Substrate processing method and substrate processing apparatus

Abstract

To provide a substrate processing method that can prevent inert gas to be supplied to processing liquid in a processing tank from affecting uniformity of processing within a plane of a substrate or uniformity of processing between a plurality of substrates while keeping the dissolved oxygen concentration of processing liquid within a target concentration range.SOLUTION: A substrate processing method is executed in a substrate processing apparatus 100. In the substrate processing apparatus 100, processing liquid LQ is circulated between a processing tank 105 and an outer tank 110. The substrate processing method includes: a process S2 of supplying first inert gas GA1 to the processing liquid LQ of the processing tank 105 while holding a flow rate of the first inert gas GA1 to a constant level; a process S5 of measuring the dissolved oxygen concentration of the processing liquid LQ; and a process S7 of supplying gas to the processing liquid LQ stored in the outer tank 110. In the process S7, by adjusting the gas flow rate on the basis of the dissolved oxygen concentration of the processing liquid LQ in the state where the flow rate of the first inert gas GA1 is held to a constant level, the dissolved oxygen concentration of the processing liquid LQ in the processing tank 105 is adjusted.SELECTED DRAWING: Figure 10

Description

Technical Field

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

Background Art

[0002] The substrate processing apparatus described in Patent Document 1 includes a processing tank, an outer tank, a first gas supply unit, and a second gas supply unit. The processing tank immerses a substrate in a processing liquid. The outer tank surrounds the processing tank and receives the processing liquid that overflows from the processing tank. The first gas supply unit supplies an inert gas to the processing liquid stored in the processing tank. The second gas supply unit supplies an inert gas to the processing liquid stored in the outer tank from an opening disposed inside the outer tank. Thus, by supplying an inert gas into the etching liquid and dissolving it in the processing liquid, the oxygen concentration of the processing liquid stored in the outer tank can be reduced. As a result, the oxygen concentration of the processing liquid stored in the processing tank connected to the outer tank via a circulation path can also be reduced, so that the uniformity of the etching amount in the depth direction of the holes formed in the wafer can be improved.

[0003] Further, the substrate processing apparatus includes an oxygen concentration measurement unit. The oxygen concentration measurement unit measures the oxygen concentration of the processing liquid extracted from the processing tank with an oxygen concentration sensor. Thereby, the oxygen concentration measurement unit can measure the oxygen concentration of the processing liquid stored in the processing tank.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the substrate processing apparatus described in Patent Document 1, the control unit controls the amount of inert gas supplied from the first gas supply unit to the processing liquid in the processing tank based on the oxygen concentration of the processing liquid measured by an oxygen concentration sensor. In this way, when feedback control is performed, the amount of inert gas supplied to the processing liquid in the processing tank is not constant but is adjusted.

[0006] As a result of diligent research, the inventors of the present invention have found that even if the oxygen concentration (dissolved oxygen concentration) of the treatment solution in the treatment tank is within the target concentration range, adjusting the amount of inert gas supplied to the treatment solution in accordance with the oxygen concentration may affect the uniformity of the treatment within the plane of the substrate and / or the uniformity of the treatment between multiple substrates.

[0007] The object of the present invention is to provide a substrate processing method and a substrate processing apparatus that can keep the dissolved oxygen concentration of the processing solution within a target concentration range while suppressing the effect of the inert gas supplied to the processing solution in the processing tank on the uniformity of processing within the plane of the substrate and / or the uniformity of processing between multiple substrates. [Means for solving the problem]

[0008] According to one aspect of the present invention, a substrate processing method is performed in a substrate processing apparatus. The substrate processing apparatus comprises a processing tank for storing a processing liquid into which a substrate is immersed, and an outer tank disposed outside the processing tank for storing the processing liquid. In the substrate processing apparatus, the processing liquid is circulated between the processing tank and the outer tank. The substrate processing method includes the steps of: supplying the first inert gas to the processing liquid stored in the processing tank while maintaining a constant flow rate of the first inert gas; measuring the dissolved oxygen concentration of the processing liquid; and supplying gas to the processing liquid stored in the outer tank. In the step of supplying gas, while maintaining a constant flow rate of the first inert gas, the dissolved oxygen concentration of the processing liquid stored in the processing tank is adjusted by adjusting the flow rate of the gas based on the dissolved oxygen concentration of the processing liquid.

[0009] In one embodiment of the present invention, it is preferable that a second inert gas and air are used as the gas. In the step of supplying the gas, it is preferable to adjust the dissolved oxygen concentration of the processing liquid by adjusting the ratio of the flow rate of the second inert gas to the flow rate of the air.

[0010] In one embodiment of the present invention, the gas is preferably a second inert gas. In the step of supplying the gas, it is preferable to decrease the dissolved oxygen concentration of the processing liquid by increasing the flow rate of the second inert gas, and to increase the dissolved oxygen concentration of the processing liquid by decreasing the flow rate of the second inert gas.

[0011] In one embodiment of the present invention, the gas is preferably air. In the step of supplying the gas, it is preferable to decrease the dissolved oxygen concentration of the processing liquid by decreasing the flow rate of the air, and to increase the dissolved oxygen concentration of the processing liquid by increasing the flow rate of the air.

[0012] In one embodiment of the present invention, the outer tank preferably has a plurality of storage sections that communicate with each other. In the step of supplying the gas in the outer tank, it is preferable to supply the gas to the processing liquid stored in the storage section with the largest capacity among the plurality of storage sections.

[0013] In one embodiment of the present invention, it is preferable that piping for introducing the processing liquid into the processing tank is connected to the bottom of the largest-capacity storage section. In the step of supplying the gas in the outer tank, it is preferable to supply the gas from the bottom of the largest-capacity storage section toward the liquid surface of the processing liquid.

[0014] According to another aspect of the present invention, the substrate processing apparatus comprises a processing tank, an outer tank, a processing liquid introduction unit, a first gas supply unit, a second gas supply unit, a gas adjustment unit, a measuring unit, and a gas control unit. The processing tank stores a processing liquid into which the substrate is immersed. The outer tank is located outside the processing tank, and the processing liquid that overflows from the processing tank flows into it. The processing liquid introduction unit introduces the processing liquid stored in the outer tank into the processing tank. The first gas supply unit supplies the inert gas to the processing liquid stored in the processing tank while maintaining a constant flow rate of the inert gas. The second gas supply unit supplies gas to the processing liquid stored in the outer tank. The gas adjustment unit adjusts the flow rate of the gas supplied to the second gas supply unit. The measuring unit measures the dissolved oxygen concentration of the processing liquid. The gas control unit adjusts the flow rate of the gas by controlling the gas adjustment unit based on the dissolved oxygen concentration of the processing liquid, while the flow rate of the inert gas is kept constant, thereby adjusting the dissolved oxygen concentration of the processing liquid stored in the processing tank. [Effects of the Invention]

[0015] According to the present invention, it is possible to keep the dissolved oxygen concentration of the processing solution within a target concentration range while suppressing the effect of the inert gas supplied to the processing solution in the processing tank on the uniformity of processing within the plane of the substrate and / or the uniformity of processing between multiple substrates. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic cross-sectional view showing a substrate processing apparatus according to an embodiment of the present invention. [Figure 2] This graph shows the relationship between the dissolved oxygen concentration of the processing solution and the amount of etching according to this embodiment. [Figure 3] This graph shows the relationship between the supply time of the first inert gas according to this embodiment and the dissolved oxygen concentration of the treatment liquid. [Figure 4] (a) is a perspective view showing the substrate according to this embodiment before it is immersed in the processing solution. (b) is a perspective view showing the substrate according to this embodiment after it has been immersed in the processing solution. [Figure 5]It is a schematic plan view showing a substrate processing apparatus according to the present embodiment. [Figure 6] It is a cross-sectional view taken along line VI-VI of FIG. 5. [Figure 7] It is a cross-sectional view taken along line VII-VII of FIG. 5. [Figure 8] It is a schematic plan view showing a first gas supply unit according to the present embodiment. [Figure 9] It is a schematic back view showing an introduction unit according to the present embodiment. [Figure 10] It is a flowchart showing a substrate processing method according to the present embodiment. [Figure 11] It is a schematic plan view showing a substrate processing apparatus according to the first modification of the present embodiment. [Figure 12] It is a schematic plan view showing a substrate processing apparatus according to the second modification of the present embodiment. [Figure 13] It is a schematic plan view showing a substrate processing apparatus according to the third modification of the present embodiment.

MODE FOR CARRYING OUT THE INVENTION

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and the description thereof will not be repeated. Also, in the drawings, for ease of understanding, the X-axis, Y-axis, and Z-axis are appropriately illustrated. The X-axis, Y-axis, and Z-axis are orthogonal to each other, the X-axis and Y-axis are parallel in the horizontal direction, and the Z-axis is parallel in the vertical direction. Note that "plan view" indicates viewing the object from directly above vertically. "Back view" indicates viewing the object from directly below vertically.

[0018] Referring to FIGS. 1 to 10, a substrate processing apparatus 100 and a substrate processing method according to an embodiment of the present invention will be described. First, referring to FIG. 1, the substrate processing apparatus 100 will be described. FIG. 1 is a schematic cross-sectional view showing the substrate processing apparatus 100. The substrate processing apparatus 100 shown in FIG. 1 is of a batch type and processes a plurality of substrates W collectively with a processing liquid LQ. The substrate processing apparatus 100 can also process one substrate W.

[0019] The substrate processing apparatus 100 comprises a processing tank 105, an outer tank 110, a first lid 111, a second lid 112, a substrate holding section 120, a processing liquid introduction section 125, a drainage section 170, a first gas adjustment section 180, a first gas supply section 200, a third gas supply section 210, a measuring section 245, and a control device 220.

[0020] The processing tank 105 stores a processing liquid LQ in which multiple substrates W are immersed. The processing tank 105 is capable of accommodating multiple substrates W. The processing tank 105 processes multiple substrates W by immersing them in the processing liquid LQ.

[0021] The treatment solution LQ is, for example, an etching solution. For example, the treatment solution LQ is used to etch a polysilicon film formed on the substrate W. In this embodiment, as an example, the treatment solution LQ is alkaline. An alkaline treatment solution LQ is, for example, an aqueous solution containing tetramethylammonium hydroxide (TMAH), an aqueous solution containing trimethyl-2-hydroxyethylammonium hydroxide (TMY), ammonium hydroxide (ammonia water), or a mixture of ammonia and hydrogen peroxide (SC1). The treatment solution LQ may also be acidic. An acidic treatment solution LQ is, for example, hydrofluoric acid (HF), hydrofluoric acid (a mixture of hydrofluoric acid and nitric acid (HNO3)), phosphoric acid (H3PO4), sulfuric acid, hydrochloric acid, sulfuric acid and hydrogen peroxide mixture (SPM), hydrochloric acid and hydrogen peroxide mixture (SC2), or a mixed acid.

[0022] The first lid 111 covers the upper opening 106a of the processing tank 105. The upper opening 106a opens upward in the vertical direction D. The first lid 111 includes a pair of hinged doors 51. The upper opening 106a is opened when one hinged door 51 opens in the direction of arrow a1 and the other hinged door 51 opens in the direction of arrow a2. Note that Figure 1 shows the pair of hinged doors 51 in a closed state.

[0023] The outer tank 110 is positioned outside the treatment tank 105. The outer tank 110 surrounds the treatment tank 105. The treatment liquid LQ that overflows from the treatment tank 105 flows into the outer tank 110. The height of the upper edge of the outer tank 110 is higher than the height of the upper edge of the treatment tank 105.

[0024] The second lid 112 covers the upper opening 110a of the outer tank 110. The upper opening 110a opens upward in the vertical direction D. A gap 110b exists between the second lid 112 and the upper end of the processing tank 105. The processing liquid LQ overflowing from the processing tank 105 flows into the outer tank 110 through the gap 110b. The first lid 111 covers the second lid 112. Note that the substrate processing apparatus 100 does not necessarily have to be equipped with the second lid 112. In this case, the first lid 111 covers the upper opening 110a of the outer tank 110.

[0025] The substrate holding section 120 holds multiple substrates W. The substrate holding section 120 can also hold a single substrate W. The substrate holding section 120 immerses multiple substrates W, which are aligned at intervals, in the processing liquid LQ stored in the processing tank 105.

[0026] Specifically, the substrate holder 120 moves up or down along the vertical direction D while holding multiple substrates W. The substrate holder 120 includes a main plate 122 and multiple holding rods 124. The main plate 122 is a plate that extends in the vertical direction D. The multiple holding rods 124 extend in the first direction D10 (Figure 4). The multiple substrates W are aligned with a gap between them, and their lower edges are in contact with the multiple holding rods 124 to hold them in an upright position (vertical position).

[0027] The substrate holding section 120 may further include a lifting unit 126. The lifting unit 126 raises and lowers the main plate 122 between a processing position (shown in Figure 4(b)) where the multiple substrates W held by the holding rod 124 are located inside the processing tank 105, and a retracted position (shown in Figure 4(a)) where the multiple substrates W held by the holding rod 124 are located above the processing tank 105. As a result, when the main plate 122 is moved to the processing position by the lifting unit 126, the multiple substrates W held by the holding rod 124 are immersed in the processing liquid LQ. This allows the multiple substrates W to be processed.

[0028] The first gas supply unit 200 supplies the first inert gas GA1 to the processing liquid LQ stored in the processing tank 105. In this embodiment, the first gas supply unit 200 supplies the first inert gas GA1 to the processing liquid LQ stored in the processing tank 105 while maintaining a constant flow rate of the first inert gas GA1 for at least the processing period of the substrate W. The first inert gas GA1 is, for example, nitrogen or argon. Specifically, the first gas supply unit 200 supplies bubbles BB1 of the first inert gas GA1 to the processing liquid LQ stored in the processing tank 105. In this embodiment, the first gas supply unit 200 supplies bubbles BB1 of the first inert gas GA1 to the processing liquid LQ stored in the processing tank 105 while maintaining a constant flow rate of the first inert gas GA1 for at least the processing period of the substrate W. A large number of bubbles BB1 are supplied to the processing liquid LQ.

[0029] More specifically, the first gas supply unit 200 is located inside the processing tank 105. The first gas supply unit 200 includes at least one first gas supply pipe 21. In this embodiment, the first gas supply unit 200 includes a plurality of first gas supply pipes 21. The plurality of first gas supply pipes 21 are located inside the processing tank 105. The plurality of first gas supply pipes 21 are located on the bottom side of the processing tank 105. The plurality of first gas supply pipes 21 are immersed in the processing liquid LQ. Each of the plurality of first gas supply pipes 21 has a plurality of first discharge holes H1. In each of the plurality of first gas supply pipes 21, each first discharge hole H1 is provided at the top of the first gas supply pipe 21. In this case, for example, the first discharge hole H1 faces upward in the vertical direction D.

[0030] Each of the multiple first gas supply pipes 21 supplies bubbles BB1 to the processing liquid LQ from each of the multiple first discharge holes H1 by discharging a first inert gas GA1 from each of the multiple first discharge holes H1. Specifically, each of the multiple first gas supply pipes 21 supplies bubbles BB1 to the processing liquid LQ from below the substrate W, with each of the multiple first discharge holes H1, when the substrate W is immersed in the processing liquid LQ.

[0031] The first gas supply pipe 21 is, for example, a bubbler pipe. The material of the first gas supply pipe 21 is, for example, quartz or resin. The resin is, for example, a corrosion-resistant resin such as polyetheretherketone (PEEK), perfluoroalkoxyalkane (PFA), and polytetrafluoroethylene (PTFE). The diameter of the first gas supply pipe 21 is not particularly limited, but for example it is about 6.0 mm. The diameter of the first discharge port H1 is not particularly limited, but for example it is about 0.2 mm. The diameter of the first discharge port H1 may be determined, for example, by considering the relationship between the laminar flow (described later) of the processing liquid LQ from the introduction section 130 and the bubbles BB1.

[0032] The first gas adjustment unit 180 can adjust the flow rate of the first inert gas GA1 supplied to the first gas supply unit 200. Specifically, the first gas adjustment unit 180 can adjust the amount of bubbles BB1 supplied by the first gas supply unit 200 to the processing liquid LQ by adjusting the flow rate of the first inert gas GA1 supplied to the first gas supply unit 200. More specifically, the first gas adjustment unit 180 can adjust the amount of bubbles BB1 supplied by each first gas supply pipe 21 to the processing liquid LQ from multiple first discharge holes H1 by adjusting the flow rate of the first inert gas GA1 supplied to each first gas supply pipe 21. The flow rate of the first inert gas GA1 is expressed as the flow rate per unit time.

[0033] In this embodiment, the first gas adjustment unit 180 maintains a constant flow rate of the first inert gas GA1 supplied to the first gas supply unit 200 for at least the processing period of the substrate W. In other words, the first gas adjustment unit 180 maintains a constant total flow rate of the first inert gas GA1 supplied to the plurality of first gas supply pipes 21 for at least the processing period of the substrate W. Maintaining a constant total flow rate indicates that the total flow rate is maintained at a target total flow rate. Here, the flow rate of the first inert gas GA1 supplied to one first gas supply pipe 21 is defined as the "individual flow rate". In this case, for example, the individual flow rates of the first inert gas GA1 supplied to the plurality of first gas supply pipes 21 are approximately equal. However, as long as the individual flow rate of the first inert gas GA1 in each first gas supply pipe 21 is constant, the individual flow rates of the first inert gas GA1 supplied to the plurality of first gas supply pipes 21 may be different.

[0034] Specifically, the first gas adjustment unit 180 supplies the first inert gas GA1, supplied from the first inert gas supply source K1, to a plurality of first gas supply pipes 21. The first inert gas supply source K1 stores the first inert gas GA1. In detail, the substrate processing apparatus 100 further comprises a plurality of pipes 181. Each of the plurality of pipes 181 is connected to a plurality of first gas supply pipes 21. The first gas adjustment unit 180 then supplies the first inert gas GA1, supplied from the inert gas supply source TKC, to each of the plurality of first gas supply pipes 21 from the plurality of pipes 181.

[0035] More specifically, the first gas adjustment unit 180 includes a plurality of gas flow rate adjustment mechanisms 182. Each of the plurality of gas flow rate adjustment mechanisms 182 is connected to a plurality of pipes 181. That is, one end of the pipe 181 is connected to the first gas supply pipe 21, and the other end of the pipe 181 is connected to the gas flow rate adjustment mechanism 182. Each of the plurality of gas flow rate adjustment mechanisms 182 is provided corresponding to a plurality of first gas supply pipes 21. The gas flow rate adjustment mechanism 182 supplies the first inert gas GA1 supplied from the first inert gas supply source K1 to the corresponding first gas supply pipe 21 via the corresponding pipe 181. In addition, the gas flow rate adjustment mechanism 182 can adjust the individual flow rates of the first inert gas GA1 supplied to the corresponding first gas supply pipe 21.

[0036] In this embodiment, the gas flow rate adjustment mechanism 182 maintains a constant individual flow rate of the first inert gas GA1 supplied to the corresponding first gas supply pipe 21, at least during the processing period of the substrate W. Maintaining a constant individual flow rate indicates that the individual flow rate is maintained at the target individual flow rate.

[0037] The third gas supply unit 210 supplies the third inert gas GA3 into the outer tank 110. The third gas supply unit 210 is located inside the outer tank 110. The third inert gas GA3 is, for example, nitrogen or argon. In this embodiment, the third inert gas GA3 is the same as the first inert gas GA1. Specifically, the third gas supply unit 210 includes a third gas supply pipe 25. The third gas supply pipe 25 is located inside the outer tank 110. The third gas supply pipe 25 has a plurality of second discharge holes H2. The third gas supply pipe 25 discharges the third inert gas GA3 into the outer tank 110 from each of the plurality of second discharge holes H2. The material of the third gas supply pipe 25 is, for example, quartz or resin. The resin is, for example, a corrosion-resistant resin such as PEEK, PFA, and PTFE. The diameter of the third gas supply pipe 25 is not particularly limited, but for example, it is about 6.0 mm. The diameter of the second discharge port H2 is not particularly limited, but for example, it is about 0.2 mm.

[0038] The processing liquid introduction unit 125 introduces the processing liquid LQ stored in the outer tank 110 into the processing tank 105. As a result, the processing liquid LQ circulates between the processing tank 105 and the outer tank 110.

[0039] The processing liquid introduction section 125 includes an introduction section 130 and a circulation section 140.

[0040] The introduction unit 130 introduces the processing liquid LQ into the processing tank 105. The introduction unit 130 is located inside the processing tank 105, below the first gas supply unit 200 (specifically, the first gas supply pipe 21).

[0041] Specifically, the introduction section 130 includes a plate 31. The plate 31 has a substantially flat shape. The plate 31 divides the inside of the processing tank 105, forming a processing chamber 113 and an introduction chamber 115. In other words, the processing tank 105 has a processing chamber 113 and an introduction chamber 115. The processing chamber 113 is a chamber inside the processing tank 105 that is above the plate 31. The first gas supply unit 200 is located in the processing chamber 113. The substrate W is also located in the processing chamber 113. The introduction chamber 115 is a chamber inside the processing tank 105 that is below the plate 31.

[0042] The plate 31 is positioned below the first gas supply unit 200. The plate 31 covers the bottom surface of the processing tank 105. The plate 31 is approximately perpendicular to the vertical direction D. The plate 31 has a plurality of processing liquid holes P. The processing liquid holes P penetrate the plate 31. The processing liquid holes P are arranged across the entire surface of the plate 31. The processing liquid holes P face upward in the vertical direction D.

[0043] Multiple first gas supply pipes 21 are positioned inside the processing tank 105, above the plate 31 and below the substrate W.

[0044] The introduction unit 130 introduces the processing liquid LQ into the processing tank 105 from multiple processing liquid holes P upwards, while the processing liquid LQ is stored in the processing tank 105. Therefore, the introduction unit 130 can generate a laminar flow of the processing liquid LQ supplied from the circulation unit 140. In other words, the introduction unit 130 introduces the processing liquid LQ into the processing tank 105 by generating a laminar flow of the processing liquid LQ. The laminar flow of the processing liquid LQ flows upwards from the multiple processing liquid holes P along a substantially vertical direction D.

[0045] Specifically, the introduction section 130 includes at least one discharge section 131 and at least one dispersion plate 132. The discharge section 131 is, for example, a nozzle or a tube. The dispersion plate 132 is, for example, substantially flat. The dispersion plate 132 is substantially perpendicular to the vertical direction D. The discharge section 131 and the dispersion plate 132 are arranged in the introduction chamber 115.

[0046] The discharge section 131 is located below the dispersion plate 132. The discharge section 131 faces the dispersion plate 132 in the vertical direction D. The discharge section 131 discharges the processing liquid LQ supplied from the circulation section 140 toward the dispersion plate 132. Therefore, the processing liquid LQ strikes the dispersion plate 132. As a result, the pressure of the processing liquid LQ is dispersed by the dispersion plate 132. In other words, the dispersion plate 132 disperses the pressure of the processing liquid LQ discharged by the discharge section 131. The processing liquid LQ, whose pressure has been dispersed by the dispersion plate 132, then spreads in a substantially horizontal direction in the introduction chamber 115. Furthermore, the processing liquid LQ is supplied to the processing chamber 113 as a laminar flow upward along the vertical direction D from each processing liquid hole P of the plate 31. In this way, the introduction section 130 has a flow rectification function for the processing liquid LQ by generating a laminar flow of the processing liquid LQ along the vertical direction D.

[0047] The circulation unit 140 circulates the treatment liquid LQ in the treatment tank 105 by supplying the treatment liquid LQ that overflows from the treatment tank 105 and flows into the outer tank 110 to the introduction unit 130.

[0048] Specifically, the circulation unit 140 includes circulation piping 141, a pump 142, a heater 143, a filter 144, a control valve 145, and a valve 146. The pump 142, heater 143, filter 144, control valve 145, and valve 146 are arranged in this order from upstream to downstream of the circulation piping 141.

[0049] The circulation piping 141 connects the outer tank 110 and the treatment tank 105. The circulation piping 141 then guides the treatment liquid LQ that overflows from the treatment tank 105 and flows into the outer tank 110 back into the treatment tank 105. In this way, the treatment liquid LQ flows through the circulation piping 141. Specifically, the upstream end of the circulation piping 141 is connected to the outer tank 110. Details of the connection position between the upstream end of the circulation piping 141 and the outer tank 110 will be described later with reference to Figure 6. On the other hand, the inlet 130 (specifically the discharge 131) is connected to the downstream end of the circulation piping 141. Therefore, the circulation piping 141 guides the treatment liquid LQ from the outer tank 110 to the inlet 130 (specifically the discharge 131). The circulation piping 141 corresponds to an example of the "piping for introducing treatment liquid into the treatment tank" of the present invention.

[0050] Pump 142 delivers the processing liquid LQ from the outer tank 110 to the processing tank 105 via the circulation piping 141. Specifically, pump 142 delivers the processing liquid LQ from the outer tank 110 to the discharge section 131 via the circulation piping 141. Therefore, the discharge section 131 discharges the processing liquid LQ supplied from the circulation piping 141. Filter 144 filters the processing liquid LQ flowing through the circulation piping 141.

[0051] The heater 143 heats the processing liquid LQ flowing through the circulation pipe 141. In other words, the heater 143 regulates the temperature of the processing liquid LQ. The adjustment valve 145 adjusts the flow rate of the processing liquid LQ supplied to the discharge section 131 by controlling the opening degree of the adjustment valve 145. Valve 146 opens and closes the circulation pipe 141.

[0052] The drainage section 170 discharges the treatment liquid LQ from the treatment tank 105. The drainage section 170 includes a drainage pipe 170a and a valve 170b. The drainage pipe 170a is connected to the bottom wall of the treatment tank 105. A valve 170b is located on the drainage pipe 170a. When the valve 170b opens, the treatment liquid LQ stored in the treatment tank 105 is discharged to the outside through the drainage pipe 170a. The discharged treatment liquid LQ is sent to a drainage treatment device (not shown) for processing.

[0053] The measuring unit 245 measures the dissolved oxygen concentration of the processing liquid LQ. Specifically, the measuring unit 245 is located outside the processing tank 105 and measures the dissolved oxygen concentration of the processing liquid LQ in the circulation piping 141. More specifically, the measuring unit 245 measures the dissolved oxygen concentration of the processing liquid LQ in the circulation piping 141 at a location in the circulation piping 141 that is closer to the processing tank 105 than to the outer tank 110. In other words, the measuring unit 245 measures the dissolved oxygen concentration of the processing liquid LQ in the circulation piping 141 at a location upstream of the valve 146, the control valve 145, the filter 144, the heater 143, and the pump 142, and adjacent to the outer bottom surface of the processing tank 105. The measuring unit 245 outputs information indicating the dissolved oxygen concentration of the processing liquid LQ to the control device 220.

[0054] The object to be measured by the measuring unit 245 is not particularly limited as long as it is the circulating processing liquid LQ. For example, the measuring unit 245 may measure the dissolved oxygen concentration of the processing liquid LQ stored in the processing tank 105. The measuring unit 245 is, for example, a dissolved oxygen meter. The dissolved oxygen meter measures the dissolved oxygen concentration of the processing liquid LQ by, for example, titration, diaphragm electrode method, or fluorescence method.

[0055] The control device 220 controls each component of the substrate processing apparatus 100. Specifically, the control device 220 controls the substrate holding unit 120, the processing liquid introduction unit 125, the drainage unit 170, the first gas adjustment unit 180, and the third gas supply unit 210.

[0056] Specifically, the control device 220 includes a control unit 221 and a storage unit 223. The control unit 221 includes a processor such as a CPU (Central Processing Unit). The storage unit 223 includes a storage device and stores data and computer programs. For example, the storage unit 223 includes a main storage device such as a semiconductor memory and an auxiliary storage device such as a semiconductor memory and a hard disk drive. The storage unit 223 may also include removable media such as an optical disc. The storage unit 223 is, for example, a non-temporary computer-readable storage medium. The control device 220 may also include an input device and a display device. The processor of the control unit 221 executes the computer programs stored in the storage device of the storage unit 223 to control each component of the substrate processing device 100.

[0057] The control unit 221 includes a first control unit A1, a second control unit A2, and a third control unit A3. Specifically, the processor of the control unit 221 executes a computer program stored in the memory device of the storage unit 223 to function as the first control unit A1, the second control unit A2, and the third control unit A3. The second control unit A2 corresponds to an example of the "gas control unit" of the present invention. The first to third control units A1 and A3 will be described later.

[0058] As explained above with reference to Figure 1, according to this embodiment, the first gas supply unit 200 supplies the first inert gas GA1 (bubble BB1) to the processing liquid LQ of the processing tank 105, thereby replacing the oxygen dissolved in the processing liquid LQ with the first inert gas GA1. Therefore, compared to the case where the first inert gas GA1 is not supplied, the dissolved oxygen concentration of the processing liquid LQ in the processing tank 105 can be reduced. As a result, the substrate W immersed in the processing liquid LQ can be effectively processed by the processing liquid LQ. In other words, by supplying the first inert gas GA1 (bubble BB1), the dissolved oxygen concentration of the processing liquid LQ is reduced, so the amount of processing of the substrate W by the processing liquid LQ can be increased compared to the case where the first inert gas GA1 is not supplied. In this embodiment, as an example, the processing of the substrate W by the processing liquid LQ is etching of the substrate W. In this case, the amount of processing of the substrate W by the processing liquid LQ is the amount of etching of the substrate W. Therefore, by supplying the first inert gas GA1 (bubble BB1), the amount of etching of the substrate W by the processing liquid LQ can be increased.

[0059] Furthermore, according to this embodiment, by supplying a first inert gas GA1 (bubble BB1) to the processing liquid LQ, the processing liquid LQ in contact with the surface of the substrate W can be effectively replaced with fresh processing liquid LQ. As a result, when a surface pattern including recesses is formed on the surface of the substrate W, the processing liquid LQ in the recesses can be effectively replaced with fresh processing liquid LQ by diffusion. Therefore, the walls within the recesses of the surface pattern can be effectively processed (etched) by the processing liquid LQ from shallow to deep positions. The recesses are, for example, recesses, holes, or trenches.

[0060] Furthermore, according to this embodiment, the processing liquid introduction section 125 introduces the processing liquid LQ into the processing tank 105 by laminar flow of the processing liquid LQ. Therefore, it is possible to suppress disturbance in the flow of bubbles BB1 supplied to the processing liquid LQ by the first gas supply section 200.

[0061] Furthermore, in this embodiment, since the third inert gas GA3 is supplied to the inside of the outer tank 110, it is possible to suppress the dissolution of oxygen into the processing liquid LQ inside the outer tank 110 through the upper opening 110a of the outer tank 110.

[0062] In the example shown in Figure 1, the third gas supply unit 210 is positioned above the processing liquid LQ in the outer tank 110 and discharges the third inert gas GA3 downward from each second discharge port H2. As a result, the third inert gas GA3 is discharged to the liquid surface of the processing liquid LQ in the outer tank 110 and also fills the outer tank 110. Specifically, the third gas supply pipe 25 is positioned above the processing liquid LQ in the outer tank 110 and discharges the third inert gas GA3 downward from each second discharge port H2. In this case, for example, the second discharge port H2 faces downward in the vertical direction D. That is, the second discharge port H2 is positioned at the bottom of the third gas supply pipe 25.

[0063] Next, we will explain the relationship between dissolved oxygen concentration and processing volume with reference to Figure 2. Figure 2 is a graph showing the relationship between the dissolved oxygen concentration of the processing solution LQ and the etching volume. The horizontal axis represents the dissolved oxygen concentration (ppm) in the processing solution LQ, and the vertical axis represents the etching volume (nm) of the substrate W.

[0064] Figure 2 shows an example where TMAH was used as the treatment solution LQ. The concentration of TMAH was 0.31%. The first inert gas GA1 was nitrogen. The third inert gas GA3 and mixed gas GA (described later) were not used. This example was simplified because its purpose was to verify the relationship between the dissolved oxygen concentration of the treatment solution LQ and the amount of etching.

[0065] A polysilicon film (polysilicon layer) was formed on the substrate W. Figure 2 shows the amount of etching of the polysilicon film when the substrate W is immersed in TMAH. The etching amount is the value obtained by subtracting the thickness of the polysilicon film after immersion from the thickness of the polysilicon film before immersion in TMAH. The etching amount is sometimes referred to as "etching amount of substrate W".

[0066] As shown in Figure 2, the lower the dissolved oxygen concentration in the processing solution LQ, the greater the etching amount (processing amount) of the substrate W. The etching amount (processing amount) was approximately directly proportional to the dissolved oxygen concentration. The proportionality constant was negative.

[0067] Next, with reference to Figure 3, the relationship between the flow rate of the first inert gas GA1 and the dissolved oxygen concentration will be explained. Figure 3 is a graph showing the relationship between the supply time of the first inert gas GA1 (bubble BB1) and the dissolved oxygen concentration of the treatment liquid LQ for each flow rate of the first inert gas GA1. The horizontal axis represents the supply time of the first inert gas GA1 (hours), and the vertical axis represents the dissolved oxygen concentration of the treatment liquid LQ (ppm).

[0068] Figure 3 shows an example where TMAH was used as the treatment solution LQ. The concentration of TMAH was 0.31%. The first inert gas GA1 was nitrogen. The third inert gas GA3 and mixed gas GA (described later) were not used. This example was simplified because its purpose was to verify the relationship between the flow rate of the inert gas and the dissolved oxygen concentration.

[0069] Plot g1 shows the dissolved oxygen concentration when the flow rate of the first inert gas GA1 is 10 liters / min. Plot g2 shows the dissolved oxygen concentration when the flow rate of the first inert gas GA1 is 20 liters / min. Plot g3 shows the dissolved oxygen concentration when the flow rate of the first inert gas GA1 is 30 liters / min. In this case, the flow rate of the first inert gas GA1 represents the flow rate supplied to one first gas supply pipe 21.

[0070] As can be seen from plots g1 to g3, the dissolved oxygen concentration in the treatment solution LQ became approximately constant after about one hour. Furthermore, when the dissolved oxygen concentration was approximately constant, the higher the flow rate of the first inert gas GA1, the lower the dissolved oxygen concentration in the treatment solution LQ became. In other words, when the dissolved oxygen concentration was approximately constant, the higher the amount of bubbles BB1 supplied to the treatment solution LQ, the lower the dissolved oxygen concentration in the treatment solution LQ became. This is because a higher flow rate of the first inert gas GA1 results in a greater supply of bubbles BB1 to the treatment solution LQ.

[0071] As can be understood from the embodiments in Figures 2 and 3, the higher the flow rate of the first inert gas GA1, the lower the dissolved oxygen concentration, and therefore the higher the flow rate of the first inert gas GA1, the greater the etching amount (processing amount) of the substrate W. In other words, the higher the number of bubbles BB1 supplied to the processing solution LQ, the lower the dissolved oxygen concentration, and therefore the higher the number of bubbles BB1, the greater the etching amount (processing amount) of the substrate W.

[0072] Next, the substrate holding section 120, the processing tank 105, and the outer tank 110 will be described with reference to Figure 4. Figures 4(a) and 4(b) are schematic perspective views of the substrate processing apparatus 100 before and after the substrate W is placed in the processing tank 105. In Figure 4, to avoid making the drawing excessively complex, the first lid 111, the second lid 112, the processing liquid LQ in the processing tank 105, and the processing liquid LQ in the outer tank 110, as shown in Figure 1, are omitted. Also, Figures 4(a) and 4(b) show an example in which one lot (for example, 25 sheets) of substrate W is processed in the processing tank 105.

[0073] As shown in Figure 4(a), the substrate holder 120 holds multiple substrates W along the first direction D10. Specifically, the substrate holder 120 holds multiple substrates W (one lot of substrates W) at intervals along the first direction D10. The multiple substrates W are arranged in a line along the first direction D10. In other words, the first direction D10 indicates the arrangement direction of the multiple substrates W. The first direction D10 is approximately parallel to the horizontal direction and approximately perpendicular to the vertical direction D. In addition, each of the multiple substrates W is approximately parallel to the second direction D20. The second direction D20 is approximately perpendicular to the first direction D10 and the vertical direction D, and approximately parallel to the horizontal direction.

[0074] In Figure 4(a), the substrate holder 120 is located above the processing tank 105. The substrate holder 120 descends along the vertical direction D while holding multiple substrates W. As a result, multiple substrates W are introduced into the processing tank 105. As shown in Figure 4(b), when the substrate holder 120 descends to the processing tank 105, the multiple substrates W are immersed in the processing liquid LQ in the processing tank 105.

[0075] The processing tank 105 includes a pair of side walls 105a and 105b, a first wall 105c, and a second wall 105d.

[0076] The pair of side walls 105a and 105b extend along the first direction D10. The pair of side walls 105a and 105b are spaced apart in the second direction D20. Each of the pair of side walls 105a and 105b has a substantially flat shape and is substantially parallel to the vertical direction D.

[0077] The first wall 105c and the second wall 105d extend along the second direction D20. The first wall 105c and the second wall 105d are spaced apart in the first direction D10. Each of the first wall 105c and the second wall 105d has a substantially flat shape and is substantially parallel to the vertical direction D. The first wall 105c and the second wall 105d are substantially perpendicular to the pair of side walls 105a and 105b.

[0078] The outer tank 110 surrounds the processing tank 105. Specifically, the outer tank 110 surrounds at least the upper circumferential surface of the processing tank 105. More specifically, the outer tank 110 has a first storage section 117a, a second storage section 117b, a third storage section 117c, and a fourth storage section 117d. The first to fourth storage sections 117a to 117d store the processing liquid LQ that overflows from the processing tank 105. The first to fourth storage sections 117a to 117d are in communication with each other. "Communication" includes not only direct communication but also indirect communication. For example, the first storage section 117a and the third storage section 117c are in direct communication. For example, the first storage section 117a and the second storage section 117b are indirectly connected via the third storage section 117c and the fourth storage section 117d.

[0079] The first storage section 117a extends along the first wall 105c. The first storage section 117a extends along the second direction D20. The first storage section 117a is located outside the first wall 105c and faces the first direction D10 relative to the first wall 105c. The first storage section 117a extends from the top to the bottom of the first wall 105c. The first storage section 117a is the storage section with the largest capacity among the first storage sections 117a to the fourth storage section 117d. The first storage section 117a corresponds to an example of the "storage section with the largest capacity" in the present invention.

[0080] The second storage section 117b extends along the second wall 105d. The second storage section 117b is located on the upper outer side of the second wall 105d and faces the second wall 105d in the first direction D10. The second storage section 117b extends along the second direction D20.

[0081] The third storage section 117c extends along the side wall 105a. The third storage section 117c extends along the first direction D10. The third storage section 117c is located on the upper outer side of the side wall 105a and faces the side wall 105a in the second direction D20. The third storage section 117c is located between the first storage section 117a and the second storage section 117b and connects the first storage section 117a and the second storage section 117b.

[0082] The fourth storage section 117d extends along the side wall 105b. The fourth storage section 117d extends along the first direction D10. The fourth storage section 117d is located on the upper outer side of the side wall 105b and faces the side wall 105b in the second direction D20. The fourth storage section 117d is located between the first storage section 117a and the second storage section 117b and connects the first storage section 117a and the second storage section 117b.

[0083] Next, the substrate processing apparatus 100 will be described with reference to Figures 5 to 7. Figure 5 is a schematic plan view of the substrate processing apparatus 100. Figure 6 is a cross-sectional view along the line VI-VI in Figure 5. Figure 7 is a cross-sectional view along the line VII-VII in Figure 5. Note that Figures 5 to 7 show the apparatus with the first cover 111 and the second cover 112 (Figure 1) removed. Also, in Figures 5 to 7, the substrate holding section 120 (Figure 1) is omitted, and no substrate W is placed in the processing tank 105. These points also apply to Figures 11 to 13, which will be described later.

[0084] As shown in Figure 5, the substrate processing apparatus 100 further comprises a second gas supply unit 230, a second gas adjustment unit 240, and piping 74, 86, and 96. The second gas adjustment unit 240 corresponds to an example of the "gas adjustment unit" of the present invention.

[0085] Pipes 86 and 96 merge at a confluence point 79 and are connected to pipe 74 at the confluence point 79. Pipe 86 is connected to a second inert gas supply source K2. The second inert gas supply source K2 stores a second inert gas GA2. The second inert gas GA2 is, for example, nitrogen or argon. In this embodiment, the second inert gas GA2 is the same as the first inert gas GA1. The second inert gas GA2 is supplied to pipe 86 from the second inert gas supply source K2. Pipe 96 is also connected to an air supply source K4. Air AR is supplied to pipe 96 from the air supply source K4.

[0086] At the confluence point 79, the second inert gas GA2 and air AR are mixed, and the mixed gas GA is supplied to the piping 74. In other words, the mixed gas GA is a gas obtained by mixing the second inert gas GA2 and air AR. The mixed gas GA corresponds to an example of the "gas" of the present invention. The mixed gas GA is supplied from the piping 74 to the second gas supply unit 230.

[0087] As shown in Figures 5 to 7, the second gas supply unit 230 supplies mixed gas GA to the processing liquid LQ stored in the outer tank 110. Specifically, the second gas supply unit 230 supplies bubbles BB2 of the mixed gas GA to the processing liquid LQ stored in the outer tank 110.

[0088] The second gas adjustment unit 240 adjusts the flow rate of the mixed gas GA supplied to the second gas supply unit 230. In other words, the second gas adjustment unit 240 adjusts the flow rate of the mixed gas GA supplied to the second gas supply unit 230, thereby adjusting the flow rate of the mixed gas GA supplied by the second gas supply unit 230 to the processing liquid LQ. The flow rate of the mixed gas GA represents the flow rate per unit time.

[0089] In this embodiment, adjusting the flow rate of the mixed gas GA means adjusting the ratio RA of the flow rate of the second inert gas GA2 and the flow rate of air AR. For example, the second gas adjustment unit 240 adjusts the ratio RA while increasing the flow rate of the mixed gas GA. Or, for example, the second gas adjustment unit 240 adjusts the ratio RA while decreasing the flow rate of the mixed gas GA. Or, for example, the second gas adjustment unit 240 adjusts the ratio RA while keeping the flow rate of the mixed gas GA constant. Note that the flow rate of the second inert gas GA2 is the flow rate per unit time. The flow rate of air AR is the flow rate per unit time.

[0090] The second control unit A2 controls the second gas adjustment unit 240. Specifically, the second control unit A2 acquires information indicating the dissolved oxygen concentration of the processing liquid LQ from the measurement unit 245 (Figure 1). Then, while the flow rate of the first inert gas GA1 (Figure 1) is kept constant, the second control unit A2 controls the second gas adjustment unit 240 based on the dissolved oxygen concentration of the processing liquid LQ, thereby adjusting the flow rate of the mixed gas GA supplied to the second gas supply unit 230 (i.e., the mixed gas GA supplied from the second gas supply unit 230 to the processing liquid LQ) and adjusting the dissolved oxygen concentration of the processing liquid LQ stored in the processing tank 105.

[0091] In other words, while supplying the mixed gas GA to the processing liquid LQ of the outer tank 110, the flow rate of the first inert gas GA1 (Figure 1) supplied to the processing liquid LQ of the processing tank 105 is kept constant. This suppresses the first inert gas GA1 from affecting the uniformity of processing within the plane of the substrate W and / or the uniformity of processing between multiple substrates W. In addition, by adjusting the flow rate of the mixed gas GA supplied to the processing liquid LQ of the outer tank 110, the dissolved oxygen concentration of the processing liquid LQ can be kept within the target concentration range, and consequently, the etching amount or etching rate of the substrate W can be kept within the target range.

[0092] Before explaining this point in detail, let's explain the dissolved oxygen concentration of the processing liquid LQ. For example, when introducing deionized water (DIW) contained in the processing liquid LQ from the factory's power supply system, the dissolved oxygen concentration of the deionized water may differ depending on the factory environment (e.g., the location of the factory, the location of the substrate processing device 100 within the factory, and the length of the piping that supplies the deionized water). Therefore, the dissolved oxygen concentration of the processing liquid LQ containing deionized water may also differ depending on the factory environment. In particular, when the deionized water content in the processing liquid LQ is high, the dissolved oxygen concentration of the deionized water has a significant impact on the dissolved oxygen concentration of the processing liquid LQ.

[0093] As shown in Figure 2, the amount of etching and the etching rate differ depending on the dissolved oxygen concentration of the processing solution LQ. Therefore, when it is required that the amount of etching or etching rate of the substrate W be within a target range, depending on the factory environment, it may occur that the amount of etching or etching rate of the substrate W does not fall within the target range. This occurs when the amount of etching or etching rate of the substrate W is either below the target range or exceeds the target range.

[0094] Therefore, for example, by adjusting the flow rate of the first inert gas GA1 supplied to the processing liquid LQ in the processing tank 105, the dissolved oxygen concentration of the processing liquid LQ can be adjusted to a target concentration range, thereby bringing the etching amount or etching rate of the substrate W within the target range. The target concentration range indicates the range of dissolved oxygen concentration required to bring the etching amount or etching rate of the substrate W within the target range. The target concentration range is determined, for example, experimentally and / or empirically.

[0095] However, the inventors of the present invention have found that even if the dissolved oxygen concentration of the processing liquid LQ is brought within the target concentration range by adjusting the flow rate of the first inert gas GA1, adjusting the flow rate of the first inert gas GA1 may affect the uniformity of processing within the plane of the substrate W and / or the uniformity of processing between multiple substrates W. In other words, the inventors of the present invention have found that if the flow rate of the first inert gas GA1 supplied to the processing liquid LQ of the processing tank 105 is different, the uniformity of processing within the plane of the substrate W may differ, or the uniformity of processing between multiple substrates W may differ.

[0096] This also applies when the substrate processing apparatus 100 is equipped with multiple processing tanks 105, and when multiple substrate processing apparatuses 100 are installed in different locations, the same applies between the multiple processing tanks 105. For example, if the flow rate of the first inert gas GA1 in a processing tank 105 of the substrate processing apparatus 100 differs from the flow rate of the first inert gas GA1 in another processing tank 105 of the same substrate processing apparatus 100, the uniformity of processing within the plane of the substrate W and / or the uniformity of processing between multiple substrates W may differ between the multiple processing tanks 105. For example, if the flow rate of the first inert gas GA1 in a processing tank 105 of the substrate processing apparatus 100 differs from the flow rate of the first inert gas GA1 in a processing tank 105 of another substrate processing apparatus 100, the uniformity of processing within the plane of the substrate W and / or the uniformity of processing between multiple substrates W may differ between multiple substrate processing apparatuses 100 installed in different locations.

[0097] Therefore, in this embodiment, the substrate processing apparatus 100 supplies the first inert gas GA1 to the processing liquid LQ stored in the processing tank 105 while maintaining a constant flow rate of the first inert gas GA1. Then, while the flow rate of the first inert gas GA1 is maintained at a constant level, the substrate processing apparatus 100 adjusts the dissolved oxygen concentration of the processing liquid LQ stored in the processing tank 105 by adjusting the flow rate of the mixed gas GA supplied to the second gas supply unit 230 (i.e., the mixed gas GA supplied from the second gas supply unit 230 to the processing liquid LQ) based on the dissolved oxygen concentration of the processing liquid LQ. As a result, according to this embodiment, it is possible to keep the dissolved oxygen concentration of the processing liquid LQ within the target concentration range while suppressing the first inert gas GA1 supplied to the processing liquid LQ in the processing tank 105 from affecting the uniformity of processing within the plane of the substrate W and / or the uniformity of processing between multiple substrates W.

[0098] Furthermore, in this embodiment, when the substrate processing apparatus 100 is equipped with a plurality of processing tanks 105, the etching amount or etching rate can be kept within the target range while ensuring uniformity of processing within the plane of the substrate W and / or uniformity of processing between multiple substrates W, among the plurality of processing tanks 105. Moreover, when multiple substrate processing apparatuses 100 are installed in different locations, the etching amount or etching rate can be kept within the target range while ensuring uniformity of processing within the plane of the substrate W and / or uniformity of processing between multiple substrates W, among different substrate processing apparatuses 100.

[0099] The treatment liquid LQ circulates between the outer tank 110 and the treatment tank 105 via the treatment liquid introduction section 125 (Figure 1). Therefore, the treatment liquid LQ, whose dissolved oxygen concentration has been adjusted in the outer tank 110, is introduced into the treatment tank 105. As a result, the dissolved oxygen concentration of the treatment liquid LQ in the treatment tank 105 is adjusted by adjusting the dissolved oxygen concentration of the treatment liquid LQ in the outer tank 110.

[0100] The details of the second gas supply unit 230 and the second gas adjustment unit 240 will now be explained with reference to Figures 5 to 7.

[0101] The second gas supply unit 230 is located inside the outer tank 110. The second gas supply unit 230 includes at least one second gas supply pipe 70. In this embodiment, the second gas supply unit 230 includes one second gas supply pipe 70. The second gas supply pipe 70 is located on the bottom side of the outer tank 110. The second gas supply pipe 70 is immersed in the processing liquid LQ. The second gas supply pipe 70 extends along the second direction D20.

[0102] The second gas supply pipe 70 has a plurality of second discharge holes H2. The plurality of second discharge holes H2 are provided at the top of the second gas supply pipe 70. In this case, for example, the second discharge holes H2 face upward in the vertical direction D. The plurality of second discharge holes H2 are arranged in a substantially straight line with spacing between them in the second direction D20.

[0103] The second gas supply pipe 70 supplies bubbles BB2 of the mixed gas GA to the processing liquid LQ from each of the multiple second discharge holes H2 by discharging the mixed gas GA from each of the second discharge holes H2.

[0104] The second gas supply pipe 70 is, for example, a bubbler pipe. The material of the second gas supply pipe 70 is, for example, quartz or resin. The resin is, for example, a corrosion-resistant resin such as PEEK, PFA, and PTFE. The diameter of the second gas supply pipe 70 is not particularly limited, but for example, it is about 6.0 mm. The diameter of the second discharge hole H2 is not particularly limited, but for example, it is about 0.2 mm. Preferably, the diameter of the second discharge hole H2 is smaller than the diameter of the first discharge hole H1 (Figure 1). The reason for this preference is that the smaller the diameter of the second discharge hole H2, the smaller the bubbles BB2 become. In this case, for example, the diameter of the second discharge hole H2 is about 0.1 mm or more and about 0.15 mm or less.

[0105] The second gas supply pipe 70 is located in the first storage section 117a, which has the largest capacity among the first to fourth storage sections 117a to 117d. Specifically, the second gas supply pipe 70 is located at the bottom of the first storage section 117a. The second gas supply pipe 70 supplies mixed gas GA to the processing liquid LQ stored in the first storage section 117a. Specifically, the second gas supply pipe 70 supplies bubbles BB2 of the mixed gas GA to the processing liquid LQ stored in the first storage section 117a from each second discharge hole H2. Therefore, the dissolved oxygen concentration of the processing liquid LQ stored in the first storage section 117a, which has the largest capacity, is concentrated and regulated by the mixed gas GA (bubbles BB2). The processing liquid LQ with the regulated dissolved oxygen concentration is then introduced into the processing tank 105. As a result, according to this embodiment, the dissolved oxygen concentration of the treatment liquid LQ in the treatment tank 105 can be adjusted to the target concentration range in a shorter time.

[0106] Furthermore, the circulation pipe 141 is connected to the bottom of the first storage section 117a. Specifically, the upstream end of the circulation pipe 141 is connected to the treatment liquid supply port 147 provided at the bottom of the first storage section 117a. Therefore, the treatment liquid LQ from the outer tank 110 is supplied to the circulation pipe 141 through the treatment liquid supply port 147. On the other hand, the second gas supply pipe 70 supplies mixed gas GA (bubbles BB2) from the bottom side of the first storage section 117a towards the liquid surface of the treatment liquid LQ through each second discharge port H2. In other words, the second gas supply pipe 70 supplies mixed gas GA (bubbles BB2) from the bottom side of the first storage section 117a towards the vertical direction D upward through each second discharge port H2. Therefore, according to this embodiment, it is possible to suppress bubbles BB2 from entering the treatment liquid supply port 147. As a result, the decrease in the number of bubbles BB2 in contact with the treatment liquid LQ in the first storage section 117a is suppressed, and the dissolved oxygen concentration of the treatment liquid LQ in the first storage section 117a can be effectively adjusted by the bubbles BB2.

[0107] Furthermore, as shown in Figure 6, the second gas supply pipe 70 is positioned approximately in the center of the first direction D10 at the bottom of the first storage section 117a. Therefore, according to this embodiment, it is possible to suppress the contact of bubbles BB2 with the first wall 105c and the wall surface 117e of the first storage section 117a. As a result, bubbles BB2 come into contact with the processing liquid LQ more frequently, and the dissolved oxygen concentration of the processing liquid LQ can be effectively adjusted by bubbles BB2.

[0108] Furthermore, the outer tank 110 has a drain port 250. The drain port 250 is located at the top of the outer tank 110. Specifically, the drain port 250 is located at the top of the first storage section 117a. The substrate processing apparatus 100 also includes piping 251. The piping 251 is connected to the drain port 250. The processing liquid LQ that reaches the drain port 250 is discharged to the outside of the outer tank 110 from the drain port 250 and the piping 251. Therefore, overflow of the processing liquid LQ from the outer tank 110 can be suppressed. In particular, in this embodiment, since a large number of bubbles BB2 are supplied to the processing liquid LQ of the first storage section 117a, the processing liquid LQ may be more likely to overflow from the outer tank 110 compared to when bubbles BB2 are not supplied. Therefore, in this embodiment, drainage through the drain port 250 and the piping 251 is particularly effective in suppressing overflow of the processing liquid LQ from the outer tank 110.

[0109] Furthermore, as shown in Figure 7, the second gas supply unit 230 further includes a pipe 71. The pipe 71 extends along the vertical direction D. One end (lower end) of the pipe 71 is connected to one end of the second gas supply pipe 70 in the second direction D20. The other end of the second gas supply pipe 70 in the second direction D20 is closed. The other end (upper end) of the pipe 71 is connected to the piping 74. Therefore, the mixed gas GA supplied from the piping 74 is supplied to the second gas supply pipe 70 through the pipe 71.

[0110] In particular, in this embodiment, the second gas adjustment unit 240 shown in Figure 5 adjusts the ratio RA of the flow rate of the second inert gas GA2 to the flow rate of air AR in the mixed gas GA supplied to the second gas supply unit 230, thereby adjusting the ratio RA of the flow rate of the second inert gas GA2 to the flow rate of air AR in the mixed gas GA supplied to the second gas supply unit 230 to the processed liquid LQ. In other words, the second gas adjustment unit 240 adjusts the dissolved oxygen concentration of the processed liquid LQ in the processed tank 105 by adjusting the ratio RA of the flow rate of the second inert gas GA2 to the flow rate of air AR in the mixed gas GA. That is, by adjusting the ratio RA, the dissolved oxygen concentration of the processed liquid LQ in the outer tank 110 is adjusted, and the dissolved oxygen concentration of the processed liquid LQ in the processed tank 105 is adjusted by the circulation of the processed liquid LQ. Therefore, according to this embodiment, the dissolved oxygen concentration of the processed liquid LQ in the processed tank 105 can be easily adjusted by the simple operation of adjusting the ratio RA.

[0111] Specifically, if the dissolved oxygen concentration of the processing liquid LQ obtained from the measurement unit 245 is not within the target concentration range, the second control unit A2 controls the second gas adjustment unit 240 based on the dissolved oxygen concentration of the processing liquid LQ to adjust the ratio RA of the flow rate of the second inert gas GA2 and the flow rate of air AR in the mixed gas GA so that the dissolved oxygen concentration of the processing liquid LQ is within the target concentration range. In other words, the second control unit A2 adjusts the ratio RA by feedback control to keep the dissolved oxygen concentration of the processing liquid LQ within the target concentration range. If the dissolved oxygen concentration of the processing liquid LQ obtained from the measurement unit 245 is within the target concentration range, the second control unit A2 and the second gas adjustment unit 240 maintain the ratio RA.

[0112] More specifically, if the dissolved oxygen concentration of the processing liquid LQ obtained from the measurement unit 245 exceeds the target concentration range, the second control unit A2 controls the second gas adjustment unit 240 to increase the proportion of the flow rate of the second inert gas GA2 in the mixed gas GA so that the dissolved oxygen concentration falls within the target concentration range. As a result, the second gas adjustment unit 240 increases the proportion of the flow rate of the second inert gas GA2 in the mixed gas GA to a level greater than the proportion of the flow rate of the second inert gas GA2 when the dissolved oxygen concentration is measured by the measurement unit 245 (the current proportion of the flow rate of the second inert gas GA2). Therefore, the dissolved oxygen concentration of the processing liquid LQ in the outer tank 110 decreases, and the dissolved oxygen concentration of the processing liquid LQ falls within the target concentration range. Note that when the dissolved oxygen concentration of the processing liquid LQ exceeds the target concentration range, it means that the dissolved oxygen concentration exceeds the upper limit of the target concentration range.

[0113] From the graph shown in Figure 3, it can be inferred that increasing the proportion of the second inert gas GA2 in the mixed gas GA reduces the dissolved oxygen concentration of the treatment liquid LQ.

[0114] Furthermore, if the dissolved oxygen concentration of the processing liquid LQ obtained from the measurement unit 245 exceeds the target concentration range, the second control unit A2 may control the second gas adjustment unit 240 to reduce the proportion of air AR flow rate in the mixed gas GA so that the dissolved oxygen concentration falls within the target concentration range. In this case, the second gas adjustment unit 240 reduces the proportion of air AR flow rate in the mixed gas GA to a level lower than the proportion of air AR flow rate when the dissolved oxygen concentration is measured by the measurement unit 245 (the current proportion of air AR flow rate). In this case, the proportion of the second inert gas GA2 flow rate in the mixed gas GA increases.

[0115] Here, reducing the proportion of air AR in the gas mixture GA is equivalent to reducing the proportion of oxygen in the gas mixture GA. This is because air AR contains approximately 20% oxygen. Therefore, by reducing the proportion of air AR in the gas mixture GA, the proportion of oxygen in the gas mixture GA decreases, and the dissolved oxygen concentration in the treatment liquid LQ decreases.

[0116] Meanwhile, if the dissolved oxygen concentration of the processing liquid LQ obtained from the measurement unit 245 is below the target concentration range, the second control unit A2 controls the second gas adjustment unit 240 to reduce the proportion of the flow rate of the second inert gas GA2 in the mixed gas GA so that the dissolved oxygen concentration falls within the target concentration range. As a result, the second gas adjustment unit 240 reduces the proportion of the flow rate of the second inert gas GA2 in the mixed gas GA to less than the proportion of the flow rate of the second inert gas GA2 when the dissolved oxygen concentration is measured by the measurement unit 245 (the current proportion of the flow rate of the second inert gas GA2). Therefore, the dissolved oxygen concentration of the processing liquid LQ in the outer tank 110 increases, and the dissolved oxygen concentration of the processing liquid LQ falls within the target concentration range. Note that if the dissolved oxygen concentration of the processing liquid LQ is below the target concentration range, it means that the dissolved oxygen concentration is below the lower limit of the target concentration range.

[0117] From the graph shown in Figure 3, it can be inferred that reducing the proportion of the flow rate of the second inert gas GA2 in the mixed gas GA increases the dissolved oxygen concentration of the treatment liquid LQ.

[0118] Furthermore, if the dissolved oxygen concentration of the processing liquid LQ obtained from the measurement unit 245 falls below the target concentration range, the second control unit A2 may control the second gas adjustment unit 240 to increase the proportion of air AR flow rate in the mixed gas GA so that the dissolved oxygen concentration falls within the target concentration range. In this case, the second gas adjustment unit 240 increases the proportion of air AR flow rate in the mixed gas GA to a level greater than the proportion of air AR flow rate when the measurement unit 245 measures the dissolved oxygen concentration (the current proportion of air AR flow rate).

[0119] Here, since air AR contains approximately 20% oxygen, increasing the proportion of air AR in the mixed gas GA increases the proportion of oxygen in the mixed gas GA. As a result, the dissolved oxygen concentration in the treatment liquid LQ increases.

[0120] The details of the second gas control unit 240 will now be explained with reference to Figure 5. The second gas control unit 240 includes a check valve 72, a filter 73, an inert gas control mechanism 80, and an air control mechanism 90. The filter 73 and the check valve 72 are arranged in this order from upstream to downstream of the piping 74. The filter 73 removes foreign matter from the mixed gas GA flowing through the piping 74. The check valve 72 prevents backflow of the mixed gas GA.

[0121] The inert gas adjustment mechanism 80 is located in the piping 86. The inert gas adjustment mechanism 80 adjusts the flow rate and pressure of the second inert gas GA2 supplied from the second inert gas supply source K2 to the piping 86.

[0122] Specifically, the inert gas control mechanism 80 includes a valve 81, a control valve 82, a flow meter 83, a pressure gauge 84, and a regulator 85. The regulator 85, pressure gauge 84, flow meter 83, control valve 82, and valve 81 are arranged in this order in the piping 86 from upstream to downstream.

[0123] Regulator 85 adjusts the pressure of the second inert gas GA2 in the piping 86. Regulator 85 is, for example, an electro-pneumatic regulator. Pressure gauge 84 measures the pressure of the second inert gas GA2 in the piping 86. Flow meter 83 measures the flow rate of the second inert gas GA2 flowing through the piping 86. Control valve 82 adjusts the flow rate of the second inert gas GA2 flowing through the piping 86 by adjusting the opening of the control valve 82, thereby adjusting the proportion of the flow rate of the second inert gas GA2 in the mixed gas GA. For example, a mass flow controller may be provided instead of control valve 82 and flow meter 83. Valve 81 opens and closes the piping 86. That is, valve 81 switches the supply of the second inert gas GA2 from piping 86 to piping 74 and the second gas supply pipe 70 on and off.

[0124] The air conditioning mechanism 90 also includes a valve 91, a control valve 92, a flow meter 93, a pressure gauge 94, and a regulator 95. The regulator 95, pressure gauge 94, flow meter 93, control valve 92, and valve 91 are arranged in this order in the piping 96 from upstream to downstream.

[0125] The regulator 95 adjusts the pressure of the air AR in the piping 96. The regulator 95 is, for example, an electro-pneumatic regulator. The pressure gauge 94 measures the pressure of the air AR in the piping 96. The flow meter 93 measures the flow rate of the air AR flowing through the piping 96. The control valve 92 adjusts the flow rate of the air AR flowing through the piping 96 by adjusting the opening of the control valve 92, thereby adjusting the proportion of the air AR flow rate in the mixed gas GA. For example, a mass flow controller may be provided instead of the control valve 92 and the flow meter 93. The valve 91 opens and closes the piping 96. In other words, the valve 91 switches the supply of air AR from the piping 96 to the piping 74 and the second gas supply pipe 70 on and off.

[0126] The second control unit A2 adjusts the flow rate of the second inert gas GA2 flowing through the pipe 86 by controlling the inert gas adjustment mechanism 80 while monitoring the flow rate of the second inert gas GA2 measured by the flow meter 83. On the other hand, the second control unit A2 adjusts the flow rate of air AR flowing through the pipe 96 by controlling the air adjustment mechanism 90 while monitoring the flow rate of air AR measured by the flow meter 93.

[0127] For example, if the dissolved oxygen concentration of the processing liquid LQ obtained from the measurement unit 245 exceeds the target concentration range, the second control unit A2 controls the inert gas adjustment mechanism 80 (specifically the adjustment valve 82) to increase the flow rate of the second inert gas GA2, while maintaining the flow rate of air AR. In other words, if the dissolved oxygen concentration of the processing liquid LQ exceeds the target concentration range, the second control unit A2 controls the inert gas adjustment mechanism 80 (specifically the adjustment valve 82) to increase the flow rate of the second inert gas GA2, thereby increasing the proportion of the flow rate of the second inert gas GA2 in the mixed gas GA and bringing the dissolved oxygen concentration of the processing liquid LQ within the target concentration range.

[0128] For example, the second control unit A2 may control the air adjustment mechanism 90 (specifically the adjustment valve 92) to reduce the flow rate of air AR when the dissolved oxygen concentration of the processing liquid LQ obtained from the measurement unit 245 exceeds the target concentration range, while maintaining the flow rate of the second inert gas GA2. In other words, the second control unit A2 may reduce the proportion of the air AR flow rate in the mixed gas GA by controlling the air adjustment mechanism 90 (specifically the adjustment valve 92) to reduce the flow rate of air AR when the dissolved oxygen concentration of the processing liquid LQ exceeds the target concentration range, thereby keeping the dissolved oxygen concentration of the processing liquid LQ within the target concentration range.

[0129] On the other hand, for example, if the dissolved oxygen concentration of the processing liquid LQ obtained from the measurement unit 245 is below the target concentration range, the second control unit A2 controls the inert gas adjustment mechanism 80 (specifically the adjustment valve 82) to reduce the flow rate of the second inert gas GA2, while maintaining the flow rate of air AR. In other words, if the dissolved oxygen concentration of the processing liquid LQ is below the target concentration range, the second control unit A2 controls the inert gas adjustment mechanism 80 (specifically the adjustment valve 82) to reduce the flow rate of the second inert gas GA2, thereby reducing the proportion of the flow rate of the second inert gas GA2 in the mixed gas GA and bringing the dissolved oxygen concentration of the processing liquid LQ within the target concentration range.

[0130] For example, if the dissolved oxygen concentration of the processing liquid LQ obtained from the measurement unit 245 falls below the target concentration range, the second control unit A2 may control the air adjustment mechanism 90 (specifically the adjustment valve 92) to increase the flow rate of air AR while maintaining the flow rate of the second inert gas GA2. In other words, if the dissolved oxygen concentration of the processing liquid LQ falls below the target concentration range, the second control unit A2 may control the air adjustment mechanism 90 (specifically the adjustment valve 92) to increase the flow rate of air AR, thereby increasing the proportion of the air AR flow rate in the mixed gas GA and bringing the dissolved oxygen concentration of the processing liquid LQ within the target concentration range.

[0131] Next, the third gas supply unit 210 (Figure 1) will be described with reference to Figures 5 and 6. As shown in Figure 5, the third gas supply unit 210 includes a third gas supply pipe 25 and a valve 26. The third gas supply pipe 25 is located inside the outer tank 110. The third gas supply pipe 25 surrounds the processing tank 105. Specifically, the third gas supply pipe 25 includes a first piping section 25a, a second piping section 25b, a third piping section 25c, a fourth piping section 25d, a fifth piping section 25e, and a sixth piping section 25f.

[0132] The first piping section 25a is located in the upper region inside the first storage section 117a. The first piping section 25a extends along the first direction D10. The first piping section 25a extends from the inside to the outside of the outer tank 110.

[0133] The second piping section 25b is located in the upper region inside the first storage section 117a. The second piping section 25b bends from the downstream end of the first piping section 25a and extends along the first wall 105c. The second piping section 25b extends along the second direction D20.

[0134] The third piping section 25c is located in the upper region inside the third storage section 117c. The third piping section 25c bends from the downstream end of the second piping section 25b and extends along the side wall 105a. The third piping section 25c extends along the first direction D10.

[0135] The fourth piping section 25d is located in the upper region inside the second storage section 117b. The fourth piping section 25d bends from the downstream end of the third piping section 25c and extends along the second wall 105d. The fourth piping section 25d extends along the second direction D20.

[0136] The fifth piping section 25e is located in the upper region inside the fourth storage section 117d. The fifth piping section 25e bends from the downstream end of the fourth piping section 25d and extends along the side wall 105b. The fifth piping section 25e extends along the first direction D10.

[0137] The sixth piping section 25f is located in the upper region inside the first storage section 117a. The sixth piping section 25f bends from the downstream end of the fifth piping section 25e and extends along the first wall 105c. The sixth piping section 25f extends along the second direction D20. The downstream end of the sixth piping section 25f is closed.

[0138] Each of the first piping sections 25a to the sixth piping section 25f is provided with multiple third discharge holes H3 (Figure 1). Therefore, the dissolution of oxygen into the processing liquid LQ can be suppressed in any of the first storage sections 117a to the fourth storage section 117d.

[0139] The substrate processing apparatus 100 further includes piping 185. Piping 185 connects the third gas supply pipe 25 (specifically the first piping section 25a) and the third inert gas supply source K3 via a valve 26. The third inert gas supply source K3 stores the third inert gas GA3.

[0140] Valve 26 is positioned in piping 185 outside the processing tank 105 and the outer tank 110. By opening the flow path of piping 185, valve 26 supplies the third inert gas GA3 from the third inert gas supply source K3 to the third gas supply pipe 25. Conversely, by closing the flow path of piping 185, valve 26 stops the supply of the third inert gas GA3 from the third inert gas supply source K3 to the third gas supply pipe 25.

[0141] As shown in Figure 6, in the third gas supply pipe 25, the multiple third discharge holes H3 are arranged in a nearly straight line with spacing between them in the first direction D10. The multiple third discharge holes H3 open downward in the vertical direction D and are opposite the liquid surface of the processing liquid LQ in the vertical direction D. The third gas supply pipe 25 discharges the third inert gas GA3 from the multiple third discharge holes H3 toward the liquid surface of the processing liquid LQ in the outer tank 110.

[0142] As shown in Figures 5 and 6, the third control unit A3 controls the valve 26 to supply the third inert gas GA3 to the third gas supply pipe 25. As a result, the valve 26 opens the flow path of the piping 185, supplying the third inert gas GA3 to the third gas supply pipe 25. Thus, the third gas supply pipe 25 discharges the third inert gas GA3 into the outer tank 110 from each of the third discharge holes H3.

[0143] Next, the first gas supply unit 200 will be described with reference to Figure 8. Figure 8 is a schematic plan view showing the first gas supply unit 200. As shown in Figure 8, the multiple first gas supply pipes 21 are arranged substantially parallel to each other and spaced apart in a plan view. In the example of Figure 8, the multiple first gas supply pipes 21 are arranged symmetrically with respect to a virtual center line CL. The virtual center line CL passes through the center of each substrate W and extends along the first direction D10.

[0144] Specifically, the multiple first gas supply pipes 21 are arranged in the processing tank 105 substantially parallel to each other and spaced apart in the second direction D20. The first gas supply pipes 21 extend along the first direction D10. In each of the multiple first gas supply pipes 21, the multiple first discharge holes H1 are arranged substantially in a straight line spaced apart in the first direction D10.

[0145] Each of the multiple gas flow control mechanisms 182 includes a valve 41, a filter 42, a flow meter 43, and a control valve 44. The valve 41, filter 42, flow meter 43, and control valve 44 are arranged in the piping 181 in this order from downstream to upstream.

[0146] The control valve 44 can adjust the flow rate of the first inert gas GA1 supplied to the piping 181 by adjusting the opening of the control valve 44, thereby adjusting the flow rate of the first inert gas GA1 supplied to the first gas supply pipe 21. The flow meter 43 measures the flow rate of the first inert gas GA1 flowing through the piping 181. The control valve 44 adjusts the flow rate of the first inert gas GA1 based on the measurement results of the flow meter 43. For example, a mass flow controller may be provided instead of the control valve 44 and the flow meter 43.

[0147] In this embodiment, the control valve 44 sets the flow rate of the first inert gas GA1 supplied to the piping 181 to a constant level when the control valve 44 is set to a certain opening degree, thereby maintaining a constant flow rate (individual flow rate) of the first inert gas GA1 supplied to the first gas supply pipe 21. In other words, the control valve 44 sets the flow rate (individual flow rate) of the first inert gas GA1 supplied to the first gas supply pipe 21 to a target individual flow rate. Note that the target individual flow rates may be the same or different for multiple first gas supply pipes 21.

[0148] Specifically, the first control unit A1 controls the gas flow rate adjustment mechanism 182 (specifically the adjustment valve 44) so ​​that the flow rate (individual flow rate) of the first inert gas GA1 supplied to the first gas supply pipe 21 is kept constant. In other words, the first control unit A1 controls the gas flow rate adjustment mechanism 182 (specifically the adjustment valve 44) so ​​that the flow rate (individual flow rate) of the first inert gas GA1 supplied to the first gas supply pipe 21 is set to the target individual flow rate.

[0149] Since the flow rate of the first inert gas GA1 supplied to each of the multiple first gas supply pipes 21 (individual flow rates) is kept constant, the total flow rate of the first inert gas GA1 supplied to the multiple first gas supply pipes 21 is also kept constant. In other words, the total flow rate of the first inert gas GA1 supplied to the multiple first gas supply pipes 21 is set to the target total flow rate.

[0150] The filter 42 removes foreign matter from the first inert gas GA1 flowing through the piping 181. The valve 41 opens and closes the piping 181. In other words, the valve 41 switches the supply of the first inert gas GA1 from the piping 181 to the first gas supply pipe 21 on and off. The opening and closing of the valve 41 is controlled by the first control unit A1.

[0151] Next, the introduction section 130 will be described with reference to Figure 9. Figure 9 is a schematic rear view showing the introduction section 130. As shown in Figure 9, the introduction section 130 includes a plurality of discharge sections 131 and a plurality of dispersion plates 132. In the example of Figure 9, the introduction section 130 includes two discharge sections 131 and two dispersion plates 132. The plurality of discharge sections 131 are arranged at intervals in the first direction D10. The plurality of dispersion plates 132 are arranged at intervals in the first direction D10. Each of the plurality of dispersion plates 132 corresponds to one of the plurality of discharge sections 131. The plurality of dispersion plates 132 are located below the plate 31. In the example of Figure 9, the dispersion plates 132 have a substantially disc shape. Each of the plurality of discharge sections 131 is located below the plurality of dispersion plates 132.

[0152] The discharge section 131 and the dispersion plate 132 are positioned in a rear view corresponding to the central region 31a of the plate 31 in the second direction D20. The central region 31a extends along the first direction D10.

[0153] The circulation piping 141 (Figure 1) includes piping 133. Piping 133 extends from one end to the other in the first direction D10 of the plate 31. Piping 133 extends along the first direction D10. Piping 133 faces the back surface of the plate 31. In other words, piping 133 is located below the plate 31. Specifically, piping 133 is located below the distribution plate 132.

[0154] The discharge section 131 is connected to the upper surface of the piping 133. The discharge section 131 and the piping 133 are in communication. The discharge section 131 protrudes vertically upward from the piping 133 toward the dispersion plate 132. The piping 133 is supplied with the treatment liquid LQ from the circulation section 140 (Figure 1). As a result, the discharge section 131 discharges the treatment liquid LQ toward the dispersion plate 132. Therefore, the pressure of the treatment liquid LQ is dispersed, and the treatment liquid LQ spreads horizontally. The treatment liquid LQ then rises from multiple treatment liquid holes P, forming a laminar flow.

[0155] Next, the substrate processing method according to this embodiment will be described with reference to Figures 1, 5, 6, and 10. The substrate processing method is performed in a substrate processing apparatus 100 in which processing liquid LQ is circulated between a processing tank 105 and an outer tank 110. Figure 10 is a flowchart of an example of the substrate processing method according to this embodiment. As shown in Figure 10, the substrate processing method includes steps S1 to S10. As an example, before the start of step S1, all valves 41 (Figure 8) and valves 81, 91, and 26 (Figure 5) are closed.

[0156] As shown in Figures 1 and 10, first, in step S1, the substrate processing apparatus 100 circulates the processing liquid LQ between the outer tank 110 and the processing tank 105. Specifically, the control unit 221 controls the processing liquid introduction unit 125 to introduce the processing liquid LQ from the outer tank 110 to the processing tank 105. As a result, the processing liquid introduction unit 125 circulates the processing liquid LQ between the outer tank 110 and the processing tank 105 by introducing the processing liquid LQ from the outer tank 110 to the processing tank 105.

[0157] Next, in step S2, the substrate processing apparatus 100 supplies the first inert gas GA1 to the processing liquid LQ stored in the processing tank 105 while maintaining a constant flow rate of the first inert gas GA1. Specifically, the first control unit A1 controls the first gas adjustment unit 180 so that the flow rate of the first inert gas GA1 supplied to the first gas supply unit 200 is maintained at a constant level. As a result, the first gas supply unit 200 supplies the first inert gas GA1 to the processing liquid LQ in the processing tank 105 while maintaining a constant flow rate of the first inert gas GA1. In step S2, all valves 41 (Figure 8) are opened.

[0158] Next, in step S3, the substrate processing apparatus 100 supplies the third inert gas GA3 into the outer tank 110. Specifically, the third control unit A3 controls the third gas supply unit 210 to supply the third inert gas GA3. As a result, the third gas supply unit 210 supplies the third inert gas GA3 into the outer tank 110. In step S3, the valve 26 is opened.

[0159] Next, in step S4, the substrate processing apparatus 100 immerses the substrate W in the processing liquid LQ stored in the processing tank 105. Specifically, the control unit 221 controls the substrate holding unit 120 to immerse the substrate W in the processing liquid LQ of the processing tank 105. As a result, the substrate holding unit 120 descends, immersing the substrate W in the processing liquid LQ of the processing tank 105.

[0160] Next, in step S5, the substrate processing apparatus 100 measures the dissolved oxygen concentration of the processing liquid LQ. Specifically, the measurement unit 245 measures the dissolved oxygen concentration of the processing liquid LQ. The second control unit A2 then obtains information indicating the dissolved oxygen concentration of the processing liquid LQ from the measurement unit 245.

[0161] Next, in step S6, the substrate processing apparatus 100 (specifically, the second control unit A2) determines whether the dissolved oxygen concentration of the processing liquid LQ is within the target concentration range.

[0162] If it is determined in step S6 that the dissolved oxygen concentration of the treatment solution LQ is within the target concentration range (Yes), the process proceeds to step S8.

[0163] On the other hand, if it is determined in step S6 that the dissolved oxygen concentration of the treatment liquid LQ is not within the target concentration range (No), the process proceeds to step S7.

[0164] Next, in step S7, the substrate processing apparatus 100 supplies gas (mixed gas GA in the example of Figure 6) to the processing liquid LQ stored in the outer tank 110. Specifically, the second gas supply unit 230 supplies gas (mixed gas GA in the example of Figure 6) to the processing liquid LQ stored in the first storage unit 117a, which has the largest capacity among the first storage units 117a to the fourth storage units 117d. More specifically, the second gas supply unit 230 supplies gas (mixed gas GA in the example of Figure 6) from the bottom side of the first storage unit 117a, which has the largest capacity, toward the liquid surface of the processing liquid LQ. In this embodiment, the gas supplied to the processing liquid LQ in the outer tank 110 is a mixed gas GA, which is a mixture of the second inert gas GA2 and air AR. In other words, the gas used is the second inert gas GA2 and air AR. Therefore, in step S7, the second control unit A2 controls the second gas adjustment unit 240 to supply the mixed gas GA to the second gas supply unit 230. As a result, the second gas supply unit 230 supplies the mixed gas GA to the processing liquid LQ in the outer tank 110. In step S7, the valves 81 and / or 91 are opened by the control of the second control unit A2.

[0165] In particular, in this embodiment, in step S7, the substrate processing apparatus 100 adjusts the dissolved oxygen concentration of the processing liquid LQ stored in the processing tank 105 by adjusting the flow rate of the gas (mixed gas GA in the example of Figure 6) supplied to the processing liquid LQ of the outer tank 110 based on the dissolved oxygen concentration of the processing liquid LQ, while the flow rate of the first inert gas GA1 supplied to the processing liquid LQ of the processing tank 105 is kept constant. In this embodiment, the gas is a mixed gas GA, which is a mixture of a second inert gas GA2 and air AR. Therefore, in step S7, the second control unit A2 adjusts the flow rate of the mixed gas GA supplied to the processing liquid LQ of the outer tank 110 by controlling the second gas adjustment unit 240 based on the dissolved oxygen concentration of the processing liquid LQ, while the flow rate of the first inert gas GA1 is kept constant, thereby adjusting the dissolved oxygen concentration of the processing liquid LQ stored in the processing tank 105. Specifically, the second control unit A2 adjusts the dissolved oxygen concentration of the treatment liquid LQ by adjusting the ratio RA of the flow rate of the second inert gas GA2 to the flow rate of air AR using the second gas adjustment unit 240. Then the process proceeds to step S8.

[0166] After step S7, or after it is determined in step S6 that the dissolved oxygen concentration of the processing liquid LQ is within the target concentration range, in step S8, the substrate processing apparatus 100 (specifically, the control unit 221) determines whether a predetermined time has elapsed since the substrate W was immersed in the processing liquid LQ.

[0167] If it is determined that the predetermined time has not elapsed in step S8 (No), the process proceeds to step S5.

[0168] On the other hand, if it is determined that a predetermined time has elapsed in step S8 (Yes), the process proceeds to step S9.

[0169] Next, in step S9, the substrate processing apparatus 100 lifts the substrate W from the processing liquid LQ stored in the processing tank 105. Specifically, the control unit 221 controls the substrate holding unit 120 to lift the substrate W from the processing liquid LQ in the processing tank 105. As a result, the substrate holding unit 120 rises, thereby lifting the substrate W from the processing liquid LQ in the processing tank 105.

[0170] Next, in step S10, the substrate processing apparatus 100 (specifically, the control unit 221) determines whether or not processing with the processing solution LQ has been completed for all lots.

[0171] If it is determined in step S10 that processing is not complete for all lots (No), the process proceeds to step S4.

[0172] On the other hand, if it is determined in step S10 that processing has been completed for all lots (Yes), the substrate processing method is terminated. In this case, for example, the substrate processing apparatus 100 stops supplying the first inert gas GA1, the gas (mixed gas GA in the example in Figure 6), and the third inert gas GA3.

[0173] As described above with reference to Figure 10, the substrate processing method according to this embodiment maintains a constant flow rate of the first inert gas GA1 supplied to the processing liquid LQ in the processing tank 105, while adjusting the flow rate of the gas (mixed gas GA in the example of Figure 6) supplied to the processing liquid LQ in the outer tank 110 based on the measurement results of the dissolved oxygen concentration of the processing liquid LQ, thereby adjusting the dissolved oxygen concentration of the processing liquid LQ in the processing tank 105. Therefore, according to this embodiment, it is possible to keep the dissolved oxygen concentration of the processing liquid LQ within the target concentration range while suppressing the first inert gas GA1 supplied to the processing liquid LQ in the processing tank 105 from affecting the uniformity of processing within the plane of the substrate W and / or the uniformity of processing between multiple substrates W.

[0174] (First variation) A first modification of this embodiment will be described with reference to Figures 10 and 11. The first modification mainly differs from the above embodiment in that the second inert gas GA2 and air AR are supplied separately to the processing liquid LQ of the outer tank 110. The differences between the first modification and the above embodiment will be mainly described below.

[0175] Figure 11 is a schematic plan view showing a substrate processing apparatus 100 according to a first modified example of this embodiment. As shown in Figure 11, the substrate processing apparatus 100 includes a second gas supply unit 230A and a second gas adjustment unit 240A. In the first modified example, a second inert gas GA2 and air AR are used as the gas supplied by the second gas supply unit 230A to the processing liquid LQ of the outer tank 110.

[0176] The second gas supply unit 230A supplies the second inert gas GA2 and air AR separately to the processing liquid LQ of the outer tank 110. The second gas supply unit 230A is located approximately in the center of the first storage unit 117a in the first direction D10.

[0177] The second gas supply unit 230A includes at least one second gas supply pipe 70a and at least one second gas supply pipe 70b. In the first modified example, the second gas supply unit 230A includes one second gas supply pipe 70a and one second gas supply pipe 70b. The second gas supply pipes 70a and 70b are located on the bottom side of the outer tank 110. The second gas supply pipes 70a and 70b are immersed in the processing liquid LQ. The second gas supply pipes 70a and 70b extend along the second direction D20. The second gas supply pipes 70a and 70b are aligned in the first direction D10. For example, the second gas supply pipes 70a and 70b are adjacent in the first direction D10.

[0178] The second gas supply pipe 70a has a plurality of second discharge holes H2a. For example, the second discharge holes H2a face upward in the vertical direction D. The plurality of second discharge holes H2a are arranged in a nearly straight line with intervals between them in the second direction D20.

[0179] The second gas supply pipe 70a supplies bubbles BB2a (not shown) of the second inert gas GA2 to the processing liquid LQ of the outer tank 110 from each of the multiple second discharge holes H2a by discharging the second inert gas GA2 from each of the second discharge holes H2a.

[0180] The second gas supply pipe 70b has a plurality of second discharge holes H2b. For example, the second discharge holes H2b face upward in the vertical direction D. The plurality of second discharge holes H2b are arranged in a nearly straight line with intervals between them in the second direction D20.

[0181] The second gas supply pipe 70b supplies air bubbles BB2b (not shown) of air AR to the processing liquid LQ of the outer tank 110 from each of the multiple second discharge holes H2b by discharging air AR from each of the second discharge holes H2b.

[0182] Furthermore, the configuration and materials of the second gas supply pipes 70a and 70b are the same as those of the second gas supply pipe 70 (Figure 5).

[0183] The second gas supply section 230A further includes pipes 71a and 71b. Pipe 71a extends along the vertical direction D. One end (lower end) of pipe 71a is connected to one end of the second gas supply pipe 70a in the second direction D20. The other end (upper end) of pipe 71a is connected to piping 86. Thus, the second inert gas GA2 supplied from piping 86 is supplied to the second gas supply pipe 70a through pipe 71a. Meanwhile, pipe 71b extends along the vertical direction D. One end (lower end) of pipe 71b is connected to one end of the second gas supply pipe 70b in the second direction D20. The other end (upper end) of pipe 71b is connected to piping 96. Thus, the air AR supplied from piping 96 is supplied to the second gas supply pipe 70b through pipe 71b.

[0184] The second gas adjustment unit 240A includes check valves 72a and 72b, filters 73a and 73b, an inert gas adjustment mechanism 80, and an air adjustment mechanism 90. Filter 73a removes foreign matter from the second inert gas GA2 flowing through piping 86. Check valve 72a prevents backflow of the second inert gas GA2. Filter 73b removes foreign matter from the air AR flowing through piping 96. Check valve 72b prevents backflow of the air AR.

[0185] In particular, in the first modified example, the second gas adjustment unit 240A adjusts the ratio RA of the flow rate of the second inert gas GA2 to the flow rate of air AR supplied by the second gas supply unit 230 to the processing liquid LQ by adjusting the ratio RA of the flow rate of the second inert gas GA2 to the flow rate of air AR. In other words, the second gas adjustment unit 240A adjusts the ratio RA of the flow rate of the second inert gas GA2 supplied by the second gas supply pipe 70a to the processing liquid LQ to the processing liquid LQ to the processing liquid LQ to the flow rate of air AR supplied by the second gas supply pipe 70b by adjusting the ratio RA of the flow rate of the second inert gas GA2 to the flow rate of air AR. In this way, the second gas adjustment unit 240A adjusts the dissolved oxygen concentration of the processing liquid LQ in the processing tank 105 by adjusting the ratio RA of the flow rate of the second inert gas GA2 to the flow rate of air AR. Therefore, according to the first modified example, the dissolved oxygen concentration of the processing liquid LQ in the processing tank 105 can be easily adjusted by the simple operation of adjusting the ratio RA.

[0186] Specifically, if the dissolved oxygen concentration of the processing liquid LQ obtained from the measurement unit 245 is not within the target concentration range, the second control unit A2 controls the second gas adjustment unit 240A based on the dissolved oxygen concentration of the processing liquid LQ to adjust the ratio RA of the flow rate of the second inert gas GA2 to the flow rate of air AR so that the dissolved oxygen concentration of the processing liquid LQ is within the target concentration range.

[0187] More specifically, if the dissolved oxygen concentration of the processing liquid LQ obtained from the measurement unit 245 exceeds the target concentration range, the second control unit A2 controls the second gas adjustment unit 240A by increasing the proportion of the flow rate of the second inert gas GA2 supplied to the second gas supply pipe 70a so that the dissolved oxygen concentration falls within the target concentration range. Here, "proportion of the flow rate of the second inert gas GA2" refers to the proportion of the flow rate of the second inert gas GA2 to the total flow rate of the second inert gas GA2 and the air AR. Alternatively, if the dissolved oxygen concentration of the processing liquid LQ exceeds the target concentration range, the second control unit A2 may control the second gas adjustment unit 240A by decreasing the proportion of the flow rate of air AR supplied to the second gas supply pipe 70b so that the dissolved oxygen concentration falls within the target concentration range. Here, "proportion of the flow rate of air AR" refers to the proportion of the flow rate of air AR to the total flow rate of the second inert gas GA2 and the air AR.

[0188] Furthermore, the operation of the second control unit A2 and the second gas adjustment unit 240A when the dissolved oxygen concentration of the processing liquid LQ exceeds the target concentration range is the same as the operation of the second control unit A2 and the second gas adjustment unit 240 when the dissolved oxygen concentration of the processing liquid LQ exceeds the target concentration range, as explained with reference to Figures 5 to 7.

[0189] On the other hand, if the dissolved oxygen concentration of the processing liquid LQ obtained from the measurement unit 245 is below the target concentration range, the second control unit A2 controls the second gas adjustment unit 240A by reducing the flow rate ratio of the second inert gas GA2 supplied to the second gas supply pipe 70a so that the dissolved oxygen concentration falls within the target concentration range. Alternatively, if the dissolved oxygen concentration of the processing liquid LQ is below the target concentration range, the second control unit A2 may control the second gas adjustment unit 240A by increasing the flow rate ratio of air AR supplied to the second gas supply pipe 70b so that the dissolved oxygen concentration falls within the target concentration range.

[0190] Furthermore, the operation of the second control unit A2 and the second gas adjustment unit 240A when the dissolved oxygen concentration of the processing liquid LQ is below the target concentration range is the same as the operation of the second control unit A2 and the second gas adjustment unit 240 when the dissolved oxygen concentration of the processing liquid LQ is below the target concentration range, as explained with reference to Figures 5 to 7.

[0191] Next, the substrate processing method according to the first modified example will be described with reference to Figures 10 and 11. The substrate processing method according to the first modified example is the same as the substrate processing method described with reference to Figure 10. Therefore, the differences will be mainly explained with reference to Figure 10.

[0192] As shown in Figures 10 and 11, in the substrate processing method according to the first modified example, in step S7, the substrate processing apparatus 100 supplies gas (second inert gas GA2 and air AR in the example of Figure 11) to the processing liquid LQ stored in the outer tank 110 (specifically, the first storage unit 117a). Specifically, the second gas supply unit 230A supplies gas (second inert gas GA2 and air AR in the example of Figure 11) from the bottom side of the first storage unit 117a toward the liquid surface of the processing liquid LQ. In the first modified example, second inert gas GA2 and air AR are used as the gas supplied to the processing liquid LQ in the outer tank 110. Therefore, in step S7, the second control unit A2 controls the second gas adjustment unit 240A to supply the second inert gas GA2 and air AR separately to the second gas supply unit 230A. As a result, the second gas supply unit 230A supplies the second inert gas GA2 and air AR separately to the processing liquid LQ of the outer tank 110. In other words, the second gas supply pipe 70a supplies the second inert gas GA2 to the processing liquid LQ of the outer tank 110, and the second gas supply pipe 70b supplies air AR to the processing liquid LQ of the outer tank 110.

[0193] In particular, in the first modified example, in step S7, the substrate processing apparatus 100 adjusts the dissolved oxygen concentration of the processing liquid LQ stored in the processing tank 105 by adjusting the flow rate of gas (second inert gas GA2 and air AR in the example of Figure 11) supplied to the processing liquid LQ of the outer tank 110 based on the dissolved oxygen concentration of the processing liquid LQ, while the flow rate of the first inert gas GA1 supplied to the processing liquid LQ of the processing tank 105 is kept constant. In the first modified example, the second inert gas GA2 and air AR are used as gases. Therefore, in step S7, the second control unit A2 adjusts the dissolved oxygen concentration of the processing liquid LQ by adjusting the ratio RA of the flow rate of the second inert gas GA2 supplied to the second gas supply pipe 70a and the flow rate of air AR supplied to the second gas supply pipe 70b using the second gas adjustment unit 240A.

[0194] As explained above with reference to Figure 10, according to the substrate processing method of the first modified example, the flow rate of the first inert gas GA1 supplied to the processing liquid LQ of the processing tank 105 is kept constant, while the flow rate of the gas supplied to the processing liquid LQ of the outer tank 110 (second inert gas GA2 and air AR in the example of Figure 11) is adjusted based on the measurement results of the dissolved oxygen concentration of the processing liquid LQ, thereby adjusting the dissolved oxygen concentration of the processing liquid LQ of the processing tank 105. Therefore, according to the first modified example, the dissolved oxygen concentration of the processing liquid LQ can be kept within the target concentration range, while suppressing the effect of the first inert gas GA1 supplied to the processing liquid LQ of the processing tank 105 on the uniformity of processing within the plane of the substrate W and / or the uniformity of processing between multiple substrates W.

[0195] (Second variation) A second modification of this embodiment will be described with reference to Figures 10 and 12. The second modification mainly differs from the first modification in that it does not have a second gas supply pipe 70b for supplying air AR, but does have a second gas supply pipe 70a for supplying a second inert gas GA2. The differences between the second modification and the first modification will be mainly described below.

[0196] Figure 12 is a schematic plan view showing a substrate processing apparatus 100 according to a second modified example of this embodiment. As shown in Figure 12, the substrate processing apparatus 100 according to the second modified example has a configuration in which the second gas supply pipe 70b, pipe 71b, piping 96, check valve 72b, filter 73b, and air conditioning mechanism 90 are removed from the substrate processing apparatus 100 according to the first modified example (Figure 11).

[0197] In other words, the substrate processing apparatus 100 according to the second modified example includes a second gas supply unit 230B and a second gas adjustment unit 240B. In the second modified example, the gas supplied by the second gas supply unit 230B to the processing liquid LQ of the outer tank 110 is a second inert gas GA2.

[0198] The second gas supply unit 230B supplies the second inert gas GA2 to the processing liquid LQ in the outer tank 110. The second gas supply unit 230B is located approximately in the center of the first storage unit 117a in the first direction D10.

[0199] The second gas supply unit 230B includes at least one second gas supply pipe 70a. In the second modified example, the second gas supply unit 230A includes one second gas supply pipe 70a.

[0200] In particular, in the second modified example, the second gas adjustment unit 240B decreases the dissolved oxygen concentration of the treatment liquid LQ in the treatment tank 105 by increasing the flow rate of the second inert gas GA2, and increases the dissolved oxygen concentration of the treatment liquid LQ in the treatment tank 105 by decreasing the flow rate of the second inert gas GA2. Therefore, according to the second modified example, the dissolved oxygen concentration of the treatment liquid LQ in the treatment tank 105 can be easily adjusted by increasing or decreasing the flow rate of the second inert gas GA2.

[0201] Specifically, if the dissolved oxygen concentration of the processing liquid LQ obtained from the measurement unit 245 is not within the target concentration range, the second control unit A2 controls the second gas adjustment unit 240B based on the dissolved oxygen concentration of the processing liquid LQ to adjust the flow rate of the second inert gas GA2 so that the dissolved oxygen concentration of the processing liquid LQ is within the target concentration range.

[0202] More specifically, if the dissolved oxygen concentration of the processing liquid LQ obtained from the measurement unit 245 exceeds the target concentration range, the second control unit A2 controls the second gas adjustment unit 240B to increase the flow rate of the second inert gas GA2 so that the dissolved oxygen concentration falls within the target concentration range. As a result, the second gas adjustment unit 240B increases the flow rate of the second inert gas GA2 to a level higher than the flow rate of the second inert gas GA2 at the time of measurement of the dissolved oxygen concentration by the measurement unit 245 (the current flow rate of the second inert gas GA2). Therefore, the dissolved oxygen concentration of the processing liquid LQ in the outer tank 110 decreases, and the dissolved oxygen concentration falls within the target concentration range.

[0203] For example, if the dissolved oxygen concentration of the processing liquid LQ exceeds the target concentration range, the second control unit A2 controls the inert gas adjustment mechanism 80 (specifically the adjustment valve 82) to increase the flow rate of the second inert gas GA2, thereby bringing the dissolved oxygen concentration of the processing liquid LQ within the target concentration range.

[0204] Meanwhile, if the dissolved oxygen concentration of the processing liquid LQ obtained from the measurement unit 245 is below the target concentration range, the second control unit A2 controls the second gas adjustment unit 240B to reduce the flow rate of the second inert gas GA2 so that the dissolved oxygen concentration falls within the target concentration range. As a result, the second gas adjustment unit 240B reduces the flow rate of the second inert gas GA2 to less than the flow rate of the second inert gas GA2 at the time of measurement of the dissolved oxygen concentration by the measurement unit 245 (the current flow rate of the second inert gas GA2). Therefore, the dissolved oxygen concentration of the processing liquid LQ in the outer tank 110 increases, and the dissolved oxygen concentration falls within the target concentration range.

[0205] For example, if the dissolved oxygen concentration of the processing liquid LQ falls below the target concentration range, the second control unit A2 controls the inert gas adjustment mechanism 80 (specifically the adjustment valve 82) to reduce the flow rate of the second inert gas GA2, thereby bringing the dissolved oxygen concentration of the processing liquid LQ within the target concentration range.

[0206] Next, the substrate processing method according to the second modified example will be described with reference to Figures 10 and 12. The substrate processing method according to the second modified example is the same as the substrate processing method described with reference to Figure 10. Therefore, the differences will be mainly explained with reference to Figure 10.

[0207] As shown in Figures 10 and 12, in the substrate processing method according to the second modified example, in step S7, the substrate processing apparatus 100 supplies gas (second inert gas GA2 in the example of Figure 12) to the processing liquid LQ stored in the outer tank 110 (specifically, the first storage section 117a). Specifically, the second gas supply unit 230B supplies gas (second inert gas GA2 in the example of Figure 12) from the bottom side of the first storage section 117a toward the liquid surface of the processing liquid LQ. In the second modified example, the gas supplied to the processing liquid LQ in the outer tank 110 is second inert gas GA2. Therefore, in step S74, the second control unit A2 controls the second gas adjustment unit 240B to supply second inert gas GA2 to the second gas supply unit 230B. As a result, the second gas supply unit 230B supplies second inert gas GA2 to the processing liquid LQ in the outer tank 110. In other words, the second gas supply pipe 70a supplies the second inert gas GA2 to the processing liquid LQ in the outer tank 110.

[0208] In particular, in the second modified example, in step S7, the substrate processing apparatus 100 adjusts the dissolved oxygen concentration of the processing liquid LQ stored in the processing tank 105 by adjusting the flow rate of the gas (second inert gas GA2 in the example of Figure 12) supplied to the processing liquid LQ of the outer tank 110 based on the dissolved oxygen concentration of the processing liquid LQ, while the flow rate of the first inert gas GA1 supplied to the processing liquid LQ of the processing tank 105 is kept constant. In the second modified example, the gas is the second inert gas GA2. Therefore, in step S7, the second control unit A2 adjusts the flow rate of the second inert gas GA2 supplied to the processing liquid LQ of the outer tank 110 by controlling the second gas adjustment unit 240B based on the dissolved oxygen concentration of the processing liquid LQ, while the flow rate of the first inert gas GA1 is kept constant, thereby adjusting the dissolved oxygen concentration of the processing liquid LQ stored in the processing tank 105. Specifically, the second control unit A2 decreases the dissolved oxygen concentration of the processing liquid LQ by increasing the flow rate of the second inert gas GA2 supplied to the second gas supply pipe 70a, and increases the dissolved oxygen concentration of the processing liquid LQ by decreasing the flow rate of the second inert gas GA2 supplied to the second gas supply pipe 70a.

[0209] As explained above with reference to Figure 10, according to the second modified substrate processing method, the flow rate of the first inert gas GA1 supplied to the processing liquid LQ in the processing tank 105 is kept constant, while the flow rate of the gas supplied to the processing liquid LQ in the outer tank 110 (second inert gas GA2 in the example of Figure 12) is adjusted based on the measurement results of the dissolved oxygen concentration of the processing liquid LQ, thereby adjusting the dissolved oxygen concentration of the processing liquid LQ in the processing tank 105. Therefore, according to the second modified method, the dissolved oxygen concentration of the processing liquid LQ can be kept within the target concentration range, while suppressing the effect of the first inert gas GA1 supplied to the processing liquid LQ in the processing tank 105 on the uniformity of processing within the plane of the substrate W and / or the uniformity of processing between multiple substrates W.

[0210] Furthermore, by closing the valve 91 in Figure 5, the substrate processing apparatus 100 in Figure 5 can operate in the same manner as the substrate processing apparatus 100 according to the second modified example.

[0211] (Third variation) A third modification of this embodiment will be described with reference to Figures 10 and 13. The third modification mainly differs from the first modification in that it does not have a second gas supply pipe 70a for supplying the second inert gas GA2, but does have a second gas supply pipe 70b for supplying air AR. The differences between the third modification and the first modification will be mainly described below.

[0212] Figure 13 is a schematic plan view showing a substrate processing apparatus 100 according to a third modified example of this embodiment. As shown in Figure 13, the substrate processing apparatus 100 according to the third modified example has a configuration in which the second gas supply pipe 70a, pipe 71a, piping 86, check valve 72a, filter 73a, and inert gas adjustment mechanism 80 are removed from the substrate processing apparatus 100 according to the first modified example (Figure 11).

[0213] In other words, the substrate processing apparatus 100 according to the third modified example includes a second gas supply unit 230C and a second gas adjustment unit 240C. In the third modified example, the gas supplied by the second gas supply unit 230C to the processing liquid LQ of the outer tank 110 is air AR.

[0214] The second gas supply unit 230C supplies air AR to the processing liquid LQ in the outer tank 110. The second gas supply unit 230C is located approximately in the center of the first storage unit 117a in the first direction D10.

[0215] The second gas supply unit 230C includes at least one second gas supply pipe 70b. In the third modified example, the second gas supply unit 230C includes one second gas supply pipe 70b.

[0216] In particular, in the third modified example, the second gas adjustment unit 240C reduces the dissolved oxygen concentration of the treatment liquid LQ in the treatment tank 105 by decreasing the flow rate of air AR, and increases the dissolved oxygen concentration of the treatment liquid LQ in the treatment tank 105 by increasing the flow rate of air AR. Therefore, according to the third modified example, the dissolved oxygen concentration of the treatment liquid LQ in the treatment tank 105 can be easily adjusted by increasing or decreasing the flow rate of air AR.

[0217] Specifically, if the dissolved oxygen concentration of the processing liquid LQ obtained from the measurement unit 245 is not within the target concentration range, the second control unit A2 controls the second gas adjustment unit 240C based on the dissolved oxygen concentration of the processing liquid LQ to adjust the flow rate of air AR so that the dissolved oxygen concentration of the processing liquid LQ is within the target concentration range.

[0218] More specifically, if the dissolved oxygen concentration of the processing liquid LQ obtained from the measurement unit 245 exceeds the target concentration range, the second control unit A2 controls the second gas adjustment unit 240C to reduce the flow rate of air AR so that the dissolved oxygen concentration falls within the target concentration range. As a result, the second gas adjustment unit 240C reduces the flow rate of air AR to less than the flow rate of air AR at the time of measurement of the dissolved oxygen concentration by the measurement unit 245 (the current flow rate of air AR). Therefore, the dissolved oxygen concentration of the processing liquid LQ in the outer tank 110 decreases, and the dissolved oxygen concentration falls within the target concentration range.

[0219] For example, if the dissolved oxygen concentration of the processing liquid LQ exceeds the target concentration range, the second control unit A2 controls the air adjustment mechanism 90 (specifically the adjustment valve 92) to reduce the flow rate of air AR, thereby bringing the dissolved oxygen concentration of the processing liquid LQ within the target concentration range.

[0220] Meanwhile, if the dissolved oxygen concentration of the processing liquid LQ obtained from the measurement unit 245 is below the target concentration range, the second control unit A2 controls the second gas adjustment unit 240C to increase the flow rate of air AR so that the dissolved oxygen concentration falls within the target concentration range. As a result, the second gas adjustment unit 240C increases the flow rate of air AR to a level higher than the flow rate of air AR at the time of measurement of the dissolved oxygen concentration by the measurement unit 245 (the current flow rate of air AR). Therefore, the dissolved oxygen concentration of the processing liquid LQ in the outer tank 110 increases, and the dissolved oxygen concentration falls within the target concentration range.

[0221] For example, if the dissolved oxygen concentration of the processing liquid LQ falls below the target concentration range, the second control unit A2 controls the air adjustment mechanism 90 (specifically the adjustment valve 92) to increase the flow rate of air AR, thereby bringing the dissolved oxygen concentration of the processing liquid LQ within the target concentration range.

[0222] Next, the substrate processing method according to the third modified example will be described with reference to Figures 10 and 13. The substrate processing method according to the third modified example is the same as the substrate processing method described with reference to Figure 10. Therefore, the differences will be mainly explained with reference to Figure 10.

[0223] As shown in Figures 10 and 13, in the third modified substrate processing method, in step S7, the substrate processing apparatus 100 supplies gas (air AR in the example of Figure 13) to the processing liquid LQ stored in the outer tank 110 (specifically, the first storage section 117a). Specifically, the second gas supply section 230C supplies gas (air AR in the example of Figure 13) from the bottom side of the first storage section 117a toward the liquid surface of the processing liquid LQ. In the third modified example, the gas supplied to the processing liquid LQ in the outer tank 110 is air AR. Therefore, in step S7, the second control unit A2 controls the second gas adjustment unit 240C to supply air AR to the second gas supply unit 230C. As a result, the second gas supply unit 230C supplies air AR to the processing liquid LQ in the outer tank 110. In other words, the second gas supply pipe 70b supplies air AR to the processing liquid LQ in the outer tank 110.

[0224] In particular, in the third modified example, in step S7, the substrate processing apparatus 100 adjusts the dissolved oxygen concentration of the processing liquid LQ stored in the processing tank 105 by adjusting the flow rate of gas (air AR in the example of Figure 13) supplied to the processing liquid LQ of the outer tank 110 based on the dissolved oxygen concentration of the processing liquid LQ, while the flow rate of the first inert gas GA1 supplied to the processing liquid LQ of the processing tank 105 is kept constant. In the third modified example, the gas is air AR. Therefore, in step S7, the second control unit A2 adjusts the flow rate of air AR supplied to the processing liquid LQ of the outer tank 110 by controlling the second gas adjustment unit 240C based on the dissolved oxygen concentration of the processing liquid LQ, while the flow rate of the first inert gas GA1 is kept constant, thereby adjusting the dissolved oxygen concentration of the processing liquid LQ stored in the processing tank 105. Specifically, the second control unit A2 decreases the dissolved oxygen concentration of the processing liquid LQ by reducing the flow rate of air AR supplied to the second gas supply pipe 70b, and increases the dissolved oxygen concentration of the processing liquid LQ by increasing the flow rate of air AR supplied to the second gas supply pipe 70b.

[0225] As explained above with reference to Figure 10, according to the third modified substrate processing method, the flow rate of the first inert gas GA1 supplied to the processing liquid LQ in the processing tank 105 is kept constant, while the flow rate of the gas (air AR in the example of Figure 13) supplied to the processing liquid LQ in the outer tank 110 is adjusted based on the measurement results of the dissolved oxygen concentration of the processing liquid LQ, thereby adjusting the dissolved oxygen concentration of the processing liquid LQ in the processing tank 105. Therefore, according to the third modified method, the dissolved oxygen concentration of the processing liquid LQ can be kept within the target concentration range, while suppressing the effect of the first inert gas GA1 supplied to the processing liquid LQ in the processing tank 105 on the uniformity of processing within the plane of the substrate W and / or the uniformity of processing between multiple substrates W.

[0226] Furthermore, by closing the valve 81 in Figure 5, the substrate processing apparatus 100 in Figure 5 can operate in the same manner as the substrate processing apparatus 100 according to the third modified example.

[0227] Embodiments of the present invention (including modifications) have been described above with reference to the drawings. However, the present invention is not limited to the embodiments described above, and can be implemented in various forms without departing from its spirit. Furthermore, the multiple components disclosed in the above embodiments can be modified as appropriate. For example, some components from all the components shown in one embodiment may be added to the components of another embodiment, or some components from all the components shown in one embodiment may be deleted from the embodiment.

[0228] Furthermore, the drawings schematically show each component in order to facilitate understanding of the invention, and the thickness, length, number, spacing, etc. of each component shown may differ from the actual dimensions due to the convenience of drawing creation. Also, the configuration of each component shown in the above embodiments is merely an example and is not particularly limiting, and it goes without saying that various modifications are possible without substantially departing from the effects of the present invention.

[0229] (1) In Figure 5, multiple second gas supply pipes 70 may be connected to piping 74. In Figure 11, multiple second gas supply pipes 70a may be connected to piping 86. Also, multiple second gas supply pipes 70b may be connected to piping 96. Furthermore, in Figure 12, multiple second gas supply pipes 70a may be connected to piping 86. Furthermore, in Figure 13, multiple second gas supply pipes 70b may be connected to piping 96.

[0230] (2) In Figure 6, the third gas supply pipe 25 may be placed in the processing liquid LQ of the outer tank 110. That is, the third gas supply pipe 25 may be immersed in the processing liquid LQ. In this case, the third discharge port H3 of the third gas supply pipe 25 faces, for example, upward in the vertical direction D.

[0231] (3) In Figure 10, the order of processes S1 to S8 is not particularly limited and can be any order. [Industrial applicability]

[0232] The present invention relates to a substrate processing method and a substrate processing apparatus, and has industrial applicability. [Explanation of Symbols]

[0233] 100 Substrate Processing Equipment 105 Processing tank 110 Outer tank 117a First Storage Section (Storage Section) 125 Processing liquid introduction section 141 Circulation piping (piping) 200 First Gas Supply Department 230, 230A~230C Second Gas Supply Section 240, 240A~240C Second Gas Regulation Section (Gas Regulation Section) A1 First Control Unit A2 Second Control Unit (Gas Control Unit) A3 Third Control Unit W board

Claims

1. A substrate processing method performed in a substrate processing apparatus comprising a processing tank for storing a processing liquid into which a substrate is immersed, and an outer tank disposed outside the processing tank for storing the processing liquid, wherein the processing liquid is circulated between the processing tank and the outer tank, A step of supplying the first inert gas to the processing liquid stored in the processing tank while maintaining a constant flow rate of the first inert gas, A step of measuring the dissolved oxygen concentration of the processing liquid, A step of supplying gas to the processing liquid stored in the outer tank. Includes, A substrate processing method comprising the step of supplying the gas, wherein the flow rate of the first inert gas is kept constant, and the flow rate of the gas is adjusted based on the dissolved oxygen concentration of the processing liquid, thereby adjusting the dissolved oxygen concentration of the processing liquid stored in the processing tank.

2. As the aforementioned gases, a second inert gas and air are used. The substrate processing method according to claim 1, wherein in the step of supplying the gas, the dissolved oxygen concentration of the processing liquid is adjusted by adjusting the ratio of the flow rate of the second inert gas to the flow rate of the air.

3. The aforementioned gas is a second inert gas, The substrate processing method according to claim 1, wherein in the step of supplying the gas, the dissolved oxygen concentration of the processing liquid is reduced by increasing the flow rate of the second inert gas, and the dissolved oxygen concentration of the processing liquid is increased by reducing the flow rate of the second inert gas.

4. The aforementioned gas is air. The substrate processing method according to claim 1, wherein in the step of supplying the gas, the dissolved oxygen concentration of the processing liquid is reduced by reducing the flow rate of the air, and the dissolved oxygen concentration of the processing liquid is increased by increasing the flow rate of the air.

5. The outer tank has a plurality of storage sections that are in communication with each other, The substrate processing method according to any one of claims 1 to 4, wherein in the step of supplying the gas, the gas is supplied to the processing liquid stored in the storage unit with the largest capacity among the plurality of storage units.

6. A pipe for introducing the processing liquid into the processing tank is connected to the bottom of the largest storage section. The substrate processing method according to claim 5, wherein in the step of supplying the gas, the gas is supplied from the bottom of the largest storage section toward the liquid surface of the processing liquid.

7. A treatment tank for storing the treatment solution into which the substrate is immersed, An outer tank is located outside the aforementioned treatment tank, into which the treatment liquid that overflows from the aforementioned treatment tank flows; A processing liquid introduction unit for introducing the processing liquid stored in the outer tank into the processing tank, A first gas supply unit that supplies the inert gas to the processing liquid stored in the processing tank while maintaining a constant flow rate of the inert gas, A second gas supply unit that supplies gas to the processing liquid stored in the outer tank, A gas adjustment unit that adjusts the flow rate of the gas supplied to the second gas supply unit, A measuring unit for measuring the dissolved oxygen concentration of the processing liquid, A gas control unit adjusts the flow rate of the gas by controlling the gas adjustment unit based on the dissolved oxygen concentration of the processing liquid, while the flow rate of the inert gas is kept constant, thereby adjusting the dissolved oxygen concentration of the processing liquid stored in the processing tank. A substrate processing apparatus comprising:

Images