Substrate processing apparatus and substrate processing method

Abstract

Described is a substrate processing apparatus and a substrate processing method, by which work efficiency can be improved while suppressing variations in the etching amount of substrates.　This substrate processing apparatus includes: a processing tank configured to perform etching processing of a substrate with a processing liquid; a measurement unit configured to measure a silicon concentration of the processing liquid; and a control unit. The control unit is configured to execute: processing for estimating a post-processing concentration, which is a silicon concentration of the processing liquid in the processing tank after the etching processing of the substrate, on the basis of a value related to an amount of polysilicon included in the substrate, and a pre-processing concentration, which is measured by the measurement unit and is a silicon concentration of the processing liquid in the processing tank before the etching processing of the substrate; and processing for determining a processing time of the substrate in the processing tank on the basis of correlation data and the estimated post-processing concentration.

Description

Substrate processing apparatus and substrate processing method

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

[0002] Patent Document 1 discloses a substrate processing apparatus for processing substrates placed in a processing tank by controlling a pure water supply means for supplying pure water to the processing tank and a substrate processing liquid supply means for supplying a substrate processing liquid to the processing tank. The substrate processing apparatus supplies the substrate processing liquid to the processing tank filled with pure water to replace the pure water with the substrate processing liquid, thereby diluting and preparing the substrate processing liquid, and determines the immersion time of the substrate in the substrate processing liquid based on the concentration of the diluted substrate processing liquid.

[0003] Japanese Patent Application Publication No. 8-010673

[0004] The present disclosure describes a substrate processing apparatus and a substrate processing method that can improve work efficiency while suppressing variations in the amount of etching of a substrate.

[0005] An example of a substrate processing apparatus is a substrate processing apparatus configured to etch a substrate containing polysilicon using an alkaline processing liquid, and includes a processing tank configured to etch the substrate using the processing liquid, a measurement unit configured to measure the silicon concentration of the processing liquid, and a control unit.The control unit is configured to perform the following processes: a process of estimating a post-processing concentration, which is the silicon concentration of the processing liquid in the processing tank after the etching processing of the substrate, based on a value related to the amount of polysilicon contained in the substrate and a pre-processing concentration, which is the silicon concentration of the processing liquid in the processing tank before the etching processing of the substrate; and a process of determining the processing time of the substrate in the processing tank based on correlation data showing the correlation between the silicon concentration of the processing liquid in the processing tank after the sample substrate has been etched in the processing tank with the processing liquid and the etching rate of the sample substrate due to the etching processing, and the estimated post-processing concentration.

[0006] According to the substrate processing apparatus and substrate processing method of the present disclosure, it is possible to improve work efficiency while suppressing variations in the amount of etching of substrates.

[0007] FIG. 1 is a top view showing an example of a substrate processing system. FIG. 2( a) is a schematic cross-sectional view showing a substrate in one step of an etching process. FIG. 2( b) is a schematic cross-sectional view showing a substrate in a step subsequent to the step shown in FIG. 2( a). FIG. 3 is a schematic view showing an example of a substrate cleaning apparatus. FIG. 4 is a block diagram showing an example of a main part of a substrate processing system. FIG. 5 is a graph showing an example of first correlation data. FIG. 6 is a graph showing an example of second correlation data. FIG. 7 is a graph showing an example of third correlation data. FIG. 8 is a schematic diagram showing an example of a hardware configuration of a controller. FIG. 9 is a flowchart showing an example of a process for generating first correlation data. FIG. 10 is a flowchart showing an example of a process for generating second correlation data. FIG. 11 is a flowchart showing an example of a process for generating third correlation data. FIG. 12 is a flowchart showing an example of an etching process. FIG. 13 is a flowchart showing an example of a process liquid replacement process shown in FIG. 12. FIG. 14 is a flowchart showing an example of a process time determination process shown in FIG. 12. FIG. 15 is a flowchart showing an example of a process time correction process shown in FIG. 12. FIG. 16 is a flowchart showing an example of the mixed liquid concentration adjustment process.

[0008] In the following description, the same elements or elements having the same functions will be designated by the same reference numerals, and redundant explanations will be omitted. Note that in this specification, when referring to the top, bottom, right, and left of a figure, the directions of the reference numerals in the figure will be used as the reference.

[0009] First, the configuration of a substrate processing system 1 (substrate processing apparatus) will be described with reference to Fig. 1. The substrate processing system 1 includes a carrier loading / unloading unit 2, a lot formation unit 3, a lot placement unit 4, a lot processing unit 5, and a controller Ctr (control unit).

[0010] The carrier loading / unloading section 2 includes a stage 2a, a mounting table 2b, a transport mechanism 2c, and a stock 2d. The stage 2a is configured to be able to mount a plurality of carriers 6. The mounting table 2b is configured to be able to mount a single carrier 6. The transport mechanism 2c is located between the stage 2a and the mounting table 2b. The transport mechanism 2c operates based on an operation signal from the controller Ctr, and is configured to transport the carriers 6 between the stage 2a, the mounting table 2b, and the stock 2d. The stock 2d is configured to temporarily store the carriers 6.

[0011] The carrier 6 is configured to accommodate a plurality of substrates W (e.g., 25 substrates W) arranged one above the other in a horizontal orientation. In this specification, a horizontal orientation refers to an orientation in which the main surface of the substrate W is aligned horizontally. The substrate W may be disk-shaped or may have a non-circular plate shape, such as a polygonal shape. The substrate W may have a cutout portion cut out from a portion of the substrate. The cutout portion may be, for example, a notch (a U-shaped, V-shaped, or other groove) or a linear portion extending linearly (a so-called orientation flat). The substrate W may be, for example, a semiconductor substrate (silicon wafer), a glass substrate, a mask substrate, a FPD (Flat Panel Display) substrate, or any other type of substrate. The diameter of the substrate W may be, for example, approximately 200 mm to 450 mm.

[0012] Each carrier 6 includes a sensor (not shown) configured to acquire the number of substrates W accommodated in the carrier 6. The sensor may be configured, for example, to detect the presence or absence of substrates W supported by support slots provided in the carrier 6, and count the number of substrates W in the carrier 6. The sensor is configured to transmit the acquired data on the number of substrates W to the controller Ctr.

[0013] The lot forming unit 3 includes a transport mechanism 3a configured to form one lot by taking out one or more substrates W from one or more carriers 6. The plurality of substrates W (e.g., 50 substrates) constituting one lot are simultaneously processed in the lot processing unit 5.

[0014] When the lot forming unit 3 takes out one or more substrates W from each of the plurality of carriers 6, each sensor acquires the number of substrates W taken out from the corresponding carrier 6 and transmits the data of the number to the controller Ctr. Based on the received data, the controller Ctr calculates the number of substrates W that constitute one lot in the lot forming unit 3.

[0015] The transport mechanism 3a is configured to operate based on an operation signal from the controller Ctr and to change the attitude of the substrate W between a horizontal attitude and a vertical attitude during transport of the substrate W. In this specification, the vertical attitude refers to an attitude in which the main surface of the substrate W is aligned along the vertical direction.

[0016] The transport mechanism 3a, for example, takes out one substrate W from the carrier 6 placed on the mounting table 2b, changes its orientation to a vertical orientation, and transports the vertically oriented substrate W to the lot mounting part 4. The transport mechanism 3a repeats this process to form one lot (plurality of substrates W arranged one behind the other in a vertical orientation) on the lot mounting part 4. On the other hand, the transport mechanism 3a takes out one substrate W from the lot placed on the lot mounting part 4, changes its orientation to a horizontal orientation, and transports the horizontally oriented substrate W to the carrier 6 on the mounting table 2b. The transport mechanism 3a repeats this process to store all of the substrates W that make up the lot into one or more carriers 6.

[0017] The lot placement unit 4 includes a placement stage 4a on which lots transported between the lot formation unit 3 and the lot processing unit 5 are temporarily placed. The placement stage 4a may include a pre-processing lot placement stage 4b ​​configured to place lots before they are processed in the lot processing unit 5, and a post-processing lot placement stage 4c configured to place lots after they have been processed in the lot processing unit 5.

[0018] The lot processing section 5 is configured to perform processes such as etching, cleaning, drying, etc. on a single lot, which consists of a plurality of substrates W arranged vertically one behind the other. The lot processing section 5 includes a transport mechanism 7, a drying processing device 8, a cleaning processing device 9, and a plurality of liquid processing devices 10.

[0019] 1 , the transport mechanism 7 is configured to operate based on an operation signal from the controller Ctr and transport lots between the lot mounting unit 4, the drying treatment device 8, the cleaning treatment device 9, and multiple liquid treatment devices 10. The transport mechanism 7 includes a rail 7a, a movable body 7b, and a holder 7c. The rail 7a is disposed to extend between the lot mounting unit 4 and the lot treatment device 5. The movable body 7b is configured to be movable along the rail 7a. The holder 7c is provided on the movable body 7b and configured to hold lots (multiple substrates W arranged in a vertical position one behind the other).

[0020] The drying treatment device 8 is configured to operate based on an operation signal from the controller Ctr and to perform drying treatment on the substrate W using a drying treatment gas (e.g., isopropyl alcohol, etc.). The cleaning treatment device 9 is configured to operate based on an operation signal from the controller Ctr and to perform cleaning treatment on the holder 7 c using a cleaning treatment liquid and a drying gas.

[0021] The liquid processing apparatus 10 is configured to process a substrate W (for example, to remove dirt or foreign matter, or to perform etching, etc.) with a processing liquid L (see FIG. 3). The processing liquid L is an alkaline liquid. The processing liquid L is a mixture of a chemical liquid L1 (see FIG. 3) and ultrapure water (DIW: deionized water) L2 (see FIG. 3). The processing liquid L may also be a mixture of the ultrapure water L2 and a plurality of types of chemical liquid L1.

[0022] The treatment liquid L may be, for example, an SC-1 liquid, an NC-2 liquid, or TMAH. The SC-1 liquid is a mixture containing ammonium hydroxide, hydrogen peroxide, and ultrapure water L2. That is, in the SC-1 liquid, the ammonium hydroxide and hydrogen peroxide correspond to the chemical liquid L1. The NC-2 liquid is a mixture containing choline (aqueous trimethyl-2-hydroxyethylammonium hydroxide solution), hydrogen peroxide, and ultrapure water L2. That is, in the NC-2 liquid, the choline and hydrogen peroxide correspond to the chemical liquid L1. TMAH is a mixture containing tetramethylammonium hydroxide and ultrapure water L2. That is, in the TMAH liquid, the tetramethylammonium hydroxide corresponds to the chemical liquid L1. When the SC-1 liquid is used as the treatment liquid L, the concentration of the ammonium hydroxide may be approximately 28% to 30% by weight, and the concentration of the hydrogen peroxide may be approximately 30% to 32% by weight.

[0023] [Details of the Substrate] Next, an example of one step of an etching process performed by the liquid processing apparatus 10 will be described with reference to Fig. 2. Fig. 2(a) is a schematic cross-sectional view showing a substrate W in one step of the etching process. The substrate W is, for example, an intermediate product in the manufacturing process of a semiconductor device (e.g., a 3D NAND memory, etc.). The substrate W includes a plurality of layers W1 and a semiconductor substrate W2.

[0024] The layers W1 are made up of a plurality of silicon nitride (SiN) films W3 and a plurality of silicon oxide (SiO ２ ) W4. A plurality of silicon nitride films W3 and a plurality of silicon oxide films W4 are alternately stacked on the semiconductor substrate W2 to form a stacked body. The stacked body includes a channel hole H extending in the stacking direction of the stacked body. The stacked body includes a polysilicon (Poly-Si) film W5 formed in the channel hole H. The polysilicon film W5 is formed at a position corresponding to each of the plurality of layers W1 in the stacking direction of the stacked body. In other words, each of the plurality of layers W1 includes polysilicon at a position corresponding to the channel hole H.

[0025] Fig. 2(b) is a schematic cross-sectional view showing the substrate W in a step subsequent to the step shown in Fig. 2(a). The liquid treatment apparatus 10 etches the polysilicon film W5 of the substrate W immersed in the treatment liquid L. In the etching process, the substrate W is immersed in the treatment liquid L, and thereby a portion of the polysilicon film W5 is dissolved in the treatment liquid L. The liquid treatment apparatus 10 etches the polysilicon film W5 of the substrate W, thereby reducing the thickness of the polysilicon film W5.

[0026] The liquid processing apparatus 10 performs an etching process on the substrate W by immersing the substrate W in the processing liquid L for a processing time determined before the etching process. Here, in order to etch the substrate W by a desired amount, it is necessary to appropriately determine the processing time for the substrate W. For example, the processing time for the substrate W can be determined depending on the silicon concentration of the processing liquid L. When the silicon concentration of the processing liquid L increases, the reactions shown in the following chemical reaction formulas (1) and (2) proceed, thereby decreasing the etching rate of the processing liquid L. Therefore, the processing time for the substrate W can be set to increase as the silicon concentration of the processing liquid L increases. Si + 2HO ２ － → SiO ２ +2OH － ... (1) SiO ２ +2OH － → H ２ SiO ４ ２－ ... (2)

[0027] [Details of Liquid Treatment Apparatus] Next, liquid treatment apparatus 10 will be described in detail with reference to Fig. 3. Liquid treatment apparatus 10 includes a treatment tank 20, a holding unit 30, a circulation unit 40, a supply unit 50, and a discharge unit 60.

[0028] The processing tank 20 is configured to perform an etching process on the substrates W using the processing liquid L. The processing tank 20 includes an inner tank 21 and an outer tank 22. The inner tank 21 is configured to store the processing liquid L. The top of the inner tank 21 is open upward. This allows the substrates W to be immersed in the processing liquid L in the inner tank 21 from above. The outer tank 22 is provided to surround the inner tank 21. The outer tank 22 is configured to temporarily store the processing liquid L that overflows from the inner tank 21 and flows into it. The upper end of the outer tank 22 may be located higher than the upper end of the inner tank 21.

[0029] The holder 30 includes a holding member 31. The holding member 31 is configured to receive one lot from the transport mechanism 7 and hold the multiple substrates W constituting the lot in a vertical position. The holding member 31 is connected to a drive mechanism (not shown). The drive mechanism is configured to operate based on an operation signal from the controller Ctr to move the holding member 31 up and down. The holding member 31 is movable, for example, between a lowered position (see FIG. 3 ) in which the multiple substrates W it holds are immersed in the processing liquid L in the inner bath 21 and an elevated position in which the multiple substrates W it holds are positioned above the inner bath 21. At the lowered position, the multiple substrates W held by the holding member 31 are etched with the processing liquid L in the inner bath 21. At the elevated position, the multiple substrates W held by the holding member 31 are transferred by the transport mechanism 7.

[0030] The holding member 31 includes a back plate portion 32 and a plurality of arm portions 33. The back plate portion 32 has a flat plate shape extending in the vertical direction. Each of the plurality of arm portions 33 is connected to a lower end of the back plate portion 32. Each of the plurality of arm portions 33 extends in the horizontal direction. The plurality of arm portions 33 are arranged at predetermined intervals in the width direction of the back plate portion 32. By placing the peripheral portion of a vertically oriented substrate W on the arm portions 33, the substrate W is held by the arm portions 33 while maintaining the vertical orientation. In other words, the arm portions 33 can support a plurality of vertically oriented substrates W aligned in the extension direction of the arm portions 33.

[0031] The circulation unit 40 is configured to supply the processing liquid L in the outer bath 22 to the inner bath 21. The circulation unit 40 includes a circulation path 41, a pump 42, a heater 43, and a filter 44.

[0032] The circulation path 41 is a pipe extending from the outer bath 22 toward the inner bath 21. The circulation path 41 is provided with a pump 42, a heater 43, and a filter 44 in this order from the upstream side (the outer bath 22 side).

[0033] The pump 42 operates based on an operation signal from the controller Ctr and is configured to send the processing liquid L from the outer bath 22 to the inner bath 21 through the circulation path 41. The pump 42 is, for example, a pressure pump. The heater 43 operates based on an operation signal from the controller Ctr and is configured to heat the processing liquid L to a predetermined set temperature (for example, approximately 40°C to 80°C). The filter 44 is configured to collect foreign matter (for example, particles, etc.) contained in the processing liquid L.

[0034] The circulation unit 40 further includes a branch path 45, a first measurement unit 46 (measurement unit), a branch path 47, a valve 47a, and a second measurement unit 48 (another measurement unit). The branch path 45 is a pipe branching off from the circulation path 41. The branch path 45 branches off from the circulation path 41 between the heater 43 and the filter 44. The branch path 45 is configured to guide the processing liquid L flowing through the circulation path 41 to the outside of the substrate processing system 1.

[0035] The first measuring unit 46 is configured to measure the silicon concentration of the processing liquid L. The first measuring unit 46 is provided in the branch path 45. The first measuring unit 46 is configured to continuously measure the silicon concentration of the processing liquid L over time. The first measuring unit 46 may be, for example, an optical emission spectrometer using plasma. The optical emission spectrometer may be, for example, an optical emission spectrometer using nitrogen plasma (one example is the "MP-AES" manufactured by Agilent Technologies). The first measuring unit 46 is configured to transmit the measured silicon concentration value to the controller Ctr.

[0036] The branch path 47 is a pipe branching off from the branch path 45. The branch path 47 branches off from the branch path 45 on the upstream side (the circulation path 41 side) of the first measuring unit 46. The branch path 47 is configured to guide the processing liquid L flowing through the circulation path 41 and the branch path 45 to the outside of the substrate processing system 1.

[0037] The valve 47a is provided in the branch path 47. The valve 47a is configured such that the opening degree thereof is controlled based on an operation signal from the controller Ctr, and the branch path 47 is fluidly opened or closed.

[0038] The second measuring unit 48 is configured to measure the concentration of the mixed liquid. The second measuring unit 48 is provided in the circulation path 41. The second measuring unit 48 may be configured to measure the concentration of the liquid using, for example, absorption spectroscopy. For example, the second measuring unit 48 may be configured to measure the concentration of the liquid using infrared spectroscopy (IR). The second measuring unit 48 may be configured to measure the concentration of the liquid using near-infrared spectroscopy (NIR). The second measuring unit 48 is configured to transmit the measured value of the concentration of the mixed liquid to the controller Ctr.

[0039] The supply unit 50 is configured to supply the processing liquid L to the processing bath 20. The supply unit 50 is configured to supply at least one of ultrapure water L2 and chemical liquid L1 to the processing bath 20.

[0040] The supply unit 50 includes an ammonium hydroxide supply source 51, a supply path 51a, and a valve 51b. The ammonium hydroxide supply source 51 supplies ammonium hydroxide (NH ４The supply path 51a is configured to store an aqueous solution of ammonium hydroxide (OH). The supply path 51a is a pipe extending from the ammonium hydroxide supply source 51 to the inner tank 21. A valve 51b is provided in the supply path 51a. The opening of the valve 51b is controlled based on an operation signal from the controller Ctr, and the valve 51b is configured to fluidly open or close the supply path 51a. The controller Ctr adjusts the opening of the valve 51b, thereby adjusting the flow rate of the aqueous ammonium hydroxide solution flowing through the supply path 51a. When the valve 51b is open, the aqueous ammonium hydroxide solution is supplied from the ammonium hydroxide supply source 51 to the inner tank 21 through the supply path 51a.

[0041] The supply unit 50 further includes an ammonium hydroxide supply source 52, a supply path 52a, and a valve 52b. The configuration of the ammonium hydroxide supply source 52 is similar to that of the ammonium hydroxide supply source 51. The supply path 52a is a pipe extending from the ammonium hydroxide supply source 52 to the outer tank 22. A valve 52b is provided in the supply path 52a. The opening of the valve 52b is controlled based on an operation signal from the controller Ctr, and the valve 52b is configured to fluidly open or close the supply path 52a. The configuration of the valve 52b is similar to that of the valve 51b.

[0042] The supply unit 50 further includes a hydrogen peroxide solution supply source 53, a supply path 53a, and a valve 53b. The hydrogen peroxide solution supply source 53 supplies hydrogen peroxide solution (H ２ O ２ ) is stored in the inner tank 21. The supply path 53a is a pipe extending from the hydrogen peroxide solution supply source 53 to the inner tank 21. A valve 53b is provided in the supply path 53a. The opening of the valve 53b is controlled based on an operation signal from the controller Ctr, and the valve 53b is configured to fluidly open or close the supply path 53a. The configuration of the valve 53b is similar to the configuration of the valve 51b.

[0043] The supply unit 50 further includes a hydrogen peroxide solution supply source 54, a supply path 54a, and a valve 54b. The configuration of the hydrogen peroxide solution supply source 54 is similar to that of the hydrogen peroxide solution supply source 53. The supply path 54a is a pipe extending from the hydrogen peroxide solution supply source 54 to the outer bath 22. A valve 54b is provided in the supply path 54a. The opening of the valve 54b is controlled based on an operation signal from the controller Ctr, and the valve 54b is configured to fluidly open or close the supply path 54a. The configuration of the valve 54b is similar to that of the valve 51b.

[0044] The supply unit 50 further includes an ultrapure water supply source 55, a supply path 55a, and a valve 55b. The ultrapure water supply source 55 is configured to store ultrapure water L2. The supply path 55a is a pipe extending from the ultrapure water supply source 55 to the inner bath 21. A valve 55b is provided in the supply path 55a. The opening of the valve 55b is controlled based on an operation signal from the controller Ctr, and the valve 55b is configured to fluidly open or close the supply path 55a. The configuration of the valve 55b is similar to the configuration of the valve 51b.

[0045] The supply unit 50 further includes an ultrapure water supply source 56, a supply path 56a, and a valve 56b. The configuration of the ultrapure water supply source 56 is similar to that of the ultrapure water supply source 55. The supply path 56a is a pipe extending from the ultrapure water supply source 56 to the outer bath 22. A valve 56b is provided in the supply path 56a. The opening of the valve 56b is controlled based on an operation signal from the controller Ctr, and the valve 56b is configured to fluidly open or close the supply path 56a. The configuration of the valve 56b is similar to that of the valve 51b.

[0046] The discharge unit 60 is configured to discharge the processing liquid L in the processing tank 20 to the outside of the processing tank 20. The discharge unit 60 may be configured to discharge, for example, the processing liquid L in the inner tank 21 to the outside of the processing tank 20. The discharge unit 60 includes a discharge path 61 and a valve 62.

[0047] The discharge path 61 is a pipe extending from the inner tank 21 to the outside of the treatment tank 20. A valve 62 is provided in the discharge path 61. The opening degree of the valve 62 is controlled based on an operation signal from the controller Ctr, and the valve 62 is configured to fluidly open or close the discharge path 61. The controller Ctr adjusts the opening degree of the valve 62, thereby adjusting the flow rate of the treatment liquid L flowing through the discharge path 61. When the valve 62 is open, the treatment liquid L is discharged from the inner tank 21 through the discharge path 61 to the outside of the treatment tank 20.

[0048] [Details of the Controller] Next, the controller Ctr will be described in detail with reference to FIG. 4. The controller Ctr has a reading unit M1, a memory unit M2, a processing unit M3, and an instruction unit M4 as functional modules. These functional modules merely divide the functions of the controller Ctr into multiple modules for convenience, and do not necessarily mean that the hardware constituting the controller Ctr is divided into such modules. Each functional module is not limited to being realized by executing a program. Each functional module may be realized, for example, by a dedicated electrical circuit (e.g., a logic circuit), an integrated circuit (ASIC: Application Specific Integrated Circuit) that integrates such a circuit, or the like.

[0049] The reading unit M1 is configured to read a program from a computer-readable recording medium RM. The recording medium RM stores a program for operating each unit of the substrate processing system 1. The recording medium RM may be, for example, a semiconductor memory, an optical recording disk, a magnetic recording disk, or a magneto-optical recording disk. In this specification, each unit of the substrate processing system 1 may be, for example, the holding unit 30, the pump 42, the heater 43, the supply unit 50, the discharge unit 60, etc.

[0050] The memory unit M2 is configured to store various data. The memory unit M2 may store, for example, a program read from the recording medium RM by the reading unit M1, setting data input by an operator via an external input device (not shown), and the like. The memory unit M2 may store, for example, the silicon concentration value measured by the first measuring unit 46 and the concentration value of the mixed solution measured by the second measuring unit 48. The external input device is configured to receive data such as the number of stacked substrates W and the etching amount of the substrates W based on input operations by the operator, and transmit the data to the controller Ctr. The external input device may be, for example, a touch panel, a keyboard, a mouse, or the like.

[0051] The memory unit M2 pre-stores first correlation data (another correlation data), second correlation data (correlation data), and third correlation data (further correlation data). These correlation data may be generated in advance by, for example, conducting an experiment using an experimental substrate (hereinafter sometimes referred to as a "sample substrate Wa") different from the substrate W. The configuration of the sample substrate Wa is the same as the configuration of the substrate W. A method for generating these correlation data will be described later. In the description of the correlation data to be described later, the term "sample substrate Wa" will be used when the substrate W and the sample substrate Wa are to be distinguished from each other. When there is no need to distinguish between the substrate W and the sample substrate Wa, the term "substrate W" will be used.

[0052] The first correlation data is used to estimate the amount of change in the silicon concentration of the processing liquid L in the processing tank 20 after the etching processing of the substrates W. The amount of change is the amount of change in the silicon concentration of the processing liquid L caused by simultaneously etching the substrates W that constitute one lot in the processing tank 20.

[0053] As shown in Fig. 5, the first correlation data can be expressed as a two-axis graph. In the example of Fig. 5, the horizontal axis indicates the number of sample substrates Wa processed simultaneously in the processing tank 20, and the vertical axis indicates the amount of change in silicon concentration. The first correlation data indicates the correlation between a value related to the amount of polysilicon contained in the sample substrates Wa and the amount of change in silicon concentration in the processing liquid L after the etching processing of the sample substrates Wa. The value related to the amount of polysilicon is a value that correlates with the amount of polysilicon contained in the sample substrates Wa. The value related to the amount of polysilicon includes the number of sample substrates Wa processed simultaneously in the processing tank 20 and the number of layers W1 stacked on the sample substrates Wa.

[0054] The second correlation data is used to determine the processing time of the substrate W in the processing tank 20. The processing time is the time for which the substrate W is immersed in the processing liquid L in the processing tank 20. As shown in Fig. 6, the second correlation data can be expressed as a two-axis graph. In the example of Fig. 6, the horizontal axis represents the post-processing concentration of the processing liquid L (the silicon concentration of the processing liquid L in the processing tank 20 after the etching processing of the sample substrate Wa), and the vertical axis represents the etching rate of the sample substrate Wa. The second correlation data indicates the correlation between the post-processing concentration of the processing liquid L and the etching rate of the sample substrate Wa due to the etching processing.

[0055] The third correlation data is used to estimate the amount of change in silicon concentration in the processing liquid L when the substrate W is etched for a predetermined time. As shown in Fig. 7 , the third correlation data can be expressed as a two-axis graph. In the example of Fig. 7 , the horizontal axis represents the processing time of the sample substrate Wa, and the vertical axis represents the amount of change in silicon concentration. The third correlation data shows the correlation between the processing time of the sample substrate Wa and the amount of change in silicon concentration in the processing liquid L after the etching processing of the sample substrate Wa.

[0056] The processing unit M3 is configured to process various types of data. For example, the processing unit M3 may be configured to generate operation signals for operating each unit of the substrate processing system 1 based on the various types of data stored in the storage unit M2. The instruction unit M4 is configured to transmit the operation signals generated in the processing unit M3 to each unit of the substrate processing system 1.

[0057] The hardware of the controller Ctr may be configured, for example, by one or more control computers. The controller Ctr may include, for example, a circuit C1 shown in FIG. 8 as a hardware configuration. The circuit C1 may be configured by electrical circuit elements. The circuit C1 may include, for example, a processor C2, a memory C3, a storage C4, a driver C5, and an input / output port C6. The processor C2 executes programs in cooperation with at least one of the memory C3 and the storage C4 and inputs and outputs signals via the input / output port C6, thereby configuring the above-mentioned functional modules. The memory C3 and the storage C4 function as a memory unit M2. The driver C5 is a circuit that drives each component of the substrate processing system 1. The input / output port C6 inputs and outputs signals between the driver C5 and each component of the substrate processing system 1.

[0058] The substrate processing system 1 may include one controller Ctr, or may include a controller group (controller) composed of multiple controllers Ctr. In the latter case, each of the above-mentioned functional modules may be realized by one controller Ctr or by a combination of two or more controllers Ctr. When the controller Ctr is composed of multiple computers (circuits C1), each of the above-mentioned functional modules may be realized by one or multiple computers (circuits C1). The controller Ctr may include multiple processors C2. In this case, each of the above-mentioned functional modules may be realized by one processor C2 or by a combination of two or more processors C2.

[0059] 9 to 11, a process for generating the first correlation data, the second correlation data, and the third correlation data will be described. The process for generating the correlation data is performed in advance before the etching process of the substrate W is performed by the substrate processing system 1.

[0060] [Process for Generating First Correlation Data] First, the process for generating first correlation data will be described. As shown in FIG. 9 , preparations for generating first correlation data are first made (step S1). In step S1, the operator first prepares a plurality of sample substrates Wa. The plurality of sample substrates Wa are identical in size and shape. For example, the operator prepares a sample substrate Wm having a plurality of layers W1 stacked in M ​​layers and a sample substrate Wn having a plurality of layers W1 stacked in N layers (M and N are any natural numbers different from each other). In step S1, for example, the operator may prepare a plurality of sample substrates Wm and a plurality of sample substrates Wn.

[0061] In step S1, the controller Ctr supplies the processing liquid L to the processing tank 20. The controller Ctr controls the valves 51b, 53b, and 55b to open the valves, thereby supplying the chemical liquid L1 (ammonium hydroxide aqueous solution and hydrogen peroxide solution) and ultrapure water L2 to the inner tank 21. As a result, the chemical liquid L1 and the ultrapure water L2 are mixed in the inner tank 21 to generate the processing liquid L. Alternatively, for example, the processing liquid L may be generated by mixing the chemical liquid L1 and the ultrapure water L2 with each other before they are supplied to the inner tank 21, and the processing liquid L may be supplied to the inner tank 21.

[0062] When the processing liquid L supplied to the inner tank 21 overflows from the inner tank 21, the overflowing processing liquid L is stored in the outer tank 22. In step S1, the processing liquid L is supplied until a sufficient amount of processing liquid L for etching the sample substrate Wa is stored in the inner tank 21 and the outer tank 22.

[0063] In step S1, the controller Ctr controls the pump 42 to circulate the treatment liquid L from the outer bath 22 to the inner bath 21 through the circulation path 41. The controller Ctr controls the pump 42 to transport the treatment liquid L from the outer bath 22 to the inner bath 21 through the circulation path 41 and to the first measuring unit 46 through the branch path 45. As the treatment liquid L circulates through the circulation path 41, the treatment liquid L passes through the second measuring unit 48. At this point, the controller Ctr controls the valve 47a to close the branch path 47. The first measuring unit 46 measures the silicon concentration of the treatment liquid L and transmits the measured value of the silicon concentration to the controller Ctr. The second measuring unit 48 measures the concentration of the mixed liquid and transmits the measured value of the concentration of the mixed liquid to the controller Ctr.

[0064] Next, the number of layers of the sample substrate Wm is input (step S2). For example, the operator inputs the number of layers of the sample substrate Wm prepared in step S1 via an external input device. The controller Ctr acquires the input number of layers of the sample substrate Wm.

[0065] Next, the controller Ctr acquires the pre-processing concentration of the processing liquid L (step S3). In step S3, the controller Ctr acquires the pre-processing concentration from the first measuring unit 46.

[0066] Next, the controller Ctr processes the sample substrates Wm (step S4). In step S4, the sample substrates Wm are etched. First, the controller Ctr controls the lot formation unit 3, and the transport mechanism 3a forms one lot from a plurality of sample substrates Wm and places the one lot on the pre-processing lot mounting table 4b. At this time, the lot formation unit 3 obtains the number of sample substrates Wm removed from the carrier 6 and transmits data on this number to the controller Ctr. Based on the received data, the controller Ctr calculates the number of sample substrates Wm formed into one lot in the lot formation unit 3.

[0067] Next, controller Ctr controls transport mechanism 7, holder 7c takes out the one lot from pre-processing lot mounting table 4b, and movable body 7b transports the one lot together with holder 7c to liquid processing apparatus 10. At this time, holder 7c hands over the one lot to holding member 31, which is in the raised position.

[0068] Next, the controller Ctr controls the holding unit 30 to move the holding member 31 from the raised position to the lowered position, whereby the plurality of sample substrates Wm held by the holding member 31 are immersed in the processing solution L in the inner bath 21, and the silicon nitride films W3 provided on the sample substrates Wm are etched.

[0069] Next, the controller Ctr determines whether a predetermined processing time has elapsed. If the controller Ctr determines that the predetermined processing time has elapsed, the controller Ctr controls the holding unit 30 to move the holding member 31 from the lowered position to the raised position. This completes the etching process for the plurality of sample substrates Wm held by the holding member 31. The etching process for the plurality of sample substrates Wm continues until the controller Ctr determines that the predetermined processing time has elapsed.

[0070] Next, the controller Ctr acquires the post-processing concentration of the processing liquid L (step S5). In step S5, the controller Ctr acquires the post-processing concentration from the first measuring unit 46.

[0071] Next, the controller Ctr calculates the amount of change in silicon concentration (step S6). In step S6, the controller Ctr calculates the amount of change in silicon concentration by subtracting the pre-processing concentration obtained in step S3 from the post-processing concentration obtained in step S5.

[0072] Subsequently, the controller Ctr generates each piece of data (step S7). In step S7, the controller Ctr changes the number of sample substrates Wm constituting one lot, and then repeatedly executes the same processes as steps S2 to S6. As a result, a plurality of first data are obtained that indicate the correspondence between the stacked number of sample substrates Wm acquired in step S2, the number of sample substrates Wm calculated in step S4, and the amount of change in silicon concentration calculated in step S5.

[0073] Next, the controller Ctr performs the same processes as steps S2 to S7 on the sample substrate Wn, thereby obtaining a plurality of second data indicating the correspondence between the number of stacked layers in the sample substrate Wn, the number of sample substrates Wn, and the amount of change in silicon concentration.

[0074] Next, the controller Ctr generates first correlation data (step S8). As shown in FIG. 5, in step S8, the first data and second data generated in step S7 are plotted on a graph. In the example of FIG. 5, three pieces of first data P1, P2, and P3 and three pieces of second data Q1, Q2, and Q3 are plotted on the graph. Next, an approximation line D1 is calculated based on the first data P1, P2, and P3, for example, by the least squares method, and an approximation line D2 is calculated based on the second data Q1, Q2, and Q3, for example, by the least squares method. As a result, an approximation line D1 correlating the number of sample substrates Wm, the number of layers of the sample substrates Wm, and the amount of change in silicon concentration, and an approximation line D2 correlating the number of sample substrates Wn, the number of layers of the sample substrates Wn, and the amount of change in silicon concentration, are calculated. Through the above process, generation of the first correlation data is completed. The controller Ctr stores the generated first correlation data in the memory unit M2. The approximation lines D1 and D2 may each be a straight line or a curved line.

[0075] [Processing for Generating Second Correlation Data] Next, processing for generating second correlation data will be described. As shown in Fig. 10, first, preparation for generating second correlation data is performed (step S11). Next, the number of stacked layers of the sample substrate Wm is input (step S12). In steps S11 and S12, processing similar to steps S1 and S2 is performed, respectively.

[0076] Next, the film thickness of the polysilicon film W5 on the sample substrate Wm before the etching process is measured (step S13). In step S13, for example, an operator may measure the film thickness of the polysilicon film W5 on the sample substrate Wm using a film thickness meter or the like. The operator inputs the film thickness of the polysilicon film W5 before the etching process via an external input device. The controller Ctr acquires the input film thickness of the polysilicon film W5 before the etching process.

[0077] Next, the controller Ctr processes the sample substrate Wm (step S14). Next, the controller Ctr acquires the post-processing concentration of the processing liquid L (step S15). In steps S14 and S15, the same processes as in steps S4 and S5 are executed, respectively.

[0078] Subsequently, the thickness of the polysilicon film W5 on the sample substrate Wm after the etching process is measured in the same manner as in step S13 (step S16). In step S16, for example, an operator inputs the thickness of the polysilicon film W5 on the sample substrate Wm after the etching process via an external input device. The controller Ctr acquires the input thickness of the polysilicon film W5 after the etching process.

[0079] Subsequently, the controller Ctr calculates the etching rate (step S17). The controller Ctr calculates a film thickness difference by subtracting the film thickness of the polysilicon film W5 after the etching process, which was acquired in step S16, from the film thickness of the polysilicon film W5 before the etching process, which was acquired in step S13. The controller Ctr calculates the etching rate by dividing the calculated film thickness difference by the processing time.

[0080] Next, the controller Ctr generates each piece of data (step S18). In step S18, the controller Ctr repeatedly executes the same processes as steps S13 to S17. By etching the plurality of sample substrates Wm in step S14, the polysilicon film W5 contained in the sample substrates Wm dissolves in the processing liquid L, thereby increasing the silicon concentration of the processing liquid L. In other words, the silicon concentration of the processing liquid L in the processing bath 20 increases each time the plurality of sample substrates Wm constituting one lot are etched. As a result, in step S18, a plurality of third data items are obtained that indicate the correspondence between the post-processing concentrations obtained in step S15 and the etching rates calculated in step S17.

[0081] Subsequently, the controller Ctr generates second correlation data (step S19). As shown in FIG. 6, in step S19, the third data generated in step S18 is plotted on a graph. In the example of FIG. 6, five third data P4, P5, P6, P7, and P8 are plotted on the graph. Next, an approximation line D3 is calculated, for example, by the least squares method, based on the third data P4, P5, P6, P7, and P8. As a result, an approximation line D3 that correlates the post-processing concentration of the sample substrate Wm with the etching rate of the sample substrate Wm is calculated. Through the above process, generation of the second correlation data is completed. The controller Ctr stores the generated second correlation data in the memory unit M2. Note that the approximation line D3 may be a curve or a straight line.

[0082] [Generation Process of Third Correlation Data] Next, the process of generating the third correlation data will be described. As shown in FIG. 11 , first, preparations for generating the third correlation data are made (step S21). Next, the number of layers of the sample substrate Wm is input (step S22). Next, the controller Ctr acquires the pre-processing concentration of the processing liquid L (step S23). Next, the controller Ctr processes the sample substrate Wm (step S24). Next, the controller Ctr acquires the post-processing concentration of the processing liquid L (step S25). Next, the controller Ctr calculates the amount of change in silicon concentration (step S26). In steps S21 to S26, the same processes as in steps S1 to S6 are executed, respectively.

[0083] Subsequently, the controller Ctr generates each piece of data (step S27). In step S27, the controller Ctr changes the processing time of the sample substrate Wm in step S24, and then repeatedly executes the same processes as steps S22 to S26. As a result, a plurality of fourth data are obtained that indicate the correspondence between the number of stacked layers of the sample substrate Wm acquired in step S22, the processing time of the sample substrate Wm in step S24, and the amount of change in silicon concentration calculated in step S26.

[0084] Next, the controller Ctr performs the same processes as steps S22 to S27 on the sample substrate Wn, thereby obtaining a plurality of fifth data items indicating the correspondence between the number of layers of the sample substrate Wn, the processing time of the sample substrate Wn, and the amount of change in silicon concentration.

[0085] Next, the controller Ctr generates third correlation data (step S28). As shown in FIG. 7, in step S28, the fourth data and the fifth data generated in step S27 are plotted on a graph. In the example of FIG. 7, an approximation line D4 is calculated, for example, by the least squares method, based on the three fourth data P9, P10, and P11, and an approximation line D5 is calculated, for example, by the least squares method, based on the fifth data Q9, Q10, and Q11. As a result, an approximation line D4 correlating the number of layers of the sample substrate Wm, the processing time of the sample substrate Wm, and the amount of change in silicon concentration, and an approximation line D5 correlating the number of layers of the sample substrate Wn, the processing time of the sample substrate Wn, and the amount of change in silicon concentration are calculated. Through the above process, generation of the third correlation data is completed. The controller Ctr stores the generated third correlation data in the memory unit M2. Note that the approximation lines D4 and D5 may each be a straight line or a curve.

[0086] The processes for generating the first correlation data, the second correlation data, and the third correlation data have been described above, but these processes may be executed independently or simultaneously. Note that "executing simultaneously" means that common steps in at least two of these processes are executed only once, without being executed redundantly.

[0087] [Substrate Processing Method] Next, the etching process of the substrate processing system 1 will be described with reference to Fig. 12. Before the substrate processing system 1 performs the etching process, the controller Ctr supplies the processing liquid L to the processing tank 20. The controller Ctr controls the valves 51b, 53b, and 55b to open each valve, thereby supplying the chemical liquid L1 and the ultrapure water L2 to the inner tank 21. As a result, the chemical liquid L1 and the ultrapure water L2 are mixed to generate the processing liquid L. At this time, the processing liquid L is supplied until a sufficient amount of the processing liquid L for etching the substrate W is stored in the inner tank 21 and the outer tank 22.

[0088] Before the substrate processing system 1 performs an etching process, the controller Ctr controls the pump 42 to circulate the processing liquid L from the outer bath 22 to the inner bath 21 through the circulation path 41. The controller Ctr controls the pump 42 to transport the processing liquid L from the outer bath 22 to the inner bath 21 through the circulation path 41 and to the first measuring unit 46 through the branch path 45. While the processing liquid L circulates through the circulation path 41, the processing liquid L passes through the second measuring unit 48. At this point, the controller Ctr controls the valve 47a to close the branch path 47. The first measuring unit 46 measures the silicon concentration of the processing liquid L and transmits the measured value of the silicon concentration to the controller Ctr. The second measuring unit 48 measures the concentration of the mixed liquid and transmits the measured value of the mixed liquid concentration to the controller Ctr.

[0089] Subsequently, the controller Ctr acquires a value relating to the amount of polysilicon (step S31). In step S31, for example, the operator inputs the number of layers of the substrate W as the value relating to the amount of polysilicon. The operator inputs the number of layers of the substrate W via an external input device. The controller Ctr acquires the input number of layers of the substrate W.

[0090] Next, in step S31, the controller Ctr controls the lot formation unit 3, and the transport mechanism 3a forms one lot from a plurality of substrates W and places the one lot on the pre-treatment lot mounting table 4b. At this time, the lot formation unit 3 obtains the number of substrates W removed from the carrier 6 and transmits data on this number to the controller Ctr. Based on the received data, the controller Ctr calculates the number of substrates W formed into one lot in the lot formation unit 3. The controller Ctr obtains the calculated number of substrates W as a value related to the amount of polysilicon.

[0091] Furthermore, in step S31, for example, the operator inputs, via an external input device, the etching amount of the substrate W. The controller Ctr acquires the input etching amount of the substrate W.

[0092] Next, the controller Ctr acquires the pre-processing concentration of the processing liquid L (step S32). In step S32, the same process as in step S3 is executed.

[0093] Next, the controller Ctr determines whether the pre-processing concentration of the processing liquid L obtained in step S32 is less than a predetermined value (step S33). The controller Ctr executes step S33 before executing step S52, which will be described later. If the controller Ctr determines that the pre-processing concentration is equal to or greater than the predetermined value (NO in step S33), the controller Ctr executes a processing liquid replacement process (step S34). If the controller Ctr determines that the pre-processing concentration is less than the predetermined value (YES in step S33), the controller Ctr executes a processing time determination process (step S35).

[0094] The processing liquid replacement process will now be described in detail with reference to Fig. 13. The processing liquid replacement process is a process for adjusting the silicon concentration of the processing liquid L to be less than a predetermined value. First, the controller Ctr calculates the discharge amount of the processing liquid L (step S41). Based on the pre-processing concentration acquired in step S32 and the preset capacity of the processing tank 20, the controller Ctr calculates the discharge amount required to make the silicon concentration of the processing liquid L less than the predetermined value.

[0095] Next, the controller Ctr calculates the supply amount of the treatment liquid L (step S42). The controller Ctr calculates the supply amount of the treatment liquid L to be, for example, an amount equal to the discharge amount calculated in step S41.

[0096] Next, the controller Ctr controls the discharge unit 60 and the supply unit 50 (step S43). The controller Ctr controls the valve 62 to open the valve 62, thereby discharging the processing liquid L in the inner bath 21 through the discharge path 61 to the outside of the substrate processing system 1. The controller Ctr discharges the processing liquid L at the discharge amount calculated in step S41 to the outside of the substrate processing system 1.

[0097] Next, the controller Ctr controls the valves 52b, 54b, and 56b to open the valves, thereby supplying the chemical liquid L1 and the ultrapure water L2 to the outer bath 22. The controller Ctr supplies the processing liquid L at the supply amount calculated in step S42 to the outer bath 22. The processing liquid L supplied to the outer bath 22 is supplied to the inner bath 21 through the circulation path 41. After the above processing, the controller Ctr ends the processing liquid replacement processing.

[0098] Next, the processing time determination process will be described in detail with reference to Fig. 14. The processing time determination process is a process for determining the processing time of substrates W constituting one lot. First, the controller Ctr estimates the amount of change in silicon concentration (step S51). The controller Ctr estimates the amount of change in silicon concentration of the substrate W after the etching process based on the value related to the amount of polysilicon acquired in step S31 and the first correlation data generated in step S8.

[0099] When estimating the amount of change in silicon concentration, first, the controller Ctr identifies an approximation line to reference in the first correlation data based on the number of stacked substrates W acquired in step S31. In the example of Fig. 5 , the controller Ctr acquires a value of M stages as the number of stacked substrates W and identifies approximation line D1 as the approximation line to reference. Next, the controller Ctr identifies an amount of change in silicon concentration corresponding to the number of substrates W acquired in step S31. In the example of Fig. 5 , the controller Ctr acquires a value of X1 as the number of substrates W and identifies a value Y1 as the amount of change in silicon concentration based on the approximation line D1. The controller Ctr estimates the identified amount of change in silicon concentration as the amount of change in silicon concentration of the substrates W after the etching process.

[0100] Next, the controller Ctr estimates the post-processing concentration of the processing liquid L based on the value related to the amount of polysilicon acquired in step S31 and the pre-processing concentration acquired in step S32 (step S52). More specifically, the controller Ctr estimates the post-processing concentration of the processing liquid L as the sum of the change in silicon concentration estimated in step S51 and the pre-processing concentration acquired in step S32.

[0101] The post-processing concentration of the processing solution L is determined by the parameters x and c ０ , A, B, c respectively x: the number of substrates W constituting one lot c ０ : concentration before processing, A and B: constants determined by the number of layers and film type of the substrate W, and c: concentration after processing, the concentration may be calculated based on the following formula (3): c=Ax+B+c ０ ... (3)

[0102] Subsequently, the controller Ctr determines the processing time for the substrate W in the processing bath 20 based on the second correlation data generated in step S19 and the post-processing concentration of the processing liquid L estimated in step S52 (step S53).

[0103] In determining the processing time for the substrate W, the controller Ctr first identifies, in the second correlation data, the etching rate corresponding to the post-processing concentration estimated in step S52. In the example of Fig. 6, the controller Ctr estimates the value of Y1 as the amount of change in silicon concentration in step S51, and estimates the value of X3 (= 0 + Y1), which is the sum of the pre-processing concentration (0) and the amount of change in silicon concentration (Y1), as the post-processing concentration. The controller Ctr then identifies the value of Y3 as the etching rate based on the approximation line D3. The controller Ctr determines the processing time by dividing the etching amount of the substrate W acquired in step S31 by the identified etching rate. After the above processing, the controller Ctr terminates the processing time determination process.

[0104] For example, after etching substrates W constituting one lot, etching may be performed on substrates W constituting a subsequent lot. In the example of Fig. 5 , in step S51, the controller Ctr obtains the value M as the number of stacked substrates W and identifies the approximation line D1 as a reference approximation line. Next, the controller Ctr obtains the value X2 as the number of substrates W and identifies the value Y2 as the amount of change in silicon concentration based on the approximation line D1. As shown in Fig. 6 , in step S52, the controller Ctr estimates the value X4 (=X3+Y2), which is the sum of the pre-processing concentration (X3) and the amount of change in silicon concentration (Y2), as the post-processing concentration. Then, in step S53, the controller Ctr identifies the value Y4 as the etching rate based on the approximation line D3.

[0105] The processing time of the substrate W may be calculated based on the following formulas (4) and (5), where C, D, E, r, a, and t are defined as follows: C, D, and E are constants determined by the number of layers and the type of film on the substrate W; r is the etching rate of the substrate W; a is the amount of etching on the substrate W; and t is the processing time. ２ -Dc+E... (4) t=a / r... (5)

[0106] Subsequently, the controller Ctr starts the processing of the substrate W (step S36). First, the controller Ctr controls the transport mechanism 7 so that the holder 7c takes out the one lot from the unprocessed lot mounting table 4b, and the movable body 7b transports the one lot together with the holder 7c to the liquid processing apparatus 10. At this time, the holder 7c hands over the one lot to the holding member 31, which is in the raised position.

[0107] Next, the controller Ctr controls the holding unit 30 to move the holding members 31 from the raised position to the lowered position, whereby the substrates W held by the holding members 31 are immersed in the processing liquid L in the inner bath 21, and the polysilicon films W5 provided on the substrates W are etched.

[0108] 15, the controller CTr first determines whether a predetermined time has elapsed since the controller CTr started the etching process of the substrate W in step S36 (step S61). If the controller CTr determines that the predetermined time has not elapsed (NO in step S61), the etching process of the substrate W continues until the controller CTr determines that the predetermined time has elapsed.

[0109] For example, the controller Ctr may determine the predetermined time to be a time shorter than the processing time determined in step S35 (see FIG. 12). Hereinafter, for convenience of explanation, the predetermined time may be referred to as a "corrected determination time."

[0110] When the controller Ctr determines that the correction determination time has elapsed (YES in step S61), the controller Ctr acquires the silicon concentration of the treatment liquid L in the treatment tank 20 (step S62). The controller Ctr acquires the silicon concentration of the treatment liquid L by performing a process similar to the process in step S3. Next, the controller Ctr calculates the difference between the pre-treatment concentration acquired in step S32 and the silicon concentration acquired in step S62 (step S63).

[0111] Next, the controller Ctr estimates the amount of change in silicon concentration of the processing liquid L when the substrate W is etched for the corrected judgment time based on the third correlation data and the corrected judgment time (step S64). The controller Ctr identifies the amount of change in silicon concentration corresponding to the corrected judgment time in the third correlation data. The controller Ctr estimates the identified amount of change in silicon concentration as the amount of change in silicon concentration of the processing liquid L when the substrate W is etched for the corrected judgment time.

[0112] Next, the controller Ctr determines whether the difference between the difference amount calculated in step S63 and the change amount estimated in step S64 is outside a predetermined range (step S65). First, the controller Ctr calculates a value by subtracting the estimated change amount from the difference amount calculated by the controller Ctr. Next, the controller Ctr determines whether the calculated value is equal to or greater than a predetermined first value and equal to or less than a predetermined second value. For example, the first value is a negative value, and the second value is a positive value.

[0113] When the controller Ctr determines that the calculated value is not equal to or greater than the first value and equal to or less than the second value, the controller Ctr determines that the difference between the difference amount and the change amount is outside a predetermined range, and when the controller Ctr determines that the calculated value is equal to or greater than the first value and equal to or less than the second value, the controller Ctr determines that the difference between the difference amount and the change amount is within a predetermined range.

[0114] When the controller CTr determines that the difference between the differential amount and the change amount is within a predetermined range (NO in step S65), the controller CTr terminates the processing time correction process.When the controller CTr determines that the difference between the differential amount and the change amount is outside the predetermined range (YES in step S65 of FIG. 15), the controller CTr corrects the processing time of the substrate W (step S66).

[0115] In step S66, the controller Ctr corrects the processing time so that the value obtained by subtracting the amount of change from the amount of difference is equal to or greater than a first value and equal to or less than a second value. For example, if the controller Ctr determines that the value is smaller than the first value, the estimated amount of change is greater than the calculated amount of difference (the amount of change in the silicon concentration that has actually occurred) by more than a predetermined range. Therefore, the controller Ctr corrects the processing time to a time longer than the processing time determined in step S35. For example, if the controller Ctr determines that the value is greater than the second value, the estimated amount of change is smaller than the calculated amount of difference by more than a predetermined range. Therefore, the controller Ctr corrects the processing time to a time shorter than the processing time determined in step S35. After the above processing, the controller Ctr terminates the processing time correction processing.

[0116] Next, the controller Ctr determines whether a predetermined processing time has elapsed. If the controller Ctr determines that the predetermined processing time has elapsed, the controller Ctr terminates the processing of the substrates W (step S38 in FIG. 12 ). In step S38, the controller Ctr controls the holder 30 to move the holding members 31 from the lowered position to the raised position. This completes the etching processing of the multiple substrates W held by the holding members 31. The controller Ctr continues the etching processing of the substrates W until the controller Ctr determines that the predetermined processing time has elapsed.

[0117] Next, the controller Ctr determines whether a predetermined termination condition has been met (step S39). The termination condition is, for example, that the controller Ctr has received a termination command to terminate the processing. For example, an operator inputs a termination command to the controller Ctr via an external input device. If the termination command has been input, the controller Ctr determines that the termination condition has been met. If the termination command has not been input, the controller Ctr determines that the termination condition has not been met.

[0118] If the controller Ctr determines that the termination condition is satisfied (YES in step S39), the substrate processing system 1 terminates the series of etching processes. If the controller Ctr determines that the termination condition is not satisfied (NO in step S39), the controller Ctr executes step S31 again.

[0119] After the substrate processing system 1 finishes the etching process, the controller Ctr controls the pump 42 to stop the circulation of the processing liquid L. Thereafter, the controller Ctr controls the valve 47a to open the branch path 47. As a result, the controller Ctr discharges the processing liquid L remaining in the circulation path 41 to the outside of the substrate processing system 1 through the branch path 47.

[0120] Next, the mixed liquid concentration adjustment process will be described in detail with reference to Fig. 16. The mixed liquid concentration adjustment process is a process for adjusting the concentration of the mixed liquid in the processing tank 20 so that it falls within a predetermined range. The mixed liquid concentration adjustment process is performed, for example, while the substrate processing system 1 is in operation. The mixed liquid concentration adjustment process may be performed, for example, at a timing selected by the operator, or may be performed every time processing of one lot is completed.

[0121] First, the controller Ctr acquires the concentration of the mixed liquid from the second measuring unit 48 (step S71).

[0122] Next, the controller Ctr determines whether the concentration of the mixed liquid acquired in step S71 is outside a predetermined range (step S72). The controller Ctr determines whether the concentration of the mixed liquid is equal to or greater than a predetermined third value and equal to or less than a predetermined fourth value. If the controller Ctr determines that the concentration of the mixed liquid is equal to or greater than the third value and equal to or less than the fourth value, the controller Ctr determines that the concentration of the mixed liquid is not outside the predetermined range. If the controller Ctr determines that the concentration of the mixed liquid is not equal to or greater than the third value and equal to or less than the fourth value, the controller Ctr determines that the concentration of the mixed liquid is outside the predetermined range.

[0123] If the controller Ctr determines that the concentration of the mixed liquid is not outside the predetermined range (NO in step S72), the controller Ctr ends the mixed liquid concentration adjustment process. If the controller Ctr determines that the concentration of the mixed liquid is outside the predetermined range (YES in step S72), the controller Ctr calculates the discharge amount of the treatment liquid L (step S73). In step S73, the controller Ctr calculates the discharge amount necessary to bring the concentration of the mixed liquid within the predetermined range based on the concentration of the mixed liquid acquired in step S71 and the capacity of the treatment tank 20.

[0124] Next, the controller Ctr calculates the supply amount of at least one of the chemical liquid L1 and the ultrapure water L2 (step S74). In step S74, the controller Ctr calculates, for example, the supply amount of at least one of the chemical liquid L1 and the ultrapure water L2 necessary to bring the concentration of the mixed liquid within a predetermined range. For example, if the controller Ctr determines that the concentration of the mixed liquid is less than a third value, the controller Ctr calculates the supply amount of the chemical liquid L1 necessary to bring the concentration of the mixed liquid to the third value or more. For example, if the controller Ctr determines that the concentration of the mixed liquid is greater than a fourth value, the controller Ctr calculates the supply amount of the ultrapure water L2 necessary to bring the concentration of the mixed liquid to the fourth value or less.

[0125] Next, the controller Ctr controls the discharge unit 60 and the supply unit 50 (step S75). The controller Ctr controls the valve 62 to open the valve 62, thereby discharging the processing liquid L in the inner bath 21 through the discharge path 61 to the outside of the substrate processing system 1. The controller Ctr discharges the processing liquid L at the discharge amount calculated in step S73 to the outside of the substrate processing system 1.

[0126] Next, the controller Ctr controls at least one of the valves 52b, 54b, and 56b to open each valve, thereby supplying at least one of the chemical liquid L1 and the ultrapure water L2 to the outer bath 22. The controller Ctr supplies at least one of the chemical liquid L1 and the ultrapure water L2 in the supply amount calculated in step S74 to the outer bath 22. After the above processing, the controller Ctr ends the mixed solution concentration adjustment processing.

[0127] [Function] When a substrate W is etched in the processing tank 20, polysilicon contained in the substrate W dissolves in the processing liquid L, increasing the silicon concentration of the processing liquid L in the processing tank 20. The increase in silicon concentration in the processing liquid L reduces the etching rate of the substrate W during the etching process. Therefore, if a substrate W is etched using the processing liquid L in the processing tank 20 and then a subsequent substrate W is etched without replacing the processing liquid L, a difference will occur between the amount of etching of the substrate W and the amount of etching of the subsequent substrate W. As a result, the amount of etching of the substrate W may vary depending on the timing of the etching process of the substrate W. It is conceivable to replace the processing liquid L in the processing tank 20 every time a substrate W is etched, but replacing the processing liquid L may reduce work efficiency.

[0128] However, according to the above example, the substrate processing system 1 estimates the post-processing concentration based on the value relating to the amount of polysilicon contained in the substrate W and the pre-processing concentration. This system estimates an etching rate corresponding to the estimated post-processing concentration and determines the processing time for the substrate W according to the estimated etching rate. Therefore, etching can be performed according to the determined processing time. This reduces the possibility of variations in the etching amount of the substrate W, even when etching a substrate W consecutively without replacing the processing liquid L after the etching processing of the substrate W. Therefore, work efficiency can be improved while suppressing variations in the etching amount of the substrate W. Furthermore, since the frequency of replacing the processing liquid L can be reduced, the amount of processing liquid L used and the amount of waste can be reduced. This reduces the cost required for etching.

[0129] According to the above example, the process for estimating the post-processing concentration includes a process for estimating the change in silicon concentration of the processing liquid L in the processing tank 20 after the etching process of the substrate W based on first correlation data indicating the correlation between a value relating to the amount of polysilicon contained in the sample substrate Wa and the change in silicon concentration of the processing liquid L after the etching process of the sample substrate Wa, and a value relating to the amount of polysilicon in the substrate W, and a process for estimating the sum of the estimated change and the pre-processing concentration as the post-processing concentration. In this case, the post-processing concentration can be estimated more accurately because the first correlation data generated in advance by conducting an experiment using the sample substrate Wa can be used to estimate the change in silicon concentration, and the post-processing concentration can be estimated by a simple calculation because the change in silicon concentration is estimated using the value relating to the amount of polysilicon and the first correlation data, and the sum of the estimated change and the pre-processing concentration is estimated as the post-processing concentration. As a result, the post-processing concentration can be estimated more accurately and simply.

[0130] In the above example, the substrate W includes a plurality of layers W1. Each of the plurality of layers W1 includes polysilicon. The value relating to the amount of polysilicon includes the number of substrates W simultaneously processed in the processing tank 20 and the number of layers W1 stacked on the substrates W. It is believed that the number of substrates W simultaneously processed in the processing tank 20 and the number of layers W1 stacked on the substrates W each have a correlation with the amount of polysilicon contained in the substrates W. Therefore, by using the number of substrates W and the number of layers as the value relating to the amount of polysilicon contained in the substrates W, the post-processing concentration can be more easily estimated.

[0131] According to the above example, the controller Ctr is further configured to calculate the difference between the silicon concentration of the processing liquid L in the processing bath 20 and the pre-processing concentration after a predetermined time (correction determination time) has elapsed since the start of etching the substrate W; estimate the change in silicon concentration of the processing liquid L when the substrate W is etched for a predetermined time based on third correlation data indicating the correlation between the processing time of the sample substrate Wa and the change in silicon concentration of the processing liquid L after etching the sample substrate Wa, and the predetermined time; and correct the processing time so that the difference between the calculated difference and the estimated change falls within a predetermined range. In this case, the difference between the difference in silicon concentration actually produced by etching the substrate W for the predetermined time and the change in silicon concentration estimated based on the third correlation data and the predetermined time is calculated. Since the processing time of the substrate W is corrected so that the calculated difference falls within the predetermined range, if the estimated change deviates from the calculated difference by more than a predetermined amount, the processing time can be corrected to adjust the etching amount of the substrate W. As a result, variation in the etching amount of the substrate W is further suppressed.

[0132] According to the above example, the substrate processing system 1 further includes a discharge unit 60 configured to discharge the processing liquid L in the processing tank 20 to the outside of the processing tank 20, and a supply unit 50 configured to supply the processing liquid L to the processing tank 20. The controller Ctr is further configured to execute the following processes before estimating the post-processing concentration: determining whether the pre-processing concentration is equal to or greater than a predetermined value; and, if it is determined that the pre-processing concentration is equal to or greater than the predetermined value, controlling the discharge unit 60 and the supply unit 50 so that the silicon concentration of the processing liquid L is less than the predetermined value. In this case, the silicon concentration of the processing liquid L can be prevented from becoming excessively high due to repeated etching of the substrate W. Therefore, the etching of the substrate W is prevented from becoming extremely slow, and the etching process can be completed within a predetermined time.

[0133] According to the above example, the substrate processing system 1 further includes a second measuring unit 48, a discharge unit 60 configured to discharge the processing liquid L in the processing tank 20 to the outside of the processing tank 20, and a supply unit 50. The processing liquid L is a mixture of ultrapure water L2 and at least one chemical liquid L1. The second measuring unit 48 is configured to measure the concentration of the mixture. The supply unit 50 is configured to supply at least one of the ultrapure water L2 and the chemical liquid L1 to the processing tank 20. The controller Ctr is further configured to execute a process of controlling the discharge unit 60 and the supply unit 50 based on the concentration of the mixture so that the concentration of the mixture falls within a predetermined range. In this case, the concentration of the mixture in the processing tank 20 can be maintained within the predetermined range. This makes it possible to further suppress variations in the etching amount of the substrates W.

[0134] According to the above example, the first measuring unit 46 is configured to continuously measure the silicon concentration of the processing liquid L over time. In this case, since the silicon concentration of the processing liquid L is continuously measured, the processing time of the substrate W can be changed immediately in response to changes in the silicon concentration. Therefore, it becomes possible to determine whether the silicon concentration changes more than expected during processing of the substrate W with the processing liquid L.

[0135] [Modifications] The disclosure in this specification should be considered to be illustrative in all respects and not restrictive. Various omissions, substitutions, modifications, etc. may be made to the above examples without departing from the scope and spirit of the claims.

[0136] (1) The controller Ctr estimates the amount of change in silicon concentration based on the value related to the amount of polysilicon and the first correlation data, and estimates the post-processing concentration as the sum of the estimated amount of change and the pre-processing concentration. However, the controller Ctr may estimate the post-processing concentration using any known means.

[0137] (2) The processing liquid L may be an alkaline processing liquid other than the SC-1 liquid, the NC-2 liquid, and TMAH.

[0138] (3) As illustrated in FIG. 12 , the controller Ctr executes step S31 and then step S32. However, the controller Ctr may execute step S31 while executing steps S32 to S34. This allows the operator to input a value related to the amount of polysilicon while at least one of steps S32 to S34 is being executed. As a result, the time required from etching the substrates W constituting one lot to etching the substrates W constituting the subsequent lot can be shortened. This can improve the operating rate of the substrate processing system 1.

[0139] (4) As illustrated in Fig. 13 , in the liquid treatment exchange process, the controller Ctr calculates the discharge amount of the treatment liquid L in step S41 and controls the discharge unit 60 to discharge the treatment liquid L at the calculated discharge amount in step S41. However, the controller Ctr may discharge all of the treatment liquid L from the treatment tank 20 based on a preset capacity of the treatment tank 20. In this case, in step S42, the controller Ctr may control the supply unit 50 to supply the treatment liquid L to the treatment tank 20 in an amount equal to the discharge amount calculated in step S41.

[0140] (5) As illustrated in Figures 5 to 7, the first correlation data, second correlation data, and third correlation data are data expressed as two-axis graphs. However, the first correlation data may be data showing the correlation between a value related to the amount of polysilicon and the amount of change in silicon concentration. The second correlation data may be data showing the correlation between the post-processing concentration and the etching rate. The third correlation data may be data showing the correlation between processing time and the amount of change in silicon concentration.

[0141] (6) The controller Ctr calculated the number of substrates W constituting one lot based on the data on the number of substrates W transmitted from the lot formation unit 3. However, for example, the operator may input the number of substrates W via an external input device. In this case, in step S31, the controller Ctr obtains the input number of substrates W as a value related to the amount of polysilicon.

[0142] [Other Examples] Example 1. An example of a substrate processing apparatus is configured to etch a substrate containing polysilicon using an alkaline processing liquid. The example of the substrate processing apparatus includes a processing tank configured to etch the substrate with the processing liquid, a measurement unit configured to measure the silicon concentration of the processing liquid, and a control unit. The control unit is configured to execute the following processes: a process of estimating a post-processing concentration, which is the silicon concentration of the processing liquid in the processing tank after etching the substrate, based on a value related to the amount of polysilicon contained in the substrate and a pre-processing concentration, which is the silicon concentration of the processing liquid in the processing tank before etching the substrate, measured by the measurement unit; and a process of determining a processing time for the substrate in the processing tank based on correlation data indicating a correlation between the silicon concentration of the processing liquid in the processing tank after etching a sample substrate with the processing liquid in the processing tank and the etching rate of the sample substrate due to the etching process, and the estimated post-processing concentration.

[0143] When a substrate is etched in a processing tank, polysilicon contained in the substrate dissolves in the processing liquid, increasing the silicon concentration of the processing liquid in the processing tank. The increased silicon concentration in the processing liquid reduces the etching rate of the substrate during the etching process. Therefore, if a substrate is etched using the processing liquid in the processing tank and then a subsequent substrate is etched without changing the processing liquid, a difference will occur between the amount of etching of the substrate and the amount of etching of the subsequent substrate. As a result, the amount of etching of the substrate may vary depending on the timing of the substrate etching process. While it is conceivable to change the processing liquid in the processing tank every time a substrate is etched, changing the processing liquid may reduce work efficiency.

[0144] In the apparatus of Example 1, the post-processing concentration is estimated based on a value relating to the amount of polysilicon contained in the substrate and the pre-processing concentration. This apparatus estimates an etching rate according to the estimated post-processing concentration, and determines the substrate processing time according to the estimated etching rate. Therefore, etching can be performed according to the determined processing time. This reduces the possibility of variations in the etching amount of the substrate, even when etching a substrate and then subsequently etching a subsequent substrate without changing the processing liquid. Therefore, work efficiency can be improved while suppressing variations in the etching amount of the substrate. Furthermore, since the frequency of changing the processing liquid can be reduced, the amount of processing liquid used and the amount of waste can be reduced. Therefore, the cost required for etching can be reduced.

[0145] Example 2. In the apparatus of Example 1, the process of estimating the post-processing concentration may include a process of estimating the change in silicon concentration of the processing solution in the processing tank after etching the substrate based on a value related to the amount of polysilicon contained in the sample substrate and another correlation data showing the correlation between the value related to the amount of polysilicon and the change in silicon concentration of the processing solution after etching the sample substrate, and a process of estimating the sum of the estimated change and the pre-processing concentration as the post-processing concentration. In this case, for example, the post-processing concentration can be estimated using another correlation data generated in advance by conducting an experiment using the sample substrate, thereby enabling more accurate estimation of the post-processing concentration. Furthermore, the change in silicon concentration is estimated using the value related to the amount of polysilicon and the other correlation data, and the post-processing concentration is estimated by the sum of the estimated change and the pre-processing concentration, allowing the post-processing concentration to be estimated by a simple calculation. As described above, the post-processing concentration can be estimated more accurately and simply.

[0146] Example 3 In the apparatus of Example 1 or Example 2, the substrate may include multiple layers. Each of the multiple layers may include polysilicon. The value related to the amount of polysilicon may include the number of substrates simultaneously processed in the processing tank and the number of layers stacked on the substrate. The number of substrates simultaneously processed in the processing tank and the number of layers stacked on the substrate are each considered to be correlated with the amount of polysilicon contained in the substrate. Therefore, by using the number of substrates and the number of layers as the value related to the amount of polysilicon contained in the substrate, the post-processing concentration can be more easily estimated.

[0147] Example 4. In any of the apparatuses of Examples 1 to 3, the control unit may further perform the following operations: calculating a difference between the silicon concentration of the processing solution in the processing tank at a predetermined time after the start of etching the substrate and the pre-processing concentration; estimating a change in silicon concentration of the processing solution when the substrate is etched for a predetermined time based on additional correlation data indicating a correlation between the processing time of the sample substrate and the change in silicon concentration of the processing solution after etching the sample substrate, and the predetermined time; and correcting the processing time so that the difference between the calculated difference and the estimated change falls within a predetermined range. In this case, the difference between the difference in silicon concentration actually produced by performing the etching process for the predetermined time and the change in silicon concentration estimated based on the additional correlation data and the predetermined time is calculated. Since the processing time of the substrate is corrected so that the calculated difference falls within the predetermined range, if the estimated change deviates from the calculated difference by more than a predetermined amount, the processing time can be corrected to adjust the etching amount of the substrate. As a result, variation in the etching amount of the substrate is further suppressed.

[0148] Example 5. The apparatus of any of Examples 1 to 4 may further include a discharge unit configured to discharge the treatment liquid in the treatment tank to the outside of the treatment tank, and a supply unit configured to supply the treatment liquid to the treatment tank. The control unit may further execute the following processes before estimating the post-treatment concentration: determining whether the pre-treatment concentration is equal to or greater than a predetermined value; and, if it is determined that the pre-treatment concentration is equal to or greater than the predetermined value, controlling the discharge unit and the supply unit so that the silicon concentration of the treatment liquid is less than the predetermined value. In this case, the silicon concentration of the treatment liquid can be prevented from becoming excessively high due to repeated etching of the substrate. Therefore, the etching of the substrate is prevented from becoming extremely slow, allowing the etching process to be completed within a predetermined time.

[0149] Example 6. The apparatus of any of Examples 1 to 5 may further include another measuring unit, a discharge unit configured to discharge the processing liquid in the processing tank to the outside of the processing tank, and a supply unit. The processing liquid may be a mixed liquid of ultrapure water and at least one chemical liquid. The another measuring unit may be configured to measure the concentration of the mixed liquid. The supply unit may be configured to supply at least one of ultrapure water and the chemical liquid to the processing tank. The control unit may further be configured to execute a process of controlling the discharge unit and the supply unit based on the concentration of the mixed liquid so that the concentration of the mixed liquid falls within a predetermined range. In this case, the concentration of the mixed liquid in the processing tank can be maintained within the predetermined range. Therefore, it is possible to further suppress variation in the etching amount of the substrate.

[0150] Example 7. In any of the apparatuses of Examples 1 to 6, the measurement unit may be configured to continuously measure the silicon concentration of the treatment liquid over time. In this case, since the silicon concentration of the treatment liquid is continuously measured, the substrate treatment time can be changed immediately in response to changes in the silicon concentration. Therefore, it becomes possible to determine whether the silicon concentration changes more than expected during substrate treatment with the treatment liquid.

[0151] Example 8 In the apparatus of any of Examples 1 to 7, the treatment liquid may be an SC-1 liquid, which is a mixed liquid containing ammonium hydroxide, hydrogen peroxide, and ultrapure water; an NC-2 liquid, which is a mixed liquid containing choline, hydrogen peroxide, and ultrapure water; or a TMAH liquid, which is a mixed liquid containing tetramethylammonium hydroxide and ultrapure water.

[0152] Example 9 In the apparatus of any one of Examples 1 to 8, the temperature of the treatment liquid may be 40°C or higher and 80°C or lower.

[0153] Example 10. One example of a substrate processing method is a substrate processing method for etching a substrate containing polysilicon using an alkaline processing liquid stored in a processing tank. This example of the substrate processing method includes a first step of estimating a post-processing concentration, which is the silicon concentration of the processing liquid in the processing tank after etching the substrate, based on a value related to the amount of polysilicon contained in the substrate and a pre-processing concentration, which is the silicon concentration of the processing liquid in the processing tank before etching the substrate, measured by a measurement unit configured to measure the silicon concentration of the processing liquid; and a second step of determining a processing time for the substrate in the processing tank based on correlation data indicating a correlation between the silicon concentration of the processing liquid in the processing tank after etching a sample substrate with the processing liquid in the processing tank and the etching rate of the sample substrate due to the etching process, and the post-processing concentration estimated in the first step. In this case, the same effects as those of the apparatus of Example 1 can be obtained.

[0154] Example 11. In the method of Example 10, the first step may further include a third step of estimating a change in silicon concentration of the processing solution in the processing tank after the etching processing of the substrate based on a value relating to the amount of polysilicon contained in the sample substrate and another correlation data showing a correlation between the amount of polysilicon contained in the sample substrate and the amount of change in silicon concentration of the processing solution after the etching processing of the sample substrate, and a value relating to the amount of polysilicon in the substrate, and a fourth step of estimating a post-processing concentration as the sum of the amount of change estimated in the third step and the pre-processing concentration. In this case, the same effects as those of the apparatus of Example 2 can be obtained.

[0155] Example 12 In the method of Example 10 or Example 11, the substrate may include multiple layers. Each of the multiple layers may include polysilicon. The value related to the amount of polysilicon may include the number of substrates simultaneously processed in the processing tank and the number of layers stacked on the substrate. In this case, the same effects as those of the apparatus of Example 3 can be obtained.

[0156] Example 13. Any of the methods of Examples 10 to 12 may further include a fifth step of calculating a difference between the silicon concentration of the processing liquid in the processing tank at a predetermined time after the start of etching the substrate and the concentration before the processing, a sixth step of estimating a change in the silicon concentration of the processing liquid when the substrate is etched for a predetermined time based on further correlation data showing a correlation between the processing time of the sample substrate and the change in silicon concentration of the processing liquid after etching the sample substrate, and the predetermined time, and a seventh step of correcting the processing time so that the difference between the difference calculated in the fifth step and the change estimated in the sixth step falls within a predetermined range. In this case, the same effects as those of the apparatus of Example 4 can be obtained.

[0157] Example 14. Any of the methods of Examples 10 to 13 may further include, before the first step, an eighth step of determining whether the pre-treatment concentration is equal to or greater than a predetermined value, and a ninth step of controlling, if it is determined in the eighth step that the pre-treatment concentration is equal to or greater than the predetermined value, a discharge unit configured to discharge the treatment liquid in the treatment tank to the outside of the treatment tank and a supply unit configured to supply the treatment liquid to the treatment tank so that the silicon concentration of the treatment liquid becomes less than the predetermined value. In this case, the same effects as those of the apparatus of Example 5 can be obtained.

[0158] Example 15. Any of the methods of Examples 10 to 14 may further include a tenth step of measuring the concentration of a treatment liquid mixture, which is a mixture of ultrapure water and at least one chemical solution, and an eleventh step of controlling a discharge unit configured to discharge the treatment liquid in the treatment tank to the outside of the treatment tank and a supply unit configured to supply the treatment liquid to the treatment tank, based on the concentration of the mixture measured in step 10, so that the concentration of the mixture falls within a predetermined range. In this case, the same effects as those of the apparatus of Example 6 can be obtained.

[0159] Example 16 In any of the methods of Examples 10 to 15, the measuring unit may be configured to continuously measure the silicon concentration of the treatment liquid over time. In this case, the same effects as those of the device of Example 7 can be obtained.

[0160] Example 17 In the method of any of Examples 10 to 16, the treatment liquid may be an SC-1 liquid, which is a mixed liquid containing ammonium hydroxide, hydrogen peroxide, and ultrapure water; an NC-2 liquid, which is a mixed liquid containing choline, hydrogen peroxide, and ultrapure water; or a TMAH liquid, which is a mixed liquid containing tetramethylammonium hydroxide and ultrapure water.

[0161] Example 18 In any of the methods of Examples 10 to 17, the temperature of the treatment liquid may be 40°C or higher and 80°C or lower.

[0162] 1...substrate processing system (substrate processing apparatus), 20...processing tank, 46...first measurement unit (measurement unit), 48...second measurement unit (another measurement unit), 50...supply unit, 60...discharge unit, Ctr...controller (control unit), L...processing liquid, L1...chemical liquid, L2...ultrapure water, W...substrate, W1...layer, Wa, Wm, Wn...sample substrates.

Claims

1. A substrate processing apparatus configured to etch a substrate containing polysilicon using an alkaline processing liquid, comprising: a processing tank configured to etch the substrate with the processing liquid; a measurement unit configured to measure a silicon concentration of the processing liquid; and a control unit, wherein the control unit is configured to execute the following processes: a process of estimating a post-processing concentration, which is the silicon concentration of the processing liquid in the processing tank after the etching process of the substrate, based on a value related to the amount of polysilicon contained in the substrate and a pre-processing concentration, which is the silicon concentration of the processing liquid in the processing tank before the etching process of the substrate, measured by the measurement unit; and a process of determining a processing time for the substrate in the processing tank based on correlation data indicating a correlation between the silicon concentration of the processing liquid in the processing tank after a sample substrate has been etched in the processing tank with the processing liquid and an etching rate of the sample substrate by the etching process, and the estimated post-processing concentration.

2. The apparatus of claim 1, wherein the process of estimating the post-processing concentration includes a process of estimating an amount of change in the silicon concentration of the processing liquid in the processing tank after the etching process of the substrate based on another correlation data indicating a correlation between a value relating to the amount of polysilicon contained in the sample substrate and an amount of change in the silicon concentration of the processing liquid after the etching process of the sample substrate, and the value relating to the amount of polysilicon in the substrate; and a process of estimating the sum of the estimated amount of change and the pre-processing concentration as the post-processing concentration.

3. The apparatus of claim 1 or 2, wherein the substrate includes a plurality of layers, each of the plurality of layers includes the polysilicon, and the value relating to the amount of the polysilicon includes the number of the substrates simultaneously processed in the processing tank and the number of the plurality of layers stacked on the substrate.

4. The apparatus of claim 1 or 2, wherein the control unit is further configured to execute the following processes: calculating a difference between the silicon concentration of the processing liquid in the processing tank at a predetermined time after the start of etching processing of the substrate and the pre-processing concentration; estimating an amount of change in the silicon concentration of the processing liquid when the substrate is etched for the predetermined time based on further correlation data indicating a correlation between a processing time of the sample substrate and an amount of change in the silicon concentration of the processing liquid after etching processing of the sample substrate and the predetermined time; and correcting the processing time so that the difference between the calculated difference and the estimated amount of change is within a predetermined range.

5. The apparatus of claim 1 or 2, further comprising a discharge unit configured to discharge the processing liquid in the processing tank to the outside of the processing tank, and a supply unit configured to supply the processing liquid to the processing tank, wherein the control unit is configured to further execute a process of determining whether the pre-processing concentration is equal to or greater than a predetermined value before estimating the post-processing concentration, and a process of controlling the discharge unit and the supply unit so that the silicon concentration of the processing liquid becomes less than the predetermined value when it is determined that the pre-processing concentration is equal to or greater than the predetermined value.

6. The apparatus described in claim 1 or 2, further comprising: another measuring unit; a discharge unit configured to discharge the processing liquid in the processing tank to the outside of the processing tank; and a supply unit, wherein the processing liquid is a mixture of ultrapure water and at least one chemical liquid, the another measuring unit configured to measure a concentration of the mixture, the supply unit configured to supply at least one of the ultrapure water and the chemical liquid to the processing tank, and the control unit configured to further execute a process of controlling the discharge unit and the supply unit based on the concentration of the mixture so that the concentration of the mixture is within a predetermined range.

7. The apparatus of claim 1 or 2, wherein the measurement unit is configured to measure the silicon concentration of the processing liquid continuously over time.

8. The apparatus according to claim 1 or 2, wherein the processing liquid is an SC-1 liquid, which is a mixture containing ammonium hydroxide, hydrogen peroxide, and ultrapure water, an NC-2 liquid, which is a mixture containing choline, hydrogen peroxide, and ultrapure water, or a TMAH liquid, which is a mixture containing tetramethylammonium hydroxide and ultrapure water.

9. The apparatus according to claim 1 or 2, wherein the temperature of the treatment liquid is 40°C or higher and 80°C or lower.

10. A substrate processing method for etching a substrate containing polysilicon with an alkaline processing liquid stored in a processing tank, comprising: a first step of estimating a post-processing concentration, which is the silicon concentration of the processing liquid in the processing tank after the etching processing of the substrate, based on a value relating to the amount of polysilicon contained in the substrate and a pre-processing concentration, which is the silicon concentration of the processing liquid in the processing tank before the etching processing of the substrate, measured by a measuring unit configured to measure the silicon concentration of the processing liquid; and a second step of determining a processing time for the substrate in the processing tank based on correlation data indicating a correlation between the silicon concentration of the processing liquid in the processing tank after a sample substrate has been etched in the processing tank with the processing liquid and an etching rate of the sample substrate by the etching processing, and the post-processing concentration estimated in the first step.

11. The method according to claim 10, wherein the first step further comprises: a third step of estimating an amount of change in the silicon concentration of the processing liquid in the processing tank after the etching processing of the substrate based on a value relating to the amount of polysilicon contained in the sample substrate and another correlation data showing a correlation between the amount of polysilicon contained in the sample substrate and the amount of change in the silicon concentration of the processing liquid after the etching processing of the sample substrate, and the value relating to the amount of polysilicon in the substrate; and a fourth step of estimating the sum of the amount of change estimated in the third step and the pre-processing concentration as the post-processing concentration.

12. The method according to claim 10 or 11, wherein the substrate includes a plurality of layers, each of the plurality of layers includes the polysilicon, and the value relating to the amount of polysilicon includes the number of the substrates simultaneously processed in the processing tank and the number of the plurality of layers stacked on the substrate.

13. The method according to claim 10 or 11, further comprising: a fifth step of calculating a difference between the silicon concentration of the processing liquid in the processing tank at a predetermined time after the start of etching processing of the substrate and the concentration before processing; a sixth step of estimating an amount of change in the silicon concentration of the processing liquid when the substrate is etched for the predetermined time based on further correlation data indicating a correlation between a processing time of the sample substrate and an amount of change in the silicon concentration of the processing liquid after the etching processing of the sample substrate, and the predetermined time; and a seventh step of correcting the processing time so that the difference between the amount of difference calculated in the fifth step and the amount of change estimated in the sixth step falls within a predetermined range.

14. The method according to claim 10 or 11, further comprising: an eighth step of determining, before the first step, whether or not the pre-treatment concentration is equal to or greater than a predetermined value; and a ninth step of controlling, if it is determined in the eighth step that the pre-treatment concentration is equal to or greater than the predetermined value, a discharge unit configured to discharge the treatment liquid in the treatment tank to the outside of the treatment tank and a supply unit configured to supply the treatment liquid to the treatment tank so that the silicon concentration of the treatment liquid becomes less than the predetermined value.

15. The method according to claim 10 or 11, further comprising: a tenth step of measuring a concentration of the treatment liquid, which is a mixture of ultrapure water and at least one chemical liquid; and an eleventh step of controlling a discharge unit configured to discharge the treatment liquid in the treatment tank to the outside of the treatment tank and a supply unit configured to supply the treatment liquid to the treatment tank, based on the concentration of the mixture measured in the tenth step, so that the concentration of the mixture is within a predetermined range.

16. The method of claim 10 or 11, wherein the measurement unit is configured to measure the silicon concentration of the processing liquid continuously over time.

17. The method according to claim 10 or 11, wherein the treatment liquid is an SC-1 liquid, which is a mixture containing ammonium hydroxide, hydrogen peroxide, and ultrapure water, an NC-2 liquid, which is a mixture containing choline, hydrogen peroxide, and ultrapure water, or a TMAH liquid, which is a mixture containing tetramethylammonium hydroxide and ultrapure water.

18. The method according to claim 10 or 11, wherein the temperature of the treatment liquid is 40°C or higher and 80°C or lower.

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