Substrate processing apparatus and substrate processing method

Abstract

The invention provides a substrate processing apparatus and a substrate processing method, which can inhibit the change of the phosphoric acid concentration of a phosphoric acid aqueous solution. A substrate processing apparatus is provided with: a substrate processing unit that immerses a substrate in a phosphoric acid aqueous solution; and a control unit that controls the substrate processing unit. The substrate processing unit is provided with: a processing tank having an inner tank for storing the aqueous phosphoric acid solution and an outer tank for collecting the aqueous phosphoric acid solution overflowing from the inner tank; a circulation line for conveying the phosphoric acid aqueous solution taken out from the outer tank to the inner tank; the liquid level sensor is used for detecting the liquid level of the phosphoric acid aqueous solution in the outer tank; and a pure water supply unit that supplies pure water to the processing tank, in which the substrate processing unit is configured to immerse the substrate in the phosphoric acid aqueous solution inside the inner tank. The control unit controls the supply flow rate of the pure water on the basis of the detected value of the liquid level height.

Description

Technical Field

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

[0002] Patent Document 1 describes a method for managing the boiling state of an aqueous phosphoric acid solution. In this method, the boiling state of the aqueous phosphoric acid solution is quantitatively evaluated based on the back pressure when an inert gas is purged inside the aqueous phosphoric acid solution.

[0003] Patent Document 2 describes correcting the phosphoric acid concentration of an aqueous phosphoric acid solution according to the atmospheric pressure. The higher the atmospheric pressure, the lower the phosphoric acid concentration is set.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2004-153164

[0007] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2016-039352 Summary of the Invention

[0008] Problems to be Solved by the Invention

[0009] One aspect of the present disclosure provides a technique for suppressing fluctuations in the phosphoric acid concentration of an aqueous phosphoric acid solution.

[0010] Solutions to the Problems

[0011] A substrate processing apparatus according to one aspect of the present disclosure includes: a substrate processing unit that immerses a substrate in an aqueous phosphoric acid solution; and a control unit that controls the substrate processing unit. The substrate processing unit includes: a processing tank having an inner tank and an outer tank, the inner tank for storing the aqueous phosphoric acid solution, and the outer tank for recovering the aqueous phosphoric acid solution that overflows from the inner tank; a circulation line for supplying the aqueous phosphoric acid solution taken out from the outer tank to the inner tank; a liquid level sensor that detects the liquid level height of the aqueous phosphoric acid solution in the outer tank; and a pure water supply unit that supplies pure water to the processing tank, wherein the substrate processing unit immerses the substrate in the aqueous phosphoric acid solution inside the inner tank. The control unit controls the supply flow rate of the pure water based on the detected value of the liquid level height.

[0012] Effects of the Invention

[0013] According to one aspect of the present disclosure, fluctuations in the phosphoric acid concentration of an aqueous phosphoric acid solution can be suppressed. Brief Description of the Drawings

[0014] Figure 1This is a diagram showing a substrate processing apparatus according to an embodiment.

[0015] Figure 2 This is a diagram showing an example of concentration control and flow rate control.

[0016] Figure 3 This is a diagram showing an example of the relationship between H2 and V.

[0017] Figure 4 This is a diagram showing an example of the relationship between N and ΔH2 (ΔH2 = H2a - H2b).

[0018] Figure 5 This is a diagram showing an example of the relationship between N and A.

[0019] Figure 6 This is a diagram showing an example of the relationship between A and H2.

[0020] Figure 7 This shows an example of the change over time of C, Q, and H2 in flow rate control.

[0021] Figure 8 This is a diagram showing a substrate processing apparatus according to a modified example.

[0022] Figure 9 This is a diagram showing an example of the timing of concentration control in a plurality of substrate processing units. Detailed Embodiment

[0023] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In addition, the same or corresponding structures are denoted by the same reference numerals in the respective drawings, and the description may sometimes be omitted. In this specification, the X-axis direction, the Y-axis direction, and the Z-axis direction are mutually perpendicular directions. The X-axis direction and the Y-axis direction are horizontal directions, and the Z-axis direction is the vertical direction. The X-axis direction includes the positive X-axis direction and the direction opposite to the positive X-axis direction, i.e., the negative X-axis direction. The Y-axis direction includes the positive Y-axis direction and the direction opposite to the positive Y-axis direction, i.e., the negative Y-axis direction. The Z-axis direction includes the positive Z-axis direction and the direction opposite to the positive Z-axis direction, i.e., the negative Z-axis direction. In addition, in this specification, the supply flow rate refers to the supply amount per unit time.

[0024] As Figure 1 shown, the substrate processing apparatus 1 includes: a substrate processing unit 10 that immerses a substrate W in a phosphoric acid aqueous solution L; and a control unit 90 that controls the substrate processing unit 10. The substrate W includes a silicon oxide film and a silicon nitride film, and the phosphoric acid aqueous solution L selectively etches the silicon nitride film among the silicon oxide film and the silicon nitride film. The phosphoric acid aqueous solution L includes phosphoric acid and water.

[0025] The substrate processing unit 10 includes a processing tank 20. The processing tank 20 has: an inner tank 21 for storing the phosphoric acid aqueous solution L; and an outer tank 22 for recovering the phosphoric acid aqueous solution L that overflows from the inner tank 21. The substrate processing unit 10 is configured to immerse the substrate W in the phosphoric acid aqueous solution L inside the inner tank 21. The liquid level height of the phosphoric acid aqueous solution L in the inner tank 21 is the same as the height of the upper end of the inner tank 21.

[0026] The substrate processing unit 10 includes a circulation line 30. The circulation line 30 is used to supply the phosphoric acid aqueous solution L taken out from the outer tank 22 to the inner tank 21. The phosphoric acid aqueous solution L that overflows from the inner tank 21 is recovered into the outer tank 22. The liquid level height of the phosphoric acid aqueous solution L in the outer tank 22 is different when the substrate W is immersed in the phosphoric acid aqueous solution L and when the substrate W is not immersed in the phosphoric acid aqueous solution L.

[0027] The substrate processing unit 10 is provided with a pump 31, a thermostat 32, and a filter 33 in the middle of the circulation line 30. The pump 31 pressurizes and conveys the phosphoric acid aqueous solution L. The thermostat 32 adjusts the temperature of the phosphoric acid aqueous solution L. The thermostat 32 includes a heater. The temperature of the phosphoric acid aqueous solution L is set to, for example, the boiling point of the phosphoric acid aqueous solution L. The filter 33 collects the fine particles contained in the phosphoric acid aqueous solution L.

[0028] The substrate processing unit 10 is provided with a horizontal tube 34 at the front end of the circulation line 30. The horizontal tube 34 extends in the X-axis direction, and a plurality of horizontal tubes 34 are provided at intervals in the Y-axis direction. The plurality of horizontal tubes 34 have a plurality of ejection ports at intervals in their long side directions. The plurality of ejection ports respectively eject the phosphoric acid aqueous solution L upward to form a curtain-like upward flow inside the inner tank 21.

[0029] The substrate processing unit 10 includes a substrate holding unit 40 and a lifting unit 45. The substrate holding unit 40 holds the substrate W. For example, the substrate holding unit 40 holds a plurality of substrates W at intervals in the X-axis direction and holds each substrate W vertically upright. The lifting unit 45 raises and lowers the substrate holding unit 40 between an immersion position where the substrate W is immersed in the phosphoric acid aqueous solution L and a standby position where the substrate W is lifted from the phosphoric acid aqueous solution L.

[0030] The substrate processing unit 10 includes a pure water supply unit 50 and a phosphoric acid supply unit 55. The pure water supply unit 50 supplies pure water to the processing tank 20 (preferably to the outer tank 22). The phosphoric acid supply unit 55 supplies phosphoric acid to the processing tank 20 (preferably to the outer tank 22). The pure water supply unit 50 and the phosphoric acid supply unit 55 each have, for example, an on-off valve and a flow controller.

[0031] The substrate processing unit 10 includes a discharge unit 59. The discharge unit 59 discharges the phosphoric acid aqueous solution L to the outside of the substrate processing apparatus 1. In the present embodiment, the discharge unit 59 discharges the phosphoric acid aqueous solution L from the bottom of the inner tank 21, but the phosphoric acid aqueous solution L may also be discharged from the circulation line 30. The discharge unit 59 has, for example, an on-off valve and a flow controller.

[0032] The discharge unit 59 periodically discharges at least a part of the phosphoric acid aqueous solution L. Thereafter, the phosphoric acid supply unit 55 supplies phosphoric acid to the processing tank 20 and the pure water supply unit 50 supplies pure water to the processing tank 20, thereby preparing the phosphoric acid aqueous solution L. The supply amounts of phosphoric acid and pure water are preset.

[0033] The control unit 90 is, for example, a computer, and includes an arithmetic unit 91 such as a CPU (Central Processing Unit) and a storage unit 92 such as a memory. Programs for controlling various processes executed in the substrate processing apparatus 1 are stored in the storage unit 92. The control unit 90 controls the operation of the substrate processing apparatus 1 by causing the arithmetic unit 91 to execute the programs stored in the storage unit 92.

[0034] The phosphoric acid aqueous solution L contains phosphoric acid and water. Water has a boiling point lower than that of phosphoric acid. During the boiling of the phosphoric acid aqueous solution L, water selectively evaporates. Therefore, the substrate processing apparatus 1 may also include an inspection line 60 and a concentration sensor 65. The inspection line 60 branches from the circulation line 30 downstream of the thermostat 32 and conveys the phosphoric acid aqueous solution L flowing in the circulation line 30 to the outer tank 22. By the inspection line 60, the retention of the phosphoric acid aqueous solution L can be suppressed, and thus the temperature drop of the phosphoric acid aqueous solution L can be suppressed. The concentration sensor 65 detects the phosphoric acid concentration C of the phosphoric acid aqueous solution L flowing in the inspection line 60. The concentration sensor 65 detects the phosphoric acid concentration C of the phosphoric acid aqueous solution L by detecting, for example, the refractive index of the phosphoric acid aqueous solution L.

[0035] After preparing the phosphoric acid aqueous solution L, the control unit 90 performs the following concentration control (see Figure 2 ). The concentration control is a feedback control in which the supply flow rate Q of pure water is controlled so that the detected value C_det of the phosphoric acid concentration C becomes the set value C_ref. Q is the supply flow rate of water supplied by the pure water supply unit 50 to the processing tank 20. The concentration control is performed in a state where the substrate W is not immersed in the phosphoric acid aqueous solution L in the inner tank 21 and the phosphoric acid supply unit 55 has stopped supplying phosphoric acid. In addition, the concentration control is performed in a state where the temperature of the phosphoric acid aqueous solution L is stable.

[0036] In addition, the control unit 90 can correct the set value C_ref of the phosphoric acid concentration C according to the atmospheric pressure. When the phosphoric acid concentration C is the same, the higher the atmospheric pressure, the higher the boiling point of the phosphoric acid aqueous solution L. On the other hand, when the atmospheric pressure is the same, the lower the phosphoric acid concentration C, the lower the boiling point of the phosphoric acid aqueous solution L. The higher the atmospheric pressure, the lower the control unit 90 controls the phosphoric acid concentration C, whereby the temperature of the phosphoric acid aqueous solution L can be maintained constant, and the boiling state (e.g., the size and number of bubbles) of the phosphoric acid aqueous solution L can be maintained constant. In addition, the temperature of the phosphoric acid aqueous solution L is maintained constant because the phosphoric acid aqueous solution L has a large volume and a large heat capacity, and it takes time to change the temperature.

[0037] The control unit 90 calculates the average value Qave of the supply flow rate Q of pure water in at least a part of the period P1 within the period P during which the concentration control is performed. The average value Qave corresponds to the evaporation rate V of water per unit time in the phosphoric acid aqueous solution L. Preferably, the control unit 90 calculates the average value Qave in a part of the period P1 of the period P during which the concentration control is performed. A part of the period P1 is preferably the period immediately before the end of the period P during which the concentration control is performed (e.g., 5 minutes). In addition, the time is not limited to 5 minutes.

[0038] After performing the concentration control, the control unit 90 performs the following flow rate control (refer to Figure 2 ). In the flow rate control, the supply flow rate Q of pure water is controlled based on the average value Qave of the supply flow rate Q of pure water calculated in advance. For example, the control unit 90 fixes the supply flow rate Q of pure water to the average value Qave. Thereby, the variation of the phosphoric acid concentration C can be suppressed without referring to the detected value C_det of the phosphoric acid concentration C. Therefore, it is possible to suppress the variation of the phosphoric acid concentration C in the plurality of substrate processing units 10 using one concentration sensor 65, and the details will be described later.

[0039] In the flow rate control, the control unit 90 can not only fix the supply flow rate Q of pure water to the average value Qave, but also correct the supply flow rate Q of pure water based on the average value Qave. For example, the control unit 90 can correct the supply flow rate Q of pure water according to the change amount ΔH2 of the liquid level height H2 of the phosphoric acid aqueous solution L in the outer tank 22 during the flow rate control. This is because the evaporation rate V of water per unit time in the phosphoric acid aqueous solution L depends on the liquid level height H2, and the details will be described later.

[0040] The evaporation rate V of water per unit time in the phosphoric acid aqueous solution L depends on the area of the interface between the phosphoric acid aqueous solution L and the atmosphere. The larger the area of the interface between the phosphoric acid aqueous solution L and the atmosphere, the larger the evaporation rate V. The interface between the phosphoric acid aqueous solution L and the atmosphere includes the liquid level of the phosphoric acid aqueous solution L in the inner tank 21 and the liquid level of the phosphoric acid aqueous solution L in the outer tank 22. The areas of these liquid levels are fixed.

[0041] The interface between the phosphoric acid aqueous solution L and the atmosphere also includes the side surface of the phosphoric acid aqueous solution L flowing down along the side surface of the inner tank 21 from the upper end of the inner tank 21. The area of this side surface is proportional to the drop of the flowing phosphoric acid aqueous solution L. This drop is equal to the height difference ΔH (ΔH = H1 - H2) between the liquid level height H1 of the phosphoric acid aqueous solution L in the inner tank 21 and the liquid level height H2 of the phosphoric acid aqueous solution L in the outer tank 22. Since H1 is fixed, ΔH depends on H2. In addition, the reference points of H1 and H2 may be points at the same height, and there is no particular limitation.

[0042] The larger the liquid level height H2 of the phosphoric acid aqueous solution L in the outer tank 22, the smaller the height difference ΔH, and the smaller the area of the interface between the phosphoric acid aqueous solution L and the atmosphere. Therefore, the larger the liquid level height H2, the smaller the evaporation amount V. The inventor of the present application noticed the situation that the evaporation amount V becomes smaller as the liquid level height H2 becomes larger. In addition, the liquid level height H2 may change due to the immersion or lifting of the substrate W, or the carry-out of the phosphoric acid aqueous solution L attached to the substrate W.

[0043] The substrate processing unit 10 is provided with a liquid level sensor 25. The liquid level sensor 25 detects the liquid level height H2 of the phosphoric acid aqueous solution L in the outer tank 22. The control unit 90 controls the supply flow rate Q of pure water based on the detected value H2_det of the liquid level height H2. Thus, even if the liquid level height H2 changes and the evaporation amount V changes, pure water can be replenished at a flow rate equivalent to the evaporation amount V. Therefore, the change in the phosphoric acid concentration C can be suppressed without using the concentration sensor 65.

[0044] The control unit 90 stores in advance the relationship between the liquid level height H2 and the evaporation amount V (for example Figure 3 the relationship shown). V is represented by a linear equation of H2. This is because V is proportional to the area of the interface between the phosphoric acid aqueous solution L and the atmosphere, and this area is represented by a linear equation of H2. The control unit 90 controls Q based on H2_det and the pre-stored relationship between H2 and V. For example, the control unit 90 calculates V by substituting H2_det as the value of H2 into the pre-stored relationship formula between H2 and V, and controls Q to make Q equal to the calculated V.

[0045] In addition, the control unit 90 can perform the following liquid level height control to obtain the relationship between H2 and V. The liquid level height control is a feedback control, in which the supply flow rate Q of pure water is controlled so that the detected value H2_det of the liquid level height H2 becomes the set value H2_ref. The Q that makes H2 fixed is V. The liquid level height control is performed in a state where the substrate W is not immersed in the phosphoric acid aqueous solution L in the inner tank 21 and the phosphoric acid supply unit 55 has stopped supplying phosphoric acid. In addition, the liquid level height control is performed in a state where the temperature of the phosphoric acid aqueous solution L is stable.

[0046] The control unit 90 changes the set value H2_ref of the liquid level height H2 to repeatedly perform the above-described liquid level height control to obtain the relationship between H2 and V. At this time, it is preferable to change the set value H2_ref in such a way that the set value H2_ref of the liquid level height H2 gradually decreases. Before and after the control unit 90 changes the set value H2_ref of the liquid level height H2, by discharging only a part of the phosphoric acid aqueous solution L to the outside of the substrate processing apparatus 1 through the discharging unit 59, the phosphoric acid concentration C can be maintained constant and the liquid level height H2 can be decreased.

[0047] In addition, as described above, the evaporation amount V is represented by a linear equation of the liquid level height H2. Therefore, the ratio R ΔV / ΔH2 (R ΔV / ΔH2 = ΔV / ΔH2) is constant (negative).

[0048] The control unit 90 can previously store the ratio R ΔV / ΔH2 , and correct the supply flow rate Q of pure water based on the change amount ΔH2_det of H2_det and the ratio R ΔV / ΔH2 . The correction amount can be the product of the ratio R ΔV / ΔH2 and the change amount ΔH2_det (R ΔV / ΔH2 ×ΔH2_det). Even if the liquid level height H2 changes and thus the evaporation amount V changes, pure water can be supplemented at a flow rate equivalent to the evaporation amount V.

[0049] The control unit 90 can correct the supply flow rate Q of pure water only when ΔH2_det is lower than the lower limit value or higher than the upper limit value. The lower limit value and the upper limit value are determined considering the detection error of H2. The correction of Q can also be performed multiple times until H2 becomes stable. In addition, when H2 is not stable even after the correction of Q is performed the set number of times, the control unit 90 can stop the correction of Q and output an alarm.

[0050] The control unit 90 can perform correction to reduce the supply flow rate Q of pure water when the substrate W is immersed in the phosphoric acid aqueous solution L in the inner tank 21. When the substrate W is immersed in the phosphoric acid aqueous solution L, an amount of the phosphoric acid aqueous solution L equivalent to the volume of the substrate W overflows from the inner tank 21 to the outer tank 22. As a result, the liquid level height H2 of the phosphoric acid aqueous solution L in the outer tank 22 becomes higher, and the evaporation amount V of water per unit time in the phosphoric acid aqueous solution L decreases. By reducing the supply flow rate Q of pure water, pure water can be supplemented at a flow rate equivalent to the evaporation amount V, thereby suppressing the change in the phosphoric acid concentration C.

[0051] The control unit 90 can calculate the correction amount (decrease amount) of Q during immersion based on the number N of substrates W immersed in the phosphoric acid aqueous solution L. As Figure 4As shown in FIG. 1 , ΔH2 (ΔH2=H2a-H2b) is proportional to the number N of substrates W. Here, H2a is H2 immediately after immersion, and H2b is H2 immediately before immersion. The ratio R of ΔH2 to N is ΔH2 / N (R ΔH2 / N =ΔH2 / N) is fixed.

[0052] For example, the control unit 90 stores R ΔH2 / N , based on R ΔH2 / N , R ΔV / ΔH2 and N to calculate the reduction in Q during immersion. The magnitude of this reduction is, for example, R ΔH2 / N , R ΔV / ΔH2 and the product of N (R ΔH2 / N ×R ΔV / ΔH2 During the immersion of the substrate W, pure water can be replenished at a flow rate corresponding to the evaporation amount V, so that the variation of the phosphoric acid concentration C can be suppressed.

[0053] In addition, the control unit 90 can perform correction to increase the supply flow rate Q of pure water when the substrate W is lifted from the phosphoric acid aqueous solution L. When the substrate W is lifted from the phosphoric acid aqueous solution L, the phosphoric acid aqueous solution L in an amount corresponding to the volume of the substrate W is sent from the outer tank 22 to the inner tank 21. As a result, the liquid level H2 of the phosphoric acid aqueous solution L in the outer tank 22 becomes lower, and the evaporation amount V of water in the phosphoric acid aqueous solution L per unit time increases. By increasing the supply flow rate Q of pure water, pure water can be replenished at a flow rate corresponding to the evaporation amount V, so that the change in the phosphoric acid concentration C can be suppressed.

[0054] For example, the control unit 90 may calculate the correction amount (increase amount) of Q when lifting based on the number N of substrates W immersed in the phosphoric acid aqueous solution L. For example, the control unit 90 stores R ΔH2 / N , based on R ΔH2 / N , R ΔV / ΔH2 The increase in Q when lifted is calculated by using N. The increase in Q when lifted can be the same as the decrease in Q when immersed, but it is preferred that the increase in Q when lifted is greater than the decrease in Q when immersed as described below.

[0055] When the substrate W is lifted from the phosphoric acid aqueous solution L, the phosphoric acid aqueous solution L attached to the substrate W is carried out to the outside of the processing tank 20. The amount A carried out is proportional to the number N of substrates W (see Figure 5 ). This is because the amount of phosphoric acid aqueous solution L attached to the substrate W is proportional to the number N of substrates W. Figure 5 As shown, the ratio of A to N is R A / N (R A / N =A / N) is fixed. In addition, Figure 6As shown, the greater the carry-out amount A of the phosphoric acid aqueous solution L, the lower the liquid level height H2 of the phosphoric acid aqueous solution L in the outer tank 22 becomes. The ratio R of ΔH2 to ΔA ΔH2 / ΔA (R ΔH2 / ΔA = ΔH2 / ΔA) is fixed.

[0056] Therefore, the control unit 90 can also calculate the correction amount (increase amount) of Q at the time of lifting based on the carry-out amount A. The magnitude of this increase amount is, for example, the product of R ΔH2 / N 、R ΔV / ΔH2 and N (R ΔH2 / N ×R ΔV / ΔH2 ×N) and the absolute value of the product of R ΔH2 / ΔA 、R A / N 、N and R ΔV / ΔH2 (R ΔH2 / ΔA ×R A / N ×N×R ΔV / ΔH2 ). The magnitude of the increase amount of Q at the time of lifting is larger than the magnitude of the decrease amount of Q at the time of dipping by an amount corresponding to the product (R ΔH2 / ΔA ×R A / N ×N×R ΔV / ΔH2 ).

[0057] Next, an example of the change over time of the phosphoric acid concentration C, the pure water supply flow rate Q, and the liquid level height H2 in the flow rate control will be described with reference to Figure 7 . In the flow rate control, the control unit 90 monitors the liquid level height H2 through the liquid level sensor 25 and controls the pure water supply flow rate Q based on the liquid level height H2. At the time of dipping, the liquid level height H2 becomes high, so the control unit 90 reduces the pure water supply flow rate Q. In addition, at the time of lifting, the liquid level height H2 becomes low, so the control unit 90 increases the pure water supply flow rate Q. And at the time of lifting, the substrate W carries out the phosphoric acid aqueous solution L attached to the substrate W to the outside of the processing tank 20, so the liquid level height H2 decreases compared to before dipping. Therefore, it is preferable that the magnitude of the increase amount of Q at the time of lifting is larger than the magnitude of the decrease amount of Q at the time of dipping. By controlling the pure water supply flow rate Q based on the liquid level height H2 in this way, the variation of the phosphoric acid concentration C can be suppressed without referring to the detected value C_det of the phosphoric acid concentration C.

[0058] Next, a modified example of the substrate processing apparatus 1 will be described with reference to Figure 8 and Figure 9 . Hereinafter, the differences from the above-described embodiment will be mainly described. The substrate processing apparatus 1 includes a plurality of substrate processing units 10, and an inspection line 60 is provided for each substrate processing unit 10. In addition, the substrate processing apparatus 1 includes a concentration sensor 65 and a switching valve 69 for switching the inspection line 60 connected to the concentration sensor 65. Thereby, the variation of the phosphoric acid concentration C in the plurality of substrate processing units 10 can be suppressed by using one concentration sensor 65.

[0059] As Figure 9 shown, the control unit 90 creates plans for the preparation, concentration control, and flow rate control of the phosphoric acid aqueous solution L for each of the substrate processing units 10A, 10B, and 10C such that the periods during which concentration control is performed in the multiple substrate processing units 10A, 10B, and 10C do not overlap. The plan for the flow rate control includes a plan for the immersion of the substrate W. The control unit 90 performs the preparation, concentration control, and flow rate control of the phosphoric acid aqueous solution L according to the created plans. Thereby, the processing efficiency of the substrate W can be improved.

[0060] When an abnormality in the phosphoric acid concentration C occurs, the transfer of the unprocessed substrate W into the substrate processing unit 10 in which the abnormality has occurred is aborted, and the phosphoric acid aqueous solution L is discharged and prepared. Thereafter, in the substrate processing unit 10 in which the abnormality has occurred, these controls are performed in the order of concentration control and flow rate control. Then, the substrate W is immersed during the flow rate control.

[0061] The embodiments of the substrate processing apparatus and the substrate processing method according to the present disclosure have been described above, but the present disclosure is not limited to the above embodiments. Various changes, corrections, substitutions, additions, deletions, and combinations can be made within the scope described in the claims. These also naturally belong to the technical scope of the present disclosure.

[0062] Description of Reference Numerals

[0063] 1: Substrate processing apparatus; 10: Substrate processing unit; 20: Processing tank; 21: Inner tank; 22: Outer tank; 25: Liquid level sensor; 30: Circulation line; 50: Pure water supply unit; 90: Control unit.

Claims

1. A substrate processing device comprising: a substrate processing unit that immerses a substrate in a phosphoric acid aqueous solution; and a control unit that controls the substrate processing unit. The substrate processing unit comprises: a processing tank having an inner tank and an outer tank, wherein the inner tank is used to store the phosphoric acid aqueous solution, and the outer tank is used to recover the phosphoric acid aqueous solution overflowing from the inner tank; a circulation line, which is used to transport the phosphoric acid aqueous solution taken out from the outer tank to the inner tank; a liquid level sensor, which detects the liquid level height H2 of the phosphoric acid aqueous solution in the outer tank; and a pure water supply unit, which supplies pure water to the processing tank, wherein: The substrate processing unit is used to immerse the substrate in the phosphoric acid aqueous solution inside the inner tank. The control unit controls the supply flow rate Q of the pure water based on the detection value H2_det of the liquid level H2.

2. The substrate processing apparatus according to claim 1, wherein: The control unit stores in advance the relationship between the liquid level height H2 and the evaporation amount V of water per unit time in the phosphoric acid aqueous solution, and controls the supply flow rate Q of the pure water based on the relationship and the detection value H2_det.

3. The substrate processing apparatus according to claim 2, wherein: The control unit stores in advance a ratio R of the change amount ΔV of the evaporation amount V to the change amount ΔH2 of the liquid level height H2. ΔV / ΔH2 , based on the change in the detection value H2_det and the ratio R ΔV / ΔH2 To correct the pure water supply flow rate Q, where R ΔV / ΔH2 =ΔV / ΔH2.

4. The substrate processing apparatus according to claim 1, wherein: The control unit performs correction to reduce the supply flow rate Q of the pure water when the substrate is immersed in the phosphoric acid aqueous solution, and performs correction to increase the supply flow rate Q of the pure water when the substrate is lifted out of the phosphoric acid aqueous solution.

5. The substrate processing apparatus according to claim 4, wherein: The control unit calculates a correction amount of the supply flow rate Q of the pure water based on the number N of the substrates.

6. The substrate processing apparatus according to claim 4, wherein: The control unit calculates a correction amount of the supply flow rate Q of the pure water based on an amount A of the phosphoric acid aqueous solution that is carried out of the processing tank by the substrate when the substrate is lifted out of the phosphoric acid aqueous solution.

7. The substrate processing apparatus according to claim 1, wherein: A plurality of substrate processing units are provided, and each substrate processing unit is provided with an inspection line, wherein the inspection line is an inspection line branched from the circulation line and is used to transport the phosphoric acid aqueous solution flowing in the circulation line to the outer tank, The substrate processing apparatus includes: a concentration sensor for detecting a phosphoric acid concentration of the phosphoric acid aqueous solution flowing in the inspection line; and a switching valve for switching the inspection line connected to the concentration sensor.

8. The substrate processing apparatus according to claim 7, wherein: The substrate processing unit includes a phosphoric acid supply unit, and the phosphoric acid supply unit supplies phosphoric acid to the processing tank. In a state where the substrate is not immersed in the phosphoric acid aqueous solution in the inner tank and the phosphoric acid supply unit stops supplying the phosphoric acid, the control unit performs concentration control to control the supply flow rate Q of the pure water so that the detection value C_det of the phosphoric acid concentration C becomes a set value C_ref.

9. The substrate processing apparatus according to claim 8, wherein: The control unit performs the following control: calculating an average value of the supply flow rate of the pure water during at least a part of a period during which the concentration control is performed; and performing flow rate control to control the supply flow rate of the pure water based on the calculated average value after the concentration control.

10. The substrate processing apparatus according to claim 9, wherein: The control unit performs control such that an average value of the supply flow rate of the pure water in a part of a period during which the concentration control is performed is calculated. The part of the period is a period immediately before the end of the period during which the concentration control is performed.

11. The substrate processing apparatus according to claim 8, wherein: In the plurality of substrate processing units, periods for performing the concentration control do not overlap.

12. A substrate processing method, comprising: Using the substrate processing apparatus according to any one of claims 1 to 11, the substrate is immersed in the phosphoric acid aqueous solution in the inner tank.

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