Substrate processing method and substrate processing apparatus

Abstract

To suitably form a protective film on the surface of a metal film.SOLUTION: A substrate processing method includes the steps of removing an oxide film and forming a protective film. In the step of removing the oxide film, an oxide film removing solution having hydrogen dissolved therein is supplied to a surface of the substrate on which the metal film and other films are exposed, thereby removing the oxide film from the surface of the metal film. In the step of forming the protective film, after the step of removing the oxide film, a protective film is formed on the surface of the metal film using a film forming material that is selectively adsorbed to the metal film among the metal film and other films.SELECTED DRAWING: Figure 5

Description

Technical Field

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

Background Art

[0002] Conventionally, when a metal film and an insulating film are exposed on the surface of a substrate such as a semiconductor wafer, a technique is known in which an oxide film such as a natural oxide film is removed from the surface of the metal film, and then a protective film is selectively formed on the surface of the metal film (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 preferably forming a protective film on the surface of a metal film.

Means for Solving the Problems

[0005] A substrate processing method according to an aspect of the present disclosure includes a step of removing an oxide film and a step of forming a protective film. The step of removing the oxide film removes the oxide film from the surface of the metal film by supplying an oxide film removing liquid in which hydrogen is dissolved to the surface of a substrate on which the metal film and other films are exposed on the surface. The step of forming the protective film forms a protective film on the surface of the metal film using a film forming material that selectively adsorbs to the metal film among the metal film and other films after the step of removing the oxide film.

Effects of the Invention

[0006] According to the present disclosure, a protective film can be preferably formed on the surface of a metal film.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0008] Hereinafter, a mode (hereinafter referred to as "embodiment") for implementing a substrate processing method and a substrate processing apparatus in a substrate processing apparatus according to the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited by this embodiment.

[0009] In addition, in the embodiments shown below, expressions such as "constant", "orthogonal", "perpendicular", or "parallel" may be used, but these expressions do not necessarily require strict "constant", "orthogonal", "perpendicular", or "parallel". That is, each of the above expressions allows for deviations such as manufacturing accuracy and installation accuracy.

[0010] In addition, in each of the drawings referred to below, for the sake of easy understanding of the description, an orthogonal coordinate system may be shown that defines the X-axis direction, Y-axis direction, and Z-axis direction that are orthogonal to each other, with the positive Z-axis direction being the vertically upward direction.

[0011] <Configuration of Substrate Processing System> First, the configuration of the substrate processing system according to the embodiment will be described. FIG. 1 is a diagram showing the configuration of the substrate processing system according to the embodiment. Further, FIG. 2 is a diagram showing the configuration of the wafer according to the embodiment. In the following, 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 transfer containers (hereinafter referred to as "carriers C") capable of accommodating a plurality of wafers W in a horizontal state are placed on the carrier placement unit 11.

[0014] The transfer unit 12 is provided adjacent to the carrier placement unit 11. Inside the transfer unit 12, a substrate transfer device 201 and a delivery unit 202 are provided.

[0015] The substrate transfer device 201 includes a wafer holding mechanism for holding the wafer W. Further, the substrate transfer device 201 can move in the horizontal and vertical directions and turn around the vertical axis, and transfers the wafer W between the carrier C and the delivery unit 202 using the wafer holding mechanism.

[0016] The processing station 3 is provided adjacent to the transfer unit 12. The processing station 3 includes a transfer unit 13 and a plurality of substrate processing devices 14. The plurality of substrate processing devices 14 are arranged side by side on both sides of the transfer unit 13.

[0017] The transfer unit 13 includes a substrate transfer device 301 inside. The substrate transfer device 301 includes a wafer holding mechanism for holding the wafer W. Further, the substrate transfer device 301 can move in the horizontal and vertical directions and turn around the vertical axis, and transfers the wafer W between the delivery unit 202 and the substrate processing device 14 using the wafer holding mechanism.

[0018] The substrate processing apparatus 14 performs a protective film forming process on the wafer W. The protective film forming process is performed to selectively form a protective film on the surface of the metal film among the metal film and the insulating film exposed on the surface of the wafer W.

[0019] The substrate processing system 1 includes a control device 4. The control device 4 is a device that controls the operation of the substrate processing system 1. Such a control device 4 is, for example, a computer and includes a control unit 15 and a storage unit 16. A program for controlling various processes such as an etching process is stored in the storage unit 16. The control unit 15 controls the operation of the substrate processing system 1 by reading and executing the program stored in the storage unit 16. The control unit 15 is, for example, a CPU (Central Processing Unit) or an MPU (Micro Processor Unit), and the storage unit 16 is, for example, a ROM (Read Only Memory) or a RAM (Random Access Memory).

[0020] Note that such a program may be recorded on a computer-readable storage medium and installed from the storage medium into the storage unit 16 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), and a memory card.

[0021] In the substrate processing system 1 configured as described above, first, the substrate transfer device 201 of the loading / unloading station 2 takes out the wafer W from the carrier C and places the taken-out wafer W on the transfer unit 202. The wafer W placed on the transfer unit 202 is taken out from the transfer unit 202 by the substrate transfer device 301 of the processing station 3 and carried into the substrate processing apparatus 14, and is processed by the substrate processing apparatus 14. The processed wafer W is carried out of the substrate processing apparatus 14 by the substrate transfer device 301, placed on the transfer unit 202, and then returned to the carrier C by the substrate transfer device 201.

[0022] <Regarding substrate processing> As shown in FIG. 2, the wafer W is a silicon wafer, a compound semiconductor wafer, or the like, and a metal film M1 and an insulating film M2 (an example of other films) are exposed on the surface. The metal film M1 and the insulating film M2 are alternately formed along the plate surface of the wafer W.

[0023] The metal material for forming the metal film M1 is any one of gold, silver, copper, iron, cobalt, nickel, zinc, rhodium, ruthenium, palladium, platinum, osmium, and iridium. Note that the metal material for forming the metal film M1 may be an alloy containing at least one of gold, silver, copper, iron, cobalt, nickel, zinc, rhodium, ruthenium, palladium, platinum, osmium, and iridium. Further, the metal material for forming the metal film M1 may contain a non-metallic material such as silicon in addition to at least one of gold, silver, copper, iron, cobalt, nickel, zinc, rhodium, ruthenium, palladium, platinum, osmium, and iridium.

[0024] The insulating film M2 is, for example, an interlayer insulating film, and is formed of, for example, a silicon-based insulating film or a metal oxide film-based insulating film. As the silicon-based insulating film, for example, a silicon oxide film, a thermal silicon oxide film, a silicon nitride film, a silicon oxynitride film, or the like can be used. Further, as the metal oxide film, for example, an aluminum oxide film, a hafnium oxide film, a zirconium oxide film, or the like can be used.

[0025] The substrate processing apparatus 14 forms a protective film on the surface of the metal film M1 using a film forming material that selectively adsorbs to the metal film M1 among the metal film M1 and the insulating film M2 exposed on the surface of the wafer W.

[0026] By the way, when an oxide film such as a natural oxide film is formed on the surface of the metal film M1, there is a possibility that film formation by the film formation material may not be appropriately performed. Therefore, in the substrate processing apparatus 14 according to the embodiment, prior to the formation of the protective film on the metal film M1, an oxide film removing liquid is supplied to the surface of the wafer W to remove the oxide film such as the natural oxide film from the surface of the metal film M1.

[0027] Oxygen may be dissolved in the oxide film removing liquid used for removing the oxide film. If oxygen is dissolved in the oxide film removing liquid, after the oxide film is removed from the surface of the metal film M1, the surface of the metal film M1 may be oxidized by the oxygen dissolved in the oxide film removing liquid, and an oxide film may be formed again on the surface of the metal film M1.

[0028] Therefore, in the substrate processing apparatus 14 according to the embodiment, the oxide film is removed from the surface of the metal film M1 using an oxide film removing liquid in which hydrogen is dissolved. By using an oxide film removing liquid in which hydrogen is dissolved, the oxygen dissolved in the oxide film removing liquid reacts with hydrogen and changes to water, so that oxidation of the surface of the metal film M1 can be suppressed. Thereby, in the formation of the protective film using the film formation material, the protective film can be preferably formed on the surface of the metal film M1.

[0029] The film formation material according to the embodiment is a material containing a sulfur atom. For example, the film formation material is thiol (R 1 -SH), disulfide (R 2 -S-S-R 3 ), thiocyanate (R 4 -SCN), etc. Here, R 1 ~R 4 each independently represents a substituted or unsubstituted alkyl group. The substituted alkyl group is, for example, an alkyl group substituted with a halogen.

[0030] The sulfur atoms contained in the film-forming material can bond with a metal film M1 containing any one of gold, silver, copper, iron, cobalt, nickel, zinc, rhodium, ruthenium, palladium, platinum, osmium, and iridium. Thereby, the film-forming material can selectively form a film (hereinafter referred to as "protective film") on the surface of the metal film M1.

[0031] Note that the protective film is a single-layer film. A single-layer film is a film in which molecules are adsorbed only in one layer on the surface of an object. For example, it is formed by a molecule having a functional group that can be adsorbed only at one location of the molecule, or by dissociation of one molecule and adsorption of only one or both of the dissociated parts. That is, the protective film is a SAM (Self-Assembled Monolayer). Also, the protective film formed by the film-forming material may be a multilayer film. A multilayer film is a film formed by the laminated adsorption of molecules, for example, a molecule having a functional group that can be adsorbed at a plurality of locations of the molecule.

[0032] Also, the concentration of dissolved hydrogen in the oxide film removal liquid according to the embodiment is 1.2 ppm or more. Thereby, the oxidation of the surface of the metal film M1 can be stably suppressed.

[0033] The experimental results regarding this point are shown in FIG. 3. FIG. 3 is a diagram showing the experimental results regarding the oxide film removal liquid according to the embodiment. In the experiment of FIG. 3, DIW (deionized water) was used as a treatment liquid simulating the oxide film removal liquid. In FIG. 3, the relationship between the concentration of dissolved hydrogen in the dissolved hydrogen DIW obtained by dissolving hydrogen in DIW and the oxidation-reduction potential (ORP: Oxidation Reduction Potential) of the dissolved hydrogen DIW is shown. FIG. 3 shows the ORP measured after mixing the dissolved hydrogen DIW and the DIW left in the air atmosphere and after 3 minutes have elapsed. The ORP indicates that the higher the value, the stronger the oxidizing power.

[0034] As shown in FIG. 3, when the concentration of dissolved hydrogen is 1.2 ppm or more, the increase in ORP with respect to the standing time of DIW is smaller than when the concentration of dissolved hydrogen is less than 1.2 ppm. From this result, it can be seen that by using an oxide film removal liquid with a dissolved hydrogen concentration of 1.2 ppm or more, the oxidation of the surface of the metal film M1 is stably suppressed.

[0035] As can be seen from the above experimental results, it is preferable to use an oxide film removal liquid with a dissolved hydrogen concentration of 1.2 ppm or more for removing the oxide film formed on the surface of the metal film M1.

[0036] <Configuration of Substrate Processing Apparatus> Next, a configuration example of the substrate processing apparatus 14 will be described with reference to FIG. 4. FIG. 4 is a diagram showing the configuration of the substrate processing apparatus 14 according to the embodiment.

[0037] As shown in FIG. 4, the substrate processing apparatus 14 includes a chamber 20, a substrate holding mechanism 30, a deoxygenated atmosphere maintaining unit 40, a processing fluid supply unit 50, a lower supply unit 60, and a recovery cup 70.

[0038] The chamber 20 houses the substrate holding mechanism 30, the deoxygenated atmosphere maintaining unit 40, the processing fluid supply unit 50, the lower supply unit 60, and the recovery cup 70. 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. Specifically, the FFU 21 is connected to a downflow gas supply source 23 via a valve 22. The FFU 21 discharges a downflow gas (for example, nitrogen or dry air) supplied from the downflow gas supply source 23 into the chamber 20.

[0039] The substrate holding mechanism 30 includes a main body 31 through which an underplate 61 of a lower supply unit 60 described later is inserted, and a holding member 32 provided on the main body 31 for holding the wafer W in a state separated from the underplate 61. The holding member 32 includes a plurality of support pins 321 for supporting the back surface of the wafer W, and the wafer W is held horizontally by supporting the back surface of the wafer W on such support pins 321. Note that the wafer W is supported by the support pins 321 with the surface on which the metal film M1 or the insulating film M2 is formed facing upward.

[0040] Further, the substrate holding mechanism 30 includes a drive unit 33 for rotating the main body 31 around a vertical axis. The substrate holding mechanism 30 can rotate the wafer W held by the holding member 32 around a vertical axis by rotating the main body 31 using the drive unit 33.

[0041] Note that the substrate holding mechanism 30 is not limited to the type that supports the wafer W from below as described above, and may be a type that holds the wafer W from the side, or may be a type that adsorbs and holds the wafer W from below like a vacuum chuck.

[0042] The deoxygenated atmosphere maintaining unit 40 includes a top plate 41, an arm 42 for horizontally supporting the top plate 41, and a drive unit 43 for pivoting and lifting the arm 42.

[0043] The top plate 41 is formed to have a size that covers the surface of the wafer W. An opening 411 through which a nozzle 51 provided in the processing fluid supply unit 50 is inserted is provided at the center of the top plate 41. The processing fluid such as a film forming material is supplied from the opening 411 to the center of the wafer W. Further, the top plate 41 includes a heating unit 412.

[0044] By raising and lowering the arm 42 using the drive unit 43, such a deoxygenated atmosphere maintaining unit 40 can change the distance between the top plate 41 and the wafer W. Specifically, the deoxygenated atmosphere maintaining unit 40 moves the top plate 41 between a processing position that is close to the surface of the wafer W and covers the upper part of the wafer W, and a retracted position that is separated from the surface of the wafer W and opens the upper part of the wafer W.

[0045] The processing fluid supply unit 50 includes a nozzle 51, an arm 52 that horizontally supports the nozzle 51, and a drive unit 53 that pivots and raises and lowers the arm 52.

[0046] The nozzle 51 is connected to the hydrogen dissolution unit 111. The hydrogen dissolution unit 111 is connected to an oxide film removal liquid supply source 113 via a flow rate adjuster 112. The oxide film removal liquid supplied from the oxide film removal liquid supply source 113 is an etching liquid capable of removing an oxide film such as a natural oxide film formed on the metal film M1. As such an etching liquid, for example, dilute hydrochloric acid or the like is used. Further, the hydrogen dissolution unit 111 is connected to a hydrogen supply source 115 via a flow rate adjuster 114.

[0047] The hydrogen dissolution unit 111 dissolves hydrogen supplied from the hydrogen supply source 115 in the oxide film removal liquid supplied from the oxide film removal liquid supply source 113 to generate an oxide film removal liquid in which hydrogen is dissolved. Dissolution of hydrogen in the oxide film removal liquid is realized, for example, using a hollow fiber or the like. The oxide film removal liquid in which hydrogen is dissolved in the hydrogen dissolution unit 111 is discharged from the nozzle 51.

[0048] Further, the nozzle 51 is connected to the hydrogen dissolution unit 121. The hydrogen dissolution unit 121 is connected to a rinse liquid supply source 123 via a flow rate adjuster 122. The rinse liquid supplied from the rinse liquid supply source 123 is, for example, DIW or the like. Further, the hydrogen dissolution unit 121 is connected to a hydrogen supply source 125 via a flow rate adjuster 124.

[0049] The hydrogen dissolution section 121 dissolves hydrogen supplied from the hydrogen supply source 125 in the rinse liquid supplied from the rinse liquid supply source 123 to generate a rinse liquid in which hydrogen is dissolved. The dissolution of hydrogen in the rinse liquid is realized, for example, using hollow fibers or the like. The rinse liquid in which hydrogen is dissolved in the hydrogen dissolution section 121 is discharged from the nozzle 51.

[0050] Also, the nozzle 51 is connected to the hydrogen dissolution section 131. The hydrogen dissolution section 131 is connected to the organic solvent supply source 133 via the flow regulator 132. The organic solvent supplied from the organic solvent supply source 133 is, for example, IPA (isopropyl alcohol) or the like. Also, the hydrogen dissolution section 131 is connected to the hydrogen supply source 135 via the flow regulator 134.

[0051] The hydrogen dissolution section 131 dissolves hydrogen supplied from the hydrogen supply source 135 in the organic solvent supplied from the organic solvent supply source 133 to generate an organic solvent in which hydrogen is dissolved. The dissolution of hydrogen in the organic solvent is realized, for example, using hollow fibers or the like. The organic solvent in which hydrogen is dissolved in the hydrogen dissolution section 131 is discharged from the nozzle 51.

[0052] Also, the nozzle 51 is connected to the hydrogen dissolution section 141. The hydrogen dissolution section 141 is connected to the film-forming treatment liquid supply source 143 via the flow regulator 142 and the heating section 146. The film-forming treatment liquid supplied from the film-forming treatment liquid supply source 143 is, for example, a solution in which a film-forming material is diluted with an organic solvent such as IPA. As the film-forming material, for example, thiol, disulfide, thiocyanate, etc. are used. The film-forming treatment liquid supplied from the film-forming treatment liquid supply source 143 is supplied to the hydrogen dissolution section 141 in a state heated to a desired temperature, specifically, a temperature of 25°C or higher, by the heating section 146. Also, the hydrogen dissolution section 141 is connected to the hydrogen supply source 135 via the flow regulator 144.

[0053] The hydrogen dissolution unit 141 dissolves hydrogen supplied from the hydrogen supply source 145 in the film-forming treatment liquid supplied from the film-forming treatment liquid supply source 143 to generate a film-forming treatment liquid in which hydrogen is dissolved. The dissolution of hydrogen in the film-forming treatment liquid is realized using, for example, hollow fibers or the like. The film-forming treatment liquid in which hydrogen is dissolved in the hydrogen dissolution unit 141 is discharged from the nozzle 51.

[0054] Oxygen may be dissolved in the oxide film removal liquid, the rinse liquid, the organic solvent, and the film-forming treatment liquid. Here, from the viewpoint of suppressing the oxidation of the surface of the metal film M1, not only the oxygen concentration in the oxide film removal liquid but also the oxygen concentrations in the rinse liquid, the organic solvent, and the film-forming treatment liquid are preferably low. Therefore, in the substrate processing apparatus 14 according to the embodiment, an oxide film removal liquid, a rinse liquid, an organic solvent, and a film-forming treatment liquid in which hydrogen is dissolved are used. By using an oxide film removal liquid, a rinse liquid, an organic solvent, and a film-forming treatment liquid in which hydrogen is dissolved, the oxygen dissolved in the oxide film removal liquid, the rinse liquid, the organic solvent, and the film-forming treatment liquid reacts with hydrogen and changes to water, so that the oxidation of the surface of the metal film M1 can be suppressed. Thereby, in the formation of the protective film using the film-forming material, the protective film can be suitably formed on the surface of the metal film M1.

[0055] Note that the flow rate regulators 112, 114, 122, 124, 132, 134, 142, and 144 include on-off valves, flow control valves, flow meters, and the like.

[0056] Here, an example in which the substrate processing apparatus 14 includes a single nozzle 51 is shown, but the substrate processing apparatus 14 may include a plurality of nozzles and may be configured to discharge an oxide film removal liquid, a film-forming treatment liquid, or the like from separate nozzles.

[0057] The lower supply unit 60 includes an underplate 61 that is inserted into the main body 31 of the substrate holding mechanism 30 and disposed below the wafer W, and a drive unit 62 that raises and lowers the underplate 61.

[0058] The underplate 61 is a member formed to cover the back surface of the wafer W. Inside the underplate 61, a flow path 611 penetrating the underplate 61 vertically is formed. A heating fluid supply source 602 is connected to such a flow path 611 via a flow rate regulator 601. The heating fluid supplied from the heating fluid supply source 602 is used to heat the wafer W. As the heating fluid, an inert gas such as nitrogen is used, for example. Note that the heating fluid may be a heated liquid.

[0059] The lower supply unit 60 supplies the heating fluid supplied from the heating fluid supply source 602 to the back surface of the wafer W by discharging it from the flow path 611 of the underplate 61. Thereby, the wafer W can be heated to a desired temperature, specifically, a temperature of 25°C or higher.

[0060] The recovery cup 70 is arranged to surround the substrate holding mechanism 30 and collects the processing liquid scattered from the wafer W by the rotation of the main body 31 and the holding member 32 of the substrate holding mechanism 30. A drain port 71 is formed at the bottom of the recovery cup 70, and the processing liquid collected by the recovery cup 70 is discharged to the outside of the substrate processing apparatus 14 from such a drain port 71. Further, an exhaust port 72 for discharging the downflow gas supplied from the FFU 21 to the outside of the substrate processing apparatus 14 is formed at the bottom of the recovery cup 70.

[0061] <Specific Operations of the Substrate Processing Apparatus> Next, the specific operations of the substrate processing apparatus 14 will be described with reference to FIGS. 5 and 6. FIG. 5 is a flowchart showing the procedure of the process executed by the substrate processing system 1 according to the embodiment. FIG. 6 is a diagram showing an example of the wafer W after the film formation process. Each apparatus included in the substrate processing system 1 executes each process procedure shown in FIG. 5 according to the control of the control unit 15.

[0062] As shown in FIG. 5, in the substrate processing apparatus 14, first, a loading process is performed (step S101). In the loading process, the wafer W carried into the chamber 20 by the substrate transfer device 301 (see FIG. 1) is held by the substrate holding mechanism 30. The wafer W is held by the holding member 32 with the pattern formation surface shown in FIG. 2 facing upward. Then, the main body 31 and the holding member 32 are rotated by the drive unit 33. As a result, the wafer W rotates together with the holding member 32.

[0063] Subsequently, in the substrate processing apparatus 14, a oxide film removing process is performed (step S102). In the oxide film removing process, first, the top plate 41 of the deoxygenation atmosphere maintaining unit 40 is disposed at the processing position. Also, the nozzle 51 of the processing fluid supply unit 50 is inserted into the opening 411 of the top plate 41. Then, by opening the valves of the flow rate regulators 112 and 114 for a predetermined time, an oxide film removing liquid in which hydrogen is dissolved is supplied from the nozzle 51 to the surface of the wafer W. The oxide film removing liquid supplied to the surface of the wafer W spreads over the entire surface of the wafer W due to the rotation of the wafer W. As a result, the space between the wafer W and the top plate 41 is filled with the oxide film removing liquid. By supplying the oxide film removing liquid to the surface of the wafer W, the oxide film formed on the surface of the metal film M1 can be removed. Since hydrogen is dissolved in the oxide film removing liquid supplied to the surface of the wafer W, the oxygen dissolved in the oxide film removing liquid reacts with hydrogen and changes to water, suppressing the oxidation of the surface of the metal film M1. As a result, in the subsequent film forming process, a film can be suitably formed on the surface of the metal film M1.

[0064] Subsequently, in the substrate processing apparatus 14, a rinsing process is performed (step S103). In the rinsing process, the valves of the flow rate regulators 122 and 124 are opened for a predetermined time, so that a rinsing liquid in which hydrogen is dissolved is supplied from the nozzle 51 to the surface of the wafer W. The rinsing liquid supplied to the surface of the wafer W spreads over the entire surface of the wafer W due to the rotation of the wafer W. As a result, the oxide film removing liquid on the wafer W is removed from the wafer W by the rinsing liquid, and the space between the wafer W and the top plate 41 is filled with the rinsing liquid. Since hydrogen is dissolved in the rinsing liquid that fills the space between the wafer W and the top plate 41, the oxygen dissolved in the rinsing liquid reacts with hydrogen to change into water, and the oxidation of the surface of the metal film M1 is suppressed. Thereby, in the subsequent film forming process, a film can be suitably formed on the surface of the metal film M1.

[0065] Subsequently, in the substrate processing apparatus 14, a substitution process is performed (step S104). In the substitution process, the valves of the flow rate regulators 132 and 134 are opened for a predetermined time, so that an organic solvent in which hydrogen is dissolved is supplied from the nozzle 51 to the surface of the wafer W. The organic solvent supplied to the surface of the wafer W spreads over the entire surface of the wafer W due to the rotation of the wafer W. As a result, the rinsing liquid on the wafer W is replaced with an organic solvent such as IPA having high affinity with the film forming treatment liquid, and the space between the wafer W and the top plate 41 is filled with the organic solvent. Since hydrogen is dissolved in the organic solvent that fills the space between the wafer W and the top plate 41, the oxygen dissolved in the rinsing liquid reacts with hydrogen to change into water, and the oxidation of the surface of the metal film M1 is suppressed. Thereby, in the subsequent film forming process, a film can be suitably formed on the surface of the metal film M1.

[0066] Subsequently, in the substrate processing apparatus 14, a film formation process is performed (step S105). In the film formation process, the valves of the flow rate regulators 142 and 144 are opened for a predetermined time, so that a film formation processing liquid in which hydrogen is dissolved and heated is supplied from the nozzle 51 to the surface of the wafer W. The film formation processing liquid supplied to the surface of the wafer W spreads over the entire surface of the wafer W due to the rotation of the wafer W. As a result, the space between the wafer W and the top plate 41 is filled with the film formation processing liquid. Then, by supplying the film formation processing liquid to the surface of the wafer W, a protective film M3 is selectively formed on the surface of the metal film M1 (see FIG. 6). Thereafter, the top plate 41 of the deoxygenated atmosphere maintaining unit 40 moves from above the wafer W to a retracted position where it is retracted.

[0067] As described above, the substrate processing apparatus 14 according to the embodiment maintains the atmosphere in contact with the surface of the wafer W as a deoxygenated atmosphere by filling the space between the wafer W and the top plate 41 with the oxide film removal liquid, the rinse liquid, or the film formation processing liquid until the film formation process is completed. Thereby, since the formation of the oxide film on the surface of the metal film M1 is suppressed, the protective film M3 can be suitably formed on the surface of the metal film M1 in the film formation process.

[0068] Further, since the film formation processing liquid is supplied to the wafer W in a state heated by the heating unit 146, the protective film M3 can be suitably formed on the surface of the metal film M1 in a short time as compared with the case where the film formation processing liquid is not heated. In addition, the substrate processing apparatus 14 can heat the film formation processing liquid on the wafer W using the heating unit 412 provided on the top plate 41. Further, the substrate processing apparatus 14 can also heat the wafer W by supplying a heating fluid from the lower supply unit 60. Thereby, since the processing temperature during the film formation process can be maintained at a desired temperature, the formation of the protective film M3 on the metal film M1 can be performed more suitably. Here, an example in which the top plate 41 includes the heating unit 412 has been described, but it is sufficient that the processing temperature during the film formation process can be adjusted, and a configuration including a temperature adjustment unit having a cooling function in addition to the heating function may be employed.

[0069] Further, after the film formation process, by moving the top plate 41 of the deoxygenated atmosphere maintaining unit 40 to a retracted position retracted from above the wafer W, it is possible to suppress the liquid remaining on the lower surface of the top plate 41 from falling and adhering to the surface of the wafer W. Note that the substrate processing apparatus 14 is not limited to this, and may have a configuration including, for example, a tray for receiving the liquid falling from the top plate 41 and a drive unit for moving the tray. In this case, after raising the top plate 41, the tray is moved between the top plate 41 and the wafer W. Thereby, it is possible to suppress the liquid falling from the top plate 41 from adhering to the surface of the wafer W.

[0070] In the film formation process, the substrate processing apparatus 14 may discharge the film formation processing liquid staying in the space between the top plate 41 and the surface of the wafer W by continuously supplying the film formation processing liquid from the processing fluid supply unit 50. If the liquid stays in the space between the top plate 41 and the surface of the wafer W for a long time, oxygen may dissolve in the staying liquid, and the dissolved oxygen may reach the surface of the metal film M1 by diffusion or the like and oxidize the surface of the metal film M1. On the other hand, by continuously supplying the film formation processing liquid and discharging the liquid staying on the surface of the wafer W, it is possible to suppress oxygen from reaching the surface of the metal film M1.

[0071] In the film formation process, the substrate processing apparatus 14 may supply a rinsing liquid heated to the back surface of the wafer W from the lower supply unit 60. Thereby, it is possible to suppress the film formation processing liquid from flowing around to the back surface of the wafer W.

[0072] Subsequently, in the substrate processing apparatus 14, a rinsing process is performed (step S106). In the rinsing process, by opening the valves of the flow regulators 122 and 124 for a predetermined time, a rinsing liquid in which hydrogen is dissolved is supplied from the nozzle 51 to the surface of the wafer W. The rinsing liquid supplied to the surface of the wafer W spreads over the entire surface of the wafer W due to the rotation of the wafer W. Thereby, the film-forming treatment liquid on the wafer W is removed from the wafer W by the rinsing liquid. In addition, in the rinsing process of step S106, only the valve of the flow regulator 122 may be opened to supply a rinsing liquid in which hydrogen is not dissolved from the nozzle 51 to the surface of the wafer W.

[0073] Subsequently, in the substrate processing apparatus 14, a drying process is performed (step S107). In the drying process, for example, by increasing the rotation speed of the wafer W, the rinsing liquid remaining on the surface of the wafer W is shaken off to dry the wafer W.

[0074] Subsequently, in the substrate processing apparatus 14, an unloading process is performed (step S108). In the unloading process, the wafer W is taken out from the chamber 20 of the substrate processing apparatus 14 by the substrate transfer device 301 (see FIG. 1). Thereafter, the wafer W is accommodated in the carrier C placed on the carrier placement unit 11 via the delivery unit 202 and the substrate transfer device 201. When the unloading process is completed, the process for one wafer W is completed.

[0075] <Modification Example> In the above-described embodiment, an oxygen-free atmosphere is locally formed using the oxygen-free atmosphere maintaining unit 40. However, the present invention is not limited to this, and the substrate processing apparatus may form an oxygen-free atmosphere throughout the chamber 20, for example, by supplying an inert gas such as nitrogen from the FFU 21.

[0076] In the above-described embodiment, an example of the oxide film removal liquid, dilute hydrochloric acid, was described. However, the oxide film removal liquid is not limited thereto. For example, the oxide film removal liquid may be a solution in which hydrofluoric acid is diluted with an organic solvent such as IPA. The solution in which hydrofluoric acid is diluted with an organic solvent such as IPA may not contain DIW. In this case, an organic solvent is preferably used as the rinse liquid for removing the oxide film removal liquid on the wafer W. When an organic solvent is used as the rinse liquid, the substitution treatment (see step S104 in FIG. 5) is omitted.

[0077] As described above, the substrate processing method according to the embodiment includes a step of removing an oxide film (for example, an oxide film removal process) and a step of forming a protective film (for example, a film forming process). In the step of removing the oxide film, an oxide film removal liquid in which hydrogen is dissolved is supplied to the surface of a substrate (for example, a wafer W) on which a metal film (for example, a metal film M1) and other films (for example, an insulating film M2) are exposed on the surface, thereby removing the oxide film from the surface of the metal film. In the step of forming the protective film, after the step of removing the oxide film, a protective film (for example, a protective film M3) is formed on the surface of the metal film using a film forming material that selectively adsorbs to the metal film among the metal film and other films.

[0078] Therefore, according to the substrate processing method according to the embodiment, a protective film can be suitably formed on the surface of the metal film.

[0079] The metal material for forming the metal film may contain at least one of gold, silver, copper, iron, cobalt, nickel, zinc, rhodium, ruthenium, palladium, platinum, osmium, and iridium. The film forming material may contain sulfur atoms. Thereby, a protective film can be suitably formed on the surface of a metal film containing at least one of gold, silver, copper, iron, cobalt, nickel, zinc, rhodium, ruthenium, palladium, platinum, osmium, and iridium.

[0080] The concentration of dissolved hydrogen in the oxide film removal liquid is 1.2 ppm or more. Thereby, the oxidation of the surface of the metal film can be stably suppressed.

[0081] The substrate processing method according to the embodiment may further include a step (for example, a rinsing process) of supplying a rinsing liquid in which hydrogen is dissolved to the surface of the substrate after the step of removing the oxide film and before the step of forming the protective film. Thereby, a protective film can be suitably formed on the surface of the metal film in the step of forming the protective film.

[0082] The substrate processing method according to the embodiment may further include a step (for example, a substitution process) of substituting the rinsing liquid on the surface of the substrate with an organic solvent in which hydrogen is dissolved after the step of supplying the rinsing liquid and before the step of forming the protective film. Thereby, a protective film can be suitably formed on the surface of the metal film in the step of forming the protective film.

[0083] The step of forming the protective film may be a film-forming treatment liquid in which a film-forming material is diluted with an organic solvent, and a protective film may be formed on the surface of the metal film by supplying the film-forming treatment liquid in which hydrogen is dissolved to the surface of the substrate. Thereby, a protective film can be suitably formed on the surface of the metal film in the step of forming the protective film.

[0084] The substrate processing method according to the embodiment may further include a step of maintaining the atmosphere in contact with the surface of the metal film as a deoxidized atmosphere. The step of removing the oxide film and the step of forming the protective film may be performed while being maintained in a deoxidized atmosphere. Thereby, since the formation of the oxide film on the surface of the metal material is suppressed, it is possible to suppress the formation of the protective film on the metal film from being inhibited by the oxide film in the step of forming the protective film.

[0085] In addition, the substrate processing apparatus according to the embodiment (for example, the substrate processing apparatus 14) includes an oxide film removing unit (for example, the processing fluid supply unit 50) and a protective film forming unit (for example, the processing fluid supply unit 50). The oxide film removing unit supplies an oxide film removing solution in which hydrogen is dissolved to the surface of a substrate (for example, a wafer W) on which a metal film (for example, the metal film M1) and other films (for example, the insulating film M2) are exposed on the surface, thereby removing the oxide film from the surface of the metal film. The protective film forming unit forms a protective film (for example, the protective film M3) on the surface of the metal film using a film forming material that selectively adsorbs to the metal film among the metal film and other films after the removal of the oxide film.

[0086] Therefore, according to the substrate processing apparatus according to the embodiment, a protective film can be suitably formed on the surface of the metal film.

[0087] The embodiments disclosed this time should be considered as 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

[0088] 1 Substrate processing system 14 Substrate processing apparatus 15 Control unit 20 Chamber 30 Substrate holding mechanism 40 Deoxygenated atmosphere maintaining unit 50 Processing fluid supply unit 51 Nozzle M1 Metal film M2 Insulating film M3 Protective film W Wafer

Claims

1. A step of removing an oxide film from the surface of the metal film by supplying an oxide film removing solution in which hydrogen is dissolved to the surface of a substrate on which a metal film and other films are exposed on the surface; A step of forming a protective film on the surface of the metal film using a film forming material that selectively adsorbs to the metal film among the metal film and the other films after the step of removing the oxide film; A substrate processing method comprising:

2. The metal material for forming the metal film is at least one of gold, silver, copper, iron, cobalt, nickel, zinc, rhodium, ruthenium, palladium, platinum, osmium and iridium; The film forming material is The substrate processing method according to claim 1, which contains sulfur atoms.

3. The concentration of dissolved hydrogen in the oxide film removing solution is 1.2 ppm or more. The substrate processing method according to claim 1.

4. A step of supplying a rinsing solution in which hydrogen is dissolved to the surface of the substrate after the step of removing the oxide film and before the step of forming the protective film; The substrate processing method according to claim 1, further comprising:

5. A step of replacing the rinsing solution on the surface of the substrate with an organic solvent in which hydrogen is dissolved after the step of supplying the rinsing solution and before the step of forming the protective film; The substrate processing method according to claim 4, further comprising:

6. The step of forming the protective film is A film forming treatment solution in which the film forming material is diluted with an organic solvent, and the protective film is formed on the surface of the metal film by supplying the film forming treatment solution in which hydrogen is dissolved to the surface of the substrate. The substrate processing method according to claim 1.

7. A step of maintaining the atmosphere in contact with the surface of the metal film as a deoxidized atmosphere; further comprising, The step of removing the oxide film and the step of forming the protective film are performed in a state maintained in the deoxidized atmosphere. The substrate processing method according to claim 1.

8. An oxide film removing unit that removes an oxide film from the surface of the metal film by supplying an oxide film removing solution in which hydrogen is dissolved to the surface of a substrate on which a metal film and other films are exposed on the surface; A protective film forming unit that forms a protective film on the surface of the metal film using a film forming material that selectively adsorbs to the metal film among the metal film and the other films after the removal of the oxide film; A substrate processing apparatus comprising:

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