Substrate processing method and substrate processing apparatus

Abstract

To provide a technology capable of facilitating maintaining the concentration of an evaporation component contained in process liquid.SOLUTION: A substrate processing method according to the present disclosure is a substrate processing method for processing a substrate by immersing the substrate in process liquid containing an evaporation component and includes a periodic supplement step, a measurement step, and a feedback supplement step. In the periodic supplement step, the evaporation component is supplemented in a first supplement amount and at a first time interval so that the concentration of the evaporation component in the process liquid falls within an allowable range. In the measurement step, the concentration is measured. In the feedback supplement step, a determination whether or not the concentration measured in the measurement step falls below a threshold is executed at a second time interval and the evaporation component is supplemented in a second supplement amount when it is determined that the concentration falls below the threshold. In the substrate processing method according to the present disclosure, the periodic supplement step and the feedback supplement step are performed in parallel.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] Conventionally, a technique of processing a substrate by immersing the substrate in a processing liquid stored in a processing tank has been known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a technique capable of facilitating the maintenance of the concentration of evaporation components contained in a processing liquid.

Means for Solving the Problems

[0005] A substrate processing method according to an aspect of the present disclosure is a substrate processing method for processing a substrate by immersing the substrate in a processing liquid containing evaporation components, including a regular replenishment step, a measurement step, and a feedback replenishment step. The regular replenishment step replenishes evaporation components at a first replenishment amount and at a first time interval so that the concentration of evaporation components in the processing liquid remains within an allowable range. The measurement step measures the concentration. The feedback replenishment step determines whether or not the concentration measured in the measurement step is lower than a threshold value at a second time interval, and when it is determined that the concentration is lower than the threshold value, replenishes evaporation components at a second replenishment amount. Further, in the substrate processing method according to an aspect of the present disclosure, the regular replenishment step and the feedback replenishment step are performed in parallel.

Effects of the Invention

[0006] According to the present disclosure, it is possible to facilitate maintaining the concentration of the evaporation component contained in the processing liquid.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments for implementing a substrate processing method and a substrate processing apparatus according to the present disclosure (hereinafter referred to as "embodiments") will be described in detail with reference to the drawings. Note that the present disclosure is not limited by these embodiments. Also, the respective embodiments can be appropriately combined within a range where the processing contents do not conflict. In addition, in the following embodiments, the same reference numerals are assigned to the same parts, and redundant explanations are omitted.

[0009] In addition, in the following embodiments, expressions such as "constant", "orthogonal", "perpendicular", or "parallel" may be used, but these expressions do not necessarily require strict "constant", "orthogonal", "perpendicular", or "parallel". That is, each of the above expressions is assumed to allow deviations such as manufacturing accuracy and installation accuracy.

[0010] In addition, in each of the drawings referred to below, in order to make the explanation easier to understand, an orthogonal coordinate system may be shown that defines the X-axis direction, the Y-axis direction, and the Z-axis direction that are orthogonal to each other, with the positive Z-axis direction being the vertically upward direction. Also, the rotation direction around the vertical axis may be referred to as the θ direction.

[0011] Conventionally, a technique is known in which a plurality of substrates are processed collectively by immersing the plurality of substrates in a processing liquid stored in a processing tank.

[0012] In recent years, for the purpose of improving throughput, for example, the processing tank has a tendency to increase in size so that more substrates can be processed collectively.

[0013] When the processing tank increases in size, the opening of the processing tank becomes larger, and accordingly, the evaporation area becomes larger. Therefore, the evaporation rate of the evaporation components contained in the processing liquid becomes faster. That is, when the processing tank increases in size, the concentration decrease of the evaporation components in the processing liquid becomes faster.

[0014] In addition, when the processing liquid increases in size, the amount of the processing liquid stored in the processing tank increases. For this reason, it takes a long time for the concentration of the evaporation component in the processing liquid to stabilize after replenishing the evaporation component. That is, the concentration responsiveness of the evaporation component decreases.

[0015] In such a situation, hunting of the concentration of the evaporation component becomes large (the amplitude becomes large), so there is a possibility that it becomes difficult to maintain the concentration of the evaporation component.

[0016] Note that the factors that make it difficult to maintain the concentration of the evaporation component are not limited to the enlargement of the processing tank described above. For example, while the processing liquid is being sampled and sent to the concentration monitor, the evaporation component in the processing tank evaporates, resulting in a deviation between the concentration measured by the concentration monitor and the concentration in the processing tank. Further, when sampling a high-temperature processing liquid, it is necessary to temporarily cool the sampled processing liquid before measuring the concentration with the concentration monitor. In this case, the deviation between the concentration measured by the concentration monitor and the concentration in the processing tank becomes large. These points can also be factors that make it difficult to maintain the concentration of the evaporation component.

[0017] Therefore, a technique that can facilitate the maintenance of the concentration of the evaporation component contained in the processing liquid is expected.

[0018] <Configuration of Substrate Processing Apparatus> First, the configuration of the substrate processing apparatus according to the embodiment will be described with reference to FIG. 1. FIG. 1 is a block diagram showing the configuration of the substrate processing apparatus according to the embodiment.

[0019] As shown in FIG. 1, the substrate processing apparatus 1 according to the embodiment includes a liquid processing unit 2, a processing liquid supply system 3, and a control device 4.

[0020] The liquid processing unit 2 processes a substrate such as a semiconductor wafer (hereinafter referred to as "wafer") using a processing liquid.

[0021] The processing liquid contains volatile components. As an example, the processing liquid according to the embodiment is SC1 (aqueous ammonia / hydrogen peroxide solution). SC1 contains ammonia as a volatile component. As an example, the liquid processing unit 2 etches and removes a silicon-based film (for example, a polysilicon film, a silicon oxide film, and a SiN film, etc.) formed on a wafer by supplying SC1 to the wafer. A configuration example of the liquid processing unit 2 will be described later.

[0022] In this embodiment, the case where the processing liquid is SC1 is taken as an example for description. However, the processing liquid may be any liquid that contains at least volatile components and is not limited to SC1. For example, the processing liquid may be ammonium hydroxide diluted to a predetermined concentration (dilute aqueous ammonia), BHF (buffered hydrofluoric acid: a mixture of hydrofluoric acid and ammonium fluoride solution), etc. These also contain ammonia as a volatile component.

[0023] Also, the processing liquid may contain volatile components other than ammonia. For example, the processing liquid may be SC1 containing hydrogen peroxide as a volatile component, SC2 (a mixture of hydrochloric acid, hydrogen peroxide, and water), SPM (a mixture of sulfuric acid, hydrogen peroxide, and water), etc. Also, the processing liquid may be fluonitric acid (a mixture of hydrofluoric acid and nitric acid) containing nitric acid as a volatile component, PAN (a mixture of phosphoric acid, acetic acid, and nitric acid), etc. Also, the processing liquid may be an aqueous phosphoric acid solution containing water as a volatile component. The aqueous phosphoric acid solution may be used at a temperature of 100 degrees or higher, for example. In such a case, the water contained in the aqueous phosphoric acid solution becomes a volatile component.

[0024] The processing liquid supply system 3 supplies or replenishes the above processing liquid to the liquid processing unit 2. A configuration example of the processing liquid supply system 3 will be described later.

[0025] The control device 4 controls the liquid processing unit 2 and the processing liquid supply system 3. The control device 4 is, for example, a computer, and includes a control unit 41 and a storage unit 42. Programs for controlling various processes executed in the substrate processing apparatus 1 are stored in the storage unit 42. The control unit 41 controls the operations of the liquid processing unit 2 and the processing liquid supply system 3 by reading and executing the programs stored in the storage unit 42.

[0026] Note that such programs may be recorded on a computer-readable storage medium and installed from the storage medium into the storage unit 42 of the control device 4. Examples of computer-readable storage media include hard disks (HD), flexible disks (FD), compact disks (CD), magneto-optical disks (MO), memory cards, and the like.

[0027] The number of liquid processing units 2 provided in the substrate processing apparatus 1 is not limited to one. That is, the substrate processing apparatus 1 may include a plurality of liquid processing units 2. In this case, the substrate processing apparatus 1 may include a plurality of processing liquid supply systems 3 corresponding to the plurality of liquid processing units 2, or may include one processing liquid supply system 3 corresponding to the plurality of liquid processing units 2.

[0028] <Configuration of the Liquid Processing Unit> Next, a configuration example of the liquid processing unit 2 will be described with reference to FIG. 2. FIG. 2 is a diagram showing the configuration of the liquid processing unit 2 according to the embodiment.

[0029] The liquid processing unit 2 shown in FIG. 2 is a batch-type processing unit that processes a plurality of wafers W (only one is shown in FIG. 2) collectively. As shown in FIG. 2, the liquid processing unit 2 includes a processing tank 21, a holding unit 22, and a plurality of discharge units 23. Note that the number of discharge units 23 provided in the liquid processing unit 2 is not limited to three.

[0030] The processing tank 21 includes an inner tank 211 and an outer tank 212. The inner tank 211 is a box-shaped tank having an opening at the upper part, and stores a processing liquid inside. The inner tank 211 can accommodate a plurality of wafers W therein. A lot formed by the plurality of wafers W is immersed in such an inner tank 211. The outer tank 212 is disposed so as to surround the inner tank 211 on the outside of the inner tank 211. The outer tank 212 has an opening at the upper part. Then, the processing liquid that has overflowed from the inner tank 211 flows into the outer tank 212.

[0031] The holding unit 22 holds a plurality of wafers W forming a lot in a vertical posture. The holding unit 22 has a lifting mechanism (not shown) for lifting and lowering the held lot, and lowers the lot from above the inner tank 211 in the processing tank 21 to immerse it in the inner tank 211, or raises the lot immersed in the inner tank 211 to take it out of the processing tank 21.

[0032] The plurality of discharge units 23 are disposed inside the inner tank 211, specifically, near the bottom of the inner tank 211. The plurality of discharge units 23 are connected to the processing liquid supply system 3, and discharge the processing liquid supplied from the processing liquid supply system 3 into the inner tank 211.

[0033] The liquid processing unit 2 holds a lot using the holding unit 22, and immerses the held lot in the processing liquid stored in the inner tank 211. Thereby, the plurality of wafers W are processed by the processing liquid. For example, in the embodiment, the silicon-based film on the plurality of wafers W is etched and removed by SC1 which is the processing liquid.

[0034] <Configuration of the processing liquid supply system> Next, a configuration example of the processing liquid supply system 3 will be described with reference to FIG. 3. FIG. 3 is a diagram showing the configuration of the processing liquid supply system 3 according to the embodiment.

[0035] As shown in FIG. 3, the processing liquid supply system 3 includes a circulation unit 30, a periodic replenishment unit 31, and a feedback replenishment unit 32.

[0036] The circulation unit 30 includes a circulation line 301, a pump 302, a heater 303, a filter 304, an ammonia concentration meter 306, and a hydrogen peroxide concentration meter 308.

[0037] The circulation line 301 is a flow path that allows the processing liquid to flow out of the processing tank 21 and return to the processing tank 21. For example, one end of the circulation line 301 is connected to the bottom of the outer tank 212 in the processing tank 21, and the other end is connected to a plurality of discharge parts 23 arranged inside the inner tank 211. In this way, the circulation line 301 circulates the processing liquid between the inner tank 211 and the outer tank 212.

[0038] The pump 302, the heater 303, the filter 304, the ammonia concentration meter 306, and the hydrogen peroxide concentration meter 308 are provided in the middle part of the circulation line 301.

[0039] The pump 302 sends out the processing liquid in the outer tank 212 to the circulation line 301. The heater 303 heats the processing liquid flowing through the circulation line 301. Note that the processing tank 21 may be provided with a temperature measurement unit for measuring the temperature of the processing liquid in the processing tank 21. In this case, the control unit 41 (see FIG. 1) controls the heater 303 to heat the processing liquid flowing through the circulation line 301 based on the measurement result by the temperature measurement unit so as to keep the temperature of the processing liquid in the processing tank 21 at a desired temperature. Thereby, the processing liquid supply system 3 can maintain the temperature of the processing liquid at a specified value. The filter 304 removes impurities from the processing liquid flowing through the circulation line 301.

[0040] The ammonia concentration meter 306 measures the ammonia concentration in the processing liquid. The ammonia concentration meter 306 is provided on a sampling line 306a. The sampling line 306a is a line that branches off from the circulation line 301 and returns to the circulation line 301. The measurement result by the ammonia concentration meter 306 is input to the control unit 41.

[0041] The hydrogen peroxide concentration meter 308 measures the hydrogen peroxide concentration in the treatment liquid. The hydrogen peroxide concentration meter 308 is provided in the sampling line 308a. The sampling line 308a is a line that branches from the circulation line 301 and returns to the circulation line 301. The measurement result by the hydrogen peroxide concentration meter 308 is input to the control unit 41.

[0042] The circulation unit 30 sends the treatment liquid from the outer tank 212 to the circulation line 301 using the pump 302. The treatment liquid sent to the circulation line 301 is supplied into the inner tank 211 from the discharge part 23 through the circulation line 301. The treatment liquid supplied to the inner tank 211 overflows from the inner tank 211 and flows out to the outer tank 212. In this way, the treatment liquid circulates between the inner tank 211 and the outer tank 212.

[0043] When the outer tank 212 is defined as the most upstream and the inner tank 211 is defined as the most downstream, the pump 302, the heater 303, the filter 304, the ammonia concentration meter 306, and the hydrogen peroxide concentration meter 308 are provided in this order from the upstream side.

[0044] The regular replenishment unit 31 replenishes the treatment tank 21 with ammonia water. Specifically, the regular replenishment unit 31 includes an ammonia water supply source 311, a replenishment line 312, and a flow regulator 313. The ammonia water supply source 311 supplies a solution containing ammonia as an evaporation component (here, ammonia water). The replenishment line 312 connects the ammonia water supply source 311 and the outer tank 212, and supplies ammonia water from the ammonia water supply source 311 to the outer tank 212. The flow regulator 313 is provided in the replenishment line 312 and adjusts the supply amount of the ammonia water supplied to the outer tank 212. The flow regulator 313 is composed of, for example, an on-off valve, a flow control valve, a flow meter, etc.

[0045] In addition, the regular replenishment unit 31 replenishes the treatment tank 21 with hydrogen peroxide water. Specifically, the regular replenishment unit 31 includes a hydrogen peroxide water supply source 351, a replenishment line 352, and a flow rate adjuster 353. The hydrogen peroxide water supply source 351 supplies a solution containing O2, which is a decomposition component (here, hydrogen peroxide water). The replenishment line 352 connects the hydrogen peroxide water supply source 351 and the outer tank 212, and supplies hydrogen peroxide water from the hydrogen peroxide water supply source 351 to the outer tank 212. The flow rate adjuster 353 is provided in the replenishment line 352 and adjusts the supply amount of the hydrogen peroxide water supplied to the outer tank 212. The flow rate adjuster 353 is composed of, for example, an on-off valve, a flow control valve, a flow meter, etc.

[0046] The feedback replenishment unit 32 replenishes the treatment tank 21 with ammonia water. Specifically, the feedback replenishment unit 32 includes an ammonia water supply source 321, a replenishment line 322, and a flow rate adjuster 323. The ammonia water supply source 321 supplies a solution containing ammonia, which is an evaporation component (here, ammonia water). The replenishment line 322 connects the ammonia water supply source 321 and the outer tank 212, and supplies ammonia water from the ammonia water supply source 321 to the outer tank 212. The flow rate adjuster 323 is provided in the replenishment line 322 and adjusts the supply amount of the ammonia water supplied to the outer tank 212. The flow rate adjuster 323 is composed of, for example, an on-off valve, a flow control valve, a flow meter, etc.

[0047] In addition, the feedback replenishment unit 32 replenishes the treatment tank 21 with hydrogen peroxide water. Specifically, the feedback replenishment unit 32 includes a hydrogen peroxide water supply source 341, a replenishment line 342, and a flow rate adjuster 343. The hydrogen peroxide water supply source 341 supplies a solution containing O2, which is a decomposition component (here, hydrogen peroxide water). The replenishment line 342 connects the hydrogen peroxide water supply source 341 and the outer tank 212, and supplies hydrogen peroxide water from the hydrogen peroxide water supply source 341 to the outer tank 212. The flow rate adjuster 343 is provided in the replenishment line 342 and adjusts the supply amount of the hydrogen peroxide water supplied to the outer tank 212. The flow rate adjuster 343 is composed of, for example, an on-off valve, a flow control valve, a flow meter, etc.

[0048] The regular replenishment unit 31 and the feedback replenishment unit 32 supply a replenishing liquid (ammonia water or hydrogen peroxide water) to the outer tank 212 of the treatment tank 21. With such a configuration, since the replenishing liquid can be efficiently mixed with the treatment liquid by utilizing the flow of the treatment liquid by the circulation unit 30, the ammonia concentration (or hydrogen peroxide concentration) in the treatment liquid can be stabilized at an early stage. Note that the present invention is not limited to this, and the regular replenishment unit 31 and the feedback replenishment unit 32 may supply the replenishing liquid to, for example, the circulation line 301 or the inner tank 211.

[0049] The control unit 41 (see FIG. 1) controls the regular replenishment unit 31 and the feedback replenishment unit 32 to replenish ammonia water or hydrogen peroxide water.

[0050] Specifically, the control unit 41 controls the regular replenishment unit 31 to perform a regular replenishment process. The regular replenishment process is a process of replenishing a replenishing liquid in a specified replenishment amount at a specified replenishment interval so that the component concentration (here, ammonia concentration) in the treatment liquid falls within an allowable range.

[0051] In addition, the control unit 41 controls the feedback replenishment unit 32 to perform a feedback replenishment process. The feedback replenishment process determines whether or not the concentration measured by the ammonia concentration meter 306 or the hydrogen peroxide concentration meter 308 is lower than a threshold value (FB threshold value) at a specified determination interval. Then, when it is determined that the measured concentration is lower than the FB threshold value, a replenishing liquid in a specified replenishment amount is replenished.

[0052] In the substrate processing apparatus 1 according to the embodiment, the control unit 41 performs the regular replenishment process and the feedback replenishment process in parallel as the replenishment process of ammonia, which is an evaporation component. Hereinafter, this point will be specifically described.

[0053] FIG. 4 is a diagram showing an example of the concentration management information stored in the storage unit 42 according to the embodiment. As shown in FIG. 4, the concentration management information is information in which a "target concentration", a "permissible concentration range", and an "FB threshold value" are associated for each target component (here, ammonia and hydrogen peroxide) in the processing liquid.

[0054] In the "target concentration" item, information indicating the target value of the concentration is stored. For example, in the example shown in FIG. 4, the target concentration of ammonia is "1 wt%", and the target concentration of hydrogen peroxide is "5 wt%".

[0055] In the "permissible range" item, information indicating the permissible range of the concentration is stored. The "permissible range" item includes an "upper limit concentration" item and a "lower limit concentration" item. In the "upper limit concentration" item, information indicating the upper limit value of the permissible range of the concentration is stored, and in the "lower limit concentration" item, information indicating the lower limit value of the permissible range of the concentration is stored. Note that the concentration value stored in the "upper limit concentration" item is higher than the concentration value stored in the "target concentration" item, and the concentration value stored in the "lower limit concentration" item is lower than the concentration value stored in the "target concentration" item. For example, in the example shown in FIG. 4, the permissible range of the ammonia concentration is "0.9 wt% or more and 1.1 wt% or less", and the permissible range of the hydrogen peroxide concentration is "4.5 wt% or more and 5.5 wt% or less".

[0056] In the "FB threshold value" item, the threshold value used for the feedback replenishment process is stored. The concentration value stored in the "FB threshold value" item is lower than the concentration value stored in the "target concentration" item and higher than the concentration value stored in the "lower limit concentration" item. For example, in the example shown in FIG. 4, the FB threshold value for the feedback replenishment process for ammonia is "0.95 wt%", and the FB threshold value for the feedback replenishment process for hydrogen peroxide is "4.95 wt%".

[0057] FIG. 5 is a diagram showing an example of replenishment mode information stored in the storage unit 42 according to the embodiment. As shown in FIG. 5, the replenishment mode information is information in which the "first replenishment mode", the "second replenishment mode", and the "third replenishment mode" are associated with each target component (here, ammonia and hydrogen peroxide) in the processing liquid.

[0058] The "first replenishment mode" item, the "second replenishment mode" item, and the "third replenishment mode" item each include a "regular replenishment process" item and a "feedback replenishment process" item. Further, each "regular replenishment process" item includes a "replenishment interval" item and a "replenishment amount" item, and each "feedback replenishment process" item includes a "determination interval" item and a "replenishment amount" item.

[0059] In the "replenishment interval" item of the "regular replenishment process" item, information indicating the time interval for replenishing the replenishment liquid (here, aqueous ammonia) is stored. Further, in the "replenishment amount" item of the "regular replenishment process" item, information indicating the replenishment amount of the replenishment liquid is stored.

[0060] For example, in the first replenishment mode, the regular replenishment process for ammonia is executed at a replenishment interval of 100 sec (first time interval) and a replenishment amount of 50 ml (first replenishment amount). Also, in the second replenishment mode, the regular replenishment process for ammonia is executed at a replenishment interval of 50 sec (third time interval) and a replenishment amount of 100 ml (third replenishment amount). Further, in the third replenishment mode, the regular replenishment process for ammonia is executed at a replenishment interval of 150 sec (fifth time interval) and a replenishment amount of 20 ml (fifth replenishment amount).

[0061] In the substrate processing apparatus 1 according to the embodiment, the periodic replenishment process for hydrogen peroxide is not performed. Therefore, no information is stored in the "periodic replenishment process" item corresponding to hydrogen peroxide (or "null" may be stored). Note that the substrate processing apparatus 1 may perform a periodic replenishment process for hydrogen peroxide. In this case, a numerical value will be stored in the "periodic replenishment process" item corresponding to hydrogen peroxide. The periodic replenishment process for hydrogen peroxide is performed using the hydrogen peroxide water supply source 351, the replenishment line 352, and the flow regulator 353.

[0062] In the "determination interval" item of the "feedback replenishment process" item, information indicating the execution interval of the determination process for determining whether the concentration measured by the ammonia concentration meter 306 or the hydrogen peroxide concentration meter 308 is below the FB threshold value is stored. Also, in the "replenishment amount" item of the "feedback replenishment process" item, information indicating the replenishment amount of the replenishment liquid is stored. Note that the replenishment amount stored in the "replenishment amount" item of the "feedback replenishment process" item is less than the replenishment amount stored in the "replenishment amount" item of the "periodic replenishment process" item.

[0063] For example, in the first replenishment mode, the feedback replenishment process for ammonia is executed at a determination interval of 30 sec (the second time interval) and a replenishment amount of 30 ml (the second replenishment amount). Also, in the second replenishment mode, the feedback replenishment process for ammonia is executed at a determination interval of 15 sec (the fourth time interval) and a replenishment amount of 60 ml (the fourth replenishment amount). Also, in the third replenishment mode, the feedback replenishment process for ammonia is executed at a replenishment interval of 120 sec (the sixth time interval) and a replenishment amount of 5 ml (the sixth replenishment amount).

[0064] Also, in the example shown in FIG. 5, each numerical value of the feedback replenishment process for hydrogen peroxide is the same as each numerical value of the feedback replenishment process for ammonia. Note that the present invention is not limited to this, and each numerical value of the feedback replenishment process for hydrogen peroxide may be different from each numerical value of the feedback replenishment process for ammonia.

[0065] FIG. 6 is a diagram summarizing the relationships of the replenishment intervals, determination intervals, and replenishment amounts among the first replenishment mode, the second replenishment mode, and the third replenishment mode according to the embodiment. As shown in FIG. 6, the replenishment interval (the third time interval) and the determination interval (the fourth time interval) in the second replenishment mode are set shorter than the replenishment interval (the first time interval) and the determination interval (the second time interval) in the first replenishment mode. Also, the replenishment amounts (the third replenishment amount and the fourth replenishment amount) in the second replenishment mode are set larger than the replenishment amounts (the first replenishment amount and the second replenishment amount) in the first replenishment mode.

[0066] Also, the replenishment interval (the fifth time interval) and the determination interval (the sixth time interval) in the third replenishment mode are set longer than the replenishment interval (the first time interval) and the determination interval (the second time interval) in the first replenishment mode. Also, the replenishment amounts (the fifth replenishment amount and the sixth replenishment amount) in the third replenishment mode are set smaller than the replenishment amounts (the first replenishment amount and the second replenishment amount) in the first replenishment mode.

[0067] <Procedure of replenishment process> Next, the procedure of the replenishment process will be described. First, the procedures of the regular replenishment process and the feedback replenishment process will be described with reference to FIGS. 7 and 8. FIG. 7 is a flowchart showing the procedure of the regular replenishment process according to the embodiment. Also, FIG. 8 is a flowchart showing the procedure of the feedback replenishment process according to the embodiment. Each flowchart shown in FIGS. 7 and 8 is executed according to the control by the control unit 41.

[0068] First, the procedure of the regular replenishment process will be described. As shown in FIG. 7, the control unit 41 controls the regular replenishment unit 31 to replenish a specified amount of aqueous ammonia into the outer tank 212 of the treatment tank 21 (step S101). Specifically, the control unit 41 replenishes the replenishing liquid (here, aqueous ammonia) in accordance with the replenishment amount corresponding to the current replenishment mode. For example, when the current replenishment mode is the first replenishment mode, the control unit 41 controls the regular replenishment unit 31 to replenish 50 ml of aqueous ammonia as the specified amount into the outer tank 212 (see FIG. 5). Also, when the current replenishment mode is the second replenishment mode, the control unit 41 controls the regular replenishment unit 31 to replenish 100 ml of aqueous ammonia as the specified amount into the outer tank 212.

[0069] Subsequently, the control unit 41 determines whether or not a specified time has elapsed since the replenishment of the aqueous ammonia in step S101 (step S102). Specifically, the control unit 41 determines whether or not the replenishment interval corresponding to the current replenishment mode has elapsed. For example, when the current replenishment mode is the first replenishment mode, the control unit 41 determines whether or not 100 seconds have elapsed since the replenishment in step S101.

[0070] In step S102, when the specified time has not elapsed (step S102, No), the control unit 41 repeats the determination process of step S102 until the specified time elapses. On the other hand, in step S102, when it is determined that the specified time has elapsed (step S102, Yes), the control unit 41 returns the process to step S101 and replenishes the specified amount of aqueous ammonia again.

[0071] Next, the procedure of the feedback replenishment process will be described. Here, the feedback replenishment process for aqueous ammonia will be described as an example, and the description of the feedback replenishment process for hydrogen peroxide water will be omitted. Note that the feedback replenishment process for hydrogen peroxide water is also performed in the same procedure as the flowchart shown in FIG. 8.

[0072] As shown in FIG. 8, the control unit 41 first acquires the concentration value (step S201). Specifically, the control unit 41 acquires the value of the ammonia concentration measured by the ammonia concentration meter 306.

[0073] Subsequently, the control unit 41 determines whether the acquired concentration value is below the FB threshold (step S202). For example, when the FB threshold corresponding to ammonia is "0.95 wt%" (see FIG. 4), the control unit 41 determines whether the concentration value acquired in step S201 is below 0.95 wt%.

[0074] If it is determined in step S202 that the concentration value is below the FB threshold (step S202, Yes), the control unit 41 controls the feedback replenishment unit 32 to replenish a specified amount of aqueous ammonia (step S203). Specifically, the control unit 41 replenishes the aqueous ammonia in accordance with the replenishment amount corresponding to the current replenishment mode. For example, when the current replenishment mode is the first replenishment mode, the control unit 41 controls the feedback replenishment unit 32 to replenish 30 ml of aqueous ammonia as the specified amount into the outer tank 212 (see FIG. 5). Also, when the current replenishment mode is the second replenishment mode, the control unit 41 controls the feedback replenishment unit 32 to replenish 60 ml of aqueous ammonia as the specified amount into the outer tank 212.

[0075] When the process of step S203 is completed or when the concentration value is not below the FB threshold in step S202 (step S202, No), the control unit 41 determines whether a specified time has elapsed since the determination process of step S202 was performed (step S204). Specifically, the control unit 41 determines whether the determination interval corresponding to the current replenishment mode has elapsed. For example, when the current replenishment mode is the first replenishment mode, the control unit 41 determines whether 30 seconds have elapsed since the determination process of step S202 was performed.

[0076] In step S204, if the specified time has not elapsed (step S204, No), the control unit 41 repeats the determination process in step S204 until the specified time elapses. On the other hand, in step S204, if it is determined that the specified time has elapsed (step S204, Yes), the control unit 41 returns the process to step S201 and acquires again the value of the ammonia concentration measured by the ammonia concentration meter 306.

[0077] Here, it is assumed that the specified time determined in step S204 is the elapsed time since the determination process in step S202 was performed, but this is synonymous with the elapsed time since the concentration value was acquired in step S201. That is, the control unit 41 may determine in step S204 whether or not the specified time has elapsed since the concentration value was acquired in step S201.

[0078] Next, the procedure of the mode change process will be described with reference to FIG. 9. FIG. 9 is a flowchart showing the procedure of the mode change process according to the embodiment. Each flowchart shown in FIG. 9 is executed according to the control by the control unit 41. Here, the mode change process for aqueous ammonia will be described as an example, and the description of the mode change process for aqueous hydrogen peroxide will be omitted. Note that the mode change process for aqueous hydrogen peroxide is performed in the same procedure as the flowchart shown in FIG. 9 and independently of the mode change process for aqueous ammonia. That is, for example, the replenishment mode is set independently for each of aqueous ammonia and aqueous hydrogen peroxide.

[0079] As shown in FIG. 9, the control unit 41 acquires a concentration value (step S301). Specifically, the control unit 41 acquires the value of the ammonia concentration measured by the ammonia concentration meter 306. Subsequently, the control unit 41 determines whether or not the acquired concentration value is within the allowable range (step S302). For example, when the allowable range corresponding to ammonia is 0.9 wt% or more and 1.1 wt% or less (see FIG. 4), the control unit 41 determines whether or not the concentration value acquired in step S301 is 0.9 wt% or more and 1.1 wt% or less.

[0080] In step S302, when it is determined that the concentration value is within the allowable range (step S302, Yes), the control unit 41 sets the current replenishment mode to the first replenishment mode (step S303).

[0081] On the other hand, in step S302, when the concentration value is not within the allowable range (step S302, No), the control unit 41 determines whether the concentration value is below the lower limit of the allowable range (step S304). For example, when the lower limit of the allowable range is 0.9 wt% (see FIG. 4), the control unit 41 determines whether the concentration value is below 0.9 wt%.

[0082] In step S304, when it is determined that the concentration value is below the lower limit of the allowable range (step S304, Yes), the control unit 41 sets the current replenishment mode to the second replenishment mode (step S305).

[0083] On the other hand, in step S304, when the concentration value is not below the lower limit of the allowable range (step S304, No), that is, when the concentration value exceeds the upper limit of the allowable range, the control unit 41 sets the current replenishment mode to the third replenishment mode (step S306).

[0084] After finishing the processes of steps S303, S305, and S306, the control unit 41 returns the process to step S301 and repeats the processes after step S301.

[0085] In this way, when the ammonia concentration deviates from the allowable range to the low-concentration side, the control unit 41 changes the replenishment mode from the first replenishment mode to the third replenishment mode. As a result, the replenishment amount of ammonia water in the regular replenishment process is changed from the first replenishment amount (for example, 50 ml) to the third replenishment amount (for example, 100 ml) that is more than the first replenishment amount. Also, the replenishment interval of ammonia water in the regular replenishment process is changed from the first time interval (for example, 100 sec) to the third time interval (for example, 50 sec) that is shorter than the first time interval.

[0086] Further, when the ammonia concentration deviates from the allowable range to the low concentration side, the determination interval in the feedback process is changed from the second time interval (for example, 30 sec) to a fourth time interval shorter than the second time interval (for example, 15 sec). Also, the replenishment amount of ammonia water in the feedback process is changed from the second replenishment amount (for example, 30 ml) to a fourth replenishment amount larger than the second replenishment amount (for example, 60 ml).

[0087] Therefore, according to the substrate processing apparatus 1 according to the embodiment, when the concentration of the evaporation component deviates from the allowable range to the low concentration side, the concentration of the evaporation component can be quickly returned to the allowable range.

[0088] Further, when the ammonia concentration deviates from the allowable range to the high concentration side, the control unit 41 changes the replenishment mode from the first replenishment mode to the third replenishment mode. As a result, the replenishment amount of ammonia water in the regular replenishment process is changed from the first replenishment amount to a fifth replenishment amount (for example, 20 ml) smaller than the first replenishment amount. Also, the replenishment interval of ammonia water in the regular replenishment process is changed from the first time interval to a fifth time interval (for example, 150 sec) longer than the first time interval.

[0089] Also, when the ammonia concentration deviates from the allowable range to the high concentration side, the determination interval in the feedback process is changed from the second time interval to a sixth time interval (for example, 120 sec) longer than the second time interval. Also, the replenishment amount of ammonia water in the feedback process is changed from the second replenishment amount to a sixth replenishment amount (for example, 5 ml) smaller than the second replenishment amount.

[0090] Therefore, according to the substrate processing apparatus 1 according to the embodiment, when the concentration of the evaporation component deviates from the allowable range to the high concentration side, the concentration of the evaporation component can be quickly returned to the allowable range.

[0091] Here, an example in which both the replenishment amount and the time interval are changed when the replenishment mode is changed has been described. However, the control unit 41 may change at least one of the replenishment amount and the time interval.

[0092] Also, in the regular replenishment process and the feedback replenishment process, when the ammonia concentration deviates from the allowable range to the high-concentration side, the control unit 41 may stop replenishing the aqueous ammonia. Thereby, the concentration of the evaporation component can be returned to the allowable range even faster.

[0093] <Regarding the position of the concentration meter in the circulation line> Incidentally, the filter 304 (see FIG. 3) corresponds to one of the pressure loss parts in the circulation line 301. That is, when the processing liquid passes through the filter 304, it undergoes a pressure loss due to friction with the filtration membrane. As a result, the pressure on the secondary side of the filter 304 becomes lower than the pressure on the primary side of the filter 304. The evaporation component in the processing liquid becomes more volatile as the pressure decreases. Therefore, when the processing liquid passes through the filter 304, the concentration of the evaporation component in the processing liquid may decrease.

[0094] This point will be described in comparison with the conventional processing liquid supply system. For example, in the conventional processing liquid supply system, a pump, a heater, a concentration meter, and a filter were provided in this order in the circulation line from the upstream side. That is, in the conventional processing liquid supply system, the concentration meter was provided upstream of the filter. In this case, the processing liquid passes through the filter after passing through the concentration meter.

[0095] As described above, the concentration of the evaporation component in the processing liquid may decrease on the secondary side of the filter. For example, assume that the concentration of the evaporation component in the processing liquid is maintained at a specified value until a plurality of wafers are immersed in the inner tank and the processing liquid in the inner tank passes through the pump, heater, and concentration meter. In this assumption, when the processing liquid passes through the filter, the evaporation component in the processing liquid evaporates, so that the concentration of the evaporation component in the processing liquid becomes lower than the specified value, and then the processing liquid with the lower concentration of the evaporation component is supplied to the inner tank.

[0096] Thus, in the conventional processing liquid supply system, there is a possibility that a deviation may occur between the evaporation component concentration (prescribed value) measured by the concentration meter and the evaporation component concentration (low) of the processing liquid supplied to the inner tank.

[0097] On the other hand, in the substrate processing apparatus 1 according to the embodiment, the ammonia concentration meter 306 is provided downstream of the filter 304. In this case, even if the evaporation component concentration of the processing liquid decreases on the secondary side of the filter 304, the evaporation component concentration of the processing liquid after the evaporation component concentration has decreased is measured by the ammonia concentration meter 306. For this reason, a deviation is less likely to occur between the evaporation component concentration measured by the ammonia concentration meter 306 and the evaporation component concentration of the processing liquid supplied to the inner tank 211. Therefore, according to the substrate processing apparatus 1 according to the embodiment, it is possible to more easily maintain the concentration of the evaporation component in the processing liquid.

[0098] <Modification example> FIG. 10 is a diagram showing the configuration of a processing liquid supply system 3 according to a modification example. As shown in FIG. 10, the processing liquid supply system 3 may include a dilution unit 33.

[0099] The dilution unit 33 includes a diluent supply source 331, a dilution line 332, and a flow rate adjuster 333. The diluent supply source 331 supplies a diluent. As the diluent, for example, DIW (deionized water) is used. The dilution line 332 connects the diluent supply source 331 and the outer tank 212, and supplies the diluent from the diluent supply source 331 to the outer tank 212. The flow rate adjuster 333 is provided in the dilution line 332 and adjusts the supply amount of the diluent supplied to the outer tank 212. The flow rate adjuster 333 is composed of, for example, an on-off valve, a flow control valve, a flow meter, or the like.

[0100] In the substrate processing apparatus 1 according to the modified example, when the ammonia concentration value exceeds the upper limit of the allowable range, the control unit 41 may perform a dilution process instead of, or together with, the replenishment process (third replenishment mode). Specifically, the control unit 41 controls the dilution unit 33 to supply a dilution liquid (here, DIW) from the dilution liquid supply source 331 to the outer tank 212 of the liquid processing unit 2. Thereby, the ammonia concentration can be quickly returned to the allowable range.

[0101] As described above, the substrate processing apparatus (as an example, the substrate processing apparatus 1) according to the embodiment is a substrate processing apparatus that processes a substrate by immersing the substrate (as an example, the wafer W) in a processing liquid (as an example, SC1) containing an evaporation component (as an example, ammonia). The substrate processing apparatus includes a processing tank (as an example, the processing tank 21), a regular replenishment unit (as an example, the regular replenishment unit 31) and a feedback replenishment unit (as an example, the feedback replenishment unit 32), a measurement unit (as an example, the ammonia concentration meter 306), and a control unit (as an example, the control unit 41). The processing tank stores the processing liquid. The regular replenishment unit and the feedback replenishment unit replenish the evaporation component. The measurement unit measures the concentration. The control unit controls the regular replenishment unit and the feedback replenishment unit. Further, the control unit performs a regular replenishment process and a feedback replenishment process. The regular replenishment process is a process of controlling the regular replenishment unit to replenish the evaporation component at a first replenishment amount and a first time interval so that the concentration of the evaporation component contained in the processing liquid falls within the allowable range. The feedback replenishment process is a process of controlling the feedback replenishment unit to execute a determination as to whether the concentration measured by the measurement unit is lower than a threshold value at a second time interval, and when it is determined that the concentration is lower than the threshold value, replenishing the evaporation component at a second replenishment amount. And the control unit performs the regular replenishment process and the feedback replenishment process in parallel.

[0102] By performing the regular replenishment process, the reduction rate of the evaporation component can be suppressed compared to the case where the regular replenishment process is not performed, so that the second replenishment amount in the feedback replenishment process can be reduced. Thereby, hunting of the concentration of the evaporation component can be suppressed, and thus it is possible to facilitate the maintenance of the concentration of the evaporation component contained in the processing liquid.

[0103] When the concentration measured by the measurement process is outside the allowable range on the low-concentration side, the periodic replenishment process changes the replenishment amount of the evaporation component to a third replenishment amount that is larger than the first replenishment amount, or changes the replenishment interval of the evaporation component to a third time interval that is shorter than the first time interval, and replenishes the evaporation component. Thereby, the concentration of the evaporation component can be quickly returned to the allowable range.

[0104] When the concentration measured by the measurement process is outside the allowable range on the low-concentration side, the feedback replenishment process changes the execution interval of the determination to a fourth time interval that is shorter than the second time interval, or changes the replenishment amount of the evaporation component to a fourth replenishment amount that is larger than the second replenishment amount, and replenishes the evaporation component. Thereby, the concentration of the evaporation component can be quickly returned to the allowable range.

[0105] When the concentration measured by the measurement process is outside the allowable range on the high-concentration side, the periodic replenishment process changes the replenishment amount of the evaporation component to a fifth replenishment amount that is less than the first replenishment amount, or changes the replenishment interval of the evaporation component to a fifth time interval that is longer than the first time interval to replenish the evaporation component, or stops the replenishment of the evaporation component. Thereby, the concentration of the evaporation component can be quickly returned to the allowable range.

[0106] When the concentration measured by the measurement process is outside the allowable range on the high-concentration side, the feedback replenishment process changes the execution interval of the determination to a sixth time interval that is longer than the second time interval, or changes the replenishment amount of the evaporation component to a sixth replenishment amount that is less than the second replenishment amount to replenish the evaporation component, or stops the replenishment of the evaporation component. Thereby, the concentration of the evaporation component can be quickly returned to the allowable range.

[0107] The substrate processing apparatus 1 according to the embodiment may include a dilution unit 33. In this case, the control unit 41 may perform a dilution process. The dilution process can quickly return the concentration of the evaporation component to the allowable range by replenishing a liquid that does not contain the evaporation component when the concentration measured by the measurement process is outside the allowable range on the high-concentration side.

[0108] For the dilution process, water may be replenished as a liquid that does not contain evaporation components. Thereby, the dilution process can be realized at a relatively low cost.

[0109] The processing tank may include an inner tank (for example, inner tank 211) that has an opening at the upper part and can accommodate a substrate, and an outer tank (for example, outer tank 212) that is disposed outside the inner tank and receives the processing liquid flowing out from the opening. In this case, the processing liquid stored in the outer tank may be returned to the inner tank by a circulation line (for example, circulation line 301) that connects the outer tank and the inner tank. Further, for the periodic replenishment process and the feedback replenishment process, evaporation components may be replenished to the outer tank or the circulation line.

[0110] By replenishing evaporation components to the outer tank or the circulation line, since the evaporation components can be efficiently mixed into the processing liquid by utilizing the flow of the processing liquid through the circulation line, the concentration of the evaporation components can be stabilized at an early stage.

[0111] The processing liquid may be any one of SC1 containing ammonia as an evaporation component, dilute ammonia water, and BHF, SC2 containing hydrogen peroxide as an evaporation component, SPM, fluonitric acid containing nitric acid as an evaporation component, PAN, and phosphoric acid aqueous solution. The substrate processing method according to the embodiment can facilitate the maintenance of the concentration of the evaporation components contained in these processing liquids.

[0112] It should be considered that all the embodiments disclosed this time are illustrative in all respects and not restrictive. Indeed, the above-described embodiments can be embodied in various forms. Also, the above embodiments may be omitted, substituted, or changed in various forms without departing from the scope and spirit of the appended claims.

Explanation of Reference Numerals

[0113] 1; Substrate processing apparatus 2; Liquid processing unit 3; Processing liquid supply system 4; Control device 21; Processing tank 22; Holding part 23; Discharging part 30; Circulation part 31; Periodic replenishment part 32; Feedback replenishment part 33; Dilution part 41; Control part 42; Memory part 211; Inner tank 212; Outer tank 301; Circulation line 302; Pump 303; Heater 304; Filter 306; Ammonia concentration meter 308; Hydrogen peroxide concentration meter

Claims

1. A substrate processing method for processing a substrate by immersing the substrate in a processing liquid containing an evaporation component, comprising: a regular replenishment step of controlling a regular replenishment unit that replenishes the evaporation component using a first replenishment line so that the concentration of the evaporation component in the processing liquid remains within an allowable range, and replenishing the evaporation component at a first replenishment amount and a first time interval; a measurement step of measuring the concentration; determining whether the concentration measured in the measurement step is below a threshold value at a second time interval, and when it is determined that the concentration is below the threshold value, controlling a feedback replenishment unit that replenishes the evaporation component using a second replenishment line, and replenishing the evaporation component at a second replenishment amount; and performing the regular replenishment step and the feedback replenishment step in parallel.

2. The regular replenishment step includes: when the concentration measured in the measurement step deviates from the allowable range to the low concentration side, changing the replenishment amount of the evaporation component to a third replenishment amount that is greater than the first replenishment amount, or changing the replenishment interval of the evaporation component to a third time interval that is shorter than the first time interval, and replenishing the evaporation component. The substrate processing method according to claim 1.

3. The feedback replenishment step includes: when the concentration measured in the measurement step deviates from the allowable range to the low concentration side, changing the execution interval of the determination to a fourth time interval that is shorter than the second time interval, or changing the replenishment amount of the evaporation component to a fourth replenishment amount that is greater than the second replenishment amount, and replenishing the evaporation component. The substrate processing method according to claim 1 or 2.

4. The regular replenishment step includes: when the concentration measured in the measurement step deviates from the allowable range to the high concentration side, changing the replenishment amount of the evaporation component to a fifth replenishment amount that is less than the first replenishment amount, or changing the replenishment interval of the evaporation component to a fifth time interval that is longer than the first time interval and replenishing the evaporation component, or stopping the replenishment of the evaporation component. The substrate processing method according to any one of claims 1 to 3.

5. The feedback replenishment step includes: When the concentration measured in the measurement step deviates from the allowable range to the high-concentration side, change the execution interval of the determination to a sixth time interval longer than the second time interval, or change the replenishment amount of the evaporation component to a sixth replenishment amount less than the second replenishment amount to replenish the evaporation component, or stop the replenishment of the evaporation component. The substrate processing method according to any one of claims 1 to 4.

6. A dilution step of replenishing a liquid not containing the evaporation component when the concentration measured in the measurement step deviates from the allowable range to the high-concentration side The substrate processing method according to any one of claims 1 to 5, including

7. The dilution step is The substrate processing method according to claim 6, wherein water is replenished as the liquid not containing the evaporation component.

8. The regular replenishment step is When the concentration measured in the measurement step is within the allowable range, replenish the evaporation component at the first replenishment amount and the first time interval. The feedback replenishment step is When the concentration measured in the measurement step is within the allowable range, execute the determination at the second time interval and replenish the evaporation component at the second replenishment amount. The substrate processing method according to any one of claims 1 to 7.

9. The substrate is immersed in the processing liquid stored in the processing tank. The processing tank is An inner tank having an opening at the upper part and capable of accommodating the substrate, and An outer tank disposed outside the inner tank and receiving the processing liquid flowing out from the opening Comprising The processing liquid stored in the outer tank is returned to the inner tank through a circulation line connecting the outer tank and the inner tank. The regular replenishment step and the feedback replenishment step are Replenish the evaporation component to the outer tank or the circulation line. The substrate processing method according to any one of claims 1 to 8.

10. The processing liquid is any one of SC1 containing ammonia as the evaporation component, dilute aqueous ammonia, and BHF, SC2 containing hydrogen peroxide as the evaporation component, and SPM, fluonitric acid containing nitric acid as the evaporation component, and PAN and phosphoric acid aqueous solution. The substrate processing method according to any one of claims 1 to 9.

11. A substrate processing apparatus for processing a substrate by immersing the substrate in a processing liquid containing an evaporation component, A processing tank for storing the processing liquid, A regular replenishment unit for replenishing the evaporation component using a first replenishment line, A feedback replenishment unit that replenishes the evaporation component using the second replenishment line; A measurement unit that measures the concentration of the evaporation component; A control unit that controls the periodic replenishment unit and the feedback replenishment unit; and; The control unit: Controls the periodic replenishment unit to perform a periodic replenishment process of replenishing the evaporation component at a first replenishment amount and a first time interval so that the concentration of the evaporation component contained in the processing liquid falls within an allowable range; Controls the feedback replenishment unit to execute, at a second time interval, a determination as to whether or not the concentration measured by the measurement unit is lower than a threshold value, and when it is determined that the concentration is lower than the threshold value, performs a feedback replenishment process of replenishing the evaporation component at a second replenishment amount; A substrate processing apparatus that performs these processes in parallel.

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