Plating method and plating apparatus

Abstract

A plating method according to one embodiment of the present disclosure comprises: a step for supplying an ionic liquid into a processing chamber which is configured such that depressurization is possible, and in which a metal target material is disposed; a step for producing a plating solution by generating plasma while introducing a gas into the processing chamber, causing particles of the target material to be released by the sputtering action of the plasma, and dispersing the particles in the ionic liquid; and a step for forming a metal film on the surface of a substrate by immersing the substrate in the plating solution.

Description

Plating method and plating apparatus

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

[0002] A technique for forming copper wiring by the damascene method is known (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2002-118109

[0004] The present disclosure provides a technique capable of forming a metal film containing a base metal on the surface of a substrate.

[0005] A plating method according to one aspect of the present disclosure includes the steps of: supplying an ionic liquid into a process vessel configured to be depressurized and in which a metal target material is placed; generating plasma while introducing a gas into the process vessel, causing the sputtering action of the plasma to release particles of the target material, and dispersing the particles in the ionic liquid to produce a plating solution; and immersing a substrate in the plating solution to form a metal film on the surface of the substrate.

[0006] According to the present disclosure, a metal film containing a base metal can be formed on the surface of a substrate.

[0007] FIG. 1 is a flowchart showing a plating method according to an embodiment; FIG. 2 is a cross-sectional view (1) showing the plating method according to an embodiment; FIG. 3 is a cross-sectional view (2) showing the plating method according to an embodiment; FIG. 4 is a cross-sectional view (3) showing the plating method according to an embodiment; FIG. 5 is a cross-sectional view (5) showing the plating method according to an embodiment; FIG. 6 is a schematic view showing a plating processing apparatus according to a first example of an embodiment; FIG. 7 is a schematic view showing a plating processing apparatus according to a second example of an embodiment; and FIG. 8 is a diagram showing an EDX spectrum of a metal film formed by the plating method according to an embodiment.

[0008] Hereinafter, non-limiting exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings. In all the accompanying drawings, the same or corresponding reference numerals are used to designate the same or corresponding members or components, and redundant descriptions will be omitted.

[0009] [Plating Method] A plating method according to an embodiment will be described with reference to Fig. 1 to Fig. 6. Fig. 1 is a flowchart showing the plating method according to an embodiment. Fig. 2 to Fig. 6 are cross-sectional views showing the plating method according to an embodiment. The plating method according to an embodiment includes steps S11 to S15 shown in Fig. 1.

[0010] In step S11, as shown in FIG. 2, a substrate 100 is prepared. The substrate 100 has a lower interconnection 101 and an insulating film 102. The insulating film 102 is formed on the lower interconnection 101. The insulating film 102 is, for example, an interlayer insulating film. A recess 103 is provided in the insulating film 102. The lower interconnection 101 is exposed at the bottom of the recess 103. The recess 103 includes a via hole 104 and a trench 105. The via hole 104 is provided in the lower part of the insulating film 102 in the thickness direction. The trench 105 is provided in the upper part of the insulating film 102 in the thickness direction. The lower part of the trench 105 communicates with the upper part of the via hole 104.

[0011] Step S12 is performed after step S11. In step S12, as shown in FIG. 3 , a seed layer 106 is formed on the upper surface of the insulating film 102, the inner side surface of the recess 103, and the upper surface of the lower interconnect 101 exposed at the bottom of the recess 103. The seed layer 106 is, for example, a copper film. For example, in a reduced pressure atmosphere, plasma is generated from a plasma generation gas, and particles 19p of a metal target material 19 are emitted by the sputtering action of the generated plasma, and the emitted particles 19p are deposited on the substrate 100. In this way, the seed layer 106 is formed. The metal constituting the target material 19 is, for example, copper.

[0012] Step S13 is performed after step S12. In step S13, as shown in Fig. 4, the substrate 100 is immersed in an ionic liquid 107 containing a first metal element 108. The ionic liquid 107 is, for example, Emim-Al ２ Cl ７The first metal element 108 is, for example, aluminum. For example, in a reduced pressure atmosphere, the ionic liquid 107 is supplied from the nozzle 16b into a storage container (not shown) containing the substrate 100, and the ionic liquid 107 is stored in the storage container, and the substrate 100 is immersed in the ionic liquid 107. In step S13, the ionic liquid 107 may be heated. In this case, if the ionic liquid 107 contains moisture, the moisture can be removed.

[0013] Step S14 is performed after step S13. In step S14, as shown in FIG. 5 , a second metal element 109 is added to the ionic liquid 107 to produce a plating solution 110 from the ionic liquid 107. The second metal element 109 is a metal element different from the first metal element 108. The second metal element 109 is, for example, copper. For example, in a reduced pressure atmosphere, plasma is generated from a plasma generating gas, and particles 19p of a metal target material 19 are released by the sputtering action of the generated plasma, and the released particles 19p are dispersed in the ionic liquid 107. The target material 19 contains the second metal element 109. This produces a plating solution 110 containing the first metal element 108 and the second metal element 109. When producing the plating solution 110 using the sputtering action, the second metal element 109 can be added with a higher purity than when producing the plating solution 110 by adding a precursor compound containing the second metal element 109 to the ionic liquid 107. Ionic liquid 107 can be used in a high-temperature environment (for example, 100°C or higher) compared to aqueous solutions. Therefore, the usable temperature range is expanded when adding second metal element 109 to ionic liquid 107 by sputtering. Step S14 is performed in a state where substrate 100 is immersed in a storage container in which ionic liquid 107 is stored, as shown in FIG. 5, for example. Step S14 may also be performed in a state where substrate 100 is not immersed in a storage container in which ionic liquid 107 is stored.

[0014] Step S15 is performed after step S14. In step S15, as shown in FIG. 6 , a plating film 111 containing a first metal element 108 and a second metal element 109 is formed on the seed layer 106. The plating film 111 is an example of a metal film. For example, in a reduced pressure atmosphere, the substrate 100 is immersed in the plating solution 110 produced in step S14, and the plating film 111 can be embedded inside the recess 103 by electroplating. When electroplating is used, the deposition rate of the plating film 111 can be easily controlled.

[0015] By carrying out the above steps S11 to S15, the plating film 111 can be embedded in the recesses 103 formed on the surface of the substrate 100.

[0016] As described above, according to the plating method of the embodiment, the second metal element 109 is added to the ionic liquid 107 by sputtering to produce the plating solution 110, and the substrate 100 is immersed in the plating solution 110 to form the plating film 111 on the surface of the substrate 100. In this case, the plating film 111 containing a base metal can be formed on the surface of the substrate 100. In contrast, when the plating film 111 is formed using an aqueous solution instead of the ionic liquid 107, a water decomposition reaction occurs, making it difficult to form the plating film 111.

[0017] According to the plating method of the embodiment, a plating solution 110 is produced from an ionic liquid 107 in a reduced pressure atmosphere, and a substrate 100 is immersed in the plating solution 110 to form a plating film 111 on the surface of the substrate 100. This is advantageous from the viewpoint of preventing oxidation of metal deposition such as aluminum, which is sensitive to oxygen.

[0018] In the above embodiment, steps S12 to S15 are performed in the same processing chamber, for example. In this case, the seed layer 106 and the plating film 111 can be formed in one processing chamber, thereby improving productivity.

[0019] [Plating Processing Apparatus] (First Example) A plating processing apparatus 1 according to a first example of the embodiment will be described with reference to Fig. 7. Fig. 7 is a schematic diagram showing the plating processing apparatus 1 according to the first example of the embodiment.

[0020] 7 , the plating processing apparatus 1 includes a processing vessel 11, an exhaust device 12, a support table 13, a heater 14, a storage vessel 15, an ionic liquid supply unit 16, a gas introduction unit 17, a backing plate 18, a target material 19, a sputtering power supply 20, an electrodeposition unit 21, a vacuum gauge 22, a spectrophotometer 23, and a control unit 24. The heater 14, the storage vessel 15, the ionic liquid supply unit 16, the gas introduction unit 17, the backing plate 18, the target material 19, the sputtering power supply 20, and the spectrophotometer 23 constitute a plating solution production mechanism.

[0021] The processing vessel 11 is a vacuum chamber that can be depressurized. A loading / unloading port 11a is provided on a sidewall of the processing vessel 11. The loading / unloading port 11a is an opening through which the substrate 100 passes when the substrate 100 is loaded into the processing vessel 11 or unloaded from the processing vessel 11. The loading / unloading port 11a is opened and closed by a gate valve (not shown).

[0022] The exhaust device 12 includes an exhaust pipe 12 a and a vacuum pump 12 b. The exhaust pipe 12 a is connected to the processing chamber 11. The vacuum pump 12 b is provided midway along the exhaust pipe 12 a. The exhaust device 12 evacuates the processing chamber 11 via the exhaust pipe 12 a and reduces the pressure therein by operating the vacuum pump 12 b.

[0023] The holding table 13 is provided in the processing vessel 11. The holding table 13 is fixed to, for example, the bottom of the processing vessel 11. The holding table 13 holds a heater 14 and a storage vessel 15.

[0024] The heater 14 is provided on the holder 13. The heater 14 heats the ionic liquid 107 and the plating solution 110 stored in the storage container 15.

[0025] The storage container 15 is provided in the processing container 11. The storage container 15 is provided, for example, on the heater 14. The storage container 15 stores the ionic liquid 107 and the plating solution 110. The storage container 15 is configured so that the substrate 100 can be placed therein.

[0026] The ionic liquid supply unit 16 includes a supply port 16a and a nozzle 16b. One end of the supply port 16a is connected to a supply source (not shown) of the ionic liquid 107, and the other end is connected to the sidewall of the processing vessel 11. The nozzle 16b has a base end connected to the supply port 16a and a tip end located above the storage vessel 15. The ionic liquid supply unit 16 introduces the ionic liquid 107 from the supply source into the nozzle 16b via the supply port 16a, and supplies the ionic liquid 107 from the tip of the nozzle 16b toward the storage vessel 15.

[0027] The gas inlet 17 is connected to the sidewall of the processing chamber 11. The gas inlet 17 introduces a plasma generating gas into the processing chamber 11. The plasma generating gas is, for example, argon gas.

[0028] The backing plate 18 is fixed to the ceiling of the processing vessel 11. The backing plate 18 holds a target material 19.

[0029] The target material 19 is fixed to the backing plate 18. The target material 19 is disposed, for example, facing the storage container 15. The target material 19 is made of metal. The metal constituting the target material 19 is, for example, copper.

[0030] The sputtering power supply 20 supplies power between the holder 13 and the backing plate 18. This generates plasma from the plasma generation gas introduced into the processing chamber 11 from the gas inlet 17. The sputtering power supply 20 is, for example, an RF (Radio Frequency) power supply. The sputtering power supply 20 may also be a DC (Direct Current) power supply. The holder 13, the backing plate 18, and the sputtering power supply 20 constitute a plasma generation unit.

[0031] The electrodeposition unit 21 includes an electrodeposition power supply 21a, a working electrode 21b, a counter electrode (not shown), and a reference electrode (not shown). The working electrode 21b is electrically connected to the seed layer 106 of the substrate 100. The electrodeposition unit 21 supplies power between the working electrode 21b and the counter electrode. As a result, a plating film 111 is formed on the seed layer 106.

[0032] The vacuum gauge 22 detects the pressure inside the processing vessel 11. The vacuum gauge 22 is provided on the sidewall of the processing vessel 11, for example.

[0033] The spectrophotometer 23 includes a light source 23a and a detector 23b. The light source 23a and the detector 23b are arranged opposite each other with the storage container 15 therebetween. The light source 23a and the detector 23b are provided, for example, on the side wall of the processing container 11. At least one of the light source 23a and the detector 23b may include a spectroscope. The spectrophotometer 23 detects the state of the ionic liquid 107 by passing light from the light source 23a through the ionic liquid 107 stored in the storage container 15 and detecting the light that has passed through the ionic liquid 107 with the detector 23b. The spectrophotometer 23 detects the state of the ionic liquid 107 by, for example, colorimetry. The state of the ionic liquid 107 is, for example, the concentration of impurities contained in the ionic liquid 107. The spectrophotometer 23 is an example of a detection unit.

[0034] The control unit 24 is, for example, a computer. The control unit 24 includes an arithmetic unit 24a and a memory unit 24b. The memory unit 24b stores programs that control various processes executed in the plating processing device 1. The arithmetic unit 24a controls the operation of the plating processing device 1 by reading and executing the programs stored in the memory unit 24b. The programs may be recorded on a computer-readable storage medium and installed from the storage medium into the memory unit 24b of the control unit 24. Examples of computer-readable storage media include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnetic optical disk (MO), and a memory card.

[0035] 7, an example of the operation of the plating processing apparatus 1 will be described. The following describes an example in which the plating processing apparatus 1 successively forms a seed layer 106 and a plating film 111 in this order on the substrate 100 under the control of the control unit 24.

[0036] First, in a state where the ionic liquid 107 is not stored in the storage container 15 , a transfer device (not shown) carries the substrate 100 into the processing container 11 and places the substrate 100 in the storage container 15 .

[0037] Next, the exhaust device 12 reduces the pressure inside the processing chamber 11. Subsequently, the gas inlet 17 introduces a plasma generating gas into the processing chamber 11, and the sputtering power supply 20 supplies power between the support table 13 and the backing plate 18. This generates plasma from the plasma generating gas inside the processing chamber 11. In the processing chamber 11, particles 19p of the target material 19 are emitted by the sputtering action of the plasma, and the emitted particles 19p are deposited on the substrate 100. As a result, a seed layer 106 is formed on the upper surface of the insulating film 102 on the substrate 100, the inner surface of the recess 103, and the upper surface of the lower interconnect 101 exposed at the bottom of the recess 103. After a predetermined time has elapsed, the supply of power from the sputtering power supply 20 is stopped, and the introduction of the plasma generating gas from the gas inlet 17 is stopped.

[0038] Next, the ionic liquid supply unit 16 supplies the ionic liquid 107 into the storage container 15 on which the substrate 100 is placed. As a result, the substrate 100 is immersed in the ionic liquid 107.

[0039] Next, the gas inlet 17 introduces a plasma generating gas into the processing vessel 11, and the sputtering power supply 20 supplies power between the holding table 13 and the backing plate 18. As a result, plasma is generated from the plasma generating gas in the processing vessel 11. The sputtering action of the generated plasma releases particles 19p from the target material 19, and the released particles 19p disperse into the ionic liquid 107. The target material 19 contains a second metal element 109. In this manner, the second metal element 109 is added to the ionic liquid 107 stored in the storage vessel 15, and a plating solution 110 containing the first metal element 108 and the second metal element 109 is produced. After a predetermined time has elapsed, the supply of power from the sputtering power supply 20 is stopped, and the supply of the plasma generating gas from the gas inlet 17 is stopped.

[0040] Next, the electrodeposition power supply 21 a supplies power between the working electrode 21 b and the counter electrode 21 b, thereby forming a plating film 111 containing the first metal element 108 and the second metal element 109 on the seed layer 106. After a predetermined time has elapsed, the supply of power from the electrodeposition power supply 21 a is stopped.

[0041] Next, the transfer device transfers the substrate 100 placed in the storage container 15 to the outside of the processing container 11. As a result, the seed layer 106 and the plating film 111 can be formed successively in this order on the substrate 100. In this case, the plating film 111 can be formed on the seed layer 106 without exposing the seed layer 106 to the atmosphere. This prevents oxidation of the seed layer 106.

[0042] In the embodiment, the case where the substrate 100 is placed in the storage container 15 before the ionic liquid 107 is supplied into the storage container 15 and the seed layer 106 is formed has been described, but the present invention is not limited to this. For example, the ionic liquid 107 may be supplied into the storage container 15 before the seed layer 106 is formed on the substrate 100. In this case, the seed layer 106 may be formed on the substrate 100 in a state where the substrate 100 is moved to a position where the substrate 100 is not immersed in the ionic liquid 107, for example, to a position above the storage container 15 by a lifting pin (not shown).

[0043] Second Example A plating processing apparatus 1A according to a second example of the embodiment will be described with reference to Fig. 8. Fig. 8 is a schematic diagram showing a plating processing apparatus 1A according to the second example of the embodiment.

[0044] 8, plating processing apparatus 1A differs from plating processing apparatus 1 in that plating film 111 is formed in a container that is provided separately from the container that produces plating solution 110. Hereinafter, the same components as those in plating processing apparatus 1 will be assigned the same reference numerals and descriptions thereof will be omitted.

[0045] As shown in FIG. 8, the plating processing apparatus 1A includes a plating solution producing unit 10, a plating film forming unit 30, a transporting unit 40, and a control unit 90.

[0046] The plating solution production unit 10 includes a processing vessel 11, an exhaust device 12, a holding table 13, a heater 14, a storage vessel 15, an ionic liquid supply unit 16, a gas introduction unit 17, a backing plate 18, a target material 19, a sputtering power supply 20, a vacuum gauge 22, and a spectrophotometer 23. The heater 14, the storage vessel 15, the ionic liquid supply unit 16, the gas introduction unit 17, the backing plate 18, the target material 19, the sputtering power supply 20, and the spectrophotometer 23 constitute a plating solution production mechanism.

[0047] The plating film forming section 30 includes a processing vessel 31 , a holding table 32 , a storage vessel 33 , and an electrodeposition section 34 .

[0048] The processing vessel 31 is provided separately from the processing vessel 11. A loading / unloading port 31a is provided on the sidewall of the processing vessel 31. The loading / unloading port 31a is an opening through which the substrate 100 passes when the substrate 100 is loaded into the processing vessel 31 or unloaded from the processing vessel 31. The loading / unloading port 31a is opened and closed by a gate valve (not shown).

[0049] The holding table 32 is provided in the processing vessel 31. The holding table 32 is fixed to, for example, the bottom of the processing vessel 31. The holding table 32 holds the storage vessel 33.

[0050] The storage container 33 is provided outside the processing container 11. The storage container 33 is provided inside the processing container 31. The storage container 33 is provided, for example, on the holder 32. The storage container 33 stores the plating solution 110. The storage container 33 includes a first storage portion 33a, a second storage portion 33b, and a liquid junction 33c. The first storage portion 33a is configured so that the substrate 100 can be placed therein. The interiors of the first storage portion 33a and the second storage portion 33b are in communication with each other via the liquid junction 33c.

[0051] The electrodeposition unit 34 includes an electrodeposition power supply 34a, a working electrode 34b, a counter electrode 34c, a reference electrode 34d, and a voltmeter 34e. The working electrode 34b is electrically connected to the seed layer 106 of the substrate 100. The counter electrode 34c is inserted into the plating solution 110 stored in the second reservoir 33b. The reference electrode 34d is inserted into the plating solution 110 stored in the first reservoir 33a. The voltmeter 34e measures the potential of the working electrode 34b relative to the reference electrode 34d. The electrodeposition unit 34 supplies power between the working electrode 34b and the counter electrode 34c. As a result, a plating film 111 is formed on the seed layer 106.

[0052] The transport unit 40 has a connection pipe 41 and an on-off valve 42. The connection pipe 41 connects the storage container 15 and the first storage unit 33a. The connection pipe 41 communicates the interior of the storage container 15 with the interior of the first storage unit 33a. The on-off valve 42 is provided midway along the connection pipe 41. When the on-off valve 42 is opened, the plating solution 110 stored in the storage container 15 is transported to the first storage unit 33a.

[0053] The control unit 90 is, for example, a computer. The control unit 90 includes an arithmetic unit 90a and a memory unit 90b. The memory unit 90b stores programs that control various processes executed in the plating processing device 1A. The arithmetic unit 90a controls the operation of the plating processing device 1A by reading and executing the programs stored in the memory unit 90b. The programs may be recorded on a computer-readable storage medium and installed from the storage medium into the memory unit 90b of the control unit 90. Examples of computer-readable storage media include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnetic optical disk (MO), and a memory card.

[0054] An example of the operation of the plating processing apparatus 1A will be described with reference to Fig. 8. The following describes an example in which a plating film 111 is formed on a substrate 100 in the plating processing apparatus 1A under the control of the control unit 90. It is assumed that a seed layer 106 has been formed on the substrate 100 in advance.

[0055] First, the ionic liquid supply unit 16 supplies the ionic liquid 107 into the storage container 15 .

[0056] Next, the gas inlet 17 introduces a plasma generating gas into the processing vessel 11, and the sputtering power supply 20 supplies power between the holding table 13 and the backing plate 18. As a result, plasma is generated from the plasma generating gas in the processing vessel 11. The sputtering action of the generated plasma releases particles 19p from the target material 19, and the released particles 19p disperse into the ionic liquid 107. The target material 19 contains a second metal element 109. In this manner, the second metal element 109 is added to the ionic liquid 107 stored in the storage vessel 15, and a plating solution 110 containing the first metal element 108 and the second metal element 109 is produced. After a predetermined time has elapsed, the supply of power from the sputtering power supply 20 is stopped, and the supply of the plasma generating gas from the gas inlet 17 is stopped.

[0057] Next, the on-off valve 42 is opened to transport the plating solution 110 stored in the storage container 15 to the first storage section 33a. When a predetermined amount of plating solution 110 is stored in the first storage section 33a, the on-off valve 42 is closed.

[0058] Next, with plating solution 110 stored in first reservoir 33a, a transfer device (not shown) carries substrate 100 into processing vessel 31 and places it in first reservoir 33a.

[0059] Next, the electrodeposition power supply 34a supplies power between the working electrode 34b and the counter electrode 34c. As a result, a plating film 111 containing the first metal element 108 and the second metal element 109 is formed on the seed layer 106. After a predetermined time has elapsed, the supply of power from the electrodeposition power supply 34a is stopped.

[0060] Next, the transfer device transfers the substrate 100 placed in the first reservoir 33a to the outside of the processing vessel 31. In this manner, the plating film 111 can be formed on the substrate 100.

[0061] In the examples, first, a metal film was formed on a substrate 100 by the plating method according to the embodiment. ２ Cl７ A copper target material was used as the target material 19. Next, an EDX spectrum of the metal film was obtained by energy dispersive X-ray spectroscopy (EDX). Element mapping was also performed using EDX. The elements mapped were aluminum and copper.

[0062] 9 is a diagram showing an EDX spectrum of a metal film formed by the plating method according to the embodiment, in which the horizontal axis represents characteristic X-ray energy [keV] and the vertical axis represents characteristic X-ray intensity (counts) [cps / eV].

[0063] 9, it can be seen that a peak derived from aluminum (Al) and a peak derived from copper (Cu) are detected in the EDX spectrum. This result shows that an aluminum alloy film containing copper can be formed by the plating method according to the embodiment.

[0064] Furthermore, element mapping confirmed that aluminum and copper were uniformly distributed within the surface of the substrate 100 .

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

[0066] In the above embodiment, the metal constituting the target material 19 is copper, but the present disclosure is not limited to this. For example, the metal constituting the target material 19 may be a pure metal such as nickel or aluminum, or a nickel-aluminum alloy (NiAl), a copper-aluminum alloy (CuAl), or the like. ２) or an alloy such as the above. When the metal constituting the target material 19 is an alloy, the composition of the target material 19 is directly reflected, so the composition of the plating solution 110 can be controlled with high precision. Furthermore, although the above embodiment has been described as using a single target material 19, multiple metal elements may be added by co-sputtering using two or more target materials.

[0067] In the above embodiment, the seed layer 106 is described as a copper film, but the present disclosure is not limited thereto. For example, the seed layer 106 may be a nickel film, an aluminum film, a nickel-aluminum alloy film, or a copper-aluminum alloy film.

[0068] In the above embodiment, the ionic liquid 107 is Emim-Al ２ Cl ７ However, the present disclosure is not limited to this. For example, the ionic liquid 107 is preferably hydrophobic or hydrophobic. In this case, hydrogen generation is suppressed when forming the plating film 111 on the substrate 100, making it easier to deposit the plating film 111. Examples of hydrophobic ionic liquids include Emim-AlCl ４ , EMIm-Al ２ Cl ７ The types of water-repellent ionic liquids are not limited to these. Examples of hydrophobic ionic liquids include TMPA-TFSI and Bmim-PF ６ The types of hydrophobic ionic liquids are not limited to these.

[0069] In the above embodiment, the ionic liquid 107 includes the first metal element 108. However, the present disclosure is not limited to this. For example, the ionic liquid 107 does not need to include the first metal element 108. In this case, a plating solution 110 is produced that does not include the first metal element 108 but includes the second metal element 109. For example, when the ionic liquid 107 does not include the first metal element 108, the metals constituting the target material 19 may include the first metal element 108 and the second metal element 109. In this case, a plating solution 110 is produced that includes the first metal element 108 and the second metal element 109. For example, when the ionic liquid 107 is not involved in the oxidation-reduction reaction of the metal deposition during the formation of the plating film 111, the ionic liquid 107 can be reused by utilizing the non-volatilizing property of the ionic liquid 107.

[0070] In the above embodiment, the first metal element 108 is aluminum, but the present disclosure is not limited to this. For example, the first metal element 108 may be a base metal other than aluminum.

[0071] In the above embodiment, the second metal element 109 is copper, but the present disclosure is not limited to this. For example, the second metal element 109 may be nickel.

[0072] In the above embodiment, the plating film 111 is formed by electrolytic plating, but the present disclosure is not limited to this. For example, the plating film 111 may be formed by electroless plating. In this case, a power source is not required, which simplifies the device configuration. Also, the seed layer 106 is not required.

[0073] This international application claims priority based on Japanese Patent Application No. 2024-025091, filed on February 22, 2024, the entire contents of which are incorporated herein by reference.

[0074] 19 Target material 19p Particles 107 Ionic liquid 110 Plating solution 111 Plating film

Claims

1. A plating method comprising the steps of: supplying an ionic liquid into a processing vessel configured to be depressurized and in which a metallic target material is placed; generating plasma while introducing gas into the processing vessel, causing the sputtering action of the plasma to release particles from the target material, and dispersing the particles in the ionic liquid, thereby producing a plating solution; and immersing a substrate in the plating solution to form a metal film on the surface of the substrate.

2. The plating method according to claim 1, wherein the step of supplying the ionic liquid includes storing the ionic liquid in a storage container.

3. The plating method according to claim 2, further comprising the step of heating the ionic liquid stored in the storage container.

4. The plating method according to claim 1, further comprising the step of forming a seed layer on the substrate before immersing it in the plating solution.

5. The plating method according to claim 4, wherein the step of forming the seed layer is performed within the processing vessel.

6. The plating method according to claim 4, wherein the step of forming the seed layer includes generating plasma while introducing gas into the processing vessel, releasing particles of the target material by the sputtering action of the plasma, and depositing the particles on the substrate.

7. The plating method according to claim 2, wherein the step of preparing the plating solution is carried out in a state where the substrate is immersed in the storage container in which the ionic liquid is stored.

8. The plating method according to claim 2, wherein the step of preparing the plating solution is carried out without immersing the substrate in the storage container in which the ionic liquid is stored.

9. The plating method according to claim 1, wherein the step of forming the metal film includes forming the metal film by electrolytic plating.

10. The plating method according to claim 1, further comprising the step of preparing the substrate having recesses formed on its surface, and the step of forming the metal film includes embedding the metal film in the recesses.

11. The plating method according to any one of claims 1 to 10, wherein the ionic liquid is hydrophobic or hydrotropic.

12. The plating method according to any one of claims 1 to 10, wherein the ionic liquid contains a first metal element, the target material contains a second metal element different from the first metal element, and the metal film is an alloy film containing the first metal element and the second metal element.

13. The plating method according to claim 12, wherein the first metal element is a base metal.

14. The plating method according to claim 13, wherein the base metal is aluminum.

15. The plating method according to claim 14, wherein the second metal element is copper or nickel.

16. A plating processing apparatus comprising: a processing vessel capable of reducing pressure; and a plating solution production mechanism for producing a plating solution in the processing vessel, wherein the plating solution production mechanism has: a metal target material disposed in the processing vessel; an ionic liquid supply unit for supplying an ionic liquid into the processing vessel; a gas introduction unit for introducing a gas into the processing vessel; and a plasma generation unit for generating plasma from the gas.

17. The plating processing apparatus according to claim 16, wherein the plating solution production mechanism has a storage container for storing the ionic liquid, and the storage container is provided inside the processing container.

18. The plating processing apparatus according to claim 16, wherein the plating solution production mechanism has a storage container for storing the ionic liquid, and the storage container is provided outside the processing container.

19. The plating processing apparatus according to claim 17 or 18, wherein the plating solution production mechanism has a heater that heats the ionic liquid stored in the storage container.

20. The plating processing apparatus according to claim 17 or 18, wherein the plating solution production mechanism has a detection unit that detects the state of the ionic liquid stored in the storage container.

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