Substrate Processing Equipment

Abstract

To provide a substrate processing device capable of preventing a silicon concentration of a phosphoric acid solution supplied to a processing unit from being high.SOLUTION: A quartz heater 41 including a quartz pipe 47 is provided in concentration piping 39 which is a part of first circulation piping 35. Both ends 36A and 36B of first detour piping 36 are connected to an upstream end and a downstream end of the condensation piping 39. A non-quartz heater 45 including a non-quartz pipe 51 is provided in the first detour piping 36. When condensing a phosphoric acid solution in a first tank T1, a control unit 93 heats the phosphoric acid solution passing the condensation piping 39 using the quartz heater 41 while feeding the phosphoric acid solution to the condensation piping 39. When the condensation of the phosphoric acid solution in the first tank T1 is completed, the control unit 93 heats the phosphoric acid solution passing the first detour piping 36 using the non-quartz heater 45 while feeding the phosphoric acid solution to the first detour piping 36.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a substrate processing apparatus for processing substrates. Examples of the substrate include semiconductor substrates, FPD (Flat Panel Display) substrates, photomask glass substrates, optical disk substrates, magnetic disk substrates, ceramic substrates, and solar cell substrates. Examples of the FPD include liquid crystal display devices and organic EL (electroluminescence) display devices. [Background technology]

[0002] A conventional substrate processing apparatus includes a processing tank, an outer tank, and a circulation line (see, for example, Patent Document 1). The processing tank stores a phosphoric acid solution. Substrates are processed by immersing them in the phosphoric acid solution in the processing tank. The outer tank is provided on the outer periphery of the processing tank and receives the phosphoric acid solution that overflows from the processing tank. The circulation line is configured to return the phosphoric acid solution discharged from the outer tank to the processing tank. The circulation line is provided with a circulation pump and a temperature controller.

[0003] The substrate processing apparatus also includes a preliminary temperature adjustment unit. The preliminary temperature adjustment unit includes a container for storing a phosphoric acid solution (processing liquid). This container is supplied with phosphoric acid (phosphoric acid solution) from a chemical supply source, or with pure water. The phosphoric acid solution supplied into the container is temperature-adjusted while being circulated. The temperature-adjusted phosphoric acid solution is then supplied to the processing tank via an outer tank and a circulation line.

[0004] For example, 3D-NAND devices are a type of nonvolatile memory. In the manufacturing process of these devices, a structure in which silicon nitride films and silicon oxide films are alternately stacked is formed on a substrate. The silicon nitride films are then selectively etched using a phosphoric acid solution.

[0005] By adding silicon to the phosphoric acid solution, the etching rate of the phosphoric acid solution for silicon nitride films can be made higher than that for silicon oxide films. In other words, when the silicon concentration in the phosphoric acid solution is within an appropriate range, the etching rate of the phosphoric acid solution for silicon oxide films is kept sufficiently lower than the etching rate for silicon nitride films. As a result, the silicon nitride films on the substrate are selectively etched (see, for example, Patent Documents 2 and 3). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2018-050001 [Patent Document 2] Japanese Patent Publication No. 2020-088003 [Patent Document 3] Japanese Patent Application Laid-Open No. 2015-177139 Summary of the Invention [Problem to be solved by the invention]

[0007] However, conventional substrate processing apparatuses have the following problem. The silicon concentration of the phosphoric acid solution supplied from the preliminary temperature adjustment unit is assumed to be 0 (zero) ppm or a concentration close to 0 ppm. However, the inventors have confirmed that the silicon concentration of the phosphoric acid solution supplied from the preliminary temperature adjustment unit is higher than expected. The substrate processing apparatus supplies the phosphoric acid solution to a processing section (e.g., a processing tank) based on the assumption that the silicon concentration of the phosphoric acid solution is 0 ppm or a concentration close to 0 ppm. Nevertheless, if the silicon concentration is actually high, the processing may be affected, for example, by continuing to supply a larger amount of phosphoric acid solution than expected from the preliminary temperature adjustment unit.

[0008] The present invention has been made in consideration of the above circumstances, and aims to provide a substrate processing apparatus that can prevent the silicon concentration in the phosphoric acid solution supplied to the processing section from becoming high. [Means for solving the problem]

[0009] As a result of intensive research into solving the above problem, the inventors discovered that silicon elutes from the quartz parts of the heater, causing the silicon concentration to increase.

[0010] The present invention based on this finding has the following configuration: That is, a substrate processing apparatus according to the present invention includes a processing section having a processing tank for storing a phosphoric acid solution for immersing a substrate, a tank for storing the phosphoric acid solution, a supply flow path for sending the phosphoric acid solution in the tank to the processing section, a circulation flow path having both ends connected to the tank and for returning the phosphoric acid solution flowing from the tank to the tank, a pump provided in the circulation flow path, a quartz heater provided in a concentration flow path which is a part of the circulation flow path, the quartz heater being made of quartz and having a quartz tube for passing the phosphoric acid solution, a bypass flow path having both ends connected to the upstream end and downstream end of the concentration flow path, and a pump provided in the bypass flow path. and a control unit, wherein when concentrating the phosphoric acid solution in the tank, the control unit uses the quartz heater to heat the phosphoric acid solution passing through the concentration flow path while sending the phosphoric acid solution to the concentration flow path, and when concentration of the phosphoric acid solution in the tank is completed, the control unit uses the non-quartz heater to heat the phosphoric acid solution passing through the bypass flow path while sending the phosphoric acid solution to the bypass flow path, thereby maintaining the temperature of the phosphoric acid solution in the tank.

[0011] In a substrate processing apparatus according to the present invention, a quartz heater is provided in a concentration flow path, which is part of a circulation flow path, and a non-quartz heater is provided in a bypass flow path that bypasses the quartz heater. When concentrating the phosphoric acid solution in the tank, the quartz heater is used to heat the phosphoric acid solution passing through the concentration flow path. When the concentration of the phosphoric acid solution in the tank is completed and the temperature of the phosphoric acid solution in the tank is maintained, the non-quartz heater is used to heat the phosphoric acid solution passing through the bypass flow path. When a non-quartz heater is used, elution of silicon into the phosphoric acid solution is prevented, and overall elution of silicon into the phosphoric acid solution is reduced. Therefore, it is possible to prevent the silicon concentration of the phosphoric acid solution supplied to the processing unit from becoming high.

[0012] In addition, the substrate processing apparatus described above preferably further comprises a phosphoric acid concentration sensor for measuring the concentration of the phosphoric acid solution in the tank, and the control unit concentrates the phosphoric acid solution in the tank when the concentration value measured by the phosphoric acid concentration sensor is smaller than a predetermined threshold, and the control unit determines that the concentration of the phosphoric acid solution in the tank is complete and maintains the temperature of the phosphoric acid solution in the tank when the concentration value measured by the phosphoric acid concentration sensor is equal to or greater than the threshold. This allows switching between heating with a quartz heater and heating with a non-quartz heater based on the concentration value measured by the phosphoric acid concentration sensor.

[0013] In the substrate processing apparatus described above, it is preferable that, when concentrating the phosphoric acid solution in the tank, the control unit uses the quartz heater to heat the phosphoric acid solution passing through the concentration flow path so that the temperature of the phosphoric acid solution in the tank reaches a predetermined first temperature, and, when maintaining the temperature of the phosphoric acid solution in the tank, the control unit uses the non-quartz heater to heat the phosphoric acid solution passing through the bypass flow path so that the temperature of the phosphoric acid solution in the tank reaches a second temperature lower than the first temperature. This reduces the output of the non-quartz heater, thereby preventing damage to the non-quartz tube.

[0014] In the above substrate processing apparatus, the first temperature is preferably equal to or higher than the boiling point of the phosphoric acid solution, which can further promote concentration.

[0015] In the substrate processing apparatus described above, the second temperature is preferably 100°C or higher and lower than the boiling point of the phosphoric acid solution. If the temperature of the phosphoric acid solution falls below 100°C, the phosphoric acid solution will absorb moisture. By setting the temperature of the phosphoric acid solution to 100°C or higher, moisture absorption by the phosphoric acid solution can be prevented.

[0016] In the substrate processing apparatus described above, it is preferable to further include a supply passage heater provided in the supply passage for heating the phosphoric acid solution passing through the supply passage, so that when the temperature of the phosphoric acid solution supplied to the processing section through the supply passage is lower than the temperature of the phosphoric acid solution in the processing tank of the processing section, the temperature difference can be suppressed.

[0017] Preferably, the substrate processing apparatus further includes a bubble supply unit disposed on a bottom wall side of the tank, the bubble supply unit having a plurality of holes and configured to supply bubbles into the tank through the plurality of holes, thereby facilitating the concentration of the phosphoric acid solution.

[0018] In the substrate processing apparatus described above, it is preferable that the control unit supplies the phosphoric acid solution to the processing unit through the supply passage when the substrate is being processed by immersing it in the processing bath, thereby gradually replacing the phosphoric acid solution in the processing bath and suppressing an increase in silicon concentration in the phosphoric acid solution in the processing bath.

[0019] In the substrate processing apparatus described above, it is preferable that, during substrate processing in which the substrate is immersed in the processing bath, the control unit supplies the phosphoric acid solution to the processing unit through the supply passage while discharging a portion of the phosphoric acid solution from the processing bath, thereby partially replacing the phosphoric acid solution in the processing bath and relatively significantly reducing the silicon concentration of the phosphoric acid solution.

[0020] In the substrate processing apparatus described above, the non-quartz tube is, for example, a fluororesin tube formed of a fluororesin, which can prevent silicon from being eluted from the heater component into the phosphoric acid solution.

[0021] The substrate processing apparatus further includes a second tank disposed in a supply flow path for sending the phosphoric acid solution from the tank to the processing section and storing the phosphoric acid solution sent from the tank, a second circulation flow path connected at both ends to the second tank and returning the phosphoric acid solution flowing from inside the second tank to the second tank, a second pump disposed in the second circulation flow path, a second quartz heater disposed in a second concentration flow path which is a part of the second circulation flow path, the second quartz heater being made of quartz and having a second quartz tube for passing the phosphoric acid solution, a second bypass flow path connected at both ends to an upstream end and a downstream end of the second concentration flow path, and a pump disposed in the second bypass flow path. and a second non-quartz heater attached to the second tank, the second non-quartz heater having a second non-quartz tube that is not made of quartz for passing the phosphoric acid solution, wherein when concentrating the phosphoric acid solution in the second tank, the control unit uses the second quartz heater to heat the phosphoric acid solution passing through the second concentration flow path while sending the phosphoric acid solution to the second concentration flow path, and when concentration of the phosphoric acid solution in the second tank is completed, the control unit uses the second non-quartz heater to heat the phosphoric acid solution passing through the second bypass flow path while sending the phosphoric acid solution to the second bypass flow path, thereby maintaining the temperature of the phosphoric acid solution in the second tank.

[0022] When the concentration of the phosphoric acid solution in the second tank is completed and the temperature of the phosphoric acid solution in the second tank is maintained, the phosphoric acid solution passing through the second bypass flow path is heated using the second non-quartz heater. When the second non-quartz heater is used, the dissolution of silicon into the phosphoric acid solution is prevented, and the dissolution of silicon into the phosphoric acid solution is reduced overall. Therefore, it is possible to prevent the silicon concentration in the phosphoric acid solution supplied to the processing section from becoming high.

[0023] Furthermore, the above-mentioned substrate processing apparatus preferably includes: a second tank interposed in a supply flow path for sending the phosphoric acid solution from the tank to the processing section, the second tank storing the phosphoric acid solution sent from the tank; a second circulation flow path connected to the second tank at both ends, for returning the phosphoric acid solution flowing from the second tank to the second tank; a second pump provided in the second circulation flow path; and a second quartz heater provided in the second circulation flow path, the second quartz heater being made of quartz and having a second quartz tube for passing the phosphoric acid solution. When concentrating the phosphoric acid solution in the tank, the control unit preferably uses the quartz heater to heat the phosphoric acid solution passing through the concentration flow path so that the temperature of the phosphoric acid solution in the tank becomes a predetermined first temperature, and the control unit preferably uses the second quartz heater to heat the phosphoric acid solution passing through the second circulation flow path so that the temperature of the phosphoric acid solution in the second tank becomes a second temperature lower than the first temperature, thereby maintaining the temperature of the phosphoric acid solution in the second tank.

[0024] Furthermore, the above-mentioned substrate processing apparatus preferably includes: a second tank interposed in a supply flow path for sending the phosphoric acid solution from the tank to the processing part, the second tank storing the phosphoric acid solution sent from the tank; a second circulation flow path connected to the second tank at both ends, for returning the phosphoric acid solution flowing from the second tank to the second tank; a second pump provided in the second circulation flow path; and a second quartz heater provided in the second circulation flow path, the second quartz heater being made of quartz and having a second quartz tube for passing the phosphoric acid solution. When concentrating the phosphoric acid solution in the second tank, the control part preferably uses the second quartz heater to heat the phosphoric acid solution passing through the second circulation flow path so that the temperature of the phosphoric acid solution in the second tank becomes a predetermined first temperature. When concentration of the phosphoric acid solution in the second tank is completed, the control part preferably uses the second quartz heater to heat the phosphoric acid solution passing through the second circulation flow path so that the temperature of the phosphoric acid solution in the second tank becomes a second temperature lower than the first temperature.

[0025] After the concentration of the phosphoric acid solution is completed, the temperature of the phosphoric acid solution is maintained at a second temperature lower than the first temperature set during the concentration of the phosphoric acid solution. By lowering the heating temperature of the second quartz heater, it is possible to suppress the elution of silicon from the second quartz tube of the second quartz heater. As a result, the elution of silicon into the phosphoric acid solution is reduced overall. This makes it possible to prevent the silicon concentration in the phosphoric acid solution supplied to the processing unit from becoming high.

[0026] The substrate processing apparatus according to the present invention further comprises: phosphoric acid solution a tank for storing the phosphoric acid solution; a supply flow path for sending the phosphoric acid solution in the tank to the processing part; a circulation flow path connected at both ends to the tank for returning the phosphoric acid solution flowing from the tank to the tank; a pump provided in the circulation flow path; a quartz heater provided in the circulation flow path, the quartz heater being made of quartz and having a quartz tube through which the phosphoric acid solution passes; and a control part, wherein when concentrating the phosphoric acid solution in the tank, the control part uses the quartz heater to heat the phosphoric acid solution passing through the circulation flow path so that the temperature of the phosphoric acid solution in the tank becomes a predetermined first temperature, and when concentration of the phosphoric acid solution in the tank is completed, the control part uses the quartz heater to heat the phosphoric acid solution passing through the circulation flow path so that the temperature of the phosphoric acid solution in the tank becomes a second temperature lower than the first temperature.

[0027] According to the substrate processing apparatus of the present invention, when concentrating the phosphoric acid solution in the tank, the phosphoric acid solution passing through the circulation flow path is heated using a quartz heater so that the temperature of the phosphoric acid solution in the tank becomes a first temperature. When the concentration of the phosphoric acid solution in the tank is completed and the temperature of the phosphoric acid solution in the tank is maintained, the phosphoric acid solution passing through the circulation flow path is heated using a quartz heater so that the temperature of the phosphoric acid solution in the tank becomes a second temperature lower than the first temperature. Although a quartz heater is used, by raising the temperature to the second temperature lower than the first temperature, less silicon is eluted into the phosphoric acid solution at the second temperature than the first temperature. This prevents the silicon concentration in the phosphoric acid solution supplied to the processing unit from becoming too high. [Effects of the Invention]

[0028] According to the substrate processing apparatus of the present invention, it is possible to prevent the silicon concentration in the phosphoric acid solution supplied to the processing section from becoming high. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 is a diagram showing a substrate processing apparatus according to first and second embodiments. [Figure 2] FIG. [Figure 3] FIG. 1(a) is a diagram showing a quartz heater, and FIG. 1(b) is a diagram showing a non-quartz heater. [Figure 4] 4 is a flowchart illustrating the operation of the auxiliary temperature adjustment unit according to the first embodiment. [Figure 5] 10 is a flowchart illustrating the operation of the auxiliary temperature adjustment unit according to the second embodiment. [Figure 6] FIG. 10 is a diagram showing a substrate processing apparatus according to a third embodiment. [Figure 7] 10 is a flowchart illustrating the operation of the auxiliary temperature adjustment unit according to the third embodiment. [Figure 8] FIG. 10 is a diagram showing the relationship between the predicted silicon concentration and the temperature adjustment time. [Figure 9] FIG. 10 is a diagram showing a substrate processing apparatus according to a fourth embodiment. [Figure 10]10 is a flowchart illustrating the operation of the auxiliary temperature adjustment unit according to the fourth embodiment. [Figure 11] FIG. 10 is a diagram showing a substrate processing apparatus according to a fifth embodiment. [Figure 12] 10 is a flowchart illustrating the operation of the auxiliary temperature adjustment unit according to the fifth embodiment. Example 1

[0030] A first embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a diagram showing a substrate processing apparatus 1. Fig. 2 is a diagram showing a processing section 2A (2B / 2C).

[0031] (1) Configuration of the substrate processing apparatus 1 Referring to Fig. 1, the substrate processing apparatus 1 is a batch-type apparatus that processes a plurality of (e.g., 50) substrates W at once. The substrate processing apparatus 1 includes three processing sections 2A, 2B, and 2C and a backup temperature adjustment unit 4. Note that the number of processing sections is not limited to three.

[0032] The configuration of processing section 2A will be described. Each of the two processing sections 2B and 2C has the same configuration as processing section 2A. See Figure 2. Processing section 2A includes a processing tank 6, an outer tank 7, a tank heater 8, a processing section circulation flow path 9, and a lifter (substrate holder) 11.

[0033] Treatment tank 6 is a container that stores phosphoric acid solution. The phosphoric acid solution is a solution containing phosphoric acid and pure water. Outer tank 7 is provided around treatment tank 6. Outer tank 7 is a container that receives phosphoric acid solution that overflows from treatment tank 6. Outer tank 7 is connected to discharge pipe 14. When the water level of the phosphoric acid solution in outer tank 7 reaches or exceeds the height of inlet 14A of discharge pipe 14, the phosphoric acid solution in outer tank 7 flows out into discharge pipe 14.

[0034] Tank heater 8 is provided on the outer walls of treatment tank 6 and outer tank 7. Tank heater 8 heats the phosphoric acid solution in treatment tank 6 and outer tank 7 from outside of treatment tank 6 and outer tank 7. Tank heater 8 and heater 19, which will be described later, heat the phosphoric acid solution in treatment tank 6 so that the temperature of the phosphoric acid solution reaches a preset temperature (e.g., 160°C).

[0035] The treatment section circulation flow path 9 is formed of, for example, piping. The treatment section circulation flow path 9 connects the outer bath 7 and the treatment bath 6. Specifically, the treatment section circulation flow path 9 connects the bottom of the outer bath 7 to a spray pipe 15 provided at the bottom of the treatment bath 6. The spray pipe 15 has a spray outlet for spraying the phosphoric acid solution. The treatment section circulation flow path 9 returns the phosphoric acid solution that has flowed in from the outer bath 7 to the treatment bath 6 via the spray pipe 15. In addition, the treatment section circulation flow path 9 is provided with, in order from the outer bath 7 side, a pump 17, a heater 19, a filter 21, and a silicon concentration sensor 23.

[0036] A pump 17 pumps the phosphoric acid solution through the treatment section circulation flow path 9. A heater 19 heats the phosphoric acid solution passing through the treatment section circulation flow path 9. A filter 21 removes particles from the phosphoric acid solution that is returned to the treatment tank 6. A silicon concentration sensor 23 measures the silicon concentration of the phosphoric acid solution passing through the treatment section circulation flow path 9.

[0037] The lifter 11 holds a plurality of substrates W to be processed in an upright position at equal intervals. The lifter 11 includes a back plate 11A and a plurality (three) of support portions 11B fixed to the lower part of the back plate 11A. The support portions 11B are configured to be parallel to each other and extend horizontally. The support portions 11B hold a plurality of substrates W.

[0038] The processing unit 2A also includes a plurality of bubble supply pipes 25, a gas supply source 27, supply pipes 28, and an on-off valve V21. Each bubble supply pipe 25 is provided at or near the bottom of the processing tank 6. Each bubble supply pipe 25 has a plurality of holes through which bubbles are supplied into the phosphoric acid solution. This allows the bubbles to enter between the two substrates W, facilitating replacement of the phosphoric acid solution between the two substrates W. Gas (an inert gas such as nitrogen) from the gas supply source 27 is sent to the plurality of bubble supply pipes 25 through the supply pipes 28. The on-off valve V21 starts and stops the supply of gas.

[0039] A discharge pipe 30 is connected to the bottom of the treatment tank 6. An on-off valve V22 is provided on the discharge pipe 30. The discharge pipe 30 discharges the phosphoric acid solution in the treatment tank 6. The on-off valve V22 starts and stops the discharge of the phosphoric acid solution.

[0040] Treatment unit 2A is equipped with a temperature sensor TS11 that measures the temperature of the phosphoric acid solution in treatment tank 6. Treatment unit 2A controls tank heater 8 and heater 19 so that the temperature measured by temperature sensor TS11 becomes a preset temperature (160°C). Treatment tank 6 may be configured to be directly supplied with at least one of an unconcentrated phosphoric acid solution and deionized water (DIW). Treatment unit 2A may also be equipped with a phosphoric acid concentration sensor that measures the phosphoric acid concentration in the phosphoric acid solution in treatment tank 6, outer tank 7, or treatment unit circulation flow path 9.

[0041] (1-1) Configuration of backup temperature control unit 4 Returning to FIG. 1, the preliminary temperature adjustment unit 4 supplies phosphoric acid solution to each of the processing sections 2A, 2B, and 2C. The preliminary temperature adjustment unit 4 includes a preliminary circulation section 31 and a main circulation section 33. Phosphoric acid solutions generally available on the market have a phosphoric acid concentration of 85% at room temperature. The preliminary circulation section 31 heats the phosphoric acid solution with a phosphoric acid concentration of 85%. This evaporates water from the phosphoric acid solution, concentrating the phosphoric acid concentration to 88-89%. The main circulation section 33 stabilizes the phosphoric acid concentration and the temperature of the phosphoric acid solution. First, the configuration of the preliminary circulation section 31 will be described.

[0042] The preliminary circulation section 31 includes a first tank T1, a first circulation pipe 35, a first bypass pipe 36, and a first supply pipe 37. The first circulation pipe 35 corresponds to the circulation flow path of the present invention. The first bypass pipe 36 corresponds to the bypass flow path of the present invention.

[0043] The first tank T1 is a container for storing phosphoric acid solution. The first tank T1 and a second tank T2 (described later) are configured to be degassable. The first tank T1 has an outlet OL1 and an inlet IL1. The outlet OL1 is located at the bottom of the first tank T1, and the inlet IL1 is located at the ceiling of the first tank T1.

[0044] Both ends 35A, 35B of the first circulation pipe 35 are connected to the first tank T1. Specifically, the first end 35A of the first circulation pipe 35 is connected to the outlet OL1 of the first tank T1, and the second end 35B of the first circulation pipe 35 is connected to the inlet IL1 of the first tank T1. The first circulation pipe 35 is a pipe for returning the phosphoric acid solution that has flowed in from inside the first tank T1 to the first tank T1.

[0045] The concentration pipe 39 is part of the first circulation pipe 35. Two quartz heaters 41 (41A, 41B) arranged in series are provided in the concentration pipe 39. A first pump 43 is provided in the first circulation pipe 35 between the outlet OL1 and the quartz heater 41A. The first pump 43 delivers the phosphoric acid solution.

[0046] The first bypass pipe 36 bypasses the two quartz heaters 41. A first end 36A of the first bypass pipe 36 is connected to the first circulation pipe 35 between the first pump 43 and the quartz heater 41A. A second end 36B of the first bypass pipe 36 is connected to the first circulation pipe 35 between the quartz heater 41B and a branch pipe 35C, which will be described later. The first circulation pipe 35 between the first end 36A and the second end 36B is the concentration pipe 39. Therefore, both ends 36A, 36B of the first bypass pipe 36 are connected to the upstream end and downstream end of the concentration pipe 39.

[0047] A non-quartz heater 45 is provided in the first bypass pipe 36. Here, the configurations of the quartz heater 41 and the non-quartz heater 45 will be described with reference to FIGS. 3(a) and 3(b). FIG. 3(a) is a diagram showing the quartz heater 41. The quartz heater 41 includes a quartz tube 47 and a heater body 49. The quartz tube 47 is disposed midway along the concentration pipe 39. The quartz tube 47 is used to pass the phosphoric acid solution. The quartz tube 47 is made of quartz. A hollow cylindrical heater body 49 is provided around the quartz tube 47. The heater body 49 and a heater body 53, which will be described later, are formed, for example, from electric heaters having nichrome wire. The quartz heater 41 heats the phosphoric acid solution passing through the concentration pipe 39 (specifically, the quartz tube 47).

[0048] FIG. 3(b) illustrates the non-quartz heater 45. The non-quartz heater 45 includes a non-quartz tube 51 and a heater body 53. The non-quartz tube 51 is disposed midway through the first bypass piping 36. The non-quartz tube 51 allows the phosphoric acid solution to pass through. The non-quartz tube 51 is not made of quartz. That is, the non-quartz tube 51 is made of a fluorine-based resin such as PFA (perfluoroalkoxyalkane) or PTFE (polytetrafluoroethylene). Therefore, the non-quartz tube 51 is a fluorine-based resin tube. This prevents silicon from eluting from the heater components into the phosphoric acid solution. A hollow cylindrical heater body 53 is provided around the non-quartz tube 51. The non-quartz heater 45 heats the phosphoric acid solution passing through the first bypass piping 36 (specifically, the non-quartz tube 51).

[0049] The concentration pipe 39 corresponds to the concentration flow path of the present invention. The quartz heater 41 corresponds to the quartz heater of the present invention. The quartz tube 47 corresponds to the quartz tube of the present invention. The non-quartz heater 45 corresponds to the non-quartz heater of the present invention. The non-quartz tube 51 corresponds to the non-quartz heater of the present invention.

[0050] Returning to FIG. 1, a branch pipe 35C is provided in the first circulation pipe 35 between the quartz heater 41B and the inlet IL1. The first supply pipe 37 is a pipe for sending the phosphoric acid solution from the first tank T1 to the second tank T2 of the main circulation section 33. A first end of the first supply pipe 37 is connected to the branch pipe 35C. A second end of the first supply pipe 37 is inserted into the second tank T2 and is positioned near the bottom wall of the second tank T2.

[0051] The standby temperature control unit 4 also includes a phosphoric acid supply source 55, a pipe 56, a pump 57, and an on-off valve V1. The phosphoric acid supply source 55 is formed, for example, from a container. A first end of the pipe 56 is connected to the phosphoric acid supply source 55. A second end of the pipe 56 is inserted into the first tank T1 and is disposed near the bottom wall of the first tank T1. A sulfuric acid solution with a phosphoric acid concentration of 85% is supplied from the phosphoric acid supply source 55 to the first tank T1 at room temperature. The pipe 56 is provided with a pump 57 for supplying the phosphoric acid solution and an on-off valve V1. The on-off valve V1 starts and stops the supply of the phosphoric acid solution.

[0052] The standby temperature control unit 4 also includes a deionized water supply source 59, two pipes 61 and 62, a pump 64, and two on-off valves V2 and V3. The deionized water supply source 59 is formed, for example, from a container. A first end of the pipe 61 is connected to the deionized water supply source 59. A second end of the pipe 61 is inserted into the first tank T1 and disposed near the bottom wall of the first tank T1. The pipe 61 is provided with a pump 64 for supplying deionized water (DIW) and an on-off valve V2. A branch pipe 65 is provided in the pipe 61 between the pump 64 and the on-off valve V2. A first end of the pipe 62 is connected to the branch pipe 65. A second end of the pipe 62 is inserted into the second tank T2 and disposed near the bottom wall of the second tank T2. The pipe 62 is provided with an on-off valve V3. The on-off valve V2 starts and stops the supply of deionized water to the first tank T1. The on-off valve V3 starts and stops the supply of pure water to the second tank T2.

[0053] The preliminary circulation section 31 also includes four on-off valves V4, V5, V6, and V7. The on-off valve V4 is provided in the concentration pipe 39 between the first end 36A of the first bypass pipe 36 and the quartz heater 41A. The on-off valve V5 is provided in the first bypass pipe 36 between the first end 36A and the non-quartz heater 45. The on-off valve V6 is provided in the first circulation pipe 35 between the branch pipe 35C and the inlet IL1. The on-off valve V7 is provided in the first supply pipe 37.

[0054] The preliminary circulation section 31 opens the on-off valves V4 and V6, closes the on-off valves V5 and V7, and drives the first pump 43. This circulates the phosphoric acid solution through the outlet OL1, the first pump 43, the two quartz heaters 41, the branch pipe 35C, and the inlet IL1, in that order. The preliminary circulation section 31 also opens the on-off valves V5 and V6, closes the on-off valves V4 and V7, and drives the first pump 43. This circulates the phosphoric acid solution through the outlet OL1, the first pump 43, the non-quartz heater 45, the branch pipe 35C, and the inlet IL1, in that order. The preliminary circulation section 31 opens the on-off valves V5 and V7, closes the on-off valves V4 and V6, and drives the first pump 43. As a result, the phosphoric acid solution flows in the order of outlet OL1, first pump 43, non-quartz heater 45, branch pipe 35C, first supply pipe 37, and "second tank T2."

[0055] When supplying the phosphoric acid solution to the second tank T2, the phosphoric acid solution may be passed through the concentration pipe 39 provided with two quartz heaters 41. That is, the preliminary circulation section 31 may open the on-off valves V4 and V7, close the on-off valves V5 and V6, and drive the first pump 43.

[0056] The preliminary circulation section 31 also includes a bubble supply unit 67, a gas supply source 69, a supply pipe 71, and an on-off valve V8. The bubble supply unit 67 is composed of, for example, multiple pipes. The bubble supply unit 67 has multiple holes that supply bubbles into the phosphoric acid solution in the first tank T1. The bubble supply unit 67 is disposed on the bottom wall side of the first tank T1. The gas supply source 69 is composed of, for example, a container. Gas (for example, an inert gas such as nitrogen) supplied from the gas supply source 69 is sent to the bubble supply unit 67 via the supply pipe 71. The on-off valve V8 starts and stops the supply of bubbles from the bubble supply unit 67.

[0057] The preliminary circulation section 31 also includes a temperature sensor TS1, a phosphoric acid concentration sensor PS1, and a liquid level sensor LS1. The temperature sensor TS1 measures the temperature of the phosphoric acid solution in the first tank T1. The phosphoric acid concentration sensor PS1 measures the phosphoric acid concentration of the phosphoric acid solution in the first tank T1. The phosphoric acid concentration sensor PS1 includes a detection tube 74 and a pressure sensor 75. The pressure sensor 75 measures the pressure of the inert gas (e.g., nitrogen gas) in the detection tube 74, to which a constant flow rate of inert gas is supplied. The phosphoric acid concentration sensor PS1 calculates the phosphoric acid concentration from the measured pressure based on the correlation between pressure and specific gravity and the correlation between specific gravity and concentration. The liquid level sensor LS1 detects the liquid level of the phosphoric acid solution in the first tank T1.

[0058] Next, the main circulation section 33 will be described. The main circulation section 33 includes a second tank T2, a second circulation pipe 77, a second bypass pipe 78, and three second supply pipes 80, 81, and 82. The second tank T2 is a container for storing phosphoric acid solution. The second tank T2 is interposed between the first supply pipe 37 for sending the phosphoric acid solution from the first tank T1 to, for example, the treatment section 2A and, for example, the second supply pipe 80, and stores the phosphoric acid solution sent from the first tank T1. The second tank T2 includes an outlet OL2 and an inlet IL2. The outlet OL2 is provided at the bottom of the second tank T2, and the inlet IL2 is provided at the ceiling of the second tank T2.

[0059] Both ends 77A, 77B of the second circulation pipe 77 are connected to the second tank T2. Specifically, a first end 77A of the second circulation pipe 77 is connected to an outlet OL2 of the second tank T2, and a second end 77B of the second circulation pipe 77 is connected to an inlet IL2 of the second tank T2. The second circulation pipe 77 is a pipe for returning the phosphoric acid solution that has flowed in from the second tank T2 to the second tank T2.

[0060] The concentration pipe 85 is part of the second circulation pipe 77. A quartz heater 87 is provided in the concentration pipe 85. The quartz heater 87 has a configuration similar to that of the quartz heater 41 shown in FIG. 3(a). A second pump 89 is provided in the second circulation pipe 77 between the outlet OL2 and the quartz heater 87.

[0061] The second bypass pipe 78 bypasses the quartz heater 87. A first end 78A of the second bypass pipe 78 is connected to the second circulation pipe 77 between the second pump 89 and the quartz heater 87. A second end 78B of the second bypass pipe 78 is connected to the second circulation pipe 77 between the quartz heater 87 and a branch pipe 77C (described later). The second circulation pipe 77 between the first end 78A and the second end 78B is the concentration pipe 85. Therefore, both ends 78A, 78B of the second bypass pipe 78 are connected to the upstream end and downstream end of the concentration pipe 85. A non-quartz heater 91 is provided in the second bypass pipe 78. The non-quartz heater 91 has a configuration similar to that of the non-quartz heater 45 shown in FIG. 3(b).

[0062] The second circulation pipe 77 corresponds to the second circulation flow path of the present invention. The second bypass pipe 78 corresponds to the second bypass flow path of the present invention. The concentration pipe 85 corresponds to the second concentration flow path of the present invention. The quartz heater 87 corresponds to the second quartz heater of the present invention. The quartz tube 47 (see FIG. 3(a)) of the quartz heater 87 corresponds to the second quartz tube of the present invention. The non-quartz heater 91 corresponds to the second non-quartz heater of the present invention. The non-quartz tube 51 (see FIG. 3(b)) of the non-quartz heater 91 corresponds to the second non-quartz tube of the present invention.

[0063] Three branch pipes 77C, 77D, and 77E are provided on the second circulation pipe 77 between the quartz heater 87 and the inlet IL2. Three second supply pipes 80, 81, and 82 are pipes for sending the phosphoric acid solution from the second tank T2 to the three treatment units 2A, 2B, and 2C, respectively. A first end of the second supply pipe 80 is connected to the branch pipe 77C. A second end 80B of the second supply pipe 80 is disposed, for example, above the treatment tank 6 of the treatment unit 2A to supply the phosphoric acid solution to the treatment tank 6 of the treatment unit 2A.

[0064] Similarly, a first end of second supply pipe 81 is connected to branch pipe 77D. A second end 81B of second supply pipe 81 is disposed, for example, above treatment tank 6 of processing unit 2B to supply phosphoric acid solution to treatment tank 6 of processing unit 2B. A first end of second supply pipe 82 is connected to branch pipe 77E. A second end 82B of second supply pipe 82 is disposed, for example, above treatment tank 6 of processing unit 2C.

[0065] Each of the first supply pipe 37 and the second supply pipes 80 to 82 corresponds to a supply flow path of the present invention. The supply flow path of the present invention is a flow path for selectively sending the phosphoric acid solution in the first tank T1 to the treatment sections 2A, 2B, and 2C.

[0066] The main circulation section 33 is equipped with six on-off valves V9, V10, V11, V12, V13, and V14. The on-off valve V9 is provided in the concentration pipe 85 between the second pump 89 and the quartz heater 87. The on-off valve V10 is provided in the second bypass pipe 78 between the second pump 89 and the non-quartz heater 91. The on-off valve V11 is provided in the second circulation pipe 77 between the branch pipe 77E and the inlet IL2. The on-off valve V12 is provided in the second supply pipe 80. The on-off valve V13 is provided in the second supply pipe 81. The on-off valve V14 is provided in the second supply pipe 82.

[0067] The main circulation section 33 opens the on-off valves V9 and V11, closes the on-off valves V10, V12 to V14, and drives the second pump 89. This causes the phosphoric acid solution to circulate through the outlet OL2, the second pump 89, the quartz heater 87, and the inlet IL2, in that order. The main circulation section 33 also opens the on-off valves V10 and V11, closes the on-off valves V9, V12 to V14, and drives the second pump 89. This causes the phosphoric acid solution to circulate through the outlet OL2, the second pump 89, the non-quartz heater 91, and the inlet IL2, in that order.

[0068] In the main circulation section 33, for example, the on-off valves V10 and V12 are opened, the on-off valves V9, V11, V13, and V14 are closed, and the second pump 89 is driven. As a result, the phosphoric acid solution is sent in the following order: outlet OL2, second pump 89, non-quartz heater 91, second supply flow path 80, and treatment tank 6 of treatment section 2A. When the phosphoric acid solution is sent to treatment section 2B, the on-off valves V10 and V13 are opened, and the on-off valves V9, V11, V12, and V14 are closed. When the phosphoric acid solution is sent to treatment section 2C, the on-off valves V10 and V14 are opened, and the on-off valves V9, V11 to V13 are closed.

[0069] When supplying the phosphoric acid solution to each of the processing sections 2A, 2B, and 2C, the phosphoric acid solution may be passed through a concentration pipe 85 provided with a quartz heater 87. That is, the main circulation section 33 may, for example, open the on-off valves V9 and V12 and close the on-off valves V10, V11, V13, and V14, while driving the second pump 89.

[0070] The main circulation section 33 also includes a temperature sensor TS2, a phosphoric acid concentration sensor PS2, and a liquid level sensor LS2. The temperature sensor TS2 measures the temperature of the phosphoric acid solution in the second tank T2. The phosphoric acid concentration sensor PS2 has the same configuration as the phosphoric acid concentration sensor PS1 and measures the phosphoric acid concentration of the phosphoric acid solution in the second tank T2. The liquid level sensor LS2 detects the liquid level of the phosphoric acid solution in the second tank T2.

[0071] The substrate processing apparatus 1 includes a control unit 93 and a storage unit (not shown). The control unit 93 controls each component of the substrate processing apparatus 1. The control unit 93 includes one or more processors, such as a central processing unit (CPU). The storage unit includes at least one of a read-only memory (ROM), a random-access memory (RAM), and a hard disk. The storage unit stores a computer program for operating the substrate processing apparatus 1.

[0072] (2) Operation of the substrate processing apparatus 1 The operation of the substrate processing apparatus 1, mainly the operation of the auxiliary temperature adjustment unit 4, will be described with reference to FIG.

[0073] [Step S01] Supply of phosphoric acid solution (phosphoric acid) to the first tank T1 The on-off valve V1 opens. This allows the phosphoric acid solution to be supplied from the phosphoric acid supply source 55 to the first tank T1 through the pipe 56. The supply of the phosphoric acid solution is carried out based on the liquid level detected by the liquid level sensor LS1. The supplied phosphoric acid solution has a phosphoric acid concentration of 85% (room temperature). When a predetermined amount of phosphoric acid solution has been supplied to the first tank T1, the on-off valve V1 closes, and the supply of phosphoric acid solution to the first tank T1 stops.

[0074] [Step S02] Heating and concentration When the phosphoric acid solution is supplied from the phosphoric acid supply source 55, the preliminary circulation portion 31 increases the temperature of the phosphoric acid solution in the first tank T1 while concentrating the phosphoric acid solution.

[0075] The preliminary circulation section 31 concentrates the phosphoric acid solution in the first tank T1 when the concentration value measured by the phosphoric acid concentration sensor PS1 is lower than a preset threshold value (e.g., 88%). First, when concentrating the phosphoric acid solution in the first tank T1, the preliminary circulation section 31 opens the on-off valves V4 and V6 and closes the on-off valves V5 and V7, and also drives the first pump 43. This causes the phosphoric acid solution to circulate in the order of the outlet OL1, the first pump 43, the two quartz heaters 41 (concentration piping 39), the branch pipe 35C, and the inlet IL1.

[0076] Furthermore, the preliminary circulation section 31 heats the phosphoric acid solution passing through the concentration pipe 39 using two quartz heaters 41 while sending the phosphoric acid solution to the concentration pipe 39. The phosphoric acid solution passing through the two quartz heaters 41 may be heated to a first temperature (for example, 160°C) or higher, which will be described later.

[0077] The temperature sensor TS1 measures the temperature of the phosphoric acid solution in the first tank T1. The pre-circulation section 31 heats the phosphoric acid solution using two quartz heaters 41 so that the temperature measured by the temperature sensor TS1 becomes a preset first temperature (e.g., 160°C). The two quartz heaters 41 have high output and have a heating capacity twice that of a single quartz heater 87. This allows the temperature-raising and concentration process to be performed relatively quickly. Furthermore, when concentrating the phosphoric acid solution in the first tank T1, the on-off valve V8 is opened, causing the bubble supply unit 67 to supply bubbles into the phosphoric acid solution in the first tank T1. This promotes the concentration of the phosphoric acid solution.

[0078] The first temperature is preset to 160°C. However, the first temperature may be, for example, 150°C or higher. That is, the first temperature is a temperature lower than and close to the boiling point of the phosphoric acid solution, or higher than the boiling point of the phosphoric acid solution. The concentration is performed by heating the phosphoric acid solution. If the first temperature is lower than and close to the boiling point of the phosphoric acid solution, the concentration proceeds relatively quickly. If the first temperature is higher than the boiling point of the phosphoric acid solution, the concentration can be further promoted. The boiling point of a phosphoric acid solution with a phosphoric acid concentration of 85% at room temperature is 157°C to 158°C.

[0079] In step S02, the non-quartz heaters 45 that are not used to heat the phosphoric acid solution are either turned off or are heated in a state close to being turned off.

[0080] [Step S03] Maintaining temperature control After the phosphoric acid concentration of the phosphoric acid solution is concentrated from 85% to, for example, 88% to 89%, in order to maintain the phosphoric acid concentration, the preliminary circulation part 31 maintains the temperature of the phosphoric acid solution at 160° C. This will be explained in detail.

[0081] When the concentration value measured by the phosphoric acid concentration sensor PS1 is equal to or greater than the threshold value (88%), the preliminary circulation section 31 determines that the concentration of the phosphoric acid solution in the first tank T1 is complete, and maintains the temperature of the phosphoric acid solution in the first tank T1 (160°C). This makes it possible to switch between heating with the quartz heater 41 and heating with the non-quartz heater 45 based on the concentration value measured by the phosphoric acid concentration sensor PS1.

[0082] First, when the concentration of the phosphoric acid solution in the first tank T1 is completed, the preliminary circulation section 31 switches the circulation route. The preliminary circulation section 31 opens the on-off valves V5 and V6, closes the on-off valves V4 and V7, and drives the first pump 43. As a result, the phosphoric acid solution is circulated in the order of outlet OL1, first pump 43, non-quartz heater 45 (first bypass pipe 36), branch pipe 35C, and inlet IL1.

[0083] Furthermore, while the preliminary circulation section 31 sends the phosphoric acid solution to the first bypass pipe 36, it uses the non-quartz heater 45 to heat the phosphoric acid solution passing through the first bypass pipe 36. This maintains the temperature (160°C) of the phosphoric acid solution in the first tank T1. After the concentration is completed, the on-off valve V8 is closed, causing the bubble supply section 67 to stop supplying bubbles.

[0084] The phosphoric acid solution in the first tank T1, which is maintained at a controlled temperature, waits until an instruction to supply the solution to the second tank T2 is received. In this description, the concentration threshold of the phosphoric acid solution is set to 88%. In this regard, the threshold may be a value greater than the phosphoric acid concentration (85%) of the phosphoric acid solution supplied from the phosphoric acid supply source 55. Alternatively, an upper limit threshold may be set at which the phosphoric acid concentration is less than 100%. In this case, if the upper limit threshold is exceeded, pure water is supplied from the pure water supply source 59 to the first tank T1. In this case, the process returns to step S02.

[0085] In step S03, the quartz heaters 41 that are not used to heat the phosphoric acid solution are either stopped or are operating in a state close to being stopped.

[0086] [Step S04] Supply of phosphoric acid solution to second tank T2 The preliminary circulation section 31 supplies the phosphoric acid solution from the first tank T1 to the second tank T2. The preliminary circulation section 31 opens the on-off valves V5 and V7, closes the on-off valves V4 and V6, and drives the first pump 43. As a result, the phosphoric acid solution flows in the following order: outlet OL1, first pump 43, non-quartz heater 45, branch pipe 35C, first supply pipe 37, and second tank T2.

[0087] When the phosphoric acid solution is sent from the first tank T1 to the second tank T2, the liquid level sensor LS1 detects that the liquid level of the phosphoric acid solution in the first tank T1 has dropped. Therefore, it is necessary to supply the phosphoric acid solution from the phosphoric acid supply source 55 to the first tank T1. In this case, the process proceeds to the next step S05 and returns to step S01.

[0088] [Step S05] Heating and concentration When the phosphoric acid solution is supplied to the second tank T2, the main circulation section 33 performs the same operations as the above-described steps S02 and S03 to stabilize the phosphoric acid concentration and the temperature of the phosphoric acid solution. Therefore, the main circulation section 33 concentrates the phosphoric acid solution while increasing the temperature of the phosphoric acid solution in the second tank T2. This will be explained in detail.

[0089] When the concentration value measured by the phosphoric acid concentration sensor PS2 is lower than a preset threshold value (e.g., 88%), the main circulation part 33 concentrates the phosphoric acid solution in the second tank T2. First, when concentrating the phosphoric acid solution in the second tank T2, the main circulation part 33 opens the on-off valves V9 and V11 and closes the on-off valves V10, V12 to V14, and drives the second pump 89. As a result, the phosphoric acid solution is circulated in the order of outlet OL2, second pump 89, quartz heater 87 (concentration pipe 85), and inlet IL2.

[0090] Furthermore, the main circulation section 33 uses a quartz heater 87 to heat the phosphoric acid solution passing through the concentration pipe 85. A temperature sensor TS2 measures the temperature of the phosphoric acid solution in the second tank T2. The main circulation section 33 uses the quartz heater 87 to heat the phosphoric acid solution so that the temperature measured by the temperature sensor TS2 becomes a preset first temperature (e.g., 160°C).

[0091] In step S05, the non-quartz heaters 91 that are not used to heat the phosphoric acid solution are either stopped or are operating in a state close to being stopped.

[0092] [Step S06] Maintaining temperature control After the phosphoric acid concentration of the phosphoric acid solution is concentrated to, for example, 88% to 89%, the main circulation part 33 maintains the temperature of the phosphoric acid solution at 160° C. in order to maintain the phosphoric acid concentration.

[0093] When the concentration value measured by the phosphoric acid concentration sensor PS2 is equal to or higher than the threshold value (88%), the main circulation section 33 determines that the concentration of the phosphoric acid solution in the second tank T2 is complete and maintains the temperature of the phosphoric acid solution in the second tank T2 (160°C).

[0094] That is, when the concentration of the phosphoric acid solution in the second tank T2 is completed, the main circulation section 33 first switches the circulation route. The main circulation section 33 opens the on-off valves V10 and V11 and closes the on-off valves V9, V12 to V14, and also drives the second pump 89. As a result, the phosphoric acid solution is circulated in the order of the outlet OL2, the second pump 89, the non-quartz heater 91 (the second bypass pipe 78), and the inlet IL2.

[0095] Furthermore, the main circulation section 33 heats the phosphoric acid solution passing through the second bypass pipe 78 using the non-quartz heater 91 while sending the phosphoric acid solution to the second bypass pipe 78. This maintains the temperature (160°C) of the phosphoric acid solution in the second tank T2.

[0096] The phosphoric acid solution in the second tank T2, which is maintained at a controlled temperature, waits until an instruction to supply the solution to each processing unit 2A, 2B, and 2C is received. In the explanation of step S06, the concentration threshold of the phosphoric acid solution is set to 88%. In this regard, the threshold may be a value greater than the phosphoric acid concentration (85%) of the phosphoric acid solution supplied from the phosphoric acid supply source 55. Alternatively, an upper limit threshold may be set such that the phosphoric acid concentration is less than 100%. In this case, if the upper limit threshold is exceeded, pure water is supplied from the pure water supply source 59 to the second tank T2. In this case, the process returns to step S05.

[0097] In step S06, the quartz heaters 87 that are not used to heat the phosphoric acid solution are either stopped or are heated in a state close to being stopped.

[0098] [Step S07] Supply of phosphoric acid solution to treatment section 2A (2B, 2C) The main circulation section 33 supplies the phosphoric acid solution from the second tank T2 to each of the processing sections 2A, 2B, and 2C. The main circulation section 33 opens the on-off valves V10 and V12, closes the on-off valves V9, V11, V13, and V14, and drives the second pump 89. This causes the phosphoric acid solution to be sent in the following order: outlet OL2, second pump 89, non-quartz heater 91, second supply pipe 80, and processing tank 6 of processing section 2A. A phosphoric acid solution with a low silicon concentration is supplied to the processing tank 6 of processing section 2A.

[0099] When the phosphoric acid solution is sent to the processing section 2B, the on-off valves V10 and V13 are opened and the on-off valves V11, V12, and V14 are closed. When the phosphoric acid solution is sent to the processing section 2C, the on-off valves V10 and V14 are opened and the on-off valves V11, V12 to V14 are closed.

[0100] Here, two supply methods will be explained. The two supply methods are constant replenishment and partial solution replacement. See FIG. 2. First, constant replenishment will be explained. In this explanation, the phosphoric acid solution is supplied to processing section 2A. The same procedure is followed when supplying phosphoric acid solution to either processing section 2B or 2C.

[0101] The term "constant replenishment" means that, when substrate processing is being performed by immersing a plurality of substrates W held by the lifter 11 in the processing tank 6 of the processing section 2A, the phosphoric acid solution is continuously supplied to the processing tank 6 of the processing section 2A by the auxiliary temperature control unit 4. This allows the phosphoric acid solution in the processing tank 6 to be gradually replaced, thereby preventing an increase in the silicon concentration of the phosphoric acid solution in the processing tank 6.

[0102] Each substrate W immersed in the processing bath 6 has a structure in which silicon nitride films and silicon oxide films are alternately stacked. The substrate processing involves selectively etching the silicon nitride film using a phosphoric acid solution. Excess phosphoric acid solution in the processing section 2A is naturally discharged from a discharge pipe 14 connected to the outer bath 7. When the substrate processing is completed, the supply of phosphoric acid solution from the preliminary temperature control unit 4 is stopped.

[0103] Next, partial liquid exchange will be described. Partial liquid exchange refers to the supply of phosphoric acid solution to the processing tank 6 of processing unit 2A through second supply piping 80 by auxiliary temperature adjustment unit 4 while discharging a portion of the phosphoric acid solution from the processing tank 6 during substrate processing in which the substrate W is immersed in the processing tank 6 of processing unit 2A.

[0104] A silicon concentration sensor 23 (see FIG. 2) is provided in the treatment section circulation flow path 9 of treatment section 2A. When the silicon concentration value measured by silicon concentration sensor 23 is greater than a preset threshold, the substrate treatment apparatus 1 opens on-off valve V22 and causes preliminary temperature adjustment unit 4 to supply phosphoric acid solution from second tank T2 to treatment tank 6 of treatment section 2A. By opening on-off valve V22, the phosphoric acid solution in treatment tank 6 of treatment section 2A is discharged through discharge pipe 30. Simultaneously with this discharge, the phosphoric acid solution is supplied to treatment tank 6 of treatment section 2A by preliminary temperature adjustment unit 4. This partially replaces the phosphoric acid solution in treatment tank 6, allowing the silicon concentration value of the phosphoric acid solution to be reduced relatively significantly.

[0105] It should be noted that partial solution replacement may be performed during the continuous replenishment operation. The method of supplying the phosphoric acid solution to each of the treatment sections 2A, 2B, and 2C is arbitrary and is not limited to the two supply methods described above.

[0106] When the phosphoric acid solution is sent from the second tank T2 to each of the processing sections 2A, 2B, and 2C, the liquid level sensor LS2 detects that the liquid level of the phosphoric acid solution in the second tank T2 has dropped. Therefore, it is necessary to supply the phosphoric acid solution from the first tank T1 to the second tank T2. In this case, the process returns to step S04.

[0107] According to this embodiment, a quartz heater 41 is provided in the first concentration pipe 39, which is part of the first circulation pipe 35, and a non-quartz heater 45 is provided in the first bypass pipe 36, which bypasses the quartz heater 41. When concentrating the phosphoric acid solution in the first tank T1, the quartz heater 41 is used to heat the phosphoric acid solution passing through the concentration pipe 39. Furthermore, when the concentration of the phosphoric acid solution in the first tank T1 is completed and the temperature of the phosphoric acid solution in the first tank T1 is to be maintained, the non-quartz heater 41 is used to heat the phosphoric acid solution passing through the first bypass pipe 36. The use of the non-quartz heater 45 prevents silicon from eluting into the phosphoric acid solution, resulting in a reduction in the overall amount of silicon eluting into the phosphoric acid solution. Therefore, for example, it is possible to prevent the silicon concentration of the phosphoric acid solution supplied to the processing unit 2A from becoming too high.

[0108] A quartz heater 87 is provided in the second concentration pipe 85, which is part of the second circulation pipe 77, and a non-quartz heater 91 is provided in the second bypass pipe 78, which bypasses the quartz heater 87. When concentrating the phosphoric acid solution in the second tank T2, the phosphoric acid solution passing through the concentration pipe 85 is heated using the quartz heater 87. When the concentration of the phosphoric acid solution in the second tank T2 is completed and the temperature of the phosphoric acid solution in the second tank T2 is to be maintained, the phosphoric acid solution passing through the second bypass pipe 78 is heated using the second non-quartz heater 91. When the second non-quartz heater 91 is used, silicon is prevented from eluting into the phosphoric acid solution, and the amount of silicon eluting into the phosphoric acid solution is reduced overall. This prevents the silicon concentration of the phosphoric acid solution supplied to, for example, the processing unit 2A from becoming too high. Example 2

[0109] Next, a second embodiment of the present invention will be described with reference to the drawings. Note that the description overlapping with the first embodiment will be omitted.

[0110] In Example 1, the temperature of the phosphoric acid solution is maintained at 160°C in the two steps S03 and S06. In contrast, in Example 2, the temperature of the phosphoric acid solution is maintained at 120°C.

[0111] The auxiliary temperature adjustment unit 4 of the second embodiment has the same structural features as the auxiliary temperature adjustment unit 4 of the first embodiment shown in Fig. 1. That is, in the auxiliary temperature adjustment unit 4 of the second embodiment, the auxiliary circulation section 31 includes a first bypass pipe 36 and a non-quartz heater 45. Also, the main circulation section 33 includes a second bypass pipe 78 and a non-quartz heater 91.

[0112] Next, the operation of the preliminary temperature adjustment unit 4 will be described with reference to Fig. 5. Note that steps S11, S12, S14, S15, and S17 shown in Fig. 5 are the same as steps S01, S02, S04, S05, and S07 shown in Fig. 4, respectively. In step S12, in order to concentrate the phosphoric acid solution, the preliminary circulation section 31 heats the phosphoric acid solution passing through the concentration pipe 39 using the two quartz heaters 41 so that the temperature of the phosphoric acid solution in the first tank T1 becomes a preset first temperature (160°C).

[0113] [Step S13] Maintain temperature control state After the phosphoric acid concentration of the phosphoric acid solution is concentrated from 85% to, for example, 88% to 89%, the preliminary circulation section 31 maintains the temperature of the phosphoric acid solution at 120° C. A more detailed description will be given below.

[0114] When the concentration value measured by the phosphoric acid concentration sensor PS1 is equal to or higher than the threshold value (88%), the preliminary circulation section 31 determines that the concentration of the phosphoric acid solution in the first tank T1 is complete and maintains the temperature of the phosphoric acid solution in the first tank T1 (120°C).

[0115] That is, when the concentration of the phosphoric acid solution in the first tank T1 is completed, the preliminary circulation section 31 first switches the circulation route. The preliminary circulation section 31 opens the on-off valves V5 and V6, closes the on-off valves V4 and V7, and drives the first pump 43. As a result, the phosphoric acid solution is circulated in the following order: outlet OL1, first pump 43, non-quartz heater 45 (first bypass piping 36), branch pipe 35C, and inlet IL1. Furthermore, while sending the phosphoric acid solution to the first bypass piping 36, the preliminary circulation section 31 uses the non-quartz heater 45 to heat the phosphoric acid solution passing through the first bypass piping 36.

[0116] At this time, the pre-circulation section 31 is heated using a non-quartz heater 45 so that the temperature of the phosphoric acid solution in the first tank T1 becomes a second temperature (120°C). The second temperature (120°C) is set lower than the first temperature (160°C). In this description, the second temperature is set to 120°C. In this regard, the second temperature may be set, for example, to a temperature equal to or higher than 100°C and lower than the boiling point of the phosphoric acid solution. If the temperature of the phosphoric acid solution becomes lower than 100°C, the phosphoric acid solution will absorb moisture. As a result, the phosphoric acid concentration of the phosphoric acid solution will decrease. By setting the temperature of the phosphoric acid solution to 100°C or higher, it is possible to prevent the phosphoric acid solution from absorbing moisture.

[0117] The phosphoric acid solution is sent from the first tank T1 to the second tank T2 (step S14). In order to concentrate the phosphoric acid solution, the main circulation part 33 heats the phosphoric acid solution passing through the concentration pipe 85 using the quartz heater 87 so that the temperature of the phosphoric acid solution in the second tank T2 becomes a preset first temperature (160°C) (step S15).

[0118] [Step S16] Maintain temperature control state After the phosphoric acid concentration of the phosphoric acid solution is concentrated to, for example, 88% to 89%, the main circulation part 33 maintains the temperature of the phosphoric acid solution at 120° C. A more detailed description will be given below.

[0119] When the concentration value measured by the phosphoric acid concentration sensor PS2 is equal to or higher than the threshold value (88%), the main circulation section 33 determines that the concentration of the phosphoric acid solution in the second tank T2 is complete and maintains the temperature of the phosphoric acid solution in the second tank T2 (120°C).

[0120] That is, when the concentration of the phosphoric acid solution in the second tank T2 is completed, the main circulation section 33 first switches the circulation route. The main circulation section 33 opens the on-off valves V10 and V11 and closes the on-off valves V9, V12 to V14, and also drives the second pump 89. As a result, the phosphoric acid solution is circulated in the order of outlet OL2, second pump 89, non-quartz heater 91 (second bypass piping 78), and inlet IL2. Furthermore, while sending the phosphoric acid solution to the second bypass piping 78, the main circulation section 33 uses the non-quartz heater 91 to heat the phosphoric acid solution passing through the second bypass piping 78.

[0121] At this time, the main circulation portion 33 is heated using the non-quartz heater 91 so that the temperature of the phosphoric acid solution in the second tank T2 becomes a second temperature (120° C.) lower than the first temperature (160° C.).

[0122] Thereafter, in step S17, a phosphoric acid solution at 120°C is supplied to the treatment tank 6 by the preliminary temperature control unit 4. There is concern that supplying a phosphoric acid solution at 120°C into a phosphoric acid solution at 160°C in the treatment tank 6 may cause problems in the treatment process. However, the phosphoric acid concentration of the phosphoric acid solution from the preliminary temperature control unit 4 is the same as that of the phosphoric acid solution in the treatment tank 6. Therefore, unstable behavior such as boiling does not occur. Furthermore, if the temperature-raising capacity of the two heaters 8, 19 in the treatment tank 6 is sufficient, heating to 160°C can be performed quickly, and it is thought that there will be no problems in the treatment process.

[0123] In addition to the effects of the first embodiment, this embodiment has the following effects. That is, the output of the non-quartz heater 45 can be reduced. Therefore, damage to the non-quartz tube can be prevented. For example, there is a possibility that the non-quartz tube may melt due to heating. This can be prevented. Furthermore, the options for non-quartz heaters can be increased. Example 3

[0124] Next, a third embodiment of the present invention will be described with reference to the drawings. Note that the description overlapping with the first and second embodiments will be omitted.

[0125] 6 is a diagram showing the configuration of the substrate processing apparatus 1 according to Example 3. In Example 3, the main circulation section 33 does not include the second bypass pipe 78, the non-quartz heater 91, and the two on-off valves V9 and V10 shown in FIG. 1. In addition, the concentration pipe 85 is not distinguished in the second circulation pipe 77. The other configurations are the same as those shown in FIG.

[0126] Next, the operation of the auxiliary temperature adjustment unit 4 will be described with reference to Fig. 7. The operations in steps S21 to S24 shown in Fig. 7 are the same as the operations in steps S01 to S04 shown in Fig. 4, respectively.

[0127] In step S24, the phosphoric acid solution is supplied from the first tank T1 to the second tank T2. The phosphoric acid solution in the first tank T1 is maintained at 160° C. and is concentrated to 88% to 89%. The process proceeds to step S26.

[0128] [Step S26] Maintain temperature control state First, the main circulation part 33 circulates the phosphoric acid solution in the second tank T2. Specifically, the main circulation part 33 opens the on-off valve V11, closes the on-off valves V12 to V14, and drives the second pump 89. As a result, the phosphoric acid solution is circulated in the order of the outlet OL2, the second pump 89, the quartz heater 87, the on-off valve V11, and the inlet IL2.

[0129] The main circulation section 33 does not heat the phosphoric acid solution to the first temperature (160°C). That is, the main circulation section 33 uses the quartz heater 87 to heat the phosphoric acid solution passing through the second circulation pipe 77 so that the temperature of the phosphoric acid solution in the second tank T2 becomes the second temperature (120°C). This maintains the temperature of the phosphoric acid solution in the second tank T2 at 120°C. The temperature of the phosphoric acid solution in the second tank T2 is measured by the temperature sensor TS2.

[0130] The second temperature is set to a temperature lower than the first temperature. In this description, the second temperature is set to 120°C. In this regard, the second temperature may be set, for example, in the range of 100°C to 140°C. If the temperature of the phosphoric acid solution falls below 100°C, the phosphoric acid solution will absorb moisture. Furthermore, when the phosphoric acid solution is heated to 140°C using the quartz heater 87 (41), the amount of silicon (Si) eluted can be reduced to approximately half of that when the phosphoric acid solution is heated to 160°C using the quartz heater 87 (41).

[0131] Moreover, it is preferable that the second temperature be set in the range of 100° C. to 120° C. This is because it is believed that when the quartz heater 87 (41) is used to heat the phosphoric acid solution to 120° C., the amount of silicon (Si) eluted can be reduced to about 1 / 10 compared to when the quartz heater 87 (41) is used to heat the phosphoric acid solution to 160° C.

[0132] FIG. 8 is a graph showing the relationship between the temperature control time of the auxiliary temperature control unit 4 and the expected silicon concentration. In FIG. 8, the temperature control time increases as time progresses to the right. The expected silicon concentration increases as the temperature progresses. The expected silicon concentration is calculated when the phosphoric acid solution is heated to 160°C and 120°C using three quartz heaters 41A, 41B, and 87. FIG. 8 shows that the expected silicon concentration at 120°C is approximately 1 / 10 of the expected silicon concentration at 160°C. Furthermore, the expected silicon concentration at 140°C is predicted to be between the concentrations at 160°C and 120°C, i.e., approximately 1 / 2 of the concentration at 160°C.

[0133] According to this embodiment, after the concentration of the phosphoric acid solution is completed, the temperature of the phosphoric acid solution is maintained at a second temperature lower than the first temperature set during the concentration of the phosphoric acid solution. By lowering the heating temperature by the second quartz heater 87, it is possible to suppress the elution of silicon from the second quartz tube 47 (see FIG. 3(a)) of the second quartz heater 87. As a result, the elution of silicon into the phosphoric acid solution is reduced overall. This makes it possible to prevent the silicon concentration of the phosphoric acid solution supplied to, for example, the processing unit 2A from becoming too high.

[0134] 7, the phosphoric acid solution in the first tank T1 is maintained at the first temperature (160°C). In this regard, as in step S13 of FIG. 5, the phosphoric acid solution in the first tank T1 may be heated using the non-quartz heater 45 to a second temperature (120°C) lower than the first temperature.

[0135] The main circulation section 33 is provided with the quartz heater 87. Instead of the quartz heater 87, a non-quartz heater 45 (91) as shown in Fig. 3(b) may be provided in the first circulation pipe 35. The main circulation section 33 may use the quartz heater 87 to heat the phosphoric acid solution in the second tank T2 to 160°C when concentrating the phosphoric acid solution, and to heat the phosphoric acid solution in the second tank T2 to 120°C when maintaining the temperature-controlled state. Example 4

[0136] Next, a fourth embodiment of the present invention will be described with reference to the drawings. Note that descriptions that overlap with those of the first to third embodiments will be omitted. Fig. 9 is a diagram showing the configuration of a preliminary temperature adjustment unit 4 according to the fourth embodiment.

[0137] In the first embodiment, the preliminary circulation section 31 is provided with the non-quartz heater 45, and the main circulation section 33 is provided with the non-quartz heater 91. In this regard, the preliminary temperature adjustment unit 4 of the fourth embodiment is not provided with the two non-quartz heaters 45, 91.

[0138] 9, in the preliminary circulation section 31, both ends 35A, 35B of the first circulation pipe 35 are connected to the outlet OL1 and the inlet IL1, respectively, of the first tank T1. The first circulation pipe 35 is provided with, in order from the outlet OL1 side, a first pump 43, a quartz heater 41A, a quartz heater 41B, a branch pipe 35C, and an on-off valve V6.

[0139] In the main circulation section 33, both ends 77A, 77B of the second circulation pipe 77 are connected to the outlet OL2 and the inlet IL2, respectively, of the second tank T2. The second circulation pipe 77 is provided with, in order from the outlet OL2, a second pump 89, a quartz heater 87, branch pipes 77C, 77D, 77E, and an on-off valve V11.

[0140] Next, the operation of the preliminary temperature adjustment unit 4 will be described with reference to Fig. 10. A phosphoric acid solution is supplied from the phosphoric acid supply source 55 to the first tank T1 (step S31).

[0141] [Step S32] Heating and concentration The preliminary circulation section 31 concentrates the phosphoric acid solution in the first tank T1 when the concentration value measured by the phosphoric acid concentration sensor PS1 is lower than a preset threshold value (e.g., 88%). When concentrating the phosphoric acid solution, the preliminary circulation section 31 first opens the on-off valve V6, closes the on-off valve V7, and drives the first pump 43. This causes the phosphoric acid solution to circulate through the first circulation pipe 35 in the order of outlet OL1, first pump 43, two quartz heaters 41, on-off valve V6, and inlet IL1.

[0142] Furthermore, the preliminary circulation section 31 heats the phosphoric acid solution passing through the first circulation pipe 35 using two quartz heaters 41. The preliminary circulation section 31 also heats the phosphoric acid solution so that the temperature measured by the temperature sensor TS1 becomes a preset first temperature (for example, 160°C).

[0143] [Step S33] Maintain temperature control state The circulation of the phosphoric acid solution continues. When the concentration value measured by the phosphoric acid concentration sensor PS1 is equal to or greater than the threshold value (88%), the preliminary circulation section 31 determines that the concentration of the phosphoric acid solution in the first tank T1 is complete, and maintains the temperature of the phosphoric acid solution in the first tank T1 (120°C). That is, when the concentration of the phosphoric acid solution in the first tank T1 is complete, the preliminary circulation section 31 heats the phosphoric acid solution passing through the first circulation piping 35 using at least one of the two quartz heaters 41 while sending the phosphoric acid solution to the first circulation piping 35.

[0144] At this time, the preliminary circulation section 31 heats the phosphoric acid solution passing through the first circulation pipe 35 so that the temperature of the phosphoric acid solution in the first tank T1 becomes a second temperature (120°C). The second temperature is set lower than the first temperature.

[0145] [Step S34] Supplying phosphoric acid solution to second tank T2 The preliminary circulation section 31 supplies the phosphoric acid solution from the first tank T1 to the second tank T2. The preliminary circulation section 31 opens the on-off valve V7, closes the on-off valve V6, and drives the first pump 43.

[0146] [Step S35] Heating and concentration First, the main circulation section 33 opens the on-off valve V11, closes the on-off valves V12, V13, and V14, and drives the second pump 89. As a result, the phosphoric acid solution is circulated through the second circulation pipe 77 in the order of the outlet OL2, the second pump 89, the quartz heater 87, the on-off valve V11, and the inlet IL2.

[0147] In this state, the main circulation part 33 concentrates the phosphoric acid solution in the second tank T2 when the concentration value measured by the phosphoric acid concentration sensor PS2 is lower than a preset threshold value (e.g., 88%). At this time, the main circulation part 33 heats the phosphoric acid solution passing through the second circulation pipe 77 using the quartz heater 87. The main circulation part 33 also heats the phosphoric acid solution so that the temperature measured by the temperature sensor TS2 becomes a preset first temperature (e.g., 160°C).

[0148] [Step S36] Maintain temperature control state After the phosphoric acid concentration of the phosphoric acid solution is concentrated to, for example, 88% to 89%, the main circulation portion 33 maintains the temperature of the phosphoric acid solution (120° C.).

[0149] The circulation of the phosphoric acid solution continues. When the concentration value measured by the phosphoric acid concentration sensor PS2 is equal to or greater than the threshold value (88%), the main circulation section 33 determines that the concentration of the phosphoric acid solution in the second tank T2 is complete, and maintains the temperature of the phosphoric acid solution in the second tank T2 at a preset temperature (120°C). That is, when the concentration of the phosphoric acid solution in the second tank T2 is complete, the main circulation section 33 heats the phosphoric acid solution passing through the second circulation pipe 77 using the quartz heater 87 while sending the phosphoric acid solution to the second circulation pipe 77.

[0150] At this time, the main circulation portion 33 is heated using the quartz heater 87 so that the temperature of the phosphoric acid solution in the second tank T2 becomes a second temperature (120° C.) lower than the first temperature (160° C.).

[0151] [Step S37] Supply of phosphoric acid solution to treatment section 2A (2B, 2C) The main circulation part 33 supplies the phosphoric acid solution in the second tank T2 to, for example, the treatment part 2A. Specifically, the main circulation part 33 opens the on-off valve V12 and closes the on-off valves V11, V13, and V14, and also drives the second pump 89. As a result, the phosphoric acid solution is supplied to the treatment tank 6 of the treatment part 2A through the second supply pipe 80.

[0152] According to this embodiment, when concentrating the phosphoric acid solution in the first tank T1, the phosphoric acid solution passing through the first circulation flow path 35 is heated using two quartz heaters 41 so that the temperature of the phosphoric acid solution in the first tank T1 becomes a first temperature. When the concentration of the phosphoric acid solution in the first tank T1 is completed and the temperature of the phosphoric acid solution in the first tank T1 is maintained, the quartz heater 41 is used to heat the phosphoric acid solution passing through the first circulation flow path 35 so that the temperature of the phosphoric acid solution in the first tank T1 becomes a second temperature lower than the first temperature. By using the quartz heater 41 to raise the temperature to the second temperature lower than the first temperature, less silicon is eluted into the phosphoric acid solution at the second temperature than the first temperature. Therefore, for example, it is possible to prevent the silicon concentration of the phosphoric acid solution supplied to the processing unit 2A from becoming high.

[0153] 1. In the auxiliary temperature adjustment unit 4 shown in FIG. 9, the main circulation portion 33 shown in FIG. 9 may be replaced with the main circulation portion 33 shown in FIG. Example 5

[0154] Next, a fifth embodiment of the present invention will be described with reference to the drawings. Note that the description overlapping with the first to fourth embodiments will be omitted.

[0155] In the first embodiment, the preliminary temperature adjustment unit 4 includes two circulation parts 31 and 33, and prepares the phosphoric acid solution to be supplied to each of the treatment parts 2A, 2B, and 2C in two stages. However, the preliminary temperature adjustment unit 4 may prepare the phosphoric acid solution in one stage.

[0156] Refer to Fig. 11. The preliminary temperature adjustment unit 4 has a configuration similar to the preliminary circulation section 31 shown in Fig. 1. That is, the preliminary temperature adjustment unit 4 includes a first tank T1, a first circulation pipe 35, a first bypass pipe 36, and three supply pipes (supply flow paths) 101, 102, and 103. Three branch pipes 35D, 35E, and 35F are provided in the first circulation pipe 35 between the second end 36B of the first bypass pipe 36 and the inlet IL1.

[0157] The three branch pipes 35D, 35E, and 35F are respectively connected to supply pipes 101, 102, and 103. The supply pipe 101 is a pipe for directly supplying the phosphoric acid solution to the treatment tank 6 of the treatment unit 2A. The two supply pipes 102 and 103 are pipes for directly supplying the phosphoric acid solution to the two treatment tanks 6 of the treatment units 2B and 2C, respectively.

[0158] The standby temperature adjustment unit 4 of this fifth embodiment includes six on-off valves V4, V5, V6, V16, V17, and V18. The on-off valve V6 is provided in the first circulation pipe 35 between the branch pipe 35F and the inlet IL1. The on-off valve V16 is provided in the supply pipe 101. The on-off valve V17 is provided in the supply pipe 102. The on-off valve V18 is provided in the supply pipe 103.

[0159] Next, the operation of the preliminary temperature adjustment unit 4 of this embodiment will be described with reference to Fig. 12. A phosphoric acid solution with a concentration of 85% is supplied from the phosphoric acid supply source 55 to the first tank T1 at room temperature (step S41).

[0160] [Step S42] Heating and concentration The preliminary temperature adjustment unit 4 concentrates the phosphoric acid solution while increasing the temperature of the phosphoric acid solution in the first tank T1.

[0161] When the concentration value measured by the phosphoric acid concentration sensor PS1 is lower than a preset threshold value (e.g., 88%), the preliminary temperature adjustment unit 4 concentrates the phosphoric acid solution in the first tank T1. When concentrating the phosphoric acid solution, the preliminary temperature adjustment unit 4 first opens the on-off valves V4 and V6 and closes the on-off valves V5, V16 to V18, and also drives the first pump 43. This causes the phosphoric acid solution to circulate in the order of outlet OL1, first pump 43, two quartz heaters 41 (concentration pipe 39), on-off valve V6, and inlet IL1.

[0162] Furthermore, while the preliminary temperature adjustment unit 4 sends the phosphoric acid solution through the concentration pipe 39, it uses two quartz heaters 41 to heat the phosphoric acid solution passing through the concentration pipe 39. The heating by the two quartz heaters 41 is performed so that the temperature measured by the temperature sensor TS1 becomes a preset first temperature (160°C). The temperature sensor TS1 measures the temperature of the phosphoric acid solution in the first tank T1. The concentration operation is completed when the concentration value measured by the phosphoric acid concentration sensor PS1 reaches a preset threshold value (for example, 88%).

[0163] [Step S43] Maintain temperature control state After the concentration is completed, the preliminary temperature adjustment unit 4 maintains the temperature of the phosphoric acid solution at 160° C. in order to maintain the phosphoric acid concentration.

[0164] When the concentration value measured by the phosphoric acid concentration sensor PS1 is equal to or greater than the threshold value (88%), the preliminary temperature adjustment unit 4 determines that the concentration of the phosphoric acid solution in the first tank T1 is complete and maintains the temperature of the phosphoric acid solution in the first tank T1 (160°C). That is, when the concentration of the phosphoric acid solution in the first tank T1 is complete, the preliminary temperature adjustment unit 4 switches the circulation route. The preliminary temperature adjustment unit 4 opens the on-off valves V5 and V6, sets the on-off valves V5, V16 to V18, and drives the first pump 43. As a result, the phosphoric acid solution is circulated in the order of outlet OL1, first pump 43, non-quartz heater 45 (first bypass pipe 36), on-off valve V6, and inlet IL1.

[0165] The preliminary temperature adjustment unit 4 uses the non-quartz heater 45 to heat the phosphoric acid solution passing through the first bypass pipe 36 while sending the phosphoric acid solution to the first bypass pipe 36. This maintains the temperature (160°C) of the phosphoric acid solution in the first tank T1. The phosphoric acid solution in the first tank T1, whose temperature is being maintained, waits until an instruction to supply the solution to one of the three processing units 2A, 2B, 2C is received.

[0166] [Step S44] Supply of phosphoric acid solution to treatment section 2A (2B, 2C) For example, the preliminary temperature adjustment unit 4 sends the phosphoric acid solution in the first tank T1 to the processing unit 2A. The preliminary temperature adjustment unit 4 opens the on-off valves V5 and V16 and closes the on-off valves V4, V6, V17, and V18, and also drives the first pump 43. As a result, the phosphoric acid solution in the first tank T1 is supplied in the following order: outlet OL1, first pump 43, non-quartz heater 45, branch pipe 35D, supply pipe 101, and processing tank 6 of processing unit 2A.

[0167] When the phosphoric acid solution is supplied from the first tank T1 to one of the three treatment sections 2A, 2B, and 2C, the liquid level sensor LS1 detects that the water level of the phosphoric acid solution in the first tank T1 has dropped. In this case, it is necessary to replenish the first tank T1 with phosphoric acid solution from the phosphoric acid supply source 55. Therefore, the process returns to step S41.

[0168] According to this embodiment, the amount of silicon eluted into the phosphoric acid solution is reduced overall, as in Example 1. Therefore, it is possible to prevent the silicon concentration in the phosphoric acid solution supplied to, for example, treatment section 2A from becoming high.

[0169] The present invention is not limited to the above-described embodiment, but can be modified as follows.

[0170] (1) In the above-described Example 5, the phosphoric acid solution was heated by the quartz heater 41 during the concentration operation, and heated by the non-quartz heater 45 when the temperature was being controlled. In this regard, as described in Example 4, the non-quartz heater 45 may be omitted, and the phosphoric acid solution may be heated to the first temperature (160°C) by the quartz heater 41 during the concentration operation, and heated to the second temperature (120°C) by the quartz heater 41 when the temperature was being controlled.

[0171] 9 includes two circulation parts 31 and 33, and prepares the phosphoric acid solution to be supplied to each of the treatment parts 2A, 2B, and 2C in two stages. In this regard, the preliminary temperature adjustment unit 4 may be configured to prepare the phosphoric acid solution in one stage.

[0172] (2) In the above-described embodiments and modified example (1), when supplying phosphoric acid solution to treatment section 2A, preliminary temperature adjustment unit 4 directly supplies the phosphoric acid solution to treatment tank 6. In this regard, preliminary temperature adjustment unit 4 may directly supply the phosphoric acid solution to outer tank 7, and then indirectly supply the phosphoric acid solution to treatment tank 6 via outer tank 7 and treatment section circulation flow path 9.

[0173] (3) In each of the above-described Examples 2 to 4 and each of the modified examples, the phosphoric acid solution was heated to a first temperature (160°C) during the concentration operation, and to a second temperature (120°C) when the temperature control state was maintained. Then, the phosphoric acid solution maintained at the second temperature (120°C) was supplied to the treatment tank 6, which stores the phosphoric acid solution heated to 160°C. In this regard, for example, in FIG. 9, heaters 105, 106, and 107 indicated by two-dot chain lines may be provided on each of the three supply pipes 80 to 82. For example, the heater 105 heats the phosphoric acid solution passing through the second supply pipe 80. The two heaters 106 and 107 heat the two supply pipes 81 and 82, respectively.

[0174] For example, when the temperature of the phosphoric acid solution supplied to processing unit 2A through second supply pipe 80 is lower than the temperature of the phosphoric acid solution in processing tank 6 of processing unit 2A, the temperature difference can be suppressed. Each of heaters 105 to 107 corresponds to the supply flow path heater of the present invention. Each of heaters 105 to 107 is preferably made of a non-quartz heater.

[0175] (4) In each of the above-described Examples 2 to 4 and each of the modified examples, the first temperature of the phosphoric acid solution during concentration is set to 160°C in both the preliminary circulation section 31 and the main circulation section 33, and the second temperature of the phosphoric acid solution during temperature control is set to 160°C or 120°C. In this regard, the first temperature set in the preliminary circulation section 31 may be different from the first temperature set in the main circulation section 33. Similarly, the second temperature set in the preliminary circulation section 31 may be different from the second temperature set in the main circulation section 33.

[0176] (5) In each of the above-described Examples 1 to 4 and each of the modified examples, the bubble supply unit 67 is provided only in the first tank T1. However, the bubble supply unit 67 may be provided in the second tank T2.

[0177] (6) In each of the above-described embodiments and modifications, the first end of the first supply pipe 37 is connected to the first circulation pipe 35 via the branch pipe 35C, and the first end of the second supply pipe 80 is connected to the second circulation pipe 77 via the branch pipe 77C. In this regard, the first end of the first supply pipe 37 may be directly connected to the first tank T1. Also, the first end of the second supply pipe 80 may be directly connected to the second tank T2. [Explanation of symbols]

[0178] 1... Substrate processing equipment 2A, 2B, 2C ... Processing section 4... Standby temperature control unit 6... Treatment tank 31 ... spare circulation section 33...Main circulation section T1: First tank 35 … 1st circulation piping 36 ... First bypass pipe 37 … 1st supply piping 39 … Concentration piping 41...Quartz heater 43 ... First pump 45...Non-quartz heater 47 … Quartz tube 51 … Non-quartz tube 67 ... Bubble supply section T2: Second tank 77 … 2nd circulation piping 78... Second bypass piping 80,81,82 … 2nd supply piping 101,102,103 … 2nd supply piping 85 … Concentration piping 87...Quartz heater 89 ... Second pump 91...Non-quartz heater 93 ... Control section

Claims

1. a processing section having a processing tank for storing a phosphoric acid solution for immersing the substrate; a tank for storing the phosphoric acid solution; a supply flow path for delivering the phosphoric acid solution in the tank to the treatment section; a circulation flow path connected to the tank at both ends and configured to return the phosphoric acid solution flowing from the tank to the tank; a pump provided in the circulation flow path; a quartz heater provided in a concentration flow path that is a part of the circulation flow path, the quartz heater being made of quartz and having a quartz tube for passing the phosphoric acid solution; a bypass flow path, both ends of which are connected to the upstream end and downstream end of the concentration flow path; a non-quartz heater provided in the bypass flow path, the non-quartz heater having a non-quartz tube for passing the phosphoric acid solution, the non-quartz tube being not made of quartz; a control unit; When concentrating the phosphoric acid solution in the tank, the control unit heats the phosphoric acid solution passing through the concentration flow path using the quartz heater while sending the phosphoric acid solution to the concentration flow path, The substrate processing apparatus is characterized in that, when concentration of the phosphoric acid solution in the tank is completed, the control unit maintains the temperature of the phosphoric acid solution in the tank by heating the phosphoric acid solution passing through the bypass flow path using the non-quartz heater while sending the phosphoric acid solution to the bypass flow path.

2. 2. The substrate processing apparatus according to claim 1, Further provided is a phosphoric acid concentration sensor for measuring the concentration of the phosphoric acid solution in the tank; When the concentration value measured by the phosphoric acid concentration sensor is smaller than a preset threshold value, the control unit concentrates the phosphoric acid solution in the tank, The control unit determines that concentration of the phosphoric acid solution in the tank is complete when the concentration value measured by the phosphoric acid concentration sensor is equal to or greater than the threshold value, and maintains the temperature of the phosphoric acid solution in the tank.

3. 3. The substrate processing apparatus according to claim 1, When concentrating the phosphoric acid solution in the tank, the control unit heats the phosphoric acid solution passing through the concentration flow path using the quartz heater so that the temperature of the phosphoric acid solution in the tank becomes a predetermined first temperature, The substrate processing apparatus is characterized in that, when maintaining the temperature of the phosphoric acid solution in the tank, the control unit uses the non-quartz heater to heat the phosphoric acid solution passing through the bypass flow path so that the temperature of the phosphoric acid solution in the tank becomes a second temperature lower than the first temperature.

4. 4. The substrate processing apparatus according to claim 3, The substrate processing apparatus is characterized in that the first temperature is equal to or higher than the boiling point of the phosphoric acid solution.

5. 5. The substrate processing apparatus according to claim 3, The substrate processing apparatus is characterized in that the second temperature is 100° C. or higher and lower than the boiling point of the phosphoric acid solution.

6. 6. The substrate processing apparatus according to claim 3, a supply passage heater provided in the supply passage for heating the phosphoric acid solution passing through the supply passage;

7. 7. The substrate processing apparatus according to claim 1, 1. A substrate processing apparatus, further comprising: a bubble supply unit disposed on a bottom wall side of the tank, the bubble supply unit having a plurality of holes and configured to supply bubbles into the tank from the plurality of holes.

8. 8. The substrate processing apparatus according to claim 1, The substrate processing apparatus, wherein the control unit supplies the phosphoric acid solution to the processing unit through the supply flow path while the substrate is being processed by immersing it in the processing bath.

9. 9. The substrate processing apparatus according to claim 1, A substrate processing apparatus characterized in that, when a substrate is processed by immersing the substrate in the processing tank, the control unit supplies the phosphoric acid solution to the processing unit through the supply flow path while discharging a portion of the phosphoric acid solution in the processing tank.

10. 10. The substrate processing apparatus according to claim 1, The substrate processing apparatus is characterized in that the non-quartz tube is a fluorine-based resin tube made of a fluorine-based resin.

11. 11. The substrate processing apparatus according to claim 1, a second tank disposed in a supply flow path for supplying the phosphoric acid solution from the tank to the processing section, the second tank storing the phosphoric acid solution sent from the tank; a second circulation flow path connected to the second tank at both ends thereof for returning the phosphoric acid solution flowing from the second tank to the second tank; a second pump provided in the second circulation flow path; a second quartz heater provided in a second concentration flow path that is a part of the second circulation flow path, the second quartz heater being made of quartz and having a second quartz tube for passing the phosphoric acid solution; a second bypass flow path, both ends of which are connected to the upstream end and downstream end of the second concentration flow path; a second non-quartz heater provided in the second bypass flow path, the second non-quartz heater having a second non-quartz tube for passing the phosphoric acid solution, the second non-quartz tube being not made of quartz; Equipped with When concentrating the phosphoric acid solution in the second tank, the control unit heats the phosphoric acid solution passing through the second concentration flow path using the second quartz heater while sending the phosphoric acid solution to the second concentration flow path, the control unit, when concentration of the phosphoric acid solution in the second tank is completed, maintains the temperature of the phosphoric acid solution in the second tank by heating the phosphoric acid solution passing through the second bypass flow path using the second non-quartz heater while sending the phosphoric acid solution to the second bypass flow path.

12. 11. The substrate processing apparatus according to claim 1, a second tank disposed in a supply flow path for supplying the phosphoric acid solution from the tank to the processing section, the second tank storing the phosphoric acid solution sent from the tank; a second circulation flow path connected to the second tank at both ends thereof for returning the phosphoric acid solution flowing from the second tank to the second tank; a second pump provided in the second circulation flow path; a second quartz heater provided in the second circulation flow path, the second quartz heater being made of quartz and having a second quartz tube for passing the phosphoric acid solution; Equipped with When concentrating the phosphoric acid solution in the tank, the control unit heats the phosphoric acid solution passing through the concentration flow path using the quartz heater so that the temperature of the phosphoric acid solution in the tank becomes a predetermined first temperature, The control unit maintains the temperature of the phosphoric acid solution in the second tank by using the second quartz heater to heat the phosphoric acid solution passing through the second circulation flow path so that the temperature of the phosphoric acid solution in the second tank becomes a second temperature lower than the first temperature, in order to maintain the concentration of the phosphoric acid solution.

13. 11. The substrate processing apparatus according to claim 1, a second tank disposed in a supply flow path for supplying the phosphoric acid solution from the tank to the processing section, the second tank storing the phosphoric acid solution sent from the tank; a second circulation flow path connected to the second tank at both ends thereof for returning the phosphoric acid solution flowing from the second tank to the second tank; a second pump provided in the second circulation flow path; a second quartz heater provided in the second circulation flow path, the second quartz heater being made of quartz and having a second quartz tube for passing the phosphoric acid solution; Equipped with When concentrating the phosphoric acid solution in the second tank, the control unit heats the phosphoric acid solution passing through the second circulation flow path using the second quartz heater so that the temperature of the phosphoric acid solution in the second tank becomes a predetermined first temperature, The control unit heats the phosphoric acid solution passing through the second circulation flow path using the second quartz heater so that, when concentration of the phosphoric acid solution in the second tank is completed, the temperature of the phosphoric acid solution in the second tank becomes a second temperature lower than the first temperature.

14. a processing section having a processing tank for storing a phosphoric acid solution for immersing the substrate; a tank for storing the phosphoric acid solution; a supply flow path for delivering the phosphoric acid solution in the tank to the treatment section; a circulation flow path connected to the tank at both ends and configured to return the phosphoric acid solution flowing from the tank to the tank; a pump provided in the circulation flow path; a quartz heater provided in the circulation flow path, the quartz heater being made of quartz and having a quartz tube through which the phosphoric acid solution passes; a control unit, When concentrating the phosphoric acid solution in the tank, the control unit heats the phosphoric acid solution passing through the circulation flow path using the quartz heater so that the temperature of the phosphoric acid solution in the tank becomes a predetermined first temperature, The control unit heats the phosphoric acid solution passing through the circulation flow path using the quartz heater so that the temperature of the phosphoric acid solution in the tank becomes a second temperature lower than the first temperature when concentration of the phosphoric acid solution in the tank is completed.

Images