Substrate processing apparatus and substrate processing method

Abstract

This invention provides a substrate processing apparatus and a substrate processing method. The substrate processing apparatus includes a processing unit, a storage unit, a processing circuit, a circulation circuit, and a gas supply circuit. The processing unit etches a polycrystalline silicon film or an amorphous silicon film formed on the substrate using an alkaline solution. The storage unit recovers and stores the solution used in the processing unit. The processing circuit supplies the solution stored in the storage unit to the processing unit. The circulation circuit removes the solution from the storage unit and returns the removed solution to the storage unit. The gas supply circuit is connected to the circulation circuit and supplies a non-reactive gas to the circulation circuit. The circulation circuit includes an outlet that discharges a mixture of the non-reactive gas supplied by the first gas supply circuit and the solution removed from the storage unit into the interior of the solution stored in the storage unit. Therefore, when the alkaline solution is recovered for reuse, the dissolved oxygen concentration of the solution can be efficiently reduced.

Description

Technical Field

[0001] This disclosure relates to a substrate processing apparatus and a substrate processing method. Background Technology

[0002] The substrate processing method described in Patent Document 1 etches a polycrystalline silicon film formed on a substrate by discharging a TMAH (tetramethylammonium hydroxide) solution containing dissolved oxygen from a nozzle. This substrate processing method controls the etching rate by dissolving oxygen in the TMAH solution.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2013-258391 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] One aspect of this disclosure provides a technique for efficiently reducing the dissolved oxygen concentration of a recycled alkaline solution during reuse.

[0008] Technical means for solving problems

[0009] One aspect of the substrate processing apparatus disclosed herein includes a processing unit, a storage unit, a processing circuit, a circulation circuit, and a gas supply circuit. The processing unit etches a polycrystalline silicon film or an amorphous silicon film formed on a substrate using an alkaline solution. The storage unit recovers and stores the solution used by the processing unit. The processing circuit supplies the solution stored in the storage unit to the processing unit. The circulation circuit removes the solution from the storage unit and returns the removed solution to the storage unit. The gas supply circuit is connected to the circulation circuit and supplies a non-reactive gas to the circulation circuit. The circulation circuit includes an outlet that discharges a mixture of the non-reactive gas supplied by the first gas supply circuit and the solution removed from the storage unit into the interior of the solution stored in the storage unit.

[0010] The effects of the invention

[0011] According to one aspect of this disclosure, in the case of recycling alkaline pharmaceutical solutions for reuse, the dissolved oxygen concentration of the pharmaceutical solution can be reduced efficiently. Attached Figure Description

[0012] Figure 1 This is a diagram illustrating a substrate processing apparatus according to one embodiment.

[0013] Figure 2 This is a diagram showing the processing unit of one implementation method.

[0014] Figure 3 This is a flowchart illustrating a substrate processing method in one implementation.

[0015] Figure 4 This is a cross-sectional view showing an example of a container connected to a storage section.

[0016] Figure 5 This is an example table showing the flow rate settings for each gas supply line.

[0017] Explanation of reference numerals in the attached figures

[0018] 1 Substrate Processing Device

[0019] 10 Processing Department

[0020] 20 Storage Department

[0021] 30 processing lines

[0022] 40-cycle circuit

[0023] 40b discharge outlet

[0024] 50 First Gas Supply Line Detailed Implementation

[0025] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Furthermore, in the drawings, the same or corresponding structures are labeled with the same reference numerals, and sometimes descriptions are omitted.

[0026] like Figure 1 The substrate processing apparatus 1 shown includes a processing unit 10. The processing unit 10 etches a polycrystalline silicon film formed on the substrate using an alkaline solution. Alternatively, an amorphous silicon film can be formed instead of a polycrystalline silicon film, and the solution can also be used to etch the amorphous silicon film.

[0027] like Figure 2 As shown, the processing unit 10 includes: a processing container 11; a holding part 12 that holds the substrate W horizontally; a rotating part 13 that rotates the holding part 12 about a vertical rotation axis 14; and a nozzle 16 that discharges liquid to the upper surface of the substrate W held by the holding part 12. Furthermore, in this embodiment, the processing unit 10 is a single-piece type that processes substrates W one by one, but it can also be a batch type that processes multiple substrates W simultaneously. In the batch type, the holding part 12 can also hold the substrate W vertically.

[0028] The processing container 11 houses the substrate W inside. The processing container 11 has a gate (not shown) and a gate valve (not shown) for opening and closing the gate. The substrate W is fed into the processing container 11 through the gate, treated with a chemical solution inside the processing container 11, and then discharged to the outside of the processing container 11 through the gate.

[0029] The holding section 12 horizontally holds the substrate W that has been fed into the processing container 11. The holding section 12 holds the substrate W horizontally with the polysilicon film side of the substrate W facing upwards and the center of the substrate W aligned with the rotation center line of the rotation axis 14. Figure 2 The chuck can be mechanical, but it can also be a vacuum chuck or an electrostatic chuck. The retaining part 12 can be any rotary chuck that can rotate.

[0030] The rotating part 13 includes, for example, a vertical rotating shaft 14 and a rotary motor 15 that rotates the rotating shaft 14. The rotational driving force of the rotary motor 15 can also be transmitted to the rotating shaft 14 via a rotational transmission mechanism such as a timing belt or gears. When the rotating shaft 14 is rotated, the holding part 12 also rotates.

[0031] The nozzle 16 supplies an alkaline solution to the substrate W held by the holding part 12. The nozzle 16 has a discharge port for discharging the solution. The nozzle 16 is disposed above the substrate W with the discharge port facing downwards. The nozzle 16 is capable of moving radially above the substrate W.

[0032] Nozzle 16 supplies a liquid medicine, for example, to the center of substrate W. The liquid medicine is supplied to the center of the rotating substrate W and wets and diffuses to the entire upper surface of substrate W by centrifugal force, forming a liquid film.

[0033] Use liquid film to etch polycrystalline silicon film.

[0034] The etching solution is, for example, a TMAH-containing solution. In this embodiment, the solution contains TMAH, but any solution capable of etching the polycrystalline silicon film is acceptable. For example, the solution could be an ammonia solution or a choline solution.

[0035] In addition to discharging the etching solution, nozzle 16 can also discharge rinsing solution and drying solution. The liquids used to treat the substrate W, such as the etching solution, rinsing solution, and drying solution, are also referred to as "processing solutions". One nozzle 16 can discharge multiple processing solutions sequentially, or different processing solutions can be discharged from multiple nozzles 16.

[0036] The rinsing solution is, for example, DIW (deionized water). The rinsing solution is used to remove the chemical solution. It is supplied to the center of a rotating substrate W and, through centrifugal force, wets and spreads to the entire upper surface of the substrate W, rinsing away any remaining chemical solution. As a result, a liquid film of the rinsing solution is formed on the upper surface of the substrate W.

[0037] The drying solution is, for example, an organic solvent such as IPA (isopropanol). Organic solvents have a lower surface tension than rinsing solutions. Therefore, they can suppress the collapse of the raised pattern caused by surface tension. The drying solution is supplied to the center of the rotating substrate W and, through centrifugal force, wets and spreads to the entire upper surface of the substrate W, displacing the rinsing solution remaining on the upper surface of the substrate W. As a result, a liquid film of drying solution is formed on the upper surface of the substrate W.

[0038] Alternatively, nozzle 16 can discharge a solution different from the etching solution; for example, a cleaning solution can be discharged before the etching solution. The cleaning solution can be used to remove contaminants from the polycrystalline silicon film before etching. Examples of cleaning solutions include DHF (dilute hydrofluoric acid), SC-1 (an aqueous solution containing ammonium hydroxide and hydrogen peroxide), or SC-2 (an aqueous solution containing hydrogen chloride and hydrogen peroxide).

[0039] The processing unit 10 has a cup 17 for recovering the liquid medicine supplied to the substrate W. The cup 17 surrounds the periphery of the substrate W of the holding unit 12 and receives the liquid medicine or the like that that spills from the periphery of the substrate W. In this embodiment, the cup 17 does not rotate with the rotation axis 14, but it may rotate with the rotation axis 14.

[0040] The cup body 17 includes: a horizontal bottom wall 17a; an outer peripheral wall 17b extending upward from the periphery of the bottom wall 17a; and an inclined wall 17c extending radially inward and obliquely upward from the upper end of the outer peripheral wall 17b toward the outer peripheral wall 17b. A drain pipe 17d for discharging liquid accumulated inside the cup body 17 and an exhaust pipe 17e for discharging gas accumulated inside the cup body 17 are provided on the bottom wall 17a.

[0041] like Figure 1 As shown, the substrate processing apparatus 1 includes a control unit 90. The control unit 90 is, for example, a computer, including a CPU (Central Processing Unit) 91 and a storage medium 92 such as a memory. The storage medium 92 stores programs for controlling various processes to be executed in the substrate processing apparatus 1. The control unit 90 controls the operation of the substrate processing apparatus 1 by causing the CPU 91 to execute the programs stored in the storage medium 92.

[0042] Next, refer to Figure 3 The substrate processing method is explained. Figure 3 Each step S101 to S106 shown is performed under the control of the control unit 90.

[0043] First, in S101, a conveying device (not shown) delivers the substrate W into the processing container 11.

[0044] After the conveying device places the substrate W onto the holding part 12, it withdraws from the inside of the processing container 11. The holding part 12 receives the substrate W from the conveying device and holds the substrate W. Then, the rotating part 13 rotates the substrate W together with the holding part 12.

[0045] Next, in S102, nozzle 16 supplies a chemical solution to the center of the rotating substrate W. The chemical solution wets and spreads across the entire upper surface of the substrate W due to centrifugal force, forming a liquid film. This liquid film etches the polycrystalline silicon film formed on the substrate W.

[0046] Next, in S103, nozzle 16 supplies rinsing fluid to the center of the rotating substrate W.

[0047] The rinsing solution wets and spreads across the entire upper surface of substrate W through centrifugal force, rinsing away any residual medication on the upper surface of substrate W. As a result, a liquid film of rinsing solution is formed on the upper surface of substrate W.

[0048] Next, in S104, nozzle 16 supplies drying liquid to the center of the rotating substrate W. The drying liquid wets and spreads to the entire upper surface of the substrate W by centrifugal force, rinsing off any remaining rinsing liquid on the upper surface of the substrate W. As a result, a liquid film of drying liquid is formed on the upper surface of the substrate W.

[0049] Next, in S105, the rotating unit 13 rotates the substrate W to remove the drying liquid remaining on the upper surface of the substrate W, thereby drying the substrate W. After the substrate W is dried, the rotating unit 13 stops rotating the substrate W.

[0050] Next, in S106, the holding part 12 releases the substrate W from the holding part, and then the conveying device (not shown) receives the substrate W from the holding part 12 and sends the received substrate W to the outside of the processing container 11.

[0051] Alternatively, it can be omitted. Figure 3 This is part of the process shown. For example, the supply of drying liquid may not be performed (S104). In this case, the rinsing liquid is then supplied (S103), and the substrate W is dried (S105), with the rinsing liquid remaining on the substrate W being thrown off by centrifugal force.

[0052] Next, refer to again Figure 1 The peripheral devices of the processing unit 10 will be described below. The substrate processing apparatus (1) includes: a storage unit (20) that recovers and stores the liquid medicine used by the processing unit (10); and a processing line (30) that supplies the liquid medicine stored in the storage unit (20) to the processing unit (10). The storage unit 20 is, for example, a tank.

[0053] Processing line 30 connects, for example, the circulation line 40 (described later) to processing unit 10. The upstream end of processing line 30 is connected to circulation line 40, and the downstream end of processing line 30 is connected to nozzle 16 of processing unit 10. Processing line 30 is provided for each processing unit 10.

[0054] An on / off valve 31 for opening and closing the flow path of the processing line 30, a flow regulator 32 for adjusting the flow rate of the processing line 30, and a flow meter 33 for measuring the flow rate of the processing line 30 are installed midway through the processing line 30. The operation of the on / off valve 31 and the flow regulator 32 are controlled by the control unit 90. The flow meter 33 sends a signal indicating the measurement result to the control unit 90.

[0055] When the on / off valve 31 opens the flow path, the nozzle 16 discharges the liquid medicine. The flow rate of the liquid medicine is measured by the flow meter 33, and the control unit 90 controls the flow regulator 32 to make its measured value the set value. On the other hand, when the on / off valve 31 closes the flow path, the nozzle 16 stops discharging the liquid medicine.

[0056] The substrate processing apparatus 1 also includes a circulation line 40. The circulation line 40 takes out the liquid medicine from the storage unit 20 and returns the taken out liquid medicine to the storage unit 20. The upstream end 40a of the circulation line 40 is connected to the storage unit 20, and the downstream end 40b of the circulation line 40 is also connected to the storage unit 20.

[0057] A pump 41 for dispensing the medicine, a filter 42 for collecting impurities in the medicine, a heater 43 for heating the medicine, and a thermometer 45 for measuring the temperature of the medicine are provided midway through the circulation circuit 40. The control unit 90 controls the heater 43 so that the measurement value of the thermometer 45 is the set value. This allows the medicine at the desired temperature to be supplied to the substrate W.

[0058] Furthermore, the etching rate of the polycrystalline silicon film on substrate W using the etching solution is determined by factors such as the dissolved oxygen concentration of the solution. Dissolved oxygen refers to molecular oxygen (O2) dissolved in a liquid. The higher the dissolved oxygen concentration (unit: mg / L), the easier it is for the polycrystalline silicon film to be oxidized, and the easier it is to form an oxide film.

[0059] When the etching solution contains TMAH, the more advanced the oxidation of the polycrystalline silicon film, the slower the etching rate of the polycrystalline silicon film. This is because TMAH-containing solutions are not good at etching oxide films.

[0060] Therefore, when the solution contains TMAH, the higher the dissolved oxygen concentration of the solution, the slower the etching rate of the polycrystalline silicon film based on the solution. This tendency is contrary to that described in Patent Document 1.

[0061] Furthermore, when the chemical solution is ammonia or choline, the more advanced the oxidation of the polycrystalline silicon film, the faster the etching rate of the polycrystalline silicon film. This is because ammonia and choline solutions readily etch the oxide film.

[0062] Therefore, when the solution is an ammonia solution or a choline solution, the higher the dissolved oxygen concentration of the solution, the faster the etching rate of the polycrystalline silicon film based on the solution.

[0063] After the liquid medicine is discharged from the nozzle 16 of the processing section 10, it returns to the storage section 20. During this period, the liquid medicine comes into contact with air, and the oxygen contained in the air dissolves in the liquid medicine, so the dissolved oxygen concentration of the liquid medicine becomes higher.

[0064] Therefore, the substrate processing apparatus 1 also includes a first gas supply line 50. The first gas supply line 50 is connected to the circulation line 40 and supplies inert gases such as N2 gas to the circulation line 40. A mixed fluid of the supplied inert gas and the liquid is formed.

[0065] The circulation line 40 includes an outlet 40b that discharges a mixture of inert gas supplied by the first gas supply line 50 and the liquid medicine taken from the storage section 20 into the interior of the liquid medicine stored in the storage section 20. A large number of inert gas bubbles are generated inside the storage section 20. The large contact area between the inert gas and the liquid medicine allows for efficient dissolution of the inert gas, and oxygen in the liquid medicine is effectively released into the inert gas according to Henry's Law. Therefore, the dissolved oxygen concentration of the liquid medicine can be effectively reduced.

[0066] The circulation circuit 40 also allows the mixture of inert gas and liquid medicine to collide with the bottom wall of the storage section 20, thereby refining the bubbles of the inert gas. This increases the specific surface area of ​​the bubbles and the contact area between the inert gas and the liquid medicine. Furthermore, the bubbles rise to the surface of the liquid medicine after reaching the bottom wall of the storage section 20, thus taking a longer time to reach the surface. Therefore, the dissolved oxygen concentration of the liquid medicine can be effectively reduced.

[0067] The circulation line 40 may also have a connection point 40d with the first gas supply line 50 located downstream of the connection points 40c with each processing line 30. Connection point 40d is positioned downstream of all connection points 40c. This allows for the supply of a solution with the same dissolved oxygen concentration to all processing units 10.

[0068] The first gas supply line 50 includes, for example, a common line 50a and multiple individual lines 50b. The downstream end of the common line 50a is connected to the circulation line 40, and the upstream end of the common line 50a is connected to each individual line 50b. Each individual line 50b is equipped with an on / off valve 51 for opening and closing the flow path of the individual line 50b, a flow regulator 52 for adjusting the flow rate of the individual line 50b, and a flow meter 53 for measuring the flow rate of the individual line 50b. The operation of the on / off valve 51 and the flow regulator 52 are controlled by the control unit 90. The flow meter 53 sends a signal indicating the measurement result to the control unit 90.

[0069] When the on / off valve 51 opens the flow path, the first gas supply line 50 supplies inert gas to the circulation line 40, generating a large number of inert gas bubbles inside the storage section 20. The flow rate of the inert gas is measured by the flow meter 53, and the control unit 90 controls the flow regulator 52 to make its measured value equal to the set values ​​Q1 and Q2. Different set values ​​Q1 and Q2 (Q2 > Q1) are set for each individual line 50b. On the other hand, when the on / off valve 51 closes the flow path, the first gas supply line 50 stops supplying inert gas to the circulation line 40.

[0070] In addition, in this embodiment, in order to smoothly switch the flow rate of the inactive gas, the first gas supply line 50 has two separate lines 50b, each of which is equipped with an on / off valve 51, a flow regulator 52, and a flow meter 53. However, the technology disclosed herein is not limited to this. Alternatively, one on / off valve 51, one flow regulator 52, and one flow meter 53 may be provided in each of the first gas supply lines 50.

[0071] The substrate processing apparatus 1 includes: a container 55 connected to a storage unit 20; a liquid recovery line 56 connected to the container 55; and a second gas supply line 60 connected to the container 55. The container 55 temporarily holds the liquid and transports it to the storage unit 20. The liquid recovery line 56 returns the liquid used in the processing unit 10 to the storage unit 20 via the container 55. The second gas supply line 60 supplies a non-reactive gas, such as N2 gas, into the container 55.

[0072] According to this embodiment, after the liquid medicine is discharged from the nozzle 16 of the processing unit 10, it is temporarily stored in the container 55 before returning to the storage unit 20. The interior of the container 55 is filled with inert gas by the second gas supply line 60. The inert gas dissolves in the liquid medicine, and the oxygen in the liquid medicine is released into the inert gas according to Henry's Law. Therefore, the dissolved oxygen concentration of the liquid medicine can be brought close to its original concentration before returning it to the storage unit 20.

[0073] The liquid medicine recovery line 56 includes, for example, a common line 56a and multiple individual lines 56b. The common line 56a is connected to the container 55. Each individual line 56b connects the common line 56a to the processing unit 10 and sends the liquid medicine recovered from the cup 17, etc., in the processing unit 10 to the common line 56a.

[0074] An on / off valve 61 for opening and closing the flow path of the second gas supply line 60, a flow regulator 62 for adjusting the flow rate of the second gas supply line 60, and a flow meter 63 for measuring the flow rate of the second gas supply line 60 are installed midway through the second gas supply line 60. The operation of the on / off valve 61 and the flow regulator 62 are controlled by the control unit 90. The flow meter 63 sends a signal indicating the measurement result to the control unit 90.

[0075] When the on / off valve 61 opens the flow path, the second gas supply line 60 supplies inert gas to the interior of the container 55. The flow rate of the inert gas is measured by the flow meter 63, and the control unit 90 controls the flow regulator 62 to make its measured value the set value Q3. On the other hand, when the on / off valve 61 closes the flow path, the second gas supply line 60 stops supplying inert gas to the container 55.

[0076] The substrate processing apparatus 1 also includes a solution supply line 66 connected to the container 55. The solution supply line 66 supplies the solution used by the processing unit 10 before it was degraded due to the etching of the substrate W to the storage unit 20 via the container 55. As a result, the interior of the storage unit 20 changes from an empty state to a state where the liquid level of the solution reaches a preset height.

[0077] The storage compartment 20 becomes empty when the substrate processing apparatus 1 is started or when the degraded reagent is replaced. The degraded reagent has a higher silicon concentration than the undegraded reagent, such as an unused reagent, and is discharged to the outside of the storage compartment 20 via the drain line 21. In addition, the gas accumulated inside the storage compartment 20 is discharged to the outside of the storage compartment 20 via the exhaust line 22.

[0078] According to this embodiment, unused medicine is temporarily stored in container 55 before being supplied to storage unit 20. The interior of container 55 is filled with inert gas via the second gas supply line 60. The inert gas dissolves in the medicine, and oxygen in the medicine is released into the inert gas according to Henry's Law. Therefore, the dissolved oxygen concentration of the medicine can be made close to the desired concentration before supplying unused medicine to storage unit 20.

[0079] An on / off valve 67 for opening and closing the flow path of the liquid medicine supply line 66, a flow regulator 68 for adjusting the flow rate of the liquid medicine supply line 66, and a flow meter 69 for measuring the flow rate of the liquid medicine supply line 66 are installed midway through the line. The operation of the on / off valve 67 and the flow regulator 68 are controlled by the control unit 90. The flow meter 69 sends a signal indicating the measurement result to the control unit 90.

[0080] When the on / off valve 67 opens the flow path, the liquid supply line 66 supplies liquid medicine to the interior of the container 55. The flow rate of the liquid medicine is measured by the flow meter 69, and the control unit 90 controls the flow regulator 68 to make its measured value the set value. On the other hand, when the on / off valve 67 closes the flow path, the liquid supply line 66 stops supplying liquid medicine to the container 55.

[0081] Next, refer to Figure 4 The structure of container 55 will be described. Container 55 is provided, for example, at the top of storage section 20. Container 55 has a wall 55c with openings 55a and 55b that communicate with the interior of container 55 and the interior of storage section 20. Wall 55c is provided, for example, horizontally at the top of storage section 20.

[0082] The openings 55a and 55b of wall 55c are offset from the extension line E1 of the liquid recovery line 56. The extension line E1 is, for example, vertical, so the liquid immediately falls downwards. Wall 55c receives the liquid returned to container 55 by the liquid recovery line 56 and splashes it. As a result, a large number of liquid droplets are formed, increasing the specific surface area of ​​the liquid. The increased contact area between the liquid and the inert gas allows the inert gas to dissolve effectively in the liquid, and oxygen in the liquid is effectively released into the inert gas according to Henry's Law. Therefore, the dissolved oxygen concentration of the liquid can be effectively reduced.

[0083] Furthermore, the openings 55a and 55b of wall 55c are staggered from the extension line E2 of the liquid supply line 66. The extension line E2 is, for example, vertical, so the liquid immediately falls downwards.

[0084] The wall 55c receives and rebounds the liquid medicine supplied to the container 55 by the liquid medicine supply line 66. As a result, a large number of liquid medicine droplets are formed, increasing the specific surface area of ​​the liquid medicine. The increased contact area between the liquid medicine and the inert gas allows the inert gas to dissolve effectively in the liquid medicine, and the oxygen in the liquid medicine is effectively released into the inert gas according to Henry's Law. Therefore, the dissolved oxygen concentration of the liquid medicine can be effectively reduced.

[0085] Furthermore, the openings 55a and 55b of wall 55c are offset from the extension line E3 of the flow path of the second gas supply line 60. The extension line E3 is, for example, vertical, allowing the inert gas to immediately fall downwards. Wall 55c receives the inert gas supplied to container 55 by the second gas supply line 60. As a result, the inert gas is easily dispersed. The inert gas dissolves effectively in the liquid, and oxygen in the liquid is effectively released into the inert gas according to Henry's Law. Therefore, the dissolved oxygen concentration of the liquid can be effectively reduced.

[0086] like Figure 1 As shown, the substrate processing apparatus 1 also includes a third gas supply line 70 connected to the storage section 20. Unlike the second gas supply line 60, the third gas supply line 70 supplies inert gases such as N2 gas to the interior of the storage section 20 without passing through the container 55. Furthermore, unlike the circulation line 40, the third gas supply line 70 has an outlet 70a for inert gases in the space above the liquid level of the accumulated drug solution inside the storage section 20 (the upper space of the storage section 20).

[0087] An on / off valve 71 for opening and closing the flow path of the third gas supply line 70, a flow regulator 72 for adjusting the flow rate of the third gas supply line 70, and a flow meter 73 for measuring the flow rate of the third gas supply line 70 are installed midway through the line. The operation of the on / off valve 71 and the flow regulator 72 are controlled by the control unit 90. The flow meter 73 sends a signal indicating the measurement result to the control unit 90.

[0088] When the on / off valve 71 opens the flow path, the third gas supply line 70 supplies inert gas to the interior of the storage unit 20. The flow rate of the inert gas is measured by the flow meter 73, and the control unit 90 controls the flow regulator 72 to make its measured value equal to the set value Q4. On the other hand, when the on / off valve 71 closes the flow path, the third gas supply line 70 stops supplying inert gas to the storage unit 20.

[0089] In addition, the substrate processing apparatus 1 also includes a fourth gas supply line 80. The fourth gas supply line 80 is connected to the liquid recovery line 56 and supplies inert gases such as N2 to the liquid recovery line 56. The interior of the liquid recovery line 56 is filled with inert gases, which can prevent air from flowing from the processing unit 10 into the liquid recovery line 56 and can suppress contact between air and the liquid. Therefore, it can suppress the increase in the dissolved oxygen concentration of the liquid.

[0090] The fourth gas supply line 80 is connected to the common line 56a of the liquid recovery line 56, supplying inert gas to the common line 56a. The fourth gas supply line 80 is connected to the common line 56a upstream of each individual line 56b. The common line 56a can be completely filled with inert gas, which can suppress the inflow of air from the entire processing unit 10 into the liquid recovery line 56.

[0091] An on / off valve 81 for opening and closing the flow path of the fourth gas supply line 80, a flow regulator 82 for adjusting the flow rate of the fourth gas supply line 80, and a flow meter 83 for measuring the flow rate of the fourth gas supply line 80 are installed midway through the line. The operation of the on / off valve 81 and the flow regulator 82 are controlled by the control unit 90. The flow meter 83 sends a signal indicating the measurement result to the control unit 90.

[0092] When the on / off valve 81 opens the flow path, the fourth gas supply line 80 supplies inert gas to the liquid recovery line 56. The flow rate of the inert gas is measured by the flow meter 83, and the control unit 90 controls the flow regulator 82 to make its measured value the set value Q5. On the other hand, when the on / off valve 81 closes the flow path, the fourth gas supply line 80 stops supplying inert gas to the liquid recovery line 56.

[0093] Next, refer to Figure 5 The flow rate settings for each gas supply line are explained. Figure 5 In this context, N represents the number of processing lines 30 in operation, which can be an integer between 1 and 5. The number of processing lines 30 in operation refers to the number of processing lines 30 in the state where the flow path is open by the on / off valve 31 and the liquid is being discharged from the nozzle 16. Furthermore, the number of processing units 10 and the number of processing lines 30 are not limited to 5; 2 or more are acceptable. The maximum value of N is equal to the number of processing lines 30.

[0094] The liquid storage mode is a state in which unused medicine liquid accumulates inside the storage section 20. In the liquid storage mode, the medicine supply line 66 supplies unused medicine liquid to the storage section 20. Additionally, in the liquid storage mode, the circulation line 40 removes medicine liquid from the storage section 20, returning the removed medicine liquid to the storage section 20. In the liquid storage mode, because the amount of medicine liquid inside the storage section 20 is insufficient, the processing line 30 stops supplying medicine liquid to the processing section 10.

[0095] The unused pharmaceutical solution supplied to the storage unit 20 in the liquid storage mode has a high dissolved oxygen concentration, similar to the pharmaceutical solution recovered from the processing unit 10 to the storage unit 20 in the substrate processing mode (described later). Furthermore, the unused pharmaceutical solution supplied to the storage unit 20 in the liquid storage mode has a higher flow rate compared to the pharmaceutical solution recovered from the processing unit 10 to the storage unit 20 in the substrate processing mode.

[0096] Therefore, in the liquid storage mode, compared to the substrate processing mode, the flow rate of inert gas supplied by the first gas supply line 50 to the circulation line 40 is greater. This allows the dissolved oxygen concentration of unused solution to be reduced to the desired concentration in a short time.

[0097] In addition, in the liquid storage mode, the liquid supply line 66 supplies unused liquid to the storage unit 20 via the container 55. Then, the second gas supply line 60 supplies inert gas to the interior of the container 55. Furthermore, the third gas supply line 70 supplies inert gas to the interior of the storage unit 20.

[0098] In liquid storage mode, processing line 30 stops supplying the chemical solution to processing unit 10, so the chemical solution will not flow from processing unit 10 into chemical solution recovery line 56. Therefore, the fourth gas supply line 80 stops supplying inert gas to chemical solution recovery line 56. Unnecessary use of inert gas can be prevented. In addition, in liquid storage mode, compared with substrate processing mode, if the flow rate of inert gas supplied by the fourth gas supply line 80 to chemical solution recovery line 56 is less, the use of unnecessary inert gas can be suppressed.

[0099] Standby mode refers to a state where the desired amount of medicine is stored inside the storage unit 20, the medicine supply line 66 stops supplying medicine to the storage unit 20, and the processing line 30 stops supplying medicine to the processing unit 10. In standby mode, the circulation line 40 removes medicine from the storage unit 20 and returns the removed medicine to the storage unit 20. The temperature of the medicine is maintained at the desired temperature.

[0100] In standby mode, processing line 30 stops supplying liquid medicine to processing unit 10, so the liquid medicine will not flow from processing unit 10 into liquid medicine recovery line 56. Therefore, fourth gas supply line 80 stops supplying inert gas to liquid medicine recovery line 56. This prevents the unnecessary use of inert gas.

[0101] In standby mode, both the liquid recovery line 56 and the liquid supply line 66 stop supplying liquid to the storage section 20 via container 55. Therefore, the second gas supply line 60 stops supplying inert gas to the interior of container 55. This prevents unnecessary use of inert gas. Additionally, the first gas supply line 50 stops supplying inert gas to the circulation line 40.

[0102] In standby mode, the third gas supply line 70 supplies inert gas to the interior of the storage section 20. This prevents external air from entering the upper space of the storage section 20 and prevents air from contacting the liquid medicine.

[0103] The substrate processing mode refers to a state in which the desired amount of liquid medicine is stored inside the storage unit 20, the liquid medicine supply line 66 stops supplying liquid medicine to the storage unit 20, and the processing line 30 supplies liquid medicine to the processing unit 10. In the substrate processing mode, the circulation line 40 removes liquid medicine from the storage unit 20, returning the removed liquid medicine to the storage unit 20.

[0104] In the substrate processing mode, processing line 30 supplies a chemical solution to processing unit 10, and as a result, the chemical solution flows from processing unit 10 into chemical solution recovery line 56. Then, fourth gas supply line 80 supplies a non-reactive gas to chemical solution recovery line 56.

[0105] In the substrate processing mode, the liquid recovery line 56 supplies liquid to the storage unit 20 via the container 55. Then, the second gas supply line 60 supplies inert gas to the interior of the container 55. Additionally, the first gas supply line 50 supplies inert gas to the circulation line 40.

[0106] However, in substrate processing mode, the flow rate of the liquid returning from the liquid recovery line 56 to the storage unit 20 changes accordingly to the number of operations of the processing line 30. Therefore, the control unit 90 can also control the flow rate of the inert gas supplied to the circulation line 40 via the first gas supply line 50 based on the number of operations of the processing line 30. The more operations the processing line 30 has, the higher the flow rate of the inert gas is set. The number of operations of the processing line 30 can be determined, for example, based on the number of open / closed valves 31.

[0107] Additionally, the control unit 90 can also control the flow rate of the inert gas supplied to the circulation line 40 through the first gas supply line 50 based on the total flow rate of the processing line 30. The higher the total flow rate of the processing line 30, the higher the flow rate of the inert gas can be set. The total flow rate of the processing line 30 is measured by multiple flow meters 33.

[0108] In substrate processing mode, the third gas supply line 70 supplies inert gas to the interior of the storage section 20. This prevents external air from entering the upper space of the storage section 20 and prevents air from contacting the liquid medicine.

[0109] When the substrate processing apparatus 1 is started, its state sequentially transitions between liquid storage mode and standby mode. Afterward, the state of the substrate processing apparatus 1 alternates between substrate processing mode and standby mode. When the chemical solution deteriorates, the chemical solution inside the storage section 20 is drained, and the chemical solution is replaced.

[0110] When the chemical solution is replaced, the state of the substrate processing device 1 sequentially switches between the liquid storage mode and the standby mode. Afterward, the state of the substrate processing device 1 alternates between the substrate processing mode and the standby mode. When the chemical solution deteriorates, the chemical solution inside the storage section 20 is discharged again, and the chemical solution is replaced.

[0111] The embodiments of the substrate processing apparatus and substrate processing method of this disclosure have been described above, but this disclosure is not limited to the above embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. These are naturally included within the technical scope of this invention.

Claims

1. A substrate processing apparatus, characterized in that, include: A processing section that uses an alkaline solution to etch polycrystalline silicon or amorphous silicon films formed on a substrate; A storage unit for recovering and storing the pharmaceutical solution used in the processing unit; The processing line supplies the liquid medicine stored in the storage section to the processing section; The medicine is taken out from the storage unit and the taken-out medicine is returned to the storage unit via a circulation circuit. and A first gas supply line, connected to the circulation line, supplies inert gas to the circulation line. The circulation circuit includes a discharge port that discharges a mixture of inert gas supplied by the first gas supply line and the liquid medicine taken from the storage unit into the interior of the storage unit containing the liquid medicine. The substrate processing apparatus further includes: A flow regulator that regulates the flow rate of the inert gas supplied to the circulation line via the first gas supply line; The control unit that controls the flow regulator; A container connected to the storage section, capable of temporarily holding the liquid medicine and transporting the liquid medicine to the storage section; A liquid medicine recovery line, connected to the container, allows the liquid medicine used by the processing unit to be returned to the storage unit via the container; and A second gas supply line, connected to the container, supplies inert gas into the container. The container has a wall with an opening that communicates the interior of the container with the interior of the storage section. The opening is staggered from the extension of the flow path of the liquid medicine recovery line. The wall receives the liquid medicine returned to the container via the liquid medicine recovery line and splashes the liquid medicine.

2. The substrate processing apparatus as described in claim 1, characterized in that: The processing unit is provided in multiple ways. The processing line is provided for each of the processing units. The control unit controls the flow regulator of the first gas supply line based on the number of operations of the processing line or the total flow of the processing line.

3. The substrate processing apparatus as described in claim 1 or 2, characterized in that: It includes a liquid medicine supply line connected to the container, which supplies the liquid medicine to the storage unit via the container before the processing unit uses it.

4. The substrate processing apparatus as described in claim 3, characterized in that: The opening is staggered from the extension of the flow path of the liquid medicine supply line. The wall receives the liquid medicine supplied to the container via the liquid medicine supply line and causes the liquid medicine to splash.

5. The substrate processing apparatus as described in claim 3, characterized in that: The control unit performs control such that, compared to the substrate processing mode where the liquid supply line stops supplying the liquid to the container and the processing line supplies the liquid to the processing unit, in the liquid storage mode where the liquid supply line supplies the liquid to the container and the processing line stops supplying the liquid to the processing unit, the flow rate of the inactive gas supplied by the first gas supply line to the circulation line is greater.

6. The substrate processing apparatus as described in claim 3, characterized in that: This includes a third gas supply line connected to the storage unit, which supplies inert gas to the storage unit without passing through the container. The control unit performs control so that, in a standby mode where the liquid supply line stops supplying the liquid to the container and the processing line stops supplying the liquid to the processing unit, the third gas supply line supplies an inert gas to the storage unit.

7. The substrate processing apparatus as described in claim 5, characterized in that: It includes a fourth gas supply line, which is connected to the liquid medicine recovery line and supplies inert gas to the liquid medicine recovery line.

8. The substrate processing apparatus as described in claim 7, characterized in that: The control unit performs control so that, in the liquid storage mode, the flow rate of inert gas supplied by the fourth gas supply line to the liquid recovery line is less than that in the substrate processing mode.

9. A substrate processing method, characterized in that, have: The process involves etching a polycrystalline silicon film or amorphous silicon film formed on a substrate using an alkaline solution in the processing section. The step of recovering the drug solution used in the processing unit and storing it in the storage unit; The step of supplying the liquid medicine stored in the storage unit to the processing unit via a processing line; The step of returning the liquid medicine stored in the storage unit to the storage unit via a circulation circuit; and The step of supplying inert gas to the circulation line using a first gas supply line connected to the circulation line. The circulation circuit discharges a mixture of the inert gas supplied by the first gas supply line and the liquid medicine taken from the storage unit into the interior of the storage unit containing the liquid medicine. A container is connected to the storage section, which can temporarily hold the liquid medicine and transport it to the storage section. The substrate processing method has the following characteristics: The step of returning the used medicine solution from the processing unit to the storage unit via the container using a medicine solution recovery line connected to the container; and The step of supplying an inert gas into the interior of the container using a second gas supply line connected to the container. The container has a wall with an opening that communicates the interior of the container with the interior of the storage section. The opening is staggered from the extension of the flow path of the liquid medicine recovery line. The wall receives the liquid medicine returned to the container via the liquid medicine recovery line and splashes the liquid medicine.

10. The substrate processing method as described in claim 9, characterized in that: The processing unit is provided in multiple ways. The processing line is provided for each of the processing units. The flow rate of the inert gas supplied to the circulation line via the first gas supply line is controlled based on the number of operations of the processing line or the total flow rate of the processing line.

11. The substrate processing method as described in claim 9 or 10, characterized in that, include: The step of supplying the medicine solution to the storage unit via the container before it is used by the processing unit using a medicine supply line connected to the container.

12. The substrate processing method as described in claim 11, characterized in that: The opening is staggered from the extension of the flow path of the liquid medicine recovery line. The wall receives the liquid medicine supplied to the container via the liquid medicine supply line and causes the liquid medicine to splash.

13. The substrate processing method as described in claim 11, characterized in that: Compared to the substrate processing mode where the liquid supply line stops supplying the liquid to the container and the processing line supplies the liquid to the processing unit, in the liquid storage mode where the liquid supply line supplies the liquid to the container and the processing line stops supplying the liquid to the processing unit, the flow rate of the inactive gas supplied by the first gas supply line to the circulation line is greater.

14. The substrate processing method as described in claim 11, characterized in that: The method includes a step of supplying an inert gas to the storage unit without passing through the container via a third gas supply line connected to the storage unit. In the standby mode where the liquid supply line stops supplying the liquid to the container and the processing line stops supplying the liquid to the processing unit, the third gas supply line supplies inert gas to the storage unit.

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