Substrate processing method and substrate processing apparatus

Abstract

The present disclosure relates to a substrate processing method and a substrate processing apparatus, which improve uniformity in etching processing of a polysilicon film formed on a substrate. A substrate processing method according to one embodiment of the present disclosure comprises the steps of: adding a silicic acid compound to an alkaline processing liquid to generate an etching liquid; and etching the polycrystalline silicon film formed on the substrate by using an etching solution.

Description

Technical Field

[0001] The disclosed embodiments relate to a substrate processing method and a substrate processing apparatus. Background Technology

[0002] Previously, it was known that a technique was used to etch polycrystalline silicon films formed on a substrate using an alkaline processing solution (see Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2022-41076 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] This disclosure provides a technique that can improve the uniformity of etching processes for polycrystalline silicon films formed on substrates.

[0008] Solution for solving the problem

[0009] One aspect of the substrate processing method disclosed herein includes the following steps: adding a silica compound to an alkaline processing solution to generate an etching solution; and using the etching solution to etch a polycrystalline silicon film formed on the substrate.

[0010] The effects of the invention

[0011] According to this disclosure, the uniformity of etching processes for polycrystalline silicon films formed on substrates can be improved. Furthermore, the effects described herein are not necessarily limiting, and may be any effects intended to be described in this disclosure. Attached Figure Description

[0012] Figure 1 This is a schematic block diagram illustrating the structure of the substrate processing system according to the embodiment.

[0013] Figure 2 This is an enlarged cross-sectional view showing an example of the surface structure of the wafer involved in the embodiment.

[0014] Figure 3 This is a schematic block diagram showing the structure of the etching processing apparatus involved in the embodiment.

[0015] Figure 4 This is a flowchart illustrating an example of the control processing performed by the substrate processing system according to the embodiment.

[0016] Figure 5 This is a diagram illustrating an example of the shift in the concentration of silica compounds in the processing tank during the etching process involved in the embodiment.

[0017] Figure 6 This is a graph showing the relationship between the concentration of silica compounds added to the etching solution and the BT ratio.

[0018] Figure 7 This is another example of the shift in the concentration of silica compounds in the processing tank during the etching process involved in the embodiment.

[0019] Figure 8 This is another example of the shift in the concentration of silica compounds in the processing tank during the etching process involved in the embodiment.

[0020] Figure 9 This is another example of the shift in the concentration of silica compounds in the processing tank during the etching process involved in the embodiment.

[0021] Figure 10 This is another example of the shift in the concentration of silica compounds in the processing tank during the etching process involved in the embodiment.

[0022] Figure 11 This is a flowchart illustrating another example of the control processing performed by the substrate processing system according to the embodiment. Detailed Implementation

[0023] The embodiments of the substrate processing method and substrate processing apparatus disclosed in this application will now be described in detail with reference to the accompanying drawings. However, this disclosure is not limited by the embodiments shown below. It should also be noted that the drawings are schematic, and the relationships between the dimensions of the elements, the ratios of the elements, etc., may sometimes differ from reality. Furthermore, the drawings may sometimes include portions where the relationships between dimensions and ratios differ from each other.

[0024] Previously, techniques were known for etching polysilicon films formed on substrates using alkaline processing solutions. However, in the aforementioned prior art, there is sometimes a large difference between the amount of polysilicon film etched at the opening side of the hole and the amount of polysilicon film etched at the bottom side of the hole.

[0025] Therefore, it is desirable to realize a technology that can overcome the above-mentioned problems and improve the uniformity of the etching process of polycrystalline silicon films formed on substrates, such as the uniformity of the etching amount in the depth direction of holes formed on substrates.

[0026] <Structure of the substrate processing system>

[0027] First, refer to Figure 1 and Figure 2 The structure of the substrate processing system 1 involved in the embodiment will be explained. Figure 1This is a schematic block diagram showing the structure of the substrate processing system 1 according to the embodiment. The substrate processing system 1 is an example of a substrate processing apparatus.

[0028] like Figure 1 As shown, the substrate processing system 1 according to the embodiment includes a carrier loading and unloading section 2, a batch forming section 3, a batch placing section 4, a batch conveying section 5, a batch processing section 6, and a control device 7.

[0029] The load-bearing loading and unloading section 2 includes a load-bearing platform 20, a load-bearing conveying mechanism 21, load-bearing storage areas (stock) 22 and 23, and a load-bearing placement platform 24.

[0030] The carrier platform 20 holds multiple carriers C transported from the outside. The carrier C is a container that houses multiple (e.g., 25) wafers W arranged vertically in a horizontal orientation. The carrier transport mechanism 21 transports the carriers C between the carrier platform 20, the carrier storage areas 22 and 23, and the carrier placement stage 24.

[0031] Here, refer to Figure 2 The structure of the wafer W that is etched in the substrate processing system 1 according to the embodiment will be explained. Figure 2 This is an enlarged cross-sectional view showing an example of the surface structure of the wafer W according to the embodiment. The wafer W is an example of a substrate.

[0032] like Figure 2 As shown, in the substrate processing system 1 involved in the embodiment (refer to...) Figure 1 The wafer W, which is being etched in the process, has a substrate S, a silicon oxide film L1, a polysilicon film L2, and a silicon nitride film L3.

[0033] In the wafer W described in the embodiment, a silicon oxide film L1 is present on the surface of the wafer W, which is made of silicon or the like. Additionally, a polycrystalline silicon film L2 is present on the surface of the silicon oxide film L1.

[0034] Furthermore, on the surface of the polycrystalline silicon film L2, multiple silicon oxide films L1 and multiple silicon nitride films L3 are alternately arranged in a multilayer configuration. Moreover, a hole H is provided in the stack of silicon oxide film L1, polycrystalline silicon film L2, and silicon nitride film L3 described so far. The hole H is an example of a recess.

[0035] On the inner surface of the hole H, a silicon oxide film L1, a silicon nitride film L3, a silicon oxide film L1, and a polycrystalline silicon film L2 are sequentially stacked. That is, when the wafer W is processed in the substrate processing system 1, the polycrystalline silicon film L2 is exposed on the inner surface of the hole H.

[0036] Furthermore, in the etching process involved in the embodiment, a portion of the polysilicon film L2 located on the inner surface of the hole H is etched.

[0037] return Figure 1 The substrate transfer mechanism 30, described later, moves multiple wafers W from the carrier C placed on the carrier stage 24 to the batch processing unit 6 before processing. Additionally, the substrate transfer mechanism 30 moves multiple processed wafers W from the batch processing unit 6 into the carrier C placed on the carrier stage 24.

[0038] The batch forming unit 3 has a substrate conveying mechanism 30 for forming batches. A batch consists of multiple (e.g., 50 wafers) of wafers W to be processed simultaneously by combining wafers W housed in one or more carriers C.

[0039] Multiple wafers W forming a batch are arranged at fixed intervals with their face-to-face orientation. Furthermore, this disclosure is not limited to a batch consisting of multiple wafers W; a batch may also consist of a single wafer W.

[0040] The substrate transfer mechanism 30 transfers multiple wafers W between the carrier C placed on the carrier stage 24 and the batch placement section 4.

[0041] The batch placement unit 4 has a batch transport stage 40, which temporarily holds (standby) batches that are transported between the batch forming unit 3 and the batch processing unit 6 by the batch transport unit 5. The batch transport stage 40 has a placement stage 41 for placing the batches formed by the batch forming unit 3 before processing and a placement stage 42 for placing the batches processed by the batch processing unit 6. On the placement stages 41 and 42, multiple wafers W of a batch are placed in a vertical arrangement, one after the other.

[0042] The batch transfer unit 5 has a batch transfer mechanism 50, which performs batch transfer between the batch placement unit 4 and the batch processing unit 6, and inside the batch processing unit 6. The batch transfer mechanism 50 has a guide rail 51, a moving body 52, and a substrate holder 53.

[0043] The guide rail 51 is arranged along the X-axis, spanning the batch placement section 4 and the batch processing section 6. The moving body 52 is configured to move along the guide rail 51 while holding multiple wafers W. The substrate holder 53 is located on the moving body 52 and holds the multiple wafers W arranged back-to-back in an upright position.

[0044] The batch processing unit 6 performs etching, cleaning, and drying processes on multiple wafers W in a single batch. In the batch processing unit 6, two etching units 60, a cleaning unit 70, a cleaning unit 80, and a drying unit 90 are arranged along the guide rail 51.

[0045] Etching apparatus 60 etches multiple wafers W in a batch simultaneously. Cleaning apparatus 70 cleans multiple wafers W in a batch simultaneously. Cleaning apparatus 80 cleans the substrate holder 53. Drying apparatus 90 dries multiple wafers W in a batch simultaneously. Furthermore, the number of etching apparatus 60, cleaning apparatus 70, cleaning apparatus 80, and drying apparatus 90 is not limited to... Figure 1 Examples.

[0046] The etching processing apparatus 60 includes an etching processing tank 61, a rinsing processing tank 62, and substrate lifting mechanisms 63 and 64.

[0047] The processing tank 61 is capable of accommodating a batch of wafers W arranged in an upright position and storing the etching solution (hereinafter also referred to as "etching solution"). Details about the processing tank 61 are described later.

[0048] The rinsing solution (such as deionized water) is stored in the processing tank 62. The substrate lifting mechanisms 63 and 64 hold multiple wafers W in batches in an upright position, arranged back and forth.

[0049] The etching processing apparatus 60 holds the batch transported by the batch transfer unit 5 via the substrate lifting mechanism 63 and immerses it in the etching solution L in the processing tank 61 (see reference). Figure 2 (To perform etching)

[0050] After being etched in processing tank 61, the batch is transferred to processing tank 62 by batch transfer unit 5. Then, etching processing apparatus 60 holds the transferred batch by substrate lifting mechanism 64 and performs rinsing by immersing it in rinsing liquid in processing tank 62. After being rinsed in processing tank 62, the batch is transferred to processing tank 71 of cleaning processing apparatus 70 by batch transfer unit 5.

[0051] The cleaning processing apparatus 70 includes a cleaning tank 71, a rinsing tank 72, and substrate lifting mechanisms 73 and 74. The cleaning solution is stored in the cleaning tank 71.

[0052] The rinsing solution (deionized water, etc.) is stored in the rinsing tank 72. The substrate lifting mechanisms 73 and 74 hold multiple wafers W in a batch in an upright position, arranged back and forth.

[0053] The cleaning process apparatus 70 holds the batches transported by the batch transfer unit 5 via the substrate lifting mechanism 73, and performs cleaning by immersing them in the cleaning solution of the processing tank 71. After being cleaned in the processing tank 71, the batches are transferred by the batch transfer unit 5 to the processing tank 72.

[0054] The cleaning process apparatus 70 holds the batch transported from the processing tank 71 by the substrate lifting mechanism 74 and performs rinsing by immersing it in the rinsing liquid of the processing tank 72. After being rinsed in the processing tank 72, the batch is transported by the batch transfer unit 5 to the processing tank 91 of the drying process apparatus 90.

[0055] The drying apparatus 90 includes a processing tank 91 and a substrate lifting mechanism 92. A drying gas is supplied to the processing tank 91. In the substrate lifting mechanism 92, multiple wafers W in a batch are held in an upright, back-to-back arrangement.

[0056] The drying apparatus 90 holds the batches transported by the batch transfer unit 5 via the substrate lifting mechanism 92, and performs drying treatment using processing gas supplied to the processing tank 91. After being dried in the processing tank 91, the batches are transferred by the batch transfer unit 5 to the batch placement unit 4.

[0057] The cleaning process apparatus 80 performs cleaning process on the substrate holder 53 by supplying a cleaning solution and a drying gas to the substrate holder 53 of the batch conveying mechanism 50.

[0058] In addition, the substrate processing system 1 includes a control device 7. The control device 7 is, for example, a computer, and includes a control unit 9 and a storage unit 10. The storage unit 10 stores programs for controlling various processes performed in the substrate processing system 1. The control unit 9 controls the operation of the substrate processing system 1 by reading and executing the programs stored in the storage unit 10.

[0059] Furthermore, the program can also be recorded on a computer-readable storage medium and installed from that storage medium into the storage unit 10 of the control device 7. Examples of computer-readable storage media include hard disks (HD), floppy disks (FD), optical disks (CD), magneto-optical disks (MO), and memory cards.

[0060] <Structure of the Etching Processing Equipment>

[0061] Next, refer to Figure 3 The structure of the etching process apparatus 60 for performing the etching process of wafer W will be explained. Figure 3 This is a schematic block diagram showing the structure of the etching processing apparatus 60 according to the embodiment.

[0062] The etching apparatus 60 includes a processing liquid supply unit 100, a silica supply unit 110, and a substrate processing unit 120. The processing liquid supply unit 100 supplies an alkaline processing liquid, which is a raw material for the etching liquid L, to the substrate processing unit 120.

[0063] Furthermore, in the following embodiments, an example of an alkaline treatment solution, namely SC1, is shown as a mixture of ammonia water and hydrogen peroxide water, but the alkaline treatment solution in this disclosure is not limited to SC1.

[0064] The processing liquid supply unit 100 includes an ammonia supply unit 101, a hydrogen peroxide supply unit 102, an HDIW supply unit 103, and a CDIW supply unit 104.

[0065] The ammonia supply unit 101 includes an ammonia supply source 101a, an ammonia supply path 101b, and a flow regulator 101c.

[0066] The ammonia supply source 101a is, for example, a tank for storing ammonia (ammonia solution, NH4OH). The ammonia supply line 101b connects the ammonia supply source 101a to the outer tank 122 of the treatment tank 61, and supplies ammonia from the ammonia supply source 101a to the outer tank 122.

[0067] The flow regulator 101c is located in the ammonia supply line 101b and adjusts the flow rate of ammonia supplied to the external tank 122. The flow regulator 101c includes an on / off valve, a flow control valve, and a flow meter.

[0068] The hydrogen peroxide water supply unit 102 includes a hydrogen peroxide water supply source 102a, a hydrogen peroxide water supply path 102b, and a flow regulator 102c.

[0069] Hydrogen peroxide water supply source 102a is, for example, a tank for storing hydrogen peroxide water (hydrogen peroxide aqueous solution, H2O2). Hydrogen peroxide water supply path 102b connects hydrogen peroxide water supply source 102a to outer tank 122, supplying hydrogen peroxide water from hydrogen peroxide water supply source 102a to outer tank 122.

[0070] The flow regulator 102c is located in the hydrogen peroxide water supply line 102b and adjusts the flow rate of hydrogen peroxide water supplied to the external tank 122. The flow regulator 102c includes an on / off valve, a flow control valve, and a flow meter.

[0071] The HDIW supply unit 103 supplies high-temperature DIW (Deionized Water) to the outer tank 122 to adjust the concentration and temperature of the etching solution L stored in the processing tank 61. The HDIW supply unit 103 includes an HDIW supply source 103a, an HDIW supply path 103b, and a flow regulator 103c.

[0072] HDIW supply source 103a is, for example, a tank for storing high-temperature DIW. HDIW supply path 103b connects HDIW supply source 103a to outer tank 122, supplying high-temperature DIW from HDIW supply source 103a to outer tank 122.

[0073] The flow regulator 103c is located in the HDIW supply line 103b and adjusts the supply of high-temperature DIW to the outer tank 122. The flow regulator 103c includes an on / off valve, a flow control valve, and a flow meter.

[0074] The temperature of the etching solution L, the concentration of SC1, and the concentration of the silica compound in the etching processing apparatus 60 are adjusted by regulating the supply of the high-temperature DIW by the flow regulator 103c.

[0075] The CDIW supply unit 104 supplies room temperature DIW to the inner tank 121 of the processing tank 61 to adjust the concentration and temperature of the etching solution L stored in the processing tank 61. The CDIW supply unit 104 includes a CDIW supply source 104a, a CDIW supply path 104b, and a flow regulator 104c.

[0076] CDIW supply source 104a is, for example, a tank for storing room temperature DIW. CDIW supply path 104b connects CDIW supply source 104a to inner tank 121, supplying room temperature DIW from CDIW supply source 104a to inner tank 121.

[0077] The flow regulator 104c is located in the CDIW supply line 104b and adjusts the supply amount of room temperature DIW to the inner tank 121. The flow regulator 104c includes an on / off valve, a flow control valve, and a flow meter.

[0078] The temperature of the etching solution L, the concentration of SC1, and the concentration of the silica compound in the etching processing apparatus 60 are adjusted by regulating the supply of DIW at room temperature using the flow regulator 104c.

[0079] The silica supply unit 110 supplies silica compound, which is a raw material for etching solution L, to the substrate processing unit 120. The silica supply unit 110 includes a silica supply source 110a, a silica supply path 110b, and a supply quantity adjuster 110c.

[0080] The silica supply source 110a is, for example, a tank for storing silica compounds. The silica compounds stored in the silica supply source 110a comprise at least one of silicate and silicate.

[0081] The silicate contained in the silicic acid compound involved in the embodiments is, for example, colloidal silica. The silicate contained in the silicic acid compound involved in the embodiments is, for example, at least one of sodium silicate, potassium silicate, and calcium silicate.

[0082] The silica supply line 110b connects the silica supply source 110a to the confluence section 101d located in the ammonia supply line 101b, and supplies silica compound from the silica supply source 110a to the ammonia supply line 101b.

[0083] The supply regulator 110c is located in the silica supply line 110b and adjusts the amount of silica compound supplied to the ammonia supply line 101b.

[0084] In this embodiment, a silica compound is supplied to the ammonia supply line 101b, so that the silica compound is dissolved in the ammonia while being supplied to the substrate processing section 120. This helps to suppress the accumulation of silica particles in the piping.

[0085] Furthermore, this disclosure is not limited to the case where the silica compound is supplied from the silica supply source 110a to the processing tank 61 via the ammonia supply line 101b. For example, in this disclosure, the silica compound may also be supplied from the silica supply source 110a to the processing tank 61 via the HDIW supply line 103b. In this case, the silica compound is supplied to the processing tank 61 while dissolving in the high-temperature DIW. This also helps to suppress the presence of residual silica particles in the piping.

[0086] Alternatively, in this disclosure, the silica compound can be directly supplied from the silica supply source 110a to the outer tank 122. This allows for precise adjustment of the concentration of the silica compound within the processing tank 61.

[0087] The substrate processing unit 120 immerses multiple wafers W (i.e., batches) in an etching solution L generated by adding a silica compound to an alkaline processing solution to perform etching processing on the multiple wafers W.

[0088] The substrate processing unit 120 includes a processing tank 61, a substrate lifting mechanism 63, a circulation path 130, and an etching solution discharge unit 140. The processing tank 61 includes an inner tank 121, an outer tank 122, and a liquid level sensor 123.

[0089] The inner tank 121 is a tank used to immerse multiple wafers W in an etching solution L, and contains the etching solution L for immersion. The inner tank 121 has an opening 121a at the top, and the etching solution L is stored up to the vicinity of the opening 121a.

[0090] In the inner tank 121, a substrate lifting mechanism 63 is used to immerse multiple wafers W in the etching solution L and perform etching on the multiple wafers W. The substrate lifting mechanism 63 is configured to be able to lift and hold the multiple wafers W in a vertical, front-to-back arrangement.

[0091] The outer tank 122 is disposed outside the inner tank 121 in a manner that surrounds the inner tank 121, and receives the etching solution L flowing out from the opening 121a of the inner tank 121. Figure 3As shown, the liquid level in the outer tank 122 is maintained at a level lower than that in the inner tank 121.

[0092] The liquid level sensor 123 measures the height of the etching solution L stored in the outer tank 122. The control unit 9 involved in the embodiment (see...) Figure 1 The volume of etching solution L stored in the processing tank 61 can be determined based on the height of the outer tank 122 measured by the liquid level sensor 123.

[0093] This is because the inner tank 121 and the circulation path 130 are filled with etching solution L, so the liquid volume is always fixed. Therefore, by measuring the liquid volume inside the outer tank 122 based on the liquid level sensor 123, the overall liquid volume of the processing tank 61 can be determined.

[0094] The outer tank 122 and the inner tank 121 are connected by a circulation path 130. One end of the circulation path 130 is connected to the bottom of the outer tank 122, and the other end of the circulation path 130 is connected to the ejection nozzle 124 located in the inner tank 121.

[0095] In the circulation path 130, starting from the outer tank 122 side, a pump 131, a heater 132, a filter 133, and a branch section 134 are arranged in sequence.

[0096] Pump 131 is used to create a circulating flow of etching solution L from outer tank 122 to inner tank 121 via circulation path 130. In addition, etching solution L overflows from opening 121a of inner tank 121 and flows out of outer tank 122 again.

[0097] In this way, a circulating flow of etching solution L is formed within the substrate processing section 120. That is, this circulating flow is formed in the outer tank 122, the circulation path 130, and the inner tank 121.

[0098] Heater 132 adjusts the temperature of the etching solution L circulating in circulation path 130. Filter 133 filters the etching solution L circulating in circulation path 130.

[0099] Branch path 135 branches out from branch section 134. Branch path 135 connects branch section 134 to outer tank 122. Concentration measuring unit 136 is provided in branch path 135. Concentration measuring unit 136 measures the concentration of the components of the etching solution L stored in processing tank 61 and flowing in branch path 135.

[0100] The concentration measuring unit 136 includes, for example, a concentration sensor 137 and a concentration sensor 138. The concentration sensor 137, for example, measures the concentration of silica compounds in the composition of the etching solution L.

[0101] Concentration sensor 138, for example, measures the concentration of alkaline treatment solution in the composition of etching solution L. The signal generated by concentration measuring unit 136 is sent to control device 7 (see reference). Figure 1 ).

[0102] When replacing all or part of the etching solution L used in the etching process, the etching solution discharge unit 140 discharges the etching solution L to the discharge port DR. The etching solution discharge unit 140 includes a discharge path 140a, a flow regulator 140b, and a cooling tank 140c.

[0103] Discharge path 140a is connected to circulation path 130. Flow regulator 140b is located in discharge path 140a and adjusts the discharge rate of etching solution L. Flow regulator 140b includes an on / off valve, a flow control valve, and a flow meter.

[0104] Cooling tank 140c temporarily stores and cools the etching solution L flowing from discharge path 140a. In cooling tank 140c, the discharge rate of etching solution L is adjusted by flow regulator 140b.

[0105] <Implementation Method>

[0106] Next, refer to Figures 4-11 To explain the details of the etching process involved in the implementation method. Figure 4 This is a flowchart illustrating an example of the control processing performed by the substrate processing system 1 according to the embodiment.

[0107] In the control process involved in the embodiment, firstly, the control unit 9 controls the etching solution discharge unit 140, etc., to discharge the used etching solution L stored in the processing tank 61 from the processing tank 61 (step S101).

[0108] Next, the control unit 9 controls the processing liquid supply unit 100, etc., to supply the processing tank 61 with SC1, which is an alkaline processing liquid (step S102). In the process of this step S102, for example, the control unit 9 supplies ammonia water, hydrogen peroxide water and high temperature DIW to the processing tank 61 so that the concentration of ammonia water and hydrogen peroxide water in the processing tank 61 is a given concentration.

[0109] Next, the control unit 9 controls the silica supply unit 110, etc., to add silica compound to SC1 in the processing tank 61 (step S103). Thus, as... Figure 5 As shown, starting from the processing time T02 of the initial step S103, the concentration of silica compounds in the processing tank 61 increases. Figure 5 This is a diagram illustrating an example of the shift in the concentration of silica compounds within the processing tank 61 during the etching process involved in the embodiment.

[0110] In addition, Figure 5 During this process, from time T01 to time T02, the processing liquid supply process described in step S102 is performed. Additionally, in... Figure 5In the example, at time T01, the concentration of the silica compound is almost zero, and this concentration is maintained until time T02.

[0111] return Figure 4 The explanation continues. Next, the control unit 9 determines whether the concentration of the silica compound in the processing tank 61 has reached a given concentration (e.g., Figure 5 The concentration recorded is C1 (step S104).

[0112] Then, when the concentration of the silica compound in the processing tank 61 reaches a given concentration (step S104: "Yes"), the control unit 9 considers that the etching solution L involved in the embodiment has been generated, and moves a batch consisting of multiple wafers W into the processing tank 61 (step S105).

[0113] For example, such as Figure 5 As shown, at time T03, when the concentration of the silica compound in the processing tank 61 reaches a given concentration C1, the control unit 9 ends the silica compound addition process. Thus, the concentration of the silica compound in the processing tank 61 is maintained at the given concentration C1.

[0114] On the other hand, if the concentration of silica compound in the processing tank 61 does not reach the given concentration (step S104: "No"), the process returns to step S103.

[0115] Next, in step S105, the control unit 9 immerses the batch that has been moved into the processing tank 61 in the etching solution L and performs etching on the multiple wafers W included in the batch (step S106).

[0116] As explained above, in this embodiment, the polysilicon film L2 located on the surface of the wafer W is etched using an etch solution L, which is prepared by adding a silica compound to an alkaline processing solution (e.g., SC1).

[0117] Therefore, the uniformity of the etching process of the polycrystalline silicon film L2 can be improved, for example... Figure 2 The uniformity between the etching amount of the polysilicon film L2 at the bottom of hole H and the etching amount of the polysilicon film L2 at the opening of hole H is improved. The reason for this is explained below.

[0118] In the etching process of the polycrystalline silicon film L2 using alkaline SC1, hydrogen peroxide water reacts inside SC1 as shown in the following chemical formulas (1) and (2), thereby generating oxygen molecules O2 and hydroxide ions OH. - .

[0119]

[0120] In addition, during the etching process using SC1, ammonia reacts inside SC1 as shown in the following chemical formula (3), thereby generating hydroxide ions OH. - .

[0121]

[0122] Furthermore, the oxygen molecules O2 generated by the above chemical formula (2) react with the polycrystalline silicon film L2, thereby generating silicon oxide SiO2 as shown in the following chemical formula (4).

[0123] Furthermore, the hydroxide ions (OH) generated by the above chemical formulas (1) and (3) - The silicon oxide SiO2 generated by the above chemical formula (4) and the polycrystalline silicon film L2 react to generate silicic acid Si(OH)4 as shown in the following chemical formulas (5) and (6).

[0124] In this way, the reactions of the above chemical formulas (1) to (6) continue to occur in the etching solution L, thereby gradually increasing the concentration of silica in the etching solution L. As a result, the reactions of the above chemical formulas (5) and (6) are difficult to proceed to the right as the etching process progresses.

[0125] In this case, when etching the polycrystalline silicon film L2 using an alkaline treatment solution, a higher concentration of silicic acid results in a lower etching rate. Furthermore, an example using SC1 as the alkaline treatment solution is shown here, but the same chemical reaction occurs even with alkaline treatment solutions other than SC1.

[0126] Furthermore, when the polysilicon film L2 located on the inner surface of the hole H is etched using an alkaline treatment solution as in the prior art, it is easier to supply new treatment solution at the opening of the hole H, so the aforementioned reduction in etching rate is less likely to occur.

[0127] On the other hand, at the bottom of hole H, it is difficult to supply new processing liquid compared to the opening, so the concentration of silica is more likely to increase compared to the opening, thus the aforementioned reduction in etching rate is more likely to occur.

[0128] Therefore, in the prior art, the ratio of the etching rate at the bottom of the hole H to the etching rate at the opening of the hole H (also referred to in this disclosure as "BT (Bottom to Top) ratio") is reduced, resulting in poor uniformity of the etching process.

[0129] However, in this embodiment, a silica compound is added to the alkaline processing solution from the beginning of the etching process. As a result, the aforementioned reduction in etching rate is more likely to occur at the opening of the hole H from the beginning of the etching process.

[0130] Therefore, in this embodiment, compared with the prior art, a balance can be achieved between the frequency of etching reaction at the opening of the hole H and the frequency of etching reaction at the bottom of the hole H.

[0131] Therefore, according to the embodiment, the uniformity of the etching process of the polysilicon film L2, for example, the uniformity between the etching amount of the polysilicon film L2 located at the bottom of the hole H and the etching amount of the polysilicon film L2 located at the opening of the hole H, can be improved.

[0132] Figure 6 This is a graph showing the relationship between the concentration of the silica compound added to the etching solution L and the BT ratio. (See figure.) Figure 6 As shown, when the concentration of silica compound is 0 ppm, that is, when no silica compound is added to the alkaline treatment solution at the beginning of the etching process, the BT ratio is significantly lower than the ideal value of 1.0.

[0133] On the other hand, it can be seen that when etching is performed using an etching solution L containing 80 ppm or 160 ppm silica compound added from the beginning of the etching process, as in the embodiment, the BT ratio is close to the ideal value of 1.0, and the uniformity of the etching process is improved.

[0134] In this way, in one embodiment, by using an etch solution L, which is made by adding a silica compound to an alkaline processing solution, to etch the wafer W, the uniformity of the polysilicon film L2 during the etching process can be improved.

[0135] Furthermore, in this embodiment, in the process of adding a silica compound to an alkaline treatment solution to generate the etching solution L, the concentration of the silica compound can be 400 ppm or less. This further improves the uniformity of the etching process of the polycrystalline silicon film L2.

[0136] return Figure 4 Explanation. In parallel with the etching process in step S106, the control unit 9 controls the silica supply unit 110, etc., to add silica compound to the etching solution L in the processing tank 61 (step S107).

[0137] For example, in the implementation method, such as Figure 5 As shown, it is best to add the silica compound to the etching solution L by means of a standard curve connecting the given concentration C1 at the start time T04 of the etching process and the given concentration C2 at the end time T05 of the etching process.

[0138] In addition, relevant data, including data on the standard curve, and the correlation between the concentration of silica compound in the etching solution L in the processing tank 61 and the etching rate of the polysilicon film L2, are pre-stored in the storage unit 10.

[0139] Figure 7 and Figure 8 This is a diagram illustrating another example of the shift in the concentration of silica compounds within the processing tank 61 during the etching process involved in the embodiment. (See diagram for example.) Figure 7 As shown, when a batch consists of 1 wafer W, compared to a batch consisting of 50 wafers W, the amount of silica dissolved in the etching solution L during the etching process is less, and therefore the slope of the increase in silica compound concentration is smaller.

[0140] Therefore, in the case where a batch consists of 1 wafer W, compared to a batch consisting of 50 wafers W, especially in the latter half of the etching process, the etching rate can become very large.

[0141] Therefore, in the embodiment, the control unit 9 confirms the composition of the batch to be processed in advance. When the batch to be processed consists of a small number of wafers W, the amount of silica compound added in step S107 is increased compared to the case where the batch consists of a large number of wafers W.

[0142] Therefore, even when etching is performed on batches consisting of any number of sheets, etching can be carried out with the same concentration of silicate compound throughout the entire etching process. Thus, according to the embodiment, etching can be performed under identical conditions across multiple batches.

[0143] In addition, such as Figure 8 As shown, when there are 100 layers of multilayer film on the surface of wafer W, compared with the case where there are 400 layers of multilayer film on the surface of wafer W, the amount of silica dissolved in the etching solution L during the etching process is less, and therefore the slope of the increase in the concentration of silica compound is smaller.

[0144] Therefore, when there are 100 layers of multilayer film on the surface of wafer W, compared with the case where there are 400 layers of multilayer film on the surface of wafer W, the etching rate may become very large, especially in the latter half of the etching process.

[0145] Therefore, in the embodiment, the control unit 9 confirms the composition of the batch to be processed in advance. If the wafer W included in the batch to be processed is composed of fewer layers, the amount of silica compound added in step S107 is increased compared to the case where the wafer W is composed of more layers.

[0146] Therefore, even when etching a wafer W composed of any number of layers, the etching process can be carried out with the same concentration of silicate compound throughout the entire etching process. Thus, according to the embodiment, etching can be performed under identical conditions across multiple batches.

[0147] return Figure 4 The explanation continues. Following the processing of steps S106 and S107 above, the control unit 9 determines whether the given processing time has elapsed (step S108).

[0148] Then, after a given processing time has elapsed (step S108: "Yes"), the control unit 9 considers the etching process of the batch to be complete, removes the batch from the processing tank 61 (step S109), and ends a series of control processes.

[0149] On the other hand, if no given processing time has elapsed (step S108: "No"), return to the processing of steps S106 and S107.

[0150] In addition, the control unit 9 performs rinsing, cleaning and drying processes on the batches removed from the processing tank 61, and then moves the batches from the batch processing unit 6 to the carrier inlet and outlet unit 2.

[0151] In addition, Figure 5 In this process, starting from the end time T05 of one batch of etching treatment, as part of the etching treatment of the next batch, the aforementioned step S101, in which the used etching solution L stored in the treatment tank 61 is discharged from the treatment tank 61, is performed. Thus, as... Figure 5 As shown, the concentration of silica compounds in the treatment tank 61 is reduced.

[0152] Here, if the used etching solution L is not completely drained, sometimes silica compounds remain in the processing tank 61. Figure 5 The concentration of the silica compound at time T01 did not return to zero. In this case, the following can also be performed in the embodiment: Figure 9 or Figure 10 The processing is shown.

[0153] Figure 9 and Figure 10 This is another example illustrating the shift in the concentration of silicate compounds within the processing tank 61 during the etching process involved in the embodiment. Figure 9 In the example, when the concentration of silica compound in the processing tank 61 at time T01 is a concentration C3 greater than zero, the control unit 9 performs the above-mentioned steps S102 and S103 with the same supply and addition amount as when the concentration of silica compound in the processing tank 61 is zero.

[0154] Therefore, as Figure 9 As shown, at time T03, the concentration of silicate compound in the processing tank 61 becomes a concentration C4 that is greater than a given concentration C1. In this case, the control unit 9 discharges the etching solution L from the etching solution discharge unit 140 and replenishes SC1 from the processing solution supply unit 100, thereby reducing the concentration of silicate compound in the processing tank 61.

[0155] Therefore, the concentration of silica compound in the processing tank 61 can be made to a given concentration C1 at the time T04 when the etching process begins.

[0156] In addition, Figure 10 In the example, when the concentration of silica compound in the processing tank 61 at time T01 is a concentration C3 greater than zero, the control unit 9 performs the above-mentioned step S102 processing with the same supply amount as when the concentration of silica compound in the processing tank 61 is zero.

[0157] Furthermore, during the processing in step S103, the control unit 9 adds less silica compound than if the concentration of silica compound in the processing tank 61 were zero. This allows the concentration of silica compound in the processing tank 61 to reach a given concentration C1 at the time T03, the end of processing in step S103.

[0158] In addition, in this embodiment, the alkaline treatment solution used as the raw material for the etching solution L can also be diluted ammonia, SC1, NC2 (a mixture of choline aqueous solution and hydrogen peroxide solution), or TMAH (tetramethylammonium hydroxide). This allows for efficient etching of the polycrystalline silicon film L2 formed on the surface of the wafer W.

[0159] Furthermore, in this embodiment, the silica compound used as a raw material for the etching solution L may also include at least one of silicic acid and silicate. Therefore, the silica compound can be easily dissolved in an alkaline processing solution, thus allowing for the simple generation of the etching solution L.

[0160] Furthermore, in the embodiment, the control unit 9 may also adjust the etching time of the batch based on the concentration of silica compound in the processing tank 61. For example, if the concentration of silica compound in the processing tank 61 gradually increases to a slightly higher concentration than the desired concentration, the control unit 9 preferably makes the etching time longer than the desired time.

[0161] In addition, if the concentration of silica compound in the processing tank 61 is slightly lower than the desired concentration, the control unit 9 preferably makes the etching process time shorter than the desired time.

[0162] By adjusting the etching time according to the concentration of silica compound in the processing tank 61, etching can be performed under the same conditions across multiple batches.

[0163] Furthermore, in this embodiment, the temperature of the etchant L during batch etching can be 40°C to 80°C. This allows for efficient etching of the polysilicon film L2 formed on the surface of the wafer W.

[0164] Furthermore, in this embodiment, the concentration sensor 137 for measuring the concentration of silica compounds in the etching solution L can be a microwave plasma atomic emission spectrometer, a high-frequency inductively coupled plasma atomic emission spectrometer, or an inductively coupled high-frequency plasma mass spectrometer. This allows for the high-precision measurement of the concentration of silica compounds in the etching solution L.

[0165] In addition, in the embodiment, the control unit 9 may replace the etching solution L in the processing tank 61 before the etching process of the next batch if it is determined that the concentration of silica compound in the processing tank 61 will reach a given threshold after the etching process of the next batch.

[0166] Therefore, when etching the next batch of samples, the excessive increase in the concentration of silica compounds in the processing tank 61 can be suppressed, thus enabling the desired etching process to be carried out stably.

[0167] In addition, in this embodiment, the control unit 9 may also control the operation of the processing liquid supply unit 100 to keep the concentration of the alkaline processing liquid in the processing tank 61 within a given concentration range. For example, if the concentration of the processing liquid in the processing tank 61 is higher than the given concentration range, the control unit 9 preferably discharges the etching liquid L from the etching liquid discharge unit 140 and replenishes the processing liquid with a low concentration of processing liquid or HDIW from the processing liquid supply unit 100.

[0168] In addition, if the concentration of the processing liquid in the processing tank 61 is lower than a given concentration range, the control unit 9 preferably discharges the etching liquid L from the etching liquid discharge unit 140 and replenishes the processing liquid with a high concentration from the processing liquid supply unit 100.

[0169] By stabilizing the concentration of the alkaline treatment solution in the treatment tank 61 within a given concentration range in this way, the desired etching process can be carried out stably.

[0170] Figure 11 This is a flowchart illustrating another example of the control processing performed by the substrate processing system 1 according to the embodiment.

[0171] exist Figure 11In the control process involved in the example, firstly, the control unit 9 controls the etching solution discharge unit 140, etc., to discharge the used etching solution L stored in the processing tank 61 from the processing tank 61 (step S201). Then, the control unit 9 controls the processing solution supply unit 100, etc., to supply the processing tank 61 with the alkaline processing solution SC1 (step S202).

[0172] Next, the control unit 9 controls the silica supply unit 110 and the like to add silica compound to SC1 in the processing tank 61 (step S203).

[0173] Next, the control unit 9 determines whether the concentration of the silica compound in the processing tank 61 has reached a given concentration (step S204). Then, if the concentration of the silica compound in the processing tank 61 has reached the given concentration (step S204: "Yes"), the control unit 9 transfers the batch into the processing tank 61 (step S205).

[0174] On the other hand, if the concentration of silica compound in the processing tank 61 does not reach the given concentration (step S204: "No"), the process returns to step S203.

[0175] Next, in step S205, the control unit 9 immerses the batch that has been moved into the processing tank 61 in the etching solution L, and performs etching on the multiple wafers W included in the batch (step S206). The processes described up to this point, S201 to S206, are the same as those described above, S101 to S106, so detailed descriptions are omitted.

[0176] In parallel with the etching process in step S206, the control unit 9 controls the silica supply unit 110 and the like to add silica compound to the etching solution L in the processing tank 61 (step S207).

[0177] Next, the control unit 9 determines whether the concentration of silica compound in the processing tank 61 has risen excessively (step S208). Then, if the concentration of silica compound in the processing tank 61 has risen excessively (step S208: "Yes"), the control unit 9 supplies alkaline processing liquid to the processing tank 61 to reduce the concentration of silica compound (step S209), and returns to the processing in step S207.

[0178] On the other hand, if the concentration of silica compound in the processing tank 61 does not rise excessively (step S208: "No"), the process proceeds to step S210.

[0179] Following steps S206 and S208, the control unit 9 determines whether the given processing time has elapsed (step S210). Then, if the given processing time has elapsed (step S210, "Yes"), the control unit 9 considers the etching process of the batch to be complete, removes the batch from the processing tank 61 (step S211), and ends the series of control processes.

[0180] On the other hand, if no given processing time has elapsed (step S210: "No"), return to the processing of steps S206 and S207.

[0181] As explained so far, in Figure 11 In the example, if the concentration of silica compound in the processing tank 61 reaches a given threshold during a certain batch of etching processes, at least a portion of the etching solution L in the processing tank 61 can be replaced during that batch of etching processes.

[0182] This allows the concentration of the alkaline treatment solution in the treatment tank 61 to be stabilized within a given concentration range, thus enabling the desired etching process to be carried out stably.

[0183] The substrate processing method according to the embodiment includes a step of generating an etchant L (steps S102 and S103) and a step of performing etching (step S106). In the step of generating the etchant L (steps S102 and S103), a silica compound is added to an alkaline processing solution to generate the etchant L. The etching step (step S106) includes etching a polysilicon film L2 formed on a substrate (wafer W) using the etchant L. This improves the uniformity of the etching process of the polysilicon film L2 formed on the wafer W.

[0184] Furthermore, in the substrate processing method described in the embodiment, the polysilicon film L2 is located on the inner surface of the recess (hole H) formed on the surface of the substrate (wafer W). Moreover, in the etching process (step S106), at least a portion of the polysilicon film L2 located on the inner surface of the recess (hole H) is etched. This improves the uniformity between the amount of etching of the polysilicon film L2 at the bottom of the hole H and the amount of etching of the polysilicon film L2 at the opening of the hole H.

[0185] Furthermore, in the substrate processing method described in the embodiments, the silica compound is colloidal silicon dioxide. This allows for the easy generation of the etching solution L.

[0186] Furthermore, in the substrate processing method described in the embodiments, the silicate compound is at least one of sodium silicate, potassium silicate, and calcium silicate. This allows for the easy generation of the etching solution L.

[0187] Furthermore, in the substrate processing method described in the embodiments, the processing solution is diluted ammonia, SC1, NC2, or TMAH. This allows for efficient etching of the polysilicon film L2 formed on the surface of the wafer W.

[0188] Furthermore, the substrate processing apparatus (substrate processing system 1) according to the embodiment includes a processing tank 61, a processing liquid supply unit 100, a silicate supply unit 110, a concentration measuring unit 136, a control unit 9, and a storage unit 10. The processing tank 61 is used to immerse a batch of substrates (wafers W) in an etching solution L generated by adding a silicate compound to an alkaline processing liquid for etching processing. The processing liquid supply unit 100 supplies processing liquid to the processing tank 61. The silicate supply unit 110 supplies silicate compound to the processing tank 61. The concentration measuring unit 136 measures the concentration of the components of the etching solution L stored in the processing tank 61. The control unit 9 controls each unit. The storage unit 10 stores relevant data, which stores the correlation between the concentration of the silicate compound in the etching solution L in the processing tank 61 and the etching rate of the polysilicon film L2 formed on the substrate (wafer W). This improves the uniformity of the etching process of the polysilicon film L2 formed on the wafer W.

[0189] Furthermore, in the substrate processing apparatus (substrate processing system 1) according to the embodiment, the control unit 9 adjusts the amount of silicate compound supplied to the processing tank 61 based on the composition and related data of the batch to be etched. As a result, the desired etching process can be carried out stably.

[0190] Furthermore, in the substrate processing apparatus (substrate processing system 1) according to the embodiment, if the control unit 9 determines that the concentration of silicate compound in the etching solution L in the processing tank 61 after etching of a batch of samples to be etched will reach a given threshold, at least a portion of the etching solution L in the processing tank 61 will be replaced before etching of that batch. Therefore, when etching the next batch of samples to be etched, an excessive increase in the concentration of silicate compound in the processing tank 61 can be suppressed, thus enabling stable implementation of the desired etching process.

[0191] Furthermore, in the substrate processing apparatus (substrate processing system 1) according to the embodiment, the control unit 9 supplies silicate compound to the processing tank 61 during batch etching processes. This allows etching processes to be performed under identical conditions across multiple batches.

[0192] Furthermore, in the substrate processing apparatus (substrate processing system 1) according to the embodiment, if the concentration of silica compound in the etching solution L in the processing tank 61 reaches a given threshold during a batch etching process, the control unit 9 replaces at least a portion of the etching solution L in the processing tank 61 during that batch etching process. This allows the concentration of the alkaline processing solution in the processing tank 61 to be stabilized within a given concentration range, thus enabling the desired etching process to be performed stably.

[0193] Furthermore, in the substrate processing apparatus (substrate processing system 1) according to the embodiment, the relevant data includes a standard curve showing the correlation between the concentration of the silica compound in the etching solution L in the processing tank 61 and the etching rate of the polysilicon film L2 formed on the substrate (wafer W). This allows etching processes to be performed under identical conditions across multiple batches.

[0194] Furthermore, in the substrate processing apparatus (substrate processing system 1) according to the embodiment, the control unit 9 adjusts the etching time for each batch based on the concentration of silica compound in the processing tank 61 measured by the concentration measuring unit 136. This allows etching to be performed on multiple batches under identical conditions.

[0195] Furthermore, in the substrate processing apparatus (substrate processing system 1) according to the embodiment, the concentration sensor 137 in the concentration measuring unit 136, which measures the concentration of silica compounds in the etching solution L within the processing tank 61, is a microwave plasma atomic emission spectrometer, a high-frequency inductively coupled plasma atomic emission spectrometer, or an inductively coupled high-frequency plasma mass spectrometer. This allows for the high-precision measurement of the concentration of silica compounds in the etching solution L.

[0196] Furthermore, in the substrate processing apparatus (substrate processing system 1) according to the embodiment, the processing liquid is diluted ammonia, SC1, NC2, or TMAH. This allows for efficient etching of the polysilicon film L2 formed on the surface of the wafer W.

[0197] Furthermore, in the substrate processing apparatus (substrate processing system 1) according to the embodiment, the control unit 9 controls the operation of the processing liquid supply unit 100 to keep the concentration of the processing liquid in the processing tank 61 within a given concentration range. As a result, the desired etching process can be performed stably.

[0198] Furthermore, in the substrate processing apparatus (substrate processing system 1) according to the embodiment, the temperature of the etchant L during batch etching is 40°C to 80°C. This allows for efficient etching of the polysilicon film L2 formed on the surface of the wafer W.

[0199] The embodiments of this disclosure have been described above, but this disclosure is not limited to the above embodiments. Various modifications can be made unless they depart from the spirit of this disclosure. For example, in the above embodiments, a device structure formed on wafer W is shown. Figure 2 The example shown is an example of this, but the device structure formed on the wafer W is not limited to this example.

[0200] Furthermore, in the above embodiments, an example of etching wafer W using etchant L was shown in a so-called batch process. However, this disclosure is not limited to this example, and etching wafer W using etchant L can also be performed in a so-called single-wafer process. This also improves the uniformity of the etching process of the polysilicon film L2 formed on wafer W.

[0201] It should be considered that all points in the disclosed embodiments are illustrative rather than restrictive. In fact, the above embodiments can be implemented in various ways. In addition, the above embodiments can be omitted, substituted, or modified in various ways without departing from the appended claims and their spirit.

[0202] Explanation of reference numerals in the attached figures

[0203] 1: Substrate processing system (an example of a substrate processing apparatus); 7: Control device; 9: Control unit; 10: Storage unit; 61: Processing tank; 100: Processing solution supply unit; 110: Silicate supply unit; 136: Concentration measuring unit; 137: Concentration sensor; H: Hole (an example of a recess); L: Etching solution; L2: Polycrystalline silicon film; W: Wafer (an example of a substrate).

Claims

1. A substrate processing method, comprising the following steps: Adding silica compounds to an alkaline treatment solution to generate an etching solution; and The polycrystalline silicon film formed on the substrate is etched using the etching solution.

2. The substrate processing method according to claim 1, wherein, The polycrystalline silicon film is located on the inner surface of a recess formed on the surface of the substrate. In the etching process, at least a portion of the polycrystalline silicon film located on the inner surface of the recess is etched.

3. The substrate processing method according to claim 1 or 2, wherein, The silica compound is colloidal silicon dioxide.

4. The substrate processing method according to claim 1 or 2, wherein, The silica compound is at least one of sodium silicate, potassium silicate, and calcium silicate.

5. The substrate processing method according to claim 1 or 2, wherein, The treatment solution is diluted ammonia, SC1 (a mixture of ammonia and hydrogen peroxide), NC2 (a mixture of choline solution and hydrogen peroxide), or TMAH (tetramethylammonium hydroxide).

6. A substrate processing apparatus comprising: A processing tank is used to immerse a batch of one or more substrates in an etching solution generated by adding a silica compound to an alkaline processing solution for etching. A treatment fluid supply unit supplies the treatment fluid to the treatment tank; A silica supply unit supplies the silica compound to the processing tank; A concentration measuring unit measures the concentration of the components of the etching solution stored in the processing tank; The control department, which controls all other departments; as well as The storage unit stores relevant data, which includes the correlation between the concentration of the silica compound in the etching solution within the processing tank and the etching rate of the polycrystalline silicon film formed on the substrate.

7. The substrate processing apparatus according to claim 6, wherein, The control unit adjusts the amount of silica compound supplied to the processing tank based on the composition of the batch to be etched and the relevant data.

8. The substrate processing apparatus according to claim 7, wherein, The control unit supplies the silica compound to the processing tank before the scheduled etching process of the batch.

9. The substrate processing apparatus according to claim 8, wherein, If the control unit determines that the concentration of the silica compound in the etching solution in the processing tank will reach a given threshold after the etching process of the batch to be etched, it replaces at least a portion of the etching solution in the processing tank before the etching process of that batch.

10. The substrate processing apparatus according to any one of claims 7 to 9, wherein, The control unit supplies the silica compound to the processing tank during the batch etching process.

11. The substrate processing apparatus according to claim 10, wherein, If the concentration of the silica compound in the etching solution in the processing tank reaches a given threshold during the etching process of the batch, the control unit replaces at least a portion of the etching solution in the processing tank during the etching process of that batch.

12. The substrate processing apparatus according to any one of claims 7 to 9, wherein, The relevant data includes a standard curve representing the correlation between the concentration of the silica compound in the etching solution within the processing tank and the etching rate of the polycrystalline silicon film formed on the substrate.

13. The substrate processing apparatus according to any one of claims 7 to 9, wherein, The control unit adjusts the etching time of the batch based on the concentration of the silica compound in the processing tank as measured by the concentration measuring unit.

14. The substrate processing apparatus according to any one of claims 7 to 9, wherein, The concentration sensor in the concentration measuring unit that measures the concentration of the silica compound in the etching solution in the treatment tank is a microwave plasma atomic emission spectrometer, a high-frequency inductively coupled plasma atomic emission spectrometer, or an inductively coupled high-frequency plasma mass spectrometer.

15. The substrate processing apparatus according to any one of claims 7 to 9, wherein, The treatment solution is diluted ammonia, SC1, NC2, or TMAH.

16. The substrate processing apparatus according to claim 15, wherein, The control unit controls the operation of the treatment liquid supply unit to keep the concentration of the treatment liquid in the treatment tank within a given concentration range.

17. The substrate processing apparatus according to any one of claims 7 to 9, wherein, The temperature of the etching solution used to etch the batch is 40°C to 80°C.

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