JP2024044190A - SUBSTRATE PROCESSING METHOD AND SUBSTRATE PROCESSING APPARATUS - Google Patents

Abstract

The present invention provides a substrate processing method and a substrate processing apparatus that can selectively remove a self-assembled monolayer provided on the surface of a substrate.
The present invention is a substrate processing method for processing a substrate W having a self-assembled monolayer 14 on its surface, in which the self-assembled monolayer 14 is exposed to ultraviolet light in an atmosphere containing oxygen atoms. An ultraviolet irradiation step S104 in which the water repellency of the surface of the self-assembled monolayer film 14 is reduced by irradiation with the ultraviolet rays, and an aqueous self-assembled monolayer removal solution is applied to the self-assembled monolayer film 14 after the ultraviolet irradiation step. and a removal step S105 in which the self-assembled monolayer 14 is selectively removed by contacting the self-assembled monolayer 14.
[Selection diagram] Figure 1

Description

The present invention relates to a substrate processing method and a substrate processing apparatus that are capable of selectively removing a self-assembled monolayer provided on the surface of a substrate.

In the manufacture of semiconductor devices, photolithography is widely used as a technique for selectively forming a film on a specific surface region of a substrate. For example, after forming the lower wiring, an insulating film is formed, and then a dual damascene structure with trenches and via holes is formed by photolithography and etching, and a conductive film such as Cu is embedded in the trenches and via holes to form wiring.

However, in recent years, semiconductor devices have become increasingly miniaturized, and there are cases where the alignment precision of photolithography technology is insufficient. As a result, there is a demand for an alternative to photolithography technology, a method for selectively forming a film with high precision in a specific area on the substrate surface.

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

However, the film forming method disclosed in Patent Document 1 has a problem in that selective removal of SAM by acetic acid is not sufficient.

U.S. Pat. No. 10,867,850

The present invention has been made in consideration of the above problems, and its purpose is to provide a substrate processing method and substrate processing apparatus that can effectively and selectively remove a self-assembled monolayer formed on the surface of a substrate.

In order to solve the above problems, the substrate processing method of the present invention is a substrate processing method for processing a substrate having a self-assembled monolayer formed on its surface, and is characterized by including an ultraviolet irradiation step of irradiating the self-assembled monolayer with ultraviolet light in an atmosphere containing oxygen atoms to reduce the water repellency of the surface of the self-assembled monolayer, and a removal step of contacting the self-assembled monolayer after the ultraviolet irradiation step with an aqueous self-assembled monolayer removal solution, thereby selectively removing the self-assembled monolayer.

According to the above configuration, in the ultraviolet irradiation step, ultraviolet rays are irradiated in the presence of oxygen atoms. More specifically, for example, ultraviolet rays are irradiated in an atmosphere containing oxygen (O ₂ ) and moisture, or in a state where oxygen is supplied. As a result, active oxygen species such as oxygen atoms, ozone, and OH radicals are generated. Alternatively, the ultraviolet irradiation may be performed while supplying active oxygen species. Thereby, it is possible to cleave bonding portions such as linear chains of single molecules (organic composition) forming the self-assembled monolayer. As a result, the water repellency of the surface of the self-assembled monolayer can be reduced and modified.

In the removal step, an aqueous self-assembled monolayer removal solution is supplied to the self-assembled monolayer after irradiation with ultraviolet rays. Since the water repellency of the surface of the self-assembled monolayer is reduced by ultraviolet irradiation, the wettability with the aqueous self-assembled monolayer removal solution is improved. This makes it easier for the aqueous self-assembled monolayer removal solution to spread on the surface of the self-assembled monolayer, thereby promoting the removal of the self-assembled monolayer.

That is, with the substrate processing method having the above structure, the self-assembled monomolecular film provided on the surface of the substrate can be selectively removed better than in conventional substrate processing methods.

In the above configuration, the removal step is preferably a step of contacting the aqueous self-assembled monolayer removal solution 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, when the aqueous self-assembled monolayer removal solution comes into contact with the self-assembled monolayer, this physical action can be indirectly applied to the self-assembled monolayer. As a result, the peeling of the self-assembled monolayer from the substrate can be promoted, and the selective removal of the self-assembled monolayer can be more effectively performed.

In the above configuration, the removal step may be a step of contacting the aqueous self-assembled monolayer removal solution with the self-assembled monolayer after the ultraviolet irradiation step while applying ultrasonic vibration to the aqueous self-assembled monolayer removal solution, thereby selectively removing the self-assembled monolayer. By applying ultrasonic vibration as a physical action to the aqueous self-assembled monolayer removal solution supplied to the surface of the self-assembled monolayer, the ultrasonic vibration can be propagated to the self-assembled monolayer when the aqueous self-assembled monolayer removal solution contacts the self-assembled monolayer. As a result, the self-assembled monolayer is promoted to peel off from the substrate, and the selective removal of the self-assembled monolayer can be performed more effectively.

Further, in the above configuration, the removing step removes the aqueous self-assembled monolayer removal liquid in the form of droplets, which is generated by contacting the aqueous self-assembled monolayer removal liquid with a gas. It may be a step of selectively removing the self-assembled monolayer by bringing it into contact with the self-assembled monolayer. By bringing gas into physical contact with the aqueous self-assembled monolayer removal solution supplied to the surface of the self-assembled monolayer, the droplet-shaped aqueous self-assembled monolayer removal solution is removed from the self-assembled monolayer. It can be brought into contact with the molecular membrane by colliding with it. The impact promotes peeling of the self-assembled monolayer from the substrate, making it possible to selectively remove the self-assembled monolayer even better.

In the above configuration, the irradiation intensity of the ultraviolet rays is preferably in a range of 1 mW/cm ² or more and 50 mW/cm ² or less. By setting the ultraviolet irradiation intensity to 1 mW/ ^cm2 or more, the water repellency of the surface of the self-assembled monolayer can be favorably reduced, and the wettability of the aqueous self-assembled monolayer removal solution to the self-assembled monolayer can be improved. can be maintained in good condition.

In the above-mentioned configuration, it is preferable that the aqueous self-assembled monolayer removal liquid contains at least an organic acid. By containing an organic acid in the aqueous self-assembled monolayer removal liquid, the wettability and permeability of the aqueous self-assembled monolayer removal liquid to the self-assembled monolayer can be further improved. This makes it possible to more effectively selectively remove the self-assembled monolayer.

In the above-mentioned configuration, the acid dissociation constant pKa of the aqueous self-assembled monolayer removing solution is preferably not less than −4 and not more than 14. By making the acid dissociation constant pKa of the aqueous self-assembled monolayer removing solution −4 or more, even when, for example, a metal film such as a Cu film or an Al ₂ O ₃ film is provided on a substrate, it is possible to prevent or reduce unnecessary etching of these films by the aqueous self-assembled monolayer removing solution.

In order to solve the above problems, the substrate processing apparatus of the present invention is a substrate processing apparatus for processing a substrate having a self-assembled monolayer formed on its surface, and includes an ultraviolet irradiation unit for irradiating ultraviolet rays, a supply unit for supplying an aqueous self-assembled monolayer removal liquid to the surface of the substrate, and a control unit for controlling the ultraviolet irradiation unit and the supply unit, and the control unit causes the ultraviolet irradiation unit to irradiate the self-assembled monolayer with ultraviolet rays in an atmosphere containing oxygen atoms, 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 removal liquid to the surface of the substrate, thereby selectively removing the self-assembled monolayer.

According to the above configuration, the control unit causes the ultraviolet irradiation unit to irradiate the self-assembled monolayer with ultraviolet light in an atmosphere containing oxygen atoms. More specifically, for example, the ultraviolet light is irradiated in an atmosphere containing oxygen (O ₂ ) and moisture, or in a state where oxygen is supplied. This generates active oxygen species such as oxygen atoms, ozone, and OH radicals. Alternatively, the control unit causes the ultraviolet irradiation unit to irradiate ultraviolet light while the active oxygen species is being supplied. This makes it possible to break bonds such as linear chains of monomolecules (organic compositions) that form the self-assembled monolayer. As a result, the water repellency of the surface of the self-assembled monolayer can be reduced and modified.

Further, the control unit causes the supply unit to supply an aqueous self-assembled monolayer removal liquid to the self-assembled monolayer after being irradiated with ultraviolet rays. Since the surface of the self-assembled monolayer film has reduced water repellency due to the ultraviolet irradiation from the ultraviolet irradiation unit, its wettability with respect to the aqueous self-assembled monolayer removal solution is improved. This makes it easier for the aqueous self-assembled monolayer removal solution to spread on the surface of the self-assembled monolayer, thereby promoting the removal of the self-assembled monolayer.

In other words, the substrate processing apparatus having the above configuration can selectively remove the self-assembled monolayer formed on the surface of the substrate better than conventional substrate processing apparatuses.

In the above configuration, the supply unit may include an ultrasonic wave applying unit, and the control unit may apply ultrasonic vibrations to the aqueous self-assembled monolayer removal solution by controlling the ultrasonic wave applying unit. This allows the aqueous self-assembled monolayer removal solution to which ultrasonic vibrations have been applied to be supplied to the self-assembled monolayer, and when the aqueous self-assembled monolayer removal solution comes into contact with the self-assembled monolayer, the ultrasonic vibrations can be propagated to the self-assembled monolayer. As a result, the self-assembled monolayer is promoted to peel off from the substrate, and the selective removal of the self-assembled monolayer can be more effectively performed.

In the above configuration, the supply unit is a droplet supply unit that supplies the aqueous self-assembled monolayer removal liquid in droplet form, and the control unit may control the droplet supply unit to bring the aqueous self-assembled monolayer removal liquid into contact with a gas to generate the aqueous self-assembled monolayer removal liquid in droplet form and spray it toward the self-assembled monolayer. By using the droplet supply unit as the supply unit, the aqueous self-assembled monolayer removal liquid in droplet form can be supplied by colliding with the self-assembled monolayer. The impact promotes peeling of the self-assembled monolayer from the substrate, and the selective removal of the self-assembled monolayer can be performed more effectively.

In the above configuration, it is preferable that the control unit sets the irradiation intensity of the ultraviolet rays to a range of 1 mW/cm ² or more and 50 mW/cm ² or less by controlling the ultraviolet irradiation unit. By controlling the ultraviolet irradiation unit so that the ultraviolet irradiation intensity is 1 mW/cm ² or more, the control unit can satisfactorily reduce the water repellency of the surface of the self-assembled monolayer, and form an aqueous self-assembled monolayer. The wettability of the removal liquid to the self-assembled monolayer can be maintained well.

In the above-mentioned configuration, it is preferable that the aqueous self-assembled monolayer removal liquid contains at least an organic acid. By containing an organic acid in the aqueous self-assembled monolayer removal liquid, the wettability and permeability of the aqueous self-assembled monolayer removal liquid to the self-assembled monolayer can be improved. This makes it possible to more effectively selectively remove the self-assembled monolayer.

In the above configuration, it is preferable that the acid dissociation constant pKa of the aqueous self-assembled monolayer removal solution is −4 or more and 14 or less. By setting the acid dissociation constant pKa of the aqueous self-assembled monolayer removal solution to -4 or higher, even when a metal film such as a Cu film or an Al ₂ O ₃ film is provided on the substrate, the aqueous self-assembled monolayer removal solution can be Unnecessary etching of these films by the self-assembled monolayer removal liquid can be prevented or reduced.

According to the present invention, it is possible to provide a substrate processing method and a substrate processing apparatus that can selectively and satisfactorily remove a self-assembled monolayer as a protective film.

2 is a flowchart showing an example of an overall flow of a substrate processing method according to a first embodiment of the present invention. FIG. 2 is a schematic diagram showing an example of a state change of a substrate in the film forming method according to the first embodiment of the present invention, in which (a) the material for forming a self-assembled monolayer is supplied to the substrate surface; The figure (b) shows the formation of a self-assembled monolayer in the metal film formation area on the substrate surface, and the figure (c) shows the formation of a self-assembled monolayer in the metal film non-formation area on the substrate surface. represents the state of being FIG. 1 is a schematic diagram showing an example of a change in state of a substrate in the film formation method according to the first embodiment of the present invention, in which FIG. 1(a) shows a state in which a self-assembled monolayer is irradiated with ultraviolet light, and FIG. 1(b) shows a state in which the self-assembled monolayer is removed from a metal film formation region on the substrate surface. FIG. 2 is an explanatory diagram schematically showing a supply device in the substrate processing apparatus according to the first embodiment of the present invention. FIG. 2 is an explanatory diagram schematically showing a removal device in the substrate processing apparatus according to the first embodiment of the present invention. FIG. 6(a) is a perspective view showing an outline of an ultrasonic nozzle in a removal device according to a first embodiment of the present invention, and FIG. 6(b) is a vertical sectional view showing an outline of the ultrasonic nozzle. 7 is a flowchart showing an example of the overall flow of a substrate processing method according to a second embodiment of the present invention. FIG. 11 is an explanatory view illustrating an outline of a removal device in a substrate processing apparatus according to a second embodiment of the present invention. It is a sectional view showing an outline of a two fluid nozzle in a removal device of a 2nd embodiment of the present invention. 10(a) and 10(b) show graphs illustrating the X-ray photoelectron spectrum on a Cu film.

(First embodiment)
<Substrate processing method>
A substrate processing method according to a first embodiment of the present invention will be described below with reference to FIGS. 1 to 3. FIG. 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. FIGS. 2(a) to 2(c) are schematic diagrams showing an example of changes in the state of the substrate in the film forming method according to the first embodiment of the present invention, in which FIG. 2(a) shows a self-organized This figure shows how the monomolecular film forming material is supplied to the substrate surface. Figure (b) shows how a self-assembled monolayer is formed in the metal film formation area on the substrate surface, and figure (c) shows how the self-assembled monolayer is formed in the metal film formation area on the substrate surface. This figure shows how a film is formed in a region where no metal film is formed on the surface of the substrate. FIGS. 3(a) and 3(b) are schematic diagrams showing an example of a state change of a substrate in the film forming method according to the first embodiment of the present invention, and FIG. 3(a) shows a self-organized This figure shows how the monomolecular film is irradiated with ultraviolet rays, and FIG. 2B shows how the self-assembled monomolecular film in the metal film formation region on the substrate surface has been removed.

The substrate processing method of this embodiment provides a technique for selectively forming a film on the surface of a substrate W depending on the material of the substrate surface. In this specification, "substrate" refers to various substrates such as semiconductor substrates, glass substrates for photomasks, glass substrates for liquid crystal displays, glass substrates for plasma displays, substrates for FEDs (Field Emission Displays), substrates for optical disks, substrates for magnetic disks, and substrates for magneto-optical disks.

As shown in FIG. 1, the substrate processing method of this embodiment includes a substrate W preparation step S101, a self-assembled monolayer forming step S102 for forming a SAM, a film forming step S103, and an ultraviolet ray on the SAM. The method includes at least an ultraviolet irradiation step S104 for irradiating SAM, and a removal step S105 for removing SAM.

As shown in FIGS. 1 and 2(a), the substrate W prepared in the substrate W preparation step S101 has a metal film formation region where the metal film 11 is exposed and an insulating film 12 is exposed. and a metal film non-formation region. More specifically, the substrate W includes, for example, one having an insulating film 12 in which a trench of an arbitrary wiring width is formed, and a metal film 11 embedded in the trench. Note that the step of preparing the substrate W may include, for example, carrying the substrate W into a chamber (details will be described later) that is a container that accommodates the substrate W by a substrate carry-in/out mechanism.

Although one metal film formation region and one metal film non-formation region are formed in FIG. 2A, a plurality of each may be formed. For example, a strip-shaped metal film-free region may be interposed between adjacent strip-shaped metal film-formed regions, and a strip-shaped metal film-free region may be interposed between adjacent strip-shaped metal film-free regions. The regions may be arranged to be interposed.

Furthermore, the substrate W of this embodiment is not limited to a case where only a metal film-formed region and a metal film-non-formed 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 formed and exposed on the surface. In this case, the position at which the region is provided is not particularly limited and can be set arbitrarily.

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

The insulating film 12 is not particularly limited, and may be made of, for example, silicon oxide (SiO ₂ ), hafnium oxide (HfO ₂ ), zirconia (ZrO ₂ ), silicon nitride (SiN), or the like.

The processing liquid used in the SAM formation process S102 contains at least a material for forming a SAM (hereinafter referred to as the "SAM-forming material") 13 and a solvent. The SAM-forming material may be dissolved or dispersed in the solvent.

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

The monophosphonic acid is not particularly limited, and examples thereof include phosphonic acid compounds represented by the general formula R-P(=O)(OH) ₂ (wherein R represents an alkyl group having 1 to 18 carbon atoms; an alkyl group having 1 to 18 carbon atoms and containing a fluorine atom; or a vinyl group). In this specification, when a range of carbon numbers is expressed, it is meant that the range includes all integer carbon numbers included in the range. Thus, for example, an alkyl group having "1 to 3 carbon atoms" means all alkyl groups having 1, 2, and 3 carbon atoms.

The alkyl group having 1 to 18 carbon atoms may be either linear or branched. Furthermore, the number of carbon atoms in the alkyl group is preferably in the range of 10 to 18, more preferably in the range of 14 to 18. Further, the alkyl group having a carbon number of 1 to 18 and having a fluorine atom may be either linear or branched. Furthermore, the number of carbon atoms in the alkyl group having a fluorine atom is preferably in the range of 10 to 18, more preferably in the range of 14 to 18.

Further, specific examples of the monophosphonic acid represented by RP(=O)(OH) ₂ include compounds represented by any of the following chemical formulas (1) to (16). .

Furthermore, as the monophosphonic acid, in addition to those exemplified above, compounds represented by any of the following chemical formulas (17) to (19) can also be used.

Examples of the diphosphonic acid include compounds represented by either of the following chemical formulas (20) and (21).

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

The solvent in the treatment liquid is not particularly limited, and examples thereof include alcohol solvents, ether solvents, glycol ether solvents, glycol ester solvents, and the like. The alcohol solvent is not particularly limited and includes, for example, ethanol. The ether solvent is not particularly limited, and examples thereof 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 combination of two or more. Furthermore, these solvents can be used in any combination with the phosphonic acid compounds listed above. Among the exemplified solvents, from the viewpoint of being able to dissolve the phosphonic acid compound, alcohol solvents are preferred, and ethanol is particularly preferred.

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

Further, the treatment liquid may contain known additives within a range that does not impede the effects of the present invention. The additives are not particularly limited, and include, for example, stabilizers, surfactants, and the like.

In the SAM forming step S102, as shown in FIGS. 1, 2(a) and 2(b), a processing liquid is brought into contact with the surface of the substrate W, and a SAM contained in the processing liquid is formed on the surface of the metal film 11. This is a step of forming the SAM 14 by adsorbing the material 13. Here, the SAM 14 is selectively formed only on the metal film 11 in the metal film formation region of the substrate W, and is not formed on the metal film non-formation region. For example, when the metal film 11 is a Cu (copper) film, the SAM 14 is formed only on the metal film 11 because of the phosphonic acid group of the phosphonic acid compound that is the SAM forming material 13 and the -OH on the surface of the Cu film. This is because the groups react as shown in the following chemical reaction formula.

The method of bringing the treatment liquid into contact with the substrate W is not particularly limited, and includes, for example, a method of applying the treatment liquid to the surface of the substrate W, a method of spraying the treatment liquid onto the surface of the substrate W, and a method of immersing the substrate W in the treatment liquid. For example, the method of

One method for applying the processing liquid to the surface of the substrate W is, for example, to supply the processing liquid to the center of the surface of the substrate W while the substrate W is rotated at a constant speed around its center as an axis. As a result, the processing liquid supplied to the surface of the substrate W flows from near the center of the surface of the substrate W toward the peripheral edge of the substrate W due to the centrifugal force generated by the rotation of the substrate W, and is spread over the entire surface of the substrate W. As a result, the entire surface of the substrate W is covered with the processing liquid, and a liquid film of the processing liquid is formed.

The SAM forming step S102 can be performed, for example, in an inert gas atmosphere.

The SAM formation process S102 may include a process of removing the processing liquid remaining on the surface of the substrate W. The process of removing the processing liquid is not particularly limited, and may include, for example, a process of spinning off the processing liquid by centrifugal force by rotating the substrate W at a constant speed.

Further, when performing the step of shaking off the processing liquid by centrifugal force, the rotation speed of the substrate W is not particularly limited as long as it can sufficiently shake off the processing liquid, but it is usually set in the range of 800 rpm to 2500 rpm, and preferably The speed is 1000 rpm to 2000 rpm, more preferably 1200 rpm to 1500 rpm.

The film forming step S103 is a step of forming a target film 15 on the insulating film 12 in the area where the metal film is not formed, as shown in FIGS. 1 and 2(c). At this time, the SAM 14 formed in the metal film formation region serves as a masking function as a protective film for the metal film 11. Thereby, the desired film 15 can be selectively formed in the region where the metal film is not formed.

The target film 15 is not particularly limited, and examples include films made of aluminum oxide (Al ₂ O ₃ ), cobalt oxide (CoO), zirconium oxide (ZrO ₂ ), or the like. The method for forming these films 15 is not particularly limited, and includes, for example, CVD (Chemical Vapor Deposition), ALD (Atomic Layer Deposition), vacuum evaporation, sputtering, and plating. , thermal CVD, thermal ALD, and the like.

The ultraviolet irradiation step S104 is a step of irradiating the SAM 14 with ultraviolet rays to reduce the water repellency of the SAM 14, as shown in FIGS. 1 and 3(a).

This step is performed with at least the surface of the substrate W under an atmosphere containing oxygen atoms. For example, when ultraviolet rays are irradiated in an atmosphere containing oxygen (O ₂ ) and/or moisture (including the atmosphere), active oxygen species such as oxygen atoms, ozone, and OH radicals can be generated. When this active oxygen species comes into contact with the self-assembled monolayer, it can cleave the bonding portions such as linear chains of the monomolecules (organic composition) forming the self-assembled monolayer. Thereby, the water repellency of the surface of the self-assembled monolayer can be reduced and the surface can be modified. Further, this step may be performed in the presence or supply of active oxygen species such as oxygen atoms, ozone, and OH radicals.

The wavelength range of the ultraviolet rays to be irradiated is not particularly limited as long as it is 380 nm or less, but it is preferably 254 nm or less from the viewpoint of promoting a decrease in the water repellency of the surface of the SAM 14.

The irradiation intensity of ultraviolet rays is preferably 1 mW/cm ² or more and 50 mW/cm ² or less, more preferably 3 mW/cm ² or more and 30 mW/cm ² or less, and 5 mW/cm ² or more and 20 mW/cm 2 or less. It is particularly preferable that it is ² or less. By setting the ultraviolet irradiation intensity to 1 mW/cm ² or more, it is possible to reduce the water repellency of the surface of the SAM 14 and maintain good wettability of the aqueous self-assembled monolayer removal solution to the SAM 14, which will be described later.

The ultraviolet irradiation time is preferably 1 minute or more and 60 minutes or less, more preferably 5 minutes or more and 30 minutes or less, particularly preferably 10 minutes or more and 20 minutes or less. By setting the ultraviolet ray irradiation time to 1 minute or longer, the water repellency of the surface of the SAM 14 can be reduced, and the wettability of the aqueous self-assembled monolayer removal solution, which will be described later, to the SAM 14 can be maintained satisfactorily.

The number of times that ultraviolet light is irradiated is not particularly limited, but it is preferable to irradiate the film with ultraviolet light once. This can prevent or reduce damage to the film 15, etc.

The contact angle (23°C) of the SAM14 surface after UV irradiation with DIW (deionized water) is preferably 0° or more and 40° or less, more preferably 0° or more and 30° or less, and particularly preferably 0° or more and 20° or less. If the contact angle is 40° or less, the wettability with the removal liquid can be well maintained. As a result, the selective removal of the SAM14 can be well performed. The method for measuring the contact angle is not particularly limited, and for example, the method described below can be adopted.

The removal step S105 is a step of removing the SAM 14 formed in the metal film forming region after the step of forming the film 15 is performed, as shown in FIGS. 1 and 3(b). In this step, the SAM 14 is removed 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 the SAM 14 is modified to reduce water repellency in the ultraviolet irradiation step S104, the wettability of the removal liquid to the SAM 14 is improved. Therefore, the SAM 14 can be more effectively dissolved by the removal liquid. Further, since the removal liquid is given ultrasonic vibration, when it comes into contact with the SAM 14, the ultrasonic vibration can be propagated to the SAM 14. As a result, the permeability of the removal liquid to the SAM 14 can be improved, and the separation of the SAM 14 from the substrate W can be promoted. Thereby, in this step, as shown in FIG. 3(b), it is possible to obtain a substrate W in which the film 15 is selectively formed only in the region where the metal film is not formed and the metal film 11 is exposed. Here, the term "removal of the SAM 14" includes the case where the SAM 14 is removed by dissolving it in a removal liquid, as well as the case where the SAM 14 is detached (separated) from the substrate W.

The removal liquid is not particularly limited as long as it is aqueous and can selectively remove SAM14. Since the removal liquid is aqueous, it can exhibit good wettability to the surface of SAM14 that has been surface-modified to reduce water repellency. In this specification, "aqueous" means having a liquid composition that can be diluted with water or a liquid composition that contains water. Specific examples of removal liquids include organic acids such as maleic acid, methylphosphonic acid, and acetic acid, and hydrochloric acid. The removal liquid may also contain an aqueous solvent. Examples of aqueous solvents include water.

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, based on the total mass of the removal solution.

The acid dissociation constant pKa of the remover is preferably -4 to 14, more preferably 0 to 10, and particularly preferably 1.96 to 4.76. By using a remover having a pKa of -4 or more, it is possible to prevent or reduce unnecessary etching of the metal film 11 such as a Cu film and the film 15 such as an Al ₂ O ₃ film by the remover.

The method of bringing the removal liquid into contact with the SAM 14 is not particularly limited, and examples include a method of applying the removal liquid to the surface of the substrate W, a method of spraying the removal liquid onto the surface of the substrate W, and a method of immersing the substrate W in the removal liquid. Examples include methods.

One method for applying the removal liquid to the surface of the substrate W is, for example, to supply the removal liquid to the center of the surface of the substrate W while the substrate W is rotated at a constant speed around its center as an axis. As a result, the removal liquid supplied to the surface of the substrate W flows from near the center of the surface of the substrate W toward the peripheral edge of the substrate W due to the centrifugal force generated by the rotation of the substrate W, and is spread over the entire surface of the substrate W. As a result, the entire surface of the substrate W is covered with the removal liquid, and a liquid film of the removal liquid is formed.

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

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

Further, when performing the step of shaking off the removal liquid by centrifugal force, the rotation speed of the substrate W is not particularly limited as long as it can sufficiently shake off the removal liquid, but it is usually set in the range of 800 rpm to 2500 rpm, and preferably The speed is 1000 rpm to 2000 rpm, more preferably 1200 rpm to 1500 rpm.

As described above, according to the substrate processing method of the present embodiment, ultraviolet rays are irradiated in advance before the SAM 14 removal step S105 to reduce the water repellency of the SAM 14, so that the surface of the SAM 14 is well wetted with the removal liquid. be able to. In addition, since the removal liquid is given ultrasonic vibration as a physical effect, when the removal liquid comes into contact with the SAM 14, the ultrasonic vibration is propagated to improve the permeability of the removal liquid into the SAM 14. Peeling of the SAM 14 from the substrate W can be promoted. As a result, the substrate processing method of this embodiment can selectively remove the SAM 14 better than conventional substrate processing methods.

<Substrate Processing Apparatus>
Next, the substrate processing apparatus according to the first embodiment will be described with reference to Figs. 4 to 6. Fig. 4 is an explanatory diagram showing a removal liquid supply device in the substrate processing apparatus of this embodiment. Fig. 5 is an explanatory diagram showing a removal device in the substrate processing apparatus of this embodiment. Fig. 6(a) is a perspective view showing an outline of an ultrasonic nozzle in the removal device of this embodiment, and Fig. 6(b) is a vertical cross-sectional view showing an outline of the ultrasonic nozzle.

As shown in FIGS. 4 and 5, the substrate processing apparatus of this embodiment includes a supply apparatus 100 for supplying a removal liquid, a removal apparatus 200 for removing the SAM 14, and a control system for controlling each part of the substrate processing apparatus. and a control unit 300 for the purpose.

[Feeding device]
As shown in FIG. 4, the supply device 100 according to the present embodiment has a function of supplying the removal liquid to the removal device 200, and includes at least a removal liquid tank 111, a pressurizing section 112, and a pipe 113. Be prepared.

The removal liquid tank 111 may include an agitation unit that agitates the treatment liquid in the removal liquid tank 111, and a temperature adjustment unit that adjusts the temperature of the treatment liquid in the removal liquid tank 111 (neither is shown). Examples of the agitation unit include a rotation unit that agitates the removal liquid in the removal liquid tank 111, and an agitation control unit that controls the rotation of the rotation unit. The agitation control unit is electrically connected to the control unit 300, and the rotation unit is equipped with, for example, a propeller-shaped agitation blade at the lower end of the rotation shaft. The control unit 300 issues an operation command to the agitation control unit to rotate the rotation unit, thereby agitating the removal liquid with the agitation blade. As a result, the concentration and temperature of the removal liquid can be made uniform in the removal liquid tank 111.

The pressurizing unit 112 includes a nitrogen gas supply source 116, which is a gas supply source for pressurizing 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 connected to the removal liquid tank 111 by the nitrogen gas supply pipe 114. An air pressure sensor (not shown) electrically connected to the control unit 300 can be provided in the removal liquid tank 111. In this case, the control unit 300 can maintain the air pressure in the removal liquid tank 111 at a predetermined air pressure higher than atmospheric pressure by controlling the operation of the pump based on the value detected by the air pressure sensor. In addition, the valve 115 can be electrically connected to the control unit 300, so that the opening and closing of the valve 115 can be controlled by the operation command of the control unit 300.

The pipe 113 is connected to the removal device 200 via a pipeline. A valve 113a is provided midway along the pipe 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 an operation command from the control unit 300. When the valves 113a and 115 are opened by an operation command from the control unit 300, the processing liquid is supplied (pressurized) to the removal device 200 via the pipe 113.

[Removal device]
Next, the removal device 200 will be described with reference to FIG.
The removal apparatus 200 according to this embodiment is a single-wafer type removal apparatus capable of removing the SAM 14 formed on the metal film 11 .

5, the removal device 200 includes at least a substrate holder 210 for holding the substrate W, a supply unit 220 for supplying the removal liquid to the surface Wf of the substrate W, a chamber 230 which is a container for accommodating the substrate W, a splash prevention cup 240 for collecting the removal liquid, and an ultraviolet ray irradiation unit 250. The removal device 200 may also include a loading/unloading means (not shown) for loading and unloading the substrate W.

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

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

A number of chuck pins 216 for gripping the peripheral edge of the substrate W are erected near the peripheral edge of the spin base 212. There is no particular limit to the number of chuck pins 216 to be installed, but it is preferable to provide at least three or more in order to securely hold the circular substrate W. In this embodiment, three chuck pins 216 are arranged at equal intervals along the peripheral edge 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 holds the substrate W by pressing against the outer peripheral end face of the substrate W supported by the substrate support pin.

The supply unit 220 is disposed above the substrate holding unit 210 and supplies the removal liquid supplied from the supply device 100 onto the front surface Wf of the substrate W. The supply section 220 includes an ultrasonic wave applying section and an arm 222, as shown in FIGS. 5, 6(a), and 6(b).

The ultrasonic application unit includes 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 placed above the spin base 212 when discharging the removal liquid. The ultrasonic nozzle 221 has a body 221a and a nozzle tip 221b provided at the lower part of the body 221a, and has a cylindrical shape with a lid as a whole.

The ultrasonic nozzle 221 has a filling space FS in which the removal liquid can be filled. The nozzle tip 221b tapers downward, and has a substantially V-shape in longitudinal section, as shown in FIG. 6(b). 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 a cross section (a cross section substantially perpendicular to the treatment liquid discharge direction) of the body portion 221a. Therefore, the cross-sectional area of the nozzle tip 221b gradually decreases in diameter from the top (the cross-section of the body 221a) toward the bottom (the 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 surface of the body portion 221a. The supply port 224 is in communication with the piping 113 of the supply device 100 .

As shown in FIG. 6B, the ultrasonic nozzle 221 is provided with an ultrasonic vibrator 225 inside the body 221a. The ultrasonic vibrator 225 is provided on the upper wall surface of the body 221a so as to face the discharge port 228. The ultrasonic vibrator 225 is electrically connected to a cable 226, which is electrically connected to an ultrasonic oscillator. The ultrasonic oscillator is further electrically connected to the control unit 300, and causes the ultrasonic vibrator 225 to emit ultrasonic waves in response to an operation command from the control unit 300, thereby applying ultrasonic vibrations to the removal liquid in the filling space FS. This generates cavitation in the removal liquid, generating tiny bubbles. A thin plate of quartz or high-purity SiC (silicon carbide) is attached to the surface of the ultrasonic vibrator 225. The ultrasonic nozzle 221 is made of PTFE (polytetrafluoroethylene) or quartz for chemical resistance, but the body 221a may be made of PTFE and the nozzle tip 221b (or only the area around the outlet 228) may be made of quartz.

Furthermore, the ultrasonic nozzle 221 is provided with a plurality of plate-like members 227 below the ultrasonic vibrator 225 inside the body 221a. The plurality of plate-like members 227 are preferably provided so as not to impede the flow of the removal liquid. In FIG. 6(b), the plurality of plate-like members 227 are provided at equal intervals from one another and arranged substantially parallel to the ejection direction P of the removal liquid. By providing the plate-like members 227, the amount of bubbles caused by cavitation generated in the removal liquid can be increased. Note that the plate-like members 227 are preferably made of a material having chemical resistance, similar to the ultrasonic nozzle 221.

Further, the supply section 220 further includes a supply section elevating mechanism 223, as shown in FIG. The supply section lifting mechanism 223 is connected to the arm 222.

The supply unit lifting mechanism 223 is electrically connected to the control unit 300 and can raise and lower the supply unit 220 in response to an operation command from the control unit 300. This allows the ultrasonic nozzle 221 of the supply unit 220 to be moved closer to or farther away from the substrate W held by the substrate holding unit 210, thereby adjusting the distance between the surface Wf of the substrate W.

When the substrate W is to be loaded or unloaded into the removal device 200, the control unit 300 issues an operational command to operate the supply unit lifting mechanism 223 and raise the supply unit 220. This allows the ultrasonic nozzle 221 and the surface Wf of the substrate W to be spaced a fixed distance apart, making it easier to load or unload the substrate W.

The anti-scattering cup 240 is provided to surround the spin base 212. The anti-scattering cup 240 is connected to an elevating drive mechanism (not shown) and can be moved up and down in the vertical direction. When supplying the removal liquid to the surface Wf of the substrate W, the anti-scattering cup 240 is positioned at a predetermined position by the elevating drive mechanism and surrounds the substrate W held by the chuck pins 216 from a lateral position. Thereby, the removal liquid scattered from the substrate W and the spin base 212 can be collected.

The ultraviolet ray irradiation unit 250 is disposed inside the removal apparatus 200 above the substrate holding unit 210 (in the direction indicated by the arrow Z in FIG. 5 ) so as to be able to irradiate ultraviolet rays onto the surface Wf of the substrate W held by the substrate holding unit 210. The ultraviolet ray irradiation unit 250 includes at least a plurality of light source units 251 and quartz glass 252.

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

The type of light source unit 251 is not particularly limited as long as it irradiates ultraviolet light, and may include other radiation or wavelength ranges other than the ultraviolet region. Specific examples of the light source unit 251 that can be used include a low-pressure mercury lamp (dominant wavelength: 185 nm, 254 nm), a high-pressure mercury lamp (dominant wavelength: 365 nm), an excimer UV lamp (dominant wavelength: 272 nm), a metal halide lamp (250 to 450 nm), and a UV (ultraviolet)-LED (Light Emitting Diode). In addition, the multiple light source units 251 may be of the same type or different types. When multiple different types of light source units 251 are used, they can be arranged with different peak wavelengths, light intensities, etc.

The quartz glass 252 is disposed between the light source unit 251 and the substrate W. The quartz glass 252 is a plate-like body, and is arranged so as to be parallel to the horizontal direction. The quartz glass 252 is also optically transparent to ultraviolet light, heat-resistant, and corrosion-resistant, and allows the ultraviolet light irradiated from the light source unit 251 to pass through, enabling it to be irradiated onto the surface Wf of the substrate W. Furthermore, the quartz glass 252 can protect the light source unit 251 from the atmosphere in the chamber 253.

In the above explanation, an example has been given of a case where the removal device in the substrate processing apparatus of the present invention is a single-wafer type that processes substrates W one by one. However, the substrate processing apparatus of the present invention is not limited to this form, and can also be applied to another form of the substrate processing apparatus of the present invention, where the removal device is a batch type that processes multiple substrates at once.

[Control unit]
The control section 300 is electrically connected to each section of the substrate processing apparatus and controls the operation of each section. The control unit 300 is configured by a computer having a calculation unit and a storage unit. As the calculation unit, a CPU is used that performs various calculation processes. The storage unit also includes a ROM that is a read-only memory that stores a substrate processing program, a RAM that is a readable and writable memory that stores various information, and a magnetic disk that stores control software, data, and the like. Data regarding substrate processing conditions is stored in advance on the magnetic disk. The substrate processing conditions include, for example, driving conditions for driving an ultrasonic oscillator, irradiation conditions for ultraviolet irradiation, conditions for supplying a removal liquid to the substrate W, and the like. The CPU reads the substrate processing conditions into the RAM and controls each part of the substrate processing apparatus according to the contents.

(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 FIG. FIG. 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.

As shown in FIG. 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 vibrations to the removal liquid, a gas is brought into contact with the removal liquid to generate droplets of the removal liquid, and the droplets of the removal liquid are used to selectively remove the SAM 14. Even with this configuration, the selective removal of the SAM 14 can be performed well. In the following, the steps of the substrate W preparation step S101, the self-assembled monolayer formation step S102, the film formation step S103, and the ultraviolet ray irradiation step S104 shown in FIG. 7 are the same as those of the first embodiment, so detailed descriptions of them will be omitted.

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 the gas, and this mixed fluid is injected and supplied toward the surface of the substrate W. . The mixed fluid contains minute droplets of removal liquid. The droplets of the removal liquid ride on the gas flow and collide with the surface of the substrate W. This collision applies an impact to the SAM 14 and promotes the separation of the SAM 14 from the surface of the substrate W.

The gas to be mixed with the removal liquid is not particularly limited, and examples thereof include inert gases such as nitrogen gas. By using an inert gas, deterioration of the removal liquid can be prevented. Note that the removal step S105' can be performed, for example, under an inert gas atmosphere.

The type of removal solution, the concentration of the organic acid contained in the removal solution, the acid dissociation constant pKa, and the like are the same as those described in the first embodiment. The method of removing the removal solution is also the same as that described in the first embodiment. Therefore, the description of these is omitted.

<Substrate processing equipment>
Next, a substrate processing apparatus according to a second embodiment will be described based on FIGS. 8 and 9. FIG. 8 is an explanatory diagram showing an outline of the removal device in the substrate processing apparatus of this embodiment. FIG. 9 is a cross-sectional view schematically showing a two-fluid nozzle in the substrate processing apparatus of this embodiment.

The substrate processing apparatus of this embodiment differs mainly in that, as shown in FIG. 8, a droplet supply section 260 is used as a supply section in the removal apparatus 200'. As the supply device of this embodiment, one having basically the same configuration as that of the first embodiment can be used (see FIGS. 4 and 5). Therefore, the description thereof will be omitted by giving the same reference numerals.

The droplet supply unit 260 is disposed 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. The droplet supply unit 260 includes a two-fluid nozzle 261 and an arm 274, as shown in FIGS. 8 and 9.

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

Both the outer cylinder 262 and the inner cylinder 263 have a cylindrical outer shape, and are coaxially arranged so as to share the central axis L. Further, the lower end surface 262a of the outer cylinder 262 is a ring-shaped surface perpendicular to the central axis L. The two-fluid nozzle 261 is configured such that its 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) when ejecting droplets of the removal liquid. ) are placed opposite each other.

The inner cylinder 263 has an internal space 264 formed along the central axis L so as to be cylindrical. 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 to the piping 113 of the supply device 100 by a pipeline. The removal liquid supplied from the supply device 100 through the piping 113 flows into the internal space 264 and is discharged (discharged downward along the central axis L) from the opening 265 at the lower end. In other words, the internal space 264 functions as a flow path for the removal liquid, and the opening 265 functions as an outlet for the removal liquid. Hereinafter, the internal space 264 is also referred to as the "removal liquid flow path 264". The opening 265 at the lower end of the internal space 264 is also referred to as the "removal liquid outlet 265".

The inner cylinder 263 includes a large diameter portion 263a and a small diameter portion 263b provided continuously 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 tube 262 fitted outside the inner tube 263 is equal to the outer diameter of the large diameter portion 263a, and the outer tube 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 space with a ring-shaped cross section centered on the central axis L, and opens in a ring-shape (that is, a ring-shape surrounding the removal liquid discharge port 265) at the lower end of the outer cylinder 262.

One end of an introduction pipe 267 that penetrates the inner and outer surfaces of the outer cylinder 262 is connected to the upper end of the gap 266. The other end of the introduction pipe 267 is connected to a pipe 273a (described later) that is connected to a gas supply source 273. Gas supplied from the gas supply source 273 via the pipe 273a and the introduction pipe 267 flows into the gap 266 and is discharged from an 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. In the following, the gap 266 is also referred to as the "gas flow path 266". The opening 268 at the lower end of the gap 266 is also referred to as the "gas discharge port 268".

A flange 269 is formed near the lower end of the small diameter portion 263b and extends radially outward from its outer peripheral surface. A through hole 270 is formed in the flange 269, and the gas flowing into the gas flow path 266 is changed in flow direction when passing through the through hole 270, and flows around the central axis L. It flows as a swirling flow.

In the small diameter portion 263b, below the portion where the flange 269 is formed, a cylindrical short tube portion 271 is formed that protrudes from the lower surface of the flange 269 along the central axis L. The short tube portion 271 is arranged so that its central axis coincides with the central axis L. The outer diameter of the short tube portion 271 is smaller than the inner edge diameter of the lower end surface 262a of the outer tube 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 tube portion 271 and the lower end surface 262a of the outer tube 262.

A portion of the inner wall surface of the outer tube 262 surrounding the short tube portion 271 is formed into a reduced diameter shape whose inner diameter decreases as it goes downward. Therefore, the swirling flow of gas that has flowed into the space 272 around the short cylindrical 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 discharge port 268. . The spiral airflow discharged from the gas discharge port 268 flows to surround the removal liquid discharged from the removal liquid discharge port 265 along the central axis L, and converges at a certain convergence point F on the central axis L. Proceed as follows. Then, at and around the convergence point F, the removal liquid and the gas collide and mix, forming droplet-shaped removal liquid. Further, the generated droplet-shaped removal liquid is accelerated by the gas flow and becomes a jet stream.

Further, the droplet supply section 260 further includes a droplet supply section elevating mechanism 223'. The droplet supply section lifting mechanism 223' is connected to the arm 274.

The droplet supply unit lifting mechanism 223' is electrically connected to the control unit 300' and can raise and lower the droplet supply unit 260 in response to an operation command from the control unit 300'. This allows the two-fluid nozzle 261 of the droplet supply unit 260 to be moved closer to or farther away from the substrate W held by the substrate holding unit 210, thereby adjusting the distance between the two-fluid nozzle 261 and the surface Wf of the substrate W.

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

The valve 273b is electrically connected to the control unit 300', and the opening and closing of the valve 273b can be controlled by the operation command of the control unit 300'. In addition, the opening and closing of the valve 113a of the supply device 100 that supplies the removal liquid is also controlled by the operation command of the control unit 300'. Therefore, the ejection mode of the removal liquid ejected from the two-fluid nozzle 261 (specifically, the ejection start timing, ejection end timing, type of ejected droplets, ejection flow rate, momentum of the ejected droplets, etc.) can be controlled by the control unit 300'.

In this embodiment, the two-fluid nozzle 261 is an external mixing type two-fluid nozzle. However, the present invention is not limited to this embodiment. For example, it is also possible to use an internal mixing type two-fluid nozzle that generates droplet-shaped removal liquid by colliding gas with the removal liquid within the casing.

[Control unit]
As in the case of the first embodiment, the control section 300' is configured by a computer having a calculation section and a storage section. The magnetic disk of the storage unit includes supply conditions for supplying droplets of the removal liquid to the substrate W in addition to irradiation conditions for ultraviolet irradiation. Further, as in the first embodiment, the CPU used in the calculation section reads the substrate processing conditions into the RAM and controls each section of the substrate processing apparatus according to the contents.

(Other matters)
The supply device and removal device of this embodiment may be used in various devices other than the substrate processing device, or may be used alone.
In the above description, the most preferred embodiment of the present invention has been described. However, the present invention is not limited to this embodiment. Each configuration in the above-described embodiment and each modification can be changed, modified, replaced, added, deleted, and combined within a mutually consistent range. For example, in each embodiment, a method has been described in which the SAM is removed by applying ultrasonic vibration to the removal liquid or by spraying the removal liquid in droplets onto the SAM surface. However, the present invention is not limited to this embodiment. The present invention may be any method as long as the SAM is irradiated with at least ultraviolet rays to reduce its water repellency before the SAM removal step.

The following is a detailed description of preferred embodiments of the present invention. However, unless otherwise specified, the materials, amounts, conditions, etc. described in the embodiments do not limit the scope of the present invention.

Example 1
[Substrate preparation process]
First, a substrate was prepared on whose surface a Cu film (thickness: 100 nm, metal film forming region) was formed as a metal film.

[Formation of SAM and Al ₂ O ₃ film]
Octadecylphosphonic acid ( _CH3 ( _CH2 ) _17P (=O)(OH) ₂ ) (pKa=2.1, pH=3.0) as a SAM forming material was dissolved in an ethanol solvent to prepare a treatment solution. did. The concentration of octadecylphosphonic acid was 0.05% by mass based on the total mass of the treatment liquid.

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

Furthermore, an Al ₂ O ₃ film (film thickness: 5 nm) was formed on the surface of the substrate. Specifically, an Al ₂ O ₃ film was formed by an ALD method using an atomic layer deposition apparatus (trade name: SUNALE-R, manufactured by PICOSUN Corporation).

[Ultraviolet ray irradiation process]
Next, the surface of the SAM was irradiated with ultraviolet light to modify the surface so as to reduce the water repellency of the surface of the SAM. The ultraviolet light irradiation conditions were as follows:
Light source of ultraviolet irradiation part: low pressure mercury lamp (product name: EUV200WS-51, manufactured by Sen Special Light Sources Co., Ltd.)
Ultraviolet peak wavelength: 185 nm, 254 nm
UV irradiation intensity: 10mW/ ^cm2
UV irradiation time: 0.25 hours Pressure in chamber: atmospheric pressure Temperature in chamber: 25°C
Chamber atmosphere: air

[Removal of SAM]
Next, the SAM was removed from the substrate on which the Al ₂ O ₃ film was formed. Specifically, the substrate was immersed in an aqueous solution of acetic acid (pKa=4.76, pH=2.7) with a concentration of 1% by mass to selectively remove the SAM. In this way, a sample according to this example was produced.

(Comparative Example 1)
In this comparative example, after _{the Al2O3} film was formed, the SAM removal process was performed without performing the ultraviolet ray irradiation process. Otherwise, a sample according to this comparative example was produced in the same manner as in Example 1.

(Comparative Example 2)
In this comparative example, instead of the 1% by mass aqueous solution of acetic acid, a mixed solution of hydrochloric acid, IPA (isopropyl alcohol) and DIW was used as the removal solution in a mass ratio of _hydrochloric acid:IPA:DIW=1:50:50. In addition, after the formation of the _Al2O3 film, the SAM removal process was performed without performing the ultraviolet irradiation process. Otherwise, the sample according to this comparative example was prepared in the same manner as in Example 1.

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

As can be seen from FIGS. 10(a) and 10(b), in each of the substrates of Example 1 and Comparative Examples 1 and 2, the peak is strongest at the bond energy value specific to Cu atoms on the Cu film. Appeared. Furthermore, in each of the substrates of Comparative Examples 1 and 2, a peak appeared in the bond energy value specific to the Al atom. This confirmed that in Comparative Examples 1 and 2, the Al atoms remaining in the SAM during the formation of the Al ₂ O ₃ film remained even after the SAM removal step. As a result, it was estimated that in these comparative examples, SAM was not removed well from the Cu film and remained. On the other hand, in Example 1, no peak appeared in the bond energy value specific to Al atoms. This confirmed that in Example 1, SAM was selectively removed from the Cu film.

(Contact angle measurement)
The contact angle of DIW on the surface of the Cu film was measured under the following conditions using a DIW (trade name: DMo-701, manufactured by Kyowa Interface Science Co., Ltd.). The measurement was performed at five different locations, and the average value was calculated as the contact angle. The results are shown in Table 1.
Measurement atmosphere: 23°C, 50% RH
Drop volume: 2 μL
Time from droplet application to measurement: 1 second

(Example 2)
In this example, an aqueous maleic acid solution (pKa=1.96, pH=1.3) with a concentration of 10% by mass was used as the removal liquid instead of an aqueous acetic acid solution with a concentration of 1% by mass. A sample according to this example was produced in the same manner as in Example 1 except for the above.

(Example 3)
In this example, an aqueous maleic acid solution (pKa=1.96, pH=1.3) with a concentration of 10% by mass was used as the removal liquid instead of an aqueous acetic acid solution with a concentration of 1% by mass. Further, in the removal step, when the substrate was immersed in the maleic acid aqueous solution, ultrasonic vibration was applied to the maleic acid aqueous solution to selectively remove the SAM. A sample according to this example was produced in the same manner as in Example 1 except for the above.

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

(Example 5)
In this example, as the removal liquid, an aqueous methylphosphonic acid solution (pKa=2.36, pH=1.1) with a concentration of 10% by mass was used instead of an aqueous acetic acid solution with a concentration of 1% by mass. Further, in the removal step, when the substrate was immersed in the methylphosphonic acid aqueous solution, ultrasonic vibration was applied to the methylphosphonic acid aqueous solution to selectively remove the SAM. A sample according to this example was produced in the same manner as in Example 1 except for the above.

(Example 6)
In this example, instead of the 1% acetic acid aqueous solution, a 100% acetic acid aqueous solution (pKa=4.76) was used as the remover. A sample according to this example was prepared in the same manner as in Example 1.

(Example 7)
In this example, acetic acid having a concentration of 100% by mass (pKa=4.76) was used as the removal liquid instead of an aqueous acetic acid solution having a concentration of 1% by mass. Further, in the removal process, when the substrate was immersed in acetic acid, ultrasonic vibration was applied to the acetic acid to selectively remove the SAM. A sample according to this example was produced in the same manner as in Example 1 except for the above.

(Evaluation of removal performance)
The SAM removal performance of each sample in Examples 2 to 7 was evaluated based on the residual ratio of Al atoms on the Cu film.
That is, for each sample, the cross-section of each sample was observed with a transmission electron microscope (TEM), and the elemental analysis of the observed area was performed with energy _dispersive X-ray spectroscopy (EDX). The elemental analysis by EDX was performed on the Al atoms in the _Al2O3 film and the Cu film. Furthermore, the residual ratio of Al atoms on the Cu film was calculated based on the following formula. The results are shown in Table 2.
(Residual ratio of Al atoms)=(Amount of Al atoms on _Cu film)/(Amount of Al atoms in _Al2O3 film)×100(%)

It was confirmed that in any of the samples of Examples 2 to 7, the residual ratio of Al atoms could be suppressed. In particular, in Examples 3, 5, and 7 in which SAM was removed by applying ultrasonic vibration to the removal solution, the residual ratio of Al atoms could be suppressed to 10% or less in all cases. Al atoms remain in the SAM due to the formation of the Al ₂ O ₃ film. Therefore, it can be said that the less Al atoms remain in the Cu film after SAM removal, the better the SAM is selectively removed from the Cu film. In each of the samples of Examples 2 to 7, the residual ratio of Al atoms on the Cu film was suppressed, and especially in Examples 3, 5, and 7, the residual ratio of Al atoms was suppressed well. It can be said that all of the removal solutions used in Examples 2 to 7 are excellent in removing SAM.

Furthermore, in each of the samples of Examples 2 to 7, it was also confirmed to what extent the etching of the Cu film and the Al ₂ O ₃ film was suppressed before and after the removal of the SAM. Specifically, the film thicknesses of the Cu film and the Al ₂ O ₃ film before and after the removal of the SAM were measured by TEM observation, and the amount of decrease in the film thickness of the Cu film and the Al ₂ O ₃ film was calculated. The results are shown in Table 2. As can be seen from Table 2, in all of the samples of Examples 2 to 7, it was possible to suppress the amount of decrease in the film thickness of the Cu film and the Al ₂ O ₃ film. In particular, in Examples 2, 3, 6, and 7, the reduction in the thickness of the Al ₂ O ₃ film was able to be suppressed to 0.5 nm or less compared to the initial film thickness of 5 nm. Furthermore, in Example 7, the amount of decrease in the thickness of the Cu film could be suppressed to 3 nm or less compared to the initial thickness of 100 nm. As a result, in each sample of Examples 2 to 7, etching of the Cu film and Al ₂ O ₃ film was suppressed, and in particular, in Examples 2, 3, 6, and 7, etching of the Al ₂ O ₃ film was suppressed. Since the etching of the Cu film was well suppressed in Example 7, it can be said that the substrate processing methods of Examples 2 to 7 are all excellent in selectively removing SAM.

11... Metal film 12... Insulating film 13... Self-assembled monolayer (SAM) forming material 14... Self-assembled monolayer (SAM)
15...film 100...supply device 111...removal liquid tank 114...nitrogen gas supply pipe 116...nitrogen gas supply source 200...removal device 210...substrate holder 211...spin chuck 212...spin base 213...rotation support 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 section lifting mechanism 223'...droplet supply section lifting mechanism 2 24...Supply port 225...Ultrasonic vibrator 228...Discharge port 240...Shatterproof cup 250...UV irradiation section 251...Light source section 252...Quartz glass 253...Chamber 260...Droplet supply section 261...Two-fluid nozzle 273...Gas supply source 273a...Pipe 273b...Valve 300...Control section S101...Preparation step S102...Self-assembled monolayer (SAM) formation step S103...Film formation step S104...UV irradiation step S105...Removal step W...Substrate Wf...Surface of substrate

Claims (13)

A substrate processing method for processing a substrate having a self-assembled monolayer formed on a surface thereof, comprising the steps of:
an ultraviolet irradiation step of irradiating the self-assembled monolayer with ultraviolet light in an atmosphere containing oxygen atoms to reduce the water repellency of the surface of the self-assembled monolayer;
a removing step of contacting the self-assembled monolayer after the ultraviolet irradiation step with an aqueous self-assembled monolayer removing solution, thereby selectively removing the self-assembled monolayer;
A substrate processing method comprising: The removal step
2. A 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. 1. The substrate processing method according to 1. The removing step comprises:
3. The substrate processing method according to claim 2, further comprising the step of contacting the aqueous self-assembled monolayer removal solution with the self-assembled monolayer after the ultraviolet ray irradiation step while applying ultrasonic vibration to the aqueous self-assembled monolayer removal solution, thereby selectively removing the self-assembled monolayer. The removing step comprises:
3. The substrate processing method according to claim 2, further comprising the step of selectively removing the self-assembled monolayer by contacting the self-assembled monolayer with droplets of the aqueous self-assembled monolayer removal solution produced by contacting the aqueous self-assembled monolayer removal solution with a gas, the droplets being contacted with the self-assembled monolayer. 5. The substrate processing method according to claim 1, wherein the irradiation intensity of the ultraviolet light is in the range of 1 mW/cm ² to 50 mW/cm ² . The substrate processing method according to any one of claims 1 to 4, wherein the aqueous self-assembled monolayer removal solution contains at least an organic acid. 5. The substrate processing method according to claim 1, wherein the aqueous self-assembled monolayer removal solution has an acid dissociation constant pKa of -4 or more and 14 or less. A substrate processing apparatus for processing a substrate provided with a self-assembled monolayer on the surface,
an ultraviolet irradiation unit that irradiates ultraviolet rays;
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 includes:
causing the ultraviolet irradiation unit to irradiate the self-assembled monolayer with ultraviolet rays in an atmosphere containing oxygen atoms, thereby reducing the water repellency of the surface of the self-assembled monolayer;
A substrate processing apparatus that causes the supply unit to supply the aqueous self-assembled monolayer removal solution to the surface of the substrate, thereby selectively removing the self-assembled monolayer. The supply section includes an ultrasonic application section,
9. The substrate processing apparatus according to claim 8, wherein the control section applies ultrasonic vibration to the aqueous self-assembled monolayer removal liquid by controlling the ultrasonic wave applying section. the supply unit is a droplet supply unit that supplies the aqueous self-assembled monolayer removal solution in droplet form,
9. The substrate processing apparatus according to claim 8, wherein the control unit controls the droplet supply unit to bring the aqueous self-assembled monolayer removal solution into contact with a gas, generate droplets of the aqueous self-assembled monolayer removal solution, and spray the droplets toward the self-assembled monolayer. The substrate according to any one of claims 8 to 10, wherein the control unit controls the ultraviolet ray irradiation unit to set the irradiation intensity of the ultraviolet light in a range of 1 mW/cm ² or more and 50 mW/cm ² or less. Processing equipment. The substrate processing apparatus according to any one of claims 8 to 10, wherein the aqueous self-assembled monolayer removal solution contains at least an organic acid. The substrate processing apparatus according to any one of claims 8 to 10, wherein the acid dissociation constant pKa of the aqueous self-assembled monolayer removal solution is -4 or more and 14 or less.

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