Substrate processing apparatus and substrate processing method

Abstract

To provide a technique capable of an etching a nobel metal film on a substrate with high accuracy.SOLUTION: A substrate processing apparatus comprises: a substrate holding part; a processing liquid supply part; a positive electrode and a negative electrode; and a control part. The substrate holding part holds the substrate. The processing liquid supply part supplies a processing liquid to the substrate held by the substrate holding part. The positive electrode and the negative electrode apply a voltage to the processing liquid supplied from the processing liquid supply part. The control part controls each part. The processing liquid supply part can discharge the processing liquid to a plurality of portions located at different positions on the substrate. The positive electrode is arranged so as to be in contact with the processing liquid at one portion. The negative electrode is arranged so as to be in contact with the processing liquid at another portion. The control part controls a voltage value between the positive electrode and the negative electrode on the basis of a current value flowing between the positive electrode and the negative electrode.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] Conventionally, a technique for etching a noble metal film such as a ruthenium (Ru) film formed on a substrate such as a semiconductor wafer (hereinafter also referred to as a wafer) is known (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a technique capable of accurately etching a noble metal film on a substrate.

Means for Solving the Problems

[0005] A substrate processing apparatus according to an aspect of the present disclosure includes a substrate holding unit, a processing liquid supply unit, an anode and a cathode, and a control unit. The substrate holding unit holds a substrate. The processing liquid supply unit supplies a processing liquid to the substrate held by the substrate holding unit. The anode and the cathode apply a voltage to the processing liquid supplied from the processing liquid supply unit. The control unit controls each unit. The processing liquid supply unit is capable of discharging the processing liquid to a plurality of locations on the substrate that are different in position from each other. The anode is disposed so as to contact the processing liquid at one of the locations. The cathode is disposed so as to contact the processing liquid at another of the locations. The control unit controls a voltage value between the anode and the cathode based on a current value flowing between the anode and the cathode.

Effects of the Invention

[0006] According to the present disclosure, a noble metal film on a substrate can be accurately etched.

Brief Description of the Drawings

[0007]

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MODE FOR CARRYING OUT THE INVENTION

[0008] Hereinafter, with reference to the accompanying drawings, embodiments of the substrate processing apparatus and the substrate processing method 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 reality. Furthermore, there may be parts where the dimensional relationships and ratios between the drawings are different from each other.

[0009] Conventionally, a technique for etching a noble metal film such as a ruthenium (Ru) film formed on a substrate such as a semiconductor wafer (hereinafter also referred to as a wafer) has been known. However, in the prior art, there has been room for further improvement in accurately etching only the noble metal film formed on the substrate.

[0010] Therefore, it is expected to realize a technique that overcomes the above problems and can accurately etch the noble metal film on the substrate.

[0011] <Overview of the Substrate Processing System> First, with reference to FIG. 1, the schematic configuration of the substrate processing system 1 according to the embodiment will be described. FIG. 1 is a diagram showing the schematic configuration of the substrate processing system 1 according to the embodiment. Note that the substrate processing system 1 is an example of a substrate processing apparatus. Hereinafter, in order to clarify the positional relationship, an X-axis, a Y-axis, and a Z-axis orthogonal to each other are defined, and the positive direction of the Z-axis is the vertically upward direction.

[0012] As shown in FIG. 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.

[0013] The loading / unloading station 2 includes a carrier placement unit 11 and a transfer unit 12. A plurality of carriers C for horizontally accommodating a plurality of substrates, in this embodiment, semiconductor wafers W (hereinafter referred to as wafers W), are placed on the carrier placement unit 11.

[0014] The transfer unit 12 is provided adjacent to the carrier placement unit 11 and includes a substrate transfer device 13 and a delivery unit 14 inside. The substrate transfer device 13 includes a wafer holding mechanism for holding the wafer W. Further, the substrate transfer device 13 is capable of moving in the horizontal and vertical directions and turning about a vertical axis, and transfers the wafer W between the carrier C and the delivery unit 14 using the wafer holding mechanism.

[0015] The processing station 3 is provided adjacent to the transfer unit 12. The processing station 3 includes a transfer unit 15 and a plurality of processing units 16. The plurality of processing units 16 are arranged side by side on both sides of the transfer unit 15.

[0016] The transfer unit 15 includes a substrate transfer device 17 inside. The substrate transfer device 17 includes a wafer holding mechanism for holding the wafer W. Further, the substrate transfer device 17 is capable of moving in the horizontal and vertical directions and turning about a vertical axis, and transfers the wafer W between the delivery unit 14 and the processing unit 16 using the wafer holding mechanism.

[0017] The processing unit 16 performs a predetermined substrate process on the wafer W transferred by the substrate transfer device 17.

[0018] Further, the substrate processing system 1 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. Programs for controlling various processes executed in the substrate processing system 1 are stored in the storage unit 19. The control unit 18 controls the operation of the substrate processing system 1 by reading and executing the programs stored in the storage unit 19.

[0019] Incidentally, such a program may be recorded on a computer-readable storage medium and installed from the storage medium into the storage unit 19 of the control device 4. Examples of the computer-readable storage medium include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magneto-optical disk (MO), a memory card, and the like.

[0020] In the substrate processing system 1 configured as described above, first, the substrate transfer device 13 of the loading / unloading station 2 takes out the wafer W from the carrier C placed on the carrier placement unit 11 and places the taken-out wafer W on the transfer unit 14. The wafer W placed on the transfer unit 14 is taken out from the transfer unit 14 by the substrate transfer device 17 of the processing station 3 and carried into the processing unit 16.

[0021] The wafer W carried into the processing unit 16 is processed by the processing unit 16, then carried out from the processing unit 16 by the substrate transfer device 17 and placed on the transfer unit 14. Then, the processed wafer W placed on the transfer unit 14 is returned to the carrier C of the carrier placement unit 11 by the substrate transfer device 13.

[0022] <Configuration of the Processing Unit> 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 processing liquid supply unit 40, and a recovery cup 50. Further, although details will be described later, the processing unit 16 further includes a voltage application unit 60 (see FIG. 3).

[0023] The chamber 20 houses the substrate holding unit 30, the processing liquid supply unit 40, and the recovery cup 50. An FFU (Fan Filter Unit) 21 is provided on the ceiling of the chamber 20. The FFU 21 forms a downflow in the chamber 20.

[0024] The substrate holding unit 30 includes a holding unit 31, a support column unit 32, and a drive unit 33, and holds and rotates the wafer W. The drive unit 33 is an example of a substrate rotation mechanism. The holding unit 31 adsorbs the bottom surface of the wafer W and horizontally holds such a wafer W.

[0025] The support column unit 32 is a member extending in the vertical direction. The base end portion is rotatably supported by the drive unit 33, and the holding unit 31 is horizontally supported at the tip end portion. The drive unit 33 rotates the support column unit 32 around the vertical axis.

[0026] Such a substrate holding unit 30 rotates the holding unit 31 supported by the support column unit 32 by rotating the support column unit 32 using the drive unit 33, thereby rotating the wafer W held by the holding unit 31.

[0027] The processing liquid supply unit 40 supplies the processing liquid L (see FIG. 3) to the peripheral edge portion Wa of the wafer W and the like. The processing liquid supply unit 40 includes a plurality (here, two) of nozzles 41a, 41b, arms 42a, 42b that horizontally support such nozzles 41a, 41b, and swing and lift mechanisms 43a, 43b that swing and lift the arms 42a, 42b, respectively.

[0028] The nozzle 41a is an example of a first nozzle and is connected to a processing liquid supply source 46 via a valve 44a and a flow rate regulator 45a. The nozzle 41b is an example of a second nozzle and is connected to the processing liquid supply source 46 via a valve 44b and a flow rate regulator 45b.

[0029] The processing liquid L supplied from the processing liquid supply source 46 is an acidic aqueous solution, a neutral aqueous solution, or an alkaline aqueous solution. The acidic aqueous solution used as this processing liquid L is hydrochloric acid (HCl), nitric acid (HNO3), sulfuric acid (H2SO4), etc. The neutral aqueous solution used as the processing liquid L is an aqueous solution of sodium chloride (NaCl), an aqueous solution of potassium chloride (KCl), etc.

[0030] In addition, the alkaline aqueous solution used as the treatment liquid L is TMAH (TetraMethylAmmonium Hydroxide), an aqueous solution of sodium hydroxide (NaOH), an aqueous solution of potassium hydroxide (KOH), an aqueous solution of ammonia (NH3), or the like.

[0031] Note that the treatment liquid L may be an organic solvent containing an electrolyte (for example, a liquid in which a salt such as a perchlorate is contained in an organic solvent such as alcohol or hydrocarbon).

[0032] The nozzles 41a and 41b individually discharge the treatment liquid L supplied from the treatment liquid supply source 46 to predetermined locations on the peripheral portion Wa of the wafer W.

[0033] The recovery cup 50 is disposed so as to surround the holding portion 31 and collects the treatment liquid L scattered from the wafer W due to the rotation of the holding portion 31. A drain port 51 is formed at the bottom of the recovery cup 50, and the treatment liquid L collected by the recovery cup 50 is discharged to the outside of the processing unit 16 through the drain port 51. Further, an exhaust port 52 for discharging the gas supplied from the FFU 21 to the outside of the processing unit 16 is formed at the bottom of the recovery cup 50.

[0034] <Configuration of the treatment liquid supply unit and the voltage application unit> Next, the configurations of the treatment liquid supply unit 40 and the voltage application unit 60 in the processing unit 16 according to the embodiment will be described with reference to FIGS. 3 to 10. FIG. 3 is a diagram showing the configurations of the treatment liquid supply unit 40 and the voltage application unit 60 in the processing unit 16 according to the embodiment.

[0035] As shown in FIG. 3, the control unit 18 (see FIG. 1) uses the nozzles 41a and 41b of the treatment liquid supply unit 40 to discharge the treatment liquid L to locations having different positions on the peripheral portion Wa of the rotating wafer W. In the embodiment, the treatment liquid L discharged from the nozzles 41a and 41b is discharged without interruption to the peripheral portion Wa of the wafer W.

[0036] In addition, the processing unit 16 according to the embodiment includes a voltage application unit 60 that applies a voltage to the processing liquid L supplied to the peripheral portion Wa of the wafer W. Such a voltage application unit 60 includes an anode 61, a cathode 62, a variable DC power supply 63, a switch 64, an ammeter 65, and a voltmeter 66.

[0037] The anode 61 is provided inside the nozzle 41a and applies a predetermined positive voltage to the processing liquid L flowing through the nozzle 41a. The cathode 62 is provided inside the nozzle 41b and applies a predetermined negative voltage to the processing liquid L flowing through the nozzle 41b.

[0038] Also, the anode 61 is connected to the positive electrode side of the variable DC power supply 63, and the cathode 62 is connected to the negative electrode side of the variable DC power supply 63 via the switch 64. The control unit 18 can apply a predetermined positive voltage to the anode 61 and a predetermined negative voltage to the cathode 62 by controlling the switch 64 to be in the on state.

[0039] The ammeter 65 is provided, for example, between the anode 61 and the variable DC power supply 63 and measures the current value flowing between the anode 61 and the cathode 62. The voltmeter 66 measures the voltage applied between the positive electrode and the negative electrode of the variable DC power supply 63.

[0040] And in the embodiment, since the processing liquid L discharged from the nozzle 41a is discharged to the peripheral portion Wa of the wafer W without interruption, a predetermined positive voltage is applied to the peripheral portion Wa of the wafer W through the processing liquid L.

[0041] Similarly, in the embodiment, since the processing liquid L discharged from the nozzle 41b is discharged to the peripheral portion Wa of the wafer W without interruption, a predetermined negative voltage is applied to the peripheral portion Wa of the wafer W through the processing liquid L.

[0042] Here, in the embodiment, the processing liquid L discharged from the nozzle 41a and the processing liquid L discharged from the nozzle 41b are arranged at different positions on the peripheral edge Wa of the rotating wafer W. That is, a gap G is provided between the processing liquid L discharged from the nozzle 41a and the processing liquid L discharged from the nozzle 41b at the peripheral edge Wa of the rotating wafer W.

[0043] The effect of such a gap G will be described with reference to FIGS. 4 and 5. FIG. 4 is a diagram for explaining the mechanism of the etching process according to the embodiment. In the example of FIG. 4, hydrochloric acid is used as the processing liquid L, and the case where a ruthenium film is formed on the surface of the wafer W is shown.

[0044] As shown in FIG. 4, at the interface between the cathode 62 and the processing liquid L, a reduction reaction of hydrogen ions (H + ) in the processing liquid L occurs due to the electrons supplied from the negative electrode of the variable DC power supply 63 to the cathode 62.

[0045] Also, at the interface between the processing liquid L in contact with the cathode 62 and the wafer W, ruthenium is ionized by anodic oxidation, and such ionized ruthenium (Ru 3+ ) dissolves in the processing liquid L. As a result, since the ruthenium film formed on the surface of the wafer W is electrochemically etched, such a ruthenium film can be efficiently etched.

[0046] Note that the electrons generated by such anodic oxidation are supplied to the processing liquid L in contact with the anode 61 through the wafer W. Then, due to such electrons, a reduction reaction of hydrogen ions (H + ) in the processing liquid L occurs at the interface between the wafer W and the processing liquid L in contact with the anode 61.

[0047] Also, at the interface between the anode 61 and the processing liquid L, an oxidation reaction of chloride ions (Cl - ) in the processing liquid L occurs. Then, the electrons generated by such an oxidation reaction are supplied to the cathode 62 through the anode 61 and the variable DC power supply 63, and the various reactions described so far are repeated.

[0048] Here, if, hypothetically, no gap G is formed between the processing liquid L discharged from nozzle 41a and the processing liquid L discharged from nozzle 41b, the electrons generated in the processing liquid L in contact with the cathode 62 are supplied to the anode 61 through the processing liquid L rather than through the wafer W.

[0049] This is because the ruthenium film formed on the wafer W has a relatively thin film thickness (about several tens of nm), so the electrical resistance is quite large, and thus it is easier for electrons to flow through the processing liquid L.

[0050] As a result, the rate of anodic oxidation of ruthenium decreases at the interface between the processing liquid L in contact with the cathode 62 and the wafer W. That is, when the gap G is not formed, it is difficult to improve the etching rate of the ruthenium film.

[0051] However, in the embodiment, since a gap G is formed between the processing liquid L discharged from nozzle 41a and the processing liquid L discharged from nozzle 41b, the electrons generated at the interface between the cathode 62 and the processing liquid L are supplied to the anode 61 through the wafer W. As a result, the rate of anodic oxidation of ruthenium on the surface of the wafer W can be increased.

[0052] Therefore, according to the embodiment, by providing the gap G, as shown in FIG. 5, the noble metal film (here, the ruthenium film) on the wafer W can be efficiently etched. FIG. 5 is a diagram showing the quality of the etching process according to the embodiment.

[0053] In addition, in the above embodiment, an example of electrochemically etching a ruthenium film with hydrochloric acid has been shown. However, the noble metal film to which the etching process according to the embodiment is applied is not limited to the ruthenium film, and the processing liquid L used is not limited to hydrochloric acid.

[0054] Further, in the embodiment, the control unit 18 controls the voltage value of the variable DC power supply 63 based on the current value flowing through the voltage application unit 60. Details of such control will be described with reference to FIG. 6.

[0055] FIG. 6 is a diagram showing an example of the transition of the voltage value and the current value in the etching process according to the embodiment. Note that the example in FIG. 6 is an example in the case where the resistance value of the noble metal film to be etched is lower than the resistance value of the underlying layer or the substrate layer existing directly below such noble metal film.

[0056] As shown in FIG. 6, in the embodiment, the control unit 18 (see FIG. 1) starts the etching process of the noble metal film on the wafer W (see FIG. 3) by applying a given voltage value V1 between the anode 61 (see FIG. 3) and the cathode 62 (see FIG. 3) from time T0.

[0057] Note that this voltage value V1 is a voltage value that can ensure a sufficient etching rate for the noble metal film. Further, since the control unit 18 applies a voltage at a given voltage value V1 between the anode 61 and the cathode 62, it performs feedback control on the output of the variable DC power supply 63 based on the voltage value measured by the voltmeter 66.

[0058] When a voltage is applied at the voltage value V1 from time T0, a current starts to flow between the anode 61 and the cathode 62 at a current value I1. On the other hand, since the film thickness of the noble metal film on the wafer W gradually decreases due to the etching process, the resistance value of the surface of the wafer W gradually increases, so the current value between the anode 61 and the cathode 62 gradually decreases from the current value I1.

[0059] Then, when the noble metal film on the wafer W changes from a continuous film to an island film near time T1, the resistance value of the surface of the wafer W increases rapidly, so the current value between the anode 61 and the cathode 62 decreases rapidly.

[0060] When the current value between the anode 61 and the cathode 62 reaches a given current value I2 that is lower than the starting current value I1 at time T2, the control unit 18 changes the voltage value applied between the anode 61 and the cathode 62 to a voltage value V2 that is lower than the voltage value V1. The current value I2 is an example of a first threshold value, and is, for example, a value that is 50% of the current value I1 which is the initial value.

[0061] Also, the changed voltage value V2 is, for example, the voltage value shown in FIG. 7. FIG. 7 is a diagram showing the relationship between the voltage value and the current value in the initial stage of the etching process according to the embodiment.

[0062] As shown in FIG. 7, in the etching process according to the embodiment, the current value and the voltage value are not linear in all ranges, and the current value increases rapidly from a specific threshold voltage or higher. That is, in the etching process according to the embodiment, when a voltage higher than such a threshold voltage is applied, the etching rate increases rapidly, so that the noble metal film can be efficiently etched.

[0063] On the other hand, in the etching process according to the embodiment, when a voltage higher than this threshold voltage is applied, there is a risk that the underlying layer or the substrate layer existing directly under the noble metal film may be erroneously etched.

[0064] Therefore, in the embodiment, the relationship between the voltage value and the current value in the initial stage of the etching process is plotted in advance as shown in FIG. 7, and the threshold voltage at which the current value rises is set as the changed voltage value V2.

[0065] Thereby, it is possible to suppress the noble metal film formed into an island shape from being excessively etched at a high etching rate and being etched down to the underlying layer or the substrate layer. Further, in the embodiment, since the noble metal film formed into an island shape can be etched at an appropriate etching rate, the noble metal film formed into an island shape can be etched without excess or deficiency.

[0066] That is, in the embodiment, by controlling the voltage value of the variable DC power supply 63 based on the current value flowing through the voltage application unit 60, the noble metal film on the wafer W can be accurately etched.

[0067] Further, in the embodiment, when the current value between the anode 61 and the cathode 62 becomes a given current value I2 that is lower than the current value I1 at the start of the process, the voltage value applied between the anode 61 and the cathode 62 is decreased from the voltage value V1 to the voltage value V2.

[0068] Thereby, the noble metal film on the wafer W can be etched more accurately, and it is possible to suppress the underlying layer or the like existing directly under the noble metal film from being erroneously etched.

[0069] Returning to the description of FIG. 6, the current value between the anode 61 and the cathode 62 that has continued to decrease after time T2 decreases at a decreasing rate near time T3, and the subsequent current value gradually decreases.

[0070] When the current value between the anode 61 and the cathode 62 becomes a given current value I3 that is lower than the current value I1 at the start of the process at time T4, the control unit 18 changes the voltage value applied between the anode 61 and the cathode 62 to zero. The current value I3 is, for example, a value of 5% of the current value I1 which is the initial value. Thereby, the noble metal film on the wafer W is removed, and the etching process according to the embodiment ends.

[0071] In this way, in the embodiment, when the current value between the anode 61 and the cathode 62 becomes a given current value I3 that is lower than the current value I1 at the start of the process, the voltage value applied between the anode 61 and the cathode 62 is decreased from the voltage value V2 to zero. Thereby, it is possible to suppress the underlying layer or the like existing directly under the noble metal film from being erroneously etched.

[0072] Further, in the embodiment, it is preferable that the control unit 18 controls the processing liquid supply unit 40 so that the discharge position of the processing liquid L becomes the peripheral edge Wa of the wafer W while rotating the wafer W by the driving unit 33. Thereby, the wafer W can be bevel-etched.

[0073] FIG. 8 is a diagram showing another example of the transition of the voltage value and the current value in the etching process according to the embodiment. The example of FIG. 8 is an example in the case where the resistance value of the noble metal film to be subjected to the etching process is higher than the resistance value of the underlying layer or the substrate layer existing directly under the noble metal film.

[0074] As shown in FIG. 8, in the embodiment, the control unit 18 (see FIG. 1) starts the etching process of the noble metal film on the wafer W (see FIG. 3) by applying a given voltage value V1 between the anode 61 (see FIG. 3) and the cathode 62 (see FIG. 3) from time T10.

[0075] Then, when a voltage is applied at the voltage value V1 from time T10, a current starts to flow between the anode 61 and the cathode 62 at a current value I4. On the other hand, since the film thickness of the noble metal film on the wafer W gradually decreases by the etching process, the resistance value on the surface of the wafer W gradually decreases, so the current value between the anode 61 and the cathode 62 gradually increases from the current value I4.

[0076] Then, when the noble metal film on the wafer W changes from a continuous film to an island film near time T11, the resistance value on the surface of the wafer W rapidly decreases, so the current value between the anode 61 and the cathode 62 rapidly increases.

[0077] Then, when the current value between the anode 61 and the cathode 62 reaches a given current value I5 higher than the current value I4 at the start of the process at time T12, the control unit 18 changes the voltage value applied between the anode 61 and the cathode 62 to a voltage value V2 lower than the voltage value V1. The current value I5 is an example of a second threshold value, and is, for example, a value twice the current value I4 which is the initial value.

[0078] Thereby, it is possible to suppress the over-etching of the noble metal film that has become an island film at a high etching rate and the etching to the underlying layer or the substrate layer. Further, in the example of FIG. 8, since the noble metal film that has become an island film can be etched at an appropriate etching rate, the noble metal film that has become an island film can be etched without excess or deficiency.

[0079] That is, in the example of FIG. 8, based on the current value flowing through the voltage application unit 60, by controlling the voltage value of the variable DC power supply 63, the noble metal film on the wafer W can be accurately etched.

[0080] Also, in the example of FIG. 8, when the current value between the anode 61 and the cathode 62 becomes a given current value I5 that is higher than the current value I4 at the start of processing, the voltage value applied between the anode 61 and the cathode 62 is decreased from the voltage value V1 to the voltage value V2.

[0081] Thereby, the noble metal film on the wafer W can be etched more accurately, and it is possible to suppress the underlying layer or the like existing directly under the noble metal film from being erroneously etched.

[0082] And the current value between the anode 61 and the cathode 62, which has been continuously increasing after time T12, has a decreasing increase rate near time T13, and the subsequent current value gradually increases.

[0083] And when the current value between the anode 61 and the cathode 62 becomes a given current value I6 that is higher than the current value I4 at the start of processing at time T14, the control unit 18 changes the voltage value applied between the anode 61 and the cathode 62 to zero. The current value I6 is, for example, three times the current value I1 which is the initial value. Thereby, the noble metal film on the wafer W is removed, and the etching process according to the embodiment ends.

[0084] In this way, in the example of FIG. 8, when the current value between the anode 61 and the cathode 62 becomes a given current value I6 that is higher than the current value I4 at the start of processing, the voltage value applied between the anode 61 and the cathode 62 is decreased from the voltage value V2 to zero. Thereby, it is possible to suppress the underlying layer or the like existing directly under the noble metal film from being erroneously etched.

[0085] Note that, in the examples shown so far, an example has been shown in which the voltage value applied between the anode 61 and the cathode 62 is controlled when the current value between the anode 61 and the cathode 62 becomes equal to or greater than a given threshold value or equal to or less than the threshold value. However, the present disclosure is not limited to such an example.

[0086] FIG. 9 is a diagram showing an example of the transition of the voltage value, the current value, and the time derivative value of the current value in the etching process according to the embodiment. The example of FIG. 9 is an example in which the resistance value of the noble metal film to be subjected to the etching process is lower than the resistance value of the underlying layer or the substrate layer existing directly below such a noble metal film.

[0087] As shown in FIG. 9, in the embodiment, the control unit 18 (see FIG. 1) applies a given voltage value V1 between the anode 61 (see FIG. 3) and the cathode 62 (see FIG. 3) from time T20 to start the etching process of the noble metal film on the wafer W (see FIG. 3).

[0088] Then, when a voltage is applied at the voltage value V1 from time T20, a current starts to flow between the anode 61 and the cathode 62 at the current value I7. On the other hand, since the film thickness of the noble metal film on the wafer W gradually decreases by the etching process, the resistance value of the surface of the wafer W gradually increases. Therefore, the current value between the anode 61 and the cathode 62 gradually decreases from the current value I7.

[0089] Therefore, as shown in FIG. 9, the time derivative value of the current value between the anode 61 and the cathode 62 becomes substantially constant at the negative time derivative value -d1.

[0090] Then, when the noble metal film on the wafer W changes from a continuous film to an island film near time T21, the resistance value of the surface of the wafer W increases rapidly. Therefore, the current value between the anode 61 and the cathode 62 and the time derivative value of the current value between the anode 61 and the cathode 62 decrease rapidly.

[0091] Then, when the time derivative value of the current value between the anode 61 and the cathode 62 becomes a given time derivative value -d2 that is lower than the time derivative value -d1 at the start of processing at time T22, the control unit 18 changes the voltage value applied between the anode 61 and the cathode 62 to a voltage value V2 that is lower than the voltage value V1. The time derivative value -d2 is an example of a third threshold value and is, for example, about -50 (mA / s).

[0092] As a result, the noble metal film that has become an island film can be prevented from being excessively etched at a high etching rate and etched down to the underlying layer or the substrate layer. Further, in the example of FIG. 9, since the noble metal film that has become an island film can be etched at an appropriate etching rate, the noble metal film that has become an island film can be etched without excess or deficiency.

[0093] That is, in the example of FIG. 9, by controlling the voltage value of the variable DC power supply 63 based on the time derivative value of the current value flowing through the voltage application unit 60, the noble metal film on the wafer W can be accurately etched.

[0094] Also, in the example of FIG. 9, when the time derivative value of the current value between the anode 61 and the cathode 62 becomes a given time derivative value -d2 that is lower than the time derivative value -d1 at the start of processing, the voltage value applied between the anode 61 and the cathode 62 is decreased from the voltage value V1 to the voltage value V2.

[0095] As a result, the noble metal film on the wafer W can be etched more accurately, and it is possible to prevent the underlying layer or the like existing directly under the noble metal film from being erroneously etched.

[0096] Then, the time derivative value between the anode 61 and the cathode 62, which continues to decrease after time T22, reaches a minimum value near time T23, and the subsequent time derivative value gradually increases.

[0097] Then, when the time derivative value of the current value between the anode 61 and the cathode 62 becomes zero at time T24, the control unit 18 changes the voltage value applied between the anode 61 and the cathode 62 to zero. As a result, the noble metal film on the wafer W is removed, and the etching process according to the embodiment ends.

[0098] Thus, in the example of FIG. 9, when the time derivative value of the current value between the anode 61 and the cathode 62 becomes zero, the voltage value applied between the anode 61 and the cathode 62 is decreased from the voltage value V2 to zero. Thereby, it is possible to suppress the underlying layer or the like existing directly under the noble metal film from being erroneously etched.

[0099] FIG. 10 is a diagram showing another example of the transition of the voltage value, the current value, and the time derivative value of the current value in the etching process according to the embodiment. The example of FIG. 10 is an example in which the resistance value of the noble metal film to be etched is higher than the resistance value of the underlying layer or the substrate layer existing directly under such a noble metal film.

[0100] As shown in FIG. 10, in the embodiment, the control unit 18 (see FIG. 1) applies a given voltage value V1 between the anode 61 (see FIG. 3) and the cathode 62 (see FIG. 3) from time T30 to start the etching process of the noble metal film on the wafer W (see FIG. 3).

[0101] Then, when a voltage is applied at the voltage value V1 from time T30, a current starts to flow between the anode 61 and the cathode 62 with a current value I8. On the other hand, since the thickness of the noble metal film on the wafer W gradually decreases by the etching process, the resistance value of the surface of the wafer W gradually decreases, so the current value between the anode 61 and the cathode 62 gradually increases from the current value I7.

[0102] Therefore, as shown in FIG. 10, the time derivative value of the current value between the anode 61 and the cathode 62 becomes substantially constant with a positive time derivative value d3.

[0103] When the noble metal film on the wafer W changes from a continuous film to an island film near time T31, the resistance value on the surface of the wafer W decreases rapidly. Therefore, the current value between the anode 61 and the cathode 62, and the time derivative value of the current value between the anode 61 and the cathode 62 increase rapidly.

[0104] When the time derivative value of the current value between the anode 61 and the cathode 62 becomes a given time derivative value d4 higher than the time derivative value d3 at the start of processing at time T32, the control unit 18 changes the voltage value applied between the anode 61 and the cathode 62 to a voltage value V2 lower than the voltage value V1. The time derivative value d4 is an example of a fourth threshold value and is, for example, about 50 (mA / s).

[0105] Thereby, it is possible to suppress the over-etching of the noble metal film that has become an island film at a high etching rate and the etching to the underlying layer or the substrate layer. Further, in the example of FIG. 10, since the noble metal film that has become an island film can be etched at an appropriate etching rate, the noble metal film that has become an island film can be etched without excess or deficiency.

[0106] That is, in the example of FIG. 10, by controlling the voltage value of the variable DC power supply 63 based on the time derivative value of the current value flowing through the voltage application unit 60, the noble metal film on the wafer W can be accurately etched.

[0107] Also, in the example of FIG. 10, when the time derivative value of the current value between the anode 61 and the cathode 62 becomes a given time derivative value d4 higher than the time derivative value d3 at the start of processing, the voltage value applied between the anode 61 and the cathode 62 is decreased from the voltage value V1 to the voltage value V2.

[0108] Thereby, the noble metal film on the wafer W can be etched more accurately, and it is possible to suppress the underlying layer or the like existing directly under the noble metal film from being erroneously etched.

[0109] Then, the time differential value between the anode 61 and the cathode 62, which continued to decrease after time T32, reached a maximum value near time T33, and the subsequent time differential value gradually decreased.

[0110] Then, when the time differential value of the current value between the anode 61 and the cathode 62 becomes zero at time T34, the control unit 18 changes the voltage value applied between the anode 61 and the cathode 62 to zero. As a result, the noble metal film on the wafer W is removed, and the etching process according to the embodiment is completed.

[0111] Thus, in the example of FIG. 10, when the time differential value of the current value between the anode 61 and the cathode 62 becomes zero, the voltage value applied between the anode 61 and the cathode 62 is decreased from the voltage value V2 to zero. Thereby, it is possible to suppress the underlying layer or the like existing directly under the noble metal film from being erroneously etched.

[0112] <Modification Example 1> Next, various modification examples of the embodiment will be described with reference to FIGS. 11 to 23. In the following various modification examples, the same parts as those in the embodiment are denoted by the same reference numerals, and redundant descriptions are omitted.

[0113] FIG. 11 is a diagram showing the configurations of the processing liquid supply unit 40 and the voltage application unit 60 in the processing unit 16 according to Modification Example 1 of the embodiment. As shown in FIG. 11, Modification Example 1 is different from the embodiment in that an optical measuring device 70 is separately provided in the processing unit 16. Such an optical measuring device 70 can measure the film thickness of the film formed on the wafer W and is, for example, an ellipsometer.

[0114] The optical measuring device 70 has, for example, a light emitting unit 71 and a light receiving unit 72, and measures the film thickness of the noble metal film on the wafer W by measuring the amount of change in polarization of the emitted light from the light emitting unit 71 and the reflected light reflected from the surface of the wafer W and received by the light receiving unit 72 for each wavelength.

[0115] And in Modification Example 1, the control unit 18 may determine whether the processing on the wafer W is being performed normally based on the film thickness of the noble metal film measured by the optical measuring instrument 70. For example, in the example shown in FIG. 6, when the current value between the anode 61 and the cathode 62 becomes the current value I3, if the film thickness measured by the optical measuring instrument 70 is zero, the control unit 18 may set the voltage value to zero.

[0116] On the other hand, in the example shown in FIG. 6, when the current value between the anode 61 and the cathode 62 becomes the current value I3, if the film thickness measured by the optical measuring instrument 70 is not zero, the control unit 18 may maintain the voltage value at the voltage value V2 and continue the etching process.

[0117] Furthermore, in this case, the control unit 18 may set the voltage value to zero at the timing when the film thickness measured by the optical measuring instrument 70 becomes zero. Thereby, the noble metal film on the wafer W can be etched with higher accuracy.

[0118] Also, in Modification Example 1, the optical measuring instrument 70 may measure a portion away from the portion where the processing liquid L is discharged (for example, the opposite side of the portion where the processing liquid L is discharged). Thereby, since the error on the film thickness meter side of the noble metal film caused by the adhesion of the processing liquid L to the surface of the wafer W can be reduced, the film thickness of the noble metal film can be measured with high accuracy.

[0119] Therefore, according to Modification Example 1, the noble metal film on the wafer W can be etched with higher accuracy. Note that in this Modification Example 1, the optical measuring instrument 70 is not limited to an ellipsometer, and various film thickness measuring instruments can be used.

[0120] <Modification Example 2> FIG. 12 is a diagram showing the configurations of the processing liquid supply unit 40 and the voltage application unit 60 in the processing unit 16 according to Modification Example 2 of the embodiment. As shown in FIG. 12, Modification Example 2 is different from the embodiment in that an imaging device 75 is separately provided in the processing unit 16. Such an imaging device 75 can image the film formed on the wafer W.

[0121] Further, in Modification 2, the control unit 18 can obtain the film thickness of such a noble metal film based on the image of the noble metal film imaged by the imaging device 75.

[0122] And in Modification 2, the control unit 18 may determine whether the processing on the wafer W is being performed normally based on the film thickness of the noble metal film obtained based on the image of the noble metal film. For example, in the example shown in FIG. 6, when the current value between the anode 61 and the cathode 62 becomes the current value I3, if the film thickness obtained based on the image of the noble metal film is zero, the voltage value may be set to zero.

[0123] On the other hand, in the example shown in FIG. 6, when the current value between the anode 61 and the cathode 62 becomes the current value I3, if the film thickness obtained based on the image of the noble metal film is not zero, the control unit 18 may maintain the voltage value at the voltage value V2 and continue the etching process.

[0124] Furthermore, in this case, the control unit 18 may set the voltage value to zero at the timing when the film thickness obtained based on the image of the noble metal film becomes zero. Thereby, the noble metal film on the wafer W can be etched with higher accuracy.

[0125] Also, in Modification 2, the imaging device 75 may image a portion away from the portion where the processing liquid L is discharged (for example, the opposite side of the portion where the processing liquid L is discharged). Thereby, since the error on the film thickness measurement side of the noble metal film caused by the adhesion of the processing liquid L to the surface of the wafer W can be reduced, the film thickness of the noble metal film can be measured accurately.

[0126] Therefore, according to Modification 2, the noble metal film on the wafer W can be etched with higher accuracy.

[0127] <Modification 3> FIG. 13 is a diagram showing the configurations of the processing liquid supply unit 40 and the voltage application unit 60 in the processing unit 16 according to Modification Example 3 of the embodiment. In the following drawings, the variable DC power supply 63, the switch 64, the ammeter 65, and the voltmeter 66 of the voltage application unit 60 may be omitted from the illustration.

[0128] As shown in FIG. 13, in Modification Example 3, it is different from the embodiment in that a nozzle 80 is separately provided in the processing unit 16. Such a nozzle 80 is an example of a third nozzle, and discharges an insulating fluid Lx having a high electrical resistance, such as DIW (deionized water) or butyl acetate, between the processing liquid L discharged from the nozzle 41a and the processing liquid L discharged from the nozzle 41b.

[0129] In Modification Example 3, the nozzle 80 can maintain a good insulating state between the processing liquid L discharged from the nozzle 41a and the processing liquid L discharged from the nozzle 41b. Therefore, according to Modification Example 3, the noble metal film on the wafer W can be etched efficiently.

[0130] <Modification Examples 4 and 5> FIG. 14 is a diagram showing the configurations of the processing liquid supply unit 40 and the voltage application unit 60 in the processing unit 16 according to Modification Example 4 of the embodiment. As shown in FIG. 14, in Modification Example 4, it is different from the embodiment in that a gas nozzle 90 is separately provided in the processing unit 16.

[0131] Such a gas nozzle 90 discharges a gas such as air or nitrogen between the processing liquid L discharged from the nozzle 41a and the processing liquid L discharged from the nozzle 41b.

[0132] In Modification Example 4, the gas nozzle 90 can more surely form a gap G between the processing liquid L discharged from the nozzle 41a and the processing liquid L discharged from the nozzle 41b. Therefore, according to Modification Example 4, the noble metal film on the wafer W can be etched more efficiently.

[0133] In the example of FIG. 14, the case where the gas nozzle 90 is provided separately from the nozzles 41a and 41b has been shown, but the configuration of the gas nozzle 90 is not limited to this example. FIG. 15 is a diagram showing the configuration of the processing liquid supply unit 40 and the voltage application unit 60 in the processing unit 16 according to Modification Example 5 of the embodiment.

[0134] As shown in FIG. 15, the gas nozzle 90 may be provided integrally with the nozzles 41a and 41b. Thereby, gas can be more reliably discharged between the processing liquid L discharged from the nozzle 41a and the processing liquid L discharged from the nozzle 41b.

[0135] <Modification Examples 6 and 7> FIG. 16 is a diagram showing the configuration of the processing liquid supply unit 40 and the voltage application unit 60 in the processing unit 16 according to Modification Example 6 of the embodiment. As shown in FIG. 16, a plurality (five in the figure) of nozzles 41b each provided with a cathode 62 may be arranged in the processing unit 16, and the processing liquid L may be individually discharged from such a plurality of nozzles 41b to the peripheral portion Wa of the wafer W.

[0136] Even in such a case, by providing a gap G between the processing liquid L discharged from the nozzle 41a and the processing liquid L discharged from the nozzle 41b, the noble metal film on the wafer W can be efficiently etched.

[0137] Also, in Modification Example 6, since the locations where the noble metal film is electrochemically etched (that is, the locations where the processing liquid L is discharged from the nozzles 41b) can be increased, the noble metal film on the wafer W can be etched more efficiently.

[0138] In the example of FIG. 16, the case where the processing liquids L discharged from adjacent nozzles 41b are arranged apart from each other has been shown, but the processing liquids L discharged from adjacent nozzles 41b do not necessarily have to be arranged apart from each other.

[0139] For example, by bringing the processing liquids L discharged from adjacent nozzles 41b into contact with each other, the noble metal film can be uniformly etched in the thus contacted processing liquid L.

[0140] Also, in the example of FIG. 16, an example of discharging the processing liquid L to a plurality of locations using a plurality of nozzles 41b has been shown, but the configuration of the nozzle 41b is not limited to this example. FIG. 17 is a diagram showing the configuration of the processing liquid supply unit 40 and the voltage application unit 60 in the processing unit 16 according to Modification Example 7 of the embodiment.

[0141] As shown in FIG. 17, a plurality (five in the figure) of discharge ports may be provided in one nozzle 41b where the cathode 62 is provided, and the processing liquid L may be individually discharged from the plurality of discharge ports to the peripheral portion Wa of the wafer W. Also by this, since the number of locations where the noble metal film is electrochemically etched can be increased, the noble metal film on the wafer W can be etched more efficiently.

[0142] <Modification Example 8> In the examples described so far, examples in which the anode 61 and the cathode 62 are respectively arranged inside the nozzle 41a and the nozzle 41b have been shown, but the arrangements of the anode 61 and the cathode 62 are not limited to this example.

[0143] FIG. 18 is a diagram showing the configuration of the processing liquid supply unit 40 and the voltage application unit 60 in the processing unit 16 according to Modification Example 8 of the embodiment. Note that in FIGS. 18 to 23, the arrangement of the anode 61 in the nozzle 41a and the arrangement of the cathode 62 in the nozzle 41b are shown in the same drawing.

[0144] Also, in the examples of FIGS. 18 to 23, since the arrangement of the cathode 62 in the nozzle 41b is the same as the arrangement of the anode 61 in the nozzle 41a, the description of the arrangement of the cathode 62 in the nozzle 41b is omitted.

[0145] As shown in FIG. 18, the anode 61 may be provided in the conductive pipe 47 that supplies the processing liquid L to the nozzle 41a. Also by this, a predetermined positive voltage can be applied to the processing liquid L flowing through the conductive pipe 47 and the nozzle 41a.

[0146] Therefore, according to the eighth modification, a predetermined positive voltage can be applied to the processing liquid L supplied from the nozzle 41a to the peripheral portion Wa of the wafer W. As the conductive pipe 47, for example, a pipe to which conductivity is imparted by adding conductive powder such as carbon to a resin material can be used.

[0147] <Modification Example 9> FIG. 19 is a diagram showing the configuration of the processing liquid supply unit 40 and the voltage application unit 60 in the processing unit 16 according to the ninth modification of the embodiment. As shown in FIG. 19, the anode 61 may be arranged so as to be in direct contact with the processing liquid L after being discharged from the nozzle 41a to the peripheral portion Wa of the wafer W.

[0148] Also by this, a predetermined positive voltage can be applied to the processing liquid L supplied from the nozzle 41a to the peripheral portion Wa of the wafer W. When the anode 61 is arranged so as to be in direct contact with the processing liquid L after being discharged to the peripheral portion Wa, a cover 67 may be provided so as to cover the side surface of such an anode 61.

[0149] In the examples described so far, an example in which the processing liquid L is directly discharged from the nozzle 41a to the peripheral portion Wa of the wafer W has been shown. However, the processing liquid L may be once held by a liquid holding member, and the held processing liquid L may be brought into contact with the peripheral portion Wa of the wafer W.

[0150] <Modification Example 10> FIG. 20 is a diagram showing the configuration of the processing liquid supply unit 40 and the voltage application unit 60 in the processing unit 16 according to the tenth modification of the embodiment. In FIG. 20, an example in which a porous body 68 is used as an example of a liquid holding member configured to be able to hold the processing liquid L is shown. Such a porous body 68 is, for example, a sponge and is arranged so as to be wound around the side surface of the anode 61.

[0151] In Modification 10, the processing liquid L is discharged from the nozzle 41a onto the porous body 68, and the porous body 68 holds the processing liquid L. Further, by bringing the porous body 68 holding the processing liquid L into contact with the peripheral portion Wa of the wafer W, a predetermined positive voltage can be applied to the processing liquid L supplied to the peripheral portion Wa of the wafer W.

[0152] Also, in Modification 10, since the etching process of the peripheral portion Wa can be performed with the processing liquid L held by the porous body 68, the amount of the processing liquid L used can be reduced.

[0153] <Modification 11> FIG. 21 is a diagram showing the configuration of the processing liquid supply unit 40 and the voltage application unit 60 in the processing unit 16 according to Modification 11 of the embodiment. As shown in FIG. 21, most of the porous body 68 may be covered with a cover 69, and the anode 61 may be disposed between the cover 69 and the porous body 68.

[0154] Also in this case, by bringing the exposed portion of the porous body 68 holding the processing liquid L into contact with the peripheral portion Wa of the wafer W, a predetermined positive voltage can be applied to the processing liquid L supplied to the peripheral portion Wa of the wafer W.

[0155] Also, in Modification 11, since the etching process of the peripheral portion Wa can be performed with the processing liquid L held by the porous body 68, the amount of the processing liquid L used can be reduced.

[0156] <Modification 12> In the examples of FIGS. 20 and 21, an example using the porous body 68 as the liquid holding member has been shown, but the liquid holding member according to the embodiment is not limited to the porous body 68. FIG. 22 is a diagram showing the configuration of the processing liquid supply unit 40 and the voltage application unit 60 in the processing unit 16 according to Modification 12 of the embodiment.

[0157] As shown in FIG. 22, in Modification 12, a liquid holding portion 41c is provided at the discharge port of the nozzle 41a. This liquid holding portion 41c is another example of a liquid holding member and has a substantially C-shaped cross section. In the liquid holding portion 41c, the processing liquid L can be held inside the concave portion 41ca by utilizing the surface tension of the processing liquid L.

[0158] Further, in Modification 12, the anode 61 is provided in the conductive pipe 47 that supplies the processing liquid L to the nozzle 41a. That is, in Modification 12, the anode 61 indirectly contacts the processing liquid L held in the liquid holding portion 41c.

[0159] Then, as shown in FIG. 22, by inserting the peripheral edge portion Wa of the wafer W into the concave portion 41ca of the liquid holding portion 41c, a predetermined positive voltage can be applied to the processing liquid L held on the peripheral edge portion Wa of the wafer W.

[0160] Moreover, in Modification 12, since the etching process of the peripheral edge portion Wa can be performed with the processing liquid L held in the liquid holding portion 41c, the usage amount of the processing liquid L can be reduced.

[0161] <Modification 13> Note that in the example of FIG. 22, the example where the anode 61 is provided in the conductive pipe 47 is shown, but the arrangement of the anode 61 is not limited to this example. FIG. 23 is a diagram showing the configuration of the processing liquid supply unit 40 and the voltage application unit 60 in the processing unit 16 according to Modification 13 of the embodiment.

[0162] As shown in FIG. 23, in Modification 13, the anode 61 is provided inside the concave portion 41ca formed in the liquid holding portion 41c. Also by this, by inserting the peripheral edge portion Wa of the wafer W into the inside of the concave portion 41ca, a predetermined positive voltage can be applied to the processing liquid L supplied to the peripheral edge portion Wa of the wafer W.

[0163] Moreover, in Modification 13, since the etching process of the peripheral edge portion Wa can be performed with the processing liquid L held in the liquid holding portion 41c, the usage amount of the processing liquid L can be reduced.

[0164] The substrate processing apparatus (substrate processing system 1) according to the embodiment includes a substrate holding unit 30, a processing liquid supply unit 40, an anode 61 and a cathode 62, and a control unit 18. The substrate holding unit 30 holds a substrate (wafer W). The processing liquid supply unit 40 supplies a processing liquid L to the substrate (wafer W) held by the substrate holding unit 30. The anode 61 and the cathode 62 apply a voltage to the processing liquid L supplied from the processing liquid supply unit 40. The control unit 18 controls each unit. The processing liquid supply unit 40 can discharge the processing liquid L at a plurality of locations on the substrate (wafer W) where the positions are different from each other. The anode 61 is arranged to contact the processing liquid L at one location. The cathode 62 is arranged to contact the processing liquid L at another location. The control unit 18 controls the voltage value between the anode 61 and the cathode 62 based on the current value flowing between the anode 61 and the cathode 62. Thereby, the noble metal film on the wafer W can be accurately etched.

[0165] Also, in the substrate processing apparatus (substrate processing system 1) according to the embodiment, when the resistance value of the film formed on the substrate (wafer W) and in contact with the processing liquid L is lower than the resistance value of the underlying layer or the substrate layer existing directly under the film, the control unit 18 reduces the voltage value when the current value reaches a given first threshold value (current value I2) lower than the current value I1 at the start of processing. Thereby, the noble metal film on the wafer W can be accurately etched.

[0166] Also, in the substrate processing apparatus (substrate processing system 1) according to the embodiment, when the resistance value of the film formed on the substrate (wafer W) and in contact with the processing liquid L is higher than the resistance value of the underlying layer or the substrate layer existing directly under the film, the control unit 18 reduces the voltage value when the current value reaches a given second threshold value (current value I5) higher than the current value I4 at the start of processing. Thereby, the noble metal film on the wafer W can be accurately etched.

[0167] Further, in the substrate processing apparatus (substrate processing system 1) according to the embodiment, when the resistance value of the film formed on the substrate (wafer W) and in contact with the processing liquid L is lower than the resistance value of the underlying layer or the substrate layer existing directly under the film, the control unit 18 reduces the voltage value when the time differential value of the current value becomes a given third threshold value (time differential value -d2) lower than the time differential value -d1 at the start of processing. Thereby, the noble metal film on the wafer W can be accurately etched.

[0168] Further, in the substrate processing apparatus (substrate processing system 1) according to the embodiment, when the resistance value of the film formed on the substrate (wafer W) and in contact with the processing liquid L is higher than the resistance value of the underlying layer or the substrate layer existing directly under the film, the control unit 18 reduces the voltage value when the time differential value of the current value becomes a given fourth threshold value (time differential value d4) higher than the time differential value d2 at the start of processing. Thereby, the noble metal film on the wafer W can be accurately etched.

[0169] Further, in the substrate processing apparatus (substrate processing system 1) according to the embodiment, the substrate holding unit 30 has a substrate rotation mechanism (drive unit 33) that rotates the held substrate (wafer W). Further, the control unit 18 controls the discharge position of the processing liquid L so that a plurality of locations become the peripheral edge Wa of the substrate (wafer W) while rotating the substrate (wafer W) by the substrate rotation mechanism (drive unit 33). Thereby, the wafer W can be bevel-etched.

[0170] Further, the substrate processing apparatus (substrate processing system 1) according to the embodiment further includes an optical measuring device 70 capable of measuring the film thickness of the film formed on the substrate (wafer W) held by the substrate holding unit 30. Further, the control unit 18 determines whether the processing on the substrate (wafer W) is being performed normally based on the film thickness of the film measured by the optical measuring device 70. Thereby, the noble metal film on the wafer W can be etched even more accurately.

[0171] Further, the substrate processing apparatus (substrate processing system 1) according to the embodiment further includes an imaging device 75 capable of imaging a film formed on a substrate (wafer W) held by the substrate holding unit 30. Further, the control unit 18 determines whether the processing on the substrate (wafer W) is being performed normally based on the film thickness of the film obtained from the image of the film imaged by the imaging device 75. Thereby, the noble metal film on the wafer W can be etched with higher accuracy.

[0172] Also, in the substrate processing apparatus (substrate processing system 1) according to the embodiment, the processing liquid supply unit 40 includes a first nozzle (nozzle 41a), a second nozzle (nozzle 41b), and a third nozzle (nozzle 80). The first nozzle (nozzle 41a) discharges the processing liquid L connected to the anode 61 onto the substrate (wafer W). The second nozzle (nozzle 41b) discharges the processing liquid L connected to the cathode 62 onto the substrate (wafer W). The third nozzle (nozzle 80) discharges an insulating fluid Lx that insulates between the processing liquid L discharged from the first nozzle (nozzle 41a) and the processing liquid L discharged from the second nozzle (nozzle 41b) onto the substrate (wafer W). Thereby, the noble metal film on the wafer W can be etched efficiently.

[0173] <Procedure of processing> Next, the procedure of the substrate processing according to the embodiment will be described with reference to FIG. 24. FIG. 24 is a flowchart showing the procedure of the substrate processing executed by the substrate processing system 1 according to the embodiment.

[0174] First, the control unit 18 controls the processing unit 16 and the like to hold and rotate the wafer W by the substrate holding unit 30 (step S101). Then, the control unit 18 controls the processing liquid supply unit 40 and the like to discharge the processing liquid L at a plurality of locations on the peripheral edge Wa of the wafer W (step S102).

[0175] Next, the control unit 18 controls the voltage application unit 60 and the like to apply a voltage between the processing liquids L discharged at a plurality of locations on the wafer W with the anode 61 and the cathode 62 (step S103). Then, the control unit 18 measures the current value flowing between the anode 61 and the cathode 62 using the ammeter 65 (step S104).

[0176] Next, the control unit 18 controls the voltage value between the anode 61 and the cathode 62 based on the current value flowing between the anode 61 and the cathode 62 (step S105), and completes a series of substrate processes.

[0177] The substrate processing method according to the embodiment includes a discharging step (step S102), an applying step (step S103), a measuring step (step S104), and a controlling step (step S105). The discharging step (step S102) discharges the processing liquid L at a plurality of locations on the substrate (wafer W) with different positions. The applying step (step S103) applies a voltage between the processing liquids L discharged at a plurality of locations on the substrate (wafer W) with different positions with the anode 61 and the cathode 62. The measuring step (step S104) measures the current value flowing between the anode 61 and the cathode 62. The controlling step (step S105) controls the voltage value between the anode 61 and the cathode 62 based on the current value. Thereby, the noble metal film on the wafer W can be accurately etched.

[0178] Also, in the substrate processing method according to the embodiment, in the controlling step (step S105), when the resistance value of the film formed on the substrate (wafer W) and in contact with the processing liquid L is lower than the resistance value of the underlying layer or the substrate layer existing directly under the film, when the current value reaches a given first threshold value (current value I2) lower than the current value I1 at the start of the process, the voltage value is decreased. Thereby, the noble metal film on the wafer W can be accurately etched.

[0179] In the substrate processing method according to the embodiment, in the control step (step S105), when the resistance value of the film formed on the substrate (wafer W) and in contact with the processing liquid L is higher than the resistance value of the underlying layer or the substrate layer existing immediately below the film, when the current value reaches a given second threshold value (current value I5) higher than the current value I4 at the start of processing, the voltage value is decreased. Thereby, the noble metal film on the wafer W can be accurately etched.

[0180] In the substrate processing method according to the embodiment, in the control step (step S105), when the resistance value of the film formed on the substrate (wafer W) and in contact with the processing liquid L is lower than the resistance value of the underlying layer or the substrate layer existing immediately below the film, when the time derivative value of the current value reaches a given third threshold value (time derivative value -d2) lower than the time derivative value -d1 at the start of processing, the voltage value is decreased. Thereby, the noble metal film on the wafer W can be accurately etched.

[0181] In the substrate processing method according to the embodiment, in the control step (step S105), when the resistance value of the film formed on the substrate (wafer W) and in contact with the processing liquid L is higher than the resistance value of the underlying layer or the substrate layer existing immediately below the film, when the time derivative value of the current value reaches a given fourth threshold value (time derivative value d4) higher than the time derivative value d3 at the start of processing, the voltage value is decreased. Thereby, the noble metal film on the wafer W can be accurately etched.

[0182] In the substrate processing method according to the embodiment, in the control step (step S105), based on the film thickness of the film obtained from the image of the film imaged by the imaging device 75 capable of imaging the film formed on the substrate, it is determined whether the processing of the substrate is being performed normally. Thereby, the noble metal film on the wafer W can be etched even more accurately.

[0183] As described above, embodiments of the present disclosure have been explained. However, the present disclosure is not limited to the above embodiments, and various modifications are possible without departing from the spirit thereof. For example, in the above embodiment, an example of ending the etching process by setting the voltage value applied between the anode 61 and the cathode 62 to zero has been shown. However, the present disclosure is not limited to such an example. For example, the etching process may be ended by stopping the discharge of the processing liquid L.

[0184] Further, in the above embodiment, an example of controlling the voltage value during the etching process in two steps (voltage values V1, V2) has been shown. However, the voltage value to be controlled is not limited to two steps, and it may be controlled in three or more steps.

[0185] It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. Indeed, the above-described embodiments can be embodied in various forms. Also, the above embodiments may be omitted, replaced, or changed in various forms without departing from the scope and spirit of the appended claims.

Explanation of Reference Numerals

[0186] W Wafer Wa Peripheral Portion 1 Substrate Processing System (an example of a substrate processing apparatus) 16 Processing Unit 18 Control Unit 30 Substrate Holding Unit 40 Processing Liquid Supply Unit 41a Nozzle (an example of a first nozzle) 41b Nozzle (an example of a second nozzle) 60 Voltage Application Unit 61 Anode 62 Cathode 70 Optical Measuring Device 75 Imaging Device 80 Nozzle (an example of a third nozzle) L Processing Liquid Lx Insulating Fluid

Claims

1. A substrate holding part for holding a substrate, A processing liquid supply part for supplying a processing liquid to the substrate held by the substrate holding part, An anode and a cathode for applying a voltage to the processing liquid supplied from the processing liquid supply part, A control part for controlling each part, comprising The processing liquid supply part can discharge the processing liquid to a plurality of locations on the substrate where the positions are different from each other, The anode is arranged so as to contact the processing liquid at one of the locations, The cathode is arranged so as to contact the processing liquid at another of the locations, The control part controls the voltage value between the anode and the cathode based on the current value flowing between the anode and the cathode, The processing liquid supply part A first nozzle for discharging the processing liquid connected to the anode onto the substrate, A second nozzle for discharging the processing liquid connected to the cathode onto the substrate, And a third nozzle for discharging an insulating fluid for insulating between the processing liquid discharged from the first nozzle and the processing liquid discharged from the second nozzle onto the substrate. A substrate processing apparatus.

2. When the resistance value of the film formed on the substrate and in contact with the processing liquid is lower than the resistance value of the underlying layer or the substrate layer existing directly under the film, and when the current value becomes a given first threshold value lower than the current value at the start of processing, the control part reduces the voltage value The substrate processing apparatus according to Claim 1.

3. When the resistance value of the film formed on the substrate and in contact with the processing liquid is higher than the resistance value of the underlying layer or the substrate layer existing directly under the film, and when the current value becomes a given second threshold value higher than the current value at the start of processing, the control part reduces the voltage value The substrate processing apparatus according to Claim 1.

4. When the resistance value of the film formed on the substrate and in contact with the processing liquid is lower than the resistance value of the underlying layer or the substrate layer existing directly below the film, the control unit reduces the voltage value when the time derivative value of the current value becomes a given third threshold value lower than the time derivative value at the start of processing. The substrate processing apparatus according to claim 1 or 2.

5. When the resistance value of the film formed on the substrate and in contact with the processing liquid is higher than the resistance value of the underlying layer or the substrate layer existing directly below the film, the control unit reduces the voltage value when the time derivative value of the current value becomes a given fourth threshold value higher than the time derivative value at the start of processing. The substrate processing apparatus according to claim 1 or 3.

6. The substrate holding unit has a substrate rotation mechanism for rotating the held substrate. While rotating the substrate by the substrate rotation mechanism, the control unit controls the discharge position of the processing liquid so that a plurality of the locations become the peripheral edge of the substrate. The substrate processing apparatus according to any one of claims 1 to 5.

7. Further provided with an optical measuring device capable of measuring the film thickness of the film formed on the substrate held by the substrate holding unit. Based on the film thickness of the film measured by the optical measuring device, the control unit determines whether the processing of the substrate is being performed normally. The substrate processing apparatus according to any one of claims 1 to 6.

8. Further provided with an imaging device capable of imaging the film formed on the substrate held by the substrate holding unit. Based on the film thickness of the film obtained from the image of the film imaged by the imaging device, the control unit determines whether the processing of the substrate is being performed normally. The substrate processing apparatus according to any one of claims 1 to 7.

9. A step of discharging a processing liquid at a plurality of locations on a substrate, each having a different position; A step of applying a voltage between an anode and a cathode between the processing liquids discharged at a plurality of locations on the substrate, each having a different position; A step of measuring a current value flowing between the anode and the cathode; A step of controlling a voltage value between the anode and the cathode based on the current value; including The discharging step is a first nozzle for discharging the processing liquid connected to the anode onto the substrate; a second nozzle for discharging the processing liquid connected to the cathode onto the substrate; and a third nozzle for discharging an insulating fluid for insulating between the processing liquid discharged from the first nozzle and the processing liquid discharged from the second nozzle onto the substrate, and is performed by a processing liquid supply unit having A substrate processing method.

10. In the controlling step, when the resistance value of the film formed on the substrate and in contact with the processing liquid is lower than the resistance value of the underlying layer or the substrate layer existing directly under the film, when the current value becomes a given first threshold value lower than the current value at the start of processing, the voltage value is decreased The substrate processing method according to claim 9.

11. In the controlling step, when the resistance value of the film formed on the substrate and in contact with the processing liquid is higher than the resistance value of the underlying layer or the substrate layer existing directly under the film, when the current value becomes a given second threshold value higher than the current value at the start of processing, the voltage value is decreased The substrate processing method according to claim 9.

12. In the controlling step, when the resistance value of the film formed on the substrate and in contact with the processing liquid is lower than the resistance value of the underlying layer or the substrate layer existing directly under the film, when the time derivative value of the current value becomes a given third threshold value lower than the time derivative value at the start of processing, the voltage value is decreased The substrate processing method according to claim 9 or 10.

13. In the step of controlling, when the resistance value of the film formed on the substrate and in contact with the processing liquid is higher than the resistance value of the underlying layer or the substrate layer existing directly under the film, when the time differential value of the current value becomes a given fourth threshold value higher than the time differential value at the start of processing, the voltage value is decreased The substrate processing method according to claim 9 or 11.

14. In the step of controlling, it is determined whether the processing of the substrate is being performed normally based on the film thickness of the film obtained from an image of the film captured by an imaging device capable of imaging the film formed on the substrate. The substrate processing method according to any one of claims 9 to 13.

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