Substrate processing apparatus and substrate processing method

Abstract

To provide a technique of suppressing an increase of particles.SOLUTION: A substrate processing apparatus comprises a tank, a circular line, a branch line, a processing part, an exhaust part, a supply part, and a control part. The control part includes a first determination part, a first replenishment control part, a calculation part, and a second replenishment control part. The first determination part determines whether or not an accumulation amount of the processing liquid in the tank is less than a lower limit value. The first replenishment control part replenishes the tank with the processing liquid by the supply part when the first determination part determines that the accumulation amount is less than the lower limit value. The calculation part calculates a replenishment amount for replenishing the tank with the processing liquid per a setting time by the supply part. The second replenishment control part reduces the accumulation amount of the tank by the exhaust part when the calculation value of the replenishment amount calculated by the calculation part is less than a setting value, and the tank is replenished with the processing liquid by the supply part.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] The substrate processing system of Patent Document 1 includes one or more processing units, a storage unit, a liquid storage unit, an acquisition unit, a setting unit, a detection unit, a recognition unit, and a detection unit. The one or more processing units perform processing on a substrate using a processing liquid. The storage unit stores processing plan information indicating the execution timing of a plurality of continuous processes for a plurality of substrate groups in the one or more processing units. The liquid storage unit stores the processing liquid. The acquisition unit acquires numerical values related to the state of the processing liquid. The setting unit sets the replacement timing of the processing liquid in the liquid storage unit based on the numerical values acquired by the acquisition unit and rules related to the life of the processing liquid. The detection unit detects a standby state in which continuous processing is not being executed by the one or more processing units at the replacement timing. The recognition unit recognizes the duration of the standby state based on the processing plan information. The detection unit detects a liquid replaceable state in which the duration is equal to or longer than a preset reference time.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A first aspect of the present disclosure provides a technique for suppressing an increase in particles due to circulation of a processing liquid. A second aspect of the present disclosure provides a technique for suppressing an increase in particles due to replacement of a processing liquid.

Means for Solving the Problems

[0005] The substrate processing apparatus according to the first aspect of the present disclosure includes a tank, a circulation line, a branch line, a processing unit, a discharge unit, a supply unit, and a control unit. The tank stores a processing liquid. The circulation line takes out the processing liquid from the tank and returns it to the tank. The branch line branches off from the circulation line. The processing unit supplies the processing liquid to a substrate at the end of the branch line. The discharge unit reduces the storage amount of the processing liquid stored in the tank. The supply unit supplies new processing liquid to the tank. The control unit controls the processing unit, the discharge unit, and the supply unit. The control unit includes a first determination unit, a first replenishment control unit, a calculation unit, and a second replenishment control unit. The first determination unit determines whether or not the storage amount of the processing liquid in the tank is less than a lower limit value. The first replenishment control unit replenishes the tank with the processing liquid by the supply unit when the first determination unit determines that the storage amount is less than the lower limit value. The calculation unit calculates a replenishment amount for replenishing the tank with the processing liquid per unit time by the supply unit. The second replenishment control unit, when the calculated value of the replenishment amount calculated by the calculation unit is less than a set value, reduces the storage amount of the tank by the discharge unit and replenishes the tank with the processing liquid by the supply unit.

[0006] The substrate processing apparatus according to the second aspect of the present disclosure includes a tank, a circulation line, a pump, a branch line, a processing unit, a discharge unit, a supply unit, and a control unit. The tank stores a processing liquid. The circulation line takes out the processing liquid from the tank and returns it to the tank. The pump is provided in the circulation line. The branch line branches from the circulation line. The processing unit supplies the processing liquid to a substrate at the end of the branch line. The discharge unit reduces the storage amount of the processing liquid stored in the tank. The supply unit supplies new processing liquid to the tank. The control unit controls the pump, the processing unit, the discharge unit, and the supply unit. The control unit has a first liquid exchange control unit. When receiving a liquid exchange command for exchanging the processing liquid during circulation, the first liquid exchange control unit reduces the storage amount of the tank by the discharge unit and supplies the processing liquid to the tank by the supply unit while circulating the processing liquid by the pump.

Effect of the Invention

[0007] According to the first aspect of the present disclosure, an increase in particles due to the circulation of the processing liquid can be suppressed. Further, according to the second aspect of the present disclosure, an increase in particles due to the exchange of the processing liquid can be suppressed.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

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Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

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Figure 15

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same reference numerals, and the description thereof may be omitted.

[0010] Referring to FIG. 1, the substrate processing apparatus 1 according to the present embodiment will be described. The substrate processing apparatus 1 includes a processing unit 10. The processing unit 10 processes a substrate by supplying a processing liquid to the substrate. In the present embodiment, the processing unit 10 is a single-wafer type that processes substrates one by one.

[0011] Note that the processing unit 10 may be a batch type that processes multiple substrates simultaneously. The batch-type processing unit 10 has a processing tank, and the substrate is immersed in the processing liquid stored in the processing tank. In this case, the substrate W may be immersed in the processing liquid in a vertically standing state.

[0012] As shown in FIG. 2, the single-wafer type processing unit 10 includes, for example, a processing container 11, a holding unit 12 that holds the substrate W horizontally, a rotating unit 13 that rotates the holding unit 12 about a vertical rotation axis 14, and a nozzle 16 that discharges liquid onto the upper surface of the substrate W held by the holding unit 12.

[0013] The processing container 11 houses the substrate W inside. The processing container 11 has a gate (not shown) and a gate valve (not shown) that opens and closes the gate. The substrate W is carried into the inside of the processing container 11 through the gate, processed with the processing liquid L inside the processing container 11, and then carried out of the processing container 11 through the gate.

[0014] The holding unit 12 holds the substrate W carried into the inside of the processing container 11 horizontally. The holding unit 12 holds the substrate W horizontally such that the surface of the substrate W on which the polysilicon film is formed faces upward and the center of the substrate W coincides with the rotation center line of the rotation axis 14. The holding unit 12 is a mechanical chuck in FIG. 2, but may be a vacuum chuck or an electrostatic chuck, etc. The holding unit 12 may be a rotatable spin chuck.

[0015] The rotating unit 13 includes, for example, a vertical rotation axis 14 and a rotation motor 15 that rotates the rotation axis 14. The rotational driving force of the rotation motor 15 may be transmitted to the rotation axis 14 through a rotation transmission mechanism such as a timing belt or a gear. When the rotation axis 14 is rotated, the holding unit 12 is also rotated.

[0016] The nozzle 16 has a discharge port for discharging the processing liquid L onto the substrate W held by the holding unit 12. The nozzle 16 is arranged above the substrate W with the discharge port facing downward, for example, and supplies the processing liquid L to the central portion of the substrate W. The processing liquid L is supplied to the central portion of the rotating substrate W and spreads over the entire upper surface of the substrate W by centrifugal force to form a liquid film. The processing unit 10 may include a moving unit 19 that moves the nozzle 16. The moving unit 19 may move the nozzle 16 in the radial direction of the substrate W or in the vertical direction.

[0017] The processing liquid L includes, for example, a chemical solution, a rinse solution, and a drying solution. One nozzle 16 may discharge a plurality of processing liquids L in sequence, or a plurality of nozzles 16 may discharge different processing liquids L in sequence. A plurality of chemical solutions may be supplied to the substrate W in sequence, and a rinse solution may be supplied to the substrate W therebetween.

[0018] The chemical solution is not particularly limited, but is, for example, DHF (dilute hydrofluoric acid), SC-1 (aqueous solution containing ammonium hydroxide and hydrogen peroxide), SC-2 (aqueous solution containing hydrogen chloride and hydrogen peroxide), or SPM (aqueous solution containing sulfuric acid and hydrogen peroxide). The chemical solution may be an etching solution for etching the substrate W.

[0019] The rinse solution is, for example, DIW (deionized water). The rinse solution is used to remove the chemical solution. The rinse solution is supplied to the central portion of the rotating substrate W and spreads over the entire upper surface of the substrate W by centrifugal force to wash away the chemical solution remaining on the upper surface of the substrate W. As a result, a liquid film of the rinse solution is formed on the upper surface of the substrate W. The rinse solution may be supplied to the substrate W after one chemical solution is supplied to the substrate W and before another chemical solution is supplied to the substrate W.

[0020] The drying liquid is an organic solvent such as IPA (isopropyl alcohol). The organic solvent has a lower surface tension than the rinse liquid. Therefore, it is possible to suppress the collapse of the uneven pattern due to the surface tension. The drying liquid is supplied to the central portion of the rotating substrate W, spreads wet over the entire upper surface of the substrate W by centrifugal force, and replaces the rinse liquid remaining on the upper surface of the substrate W. As a result, a liquid film of the drying liquid is formed on the upper surface of the substrate W.

[0021] The processing unit 10 has a cup 17 that recovers the processing liquid L supplied to the substrate W. The cup 17 surrounds the periphery of the substrate W held by the holding unit 12 and receives the processing liquid L scattered from the periphery of the substrate W. The cup 17 does not rotate together with the rotation shaft 14 in this embodiment, but may rotate together with the rotation shaft 14. A drain pipe 17a for discharging the liquid accumulated inside the cup 17 and an exhaust pipe 17b for discharging the gas accumulated inside the cup 17 are provided on the bottom wall of the cup 17.

[0022] As shown in FIG. 1, the substrate processing apparatus 1 includes a tank 20 that stores the processing liquid L, a circulation line 21 that takes out the processing liquid L from the tank 20 and returns it to the tank 20, and a branch line 22 that branches from the circulation line 21. The processing unit 10 supplies the processing liquid L to the substrate W at the tip of the branch line 22. The processing liquid L is not particularly limited, but is, for example, IPA.

[0023] The tank 20 stores the processing liquid L. The processing liquid L is circulated from the tank 20 through the circulation line 21 and back to the tank 20. For example, a pump 23, a flow meter 24, a heater 25, a thermometer (not shown), and a filter 26 are provided in the middle of the circulation line 21. Note that the arrangement of these devices 23 to 26 is not limited to the arrangement in FIG. 1.

[0024] The pump 23 circulates the processing liquid L. The flow meter 24 measures the flow rate of the processing liquid L. The control unit 90 controls the pump 23 so that the measured value of the flow meter 24 becomes the set value. The heater 25 heats the processing liquid L. The thermometer measures the temperature of the processing liquid L. The control unit 90 controls the heater 25 so that the measured value of the thermometer becomes the set value. The processing liquid L at a desired temperature can be supplied to the substrate W. The filter 26 collects foreign matters in the processing liquid L.

[0025] The branch line 22 connects the circulation line 21 and the nozzle 16 of the processing unit 10. The branch line 22 is provided for each processing unit 10. When the processing unit 10 is of the batch type, the branch line 22 connects the circulation line 21 and the processing tank of the processing unit 10. For example, a flow meter 27, a flow controller 28, and an on-off valve 29 are provided in the middle of the branch line 22. Note that the arrangement of these devices 27 to 29 is not limited to the arrangement in FIG. 1.

[0026] When the on-off valve 29 opens the branch line 22, the branch line 22 supplies the processing liquid L to the processing unit 10. The flow meter 27 measures the flow rate of the processing liquid L. The control unit 90 controls the flow controller 28 so that the measured value of the flow meter 27 becomes the set value. On the other hand, when the on-off valve 29 closes the branch line 22, the branch line 22 stops supplying the processing liquid L to the processing unit 10.

[0027] A reflux line 30 may be provided in the middle of the branch line 22. The reflux line 30 branches from the branch line 22 and returns the processing liquid L to the tank 20. The reflux line 30 is provided for each processing unit 10. For example, an on-off valve 31 is provided in the middle of the reflux line 30.

[0028] When the on-off valve 29 closes the branch line 22 and the on-off valve 31 opens the reflux line 30, the processing liquid L is returned to the tank 20 without being supplied to the processing unit 10. Even while the processing unit 10 does not consume the processing liquid L, the processing liquid L heated by the heater 25 can continue to flow into a part of the branch line 22, and the decrease in the temperature of the processing liquid L in the branch line 22 can be suppressed.

[0029] On one hand, when the on-off valve 29 opens the branch line 22 and the on-off valve 31 closes the reflux line 30, the processing liquid L is supplied to the processing unit 10 without being returned to the tank 20. The processing liquid L supplied to the processing unit 10 is consumed in the processing unit 10. That is, the processing liquid L supplied to the processing unit 10 is discharged outside the substrate processing apparatus 1 and not returned to the tank 20. As a result, the storage amount H of the processing liquid L stored in the tank 20 decreases.

[0030] The substrate processing apparatus 1 includes a discharge unit 40 that reduces the storage amount H of the processing liquid L separately from the processing unit 10. The discharge unit 40 reduces the storage amount H of the processing liquid L, for example, when replacing the processing liquid L to suppress deterioration of the processing liquid L. The discharge unit 40 includes, for example, a first discharge unit 41 and a second discharge unit 42. Note that the discharge unit 40 may include only the first discharge unit 41 or only the second discharge unit 42.

[0031] The first discharge unit 41 includes a first discharge line 43 connected to the tank 20 and a first on-off valve 44 that opens and closes the first discharge line 43. When the first on-off valve 44 opens the first discharge line 43, the first discharge line 43 discharges the processing liquid L from the tank 20, reducing the storage amount H of the processing liquid L. On the other hand, when the first on-off valve 44 closes the first discharge line 43, the first discharge line 43 stops discharging the processing liquid L from the tank 20.

[0032] The second discharge unit 42 includes a second discharge line 45 connected to the circulation line 21 and a second on-off valve 46 that opens and closes the second discharge line 45. When the second on-off valve 46 opens the second discharge line 45, the second discharge line 45 discharges the processing liquid L from the circulation line 21, reducing the storage amount H of the processing liquid L. On the other hand, when the second on-off valve 46 closes the second discharge line 45, the second discharge line 45 stops discharging the processing liquid L from the circulation line 21.

[0033] The substrate processing apparatus 1 includes a supply unit 50 that supplies a new processing liquid L to a tank 20. The supply unit 50 includes a supply line 51 connected to the tank 20. The new processing liquid L passes through the supply line 51 and is replenished into the tank 20. For example, a flow meter 52, a flow controller 53, and an on-off valve 54 are provided in the middle of the supply line 51. Note that the arrangement of these devices 52 to 54 is not limited to the arrangement in FIG. 1.

[0034] When the on-off valve 54 opens the supply line 51, the supply line 51 supplies the new processing liquid L to the tank 20. The flow meter 52 measures the flow rate of the processing liquid L. The control unit 90 controls the flow controller 53 so that the measured value of the flow meter 52 becomes the set value. On the other hand, when the on-off valve 54 closes the supply line 51, the supply line 51 stops supplying the new processing liquid L to the tank 20.

[0035] The substrate processing apparatus 1 includes a plurality of detectors 61 to 64 that detect the storage amount H of the processing liquid L in the tank 20. The plurality of detectors 61 to 64 are installed at different heights and detect whether the processing liquid L is present at each installation position. Although not shown, the substrate processing apparatus 1 may include a float-type detector, and the number of detectors may be one.

[0036] The substrate processing apparatus 1 includes a control unit 90. The control unit 90 is, for example, a computer and includes a CPU (Central Processing Unit) 91 and a storage medium 92 such as a memory. A program for controlling various processes executed in the substrate processing apparatus 1 is stored in the storage medium 92. The control unit 90 controls the operation of the substrate processing apparatus 1 by causing the CPU 91 to execute the program stored in the storage medium 92.

[0037] As shown in FIG. 3, the control unit 90 includes, for example, a substrate processing unit 101, a first determination unit 102, a first replenishment control unit 103, a calculation unit 104, a second replenishment control unit 105, a second determination unit 106, a forced stop unit 107, a first liquid exchange control unit 108, and a second liquid exchange control unit 109. Note that each functional block illustrated in FIG. 3 is conceptual, and does not necessarily have to be physically configured as illustrated.

[0038] All or part of each functional block illustrated in FIG. 3 can be functionally or physically distributed and integrated in any unit. Each processing function performed in each functional block can be realized by a program executed by a CPU for all or any part thereof, or can be realized as hardware by wired logic.

[0039] Next, with reference to FIG. 4, an example of the processing of the substrate processing unit 101 will be described. Each of steps S101 to S106 shown in FIG. 4 is performed under the control of the substrate processing unit 101. The substrate processing unit 101 processes the substrate W by supplying the processing liquid L to the substrate W.

[0040] First, a transfer device (not shown) transfers the substrate W into the processing container 11 (step S101). After placing the substrate W on the holding unit 12, the transfer device exits from the inside of the processing container 11. The holding unit 12 holds the substrate W. Thereafter, the rotating unit 13 rotates the substrate W together with the holding unit 12.

[0041] Next, the nozzle 16 supplies a chemical solution to the central portion of the rotating substrate W (step S102). The chemical solution spreads over the entire upper surface of the substrate W by centrifugal force to form a liquid film.

[0042] Next, the nozzle 16 supplies a rinse liquid to the central portion of the rotating substrate W (step S103). The rinse liquid spreads over the entire upper surface of the substrate W by centrifugal force to wash away the chemical solution remaining on the upper surface of the substrate W. As a result, a liquid film of the rinse liquid is formed on the upper surface of the substrate W.

[0043] Next, the nozzle 16 supplies the drying liquid to the center of the rotating substrate W (step S104). The drying liquid spreads wetly over the entire upper surface of the substrate W by centrifugal force, and washes away the rinse liquid remaining on the upper surface of the substrate W. As a result, a liquid film of the drying liquid is formed on the upper surface of the substrate W.

[0044] Next, the rotating unit 13 rotates the substrate W, shakes off the drying liquid remaining on the upper surface of the substrate W, and dries the substrate W (step S105). After the substrate W is dried, the rotating unit 13 stops the rotation of the substrate W.

[0045] Finally, the holding unit 12 releases the holding of the substrate W, and subsequently, a transport device (not shown) receives the substrate W from the holding unit 12 and carries out the received substrate W to the outside of the processing container 11 (step S106).

[0046] Next, with reference to FIG. 5, an example of the processing of the first determination unit 102 and the first replenishment control unit 103 will be described. The processing after step S201 shown in FIG. 5 is periodically performed while circulating the processing liquid L.

[0047] First, the first determination unit 102 determines whether or not the storage amount H of the processing liquid L in the tank 20 is less than the lower limit value Hmin (step S201). For this determination, for example, the detector 63 shown in FIG. 1 is used.

[0048] When the detector 63 does not detect the presence of the processing liquid L, the first determination unit 102 determines that the storage amount H is less than the lower limit value Hmin. On the other hand, when the detector 63 detects the presence of the processing liquid L, the first determination unit 102 determines that the storage amount H is equal to or greater than the lower limit value Hmin.

[0049] When the first determination unit 102 determines that the storage amount H is less than the lower limit value Hmin (step S201, YES), the first replenishment control unit 103 replenishes the tank 20 with a new processing liquid L by the supply unit 50 (step S202). As a result, the storage amount H becomes equal to or greater than the lower limit value Hmin.

[0050] The first replenishment control unit 103 may replenish new processing liquid L so that the storage amount H is equal to or greater than the lower limit value Hmin and equal to or less than the upper limit value Hmax. The fact that the storage amount H has reached the upper limit value Hmax is detected by the detector 64 shown in FIG. 1.

[0051] On the other hand, when the first determination unit 102 determines that the storage amount H is equal to or greater than the lower limit value Hmin (step S201, NO), the first replenishment control unit 103 does not replenish the new processing liquid L. Then, the current process ends.

[0052] Even if the processing unit 10 consumes the processing liquid L, the first replenishment control unit 103 replenishes the processing liquid L, so that the storage amount H in the tank 20 is maintained at a certain level or higher. The storage amount H in the tank 20 is maintained within an allowable range defined by the lower limit value Hmin and the upper limit value Hmax.

[0053] Next, with reference to FIG. 6, an example of the relationship between the number of particles adhering to the substrate W, the circulation time, and the temperature of the processing liquid will be described. The circulation time is the elapsed time from step S404 in FIG. 11 described later, and is the elapsed time from the completion of the liquid exchange process. Details of the liquid exchange process will be described later. In FIG. 6, the processing liquid is IPA.

[0054] As shown in FIG. 6, immediately after the liquid exchange process, the longer the circulation time, the further the filtration progresses, and the fewer the number of particles adhering to the substrate W. Filtration is to collect the particles P contained in the processing liquid L by the filter 26 as shown in FIG. 7(A).

[0055] As shown in FIG. 6, when the temperature of the processing liquid L is room temperature or 60°C, the number of particles adhering to the substrate W gradually decreases and then levels off. On the other hand, when the temperature of the processing liquid L is 70°C, the number of particles adhering to the substrate W may increase after gradually decreasing. When the temperature of the processing liquid L increases, as shown in FIG. 7(B), the eluate E elutes from the filter 26 into the processing liquid L, and it is considered that the eluate E adheres to the substrate W as particles. The higher the temperature of the processing liquid L, the easier it is for the eluate E to elute, and the more the number of particles adhering to the substrate W increases.

[0056] The eluate E is dissolved in the processing liquid L, for example, and after passing through the filter 26, it precipitates as particles on the substrate W. Alternatively, the eluate E is not dissolved in the processing liquid L but has a particle size that allows it to pass through the filter 26. In any case, as shown in FIG. 7(C), the eluate E passes through the filter 26. It is considered that as the circulation time becomes longer, the eluate E accumulates and the number of particles adhering to the substrate W increases.

[0057] Note that the device that generates the eluate E is not limited to the filter 26. Any device provided in the circulation line 21 may generate the eluate E in the processing liquid L. The relationship between the number of particles adhering to the substrate W, the circulation time, and the temperature of the processing liquid L varies depending on the composition of the processing liquid L and the material of the device.

[0058] In the present embodiment, as shown in FIG. 7(D), the processing liquid L contaminated with the eluate E is discharged, and instead, new processing liquid L is replenished into the tank 20. Thereby, it is possible to suppress the eluate E from adhering to the substrate W as particles and suppress an increase in particles due to the circulation of the processing liquid L.

[0059] Next, with reference to FIG. 8, an example of the processing of the calculation unit 104 and the second replenishment control unit 105 will be described. The processing after step S301 shown in FIG. 8 is performed in parallel with the processing after step S201 shown in FIG. 5 and is performed while circulating the processing liquid L.

[0060] First, the calculation unit 104 calculates a replenishment amount R for replenishing the tank 20 with the processing liquid L per set time t0 by the supply unit 50 (step S301). The set time t0 is, for example, 1 hour, but it may be 10 minutes. The set time t0 is appropriately changed. The replenishment amount R per set time t0 is hereinafter simply referred to as the replenishment amount R.

[0061] The replenishment of the processing liquid L is performed, for example, when the first determination unit 102 determines that the storage amount H is less than the lower limit value Hmin as shown in FIG. 5 (step S201, YES). The greater the consumption amount of the processing liquid L consumed by the processing unit 10, the more likely the storage amount H is to decrease, and the greater the replenishment amount R. The replenishment amount R is equivalent to the consumption amount.

[0062] When processing the substrate W, the processing unit 10 consumes the processing liquid L. Note that even while the processing of the substrate W is interrupted, the nozzle 16 periodically discharges the processing liquid L so that the processing liquid L does not stagnate around the nozzle 16 for a long time. Therefore, even while the processing of the substrate W is interrupted, the processing unit 10 consumes the processing liquid L.

[0063] However, during the period when the processing of the substrate W is interrupted, the consumption amount of the processing liquid L is less and the replenishment amount R is also less than during the period when the processing of the substrate W is executed. Also, the smaller the number of substrates W processed per set time t0, the smaller the consumption amount of the processing liquid L and the smaller the replenishment amount R. The replenishment amount R and the consumption amount vary according to the operating status of the substrate processing apparatus 1.

[0064] The calculation unit 104 calculates the replenishment amount R, for example, from the measurement value of the flow meter 52 provided in the supply line 51. In this case, the calculation unit 104 calculates the replenishment amount R by integrating the measurement value of the flow meter 52 over the set time t0.

[0065] The calculation unit 104 may receive a processing plan including the processing timing of the substrate W from the host computer 200 and calculate the replenishment amount R from the processing plan. The calculation unit 104 calculates the number of substrates W processed per set time t0 from the processing timing of the substrate W and calculates the consumption amount of the processing liquid L, thereby calculating the replenishment amount R.

[0066] The host computer 200 is provided outside the substrate processing apparatus 1 and transmits a processing plan to the substrate processing apparatus 1. The processing plan may include, in addition to the processing timing of the substrate W, the supply time of the processing liquid L to the substrate W and the supply flow rate of the processing liquid L to the substrate W. Note that the supply time and the supply flow rate may be read from those stored in advance in the control unit 90 and used.

[0067] Next, the second replenishment control unit 105 checks whether the calculated value of the replenishment amount R calculated by the calculation unit 104 is less than the set value R0 (step S302). The set value R0 is set such that the ratio of the eluate E in the processing liquid L is small and the number of particles adhering to the substrate W is equal to or less than the threshold value.

[0068] When the set value R0 becomes large to a certain extent, even if the set value R0 is increased, the number of particles adhering to the substrate W hardly decreases, and the amount of waste of the processing liquid L increases uselessly. Therefore, the set value R0 is set in consideration of the discharge amount in step S304.

[0069] When the calculated value of the replenishment amount R is equal to or greater than the set value R0 (step S302, NO), the replenishment amount R and the consumption amount are large, and the ratio of the eluate E in the processing liquid L is small. In this case, the second replenishment control unit 105 ends the current process.

[0070] On the other hand, when the calculated value of the replenishment amount R is less than the set value R0 (step S302, YES), the replenishment amount R and the consumption amount are small, and the ratio of the eluate E in the processing liquid L is large. In this case, the second replenishment control unit 105 determines the discharge amount for reducing the storage amount H of the tank 20 (step S303). The discharge amount is, for example, the same amount as the difference between the set value R0 and the calculated value.

[0071] Next, the second replenishment control unit 105 reduces the storage amount H of the tank 20 by the discharge unit 40 or the processing unit 10 (step S304). The second replenishment control unit 105 uses the first discharge unit 41 to reduce the storage amount H in a short time, but the second discharge unit 42 or the processing unit 10 may be used.

[0072] When the second replenishment control unit 105 reduces the storage amount H of the tank 20 to less than the lower limit value Hmin, the control by the first replenishment control unit 103 may be prohibited. Since the processing liquid L contaminated with the eluate E is discharged and then new processing liquid L is replenished, the discharge amount and the replenishment amount can be reduced compared to the case where discharge and replenishment are performed simultaneously.

[0073] Next, the second replenishment control unit 105 replenishes the tank 20 with a new processing liquid L by the supply unit 50 (step S305). The replenishment amount is, for example, the same amount as the discharge amount, and the same amount as the difference between the set value R0 and the calculated value. By this replenishment, the ratio of the eluate E in the processing liquid L decreases, and the number of particles adhering to the substrate W decreases.

[0074] Next, with reference to FIG. 9, an example of the result of the process of FIG. 8 will be described. In FIG. 9, the horizontal axis represents time, and the vertical axis represents the integrated value of the flow rate of the new processing liquid L replenished from the supply unit 50 to the tank 20. The integrated value is calculated every set time t0. The integrated value may be calculated using the flow meter 52, or may be calculated using the processing plan transmitted from the host computer 200.

[0075] When the replenishment amount R per set time t0 is less than the set value R0, steps S303 to S305 shown in FIG. 8 are performed, and a new processing liquid L is replenished from the supply unit 50 to the tank 20 as shown by the broken line in FIG. 9. On the other hand, when the replenishment amount R per set time t0 is equal to or greater than the set value R0, steps S303 to S305 shown in FIG. 8 are not performed.

[0076] Next, with reference to FIG. 10, an example of the relationship between the number of particles adhering to the substrate W, the circulation time, and the replenishment amount R will be described. The circulation time is the elapsed time from step S404 in FIG. 11 described later, and is the elapsed time from the completion of the liquid exchange process. Details of the liquid exchange process will be described later.

[0077] As shown in FIG. 10, while the actual value of the replenishment amount R is equal to the set value R0, the longer the circulation time, the more the filtration progresses, and the number of particles adhering to the substrate W decreases. After that, when the actual value of the replenishment amount R becomes zero, the longer the circulation time, the higher the ratio of the eluate E in the processing liquid L, and the number of particles adhering to the substrate W increases. From this, it can be seen that by controlling the replenishment amount R to be equal to or greater than the set value R0, an increase in particles due to the circulation of the processing liquid L can be suppressed.

[0078] Next, with reference to FIG. 11, an example of the processing of the second liquid exchange control unit 109 will be described. The processing after S401 shown in FIG. 11 is started when the second liquid exchange control unit 109 receives a liquid exchange command to exchange the processing liquid L in circulation. The liquid exchange command is transmitted, for example, from the host computer 200.

[0079] The processing liquid L in circulation exists, for example, in the tank 20, the circulation line 21, the devices 23 to 26 provided in the circulation line 21, the branch line 22, the devices 27 to 28 provided in the branch line 22, the reflux line 30, and the device 31 provided in the reflux line 30. The ratio of the volume of the processing liquid L in the tank 20 to the total volume of the processing liquid L in circulation is not particularly limited, but is, for example, 30% to 50%.

[0080] By periodically exchanging the processing liquid L, deterioration of the processing liquid L can be suppressed. An inert gas such as nitrogen gas is supplied to the upper space of the tank 20, but air can intrude. As moisture in the air gradually dissolves in the processing liquid L, the processing liquid L deteriorates. The moisture concentration of the new processing liquid L may be lower than the moisture concentration of the processing liquid L stored in the tank 20 and may be substantially zero.

[0081] First, when the second liquid exchange control unit 109 receives a liquid exchange command, it stops the pump 23 and stops the circulation of the processing liquid L (step S401). By stopping the pump 23, it is possible to prevent the pump 23 from running dry in the process of emptying the tank 20. The second liquid exchange control unit 109 may stop the heater 25 as well as stopping the pump 23. By stopping the circulation of the processing liquid L, it is possible to prevent a part of the processing liquid L from being concentratedly overheated.

[0082] Note that the processing by the second liquid exchange control unit 109 and the processing by the first liquid exchange control unit 108 described later are selectively executed. When the second liquid exchange control unit 109 receives a liquid exchange command and a command to prohibit the processing by the first liquid exchange control unit 108, it may start the processing after step S401.

[0083] Next, with the pump 23 stopped, the second liquid exchange control unit 109 reduces the storage amount H of the tank 20 by the discharge unit 40 (step S402). Since the circulation of the processing liquid L has stopped, the second liquid exchange control unit 109 uses the first discharge unit 41 instead of the second discharge unit 42 to reduce the storage amount H. As a result, the tank 20 becomes empty.

[0084] Next, the second liquid exchange control unit 109 supplies the processing liquid L to the tank 20 by the supply unit 50 (step S403).

[0085] Finally, the second liquid exchange control unit 109 restarts the pump 23 and resumes the circulation of the processing liquid L (step S404). The second liquid exchange control unit 109 may restart the heater 25 as well as restart the pump 23.

[0086] Note that the timing for restarting the pump 23 is after step S403 in this embodiment, but it may be after the storage amount H of the tank 20 exceeds a first threshold value H1 described later, or may be during step S403. The timing for restarting the heater 25 may be after the timing for restarting the pump 23, or may be simultaneous.

[0087] The first threshold value H1 is smaller than the lower limit value Hmin (H1 < Hmin). The first threshold value H1 is used for the determination by the second determination unit 106. The second determination unit 106 determines whether or not the storage amount H of the tank 20 is less than the first threshold value H1 during the circulation of the processing liquid L. For this determination, for example, the detector 61 shown in FIG. 1 is used.

[0088] When the second determination unit 106 determines that the storage amount H is less than the first threshold value H1, the forced stop unit 107 stops the pump 23. When an abnormality occurs during the circulation of the processing liquid L and the storage amount H decreases, it is possible to prevent the pump 23 from running dry and prevent the pump 23 from malfunctioning.

[0089] Incidentally, when the pump 23 is restarted, the number of particles P contained in the processing liquid L increases. The particles P are generated, for example, by the friction between the components constituting the pump 23. The particles P are also generated by being peeled off from the circulation line 21 or the devices 23 to 26 due to vibration. Further, when the heater 25 is restarted, the filter 26 thermally expands, and the particles P are detached from the filter 26. Therefore, the number of particles P increases immediately after the liquid exchange process.

[0090] On the other hand, unlike the second liquid exchange control unit 109, the first liquid exchange control unit 108 described later reduces the storage amount H of the tank 20 by the discharge unit 40 and supplies a new processing liquid L to the tank 20 by the supply unit 50 in a state where the processing liquid L is circulated by the pump 23. Since the pump 23 is not stopped, it is not restarted. Also, since the pump 23 is not stopped, the heater 25 is not stopped either. Therefore, an increase in the number of particles P immediately after the liquid exchange process can be suppressed.

[0091] Next, with reference to FIG. 12, an example of the process of the first liquid exchange control unit 108 will be described. The processes after S501 shown in FIG. 12 are started when the first liquid exchange control unit 108 receives a liquid exchange command. Note that the process by the first liquid exchange control unit 108 and the process by the second liquid exchange control unit 109 are selectively executed. The first liquid exchange control unit 108 may start the processes after step S501 when it receives a liquid exchange command and a command to prohibit the process by the second liquid exchange control unit 109.

[0092] When the first liquid exchange control unit 108 receives a liquid exchange command, it reduces the storage amount H of the tank 20 by the discharge unit 40 in a state where the processing liquid L is circulated by the pump 23 (step S501). Since the first liquid exchange control unit 108 continues to circulate the processing liquid L, it may continue to heat the processing liquid L by the heater 25.

[0093] When the first liquid exchange control unit 108 receives a liquid exchange command, with the processing liquid L being circulated by the pump 23, the discharge unit 40 may reduce the storage amount H of the tank 20 to the second threshold value H2. The second threshold value H2 is greater than the first threshold value H1 and less than the lower limit value Hmin (H1 < H2 < Hmin). The fact that the storage amount H has reached the second threshold value H2 is detected by the detector 62 shown in FIG. 1. Since the storage amount H is maintained at the first threshold value H1 or more, it is possible to prevent the pump 23 from being stopped by the forced stop unit 107.

[0094] Unlike the second liquid exchange control unit 109, the first liquid exchange control unit 108 may reduce the storage amount H of the tank 20 using the second discharge unit 42. Since the circulation of the processing liquid L is not stopped, the second discharge unit 42 can be used. Also, when using the second discharge unit 42, the processing liquid L can be surely made to flow through the circulation line 21 as compared with the case of using the first discharge unit 41.

[0095] Next, the first liquid exchange control unit 108 supplies the processing liquid L to the tank 20 by the supply unit 50 with the processing liquid L being circulated by the pump 23 (step S502). The storage amount H of the processing liquid L stored in the tank 20 is returned to be equal to or more than the lower limit value Hmin.

[0096] Next, the first liquid exchange control unit 108 checks whether steps S501 and S502 have been performed m times (step S503). m is a natural number of 1 or more, and is preset so that the ratio of the new processing liquid L to the total volume of the processing liquid L in circulation becomes a desired value or more. m can be changed as appropriate. m is preferably a natural number of 2 or more. The ratio of the new processing liquid L is the ratio of the new processing liquid L supplied after the start of step S501.

[0097] If the number of executions of steps S501 and S502 has not reached m times (step S503, NO), the first liquid exchange control unit 108 performs steps S501 and S502 again. On the other hand, if the number of executions of steps S501 and S502 has reached m times (step S503, YES), the first liquid exchange control unit 108 ends the current process.

[0098] Next, with reference to FIG. 13, an example of the relationship between the number of liquid exchanges and the ratio of fresh liquid will be described. The ratio of fresh liquid is the ratio of the new processing liquid L to the total volume of the processing liquid L in circulation. The number of liquid exchanges is the number of executions of steps S401 to S404 in FIG. 11 or the number of executions of steps S501 to S502 in FIG. 12. The ratio of the new processing liquid L is the ratio of the new processing liquid L supplied after the start of step S401 or step S501.

[0099] As the number of liquid exchanges increases, the ratio of fresh liquid increases. When performing the process of FIG. 12, since the discharge of the old processing liquid L and the supply of the new processing liquid L are carried out without stopping the circulation of the processing liquid L, the old processing liquid L and the new processing liquid L are mixed. Therefore, when performing the process of FIG. 12, the rate of increase in the ratio of fresh liquid is slower than when performing the process of FIG. 11. In order for the ratio of fresh liquid to be sufficiently high, m in FIG. 12 is preferably a natural number of 2 or more, and more preferably a natural number of 3 or more.

[0100] Next, with reference to FIG. 14, an example of the number of particles adhering to the substrate W immediately after liquid exchange will be described. The number of liquid exchanges was set so that the ratio of fresh liquid was substantially the same. As is clear from FIG. 14, when performing the liquid exchange of FIG. 12, since the circulation of the processing liquid is not stopped, the number of particles adhering to the substrate W could be suppressed to about 1 / 4 compared to when performing the liquid exchange of FIG. 11.

[0101] Next, with reference to FIG. 15, the substrate processing apparatus 1 according to the modified example will be described. Hereinafter, the differences will be mainly described. The substrate processing apparatus 1 of this modified example includes a filter 26 provided on the downstream side of the pump 23 in the circulation line 21, an on-off valve 71 provided on the downstream side of the filter 26 in the circulation line 21, and a processing liquid discharge unit 72 that discharges the processing liquid L from the middle between the filter 26 and the on-off valve 71 in the circulation line 21.

[0102] The processing liquid discharge unit 72 includes a discharge line 73 connected to the circulation line 21 between the filter 26 and the on-off valve 71, and an on-off valve 74 that opens and closes the discharge line 73. When the on-off valve 74 opens the discharge line 73, the discharge line 73 discharges the processing liquid L from the circulation line 21. On the other hand, when the on-off valve 74 closes the discharge line 73, the discharge line 73 stops discharging the processing liquid L from the circulation line 21.

[0103] The second liquid exchange control unit 109 (see FIG. 3) starts the pump 23 in step S404 after stopping the pump 23 in step S401 of FIG. 11. A high driving force is required to start the pump 23. The high driving force generates particles from the filter 26 and the like. The particles contaminate the circulation line 21. Once the circulation line 21 is contaminated with particles, a long time and a large amount of the processing liquid L are required for its purification.

[0104] Therefore, when starting the pump 23 after stopping the pump 23, the second liquid exchange control unit 109 closes the circulation line 21 with the on-off valve 71 and discharges the processing liquid L from the circulation line 21 with the processing liquid discharge unit 72. The particles generated when starting the pump 23 can be discharged to the discharge line 73, and contamination of the circulation line 21 can be suppressed. Therefore, the time required for filtration until restarting the processing of the substrate W can be shortened, and the usage amount of the processing liquid L can be reduced.

[0105] For example, when the elapsed time from the start of the pump 23 reaches the set time, the second liquid exchange control unit 109 opens the circulation line 21 with the on-off valve 71 and stops the discharge of the processing liquid L by the processing liquid discharge unit 72, and resumes the circulation of the processing liquid L (step S404 in FIG. 11). The set time is set in consideration of the time until the particles generated when starting the pump 23 reach the discharge line 73.

[0106] The on-off valve 71 and the processing liquid discharge part 72 are preferably provided on the upstream side of at least one connection point of the branch line 22 and the circulation line 21. Thereby, it is possible to suppress the contamination not only of the circulation line 21 but also of the branch line 22. It is more preferable that the on-off valve 71 and the processing liquid discharge part 72 are provided on the upstream side of all connection points of the branch line 22 and the circulation line 21.

[0107] As described above, the embodiments of the substrate processing apparatus and the substrate processing method according to the present disclosure have been described, but the present disclosure is not limited to the above embodiments. Within the scope described in the claims, various changes, modifications, substitutions, additions, deletions, and combinations are possible. Naturally, they also belong to the technical scope of the present disclosure.

Explanation of reference numerals

[0108] 1 Substrate processing apparatus 10 Processing unit 20 Tank 21 Circulation line 22 Branch line 40 Discharge part 50 Supply part 90 Control unit

Claims

1. A tank for storing a processing liquid, a circulation line for taking out the processing liquid from the tank and returning it to the tank, a branch line branching from the circulation line, a processing unit for supplying the processing liquid to a substrate at the tip of the branch line, a discharge unit for reducing the storage amount of the processing liquid stored in the tank, a supply unit for supplying new processing liquid to the tank, and a control unit for controlling the processing unit, the discharge unit, and the supply unit, wherein the control unit includes: a first determination unit for determining whether the storage amount of the processing liquid in the tank is less than a lower limit value; a first replenishment control unit for replenishing the tank with the processing liquid by the supply unit when the first determination unit determines that the storage amount is less than the lower limit value; a calculation unit for calculating a replenishment amount for replenishing the tank with the processing liquid per set time by the supply unit; a second replenishment control unit for reducing the storage amount of the tank by the discharge unit and replenishing the tank with the processing liquid by the supply unit when a calculated value of the replenishment amount calculated by the calculation unit is less than a set value; A substrate processing apparatus having the above components.

2. The supply unit includes a supply line connected to the tank and a flow meter for measuring the flow rate of the processing liquid passing through the supply line, The substrate processing apparatus according to claim 1, wherein the calculation unit calculates the replenishment amount from the measured value of the flow meter.

3. The substrate processing apparatus according to claim 2, wherein the calculation unit receives a processing plan including the processing timing of the substrate from an external host computer and calculates the replenishment amount from the processing plan and the measured value of the flow meter.

4. The substrate processing apparatus according to claim 1, wherein the calculation unit receives a processing plan including the processing timing of the substrate from an external host computer and calculates the replenishment amount from the processing plan.

5. The substrate processing apparatus according to any one of claims 1 to 4, wherein when the second replenishment control unit reduces the storage amount of the tank to less than the lower limit value, the processing by the first replenishment control unit is prohibited.

6. The substrate processing apparatus according to any one of claims 1 to 5, wherein the second replenishment control unit determines the amount by which the storage amount of the tank is to be reduced based on the difference between the calculated value of the replenishment amount and the set value.

7. When the calculated value of the replenishment amount is greater than or equal to the set value, the second replenishment control unit neither reduces the storage amount of the tank by the discharge unit nor replenishes the processing liquid into the tank by the supply unit. The substrate processing apparatus according to any one of claims 1 to 6.

8. The discharge unit includes a first discharge line connected to the tank and a first on-off valve for opening and closing the first discharge line, and a first discharge unit; a second discharge line connected to the circulation line and a second on-off valve for opening and closing the second discharge line, and a second discharge unit; The substrate processing apparatus according to any one of claims 1 to 7, including at least one of them.

9. A tank for storing a processing liquid, a circulation line for taking out the processing liquid from the tank and returning it to the tank, a pump provided in the circulation line, a branch line branched from the circulation line, a processing unit for supplying the processing liquid to a substrate at the end of the branch line, a discharge unit for reducing the storage amount of the processing liquid stored in the tank, a supply unit for supplying new processing liquid to the tank, and a control unit for controlling the pump, the processing unit, the discharge unit, and the supply unit. When receiving a liquid exchange command for exchanging the processing liquid during circulation, the control unit has a first liquid exchange control unit that reduces the storage amount of the tank by the discharge unit and supplies the processing liquid to the tank by the supply unit while circulating the processing liquid by the pump. The substrate processing apparatus.

10. Comprising a heater provided in the circulation line, When receiving the liquid exchange command, the first liquid exchange control unit reduces the storage amount of the tank by the discharge unit and supplies the processing liquid to the tank by the supply unit while heating the processing liquid by the heater. The substrate processing apparatus according to claim 9.

11. The control unit has a second determination unit for determining whether or not the storage amount of the tank is less than a first threshold value, and a forced stop unit for stopping the pump when the second determination unit determines that the storage amount is less than the first threshold value. When the first liquid exchange control unit receives the liquid exchange command, while circulating the processing liquid by the pump, the discharge unit reduces the storage amount of the tank to a second threshold value greater than the first threshold value and the supply unit supplies the processing liquid to the tank. The substrate processing apparatus according to claim 9 or 10.

12. The first liquid exchange control unit repeatedly performs, a plurality of times, reducing the storage amount of the tank to the second threshold value by the discharge unit and supplying the processing liquid to the tank by the supply unit while circulating the processing liquid by the pump. The substrate processing apparatus according to claim 11.

13. When the control unit receives the liquid exchange command and a command for prohibiting the processing by the first liquid exchange control unit, the control unit has a second liquid exchange control unit that, with the pump stopped, reduces the storage amount of the tank by the discharge unit and supplies the processing liquid to the tank by the supply unit. The substrate processing apparatus according to any one of claims 9 to 12.

14. A filter provided downstream of the pump in the circulation line, an on-off valve provided downstream of the filter in the circulation line, and a processing liquid discharge unit that discharges the processing liquid from the middle of the filter and the on-off valve in the circulation line. After stopping the pump, when starting the pump, the second liquid exchange control unit closes the circulation line by the on-off valve and discharges the processing liquid from the circulation line by the processing liquid discharge unit. The substrate processing apparatus according to claim 13.

15. A substrate processing method including circulating a processing liquid from a tank through a circulation line back to the tank, and supplying the processing liquid to a substrate at the tip of a branch line branching from the circulation line. Determining whether the storage amount of the processing liquid in the tank is less than a lower limit value. When it is determined that the storage amount is less than the lower limit value, replenishing the tank with new processing liquid. Calculating a replenishment amount for replenishing the tank with new processing liquid per set time. When the calculated value of the replenishment amount is less than a set value, reducing the storage amount of the tank and replenishing the tank with new processing liquid. A substrate processing method comprising the above steps.

16. A substrate processing method comprising circulating a processing liquid from a tank through a circulation line back to the tank, and supplying the processing liquid to a substrate at the end of a branch line branched from the circulation line. A substrate processing method, when receiving a liquid exchange command for exchanging the processing liquid during circulation, reducing the storage amount of the processing liquid in the tank while circulating the processing liquid, and supplying new processing liquid to the tank.

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