Substrate processing method and substrate processing apparatus

Abstract

To provide a substrate processing method and a substrate processing apparatus capable of good selective removal of a self-assembled monomolecular film on the surface of a substrate.SOLUTION: The present invention pertains to a substrate processing method for processing a substrate W with a self-assembled monomolecular film 14 on its surface, comprising: UV irradiation step S104 of irradiating the self-assembled monomolecular film 14 with UV light in an atmosphere containing oxygen atoms to reduce the water repellency of the surface of the self-assembled monomolecular film 14; and removal step S105 in which the self-assembled monomolecular film 14 after UV irradiation step is contacted with an aqueous self-assembled monomolecular film removal solution, thereby selectively removing the self-assembled monomolecular film 14.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a substrate processing method and a substrate processing apparatus capable of selectively removing a self-assembled monolayer provided on the surface of a substrate. [Background technology]

[0002] In the manufacturing of semiconductor devices, photolithography is widely used as a technique for selectively forming films on specific surface areas of a substrate. For example, after forming the underlying wiring, an insulating film is deposited, and a dual damascene structure with trenches and via holes is formed by photolithography and etching. Conductive films such as Cu are then embedded in the trenches and via holes to form the wiring.

[0003] However, with the increasing miniaturization of semiconductor devices in recent years, photolithography technology is sometimes insufficient in terms of alignment accuracy. Therefore, there is a need for alternatives to photolithography that can selectively and precisely form films on specific areas of the substrate surface.

[0004] For example, Patent Document 1 discloses a film deposition method in which a self-assembled monolayer (SAM) is formed on the surface of a substrate region where film formation is not desired, and a film is selectively formed on the substrate region where the SAM has not been formed. Furthermore, Patent Document 1 discloses that the SAM is removed using acetic acid after the selective film formation.

[0005] However, the film formation method disclosed in Patent Document 1 has the problem that selective removal of SAM by acetic acid is not sufficient. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] U.S. Patent No. 10,867,850 [Overview of the project] [Problems that the invention aims to solve]

[0007] The present invention has been made in view of the above-mentioned problems, and its objective is to provide a substrate processing method and a substrate processing apparatus that can effectively and selectively remove a self-assembled monolayer provided on the surface of a substrate. [Means for solving the problem]

[0008] The present invention provides a substrate processing method for processing a substrate having a self-assembled monolayer on its surface, in order to solve the above-mentioned problems, and is characterized by comprising: an ultraviolet irradiation step of reducing the water repellency of the surface of the self-assembled monolayer by irradiating the self-assembled monolayer with ultraviolet light in an atmosphere containing oxygen atoms; and a removal step of selectively removing the self-assembled monolayer by contacting the self-assembled monolayer after the ultraviolet irradiation step with an aqueous self-assembled monolayer removal solution.

[0009] According to the above configuration, the ultraviolet irradiation step involves irradiating with ultraviolet light in the presence of oxygen atoms. More specifically, for example, ultraviolet light is irradiated in an atmosphere containing oxygen (O2) and moisture, or while oxygen is supplied. This generates reactive oxygen species such as oxygen atoms, ozone, and OH radicals. Alternatively, ultraviolet irradiation may be carried out while supplying reactive oxygen species. This makes it possible to cleave linear or other bonding portions of the monomolecules (organic compositions) forming the self-assembled monolayer. As a result, the water repellency of the surface of the self-assembled monolayer can be reduced and modified.

[0010] In the removal process, an aqueous self-assembled monolayer removal solution is supplied to the self-assembled monolayer after UV irradiation. Because the water repellency of the surface of the self-assembled monolayer is reduced by UV irradiation, its wettability to the aqueous self-assembled monolayer removal solution is improved. As a result, the aqueous self-assembled monolayer removal solution spreads more easily on the surface of the self-assembled monolayer, thereby accelerating the removal of the self-assembled monolayer.

[0011] In other words, the substrate processing method with the above configuration can selectively remove self-assembled monolayers provided on the surface of the substrate more effectively than conventional substrate processing methods.

[0012] In the above configuration, it is preferable that the removal step is a step in which the aqueous self-assembled monolayer removal solution is brought into contact with the self-assembled monolayer after the ultraviolet irradiation step while applying a physical action to the aqueous self-assembled monolayer removal solution. By applying a physical action to the aqueous self-assembled monolayer removal solution in the removal step, this physical action can be indirectly applied to the self-assembled monolayer when the aqueous self-assembled monolayer removal solution comes into contact with the self-assembled monolayer. As a result, the peeling of the self-assembled monolayer from the substrate is promoted, and the selective removal of the self-assembled monolayer can be further improved.

[0013] In the above configuration, the removal step may be a step in which ultrasonic vibrations are applied to the aqueous self-assembled monolayer removal solution while the aqueous self-assembled monolayer removal solution is brought into contact with the self-assembled monolayer after the ultraviolet irradiation step, thereby selectively removing the self-assembled monolayer. By applying ultrasonic vibrations as a physical action to the aqueous self-assembled monolayer removal solution supplied to the surface of the self-assembled monolayer, the ultrasonic vibrations can be propagated to the self-assembled monolayer when the aqueous self-assembled monolayer removal solution comes into contact with the self-assembled monolayer. As a result, the peeling of the self-assembled monolayer from the substrate is promoted, and the selective removal of the self-assembled monolayer can be further improved.

[0014] Furthermore, in the above configuration, the removal step may be a step of selectively removing the self-assembled monolayer by bringing the droplet-shaped aqueous self-assembled monolayer removal solution, generated by contacting the aqueous self-assembled monolayer removal solution with a gas, into contact with the self-assembled monolayer. By physically contacting the aqueous self-assembled monolayer removal solution supplied to the surface of the self-assembled monolayer with a gas, the droplet-shaped aqueous self-assembled monolayer removal solution can be made to collide with and come into contact with the self-assembled monolayer. This impact promotes the delamination of the self-assembled monolayer from the substrate, thereby enabling even better selective removal of the self-assembled monolayer.

[0015] In the above configuration, the irradiation intensity of the ultraviolet light is 1 mW / cm². 2 More than 50mW / cm 2 The following range is preferable: UV irradiation intensity of 1 mW / cm² 2 By doing so, the water repellency of the self-assembled monolayer surface can be effectively reduced, and the wettability of the aqueous self-assembled monolayer removal solution to the self-assembled monolayer can be effectively maintained.

[0016] In the above configuration, it is preferable that the aqueous self-assembled monolayer removal solution contains at least an organic acid. By including an organic acid in the aqueous self-assembled monolayer removal solution, the wettability and penetration of the aqueous self-assembled monolayer removal solution into the self-assembled monolayer can be further improved. This allows for even better selective removal of the self-assembled monolayer.

[0017] In the above configuration, it is preferable that the acid dissociation constant pKa of the aqueous self-assembled monolayer removal solution is between -4 and 14. By setting the acid dissociation constant pKa of the aqueous self-assembled monolayer removal solution to -4 or higher, it is possible to prevent or reduce unnecessary etching of metal films such as Cu films or Al2O3 films on the substrate by the aqueous self-assembled monolayer removal solution.

[0018] In order to solve the above problems, the substrate processing apparatus of the present invention is a substrate processing apparatus for processing a substrate provided with a self-assembled monolayer on its surface, comprising an ultraviolet irradiation unit for irradiating ultraviolet rays, a supply unit for supplying an aqueous self-assembled monolayer removing solution to the surface of the substrate, and a control unit for controlling the ultraviolet irradiation unit and the supply unit. The control unit irradiates the self-assembled monolayer with ultraviolet rays in an atmosphere containing oxygen atoms by the ultraviolet irradiation unit, thereby reducing the water repellency of the surface of the self-assembled monolayer, and causes the supply unit to supply the aqueous self-assembled monolayer removing solution to the surface of the substrate, thereby selectively removing the self-assembled monolayer.

[0019] According to the above configuration, the control unit irradiates the self-assembled monolayer with ultraviolet rays in an atmosphere containing oxygen atoms by the ultraviolet irradiation unit. More specifically, for example, in the atmosphere containing oxygen (O2) and moisture, or ultraviolet rays are irradiated in a state where oxygen is supplied. Thereby, active oxygen species such as oxygen atoms, ozone, and OH radicals are generated. Alternatively, the control unit irradiates the ultraviolet irradiation unit with ultraviolet rays under the supply of active oxygen species. Thereby, the bonding portions such as straight chains of the single molecules (organic compositions) forming the self-assembled monolayer can be cut. As a result, the water repellency of the surface of the self-assembled monolayer can be reduced and modified.

[0020] In addition, the control unit causes the supply unit to supply the aqueous self-assembled monolayer removing solution to the self-assembled monolayer after ultraviolet irradiation. Since the surface of the self-assembled monolayer has a reduced water repellency due to the ultraviolet irradiation by the ultraviolet irradiation unit, the wettability with respect to the aqueous self-assembled monolayer removing solution is improved. As a result, the aqueous self-assembled monolayer removing solution easily spreads on the surface of the self-assembled monolayer, and the removal of the self-assembled monolayer can be promoted.

[0021] That is, with the substrate processing apparatus having the above configuration, compared with the conventional substrate processing apparatus, the selective removal of the self-assembled monolayer provided on the surface of the substrate can be favorably performed.

[0022] In the above configuration, the supply unit may include an ultrasonic application unit, and the control unit may apply ultrasonic vibration to the aqueous self-assembled monolayer removal liquid by controlling the ultrasonic application unit. As a result, the aqueous self-assembled monolayer removal liquid to which ultrasonic vibration is applied can be supplied to the self-assembled monolayer, and when the aqueous self-assembled monolayer removal liquid contacts the self-assembled monolayer, the ultrasonic vibration can be propagated to the self-assembled monolayer. Consequently, the peeling of the self-assembled monolayer from the substrate can be promoted, and the selective removal of the self-assembled monolayer can be performed even better.

[0023] In the above configuration, the supply unit may be a droplet supply unit that supplies the aqueous self-assembled monolayer removal liquid in a droplet form, and the control unit may generate the aqueous self-assembled monolayer removal liquid in a droplet form by bringing a gas into contact with the aqueous self-assembled monolayer removal liquid and eject it toward the self-assembled monolayer by controlling the droplet supply unit. By using a droplet supply unit as the supply unit, the aqueous self-assembled monolayer removal liquid in a droplet form can be collided with the self-assembled monolayer and supplied. Then, the impact promotes the peeling of the self-assembled monolayer from the substrate, and the selective removal of the self-assembled monolayer can be performed even better.

[0024] In the above configuration, the control unit may control the ultraviolet irradiation unit to make the irradiation intensity of the ultraviolet light in the range of 1 mW / cm 2 or more and 50 mW / cm 2 or less. By the control unit controlling the ultraviolet irradiation unit so that the irradiation intensity of the ultraviolet light is 1 mW / cm 2 or more, the water repellency on the surface of the self-assembled monolayer can be reduced well, and the wettability of the aqueous self-assembled monolayer removal liquid with respect to the self-assembled monolayer can be maintained well.

[0025] In the above configuration, it is preferable that the aqueous self-assembled monolayer removal solution contains at least an organic acid. By including an organic acid in the aqueous self-assembled monolayer removal solution, the wettability and penetration of the aqueous self-assembled monolayer removal solution into the self-assembled monolayer can be improved. This allows for even better selective removal of the self-assembled monolayer.

[0026] In the above configuration, it is preferable that the acid dissociation constant pKa of the aqueous self-assembled monolayer removal solution is between -4 and 14. By setting the acid dissociation constant pKa of the aqueous self-assembled monolayer removal solution to -4 or higher, it is possible to prevent or reduce unnecessary etching of metal films such as Cu films or Al2O3 films on the substrate by the aqueous self-assembled monolayer removal solution. [Effects of the Invention]

[0027] According to the present invention, it is possible to provide a substrate processing method and a substrate processing apparatus that can selectively and effectively remove a self-assembled monolayer as a protective film. [Brief explanation of the drawing]

[0028] [Figure 1] This flowchart shows an example of the overall flow of the substrate processing method according to the first embodiment of the present invention. [Figure 2] This is a schematic diagram showing an example of a change in the state of a substrate in a film formation method according to the first embodiment of the present invention, where Figure (a) shows the supply of a self-assembled monolayer forming material to the substrate surface, Figure (b) shows the formation of a self-assembled monolayer in the metal film formation region of the substrate surface, and Figure (c) shows the formation of a film in the non-metal film formation region of the substrate surface. [Figure 3] This schematic diagram shows an example of a change in the state of a substrate in a film formation method according to the first embodiment of the present invention, where Figure (a) shows the self-assembled monolayer being irradiated with ultraviolet light, and Figure (b) shows the self-assembled monolayer being removed from the metal film formation region on the substrate surface. [Figure 4]This is an explanatory diagram illustrating the schematic of the supply device in the substrate processing apparatus of the first embodiment of the present invention. [Figure 5] This is an explanatory diagram illustrating the schematic of the removal device in the substrate processing apparatus of the first embodiment of the present invention. [Figure 6] Figure 6(a) is a perspective view showing a schematic of the ultrasonic nozzle in the removal device according to the first embodiment of the present invention, and Figure 6(b) is a longitudinal cross-sectional view showing a schematic of the ultrasonic nozzle. [Figure 7] This flowchart shows an example of the overall flow of the substrate processing method according to the second embodiment of the present invention. [Figure 8] This is an explanatory diagram illustrating the schematic of a removal device in a substrate processing apparatus according to a second embodiment of the present invention. [Figure 9] This is a schematic cross-sectional view of a two-fluid nozzle in a removal device according to a second embodiment of the present invention. [Figure 10] Figures 10(a) and 10(b) show graphs representing the X-ray photoelectron spectra on a Cu film. [Modes for carrying out the invention]

[0029] (First Embodiment) <Substrate Processing Method> A substrate processing method according to the first embodiment of the present invention will be described below with reference to Figures 1 to 3. Figure 1 is a flowchart showing an example of the overall flow of the substrate processing method according to the first embodiment of the present invention. Figures 2(a) to 2(c) are schematic diagrams showing an example of the change in the state of the substrate in the film formation method according to the first embodiment of the present invention. Figure 2(a) shows the supply of the self-assembled monolayer forming material to the substrate surface, Figure 2(b) shows the formation of a self-assembled monolayer in the metal film formation region of the substrate surface, and Figure 2(c) shows the formation of a film in the non-metal film formation region of the substrate surface. Figures 3(a) and 3(b) are schematic diagrams showing an example of the change in the state of the substrate in the film formation method according to the first embodiment of the present invention. Figure 3(a) shows the irradiation of the self-assembled monolayer with ultraviolet light, and Figure 3(b) shows the removal of the self-assembled monolayer in the metal film formation region of the substrate surface.

[0030] The substrate processing method of this embodiment provides a technique for selectively forming a film on the surface of a substrate W according to the material of the substrate surface. In this specification, "substrate" refers to various substrates such as semiconductor substrates, photomask glass substrates, liquid crystal display glass substrates, plasma display glass substrates, FED (Field Emission Display) substrates, optical disc substrates, magnetic disc substrates, and magneto-optical disc substrates.

[0031] As shown in Figure 1, the substrate processing method of this embodiment includes at least a substrate preparation step S101, a self-assembled monolayer formation step S102 for forming a SAM, a film formation step S103, an ultraviolet irradiation step S104 for irradiating the SAM with ultraviolet light, and a removal step S105 for removing the SAM.

[0032] As shown in Figures 1 and 2(a), the substrate W prepared in the substrate preparation step S101 includes a metal film formation region in which the metal film 11 is exposed and a metal film non-formation region in which the insulating film 12 is exposed. More specifically, the substrate W may include, for example, an insulating film 12 in which trenches of an arbitrary wiring width are formed and a metal film 11 embedded in the trenches. The substrate preparation step may include, for example, loading the substrate W into a chamber (details will be described later), which is a container for housing the substrate W, using a substrate loading / unloading mechanism.

[0033] In Figure 2(a), one metal film-forming region and one non-metal film-forming region are formed, but multiple regions of each may be formed. For example, a strip-shaped non-metal film-forming region may be interposed between adjacent strip-shaped metal film-forming regions, or a strip-shaped metal film-forming region may be interposed between adjacent strip-shaped non-metal film-forming regions.

[0034] Furthermore, the substrate W of this embodiment is not limited to a case where only a metal film formation region and a non-metal film formation region are provided on its surface. For example, a region may be provided in which another film made of a material different from the metal film 11 and the insulating film 12 is exposed and formed on the surface. In this case, the position in which such a region is provided is not particularly limited and can be set arbitrarily.

[0035] The metal film 11 is not particularly limited and can be made of, for example, copper (Cu), tungsten (W), ruthenium (Ru), germanium (Ge), silicon (Si), titanium nitride (TiN), cobalt (Co), molybdenum (Mo), etc.

[0036] Furthermore, the insulating film 12 is not particularly limited and can be made of, for example, silicon dioxide (SiO2), hafnium oxide (HfO2), zirconia (ZrO2), silicon nitride (SiN), etc.

[0037] The processing solution used in the SAM formation step S102 contains at least a material 13 for forming the SAM (hereinafter referred to as "SAM forming material") and a solvent. The SAM forming material may be dissolved in the solvent or dispersed in it.

[0038] The SAM-forming material 13 is not particularly limited, and examples include phosphonic acid compounds having a phosphonic acid group, such as monophosphonic acid and diphosphonic acid. These phosphonic acid compounds can be used individually or in combination of two or more.

[0039] Monophosphonic acids are not particularly limited, and examples include phosphonic acid compounds represented by the general formula RP(=O)(OH)2 (wherein R represents an alkyl group having 1 to 18 carbon atoms; an alkyl group having a fluorine atom within the range of 1 to 18 carbon atoms; or a vinyl group). In this specification, when a range of carbon atoms is expressed, that range means that all integer carbon atoms included in that range are included. Therefore, for example, an alkyl group having 1 to 3 carbon atoms means all alkyl groups having 1, 2, and 3 carbon atoms.

[0040] Alkyl groups with 1 to 18 carbon atoms may be linear or branched. Furthermore, the number of carbon atoms in the alkyl group is preferably in the range of 10 to 18, and more preferably in the range of 14 to 18. In addition, alkyl groups with 1 to 18 carbon atoms and containing a fluorine atom may be linear or branched. Furthermore, the number of carbon atoms in the alkyl group containing a fluorine atom is preferably in the range of 10 to 18, and more preferably in the range of 14 to 18.

[0041] Furthermore, specific examples of monophosphonic acids represented by RP(=O)(OH)2 include compounds represented by any of the following chemical formulas (1) to (16).

[0042] [ka]

[0043] In addition to the examples given above, any compound represented by one of the following chemical formulas (17) to (19) can also be used as a monophosphonic acid.

[0044] [ka]

[0045] Examples of diphosphonic acids include compounds represented by either of the following chemical formulas (20) or (21).

[0046] [ka]

[0047] Among the exemplified phosphonic acid compounds, octadecylphosphonic acid and the like are preferred from the viewpoint of forming a dense SAM.

[0048] The solvent in the processing solution is not particularly limited, and examples include alcohol solvents, ether solvents, glycol ether solvents, glycol ester solvents, etc. The alcohol solvent is not particularly limited, and examples include ethanol. The ether solvent is not particularly limited, and examples include tetrahydrofuran (THF). The glycol ether solvent is not particularly limited, and examples include propylene glycol monomethyl ether (PGME). The glycol ester solvent is not particularly limited, and examples include propylene glycol monomethyl ether acetate (PGMEA). These solvents can be used alone or in mixtures of two or more. Furthermore, these solvents can be used in any combination with the phosphonic acid compounds exemplified above. From the viewpoint of being able to dissolve the phosphonic acid compounds among the exemplified solvents, alcohol solvents are preferred, and ethanol is particularly preferred.

[0049] The content of the SAM forming material 13 is preferably in the range of 0.0004% to 0.2% by mass, more preferably in the range of 0.004% to 0.08% by mass, and particularly preferably in the range of 0.02% to 0.06% by mass, relative to the total mass of the processing liquid.

[0050] Furthermore, the processing solution may contain known additives, provided that they do not hinder the effects of the present invention. The additives are not particularly limited and include, for example, stabilizers and surfactants.

[0051] The SAM formation step S102 is a step in which a SAM 14 is formed by bringing a processing liquid into contact with the surface of the substrate W and adsorbing the SAM forming material 13 contained in the processing liquid onto the surface of the metal film 11, as shown in Figures 1, 2(a), and 2(b). Here, the SAM 14 is selectively formed only on the metal film 11 in the metal film formation region of the substrate W, and not in the non-metal film formation region. The reason why the SAM 14 is formed only on the metal film 11 is that, for example, when the metal film 11 is a Cu (copper) film, the phosphonic acid group of the phosphonic acid compound, which is the SAM forming material 13, and the -OH group on the surface of the Cu film react as shown in the following chemical reaction equation.

[0052] [ka]

[0053] The method for bringing the processing solution into contact with the substrate W is not particularly limited, and examples include applying the processing solution to the surface of the substrate W, spraying the processing solution onto the surface of the substrate W, or immersing the substrate W in the processing solution.

[0054] One method for applying the processing solution to the surface of the substrate W is to rotate the substrate W at a constant speed around its center as an axis, and then supply the processing solution to the center of the substrate W's surface. As a result, the processing solution supplied to the surface of the substrate W flows from near the center of the substrate W's surface toward the periphery due to the centrifugal force generated by the rotation of the substrate W, and diffuses across the entire surface of the substrate W. Consequently, the entire surface of the substrate W is covered with the processing solution, and a liquid film of the processing solution is formed.

[0055] The SAM formation process S102 can be carried out, for example, under an inert gas atmosphere.

[0056] The SAM formation process S102 may include a step of removing the processing liquid remaining on the surface of the substrate W. The step of removing the processing liquid is not particularly limited and may include, for example, a step of rotating the substrate W at a constant speed to shake off the processing liquid with centrifugal force.

[0057] Furthermore, when the process involves shaking off the processing liquid using centrifugal force, the rotation speed of the substrate W is not particularly limited as long as it is sufficient to shake off the processing liquid, but it is usually set in the range of 800 rpm to 2500 rpm, preferably 1000 rpm to 2000 rpm, and more preferably 1200 rpm to 1500 rpm.

[0058] As shown in Figures 1 and 2(c), the film formation step S103 is a step in which the target film 15 is formed on the insulating film 12 in the area where the metal film is not formed. At this time, the SAM 14 formed in the metal film formation area functions as a protective film masking the metal film 11. This makes it possible to selectively form the target film 15 in the area where the metal film is not formed.

[0059] The target film 15 is not particularly limited, and examples include films made of aluminum oxide (Al2O3), cobalt oxide (CoO), or zirconium oxide (ZrO2). The method for forming these films 15 is also not particularly limited, and examples include CVD (Chemical Vapor Deposition), ALD (Atomic Layer Deposition), vacuum deposition, sputtering, plating, thermal CVD, and thermal ALD.

[0060] As shown in Figures 1 and 3(a), the ultraviolet irradiation step S104 is a step in which ultraviolet light is irradiated onto the SAM14 to reduce the water repellency of the SAM14.

[0061] This process is carried out in an atmosphere containing oxygen atoms, at least on the surface of the substrate W. For example, when ultraviolet light is irradiated in an atmosphere containing oxygen (O2) and / or moisture (including air), reactive oxygen species such as oxygen atoms, ozone, and OH radicals can be generated. When these reactive oxygen species come into contact with a self-assembled monolayer, they can cleave linear or other bonding portions of the monomolecules (organic compositions) forming the self-assembled monolayer. This reduces the water repellency of the surface of the self-assembled monolayer, thereby modifying the surface. This process may also be carried out in the presence or supply of reactive oxygen species such as oxygen atoms, ozone, and OH radicals.

[0062] The wavelength range of the ultraviolet light used for irradiation is not particularly limited as long as it is 380 nm or less, but from the viewpoint of promoting the reduction of water repellency on the surface of SAM14, it is preferable that it be 254 nm or less.

[0063] The irradiation intensity of ultraviolet light is 1 mW / cm 2 or more and 50 mW / cm 2 or less, preferably 3 mW / cm 2 or more and 30 mW / cm 2 or less, more preferably 5 mW / cm 2 or more and 20 mW / cm 2 or less, particularly preferably. By setting the irradiation intensity of ultraviolet light to 1 mW / cm 2 or more, the water repellency of the SAM14 surface can be reduced, and the wettability of the aqueous self-assembled monolayer removing solution described below with respect to SAM14 can be maintained well.

[0064] The irradiation time of ultraviolet light is preferably 1 minute or more and 60 minutes or less, more preferably 5 minutes or more and 30 minutes or less, and particularly preferably 10 minutes or more and 20 minutes or less. By setting the irradiation time of ultraviolet light to 1 minute or more, the water repellency of the SAM14 surface can be reduced, and the wettability of the aqueous self-assembled monolayer removing solution described below with respect to SAM14 can be maintained well.

[0065] The number of irradiation times of ultraviolet light is not particularly limited, but it is preferably 1 time. Thereby, damage to the film 15 or the like can be prevented or reduced.

[0066] The contact angle (23 °C) of the SAM14 surface after ultraviolet irradiation is preferably 0° or more and 40° or less with respect to DIW (Deionized Water), more preferably 0° or more and 30° or less, and particularly preferably 0° or more and 20° or less. When the contact angle is 40° or less, the wettability with respect to the removing solution can be maintained well. As a result, selective removal of SAM14 can be performed well. Note that the method for measuring the contact angle is not particularly limited, and for example, the method described below can be adopted.

[0067] The removal step S105 is a step to remove the SAM 14 formed in the metal film formation region after the step of forming the film 15 has been performed, as shown in Figures 1 and 3(b). In this step, the removal of SAM 14 is performed by bringing at least the SAM 14 into contact with an aqueous self-assembled monolayer removal solution (hereinafter referred to as "removal solution") to which ultrasonic vibrations have been applied. Since the surface of SAM 14 has been modified in the ultraviolet irradiation step S104 to reduce its water repellency, the wettability of the removal solution to SAM 14 is improved. Therefore, the dissolution of SAM 14 by the removal solution can be performed more effectively. In addition, since ultrasonic vibrations have been applied to the removal solution, when it comes into contact with SAM 14, ultrasonic vibrations can be propagated to SAM 14. As a result, the penetration of the removal solution into SAM 14 is improved, and the peeling of SAM 14 from the substrate W can be promoted. Thus, in this step, as shown in Figure 3(b), a substrate W can be obtained in which the film 15 is selectively formed only in the metal film non-formation region and the metal film 11 is exposed. Here, the removal of SAM14 includes not only cases where SAM14 is dissolved and removed by the removal solution, but also cases where it detaches (peels off) from the substrate W.

[0068] The removal solution is not particularly limited as long as it is aqueous and capable of selectively removing SAM14. Because the removal solution is aqueous, it can exhibit good wettability on the surface of SAM14 that has been surface-modified to reduce its water repellency. In this specification, "aqueous" means a liquid composition that can be diluted with water, or a liquid composition that contains water. Specifically, examples of removal solutions include organic acids such as maleic acid, methylphosphonic acid, and acetic acid, or hydrochloric acid. The removal solution may also contain an aqueous solvent. Examples of aqueous solvents include water.

[0069] The concentration of the organic acid in the removal solution is not particularly limited, but is usually preferably 1% by mass or more and 100% by mass or less, more preferably 1% by mass or more and 50% by mass or less, and particularly preferably 1% by mass or more and 20% by mass or less, relative to the total mass of the removal solution.

[0070] Furthermore, the acid dissociation constant pKa of the removal solution is preferably -4 or greater and 14 or less, more preferably 0 or greater and 10 or less, and particularly preferably 1.96 or greater and 4.76 or less. By using a removal solution with a pKa of -4 or greater, it is possible to prevent or reduce unnecessary etching of metal films 11 such as Cu films or films 15 such as Al2O3 films by the removal solution.

[0071] The method for bringing the removal solution into contact with SAM14 is not particularly limited, and examples include applying the removal solution to the surface of the substrate W, spraying the removal solution onto the surface of the substrate W, or immersing the substrate W in the removal solution.

[0072] One method for applying the removal solution to the surface of the substrate W is to rotate the substrate W at a constant speed around its center as an axis, and then supply the removal solution to the center of the substrate W's surface. As a result, the removal solution supplied to the surface of the substrate W flows from near the center of the substrate W's surface toward the periphery due to the centrifugal force generated by the rotation of the substrate W, and diffuses across the entire surface of the substrate W. Consequently, the entire surface of the substrate W is covered with the removal solution, forming a liquid film of the removal solution.

[0073] The removal process S105 can be carried out, for example, under an inert gas atmosphere.

[0074] The removal step S105 may include a step of removing the removal liquid remaining on the surface of the substrate W. The step of removing the removal liquid is not particularly limited and may include, for example, a step of shaking off the removal liquid by centrifugal force by rotating the substrate W at a constant speed.

[0075] Furthermore, when the removal liquid is shaken off by centrifugal force, the rotation speed of the substrate W is not particularly limited as long as it is sufficient to shake off the removal liquid, but it is usually set in the range of 800 rpm to 2500 rpm, preferably 1000 rpm to 2000 rpm, and more preferably 1200 rpm to 1500 rpm.

[0076] As described above, according to the substrate processing method of this embodiment, the water repellency of the SAM14 is reduced by irradiating it with ultraviolet light before the SAM14 removal step S105, so that the removal liquid can wet the surface of the SAM14 well. Furthermore, since ultrasonic vibrations are applied to the removal liquid as a physical action, when the removal liquid comes into contact with the SAM14, the ultrasonic vibrations are propagated, improving the penetration of the removal liquid into the SAM14 and promoting the peeling of the SAM14 from the substrate W. As a result, the substrate processing method of this embodiment can selectively remove the SAM14 better than conventional substrate processing methods.

[0077] <Substrate Processing Equipment> Next, the substrate processing apparatus according to the first embodiment will be described with reference to Figures 4 to 6. Figure 4 is an explanatory diagram showing the supply device for the removal liquid in the substrate processing apparatus of this embodiment. Figure 5 is an explanatory diagram showing the removal device in the substrate processing apparatus according to this embodiment. Figure 6(a) is a perspective view showing a schematic of the ultrasonic nozzle in the removal device of this embodiment, and Figure 6(b) is a longitudinal cross-sectional view showing a schematic of the ultrasonic nozzle.

[0078] As shown in Figures 4 and 5, the substrate processing apparatus of this embodiment comprises at least a supply device 100 for supplying a removal solution, a removal device 200 for removing the SAM 14, and a control unit 300 for controlling each part of the substrate processing apparatus.

[0079] [Feeding device] As shown in Figure 4, the supply device 100 according to this embodiment has the function of supplying the removal liquid to the removal device 200, and comprises at least a removal liquid tank 111, a pressurizing unit 112, and piping 113.

[0080] The removal liquid tank 111 may include an agitation unit for agitating the treatment liquid inside the removal liquid tank 111, and a temperature control unit for adjusting the temperature of the treatment liquid inside the removal liquid tank 111 (neither of which are shown in the figures). The agitation unit may include a rotating unit for agitating the removal liquid inside the removal liquid tank 111, and an agitation control unit for controlling the rotation of the rotating unit. The agitation control unit is electrically connected to the control unit 300, and the rotating unit may have, for example, a propeller-shaped agitation blade at the lower end of the rotating shaft. The control unit 300 issues an operation command to the agitation control unit to rotate the rotating unit, thereby agitating the removal liquid with the agitation blade. As a result, the concentration and temperature of the removal liquid inside the removal liquid tank 111 can be made uniform.

[0081] The pressurization unit 112 includes a nitrogen gas supply source 116, which is the source of the gas that pressurizes the inside of the removal liquid tank 111; a pump (not shown) for pressurizing the nitrogen gas; a nitrogen gas supply pipe 114; and a valve 115 provided in the middle of the nitrogen gas supply pipe 114. The nitrogen gas supply source 116 is pipely connected to the removal liquid tank 111 by the nitrogen gas supply pipe 114. A pressure sensor (not shown) electrically connected to the control unit 300 can be installed inside the removal liquid tank 111. In this case, the control unit 300 can maintain the pressure inside the removal liquid tank 111 at a predetermined pressure higher than atmospheric pressure by controlling the operation of the pump based on the value detected by the pressure sensor. Also, by electrically connecting the valve 115 to the control unit 300, the opening and closing of the valve 115 can be controlled by operation commands from the control unit 300.

[0082] The piping 113 is connected to the removal device 200 via a pipeline. A valve 113a is provided along the route of the piping 113. The valve 113a is electrically connected to the control unit 300, and the opening and closing of the valve 113a can be controlled by operation commands from the control unit 300. When valves 113a and 115 are opened by operation commands from the control unit 300, the treated liquid is supplied (pressurized) to the removal device 200 via the piping 113.

[0083] [Removal device] Next, the removal device 200 will be explained based on Figure 5. The removal device 200 according to this embodiment is a single-wafer type removal device capable of removing SAM 14 formed on the metal film 11.

[0084] As shown in Figure 5, the removal device 200 includes at least a substrate holding unit 210 for holding the substrate W, a supply unit 220 for supplying removal liquid to the surface Wf of the substrate W, a chamber 230 which is a container for housing the substrate W, a splash-proof cup 240 for collecting the removal liquid, and an ultraviolet irradiation unit 250. The removal device 200 may also include loading / unloading means (not shown) for loading or unloading the substrate W.

[0085] The substrate holder 210 is a means for holding the substrate W, and as shown in Figure 5, it holds the substrate W in a substantially horizontal position with the substrate surface Wf facing upward and rotates it. This substrate holder 210 has a spin chuck 211 in which a spin base 212 and a rotating support shaft 213 are integrally coupled. The spin base 212 has a substantially circular shape in plan view, and a hollow rotating support shaft 213 extending substantially vertically is fixed to its center. The rotating support shaft 213 is connected to the rotation axis of a chuck rotation mechanism 214 including a motor. The chuck rotation mechanism 214 is housed in a cylindrical casing 215, and the rotating support shaft 213 is rotatably supported by the casing 215 around a vertical rotation axis.

[0086] The chuck rotation mechanism 214 can rotate the rotating support shaft 213 around the rotation axis by being driven from the chuck drive unit (not shown) of the control unit 300. As a result, the spin base 212 attached to the upper end of the rotating support shaft 213 rotates around the rotation axis J. The control unit 300 can control the chuck rotation mechanism 214 via the chuck drive unit to adjust the rotation speed of the spin base 212.

[0087] Multiple chuck pins 216 are erected near the periphery of the spin base 212 for gripping the peripheral edge of the substrate W. The number of chuck pins 216 is not particularly limited, but it is preferable to provide at least three or more in order to securely hold the circular substrate W. In this embodiment, three are arranged at equal intervals along the periphery of the spin base 212. Each chuck pin 216 includes a substrate support pin that supports the peripheral edge of the substrate W from below, and a substrate holding pin that presses against the outer peripheral end face of the substrate W supported by the substrate support pin to hold the substrate W.

[0088] The supply unit 220 is positioned above the substrate holding unit 210 and supplies the removal liquid supplied from the supply device 100 onto the surface Wf of the substrate W. As shown in Figures 5, 6(a), and 6(b), the supply unit 220 includes an ultrasonic application unit and an arm 222.

[0089] The ultrasonic application unit comprises an ultrasonic nozzle 221 and an ultrasonic oscillator (not shown). The ultrasonic nozzle 221 is attached to the tip of a horizontally extending arm 222 and is positioned above the spin base 212 when discharging the removal liquid. The ultrasonic nozzle 221 has a body portion 221a and a nozzle tip portion 221b provided at the lower part of the body portion 221a, and its overall shape is a covered cylindrical shape.

[0090] The ultrasonic nozzle 221 has a filling space FS inside which the removal liquid can be filled. The nozzle tip 221b tapers downwards, and as shown in Figure 6(b), its longitudinal cross-sectional shape is approximately V-shaped. The nozzle tip 221b is provided with a discharge port 228 for discharging the removal liquid supplied into the filling space FS toward the surface of the substrate W. The opening area of ​​the discharge port 228 is smaller than the area of ​​the cross-section of the body 221a (a cross-section approximately perpendicular to the discharge direction of the processing liquid). Therefore, the area of ​​the cross-section of the nozzle tip 221b gradually decreases in diameter from the top (cross-section of the body 221a) to the bottom (opening surface of the discharge port 228). A supply port 224 for supplying the removal liquid to the filling space FS is provided on the side of the body 221a. The supply port 224 is connected to the piping 113 of the supply device 100.

[0091] Furthermore, as shown in Figure 6(b), the ultrasonic nozzle 221 is equipped with an ultrasonic transducer 225 inside the body 221a. The ultrasonic transducer 225 is provided on the upper wall surface of the body 221a so as to face the discharge port 228. A cable 226 is electrically connected to the ultrasonic transducer 225, and the cable 226 is electrically connected to an ultrasonic oscillator. The ultrasonic oscillator is further electrically connected to a control unit 300, and in response to operation commands from the control unit 300, the ultrasonic transducer 225 emits ultrasonic waves, imparting ultrasonic vibrations to the removal liquid in the filling space FS. This generates cavitation in the removal liquid, creating minute bubbles. A thin plate of quartz or high-purity SiC (silicon carbide) is attached to the surface of the ultrasonic transducer 225. Furthermore, the ultrasonic nozzle 221 is made of PTFE (polytetrafluoroethylene) or quartz from the viewpoint of chemical resistance, but it may also be constructed by combining a body portion 221a made of PTFE and a nozzle tip portion 221b (or only the area around the discharge port 228) made of quartz.

[0092] Furthermore, the ultrasonic nozzle 221 is provided with a plurality of plate-shaped members 227 below the ultrasonic transducer 225 inside the body portion 221a. It is preferable that the plurality of plate-shaped members 227 are arranged so as not to obstruct the flow of the removal liquid. In Figure 6(b), the plurality of plate-shaped members 227 are arranged at equal intervals from each other and substantially parallel to the discharge direction P of the removal liquid. By providing the plate-shaped members 227, the amount of bubbles generated by cavitation in the removal liquid can be increased. It is preferable that the plate-shaped members 227, like the ultrasonic nozzle 221, be made of a chemical-resistant material.

[0093] Furthermore, as shown in Figure 5, the supply unit 220 also has a supply unit lifting mechanism 223. The supply unit lifting mechanism 223 is connected to the arm 222.

[0094] The supply unit lifting mechanism 223 is electrically connected to the control unit 300, and the supply unit 220 can be raised and lowered in response to operation commands from the control unit 300. This allows the ultrasonic nozzle 221 of the supply unit 220 to move closer to or further away from the substrate W held in the substrate holding unit 210, and the distance between the nozzle and the surface Wf of the substrate W can be adjusted.

[0095] Furthermore, when loading or unloading the substrate W into or out of the removal device 200, the supply unit lifting mechanism 223 is activated by an operation command from the control unit 300, raising the supply unit 220. This allows the ultrasonic nozzle 221 and the surface Wf of the substrate W to be separated by a certain distance, making it easier to load and unload the substrate W.

[0096] The splash-proof cup 240 is positioned to surround the spin base 212. The splash-proof cup 240 is connected to a lifting drive mechanism (not shown) and is capable of moving up and down. When supplying the removal liquid to the surface Wf of the substrate W, the splash-proof cup 240 is positioned in a predetermined position by the lifting drive mechanism and surrounds the substrate W, which is held by the chuck pin 216, from a lateral position. This allows the removal liquid splashing from the substrate W and the spin base 212 to be collected.

[0097] The ultraviolet irradiation unit 250 is positioned inside the removal device 200 above the substrate holding unit 210 (in the direction indicated by arrow Z in Figure 5) so as to be able to irradiate the surface Wf of the substrate W held by the substrate holding unit 210 with ultraviolet light. The ultraviolet irradiation unit 250 comprises at least a plurality of light sources 251 and a quartz glass 252.

[0098] The light source unit 251 shown in Figure 5 is a line light source, and is arranged so that its longitudinal direction is parallel to the direction indicated by Y in Figure 5. Furthermore, each light source unit 251 is arranged in the direction indicated by arrow X so that they are equally spaced from one another. However, the ultraviolet irradiation unit of the present invention is not limited to this embodiment. For example, it may be a ring-shaped ultraviolet irradiation unit, with different diameters arranged concentrically. Alternatively, the ultraviolet irradiation unit may be a point light source. In this case, it is preferable that the multiple ultraviolet irradiation units are arranged so that they are equally spaced from one another in a plane.

[0099] The type of light source 251 is not particularly limited as long as ultraviolet light is emitted, and may include other radiation or wavelength ranges outside the ultraviolet region. Specifically, the light source 251 can be, for example, a low-pressure mercury lamp (main wavelength: 185 nm, 254 nm), a high-pressure mercury lamp (main wavelength: 365 nm), an excimer UV lamp (main wavelength: 272 nm), a metal halide lamp (250~450 nm), and a UV (ultraviolet)-LED (Light Emitting Diode). Furthermore, multiple light sources 251 may be of the same type or different types. When using multiple different types of light sources 251, they can be arranged with different peak wavelengths and light intensities.

[0100] The quartz glass 252 is positioned between the light source unit 251 and the substrate W. The quartz glass 252 is a plate-like body and is installed parallel to the horizontal direction. The quartz glass 252 has light transmittance, heat resistance, and corrosion resistance to ultraviolet light, and transmits ultraviolet light irradiated from the light source unit 251, enabling irradiation of the surface Wf of the substrate W. Furthermore, the quartz glass 252 can protect the light source unit 251 from the atmosphere inside the chamber 253.

[0101] In the above description, the removal device in the substrate processing apparatus of the present invention has been described as a single-wafer type that processes each substrate W individually. However, the substrate processing apparatus of the present invention is not limited to this embodiment, and can also be applied to other forms of the substrate processing apparatus of the present invention, such as a batch type where the removal device processes multiple substrates at once.

[0102] [Control Unit] The control unit 300 is electrically connected to each part of the substrate processing apparatus and controls the operation of each part. The control unit 300 is composed of a computer having an arithmetic unit and a memory unit. A CPU is used as the arithmetic unit to perform various arithmetic operations. The memory unit includes a ROM, which is a read-only memory for storing the substrate processing program, a RAM, which is a read-write memory for storing various information, and a magnetic disk for storing control software and data. Data related to substrate processing conditions is pre-stored on the magnetic disk. Substrate processing conditions include, for example, driving conditions for driving the ultrasonic oscillator, irradiation conditions for ultraviolet irradiation, and conditions for supplying the removal solution to the substrate W. The CPU reads the substrate processing conditions into the RAM and controls each part of the substrate processing apparatus according to its contents.

[0103] (Second Embodiment) <Substrate Processing Method> A substrate processing method according to a second embodiment of the present invention will be described below with reference to Figure 7. Figure 7 is a flowchart showing an example of the overall flow of the substrate processing method according to the second embodiment of the present invention.

[0104] As shown in Figure 7, the substrate processing method of the second embodiment differs from the substrate processing method of the first embodiment in that, in the removal step S105, instead of applying ultrasonic vibration to the removal liquid, a gas is brought into contact with the removal liquid to generate a droplet-shaped removal liquid, and this droplet-shaped removal liquid is used to selectively remove the SAM14. Even with this configuration, selective removal of the SAM14 can be performed effectively. In the following, the preparation step S101 of the substrate W shown in Figure 7, the self-assembled monolayer formation step S102, the film formation step S103, and the ultraviolet irradiation step S104 are the same as in the first embodiment, so their detailed explanations are omitted.

[0105] In the removal step S105' of this embodiment, first, a gas is brought into contact with the removal liquid and mixed to form a mixed fluid consisting of the removal liquid and gas, and this mixed fluid is sprayed and supplied toward the surface of the substrate W. The mixed fluid contains minute droplets of the removal liquid. These droplets of the removal liquid are carried by the gas flow and collide with the surface of the substrate W. This collision applies an impact to the SAM14, promoting the separation of the SAM14 from the surface of the substrate W.

[0106] The gas to be mixed with the removal solution is not particularly limited, and examples include inert gases such as nitrogen gas. By using an inert gas, deterioration of the removal solution can be prevented. The removal process S105' can be carried out, for example, under an inert gas atmosphere.

[0107] The type of removal solution, the concentration of the organic acid contained in the removal solution, the acid dissociation constant pKa, etc., are the same as those described in the first embodiment. Furthermore, the method for removing the removal solution is also the same as described in the first embodiment. Therefore, these details are omitted.

[0108] <Substrate Processing Equipment> Next, a substrate processing apparatus according to the second embodiment will be described with reference to Figures 8 and 9. Figure 8 is an explanatory diagram showing a schematic representation of the removal device in the substrate processing apparatus of this embodiment. Figure 9 is a schematic cross-sectional view showing a two-fluid nozzle in the substrate processing apparatus of this embodiment.

[0109] The substrate processing apparatus of this embodiment differs primarily in that it uses a droplet supply unit 260 as the supply unit in the removal device 200', as shown in Figure 8. The supply device of this embodiment can be one that has basically the same configuration as in the first embodiment (see Figures 4 and 5). Therefore, its description is omitted and the same reference numerals are used.

[0110] The droplet supply unit 260 is positioned above the substrate holding unit 210 and supplies droplets of the removal liquid supplied from the supply device 100 onto the surface Wf of the substrate W. As shown in Figures 8 and 9, the droplet supply unit 260 includes a two-fluid nozzle 261 and an arm 274.

[0111] The two-fluid nozzle 261 generates droplets of the removal liquid by colliding (contacting) a gas with the removal liquid and ejects the droplet-shaped removal liquid. The two-fluid nozzle 261 in this embodiment is an external mixing type two-fluid nozzle that forms a mixed fluid by colliding a gas with the removal liquid outside the casing (nozzle). The two-fluid nozzle 261 comprises an outer cylinder 262 that constitutes the casing and an inner cylinder 263 fitted inside the outer cylinder 262.

[0112] The outer cylinder 262 and the inner cylinder 263 both have a cylindrical shape and are arranged coaxially, sharing a central axis L. The lower end surface 262a of the outer cylinder 262 is a ring-shaped surface perpendicular to the central axis L. The two fluid nozzles 261 are positioned opposite each other so that, at least when spraying droplets of the removal liquid, their central axis L is perpendicular to the surface of the substrate W (i.e., the lower end surface 262a is parallel to the surface of the substrate W).

[0113] An internal space 264 is formed in the inner cylinder 263 along the central axis L to give it a cylindrical shape. This internal space 264 opens in a circular shape at the lower end of the inner cylinder 263. The upper end of the internal space 264 is connected by pipeline to the piping 113 of the supply device 100. The removal liquid supplied from the supply device 100 via the piping 113 flows into the internal space 264 and is discharged (discharged downward along the central axis L) from the opening 265 at its lower end. In other words, the internal space 264 functions as a flow path for the removal liquid, and the opening 265 functions as a discharge port for the removal liquid. Hereafter, the internal space 264 will also be referred to as the "removal liquid flow path 264". The opening 265 at the lower end of the internal space 264 will also be referred to as the "removal liquid discharge port 265".

[0114] The inner cylinder 263 comprises a large-diameter portion 263a and a small-diameter portion 263b that is continuously provided below the large-diameter portion 263a. The small-diameter portion 263b has a smaller outer diameter than the large-diameter portion 263a. The inner diameter of the outer cylinder 262 fitted to the outside of the inner cylinder 263 is equal to the outer diameter of the large-diameter portion 263a, and the outer cylinder 262 has a substantially constant inner diameter except for its lower end portion. A gap 266 is formed between the outer surface of the small-diameter portion 263b and the inner surface of the outer cylinder 262. This gap 266 is a ring-shaped space with a cross-section centered on a central axis L, and opens in a ring shape (i.e., a ring shape surrounding the removal liquid discharge port 265) at the lower end of the outer cylinder 262.

[0115] Near the upper end of the gap 266, one end of an inlet pipe 267, which penetrates the inner and outer surfaces of the outer cylinder 262, is connected. The other end of the inlet pipe 267 is connected to a pipe 273a (described later) which is connected to a gas supply source 273. The gas supplied from the gas supply source 273 via the pipe 273a and the inlet pipe 267 flows into the gap 266 and is discharged from the opening 268 at its lower end. In other words, the gap 266 is a gas flow path, and the opening 268 is a gas discharge port. Hereafter, the gap 266 will also be referred to as the "gas flow path 266". The opening 268 at the lower end of the gap 266 will also be referred to as the "gas discharge port 268".

[0116] Near the lower end of the small-diameter portion 263b, a flange 269 is formed that protrudes radially outward from its outer surface. A through-hole 270 is formed in the flange 269, and when the gas flowing into the gas passage 266 passes through this through-hole 270, its flow direction is changed, and it flows as a swirling flow that rotates around the central axis L.

[0117] In the small-diameter portion 263b, below the portion where the flange 269 is formed, a cylindrical short section 271 is formed that protrudes from the lower surface of the flange 269 along the central axis L. The short section 271 is positioned so that its central axis coincides with the central axis L. The outer diameter of the short section 271 is smaller than the inner edge diameter of the lower end surface 262a of the outer cylinder 262. Therefore, the aforementioned opening 268 is formed in a ring shape surrounding the central axis L between the lower end surface of the short section 271 and the lower end surface 262a of the outer cylinder 262.

[0118] The inner wall surface of the outer cylinder 262, surrounding the short cylinder portion 271, is formed in a tapered shape, with the inner diameter decreasing as it goes downwards. Therefore, the swirling flow of gas flowing into the space 272 surrounding the short cylinder portion 271 becomes a spiral airflow that approaches the central axis L as it swirls within the space 272, and is discharged from the gas outlet 268. The spiral airflow discharged from the gas outlet 268 flows around the removal liquid discharged from the removal liquid outlet 265 along the central axis L, and proceeds to converge at a certain convergence point F on the central axis L. At and near the convergence point F, the removal liquid and gas collide and mix, forming droplet-shaped removal liquid. Furthermore, the generated droplet-shaped removal liquid is accelerated by the gas airflow to become a jet.

[0119] The droplet supply unit 260 also has a droplet supply unit lifting mechanism 223'. The droplet supply unit lifting mechanism 223' is connected to the arm 274.

[0120] The droplet supply unit lifting mechanism 223' is electrically connected to the control unit 300', and the droplet supply unit 260 can be raised and lowered in response to operation commands from the control unit 300'. This allows the two-fluid nozzles 261 of the droplet supply unit 260 to move closer to or further away from the substrate W held by the substrate holding unit 210, thereby adjusting the distance between the nozzles and the surface Wf of the substrate W.

[0121] As mentioned above, the two-fluid nozzle 261 is connected to the gas supply source 273 via piping 273a. A valve 273b is provided along the path of piping 273a.

[0122] Valve 273b is electrically connected to the control unit 300', and the opening and closing of valve 273b can be controlled by the operation commands of the control unit 300'. Similarly, the opening and closing of valve 113a of the supply device 100 that supplies the removal liquid is also controlled by the operation commands of the control unit 300'. Therefore, the discharge pattern of the removal liquid discharged from the two-fluid nozzle 261 (specifically, the discharge start timing, discharge end timing, type of discharged droplets, discharge flow rate, force of discharged droplets, etc.) can be controlled by the control unit 300'.

[0123] In this embodiment, an external mixing type two-fluid nozzle was used as an example of the two-fluid nozzle 261. However, the present invention is not limited to this embodiment. For example, an internal mixing type two-fluid nozzle that generates droplet-shaped removal liquid by colliding gas with the removal liquid inside the casing can also be used.

[0124] [Control Unit] The control unit 300' is composed of a computer having an arithmetic unit and a storage unit, similar to the first embodiment. The magnetic disk of the storage unit contains irradiation conditions for ultraviolet irradiation, as well as supply conditions for supplying droplets of the removal solution to the substrate W. The CPU used in the arithmetic unit reads the substrate processing conditions into RAM, similar to the first embodiment, and controls each part of the substrate processing apparatus according to its contents.

[0125] (Other matters) The supply device and removal device of this embodiment may be used in various devices other than substrate processing devices, or they may be used independently. The above description describes the most preferred embodiment of the present invention. However, the present invention is not limited to this embodiment. The components in the above-described embodiments and each of the modifications can be changed, modified, substituted, added, deleted, and combined within a range that is not contradictory to each other. For example, in each embodiment, a method of removing SAM by applying ultrasonic vibration to the removal liquid or by spraying the removal liquid onto the SAM surface in droplet form was described. However, the present invention is not limited to this embodiment. The present invention only requires that the SAM be irradiated with at least ultraviolet light to reduce its water repellency before the SAM removal step. [Examples]

[0126] Preferred embodiments of this invention are described in detail below. However, unless otherwise specified, the materials, proportions, conditions, etc., described in these embodiments do not limit the scope of this invention to those described.

[0127] (Example 1) [Preparation process for the circuit board] First, a substrate was prepared in which a Cu film (thickness 100 nm, metal film formation region) was formed on the surface as a metallic film.

[0128] [Formation of SAM and Al2O3 films] Octadecylphosphonic acid (CH3(CH2)) as a SAM-forming material 17 A treatment solution was prepared by dissolving P(=O)(OH)2) (pKa=2.1, pH=3.0) in ethanol solvent. The concentration of octadecylphosphonic acid was set to 0.05% by mass relative to the total mass of the treatment solution.

[0129] Next, the treatment solution was applied to the surface of the substrate, and a SAM film was formed in which octadecylphosphonic acid was adsorbed onto the Cu film.

[0130] Furthermore, an Al2O3 film (thickness 5 nm) was formed on the surface of the substrate. Specifically, the Al2O3 film was deposited by ALD using an atomic layer deposition apparatus (product name: SUNALE-R, manufactured by PICOSUN Corporation).

[0131] [Ultraviolet irradiation process] Next, the surface of the SAM was irradiated with ultraviolet light to modify its surface so that its water repellency was reduced. The ultraviolet irradiation conditions were as follows: Light source for UV irradiation: Low-pressure mercury lamp (product name: EUV200WS-51, manufactured by Sen Special Light Source Co., Ltd.) Peak wavelengths of ultraviolet light: 185nm, 254nm UV irradiation intensity: 10 mW / cm² 2 UV exposure time: 0.25 hours Chamber pressure: Atmospheric pressure Chamber temperature: 25℃ Chamber atmosphere: air

[0132] [SAM removal] Next, the SAM was removed from the substrate on which the Al2O3 film was formed. Specifically, the substrate was immersed in a 1% by mass aqueous solution of acetic acid (pKa=4.76, pH=2.7) to selectively remove the SAM. This prepared the sample according to this example.

[0133] (Comparative Example 1) In this comparative example, the SAM removal process was performed without the ultraviolet irradiation process after the formation of the Al2O3 film. Otherwise, the sample for this comparative example was prepared in the same manner as in Example 1.

[0134] (Comparative Example 2) In this comparative example, instead of a 1% by mass aqueous acetic acid solution, a mixed solution of hydrochloric acid, IPA (isopropyl alcohol), and DIW was used as the removal solution, with a mass ratio of hydrochloric acid:IPA:DIW = 1:50:50. Furthermore, the SAM removal process was performed without the ultraviolet irradiation process after the formation of the Al2O3 film. Otherwise, the sample for this comparative example was prepared in the same manner as in Example 1.

[0135] (Evaluation of surface condition) The surface state of the Cu film on each substrate of Example 1 and Comparative Examples 1 and 2 was analyzed and evaluated. Specifically, the surface state of the Cu film was analyzed using X-ray photoelectron spectroscopy (XPS). The results are shown in Figures 10(a) and 10(b). Figures 10(a) and 10(b) are graphs representing the X-ray photoelectron spectra on the Cu film.

[0136] As can be seen from Figures 10(a) and 10(b), in each substrate of Example 1 and Comparative Examples 1 and 2, the strongest peak appeared at the binding energy value specific to Cu atoms on the Cu film. Furthermore, in each substrate of Comparative Examples 1 and 2, a peak also appeared at the binding energy value specific to Al atoms. This confirmed that in Comparative Examples 1 and 2, Al atoms that remained in the SAM during the formation of the Al2O3 film remained even after the SAM removal process. As a result, it was inferred that in these comparative examples, the SAM was not properly removed from the Cu film and remained. On the other hand, in Example 1, no peak appeared at the binding energy value specific to Al atoms. This confirmed that in Example 1, the SAM was properly selectively removed from the Cu film.

[0137] (Measurement of contact angle) The contact angle of the DIW on the surface of the Cu film was measured using (product name: DMo-701, manufactured by Kyowa Interface Science Co., Ltd.) under the following conditions. Measurements were taken at five different locations, and the average value was calculated as the contact angle. The results are shown in Table 1. • Measurement environment: 23°C, 50% RH ·Dropped amount: 2μL • Time from droplet placement to measurement: 1 second

[0138] [Table 1]

[0139] (Example 2) In this example, instead of a 1% by mass aqueous solution of acetic acid, a 10% by mass aqueous solution of maleic acid (pKa=1.96, pH=1.3) was used as the removal solution. Otherwise, the sample according to this example was prepared in the same manner as in Example 1.

[0140] (Example 3) In this example, instead of a 1% by mass aqueous acetic acid solution, a 10% by mass aqueous maleic acid solution (pKa=1.96, pH=1.3) was used as the removal solution. Furthermore, during the removal process, ultrasonic vibration was applied to the aqueous maleic acid solution when immersing the substrate in it to selectively remove the SAM. The sample according to this example was prepared in the same manner as in Example 1.

[0141] (Example 4) In this example, instead of a 1% by mass aqueous solution of acetic acid, a 10% by mass aqueous solution of methylphosphonic acid (pKa=2.36, pH=1.1) was used as the removal solution. Otherwise, the sample according to this example was prepared in the same manner as in Example 1.

[0142] (Example 5) In this example, instead of a 1% by mass aqueous acetic acid solution, a 10% by mass aqueous methylphosphonic acid solution (pKa=2.36, pH=1.1) was used as the removal solution. Furthermore, during the removal process, when immersing the substrate in the aqueous methylphosphonic acid solution, ultrasonic vibration was applied to the aqueous methylphosphonic acid solution to selectively remove the SAM. The sample according to this example was prepared in the same manner as in Example 1, except for these differences.

[0143] (Example 6) In this example, instead of a 1% by mass aqueous solution of acetic acid, 100% by mass acetic acid (pKa=4.76) was used as the removal solution. Otherwise, the sample according to this example was prepared in the same manner as in Example 1.

[0144] (Example 7) In this example, instead of a 1% by mass aqueous solution of acetic acid, 100% by mass acetic acid (pKa=4.76) was used as the removal solution. Furthermore, during the removal process, ultrasonic vibration was applied to the acetic acid when immersing the substrate in it to selectively remove the SAM. The sample according to this example was prepared in the same manner as in Example 1, except for these differences.

[0145] (Evaluation of removal performance) The removal performance of SAM in each sample from Examples 2 to 7 was evaluated based on the residue ratio of Al atoms on the Cu film. Specifically, for each sample, cross-sectional images were observed using a transmission electron microscope (TEM), and elemental analysis of the observed area was performed using energy-dispersive X-ray spectroscopy (EDX). The elemental analysis by EDX targeted Al atoms in the Al2O3 and Cu films. Furthermore, the residue ratio of Al atoms on the Cu film was calculated based on the following formula. The results are shown in Table 2. (Al atom residue ratio) = (Al atomic weight on Cu film) / (Al atomic weight in Al2O3 film) × 100 (%)

[0146] In all of the samples from Examples 2 to 7, it was confirmed that the residue ratio of Al atoms could be suppressed. In particular, in Examples 3, 5, and 7, where ultrasonic vibration was applied to the removal solution to remove SAM, the residue ratio of Al atoms was suppressed to 10% or less in all cases. Al atoms remain in SAM due to the formation of the Al2O3 film. Therefore, the less residue of Al atoms there is on the Cu film after SAM removal, the better the SAM is selectively removed from the Cu film. In each of the samples from Examples 2 to 7, the residue ratio of Al atoms on the Cu film was suppressed, and in particular, the suppression of the residue ratio of Al atoms was good in Examples 3, 5, and 7. Therefore, it can be said that the removal solutions used in each of Examples 2 to 7 are all excellent at removing SAM.

[0147] Furthermore, in each sample from Examples 2 to 7, we also confirmed the extent to which etching of the Cu and Al2O3 films was suppressed before and after SAM removal. Specifically, we measured the film thickness of the Cu and Al2O3 films before and after SAM removal using TEM observation and calculated the decrease in film thickness of the Cu and Al2O3 films. The results are shown in Table 2. As can be seen from Table 2, in all samples from Examples 2 to 7, we were able to suppress the decrease in film thickness of the Cu and Al2O3 films. In particular, in Examples 2, 3, 6, and 7, the decrease in Al2O3 film thickness was suppressed to 0.5 nm or less compared to the initial film thickness of 5 nm. In Example 7, the decrease in Cu film thickness was suppressed to 3 nm or less compared to the initial film thickness of 100 nm. As a result, etching of the Cu film and Al2O3 film was suppressed in each sample from Examples 2 to 7. In particular, etching of the Al2O3 film was well suppressed in Examples 2, 3, 6, and 7, and etching of the Cu film was well suppressed in Example 7. Therefore, it can be said that the substrate processing methods in Examples 2 to 7 are all excellent for the selective removal of SAM.

[0148] [Table 2] [Explanation of symbols]

[0149] 11… Metal film 12… Insulating film 13…Self-assembled monolayer (SAM) forming material 14…Self-assembled monolayer (SAM) 15...Membrane 100…Feeding device 111...Removal liquid tank 114... Nitrogen gas supply pipe 116… Nitrogen gas supply source 200...Removal device 210...Substrate holding part 211... Spin Chuck 212... Spin base 213... Rotary pivot shaft 214...Chuck rotation mechanism 215...Casing 216... Chuck pin 220…Supply section 221... Ultrasonic nozzle 221b... Nozzle tip 221a...Body 222, 274... Arm 223... Supply Unit Lifting Mechanism 223'... Droplet supply unit lifting mechanism 224... Supply port 225... Ultrasonic transducer 228…Discharge port 240...Splash-proof cup 250... UV irradiation area 251...Light source section 252...Quartz glass 253... Chamber 260...Droplet supply section 261…2-fluid nozzle 273... Gas supply source 273a... Piping 273b... Valve 300... Control Unit S101…Preparation process S102…Self-assembled monolayer (SAM) formation process S103…Membrane formation process S104…Ultraviolet irradiation process S105…Removal process W... Circuit board Wf…Surface of the substrate

Claims

1. A substrate processing method for processing a substrate having a metal film forming region in which a metal film is exposed and a metal film non-forming region in which an insulating film is exposed, A self-assembled monolayer formation step in which a self-assembled monolayer is formed on the metal film, A film formation step in which the self-assembled monolayer is used as a protective film for the metal film and a film is formed on the insulating film, A UV irradiation step is performed to reduce the water repellency of the surface of the self-assembled monolayer by irradiating the self-assembled monolayer with ultraviolet light in an atmosphere containing oxygen atoms. A removal step is to contact the self-assembled monolayer after the ultraviolet irradiation step with an aqueous self-assembled monolayer removal solution, thereby selectively removing the self-assembled monolayer. A substrate processing method including the following.

2. The removal step is The substrate processing method according to claim 1, comprising the step of bringing the aqueous self-assembled monolayer removal solution into contact with the self-assembled monolayer after the ultraviolet irradiation step while applying a physical action to the aqueous self-assembled monolayer removal solution.

3. The removal step is The substrate processing method according to claim 2, comprising the step of applying ultrasonic vibrations to the aqueous self-assembled monolayer removal solution while bringing the aqueous self-assembled monolayer removal solution into contact with the self-assembled monolayer after the ultraviolet irradiation step, thereby selectively removing the self-assembled monolayer.

4. The removal step is The substrate processing method according to claim 2, comprising the step of selectively removing the self-assembled monolayer by contacting the self-assembled monolayer with the aqueous self-assembled monolayer removal solution, which is generated in droplet form by contacting the self-assembled monolayer with a gas.

5. The irradiation intensity of the aforementioned ultraviolet light is 1 mW / cm². ２ Above, 50mW / cm ２ A substrate processing method according to any one of claims 1 to 4, within the following range.

6. The substrate treatment method according to any one of claims 1 to 4, wherein the aqueous self-assembled monolayer removal solution contains at least an organic acid.

7. The substrate processing method according to any one of claims 1 to 4, wherein the acid dissociation constant pKa of the aqueous self-assembled monolayer removal solution is -4 or greater and 14 or less.

8. The substrate processing method according to any one of claims 1 to 4, wherein the contact angle of the surface of the self-assembled monolayer after the ultraviolet irradiation step is 0° or more and 40° or less with respect to the DIW at 23°C.

9. A substrate processing method for processing a substrate having a self-assembled monolayer provided on its surface, A UV irradiation step is performed to reduce the water repellency of the surface of the self-assembled monolayer by irradiating the self-assembled monolayer with ultraviolet light in an atmosphere containing oxygen atoms. A removal step is to contact the self-assembled monolayer after the ultraviolet irradiation step with an aqueous self-assembled monolayer removal solution, thereby selectively removing the self-assembled monolayer. Includes, A substrate processing method wherein the irradiation intensity of the ultraviolet light is in the range of 1 mW / cm² or more and 50 mW / cm² or less.

10. A substrate processing method for processing a substrate having a self-assembled monolayer provided on its surface, A UV irradiation step is performed to reduce the water repellency of the surface of the self-assembled monolayer by irradiating the self-assembled monolayer with ultraviolet light in an atmosphere containing oxygen atoms. A removal step is to contact the self-assembled monolayer after the ultraviolet irradiation step with an aqueous self-assembled monolayer removal solution, thereby selectively removing the self-assembled monolayer. Includes, The aqueous self-assembled monolayer removal solution is a substrate treatment method containing at least an organic acid.

11. A substrate processing apparatus having a metal film forming region in which a metal film is exposed and a metal film non-forming region in which an insulating film is exposed, A UV irradiation section that emits ultraviolet light, A supply unit that supplies an aqueous self-assembled monolayer removal solution to the surface of the substrate, A control unit that controls the ultraviolet irradiation unit and the supply unit, Equipped with, The substrate has a self-assembled monolayer formed on the metal film, and a film formed on the insulating film with the self-assembled monolayer as a protective film for the metal film. The control unit, The UV irradiation section is irradiated with ultraviolet light in an atmosphere containing oxygen atoms, thereby reducing the water repellency of the surface of the self-assembled monolayer. A substrate processing apparatus that supplies the aqueous self-assembled monolayer removal solution to the surface of the substrate via the supply unit, thereby selectively removing the self-assembled monolayer.

12. The supply unit is equipped with an ultrasonic application unit, The substrate processing apparatus according to claim 11, wherein the control unit controls the ultrasonic application unit to apply ultrasonic vibrations to the aqueous self-assembled monolayer removal solution.

13. The supply unit is a droplet supply unit that supplies the aqueous self-assembled monolayer removal solution in droplet form. The substrate processing apparatus according to claim 11, wherein the control unit controls the droplet supply unit to bring gas into contact with the aqueous self-assembled monolayer removal solution to generate droplets of the aqueous self-assembled monolayer removal solution and spray them toward the self-assembled monolayer.

14. The control unit controls the ultraviolet irradiation unit to set the ultraviolet irradiation intensity to 1 mW / cm². ２ Above, 50mW / cm ２ A substrate processing apparatus according to any one of claims 11 to 13, wherein the range is as follows:

15. The substrate processing apparatus according to any one of claims 11 to 13, wherein the aqueous self-assembled monolayer removal solution contains at least an organic acid.

16. The substrate processing apparatus according to any one of claims 11 to 13, wherein the acid dissociation constant pKa of the aqueous self-assembled monolayer removal solution is -4 or greater and 14 or less.

17. The substrate processing apparatus according to any one of claims 11 to 13, wherein the contact angle of the self-assembled monolayer surface after irradiation with ultraviolet light is 0° or more and 40° or less with respect to the DIW at 23°C.

18. A substrate processing apparatus for processing a substrate having a self-assembled monolayer on its surface, A UV irradiation section that emits ultraviolet light, A supply unit that supplies an aqueous self-assembled monolayer removal solution to the surface of the substrate, A control unit that controls the ultraviolet irradiation unit and the supply unit, Equipped with, The control unit, The UV irradiation section is irradiated with ultraviolet light in an atmosphere containing oxygen atoms, with an irradiation intensity in the range of 1 mW / cm² or more and 50 mW / cm² or less, thereby reducing the water repellency of the surface of the self-assembled monolayer. A substrate processing apparatus that supplies the aqueous self-assembled monolayer removal solution to the surface of the substrate via the supply unit, thereby selectively removing the self-assembled monolayer.

19. A substrate processing apparatus for processing a substrate having a self-assembled monolayer on its surface, A UV irradiation section that emits ultraviolet light, A supply unit that supplies an aqueous self-assembled monolayer removal solution to the surface of the substrate, A control unit that controls the ultraviolet irradiation unit and the supply unit, Equipped with, The aqueous self-assembling monolayer removal solution contains at least an organic acid, The control unit, The UV irradiation section is irradiated with ultraviolet light in an atmosphere containing oxygen atoms, thereby reducing the water repellency of the surface of the self-assembled monolayer. A substrate processing apparatus that supplies the aqueous self-assembled monolayer removal solution to the surface of the substrate via the supply unit, thereby selectively removing the self-assembled monolayer.

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