Substrate processing apparatus and substrate processing method

Abstract

To provide a substrate processing apparatus which can effectively process a substrate by increasing an effectiveness of inactive gas.SOLUTION: A substrate processing apparatus 100 comprises: a processing tank 105; a first lid body 111; an outer tank 110; a processing liquid introduction portion 125; a first gas supply portion 200; and a second gas supply portion 210. The processing tank 105 accumulates a processing liquid LQ in which a substrate W is immersed. The first lid body 111 covers an upper open 106a of the processing tank 105. The outer tank 110 is arranged outside the processing tank 105, and the processing liquid LQ that is the processing liquid LQ leaked from the processing tank 105, flows into the outer tank 110. The processing liquid introduction portion 125 can introduce the processing liquid LQ accumulated in the outer tank 110 into the processing tank 105. The first gas supply portion 200 supplies first inactive gas GA1 to the processing liquid LQ accumulated in the processing tank 105. The second gas supply portion 210 supplies second inactive gas GA2 into the inside of the outer tank 110.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] The substrate processing apparatus described in Patent Document 1 includes a processing tank, a substrate holding unit, a fluid supply unit, and a control unit. The processing tank stores a processing liquid for processing a substrate. The substrate holding unit holds a substrate in the processing liquid in the processing tank. The fluid supply unit supplies a fluid to the processing tank. The fluid is a gas. The control unit controls the fluid supply unit. The control unit controls the fluid supply unit so that the fluid supply unit changes the supply of fluid between the start of supplying the fluid to the processing tank storing the processing liquid in which the substrate is immersed and the end of supplying the fluid to the processing tank storing the processing liquid in which the substrate is immersed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-47885 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the substrate processing apparatus described in Patent Document 1, the fluid supply unit supplies an inert gas to the inner tank of the processing tank, which merely forms bubbles in the processing liquid stored in the inner tank, and therefore the effectiveness of the inert gas is limited.

[0005] Therefore, the inventors of the present application have conducted extensive research into techniques that can increase the effectiveness of inert gases and effectively process substrates.

[0006] An object of the present invention is to provide a substrate processing apparatus and a substrate processing method that can increase the effectiveness of an inert gas to process a substrate effectively. [Means for solving the problem]

[0007] According to one aspect of the present invention, a substrate processing apparatus includes a processing tank, a first lid, an outer tank, a processing liquid introduction unit, a first gas supply unit, and a second gas supply unit. The processing tank stores a processing liquid in which a substrate is immersed. The first lid covers an upper opening of the processing tank. The outer tank is disposed outside the processing tank, and receives processing liquid that overflows from the processing tank. The processing liquid introduction unit can introduce the processing liquid stored in the outer tank into the processing tank. The first gas supply unit supplies a first inert gas to the processing liquid stored in the processing tank. The second gas supply unit supplies a second inert gas into the outer tank.

[0008] In one aspect of the present invention, the substrate processing apparatus preferably further includes a substrate holding unit. The substrate holding unit preferably holds the plurality of substrates along a predetermined direction and immerses the plurality of substrates in the processing liquid stored in the processing tank. The processing tank preferably includes a pair of side walls extending along the predetermined direction. The first lid preferably includes a contact portion that contacts the processing liquid. The contact portion is preferably spaced apart from the plurality of substrates. The contact portion preferably includes a first inclined portion and a second inclined portion. The first inclined portion preferably slopes obliquely upward from a position facing the tops of the plurality of substrates toward one of the pair of side walls when the first lid covers the upper opening of the processing tank. The second inclined portion preferably slopes obliquely upward from a position facing the tops of the plurality of substrates toward the other of the pair of side walls when the first lid covers the upper opening of the processing tank.

[0009] In one aspect of the present invention, it is preferable that the second gas supply unit is disposed inside the outer tank and discharges the second inert gas downward.

[0010] In one aspect of the present invention, it is preferable that the second gas supply unit is disposed inside the outer tank and discharges the second inert gas upward.

[0011] In one aspect of the present invention, the substrate processing apparatus preferably further includes a gas flow rate regulator and a first control unit. The gas flow rate regulator preferably regulates the flow rate of the first inert gas. The first control unit preferably controls the gas flow rate regulator. The first control unit preferably controls the gas flow rate regulator so that the flow rate of the first inert gas during a period when the substrate is not immersed in the processing liquid is greater than the flow rate of the first inert gas during a period when the substrate is immersed in the processing liquid.

[0012] In one aspect of the present invention, it is preferable that the first control unit controls the gas flow rate adjustment unit so that the flow rate of the first inert gas becomes a maximum flow rate during the period when the substrate is not immersed in the processing liquid.

[0013] In one aspect of the present invention, the processing liquid introduction unit preferably includes a pipe and a pump. The pipe preferably connects the outer bath and the processing bath, and the processing liquid flows through the pipe. The pump preferably delivers the processing liquid from the outer bath to the processing bath via the pipe. The substrate processing apparatus preferably further includes a second control unit that controls the pump. The second control unit preferably controls the pump so that the flow rate of the processing liquid flowing through the pipe during a period in which the substrate is immersed in the processing liquid is smaller than the flow rate of the processing liquid flowing through the pipe during a period in which the substrate is not immersed in the processing liquid.

[0014] In one aspect of the present invention, it is preferable that the second control unit stops the pump during the period in which the substrate is immersed in the processing liquid.

[0015] In one aspect of the present invention, it is preferable that the second control unit controls the pump so that the flow rate of the processing liquid flowing through the piping becomes a maximum flow rate during the period when the substrate is not immersed in the processing liquid.

[0016] In one aspect of the present invention, the substrate processing apparatus preferably further includes a second lid, the second lid preferably covering an upper opening of the outer tank, and the first lid preferably covering the upper opening of the processing tank and the second lid.

[0017] In one aspect of the present invention, the treatment liquid is preferably alkaline.

[0018] According to another aspect of the present invention, a substrate processing method includes: Immerse The substrate processing method is performed by a substrate processing apparatus including a processing tank for storing a processing liquid to be processed, an outer tank into which the processing liquid overflowing from the processing tank flows, and a processing liquid introduction part capable of introducing the processing liquid stored in the outer tank into the processing tank. The substrate processing method includes a first gas supply step and a second gas supply step. In the first gas supply step, a first inert gas is supplied to the processing liquid stored in the processing tank. In the second gas supply step, a second inert gas is supplied into the outer tank. In one aspect of the present invention, it is preferable that the substrate processing method further includes a step of controlling the flow rate of the first inert gas so that the flow rate of the first inert gas during a period when the substrate is not immersed in the processing liquid is greater than the flow rate of the first inert gas during a period when the substrate is immersed in the processing liquid. In one aspect of the present invention, the processing liquid introduction part preferably includes a pipe connecting the outer bath and the processing bath and through which the processing liquid flows, and a pump that delivers the processing liquid from the outer bath to the processing bath through the pipe. Preferably, the substrate processing method further includes a step of controlling the pump so that a flow rate of the processing liquid flowing through the pipe during a period in which the substrate is immersed in the processing liquid is smaller than a flow rate of the processing liquid flowing through the pipe during a period in which the substrate is not immersed in the processing liquid. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a substrate processing apparatus and a substrate processing method that can increase the effectiveness of an inert gas to effectively process a substrate. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a schematic cross-sectional view showing a substrate processing apparatus according to an embodiment of the present invention. [Figure 2] 10 is a graph showing the relationship between the dissolved oxygen concentration and the etching amount of the treatment liquid according to the present embodiment. [Figure 3] 10 is a graph showing the relationship between the bubble supply time and the dissolved oxygen concentration in the treatment liquid according to the present embodiment. [Figure 4] 1A is a diagram showing a state of a substrate according to the present embodiment before it is immersed in a processing liquid, and FIG. 1B is a diagram showing a state of a substrate according to the present embodiment after it has been immersed in a processing liquid. [Figure 5] 1 is a schematic plan view showing the substrate processing apparatus when the first and second lids according to the present embodiment are removed. FIG. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5. [Figure 7] FIG. 2 is a schematic plan view showing the substrate processing apparatus according to the present embodiment when a first lid body is removed. [Figure 8] FIG. 2 is a schematic plan view showing a first lid according to the embodiment. [Figure 9] 1A is a schematic diagram showing a state in which the first lid according to the present embodiment is closed, and FIG. 1B is a schematic diagram showing a state in which the first lid according to the present embodiment is open. [Figure 10] FIG. 2 is a schematic plan view showing a first gas supply unit according to the embodiment. [Figure 11] FIG. 4 is a schematic rear view showing an introduction section according to the present embodiment. [Figure 12] 10A and 10B are diagrams illustrating control of the dissolved oxygen concentration of the treatment liquid in the treatment tank according to the present embodiment. [Figure 13] 10 is a flowchart showing the first stage of a substrate processing method according to the present embodiment. [Figure 14] 10 is a flowchart showing the latter stage of the substrate processing method according to the embodiment. [Figure 15] 10 is a flowchart showing the latter stage of another example of the substrate processing method according to the present embodiment. [Figure 16] FIG. 10 is a schematic cross-sectional view showing a substrate processing apparatus according to a first modified example of the present embodiment. [Figure 17] FIG. 10 is a schematic diagram showing a state in which a first cover according to a first modified example is closed. [Figure 18] FIG. 10 is a schematic cross-sectional view showing a substrate processing apparatus according to a second modified example of the present embodiment. [Figure 19] FIG. 10 is a schematic cross-sectional view showing an outer tank and a second gas supply pipe according to a second modified example. [Figure 20] 4 is a graph showing the change over time in the dissolved oxygen concentration of the treatment liquid in Example 1 of the present invention (without the first inert gas). [Figure 21]10 is a graph showing the change over time in the dissolved oxygen concentration of the treatment liquid (with the first inert gas) in Example 2 of the present invention. [Figure 22] 10 is a graph showing the change over time in the dissolved oxygen concentration of the treatment liquid for each flow rate of the first inert gas in Example 3 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated. In addition, in the drawings, the X-axis, Y-axis, and Z-axis are appropriately illustrated to facilitate understanding. The X-axis, Y-axis, and Z-axis are mutually orthogonal, the X-axis and Y-axis are parallel to the horizontal direction, and the Z-axis is parallel to the vertical direction. In addition, "plan view" means viewing an object from vertically above. "Rear view" means viewing an object from vertically below.

[0022] A substrate processing apparatus 100 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 15. First, the substrate processing apparatus 100 will be described with reference to FIG. 1. FIG. 1 is a schematic cross-sectional view showing the substrate processing apparatus 100. The substrate processing apparatus 100 shown in FIG. 1 is a batch type apparatus that processes a plurality of substrates W collectively using a processing liquid LQ. The substrate processing apparatus 100 can also process a single substrate W.

[0023] The substrate processing apparatus 100 includes a processing tank 105, an outer tank 110, a first lid 111, a second lid 112, a substrate holder 120, a processing liquid introduction section 125, a drainage section 170, a gas flow rate adjustment section 180, a first gas supply section 200, a second gas supply section 210, and a control device 220.

[0024] The processing tank 105 stores a processing liquid LQ in which a plurality of substrates W are immersed. The processing tank 105 is capable of accommodating a plurality of substrates W. The processing tank 105 immerses the plurality of substrates W in the processing liquid LQ to process the plurality of substrates W. The processing liquid LQ is, for example, an etching liquid.

[0025] In the following, in this embodiment, as an example, a case where the processing liquid LQ is alkaline will be described. The alkaline processing liquid LQ is, for example, an aqueous solution containing tetramethylammonium hydroxide (TMAH), an aqueous solution containing trimethyl-2-hydroxyethylammonium hydroxide (TMY), ammonium hydroxide (aqueous ammonia), or an ammonia-hydrogen peroxide solution mixture (SC1). The alkaline processing liquid LQ is, for example, an alkaline etching liquid (hereinafter referred to as "alkaline etching liquid").

[0026] The first lid 111 covers the upper opening 106a of the treatment tank 105. The upper opening 106a opens upward in the vertical direction D. The first lid 111 is made of, for example, a synthetic resin. For example, the material of the first lid 111 is polytetrafluoroethylene (PTFE). The first lid 111 includes a separation portion 51 and a contact portion 52. The separation portion 51 is separated from the treatment liquid LQ in the treatment tank 105 when the first lid 111 is closed. The separation portion 51 has, for example, a substantially flat plate shape. When the first lid 111 is closed, the contact portion 52 contacts the treatment liquid LQ from above the treatment liquid LQ in the treatment tank 105. Specifically, when the first lid 111 is closed, the lower portion of the contact portion 52 contacts the treatment liquid LQ in the treatment tank 105. 1, when the first lid 111 is closed, the lower part of the contact portion 52 enters the processing tank 105 from the upper opening 106a and is immersed in the processing liquid LQ in the processing tank 105. Furthermore, when the first lid 111 is closed, the contact portion 52 is spaced apart in the vertical direction D from the plurality of substrates W. The contact portion 52 has, for example, a substantially flat plate shape.

[0027] The outer tank 110 is disposed outside the processing tank 105. The outer tank 110 surrounds the processing tank 105. The processing liquid LQ stored in the processing tank 105 and overflowing from the processing 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 processing tank 105.

[0028] 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 treatment tank 105. The treatment liquid LQ that overflows from the treatment tank 105 flows into the outer tank 110 through the gap 110b. The second lid 112 is made of, for example, a synthetic resin. For example, the material of the second lid 112 is PTFE.

[0029] The substrate holding unit 120 holds a plurality of substrates W. The substrate holding unit 120 can also hold a single substrate W. The substrate holding unit 120 immerses the plurality of substrates W, which are aligned at intervals, in the processing liquid LQ stored in the processing bath 105.

[0030] The processing liquid introduction part 125 is capable of introducing the processing liquid LQ stored in the outer bath 110 into the processing bath 105. The liquid drainage part 170 discharges the processing liquid LQ from the processing bath 105.

[0031] The first gas supply unit 200 supplies a first inert gas GA1 to the processing liquid LQ stored in the processing tank 105. The first gas supply unit 200 is disposed inside the processing tank 105. The first inert gas GA1 is, for example, nitrogen or argon. Specifically, the first gas supply unit 200 supplies bubbles BB of the first inert gas GA1 to the processing liquid LQ stored in the processing tank 105.

[0032] Specifically, 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 disposed inside the processing tank 105. The plurality of first gas supply pipes 21 are disposed on the bottom side of the processing tank 105. Each of the plurality of first gas supply pipes 21 has a plurality of first discharge holes H1. Each of the plurality of first gas supply pipes 21 discharges a first inert gas GA1 from each of the plurality of first discharge holes H1, thereby supplying bubbles BB from each of the plurality of first discharge holes H1 to the processing liquid LQ. Specifically, while the substrate W is immersed in the processing liquid LQ, each of the plurality of first gas supply pipes 21 supplies bubbles BB from each of the plurality of first discharge holes H1 to the processing liquid LQ from below the substrate W. The first gas supply pipes 21 are, for example, bubbler pipes. The material of the first gas supply pipe 21 is, for example, quartz or resin. The diameter of the first gas supply pipe 21 is not particularly limited, but is, for example, about 6.0 mm. The diameter of the first discharge hole H1 is not particularly limited, but is, for example, about 0.2 mm.

[0033] The gas flow rate adjuster 180 adjusts the flow rate of the first inert gas GA1 supplied to the first gas supply unit 200. Specifically, the gas flow rate adjuster 180 adjusts the flow rate of the first inert gas GA1 supplied to the first gas supply unit 200, thereby adjusting the bubbles BB supplied by the first gas supply unit 200 to the processing liquid LQ. More specifically, the gas flow rate adjuster 180 adjusts the flow rate of the first inert gas GA1 supplied to each first gas supply pipe 21, thereby adjusting the bubbles BB supplied by each first gas supply pipe 21 to the processing liquid LQ from the multiple first discharge holes H1.

[0034] The second gas supply unit 210 supplies a second inert gas GA2 into the outer tank 110. The second gas supply unit 210 is disposed inside the outer tank 110. 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. Specifically, the second gas supply unit 210 includes a second gas supply pipe 25. The second gas supply pipe 25 is disposed inside the processing tank 105. The second gas supply pipe 25 has a plurality of second discharge holes H2. The second gas supply pipe 25 discharges the second inert gas GA2 into the outer tank 110 from each of the plurality of second discharge holes H2. The second gas supply pipe 25 is made of, for example, quartz or resin. The diameter of the second gas supply pipe 25 is not particularly limited, but is, for example, approximately 6.0 mm. The diameter of the second discharge holes H2 is not particularly limited, but is, for example, approximately 0.2 mm.

[0035] The control device 220 controls each component of the substrate processing apparatus 100. Specifically, the control device 220 controls the first lid 111, the substrate holder 120, the processing liquid introduction unit 125, the drainage unit 170, the gas flow rate adjuster 180, and the second gas supply unit 210.

[0036] Specifically, the control device 220 includes a control unit 221 and a memory unit 223. The control unit 221 includes a processor such as a CPU (Central Processing Unit). The memory unit 223 includes a storage device and stores data and computer programs. The processor of the control unit 221 executes the computer programs stored in the storage device of the memory unit 223 to control each component of the substrate processing apparatus 100. For example, the memory 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 memory unit 223 may include removable media such as an optical disk. The memory unit 223 is, for example, a non-transitory computer-readable storage medium. The control device 220 may include an input device and a display device.

[0037] As described above with reference to FIG. 1 , according to this embodiment, the first gas supply unit 200 supplies the first inert gas GA1 (bubbles BB) to the processing liquid LQ in the processing tank 105, thereby replacing oxygen dissolved in the processing liquid LQ with the first inert gas GA1. Therefore, the dissolved oxygen concentration of the processing liquid LQ in the processing tank 105 can be reduced compared to when the first inert gas GA1 is not supplied. 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 (bubbles BB), the dissolved oxygen concentration of the processing liquid LQ is reduced, and therefore the amount of substrate W processed by the processing liquid LQ can be increased compared to when 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 substrate W processed by the processing liquid LQ is the amount of etching of the substrate W. Therefore, by supplying the first inert gas GA1 (bubbles BB), the amount of etching of the substrate W by the processing liquid LQ can be increased.

[0038] Furthermore, when the processing liquid LQ is alkaline, the amount of substrates W processed by the processing liquid LQ can be increased by reducing the dissolved oxygen concentration of the processing liquid LQ using the first inert gas GA1 (air bubbles BB). As a result, the throughput when processing the substrates W can be improved.

[0039] In particular, in this embodiment, since the second inert gas GA2 is supplied into the outer tank 110, dissolution of oxygen in the processing liquid LQ in the outer tank 110 can be suppressed. Therefore, compared to when the second inert gas GA2 is not supplied, the processing liquid LQ having a lower dissolved oxygen concentration is introduced from the outer tank 110 into the processing tank 105 by the processing liquid introduction part 125. As a result, it is possible to suppress "an increase in the dissolved oxygen concentration of the processing liquid LQ in the processing tank 105 due to the processing liquid LQ introduced from the outer tank 110." Therefore, the substrate W immersed in the processing liquid LQ can be more effectively processed by the processing liquid LQ. In other words, by supplying the second inert gas GA2 into the outer tank 110 in addition to supplying the first inert gas GA1 to the processing liquid LQ in the processing tank 105, the substrate W can be more effectively processed by the processing liquid LQ compared to when only the first inert gas GA1 is used. In this way, the effectiveness of the inert gas is increased, and the substrate W can be effectively processed.

[0040] Furthermore, according to this embodiment, by supplying the first inert gas GA1 (gas bubbles BB) to the processing liquid LQ, the processing liquid LQ that comes into 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 inside the recesses can be effectively replaced with fresh processing liquid LQ by the diffusion phenomenon. Therefore, the wall surfaces inside the recesses of the surface pattern can be effectively processed (etched) with the processing liquid LQ from shallow to deep positions.

[0041] Preferably, the second gas supply unit 210 is disposed inside the outer tank 110, and discharges the second inert gas GA2 downward from each of the second discharge holes H2. According to this preferred example, it is possible to effectively prevent oxygen from dissolving in the processing liquid LQ stored in the outer tank 110. This is because the second inert gas GA2 is discharged onto the liquid surface of the processing liquid LQ in the outer tank 110 and fills the outer tank 110. As an example, the second gas supply unit 210 is disposed above the processing liquid LQ in the outer tank 110. Note that "below" refers to, for example, the lower side in the vertical direction D (vertically downward).

[0042] Specifically, the second gas supply pipe 25 is disposed inside the outer tank 110, and discharges the second inert gas GA2 downward from each of the second discharge holes H2. In this case, for example, the second discharge holes H2 face downward in the vertical direction D. That is, the second discharge holes H2 are disposed at the bottom of the second gas supply pipe 25.

[0043] Furthermore, in this embodiment, the first lid 111 covers the upper opening 106a of the processing tank 105 and the second lid 112. Therefore, it is possible to more effectively prevent oxygen from dissolving in the processing liquid LQ in the processing tank 105 and the processing liquid LQ in the outer tank 110. Furthermore, by providing the second lid 112, it is possible to prevent the second inert gas GA2 from leaking out from the outer tank 110. As a result, it is possible to more effectively prevent oxygen from dissolving in the processing liquid LQ in the outer tank 110.

[0044] Furthermore, in this embodiment, the contact portion 52 of the first lid 111 is in contact with the processing liquid LQ from above the processing liquid LQ in the processing tank 105 while covering the liquid surface of the processing liquid LQ. Therefore, it is possible to prevent the processing liquid LQ in the processing tank 105 from being exposed to oxygen. As a result, it is possible to more effectively prevent oxygen from dissolving in the processing liquid LQ in the processing tank 105.

[0045] Next, the relationship between the dissolved oxygen concentration and the etching amount will be explained with reference to Fig. 2. Fig. 2 is a graph showing the relationship between the dissolved oxygen concentration in the processing liquid LQ and the etching amount. The horizontal axis represents the dissolved oxygen concentration (ppm) in the processing liquid LQ, and the vertical axis represents the etching amount of the substrate W.

[0046] FIG. 2 shows an example in which TMAH was used as the processing liquid LQ. The concentration of TMAH was 0.31%. The first inert gas GA1 was nitrogen. The second inert gas GA2 was not used. This is because the experimental system was simplified in this example, as the purpose was to verify the relationship between the dissolved oxygen concentration of the processing liquid LQ and the etching amount.

[0047] A polysilicon film (polysilicon layer) was formed on the substrate W. Figure 2 shows the etching amount of the polysilicon film when the substrate W was 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 the "etching amount of the substrate W."

[0048] 2, the lower the dissolved oxygen concentration of the processing liquid 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.

[0049] Next, the relationship between the flow rate of the first inert gas GA1 and the dissolved oxygen concentration will be described with reference to Fig. 3. Fig. 3 is a graph showing the relationship between the supply time of the first inert gas GA1 (bubbles BB) 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 (hours) of the first inert gas GA1, and the vertical axis represents the dissolved oxygen concentration (ppm) of the treatment liquid LQ.

[0050] FIG. 3 shows an example in which TMAH was used as the processing liquid LQ. The concentration of TMAH was 0.31%. The first inert gas GA1 was nitrogen. The second inert gas GA2 was not used. This is because the experimental system was simplified in this example, as the purpose was to verify the relationship between the flow rate of the inert gas and the dissolved oxygen concentration. In addition, the flow rate of the processing liquid LQ in the circulation pipe 141 (FIG. 1) by the pump 142 (FIG. 1) was 23 liters / minute.

[0051] Plot g1 shows the dissolved oxygen concentration when the flow rate of the first inert gas GA1 is 10 liters / minute. Plot g2 shows the dissolved oxygen concentration when the flow rate of the first inert gas GA1 is 20 liters / minute. Plot g3 shows the dissolved oxygen concentration when the flow rate of the first inert gas GA1 is 30 liters / minute. In this case, the flow rate of the first inert gas GA1 indicates the flow rate supplied to one first gas supply pipe 21.

[0052] As can be seen from plots g1 to g3, the dissolved oxygen concentration of the treatment liquid LQ became approximately constant in about one hour. Furthermore, in a state in which the dissolved oxygen concentration became approximately constant, the greater the flow rate of the first inert gas GA1, the lower the dissolved oxygen concentration of the treatment liquid LQ. In other words, in a state in which the dissolved oxygen concentration became approximately constant, the greater the number of bubbles BB supplied to the treatment liquid LQ, the lower the dissolved oxygen concentration of the treatment liquid LQ. This is because the greater the flow rate of the first inert gas GA1, the more bubbles BB are supplied to the treatment liquid LQ.

[0053] 2 and 3, the greater the flow rate of the first inert gas GA1, the lower the dissolved oxygen concentration, and therefore the greater the flow rate of the first inert gas GA1, the greater the etching amount (processing amount) of the substrate W. In other words, the greater the amount of bubbles BB supplied to the processing liquid LQ, the lower the dissolved oxygen concentration, and therefore the greater the amount of bubbles BB, the greater the etching amount (processing amount) of the substrate W.

[0054] Next, the processing tank 105, outer tank 110, and substrate holder 120 will be described with reference to Fig. 4. Figs. 4(a) and 4(b) are schematic perspective views of the substrate processing apparatus 100 before and after the substrates W are loaded into the processing tank 105. Note that in Fig. 4, 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 shown in Fig. 1 are omitted to avoid overly complicating the drawing. Figs. 4(a) and 4(b) also show an example in which one lot (e.g., 25 substrates W) of substrates W is processed in the processing tank 105.

[0055] As shown in FIG. 4(a), the processing tank 105 includes a pair of side walls 105a and 105b, a front wall 105c, and a rear wall 105d.

[0056] The pair of side walls 105a, 105b extend along a first direction D10. The pair of side walls 105a, 105b are arranged at an interval in a second direction D20. Each of the pair of side walls 105a, 105b has a substantially flat plate shape and is substantially parallel to the vertical direction D.

[0057] The front wall 105c and the rear wall 105d extend along the second direction D20. The front wall 105c and the rear wall 105d are spaced apart in the first direction D10. Each of the front wall 105c and the rear wall 105d has a substantially flat plate shape and is substantially parallel to the vertical direction D. The front wall 105c and the rear wall 105d are substantially perpendicular to the pair of side walls 105a, 105b.

[0058] The outer tank 110 surrounds the processing tank 105. Specifically, the outer tank 110 surrounds at least the upper peripheral surface of the processing tank 105. More specifically, the outer tank 110 includes a first reservoir 117a, a second reservoir 117b, a third reservoir 117c, and a fourth reservoir 117d. The first to fourth reservoirs 117a to 117d store the processing liquid LQ that overflows from the processing tank 105.

[0059] First reservoir 117a extends along sidewall 105a. First reservoir 117a extends in first direction D10. First reservoir 117a is disposed on the outer side of the upper portion of sidewall 105a.

[0060] Second reservoir 117b extends along sidewall 105b. Second reservoir 117b is disposed on the outer side of the upper portion of sidewall 105b. Second reservoir 117b extends along first direction D10.

[0061] Third reservoir 117c extends along front wall 105c. Third reservoir 117c extends along second direction D20. Third reservoir 117c is disposed outside front wall 105c. Third reservoir 117c extends from the top to the bottom of front wall 105c.

[0062] Fourth reservoir 117d extends along rear wall 105d. Fourth reservoir 117d is disposed on the upper outer side of rear wall 105d. Fourth reservoir 117d extends along second direction D20.

[0063] The substrate holding unit 120 holds a plurality of substrates W along a first direction D10. Specifically, the substrate holding unit 120 holds a plurality of substrates W (one lot of substrates W) spaced apart in the first direction D10. The plurality of 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 plurality of substrates W. The first direction D10 is approximately parallel to the horizontal direction and approximately perpendicular to the vertical direction D. Furthermore, each of the plurality of substrates W is approximately parallel to a second direction D20. The second direction D20 is approximately perpendicular to the first direction D10 and the vertical direction D, and is approximately parallel to the horizontal direction.

[0064] The first direction D10 corresponds to an example of the "predetermined direction" of the present invention.

[0065] In FIG. 4(a), the substrate holding part 120 is positioned above the processing tank 105. The substrate holding part 120 descends in the vertical direction D while holding a plurality of substrates W. As a result, the plurality of substrates W are placed into the processing tank 105. As shown in FIG. 4(b), when the substrate holding part 120 descends to the processing tank 105, the plurality of substrates W are immersed in the processing liquid LQ in the processing tank 105.

[0066] Next, the second gas supply unit 210 (FIG. 1) will be described with reference to FIGS. 5 and 6. FIG. 5 is a schematic plan view showing the substrate processing apparatus 100 when the first lid 111 and the second lid 112 (FIG. 1) are removed. In FIG. 5, no substrate W has been placed in the processing tank 105.

[0067] 5, the second gas supply unit 210 includes a second gas supply pipe 25 and a valve 26. The second gas supply pipe 25 is disposed inside the outer tank 110. The second gas supply pipe 25 surrounds the processing tank 105. Specifically, the second gas supply pipe 25 includes a first pipe section 25a, a second pipe section 25b, a third pipe section 25c, a fourth pipe section 25d, a fifth pipe section 25e, and a sixth pipe section 25f.

[0068] The first piping section 25a is disposed inside the third storage section 117c. Specifically, the first piping section 25a is disposed in an upper region inside the third storage section 117c. 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.

[0069] Second piping section 25b is disposed inside third storage section 117c. Specifically, second piping section 25b is disposed in an upper region inside third storage section 117c. Second piping section 25b bends from the downstream end of first piping section 25a and extends along front wall 105c. Second piping section 25b extends along second direction D20.

[0070] Third piping section 25c is disposed inside first storage section 117a. Specifically, third piping section 25c is disposed in an upper region inside first storage section 117a. Third piping section 25c bends from the downstream end of second piping section 25b and extends along sidewall 105a. Third piping section 25c extends along first direction D10.

[0071] Fourth piping section 25d is disposed inside fourth storage section 117d. Specifically, fourth piping section 25d is disposed in an upper region inside fourth storage section 117d. Fourth piping section 25d bends from the downstream end of third piping section 25c and extends along rear wall 105d. Fourth piping section 25d extends along second direction D20.

[0072] Fifth piping section 25e is disposed inside second storage section 117b. Specifically, fifth piping section 25e is disposed in an upper region inside second storage section 117b. Fifth piping section 25e bends from the downstream end of fourth piping section 25d and extends along sidewall 105b. Fifth piping section 25e extends along first direction D10.

[0073] The sixth piping section 25f is disposed inside the third storage section 117c. Specifically, the sixth piping section 25f is disposed in an upper region inside the third storage section 117c. The sixth piping section 25f bends from the downstream end of the fifth piping section 25e and extends along the front wall 105c. The sixth piping section 25f extends along the second direction D20. The downstream end of the sixth piping section 25f is closed.

[0074] A plurality of second discharge holes H2 (FIG. 1) are provided in each of first piping section 25a to sixth piping section 25f. Therefore, in any of first reservoir 117a to fourth reservoir 117d, it is possible to prevent oxygen from dissolving in the treatment liquid LQ.

[0075] The substrate processing apparatus 100 further includes a pipe 185. The pipe 185 connects the second gas supply pipe 25 (specifically, the first pipe section 25a) and an inert gas supply source TKC via a valve 26. The inert gas supply source TKC stores inert gases. The inert gases are a first inert gas GA1 and a second inert gas GA2. This is because, in this embodiment, the first inert gas GA1 and the second inert gas GA2 are the same inert gas.

[0076] The inert gas supply source TKC supplies the second inert gas GA2 to the second gas supply pipe 25 via the valve 26 and the pipe 185.

[0077] Specifically, the valve 26 is disposed on the pipe 185 outside the processing tank 105 and the outer tank 110. The valve 26 opens the flow path of the pipe 185 to supply the second inert gas GA2 from the inert gas supply source TKC to the second gas supply pipe 25. On the other hand, the valve 26 closes the flow path of the pipe 185 to stop the supply of the second inert gas GA2 from the inert gas supply source TKC to the second gas supply pipe 25.

[0078] Fig. 6 is a cross-sectional view taken along line VI-VI in Fig. 5. As shown in Fig. 6, the second gas supply pipe 25 is disposed above the processing liquid LQ in the outer bath 110. In the second gas supply pipe 25, a plurality of second discharge holes H2 are disposed in a substantially straight line at intervals in the first direction D10. The plurality of second discharge holes H2 open downward in the vertical direction D and face the liquid surface of the processing liquid LQ in the vertical direction D. The second gas supply pipe 25 discharges a second inert gas GA2 from the plurality of second discharge holes H2 toward the liquid surface of the processing liquid LQ in the outer bath 110.

[0079] Next, the second lid 112 will be described with reference to Fig. 7. Fig. 7 is a schematic plan view showing the substrate processing apparatus 100 when the first lid 111 (Fig. 1) is removed. In Fig. 7, no substrate W has been placed in the processing bath 105.

[0080] 7, the second lid 112 covers the upper opening 110a of the outer tank 110. The second lid 112 has an opening 112a. The opening 112a has a substantially rectangular shape. An edge 112b of the opening 112a extends along the upper edge 105u of the treatment tank 105, on the inside of the upper edge 105u of the treatment tank 105.

[0081] The second cover 112 has a processing liquid hole 112c and a diluent liquid hole 112d. The substrate processing apparatus 100 further includes a processing liquid supply unit 150 and a diluent liquid supply unit 160.

[0082] The processing liquid supply unit 150, under the control of the control unit 221 (FIG. 1), supplies the processing liquid LQ from the processing liquid hole 112c to the outer bath 110. The processing liquid supply unit 150 supplies the processing liquid LQ to the outer bath 110, for example, after cleaning the processing bath 105 and the outer bath 110, or when replacing the processing liquid LQ.

[0083] Specifically, the processing liquid supply unit 150 includes a pipe 154 and a valve 156. The processing liquid LQ is supplied to the pipe 154 from a processing liquid supply source TKA. The valve 156 is disposed in the pipe 154. When the valve 156 is opened, the processing liquid LQ is supplied from the pipe 154 through the processing liquid hole 112c into the outer bath 110. Then, the processing liquid LQ is supplied from the outer bath 110 to the processing bath 105 by the processing liquid introduction unit 125 (FIG. 1). The processing liquid LQ may also be supplied directly to the processing bath 105.

[0084] The diluent supply unit 160 is controlled by the control unit 221 (FIG. 1) and supplies the diluent to the outer tank 110. Specifically, the diluent supply unit 160 includes a pipe 164 and a valve 166. The diluent is supplied to the pipe 164 from a diluent supply source TKB. The valve 166 is disposed on the pipe 164. When the valve 166 is opened, the diluent is supplied from the pipe 164 into the outer tank 110 through the diluent hole 112d.

[0085] Next, the first lid 111 will be described with reference to FIGS. 8 and 9. FIG. 8 is a schematic plan view showing the first lid 111. As shown in FIG. 8, the separation portion 51 of the first lid 111 has an opening 51c. The opening 51c has a substantially rectangular shape. The opening 51c extends along the second direction D20. The opening 51c overlaps with a portion 112x (FIG. 7) of the opening 112a of the second lid 112 in the vertical direction D. The main body plate 122 of the substrate holder 120 (FIG. 4) is inserted into the opening 51c.

[0086] In the first cover 111, the separation portion 51 includes a first separation portion 51a and a second separation portion 51b. Each of the first separation portion 51a and the second separation portion 51b has a substantially flat plate shape. In addition, the contact portion 52 includes a first contact portion 52a and a second contact portion 52b. Each of the first contact portion 52a and the second contact portion 52b has a substantially flat plate shape.

[0087] The first separating portion 51a and the first contact portion 52a constitute the first hinged door portion 50a. The first separating portion 51a and the first contact portion 52a may be integrally molded or may be separate members. When the first separating portion 51a and the first contact portion 52a are separate members, the first separating portion 51a and the first contact portion 52a are connected to each other.

[0088] The second separating portion 51b and the second contact portion 52b constitute the second hinged door portion 50b. The second separating portion 51b and the second contact portion 52b may be integrally molded or may be separate members. When the second separating portion 51b and the second contact portion 52b are separate members, the second separating portion 51b and the second contact portion 52b are connected to each other.

[0089] The first lid 111 further includes a first support portion 53a and a second support portion 53b. The substrate processing apparatus 100 also includes a first drive mechanism 60a and a second drive mechanism 60b. The first drive mechanism 60a includes a first rotation shaft 61a, a first connection portion 62a, and a first drive portion 63a. The second drive mechanism 60b includes a second rotation shaft 61b, a second connection portion 62b, and a second drive portion 63b.

[0090] The first support portion 53a supports the first hinged door portion 50a. The first drive mechanism 60a is connected to the first support portion 53a. The first drive mechanism 60a drives and rotates the first hinged door portion 50a via the first support portion 53a, thereby opening and closing the first hinged door portion 50a relative to the upper opening 106a (FIG. 1) of the treatment tank 105.

[0091] Specifically, the first support portion 53a is connected to one end of the first separation portion 51a in the first direction D10 on one side of the first cover body 111 in the second direction D20. The first support portion 53a extends along the first direction D10. A first rotation shaft 61a is connected to the first support portion 53a. The first rotation shaft 61a extends along the first direction D10. The first connection portion 62a is a connection mechanism that connects the first rotation shaft 61a to the first drive portion 63a. The first drive portion 63a rotates the first rotation shaft 61a via the first connection portion 62a. As a result, the first support portion 53a rotates, and the first hinged door portion 50a supported by the first support portion 53a rotates. In this way, the first drive portion 63a drives the first hinged door portion 50a to rotate around the first rotation shaft 61a. The first driving unit 63a includes, for example, a motor or an air cylinder.

[0092] The second support portion 53b supports the second hinged door portion 50b. The second drive mechanism 60b is connected to the second support portion 53b. The second drive mechanism 60b rotates the second hinged door portion 50b via the second support portion 53b, thereby opening and closing the second hinged door portion 50b relative to the upper opening 106a (FIG. 1) of the treatment tank 105.

[0093] Specifically, the second support portion 53b is connected to one end of the second separation portion 51b in the first direction D10 on the other side of the first cover body 111 in the second direction D20. The second support portion 53b extends along the first direction D10. A second rotation shaft 61b is connected to the second support portion 53b. The second rotation shaft 61b extends along the first direction D10. The second connection portion 62b is a connection mechanism that connects the second rotation shaft 61b to the second drive portion 63b. The second drive portion 63b rotates the second rotation shaft 61b via the second connection portion 62b. As a result, the second support portion 53b rotates, and the second hinged door portion 50b supported by the second support portion 53b rotates. In this way, the second drive portion 63b drives the second hinged door portion 50b to rotate around the second rotation shaft 61b. The second driving unit 63b includes, for example, a motor or an air cylinder.

[0094] Fig. 9(a) is a schematic diagram showing a state in which the first lid body 111 is closed. Fig. 9(b) is a schematic diagram showing a state in which the first lid body 111 is open. In Fig. 9(a) and Fig. 9(b), the first lid body 111 is viewed from direction DA in Fig. 8.

[0095] As shown in FIG. 9(a), the first hinged door portion 50a and the second hinged door portion 50b are closed, and the first lid body 111 is closed.

[0096] When the first lid 111 is closed, the first hinged door portion 50a covers one side of the upper opening 106a of the treatment tank 105 in the second direction D20. Therefore, the first contact portion 52a contacts one side of the liquid surface of the treatment liquid LQ in the second direction D20. In the example of FIG. 9(a), the lower portion of the first contact portion 52a is submerged in one side of the liquid surface of the treatment liquid LQ in the second direction D20.

[0097] When the first lid 111 is closed, the second hinged door portion 50b covers the other side of the upper opening 106a of the treatment tank 105 in the second direction D20. Therefore, the second contact portion 52b contacts the other side of the liquid surface of the treatment liquid LQ in the second direction D20. In the example of FIG. 9(a), the lower portion of the second contact portion 52b is submerged in the other side of the liquid surface of the treatment liquid LQ in the second direction D20.

[0098] When the first swing door section 50a and the second swing door section 50b are closed, an end face 54a of the first swing door section 50a and an end face 54b of the second swing door section 50b come into contact with each other. Furthermore, when the first swing door section 50a and the second swing door section 50b are closed, the first rotating shaft 61a and the second rotating shaft 61b are positioned below the area Za of the first swing door section 50a and the area Zb of the second swing door section 50b. As a result, interference between the first swing door section 50a and the second swing door section 50b is prevented, allowing the first swing door section 50a and the second swing door section 50b to be opened and closed smoothly.

[0099] The portion Za is the lower end of the first contact portion 52a at the center in the second direction D20 of the contact portion 52 when the first swing door portion 50a and the second swing door portion 50b are closed. The portion Zb is the lower end of the second contact portion 52b at the center in the second direction D20 of the contact portion 52 when the first swing door portion 50a and the second swing door portion 50b are closed.

[0100] 9(b), when the first rotating shaft 61a rotates counterclockwise, the first hinged door portion 50a opens one side of the upper opening 106a of the treatment tank 105 in the second direction D20. On the other hand, when the first rotating shaft 61a rotates clockwise, the first hinged door portion 50a covers one side of the upper opening 106a of the treatment tank 105 in the second direction D20.

[0101] When the second rotating shaft 61b rotates clockwise, the second hinged door portion 50b opens the other side of the upper opening 106a of the treatment tank 105 in the second direction D20. On the other hand, when the second rotating shaft 61b rotates counterclockwise, the second hinged door portion 50b covers the other side of the upper opening 106a of the treatment tank 105 in the second direction D20.

[0102] Returning to FIG. 1 , other configuration details of the substrate processing apparatus 100 will be described. The substrate holding unit 120 moves up and down in the vertical direction D while holding multiple substrates W. Specifically, the substrate holding unit 120 includes a main body plate 122 and multiple holding rods 124. The main body plate 122 is a plate extending in the vertical direction D. The multiple holding rods 124 extend from the main body plate 122 in a first direction D10 ( FIG. 4 ). The multiple substrates W are aligned at intervals and are held in an upright position (vertical position) by the multiple holding rods 124 abutting the lower edge of each substrate W.

[0103] The substrate holding part 120 may further include a lifting unit 126. The lifting unit 126 raises and lowers the main body plate 122 between a processing position (position shown in FIG. 4(b)) where the plurality of substrates W held by the substrate holding part 120 are located in the processing bath 105, and a retracted position (position shown in FIG. 4(a)) where the plurality of substrates W held by the substrate holding part 120 are located above the processing bath 105. Therefore, when the main body plate 122 is moved to the processing position by the lifting unit 126, the plurality of substrates W held by the holding rods 124 are immersed in the processing liquid LQ. In this way, the plurality of substrates W are subjected to processing.

[0104] The treatment liquid introduction section 125 includes an introduction section 130 and a circulation section 140 .

[0105] The introduction part 130 introduces the processing liquid LQ into the processing tank 105. The introduction part 130 is disposed inside the processing tank 105 below the first gas supply part 200 (specifically, the first gas supply pipe 21).

[0106] Specifically, the introduction unit 130 includes a plate 31. The plate 31 has a substantially flat plate shape. The plate 31 divides the interior of the processing tank 105 to form a processing chamber 113 and an introduction chamber 115. That is, the processing tank 105 has the processing chamber 113 and the introduction chamber 115. The processing chamber 113 is a chamber located above the plate 31 within the processing tank 105. The first gas supply unit 200 is disposed in the processing chamber 113. The substrate W is disposed in the processing chamber 113. The introduction chamber 115 is a chamber located below the plate 31 within the processing tank 105.

[0107] The plate 31 is disposed 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 disposed over the entire surface of the plate 31. The processing liquid holes P face upward in the vertical direction D.

[0108] The plurality of first gas supply pipes 21 are arranged inside the processing tank 105 above the plate 31 and below the substrate W.

[0109] The introduction unit 130 introduces the processing liquid LQ upward from the multiple processing liquid holes P into the processing tank 105 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 upward from the multiple processing liquid holes P in a substantially vertical direction D.

[0110] According to this embodiment, the processing liquid LQ is introduced into the processing tank 105 by a laminar flow of the processing liquid LQ, and therefore, it is possible to prevent the flow of the bubbles BB supplied to the processing liquid LQ by the first gas supply unit 200 from being disturbed. Therefore, the bubbles BB can effectively reduce the dissolved oxygen concentration in the processing liquid LQ. As a result, the substrate W can be effectively processed (e.g., etched) by the processing liquid LQ.

[0111] 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 pipe. 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 disposed in the introduction chamber 115.

[0112] The discharge unit 131 is located below the dispersion plate 132. The discharge unit 131 faces the dispersion plate 132 in the vertical direction D. The discharge unit 131 discharges the treatment liquid LQ supplied from the circulation unit 140 toward the dispersion plate 132. Therefore, the treatment liquid LQ hits the dispersion plate 132. As a result, the pressure of the treatment liquid LQ is dispersed by the dispersion plate 132. In other words, the dispersion plate 132 distributes the pressure of the treatment liquid LQ discharged by the discharge unit 131. Then, the treatment liquid LQ, whose pressure has been dispersed by the dispersion plate 132, spreads in a substantially horizontal direction in the introduction chamber 115. Furthermore, the treatment liquid LQ is supplied as a laminar flow upward along the vertical direction D from each treatment liquid hole P of the plate 31 into the treatment chamber 113. In this way, the introduction unit 130 has a function of rectifying the treatment liquid LQ in that it generates a laminar flow of the treatment liquid LQ along the vertical direction D.

[0113] The circulation section 140 circulates the processing liquid LQ in the processing tank 105 by supplying the processing liquid LQ that has overflowed from the processing tank 105 and flowed into the outer tank 110 to the introduction section 130 .

[0114] Specifically, the circulation unit 140 includes a circulation pipe 141, a pump 142, a heater 143, a filter 144, an adjustment valve 145, and a valve 146. The pump 142, the heater 143, the filter 144, the adjustment valve 145, and the valve 146 are arranged in this order from the upstream to the downstream of the circulation pipe 141.

[0115] The circulation pipe 141 connects the outer bath 110 and the processing bath 105. The circulation pipe 141 guides the processing liquid LQ that has overflowed from the processing bath 105 and flowed into the outer bath 110 back to the processing bath 105. In this manner, the processing liquid LQ flows through the circulation pipe 141. Specifically, the upstream end of the circulation pipe 141 is connected to the outer bath 110. On the other hand, the introduction part 130 (specifically, the discharge part 131) is connected to the downstream end of the circulation pipe 141. Therefore, the circulation pipe 141 guides the processing liquid LQ from the outer bath 110 to the introduction part 130 (specifically, the discharge part 131).

[0116] The pump 142 sends out the processing liquid LQ from the outer bath 110 toward the processing bath 105 via the circulation pipe 141. Specifically, the pump 142 sends out the processing liquid LQ in the outer bath 110 from the circulation pipe 141 toward the discharge unit 131. Therefore, the discharge unit 131 discharges the processing liquid LQ supplied from the circulation pipe 141. The filter 144 filters the processing liquid LQ flowing through the circulation pipe 141. The greater the flow rate of the processing liquid LQ, the greater the filtering effect of the filter 144.

[0117] The heater 143 heats the processing liquid LQ flowing through the circulation pipe 141. That is, the heater 143 adjusts the temperature of the processing liquid LQ. The adjustment valve 145 adjusts the opening of the circulation pipe 141 to adjust the flow rate of the processing liquid LQ supplied to the discharge part 131. Specifically, the adjustment valve 145 finely adjusts the flow rate of the processing liquid LQ flowing through the circulation pipe 141. This is because the flow rate of the processing liquid LQ flowing through the circulation pipe 141 is basically set by the pump 142. The valve 146 opens and closes the circulation pipe 141.

[0118] The drainage unit 170 includes a drainage pipe 170a and a valve 170b. The drainage pipe 170a is connected to the bottom wall of the processing tank 105. A valve 170b is disposed in the drainage pipe 170a. When the valve 170b opens, the processing liquid LQ stored in the processing tank 105 is discharged to the outside through the drainage pipe 170a. The discharged processing liquid LQ is sent to a wastewater treatment device (not shown) and treated.

[0119] The gas flow rate adjuster 180 supplies the first inert gas GA1 supplied from the inert gas supply source TKC to the plurality of first gas supply pipes 21. Specifically, the substrate processing apparatus 100 further includes a plurality of pipes 181. The plurality of pipes 181 are connected to the plurality of first gas supply pipes 21, respectively. The gas flow rate adjuster 180 supplies the first inert gas GA1 supplied from the inert gas supply source TKC from the plurality of pipes 181 to the plurality of first gas supply pipes 21, respectively.

[0120] Specifically, the gas flow rate adjusting unit 180 includes a plurality of gas flow rate adjusting mechanisms 182. The plurality of gas flow rate adjusting mechanisms 182 are connected to a plurality of pipes 181, respectively. 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 adjusting mechanism 182. The plurality of gas flow rate adjusting mechanisms 182 are provided corresponding to the plurality of first gas supply pipes 21, respectively. The gas flow rate adjusting mechanisms 182 supply the first inert gas GA1, which is supplied from the inert gas supply source TKC, to the corresponding first gas supply pipe 21 via the corresponding pipe 181. Furthermore, the gas flow rate adjusting mechanism 182 adjusts the flow rate of the first inert gas GA1 supplied to the corresponding first gas supply pipe 21.

[0121] Next, the first gas supply unit 200 will be described with reference to Fig. 10. Fig. 10 is a schematic plan view showing the first gas supply unit 200. As shown in Fig. 10, 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 Fig. 10, the multiple first gas supply pipes 21 are arranged symmetrically with respect to an imaginary center line CL. The imaginary center line CL passes through the center of each substrate W and extends along a first direction D10.

[0122] Specifically, the multiple first gas supply pipes 21 are arranged in the processing tank 105 substantially parallel to one another 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 at intervals in the first direction D10. In each of the multiple first gas supply pipes 21, the first discharge holes H1 are provided in an upper portion of the first gas supply pipe 21.

[0123] Each of the plurality of gas flow rate adjustment mechanisms 182 includes a valve 41, a filter 42, a flow meter 43, and an adjustment valve 44. The valve 41, the filter 42, the flow meter 43, and the adjustment valve 44 are arranged in this order on the pipe 181 from downstream to upstream of the pipe 181.

[0124] The adjustment valve 44 adjusts the flow rate of the first inert gas GA1 supplied to the pipe 181 by adjusting the opening of the pipe 181, 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 pipe 181. The adjustment valve 44 adjusts the flow rate of the first inert gas GA1 based on the measurement result of the flow meter 43. Note that, for example, a mass flow controller may be provided instead of the adjustment valve 44 and the flow meter 43.

[0125] The filter 42 removes foreign matter from the first inert gas GA1 flowing through the pipe 181. The valve 41 opens and closes the pipe 181. That is, the valve 41 switches between supplying and stopping the supply of the first inert gas GA1 from the pipe 181 to the first gas supply pipe 21.

[0126] Next, the introduction section 130 will be described with reference to FIG. 11. FIG. 11 is a schematic rear view showing the introduction section 130. As shown in FIG. 11, the introduction section 130 includes a plurality of discharge sections 131 and a plurality of dispersion plates 132. In the example of FIG. 11, 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. The plurality of dispersion plates 132 correspond to the plurality of discharge sections 131, respectively. The plurality of dispersion plates 132 are arranged below the plate 31. In the example of FIG. 11, the dispersion plate 132 has a substantially circular plate shape. The plurality of discharge sections 131 are arranged below the plurality of dispersion plates 132, respectively.

[0127] The discharge portion 131 and the dispersion plate 132 are disposed 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.

[0128] The circulation pipe 141 (FIG. 1) includes a pipe 133. The pipe 133 extends from one end side to the other end side in the first direction D10 of the plate 31. The pipe 133 extends along the first direction D10. The pipe 133 faces the back surface of the plate 31. In other words, the pipe 133 is disposed below the plate 31. Specifically, the pipe 133 is disposed below the dispersion plate 132.

[0129] The discharge part 131 is connected to the upper surface of the pipe 133. The discharge part 131 and the pipe 133 are in communication with each other. The discharge part 131 protrudes vertically upward from the pipe 133 toward the dispersion plate 132. The treatment liquid LQ is supplied to the pipe 133 from the circulation part 140 (FIG. 1). As a result, the discharge part 131 discharges the treatment liquid LQ toward the dispersion plate 132. This distributes the pressure of the treatment liquid LQ, causing the treatment liquid LQ to spread in the horizontal direction. The treatment liquid LQ then rises from the multiple treatment liquid holes P, forming a laminar flow.

[0130] Referring again to FIG. 1 , the relationship between the dissolved oxygen concentration of the processing liquid LQ and the pump flow rate and inert gas flow rate will be described. In this specification, the pump flow rate refers to the flow rate of the processing liquid LQ sent out by the pump 142 in the circulation pipe 141. In this embodiment, the pump flow rate is essentially synonymous with the "flow rate of the processing liquid LQ flowing through the circulation pipe 141." The pump flow rate indicates the flow rate of the processing liquid LQ per unit time. The inert gas flow rate refers to the flow rate of the first inert gas GA1 supplied to the first gas supply pipe 21 to generate the bubbles BB. The inert gas flow rate is indicated by the flow rate of the first inert gas GA1 supplied to one first gas supply pipe 21. The inert gas flow rate indicates the flow rate of the first inert gas GA1 per unit time. This also applies to the second inert gas GA2.

[0131] The dissolved oxygen concentration of the treatment liquid LQ in the treatment tank 105 has the following characteristics (1) to (3).

[0132] (1) When the first inert gas GA1 (gas bubbles BB) is not supplied to the processing liquid LQ in the processing tank 105, the dissolved oxygen concentration of the processing liquid LQ increases over time. In this case, the smaller the pump flow rate, the slower the rate of increase in the dissolved oxygen concentration of the processing liquid LQ. The characteristic (1) is demonstrated by Example 1 (FIG. 20), which will be described later.

[0133] (2) When the first inert gas GA1 (gas bubbles BB) is supplied to the processing liquid LQ in the processing tank 105, the dissolved oxygen concentration of the processing liquid LQ decreases over time and converges to a substantially constant value. In this case, the smaller the pump flow rate, the smaller the dissolved oxygen concentration of the processing liquid LQ. Furthermore, the smaller the pump flow rate, the faster the rate at which the dissolved oxygen concentration of the processing liquid LQ decreases. Property (2) is demonstrated by Example 2 (FIG. 21), which will be described later.

[0134] (3) When the first inert gas GA1 (gas bubbles BB) is supplied to the processing liquid LQ in the processing tank 105, the dissolved oxygen concentration of the processing liquid LQ decreases over time and converges to a substantially constant value. In this case, the greater the inert gas flow rate, the smaller the dissolved oxygen concentration of the processing liquid LQ. Furthermore, the greater the inert gas flow rate, the faster the rate at which the dissolved oxygen concentration of the processing liquid LQ decreases. Property (3) is demonstrated by Example 3 (FIG. 22), which will be described later.

[0135] In the present embodiment, as a preferred example, the control unit 221 executes control based on the above-described characteristics (1) to (3) of the dissolved oxygen concentration. In this case, as shown in FIG. 1, 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 storage device of the storage unit 223, thereby functioning as the first control unit A1 to the third control unit A3. The first control unit A1 controls the gas flow rate regulator 180. The second control unit A2 controls the pump 142. The third control unit A3 controls the second gas supply unit 210 (specifically, the valve 26).

[0136] Fig. 12 is a diagram showing the control of the dissolved oxygen concentration of the processing liquid LQ in the processing tank 105. In Fig. 12, the horizontal axis represents time, and the vertical axis represents the dissolved oxygen concentration of the processing liquid LQ.

[0137] 12, at time t1, the processing liquid supply unit 150 (FIG. 7) starts supplying the processing liquid LQ to the empty processing tank 105 via the outer tank 110. Then, when a predetermined amount of the processing liquid LQ has been supplied, the processing liquid supply unit 150 stops supplying the processing liquid LQ.

[0138] The period from time t1 to time t2 is a period T1 before the processing of the substrate W (period T1 before the substrate W is immersed in the processing liquid LQ). In period T1, the flow rate of the first inert gas GA1 is "Ga (liters / minute)". In period T1, the flow rate of the second inert gas GA2 is "Gc (liters / minute)". In period T1, the pump flow rate (the flow rate of the processing liquid LQ delivered by the pump 142) is "Pa (liters / minute)". The flow rate Ga of the first inert gas GA1 in the period T1 before processing is greater than the flow rate Gb of the first inert gas GA1 in the pre-processing period T2 and the processing period T3.

[0139] The period from time t2 to time t3 is a pre-treatment period T2. The pre-treatment is a treatment (preparatory treatment) performed for a certain period immediately before the substrate W is immersed in the treatment liquid LQ. During the pre-treatment period T2, the substrate holder 120 immerses the substrate W in the treatment liquid LQ.

[0140] The period from time t3 to time t4 is period T3 during which the substrate W is processed (period T3 during which the substrate W is immersed in the processing liquid LQ). Then, near the end of period T3, the substrate holder 120 lifts the substrate W out of the processing liquid LQ. The lifting of the substrate W is completed by time t4.

[0141] During periods T2 and T3, the flow rate of the first inert gas GA1 is "Gb (liters / minute)". During periods T2 and T3, the flow rate of the second inert gas GA2 is "Gc (liters / minute)". During periods T2 and T3, the pump flow rate is "Pb (liters / minute)".

[0142] The flow rate Gb of the first inert gas GA1 during the pre-processing period T2 and the processing period T3 is smaller than the flow rate Ga during the pre-processing period T1, the post-processing period T4, and the post-processing period T5. The pump flow rate Pb during the pre-processing period T2 and the processing period T3 is smaller than the pump flow rate Pa during the pre-processing period T1, the post-processing period T4, and the post-processing period T5. Preferably, the pump flow rate Pb during the pre-processing period T2 and the processing period T3 is zero.

[0143] The period from time t4 to time t5 is a post-processing period T4. The post-processing is a processing period that occurs immediately after the substrate W is lifted up from the processing liquid LQ.

[0144] The period from time t5 onwards is a period T5 after processing of the substrates W (period T5 after the substrates W are pulled up from the processing liquid LQ). In other words, period T5 is a waiting period for processing the substrates W of the next lot.

[0145] During periods T4 and T5, the flow rate of the first inert gas GA1 is "Ga (liters / minute)". During periods T4 and T5, the flow rate of the second inert gas GA2 is "Gc (liters / minute)". During periods T4 and T5, the pump flow rate is "Pa (liters / minute)". The flow rate Ga of the first inert gas GA1 during the post-processing period T4 and the post-processing period T5 is greater than the flow rate Gb of the first inert gas GA1 during the pre-processing period T2 and the processing period T3.

[0146] 12, in this embodiment, the flow rate Ga of the first inert gas GA1 during the periods T1, T4, and T5 when the substrate W is not immersed in the processing liquid LQ is greater than the flow rate Gb of the first inert gas GA1 during the period T3 when the substrate W is immersed in the processing liquid LQ. In other words, the first control unit A1 controls the gas flow rate adjuster 180 so that the flow rate Ga of the first inert gas GA1 during the periods T1, T4, and T5 when the substrate W is not immersed in the processing liquid LQ is greater than the flow rate Gb of the first inert gas GA1 during the period T3 when the substrate W is immersed in the processing liquid LQ.

[0147] As a result, particularly during the period T1, the dissolved oxygen concentration of the processing liquid LQ in the processing tank 105 can be reduced rapidly (characteristic (3) of dissolved oxygen concentration), thereby shortening the period until the start of processing of the substrate W. Furthermore, by increasing the flow rate Ga of the first inert gas GA1, it is possible to effectively prevent oxygen from dissolving in the processing liquid LQ in the processing tank 105 not only during the period T1 but also during the periods T4 and T5. Furthermore, since the substrate W is not immersed in the processing liquid LQ during the periods T1, T4, and T5, even if the flow rate Ga of the first inert gas GA1 is increased, the substrate W will not be displaced due to the bubbles BB of the first inert gas GA1.

[0148] Furthermore, the first control unit A1 may control the gas flow rate adjuster 180 so that the flow rate Ga of the first inert gas GA1 becomes the maximum flow rate during periods T1, T4, and T5 when the substrate W is not immersed in the processing liquid LQ. In this case, the dissolved oxygen concentration of the processing liquid LQ in the processing tank 105 can be reduced more rapidly, particularly during period T1, thereby further shortening the time until processing of the substrate W begins. Furthermore, dissolution of oxygen in the processing liquid LQ in the processing tank 105 can be more effectively suppressed not only during period T1 but also during periods T4 and T5. Here, the maximum flow rate refers to the maximum flow rate of the first inert gas GA1 that can be supplied by the gas flow rate adjuster 180.

[0149] Furthermore, in this embodiment, the pump flow rate Pb during the period T3 when the substrate W is immersed in the processing liquid LQ is smaller than the pump flow rate Pa during the periods T1, T4, and T5 when the substrate W is not immersed in the processing liquid LQ. In other words, the second control unit A2 controls the pump 142 so that the flow rate Pb of the processing liquid LQ flowing through the circulation piping 141 during the period T3 when the substrate W is immersed in the processing liquid LQ is smaller than the flow rate Pa of the processing liquid LQ flowing through the circulation piping 141 during the periods T1, T4, and T5 when the substrate W is not immersed in the processing liquid LQ.

[0150] As a result, during the period T3, the dissolved oxygen concentration of the processing liquid LQ in the processing tank 105 can be effectively reduced (characteristic (2) of dissolved oxygen concentration), and therefore the processing amount of substrates W can be increased. This improves the throughput when processing substrates W. Note that during the period T3, the dissolved oxygen concentration of the processing liquid LQ is lower than during the periods T1 and T5.

[0151] More preferably, the second control unit A2 stops the pump 142 during the period T3 during which the substrate W is immersed in the processing liquid LQ. As a result, during the period T3, the dissolved oxygen concentration of the processing liquid LQ in the processing tank 105 can be more effectively reduced (characteristic (2) of dissolved oxygen concentration). The fact that the pump 142 is stopped indicates that the flow rate of the processing liquid LQ in the circulation pipe 141 is zero.

[0152] Furthermore, in this embodiment, the pump flow rate Pa during periods T1, T4, and T5 when the substrate W is not immersed in the processing liquid LQ is greater than the pump flow rate Pb during period T3 when the substrate W is immersed in the processing liquid LQ. In other words, the second control unit A2 controls the pump 142 so that the flow rate Pa of the processing liquid LQ flowing through the circulation pipe 141 during periods T1, T4, and T5 when the substrate W is not immersed in the processing liquid LQ is greater than the flow rate Pb during period T3 when the substrate W is immersed in the processing liquid LQ. As a result, the filtering effect of the filter 144 can be improved during periods T1, T4, and T5.

[0153] Furthermore, the pump flow rate Pa may be the maximum flow rate during periods T1, T4, and T5 when the substrate W is not immersed in the processing liquid LQ. In other words, the second control unit A2 may control the pump 142 so that the flow rate Pa of the processing liquid LQ flowing through the circulation pipe 141 becomes the maximum flow rate during periods T1, T4, and T5 when the substrate W is not immersed in the processing liquid LQ. In this case, the filtering effect of the filter 144 can be further improved during periods T1, T4, and T5. Here, the maximum flow rate refers to the maximum flow rate of the processing liquid LQ that can be delivered by the pump 142.

[0154] In addition, when prioritizing reducing the dissolved oxygen concentration of the processing liquid LQ over filtering by the filter 144, the second control unit A2 sets the flow rate Pa of the processing liquid LQ during periods T1, T4, and T5 to be greater than the flow rate Pb of the processing liquid LQ during period T3 and smaller than the maximum flow rate of the processing liquid LQ by the pump 142.

[0155] Furthermore, in this embodiment, the first controller A1 controls the gas flow rate adjuster 180 so that the flow rate Gb of the first inert gas GA1 during the pre-processing period T2 is smaller than the flow rate Ga of the first inert gas GA1 during the periods T1, T4, and T5 when the substrate W is not immersed in the processing liquid LQ. As a result, it is possible to prevent the substrate W from shifting position when the substrate holder 120 immerses the substrate W in the processing liquid LQ during the period T2.

[0156] Furthermore, in this embodiment, the pump flow rate Pb during the pre-treatment period T2 is smaller than the pump flow rate Pa during the periods T1, T4, and T5 when the substrate W is not immersed in the treatment liquid LQ. In other words, the second control unit A2 controls the pump 142 so that the flow rate Pb of the treatment liquid LQ flowing through the circulation piping 141 during the pre-treatment period T2 is smaller than the flow rate Pa of the treatment liquid LQ flowing through the circulation piping 141 during the periods T1, T4, and T5 when the substrate W is not immersed in the treatment liquid LQ. In this case, the dissolved oxygen concentration can be further reduced during the period T2.

[0157] Furthermore, in this embodiment, the flow rate Gc of the second inert gas GA2 supplied to the outer bath 110 is constant from period T1 to period T5. That is, from period T1 to period T5, the third controller A3 sets the aperture of the valve 26 so that the flow rate Gc of the second inert gas GA2 is constant. As a result, dissolution of oxygen into the processing liquid LQ in the outer bath 110 can be stably suppressed from period T1 to period T5.

[0158] In this specification, the term "flow rate of the processing liquid LQ flowing through the circulation pipe 141" can also be read as "the flow rate of the processing liquid LQ delivered by the pump 142."

[0159] Next, a substrate processing method according to this embodiment will be described with reference to Fig. 1 and Fig. 13 to Fig. 15. The substrate processing method is performed by a substrate processing apparatus 100. Fig. 13 and Fig. 14 are flowcharts showing an example of the substrate processing method according to this embodiment. As shown in Fig. 13 and Fig. 14, the substrate processing method includes steps S1 to S14.

[0160] 1 and 13, first, in step S1, the control unit 221 of the substrate processing apparatus 100 controls the processing liquid supply unit 150 (FIG. 7) and the processing liquid introduction unit 125 so as to supply the processing liquid LQ to the empty processing tank 105. As a result, the supply of the processing liquid LQ to the empty processing tank 105 is started. Specifically, the control unit 221 controls the processing liquid supply unit 150 so as to supply the processing liquid LQ to the outer bath 110. Furthermore, the control unit 221 controls the processing liquid introduction unit 125 so as to introduce the processing liquid LQ from the outer bath 110 into the processing tank 105. In this case, the second control unit A2 of the control unit 221 sets the flow rate of the processing liquid LQ delivered by the pump 142 of the processing liquid introduction unit 125 to a flow rate Pa (liters / minute).

[0161] Next, in step S2, the control unit 221 determines whether or not a predetermined amount of the processing liquid LQ has been supplied.

[0162] If it is determined in step S2 that the predetermined amount of the processing liquid LQ has not been supplied (No), the supply of the processing liquid LQ continues until the predetermined amount of the processing liquid LQ has been supplied.

[0163] On the other hand, if it is determined in step S2 that a predetermined amount of processing liquid LQ has been supplied (Yes), the process proceeds to step S3.

[0164] Next, in step S3, the control unit 221 controls the processing liquid supply unit 150 to stop the supply of the processing liquid LQ. Meanwhile, the processing liquid introduction unit 125 continues to introduce the processing liquid LQ from the outer bath 110 to the processing tank 105. Therefore, the processing liquid LQ in the processing tank 105 circulates through the outer bath 110 and the circulation pipe 141. In this case, the flow rate of the processing liquid LQ by the pump 142 of the processing liquid introduction unit 125 is a flow rate Pa (liters / minute).

[0165] Next, steps S4 and S5 are executed in parallel. Note that step S5 may be executed after step S4, or step S5 may be executed before step S4.

[0166] In step S4, the first control unit A1 of the control unit 221 controls the gas flow rate adjuster 180 to supply the first inert gas GA1 to the first gas supply pipes 21. As a result, each first gas supply pipe 21 discharges the first inert gas GA1 from each first discharge hole H1, thereby supplying a large number of bubbles BB to the processing liquid LQ in the processing tank 105. In step S4, the gas flow rate adjuster 180 sets the flow rate of the first inert gas GA1 to a flow rate Ga (liters / minute). Step S4 corresponds to an example of a "first gas supply step of supplying the first inert gas GA1 to the processing liquid LQ stored in the processing tank 105" of the present invention.

[0167] Meanwhile, in step S5, the third control unit A3 of the control unit 221 controls the valve 26 (FIG. 5) to supply the second inert gas GA2 to the second gas supply pipe 25. As a result, the second gas supply pipe 25 discharges the second inert gas GA2 from each second discharge hole H2 into the outer tank 110. In step S5, the valve 26 sets the flow rate of the second inert gas GA2 to a flow rate Gc (liters / minute). Step S5 corresponds to an example of a "second gas supply step of supplying the second inert gas GA2 into the outer tank 110" of the present invention.

[0168] 14, in step S6, the control unit 221 determines whether or not a first time has elapsed since the supply of the treatment liquid LQ was stopped (step S3). The first time is determined experimentally and / or empirically based on the dissolved oxygen concentration of the treatment liquid LQ.

[0169] If it is determined in step S6 that the first time has not elapsed (No), the control waits until the first time has elapsed.

[0170] On the other hand, if it is determined in step S6 that the first time period has elapsed (Yes), the process proceeds to step S7.

[0171] Next, in step S7, the second control unit A2 controls the pump 142 so that the flow rate Pb of the treatment liquid LQ flowing through the circulation pipe 141 is smaller than the flow rate Pa (step S3). In other words, the second control unit A2 changes the flow rate of the treatment liquid LQ sent out by the pump 142 from the flow rate Pa (step S3) to a flow rate Pb that is smaller than the flow rate Pa.

[0172] Next, in step S8, the first control unit A1 controls the gas flow rate adjuster 180 so that the flow rate Gb of the first inert gas GA1 supplied to the first gas supply pipe 21 is smaller than the flow rate Ga (step S4). As a result, the amount of bubbles BB supplied to the processing liquid LQ decreases.

[0173] Next, in step S9, the control unit 221 controls the substrate holding unit 120 so as to immerse the substrate W in the processing liquid LQ. As a result, the substrate holding unit 120 immerses the substrate W in the processing liquid LQ.

[0174] Next, in step S10, the control unit 221 determines whether a second time has elapsed since the substrate W was immersed in the processing liquid LQ (step S9). The second time is determined experimentally and / or empirically based on the processing amount required for the substrate W.

[0175] If it is determined in step S10 that the second time has not elapsed (No), the control waits until the second time has elapsed.

[0176] On the other hand, if it is determined in step S10 that the second time has elapsed (Yes), the process proceeds to step S11.

[0177] Next, in step S11, the control unit 221 controls the substrate holding unit 120 so as to lift the substrate W out of the processing liquid LQ. As a result, the substrate holding unit 120 lifts the substrate W out of the processing liquid LQ.

[0178] Next, in step S12, the second control unit A2 controls the pump 142 so that the flow rate Pa of the treatment liquid LQ flowing through the circulation pipe 141 is greater than the flow rate Pb (step S7). In other words, the second control unit A2 sets the delivery flow rate of the treatment liquid LQ by the pump 142 from the flow rate Pb (step S7) to a flow rate Pa that is greater than the flow rate Pb.

[0179] Next, in step S13, the first control unit A1 controls the gas flow rate adjuster 180 so that the flow rate Ga of the first inert gas GA1 supplied to the first gas supply pipe 21 is greater than the flow rate Gb (step S8). As a result, the amount of bubbles BB supplied to the processing liquid LQ increases.

[0180] Next, in step S14, the control unit 221 determines whether or not the pre-processing timing has arrived.

[0181] If it is determined in step S14 that the pre-processing timing has not arrived (No), the control waits until the pre-processing timing arrives.

[0182] On the other hand, if it is determined in step S14 that the pre-processing timing has arrived (Yes), the process proceeds to step S7. Thereafter, steps S7 to S14 are repeated.

[0183] As described above with reference to FIGS. 13 and 14 , in the substrate processing method according to this embodiment, the first inert gas GA1 (gas bubbles BB) is supplied to the processing liquid LQ in the processing tank 105 (steps S4, S8, and S13), thereby replacing the oxygen dissolved in the processing liquid LQ with the first inert gas GA1. Therefore, the dissolved oxygen concentration of the processing liquid LQ in the processing tank 105 can be reduced. As a result, the amount of substrates W processed by the processing liquid LQ can be increased. In particular, since the second inert gas GA2 is supplied to the interior of the outer tank 110 (step S5), dissolution of oxygen in the processing liquid LQ in the outer tank 110 can be suppressed. Therefore, the processing liquid LQ with a low dissolved oxygen concentration is introduced from the outer tank 110 into the processing tank 105 by the processing liquid introduction part 125. As a result, it is possible to suppress "an increase in the dissolved oxygen concentration of the processing liquid LQ in the processing tank 105 due to the processing liquid LQ introduced from the outer tank 110." Therefore, the substrate W immersed in the processing liquid LQ can be processed more effectively by the processing liquid LQ. In this way, the effectiveness of the inert gas is increased, and the substrate W can be processed more effectively.

[0184] Next, a more preferred example of the substrate processing method according to this embodiment will be described with reference to Figures 1, 13, and 15. The first stage of the more preferred example of the substrate processing method includes steps S1 to S5 described with reference to Figure 13. Figure 15 is a flowchart showing the second stage of the more preferred example of the substrate processing method. As shown in Figure 15, the second stage of the substrate processing method includes steps S101 to S109.

[0185] In step S101, the control unit 221 determines whether or not a first time has elapsed since the supply of the treatment liquid LQ was stopped (step S3).

[0186] If it is determined in step S101 that the first time has not elapsed (No), the control waits until the first time has elapsed.

[0187] On the other hand, if it is determined in step S101 that the first time period has elapsed (Yes), the process proceeds to step S102.

[0188] Next, in step S102, the second control unit A2 stops the pump 142. Therefore, the circulation of the processing liquid LQ through the circulation pipe 141 is stopped. In other words, the flow rate of the processing liquid LQ in the circulation pipe 141 is zero. As a result, the introduction of the processing liquid LQ from the outer bath 110 into the processing bath 105 is stopped.

[0189] Next, steps S103 to S106 are executed. Steps S103 to S106 are similar to steps S8 to S11 in FIG.

[0190] Next, in step S107, the second control unit A2 drives the pump 142. Therefore, the circulation of the processing liquid LQ through the circulation pipe 141 begins. As a result, the introduction of the processing liquid LQ from the outer bath 110 into the processing bath 105 begins. In this case, the second control unit A2 sets the flow rate of the processing liquid LQ delivered by the pump 142 to the flow rate Pa (step S3 in FIG. 13).

[0191] Next, in step S108, the first control unit A1 controls the gas flow rate adjuster 180 so that the flow rate Ga of the first inert gas GA1 supplied to the first gas supply pipe 21 is greater than the flow rate Gb (step S103). As a result, the amount of bubbles BB supplied to the processing liquid LQ increases.

[0192] Next, in step S109, the control unit 221 determines whether or not the pre-processing timing has arrived.

[0193] If it is determined in step S109 that the pre-processing timing has not arrived (No), the control waits until the pre-processing timing arrives.

[0194] On the other hand, if it is determined in step S109 that the pre-processing timing has arrived (Yes), the process proceeds to step S102. Thereafter, steps S102 to S109 are repeated.

[0195] 15, according to a preferred example of the substrate processing method, the pump 142 is stopped while the substrate W is immersed in the processing liquid LQ (step S102). As a result, while the substrate W is being processed, the dissolved oxygen concentration of the processing liquid LQ in the processing tank 105 can be more effectively reduced.

[0196] (First Modification) A first modified example of this embodiment will be described with reference to Figures 16 and 17. The first modified example differs from the embodiment described above with reference to Figure 1 mainly in that the contact portion 52X of the first lid 111 is inclined. Below, the differences between the first modified example and the embodiment will be mainly described.

[0197] 16 is a schematic cross-sectional view showing a substrate processing apparatus 100A according to a first modified example, in which the substrate holding unit 120, the processing liquid introduction unit 125, the gas flow rate adjuster 180, and the control device 220 shown in FIG.

[0198] 16, the first lid 111 of the substrate processing apparatus 100A includes a contact portion 52X. When the first lid 111 is closed, the contact portion 52X is spaced apart from the substrates W in the vertical direction D. Furthermore, when the first lid 111 is closed, the contact portion 52X is in contact with the processing liquid LQ in the processing tank 105 from above the processing liquid LQ in the processing tank 105.

[0199] Specifically, the contact portion 52X includes a first inclined portion 55a and a second inclined portion 55b. More specifically, the first inclined portion 55a is the bottom of the first contact portion 52a. The second inclined portion 55b is the bottom of the second contact portion 52b.

[0200] When the first lid 111 covers the upper opening 106a of the processing tank 105 (when the first lid 111 is closed), the first inclined portion 55a slopes obliquely upward from a position PS facing the tops TP of the substrates W toward one of the side walls 105a of the pair of side walls 105a, 105b of the processing tank 105. That is, when the first lid 111 covers the upper opening 106a of the processing tank 105, the first inclined portion 55a slopes obliquely upward from the lowermost portion of the contact portion 52X toward one of the side walls 105a. Therefore, air bubbles BB that reach the liquid surface of the processing liquid LQ are collected by buoyancy along the first inclined portion 55a toward the side wall 105a. As a result, it is possible to prevent air bubbles BB that reach the liquid surface from accumulating near the position PS.

[0201] When the first lid 111 covers the upper opening 106a of the processing tank 105 (when the first lid 111 is closed), the second inclined portion 55b inclines obliquely upward from a position PS facing the tops TP of the substrates W toward the other side wall 105b of the pair of side walls 105a, 105b. In other words, when the first lid 111 covers the upper opening 106a of the processing tank 105, the second inclined portion 55b inclines obliquely upward from the lowermost portion of the contact portion 52X toward the other side wall 105a.

[0202] Therefore, the air bubbles BB that reach the liquid surface of the processing liquid LQ gather along the second inclined portion 55b toward the side wall 105b due to buoyancy. As a result, it is possible to prevent the air bubbles BB that reach the liquid surface from accumulating near the position PS.

[0203] 16, according to the first modified example, by providing the first inclined portion 55a and the second inclined portion 55b, it is possible to prevent the bubbles BB that have reached the liquid surface from accumulating near the position PS. As a result, it is possible to prevent the bubbles BB that have reached the liquid surface of the processing liquid LQ from contacting the top part TP of the substrate W. This makes it possible to prevent the processing near the top part TP of the substrate W from being hindered by the bubbles BB that have reached the liquid surface.

[0204] Furthermore, in the first modified example, the first contact portion 52a and the second contact portion 52b are immersed in the processing liquid LQ in the processing tank 105. This prevents the liquid surface of the processing liquid LQ from coming into contact with oxygen. As a result, it is possible to prevent oxygen from dissolving in the processing liquid LQ.

[0205] Next, the rotation mechanism of the first cover body 111 will be described with reference to Fig. 17. Fig. 17 is a schematic diagram showing the first cover body 111 in a closed state. As shown in Fig. 17, when the first hinged door section 50a and the second hinged door section 50b are closed, the first rotation shaft 61a and the second rotation shaft 61b are positioned below the area Za of the first hinged door section 50a and the area Zb of the second hinged door section 50b. As a result, interference between the first hinged door section 50a and the second hinged door section 50b is prevented, allowing the first hinged door section 50a and the second hinged door section 50b to be opened and closed smoothly.

[0206] The region Za is the lowermost portion of the first contact portion 52a at the center of the contact portion 52X in the second direction D20 when the first swing door portion 50a and the second swing door portion 50b are closed. That is, the region Za is the lowermost portion of the first inclined portion 55a. Furthermore, the region Zb is the lowermost portion of the second contact portion 52b at the center of the contact portion 52X in the second direction D20 when the first swing door portion 50a and the second swing door portion 50b are closed. That is, the region Zb is the lowermost portion of the second inclined portion 55b.

[0207] (Second Modification) A second modified example of this embodiment will be described with reference to Figures 18 and 19. The second modified example differs from the embodiment described above with reference to Figure 1 mainly in that the second gas supply unit 210 supplies the second inert gas GA2 upward. Below, the differences between the second modified example and the embodiment described above will be mainly described.

[0208] Fig. 18 is a schematic cross-sectional view showing a substrate processing apparatus 100B according to a second modified example. Fig. 19 is a schematic cross-sectional view showing an outer tank 110 and a second gas supply pipe 25. Fig. 19 shows a state in which the outer tank 110 and the second gas supply pipe 25 shown on the right side of Fig. 18 are cut along a plane parallel to the YZ plane of Fig. 18.

[0209] 18, in the substrate processing apparatus 100B, the second gas supply unit 210 is disposed inside the outer bath 110 and discharges the second inert gas GA2 upward from each second discharge hole H2. This effectively prevents oxygen from dissolving in the processing liquid LQ stored in the outer bath 110. This is because the second inert gas GA2 easily fills the outer bath 110. Preferably, the second gas supply unit 210 is disposed in the processing liquid LQ in the outer bath 110. In this case, the dissolved oxygen concentration in the processing liquid LQ can be effectively reduced. Note that "upward" refers to, for example, the upper side in the vertical direction D (vertically upward).

[0210] 19 , in the second gas supply pipe 25, the multiple second discharge holes H2 are arranged in a substantially straight line at intervals in the first direction D10. The second gas supply pipe 25 is arranged inside the outer tank 110, and the second inert gas GA2 is discharged upward from each of the second discharge holes H2. In this case, for example, the second discharge holes H2 face upward in the vertical direction D. That is, the second discharge holes H2 are arranged at an upper part of the second gas supply pipe 25. Preferably, the second gas supply pipe 25 is arranged in the processing liquid LQ in the outer tank 110. Specifically, the second gas supply pipe 25 is arranged in the processing liquid LQ in the outer tank 110 on the bottom side of the first storage section 117a of the outer tank 110, the bottom side of the second storage section 117b (FIG. 5), the bottom side of the fourth storage section 117d (FIG. 5), and the upper side of the third storage section 117c.

[0211] Next, the present invention will be described in detail based on examples, but the present invention is not limited to the following examples. [Example]

[0212] In Examples 1, 2, and 3 of the present invention, the substrate processing apparatus 100 shown in Fig. 1 was used. In order to simplify the experimental system, the second gas supply unit 210 was not used.

[0213] TMAH was used as the processing liquid LQ, and nitrogen was used as the first inert gas GA1.

[0214] Example 1 In Example 1 of the present invention, the time change in the dissolved oxygen concentration of the processing liquid LQ was measured for each pump flow rate (the flow rate of the processing liquid LQ delivered by the pump 142) without supplying the first inert gas GA1 (bubbles BB) to the processing liquid LQ. Specifically, the flow rate of the first inert gas GA1 was 0 liters / minute. In other words, bubbles BB of the first inert gas GA1 were not supplied to the processing liquid LQ. Example 1 aimed to measure the pump flow rate dependency of the dissolved oxygen concentration, and this was done to reduce the number of variables. In addition, the second inert gas GA2 was not used. Example 1 aimed to measure the pump flow rate dependency of the dissolved oxygen concentration, and this was done to simplify the experimental system.

[0215] FIG. 20 is a graph showing the change over time in the dissolved oxygen concentration of the treatment liquid LQ in Example 1 (without the first inert gas GA1). The horizontal axis represents time (minutes), and the vertical axis represents the dissolved oxygen concentration (ppm) of the treatment liquid LQ. In FIG. 20, plot Q1 represents the change over time in the dissolved oxygen concentration when the pump flow rate is 0 liters / minute. That is, plot Q1 represents the change over time in the dissolved oxygen concentration when the pump 142 is stopped. Plot Q2 represents the change over time in the dissolved oxygen concentration when the pump flow rate is 5 liters / minute. Plot Q3 represents the change over time in the dissolved oxygen concentration when the pump flow rate is 10 liters / minute.

[0216] 20, in all of the plots Q1 to Q3, the dissolved oxygen concentration increased over time as oxygen in the atmosphere dissolved in the treatment liquid LQ. Furthermore, as can be seen from the plots Q1 to Q3, the rate of increase in the dissolved oxygen concentration slowed as the pump flow rate decreased. This was presumably because the smaller the pump flow rate, the more difficult it was for oxygen in the atmosphere to dissolve in the treatment liquid LQ.

[0217] Example 2 In Example 2 of the present invention, the change over time in the dissolved oxygen concentration of the processing liquid LQ was measured while supplying the first inert gas GA1 (bubbles BB) to the processing liquid LQ for each pump flow rate (the flow rate of the processing liquid LQ delivered by the pump 142). Specifically, the flow rate of the first inert gas GA1 was 10 liters / minute. That is, in Example 2, the purpose was also to confirm the effect of reducing the dissolved oxygen concentration by the bubbles BB of the first inert gas GA1. Note that the flow rate of the first inert gas GA1 indicates the flow rate supplied to one first gas supply pipe 21. Furthermore, the second inert gas GA2 was not used. This is because Example 2 aimed to measure the dependency of the dissolved oxygen concentration on the pump flow rate, and the experimental system was simplified.

[0218] FIG. 21 is a graph showing the change over time in the dissolved oxygen concentration of the treatment liquid LQ in Example 2 (with the first inert gas GA1). The horizontal axis represents time (minutes), and the vertical axis represents the dissolved oxygen concentration (ppm) of the treatment liquid LQ. In FIG. 21, plot Q4 represents the change over time in the dissolved oxygen concentration when the pump flow rate is 0 liters / minute. That is, plot Q4 represents the change over time in the dissolved oxygen concentration when the pump 142 is stopped. Plot Q5 represents the change over time in the dissolved oxygen concentration when the pump flow rate is 5 liters / minute. Plot Q6 represents the change over time in the dissolved oxygen concentration when the pump flow rate is 10 liters / minute.

[0219] As shown in FIG. 21, in all of the plots Q4 to Q6, the dissolved oxygen concentration of the treatment liquid LQ decreased over time due to the bubbles BB of the first inert gas GA1. Furthermore, as can be seen from the plots Q4 to Q6, the rate at which the dissolved oxygen concentration decreased was faster as the pump flow rate decreased. This is presumably because the oxygen in the atmosphere becomes more difficult to dissolve in the treatment liquid LQ as the pump flow rate decreases. Furthermore, as can be seen from the plots Q4 to Q6, the dissolved oxygen concentration of the treatment liquid LQ converged to a substantially constant level over time. Furthermore, in a state in which the dissolved oxygen concentration had converged to a substantially constant level, the smaller the pump flow rate, the lower the dissolved oxygen concentration of the treatment liquid LQ.

[0220] Example 3 In Example 3 of the present invention, the change over time in the dissolved oxygen concentration of the treatment liquid LQ was measured for each flow rate of the first inert gas GA1. In order to simplify the experimental system, the second inert gas GA2 was not used. The pump flow rate (the flow rate of the treatment liquid LQ delivered by the pump 142) was 23 liters / minute.

[0221] FIG. 22 is a graph showing the change over time in the dissolved oxygen concentration of the processing liquid LQ for each flow rate of the first inert gas GA1 in Example 3. The horizontal axis represents time (minutes), and the vertical axis represents the dissolved oxygen concentration (ppm) of the processing liquid LQ. In FIG. 22, plot Q7 represents the change over time in the dissolved oxygen concentration when the flow rate of the first inert gas GA1 is 30 liters / minute. Plot Q8 represents the change over time in the dissolved oxygen concentration when the flow rate of the first inert gas GA1 is 20 liters / minute. Plot Q9 represents the change over time in the dissolved oxygen concentration when the flow rate of the first inert gas GA1 is 10 liters / minute. The flow rate of the first inert gas GA1 represents the flow rate supplied to one first gas supply pipe 21.

[0222] As shown in FIG. 22, in all of plots Q7 to Q9, the dissolved oxygen concentration of the treatment liquid LQ decreased over time due to the bubbles BB of the first inert gas GA1. Furthermore, as can be seen from plots Q7 to Q9, the rate at which the dissolved oxygen concentration decreased was faster as the flow rate of the first inert gas GA1 increased. This is presumably because the replacement of oxygen in the treatment liquid LQ with the first inert gas GA1 is promoted as the flow rate of the first inert gas GA1 increases. Furthermore, as can be seen from plots Q7 to Q9, the dissolved oxygen concentration of the treatment liquid LQ converged to a substantially constant level over time. Furthermore, in a state in which the dissolved oxygen concentration had converged to a substantially constant level, the dissolved oxygen concentration of the treatment liquid LQ decreased as the flow rate of the first inert gas GA1 increased.

[0223] The embodiments of the present invention have been described above with reference to the drawings. However, the present invention is not limited to the above embodiments and can be implemented in various forms without departing from the spirit of the present invention. Furthermore, the components disclosed in the above embodiments can be modified as appropriate. For example, some of the components shown in one embodiment may be added to the components of another embodiment, or some of the components shown in one embodiment may be deleted from the embodiment.

[0224] Furthermore, the drawings mainly show each component in a schematic manner to facilitate understanding of the invention, and the thickness, length, number, spacing, etc. of each component shown in the drawings may differ from the actual ones due to the convenience of creating the drawings. Furthermore, the configuration of each component shown in the above embodiment is merely an example and is not particularly limited, and it goes without saying that various modifications are possible within a range that does not substantially deviate from the effects of the present invention.

[0225] (1) In Fig. 1, a gas flow rate adjustment mechanism 182 is provided for each of the plurality of first gas supply pipes 21. However, one gas flow rate adjustment mechanism 182 may be provided in common to the plurality of first gas supply pipes 21.

[0226] (2) The number of first gas supply pipes 21 shown in Fig. 1 is not particularly limited and may be an even number or an odd number. Furthermore, the positions of the multiple first gas supply pipes 21 in the vertical direction D may or may not be aligned. Furthermore, the orientation of the first discharge holes H1 is not particularly limited and may be, for example, oriented diagonally upward, diagonally downward, horizontally, or vertically downward.

[0227] (3) The second gas supply unit 210 in Fig. 5 may be provided with a gas flow rate adjustment mechanism having a configuration similar to that of the gas flow rate adjustment mechanism 182 (Fig. 10) instead of the valve 26. In this case, the gas flow rate adjustment mechanism adjusts the flow rate of the second inert gas GA2 under the control of the third control unit A3.

[0228] (4) The orientation of the second discharge holes H2 in FIGS. 6 and 19 is not particularly limited, and may be oriented obliquely upward, obliquely downward, or horizontally, for example. [Industrial Applicability]

[0229] The present invention relates to a substrate processing apparatus and a substrate processing method, and has industrial applicability. [Explanation of symbols]

[0230] 52, 52X contact part 55a 1st slope part 55b 2nd slope part 100, 100A, 100B Substrate processing equipment 105 Treatment tank 105a, 105b side wall 110 Outer tank 111 First lid 112 Second lid 120 Board holding part 141 Circulation piping (piping) 142 Pump 180 Gas flow rate control unit 200 First gas supply unit 210 Second gas supply unit A1 First control section A2 2nd control section W substrate

Claims

1. a processing tank for storing a processing liquid in which the substrate is immersed; a first lid for covering an upper opening of the treatment tank; an outer tank disposed outside the treatment tank, into which the treatment liquid overflowing from the treatment tank flows; a processing liquid introduction section capable of introducing the processing liquid stored in the outer tank into the processing tank; a first gas supply unit that supplies a first inert gas to the processing liquid stored in the processing tank; a second gas supply unit that supplies a second inert gas into the outer tank; a gas flow rate adjusting unit that adjusts the flow rate of the first inert gas; a first control unit that controls the gas flow rate adjusting unit; Equipped with The first control unit controls the gas flow rate adjustment unit so that the flow rate of the first inert gas during a period when the substrate is not immersed in the processing liquid is greater than the flow rate of the first inert gas during a period when the substrate is immersed in the processing liquid.

2. 2 . The substrate processing apparatus according to claim 1 , wherein the first control unit controls the gas flow rate adjusting unit so that the flow rate of the first inert gas becomes a maximum flow rate during the period when the substrate is not immersed in the processing liquid.

3. A processing tank for storing a processing liquid in which a substrate is immersed; a first lid for covering an upper opening of the treatment tank; an outer tank disposed outside the treatment tank, into which the treatment liquid overflowing from the treatment tank flows; a processing liquid introduction section capable of introducing the processing liquid stored in the outer tank into the processing tank; a first gas supply unit that supplies a first inert gas to the processing liquid stored in the processing tank; a second gas supply unit that supplies a second inert gas into the outer tank; Equipped with The treatment liquid introduction part a pipe connecting the outer tank and the treatment tank and through which the treatment liquid flows; a pump that delivers the processing solution from the outer tank to the processing tank through the piping; Including, Further, a second control unit is provided to control the pump. The second control unit controls the pump so that the flow rate of the processing liquid flowing through the piping during a period when the substrate is immersed in the processing liquid is smaller than the flow rate of the processing liquid flowing through the piping during a period when the substrate is not immersed in the processing liquid.

4. The substrate processing apparatus according to claim 3 , wherein the second control unit stops the pump during the period in which the substrate is immersed in the processing liquid.

5. 5. The substrate processing apparatus according to claim 3, wherein the second control unit controls the pump so that a flow rate of the processing liquid flowing through the piping becomes a maximum flow rate during the period when the substrate is not immersed in the processing liquid.

6. A processing tank for storing a processing liquid in which a substrate is immersed; a first lid for covering an upper opening of the treatment tank; an outer tank disposed outside the treatment tank, into which the treatment liquid overflowing from the treatment tank flows; a processing liquid introduction section capable of introducing the processing liquid stored in the outer tank into the processing tank; a first gas supply unit that supplies a first inert gas to the processing liquid stored in the processing tank; a second gas supply unit that supplies a second inert gas into the outer tank; a second lid for covering an upper opening of the outer tank; Equipped with The first lid covers the upper opening of the processing tank and the second lid.

7. a substrate holder that holds the plurality of substrates in a predetermined direction and immerses the plurality of substrates in the processing liquid stored in the processing tank; the treatment tank includes a pair of side walls extending along the predetermined direction, the first lid includes a contact portion that comes into contact with the treatment liquid, the contact portions are spaced apart from the plurality of substrates, The contact portion is a first inclined portion inclined obliquely upward from a position facing tops of the plurality of substrates toward one of the pair of side walls when the first lid is covering the upper opening of the processing tank; a second inclined portion inclined obliquely upward from the position facing the tops of the plurality of substrates toward the other side wall of the pair of side walls when the first lid is covering the upper opening of the processing tank; The substrate processing apparatus according to any one of claims 1 to 6, comprising:

8. 8. The substrate processing apparatus according to claim 1, wherein the second gas supply unit is disposed inside the outer tank and discharges the second inert gas downward.

9. 8. The substrate processing apparatus according to claim 1, wherein the second gas supply unit is disposed inside the outer tank and discharges the second inert gas upward.

10. The substrate processing apparatus according to claim 1 , wherein the processing liquid is alkaline.

11. A substrate processing method performed by a substrate processing apparatus including: a processing tank that stores a processing liquid in which a substrate is immersed for processing; an outer tank into which the processing liquid that overflows from the processing tank flows; and a processing liquid introduction unit that can introduce the processing liquid stored in the outer tank into the processing tank, a first gas supplying step of supplying a first inert gas to the processing liquid stored in the processing tank; a second gas supplying step of supplying a second inert gas into the outer tank; controlling the flow rate of the first inert gas so that the flow rate of the first inert gas during a period when the substrate is not immersed in the processing liquid is greater than the flow rate of the first inert gas during a period when the substrate is immersed in the processing liquid; A substrate processing method comprising:

12. A substrate processing method performed by a substrate processing apparatus including: a processing tank that stores a processing liquid in which a substrate is immersed for processing; an outer tank into which the processing liquid that overflows from the processing tank flows; and a processing liquid introduction unit that can introduce the processing liquid stored in the outer tank into the processing tank, The treatment liquid introduction part a pipe connecting the outer tank and the treatment tank and through which the treatment liquid flows; a pump that delivers the processing solution from the outer tank to the processing tank through the piping; Including, The substrate processing method includes: a first gas supplying step of supplying a first inert gas to the processing liquid stored in the processing tank; a second gas supplying step of supplying a second inert gas into the outer tank; controlling the pump so that the flow rate of the processing liquid flowing through the piping while the substrate is immersed in the processing liquid is smaller than the flow rate of the processing liquid flowing through the piping while the substrate is not immersed in the processing liquid; A substrate processing method comprising:

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