, if the first electrode 41 is the anode, it is preferable to use boron-doped diamond (hereinafter referred to as BDD). The boron-doping concentration of the BDD used as the first electrode 41 is preferably set to a mass in the range of 1000 ppm to 20000 ppm. By using this BDD, even when the voltage applied to the processing liquid L is increased, the first electrode 41 can increase the oxygen overpotential, making it difficult to generate oxygen from the processing liquid L. Therefore, the power supply unit 40 can apply a high voltage and efficiently generate reactive oxygen species such as OH radicals instead of oxygen.

[0028] On the other hand, when the first electrode 41 is the cathode, it is preferable to use a chemical-resistant precious metal, or carbon or BDD. Examples of chemical-resistant precious metals include gold (Au) and palladium (Pd). However, it is preferable not to use platinum (Pt), which is one of the precious metals, on the first electrode 41. This is because platinum acts as a catalyst and decomposes the aqueous solution H2O2. The first electrode 41 may also be constructed by forming the disc-shaped base portion from another conductive material, and only the electrode surface 411a may be coated with the above materials (gold, palladium, carbon, BDD).

[0029] As shown in Figure 2(A), the opposing portion 411 of the first electrode 41 is provided with a plurality of holes (four through holes 413) located a short distance radially outward from the center (electrode shaft portion 412). Each through hole 413 is located at the same distance from the electrode shaft portion 412 and is equally spaced from one another. Each through hole 413 allows the processing liquid L discharged from the nozzle 31 to pass from the upper surface side of the opposing portion 411 into the processing space PS on the electrode surface 411a side. The processing liquid L supplied to the processing space PS is distributed across the entire radial direction of the substrate W by centrifugal force. Of course, the number of through holes 413 is not particularly limited.

[0030] Alternatively, the first electrode 41 is not limited to a configuration having multiple through holes 413 near the center of the flat plate-shaped opposing portion 411, and various forms of opposing portions 411 may be used. For example, as shown in the first modified example in Figure 3B, the opposing portion 411A can be formed to have a mesh (network: holes) as a whole by weaving together multiple electrode wires 414. This makes it easier for the opposing portion 411A to guide the processing liquid L discharged from the nozzle 31 into the processing space PS below the opposing portion 411A.

[0031] The electrode shaft portion 412 is formed in a rod shape from a conductive material. The upper end of the electrode shaft portion 412 is connected to the electrode rotating portion 44 and the electrode moving portion 45 inside the processing container 10. The lower end of the electrode shaft portion 412 is fixed to the center of the opposing portion 411. The opposing portion 411 and the electrode shaft portion 412 may be made of different materials and connected by appropriate joining means, or they may be integrally molded from the same material.

[0032] The electrode rotating unit 44 is composed of a motor and a drive transmission mechanism (not shown) and is connected to the control unit 90. Under the control of the control unit 90, the electrode rotating unit 44 rotates the electrode shaft 412 and the opposing part 411 at a target rotational speed. The rotation direction of the first electrode 41 may be set to be, for example, opposite to the rotation direction of the substrate W by the substrate rotating unit 61. This causes the first electrode 41 and the substrate W to face the discharge port 31a of the nozzle 31 at different timings, allowing the processing liquid L discharged from the discharge port 31a to spread smoothly over the entire surface of the substrate W. The rotating unit 60 may change the relative position between the first electrode 41 and the substrate W by setting the rotation direction of the first electrode 41 and the rotation direction of the second electrode 42 to be the same and shifting their target rotational speeds.

[0033] The electrode moving unit 45 is composed of a motor and a drive transmission mechanism (not shown) and is connected to the control unit 90. The electrode rotating unit 44 moves the electrode shaft 412 and the opposing part 411 horizontally and vertically under the control of the control unit 90, and positions the first electrode 41 at the processing position and the electrode retraction position as described above. The power supply unit 40 may include a mechanism that integrates the electrode rotating unit 44 and the electrode moving unit 45.

[0034] The second electrode 42 is positioned midway along the nozzle 31 and within the flow path, allowing it to be in constant contact with the processing liquid L flowing through the nozzle 31. The material of the second electrode 42 is not particularly limited, as long as it has conductivity and chemical resistance.

[0035] The power supply 43 is connected to the first electrode 41 via wiring 46 and to the second electrode 42 via wiring 47. The wiring configuration of the power supply 43 can be arbitrarily set according to the polarity of the first electrode 41 facing the substrate W. In the following, we will describe the case where the first electrode 41 is the anode and the second electrode 42 is the cathode, as shown in Figure 1.

[0036] The power supply 43 is communicatively connected to the control unit 90 and applies a DC voltage to the first electrode 41 and the second electrode 42 under the control of the control unit 90. The output voltage applied by the power supply 43 is preferably in the range of 1.8V to 2.2V. Here, with general electrodes such as glassy carbon, oxygen is generated when the anode voltage is increased, but the first electrode 41 to which BDD is applied has a large oxygen overpotential and oxygen is not easily generated. For this reason, the power supply 43 can apply a high voltage and can generate reactive oxygen species such as OH radicals around the first electrode 41 effectively.

[0037] The first electrode 41 and the second electrode 42, configured as described above, conduct electricity through the processing solution L during the etching process. Specifically, as shown in Figure 3, the processing solution L (e.g., TMAH) present in the nozzle 31 and the processing space PS is in contact with the electrode surface 411a of the opposing portion 411 of the first electrode 41 and the second electrode 42. In this state, the power supply unit 40 applies a voltage of a predetermined output value (e.g., 2V) to the first electrode 41 and the second electrode 42. As a result, the following reactions [1] and [2] occur around the electrode surface 411a. [1] 2H2O = O2 + 4H + +4e - [2] H2O = ·OH + H + +e -

[0038] In other words, the reaction in [2] directly generates OH radicals (·OH). Furthermore, near the electrode surface 411a, the application of a high voltage causes the following reactions [3] and [4] to occur, which generate ozone (O3) and hydrogen peroxide (H2O2). Then, the ozone (O3) and hydrogen peroxide (H2O2) generated by these reactions further cause the following reaction [5], which indirectly generates OH radicals. [3] 2H2O = H2O2 + 2H + +2e - [4] 3H2O = O3 + 6H + +6e - [5] O3 + H2O2 = ·OH + HO2 + O2

[0039] The lifetime of the OH radicals generated by the above reaction is short, less than 200 μs. However, because the electrode surface 411a is positioned sufficiently close to the surface of the substrate W (the width of the processing space PS is 5 mm or less), the OH radicals can be easily guided to the resist film A, which is the target of removal. The OH radicals have strong oxidizing power and oxidize the resist film they come into contact with. As a result, it becomes possible to smoothly peel the resist film from the surface of the substrate W.

[0040] Returning to Figure 1, the cup 50, located inside the processing container 10, surrounds the outer edge of the substrate W held by the holding portion 20 and receives the processing liquid L that splashes from the outer edge of the substrate W. In this embodiment, the cup 50 is non-rotating, but it may be configured to rotate together with the holding shaft portion 62. The bottom wall of the cup 50 is provided with a drain pipe 51 for discharging the liquid accumulated inside the cup 50 and an exhaust pipe 52 for discharging the gas accumulated inside the cup 50.

[0041] Furthermore, the substrate processing apparatus 1 is equipped with a detection unit 80 located at a different location from the processing container 10 (outside the processing container 10) to detect OH radicals generated by applying a voltage to the processing liquid L. The detection unit 80 includes an extraction path 81 branching off from the processing liquid supply path 71, a reaction liquid source 82 that supplies a reaction liquid that reacts with OH radicals, a reaction liquid supply path 83 through which the reaction liquid from the reaction liquid source 82 flows, and a reactor 84 into which a mixture of the processing liquid L and the reaction liquid flows. The extraction path 81 and the reaction liquid supply path 83 merge in a confluence path 85 upstream of the reactor 84 to form a mixture. Additionally, a detection mechanism 86 is provided downstream of the reactor 84 to detect the amount of OH radicals generated in the mixture.

[0042] The extraction path 81 is composed of a tube having an internal channel through which the processing liquid L can flow, and is equipped with a valve 81v at an intermediate position to open and close the channel. Similarly, the reaction liquid supply path 83 is composed of a tube having an internal channel through which the reaction liquid can flow, with a reaction liquid source 82 connected to its upstream end, and is equipped with a valve 83v at an intermediate position to open and close the channel.

[0043] One possible reaction solution supplied by the reaction source 82 is terephthalic acid (TA), which acts as a scavenger for OH radicals and does not react with other radicals (O2 radicals, HO2 radicals, H2O2 radicals). Terephthalic acid is nonfluorescent before reacting with OH radicals, but becomes fluorescent when it reacts with OH radicals to form 2-hydroxyterephthalic acid (HTA). Therefore, the detection mechanism 86 can detect the amount of OH radicals by irradiating the mixture discharged from the reactor 84 with excitation light of a predetermined wavelength and receiving the fluorescence of HTA.

[0044] The reactor 84 into which the mixed liquid flows has a structure that allows for the temporary storage of the mixed liquid and the application of voltage to the mixed liquid. Specifically, the reactor 84 includes a cylindrical container 841, a first detection electrode 842 connected to a wiring 46 between the power supply 43 and the first electrode 41, and a second detection electrode 843 connected to a wiring 47 between the power supply 43 and the second electrode 42. The container 841 has a confluence path 85 connected to one axial end and a detection mechanism 86 connected to the other axial end.

[0045] The first detection electrode 842 and the second detection electrode 843 are exposed inside the container 841 and come into contact with the mixed liquid flowing into the container 841 from the confluence path 85. Preferably, the distance between the first detection electrode 842 and the second detection electrode 843 is set to be approximately equal to the distance between the first electrode 41 and the second electrode 42 of the processing container 10. This allows the detection unit 80 to make the conditions for electrolyzing the mixed liquid by applying voltage to the first detection electrode 842 and the second detection electrode 843 in the reactor 84 the same as the conditions for electrolyzing the processing liquid L by applying voltage to the first electrode 41 and the second electrode 42 in the processing container 10.

[0046] The detection mechanism 86 optically detects fluorescent substances generated in the reactor. The detection mechanism 86 includes a sample tube 861 connected to the reactor 84, an irradiation unit 862 that irradiates the detection unit 861a of the sample tube 861 with excitation light, and a light receiving unit 863 that receives the fluorescence generated in the detection unit 861a. The irradiation unit 862 is connected to the control unit 90 and, under the control of the control unit 90, emits excitation light having a wavelength of, for example, 310 nm onto the detection unit 861a. The light receiving unit 863 is connected to the control unit 90 and transmits an electrical signal to the control unit 90 corresponding to the amount of fluorescence received. Based on this electrical signal, the control unit 90 calculates the amount of OH radicals generated in the mixture.

[0047] The control unit 90 of the substrate processing apparatus 1 is a control computer having a processor 91, memory 92, input / output interfaces (not shown), and electronic circuits. The processor 91 is a combination of one or more of the following: CPU (Central Processing Unit), GPU (Graphics Processing Unit), ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array), and circuits consisting of multiple discrete semiconductors. The memory 92 includes non-volatile memory (e.g., compact discs, DVDs, hard disks, flash memory, etc.) and volatile memory, and forms the storage section of the control unit 90.

[0048] The control unit 90 controls the operation of the entire substrate processing apparatus 1 by having the processor 91 execute a program stored in the memory 92. In substrate processing, the control unit 90 sequentially performs predetermined processes by coordinating the holding unit 20, the liquid supply unit 30 (including the external supply unit 70), the power supply unit 40, the rotating unit 60, and the detection unit 80 with each other. The substrate processing apparatus 1 may be configured such that the control unit 90 directly controls multiple components, or it may be configured such that each of the multiple components has its own control board, and the control unit 90 sends commands to each control board to control its operation.

[0049] The substrate processing apparatus 1 according to this embodiment is basically configured as described above, and its operation (substrate processing method) will be explained below with reference to the flowchart in Figure 4.

[0050] In the substrate processing of the substrate processing apparatus 1, the control unit 90 first loads the substrate W into the processing container 10 (step S1) to remove the resist film (target A) from the substrate W. At this time, the control unit 90 opens the gate valve 12 and moves the substrate W above the holding unit 20 using the transport device 2, and transfers the substrate W to the raised lift pins. After the transport device 2 retracts, the control unit 90 lowers each lift pin and then operates the chuck mechanism 22 to hold the substrate W horizontally with the holding unit 20. The processing container 10 is then sealed by the gate valve 12.

[0051] Next, the control unit 90 operates the detection unit 80 installed outside the processing container 10 to adjust the voltage applied to the processing liquid L, thereby performing a voltage adjustment process (step S2). Note that the voltage adjustment process may be performed before the substrate W is brought into the processing container 10.

[0052] In the voltage adjustment process, the control unit 90 closes valves 71v and 73v and opens valves 81v and 83v. As a result, the processing liquid L (TMAH) flows from the processing liquid source 72 into the extraction path 81, and the reaction liquid (TA) flows from the reaction liquid source 82 into the reaction liquid supply path 83, and the processing liquid L and reaction liquid merge in the confluence path 85. The mixture of processing liquid L and reaction liquid then flows from the confluence path 85 into the reactor 84.

[0053] In this state, the control unit 90 starts electrolysis of the mixture in the reactor 84. The control unit 90 applies a predetermined voltage to the first detection electrode 842 and the second detection electrode 843 to generate OH radicals in the mixture in the reactor 84. These OH radicals react with the mixed reaction solution to form fluorescent 2-hydroxyterephthalic acid (HTA). The sample tube 861 of the detection mechanism 86 begins to receive a mixture containing HTA corresponding to the reaction state of the reactor 84. The detection mechanism 86 irradiates the detection area 861a of the sample tube 861 with excitation light from the irradiation unit 862, and when the light receiving unit 863 receives the fluorescence of HTA, it transmits an electrical signal corresponding to the amount of fluorescence to the control unit 90.

[0054] The control unit 90 calculates the amount of OH radicals based on this electrical signal and determines whether the calculated amount of OH radicals is within the target range. If it is outside the target range, it adjusts the voltage applied from the power supply 43 to the first detection electrode 842 and the second detection electrode 843. For example, if the calculated amount of OH radicals is less than the target range, the voltage is increased, and if the calculated amount of OH radicals is more than the target range, the voltage is decreased. This makes it possible for the substrate processing apparatus 1 to optimize in advance the voltage that the power supply 43 actually applies to the first electrode 41 and the second electrode 42 in the processing container 10.

[0055] Furthermore, the voltage adjustment process is not limited to being performed after each substrate W is processed, but may be performed as needed. For example, the control unit 90 may be configured to perform the voltage adjustment process first after starting up or performing maintenance on the substrate processing device 1, and not perform the voltage adjustment process in subsequent substrate processing. Alternatively, the control unit 90 may be configured to perform the voltage adjustment process when the processing liquid L is filled into the processing liquid source 72.

[0056] In the voltage adjustment process, once the voltage to be applied has been adjusted, the control unit 90 closes the valves 81v and 83v to end the voltage adjustment process and proceeds to the substrate processing, which is the etching process (steps S3 to S7). In the etching process, the control unit 90 first operates the rotating unit 60 to rotate the substrate W and the first electrode 41 (step S3). At this time, the substrate rotating unit 61 rotates the substrate W in a predetermined direction and at a set target rotation speed for the substrate. The electrode rotating unit 44 rotates the first electrode 41 in the opposite direction to the rotation of the substrate W and at a set target rotation speed for the electrode.

[0057] Furthermore, the control unit 90 opens the valve 71v of the processing liquid supply path 71, allowing the processing liquid L from the processing liquid source 72 to flow into the nozzle 31, and supplies the processing liquid L to the substrate W from the discharge port 31a of the nozzle 31 (step S4). The processing liquid L that falls from the discharge port 31a passes through each through-hole 413 of the first electrode 41 and hits the surface of the substrate W. Then, due to the centrifugal force accompanying the rotation of the substrate W and the opposing part 411, the processing liquid L wets and spreads radially outward of the substrate W. As a result, the entire electrode surface 411a of the first electrode 41 and the entire surface of the substrate W come into contact with the processing liquid L in the processing space PS.

[0058] The control unit 90 operates the power supply unit 40 to apply a predetermined output voltage (for example, 2V) from the power supply 43 to the first electrode 41 and the second electrode 42 that are in contact with the processing liquid L (step S5). As a result, the first electrode 41 and the second electrode 42 conduct through the processing liquid L, electrolyzing the processing liquid L. During electrolysis, OH radicals are generated in the processing liquid L near the electrode surface 411a of the first electrode 41. The OH radicals react with the resist film A, which is the target of removal on the substrate W, thereby separating the resist film from the substrate W. The substrate processing apparatus 1 can uniformly remove the resist film from the entire surface of the substrate W using the opposing parts 411 that face the entire surface of the substrate W.

[0059] The control unit 90 measures the duration of the etching process as the electrolysis of the processing solution L begins and determines whether a predetermined set period has elapsed (step S6). The set period is determined by experiments, simulations, etc., to be the period during which the resist film on the substrate W is removed by OH radicals. The substrate processing apparatus 1 can reliably remove the resist film by continuing the relative rotation of the substrate W and the first electrode 41, the supply of the processing solution L, and the supply of power (electrolysis) to the processing solution L until the etching process has elapsed.

[0060] When the etching process has exceeded the set period, the control unit 90 terminates the etching process (step S7). At this time, the control unit 90 stops supplying power to the first electrode 41 and the second electrode 42, and also stops supplying the processing liquid L to the nozzle 31 by closing the valve 71v.

[0061] Subsequently, the control unit 90 performs a rinsing and cleaning process of the substrate W as a substrate treatment to drain the processing liquid L remaining on the surface of the substrate W (step S8). In the rinsing and cleaning process, the valve 73v is opened, and while the substrate W is rotated by the rotating unit 60, the rinsing liquid from the rinsing liquid source 74 is introduced into the nozzle 31, and the rinsing liquid is supplied to the substrate W from the discharge port 31a of the nozzle 31. The rinsing liquid wets and spreads on the surface of the substrate W due to the centrifugal force of the rotation, and the processing liquid L is discharged from the surface of the substrate W.

[0062] After the rinsing process, the control unit 90 performs a spin drying process as a substrate treatment to dry the rinsing liquid on the surface of the substrate W (step S9). In the spin drying process, the substrate W is rotated by the rotating unit 60 to dry the rinsing liquid on the surface of the substrate W. In addition, in the substrate treatment, before the spin drying process, a drying liquid, which is the treatment liquid L, may be supplied from the liquid supply unit 30 to the surface of the substrate W to replace the rinsing liquid with the drying liquid. When this spin drying process is completed, the substrate treatment of the substrate W housed in the treatment container 10 is completed.

[0063] Finally, the control unit 90 releases the holding unit 20 from holding the substrate W, opens the gate valve 12 to allow the transport device 2 to enter the processing container 10, and transfers the substrate W to the transport device 2, thereby removing the substrate W from inside the processing container 10 (step S10). As a result, the substrate processing apparatus 1 can obtain a substrate W with the resist film removed in good condition.

[0064] As described above, the substrate processing apparatus 1 and substrate processing method apply a voltage to the first electrode 41 and the second electrode 42 while the first electrode 41 and the substrate W are in contact with the processing liquid L supplied from the liquid supply unit 30. As a result, OH radicals are generated in the processing liquid L near the first electrode 41, and these OH radicals can be smoothly applied to the target A on the substrate W. This allows the substrate processing apparatus 1 and substrate processing method to efficiently remove the target A from the surface of the substrate W. Furthermore, by not using sulfuric acid, the substrate processing apparatus 1 eliminates the processing required for the disposal of sulfuric acid, thereby reducing the environmental burden.

[0065] Furthermore, the substrate processing apparatus 1 can easily spread the processing liquid L supplied to the surface of the substrate W across the entire surface by rotating at least one of the first electrode 41 and the substrate W using the rotating part 60. In addition, the first electrode 41 has at least one layer of gold, palladium, carbon, or boron-doped diamond (BDD) on its electrode surface 411a, which increases the oxygen overpotential and allows for the easy generation of OH radicals in the processing liquid L. In particular, when the first electrode 41 is the anode, applying BDD makes it possible to further improve the efficiency of OH radical generation by the first electrode 41. In addition, the opposing parts 411 and 411A of the first electrode 41 have holes (through holes 413, mesh) that allow the processing liquid L discharged from the nozzle 31 above to pass through, enabling a stable supply of the processing liquid L to the surface of the substrate W.

[0066] Furthermore, the substrate processing apparatus 1 and substrate processing method can promote the electrolysis of the processing solution L by using an aqueous solution containing an electrolyte as the processing solution L. In particular, by including at least one of HF, HCl, NH4OH, TMAH, H2O2, H2SO4, H3PO4, and HNO3 as the aqueous solution, sufficient OH radicals can be generated.

[0067] Furthermore, the substrate processing apparatus 1 and substrate processing method can accurately adjust the voltage applied by the power supply unit 40 by detecting OH radicals generated in the processing liquid L separately from the processing container 10 using the detection unit 80. In particular, the substrate processing apparatus 1 can easily detect the amount of OH radicals by detecting the fluorescent substance generated by the reaction of OH radicals in the reactor 84 using a detection mechanism 86 that optically detects the substance. By applying terephthalic acid as the reaction liquid, the substrate processing apparatus 1 becomes fluorescent when it reacts with OH radicals, allowing for stable detection of the amount of OH radicals.

[0068] It should be noted that the substrate processing apparatus 1 and substrate processing method of this disclosure are not limited to the embodiments described above, and various modifications are possible. For example, in the above description, the substrate processing apparatus 1 used a resist film as the target A for removal, but similar substrate processing can also be performed on metal films, metal nitride films, and polymer residues on the surface of the substrate W. For example, the metal film consists of at least one of W, TiN, Co, Ni, Ru, Mo, and Al, and is effectively removed by OH radicals generated in the processing solution L.

[0069] The following describes the substrate processing apparatus 1 and substrate processing method related to other modifications, with reference to Figures 5 to 11.

[0070] As shown in the second modified example in Figure 5(A), the first electrode 41 may have a facing portion 411B that partially covers the surface of the substrate W, and the electrode rotating portion 44 (see Figure 1) may rotate the facing portion 411B. The facing portion 411B may be formed, for example, as an elongated rectangular flat plate extending beyond the diameter of the substrate W, and can face the entire surface of the substrate W as it rotates. In addition, the processing liquid L discharged from the nozzle 31 is supplied to the surface of the substrate W when the facing portion 411B is not facing the discharge port 31a. Even in this case, the power supply unit 40 can effectively remove the target material A from the substrate W by generating OH radicals near the facing portion 411B through power supply.

[0071] As shown in the third modified example in Figure 5(B), the first electrode 41 may have a fan-shaped opposing portion 411C that is narrow in the center and wide at the outer edge, and the opposing portion 411C may be rotated by the electrode rotating portion 44. By applying the opposing portion 411C in this way, the opposing portion 411C will face the surface near the outer edge of the substrate W for a longer period, and the target to be removed A near the outer edge of the substrate W can be removed more stably.

[0072] As shown in the fourth modified example in Figure 6, the rotating unit 60 may have a fixed structure 48 for fixing the first electrode 41, without the electrode rotating unit 44 (see Figure 1). In this case, the rotating unit 60 rotates the substrate W with the substrate rotating unit 61, spreading the processing liquid L supplied to the surface of the substrate W across the entire surface of the substrate W. The power supply unit 40 can generate OH radicals in the processing liquid L by applying a voltage to the first electrode 41 via the fixed structure 48. In short, the substrate processing apparatus 1 is not particularly limited in terms of the means for supplying the processing liquid L to the entire surface of the substrate W, as long as it can generate OH radicals across the entire surface of the substrate W. For example, even if the rotating unit 60 has an electrode rotating unit 44 but does not have a substrate rotating unit 61 (i.e., does not rotate the substrate W), the processing liquid L can still be spread on the surface of the substrate W as the first electrode 41 rotates.

[0073] As shown in Figure 7(A), the first electrode 41A according to the fifth modified example is configured to remove the target A near the outer edge of the substrate W, rather than removing the target A from the entire surface of the substrate W as in the above embodiment. Specifically, the first electrode 41A has a connecting portion 415 fixed to the fixing structure 48 and a projection 416 supported by the connecting portion 415 that protrudes briefly above the surface of the substrate W. The projection 416 is set to a length that can face only the outer edge of the substrate W and is close to a part of the circumferential direction of the outer edge of the substrate W. The substrate processing apparatus 1 rotates the substrate W with the rotating portion 60 (substrate rotating portion 61) and supplies processing liquid L to the surface of the substrate W from the nozzle 31, and also applies voltage to the first electrode 41A and the second electrode 42 with the power supply portion 40. As a result, the protrusion 416 of the first electrode 41A generates OH radicals in the processing liquid L near the outer edge of the substrate W, and these OH radicals effectively remove the material to be removed near the outer edge.

[0074] As shown in Figure 7(B), the first electrode 41B according to the sixth modified example has a ring portion 417 that circles the vicinity of the outer edge of the substrate instead of a protrusion 416 in order to remove the target material A near the outer edge of the substrate W. Even in this case, the substrate processing apparatus 1 can effectively remove the target material near the outer edge of the substrate W.

[0075] As shown in Figure 8, the substrate processing apparatus 1 according to the seventh modified example has a flow channel 412a formed inside the electrode shaft portion 412 of the first electrode 41C, and the protruding end of the nozzle 31 is inserted into this flow channel 412a. The flow channel 412a communicates with an opening formed in the center of the opposing portions 411, 411A to 411C of the first electrode 41. The liquid supply unit 30 and the power supply unit 40 cause the processing liquid L discharged from the discharge port 31a of the nozzle 31 to flow into the processing space PS through the opening. In this case, the electrode moving unit 45 is configured to move the nozzle 31 and the first electrode 41 together.

[0076] Even with this configuration, where the processing liquid L is supplied through the inside of the electrode shaft portion 412, the substrate processing apparatus 1 can stably supply the processing liquid L to the processing space PS between the electrode surface 411a and the surface of the substrate W, and perform electrolysis of the processing liquid L. Therefore, the OH radicals generated near the first electrode 41 can effectively remove the target material A from the substrate W. In particular, this configuration eliminates the need to provide a through hole 413 in the opposing portion 411, thus reliably preventing splashing caused by the processing liquid L hitting the upper surface of the opposing portion 411.

[0077] As shown in Figure 9, the substrate processing apparatus 1A according to the eighth modified example is configured to apply a voltage to the first electrode 41 and the second electrode 42 while the substrate W is immersed in the processing liquid L. Specifically, the holding part 20 has a chuck mechanism 22 for vacuum adsorption of the substrate W, and a frame part 23 that protrudes radially outward from the substrate W and above the substrate W, and also wraps around in an annular shape in the circumferential direction. As a result, the mounting surface on which the substrate W is placed and the inside of the frame part 23 become a storage space 24 capable of storing the processing liquid L.

[0078] The liquid supply unit 30 has a nozzle 31 that supplies the processing liquid L above the storage space 24. The nozzle 31 retracts from the cup 50 after supplying the processing liquid L. Alternatively, the nozzle 31 may remain above the storage space 24 during the etching process and replenish the processing liquid L in the storage space 24 when the amount decreases.

[0079] The power supply unit 40 includes a first electrode 41 having a facing portion 411 that faces the substrate W, and a second electrode 42 that is inserted into the storage space 24 horizontally outside the first electrode 41. The first electrode 41 is connected to the electrode moving portion 45. In this modified example, the rotating portion 60 (substrate rotating portion 61 and electrode rotating portion 44) is not provided, but the substrate processing apparatus 1A may also be configured to include a rotating portion 60 for rotating the substrate W and the first electrode 41.

[0080] In the substrate processing apparatus 1A configured in this way, when a voltage is applied to the first electrode 41 and the second electrode 42 by the power supply 43 while the processing liquid L is stored in the storage space 24, OH radicals are generated near the electrode surface 411a of the first electrode 41. Therefore, even in this substrate processing apparatus 1A, the target substance A on the surface of the substrate W can be removed by the generated OH radicals. In particular, the substrate processing apparatus 1A can remove the target substance A more uniformly by suppressing turbulence of the processing liquid L during electrolysis.

[0081] The substrate processing apparatus 1B according to the ninth modified example shown in Figures 10(A) to 10(C) is configured to clean the first electrode 41, which has undergone etching treatment, at the same time as the rinsing and cleaning process of the substrate W. Specifically, the substrate processing apparatus 1B has a support arm 45a that supports the first electrode 41 as an electrode moving part 45, and an arm rotating part 45b that rotates the support arm 45a. As shown in Figure 10(A), during the etching process, the substrate processing apparatus 1B positions the first electrode 41 on the vertically upper side of the substrate W and in the vicinity of the substrate W, thereby generating OH radicals in the processing liquid L and removing the target A from the substrate W.

[0082] After the etching process, the substrate processing apparatus 1B rotates the support arm 45a using the arm rotation unit 45b to move the first electrode 41 to the electrode retraction position. This exposes the surface of the substrate W, and allows the first electrode 41 to perform other processing in the electrode retraction position.

[0083] The substrate processing apparatus 1B performs the rinse cleaning process and spin drying process described above on the exposed substrate W (see also Figure 4). For example, in the rinse cleaning process, the substrate processing apparatus 1B moves the cleaning nozzle 33 that discharges the rinse liquid (DIW) above the substrate W and rotates the substrate W while supplying the rinse liquid.

[0084] On the other hand, the first electrode 41, which is positioned in the electrode retraction position, is subjected to an electrode rinsing process and an air blow drying process in sequence. For example, in the electrode rinsing process, the substrate processing apparatus 1B moves a bar nozzle 34 that discharges rinsing liquid (DIW) above (or below) the first electrode 41 and slides the bar nozzle 34 while supplying the rinsing liquid. This allows the first electrode 41 used for electrolysis to be cleaned. In the subsequent air blow drying process, the substrate processing apparatus 1B also moves a blower (not shown) above (or below) the first electrode 41 to remove the rinsing liquid adhering to the first electrode 41. In this way, the substrate processing apparatus 1B cleans the first electrode 41, thereby increasing its durability and allowing it to be used for a long period of time.

[0085] Furthermore, as shown in the 10th modified example in Figure 11, the substrate processing apparatus 1C may be configured as a batch-type apparatus that processes multiple substrates W simultaneously. The batch-type substrate processing apparatus 1C has a processing tank 15 (processing container) that stores processing liquid L and can accommodate multiple substrates W, and multiple substrates W are immersed together in the processing liquid L stored in the processing tank 15. For example, each substrate W is held so as to extend along the vertical direction by a holding part (not shown). In addition, the substrate processing apparatus 1C has a liquid supply part (not shown) that supplies processing liquid L into the processing tank 15.

[0086] The substrate processing apparatus 1C then places a first electrode 41 near each of the held substrates W. The second electrode 42 is placed at an appropriate position within the processing tank 15. As a result, the substrate processing apparatus 1C can generate OH radicals for each of the multiple first electrodes 41 by applying an appropriate voltage from the power supply 43 to the first electrode 41 and the second electrode 42. The substrates W placed adjacent to each first electrode 41 will have the target material A effectively removed by the OH radicals.

[0087] The substrate processing apparatus 1 and substrate processing method according to the embodiments disclosed herein are illustrative in all respects and are not restrictive. The embodiments can be modified and improved in various ways without departing from the scope and spirit of the appended claims. The matters described in the above embodiments can be otherwise configured and combined in a non-consistent manner.

[0088] This application claims priority to Basic Application No. 2022-095874, filed with the Japan Patent Office on June 14, 2022, the entire contents of which are incorporated herein by reference. [Explanation of symbols]

[0089] 1. Substrate processing apparatus 20 Holding part 30 Liquid supply section 41 1st electrode 42 2nd electrode 43 Power supply 90 Control Unit A: Items to be removed L Treatment solution W board

Claims

1. A substrate processing apparatus for removing the target material from a substrate using a processing solution, A holding portion for holding the substrate, A liquid supply unit that supplies the processing liquid to the substrate held by the holding unit, An electrode is positioned at a distance from the substrate held in the holding portion and is in contact with the processing liquid supplied from the liquid supply portion, A power supply for applying voltage to the aforementioned electrode, The system comprises the liquid supply unit and the control unit that controls the power supply, The control unit applies a voltage to the electrode while the electrode and the substrate are in contact with the processing liquid supplied from the liquid supply unit, thereby generating OH radicals in the processing liquid and applying the OH radicals to the object to be removed. The electrode includes a first electrode and a second electrode, The first electrode comes into contact with the processing liquid that flows between the first electrode and the substrate. The second electrode is located further from the substrate than the first electrode and is electrically connected to the first electrode through the processing liquid continuously supplied by the liquid supply unit. Circuit board processing equipment.

2. The electrode and the substrate held in the holding part have a rotating part that rotates at least one of them relative to the other, The control unit rotates the rotating part at a target rotation speed set during substrate processing. The substrate processing apparatus according to claim 1.

3. The first electrode has at least one layer of gold, palladium, carbon, and boron-doped diamond on its electrode surface. The substrate processing apparatus according to claim 1.

4. The first electrode is an anode, The anode has boron-doped diamond on its electrode surface. The substrate processing apparatus according to claim 3.

5. The distance between the first electrode and the substrate held by the holding part is set to a range of 0.5 mm to 5 mm. The substrate processing apparatus according to claim 1.

6. The first electrode has a facing portion that faces the entire surface of the substrate held by the holding portion, The opposing portion has a plurality of holes through which the processing liquid discharged from the liquid supply portion passes. The substrate processing apparatus according to claim 1.

7. It has a rotating part for rotating the first electrode, The first electrode has a rectangular opposing portion that extends from the center to the outer circumference of the substrate held in the holding portion. The substrate processing apparatus according to claim 1.

8. It has a rotating part for rotating the first electrode, The first electrode has fan-shaped opposing portions whose width in the circumferential direction widens from the center of the substrate toward the outer periphery. The substrate processing apparatus according to claim 1.

9. It has a rotating part that rotates the substrate, The first electrode has a projection that faces only a portion of the circumferential edge of the outer edge of the substrate held by the holding portion. The substrate processing apparatus according to claim 1.

10. The first electrode has a ring portion that extends circumferentially along the outer edge of the substrate held by the holding portion. The substrate processing apparatus according to claim 1.

11. The first electrode has a facing portion that faces the surface of the substrate held by the holding portion, and an electrode shaft portion that supports the facing portion. The liquid supply unit supplies the processing liquid between the opposing portion and the surface of the substrate via a flow path inside the electrode shaft portion. The substrate processing apparatus according to claim 1.

12. The aforementioned processing solution is an aqueous solution containing an electrolyte. The substrate processing apparatus according to claim 1.

13. The aqueous solution is HF, HCl, NH ４ OH, TMAH, H ２ O ２ , H ２ SO ４ , H ３ PO ４ HNO ３ Including at least one of the following: The substrate processing apparatus according to claim 12.

14. The object to be removed is the resist film formed on the surface of the substrate, or the polymer residue remaining on the surface of the substrate. The substrate processing apparatus according to claim 1.

15. The target of removal is at least one of the following: a metal film containing at least one of W, Co, Ni, Ru, Mo, and Al, and a metal nitride film containing TiN. The substrate processing apparatus according to claim 1.

16. A processing container for processing the aforementioned substrate, The system includes a detection unit provided separately from the processing container, into which the processing liquid supplied to the processing container flows separately, The detection unit detects the OH radicals generated in the processing liquid by applying the same voltage to the incoming processing liquid as the electrodes of the processing container. A substrate processing apparatus according to any one of claims 1 to 15.

17. The detection unit comprises a reactor that applies a voltage to a mixture obtained by mixing a reaction solution, which is produced by reacting with the generated OH radicals to produce a fluorescent substance, with the processing solution, and a detection mechanism that optically detects the fluorescent substance produced in the reactor. The substrate processing apparatus according to claim 16.

18. The reaction solution is terephthalic acid. The substrate processing apparatus according to claim 17.

19. A substrate processing method in which the target to be removed from the substrate is removed with a processing solution, A step of holding the substrate with the holding part, A step of supplying the processing liquid to the substrate held in the holding part, The process includes the step of applying a voltage from a power supply to electrodes that are arranged at intervals relative to the substrate held in the holding portion, The electrode includes a first electrode and a second electrode, In the step of supplying the processing liquid, the first electrode and the substrate are brought into contact with the processing liquid that has been introduced between the first electrode and the substrate, and the second electrode is located further away from the substrate than the first electrode, and is electrically connected to the first electrode through the processing liquid that is continuously supplied by the liquid supply unit. In the step of applying the voltage, OH radicals are generated in the processing liquid that comes into contact with the electrode as the voltage is applied, and these OH radicals are applied to the object to be removed. Substrate processing method.

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