Film formation method and film formation device

Abstract

This film formation method includes, in order: preparing a substrate that has a first metal film and a first insulating film in different regions on a surface thereof; using a first molecular bonding agent to form a first bonding film on both the surface of the first insulating film and the surface of the first metal film; forming a second metal film on the surface of the first bonding film, bonding the first insulating film and the second metal film with the bonding film, and bonding the first metal film and the second metal film with the bonding film; and causing diffusion to occur at the interface between the first bonding film and the first metal film and the interface between the first bonding film and the second metal film, by subjecting the substrate to an annealing treatment.

Description

Film forming method and film forming apparatus

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

[0002] The film formation method described in Patent Document 1 includes, in this order, forming a TiN film along the recesses of an interlayer insulating film and then filling the recesses of the interlayer insulating film with a Ru film. The TiN film improves the adhesion of the Ru film to the interlayer insulating film.

[0003] The bonding method described in Patent Document 2 bonds a first substrate and a second substrate using a compound having an OH group or an OH yielding group, an azide group, and a triazine ring in one molecule.

[0004] Japanese Patent Application Publication No. 2022-152438 International Publication No. 2012 / 043631

[0005] An embodiment of the present disclosure provides a technique for reducing the electrical resistance between a first metal film and a second metal film and improving the adhesion between the first insulating film and the second metal film.

[0006] A film forming method according to an embodiment of the present disclosure includes, in this order, preparing a substrate having a first metal film and a first insulating film on different regions of its surface, forming a first bonding film on both the surface of the first insulating film and the surface of the first metal film using a first molecular bonding agent, forming a second metal film on the surface of the first bonding film, bonding the first insulating film to the second metal film and bonding the first metal film to the second metal film with the first bonding film, and annealing the substrate to cause diffusion at an interface between the first bonding film and the first metal film and an interface between the first bonding film and the second metal film. The first molecular bonding agent is an organic compound having a first functional group and a second functional group in one molecule, the first functional group more easily bonding to the first insulating film than the second functional group, and the second functional group more easily bonding to the second metal film than the first functional group.

[0007] According to an embodiment of the present disclosure, it is possible to reduce the electrical resistance between the first metal film and the second metal film, and also improve the adhesion between the first insulating film and the second metal film.

[0008] FIG. 1 is a flowchart showing a film forming method according to a first embodiment. FIG. 2A is a cross-sectional view showing step S101 in FIG. 1 . FIG. 2B is a cross-sectional view showing step S102 in FIG. 1 . FIG. 2C is a cross-sectional view showing step S103 in FIG. 1 . FIG. 2D is a cross-sectional view showing step S104 in FIG. 1 . FIG. 2E is a cross-sectional view showing step S105 in FIG. 1 . FIG. 3 is a TEM image showing an example of a substrate before and after annealing. FIG. 4 is a TEM image showing another example of a substrate before and after annealing. FIG. 5 is a graph showing an example of the relationship between volume resistivity and annealing temperature. FIG. 6 is a flowchart showing a film forming method according to a second embodiment. FIG. 7A is a cross-sectional view showing step S101 in FIG. 6 . FIG. 7B is a cross-sectional view showing step S102 in FIG. 6 . FIG. 7C is a cross-sectional view showing step S103 in FIG. 6 . FIG. 7D is a cross-sectional view showing step S104 in FIG. 6 . FIG. 7E is a cross-sectional view showing step S105 in FIG. 6 . FIG. 7F is a cross-sectional view showing step S106 in FIG. 6 . FIG. 8 is a flowchart showing a film forming method according to a third example, and is a flowchart showing processing performed following S104 in FIG. 6. FIG. 9A is a cross-sectional view showing S111 in FIG. 8. FIG. 9B is a cross-sectional view showing S112 in FIG. 8. FIG. 9C is a cross-sectional view showing S113 in FIG. 8. FIG. 9D is a cross-sectional view showing S114 in FIG. 8. FIG. 9E is a cross-sectional view showing S115 in FIG. 8. FIG. 10 is a plan view showing a film forming apparatus according to an embodiment. FIG. 11 is a cross-sectional view showing an example of the first processing unit in FIG. 10.

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or similar components are denoted by the same reference numerals, and descriptions thereof may be omitted.

[0010] A film formation method according to a first embodiment will be described with reference to FIGS. 1 and 2A to 2E. The film formation method according to the first embodiment forms metal wiring by a dual damascene method. As shown in FIG. 1, the film formation method according to the first embodiment includes steps S101 to S105. Note that the film formation method may include steps other than steps S101 to S105. For example, the film formation method may include a step of cleaning the substrate surface between steps S101 and S102.

[0011] Step S101 includes preparing a substrate 1, as shown in FIG. 2A . The substrate 1 includes a semiconductor substrate or a glass substrate (not shown) and various functional films formed on the semiconductor substrate or the glass substrate. The substrate 1 includes a first metal film 11 and a first insulating film 12 in different regions of the substrate surface 1a. The first metal film 11 is, for example, a Ru film. The first metal film 11 may contain Ru, and may also be a Ru alloy film. The first metal film 11 may also be a Cu film, a Co film, a W film, or a Mo film. The first metal film 11 may also be an alloy film containing at least one of Cu, Co, W, and Mo. The first insulating film 12 is, for example, an interlayer insulating film.

[0012] The interlayer insulating film is preferably a SiO film or a low-dielectric-constant (Low-k) film having a dielectric constant lower than that of a SiO film. The Low-k film is not particularly limited, but is, for example, a SiCO film, a SiOCH film, or a SiCN film. Here, the SiO film means a film containing silicon (Si) and oxygen (O). The atomic ratio of the elements constituting the SiO film is not limited to a stoichiometric ratio. The SiCO film, the SiOCH film, and the SiCN film similarly mean that they contain the respective elements, and the atomic ratio of the elements constituting each film is not limited to a stoichiometric ratio.

[0013] The substrate 1 has a recess 1b on its surface 1a. The recess 1b has, for example, a trench 1c and a via hole 1d formed in the bottom surface of the trench 1c. The substrate 1 has a surface of a first metal film 11 on the bottom surface of the recess 1b and a surface of a first insulating film 12 on the side surface of the recess 1b. The substrate 1 also has a top surface of a protrusion 1e on its surface 1a and a recess 1b recessed from the top surface of the protrusion 1e. The substrate 1 has a surface of the first insulating film 12 on the top surface of the protrusion 1e.

[0014] The substrate 1 may further include a second insulating film 13. The second insulating film 13 is, for example, an interlayer insulating film. A first metal film 11 and a first adhesive film 14 are filled in this order into the recesses of the second insulating film 13. The first adhesive film 14 improves adhesion between the first metal film 11 and an etching stopper film 15, which will be described later. The first adhesive film 14 is, for example, a TiN film or a TaN film. The atomic ratio of the elements constituting the TiN film or the TaN film is not limited to the stoichiometric ratio.

[0015] The substrate 1 may further include an etching stopper film 15. The etching stopper film 15 is formed on the second insulating film 13 and the first adhesive film 14. The etching stopper film 15 stops the etching of the first insulating film 12 to form the recess 1b. The etching stopper film 15 is, for example, a SiN film or a SiCN film. The atomic ratio of elements constituting the SiN film or SiCN film is not limited to the stoichiometric ratio.

[0016] After etching of the first insulating film 12 to form the recess 1b is completed, a part of the etching stopper film 15 and a part of the first adhesive film 14 are removed to expose the first metal film 11 on the bottom surface of the recess 1b (see FIG. 2A ). As a result, the substrate 1 may have a surface of the first adhesive film 14 and a surface of the etching stopper film 15 on the side surface of the recess 1b.

[0017] Step S102 includes forming a first bonding film 16 as shown in FIG. 2B . The first bonding film 16 is formed on both the surface of the first insulating film 12 and the surface of the first metal film 11. The first bonding film 16 may be formed over the entire substrate surface 1a, following the shape of the substrate surface 1a. The first bonding film 16 may also be formed on the surface of the first adhesive film 14 and the surface of the etching stopper film 15 inside the recess 1b. The material of the first bonding film 16 is a first molecular bonding agent. The first molecular bonding agent may be supplied in a liquid state dissolved in an organic solvent, or in a gaseous state vaporized by heating.

[0018] The first molecular binder is an organic compound having a first functional group and a second functional group in one molecule. The first functional group bonds more easily to the first insulating film 12 than the second functional group. The first functional group is not particularly limited, but includes, for example, at least one of a silanol group and a group that generates a silanol group upon hydrolysis. The group that generates a silanol group upon hydrolysis is, for example, an alkoxysilyl group. A single molecule may contain multiple first functional groups, and the multiple first functional groups may be the same or different.

[0019] The second functional group is more likely to bond to the second metal film 17 (described later) than the first functional group. The second functional group is also more likely to bond to the first metal film 11 than the first functional group. The second functional group is not particularly limited, but includes, for example, at least one of an amino group, an azide group, a mercapto group, an isocyanate group, a ureido group, and an epoxy group. A single molecule may contain a plurality of second functional groups, and the plurality of second functional groups may be the same or different.

[0020] The first molecular binder preferably has a triazine between the first functional group and the second functional group, and may include at least one of benzene, cyclohexane, naphthalene, a spiro compound, a lactone, pyridine, cyclopentane, furan, and thiophene instead of triazine.

[0021] Step S103 includes forming a second metal film 17 as shown in FIG. 2C . The second metal film 17 is, for example, a Ru film. The second metal film 17 may contain Ru, and may be a Ru alloy film. The second metal film 17 may be a Cu film, a Co film, a W film, or a Mo film. The second metal film 17 may also be an alloy film containing at least one of Cu, Co, W, and Mo. The second metal film 17 is formed by, for example, a PVD (Physical Vapor Deposition) method, a CVD (Chemical Vapor Deposition) method, or a plating method.

[0022] The second metal film 17 fills the recess 1b. The second metal film 17 contacts the first bonding film 16 at the bottom surface of the recess 1b. The second metal film 17 also contacts the first bonding film 16 at the side surface of the recess 1b and the top surface of the protrusion 1e. The first bonding film 16 bonds the first insulating film 12 and the second metal film 17. This makes it possible to suppress peeling of the second metal film 17 from the first insulating film 12.

[0023] The first bonding film 16 bonds the first insulating film 12 and the second metal film 17, and also bonds the first metal film 11 and the second metal film 17. The first bonding film 16 may also bond the first adhesion film 14 and the second metal film 17. The first bonding film 16 may also bond the etching stopper film 15 and the second metal film 17.

[0024] Step S104 includes annealing the substrate 1 as shown in FIG. 2D. Annealing the substrate 1 preferably includes heating the substrate 1 to 400° C. or higher. If the annealing temperature is 400° C. or higher, diffusion, which will be described later, is likely to proceed even if the annealing time is short. The annealing time is set depending on the annealing temperature, and is, for example, 1 to 60 minutes, and preferably 1 to 30 minutes.

[0025] Step S104 includes causing diffusion at the interface between the first bonding film 16 and the first metal film 11 and at the interface between the first bonding film 16 and the second metal film 17. The first bonding film 16 has a modified layer 16A sandwiched between the first metal film 11 and the second metal film 17. The modified layer 16A is a layer formed by the diffusion of the first molecular bonding agent constituting the first bonding film 16, and has a lower volume resistivity than the first bonding film 16 before the annealing treatment. Therefore, the contact resistance between the first metal film 11 and the second metal film 17 can be reduced.

[0026] The modified layer 16A may be formed not only by diffusion but also by grain growth of metal particles. The metal particles of the first metal film 11 and the metal particles of the second metal film 17 grow by annealing. The grain-grown metal particles of the first metal film 11 and the second metal film 17 may aggregate into a single metal particle beyond the first bonding film 16.

[0027] If the objective is not to reduce the contact resistance between the first metal film 11 and the second metal film 17 but to improve the adhesion between the first insulating film 12 and the second metal film 17, it is also possible to use a second adhesive film (not shown) instead of the first bonding film 16. The second adhesive film, like the first adhesive film, is made of an inorganic material such as a TiN film or a TaN film.

[0028] Unlike the second adhesive film (not shown), the first bonding film 16 is made of an organic material. Organic materials are more likely to diffuse during annealing than inorganic materials such as TiN or TaN films. Furthermore, organic materials are more likely to be broken down by grain growth of metal particles than inorganic materials such as TiN or TaN films. Therefore, this embodiment can achieve both a reduction in contact resistance between the first metal film 11 and the second metal film 17 and an improvement in adhesion between the first insulating film 12 and the second metal film 17.

[0029] From the viewpoint of diffusion rate, it is preferable that the first metal film 11 and the second metal film 17 contain the same metal element. It is preferable that the first metal film 11 and the second metal film 17 contain the same metal element not only from the viewpoint of diffusion rate but also from the viewpoint of grain growth of metal particles. For example, it is preferable that the first metal film 11 and the second metal film 17 contain Ru.

[0030] The thickness of the first bonding film 16 is preferably 0.05 nm to 1.0 nm. If the thickness of the first bonding film 16 is 0.05 nm or more, the adhesion between the first insulating film 12 and the second metal film 17 is good. If the thickness of the first bonding film 16 is 1.0 nm or less, the thickness of the modified layer 16A of the first bonding film 16 is thin, and the contact resistance between the first metal film 11 and the second metal film 17 is low.

[0031] Step S105 includes polishing the second metal film 17 as shown in FIG. 2E. The polishing method is, for example, CMP (Chemical Mechanical Polishing). Step S105 includes polishing the second metal film 17 and the first insulating film 12 simultaneously, after polishing the second metal film 17. The surfaces of the second metal film 17 and the first insulating film 12 are aligned in the same plane. Metal wiring can be formed from the second metal film 17 embedded in the first insulating film 12.

[0032] Note that step S104 may be performed after step S105. However, step S104 may cause dimensional changes. Therefore, step S104 is preferably performed before step S105.

[0033] Next, experimental data will be described with reference to FIGS. 3 to 5. FIG. 3 is a TEM image showing an example of a substrate before and after annealing. In the experiment shown in FIG. 3, the substrate was heated at 400°C for 10 minutes in a nitrogen atmosphere for annealing. The substrate was a silicon wafer (not shown) on which a SiO film, an MB (molecular bonding) film, and a Ru film were deposited in that order. The SiO film was formed by CVD using TEOS (tetraethoxysilane). The MB film was formed by applying a molecular bonding agent by spin coating and heating at 200°C for 30 minutes. The Ru film was formed by PVD. The SiO film is an example of the first insulating film 12, the MB film is an example of the first bonding film 16, and the Ru film is an example of the second metal film 17. As shown in FIG. 3, the Ru film adhered closely to the SiO film both before and after annealing. The thickness of the MB film was 0.2 nm both before and after the annealing treatment, and almost no diffusion due to the annealing treatment was observed.

[0034] FIG. 4 shows TEM images of another example of a substrate before and after annealing. In the experiment shown in FIG. 4, the annealing was performed by heating the substrate in a nitrogen atmosphere at 400°C or 500°C for 10 minutes. The substrate was a silicon wafer (not shown) on which a first Ru film, an MB film, and a second Ru film were deposited in that order, or the first Ru film and the second Ru film were deposited in that order without an MB film. The first Ru film was formed by CVD. The MB film was formed by spin-coating a molecular bonding agent and heating at 200°C for 30 minutes. The second Ru film was formed by PVD. The first Ru film is an example of the first metal film 11, the MB film is an example of the first bonding film 16, and the second Ru film is an example of the second metal film 17. As shown in FIG. 4, the second Ru film was closely adhered to the first Ru film both before and after the annealing. Furthermore, the MB film disappeared from the TEM image due to the annealing treatment, which suggests that the annealing treatment caused the diffusion of the molecular binder that constitutes the MB film.

[0035] FIG. 5 shows an example of the relationship between volume resistivity and annealing temperature. In FIG. 5, R1 is the volume resistivity of a laminate film including a first Ru film, an MB film, and a second Ru film, in that order, before annealing; R2 is the volume resistivity of a laminate film including a first Ru film and a second Ru film, in that order, without an MB film, before annealing; and Ta is the annealing temperature. In the experiment shown in FIG. 5, substrates were fabricated under the same conditions as in the experiment shown in FIG. 4. From FIG. 5, it can be seen that the higher the annealing temperature, the lower R1, R2, and (R1 / R2) all become. The reason why R2 decreases with increasing annealing temperature is due to grain growth of Ru particles. Since (R1 / R2) decreases with increasing annealing temperature, it is presumed that the annealing treatment causes the diffusion of the molecular binder that constitutes the MB film.

[0036] Next, a film deposition method according to a second embodiment will be described with reference to Figures 6 and 7A to 7F. The film deposition method according to the second embodiment forms metal wiring by a semi-damascene method. The film deposition method according to the second embodiment includes steps S101 to S106, as shown in Figure 6. The following mainly describes the differences from the first embodiment.

[0037] Step S101 includes preparing a substrate 1 as shown in Fig. 7A. The substrate 1 has a recess 1b on a substrate surface 1a. The recess 1b has a via hole 1d as shown in Fig. 2A but does not have a trench 1c as shown in Fig. 2B. The substrate 1 has a top surface of a protrusion 1e on the substrate surface 1a and a recess 1b recessed from the top surface of the protrusion 1e.

[0038] Step S102 includes forming a first bonding film 16, as shown in FIG. 7B. The first bonding film 16 is formed on both the surface of the first insulating film 12 and the surface of the first metal film 11. The first bonding film 16 may be formed over the entire substrate surface 1a, following the shape of the substrate surface 1a. The material of the first bonding film 16 is a first molecular bonding agent.

[0039] Step S103 includes forming a second metal film 17 as shown in FIG. 7C. The second metal film 17 fills the recess 1b. The second metal film 17 contacts the first bonding film 16 at the bottom surface of the recess 1b. The second metal film 17 also contacts the first bonding film 16 at the side surface of the recess 1b and the top surface of the protrusion 1e.

[0040] The first bonding film 16 bonds the first insulating film 12 and the second metal film 17, and also bonds the first metal film 11 and the second metal film 17. The first bonding film 16 may also bond the first adhesion film 14 and the second metal film 17. The first bonding film 16 may also bond the etching stopper film 15 and the second metal film 17.

[0041] Step S104 includes annealing the substrate 1, as shown in FIG. 7D . Step S104 includes inducing diffusion at the interface between the first bonding film 16 and the first metal film 11 and at the interface between the first bonding film 16 and the second metal film 17. The first bonding film 16 has a modified layer 16A sandwiched between the first metal film 11 and the second metal film 17. The modified layer 16A is a layer formed by the diffusion of the first molecular bonding agent constituting the first bonding film 16, and has a lower volume resistivity than the first bonding film 16 before the annealing treatment. Therefore, the contact resistance between the first metal film 11 and the second metal film 17 can be reduced.

[0042] If the objective is not to reduce the contact resistance between the first metal film 11 and the second metal film 17 but to improve the adhesion between the first insulating film 12 and the second metal film 17, it is also possible to use a second adhesive film (not shown) instead of the first bonding film 16. The second adhesive film, like the first adhesive film, is made of an inorganic material such as a TiN film or a TaN film.

[0043] Unlike the second adhesive film (not shown), the first bonding film 16 is made of an organic material. Organic materials are more likely to diffuse during annealing than inorganic materials such as TiN or TaN films. Furthermore, organic materials are more likely to be broken down by the grain growth of metal particles than inorganic materials such as TiN or TaN films. Therefore, according to this embodiment, similar to the first embodiment, it is possible to achieve both a reduction in contact resistance between the first metal film 11 and the second metal film 17 and improved adhesion between the first insulating film 12 and the second metal film 17.

[0044] Step S105 includes polishing the second metal film 17, as shown in Figure 7E. The second metal film 17 is planarized. The second metal film 17 covers the first insulating film 12, and the surface of the first insulating film 12 is not exposed.

[0045] Step S106 includes patterning the second metal film 17 as shown in Fig. 7F. For the patterning, for example, photolithography and etching techniques are used. Metal wiring can be formed from the remaining second metal film 17.

[0046] Note that step S104 may be performed after step S105 and before step S106, or may be performed after steps S105 and S106. However, step S104 may cause dimensional changes. Therefore, it is preferable to perform step S104 before steps S105 and S106.

[0047] A film formation method according to the third embodiment will be described with reference to Figures 8 and 9A to 9E. The film formation method according to the third embodiment forms metal wiring by a semi-damascene method, which is different from that of the second embodiment. As shown in Figure 8, the film formation method according to the third embodiment includes steps S111 to S115 following step S104 in Figure 6. The following mainly describes the differences from the second embodiment.

[0048] 9A , step S111 includes polishing the second metal film 17. After polishing the second metal film 17, step S111 includes simultaneously polishing the second metal film 17 and the first insulating film 12. The surfaces of the second metal film 17 and the first insulating film 12 are aligned in the same plane.

[0049] Step S112 includes forming a second bonding film 18 as shown in FIG. 9B . The second bonding film 18 is formed on both the surface of the second metal film 17 and the surface of the first insulating film 12. The second bonding film 18 may be formed over the entire substrate surface 1a, conforming to the shape of the substrate surface 1a. The material of the second bonding film 18 is a second molecular bonding agent. The second molecular bonding agent may be supplied in a liquid state dissolved in an organic solvent, or in a gaseous state vaporized by heating.

[0050] The second molecular binder is an organic compound having a third functional group and a fourth functional group in one molecule. The third functional group is more likely to bond to the first insulating film 12 than the fourth functional group. The third functional group is not particularly limited, but includes, for example, at least one of a silanol group and a group that generates a silanol group upon hydrolysis. The group that generates a silanol group upon hydrolysis is, for example, an alkoxysilyl group. A plurality of third functional groups may be present in one molecule, and the plurality of third functional groups may be the same or different.

[0051] The fourth functional group is more likely to bond to the third metal film 19 (described later) than the third functional group. The fourth functional group is also more likely to bond to the second metal film 17 than the third functional group. The fourth functional group is not particularly limited, but includes, for example, at least one of an amino group, an azide group, a mercapto group, an isocyanate group, a ureido group, and an epoxy group. A single molecule may contain a plurality of fourth functional groups, and the plurality of fourth functional groups may be the same or different.

[0052] The second molecular binder preferably has a triazine between the third and fourth functional groups, and may include at least one of benzene, cyclohexane, naphthalene, a spiro compound, a lactone, pyridine, cyclopentane, furan, and thiophene instead of triazine.

[0053] Step S113 includes forming a third metal film 19 as shown in FIG. 9C . The third metal film 19 is, for example, a Ru film. The third metal film 19 may contain Ru, and may be a Ru alloy film. The third metal film 19 may be a Cu film, a Co film, a W film, or a Mo film. The third metal film 19 may also be an alloy film containing at least one of Cu, Co, W, and Mo. The third metal film 19 is formed by, for example, a PVD method, a CVD method, or a plating method.

[0054] Step S114 includes annealing the substrate 1 as shown in FIG. 9D. Annealing the substrate 1 preferably includes heating the substrate 1 to 400° C. or higher. If the annealing temperature is 400° C. or higher, diffusion, which will be described later, is likely to proceed even if the annealing time is short. The annealing time is set depending on the annealing temperature, and is, for example, 1 to 60 minutes, and preferably 1 to 30 minutes.

[0055] Step S114 includes causing diffusion at the interface between second bonding film 18 and second metal film 17 and at the interface between second bonding film 18 and third metal film 19. Second bonding film 18 has modified layer 18A sandwiched between second metal film 17 and third metal film 19. Modified layer 18A is a layer formed by diffusion of the second molecular bonding agent that constitutes second bonding film 18, and has a lower volume resistivity than second bonding film 18 before annealing. Therefore, the contact resistance between second metal film 17 and third metal film 19 can be reduced.

[0056] The modified layer 18A may be formed not only by diffusion but also by grain growth of metal particles. The metal particles of the second metal film 17 and the metal particles of the third metal film 19 may grow by annealing treatment, breaking the second bonding film 18 and joining them together.

[0057] If the objective is not to reduce the contact resistance between the second metal film 17 and the third metal film 19 but to improve the adhesion between the first insulating film 12 and the third metal film 19, it is also possible to use a third adhesive film (not shown) instead of the second bonding film 18. The third adhesive film is made of an inorganic material such as a TiN film or a TaN film, like the first adhesive film.

[0058] Unlike the third adhesive film (not shown), the second bonding film 18 is made of an organic material. Organic materials are more likely to diffuse during annealing than inorganic materials such as TiN or TaN films. Furthermore, organic materials are more likely to be broken down by the grain growth of metal particles than inorganic materials such as TiN or TaN films. Therefore, this embodiment can achieve both a reduction in contact resistance between the second metal film 17 and the third metal film 19 and an improvement in adhesion between the first insulating film 12 and the third metal film 19.

[0059] From the viewpoint of the diffusion rate, it is preferable that the second metal film 17 and the third metal film 19 contain the same metal element. It is preferable that the second metal film 17 and the third metal film 19 contain the same metal element not only from the viewpoint of the diffusion rate but also from the viewpoint of grain growth of metal particles. For example, it is preferable that the second metal film 17 and the third metal film 19 contain Ru.

[0060] The thickness of the second bonding film 18 is preferably 0.05 nm to 1.0 nm. If the thickness of the second bonding film 18 is 0.05 nm or more, the adhesion between the first insulating film 12 and the third metal film 19 is good. If the thickness of the second bonding film 18 is 1.0 nm or less, the thickness of the modified layer 18A of the second bonding film 18 is thin, and the contact resistance between the second metal film 17 and the third metal film 19 is low.

[0061] Step S115 includes patterning the third metal film 19 as shown in Fig. 9E. For the patterning, for example, photolithography and etching techniques are used. Metal wiring can be formed from the remaining third metal film 19.

[0062] Note that step S114 may be performed after step S115. However, step S114 may cause dimensional changes. Therefore, step S114 is preferably performed before step S115.

[0063] 8 may be performed following step S103 in Fig. 6, or step S114 may serve as step S104. Steps S104 and S114 may be performed simultaneously. That is, the formation of the modified layer 16A of the first bonding film 16 and the formation of the modified layer 18A of the second bonding film 18 may be performed simultaneously.

[0064] The film forming method may also include preparing a substrate 1A (see FIG. 9A ) obtained in step S111 of the third embodiment. The substrate 1A has no recess on its surface 1Aa. The surface 1Aa is flat, and the surfaces of the second metal film 17 and the first insulating film 12 are aligned on the flat surface.

[0065] In this case, the second metal film 17 and the second bonding film 18 may correspond to the first metal film and the first bonding film described in the claims. Accordingly, in this case, the second bonding agent, the third functional group, and the fourth functional group may correspond to the first bonding agent, the first functional group, and the second functional group described in the claims.

[0066] Next, with reference to FIG. 10 , a film formation apparatus 100 for carrying out the above-described film formation method will be described. The film formation apparatus 100 carries out, for example, the film formation method shown in FIG. 1 . The film formation apparatus 100 may also carry out the film formation method shown in FIG. 6 or FIG. 8 . As shown in FIG. 10 , the film formation apparatus 100 includes a first processing unit 200A, a second processing unit 200B, a transport unit 400, and a control circuit 500. The first processing unit 200A carries out, for example, step S102 of FIG. 1 . The second processing unit 200B carries out, for example, steps S103 to S104 of FIG. 1 . The processes from step S105 onward are performed outside the film formation apparatus 100, but can also be performed inside the film formation apparatus 100. The first processing unit 200A and the second processing unit 200B may have similar structures or different structures. It is also possible for the first processing unit 200A alone to carry out all of steps S102 to S104 of FIG. 1 . The transport unit 400 transports the substrate 1 to the first processing unit 200A and the second processing unit 200B. The transport unit 400 loads the substrate W into the processing vessel 210 (see FIG. 11 ) such as the first processing unit 200A, and loads the substrate W out of the processing vessel 210. The control circuit 500 controls the first processing unit 200A, the second processing unit 200B, and the transport unit 400.

[0067] The transfer section 400 includes a first transfer chamber 401 and a first transfer mechanism 402. The internal atmosphere of the first transfer chamber 401 is atmospheric. The first transfer mechanism 402 is provided inside the first transfer chamber 401. A load port 405 is provided on a wall surface of the first transfer chamber 401. A carrier C accommodating a substrate 1 is attached to the load port 405. For example, a front-opening unified pod (FOUP) or the like can be used as the carrier C. The first transfer mechanism 402 includes an arm 403 that holds the substrate 1 and travels along rails 404. The rails 404 extend in the arrangement direction of the carriers C.

[0068] The transfer unit 400 also has a second transfer chamber 411 and a second transfer mechanism 412. The internal atmosphere of the second transfer chamber 411 is a vacuum atmosphere. The second transfer mechanism 412 is provided inside the second transfer chamber 411. The second transfer mechanism 412 includes an arm 413 that holds the substrate 1, and the arm 413 is arranged to be movable in the vertical and horizontal directions and rotatable around a vertical axis. The second transfer chamber 411 is connected to the first processing unit 200A and the second processing unit 200B via different gate valves G.

[0069] Furthermore, the transfer unit 400 has a load lock chamber 421 between the first transfer chamber 401 and the second transfer chamber 411. The internal atmosphere of the load lock chamber 421 can be switched between a vacuum atmosphere and an atmospheric atmosphere by a pressure adjustment mechanism (not shown). This allows the interior of the second transfer chamber 411 to be constantly maintained in a vacuum atmosphere. Also, it is possible to prevent gas from flowing from the first transfer chamber 401 into the second transfer chamber 411. Gate valves G are provided between the first transfer chamber 401 and the load lock chamber 421, and between the second transfer chamber 411 and the load lock chamber 421.

[0070] The control circuit 500 is, for example, a computer, and includes an arithmetic unit 501 such as a CPU (Central Processing Unit) and a storage unit 502 such as a memory. The storage unit 502 stores programs that control various processes executed in the film forming apparatus 100. The control circuit 500 controls the operation of the film forming apparatus 100 by causing the arithmetic unit 501 to execute the programs stored in the storage unit 502. The control circuit 500 controls the first processing unit 200A, the second processing unit 200B, and the transport unit 400 to perform the above-described film forming method.

[0071] The program, i.e., a computer program product, may be supplied in a form recorded on a removable storage medium such as a memory card, an optical disk, or a hard disk drive (HDD). The control circuit 500 reads the program from the storage medium and stores it in the storage unit 502. The storage unit 502 includes a storage medium such as an HDD, a solid state drive (SDD), or an electronically erasable programmable read-only memory (EEPROM). The program may be written in advance to the storage medium of the storage unit 502. The control circuit 500 may also obtain the program distributed by a remote server device or the like via a network or other communication.

[0072] The control circuit 500 includes electronic circuits such as a CPU, a graphics processing unit (GPU), a field programmable gate array (FPGA), or an application specific integrated circuit (ASIC). The control circuit 500 executes various control operations described in this specification by executing instruction codes stored in a storage medium such as a memory, or by being a circuit designed for a specific application.

[0073] Next, the operation of the film forming apparatus 100 will be described. First, the first transport mechanism 402 removes the substrate 1 from the carrier C, transports the removed substrate 1 to the load lock chamber 421, and exits the load lock chamber 421. Next, the internal atmosphere of the load lock chamber 421 is switched from the air atmosphere to a vacuum atmosphere. Thereafter, the second transport mechanism 412 removes the substrate 1 from the load lock chamber 421 and transports the removed substrate 1 to the first processing unit 200A.

[0074] Next, the first processing unit 200A performs step S102. Thereafter, the second transport mechanism 412 removes the substrate 1 from the first processing unit 200A and transports the removed substrate 1 to the second processing unit 200B. During this time, the atmosphere surrounding the substrate 1 can be maintained at a vacuum atmosphere, and unintended oxidation of the substrate 1 can be suppressed.

[0075] Next, the second processing unit 200B performs steps S103 and S104. The second transport mechanism 412 removes the substrate 1 from the second processing unit 200B, transports the removed substrate 1 to the load lock chamber 421, and exits from the load lock chamber 421. The internal atmosphere of the load lock chamber 421 is then switched from a vacuum atmosphere to an atmospheric atmosphere. Thereafter, the first transport mechanism 402 removes the substrate 1 from the load lock chamber 421 and stores the removed substrate 1 in the carrier C. Then, the processing of the substrate 1 is completed.

[0076] Next, the first processing unit 200A will be described with reference to Fig. 11. The second processing unit 200B has the same configuration as the first processing unit 200A, and therefore will not be shown or described here.

[0077] The first processing unit 200A includes a substantially cylindrical, airtight processing vessel 210. An exhaust chamber 211 is provided in the center of the bottom wall of the processing vessel 210. The exhaust chamber 211 has, for example, a substantially cylindrical shape that protrudes downward. An exhaust pipe 212 is connected to the exhaust chamber 211, for example, at a side surface of the exhaust chamber 211.

[0078] An exhaust source 272 is connected to the exhaust pipe 212 via a pressure controller 271. The pressure controller 271 includes a pressure adjustment valve such as a butterfly valve. The exhaust pipe 212 is configured so that the pressure inside the processing vessel 210 can be reduced by the exhaust source 272. The pressure controller 271 and the exhaust source 272 constitute a gas exhaust mechanism 270 that exhausts gas inside the processing vessel 210.

[0079] A transfer port 215 is provided on the side surface of the processing vessel 210. The transfer port 215 is opened and closed by a gate valve G. The substrate 1 is transferred in and out between the processing vessel 210 and the second transfer chamber 411 (see FIG. 10 ) via the transfer port 215.

[0080] A stage 220, which serves as a holder for holding the substrate 1, is provided within the processing vessel 210. The stage 220 holds the substrate 1 horizontally with the substrate surface 1a facing upward. The stage 220 is formed in a substantially circular shape in a plan view and is supported by a support member 221. A substantially circular recess 222 for placing the substrate 1, e.g., 300 mm in diameter, is formed on the surface of the stage 220. The recess 222 has an inner diameter slightly larger than the diameter of the substrate 1. The depth of the recess 222 is configured to be substantially the same as the thickness of the substrate 1, for example. The stage 220 is formed of a ceramic material such as aluminum nitride (AlN). Alternatively, the stage 220 may be formed of a metal material such as nickel (Ni). Note that instead of the recess 222, a guide ring for guiding the substrate 1 may be provided around the periphery of the surface of the stage 220.

[0081] A grounded lower electrode 223, for example, is embedded in the stage 220. A heating mechanism 224 is embedded below the lower electrode 223. The heating mechanism 224 receives power from a power supply unit (not shown) based on a control signal from a control circuit 500 (see FIG. 10), thereby heating the substrate 1 placed on the stage 220 to a set temperature. If the entire stage 220 is made of metal, the entire stage 220 functions as the lower electrode, so the lower electrode 223 does not need to be embedded in the stage 220. The stage 220 is provided with a plurality of (for example, three) lifting pins 231 for holding and lifting up and down the substrate 1 placed on the stage 220. The lifting pins 231 are made of a material such as alumina (Al ２ O ３ The lift pins 231 may be made of ceramics such as quartz or the like. The lower ends of the lift pins 231 are attached to a support plate 232. The support plate 232 is connected to a lift mechanism 234 provided outside the processing vessel 210 via a lift shaft 233.

[0082] The lifting mechanism 234 is installed, for example, below the exhaust chamber 211. The bellows 235 is provided between the lifting mechanism 234 and an opening 219 for the lifting shaft 233 formed in the lower surface of the exhaust chamber 211. The support plate 232 may be shaped so that it can be raised and lowered without interfering with the support member 221 of the stage 220. The lifting pins 231 are configured to be able to be raised and lowered by the lifting mechanism 234 between above and below the surface of the stage 220.

[0083] A gas supply unit 240 is provided on the ceiling wall 217 of the processing vessel 210 via an insulating member 218. The gas supply unit 240 serves as an upper electrode and faces the lower electrode 223. A high-frequency power supply 252 is connected to the gas supply unit 240 via a matching unit 251. By supplying high-frequency power of 450 kHz to 100 MHz from the high-frequency power supply 252 to the upper electrode (gas supply unit 240), a high-frequency electric field is generated between the upper electrode (gas supply unit 240) and the lower electrode 223, generating capacitively coupled plasma. A plasma generation unit 250 that generates plasma includes the matching unit 251 and the high-frequency power supply 252. Note that the plasma generation unit 250 is not limited to capacitively coupled plasma, and may generate other types of plasma, such as inductively coupled plasma. Note that in processes that do not generate plasma, the gas supply unit 240 does not need to serve as an upper electrode, and the lower electrode 223 is also unnecessary.

[0084] The gas supply unit 240 includes a hollow gas supply chamber 241. A number of holes 242 are arranged, for example, evenly, on the bottom surface of the gas supply chamber 241 to distribute and supply the processing gas into the processing vessel 210. A heating mechanism 243 is embedded in the gas supply unit 240, for example, above the gas supply chamber 241. The heating mechanism 243 is heated to a set temperature by receiving power from a power supply unit (not shown) based on a control signal from the control circuit 500.

[0085] A gas supply mechanism 260 is connected to the gas supply chamber 241 via a gas supply path 261. The gas supply mechanism 260 supplies gases used in the film formation method to the gas supply chamber 241 via the gas supply path 261. Although not shown, the gas supply mechanism 260 includes individual pipes for each type of gas, on-off valves provided midway through the individual pipes, and flow rate controllers provided midway through the individual pipes. When the on-off valves open the individual pipes, gas is supplied from the supply source to the gas supply path 261. The supply amount is controlled by the flow rate controller. On the other hand, when the on-off valves close the individual pipes, the supply of gas from the supply source to the gas supply path 261 is stopped.

[0086] Although the embodiments of the film forming method and film forming apparatus according to the present disclosure have been described above, the present disclosure is not limited to the above embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. These naturally fall within the technical scope of the present disclosure.

[0087] This application claims priority based on Japanese Patent Application No. 2024-124657, filed with the Japan Patent Office on July 31, 2024, the entire contents of which are incorporated herein by reference.

[0088] REFERENCE SIGNS LIST 1 substrate 1a substrate surface 11 first metal film 12 first insulating film 16 first bonding film 17 second metal film

Claims

1. A film formation method comprising, in this order: preparing a substrate having a first metal film and a first insulating film on different regions of its surface; forming a first bonding film on both the surface of the first insulating film and the surface of the first metal film using a first molecular bonding agent; forming a second metal film on the surface of the first bonding film, bonding the first insulating film to the second metal film with the first bonding film and bonding the first metal film to the second metal film with the first bonding film; and annealing the substrate to cause diffusion at the interface between the first bonding film and the first metal film and at the interface between the first bonding film and the second metal film; wherein the first molecular bonding agent is an organic compound having a first functional group and a second functional group in one molecule, the first functional group more easily bonding to the first insulating film than the second functional group, and the second functional group more easily bonding to the second metal film than the first functional group.

2. The film forming method according to claim 1, wherein the first functional group includes at least one of a silanol group and a group that generates a silanol group by a hydrolysis reaction.

3. The film forming method according to claim 1, wherein the second functional group includes at least one of an amino group, an azide group, a mercapto group, an isocyanate group, a ureido group, and an epoxy group.

4. The film forming method according to claim 1, wherein the first molecular binder has a triazine between the first functional group and the second functional group.

5. The film forming method according to claim 1, wherein the first metal film and the second metal film contain the same metal element.

6. The film forming method according to claim 1, wherein the first metal film and the second metal film contain Ru.

7. The film forming method according to claim 1, wherein the substrate has a recess on the surface, the bottom surface of the recess has the surface of the first metal film, and the side surface of the recess has the surface of the first insulating film.

8. The film deposition method according to claim 1, wherein annealing the substrate includes heating the substrate to 400° C. or higher.

9. The film formation method of claim 1, comprising the steps of: polishing the second metal film to align a surface of the second metal film and a surface of the first insulating film in the same plane; forming a second bonding film on both the surface of the first insulating film and the surface of the second metal film using a second molecular bonding agent; forming a third metal film on the surface of the second bonding film, bonding the first insulating film and the third metal film with the second bonding film and bonding the second metal film and the third metal film with the second bonding film; and annealing the substrate to cause diffusion at the interface between the second bonding film and the second metal film and at the interface between the second bonding film and the third metal film, wherein the second molecular bonding agent is an organic compound having a third functional group and a fourth functional group in one molecule, the third functional group more easily bonding to the first insulating film than the fourth functional group, and the fourth functional group more easily bonding to the third metal film than the third functional group.

10. A film forming method as described in claim 9, wherein diffusion is simultaneously caused at the interface between the first bonding film and the first metal film and the interface between the first bonding film and the second metal film, and diffusion is simultaneously caused at the interface between the second bonding film and the second metal film and the interface between the second bonding film and the third metal film.

11. A film formation apparatus comprising: a processing vessel; a processing unit including a holding unit that holds the substrate inside the processing vessel; a heating mechanism that heats the substrate held in the holding unit; a gas supply mechanism that supplies gas into the processing vessel; and a gas exhaust mechanism that exhausts gas from the processing vessel; a transport unit that transports the substrate into and out of the processing vessel; and a control circuit that controls the processing unit and the transport unit so as to perform the film formation method described in any one of claims 1 to 10.

Images