Substrate processing method and substrate processing apparatus

Abstract

To provide a technique that can efficiently etch a silicon carbonitride (SiCN) film formed on a substrate.SOLUTION: A substrate processing method according to the present disclosure includes the steps of: anodizing a silicon carbonitride (SiCN) film by applying a voltage while supplying an electrolytic solution to a substrate on which the SiCN film is formed; and, after the anodization step, removing an oxide film produced by the anodization using an etching solution.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] 2. Description of the Related Art Conventionally, there is known a technique for etching a SiN (silicon nitride) film formed on a substrate such as a semiconductor wafer (hereinafter also referred to as a wafer) with an etching solution of phosphoric acid (see Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-144175 A [Patent Document 2] JP 2013-26453 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique capable of efficiently etching a SiCN film formed on a substrate. [Means for solving the problem]

[0005] A substrate processing method according to one embodiment of the present disclosure includes a step of anodizing a SiCN film by applying a voltage while supplying an electrolytic solution to a substrate on which a SiCN film has been formed, and a step of removing an oxide film produced by the anodization using an etching solution after the anodization step. Effect of the Invention

[0006] According to the present disclosure, a SiCN film formed on a substrate can be efficiently etched. [Brief description of the drawings]

[0007] [Figure 1]FIG. 1 is a diagram showing a schematic configuration of a substrate processing system according to a first embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing a specific configuration example of the processing unit. [Diagram 3] FIG. 3 is a flowchart showing an example of a procedure of substrate processing executed by the substrate processing system according to the first embodiment. [Figure 4A] FIG. 4A is a diagram showing an example of changes in voltage value and current value during anodizing according to the first embodiment. [Figure 4B] FIG. 4B is a diagram showing an example of changes in voltage value and current value during anodizing according to the first embodiment. [Diagram 5] FIG. 5 is a diagram showing the configuration of a processing unit according to the second embodiment. [Figure 6] FIG. 6 is a diagram showing the configuration of a peripheral supply section and an application section in a processing unit according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, a detailed description will be given of a substrate processing method and a substrate processing apparatus according to the present disclosure (hereinafter, referred to as an "embodiment") with reference to the drawings. Note that the present disclosure is not limited to the embodiment. In addition, each embodiment can be appropriately combined as long as the processing contents are not contradictory. In addition, the same parts in each of the following embodiments are given the same reference numerals, and duplicated descriptions are omitted.

[0009] In addition, in the embodiments described below, expressions such as "constant", "orthogonal", "vertical" and "parallel" may be used, but these expressions do not necessarily mean "constant", "orthogonal", "vertical" and "parallel" strictly. In other words, each of the above expressions allows for deviations due to, for example, manufacturing accuracy and installation accuracy.

[0010] In addition, in the drawings referred to below, for ease of understanding, an orthogonal coordinate system may be shown in which the X-axis, Y-axis, and Z-axis directions are defined as being orthogonal to each other, and the Z-axis positive direction is the vertically upward direction. Also, the direction of rotation about the vertical axis may be referred to as the θ direction.

[0011] A technique for etching a SiN (silicon nitride) film formed on a substrate such as a semiconductor wafer (hereinafter also referred to as a wafer) with an etching solution of phosphoric acid is known. Currently, there is a study being conducted to change the SiN film used in semiconductor elements such as FinFETs (Fin Field-Effect Transistors) to a SiCN (silicon carbonitride) film.

[0012] However, because SiCN films are denser and harder than SiN films, the etching rate of SiCN films is very low with phosphoric acid and hydrofluoric acid, which are conventionally used as etching solutions for SiN films. In other words, it was very difficult to efficiently etch SiCN films formed on substrates using conventional techniques.

[0013] Therefore, there is a need to realize a technology that overcomes the above-mentioned problems and enables efficient etching of a SiCN film formed on a substrate.

[0014] (First embodiment) <Outline of the substrate processing system> First, a schematic configuration of a substrate processing system 1 according to a first embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing a schematic configuration of the substrate processing system 1 according to the first embodiment.

[0015] 1, the substrate processing system 1 includes a loading / unloading station 2 and a processing station 3. The loading / unloading station 2 and the processing station 3 are provided adjacent to each other.

[0016] The carry-in / out station 2 includes a FOUP placement section 11 and a transport section 12. On the FOUP placement section 11, a plurality of FOUPs F are placed, each of which accommodates a plurality of substrates, in the first embodiment, semiconductor wafers W (hereinafter referred to as wafers W), in a horizontal state.

[0017] The transfer section 12 is provided adjacent to the FOUP placement section 11, and includes therein a substrate transfer device 13 and a transfer section 14. The substrate transfer device 13 includes a wafer holding mechanism that holds the wafer W. The substrate transfer device 13 is capable of moving in the horizontal and vertical directions and rotating about a vertical axis, and transfers the wafer W between the FOUP F and the transfer section 14 using the wafer holding mechanism.

[0018] The processing station 3 is provided adjacent to the transport section 12. The processing station 3 includes a transport section 15 and a plurality of processing units 16. The plurality of processing units 16 are provided side by side on both sides of the transport section 15.

[0019] The transfer section 15 includes a substrate transfer device 17 therein. The substrate transfer device 17 includes a wafer holding mechanism that holds the wafer W. The substrate transfer device 17 is capable of moving in the horizontal and vertical directions and rotating about a vertical axis, and transfers the wafer W between the delivery section 14 and the processing unit 16 using the wafer holding mechanism.

[0020] The processing unit 16 performs a given substrate processing on the wafer W transferred by the substrate transfer device 17 .

[0021] The substrate processing system 1 also includes a control device 4. The control device 4 is, for example, a computer, and includes a control unit 18 and a storage unit 19. The storage unit 19 stores programs for controlling various processes executed in the substrate processing system 1. The control unit 18 controls the operation of the substrate processing system 1 by reading out and executing the programs stored in the storage unit 19.

[0022] Such a program may be recorded in a computer-readable storage medium and installed from that storage medium into the storage unit 19 of the control device 4. Examples of computer-readable storage media include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnet optical disk (MO), and a memory card.

[0023] In the substrate processing system 1 configured as described above, first, the substrate transfer device 13 in the load / unload station 2 removes the wafer W from the FOUP F placed on the FOUP placement section 11, and places the removed wafer W on the delivery section 14. The wafer W placed on the delivery section 14 is then removed from the delivery section 14 by the substrate transfer device 17 in the processing station 3, and carried into the processing unit 16.

[0024] The wafer W carried into the processing unit 16 is processed by the processing unit 16, and then carried out of the processing unit 16 by the substrate transfer device 17 and placed on the delivery section 14. Then, the processed wafer W placed on the delivery section 14 is returned to the FOUP F of the FOUP mounting section 11 by the substrate transfer device 13.

[0025] <Processing unit configuration> Next, the configuration of the processing unit 16 will be described with reference to Fig. 2. Fig. 2 is a schematic diagram showing a specific configuration example of the processing unit 16. As shown in Fig. 2, the processing unit 16 includes a chamber 20, a substrate holding unit 30, a peripheral supply unit 40, and a collection cup 50. The processing unit 16 further includes an application unit 60.

[0026] The chamber 20 accommodates the substrate holder 30, the peripheral supply unit 40, and the collection cup 50. An FFU (Fan Filter Unit) 21 is provided on the ceiling of the chamber 20. The FFU 21 forms a downflow within the chamber 20.

[0027] The substrate holding unit 30 includes a holding unit 31, a support unit 32, and a driving unit 33, and holds and rotates the wafer W. The driving unit 33 is an example of a substrate rotating mechanism. The holding unit 31 sucks the center of the back surface of the wafer W and holds the wafer W horizontally.

[0028] The support portion 32 is a member extending in the vertical direction, with its base end rotatably supported by the drive portion 33 and its tip end horizontally supporting the holding portion 31. The drive portion 33 rotates the support portion 32 around a vertical axis.

[0029] The substrate holding unit 30 rotates the support column 32 using the drive unit 33 to rotate the holding unit 31 supported by the support column 32, thereby rotating the wafer W held by the holding unit 31.

[0030] The peripheral supply unit 40 supplies an electrolytic solution, an etching solution, or DIW to the edge of the wafer W. The peripheral supply unit 40 includes a nozzle 41a, an arm 42a that horizontally supports the nozzle 41a, and a rotating / lifting mechanism 43a that rotates and raises / lowers the arm 42a.

[0031] The nozzle 41a is connected to an electrolyte supply source 46a via a valve 44a and a flow regulator 45a.

[0032] The electrolyte supplied from the electrolyte supply source 46a is any one of an acidic aqueous solution, an alkaline aqueous solution, a neutral aqueous solution, and an organic solvent containing an electrolyte. The acidic aqueous solution used as the electrolyte is, for example, hydrochloric acid (HCl), nitric acid (HNO 3 ), sulfuric acid (H 2 SO 4 ) or phosphoric acid (H 3 PO 4 The alkaline aqueous solution used as the electrolyte is, for example, ammonium hydroxide (NH 4OH), sodium hydroxide (NaOH) aqueous solution, potassium hydroxide (KOH) aqueous solution, tetramethylammonium hydroxide (TMAH) or choline aqueous solution.

[0033] The neutral aqueous solution used as the electrolyte is, for example, an aqueous sodium chloride (NaCl) solution or an aqueous potassium chloride (KCl) solution. The organic solvent containing the electrolyte used as the electrolyte is, for example, a liquid containing alcohol or a hydrocarbon and a perchlorate. The peripheral supply unit 40 is an example of an electrolyte supply unit.

[0034] Furthermore, the nozzle 41a is connected to an etching liquid supply source 46b via a valve 44b and a flow rate regulator 45b. The etching liquid supply source 46b is, for example, a tank that stores an etching liquid. The etching liquid supplied from the etching liquid supply source 46b is, for example, hydrofluoric acid (HF). In this case, the concentration of hydrofluoric acid in the etching liquid may be 0.11 wt% or more and 50 wt% or less. The temperature of the etching liquid may be 20°C or more and 80°C or less.

[0035] The etching liquid may contain, for example, either ammonium fluoride or ammonium hydrogen fluoride. The etching liquid may be, for example, a potassium hydroxide (KOH) aqueous solution, a tetramethylammonium hydroxide (TMAH) aqueous solution, or a choline aqueous solution. The peripheral edge supply unit 40 is an example of an etching liquid supply unit.

[0036] The nozzle 41a is connected to a DIW supply source 46c via a valve 44c and a flow rate regulator 45c. The DIW supply source 46c is, for example, a tank that stores DIW (DeIonized Water). The DIW is used, for example, for rinsing the wafer W.

[0037] The collection cup 50 is disposed so as to surround the holder 31, and collects the processing liquid L scattered from the wafer W due to the rotation of the holder 31. A drainage port 51 is formed in the bottom of the collection cup 50, and the processing liquid L collected by the collection cup 50 is discharged from the drainage port 51 to the outside of the processing unit 16. In addition, an exhaust port 52 is formed in the bottom of the collection cup 50, which discharges the gas supplied from the FFU 21 to the outside of the processing unit 16.

[0038] The application unit 60 includes an anode 61, a cathode 62, a power source 63, a switch 64, and an ammeter 65. The anode 61 is provided inside the holding unit 31 and is electrically connected to the wafer W. The cathode 62 is provided inside the nozzle 41b and applies a predetermined negative voltage to the electrolytic solution flowing through the nozzle 41b. The control unit 18 brings the wafer W and the cathode 62 into contact with each other via the electrolytic solution, thereby bringing the wafer W and the cathode 62 into electrical contact with each other. For example, as shown in FIG. 2, a sponge 70 configured to be capable of holding an electrolytic solution is brought into contact with the wafer W, and the electrolytic solution is supplied to the sponge 70, thereby bringing the wafer W and the cathode 62 into contact with each other via the electrolytic solution and the sponge 70. The sponge 70 is movably held by a holding mechanism (not shown).

[0039] In addition, the anode 61 is connected to the positive electrode side of a power source 63, and the cathode 62 is connected to the negative electrode side of the power source 63 via a switch 64. The control unit 18 can apply a predetermined positive voltage to the anode 61 and can apply a predetermined negative voltage to the cathode 62 by controlling the switch 64 to the on state.

[0040] The ammeter 65 is provided, for example, between the anode 61 and the power source 63 and measures the value of the current flowing between the anode 61 and the cathode 62 .

[0041] <Substrate processing details> Next, details of the substrate processing according to the first embodiment will be described with reference to Fig. 3. Fig. 3 is a flow chart showing an example of a procedure of the substrate processing executed by the substrate processing system 1 according to the first embodiment.

[0042] In the substrate processing according to the first embodiment, first, the control unit 18 controls the transport units 12, 15, etc. to load the wafer W into the processing unit 16. The wafer W is held by the holding unit 31 with the surface on which various semiconductor devices including the SiCN film are formed facing upward (step S101). That is, the wafer W according to the first embodiment has a SiCN film. The holding unit 31 also functions as an anode connected to the cathode 62 via the power source 63. Then, the control unit 18 controls the substrate holding unit 30, etc. to rotate the wafer W at a given rotation speed (step S102). Then, the control unit 18 moves the sponge 70 by a holding mechanism (not shown) to contact the peripheral portion of the wafer.

[0043] Next, the control unit 18 controls the peripheral supply unit 40 and the like to apply a voltage while supplying an electrolyte to the SiCN film formed on the edge of the wafer W, thereby performing anodization processing to anodize the SiCN film. Specifically, first, the control unit 18 controls the peripheral supply unit 40 and the like to start supplying the electrolyte at a given flow rate to the peripheral portion of the wafer W on which the SiCN film is formed (step S103). Then, the control unit 18 controls the application unit 60 and the like to start applying a voltage at a given voltage value between the anode 61 and the cathode 62 (step S104).

[0044] According to this process, carbon and silicon are ionized by anodization at the interface between the wafer W and the electrolyte in contact with the cathode 62, and the ionized carbon and silicon are dissolved into the electrolyte. The silicon then combines with oxygen generated at the same time to form a silicon oxide (SiO) film. The SiO film formed on the surface of the wafer W is electrochemically etched by the etching process described below.

[0045] Next, the control unit 18 determines whether or not to stop applying the voltage based on the measurement result of the ammeter 65 (step S105). This determination process will be described with reference to Figures 4A and 4B. Figures 4A and 4B are diagrams showing an example of the transition of the voltage value and the current value in the anodizing process according to the first embodiment.

[0046] When the control unit 18 starts applying a voltage at a voltage value V1, a current with a current value I1 flows on the wafer W. Thereafter, as the anodic oxidation progresses, an oxide film (here, a SiO film) F2 formed on the wafer W gradually becomes thicker, and accordingly, the value of the current flowing on the wafer W gradually decreases. Then, as shown in FIG. 4A, when the thickness of the oxide film F2 reaches a certain level or more, the current stops flowing through the wafer W. Therefore, the control unit 18 determines to stop applying the voltage when the current value becomes zero based on the measurement result of the ammeter 65.

[0047] 4B, for example, when only a small amount of the SiCN film F1 remains on the wafer W and the SiCN film F1 is entirely changed to an oxide film F2, the thickness of the oxide film F2 does not exceed a certain value (i.e., the current value does not become zero), but the manner in which the current value decreases changes. Specifically, a change appears in the rate of change of the current value per unit time. Therefore, based on the measurement result of the ammeter 65, the control unit 18 determines to stop the application of the voltage when the rate of change of the current value per unit time becomes equal to or less than a threshold value.

[0048] In this way, when the rate of change of the current value per unit time becomes equal to or less than the threshold value, or when the current value becomes zero (step S105, Yes), the control unit 18 controls the application unit 60 and the like to stop applying the voltage (step S106). This makes it possible to minimize the time for the anodization process, and also to prevent the anodization process from proceeding more than necessary, thereby reducing the oxidation of the wafer W.

[0049] Thereafter, the control unit 18 controls the peripheral supply unit 40 and the like to stop the supply of the electrolyte to the wafer W (step S107). Then, the control unit 18 separates the sponge 70 from the wafer W by a holding mechanism (not shown).

[0050] Next, the control unit 18 controls the peripheral supply unit 40 and the like to discharge DIW onto the anodized surface of the wafer W, and rinse the surface of the wafer W (step S108). Next, the control unit 18 controls the peripheral supply unit 40 and the like to supply an etching solution to the peripheral portion of the wafer W on which an oxide film has been generated by the anodization, and removes the oxide film (step S109).

[0051] Next, the control unit 18 controls the peripheral supply unit 40 and the like to discharge DIW onto the etched surface of the wafer W, thereby rinsing the surface of the wafer W (step S110).

[0052] Next, the control unit 18 judges whether or not the SiCN film on the wafer W has been completely removed (step S111). For example, in step S105, if the application of the voltage is stopped because the rate of change in the current value per unit time is equal to or less than the threshold value, the control unit 18 judges that the SiCN film on the wafer W has been completely removed (step S111, Yes), and proceeds to step S112. On the other hand, in step S105, if the application of the voltage is stopped because the current value is zero, the control unit 18 judges that the SiCN film on the wafer W has not been completely removed, and returns the process to step S103, where the anodization process is performed again. In this way, by repeating a series of processes including the anodization process and the etching process multiple times, it is possible to remove the SiCN film that cannot be completely removed in one go.

[0053] The number of repetitions may be determined based on the measurement value of ammeter 65 as described above, or may be set in advance.

[0054] Next, the control unit 18 controls the substrate holding unit 30 and the like to increase the rotation speed of the wafer W, thereby performing a drying process on the wafer W by spin drying (step S112). Finally, the control unit 18 controls the transfer units 12, 15 and the like to unload the wafer W from the processing unit 16 (step S113), thereby completing a series of substrate processing operations.

[0055] As described above, in the substrate processing system 1 according to the first embodiment, by applying a voltage while supplying an electrolytic solution to the SiCN film formed on the wafer W, electrons on the surface of the SiCN film on the anode side move to the cathode side, and the surface is oxidized (anodic oxidation). Then, by supplying an etching solution such as hydrofluoric acid to the oxide film generated by the anodization, the oxide film can be easily removed. Therefore, the SiCN film formed on the wafer W can be efficiently etched.

[0056] Second embodiment In the first embodiment, an example in which the anode 61 and the wafer W are directly connected to each other has been described, but the present invention is not limited to such an example. For example, the anode 61 and the wafer W may be connected to each other via an electrolytic solution supplied to the wafer W in the same manner as the cathode 62. Hereinafter, such an example will be described with reference to Figs. 5 and 6. Fig. 5 is a diagram showing the configuration of a processing unit 16 according to the second embodiment. Fig. 6 is a diagram showing the configuration of a peripheral supply unit 40 and an application unit 60 in the processing unit 16 according to the second embodiment.

[0057] The peripheral edge supply unit 40 includes a plurality of (here, two) nozzles 41a, 41b, arms 42a, 42b that horizontally support the nozzles 41a, 41b, respectively, and pivoting and lifting mechanisms 43a, 43b that pivot and lift the arms 42a, 42b, respectively.

[0058] Nozzle 41a is connected to electrolyte supply source 46a via valve 44a and flow regulator 45a, while nozzle 41b is connected to electrolyte supply source 46a via valve 44d and flow regulator 45d.

[0059] 6, the control unit 18 (see FIG. 1) uses the nozzle 41a and the nozzle 41b of the peripheral supply unit 40 to discharge the electrolytic solution to different positions on the edge of the rotating wafer W. The electrolytic solution discharged from the nozzle 41a and the nozzle 41b is discharged without interruption up to the edge of the wafer W.

[0060] The anode 61 is provided inside the nozzle 41a and applies a predetermined positive voltage to the electrolyte flowing through the nozzle 41a. The cathode 62 is provided inside the nozzle 41b and applies a predetermined negative voltage to the electrolyte flowing through the nozzle 41b.

[0061] In addition, the anode 61 is connected to the positive electrode side of a power source 63, and the cathode 62 is connected to the negative electrode side of the power source 63 via a switch 64. The control unit 18 can apply a predetermined positive voltage to the anode 61 and can apply a predetermined negative voltage to the cathode 62 by controlling the switch 64 to the on state.

[0062] As in the first embodiment, by performing the anodization process, carbon and silicon are ionized by the anodization at the interface between the wafer W and the electrolyte in contact with the cathode 62, and the ionized carbon and silicon are dissolved into the electrolyte. The silicon then combines with oxygen generated at the same time to form a silicon oxide (SiO) film. Thereafter, the SiO film formed on the surface of the wafer W is electrochemically etched by the etching process. Therefore, the SiCN film formed on the wafer W can be efficiently etched.

[0063] (Other embodiments) Although an example of performing an etching process after anodization on a SiCN film formed on a wafer W has been described here, the present invention is not limited to this, and similar effects can be obtained by similar processes on other films formed on the wafer W. For example, the same effects can be obtained on any one of a SiC film, a SiN film, a SiOC film, and a SiOCN film formed on the wafer W.

[0064] In the first embodiment, the cathode 62 is located inside the nozzle 41a. However, the present invention is not limited to this. For example, the cathode 62 may be located inside the sponge .

[0065] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. Indeed, the above-described embodiments may be embodied in various forms. In addition, the above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims.

[0066] The present disclosure can have the following configurations. (1) a step of applying a voltage to the substrate on which the SiCN film is formed while supplying an electrolytic solution to anodize the SiCN film; a step of removing an oxide film formed by the anodization using an etching solution after the anodization step; A substrate processing method comprising: (2) The substrate processing method according to (1), wherein the electrolytic solution is any one of an acidic aqueous solution, an alkaline aqueous solution, a neutral aqueous solution, and an organic solvent containing an electrolyte. (3) The acidic aqueous solution is hydrochloric acid, nitric acid, sulfuric acid or phosphoric acid, The alkaline aqueous solution is an aqueous solution of ammonium hydroxide, an aqueous solution of sodium hydroxide, an aqueous solution of potassium hydroxide, an aqueous solution of tetramethylammonium hydroxide or an aqueous solution of choline; The neutral aqueous solution is a sodium chloride aqueous solution or a potassium chloride aqueous solution, The substrate processing method according to (2), wherein the organic solvent containing an electrolyte is a liquid containing an alcohol or a hydrocarbon and a perchlorate. (4) The substrate processing method according to any one of (1) to (3), wherein the etching liquid is hydrofluoric acid. (5) The substrate processing method according to (4), wherein the concentration of hydrofluoric acid in the etching solution is 0.11 wt % or more and 50 wt % or less. (6) The substrate processing method according to any one of (1) to (5), wherein the etching solution contains one of ammonium fluoride and ammonium hydrogen fluoride. (7) The substrate processing method according to any one of (1) to (6), wherein the etching solution has a temperature of 20° C. or higher and 80° C. or lower. (8) The substrate processing method according to any one of (1) to (7), wherein a series of steps including the anodizing step and the removing step are repeated multiple times. (9) The substrate processing method according to any one of (1) to (8), wherein the anodizing step includes contacting the substrate with a cathode via the electrolytic solution to establish electrical continuity between the substrate and the cathode. (10) The substrate processing method according to (9), wherein the anodizing step includes contacting the substrate with a sponge and supplying the electrolyte to the sponge, thereby contacting the substrate with the cathode via the electrolyte and the sponge. (11) A step of holding the substrate on a holding part as an anode connected to a cathode via a power source before the step of anodizing. The substrate processing method according to any one of (1) to (10), further comprising: (12) The substrate processing method according to any one of (1) to (11), wherein the anodizing step stops the application of voltage when a rate of change in a value of a current flowing through the substrate per unit time becomes equal to or less than a threshold value, or when the current value becomes zero. (13) The substrate processing method according to any one of (1) to (12), wherein the anodizing step is performed on the SiCN film formed on an edge portion of the substrate. (14) a step of applying a voltage to a substrate on which any one of a SiC film, a SiN film, a SiOC film, and a SiOCN film has been formed, while supplying an electrolytic solution to the substrate, thereby anodizing the film; a step of removing an oxide film formed by the anodization using an etching solution after the anodization step; A substrate processing method comprising: (15) a substrate holder for holding a substrate on which a SiCN film is formed; an electrolyte supply unit that supplies an electrolyte to the substrate held by the substrate holder; an application unit that applies a voltage to the substrate held by the substrate holder; an etching liquid supply unit that supplies an etching liquid to the substrate held by the substrate holding unit; Control unit and Equipped with The control unit is a process of controlling the electrolytic solution supply unit and the application unit to apply a voltage while supplying an electrolytic solution to the substrate to anodize the SiCN film, and a process of controlling the etching solution supply unit to remove an oxide film produced by the anodization using the etching solution after the anodization. [Explanation of symbols]

[0067] W wafer 1. Substrate Processing System 16 Processing Unit 18 Control Unit 30 Board holding part 40 Periphery supply section 41a Nozzle 60 Applicator 61 Anode 62 Cathode

Claims

1. a step of applying a voltage to a substrate on which a SiCN film has been formed while supplying an electrolytic solution to the substrate, thereby anodizing the SiCN film; a step of removing an oxide film formed by the anodization using an etching solution after the anodization step; A substrate processing method comprising:

2. 2. The substrate processing method according to claim 1, wherein the electrolytic solution is any one of an acidic aqueous solution, an alkaline aqueous solution, a neutral aqueous solution, and an organic solvent containing an electrolyte.

3. The acidic aqueous solution is hydrochloric acid, nitric acid, sulfuric acid or phosphoric acid, The alkaline aqueous solution is an aqueous solution of ammonium hydroxide, an aqueous solution of sodium hydroxide, an aqueous solution of potassium hydroxide, an aqueous solution of tetramethylammonium hydroxide or an aqueous solution of choline; The neutral aqueous solution is a sodium chloride aqueous solution or a potassium chloride aqueous solution, 3. The substrate processing method according to claim 2, wherein the organic solvent containing an electrolyte is a liquid containing an alcohol or a hydrocarbon and a perchlorate.

4. The substrate processing method according to claim 1 , wherein the etching solution is hydrofluoric acid.

5. 5. The substrate processing method according to claim 4, wherein a concentration of hydrofluoric acid in the etching solution is not less than 0.11 wt % and not more than 50 wt %.

6. The substrate processing method according to claim 1 , wherein the etching solution contains one of ammonium fluoride and ammonium hydrogen fluoride.

7. The temperature of the etching solution is 20° C. or higher and 80° C. or lower. The method of claim 1 .

8. The substrate processing method according to claim 1 , further comprising repeating a series of steps including the anodizing step and the removing step a plurality of times.

9. 2. The substrate processing method according to claim 1, wherein the anodizing step comprises bringing the substrate and the cathode into contact with each other via the electrolytic solution, thereby establishing electrical continuity between the substrate and the cathode.

10. The substrate processing method according to claim 9 , wherein the anodizing step includes contacting the substrate with a sponge and supplying the electrolyte to the sponge, thereby contacting the substrate with the cathode via the electrolyte and the sponge.

11. A step of holding the substrate on a holding part as an anode connected to a cathode via a power source before the step of anodizing. The method of claim 1 , further comprising:

12. 2. The substrate processing method according to claim 1, wherein the anodizing step stops the application of voltage when a rate of change in a current value flowing through the substrate per unit time becomes equal to or less than a threshold value, or when the current value becomes zero.

13. 2. The substrate processing method according to claim 1, wherein the anodizing step is performed on the SiCN film formed on an edge portion of the substrate.

14. a step of applying a voltage to a substrate on which any one of a SiC film, a SiN film, a SiOC film, and a SiOCN film has been formed, while supplying an electrolytic solution to the substrate, thereby anodizing the film; a step of removing an oxide film formed by the anodization using an etching solution after the anodization step; A substrate processing method comprising:

15. a substrate holder for holding a substrate on which a SiCN film is formed; an electrolyte supply unit that supplies an electrolyte to the substrate held by the substrate holder; an application unit that applies a voltage to the substrate held by the substrate holder; an etching liquid supply unit that supplies an etching liquid to the substrate held by the substrate holding unit; Control unit and Equipped with The control unit is a process of controlling the electrolytic solution supply unit and the application unit to apply a voltage while supplying an electrolytic solution to the substrate to anodize the SiCN film, and a process of controlling the etching solution supply unit to remove an oxide film produced by the anodization using the etching solution after the anodization.

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