Substrate processing method and substrate processing apparatus

Abstract

To improve uniformity in the etching process of polysilicon films formed on a substrate. [Solution] A substrate processing method according to one aspect of the present disclosure includes the steps of: adding a silicate compound to an alkaline processing solution to produce an etching solution; and etching a polysilicon film formed on a substrate with the etching solution.

Description

[Technical Field]

[0001] The embodiments of the disclosure relate to a substrate processing method and a substrate processing apparatus. [Background technology]

[0002] Conventionally, a technique is known for etching a polysilicon film formed on a substrate using an alkaline processing solution (see Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-41076 [Overview of the project] [Problems that the invention aims to solve]

[0004] This disclosure provides a technology that can improve the uniformity of the etching process of a polysilicon film formed on a substrate. [Means for solving the problem]

[0005] A substrate processing method according to one aspect of the present disclosure includes the steps of: adding a silicate compound to an alkaline processing solution to produce an etching solution; and etching a polysilicon film formed on a substrate with the etching solution. [Effects of the Invention]

[0006] According to this disclosure, the uniformity of the etching process of a polysilicon film formed on a substrate can be improved. The effects described herein are not necessarily limited, and any of the effects described herein may be included. [Brief explanation of the drawing]

[0007] [Figure 1]Figure 1 is a schematic block diagram showing the configuration of the substrate processing system according to the embodiment. [Figure 2] Figure 2 is an enlarged cross-sectional view showing an example of the surface structure of a wafer according to the embodiment. [Figure 3] Figure 3 is a schematic block diagram showing the configuration of the etching apparatus according to the embodiment. [Figure 4] Figure 4 is a flowchart showing an example of the control processing procedure performed by the substrate processing system according to the embodiment. [Figure 5] Figure 5 shows an example of the change in the concentration of silicate compound in the treatment tank during the etching process according to this embodiment. [Figure 6] Figure 6 shows the relationship between the concentration of the silicate compound added to the etching solution and the BT ratio. [Figure 7] Figure 7 shows another example of the change in the concentration of silicate compound in the treatment tank during the etching process according to the embodiment. [Figure 8] Figure 8 shows another example of the change in the concentration of silicate compound in the treatment tank during the etching process according to the embodiment. [Figure 9] Figure 9 shows another example of the change in the concentration of silicate compound in the treatment tank during the etching process according to the embodiment. [Figure 10] Figure 10 shows another example of the change in the concentration of silicate compound in the treatment tank during the etching process according to the embodiment. [Figure 11] Figure 11 is a flowchart showing another example of the control processing procedure performed by the substrate processing system according to the embodiment. [Modes for carrying out the invention]

[0008] Hereinafter, referring to the accompanying drawings, embodiments of the substrate processing method and the substrate processing apparatus disclosed in the present application will be described in detail. Note that the present disclosure is not limited by the embodiments shown below. Also, the drawings are schematic, and it should be noted that the dimensional relationships between elements, the ratios of the elements, etc. may be different from the actual ones. Furthermore, there may be parts where the dimensional relationships and ratios between the drawings are different from each other.

[0009] Conventionally, a technique for performing an etching process on a polysilicon film formed on a substrate by using an alkaline processing liquid has been known. However, in the above conventional technique, the difference between the etching amount of the polysilicon film on the opening side of the hole formed in the substrate and the etching amount of the polysilicon film on the bottom side of the hole may be large.

[0010] Therefore, it is expected to realize a technique that can overcome the above problems and improve the uniformity in the etching process of the polysilicon film formed on the substrate, for example, the uniformity of the etching amount in the depth direction of the hole formed in the substrate.

[0011] <Configuration of the substrate processing system> First, the configuration of the substrate processing system 1 according to the embodiment will be described while referring to FIGS. 1 and 2. FIG. 1 is a schematic block diagram showing the configuration of the substrate processing system 1 according to the embodiment. The substrate processing system 1 is an example of a substrate processing apparatus.

[0012] As shown in FIG. 1, the substrate processing system 1 according to the embodiment includes a carrier loading / unloading unit 2, a lot forming unit 3, a lot placement unit 4, a lot transfer unit 5, a lot processing unit 6, and a control device 7.

[0013] The carrier loading / unloading unit 2 includes a carrier stage 20, a carrier transfer mechanism 21, carrier stocks 22 and 23, and a carrier mounting table 24.

[0014] The carrier stage 20 holds multiple carriers C transported from the outside. A carrier C is a container that holds multiple (for example, 25) wafers W arranged vertically in a horizontal position. The carrier transport mechanism 21 transports the carriers C between the carrier stage 20, carrier stocks 22 and 23, and carrier mounting table 24.

[0015] Here, the configuration of the wafer W to be etched in the substrate processing system 1 according to the embodiment will be described with reference to Figure 2. Figure 2 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.

[0016] As shown in Figure 2, the wafer W to be etched in the substrate processing system 1 (see Figure 1) according to the embodiment has a substrate S, a silicon oxide film L1, a polysilicon film L2, and a silicon nitride film L3.

[0017] In the wafer W according to this embodiment, a single layer of silicon oxide film L1 is located on the surface of the wafer W, which is made of silicon or the like. Furthermore, a single layer of polysilicon film L2 is located on the surface of this silicon oxide film L1.

[0018] Furthermore, multiple silicon oxide films L1 and multiple silicon nitride films L3 are arranged alternately in multiple layers on the surface of the polysilicon film L2. Holes H are provided in the laminate of silicon oxide film L1, polysilicon film L2, and silicon nitride film L3 described above. Holes H are an example of recesses.

[0019] On the inner surface of hole H, silicon oxide film L1, silicon nitride film L3, silicon oxide film L1, and polysilicon film L2 are stacked in this order. That is, when wafer W is processed by substrate processing system 1, the polysilicon film L2 is exposed on the inner surface of hole H.

[0020] In the etching process according to this embodiment, a portion of the polysilicon film L2 located on the inner surface of the hole H is etched.

[0021] Returning to the explanation of Figure 1, multiple wafers W before processing are transported from the carrier C placed on the carrier mounting table 24 to the lot processing unit 6 by the substrate transport mechanism 30, which will be described later. Also, multiple processed wafers W are transported from the lot processing unit 6 to the carrier C placed on the carrier mounting table 24 by the substrate transport mechanism 30.

[0022] The lot formation unit 3 has a substrate transport mechanism 30 and forms lots. A lot consists of multiple (for example, 50) wafers W that are processed simultaneously by combining wafers W housed in one or more carriers C.

[0023] Multiple wafers W forming a single lot are arranged with their surfaces facing each other and at a certain distance apart. In this disclosure, a single lot is not limited to being composed of multiple wafers W; a single lot may be composed of a single wafer W.

[0024] The substrate transport mechanism 30 transports multiple wafers W between the carrier C placed on the carrier mounting table 24 and the lot mounting section 4.

[0025] The lot placement unit 4 has a lot transport table 40, which temporarily places (holds) lots that are transported between the lot formation unit 3 and the lot processing unit 6 by the lot transport unit 5. The lot transport table 40 has a placement table 41 for placing lots formed in the lot formation unit 3 before processing, and a placement table 42 for placing lots that have been processed in the lot processing unit 6. Multiple wafers W for one lot are placed on the placement table 41 and the placement table 42 in an upright position, arranged front to back.

[0026] The lot transport unit 5 has a lot transport mechanism 50 that transports lots between the lot placement unit 4 and the lot processing unit 6, and within the lot processing unit 6. The lot transport mechanism 50 has a rail 51, a movable body 52, and a substrate holder 53.

[0027] The rail 51 is positioned along the X-axis direction, spanning the lot mounting section 4 and the lot processing section 6. The movable body 52 is configured to move along the rail 51 while holding a plurality of wafers W. The substrate holder 53 is located on the movable body 52 and holds a plurality of wafers W arranged front to back in an upright position.

[0028] The lot processing unit 6 performs etching, cleaning, drying, and other processes on multiple wafers W in one lot all at once. The lot processing unit 6 has two etching processing units 60, a cleaning processing unit 70, a cleaning processing unit 80, and a drying processing unit 90, all positioned along the rail 51.

[0029] The etching apparatus 60 performs etching on multiple wafers W in one lot at once. The cleaning apparatus 70 performs cleaning on multiple wafers W in one lot at once. The cleaning apparatus 80 performs cleaning on the substrate holder 53. The drying apparatus 90 performs drying on multiple wafers W in one lot at once. Note that the number of etching apparatuses 60, cleaning apparatuses 70, cleaning apparatuses 80 and drying apparatuses 90 is not limited to the example in Figure 1.

[0030] The etching apparatus 60 comprises an etching tank 61, a rinsing tank 62, and substrate lifting mechanisms 63 and 64.

[0031] The processing tank 61 is capable of accommodating one lot of wafers W arranged in an upright position, and stores the etching solution (hereinafter also referred to as "etching solution"). Details of the processing tank 61 will be described later.

[0032] A processing solution (such as deionized water) for rinsing is stored in the processing tank 62. Multiple wafers W that form a lot are held in an upright position, arranged front to back, in the substrate lifting mechanisms 63 and 64.

[0033] The etching apparatus 60 holds the lot transported by the lot transport unit 5 with the substrate lifting mechanism 63 and performs etching by immersing it in the etching solution L (see Figure 2) in the processing tank 61.

[0034] The etched lot in the processing tank 61 is transported to the processing tank 62 by the lot transport unit 5. The etching apparatus 60 then holds the transported lot with the substrate lifting mechanism 64 and performs rinsing by immersing it in the rinsing solution in the processing tank 62. The lot that has been rinsed in the processing tank 62 is transported to the processing tank 71 of the cleaning apparatus 70 by the lot transport unit 5.

[0035] The cleaning apparatus 70 comprises a cleaning treatment tank 71, a rinsing treatment tank 72, and substrate lifting mechanisms 73 and 74. A cleaning chemical solution is stored in the cleaning treatment tank 71.

[0036] A rinsing treatment tank 72 stores a rinsing treatment solution (such as deionized water). Multiple wafers W for one lot are held in an upright position, arranged front to back, in the substrate lifting mechanisms 73 and 74.

[0037] The cleaning apparatus 70 holds the lots transported by the lot transport unit 5 with the substrate lifting mechanism 73 and performs cleaning by immersing them in the cleaning solution in the processing tank 71. The lots that have been cleaned in the processing tank 71 are transported to the processing tank 72 by the lot transport unit 5.

[0038] The cleaning apparatus 70 holds the lot transported from the processing tank 71 with the substrate lifting mechanism 74 and performs rinsing by immersing it in the rinsing solution in the processing tank 72. The lot that has been rinsed in the processing tank 72 is transported to the processing tank 91 of the drying apparatus 90 by the lot transport unit 5.

[0039] The drying apparatus 90 comprises a processing tank 91 and a substrate lifting mechanism 92. A processing gas for drying is supplied to the processing tank 91. Multiple wafers W for one lot are held in an upright position, arranged front to back, in the substrate lifting mechanism 92.

[0040] The drying apparatus 90 holds the lots transported by the lot transport unit 5 with the substrate lifting mechanism 92 and performs drying using a drying gas supplied into the processing tank 91. The lots that have been dried in the processing tank 91 are transported to the lot placement unit 4 by the lot transport unit 5.

[0041] The cleaning apparatus 80 supplies a cleaning solution to the substrate holder 53 of the lot transport mechanism 50, and further supplies a drying gas to perform the cleaning process on the substrate holder 53.

[0042] Furthermore, the substrate processing system 1 includes a control device 7. The control device 7 is, for example, a computer and comprises a control unit 9 and a storage unit 10. The storage unit 10 stores programs that control 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.

[0043] Such a program may have been recorded on a computer-readable storage medium and installed from that storage medium to the storage unit 10 of the control device 7. Examples of computer-readable storage mediums include hard disks (HDs), flexible disks (FDs), compact disks (CDs), magnetic optical disks (MOs), and memory cards.

[0044] <Configuration of etching apparatus> Next, the configuration of the etching apparatus 60 that performs the etching process on the wafer W will be described with reference to Figure 3. Figure 3 is a schematic block diagram showing the configuration of the etching apparatus 60 according to the embodiment.

[0045] The etching apparatus 60 comprises a processing liquid supply unit 100, a silicate 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.

[0046] In the following embodiments, an example of an alkaline treatment solution is shown using SC1, which is a mixture of ammonia water and hydrogen peroxide water. However, the alkaline treatment solution in this disclosure is not limited to SC1.

[0047] The processing liquid supply unit 100 includes an ammonia water supply unit 101, a hydrogen peroxide water supply unit 102, an HDIW supply unit 103, and a CDIW supply unit 104.

[0048] The ammonia water supply unit 101 includes an ammonia water supply source 101a, an ammonia water supply path 101b, and a flow rate regulator 101c.

[0049] The ammonia water supply source 101a is, for example, a tank that stores ammonia water (ammonia aqueous solution, NH4OH). The ammonia water supply channel 101b connects the ammonia water supply source 101a to the outer tank 122 of the treatment tank 61 and supplies ammonia water from the ammonia water supply source 101a to the outer tank 122.

[0050] The flow regulator 101c is located in the ammonia water supply path 101b and regulates the flow rate of ammonia water supplied to the outer tank 122. The flow regulator 101c includes an on-off valve, a flow control valve, and a flow meter.

[0051] 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 rate regulator 102c.

[0052] The hydrogen peroxide water supply source 102a is, for example, a tank for storing hydrogen peroxide water (hydrogen peroxide aqueous solution, H2O2). The hydrogen peroxide water supply channel 102b connects the hydrogen peroxide water supply source 102a to the outer tank 122 and supplies hydrogen peroxide water from the hydrogen peroxide water supply source 102a to the outer tank 122.

[0053] The flow regulator 102c is located in the hydrogen peroxide water supply path 102b and regulates the flow rate of hydrogen peroxide water supplied to the outer tank 122. The flow regulator 102c includes an on-off valve, a flow control valve, and a flow meter.

[0054] The HDIW supply unit 103 supplies high-temperature DIW (Deionized Water) to the outer tank 122 in order 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 rate regulator 103c.

[0055] The HDIW supply source 103a is, for example, a tank for storing high-temperature DIW. The HDIW supply line 103b connects the HDIW supply source 103a to the outer tank 122 and supplies high-temperature DIW from the HDIW supply source 103a to the outer tank 122.

[0056] The flow regulator 103c is located in the HDIW supply path 103b and adjusts the amount of high-temperature DIW supplied to the outer tank 122. The flow regulator 103c includes an on-off valve, a flow control valve, and a flow meter.

[0057] The flow regulator 103c adjusts the supply rate of the high-temperature DIW, thereby adjusting the temperature of the etching solution L, the concentration of SC1, and the concentration of the silicate compound in the etching apparatus 60.

[0058] The CDIW supply unit 104 supplies room temperature DIW to the inner tank 121 of the processing tank 61 in order 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 rate regulator 104c.

[0059] The CDIW supply source 104a is, for example, a tank that stores DIW at room temperature. The CDIW supply line 104b connects the CDIW supply source 104a to the inner tank 121 and supplies room temperature DIW from the CDIW supply source 104a to the inner tank 121.

[0060] The flow regulator 104c is located in the CDIW supply path 104b and adjusts the amount of room temperature DIW supplied to the inner tank 121. The flow regulator 104c includes an on-off valve, a flow control valve, and a flow meter.

[0061] The flow regulator 104c adjusts the supply rate of DIW at room temperature, thereby adjusting the temperature of the etching solution L, the concentration of SC1, and the concentration of the silicate compound in the etching apparatus 60.

[0062] The silicate supply unit 110 supplies silicate compounds, which are raw materials for the etching solution L, to the substrate processing unit 120. The silicate supply unit 110 includes a silicate supply source 110a, a silicate supply path 110b, and a supply amount regulator 110c.

[0063] The silicate source 110a is, for example, a tank for storing silicate compounds. The silicate compounds stored in the silicate source 110a include at least one of silicic acid and silicate.

[0064] The silicic acid contained in the silicic acid compound according to the embodiment is, for example, colloidal silica. The silicate contained in the silicic acid compound according to the embodiment is, for example, at least one of sodium silicate, potassium silicate, and calcium silicate.

[0065] The silicate supply channel 110b connects the silicate supply source 110a and the confluence 101d located in the ammonia water supply channel 101b, supplying silicate compounds from the silicate supply source 110a to the ammonia water supply channel 101b.

[0066] The supply rate regulator 110c is located in the silicate supply passage 110b and adjusts the amount of silicate compound supplied to the ammonia water supply passage 101b.

[0067] In this embodiment, the silicate compound is supplied to the ammonia water supply channel 101b, and the silicate compound is supplied to the substrate processing unit 120 while being dissolved in the ammonia water. This suppresses the retention of silica particles in the piping.

[0068] Furthermore, this disclosure is not limited to the case where the silicate compound is supplied from the silicate source 110a to the treatment tank 61 via the ammonia water supply channel 101b. For example, in this disclosure, the silicate compound may be supplied from the silicate source 110a to the treatment tank 61 via the HDIW supply channel 103b. In this case, the silicate compound is supplied to the treatment tank 61 while dissolving in the high-temperature DIW. This also helps to suppress the residue of silica particles in the piping.

[0069] Furthermore, in this disclosure, the silicate compound may be supplied directly from the silicate supply source 110a to the outer tank 122. This allows for precise adjustment of the concentration of the silicate compound in the treatment tank 61.

[0070] The substrate processing unit 120 immerses multiple wafers W (i.e., lots) in an etching solution L generated by adding a silicate compound to an alkaline processing solution, thereby performing an etching process on the multiple wafers W.

[0071] The substrate processing unit 120 comprises a processing tank 61, a substrate lifting mechanism 63, a circulation path 130, and an etching solution discharge unit 140. The processing tank 61 has an inner tank 121, an outer tank 122, and a liquid level sensor 123.

[0072] The inner tank 121 is a tank for immersing multiple wafers W in etching solution L, and contains the etching solution L for immersion. The inner tank 121 has an opening 121a at its top, and the etching solution L is stored up to the vicinity of the opening 121a.

[0073] In the inner tank 121, multiple wafers W are immersed in etching solution L using a substrate lifting mechanism 63, and etching is performed on these multiple wafers W. The substrate lifting mechanism 63 is configured to be able to move up and down and holds multiple wafers W in a vertical position, arranged front to back.

[0074] The outer tank 122 is positioned outside the inner tank 121 so as to surround it, and receives the etching solution L flowing out from the opening 121a of the inner tank 121. As shown in Figure 3, the liquid level in the outer tank 122 is maintained lower than the liquid level in the inner tank 121.

[0075] The liquid level sensor 123 measures the height of the etching solution L stored in the outer tank 122. The control unit 9 (see Figure 1) according to this embodiment can measure the amount of etching solution L stored in the processing tank 61 based on the height of the outer tank 122 measured by the liquid level sensor 123.

[0076] This is because the liquid volume is always constant since the inside of the inner tank 121 and the circulation path 130 are filled with etching solution L. Therefore, the total liquid volume of the processing tank 61 can be determined by measuring the liquid volume inside the outer tank 122 based on the measurement value of the liquid level sensor 123.

[0077] 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 a discharge nozzle 124 located inside the inner tank 121.

[0078] The circulation path 130 has, in order from the outer tank 122 side, a pump 131, a heater 132, a filter 133, and a branching section 134.

[0079] Pump 131 forms a circulating flow of etching solution L sent from the outer tank 122 to the inner tank 121 via the circulation path 130. The etching solution L also flows back into the outer tank 122 by overflowing from the opening 121a of the inner tank 121.

[0080] In this way, a circulating flow of etching solution L is formed within the substrate processing unit 120. Specifically, this circulating flow is formed in the outer tank 122, the circulation path 130, and the inner tank 121.

[0081] The heater 132 adjusts the temperature of the etching solution L circulating through the circulation path 130. The filter 133 filters the etching solution L circulating through the circulation path 130.

[0082] A branching channel 135 branches off from the branching section 134. This branching channel 135 connects the branching section 134 to the outer tank 122. A concentration measuring unit 136 is located in the branching channel 135. The concentration measuring unit 136 is stored in the processing tank 61 and measures the concentration of the components of the etching solution L flowing through the branching channel 135.

[0083] The concentration measuring unit 136 includes, for example, a concentration sensor 137 and a concentration sensor 138. The concentration sensor 137 measures, for example, the concentration of silicate compounds among the components of the etching solution L.

[0084] The concentration sensor 138 measures, for example, the concentration of the alkaline processing solution among the components of the etching solution L. The signal generated by the concentration measuring unit 136 is transmitted to the control device 7 (see Figure 1).

[0085] The etching solution discharge unit 140 discharges the etching solution L to the drain DR when replacing all or part of the etching solution L used in the etching process. The etching solution discharge unit 140 includes a discharge passage 140a, a flow regulator 140b, and a cooling tank 140c.

[0086] The discharge passage 140a is connected to the circulation passage 130. The flow regulator 140b is located in the discharge passage 140a and adjusts the discharge volume of the etching solution L. The flow regulator 140b includes an on-off valve, a flow control valve, and a flow meter, etc.

[0087] The cooling tank 140c temporarily stores and cools the etching solution L that has flowed through the discharge passage 140a. In the cooling tank 140c, the discharge rate of the etching solution L is regulated by the flow regulator 140b.

[0088] <Embodiment> Next, the details of the etching process according to the embodiment will be described with reference to Figures 4 to 11. Figure 4 is a flowchart showing an example of the control process procedure performed by the substrate processing system 1 according to the embodiment.

[0089] In the control process according to this embodiment, first, the control unit 9 controls the etching solution discharge unit 140 and the like to discharge the used etching solution L stored in the processing tank 61 from the processing tank 61 (step S101).

[0090] Next, the control unit 9 controls the processing liquid supply unit 100 and the like to supply SC1, which is an alkaline processing liquid, to the processing tank 61 (step S102). In 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 concentrations of ammonia water and hydrogen peroxide water in the processing tank 61 reach a given concentration.

[0091] Next, the control unit 9 controls the silicate supply unit 110 and the like to add the silicate compound to SC1 in the treatment tank 61 (step S103). Then, as shown in Figure 5, the concentration of the silicate compound in the treatment tank 61 increases from time T02 when the process in step S103 begins. Figure 5 is a diagram showing an example of the change in the concentration of the silicate compound in the treatment tank 61 during the etching process according to this embodiment.

[0092] In Figure 5, the treatment liquid supply process described in step S102 is performed from time T01 to time T02. Also, in the example in Figure 5, the concentration of the silicate compound is almost zero at time T01, and this concentration is maintained until time T02.

[0093] Returning to the explanation of Figure 4, the control unit 9 then determines whether the concentration of the silicate compound in the processing tank 61 has reached a given concentration (for example, concentration C1 as shown in Figure 5) (step S104).

[0094] Then, if the concentration of the silicate compound in the processing tank 61 reaches a given concentration (step S104, Yes), the control unit 9 considers that the etching solution L according to the embodiment has been produced and loads a lot consisting of multiple wafers W into the processing tank 61 (step S105).

[0095] For example, as shown in Figure 5, when the concentration of the silicate compound in the treatment tank 61 reaches a given concentration C1 at time T03, the control unit 9 terminates the silicate compound addition process. As a result, the concentration of the silicate compound in the treatment tank 61 is maintained at the given concentration C1.

[0096] On the other hand, if the concentration of the silicate compound in the treatment tank 61 has not reached a given concentration (step S104, No), the process returns to step S103.

[0097] Following the process in step S105, the control unit 9 immerses the lot that has been brought into the processing tank 61 in the etching solution L and performs an etching process on the multiple wafers W contained in the lot (step S106).

[0098] As described above, in this embodiment, the polysilicon film L2 located on the surface of the wafer W is etched using an etching solution L which is an alkaline processing solution (for example, SC1) to which a silicate compound has been added.

[0099] This improves 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 hole H shown in Figure 2 and the etching amount of the polysilicon film L2 located at the opening of hole H. The reason for this is explained below.

[0100] In the etching process of the polysilicon film L2 using alkaline SC1, hydrogen peroxide reacts within the SC1 as shown in the following chemical formulas (1) and (2), producing oxygen molecules O2 and hydroxide ions OH. - This is generated. H2O2 + OH -⇔ H2O + OOH - ···(1) H2O2 + OOH - → H2O + O2 + OH - ···(2)

[0101] Also, in the etching process using SC1, inside SC1, ammonium hydroxide reacts as shown in the following chemical formula (3), generating hydroxide ions OH - which are produced. NH4OH → NH4 + + OH - ···(3)

[0102] Then, the oxygen molecule O2 generated in the above chemical formula (2) reacts with the polysilicon film L2, generating silicon oxide SiO2 as shown in the following chemical formula (4). Si + O2 → SiO2 ···(4)

[0103] Furthermore, the hydroxide ions OH generated in the above chemical formulas (1) and (3) - react with the silicon oxide SiO2 generated in the above chemical formula (4) and the polysilicon film L2, generating silicic acid Si(OH)4 as shown in the following chemical formulas (5) and (6). SiO2 + 2OH - + 2H + → Si(OH)4 ···(5) Si + 2H2O + 2OH - → H2 + Si(OH)4 ···(6)

[0104] In this way, in the etching solution L, the reactions of the above chemical formulas (1) to (6) continue to occur, gradually increasing the concentration of silicic acid in the etching solution L. As a result, as the etching process progresses, the reactions of the above chemical formulas (5) and (6) become less likely to proceed to the right side.

[0105] Thus, when etching a polysilicon film L2 with an alkaline treatment solution, the etching rate decreases as the concentration of silicate increases. While this example uses SC1 as the alkaline treatment solution, similar chemical reactions occur with other alkaline treatment solutions.

[0106] Furthermore, when etching the polysilicon film L2 located on the inner surface of hole H with an alkaline treatment solution, as in conventional technology, new treatment solution is relatively easily supplied to the opening of hole H, making the aforementioned decrease in etching rate less likely to occur.

[0107] On the other hand, at the bottom of hole H, new processing solution is less readily supplied than at the opening, so the silica concentration tends to increase more easily, which makes the aforementioned decrease in etching rate more likely to occur.

[0108] Therefore, in the conventional technology, the ratio of the etching rate at the bottom of hole H to the etching rate at the opening of hole H (also referred to in this disclosure as the "BT (Bottom to Top) ratio") decreased, resulting in poor uniformity of the etching process.

[0109] However, in this embodiment, the silicate compound is added to the alkaline treatment solution from the beginning of the etching process. As a result, the aforementioned decrease in etching rate is relatively likely to occur even at the openings of holes H from the start of the etching process.

[0110] Therefore, in this embodiment, compared to the conventional technology, a balance is achieved between the frequency of etching reactions at the opening of hole H and the frequency of etching reactions at the bottom of hole H.

[0111] Therefore, according to this embodiment, it is possible to improve the uniformity in the etching process of the polysilicon film L2, for example, the uniformity between the amount of etching of the polysilicon film L2 located at the bottom of the hole H and the amount of etching of the polysilicon film L2 located at the opening of the hole H.

[0112] Figure 6 shows the relationship between the concentration of the silicate compound added to the etching solution L and the BT ratio. As shown in Figure 6, when the concentration of the silicate compound is 0 ppm, that is, when no silicate compound is added to the initially alkaline etching solution, the BT ratio is considerably lower than the ideal value of 1.0.

[0113] On the other hand, as in the embodiment, when etching is performed with etching solution L to which 80 ppm or 160 ppm of silicate compound is added from the beginning, the BT ratio approaches the ideal value of 1.0, indicating an improvement in the uniformity of the etching process.

[0114] Thus, in this embodiment, by etching the wafer W with an etching solution L containing a silicate compound added to an alkaline processing solution, the uniformity of the etching process of the polysilicon film L2 can be improved.

[0115] Furthermore, in the embodiment, in the process of generating etching solution L by adding a silicate compound to an alkaline treatment solution, the concentration of the silicate compound may be 400 ppm or less. This further improves the uniformity of the etching process of the polysilicon film L2.

[0116] Returning to the explanation of Figure 4, in parallel with the etching process in step S106, the control unit 9 controls the silicate supply unit 110 and the like to add silicate compounds to the etching solution L in the treatment tank 61 (step S107).

[0117] For example, in this embodiment, as shown in Figure 5, the silicate compound is preferably added to the etching solution L such that it passes through a calibration curve connecting a given concentration C1 at the start time T04 of the etching process and a given concentration C2 at the end time T05 of the etching process.

[0118] Furthermore, correlation data, which includes data on this calibration curve and shows 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, is stored in the storage unit 10 in advance.

[0119] Figures 7 and 8 show another example of the change in the concentration of silicate compound in the processing tank 61 during the etching process according to the embodiment. As shown in Figure 7, when one lot consists of one wafer W, the amount of silicate dissolved in the etching solution L during the etching process is less than when one lot consists of 50 wafers W, so the slope of the increase in the concentration of silicate compound becomes smaller.

[0120] As a result, when one lot consists of one wafer W, the etching rate may become significantly higher, especially in the later stages of the etching process, compared to when one lot consists of 50 wafers W.

[0121] Therefore, in this embodiment, the control unit 9 checks the configuration of the lot to be processed in advance, and if the lot to be processed consists of a small amount of wafers W, it increases the amount of silicate compound added in step S107 compared to when the lot consists of a large amount of wafers W.

[0122] This allows etching to be performed with a similar silicate compound concentration progression throughout the entire etching process, even when etching lots consisting of any number of sheets. Therefore, according to this embodiment, etching can be performed under uniform conditions across multiple lots.

[0123] Furthermore, as shown in Figure 8, when 100 layers of multilayer film are located on the surface of the wafer W, the amount of silicic acid that dissolves in the etching solution L during the etching process is less than when 400 layers of multilayer film are located, resulting in a smaller slope in the increase of the silicic acid compound concentration.

[0124] As a result, when 100 layers of multilayer film are located on the surface of wafer W, the etching rate may become significantly higher, especially in the later stages of the etching process, compared to when 400 layers of multilayer film are located on the surface of wafer W.

[0125] Therefore, in this embodiment, the control unit 9 checks the configuration of the lot to be processed in advance, and if the wafer W included in the lot to be processed consists of a small number of layers, the amount of silicate compound added in step S107 is increased compared to when the wafer W consists of a large number of layers.

[0126] This allows etching to be performed with a similar silicate compound concentration progression throughout the entire etching process, even when etching wafers W composed of any number of layers. Therefore, according to this embodiment, etching can be performed under uniform conditions across multiple lots.

[0127] Returning to the explanation of Figure 4, following the processing in steps S106 and S107 described above, the control unit 9 determines whether a given processing time has elapsed (step S108).

[0128] Then, if the given processing time has elapsed (step S108, Yes), the control unit 9 considers that the etching process of the lot is complete and removes the lot from the processing tank 61 (step S109), ending the series of control processes.

[0129] On the other hand, if the given processing time has not elapsed (step S108, No), the process returns to steps S106 and S107.

[0130] The control unit 9 then performs rinsing, washing, and drying on the lot discharged from the processing tank 61, and subsequently discharges the lot from the lot processing unit 6 to the carrier loading / unloading unit 2.

[0131] In Figure 5, from time T05, when the etching process for one lot is completed, the process described in step S101 above is performed as part of the etching process for the next lot to be processed, in which the used etching solution L stored in the processing tank 61 is discharged from the processing tank 61. As a result, as shown in Figure 5, the concentration of silicate compounds in the processing tank 61 decreases.

[0132] If the used etching solution L is not completely discharged, silicate compounds may remain in the treatment tank 61, and the concentration of silicate compounds may not return to zero at time T01 shown in Figure 5. In this case, in this embodiment, the treatment shown in Figure 9 or Figure 10 may be performed.

[0133] Figures 9 and 10 show another example of the change in the concentration of the silicate compound in the treatment tank 61 during the etching process according to the embodiment. In the example of Figure 9, if the concentration of the silicate compound in the treatment tank 61 is greater than zero (concentration C3) at time T01, the control unit 9 performs the processes of steps S102 and S103 described above with the same supply and addition amounts as when the concentration of the silicate compound in the treatment tank 61 is zero.

[0134] As shown in Figure 9, at time T03, the concentration of the silicate compound in the treatment tank 61 becomes a concentration C4 which is greater than the given concentration C1. In this case, the control unit 9 reduces the concentration of the silicate compound in the treatment tank 61 by discharging the etching solution L from the etching solution discharge unit 140 and replenishing SC1 from the treatment solution supply unit 100.

[0135] This allows the concentration of the silicate compound in the treatment tank 61 to be set to a given concentration C1 at time T04 when the etching process begins.

[0136] Furthermore, in the example shown in Figure 10, if the concentration of the silicate compound in the treatment tank 61 is greater than zero (concentration C3) at time T01, the control unit 9 performs the process in step S102 described above with the same supply amount as when the concentration of the silicate compound in the treatment tank 61 is zero.

[0137] Then, in the process of step S103, the control unit 9 reduces the amount of silicate compound added compared to when the concentration of silicate compound in the treatment tank 61 is zero. As a result, at the time T03 when the process of step S103 is completed, the concentration of silicate compound in the treatment tank 61 can be set to a given concentration C1.

[0138] Furthermore, in this embodiment, the alkaline treatment solution used as a raw material for the etching solution L may be diluted ammonia water, SC1, NC2 (a mixture of choline aqueous solution and hydrogen peroxide solution), or TMAH (tetramethylammonium hydroxide). This allows for efficient etching of the polysilicon film L2 formed on the surface of the wafer W.

[0139] Furthermore, in this embodiment, the silicate compound that serves as the raw material for the etching solution L may contain at least one of silicic acid and silicate. This allows the silicate compound to be easily dissolved in the alkaline treatment solution, thus enabling the etching solution L to be produced simply.

[0140] In addition, in this embodiment, the control unit 9 may adjust the etching time applied to the lot based on the concentration of the silicate compound in the treatment tank 61. For example, if the concentration of the silicate compound in the treatment tank 61 is higher than the expected concentration, the control unit 9 may extend the etching time beyond the expected time.

[0141] Furthermore, if the concentration of silicate compounds in the treatment tank 61 remains lower than the expected concentration, the control unit 9 may shorten the etching time to a shorter duration than the expected time.

[0142] In this way, by adjusting the etching time according to the concentration of the silicate compound in the treatment tank 61, etching can be performed under uniform conditions across multiple lots.

[0143] Furthermore, in this embodiment, the temperature of the etching solution L when etching the lot may be 40°C to 80°C. This allows for efficient etching of the polysilicon film L2 formed on the surface of the wafer W.

[0144] Furthermore, in this embodiment, the concentration sensor 137 for measuring the concentration of silicate compounds in the etching solution L may 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 accurate measurement of the concentration of silicate compounds in the etching solution L.

[0145] In addition, in this embodiment, if the control unit 9 determines that the concentration of the silicate compound in the processing tank 61 has reached a given threshold after the etching process of the next lot to be processed, it may replace the etching solution L in the processing tank 61 before etching that lot.

[0146] This prevents an excessive increase in the concentration of silicate compounds in the treatment tank 61 when the next lot to be processed is etched, thus enabling the desired etching process to be carried out stably.

[0147] In this embodiment, the control unit 9 may also control the operation of the processing solution supply unit 100 so that the concentration of the alkaline processing solution in the processing tank 61 remains within a given concentration range. For example, if the concentration of the processing solution in the processing tank 61 exceeds a given concentration range, the control unit 9 may discharge the etching solution L from the etching solution discharge unit 140 and replenish it with a lower concentration processing solution or HDIW from the processing solution supply unit 100.

[0148] Furthermore, if the concentration of the processing solution in the processing tank 61 falls below a given concentration range, the control unit 9 may discharge the etching solution L from the etching solution discharge unit 140 and replenish it with a higher concentration processing solution from the processing solution supply unit 100.

[0149] In this way, by stabilizing the concentration of the alkaline treatment solution in the treatment tank 61 within a given concentration range, the desired etching process can be stably carried out.

[0150] Figure 11 is a flowchart showing another example of the control processing procedure performed by the substrate processing system 1 according to the embodiment.

[0151] In the control process shown in the example in Figure 11, first, the control unit 9 controls the etching solution discharge unit 140 and the like 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 and the like to supply the alkaline processing solution SC1 to the processing tank 61 (step S202).

[0152] Next, the control unit 9 controls the silicic acid supply unit 110 and the like to add the silicic acid compound to SC1 in the treatment tank 61 (step S203).

[0153] Next, the control unit 9 determines whether the concentration of the silicate compound in the processing tank 61 has reached a given concentration (step S204). If the concentration of the silicate compound in the processing tank 61 has reached a given concentration (step S204, Yes), the control unit 9 loads the lot into the processing tank 61 (step S205).

[0154] On the other hand, if the concentration of the silicate compound in the treatment tank 61 has not reached a given concentration (step S204, No), the process returns to step S203.

[0155] Following the process in step S205, the control unit 9 immerses the lot brought into the processing tank 61 in the etching solution L and performs an etching process on multiple wafers W contained in the lot (step S206). The processes in steps S201 to S206 described above are the same as the processes in steps S101 to S106 described above, so a detailed explanation is omitted.

[0156] In parallel with the etching process in step S206, the control unit 9 controls the silicate supply unit 110 and the like to add silicate compounds to the etching solution L in the treatment tank 61 (step S207).

[0157] Next, the control unit 9 determines whether the concentration of silicate compound in the treatment tank 61 has risen excessively (step S208). If the concentration of silicate compound in the treatment tank 61 has risen excessively (step S208, Yes), the control unit 9 supplies alkaline treatment solution to the treatment tank 61 to lower the concentration of silicate compound (step S209), and then returns to the process in step S207.

[0158] On the other hand, if the concentration of silicate compounds in the treatment tank 61 does not rise excessively (step S208, No), the process proceeds to step S210.

[0159] Following the processing in steps S206 and S208, the control unit 9 determines whether a given processing time has elapsed (step S210). If the given processing time has elapsed (step S210, Yes), the control unit 9 considers that the etching process of the lot is complete and removes the lot from the processing tank 61 (step S211), ending the series of control processes.

[0160] On the other hand, if the given processing time has not elapsed (step S210, No), the process returns to steps S206 and S207.

[0161] As explained above, in the example of Figure 11, if the concentration of the silicate compound in the treatment tank 61 reaches a given threshold during the etching process of a certain lot, at least a portion of the etching solution L in the treatment tank 61 may be replaced during the etching process of that lot.

[0162] This allows the concentration of the alkaline treatment solution in the treatment tank 61 to be stabilized within a given concentration range, thereby enabling the desired etching process to be carried out stably.

[0163] The substrate processing method according to the embodiment includes a step of generating an etching solution L (steps S102, S103) and an etching step (step S106). The step of generating the etching solution L (steps S102, S103) involves adding a silicate compound to an alkaline processing solution to generate the etching solution L. The etching step (step S106) includes etching the polysilicon film L2 formed on the substrate (wafer W) with the etching solution L. This makes it possible to improve the uniformity of the etching process of the polysilicon film L2 formed on the wafer W.

[0164] Furthermore, in the substrate processing method according to 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). The etching step (step S106) etches at least a portion of the polysilicon film L2 located on the inner surface of the recess (hole H). This improves the uniformity between the amount of etching of the polysilicon film L2 located at the bottom of the hole H and the amount of etching of the polysilicon film L2 located at the opening of the hole H.

[0165] Furthermore, in the substrate processing method according to the embodiment, the silicate compound is colloidal silica. This allows for the easy production of the etching solution L.

[0166] Furthermore, in the substrate processing method according to the embodiment, the silicate compound is at least one of sodium silicate, potassium silicate, and calcium silicate. This allows for the easy production of the etching solution L.

[0167] Furthermore, in the substrate processing method according to the embodiment, the processing solution is diluted ammonia water, SC1, NC2, or TMAH. This allows for efficient etching of the polysilicon film L2 formed on the surface of the wafer W.

[0168] Furthermore, the substrate processing apparatus (substrate processing system 1) according to the embodiment comprises 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 performs etching by immersing a lot consisting of one or more substrates (wafers W) in an etching solution L produced by adding a silicate compound to an alkaline processing liquid. The processing liquid supply unit 100 supplies the processing liquid to the processing tank 61. The silicate supply unit 110 supplies the 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 correlation 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 makes it possible to improve the uniformity of the etching process of the polysilicon film L2 formed on the wafer W.

[0169] 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 configuration of the lot to be etched and correlation data. This makes it possible to stably perform the desired etching process.

[0170] Furthermore, in the substrate processing apparatus (substrate processing system 1) according to the embodiment, if the control unit 9 determines that the concentration of the silicate compound in the etching solution L in the processing tank 61 has reached a given threshold after etching of a lot scheduled for etching, it replaces at least a portion of the etching solution L in the processing tank 61 before etching of that lot. This prevents the concentration of the silicate compound in the processing tank 61 from rising excessively when the next lot scheduled for processing is etched, thereby enabling the desired etching process to be carried out stably.

[0171] Furthermore, in the substrate processing apparatus (substrate processing system 1) according to the embodiment, the control unit 9 supplies a silicate compound to the processing tank 61 during the etching process of a lot. This makes it possible to perform the etching process under uniform conditions across multiple lots.

[0172] Furthermore, in the substrate processing apparatus (substrate processing system 1) according to the embodiment, the control unit 9 replaces at least a portion of the etching solution L in the processing tank 61 during the etching process of a lot if the concentration of the silicate compound in the etching solution L in the processing tank 61 reaches a given threshold. This makes it possible to stabilize the concentration of the alkaline processing solution in the processing tank 61 within a given concentration range, thereby enabling the desired etching process to be carried out stably.

[0173] Furthermore, in the substrate processing apparatus (substrate processing system 1) according to the embodiment, the correlation data includes a calibration curve that shows 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 makes it possible to perform etching under uniform conditions over multiple lots.

[0174] Furthermore, in the substrate processing apparatus (substrate processing system 1) according to the embodiment, the control unit 9 adjusts the etching time applied to a lot based on the concentration of the silicate compound in the processing tank 61 measured by the concentration measuring unit 136. This makes it possible to perform etching under uniform conditions across multiple lots.

[0175] Furthermore, in the substrate processing apparatus (substrate processing system 1) according to the embodiment, the concentration sensor 137 in the concentration measurement unit 136, which measures the concentration of silicate compounds in the etching solution L in 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 accurate measurement of the concentration of silicate compounds in the etching solution L.

[0176] Furthermore, in the substrate processing apparatus (substrate processing system 1) according to the embodiment, the processing solution is diluted ammonia water, SC1, NC2, or TMAH. This allows for efficient etching of the polysilicon film L2 formed on the surface of the wafer W.

[0177] 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 so that the concentration of the processing liquid in the processing tank 61 is within a given concentration range. This makes it possible to stably perform the desired etching process.

[0178] Furthermore, in the substrate processing apparatus (substrate processing system 1) according to the embodiment, the temperature of the etching solution L when etching a lot is 40°C to 80°C. This allows for efficient etching of the polysilicon film L2 formed on the surface of the wafer W.

[0179] Although embodiments of the present disclosure have been described above, the present disclosure is not limited to the embodiments described above, and various modifications are possible without departing from the spirit thereof. For example, in the embodiments described above, the device structure formed on the wafer W is shown in the example shown in Figure 2, but the device structure formed on the wafer W is not limited to such an example.

[0180] Furthermore, although the above embodiment shows an example in which the etching process of the wafer W with the etching solution L is performed in a so-called batch process, the present disclosure is not limited to such an example, and the etching process of the wafer W with the etching solution L may 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 the wafer W.

[0181] The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. Indeed, the embodiments described above can be embodied in a variety of forms. Furthermore, the embodiments described above may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the appended claims. [Explanation of Symbols]

[0182] 1. Substrate Processing System (An Example of a Substrate Processing Device) 7 Control device 9. Control Unit 10 Storage section 61 Processing tank 100 Processing liquid supply unit 110 Silicate supply unit 136 Concentration measurement section 137 Concentration Sensor H-hole (an example of a recess) L Etching Solution L2 Polysilicon film W wafer (an example of a substrate)

Claims

1. A process of producing an etching solution by adding a silicate compound to an alkaline treatment solution, A step of etching a polysilicon film formed on a substrate with the etching solution, A substrate processing method including the following.

2. The polysilicon film is located on the inner surface of the recess formed on the surface of the substrate, The etching step involves etching at least a portion of the polysilicon film located on the inner surface of the recess. The substrate processing method according to claim 1.

3. The aforementioned silicate compound is colloidal silica. The substrate processing method according to claim 1 or 2.

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

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

6. A processing tank for etching a lot consisting of one or more substrates by immersing it in an etching solution produced by adding a silicate compound to an alkaline processing solution, A processing liquid supply unit that supplies the processing liquid to the processing tank, A silicic acid supply unit that supplies the silicic acid compound to the processing tank, A concentration measuring unit for measuring the concentration of the components of the etching solution stored in the processing tank, A control unit that controls each part, A storage unit that stores correlation data, which stores the correlation between the concentration of the silicate compound in the etching solution in the processing tank and the etching rate of the polysilicon film formed on the substrate, A substrate processing apparatus equipped with the following:

7. The control unit adjusts the amount of the silicate compound supplied to the processing tank based on the configuration of the lot scheduled for etching and the correlation data. The substrate processing apparatus according to claim 6.

8. The control unit supplies the silicate compound to the treatment tank before etching the lot that is scheduled to undergo etching. The substrate processing apparatus according to claim 7.

9. The control unit, after etching a lot scheduled for etching, determines that the concentration of the silicate compound in the etching solution in the treatment tank has reached a given threshold, and replaces at least a portion of the etching solution in the treatment tank before etching that lot. The substrate processing apparatus according to claim 8.

10. The control unit supplies the silicate compound to the treatment tank during the etching process of the lot. A substrate processing apparatus according to any one of claims 7 to 9.

11. The control unit, when the concentration of the silicate compound in the etching solution in the processing tank reaches a given threshold during the etching process of the lot, replaces at least a portion of the etching solution in the processing tank during the etching process of the lot. The substrate processing apparatus according to claim 10.

12. The correlation data includes a calibration curve that shows the correlation between the concentration of the silicate compound in the etching solution in the processing tank and the etching rate of the polysilicon film formed on the substrate. A substrate processing apparatus according to any one of claims 7 to 9.

13. The control unit adjusts the etching time applied to the lot based on the concentration of the silicate compound in the treatment tank measured by the concentration measuring unit. A substrate processing apparatus according to any one of claims 7 to 9.

14. Among the concentration measuring units, the concentration sensor for measuring the concentration of the silicate compound in the etching solution in the processing 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. A substrate processing apparatus according to any one of claims 7 to 9.

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

16. The control unit controls the operation of the processing liquid supply unit so that the concentration of the processing liquid in the processing tank is within a given concentration range. The substrate processing apparatus according to claim 15.

17. The temperature of the etching solution when etching the lot is 40°C to 80°C. A substrate processing apparatus according to any one of claims 7 to 9.

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