Substrate processing device and substrate processing method

Abstract

The present invention provides a substrate processing apparatus and a substrate processing method. The substrate processing apparatus comprises: an etching processing unit that etches a substrate using an etching liquid; a discharge flow path for discharging the etching liquid from the etching processing unit; and a solid silica unit disposed in the discharge flow path. The solid silica unit includes: a plurality of solid silicas; and a silica container that contains the plurality of solid silicas and allows the etching liquid to pass through the container.

Description

[0001] This application corresponds to Japanese Patent Application No. 2021-013938 filed with the Japan Patent Office on January 29, 2021, and all disclosed contents of that application are incorporated herein by reference. Technical Field

[0002] The present invention relates to a substrate processing device for processing a substrate and a substrate processing method for processing a substrate.

[0003] Examples of substrates to be processed include semiconductor wafers, FPD (Flat Panel Display) substrates such as liquid crystal display devices and organic EL (Electroluminescence) display devices, optical disc substrates, magnetic disc substrates, magneto-optical disc substrates, photomask substrates, ceramic substrates, and solar cell substrates. Background Art

[0004] Silicon oxide dissolves in the phosphoric acid aqueous solution used in substrate etching. Therefore, to prevent the concentration of silicon oxide in the phosphoric acid aqueous solution (hereinafter sometimes referred to as "silicon concentration") from exceeding saturation and precipitating on the substrate, a method is used to adjust the silicon concentration by replenishing the phosphoric acid aqueous solution during the substrate etching process. This method requires a large amount of phosphoric acid aqueous solution to adjust the silicon concentration.

[0005] Therefore, Japanese Patent No. 5829444 and Japanese Patent No. 3788985 propose a method of reusing the phosphoric acid aqueous solution used in the etching process of the substrate.

[0006] Specifically, Japanese Patent No. 5829444 discloses a method of removing silicon oxide from a phosphoric acid aqueous solution by cooling the phosphoric acid aqueous solution in a storage tank using a temperature control mechanism to precipitate silicon oxide from the phosphoric acid aqueous solution and then filtering the phosphoric acid aqueous solution with a filter.

[0007] Japanese Patent No. 3788985 discloses a method of diluting a phosphoric acid aqueous solution used in an etching process by supplying purified water to the solution to precipitate silicon oxide, then filtering the solution through a filter. Thereafter, the water is evaporated from the solution to concentrate the solution, which is then supplied to an etching tank.

[0008] In the methods disclosed in Patent No. 5829444 and Patent No. 3788985, the filter may become clogged by filtering out precipitated silicon oxide, thus requiring the time and effort of regular filter replacement.

[0009] Furthermore, the method of Patent No. 5829444 requires cooling the entire reservoir tank to precipitate silicon oxide, while the method of Patent No. 3788985 requires evaporating the water in the phosphoric acid aqueous solution. Consequently, both the methods of Patent No. 5829444 and Patent No. 3788985 require a relatively long time for silicon oxide precipitation. Summary of the Invention

[0010] An object of the present invention is to provide a substrate processing apparatus and a substrate processing method capable of effectively reducing the silicon concentration in an etching solution.

[0011] One embodiment of the present invention provides a substrate processing apparatus comprising an etching unit for etching a substrate using an etching liquid; a discharge passage for discharging the etching liquid from the etching unit; and a solid silica unit disposed in the discharge passage. The solid silica unit includes a plurality of solid silicas and a silica container that contains the plurality of solid silicas and allows the etching liquid to pass through the container.

[0012] According to this substrate processing apparatus, the etching liquid used for etching the substrate is discharged from the etching processing unit into an exhaust flow path. The solid silica unit provided in the exhaust flow path includes a silica storage portion that accommodates a plurality of solid silicas. Therefore, the etching liquid contacts the plurality of solid silicas as it passes through the silica storage portion, thereby effectively cooling the etching liquid. Consequently, silicon oxide dissolved in the etching liquid precipitates and adheres to the surfaces of the plurality of solid silicas. This allows for rapid precipitation of silicon oxide from the etching liquid.

[0013] Furthermore, sufficiently large gaps can be formed between adjacent solid silica particles, which can prevent the gaps between adjacent solid silica particles from being clogged when silicon oxide is precipitated on the surface of the solid silica particles.

[0014] As a result, the silicon concentration in the etching solution can be reduced satisfactorily.

[0015] In one embodiment of the present invention, the solid silica is in the form of granules with corners. The inventors of this application have discovered that when using solid silica in the form of granules with corners, the etching solution is easily replaced around the corners, and therefore, silicon oxide is easily precipitated at the corners and their surroundings on the surface of the solid silica. Therefore, by using solid silica in the form of granules with corners, silicon oxide dissolved in the etching solution can be effectively precipitated. Examples of the shape of such solid silica include polyhedrons and tablets.

[0016] In one embodiment of the present invention, the particle size of the solid silica is greater than 1 mm and less than 10 mm. If the particle size of the solid silica is within this range, gaps of appropriate size are formed between adjacent solid silica particles. When silicon oxide precipitates on the surface of the solid silica, clogging of the gaps between adjacent solid silica particles can be further suppressed.

[0017] In one embodiment of the present invention, the silica container includes a cylindrical space filled with a plurality of the solid silicas. The exhaust flow path includes an upstream exhaust flow path connected to one end of the cylindrical space in the axial direction of the cylindrical space, and a downstream exhaust flow path connected to the other end of the cylindrical space in the axial direction.

[0018] According to this substrate processing apparatus, within the cylindrical space, the etching liquid flows from one axial end to the other. This improves the uniformity of the etching liquid's linear velocity at each axial position within the cylindrical space. This facilitates the overall precipitation of silicon oxide from the plurality of solid silicon dioxide layers within the cylindrical space. Consequently, the silicon concentration in the etching liquid can be effectively reduced.

[0019] In one embodiment of the present invention, the silicon dioxide storage portion includes a liquid storage portion that stores a plurality of solid silicon dioxides and stores an etching solution.

[0020] According to this substrate processing apparatus, the etching liquid discharged from the etching processing unit to the discharge flow path can be stored in the liquid reservoir, and silicon oxide can be precipitated from the etching liquid using a plurality of solid silicon dioxides. Therefore, even when a large amount of etching liquid is discharged from the etching processing unit, the silicon concentration in the etching liquid can be effectively reduced. Furthermore, the amount of etching liquid discarded can be reduced.

[0021] In one embodiment of the present invention, the substrate processing apparatus further includes a cooling unit for cooling the plurality of solid silicas. Therefore, by cooling the plurality of solid silicas beforehand, the etching liquid can be rapidly cooled as it passes through the solid silica unit, thereby enabling rapid precipitation of silicon oxide.

[0022] In one embodiment of the present invention, the cooling unit includes: a coolant supply channel for supplying coolant to the silica storage section; and a coolant discharge channel for discharging coolant from the silica storage section. According to this substrate processing apparatus, supplying coolant to the silica storage section enables cooling of multiple solid silicas. Therefore, compared to cooling multiple solid silicas from outside the silica storage section, solid silicas located relatively innermost within the silica storage section can be cooled more quickly. As a result, the silicon concentration in the etching solution can be effectively reduced.

[0023] In one embodiment of the present invention, the substrate processing apparatus further comprises: a concentration measuring unit that measures the silicon concentration in the etching liquid at a predetermined measurement position downstream of the solid silica unit in the exhaust flow path; an etching liquid tank that stores the etching liquid; and a exhaust flow path opening and closing unit that is provided downstream of the measurement position in the exhaust flow path and opens and closes the exhaust flow path.

[0024] The ability of the solid silica unit to remove silicon oxide from the etching solution (removal capacity) decreases as the etching solution continues to pass through the solid silica unit. Specifically, the etching solution is cooled by multiple solid silicas, causing the temperature of the multiple solid silicas to rise, thereby reducing the ability to cool the etching solution.

[0025] When the removal capability of the solid silica unit is sufficiently high, the silicon concentration of the etching solution after passing through the solid silica unit is sufficiently reduced. When the removal capability of the solid silica unit is not sufficiently high, the silicon concentration of the etching solution after passing through the solid silica unit is not sufficiently reduced.

[0026] According to this substrate processing apparatus, it is possible to cause the etching liquid to flow into the etching liquid tank or to stop the etching liquid from flowing into the etching liquid tank. Thus, for example, if the silicon concentration measured by the concentration measuring unit is below a predetermined threshold, the etching liquid flows into the etching liquid tank. If the silicon concentration measured by the concentration measuring unit exceeds the threshold, the discharge flow path opening and closing unit can open and close the discharge flow path to stop the flow of etching liquid into the etching liquid tank.

[0027] By opening and closing the discharge flow path in this manner, etching liquid is supplied to the etching liquid tank when the removal capacity of the solid silica unit is sufficiently high. On the other hand, if the removal capacity of the solid silica unit decreases and the silicon concentration of the etching liquid after passing through the solid silica unit exceeds a threshold value, the supply of etching liquid to the etching liquid tank is stopped. Therefore, etching liquid with a sufficiently reduced silicon concentration can be selectively recovered in the etching liquid tank. As a result, etching liquid with a well-reduced silicon concentration can be recovered.

[0028] In one embodiment of the present invention, the substrate processing device further comprises: a return flow path, which is connected in the exhaust flow path at the same position as the measurement position or at a position downstream of the measurement position, and returns the etching liquid to the upstream side of the solid silica unit in the exhaust flow path; and a return flow path opening and closing unit, which opens and closes the return flow path.

[0029] According to this substrate processing apparatus, the etching liquid can be caused to flow into the return flow path, or the flow of the etching liquid into the return flow path can be stopped. For example, if the silicon concentration measured by the concentration measurement unit is below a threshold value, the flow of the etching liquid into the return flow path is stopped. If the silicon concentration measured by the concentration measurement unit exceeds the threshold value, the return flow path opening and closing unit can open and close the return flow path so that the etching liquid flows into the return flow path.

[0030] By opening and closing the return flow path in this manner, the etching liquid that has returned to the discharge flow path via the return flow path can be re-passed through the silica storage section of the solid silica unit. This further precipitates silicon oxide from the etching liquid, reducing the silicon concentration in the etching liquid. By repeatedly passing through the solid silica unit, the silicon concentration drops below a threshold, and the flow of etching liquid into the return flow path is stopped. Thus, etching liquid with a sufficiently reduced silicon concentration can be quickly flowed into the etching liquid tank. As a result, etching liquid with a well-reduced silicon concentration can be recovered.

[0031] In one embodiment of the present invention, the substrate processing device further comprises: a branch flow path, which branches from a position in the exhaust flow path that is downstream of the return position where the etching liquid returns from the return flow path and upstream of the solid silica unit, and is connected to a position that is downstream of the solid silica unit and upstream of the measurement position; and a branch flow path opening and closing unit that opens and closes the branch flow path.

[0032] According to this substrate processing apparatus, the etching liquid returned to the return position via the return flow path can be caused to flow into the branch flow path, or the etching liquid returned to the return position via the return flow path can be stopped from flowing into the branch flow path. Therefore, for example, if the silicon concentration measured by the concentration measurement unit exceeds a predetermined threshold, the branch flow path opening and closing unit can be operated to open and close the branch flow path so that the etching liquid returned to the return position via the return flow path flows into the branch flow path within a predetermined recovery time. By opening and closing the branch flow path in this manner, the supply of etching liquid to the solid silica unit can be stopped, and the etching liquid can be circulated within the branch flow path and the return flow path.

[0033] Therefore, for example, while the etching liquid is circulating in the branch flow path and the return flow path, the plurality of solid silicas in the silica storage unit can be cooled or replaced with sufficiently cooled solid silicas. After a predetermined period of time, the etching liquid can be stopped from flowing into the branch flow path and flowed into the solid silica unit whose removal capacity has recovered.

[0034] In one embodiment of the present invention, the substrate processing device further comprises: a circulating flow path for circulating the etching liquid, which is connected in the exhaust flow path at the same position as the measurement position or at a position downstream of the measurement position, and at a position downstream of the solid silica unit and upstream of the measurement position; and a circulating flow path opening and closing unit, which opens and closes the circulating flow path.

[0035] According to this substrate processing apparatus, the etching liquid can be caused to flow into the circulation flow path, or the etching liquid can be stopped from flowing into the circulation flow path and flowed into the return flow path.

[0036] Therefore, for example, if the silicon concentration measured by the concentration measurement unit is below a predetermined threshold, the flow of etching liquid into the return flow path and the circulation flow path is stopped. If the silicon concentration measured by the concentration measurement unit exceeds the threshold, the circulation flow path can be opened and closed so that the etching liquid flows into the circulation flow path for a predetermined period of time, and then the etching liquid in the circulation flow path flows into the return flow path. By opening and closing the circulation flow path in this way, the supply of etching liquid to the solid silica unit can be stopped, and the etching liquid can be circulated in the circulation flow path.

[0037] Therefore, for example, the plurality of solid silicas within the silica storage unit can be cooled while the etching liquid circulates within the circulation flow path, allowing the plurality of solid silicas within the silica storage unit to be replaced with sufficiently cooled solid silicas. After a predetermined period of time, the etching liquid is stopped from flowing into the circulation flow path and is directed to flow into the return flow path. Thus, after the predetermined period of time, the etching liquid can be directed to the solid silica unit, whose removal capacity has been restored.

[0038] In one embodiment of the present invention, the substrate processing apparatus further includes a supply flow path for supplying the etching liquid in the etching liquid tank to the etching processing unit.

[0039] According to this substrate processing apparatus, the etching liquid stored in the etching liquid tank can be supplied to the etching processing unit via the supply flow path. Therefore, the etching liquid with a sufficiently reduced silicon concentration can be reused for processing substrates in the etching processing unit.

[0040] In one embodiment of the present invention, a plurality of solid silica units are provided, and the plurality of solid silica units are arranged in series in the discharge flow path. This reduces the amount of silica removed by each solid silica unit. Consequently, compared to a configuration in which a single solid silica unit is provided in the discharge flow path, the time required for the removal capacity of the solid silica unit to recover can be delayed.

[0041] In another embodiment of the present invention, a plurality of solid silica units are provided, and the plurality of solid silica units are arranged in parallel in the exhaust flow path. Therefore, if at least one of the plurality of solid silica units is placed in a usable state, silicon oxide can be continuously removed from the etching solution. Thus, while silicon oxide can be continuously removed from the etching solution, the removal capacity of the solid silica unit that is not removing silicon oxide can be restored.

[0042] Another embodiment of the present invention provides a substrate processing method comprising: an etching step of etching a substrate with an etching liquid in an etching processing unit; a discharge step of discharging the etching liquid from the etching processing unit; and a solid silica passing step of passing the etching liquid discharged into the discharge flow path in the discharge step through a silica storage unit containing a plurality of solid silicas. This substrate processing method achieves the same effects as the aforementioned substrate processing apparatus.

[0043] In another embodiment of the present invention, the substrate processing method further includes: a concentration measuring step of measuring the silicon concentration in the etching solution after passing through the silicon dioxide receiving portion; and a judgment step of judging whether the silicon concentration measured by the concentration measuring step is below a specified threshold value.

[0044] Furthermore, when it is determined in the judgment step that the silicon concentration measured in the concentration measurement step is below the threshold value, a recovery step is performed in which the etching liquid tank recovers the etching liquid after passing through the silica containing section. When it is determined in the judgment step that the silicon concentration measured in the concentration measurement step is not below the threshold value, a return step is performed in which the etching liquid is returned to the upstream side of the silica containing section in the discharge flow path. Thus, the recovery step or the return step is selectively performed.

[0045] The above and other objects, features and effects of the present invention will become apparent from the following description of the embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a diagram showing the overall structure of a substrate processing apparatus according to a first embodiment of the present invention.

[0047] Figure 2 It is a schematic diagram of a solid silica unit included in the substrate processing apparatus.

[0048] Figure 3A as well as Figure 3B It is a schematic diagram for explaining the shape of the solid silica included in the solid silica unit.

[0049] Figure 4 This is a block diagram showing an example of the electrical configuration of a main portion of the substrate processing apparatus.

[0050] Figure 5 This is a flowchart for explaining an example of the operation of the substrate processing apparatus.

[0051] Figures 6A to 6D It is a schematic diagram for explaining an operation example of the substrate processing apparatus.

[0052] Figure 7 This is a flowchart for explaining another operation example of the substrate processing apparatus.

[0053] Figure 8 It is a schematic diagram for explaining a first modified example of the substrate processing apparatus.

[0054] Figure 9 It is a schematic diagram for explaining a second modified example of the substrate processing apparatus.

[0055] Figure 10 It is a schematic diagram for explaining a substrate processing apparatus according to a second embodiment of the present invention.

[0056] Figure 11 It is a schematic diagram for explaining a substrate processing apparatus according to a third embodiment of the present invention.

[0057] Figure 12 It is a schematic diagram for explaining a substrate processing apparatus according to a fourth embodiment of the present invention.

[0058] Figure 13 It is a schematic diagram for explaining a modified example of the above-mentioned solid silica unit.

[0059] Figure 14 It is a schematic diagram for explaining a modified example of the etching processing unit included in the above-mentioned substrate processing apparatus.

[0060] Figure 15 It is a schematic diagram for explaining the situation near the surface of the substrate during etching. DETAILED DESCRIPTION

[0061] <First embodiment>

[0062] Figure 1 It is a diagram showing the overall structure of a substrate processing apparatus 1 according to the first embodiment of the present invention.

[0063] The substrate processing apparatus 1 etches a substrate W using an etching solution such as an aqueous phosphoric acid solution and also regenerates the etching solution used for the etching process. The etching solution is not limited to an aqueous phosphoric acid solution and may also be a solution containing an additive to the aqueous phosphoric acid solution. The temperature of the etching solution used for the etching process is, for example, approximately 160°C.

[0064] The substrate W processed by the substrate processing apparatus 1 is, for example, a disk-shaped semiconductor wafer. Silicon oxide is formed by performing an etching process on the surface of the substrate W.

[0065] For example, a silicon oxide layer and a silicon nitride layer are exposed on the surface of a substrate W. When such a substrate W is used, the etching solution selectively etches the silicon nitride layer. The silicon oxide formed by etching the silicon nitride layer only slightly dissolves in the etching solution. Substrates W with exposed silicon oxide and silicon nitride layers are used, for example, in the manufacturing process of 3D NAND memory devices.

[0066] The substrate processing apparatus 1 includes an etching unit 2 for etching a substrate W, a discharge pipe 10 for discharging an etching liquid from the etching unit 2, and an etching liquid tank 20 for storing the etching liquid in which the etching liquid flows from the discharge pipe 10. The discharge pipe 10 constitutes a discharge flow path.

[0067] The substrate processing apparatus 1 further includes a supply pipe 30 for supplying an etching liquid to the etching processing section 2, a solid silica unit 40 provided in the discharge pipe 10, and a concentration measuring unit 50 for measuring the concentration of silicon oxide (silicon concentration) in the etching liquid in the discharge pipe 10 on the downstream side of the solid silica unit 40. The substrate processing apparatus 1 further includes a controller 3 (see FIG. 1 ) for controlling the substrate processing apparatus 1. Figure 4 ).

[0068] In this embodiment, the etching unit 2 is an immersion unit that immerses a plurality of (eg, 50) substrates W in an etching solution to perform etching. The etching unit 2 includes an immersion tank 4 that stores the etching solution and performs etching.

[0069] The immersion treatment tank 4 has a double tank structure. Specifically, the immersion treatment tank 4 comprises an inner tank 5 for storing an etching solution so that the substrate W is immersed in the etching solution, an outer tank 6 surrounding at least the upper end of the inner tank 5 and capable of replacing the inner tank 5 and the etching solution, and an elevator 7 for raising and lowering the substrate W relative to the inner tank 5.

[0070] The inner tank 5 is a rectangular container formed of quartz or fluororesin having excellent corrosion resistance to etching liquid. The outer tank 6 is formed of the same material as the inner tank 5 .

[0071] The lifter 7 holds a plurality of substrates W using a plurality of holding rods (not shown). The plurality of substrates W are held by the lifter 7 in a state in which they are arranged parallel to each other in an upright position (a position in which the normal to the main surface of the substrate is in the horizontal direction). The lifter 7 can be raised and lowered in the vertical direction by a lifting mechanism (not shown) having an electric motor or a pneumatic cylinder. The lifter 7 is in a processing position (a batch) where the plurality of substrates W to be held are immersed in the etching solution in the inner tank 5. Figure 1 The position of the etching liquid is raised and lowered between the intersection position with the upper side of the liquid surface of the etching liquid.

[0072] The discharge piping 10 includes an upstream discharge piping 11 on the upstream side of the solid silica unit 40, and a downstream discharge piping 12 on the downstream side of the solid silica unit 40. The upstream end of the discharge piping 10 (the upstream end of the upstream discharge piping 11) is connected to the outer tank 6 of the immersion treatment tank 4. The downstream end of the discharge piping 10 (the downstream end of the downstream discharge piping 12) is connected to the etching liquid tank 20. The downstream end of the discharge piping 10 is located above the liquid level of the etching liquid. The upstream discharge piping 11 constitutes the upstream discharge flow path, and the downstream discharge piping 12 constitutes the downstream discharge flow path.

[0073] While details will be described later, the solid silica unit 40 includes a plurality of solid silicas 41 and a silica container 42 that contains the plurality of solid silicas 41. The solid silica unit 40 cools the etching solution, precipitating silicon oxide from the etching solution, thereby reducing the silicon concentration in the etching solution. Therefore, the solid silica unit 40 discharges the etching solution with a reduced silicon concentration downstream.

[0074] The downstream end of the upstream discharge pipe 11 and the upstream end of the downstream discharge pipe 12 are connected to the silica storage section 42. The etching liquid flows from the upstream discharge pipe 11 into the silica storage section 42 and flows out from the silica storage section 42 to the downstream discharge pipe 12. As the etching liquid passes through the interior space of the silica storage section 42, it is cooled by the plurality of solid silicas 41. As a result, the silicon oxide in the etching liquid precipitates and adheres to the surfaces of the plurality of solid silicas 41.

[0075] The temperature of the plurality of solid silicas 41 is preferably lower than the temperature of the etching solution flowing into the silica containing portion 42 , and is preferably, for example, lower than or equal to room temperature (eg, 25° C.).

[0076] The concentration measurement unit 50 is also called a concentration monitor. It measures the silicon concentration in the etching solution using an electrochemical measurement method, such as an ion selective electrode (ISE). The concentration measurement unit 50, using the ISE method, can accurately measure the silicon concentration in the etching solution, even though measurement would typically take several minutes.

[0077] An example of an electrochemical measurement technique is the one utilizing a fluoride ion selective electrode (FISE). Specifically, hydrofluoric acid (HF) is dripped into a phosphoric acid solution containing dissolved silicon oxide. This generates H₂SiF₂. Based on the change in voltage caused by the amount of fluoride ions consumed, the concentration of silicon oxide in the phosphoric acid solution can be calculated.

[0078] The concentration measurement unit 50 includes a measurement pipe 51 connected to a measurement position 12 a set in the downstream discharge pipe 12 , and a measuring device 52 that takes in the etching liquid through the measurement pipe 51 and measures the silicon concentration in the taken etching liquid.

[0079] Unlike the present embodiment, the concentration measurement unit 50 does not include the measurement piping 51. Instead, the measuring instrument 52 of the concentration measurement unit 50 can be located in the downstream discharge piping 12. In this case, the interior of the measuring instrument 52 constitutes a portion of the discharge flow path, and the internal flow path of the measuring instrument 52 serves as the measurement position 12a. Furthermore, the piping upstream of the concentration measurement unit 50, the piping downstream of the concentration measurement unit 50, and the return piping 60 (described later) are connected to the measuring instrument 52.

[0080] The substrate processing apparatus 1 further includes a return pipe 60 connected to a position (measurement position 12a) in the exhaust pipe 10 where the concentration measurement unit 50 performs measurement, and which returns the etching liquid to the upstream side of the solid silica unit 40 in the exhaust pipe 10; and a return valve 61 provided in the return pipe 60. The return pipe 60 constitutes a return flow path, and the return valve 61 is an example of a return flow path opening and closing unit that opens and closes the return flow path.

[0081] The substrate processing apparatus 1 further includes a branch pipe 70 that branches from a position downstream of a return position 11a connected to the downstream end of the return pipe 60 in the upstream exhaust pipe 11 and upstream of the solid silica unit 40, and is connected to a position downstream of the solid silica unit 40 and upstream of the measurement position 12a; and a branch valve 71 provided on the branch pipe 70. The branch pipe 70 constitutes a branch flow path, and the branch valve 71 is an example of a branch flow path opening and closing unit that opens and closes the branch flow path.

[0082] By returning the etching liquid to a position upstream of the solid silica unit 40 in the upstream discharge pipe 11 via the return pipe 60, the etching liquid that has once passed through the solid silica unit 40 can be passed through the solid silica unit 40 again. By allowing the etching liquid that has returned to the return position 11a to flow into the branch pipe 70, the supply of the etching liquid to the solid silica unit 40 can be stopped while the etching liquid circulates through the return pipe 60, the upstream discharge pipe 11, and the branch pipe 70.

[0083] The substrate processing apparatus 1 further includes an upstream discharge pump 13, a first upstream discharge valve 14, a second upstream discharge valve 15, a downstream discharge pump 16, and a downstream discharge valve 17. The upstream discharge pump 13, the first upstream discharge valve 14, the second upstream discharge valve 15, the downstream discharge pump 16, and the downstream discharge valve 17 are provided in this order on the discharge pipe 10, from the upstream side to the downstream side. Specifically, the upstream discharge pump 13, the first upstream discharge valve 14, and the second upstream discharge valve 15 are provided in the upstream discharge pipe 11, while the downstream discharge pump 16 and the downstream discharge valve 17 are provided in the downstream discharge pipe 12.

[0084] An upstream discharge pump 13 delivers the etching liquid in the outer tank 6 of the immersion treatment tank 4 to the upstream discharge pipe 11 of the discharge pipe 10. A first upstream discharge valve 14 is provided on the upstream discharge pipe 11 upstream of the return position 11a. A second upstream discharge valve 15 is provided on the upstream discharge pipe 11 downstream of the upstream branch position 11b to which the upstream end of the branch pipe 70 is connected.

[0085] The first upstream discharge valve 14 is an example of a first upstream discharge flow path opening and closing means for opening and closing the upstream discharge flow path formed by the upstream discharge pipe 11. The second upstream discharge valve 15 is an example of a second upstream discharge flow path opening and closing means for opening and closing the upstream discharge flow path formed by the upstream discharge pipe 11 on the downstream side of the first upstream discharge valve 14.

[0086] Downstream discharge pump 16 is provided in downstream discharge piping 12, downstream of downstream branching position 12b, to which the downstream end of branch pipe 70 is connected, and upstream of measurement position 12a. Downstream discharge valve 17 is provided in downstream discharge piping 12, downstream of measurement position 12a. Downstream discharge valve 17 is an example of downstream discharge flow path opening and closing means for opening and closing the downstream discharge flow path formed by downstream discharge piping 12.

[0087] The upstream end of the supply pipe 30 is connected to the etching liquid tank 20. The supply pipe 30 extends into the etching liquid tank 20 so that its upstream end is located below the liquid level of the etching liquid. The downstream end of the supply pipe 30 is positioned above the outer tank 6 of the immersion treatment tank 4 so that the etching liquid can be supplied from the supply pipe 30 to the outer tank 6. The substrate processing apparatus 1 further includes a supply pump 31 provided in the supply pipe 30, and a supply valve 32 provided in the supply pipe 30 downstream of the supply pump 31. The supply pump 31 delivers the etching liquid in the etching liquid tank 20 to the supply pipe 30. The supply pipe 30 constitutes a supply flow path, and the supply valve 32 is an example of a supply flow path opening and closing unit that opens and closes the supply flow path.

[0088] Thus, the etching liquid stored in the etching liquid tank 20 can be supplied to the etching processing unit 2 via the supply pipe 30 . Therefore, the etching liquid with a reduced silicon concentration by the solid silica unit 40 can be reused in processing the substrate W in the etching processing unit 2 .

[0089] The substrate processing apparatus 1 further includes a temperature regulating unit 21 for regulating the temperature of the etching liquid in the etching liquid tank 20. The temperature regulating unit 21 is, for example, a heater for heating the etching liquid in the etching liquid tank 20. The temperature regulating unit 21 is, for example, Figure 1 The heater shown is mounted on the side wall and bottom wall of the etching liquid tank 20 from the outside. Figure 1 The temperature control unit 21 can be a heater immersed in the etching liquid in the etching liquid tank 20, or a heater provided with piping that circulates the liquid in the etching liquid tank 20 and heats the piping. The etching liquid in the etching liquid tank 20 is maintained at a high temperature of approximately 160°C by the temperature control unit 21.

[0090] The substrate processing apparatus 1 further includes a waste liquid pipe 80 for discharging the etching liquid in the discharge pipe 10, and a waste liquid valve 81 provided on the waste liquid pipe 80. The waste liquid pipe 80 constitutes a waste liquid flow path. The waste liquid valve 81 is an example of a waste liquid flow path opening and closing unit that opens and closes the waste liquid flow path.

[0091] Waste liquid piping 80 is connected to upstream discharge piping 11 at a position downstream of upstream discharge pump 13 and upstream of first upstream discharge valve 14. Waste liquid piping 80 is used to discard etching liquid when the etching liquid flows from etching treatment unit 2 into upstream discharge piping 11 while the flow of etching liquid into solid silica unit 40 is stopped. The period during which the flow of etching liquid into solid silica unit 40 is stopped refers to, for example, the period during which concentration measurement unit 50 is measuring the silicon concentration in the etching liquid.

[0092] The substrate processing apparatus 1 further includes a fresh liquid pipe 90 for replenishing the etching liquid tank 20 with fresh etching liquid (fresh liquid); a fresh liquid pump 91 provided on the fresh liquid pipe 90; and a fresh liquid valve 92 provided on the fresh liquid pipe 90 downstream of the fresh liquid pump 91. The fresh liquid pipe 90 constitutes a fresh liquid flow path. The fresh liquid valve 92 is an example of a fresh liquid flow path opening and closing unit that opens and closes the fresh liquid flow path.

[0093] The substrate processing apparatus 1 further includes a cooling unit 100 for cooling the plurality of solid silica containers 41. The cooling unit 100 includes a coolant supply pipe 101 for supplying coolant to the interior of the silica container 42, a coolant pump 102 provided in the coolant supply pipe 101, a coolant supply valve 103 provided in the coolant supply pipe 101 downstream of the coolant pump 102, a coolant discharge pipe 104 for discharging the coolant from the interior of the silica container 42, and a coolant discharge valve 105 provided in the coolant discharge pipe 104. The coolant is, for example, deionized water (DIW) at a temperature below room temperature.

[0094] The coolant supply pipe 101 forms a coolant supply flow path, and the coolant supply valve 103 is an example of a coolant supply flow path opening and closing unit that opens and closes the coolant supply flow path. The coolant discharge pipe 104 forms a coolant discharge flow path, and the coolant discharge valve 105 is an example of a coolant discharge flow path opening and closing unit that opens and closes the coolant discharge flow path.

[0095] The plurality of solid silicas 41 can be cooled by passing the cooling liquid through the internal space of the silica container 42 using the cooling unit 100. Therefore, the temperature of the plurality of solid silicas 41, which has been increased by the passage of the etching liquid, can be reduced.

[0096] For example, by cooling the plurality of solid silica units 41 in advance, the etching liquid can be rapidly cooled when passing through the solid silica unit 40. This allows silicon oxide to be rapidly precipitated.

[0097] The substrate processing apparatus 1 may also include an inert gas supply unit 110 for supplying an inert gas such as nitrogen into the interior of the silica container 42. The inert gas supply unit 110 includes an inert gas pipe 111 connected to the silica container 42 and an inert gas valve 112 for opening and closing the inert gas pipe 111.

[0098] The inert gas pipe 111 constitutes an inert gas supply flow path, and the inert gas valve 112 is an example of an inert gas supply flow path opening and closing unit that opens and closes the inert gas supply flow path.

[0099] The inert gas supplied from the inert gas supply unit 110 can be used to push out any coolant remaining within the silica storage unit 42. This prevents the etching liquid from mixing with the coolant, which would otherwise reduce the concentration of the etchant in the etching liquid, when the etching liquid passes through the interior space of the silica storage unit 42 after the coolant has cooled the plurality of solid silica particles. The coolant discharge pipe 104 also functions as an inert gas discharge flow path, and the coolant discharge valve 105 also functions as an inert gas discharge flow path opening and closing unit that opens and closes the inert gas discharge flow path.

[0100] Figure 2 is a schematic diagram of a solid silica unit 40 .

[0101] Reference Figure 2 The silica container 42 of the solid silica unit 40 is, for example, cylindrical. The silica container 42 includes a cylindrical space 43 (internal space) filled with a plurality of solid silicas 41. The downstream end of the upstream discharge pipe 11 is connected to one end of the cylindrical space 43 in the axial direction X along the central axis A1, and the upstream end of the downstream discharge pipe 12 is connected to the other end of the cylindrical space 43 in the axial direction X.

[0102] Solid silicon dioxide 41 is in the form of particles, such as Figure 2 As shown, for example, it is a spherical shape. The spherical shape is also called a bead shape. The etching liquid EL flowing from the upstream discharge pipe 11 into the cylindrical space 43 is as shown in FIG. Figure 2 As shown in the enlarged view, the etching liquid EL flows from one end of the cylindrical space 43 toward the other end through the gap G between adjacent solid silica particles 41. Therefore, the etching liquid EL contacts the multiple solid silica particles 41 as it passes through the silica container 42, effectively cooling the etching liquid EL. Cooling the etching liquid EL reduces the saturation concentration of silicon oxide in the etching liquid EL. Consequently, silicon oxide dissolved in the etching liquid EL precipitates and adheres to the surfaces of the multiple solid silica particles 41. This allows for rapid precipitation of silicon oxide from the etching liquid EL, effectively reducing the silicon concentration in the etching liquid EL.

[0103] The etching liquid EL contacts the solid silicon dioxide 41 and is locally cooled, causing silicon oxide to precipitate. Therefore, compared to a configuration in which the etching liquid EL is stored in a bath and then cooled to cool the entire etching liquid EL, the amount of etching liquid EL that can be cooled at one time can be reduced, thereby enabling silicon oxide to be precipitated more quickly from the etching liquid EL.

[0104] Furthermore, the contact area between the etching liquid EL and the plurality of solid silicas 41 is larger than that in a configuration where the bath storing the etching liquid EL is cooled. Specifically, since a plurality of solid silicas 41 are provided, the surface area of ​​the plurality of solid silicas 41 as a whole tends to be larger than the surface area of ​​the side walls and bottom wall of the bath. Therefore, the use of a plurality of solid silicas 41 allows for efficient cooling of the etching liquid EL.

[0105] Furthermore, compared to the present embodiment, in a configuration in which the etching liquid EL and the precipitated silicon oxide are passed through a filter to remove silicon oxide from the etching liquid EL, the filter is more likely to become clogged. On the other hand, in the solid silicon dioxide unit 40, a sufficiently large gap G is formed between adjacent solid silicon dioxide units 41. Therefore, when silicon oxide precipitates on the surface of the solid silicon dioxide units 41, clogging of the gap G between adjacent solid silicon dioxide units 41 can be suppressed.

[0106] The particle size R of the solid silica 41 is, for example, not less than 1 mm and not more than 10 mm. When the particle size R of the solid silica 41 is within this range, it is easy to form a gap G of an appropriate size between adjacent solid silicas 41. When silicon oxide precipitates on the surface of the solid silica 41, it is possible to further suppress the clogging of the gap G between adjacent solid silicas 41. When the solid silica 41 is assumed to be an ideal sphere, the particle size R of the solid silica 41 is a convenient value equivalent to its diameter. When the solid silica 41 is spherical, the particle size R of the solid silica 41 is the diameter of the sphere.

[0107] As described above, by using the solid silica unit 40 , the silicon concentration in the etching solution EL can be reduced satisfactorily.

[0108] Furthermore, the etching liquid EL can be cooled simply by passing it through the silica container 42. That is, the etching liquid EL can be cooled without providing a device for cooling the etching liquid EL outside the solid silica unit 40. Therefore, an increase in the size of the solid silica unit 40 can be suppressed.

[0109] Furthermore, as described above, the etching liquid EL flows from one end to the other end in the axial direction X within the cylindrical space 43. Therefore, the linear velocity uniformity of the etching liquid EL can be improved at each position in the axial direction X of the cylindrical space 43. Consequently, silicon oxide is easily precipitated throughout the plurality of solid silicon dioxide particles 41 within the cylindrical space 43.

[0110] The shape of the solid silica 41 is not limited to a spherical shape, and may be any particle having a certain size. The shape of the solid silica 41 may be, for example, an ellipsoidal shape, a polyhedron shape (see Figure 3A) or tablet shape (see Figure 3B )wait.

[0111] If the solid silica 41 is in a polyhedral or tablet shape, each solid silica 41 has corners 41a. In the case of a polyhedral shape, corners 41a are formed by vertices and edges. In the case of a tablet shape, the solid silica 41 has a cylindrical surface 41b and a pair of spherical surfaces 41c provided at both ends of the cylindrical surface 41b in the axial direction. In the case of a tablet shape, corners 41a are the intersections of the cylindrical surface 41b and the spherical surfaces 41c.

[0112] When the solid silica 41 has a tablet shape or a polyhedron shape, the particle size R of the solid silica 41 is the average value of a straight line passing through the center of gravity of the solid silica 41 inside the solid silica 41 .

[0113] The inventors of the present application have discovered that when using solid silicon dioxide 41 having granular shapes with corners 41 a, liquid exchange of the etching solution EL is more likely to occur around the corners 41 a. As a result, silicon oxide is more likely to precipitate at the corners 41 a and the surrounding areas on the surface of the solid silicon dioxide 41. Therefore, by using solid silicon dioxide 41 having granular shapes with corners 41 a, silicon oxide dissolved in the etching solution EL can be effectively precipitated.

[0114] The shape of the solid silicon dioxide 41 having the corners 41a is not limited to a polyhedron or a tablet shape. Figure 3B The polyhedron shown is a regular hexahedron, but is not limited to a regular hexahedron. For example, it may be a regular octahedron or a regular dodecahedron. Furthermore, the polyhedron is not limited to a regular polyhedron, as long as it has corners 41a.

[0115] The controller 3 includes a microcomputer and controls the control objects of the substrate processing apparatus 1 according to a predetermined program. More specifically, the controller 3 includes a processor (CPU) 3a and a memory 3b storing a program. The processor 3a executes the program to perform various control processes for substrate processing.

[0116] In particular, the controller 3 controls the operation of the etching process section 2, the temperature adjustment unit 21, the concentration measurement unit 50, the upstream discharge pump 13, the downstream discharge pump 16, the supply pump 31, the new liquid pump 91, the coolant pump 102, the first upstream discharge valve 14, the second upstream discharge valve 15, the downstream discharge valve 17, the supply valve 32, the return valve 61, the branch valve 71, the waste liquid valve 81, the new liquid valve 92, the coolant supply valve 103, the coolant discharge valve 105, the inert gas valve 112, etc. In addition, the controller 3 also controls the operation of components included in the substrate processing apparatus 1 according to each modified example described below, and the substrate processing apparatuses 1P, 1Q, and 1R according to each embodiment.

[0117] Figure 5 This is a flowchart for explaining an operation example of the substrate processing apparatus 1 . Figures 6A to 6D Schematic diagram for explaining an example of the operation of the substrate processing apparatus 1. Figures 6A to 6D In FIG, open valves are shown in black and closed valves are shown in white.

[0118] The substrate W is immersed in the etching liquid contained in the immersion treatment tank 4 of the etching treatment unit 2. Thus, etching treatment (etching process) is performed on the substrate W. Figure 6A As shown, for example, etching liquid is supplied from the supply pipe 30 to the etching treatment unit 2 (supply process). During the supply process, in order to adjust the liquid volume in the immersion treatment tank 4, the etching liquid is discharged from the etching treatment unit 2 to the upstream discharge pipe 11 (discharge process). In the discharge process, the etching liquid discharged to the upstream discharge pipe 11 passes through the solid silica unit 40. Specifically, it passes through the silica storage unit 42 that stores a plurality of solid silicas (solid silica passing process). More specifically, the etching liquid flows into the internal space of the silica storage unit 42 of the solid silica unit 40 and flows out from the internal space to the downstream discharge pipe 12. The etching liquid is cooled by the plurality of solid silicas 41 while passing through the solid silica unit 40 (etching liquid cooling process).

[0119] The etching liquid passing through the solid silica unit 40 reaches the measurement position 12a. Before the etching liquid reaches the measurement position 12a, the downstream discharge valve 17 is closed. Then, the first upstream discharge valve 14 is closed and the return valve 61 is opened ( Figure 5 Step S1). Thus, the etching liquid that has reached the measurement position 12a is returned to the upstream discharge pipe 11 via the return pipe 60 (return process). The silicon concentration in the etching liquid that has reached the measurement position 12a is measured by the concentration measuring unit 50 ( Figure 5 Step S2: Concentration measurement step. Specifically, a portion of the etching liquid that has reached the measurement position 12a is supplied to the measuring device 52 via the measurement pipe 51, and the measuring device 52 starts measuring the silicon concentration in the etching liquid.

[0120] Then, the controller 3 monitors whether the measurement of the silicon concentration in the etching solution is completed ( Figure 5 Step S3: Measurement time monitoring process). Therefore, during the period until the prescribed measurement time has passed ( Figure 5 Step S3: No), the etching liquid is returned to the upstream discharge pipe 11 via the return pipe 60. Figure 6B As shown, the silica circulates through the upstream discharge pipe 11, the solid silica unit 40, the downstream discharge pipe 12, and the return pipe 60 (first circulation step).

[0121] After the specified measurement time ( Figure 5 Step S3: Yes), the controller 3 determines whether the silicon concentration (measured concentration) measured by the concentration measuring unit 50 is below a predetermined threshold value ( Figure 5 Step S4: judgment process).

[0122] When the controller 3 determines that the measured concentration is below the threshold value ( Figure 5 Step S4: Yes), close the return valve 61, and instead open the downstream discharge valve 17 ( Figure 5 Step S5). Thus, Figure 6C As shown, the circulation of the etching liquid is stopped, and the etching liquid is supplied to the etching liquid tank 20 via the downstream discharge pipe 12. That is, the etching liquid with a sufficiently reduced silicon concentration is recovered (recovery step).

[0123] When the controller 3 determines that the measured concentration exceeds the threshold value ( Figure 5 Step S4: No), close the second upstream discharge valve 15, and instead open the branch valve 71 ( Figure 5 Step S6). Thus, as Figure 6D As shown, the supply of the etching liquid to the solid silica unit 40 is stopped, and the etching liquid circulates in the return pipe 60, the upstream discharge pipe 11, and the branch pipe 70 (second circulation step).

[0124] In this manner, when the controller 3 determines that the measured concentration exceeds the threshold value, the return step is also executed. Therefore, the recovery step and the second circulation step (return step) are selectively executed based on the determination result of the determination step.

[0125] The controller 3 monitors whether a predetermined recovery time ( Figure 5 Step S7: Resume time monitoring process).

[0126] During the period until the recovery time has passed ( Figure 5(Step S7: No), the plurality of solid silicas 41 in the solid silica unit 40 are cooled using the cooling unit 100 (solid silica cooling step). Specifically, the coolant supply valve 103 and the coolant discharge valve 105 are opened. This allows coolant to be supplied to the interior of the silica storage section 42 of the solid silica unit 40 (coolant supply step). The coolant supplied to the interior of the silica storage section 42 passes through the silica storage section 42 and is discharged from the coolant discharge pipe 104 (coolant discharge step). The plurality of solid silicas 41 are cooled by the coolant, thereby restoring the removal capacity of the solid silica unit 40.

[0127] Unlike the present embodiment, before the recovery time has elapsed, the plurality of solid silicas 41 in the silica container 42 may be replaced with new solid silicas 41 , or the entire solid silica unit 40 may be replaced with a new solid silica unit 40 .

[0128] If the recovery time ( Figure 5 Step S7: Yes), then open the second upstream discharge valve 15, and instead close the branch valve 71 ( Figure 5 Step S8). Thus, Figure 6B As shown, the etching liquid is supplied to the solid silica unit 40 again, and the etching liquid is cooled again based on the plurality of solid silicas 41 (etching liquid re-cooling step).

[0129] The etching liquid that has passed through the solid silicon dioxide unit 40 again reaches the measurement position 12a. Thereafter, the process returns to step S2 and the concentration measurement unit 50 is used to start measuring the silicon concentration in the etching liquid again. When the etching liquid is cooled again and the measured concentration becomes less than the predetermined threshold value ( Figure 5 Step S4: Yes), close the return valve 61, and instead open the downstream discharge valve 17 ( Figure 5 Step S5). Thus, Figure 6C As shown, the circulation of the etching liquid is stopped, and the etching liquid is supplied to the etching liquid tank 20 through the downstream discharge pipe 12. That is, the etching liquid with a sufficiently reduced silicon concentration is recovered (recovery step).

[0130] According to the first embodiment, the silicon concentration in the etching solution can be reduced satisfactorily by the solid silica unit 40 .

[0131] According to the first embodiment, the downstream discharge valve 17 allows the etching liquid to flow into the etching liquid tank 20 when the measured concentration is below a predetermined threshold value, and stops the flow of etching liquid into the etching liquid tank 20 when the measured concentration exceeds the threshold value. Therefore, when the removal capability of the plurality of solid silicas 41 is sufficiently high, the etching liquid is supplied to the etching liquid tank 20. On the other hand, when the removal capability of the plurality of solid silicas 41 decreases and the silicon concentration of the etching liquid after passing through the solid silica unit 40 exceeds the threshold value, the supply of etching liquid to the etching liquid tank 20 is stopped. Therefore, etching liquid with a sufficiently reduced silicon concentration can be selectively recovered by the etching liquid tank 20.

[0132] According to the first embodiment, the return valve 61 is configured to stop the flow of the etching liquid into the return pipe 60 if the measured concentration is below a threshold value, and to allow the etching liquid to flow into the return pipe 60 if the measured concentration exceeds the threshold value. Furthermore, the branch valve 71 is configured to allow the etching liquid, which has returned to the return position 11a via the return pipe 60, to flow into the branch pipe 70 during a predetermined recovery time if the measured concentration exceeds the threshold value.

[0133] Therefore, if the measured concentration exceeds the threshold, the etching liquid returned to the return position 11a via the return pipe 60 flows into the branch pipe 70 within the predetermined recovery time. Therefore, the flow of the etching liquid into the solid silica unit 40 is stopped. Therefore, the supply of the etching liquid to the solid silica unit 40 can be stopped, and the etching liquid can be circulated in the branch pipe 70 and the return pipe 60.

[0134] According to the first embodiment, the coolant supply valve 103 allows the coolant to flow into the coolant supply pipe 101 during the recovery time. Therefore, while the etching solution is stopped from flowing into the solid silica unit 40, the plurality of solid silicas 41 can be cooled by supplying the coolant to the silica container 42. Therefore, compared to cooling the plurality of solid silicas 41 from the outside of the silica container 42, the solid silicas 41 located relatively inside can be cooled more quickly.

[0135] Figure 7 This is a flowchart for explaining another operation example of the substrate processing apparatus 1 . Figure 7 The example of the operation shown is the same as Figure 5 The difference of the operation example shown is that in step S4, when the controller 3 determines that the measured concentration exceeds the predetermined threshold value ( Figure 7 In step S4: No), instead of opening the branch valve 71, the second upstream exhaust valve 15 is still opened and the concentration measuring unit 50 is used to start measuring the silicon concentration in the etching solution again ( Figure 7 Thus, during the measurement time of step S3, as shown in FIG. Figure 6BAs shown, the etching liquid returned to the upstream discharge pipe 11 via the return pipe 60 passes through the silica storage portion 42 of the solid silica unit 40 again, so that the etching liquid is further precipitated from the silicon oxide, thereby reducing the silicon concentration in the etching liquid.

[0136] After step S10, the controller 3 monitors whether the measurement of the silicon concentration in the etching solution is completed ( Figure 7 Step S11: Measurement time monitoring process). Therefore, during the period until the prescribed measurement time has passed ( Figure 7 Step S11: No), the etching liquid is returned to the upstream discharge pipe 11 via the return pipe 60. Figure 6B As shown, a circulation of the upstream discharge pipe 11, the solid silica unit 40, the downstream discharge pipe 12, and the return pipe 60 is continuously performed.

[0137] After the specified measurement time ( Figure 7 Step S11: Yes), the controller 3 determines whether the measured concentration is below a predetermined threshold value ( Figure 7 Step S12: judgment process).

[0138] When the controller 3 determines that the measured concentration is below the threshold value ( Figure 7 Step S12: Yes), close the return valve 61, and instead open the downstream discharge valve 17 ( Figure 7 Step S5). When the controller 3 determines that the measured concentration exceeds the threshold value ( Figure 7 Step S12: No), and Figure 5 Similarly to the illustrated operation example, after executing steps S6 to S8 , the process returns to step S2 .

[0139] Hereinafter, modifications (a first modification and a second modification) of the substrate processing apparatus 1 according to the first embodiment will be described.

[0140] Figure 8 1 is a schematic diagram for explaining a first modification of the substrate processing apparatus 1. Figure 8 As shown, the downstream end of the supply pipe 30 may be connected to the lower end of the inner tank 5 of the immersion treatment tank 4 .

[0141] Figure 9 1 is a schematic diagram for explaining a second modified example of the substrate processing apparatus 1. Figure 9As shown, a dissolving liquid supply unit 150 may also be provided, which supplies a dissolving liquid such as fluoric acid (hydrofluoric acid) to the plurality of solid silicas 41 to dissolve and remove the silicon oxide attached to the surfaces of the plurality of solid silicas 41 due to precipitation. The dissolving liquid supply unit 150 includes, for example, a dissolving liquid supply pipe 151 for supplying the dissolving liquid to the silica storage portion 42, and a dissolving liquid supply valve 152 provided on the dissolving liquid supply pipe 151. The downstream end of the dissolving liquid supply pipe 151 may be branched and connected to the cooling liquid supply pipe 101. The dissolving liquid supply pipe 151 constitutes a dissolving liquid supply flow path, and the dissolving liquid supply valve 152 is an example of a dissolving liquid supply flow path opening and closing unit that opens and closes the dissolving liquid supply flow path.

[0142] The cooling liquid discharge pipe 104 also functions as a solution discharge pipe for discharging the solution from the silica storage portion 42. The solution supply unit 150 may include a pump (not shown) for delivering the solution to the solution supply pipe 151.

[0143] For example, after silicon oxide is removed from the surfaces of the plurality of solid silicas 41 using the dissolving liquid, the dissolving liquid may be replaced with the cooling liquid from the silica container 42 , and the plurality of solid silicas 41 may be cooled using the cooling liquid.

[0144] <Second embodiment>

[0145] Next, the configuration and operation of the substrate processing apparatus 1P according to the second embodiment will be described. Figure 10 Schematic diagram for explaining the substrate processing apparatus 1P. Figure 10 In relation to the aforementioned Figures 1 to 9 The same structure as shown is marked with Figure 1 The same reference numerals are used and their descriptions are omitted.

[0146] The substrate processing apparatus 1P of the second embodiment differs primarily from the substrate processing apparatus 1 of the first embodiment in that, in place of the branch pipe 70, a circulation pipe 120 is provided for circulating the etching liquid within the downstream discharge pipe 12. The circulation pipe 120 is connected to a measurement position 12a of the downstream discharge pipe 12 and an upstream position 12c located downstream of the solid silica unit 40 and upstream of the measurement position 12a and the downstream discharge pump 16 in the downstream discharge pipe 12. A circulation valve 121 is provided on the circulation pipe 120. The circulation pipe 120 constitutes a circulation flow path, and the circulation valve 121 is an example of a circulation flow path opening and closing unit that opens and closes the circulation flow path.

[0147] When the substrate processing apparatus 1P is used, it is possible to allow the etching liquid to flow into the circulation pipe 120, or to stop the flow of the etching liquid into the circulation pipe 120 and allow it to flow into the return pipe 60. Therefore, for example, the following operation can be performed. If the measured concentration is below a predetermined threshold value, the circulation flow path is closed to stop the flow of the etching liquid into the return pipe 60 and the circulation pipe 120. Furthermore, if the measured concentration exceeds the threshold value, the circulation flow path is opened to allow the etching liquid in the circulation pipe 120 to flow into the return pipe 60 after the etching liquid flows into the circulation pipe 120 for a predetermined recovery time. By opening and closing the circulation flow path in this manner, it is possible to stop the supply of etching liquid to the solid silica unit 40 and circulate the etching liquid in the circulation pipe 120.

[0148] Therefore, for example, the plurality of solid silicas 41 in the silica storage section 42 can be cooled, or the plurality of solid silicas 41 in the silica storage section 42 can be replaced with sufficiently cooled solid silicas 41. After the recovery time has elapsed, the etching liquid in the circulation pipe 120 flows into the return pipe 60. Therefore, after the recovery time has elapsed, the etching liquid can flow into the solid silica unit 40, whose removal capacity has been restored. Thus, silicon oxide can be removed from the etching liquid.

[0149] <Third embodiment>

[0150] Next, the configuration and operation of a substrate processing apparatus 1Q according to the third embodiment will be described. Figure 11 Schematic diagram for explaining the substrate processing apparatus 1Q. Figure 11 In FIG, only the solid silica unit 40 and its surroundings in the substrate processing apparatus 1Q are shown. Figure 11 In relation to the aforementioned Figures 1 to 10 The same structure as shown is marked with Figure 1 The same reference numerals are used and their descriptions are omitted.

[0151] The substrate processing apparatus 1Q is mainly different from the substrate processing apparatus 1 of the first embodiment in that two solid silica units 40 are arranged in series in the exhaust pipe 10 .

[0152] The two solid silica units 40 have the same structure. A cooling unit 100 is provided in each solid silica unit 40. Although not shown in the figure, an inert gas supply unit 110 (see Figure 1 ).

[0153] The discharge piping 10 includes an upstream discharge piping 11 located upstream of the plurality of solid silica units 40, a downstream discharge piping 12 located downstream of the plurality of solid silica units 40, and an intermediate discharge piping 18 connecting the solid silica units 40. The solid silica unit 40 having a silica storage portion 42 connected to the downstream end of the upstream discharge piping 11 is referred to as a first solid silica unit 40A, and the solid silica unit 40 having a silica storage portion 42 connected to the upstream end of the downstream discharge piping 12 is referred to as a second solid silica unit 40B.

[0154] The upstream end of the intermediate discharge pipe 18 is connected to the silica storage section 42 of the first solid silica unit 40A, and the downstream end of the intermediate discharge pipe 18 is connected to the silica storage section 42 of the second solid silica unit 40B.

[0155] If two solid silica units 40 are arranged in series, the amount of silica removed by a single solid silica unit 40 can be reduced. Therefore, compared to a configuration in which a single solid silica unit 40 is provided in the discharge pipe 10, the time to restore the removal capacity of the solid silica unit 40 can be delayed.

[0156] Unlike the third embodiment, three or more solid silica units 40 may be arranged in series.

[0157] <Fourth embodiment>

[0158] Next, the configuration and operation of a substrate processing apparatus 1Q according to the fourth embodiment will be described. Figure 12 Schematic diagram for explaining the substrate processing apparatus 1R. Figure 12 In FIG, only the solid silica unit 40 and its surroundings in the substrate processing apparatus 1R are shown. Figure 12 In relation to the aforementioned Figures 1 to 11 The same structure as shown is marked with Figure 1 The same reference numerals are used and their descriptions are omitted.

[0159] The substrate processing apparatus 1R is mainly different from the substrate processing apparatus 1 of the first embodiment in that two solid silica units 40 are arranged side by side in the exhaust pipe 10 .

[0160] The two solid silica units 40 have the same structure. A cooling unit 100 is provided in each solid silica unit 40. Although not shown in the figure, an inert gas supply unit 110 (see Figure 1 ).

[0161] The exhaust piping 10 includes an upstream exhaust piping 11 located upstream of one solid silica unit 40 (first solid silica unit 40A), a downstream exhaust piping 12 located downstream of the first solid silica unit 40A, and a branch exhaust piping 19 that branches and connects to the upstream exhaust piping 11 and the downstream exhaust piping 12 and is provided with the other solid silica unit 40 (second solid silica unit 40B). The substrate processing apparatus 1R further includes a branch exhaust valve 19v located upstream of the second solid silica unit 40B in the branch exhaust piping 19. The branch exhaust piping 19 constitutes a branch exhaust flow path, and the branch exhaust valve 19v is an example of a branch exhaust flow path opening and closing unit that opens and closes the branch exhaust flow path.

[0162] The upstream branch connection position 19a, at which the branch discharge pipe 19 branches off from the upstream discharge pipe 11 and is connected, is located downstream of the upstream branch position 11b of the branch pipe 70. The downstream branch connection position 19b, at which the branch discharge pipe 19 branches off from the downstream discharge pipe 12 and is connected, is located upstream of the downstream branch position 12b of the branch pipe 70.

[0163] If two solid silica units 40 are arranged in parallel, silicon oxide can be continuously removed from the etching solution as long as at least one of the two solid silica units 40 has sufficient removal capability. Figure 12 In the example shown, the first solid silica unit 40A is in a usable state. Therefore, the removal capability of the second solid silica unit 40B can be restored while the first solid silica unit 40A continues to remove silicon oxide from the etching solution. Figure 12 , a state is shown in which the removal capability of the second solid silica unit 40B is restored by cooling the plurality of solid silicas 41 by the cooling unit 100 .

[0164] Unlike the fourth embodiment, three or more solid silica units 40 may be arranged in parallel. Furthermore, the third and fourth embodiments may be combined. Specifically, multiple solid silica unit groups formed by directly arranging multiple solid silica units 40 may be provided, and multiple solid silica unit groups may be arranged in parallel.

[0165] <Other Implementation Methods>

[0166] The present invention is not limited to the above-described embodiment, but can be implemented in other forms.

[0167] For example, Figure 13As shown, the silica container 42 of the solid silica unit 40 may also be a liquid reservoir 44 that contains a plurality of solid silicas 41 and stores the etching solution. The solid silica unit 40 may also include a storage filter 45 that stores the plurality of solid silicas 41 and allows the etching solution to pass through. The storage filter 45 preferably has a plurality of holes of a size that prevents the solid silicas 41 from passing through (for example, a size of 1 mm or less in diameter).

[0168] like Figure 13 As shown, if the silica storage portion 42 is a liquid reservoir 44 , the etching liquid discharged from the etching processing unit 2 to the upstream discharge pipe 11 can be stored in the liquid reservoir 44 , and silicon oxide can be precipitated from the etching liquid using the plurality of solid silicas 41 .

[0169] In addition, if Figure 14 As shown, the etching processing unit 2 may also be a leaf-type processing unit that sprays etching liquid toward the substrates W and etches the substrates W one by one. In this case, the etching processing unit 2 includes a spin chuck 130 that rotates the substrate W around a vertical axis A2 passing through the center of the substrate W while holding the substrate W horizontally, an etching liquid nozzle 131 that sprays etching liquid toward the upper surface of the substrate W held by the spin chuck 130, and a processing cup 132 that receives etching liquid splashed from the substrate W. Although not shown, the etching processing unit 2 may also be provided with a rinse liquid nozzle that sprays rinse liquid toward the upper surface of the substrate W to rinse the etching liquid from the upper surface of the substrate W.

[0170] The downstream end of the supply pipe 30 is connected to the etching liquid nozzle 131 , and the upstream end of the discharge pipe 11 upstream of the discharge pipe 10 is connected to the lower end of the processing cup 132 .

[0171] Even when the etching processing section 2 is a leaf-type processing section, the same effects as when the etching processing section 2 is an immersion processing section are achieved except for the following points.

[0172] The replacement efficiency of the etching liquid near the surface of the substrate W differs depending on whether the etching processing unit 2 is a leaf-type processing unit or an immersion processing unit. Figure 15 It is a schematic diagram for explaining the situation near the surface of the substrate W during etching processing.

[0173] When the etching processing unit 2 is a leaf-type processing unit, the flow rate of the etching liquid supplied to the upper surface (upper main surface) of the substrate W is relatively high. Therefore, it is relatively easy to replace the etching liquid in the concave portions 201 of the concave-convex pattern 200 formed on the upper surface of the substrate W with new etching liquid supplied to the upper surface of the substrate W. The concave portions 201 can be gaps between structures 202 or holes formed in the structures 202.

[0174] The concave-convex pattern 200 is formed, for example, using a silicon oxide layer 203 and a silicon nitride layer 204. Specifically, the silicon nitride layer 204 is formed within a plurality of grooves 205 formed in the silicon oxide layer 203. An etching process is sometimes performed to etch the silicon nitride layer 204 within the grooves 205. When an etching process is performed on the substrate W using a paddle-type processing unit, the etching solution in the grooves 205 can be quickly replaced with a new one, thereby rapidly etching the silicon nitride layer 204.

[0175] On the other hand, when the etching unit 2 is an immersion unit, the flow rate of the etching liquid around the substrate W is relatively slow. Therefore, the etching liquid within the recesses 201 of the concave-convex pattern 200 formed on the upper surface of the substrate W is not easily exchanged with the etching liquid outside the recesses 201. Consequently, etching the silicon nitride layer 204 requires a longer time (e.g., three hours) than in a paddle-type unit. Consequently, the amount of etching liquid consumed is also greater than in a paddle-type unit.

[0176] Therefore, when the etching processing unit 2 is an immersion processing unit, as in the above-mentioned embodiment, silicon oxide can be effectively removed from the etching liquid, and the consumption of the etching liquid can be significantly reduced by reusing the etching liquid.

[0177] Unlike the above-described embodiment, a configuration may be employed in which the concentration measuring unit 50 is not provided. In this case, the degree of deterioration of the removal capability of the solid silica unit 40 may also be determined based on the operating time of the solid silica unit 40. Specifically, the degree of deterioration of the removal capability of the solid silica unit 40 may be determined based on the time that has elapsed since the last cooling operation by the cooling unit 100. In the case where multiple solid silicas 41 have not been cooled by the cooling unit 100 at all, the degree of deterioration of the removal capability of the solid silica unit 40 may also be determined based on the time that has elapsed since the multiple solid silicas 41 were used.

[0178] Furthermore, if the measurement time by the concentration measurement unit 50 is extremely short and the controller 3 immediately determines whether the measured concentration of the etching liquid arriving at the measurement position 12 a is below the threshold, there is no need to flow the etching liquid into the return pipe 60 until the measurement time has elapsed. In this case, if the measured concentration of the etching liquid arriving at the measurement position 12 a is below the threshold, the etching liquid does not flow into the return pipe 60 but is sent to the etching liquid tank 20.

[0179] Furthermore, the concentration measurement unit 50 may be, for example, an ICP emission spectrometer (ICP-AES: Inductively Coupled Plasma Atomic Emission Spectroscopy). When the concentration measurement unit 50 is, for example, an ICP emission spectrometer, the ICP emission spectrometer is typically not located in the exhaust pipe 10 but is located separately from the substrate processing apparatus 1. In this case, the etching liquid in the exhaust pipe 10 is sampled, and the silicon concentration in the etching liquid is measured using the ICP emission spectrometer located separately from the substrate processing apparatus 1. However, a configuration in which the ICP emission spectrometer is located in the exhaust pipe 10 is also possible.

[0180] In addition, the upstream end of the return piping 60 and the upstream end of the circulation piping 120 do not need to be connected to the measurement position 12a, and can also be connected to a position downstream of the measurement position 12a and upstream of the downstream discharge valve 17 in the downstream discharge piping 12.

[0181] Figure 8 as well as Figure 9 The modifications shown are also applicable to the second to fourth embodiments.

[0182] The embodiments of the present invention have been described in detail above, but these embodiments are merely specific examples used to clarify the technical content of the present invention. The present invention is not limited to these specific examples, and the scope of the present invention is defined by the appended claims.

Claims

1. A substrate processing device, characterized in that: have: an etching processing unit for etching the substrate using an etching solution; a discharge channel for discharging etching liquid from the etching treatment unit; and A solid silica unit provided in the discharge flow path, The solid silica unit comprises: multiple solid silicas; a silica container that contains a plurality of the solid silicas and allows etching liquid to pass therethrough; and It also includes a cooling unit for cooling the plurality of solid silicas. The cooling unit cools the solid silicon dioxide so that the temperature of the solid silicon dioxide becomes lower than the temperature of the etching liquid flowing into the silicon dioxide storage portion.

2. The substrate processing apparatus according to claim 1, wherein: The solid silica is in the form of particles having corners.

3. The substrate processing apparatus according to claim 1, wherein: The solid silicon dioxide is in the shape of a sphere.

4. The substrate processing apparatus according to claim 2, wherein: The solid silicon dioxide is in the shape of a polyhedron or a tablet.

5. The substrate processing apparatus according to any one of claims 2 to 4, wherein: The particle size of the solid silica is 1 mm or more and 10 mm or less.

6. The substrate processing apparatus according to any one of claims 1 to 4, wherein: The silica container has a cylindrical space filled with a plurality of the solid silicas. The discharge flow path includes an upstream discharge flow path connected to one end of the cylindrical space in the axial direction of the cylindrical space, and a downstream discharge flow path connected to the other end of the cylindrical space in the axial direction.

7. The substrate processing apparatus according to any one of claims 1 to 4, wherein: The silicon dioxide storage portion includes a liquid storage portion that stores a plurality of solid silicon dioxides and stores an etching solution.

8. The substrate processing apparatus according to any one of claims 1 to 4, wherein: The cooling unit includes a cooling liquid supply passage for supplying cooling liquid to the silica storage portion and a cooling liquid discharge passage for discharging cooling liquid from the silica storage portion.

9. The substrate processing apparatus according to any one of claims 1 to 4, wherein: Also features: a concentration measuring unit configured to detect a silicon concentration in the etching liquid at a predetermined measurement position downstream of the solid silica unit in the discharge flow path; an etching liquid tank for storing etching liquid; as well as The discharge flow path opening and closing unit is provided on a downstream side of the measurement position in the discharge flow path and opens and closes the discharge flow path.

10. The substrate processing apparatus according to claim 9, wherein: Also features: a return flow path connected to the discharge flow path at the same position as the measurement position or at a position downstream of the measurement position, and returning the etching liquid to the upstream side of the solid silica unit in the discharge flow path; as well as The return flow path opening and closing unit opens and closes the return flow path.

11. The substrate processing apparatus according to claim 10, wherein: Also features: a branch flow path that branches from a position in the discharge flow path that is downstream of a return position of the etching liquid from the return flow path and upstream of the solid silica unit, and is connected to a position that is downstream of the solid silica unit and upstream of the measurement position; as well as The branch flow path opening and closing unit opens and closes the branch flow path.

12. The substrate processing apparatus according to claim 10, wherein: Also features: a circulation flow path for circulating the etching liquid, connected in the discharge flow path to a position at the same position as the measurement position or a position downstream of the measurement position, and a position downstream of the solid silica unit and upstream of the measurement position; as well as A circulation flow path opening and closing unit opens and closes the circulation flow path.

13. The substrate processing apparatus according to claim 9, wherein: The etching liquid tank further includes a supply flow path for supplying the etching liquid in the etching liquid tank to the etching processing unit.

14. The substrate processing apparatus according to any one of claims 1 to 4, wherein: The solid silicon dioxide unit is provided with a plurality of A plurality of the solid silica units are arranged in series in the discharge flow path.

15. The substrate processing apparatus according to any one of claims 1 to 4, wherein: The solid silicon dioxide unit is provided with a plurality of A plurality of the solid silica units are arranged in parallel in the discharge flow path.

16. A substrate processing method, characterized in that: include: an etching step of etching the substrate using an etching solution in an etching treatment section; a discharge step of discharging the etching liquid from the etching treatment unit to a discharge flow path; a solid silica passing step of causing the etching liquid discharged to the discharge flow path in the discharge step to pass through a silica containing portion containing a plurality of solid silicas; and a cooling step of cooling the solid silicon dioxide, In the cooling step, the solid silicon dioxide is cooled so that the temperature of the solid silicon dioxide becomes lower than the temperature of the etching liquid flowing into the silicon dioxide storage portion.

17. The substrate processing method according to claim 16, wherein: Also includes: a concentration measuring step of measuring the silicon concentration in the etching solution after passing through the silicon dioxide receiving portion; as well as a determination step of determining whether the silicon concentration measured in the concentration measurement step is below a predetermined threshold value; The recovery step or the return step is selectively performed in such a manner that, when it is determined in the determination step that the silicon concentration measured in the concentration measurement step is below the threshold value, a recovery step is performed in which the etching liquid tank recovers the etching liquid after passing through the silica storage section; and when it is determined in the determination step that the silicon concentration measured in the concentration measurement step is not below the threshold value, a return step is performed in which the etching liquid is returned to the upstream side of the silica storage section in the discharge flow path.

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