Film forming method and film forming apparatus

Abstract

To provide a technique selectively forming an object film in a desired region when the object film is formed by using a metal catalyst-containing gas and a silanol group-containing gas.SOLUTION: A film forming method has the following (A) to (C). (A) A substrate is prepared, the substrate having, in different regions of the surface thereof, a first film and a second film that is formed of a different material from the first film. (B) A film formation inhibitory film for inhibiting the formation of an object film is selectively formed on the surface of the second film with respect to the surface of the first film. (C) The object film is selectively formed on the surface of the first film with respect to the surface of the second film by using the film formation inhibitory film. The object film contains at least silicon (Si) and oxygen (O). The (C) includes: (Ca) supplying a metal catalyst-containing gas to the surface of the substrate; (Cb) supplying a plasma-converted gas to the surface of the substrate after the (Ca); and (Cc) supplying a silanol group-containing gas to the surface of the substrate after the (Cb).SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] The film formation method described in Patent Document 1 includes, in this order, forming a polyimide film or a self-assembled monolayer selectively on the surface of a metal film relative to the surface of a dielectric film, and forming a silicon oxide film selectively on the surface of a dielectric film relative to the surface of the metal film. The silicon oxide film is formed using a metal catalyst and silanol. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent Application Publication No. 2021 / 301392 Summary of the Invention [Problem to be solved by the invention]

[0004] One aspect of the present disclosure provides a technique for selectively forming a target film in a desired region when forming the target film using a metal catalyst-containing gas and a silanol group-containing gas. [Means for solving the problem]

[0005] A film formation method according to one embodiment of the present disclosure includes the following steps (A) to (C): (A) preparing a substrate having a first film and a second film formed of a material different from the first film on different regions of its surface; (B) selectively forming a film-formation-inhibiting film that inhibits the formation of a target film on the surface of the second film relative to the surface of the first film; (C) selectively forming the target film on the surface of the first film relative to the surface of the second film using the film-formation-inhibiting film. The target film contains at least silicon (Si) and oxygen (O). (C) includes: (Ca) supplying a metal catalyst-containing gas to the surface of the substrate to adsorb a metal catalyst onto the surface of the first film; (Cb) after (Ca), supplying a gas plasma to the surface of the substrate to remove at least a portion of the metal catalyst adsorbed to the film-formation-inhibiting film in (Ca); and (Cc) after (Cb), supplying a silanol group-containing gas to the surface of the substrate. [Effects of the Invention]

[0006] According to one aspect of the present disclosure, when a target film is formed using a metal catalyst-containing gas and a silanol group-containing gas, the target film can be selectively formed in a desired region. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a flowchart showing a film forming method according to one embodiment. [Figure 2] FIG. 2 is a flowchart showing an example of the subroutine of S105. [Figure 3] FIG. 3 is a flowchart showing an example of the subroutine of S106. [Figure 4] Figure 4(A) is a cross-sectional view showing a first example of S101, Figure 4(B) is a cross-sectional view showing first examples of S102 and S103, Figure 4(C) is a cross-sectional view showing a first example of S104, Figure 4(D) is a cross-sectional view showing a first example of S105a, Figure 4(E) is a cross-sectional view showing a first example of S105b, and Figure 4(F) is a cross-sectional view showing a first example of S105c. [Figure 5]Figure 5(A) is a cross-sectional view showing a second example of S101, Figure 5(B) is a cross-sectional view showing second examples of S102 and S103, Figure 5(C) is a cross-sectional view showing a second example of S104, Figure 5(D) is a cross-sectional view showing a second example of S105a, Figure 5(E) is a cross-sectional view showing a second example of S105b, and Figure 5(F) is a cross-sectional view showing a second example of S105c. [Figure 6] Figure 6(A) is a cross-sectional view showing a third example of S101, Figure 6(B) is a cross-sectional view showing third examples of S102 and S103, Figure 6(C) is a cross-sectional view showing a third example of S104, Figure 6(D) is a cross-sectional view showing a third example of S105a, Figure 6(E) is a cross-sectional view showing a third example of S105b, and Figure 6(F) is a cross-sectional view showing a third example of S105c. [Figure 7] FIG. 7 is a plan view showing a film forming apparatus according to an embodiment. [Figure 8] FIG. 8 is a cross-sectional view showing an example of the first processing section of FIG. [Figure 9] FIG. 9 is a diagram showing XPS (X-ray photoelectron spectroscopy) spectra of the substrate surfaces obtained in Examples 4 and 5. As shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same reference numerals, and descriptions thereof may be omitted.

[0009] A film formation method according to one embodiment will be described mainly with reference to Figures 1 to 6. The film formation method includes, for example, steps S101 to S107 shown in Figure 1. Note that the film formation method only needs to include at least steps S101, and S104 to S105, and does not necessarily include steps S102 to S103 and S106. The film formation method may also include steps other than steps S101 to S107 shown in Figure 1.

[0010] Step S101 includes preparing a substrate 1, as shown in FIG. 4(A). The substrate 1 includes a base substrate 10. The base substrate 10 is, for example, a silicon wafer, a compound semiconductor wafer, or a glass substrate. The substrate 1 has an insulating film 11 and a conductive film 12 in different regions of its surface 1a. The substrate surface 1a is, for example, the upper surface of the substrate 1. The insulating film 11 and the conductive film 12 are formed on the base substrate 10. Another functional film may be formed between the base substrate 10 and the insulating film 11 or between the base substrate 10 and the conductive film 12. The insulating film 11 is an example of a first film, and the conductive film 12 is an example of a second film. The materials of the first film and the second film are not particularly limited.

[0011] The insulating film 11 is, for example, an interlayer insulating film. The interlayer insulating film is preferably a low-dielectric constant (Low-k) film. The insulating film 11 is not particularly limited, but may be, for example, an SiO film, a SiN film, a SiOC film, a SiON film, or a SiOCN film. Here, the SiO film means a film containing silicon (Si) and oxygen (O). The atomic ratio of Si to O in the SiO film is usually 1:2, but is not limited to 1:2. The SiN film, the SiOC film, the SiON film, and the SiOCN film also mean that they contain the respective elements, and are not limited to the stoichiometric ratio. The insulating film 11 has a recess in the substrate surface 1a. The recess is a trench, a contact hole, or a via hole.

[0012] The conductive film 12 fills, for example, recesses in the insulating film 11. The conductive film 12 is, for example, a metal film. The metal film is, for example, a Cu film, a Co film, a Ru film, a W film, or a Mo film. The conductive film 12 may also be a cap film. That is, as shown in FIG. 6(A), a second conductive film 15 may be embedded in the recesses in the insulating film 11, and the second conductive film 15 may be covered by the conductive film 12. The second conductive film 15 is made of a metal different from that of the conductive film 12. For example, the second conductive film 15 is a Cu film, and the conductive film 12 (cap film) is a Co film or a Ru film.

[0013] The substrate 1 may further have a third film on the substrate surface 1a. The third film is, for example, a barrier film 13. The barrier film 13 is formed between the insulating film 11 and the conductive film 12 and suppresses metal diffusion from the conductive film 12 to the insulating film 11. The barrier film 13 is not particularly limited, but may be, for example, a TaN film or a TiN film. Here, the TiN film refers to a film containing titanium (Ti) and nitrogen (N). The atomic ratio of Ti to N in a TiN film is usually 1:1, but is not limited to 1:1. Similarly, a TaN film refers to a film containing each element and is not limited to a stoichiometric ratio.

[0014] The substrate 1 may further have a fourth film on the substrate surface 1a. The fourth film is, for example, a liner film 14 (see FIGS. 5(A) and 6(A)). The liner film 14 is formed between the conductive film 12 and the barrier film 13. The liner film 14 is formed on the barrier film 13 and assists in the formation of the conductive film 12. The conductive film 12 is formed on the liner film 14. For example, the conductive film 12 is a Cu film and the liner film 14 is a Co film or a Ru film.

[0015] As shown in FIGS. 4(A), 5(A), and 6(A), contaminants 22 may be present on the substrate surface 1a. The contaminants 22 may be, for example, metal oxides. The metal oxides are formed, for example, by a reaction between the conductive film 12 and the atmosphere. The contaminants 22 may also be organic matter. The organic matter may be, for example, a deposit containing carbon, which adheres to the substrate 1 during processing. The organic matter may be in the form of a layer.

[0016] Step S102 includes performing a first pre-processing step to remove contaminants 22 from the substrate surface 1a, as shown in FIGS. 4(B), 5(B), and 6(B). In the first pre-processing step, a cleaning gas is supplied to the substrate surface 1a. Multiple cleaning gases may be supplied in sequence. In this embodiment, a first cleaning gas, a second cleaning gas, and a third cleaning gas are supplied in this order.

[0017] The first cleaning gas contains at least a reducing gas such as H2 gas, and may contain a nitrogen-containing gas such as N2 gas in addition to the reducing gas. The first cleaning gas is preferably converted into plasma before being supplied to the substrate surface 1a.

[0018] An example of the treatment conditions for the first cleaning gas is shown below. H2 gas flow rate: 50sccm to 5000sccm N2 gas flow rate: 50sccm to 10,000sccm Ar gas flow rate: 20sccm to 10,000sccm The ratio of H2 gas in the first cleaning gas: 10% to 60% by volume Ratio of N2 gas in the first cleaning gas: 10% to 80% by volume Power frequency for plasma generation: 10MHz to 100MHz Plasma generation power: 50W~400W Processing time: 5 to 120 seconds Processing temperature (substrate temperature): 80℃~350℃ Processing pressure: 50Pa~2000Pa.

[0019] The second cleaning gas contains an oxygen-containing gas. The oxygen-containing gas contains at least one selected from O gas, O gas, H O gas, NO gas, NO gas, and N O gas. The oxygen-containing gas is supplied to the substrate surface 1a without being converted into plasma.

[0020] An example of the processing conditions using the second cleaning gas is shown below. O2 gas flow rate: 100sccm to 2000sccm Processing time: 10 seconds to 5 minutes Processing temperature (substrate temperature): 80℃~350℃ Processing pressure: 50Pa~665Pa.

[0021] The third cleaning gas includes at least one selected from, for example, a carboxylic acid compound, a phosphonic acid compound, a nitro compound, and a thiol compound. The carboxylic acid compound is represented by the general formula "R-COOH". The phosphonic acid compound is represented by the general formula "RP(=O)(OH)2". The nitro compound is represented by the general formula "R-NO2". The thiol compound is represented by the general formula "R-SH".

[0022] In these general formulas, R is, for example, a hydrocarbon group or a hydrocarbon group in which at least a portion of the hydrogen atoms has been substituted with fluorine atoms. Specifically, for example, R is "CF3-(CF2) X -", "CF3-(CF2) X -CH2-CH2-" or "CH3-(CH2) X -". X is an integer from 1 to 17. Specific examples of carboxylic acid compounds include PFBA (CF3(CF2)2COOH), formic acid (HCOOH), acetic acid (CH3COOH), propionic acid (CH3CH2COOH), and octanoic acid (CH3(CH2)6COOH). Specific examples of nitro compounds include PFNO (CF3(CF2)5CH2CH2NO2).

[0023] An example of the treatment conditions for the third cleaning gas is shown below. PFBA gas flow rate: 10sccm to 100sccm Processing time: 30 seconds to 10 minutes Processing temperature (substrate temperature): 80℃~350℃ Processing pressure: 100Pa~300Pa.

[0024] Step S103 includes performing a second pre-processing step to remove residues of the cleaning gas supplied in step S102. The residues of the cleaning gas are primarily organic matter. In the second pre-processing step, plasma-converted gas is supplied to the substrate surface 1a. The gas contains at least a reducing gas such as H2 gas, and may contain a nitrogen-containing gas such as N2 gas in addition to the reducing gas. The processing conditions for step S103 are the same as those for step S102 using the first cleaning gas, and therefore will not be described here.

[0025] Step S104, as shown in FIGS. 4(C), 5(C), and 6(C), involves selectively forming a self-assembled monolayer 17 on the surface of the conductive film 12 relative to the surface of the insulating film 11. Hereinafter, the self-assembled monolayer (SAM) 17 may be referred to as SAM17. The SAM17 is formed by supplying an organic compound gas to the substrate surface 1a. The organic compound gas is a raw material gas for the SAM17.

[0026] The source gas for SAM17 is not particularly limited, but may include, for example, a thiol-based compound. Specific examples of thiol-based compounds include CF3(CF2)5CH2CH2SH (1H,1H,2H,2H-perfluorooctanethiol: PFOT) and CH3(CH2)5SH (hexanethiol: HT). Thiol-based compounds are more likely to chemically adsorb to the surface of the conductive film 12 than to the surface of the insulating film 11. Therefore, SAM17 is selectively formed on the surface of the conductive film 12 relative to the surface of the insulating film 11. SAM17 is hardly formed on the surface of the insulating film 11. SAM17 may be formed not only on the surface of the conductive film 12 but also on the surface of the liner film 14, as shown in FIGS. 5(C) and 6(C).

[0027] The source gas for SAM17 is not limited to a thiol-based compound. The source gas for SAM17 may also include a phosphonic acid-based compound, a carboxylic acid-based compound, or a nitro-based compound. The first cleaning gas and the source gas for SAM17 may contain the same or different organic compounds, but preferably contain the same organic compound. Using the same organic compound can reduce costs by, for example, reducing the number of chambers used.

[0028] The source gas for SAM17 may contain an olefin-based compound or an organic silane-based compound. An olefin-based compound is represented by the general formula "R-CH=CH2". An organic silane-based compound is, for example, a trichlorosilane-based, methoxysilane-based, or ethoxysilane-based compound. A trichlorosilane-based organic compound is represented by the general formula "R-SiCl3". A methoxysilane-based organic compound is represented by the general formula "R-Si(OCH3)3". An ethoxysilane-based organic compound is represented by the general formula "R-Si(OCH2CH3)3".

[0029] An example of the processing conditions in step S104 is shown below. HT gas flow rate: 50sccm to 200sccm Processing time: 3 to 120 seconds Processing temperature: 80℃~350℃ Processing pressure: 50Pa~4000Pa.

[0030] Step S104 may include selectively forming a deposition-inhibiting film that inhibits the formation of the target film on the surface of the second film relative to the surface of the first film. The insulating film 11 is an example of the first film, the conductive film 12 is an example of the second film, and the SAM 17 is an example of the deposition-inhibiting film. The deposition-inhibiting film is not limited to a SAM and may be, for example, a graphene-containing film.

[0031] 4(D) to 4(F), 5(D) to 5(F), and 6(D) to 6(F), step S105 includes selectively forming a second insulating film 18 on the surface of the insulating film 11 relative to the surface of the conductive film 12 using a SAM 17. The second insulating film 18 is an example of a target film.

[0032] The second insulating film 18 is, for example, an SiO film containing at least silicon (Si) and oxygen (O). The SiO film is formed using, for example, a metal catalyst-containing gas and a silanol group-containing gas. The metal catalyst-containing gas contains a metal catalyst. The metal catalyst promotes a dehydration condensation reaction of the silanol groups contained in the silanol group-containing gas. The SiO film is formed by the dehydration condensation reaction of the silanol groups. The SiO film may contain a metal catalyst in addition to silicon (Si) and oxygen (O).

[0033] The metal catalyst-containing gas is preferably an organometallic compound gas. Specific examples include organoaluminum compound gas and organotitanium compound gas. The organoaluminum compound gas is, for example, trimethylaluminum (TMA) gas, triethylaluminum (TEA) gas, dimethylaluminum chloride gas, or dimethylaluminum isopropoxide (DMAI). The organotitanium compound gas is, for example, tetrakis(dimethylamino)titanium (TDMAT) gas.

[0034] The silanol group-containing gas is not particularly limited, but examples thereof include tris(tert-pentoxy)silanol (TPSOL), triethylsilanol, methyl bis(tert-pentoxy)silanol, and tris(tert-butoxy)silanol (TBSOL).

[0035] Step S105 includes, for example, as shown in FIG. 2, supplying a metal catalyst-containing gas (step S105a), supplying a plasmatized gas (step S105b), and supplying a silanol group-containing gas (step S105c) K times (K is an integer of 1 or more). K may be an integer of 2 or more, and steps S105a to S105c may be repeated multiple times. K is preferably 1 to 5. Step S105 of this embodiment differs from Patent Document 1 in that it includes step S105b.

[0036] As shown in FIGS. 4(D), 5(D), and 6(D), step S105a includes supplying a metal catalyst-containing gas to the substrate surface 1a to adsorb a metal catalyst 18A onto the surface of the insulating film 11. The SAM 17 inhibits the metal catalyst 18A from adsorbing onto the surface of the conductive film 12. However, the metal catalyst 18A may be adsorbed onto the surface of the SAM 17, although the amount (number) of adsorption is smaller than that onto the surface of the insulating film 11. The same applies when, for example, a graphene-containing film is used as the film-formation-inhibiting film.

[0037] An example of the processing conditions in step S105a is shown below. TMA gas flow rate: 10sccm to 100sccm Processing time: 0.05 seconds to 100 seconds Processing temperature: 80℃~350℃ Processing pressure: 133Pa~1200Pa.

[0038] 4(E), 5(E), and 6(E), step S105b includes supplying plasma gas to the substrate surface 1a to remove at least a portion of the metal catalyst 18A adsorbed on the surface of the SAM 17. The plasma gas removes at least a portion (preferably only a portion) of the SAM 17, thereby removing at least a portion (preferably all) of the metal catalyst 18A adsorbed on the surface of the SAM 17.

[0039] The gas to be converted into plasma is, for example, H2 gas, a rare gas, or a mixture of H2 gas and a rare gas. The rare gas is, for example, Ar gas or He gas. The plasma decomposes the surface of SAM 17, thereby desorbing metal catalyst 18A adsorbed on the surface of SAM 17. At this time, some of metal catalyst 18A adsorbed on the surface of insulating film 11 may also be desorbed upon contact with the plasma-converted gas. However, because the adsorption amount (number) is large, even if some of the metal catalyst 18A is desorbed, the amount of metal catalyst 18A required to promote the dehydration condensation reaction of silanol groups contained in the silanol group-containing gas can be secured.

[0040] According to this embodiment, after the supply of the metal catalyst-containing gas (step S105a) and before the supply of the silanol group-containing gas (step S105c), at least a portion (preferably all) of the metal catalyst 18A adsorbed on the surface of the SAM 17 is removed. This makes it possible to prevent the second insulating film 18 from depositing on the surface of the conductive film 12, increase the opening width of the second insulating film 18, and reduce the wiring resistance of the substrate 1.

[0041] Even when a graphene-containing film is formed in step S104 instead of the SAM 17 as a film-formation inhibiting film that inhibits the formation of the second insulating film 18, by supplying plasmatized gas to the substrate surface 1a, at least a part (preferably all) of the metal catalyst 18A adsorbed on the surface of the graphene-containing film is removed. This makes it possible to prevent the second insulating film 18 from being deposited on the surface of the conductive film 12, increase the opening width of the second insulating film 18, and reduce the wiring resistance of the substrate 1.

[0042] An example of the processing conditions in step S105b is shown below. H2 gas flow rate: 200sccm to 3000sccm Ar gas flow rate: 100sccm to 6000sccm The ratio of H2 gas in the mixture of H2 gas and Ar gas: 0% to 90% by volume Power supply frequency for plasma generation: 10MHz to 60MHz Plasma generation power: 50W~600W Processing time: 2 seconds to 120 seconds Processing temperature: 80℃~350℃ Processing pressure: 50Pa~1200Pa.

[0043] Step S105c includes supplying a silanol group-containing gas to the substrate surface 1a, as shown in FIGS. 4(F), 5(F), and 6(F). The metal catalyst 18A adsorbed on the surface of the insulating film 11 promotes a dehydration condensation reaction of the silanol groups contained in the silanol group-containing gas. As a result, a second insulating film 18 is selectively formed on the surface of the insulating film 11 relative to the surface of the conductive film 12.

[0044] An example of the processing conditions for step S105c is shown below: Note that the TPSOL gas is supplied by vaporizing TPSOL liquid. TPSOL gas flow rate: 0.1g / min~0.5g / min Processing time: 3 to 120 seconds Processing temperature: 80℃~350℃ Processing pressure: 133Pa~1200Pa.

[0045] In step S105, after the supply of the metal catalyst-containing gas (step S105a) and before the supply of the silanol group-containing gas (step S105c), it is preferable that SAM 17 remain on the surface of the conductive film 12. The remaining SAM 17 can inhibit the adsorption of the silanol group-containing gas. The remaining SAM 17 is also useful in step S106.

[0046] Although not shown, the blocking performance of the SAM 17 is not perfect, and the second insulating film 18 may protrude laterally from the surface of the insulating film 11 and cover part of the surface of the conductive film 12. This narrows the opening width of the second insulating film 18, increasing the wiring resistance of the substrate 1. Therefore, the substrate processing method may include step S106.

[0047] Step S106 includes preferentially etching a portion of the second insulating film 18 relative to another portion of the second insulating film 18. The portion of the second insulating film 18 includes a portion deposited on the surface of the conductive film 12 and includes a portion of the SAM 17. Therefore, the portion of the second insulating film 18 has more defects and is etched at a faster rate than the other portion of the second insulating film 18.

[0048] Even when a graphene-containing film or the like is formed in step S104 instead of the SAM 17 as a film-deposition-inhibiting film that inhibits the formation of the second insulating film 18, the etching rate of the portion 18a of the second insulating film 18 is faster than that of the other portion 18b of the second insulating film 18. This is because the growth of the second insulating film (the portion 18a of the second insulating film 18) in the vicinity of the film-deposition-inhibiting film is inhibited by the film-deposition-inhibiting film, resulting in a thinner film or a lower density.

[0049] 3, step S106 includes, for example, supplying a fluorine-containing gas (step S106a), supplying an HO gas (step S106b), and supplying a plasmatized gas (step S106c). Step S106 includes performing steps S106b and S106c a set number of times (M times). M may be an integer of 2 or greater, and steps S106b to S106c may be repeated multiple times. Step S106 also includes performing step S106a once and steps S106b and S106c M times, all of which are performed a set number of times (L times). L may be an integer of 2 or greater, and steps S106a to S106c may be repeated multiple times.

[0050] Although not shown, step S106a includes supplying a fluorine-containing gas to the surface of the second insulating film 18 to form a fluorine-containing layer on the surface of the second insulating film 18. The fluorine-containing layer may be deposited not only on the surface of the second insulating film 18 but also on the surface of the SAM 17. Note that instead of forming a fluorine-containing layer on the surface of the second insulating film 18, fluorine may be adsorbed onto the surface of the second insulating film 18.

[0051] The fluorine-containing gas is, for example, a mixed gas of HF gas and NH3 gas. A fluorine-containing layer is formed by the reaction between the mixed gas of HF gas and NH3 gas and the second insulating film 18. When the second insulating film 18 is a film containing silicon (Si) and oxygen (O), the fluorine-containing layer contains ammonium silicofluoride ((NH4)2SiF6).

[0052] The fluorine-containing layer may be formed to such an extent that unnecessary portions of the second insulating film 18 can be etched in steps S106b to S106c. To prevent excessive formation of the fluorine-containing layer, step S106a is preferably performed at a lower temperature than steps S106b to S106c. The temperature of the substrate 1 in step S106a is, for example, 50°C to 100°C.

[0053] In this embodiment, the fluorine-containing gas is a mixed gas of HF gas and NH3 gas, but it may not contain NH3 gas and may contain only HF gas. In this case, instead of forming a fluorine-containing layer on the surface of the second insulating film 18, fluorine can be adsorbed on the surface of the second insulating film 18.

[0054] An example of the processing conditions in step S106a is shown below. HF gas flow rate: 10sccm to 100sccm NH3 gas flow rate: 10sccm to 100sccm Processing time: 0.05 seconds to 100 seconds Processing temperature: 50℃~100℃ Processing pressure: 133Pa~1200Pa.

[0055] Step S106b includes generating hydrogen fluoride by supplying H2O gas to the surface of the second insulating film 18. The hydrogen fluoride is generated by a reaction between the fluorine-containing layer and the H2O gas. Note that it is also possible to generate hydrogen fluoride by a reaction between fluorine adsorbed on the surface of the second insulating film 18 and the H2O gas, instead of the fluorine-containing layer. In step S106b, H2O2 gas may be used in addition to the H2O gas. It is preferable not to convert the H2O gas into plasma in step S106b. This can prevent the generation of oxygen plasma and oxidation of the conductive film 12.

[0056] An example of the processing conditions in step S106b is shown below. H2O gas flow rate: 10sccm to 500sccm Processing time: 0.1sec~120sec Processing temperature: 80℃~350℃ Processing pressure: 50Pa~1200Pa.

[0057] Step S106c includes supplying plasmatized gas to the surface of the second insulating film 18. By performing steps S106b and S106c in order, it is possible to prevent the HO gas from becoming plasmatized, prevent the generation of oxygen plasma, and prevent the conductive film 12 from being oxidized.

[0058] The gas to be converted into plasma in step S106c preferably does not contain an oxygen-based gas to prevent the generation of oxygen plasma. The gas to be converted into plasma is, for example, H2 gas, a rare gas, or a mixed gas of H2 gas and a rare gas. The rare gas is, for example, Ar gas or He gas. The plasma promotes the decomposition of the fluorine-containing layer or the desorption of fluorine, and promotes the generation of hydrogen fluoride. This promotes the etching of the second insulating film 18 by hydrogen fluoride.

[0059] According to this embodiment, a portion of the second insulating film 18 is etched preferentially relative to another portion of the second insulating film 18. While the unnecessary portion of the second insulating film 18 (the portion deposited on the surface of the conductive film 12) is etched, the necessary portion of the second insulating film 18 (the portion deposited on the surface of the insulating film 11) is hardly etched. Therefore, the unnecessary portion of the second insulating film 18 can be selectively removed.

[0060] An example of the processing conditions in step S106c is shown below. H2 gas flow rate: 200sccm to 3000sccm Ar gas flow rate: 100sccm to 6000sccm The ratio of H2 gas in the mixture of H2 gas and Ar gas: 0% to 90% by volume Power supply frequency for plasma generation: 10MHz to 60MHz Plasma generation power: 50W~600W Processing time: 2 seconds to 120 seconds Processing temperature: 80℃~350℃ Processing pressure: 50Pa~1200Pa.

[0061] Step S106d includes checking whether steps S106b to S106c have been performed a set number of times (M times). If the number of times has not reached the set number of times (M times), etching of second insulating film 18 is insufficient, so steps S106b to S106c are performed again. On the other hand, if the number of times has reached the set number of times (M times), etching of second insulating film 18 is sufficient, so processing from step S106e onwards is performed.

[0062] The set number of times (M times) in step S106d is, for example, 1 to 50 times, and preferably 2 to 50 times. When M is an integer equal to or greater than 2, steps S106b to S106c are repeated multiple times. The decomposition of the fluorine-containing layer or the desorption of fluorine can be gradually promoted, and hydrogen fluoride can be generated over a long period of time. As a result, the opening width of the second insulating film 18 can be increased, and the wiring resistance of the substrate 1 can be reduced.

[0063] Step S106e includes performing step S106a once, and performing steps S106b to S106c M times, and checking whether these steps have been performed a set number of times (L times). If the number of times has not reached the set number of times (L times), etching of second insulating film 18 is insufficient, so steps S106a to S106c are performed again. On the other hand, if the number of times has reached the set number of times (L times), etching of second insulating film 18 is sufficient, so processing from step S107 onwards is performed.

[0064] The set number of times (L times) in step S106e is, for example, 1 to 50 times, and preferably 2 to 50 times. When L is an integer equal to or greater than 2, steps S106a to S106c are repeated multiple times. The fluorine-containing layer 19 can be regenerated, and hydrogen fluoride can be generated over a long period of time. As a result, the opening width of the second insulating film 18 can be increased, and the wiring resistance of the substrate 1 can be reduced. In this case, the wiring resistance includes the resistance of via wiring that penetrates between layers, and increasing the opening width can also improve the yield of non-defective vias.

[0065] Step S107 involves checking whether steps S104 to S106 have been performed a set number of times (N times). If the number of times has not reached the set number, the thickness of second insulating film 18 has not reached the target thickness, so steps S104 to S106 are performed again. On the other hand, if the number of times has reached the set number of times, the thickness of second insulating film 18 has reached the target thickness, so this processing ends.

[0066] Next, with reference to FIG. 7, a film formation apparatus 100 for carrying out the above-described film formation method will be described. As shown in FIG. 7, the film formation apparatus 100 includes a first processing unit 200A, a second processing unit 200B, a third processing unit 200C, a fourth processing unit 200D, a transfer unit 400, and a control unit 500. The first processing unit 200A performs steps S102 to S103 of FIG. 1. The second processing unit 200B performs step S104 of FIG. 1. The third processing unit 200C performs step S105 of FIG. 1. The fourth processing unit 200D performs step S106 of FIG. 1. The first processing unit 200A, the second processing unit 200B, the third processing unit 200C, and the fourth processing unit 200D may have similar structures or different structures. It is also possible to carry out all of steps S102 to S106 of FIG. 1 using only the first processing unit 200A. The transport unit 400 transports the substrate 1 to the first processing unit 200A, the second processing unit 200B, the third processing unit 200C, and the fourth processing unit 200D. The control unit 500 controls the first processing unit 200A, the second processing unit 200B, the third processing unit 200C, the fourth processing unit 200D, and the transport unit 400.

[0067] The transfer section 400 has 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. 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 vertically and horizontally and rotatable around a vertical axis. The second transfer chamber 411 is connected to a first processing unit 200A, a second processing unit 200B, a third processing unit 200C, and a fourth processing unit 200D via different gate valves G.

[0069] Furthermore, the transfer section 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 unit 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 unit 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 unit 500 controls the first processing unit 200A, the second processing unit 200B, the third processing unit 200C, the fourth processing unit 200D, and the transfer unit 400 to perform the above-described film forming method.

[0071] Next, the operation of the film forming apparatus 100 will be described. First, the first transfer mechanism 402 removes the substrate 1 from the carrier C, transfers the removed substrate 1 to the load lock chamber 421, and exits from 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 transfer mechanism 412 removes the substrate 1 from the load lock chamber 421 and transfers the removed substrate 1 to the first processing unit 200A.

[0072] Next, first processing unit 200A performs steps S102 and S103. Thereafter, second transport mechanism 412 removes substrate 1 from first processing unit 200A and transports it to second processing unit 200B. During this time, the atmosphere around substrate 1 can be maintained at a vacuum atmosphere, and unintended oxidation of substrate 1 can be suppressed.

[0073] Next, second processing unit 200B performs step S104. Thereafter, second transport mechanism 412 removes substrate 1 from second processing unit 200B and transports it to third processing unit 200C. During this time, the atmosphere around substrate 1 can be maintained at a vacuum atmosphere, and degradation of the blocking performance of SAM 17 can be suppressed.

[0074] Next, third processing unit 200C performs step S105. Thereafter, second transport mechanism 412 removes substrate 1 from third processing unit 200C and transports it to fourth processing unit 200D. During this time, the atmosphere around substrate 1 can be maintained at a vacuum atmosphere, and unintended oxidation of substrate 1 can be suppressed.

[0075] Next, fourth processing unit 200D performs step S106. Thereafter, control unit 500 checks whether steps S104 to S106 have been performed a set number of times (N times). If the number of times has not reached the set number, second transport mechanism 412 removes substrate 1 from fourth processing unit 200D and transports the removed substrate 1 to second processing unit 200B. Thereafter, control unit 500 controls second processing unit 200B, third processing unit 200C, fourth processing unit 200D, and transport unit 400 to perform steps S104 to S106 again.

[0076] On the other hand, if the number of times has reached the set number (N times), the second transport mechanism 412 removes the substrate 1 from the fourth processing unit 200D, 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.

[0077] Next, first processing unit 200A will be described with reference to Fig. 8. Second processing unit 200B, third processing unit 200C, and fourth processing unit 200D are configured similarly to first processing unit 200A, and therefore will not be illustrated or described here.

[0078] 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.

[0079] 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.

[0080] A transfer port 215 is provided on the side 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 a second transfer chamber 411 (see FIG. 7) via the transfer port 215.

[0081] A stage 220, which is 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, for example, with a diameter of 300 mm, is formed in 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 made of a ceramic material such as aluminum nitride (AlN). Alternatively, the stage 220 may be made 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.

[0082] A grounded lower electrode 223 is embedded in the stage 220, for example. 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 the control unit 500 (see FIG. 7), 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 (e.g., three) lifting pins 231 for holding and lifting the substrate 1 placed on the stage 220. The material of the lifting pins 231 may be, for example, ceramics such as alumina (Al2O3), quartz, or the like. The lower ends of the lifting pins 231 are attached to a support plate 232. The support plate 232 is connected to a lifting mechanism 234 provided outside the processing vessel 210 via a lifting shaft 233 .

[0083] 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.

[0084] A gas supply unit 240 is provided on the ceiling wall 217 of the processing chamber 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, and capacitively coupled plasma is generated. 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 generating capacitively coupled plasma, and may generate other types of plasma, such as inductively coupled plasma. Note that in steps that do not generate plasma (e.g., step S104), the gas supply unit 240 does not need to serve as the upper electrode, and the lower electrode 223 is also not required.

[0085] 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 unit 500.

[0086] 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 gas used in at least one of steps S102 to S106 in FIG. 1 to the gas supply chamber 241 via the gas supply path 261. Although not shown, the gas supply mechanism 260 includes an individual pipe for each type of gas, an on-off valve provided midway through the individual pipe, and a flow rate controller provided midway through the individual pipe. When the on-off valve opens the individual pipe, 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 valve closes the individual pipe, the supply of gas from the supply source to the gas supply path 261 is stopped.

[0087] [Example] Next, experimental data will be explained. First, Examples 1 to 3 will be explained with reference to Table 1. In Examples 1 to 3, substrates having a low-k film and a Cu film in different regions of the substrate surface were prepared, and the substrates were processed under the conditions shown in Table 1. Examples 1 and 2 are comparative examples, and Example 3 is an example.

[0088] [Table 1]

[0089] In Examples 1 to 3, steps S102 to S104 were set under the same conditions. In step S102, a plasma-converted mixed gas containing H2 gas and N2 gas was supplied for 15 seconds, followed by O2 gas for 30 seconds and then PFBA gas. In step S103, plasma-converted H2 gas was supplied for 30 seconds. In step S104, HT gas was supplied for 60 seconds to selectively form a SAM on the surface of the Cu film.

[0090] In Example 1, steps S102 to S104 were followed by steps S105a and S105c, and then steps S106b and S106c were repeated six times. In step S105a, TMA gas was supplied for 10 seconds. In step S105c, TPSOL gas was supplied for 15 seconds. In step S106b, H2O gas was supplied for 10 seconds. In step S106c, plasmatized H2 gas was supplied for 30 seconds. Steps S105b and S106a were not performed. In Example 1, the set number of times (M times) for step S106d was 6, and the set number of times (N times) for step S107 was 2. Note that step S106a was not performed, so the set number of times (L times) for step S106e was 0.

[0091] In Example 2, steps S102 to S104 were followed by steps S105a and S105c, then step S106a was performed using a mixed gas of HF gas and NH3 gas, and steps S106b and S106c were repeated three times. In step S106a, the mixed gas of HF gas and NH3 gas was supplied for 7 seconds. Step S105b was not performed. In Example 2, the set number of times (M times) for step S106d was 3, the set number of times (L times) for step S106e was 1, and the set number of times (N times) for step S107 was 3.

[0092] In Example 2, the number of times (N times) of step S107 is set to 3 in order to make the thickness of the SiO film obtained in Example 2 approximately the same as the thickness of the SiO film obtained in Examples 1 and 3.

[0093] In Example 3, steps S102 to S104 were followed by steps S105a, S105b, and S105c. In step S105b, plasmatized H2 gas was supplied for 30 seconds. Steps S106a, S106b, and S106c were not performed. In Example 3, the set number of times (N times) for step S107 was 2.

[0094] As is clear from a comparison of the opening widths of the SiO films obtained in Examples 1, 2, and 3 in Table 1, it is clear that if step S105b is performed after step S105a and before step S105c, a sufficient opening width can be obtained without performing step S106.

[0095] Furthermore, as is clear from a comparison of the opening widths of the SiO film obtained in Example 1 and Example 2 in Table 1, it can be seen that the opening width of the SiO film can be widened by performing all of steps S106a, S106b, and S106c.

[0096] Next, Examples 4 to 5 will be described. In Examples 4 to 5, a substrate having a Cu film formed on the entire surface of a silicon wafer was prepared, and the substrate was processed under the conditions shown in Table 2. Examples 4 to 5 are reference examples. In Example 4, only steps S102 to S104 were performed, whereas in Example 5, steps S102 to S104 were followed by steps S105a and S105b.

[0097] [Table 2]

[0098] Figure 9 shows the XPS (X-ray photoelectron spectroscopy) spectra of the substrate surfaces obtained in Examples 4 and 5. From Figure 9, it can be seen that even after S105b was performed, the peak of S2p contained in the SAM was still observable, indicating that the SAM remained.

[0099] 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. [Explanation of symbols]

[0100] 1 board 1a Substrate surface 11 Insulating film (first film) 12 Conductive film (second film) 17 SAM (Self-assembled monolayer) 18 Second insulating film (target film)

Claims

1. (A) preparing a substrate having a first film and a second film formed of a material different from that of the first film in different regions of its surface; (B) selectively forming a film-formation inhibiting film that inhibits formation of a target film on a surface of the second film relative to a surface of the first film; (C) selectively forming the target film on the surface of the first film relative to the surface of the second film using the film formation inhibiting film; having The target film contains at least silicon (Si) and oxygen (O); The (C) is (Ca) supplying a metal catalyst-containing gas to the surface of the substrate to adsorb a metal catalyst onto the surface of the first film; (Cb) after (Ca), supplying a plasmatized gas to the surface of the substrate to remove at least a portion of the metal catalyst adsorbed on the surface of the film-formation-inhibiting film in (Ca); (Cc) after (Cb), supplying a silanol group-containing gas to the surface of the substrate; The film forming method includes the steps of:

2. The film forming method according to claim 1 , wherein the first film is an insulating film and the second film is a conductive film.

3. 3. The film formation method according to claim 1, wherein the film formation inhibiting film is a self-assembled monolayer.

4. The film formation method according to claim 1 , wherein the film formation inhibiting film is a graphene-containing film.

5. The film forming method according to claim 3 , wherein the self-assembled monolayer remains on the surface of the second film after (Cb) and before (Cc).

6. The film forming method according to claim 1 , wherein the steps (Ca), (Cb) and (Cc) are repeated a plurality of times.

7. The gas to be converted into plasma in (Cb) is H ２ Gas, rare gas, or H ２ The method of claim 1 or 2, further comprising a mixed gas of a gas and a rare gas.

8. The film forming method according to claim 1 , wherein the steps (B) and (C) are repeated a plurality of times.

9. The film forming method according to claim 1 or 2, further comprising (D) etching the target film that protrudes laterally from the surface of the second film after (C).

10. The film forming method according to claim 9 , wherein the steps (B), (C), and (D) are repeated a plurality of times.

11. A processing vessel; a holder for holding the substrate inside the processing vessel; a gas supply mechanism for supplying a gas into the processing chamber; a plasma generating unit for generating plasma from a gas supplied to the inside of the processing chamber; a gas exhaust mechanism for exhausting gas from inside the processing vessel; a transport mechanism for transporting the substrate into and out of the processing vessel; a control unit that controls the gas supply mechanism, the plasma generating unit, the gas exhaust mechanism, and the transport mechanism to perform the film forming method according to claim 1 or 2; A film forming apparatus comprising:

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