Storage device and storage method

Abstract

The present application provides a storage device and a storage method. A storage device of one embodiment of the present application includes a storage tank, a heating mechanism, and a control portion. The storage tank is used to store a treatment liquid containing a phosphoric acid aqueous solution and an additive. The heating mechanism is capable of heating the treatment liquid stored in the storage tank. The control portion performs a concentration maintenance process in which the heating mechanism is controlled to adjust the temperature of the treatment liquid so that the amount of evaporation of moisture in the treatment liquid in the storage tank approaches the amount of moisture absorption of the treatment liquid in the storage tank. According to the present application, a substrate treatment using a treatment liquid containing a phosphoric acid aqueous solution and a silicon solution can be appropriately performed.

Description

Technical Field

[0001] Embodiments of the present invention relate to a storage device and a storage method. Background Technology

[0002] In the prior art, it is known that in a substrate processing system, the substrate is immersed in an etching solution containing an aqueous phosphoric acid solution and a silicon solution to process the substrate (see Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-118092 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] The present invention provides a technique for substrate processing that can be appropriately implemented using a processing solution containing an aqueous solution of phosphoric acid and a silicon solution.

[0008] Technical means for solving problems

[0009] One embodiment of the storage device of the present invention includes a storage tank, a heating mechanism, and a control unit. The storage tank is used to store a treatment solution containing an aqueous phosphoric acid solution and additives. The heating mechanism is capable of heating the treatment solution stored in the storage tank. The control unit performs a concentration maintenance process, in which the heating mechanism is controlled to adjust the temperature of the treatment solution so that the amount of water evaporation from the treatment solution in the storage tank is close to the amount of moisture absorbed by the treatment solution in the storage tank.

[0010] Invention Effects

[0011] According to the present invention, substrate processing using a processing solution containing an aqueous phosphoric acid solution and a silicon solution can be appropriately carried out. Attached Figure Description

[0012] Figure 1 This is a schematic block diagram illustrating the configuration of the substrate processing system in the implementation method.

[0013] Figure 2 This is a flowchart illustrating the steps of the concentration adjustment process in the implementation method.

[0014] Figure 3 This is a diagram showing the configuration of the mixing device according to the implementation method.

[0015] Figure 4 This is a flowchart illustrating the steps of the gas supply and exhaust volume adjustment process in the mixing device of the embodiment.

[0016] Explanation of reference numerals in the attached figures

[0017] 1. Substrate Processing System

[0018] 10. Mixing device

[0019] 11. Phosphoric acid aqueous solution supply department

[0020] 12. Precipitation Inhibitor Supply Department

[0021] 14 cans

[0022] 15. Loop circuit

[0023] 15c Branch

[0024] 16 pumps

[0025] 17 Heaters

[0026] 22 Liquid delivery line

[0027] 24 Return Route

[0028] 30 Substrate Processing Unit

[0029] 31 Processing tank

[0030] 51 Back pressure valve

[0031] 52 Thermometer

[0032] 55 Flow Meter

[0033] W chip

[0034] M mixture

[0035] E etching solution Detailed Implementation

[0036] Hereinafter, the storage apparatus and storage method for implementing the present invention will be described in detail with reference to the accompanying drawings (hereinafter referred to as "Embodiments"). However, the present invention is not limited to these embodiments. Furthermore, the various embodiments can be appropriately combined without contradicting the processing content. In the following embodiments, the same reference numerals are used to mark the same parts, and repeated descriptions are omitted.

[0037] Furthermore, in the embodiments shown below, expressions such as "fixed," "orthogonal," "perpendicular," or "parallel" are sometimes used. However, the expressions described above do not need to be strictly "fixed," "orthogonal," "perpendicular," or "parallel." That is, each of the above expressions allows for deviations in manufacturing precision, setting precision, etc.

[0038] Furthermore, in the accompanying figures below, to facilitate understanding, the X-axis, Y-axis, and Z-axis directions are defined as mutually orthogonal, forming an orthogonal coordinate system with the positive Z-axis as the vertically upward direction. Additionally, the direction of rotation about the vertical axis is sometimes referred to as the θ direction.

[0039] In the prior art, it is known that in a substrate processing system, the substrate is processed by immersing it in an etching solution containing an aqueous solution of phosphoric acid and a silicon solution.

[0040] For example, by immersing the substrate in an aqueous solution of phosphoric acid (H3PO4), the silicon nitride film stacked between the silicon nitride film (SiN) and the silicon oxide film (SiO2) on the substrate can be selectively etched.

[0041] Furthermore, by adding silicon solution (aqueous solution containing silicon compounds) to the phosphoric acid aqueous solution, the selectivity of the silicon nitride film for etching the silicon oxide film can be improved.

[0042] On the other hand, when the silicon nitride film is etched, the silicon contained in the silicon nitride film dissolves into the etching solution, so sometimes the silicon concentration in the phosphoric acid aqueous solution becomes excessive. When the silicon concentration in the phosphoric acid aqueous solution becomes excessive, silicon oxide (SiO2) will precipitate on the silicon oxide film, and sometimes the precipitated silicon oxide will hinder the etching process of the substrate.

[0043] Therefore, it is desirable to be able to properly implement etching processes using an etchant containing an aqueous solution of phosphoric acid and a silicon solution.

[0044] For example, in the processing tank where the above-mentioned etching process is performed, a storage device is connected for storing a processing solution containing an aqueous phosphoric acid solution and an additive to inhibit the precipitation of silicon oxide. The storage device stores the processing solution and, at a predetermined time, such as when the silicon concentration of the etching solution becomes excessive, supplies the silicon-free processing solution into the processing tank to reduce the silicon concentration.

[0045] Here, the aforementioned processing solution is prone to concentration fluctuations due to moisture absorption. Specifically, the processing solution easily reduces the phosphoric acid concentration by absorbing moisture from the atmosphere (hygroscopic absorption). In the storage device, when the phosphoric acid concentration decreases, the phosphoric acid concentration in the processing tank supplied with the processing solution from the storage device also decreases, which may result in the etching process not being able to be performed properly.

[0046] Therefore, a technology is needed to properly manage the concentration of the treatment solution in storage devices.

[0047] <Composition of Substrate Processing System>

[0048] First, refer to Figure 1 The configuration of the substrate processing system 1 in the embodiment is explained. Figure 1This is a schematic block diagram illustrating the configuration of the substrate processing system 1 according to the embodiment. The substrate processing system 1 is an example of a substrate processing apparatus.

[0049] The substrate processing system 1 includes a mixing device 10 (an example of a storage device), a silicon solution supply unit 25, and a substrate processing unit 30.

[0050] The mixing device 10 mixes an aqueous phosphoric acid solution with a precipitation inhibitor (an example of an additive) to suppress the precipitation of silicon oxide, thereby generating a mixture M (an example of a processing solution). Furthermore, the mixing device 10 supplies the generated mixture M to the processing tank 31 of the substrate processing section 30.

[0051] The silicon solution supply unit 25 supplies a silicon-containing aqueous solution (hereinafter referred to as "silicon solution") to the processing tank 31 of the substrate processing unit 30.

[0052] The substrate processing unit 30 stores an etching solution E containing a mixture M and a silicon solution in a processing tank 31. Furthermore, the substrate processing unit 30 etches a wafer W (an example of a substrate) by immersing it in the etching solution E stored in the processing tank 31. In this embodiment, for example, the silicon nitride film formed between a silicon nitride film (SiN) and a silicon oxide film (SiO2) on the wafer W can be selectively etched.

[0053] (Mixing device)

[0054] The mixing device 10 includes a phosphoric acid aqueous solution supply unit 11, a precipitation inhibitor supply unit 12 (an example of an additive supply unit), a tank 14 (an example of a storage tank), and a circulation line 15.

[0055] The phosphoric acid aqueous solution supply unit 11 supplies phosphoric acid aqueous solution to tank 14. The phosphoric acid aqueous solution supply unit 11 has a phosphoric acid aqueous solution supply source 11a, a phosphoric acid aqueous solution supply line 11b, and a flow regulator 11c.

[0056] The phosphoric acid solution supply source 11a is, for example, a tank for storing phosphoric acid solution. The phosphoric acid solution supply line 11b connects the phosphoric acid solution supply source 11a to the tank 14, supplying phosphoric acid solution from the source 11a to the tank 14. A flow regulator 11c is installed on the phosphoric acid solution supply line 11b to regulate the flow rate of the phosphoric acid solution supplied to the tank 14. The flow regulator 11c consists of an on / off valve, a flow control valve, a flow meter, etc.

[0057] The precipitation inhibitor supply unit 12 supplies precipitation inhibitor to the tank 14. The precipitation inhibitor supply unit 12 has a precipitation inhibitor supply source 12a, a precipitation inhibitor supply line 12b, and a flow regulator 12c.

[0058] The precipitation inhibitor supply source 12a is, for example, a tank for storing precipitation inhibitors. A precipitation inhibitor supply line 12b connects the precipitation inhibitor supply source 12a to the tank 14, supplying precipitation inhibitors from the supply source 12a to the tank 14. A flow regulator 12c is installed on the precipitation inhibitor supply line 12b to regulate the flow rate of precipitation inhibitor supplied to the tank 14. The flow regulator 12c consists of an on / off valve, a flow control valve, a flow meter, etc.

[0059] Furthermore, the precipitation inhibitor only needs to contain a component that inhibits the precipitation of silicon oxide. For example, it may contain a component that stabilizes silicon ions dissolved in an aqueous phosphoric acid solution in a dissolved state to inhibit the precipitation of silicon oxide. Alternatively, it may contain a component that inhibits the precipitation of silicon oxide using other known methods.

[0060] The precipitation inhibitor in this embodiment can be, for example, an aqueous solution of hexafluorosilicic acid (H2SiF6) containing fluorine. Additionally, to stabilize the hexafluorosilicic acid in the aqueous solution, additives such as ammonia can be included.

[0061] As an example of an embodiment, precipitation inhibitors such as ammonium hexafluorosilicate ((NH4)2SiF6) and sodium hexafluorosilicate (Na2SiF6) can be used.

[0062] Additionally, the precipitation inhibitor in the implementation method can be a component with an ionic radius ranging from to Compounds of elements with cations. Here, "ionic radius" refers to the radius of the ion obtained empirically from the sum of the radii of the anion and the cation, derived from the lattice constant of the crystal lattice.

[0063] The precipitation inhibitors in the implementation may, for example, comprise oxides of any one of the elements selected from aluminum, potassium, lithium, sodium, magnesium, calcium, zirconium, tungsten, titanium, molybdenum, hafnium, nickel, and chromium.

[0064] In addition, the precipitation inhibitor of the embodiment may replace the oxide of any of the above-mentioned elements or be added thereon, including at least one of the nitride, chloride, bromide, hydroxide and nitrate of any of the above-mentioned elements.

[0065] The precipitation inhibitors in the embodiments may include, for example, at least one of Al(OH)3, AlCl3, AlBr3, Al(NO3)3, Al2(SO4)3, AlPO4, and Al2O3.

[0066] Furthermore, the precipitation inhibitor in the embodiments may include at least one of KCl, KBr, KOH, and KNO3. Also, the precipitation inhibitor in the embodiments may include at least one of LiCl, NaCl, MgCl2, CaCl2, and ZrCl4.

[0067] Tank 14 stores the phosphoric acid aqueous solution supplied from the phosphoric acid aqueous solution supply unit 11 and the precipitation inhibitor supplied from the precipitation inhibitor supply unit 12. In addition, tank 14 stores the mixture M generated by mixing the phosphoric acid aqueous solution and the precipitation inhibitor.

[0068] The upper part of tank 14 is open, and a first liquid level sensor S1 and a second liquid level sensor S2 are sequentially installed from the top. The first liquid level sensor S1 and the second liquid level sensor S2 can be used to control the liquid level of the phosphoric acid aqueous solution and the mixture M stored in tank 14. Furthermore, in this embodiment, the first liquid level sensor S1 and the second liquid level sensor S2 can be used to weigh the volume of the phosphoric acid aqueous solution and the precipitation inhibitor.

[0069] The circulation line 15 is a circulation route that exits from tank 14 and returns to tank 14. The circulation line 15 has an inlet 15a located at the bottom of tank 14 and an outlet 15b located at the top of tank 14, forming a circulating flow from the inlet 15a to the outlet 15b. Furthermore, in this embodiment, the outlet 15b is positioned above the liquid surface of the mixture M stored in tank 14.

[0070] On the circulation line 15, with tank 14 as the reference (upstream), starting from the upstream side, a pump 16, an on / off valve 18, a filter 19, a heater 17 (an example of a heating mechanism), a branch section 15c, and a back pressure valve 51 are arranged in sequence. In addition, a liquid delivery line 22 branches off from the branch section 15c for delivering the mixed liquid M to the processing tank 31 of the substrate processing section 30.

[0071] The liquid delivery line 22 connects from the branch 15c to the inner tank 31a and outer tank 31b of the treatment tank 31. The liquid delivery line 22 has a flow regulator 23. The flow regulator 23 regulates the flow rate of the mixed liquid M supplied to the treatment tank 31. The flow regulator 23 consists of an on / off valve, a flow control valve, a flow meter, etc.

[0072] A thermometer 52 is installed upstream of the branch 22b in the liquid delivery line 22. This thermometer 52 measures the temperature of the mixed liquid M flowing in the liquid delivery line 22. Furthermore, the branch 22b is the location in the liquid delivery line 22 where the liquid delivery line 22c, which connects to the inner tank 31a, and the liquid delivery line 22d, which connects to the outer tank 31b, branch off. That is, the liquid delivery lines 22c and 22d are part of the liquid delivery line 22.

[0073] A valve 53 is installed in the liquid delivery line 22c. From the upstream side, a valve 54, a flow meter 55, a constant pressure valve 56, a throttle valve 57, a branch line 22e, and a valve 58 are sequentially installed in the liquid delivery line 22d. Additionally, a return line 24 branches off from the branch line 22e to return the mixture M to the tank 14. This return line 24 has a valve 59.

[0074] The control unit, described later, opens and closes valves 53 and 54 differently from each other. Thus, the control unit can switch the delivery of the mixture M to either the inner tank 31a or the outer tank 31b.

[0075] Flow meter 55 measures the flow rate of the mixture M flowing in the liquid delivery line 22d. The control unit can correct the flow rate information of the mixture M obtained from the flow meter 55 based on the temperature information of the mixture M obtained from the thermometer 52. Therefore, even if the temperature of the mixture M varies greatly from room temperature to high temperature, the flow rate of the mixture M flowing in the flow meter 55 can be measured with high accuracy.

[0076] The constant pressure valve 56 regulates the pressure downstream of the constant pressure valve 56 in the liquid delivery line 22d. The throttle valve 57 regulates the flow rate of the mixed liquid M flowing in the liquid delivery line 22d.

[0077] The control unit opens and closes valves 58 and 59 differently from each other. Thus, the control unit can switch the flow of the mixture M to either the outer tank 31b or the tank 14.

[0078] Pump 16 can generate a circulating flow of the mixture M that comes out of tank 14, passes through circulation line 15 and returns to tank 14.

[0079] Heater 17 heats the mixture M circulating within circulation line 15. In this embodiment, the mixture M stored in tank 14 is heated by heating the mixture M with heater 17.

[0080] The filter 19 removes contaminants such as particles from the mixture M circulating in the circulation line 15. In addition, a bypass flow path 20 is provided in the circulation line 15 to bypass the filter 19, and an on / off valve 21 is provided in the bypass flow path 20.

[0081] Then, by opening and closing the on / off valve 18 provided in the circulation line 15 and the on / off valve 21 provided in the bypass flow path 20 differently from each other, either the circulating flow through the filter 19 or the circulating flow bypassing the filter 19 can be formed.

[0082] The back pressure valve 51 is located downstream of the branch 15c in the circulation line 15. The back pressure valve 51 is used to regulate the pressure on the upstream side of the circulation line 15 (e.g., the branch 15c) of the back pressure valve 51.

[0083] (Silicone Solution Supply Department)

[0084] The silicon solution supply unit 25 supplies silicon solution to the processing tank 31. The silicon solution in this embodiment is, for example, a solution formed by dispersing colloidal silicon. The silicon solution supply unit 25 includes a silicon solution supply source 25a, a silicon solution supply line 25b, and a flow regulator 25c.

[0085] The silicon solution supply source 25a is, for example, a tank for storing silicon solution. The silicon solution supply line 25b is connected to the inner tank 31a of the processing tank 31. A flow regulator 25c is provided on the silicon solution supply line 25b to regulate the flow rate of the silicon solution flowing in the silicon solution supply line 25b. The flow regulator 25c consists of an on / off valve, a flow control valve, a flow meter, etc.

[0086] (Substrate Processing Department)

[0087] The substrate processing unit 30 includes a processing tank 31, a circulation circuit 32, a DIW supply unit 33, and an etching solution discharge unit 34. The processing tank 31 includes an inner tank 31a and an outer tank 31b.

[0088] The upper part of the inner tank 31a is open, and the etching solution E is supplied to the vicinity of the upper part. In this inner tank 31a, multiple wafers W are immersed in the etching solution E by a substrate lifting mechanism 35 to perform etching on the wafers W. The substrate lifting mechanism 35 is configured to be able to lift and hold the multiple wafers W in a vertical, side-by-side arrangement.

[0089] The outer tank 31b is disposed around the upper part of the inner tank 31a, and is open at the top. Etching solution E overflowing from the inner tank 31a flows into the outer tank 31b.

[0090] In the inner tank 31a and the outer tank 31b, a mixture M is supplied from the mixing device 10 via the liquid delivery line 22. Additionally, in the inner tank 31a, a silicon solution is supplied from the silicon solution supply unit 25 via the silicon solution supply line 25b. Furthermore, in the outer tank 31b, DIW (Deionized Water) is supplied from the DIW supply unit 33.

[0091] The DIW supply unit 33 includes a DIW supply source 33a, a DIW supply line 33b, and a flow regulator 33c. The DIW supply unit 33 supplies DIW to the external tank 31b to replenish the water evaporated from the heated etching solution E.

[0092] The DIW supply line 33b connects the DIW supply source 33a and the outer tank 31b, and supplies DIW at a specified temperature to the outer tank 31b from the DIW supply source 33a.

[0093] A flow regulator 33c is installed on the DIW supply line 33b to regulate the supply of DIW to the external tank 31b. The flow regulator 33c consists of an on / off valve, a flow control valve, and a flow meter. By adjusting the supply of DIW using the flow regulator 33c, the temperature, phosphoric acid concentration, silicon concentration, and precipitation inhibitor concentration of the etching solution E can be adjusted.

[0094] In addition, a temperature sensor 36 and a phosphoric acid concentration sensor 37 are installed in the outer tank 31b. The temperature sensor 36 detects the temperature of the etching solution E, and the phosphoric acid concentration sensor 37 detects the phosphoric acid concentration of the etching solution E. The signals generated by the temperature sensor 36 and the phosphoric acid concentration sensor 37 are sent to the control unit mentioned above.

[0095] The outer tank 31b and the inner tank 31a are connected by a circulation line 32. One end of the circulation line 32 is connected to the bottom of the outer tank 31b, and the other end of the circulation line 32 is connected to the treatment fluid supply nozzle 38 located in the inner tank 31a.

[0096] A pump 39, a filter 41, a heater 40, and a silicon concentration sensor 42 are sequentially arranged in the circulation line 32 starting from the outer tank 31b side.

[0097] Pump 39 forms a circulating flow of etching solution E from outer tank 31b to inner tank 31a via circulation line 32. Additionally, etching solution E overflows from inner tank 31a and flows back to outer tank 31b. As described above, a circulating flow of etching solution E is formed within substrate processing section 30. That is, this circulating flow is formed in outer tank 31b, circulation line 32, and inner tank 31a.

[0098] Heater 40 regulates the temperature of the etchant E circulating in circulation circuit 32. Filter 41 filters the etchant E circulating in circulation circuit 32. Silicon concentration sensor 42 detects the silicon concentration of the etchant E circulating in circulation circuit 32. The signal generated by silicon concentration sensor 42 is sent to the control unit.

[0099] When all or part of the etching solution E used in the etching process is replaced, the etching solution discharge unit 34 discharges the etching solution E containing silicon solution to the discharge unit DR. The etching solution discharge unit 34 has a discharge path 34a, a flow regulator 34b, and a cooling tank 34c.

[0100] Discharge path 34a is connected to circulation path 32. Flow regulator 34b is installed in discharge path 34a to regulate the discharge rate of the etchant E. Flow regulator 34b consists of an on / off valve, a flow control valve, and a flow meter.

[0101] Cooling tank 34c temporarily stores and cools the etching solution E flowing through discharge line 34a. In cooling tank 34c, the discharge rate of etching solution E is regulated by flow regulator 34b.

[0102] (Control Department)

[0103] Although not shown in the diagram here, the substrate processing system 1 also includes a control unit. The control unit controls the operation of each part of the substrate processing system 1 based on signals from switches, various sensors, etc.

[0104] The control unit is, for example, a computer, and has a computer-readable storage medium. The storage medium stores programs for controlling various processes performed in the substrate processing system 1.

[0105] The control unit controls the operation of the substrate processing system 1 by reading and executing a program stored in the storage medium. Furthermore, the program is stored in a computer-readable storage medium and can be installed from other storage media into the control unit's storage medium.

[0106] As a computer-readable storage medium, it includes, for example, hard disk (HD), floppy disk (FD), optical disk (CD), magnetic disk (MO), memory card, etc.

[0107] Then, while referring to Figure 2 The method for adjusting the silicon concentration of the mixture M in the substrate processing system 1 of the embodiment will be explained. Figure 2 This is a flowchart illustrating the steps of the concentration adjustment process in the implementation method.

[0108] Figure 2 The concentration adjustment process shown is performed during the etching process in the substrate processing unit 30, that is, when the wafer W is immersed in the processing tank 31 of the substrate processing unit 30. Specifically, in the concentration adjustment process, a portion of the etchant E with excessive silicon concentration is discharged from the processing tank 31, and a mixing solution M is supplied to the processing tank 31 from the mixing device 10, thereby reducing the silicon concentration of the etchant E in the processing tank 31.

[0109] like Figure 2 As shown, in the substrate processing system 1, a mixing process is first performed (step S101). The mixing process is the process of supplying a phosphoric acid aqueous solution and a precipitation inhibitor to tank 14 to generate a mixture M.

[0110] First, the control unit activates the phosphoric acid aqueous solution supply unit 11 (turns it to the ON state) to supply phosphoric acid aqueous solution to the tank 14 from the phosphoric acid aqueous solution supply source 11a.

[0111] At this moment, the precipitation inhibitor supply unit 12, the silicon solution supply unit 25, the pump 16, and the heater 17 are not operating (in the OFF state). Additionally, at this moment, the on / off valve 18 is closed, and the on / off valve 21 is open. Therefore, the filter 19 is bypassed by the bypass flow path 20 (the filter bypass is open), and the back pressure valve 51 is fully open. Furthermore, at this moment, the flow regulator 23 is closed, and there is no liquid stored in the tank 14. Therefore, OFF signals are output from the first liquid level sensor S1 and the second liquid level sensor S2.

[0112] When a specified amount of phosphoric acid aqueous solution is supplied to tank 14, the control unit activates pump 16 (turns it on), forming a circulating flow in circulation line 15.

[0113] When the level of the phosphoric acid aqueous solution in tank 14 rises to a second height or higher, an ON signal is output from the second liquid level sensor S2. This causes the control unit to activate the precipitation inhibitor supply unit 12 (turning it on), supplying precipitation inhibitor to tank 14 from the precipitation inhibitor supply source 12a. Simultaneously, the control unit deactivates the phosphoric acid aqueous solution supply unit 11 (turning it off).

[0114] Next, when a predetermined amount of precipitation inhibitor is supplied to tank 14, the control unit stops the precipitation inhibitor supply unit 12 (turns it off) and turns on the phosphoric acid aqueous solution supply unit 11 (turns it on) to supply phosphoric acid aqueous solution to tank 14.

[0115] When the liquid level of the mixture M in tank 14 rises to a height above the first level, an open signal is output from the first liquid level sensor S1. This causes the control unit to consider that a predetermined amount of phosphoric acid aqueous solution has been supplied to tank 14, and the phosphoric acid aqueous solution supply unit 11 stops operating (becomes in a closed state). Thus, the mixing process ends.

[0116] As described above, the control unit operates pump 16 before supplying the precipitation inhibitor to tank 14. This allows a circulating flow to be formed in circulation line 15 before the precipitation inhibitor is supplied, thus improving the mixability of the phosphoric acid aqueous solution and the precipitation inhibitor.

[0117] Furthermore, the control unit does not simultaneously supply phosphoric acid aqueous solution and precipitation inhibitor to tank 14, but supplies them separately. This prevents the first liquid level sensor S1 from outputting an open signal before the prescribed amount of precipitation inhibitor is supplied. Therefore, a prescribed amount of precipitation inhibitor can be reliably supplied to tank 14.

[0118] Next, in the substrate processing system 1, a concentration process is performed (step S102). The concentration process is a process that increases the phosphoric acid concentration of the mixture M by concentrating the mixture M generated in step S101.

[0119] First, the control unit activates heater 17 (turns it on) to heat the mixture M circulating in circulation line 15. By heating the mixture M circulating in circulation line 15, the temperature of the mixture M stored in tank 14 rises.

[0120] By heating the mixture M, the water in the mixture M evaporates. This increases the phosphoric acid concentration of the mixture M. The heating temperature of the mixture M during the concentration process is a predetermined temperature that ensures the amount of water evaporated from the mixture M exceeds the amount of moisture absorbed by the mixture M.

[0121] Furthermore, the mixing device 10 may also install a third liquid level sensor at a position lower than the first liquid level sensor S1 and higher than the second liquid level sensor S2. In this case, the control unit can terminate the concentration process by outputting an off signal from the third liquid level sensor. In this case, the liquid level of the mixture M in the tank 14 is a third level, which is lower than the first level and higher than the second level.

[0122] Additionally, the mixing device 10 may include a phosphate concentration meter for measuring the phosphate concentration of the mixture M. The phosphate concentration meter may be installed in the tank 14 or on the circulation line 15. In this case, the control unit can terminate the concentration process when the phosphate concentration measured by the phosphate concentration meter reaches a predetermined value. At this time, when the control unit outputs an off signal from the first liquid level sensor S1, it replenishes the tank 14 with phosphate aqueous solution from the phosphate aqueous solution supply unit 11 until an on signal is output from the first liquid level sensor S1. Thus, the liquid level of the mixture M in the tank 14 can be maintained at a first height.

[0123] Next, in the substrate processing system 1, a concentration maintenance process is performed (step S103). The concentration maintenance process is a process used to maintain the phosphoric acid concentration of the mixture M in tank 14 at the concentration during the concentration process during the standby time until the liquid delivery process described later begins.

[0124] In the concentration maintenance process, the control unit controls the heater 17 to adjust the temperature of the mixture M so that the amount of water evaporated from the mixture M in the tank 14 is close to the amount of moisture absorbed by the mixture M in the tank 14.

[0125] When the mixture M is at room temperature, the amount of moisture absorbed by the mixture M exceeds the amount of moisture evaporated from the mixture M. Therefore, the water content of the mixture M increases, and consequently, the phosphoric acid concentration of the mixture M decreases. On the other hand, during the concentration process, as described above, the amount of moisture evaporated from the mixture M exceeds the amount of moisture absorbed by the mixture M. Therefore, during the concentration maintenance process, the control unit heats the mixture M in tank 14 at a temperature higher than room temperature but lower than that during the concentration process. For example, the control unit heats the mixture M in tank 14 to a temperature of less than 100°C.

[0126] As described above, by adjusting the temperature of the mixture M so that the amount of water evaporation from the mixture M is close to the amount of moisture absorbed by the mixture M, the concentration change of the mixture M in tank 14 can be suppressed. Therefore, in subsequent liquid delivery processing, the mixture M, which has been concentrated to the desired concentration through the concentration process, can be supplied from tank 14 to processing tank 31 while maintaining the desired concentration. Thus, according to the substrate processing system 1, etching processing using an etching solution E containing an aqueous phosphoric acid solution and a silicon solution can be appropriately implemented.

[0127] In the concentration maintenance process, the control unit can heat the mixture M at a temperature that makes the amount of water evaporated equal to the amount of moisture absorbed, which is the same as the amount of water absorbed. This temperature can be obtained in advance through experiments.

[0128] In addition, the control unit can control the heater 17 to heat the mixture M so as to maintain the amount of mixture M in the tank 14 after concentration treatment, so that the amount of water evaporation of mixture M is close to the amount of moisture absorbed by mixture M.

[0129] For example, in one embodiment, the liquid level of the mixture M in the concentrated tank 14 is either a first height corresponding to the first liquid level sensor S1 or a third height corresponding to a third liquid level sensor (not shown). The control unit controls the heater 17 based on signals (on and off signals) from the first liquid level sensor S1 or the third liquid level sensor (not shown), thus maintaining the liquid level of the mixture M in the concentrated tank 14.

[0130] In this case, the mixing device 10 may include a water supply unit that supplies water (e.g., DIW) to the tank 14. When the liquid level of the mixture M in the tank 14 decreases and an off signal is output from the first liquid level sensor S1 or the third liquid level sensor, the control unit supplies water to the tank 14 from the water supply unit until an on signal is output from the first liquid level sensor S1 or the third liquid level sensor. This maintains the amount of mixture M in the concentrated tank 14, and consequently, maintains the phosphoric acid concentration of the mixture M in the concentrated tank 14.

[0131] As described above, by controlling the heater 17 to heat the mixture M so as to maintain the amount of mixture M in the tank 14 after concentration treatment, it is easy to maintain the phosphoric acid concentration of the mixture M.

[0132] Next, in the substrate processing system 1, the discharge process (step S104) and the liquid delivery process (step S105) are performed, for example, in parallel.

[0133] During the discharge process, the control unit opens the flow regulator 34b ( Figure 1 (Refer to) the opening and closing valve to discharge a portion of the etching solution E stored in the processing tank 31.

[0134] Then, in the liquid delivery process, the control unit controls the mixing device 10, the liquid delivery line 22 and the return line 24 to deliver, for example, the same amount of mixed liquid as the etching solution E discharged from the processing tank 31 in the discharge process to the processing tank 31.

[0135] Specifically, the control unit sets the flow regulator 23 to the open state and sets the back pressure valve 51 to the throttling state. Additionally, the control unit changes valve 53 to the closed state and valve 54 to the open state.

[0136] Therefore, the control unit supplies the mixing liquid M to the outer tank 31b of the substrate processing unit from the mixing device 10 via the circulation line 15, the liquid delivery line 22, and the liquid delivery line 22d. By supplying the mixing liquid M to the outer tank 31b instead of the inner tank 31a, compared to the case where the mixing liquid M is directly supplied to the inner tank 31a used for processing the wafer W, it is possible to suppress the abrupt change in the silicon concentration of the etchant E in the inner tank 31a.

[0137] Therefore, the silicon concentration of the etching solution E in the processing tank 31 can always be kept constant or below a specified value. The concentration adjustment process ends when steps S104 and S105 are completed.

[0138] Here, concentration maintenance treatment (step S103) is performed throughout the entire period from the concentration treatment (step S102) until the liquid delivery treatment (step S105) begins. However, concentration maintenance treatment may also be performed during at least a portion of the above-mentioned period.

[0139] (Composition of the mixing device)

[0140] Next, refer to Figure 3 The configuration of the mixing device 10 in the embodiment is explained. Figure 3 This is a diagram showing the configuration of the mixing device 10 according to the embodiment.

[0141] like Figure 3 As shown, the mixing device 10 also includes a receiving section 26, an air supply section 27, and an exhaust section 28. The receiving section 26 is capable of receiving at least the tank 14 from the various structures of the mixing device 10. An FFU (Fan Filter Unit) 26a is provided on the top of the receiving section 26.

[0142] The gas supply unit 27 supplies gas to the interior of the receiving unit 26. Specifically, the gas supply unit 27 includes a gas supply source 27a, a gas supply line 27b, and a flow regulating unit 27c. The gas supply source 27a is, for example, a tank storing dry gases such as N2 gas or dry air. The gas supply line 27b connects the gas supply source 27a to the FFU 26a. Dry gas is supplied from the gas supply source 27a to the interior of the receiving unit 26 via the FFU 26a. The flow regulating unit 27c is, for example, a baffle, capable of regulating the flow rate of the dry gas flowing on the gas supply line 27b.

[0143] As described above, the mixing device 10 can supply dry gas to the interior of the receiving section 26. This suppresses the amount of moisture absorbed by the mixture M. In other words, it suppresses fluctuations in the concentration of the mixture M.

[0144] The exhaust section 28 discharges gas from inside the receiving section 26. Specifically, the exhaust section 28 includes an exhaust line 28a, a flow regulating section 28b, and an exhaust cooling section 28c. The exhaust line 28a connects the interior of the receiving section 26 to the exhaust pipe P of the factory where the mixing device 10 is installed. The flow regulating section 28b is, for example, a baffle, which can regulate the flow rate of the gas flowing on the exhaust line 28a.

[0145] An exhaust cooling unit 28c is provided on the exhaust line 28a to cool the gas flowing in the exhaust line 28a. For example, the exhaust cooling unit 28c is water-cooled, and cooling water flows in a pipe arranged in a coil around the exhaust line 28a to cool the gas flowing in the exhaust line 28a.

[0146] The mixture M in tank 14 is heated during the concentration and concentration maintenance processes, resulting in a higher temperature of the gas discharged from the receiving section 26. When this high-temperature gas is discharged directly to the plant's exhaust pipe P, condensation may occur in the exhaust pipe P. To address this, the mixing unit 10 uses an exhaust cooling section 28c to cool the gas discharged from the receiving section 26, thus suppressing condensation in the plant's exhaust pipe P. Furthermore, the condensate generated in the exhaust cooling section 28c can be discharged from a drainage line provided in the exhaust cooling section 28c to a plant drainage pipe (not shown).

[0147] Next, refer to Figure 4 Explain the adjustment and processing of the gas supply and exhaust volume in the mixing device 10. Figure 4 This is a flowchart illustrating the steps of the gas supply and exhaust volume adjustment process in the mixing device 10 of the embodiment. Figure 4 The air supply and exhaust volume regulation process shown is, for example, with Figure 2 The mixing process shown (step S101) begins simultaneously with or before the mixing process.

[0148] like Figure 4 As shown, during the execution of the mixing and concentration processes, the control unit controls the air supply unit 27 to make the air supply to the receiving unit 26 the first air supply, and controls the exhaust unit 28 to make the exhaust from the receiving unit 26 the first exhaust (step S201).

[0149] Next, the control unit determines whether it is in the process of maintaining concentration (step S202). If it is not in the process of maintaining concentration (step S202, no), the control unit returns the process to step S201 to maintain the first gas supply and the first exhaust volume.

[0150] On the other hand, when it is determined that the concentration maintenance process is underway (step S202, Yes), the control unit controls the gas supply unit 27 to become the second gas supply volume, and controls the exhaust unit 28 to become the second exhaust volume (step S203), and then the gas supply and exhaust volume adjustment process ends. The second gas supply volume is less than the first gas supply volume, and the second exhaust volume is less than the first exhaust volume.

[0151] As described above, the control unit can ensure that the gas supply and exhaust volume, or in other words, the gas exchange volume, during the concentration maintenance process is less than the gas exchange volume during the concentration process. This reduces the contact between the mixture M and the gas within tank 14, thereby further suppressing the moisture absorption of the mixture M.

[0152] <Variation Example>

[0153] In the above embodiments, as an example of the configuration of the mixing device 10, an example is shown where a phosphoric acid aqueous solution and a precipitation inhibitor are supplied separately to the tank 14. However, the mixing device 10 may also supply a mixture M containing a pre-contained phosphoric acid aqueous solution and a precipitation inhibitor to the tank 14.

[0154] In the above embodiments, as an example of an additive, a precipitation inhibitor for suppressing the precipitation of silicon oxide can be listed. However, the additive may also be a silicon compound additive, and it does not necessarily have to be a precipitation inhibitor.

[0155] In the above embodiments, an example was described in which the substrate processing system 1 includes a mixing device 10 and a substrate processing unit 30, that is, an example in which a mixture M is supplied from one mixing device 10 to one substrate processing unit 30. However, the present invention is not limited to this, and the mixture M can also be supplied from one mixing device 10 to multiple substrate processing units 30. That is, the substrate processing system 1 may include more than one mixing device 10 and more than one substrate processing unit 30.

[0156] The control unit can, for example, predict the start time of the next liquid delivery process based on the silicon concentration measured by the silicon concentration sensor 42, and determine the start time of the concentration adjustment process in such a way that the concentration process ends at the predicted start time. This minimizes the standby time from the end of the concentration process to the start of the liquid delivery process, thus suppressing the decrease in the phosphoric acid concentration of the mixture M during this standby time.

[0157] As described above, the storage device of the embodiment (for example, the mixing device 10) includes a storage tank (for example, a tank 14), a heating mechanism (for example, a heater 17), and a control unit. The storage tank is used to store a treatment solution (for example, a mixture M) containing an aqueous phosphoric acid solution and an additive (for example, a precipitation inhibitor). The heater is capable of heating the treatment solution stored in the storage tank. The control unit performs a concentration maintenance process, in which the heating mechanism is controlled to adjust the temperature of the treatment solution so that the amount of water evaporation from the treatment solution in the storage tank is close to the amount of moisture absorbed by the treatment solution in the storage tank. By adjusting the temperature of the treatment solution so that the amount of water evaporation from the treatment solution is close to the amount of moisture absorbed by the mixture M, the concentration change of the treatment solution in the storage tank can be suppressed. As a result, substrate processing can be appropriately carried out.

[0158] The storage device of the embodiment may include a treatment liquid supply unit (for example, a phosphoric acid aqueous solution supply unit 11 and a precipitation inhibitor supply unit 12) for supplying treatment liquid to the storage tank. Furthermore, the control unit may perform the following before concentration maintenance treatment: a storage treatment (for example, a mixing treatment) by controlling the treatment liquid supply unit to store the treatment liquid in the storage tank; and a concentration treatment by controlling the heating mechanism to heat the treatment liquid stored in the storage tank to concentrate it. In this case, by controlling the heating mechanism to heat the treatment liquid during concentration maintenance treatment, the control unit maintains the amount of treatment liquid in the storage tank after concentration treatment, thereby making the water evaporation rate of the treatment liquid in the storage tank close to the moisture absorption rate of the treatment liquid in the storage tank. This makes it easy to maintain the phosphoric acid concentration in the treatment liquid.

[0159] The storage device of the embodiment may include a liquid level detection unit (for example, a first liquid level sensor S1 or a third liquid level sensor) for detecting the liquid level of the processed liquid stored in the storage tank. In this case, the control unit can control the heating mechanism based on the signal from the liquid level detection unit during concentration maintenance processing. As a result, it becomes easy to maintain the phosphoric acid concentration in the processed liquid.

[0160] The control unit performs a concentration maintenance process during at least a portion of the period from the concentration process until the liquid delivery process begins, from when the processing liquid stored in the storage tank is transferred to the processing tank (processing tank 31, for example) for processing the substrate. This allows the processing liquid to be maintained at the desired concentration and supplied from the storage tank to the processing tank.

[0161] The storage device of the embodiment may include: an air supply unit (air supply unit 27, for example) that supplies gas to the space of the storage tank (for example, storage unit 26); and an exhaust unit (exhaust unit 28, for example) that discharges gas from the space. In this case, during the execution of the concentration process, the control unit operates the air supply unit at a first air supply rate and the exhaust unit at a first exhaust rate; during the execution of the concentration maintenance process, the control unit operates the air supply unit at a second air supply rate less than the first air supply rate and the exhaust unit at a second exhaust rate less than the first exhaust rate. By reducing the air supply and exhaust rates during the concentration maintenance process, the amount of moisture absorbed by the treatment liquid can be suppressed. That is, the concentration fluctuation of the treatment liquid can be suppressed.

[0162] The gas supply unit can supply dry gas (for example, N2 gas or dry air) into the space. By supplying dry gas, the hygroscopic absorption of the treatment liquid can be suppressed.

[0163] The exhaust section may include an exhaust cooling section (as an example, exhaust cooling section 28c) for cooling the gas discharged from the space. By including an exhaust cooling mechanism, condensation in the plant equipment connected to the exhaust section can be suppressed, for example.

[0164] The processing liquid supply unit may include a phosphoric acid aqueous solution supply unit (for example, phosphoric acid aqueous solution supply unit 11) that supplies phosphoric acid aqueous solution to the storage tank and an additive supply unit (for example, precipitation inhibitor supply unit 12) that supplies additives to the storage tank.

[0165] The storage device of the embodiment may include a circulation line (as an example, circulation line 15) that allows the treatment liquid stored in the storage tank to be discharged from the storage tank and then returned to the storage tank. In this case, a heating mechanism may be provided on the circulation line.

[0166] The embodiments of the present invention have been described above. However, the present invention is not limited to the embodiments described above. Various modifications can be made as long as they do not depart from the spirit of the invention.

[0167] The embodiments disclosed in this specification are merely illustrative in all respects and should not be considered limiting. In fact, the above-described embodiments can be implemented in various ways. Furthermore, the above-described embodiments can be omitted, substituted, and modified in various ways without departing from the scope and spirit of the present invention.

Claims

1. A storage device, characterized in that, include: Storage tank for storing treatment solutions containing phosphoric acid aqueous solution and additives; A heating mechanism capable of heating the treatment liquid stored in the storage tank; A treatment liquid supply unit that supplies the treatment liquid to the storage tank; and The control unit performs a concentration maintenance process, in which it controls the heating mechanism to adjust the temperature of the treatment solution so that the amount of water evaporation from the treatment solution in the storage tank is close to the amount of moisture absorbed by the treatment solution in the storage tank. Prior to the concentration maintenance treatment, the control unit performs: a storage treatment by controlling the treatment liquid supply unit to store the treatment liquid in the storage tank; and a concentration treatment by controlling the heating mechanism to heat the treatment liquid stored in the storage tank to concentrate it. In the concentration maintenance process, the heating mechanism is controlled to heat the treatment liquid to maintain the amount of treatment liquid in the storage tank after the concentration treatment, so that the amount of water evaporation in the treatment liquid in the storage tank is close to the amount of moisture absorbed by the treatment liquid in the storage tank. The control unit performs the concentration maintenance process during at least a portion of the period from after the concentration process until the start of the liquid delivery process, in which the processing liquid stored in the storage tank is transferred to the processing tank for substrate processing. The control unit controls the heating mechanism to heat the treatment liquid to a temperature during the concentration process, such that the amount of water evaporated from the treatment liquid exceeds the amount of moisture absorbed by the treatment liquid, and during the concentration maintenance process, the treatment liquid is heated to a temperature higher than room temperature but lower than the temperature during the concentration process.

2. The storage device as claimed in claim 1, characterized in that: Includes a liquid level detection unit for detecting the liquid level of the treatment liquid stored in the storage tank. The control unit controls the heating mechanism based on signals from the liquid level detection unit during the concentration maintenance process.

3. The storage device as described in claim 1 or 2, characterized in that, include: A gas supply unit that supplies gas to the space housing the storage tank; and An exhaust section that discharges gas from the space. During the concentration process, the control unit operates the gas supply unit at a first gas supply rate and the exhaust unit at a first exhaust rate. During the concentration maintenance process, the control unit operates the gas supply unit at a second gas supply rate less than the first gas supply rate and the exhaust unit at a second exhaust rate less than the first exhaust rate.

4. The storage device as described in claim 3, characterized in that: The gas supply unit supplies dry gas to the space.

5. The storage device as described in claim 3, characterized in that: The exhaust section includes an exhaust cooling section for cooling the gas discharged from the space.

6. The storage device as described in claim 1 or 2, characterized in that: The processing fluid supply unit includes: A phosphoric acid aqueous solution supply unit that supplies the phosphoric acid aqueous solution to the storage tank; and An additive supply unit that supplies the additive to the storage tank.

7. The storage device as described in claim 1 or 2, characterized in that: This includes a circulation circuit that allows the treated liquid stored in the storage tank to be discharged from the storage tank and then returned to the storage tank. The heating mechanism is located on the circulation line.

8. A storage method, characterized in that, include: The storage step involves storing the treatment solution containing phosphoric acid aqueous solution and additives in a storage tank; The concentration step involves using a heating mechanism capable of heating the processed liquid stored in the storage tank to heat the processed liquid stored in the storage tank, thereby concentrating it; and In the concentration maintenance step, after the concentration step, the heating mechanism is used to adjust the temperature of the processed liquid so that the amount of water evaporated from the processed liquid in the storage tank is close to the amount of moisture absorbed by the processed liquid in the storage tank. and In the liquid delivery step, after the concentration step, the processing liquid stored in the storage tank is transferred to a processing tank for processing the substrate. The concentration maintenance step is performed during at least a portion of the period between the concentration step and the start of the liquid delivery step. In the concentration maintenance step, the heating mechanism is used to heat the processed liquid stored in the storage tank to maintain the amount of processed liquid after the concentration step, so that the amount of water evaporation from the processed liquid in the storage tank is close to the amount of moisture absorbed by the processed liquid in the storage tank. In the concentration step, the treatment liquid is heated to a temperature at which the amount of water evaporated from the treatment liquid exceeds the amount of moisture absorbed by the treatment liquid. In the concentration maintenance treatment, the treatment liquid is heated to a temperature higher than room temperature but lower than the temperature during the concentration step.

9. A storage method, characterized in that, include: The storage step involves feeding an aqueous phosphoric acid solution and additives into a storage tank for mixing, and then storing the resulting treatment solution in the storage tank. and In the concentration step, a heating mechanism capable of heating the processed liquid stored in the storage tank is used to heat the processed liquid stored in the storage tank to concentrate it; In the concentration maintenance step, after the concentration step, the heating mechanism is used to adjust the temperature of the processed liquid so that the amount of water evaporated from the processed liquid in the storage tank is close to the amount of moisture absorbed by the processed liquid in the storage tank. and In the liquid delivery step, after the concentration step, the processing liquid stored in the storage tank is transferred to a processing tank for processing the substrate. The concentration maintenance step is performed during at least a portion of the period between the concentration step and the start of the liquid delivery step. In the concentration maintenance step, the heating mechanism is used to heat the processed liquid stored in the storage tank to maintain the amount of processed liquid after the concentration step, so that the amount of water evaporation from the processed liquid in the storage tank is close to the amount of moisture absorbed by the processed liquid in the storage tank. Using the heating mechanism, in the concentration step, the treatment liquid is heated to a temperature at which the amount of water evaporated from the treatment liquid exceeds the amount of moisture absorbed by the treatment liquid, and in the concentration maintenance step, the treatment liquid is heated to a temperature higher than room temperature but lower than the temperature during the concentration step.

10. The storage method as described in claim 8 or 9, characterized in that: It also includes a gas supply and exhaust step, in which a gas supply unit supplies gas to the space where the storage tank is located and an exhaust unit discharges gas from the space, thereby supplying and exhausting gas into and out of the space. In the gas supply and exhaust steps, in the concentration step, the gas supply unit operates at a first gas supply rate and the exhaust unit operates at a first exhaust rate; in the concentration maintenance step, the gas supply unit operates at a second gas supply rate less than the first gas supply rate and the exhaust unit operates at a second exhaust rate less than the first exhaust rate.

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