Device for treating substrate and method for treating substrate

Abstract

A device for treating a substrate which comprises: a treatment part in which an aqueous solution containing hydrofluoric acid, nitric acid, and phosphoric acid is fed to the substrate; a collecting part which collects the aqueous solution from the treatment part; a regulation part in which the concentrations of the components in the aqueous solution collected by the collection part are regulated; a feeding part which feeds, to the treatment part, the aqueous solution having undergone the regulation in the regulation part; and a control unit which controls the regulation part. The regulation part has both a concentration meter for determining the concentration of hydrofluoric acid in the aqueous solution and a replenishment part in which the aqueous solution is replenished by supplying hydrofluoric acid, nitric acid, and phosphoric acid thereto. The control unit controls the replenishment so that hydrofluoric acid, nitric acid, and phosphoric acid are supplied to the aqueous solution in a desired proportion on the basis of the hydrofluoric acid concentration.

Description

SUBSTRATE PROCESSING APPARATUS AND SUBSTRATE PROCESSING METHOD

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

[0002] The substrate processing method described in Patent Document 1 includes a step of grinding the substrate surface and a step of removing a damaged layer formed on the substrate surface by grinding. The step of removing the damaged layer includes a step of supplying a processing liquid to the substrate surface. The processing liquid is, for example, an aqueous solution containing hydrofluoric acid and nitric acid.

[0003] Japanese Patent Application Publication No. 2018-147908

[0004] One aspect of the present disclosure provides a technique for maintaining the processing quality of a substrate and suppressing the wasteful disposal of chemicals.

[0005] A substrate processing apparatus according to one aspect of the present disclosure includes a processing unit that supplies an aqueous solution containing hydrofluoric acid, nitric acid, and phosphoric acid to a substrate, a recovery unit that recovers the aqueous solution from the processing unit, a regulator that adjusts the component concentrations of the aqueous solution recovered by the regulator, a supply unit that supplies the aqueous solution adjusted by the regulator to the processing unit, and a control unit that controls the regulator. The regulator has a concentration meter that detects the hydrofluoric acid concentration of the aqueous solution, and a supply unit that supplies hydrofluoric acid, nitric acid, and phosphoric acid to the aqueous solution. The control unit controls the supply of hydrofluoric acid, nitric acid, and phosphoric acid to the aqueous solution in a desired ratio based on the hydrofluoric acid concentration.

[0006] According to one aspect of the present disclosure, it is possible to maintain the processing quality of a substrate and prevent unnecessary disposal of chemicals.

[0007] FIG. 1 is a plan view showing a substrate processing apparatus according to an embodiment. FIG. 2 is a flowchart showing a substrate processing method according to an embodiment. FIG. 3 is a cross-sectional view showing an example of an etching apparatus. FIG. 4 is a diagram showing an example of a liquid circuit for an etching liquid. FIG. 5 is a diagram showing an example of a change in component concentration over time when a replenishing unit does not replenish chemical liquid. FIG. 6 is a diagram showing an example of a change in hydrofluoric acid concentration over time when a replenishing unit replenishes chemical liquid. FIG. 7 is a flowchart showing an example of adjustment of component concentration.

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same or corresponding components are denoted by the same reference numerals, and descriptions thereof may be omitted. In this specification, the X-axis direction, the Y-axis direction, and the Z-axis direction are perpendicular to each other. The X-axis direction and the Y-axis direction are horizontal directions, and the Z-axis direction is vertical.

[0009] A substrate processing apparatus 1 according to one embodiment will be described with reference to Fig. 1 . The substrate processing apparatus 1 processes a substrate W. The substrate W includes, for example, a semiconductor wafer such as a silicon wafer. The substrate W may include multiple devices formed on the semiconductor wafer. The devices include, for example, electronic circuits. The substrate W may also be a laminated substrate formed by stacking multiple semiconductor wafers. A laminated substrate is obtained by bonding multiple semiconductor wafers together.

[0010] The substrate processing apparatus 1 includes a loading / unloading station 10, a processing station 20, and a controller 90. The loading / unloading station 10 and the processing station 20 are arranged in this order from the negative side of the X axis to the positive side of the X axis.

[0011] The loading / unloading station 10 includes a mounting table 11. Cassettes C1 and C2 are placed on the mounting table 11. Cassette C1 stores substrates W before processing. Cassette C2 stores substrates W after processing. The number of cassettes C1 and C2 is not particularly limited. A cassette not shown may store substrates W that have become defective during processing.

[0012] The loading / unloading station 10 includes a first transfer region 12 and a first transfer device 13. The first transfer region 12 is adjacent to the mounting table 11 and a transition device 21, which will be described later. The first transfer device 13 transfers the substrate W between a plurality of devices adjacent to the first transfer region 12. The first transfer device 13 includes a transfer arm that holds the substrate W and a drive unit that moves or rotates the transfer arm. The transfer arm is capable of moving horizontally (in both the X-axis and Y-axis directions) and vertically, and of rotating about a vertical axis. Multiple transfer arms may be provided.

[0013] The processing station 20 includes a transition device 21, a second transfer region 22, a second transfer device 23, a grinding device 24, a cleaning device 25, and an etching device 26. The arrangement and number of devices constituting the processing station 20 are not limited to those shown in FIG.

[0014] The transition device 21 temporarily stores the substrates W. The transition device 21 is provided between the first transport region 12 and the second transport region 22, and relays the substrates W between the first transport device 13 and the second transport device 23.

[0015] The second transfer region 22 is adjacent to the transition device 21, the grinding device 24, the cleaning device 25, and the etching device 26. The second transfer device 23 transfers the substrate W between the multiple devices adjacent to the second transfer region 22. The second transfer device 23 has a transfer arm that holds the substrate W and a drive unit that moves or rotates the transfer arm. The transfer arm is capable of moving in the horizontal direction (both in the X-axis direction and the Y-axis direction) and the vertical direction, and of rotating about the vertical axis. Multiple transfer arms may be provided.

[0016] The grinding device 24 grinds the substrate W. This allows the substrate W to be thinned. The grinding device 24 may grind one side of the substrate W, or may grind both sides of the substrate W. When grinding both sides of the substrate W, one side and the opposite side of the substrate W may be ground by separate grinding devices 24. The grinding device 24 grinds the substrate W, for example, by pressing a grinding wheel against the substrate W while rotating the grinding wheel and the substrate W.

[0017] The cleaning device 25 cleans the substrate W. It can remove grinding debris adhering to the substrate W. When the grinding device 24 grinds both sides of the substrate W, the cleaning device 25 cleans both sides of the substrate W. One side and the other side of the substrate W may be cleaned by different cleaning devices 25. The cleaning device 25 scrubs the substrate W with, for example, a brush or a sponge.

[0018] The etching device 26 etches the substrate W by supplying a processing liquid to the substrate W. Damaged layers caused by grinding the substrate W can be removed, and cracks in the substrate W can be suppressed. When the grinding device 24 grinds both surfaces of the substrate W, the etching device 26 etches both surfaces of the substrate W. One surface and the other surface of the substrate W may be etched by separate etching devices 26. Details of the etching device 26 will be described later.

[0019] The control device 90 is, for example, a computer, and includes an arithmetic unit 91 such as a CPU (Central Processing Unit), and a storage unit 92 such as a memory. The storage unit 92 stores programs for controlling various processes executed in the substrate processing apparatus 1. The control device 90 controls the operation of the substrate processing apparatus 1 by causing the arithmetic unit 91 to execute the programs stored in the storage unit 92. A unit controller for controlling the operation of each unit constituting the substrate processing apparatus 1 may be provided, and a system controller for overall control of multiple unit controllers may be provided. The unit controllers and system controller may form the control device 90. The control device 90 is an example of a controller.

[0020] Next, a substrate processing method according to one embodiment will be described with reference to Figure 2. The substrate processing method includes, for example, steps S101 to S103. Steps S101 to S103 are performed under the control of a control device 90.

[0021] First, the first transport device 13 takes the substrate W out of the cassette C1 and transports it to the transition device 21. Next, the second transport device 23 takes the substrate W out of the transition device 21 and transports it to the grinding device 24.

[0022] Next, the grinding device 24 grinds the substrate W (step S101), thereby thinning the substrate W. Thereafter, the second transport device 23 removes the substrate W from the grinding device 24 and transports it to the cleaning device 25.

[0023] Next, the cleaning device 25 cleans the substrate W (step S102), thereby removing grinding debris adhering to the substrate W. Thereafter, the second transport device 23 removes the substrate W from the cleaning device 25 and transports it to the etching device 26.

[0024] Next, the etching device 26 etches the substrate W (step S103). This can remove a damaged layer caused by grinding the substrate W and suppress cracking of the substrate W. Thereafter, the second transport device 23 takes the substrate W out of the etching device 26 and transports it to the transition device 21.

[0025] Finally, the first transport device 13 takes the substrate W out of the transition device 21 and stores it in the cassette C2.

[0026] The substrate processing method may include step S103. For example, the substrate processing method may include forming a modified layer inside the substrate W with a laser beam and dividing the substrate W starting from the modified layer, instead of grinding the substrate W (step S101). In either case, the substrate W can be thinned.

[0027] Next, an example of an etching apparatus 26 will be described with reference to Figure 3. The etching apparatus 26 is an example of a processing section. The processing section supplies a processing liquid L to the substrates W. In this embodiment, the processing section is of a single-wafer type that processes substrates W one by one, but it may also be of a batch type that processes multiple substrates W simultaneously. A single-wafer type processing section will be described below.

[0028] The etching device 26 includes, for example, a processing vessel 31 , a substrate holder 34 , a substrate rotation unit 35 , a nozzle 36 , a nozzle movement unit 37 , a cup 38 , a drain pipe 39 , and an exhaust pipe 40 .

[0029] The processing vessel 31 accommodates a substrate holder 34 and the like. A gate 32 and a gate valve 33 for opening and closing the gate 32 are provided on the sidewall of the processing vessel 31. The substrate W is loaded into the processing vessel 31 through the gate 32 by the second transfer device 23 (see FIG. 1 ). Next, the substrate W is processed with the processing liquid L inside the processing vessel 31. Thereafter, the substrate W is unloaded from the processing vessel 31 through the gate 32 by the second transfer device 23.

[0030] The substrate holder 34 is provided inside the processing vessel 31 and holds the substrate W horizontally. The substrate holder 34 has, for example, claws 34a that hold the outer periphery of the substrate W. A plurality of claws 34a are provided at equal intervals in the circumferential direction of the substrate W. Although not shown, the substrate holder 34 may vacuum-suck the lower surface of the substrate W.

[0031] The substrate rotating unit 35 rotates the substrate holding unit 34, thereby rotating the substrate W together with the substrate holding unit 34. The substrate rotating unit 35 includes a motor and the like.

[0032] The nozzle 36 supplies the processing liquid L to the substrate W. The nozzle 36 supplies the processing liquid L to, for example, the rotating substrate W. The processing liquid L includes, for example, an etching liquid and a rinse liquid. The etching liquid is a mixture of hydrofluoric acid (HF) and nitric acid (HNO ３ ) and phosphoric acid (H ３ P.O. ４ The rinsing liquid is a pure water such as DIW (deionized water). The nozzle 36 supplies the etching liquid and the rinsing liquid to the substrate W in this order. The etching liquid and the rinsing liquid may be supplied by separate nozzles 36. The nozzle 36 is connected to a supply unit 70, which will be described later.

[0033] The nozzle moving unit 37 moves the nozzle 36 in the horizontal direction. The nozzle moving unit 37 moves the nozzle 36, for example, in the radial direction of the substrate W. The nozzle moving unit 37 includes, for example, an arm 37 a that holds the nozzle 36 and a drive unit 37 b that rotates the arm 37 a.

[0034] The cup 38 surrounds the outer periphery of the substrate W held by the substrate holder 34 and collects the processing liquid L that splashes from the outer periphery of the substrate W.

[0035] The drain pipe 39 and the exhaust pipe 40 are provided at the bottom of the cup 38. The drain pipe 39 discharges the processing liquid L that has accumulated inside the cup 38. The drain pipe 39 is connected to a recovery unit 50, which will be described later. The exhaust pipe 40 discharges gas that has accumulated inside the cup 38.

[0036] Next, an example of a liquid circuit for the etching liquid L1 will be described with reference to Fig. 4. The etching liquid L1 is a mixture of HF and HNO ３ and H３ P.O. ４ It is an aqueous solution containing HNO ３ When the substrate W is a silicon wafer, etching of the silicon wafer is considered to proceed according to the following chemical reaction formulas (1) and (2): (1) Si + HNO ３ +H ２ O → SiO ２ +HNO ２ +H ２ (2) SiO ２ +6HF→H ２ SiF ６ +2H ２ O Furthermore, H ３ P.O. ４ is a component that adjusts the viscosity of the etching solution L1.

[0037] 4, the substrate processing apparatus 1 includes a recovery unit 50, an adjustment unit 60, and a supply unit 70. The recovery unit 50 recovers the etching liquid L1 from the etching device 26. The adjustment unit 60 adjusts the component concentrations of the etching liquid L1 recovered by the recovery unit 50. The supply unit 70 supplies the etching liquid L1, the component concentrations of which have been adjusted by the adjustment unit 60, to the etching device 26. The substrate processing apparatus 1 reuses the etching liquid L1, thereby reducing the amount of etching liquid L1 that is discarded.

[0038] The recovery unit 50 has a recovery line 51. The recovery line 51 connects the etching device 26 and the adjustment unit 60. For example, the recovery line 51 connects the drain pipe 39 (see FIG. 3 ) of the etching device 26 and the storage tank 61 of the adjustment unit 60. A filter 52 may be provided midway along the recovery line 51. The filter 52 collects foreign matter in the etching solution L1.

[0039] The adjusting unit 60 includes, for example, a storage tank 61, a circulation line 62, a pump 63, a filter 64, a flow meter 65, a concentration meter 66, and a replenishing unit 67. The storage tank 61 stores the etching liquid L1. The circulation line 62 extracts the etching liquid L1 from the storage tank 61 and returns it to the storage tank 61. By circulating the etching liquid L1, the component concentrations can be made uniform.

[0040] A pump 63, a filter 64, a flow meter 65, and a concentration meter 66 are provided in the circulation line 62. The pump 63 pumps out the etching solution L1. The filter 64 collects foreign matter in the etching solution L1. The flow meter 65 detects the flow rate of the etching solution L1. The control device 90 controls the pump 63 so that the detected value of the flow meter 65 becomes a set value. The concentration meter 66 detects the hydrofluoric acid concentration of the etching solution L1.

[0041] A thermometer and a heater (not shown) may be provided in the circulation line 62. The thermometer detects the temperature of the etching solution L1. The heater heats the etching solution L1. The control device 90 controls the heater so that the detected value of the thermometer becomes the set value.

[0042] The supply unit 67 supplies HF and HNO ３ and H ３ P.O. ４ For example, the replenishing unit 67 supplies HF and HNO to the reservoir 61 or the circulation line 62 (the reservoir 61 in FIG. 4). ３ and H ３ P.O. ４ The supply unit 67 supplies HF, HNO ３ or H ３ P.O. ４ The supply unit 67 may supply HF and HNO in the form of an aqueous solution. ３ and H ３ P.O. ４ may be supplied in order or simultaneously.

[0043] The replenishing unit 67 may have individual lines for each type of chemical solution. For example, an HF replenishing amount adjusting unit 67b-1 is provided midway along the individual HF line 67a-1. The HF replenishing amount adjusting unit 67b-1 may, for example, have an on-off valve, a metering tank, and an on-off valve, in this order, from upstream to downstream. The metering tank measures the amount of replenishing for one time. The HF replenishing amount adjusting unit 67b-1 may have a tank, a flow meter, a flow rate controller, and an on-off valve. In this case, the control device 90 may control the replenishing amount using a meter provided in the tank, or may control the replenishing amount using a flow meter (time integral value of flow rate). Alternatively, the HF replenishing amount adjusting unit 67b-1 may have a flow meter, a flow rate controller, and an on-off valve without a tank. In this case, the control device 90 may control the replenishing amount using a flow meter (time integral value of flow rate). The order of the flow meter, flow rate controller, and on-off valve is not particularly limited.

[0044] HNO ３ In the middle of the individual line 67a-2, for example, HNO ３ A supply amount adjusting unit 67b-2 is provided. ３ The HF supply amount adjusting section 67b-2 is configured in the same manner as the HF supply amount adjusting section 67b-1. ３ P.O. ４ In the middle of the individual line 67a-3, for example, ３ P.O. ４ A supply amount adjusting unit 67b-3 is provided. ３ P.O. ４ The HF supply amount adjusting section 67b-3 is configured in the same manner as the HF supply amount adjusting section 67b-1.

[0045] The waste unit 68 wastes the etching liquid L1 stored in the storage tank 61. The etching liquid L1 is disposed of periodically, and is disposed of appropriately according to, for example, the time elapsed since the etching liquid L1 was replaced or the number of processed substrates W. The waste unit 68 has a discharge line 68a connected to the storage tank 61 and an opening / closing valve 68b that opens and closes the flow path of the discharge line 68a.

[0046] The supply unit 70 includes, for example, a supply line 71, a flow meter 72, a flow rate controller 73, and an on-off valve 74. The supply line 71 connects the adjustment unit 60 and the etching device 26. For example, the supply line 71 connects the circulation line 62 of the adjustment unit 60 and the nozzle 36 of the etching device 26 (see FIG. 3 ).

[0047] A flow meter 72, a flow rate controller 73, and an on-off valve 74 are provided in the supply line 71. The flow meter 72 detects the flow rate of the etching liquid L1. The flow rate controller 73 controls the flow rate of the etching liquid L1. The control device 90 controls the flow rate controller 73 so that the detected value of the flow meter 72 becomes a set value. The on-off valve 74 opens and closes the flow path of the supply line 71.

[0048] As described above, the etching solution L1 is reused. Therefore, if the replenishing unit 67 does not replenish the various chemical solutions, the concentration of each component changes over time as shown in FIG. 5. Specifically, the concentration of HF and HNO ３ Concentration and H ３ P.O. ４ The concentration decreases and H ２ O concentration and H ２ SiF ６ The concentration increases. This is clear from the above chemical reaction formulas (1) and (2). ３ P.O. ４ The concentration decreases due to etching of the substrate W. ２ This is because O is produced. ２ Due to the generation of O, the relative H ３ P.O. ４ The concentration decreases.

[0049] By supplying the chemical solution by the supply unit 67, it is possible to suppress changes in the component concentrations and suppress deterioration in the processing quality of the substrate W. In order to maintain the processing quality of the substrate W, it is necessary to maintain the HF concentration and HNO concentration in the respective component concentrations. ３ Concentration and H ３ P.O. ４ It is important to suppress the change in concentration.

[0050] However, it takes time to control the concentrations of all three components. For example, after HF is replenished so that the HF concentration reaches the set value, HNO３ HNO ３ To converge all three component concentrations to the set value, HF is replenished based on the detected value of HF concentration, and HNO is replenished based on the detected value of HF concentration. ３ HNO based on the detected concentration ３ Supply and H ３ P.O. ４ H based on the detected concentration ３ P.O. ４ As a result, if the liquid level of the etching liquid L1 in the reservoir tank 61 exceeds the upper limit, the etching liquid L1 stored in the reservoir tank 61 will have to be discarded.

[0051] In order to prevent unnecessary waste of chemicals, HF and HNO are used based on the number of processed substrates W. ３ and H ３ P.O. ４ However, in this case, the HF concentration and HNO ３ Concentration and H ３ P.O. ４ Since neither the concentration nor the concentration is monitored, even if a concentration abnormality occurs due to disturbance or the like, the concentration abnormality cannot be detected, which may result in a deterioration in the processing quality of the substrate W.

[0052] Therefore, in this embodiment, only the HF concentration, which is the most important for etching silicon among the three component concentrations, is controlled. The etching rate of the substrate W mainly depends on the HF concentration. In this embodiment, HF and HNO are controlled based on the HF concentration. ３ and H ３ P.O. ４ HF and HNO are added in the desired ratio. ３ and H ３ P.O. ４ The amount of HF replenishment and HNO are replenished at a desired ratio based on the HF concentration. ３ Supply amount and H ３ P.O. ４ The ratio of the replenishment amount is determined in advance based on, for example, the above chemical reaction formulas (1) and (2) and the target values ​​of the concentrations of each component, and is stored in advance in the storage unit 92 of the control device 90. The ratio may be any of a volume ratio, a mass ratio, and a molar ratio. The ratio may be fixed.

[0053] The control device 90 controls the HF and HNO concentration based on the HF concentration detected by the concentration meter 66. ３ and H ３ P.O. ４ The HF concentration can be maintained at a set value, and the processing quality of the substrate W can be maintained. ３ Concentration and H ３ P.O. ４ Leaving the concentration uncontrolled, i.e., HNO ３ Concentration-based HNO ３ Supplementation and H ３ P.O. ４ Concentration-based H ３ P.O. ４ By not replenishing HNO, the adjustment of the component concentration can be completed in a short time, and the wasteful disposal of the chemical solution can be suppressed. ３ Concentration and H ３ P.O. ４ The above ratios are determined so that the concentrations are maintained as close as possible to their target values.

[0054] For example, as shown in FIG. 6, the control device 90 determines whether the hydrofluoric acid concentration N is greater than or equal to a threshold value N Ｔｈ When the temperature is below 100°C, HF and HNO ３ and H ３ P.O. ４ A first control is performed in which the HF replenishment amount and the HNO replenishment amount are replenished to the etching solution L1 by a predetermined amount. ３ Supply amount and H ３ P.O. ４ The replenishment amount is determined in advance so as to achieve the desired ratio, and is also determined taking into consideration the volume of the reservoir 61. ３ Supply amount and H ３ P.O. ４ The amount of replenishment may be fixed. ３ The amount of replenishment is HNO ３ It is determined according to the amount of HF replenishment, not the concentration. ３ P.O. ４ The amount of replenishment is H ３ P.O. ４ It is determined according to the amount of HF replenishment, not the concentration.

[0055] After the first control, the control device 90 determines whether the hydrofluoric acid concentration N is equal to or lower than the threshold value NＴｈ If the concentration N of hydrofluoric acid remains below the threshold value N, the first control is performed again. Ｔｈ However, if the concentration of hydrofluoric acid cannot be recovered due to a disturbance or the like, the first control is performed again to raise the concentration of hydrofluoric acid N to the threshold value N Ｔｈ You can recover more than that.

[0056] The control device 90 detects whether the hydrofluoric acid concentration N is greater than or equal to the threshold value N Ｔｈ While the temperature is below 100°C, HF and HNO ３ and H ３ P.O. ４ The control device 90 may perform a second control in which the hydrofluoric acid concentration N is continuously replenished to the etching solution L1 at a desired flow rate ratio. Ｔｈ When the pressure returns to the above level, the second control is stopped.

[0057] Next, an example of the adjustment of the component concentrations (first control) will be described with reference to Fig. 7. The processes from step S201 onwards shown in Fig. 7 are performed under the control of the control device 90. The processes from step S201 onwards are performed periodically.

[0058] First, the concentration meter 66 detects the hydrofluoric acid concentration N of the etching solution L1 (step S201). Next, the control device 90 detects whether the hydrofluoric acid concentration N is equal to or exceeds the threshold value N Ｔｈ (Step S202). Ｔｈ If the result is equal to or greater than the above (step S202, NO), there is no need to adjust the component concentrations, and the control device 90 ends the current process.

[0059] On the other hand, the hydrofluoric acid concentration N is equal to the threshold value N Ｔｈ If the etching rate is lower than 0.05% (YES in step S202), the etching rate of the substrate W is low, so the replenishing unit 67 is ３ and H ３ P.O. ４ The etching solution L1 is replenished with the respective predetermined amounts (step S203). After that, after a predetermined time has elapsed, the processing from step S201 onwards is carried out again.

[0060] Even if step S203 is performed a set number of times, the hydrofluoric acid concentration N does not exceed the threshold value N ＴｈIf the temperature remains below 100°C, the control device 90 may interrupt the processing of the substrate W and issue an alarm. The alarm is issued using an alarm device. The alarm device is, for example, a display device, a warning light, or a buzzer.

[0061] Although the embodiments of the substrate processing apparatus and substrate processing method according to the present disclosure have been described above, the present 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 naturally fall within the technical scope of the present disclosure.

[0062] This application claims priority based on Japanese Patent Application No. 2022-101701 filed with the Japan Patent Office on June 24, 2022, the entire contents of which are incorporated herein by reference.

[0063] REFERENCE SIGNS LIST 1 Substrate processing apparatus 26 Etching apparatus (processing section) 50 Recovery section 60 Adjustment section 66 Concentration meter 67 Replenishment section 70 Supply section 90 Control device (control section) W Substrate

Claims

1. A substrate processing apparatus comprising: a processing unit that supplies an aqueous solution containing hydrofluoric acid, nitric acid, and phosphoric acid to a substrate; a recovery unit that recovers the aqueous solution from the processing unit; an adjustment unit that adjusts the component concentrations of the aqueous solution recovered by the recovery unit; a supply unit that supplies the aqueous solution adjusted by the adjustment unit to the processing unit; and a control unit that controls the adjustment unit, wherein the adjustment unit has a concentration meter that detects the hydrofluoric acid concentration of the aqueous solution and a supply unit that supplies hydrofluoric acid, nitric acid, and phosphoric acid to the aqueous solution, and the control unit controls the supply of hydrofluoric acid, nitric acid, and phosphoric acid to the aqueous solution in a desired ratio based on the hydrofluoric acid concentration.

2. The substrate processing apparatus according to claim 1, wherein the control unit performs a first control of replenishing the aqueous solution with predetermined amounts of hydrofluoric acid, nitric acid, and phosphoric acid when the hydrofluoric acid concentration falls below a threshold value.

3. The substrate processing apparatus according to claim 2, wherein the control unit performs the first control again if the hydrofluoric acid concentration remains below the threshold value after performing the first control.

4. The substrate processing apparatus according to claim 1, wherein the control unit performs second control to continuously replenish the aqueous solution with hydrofluoric acid, nitric acid, and phosphoric acid at a desired flow rate ratio while the hydrofluoric acid concentration is below a threshold value.

5. A substrate processing apparatus according to any one of claims 1 to 4, wherein the adjustment unit has a storage tank for storing the aqueous solution recovered by the recovery unit, and a circulation line for removing the aqueous solution from the storage tank and returning it to the storage tank, and the supply unit supplies hydrofluoric acid, nitric acid, and phosphoric acid in a desired ratio to the storage tank or the circulation line.

6. A substrate processing apparatus according to any one of claims 1 to 4, comprising: a grinding unit that grinds the substrate; and a transport unit that transports the substrate from the grinding unit to the processing unit, wherein the processing unit supplies the aqueous solution to the substrate ground by the grinding unit.

7. A substrate processing method comprising: supplying an aqueous solution containing hydrofluoric acid, nitric acid, and phosphoric acid to a substrate in a processing section; recovering the aqueous solution from the processing section; adjusting component concentrations of the aqueous solution recovered from the processing section; and supplying the aqueous solution with the adjusted component concentrations to the processing section, wherein adjusting the component concentrations includes detecting a hydrofluoric acid concentration in the aqueous solution; and replenishing hydrofluoric acid, nitric acid, and phosphoric acid to the aqueous solution in a desired ratio based on the hydrofluoric acid concentration.

8. The substrate processing method according to claim 7, wherein adjusting the component concentrations includes replenishing the aqueous solution with predetermined amounts of hydrofluoric acid, nitric acid, and phosphoric acid when the hydrofluoric acid concentration is below a threshold value.

9. The substrate processing method of claim 8, wherein adjusting the component concentrations includes, if the hydrofluoric acid concentration remains below the threshold value after the predetermined amounts of hydrofluoric acid, nitric acid, and phosphoric acid have been replenished to the aqueous solution, the predetermined amounts of hydrofluoric acid, nitric acid, and phosphoric acid are replenished to the aqueous solution again.

10. The substrate processing method of claim 7, wherein adjusting the component concentrations includes continuously replenishing the aqueous solution with hydrofluoric acid, nitric acid, and phosphoric acid at a desired flow rate ratio while the hydrofluoric acid concentration is below a threshold value.

11. The substrate processing method according to any one of claims 7 to 10, wherein adjusting the component concentrations includes storing the aqueous solution recovered from the processing section in a storage tank, removing the aqueous solution from the storage tank to a circulation line and returning it to the storage tank from the circulation line, and replenishing the storage tank or the circulation line with hydrofluoric acid, nitric acid, and phosphoric acid in a desired ratio.

12. The substrate processing method according to any one of claims 7 to 10, further comprising: grinding the substrate; and supplying the aqueous solution to the ground substrate.