Film forming method and film forming apparatus

Abstract

To provide a technique for improving the density of an SAM.SOLUTION: A deposition method includes the following steps (A)-(C). The step (A) prepares a substrate which has a first film and a second film formed of a different material from the first film in different regions of a surface. The step (B) reforms the surface of the substrate by supplying reformed gas transformed into plasma to the surface of the substrate. The step (C) forms a self-assembled monolayer selectively on the surface of the second film with respect to the surface of the first film after the step (B). The reformed gas used in the step (B) includes hydrogen and oxygen or includes hydrogen and nitrogen. The step (C) includes: (Ca) supplying gas of carboxylic acid being a precursor of the self-assembled monolayer into a processing container; and (Cb) maintaining the state in which supply of the gas of carboxylic acid into the processing container is stopped or the state in which a supply flow amount of the gas of carboxylic acid is reduced in comparison to the step (Ca) for a set time.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] Patent Document 1 describes a film formation method in which a self-assembled monolayer (SAM) is used to inhibit the formation of a target film on one part of a substrate surface while forming a target film on another part of the substrate surface. The film formation method described in Patent Document 1 involves repeatedly exposing the substrate surface to a precursor of the SAM and exposing the substrate surface to a precursor of an OH group. The precursor of the SAM contains a carboxylic acid. The precursor of the OH group contains water vapor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2019-512877 Summary of the Invention [Problem to be solved by the invention]

[0004] One aspect of the present disclosure provides techniques for increasing the density of SAMs. [Means for solving the problem]

[0005] A film forming 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) modifying the surface of the substrate by supplying a modifying gas in plasma form to the surface of the substrate; (C) after step (B), selectively forming a self-assembled monolayer on the surface of the second film relative to the surface of the first film. The modifying gas used in step (B) contains hydrogen and oxygen or contains hydrogen and nitrogen. Step (C) includes: (Ca) accommodating the substrate in a processing vessel and reducing the pressure inside the processing vessel; and (Cb) stopping the supply of the carboxylic acid gas into the processing vessel or maintaining a state in which the supply of the carboxylic acid gas into the processing vessel is stopped or the supply flow rate of the carboxylic acid gas is reduced compared to step (Ca) for a set time. [Effects of the Invention]

[0006] According to one aspect of the present disclosure, the density of the SAM can be improved. [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(A) is a diagram showing an example of step S1, FIG. 2(B) is a diagram showing an example of step S3, FIG. 2(C) is a diagram showing an example of step S4, and FIG. 2(D) is a diagram showing an example of step S6. [Figure 3] FIG. 3 is a flowchart showing an example of the subroutine of step S4. [Figure 4] FIG. 4 is a flowchart showing an example of the subroutine of step S6. [Figure 5] FIG. 5(A) is a diagram showing a modified example of step S3, FIG. 5(B) is a diagram showing a modified example of step S4, and FIG. 5(C) is a diagram showing a modified example of step S6. [Figure 6] FIG. 6 is a plan view showing a film forming apparatus according to an embodiment. [Figure 7] FIG. 7 is a cross-sectional view showing an example of the first processing section of FIG. [Figure 8] FIG. 8 is a graph showing the relationship between the water contact angle of the substrate surface obtained in Examples 1 to 3 and the time during which the supply of PFBA gas was stopped. [Figure 9] FIG. 9 is a graph showing the relationship between the F peak in the XPS spectrum of the substrate surface obtained in Example 1 and the time for which the supply of PFBA gas was stopped. [Figure 10] FIG. 10 is a graph showing the relationship between the atomic ratio of F to Ru determined from the XPS spectrum of the substrate surface obtained in Example 1 and the time period during which the supply of PFBA gas was stopped. [Figure 11] FIG. 11 is a graph showing the relationship between the water contact angle of the substrate surface obtained in Examples 4 to 6 and the time during which the supply of PFBA gas was stopped. [Figure 12] FIG. 12 is a diagram showing the water contact angles of the substrate surfaces obtained in Examples 7 to 13. [Figure 13] FIG. 13 is a diagram showing the water contact angles of the substrate surfaces obtained in Examples 14 to 20. 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 with reference to Figures 1 to 4. The film formation method includes, for example, steps S1 to S6 shown in Figure 1. Note that the film formation method may include at least steps S1, S3, and S4, and may not include, for example, steps S2, S5, and S6. Furthermore, the film formation method may include steps other than steps S1 to S6 shown in Figure 1.

[0010] 1 includes preparing a substrate 1 as shown in FIG. 2A. The substrate 1 includes a base substrate (not shown). The base substrate is, for example, a silicon wafer, a compound semiconductor wafer, or a glass substrate.

[0011] The substrate 1 has an insulating film 11 and a conductive film 12 in different regions of its surface 1a. The surface 1a of the substrate is, for example, the upper surface of the substrate 1. The insulating film 11 and the conductive film 12 are formed on an underlying substrate. Another functional film may be formed between the underlying substrate and the insulating film 11, or between the underlying substrate 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.

[0012] 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 is, 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 not limited to 1:1. The same applies to the SiN film, the SiOC film, the SiON film, and the SiOCN film. The insulating film 11 has a recess in the substrate surface 1a. The recess is a trench, a contact hole, or a via hole.

[0013] 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, or a W film. The conductive film 12 may also be a cap film. That is, a second conductive film (not shown) may be embedded in the recesses in the insulating film 11, and the second conductive film may be covered by the conductive film 12. The second conductive film is formed of a metal different from that of the conductive film 12.

[0014] Although not shown, the substrate 1 may further have a third film on the substrate surface 1a. The third film is, for example, a barrier film. The barrier film 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 is not particularly limited, but may be, for example, a TaN film or a TiN film. Here, the TaN film means a film containing tantalum (Ta) and nitrogen (N). The atomic ratio of Ta to N in the TaN film is not limited to 1:1. The same applies to the TiN film.

[0015] Although not shown, the substrate 1 may further have a fourth film on the substrate surface 1a. The fourth film is, for example, a liner film. The liner film is formed between the conductive film 12 and the barrier film. The liner film is formed on the barrier film and supports the formation of the conductive film 12. The conductive film 12 is formed on the liner film. The liner film is not particularly limited, but is, for example, a Co film or a Ru film.

[0016] Step S2 in FIG. 1 includes cleaning the substrate surface 1a. Contaminants (not shown) present on the substrate surface 1a can be removed. The contaminants include, for example, at least one of metal oxides and organic substances. The metal oxides are oxides formed, for example, by a reaction between the conductive film 12 and the atmosphere, and are so-called native oxide films. The organic substances are, for example, deposits containing carbon, which adhere to the substrate 1 during processing. Cleaning of the substrate surface 1a may be performed by either a dry process or a wet process.

[0017] For example, step S2 includes supplying a cleaning gas to the substrate surface 1a. The cleaning gas may be plasmatized to improve the efficiency of contaminant removal. The cleaning gas includes a reducing gas, such as H2 gas. The reducing gas can remove both metal oxides and organic substances.

[0018] An example of the processing conditions in step S2 is shown below. H2 gas flow rate: 200sccm to 10,000sccm Ar gas flow rate: 20sccm to 2000sccm Power supply frequency for plasma generation: 400kHz to 40MHz Plasma generation power: 50W~1000W Processing time: 10 seconds to 10 minutes Processing temperature (substrate temperature): 100℃~250℃ Processing pressure: 100Pa~2000Pa.

[0019] Step S3 in FIG. 1 modifies the substrate surface 1a, as shown in FIG. 2(B). For example, step S3 modifies the substrate surface 1a by supplying a plasma-converted modifying gas to the substrate surface 1a. The modifying gas contains hydrogen and oxygen, which can impart OH groups to the surface of the conductive film 12 and cause a dehydration condensation reaction with carboxy groups (COOH groups) in step S4, which will be described later. The modifying gas is, for example, HO gas, a mixed gas of H and O, or a mixed gas of H and O.

[0020] An example of the processing conditions in step S3 is shown below. H2O gas flow rate: 20sccm to 1000sccm Ar gas flow rate: 0sccm to 2000sccm Power supply frequency for plasma generation: 400kHz to 40MHz Plasma generation power: 50W~1000W Processing time: 10 seconds to 10 minutes Processing temperature (substrate temperature): 100℃~250℃ Processing pressure: 100Pa~2000Pa.

[0021] 1 includes selectively forming a SAM 17 on the surface of the conductive film 12 relative to the surface of the insulating film 11, as shown in FIG. 2(C). Step S4 includes steps S41 to S42 shown in FIG. 3. Steps S41 to S42 are performed with the substrate 1 accommodated in a processing vessel (e.g., processing vessel 210 in FIG. 7) and the pressure inside the processing vessel reduced. Note that the order of steps S41 and S42 may be reversed.

[0022] Step S41 includes supplying a carboxylic acid gas, which is a precursor of SAM 17, into the processing chamber. The carboxylic acid contains a carboxyl group (COOH group) and is represented by the general formula "R-COOH." 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.

[0023] Carboxylic acids include, for example, CF3(CF2)2COOH, CF3COOH, C6H5COOH, and CH3(CH2)n It contains at least one selected from the group consisting of COOH (n is an integer of 2 to 10). Hereinafter, CF3(CF2)2COOH will also be referred to as PFBA (Perfluorobutyric acid).

[0024] Carboxylic acid is more likely to be chemically adsorbed to the surface of the conductive film 12 than to the surface of the insulating film 11. According to this embodiment, since OH groups are added to the surface of the conductive film 12 in step S3, a dehydration condensation reaction between the OH groups and the COOH groups occurs, and SAM 17 is selectively formed on the surface of the conductive film 12.

[0025] Carboxylic acids are more likely to chemically adsorb to the Ru film surface than thiol compounds. Therefore, when the conductive film 12 is a Ru film, the density of the SAM 17 can be improved. Furthermore, carboxylic acids can form SAM 17 with superior high-temperature resistance compared to thiol compounds. Therefore, it is possible to set the processing temperature in step S6 (forming the target film), which will be described later, higher.

[0026] Step S42 includes stopping the supply of carboxylic acid gas into the processing vessel for a set time. The carboxylic acid remaining in the processing vessel is chemically adsorbed onto the surface of the conductive film 12. This improves the density of the SAM 17. It also improves the efficiency of using the carboxylic acid. The set time is, for example, 5 minutes to 1 hour, and preferably 30 minutes to 60 minutes.

[0027] In addition, step S42 may include maintaining a state in which the supply flow rate of the carboxylic acid gas into the processing vessel is reduced compared to step S41 for a set time, instead of maintaining a state in which the supply of the carboxylic acid gas into the processing vessel is stopped for a set time. This also improves the density of the SAM 17 and the use efficiency of the carboxylic acid.

[0028] Step S42 preferably includes stopping the supply of all gases into the processing vessel for a set time. This prevents the carboxylic acid remaining in the processing vessel from being diluted with other gases. This promotes the dehydration condensation reaction between the COOH groups and the OH groups, thereby improving the density of the SAM 17.

[0029] The pressure in the processing vessel in step S42 may be lower than the pressure in the processing vessel in step S41. Maintaining a low pressure can prevent a reverse reaction that occurs when HO generated in the dehydration condensation reaction reattaches to the SAM 17. In step S42, the opening of the pressure adjusting valve of the pressure controller (for example, the pressure controller 271 in FIG. 7) that controls the pressure inside the processing chamber is maintained constant.

[0030] Step S43 includes checking whether steps S41 to S42 have been performed a set number of times. If the number of times has not reached the set number (step S43, NO), the density of the SAM 17 is insufficient, so steps S41 to S42 are performed again. On the other hand, if the number of times has reached the set number of times (step S43, YES), the density of the SAM 17 is sufficient, so this processing ends.

[0031] The number of times step S43 is set may be once, but is preferably multiple times. By repeatedly supplying and stopping the supply of carboxylic acid, the supply of carboxylic acid can be dispersed, and the use efficiency of carboxylic acid can be further improved. The number of times step S43 is set is, for example, 2 to 15.

[0032] An example of the processing conditions in step S4 is shown below. Step S41 PFBA gas flow rate: 10sccm to 100sccm Processing time: 30 seconds to 10 minutes Processing pressure: 100Pa~300Pa Step S42 Processing time: 5 minutes to 1 hour Processing pressure: 10Pa to 100Pa Processing conditions common to steps S41 to S42 Processing temperature: 100℃~250℃.

[0033] 1 includes checking whether steps S3 to S4 have been performed a set number of times. If the number of times has not reached the set number (step S5, NO), the density of the SAM 17 is insufficient, so steps S3 to S4 are performed again. On the other hand, if the number of times has reached the set number of times (step S5, YES), the density of the SAM 17 is sufficient, so the current process is terminated.

[0034] The number of times step S5 is set may be one, but is preferably multiple. By repeatedly performing steps S3 and S4, OH groups can be replenished to the surface of conductive film 12 during the supply of carboxylic acid, and the dehydration condensation reaction between COOH groups of carboxylic acid and OH groups can be promoted. The number of times step S5 is set is, for example, 2 to 15.

[0035] 1 includes forming a target film 18 on the surface of the insulating film 11 while using the SAM 17 to inhibit the formation of the target film 18 on the surface of the conductive film 12, as shown in FIG. 2(D). The target film 18 is, for example, an insulating film, and is formed on the insulating film 11. According to this embodiment, the density of the SAM 17 is high, and therefore the blocking performance of the SAM 17 is good.

[0036] The target film 18 is not particularly limited, but may be, for example, an AlO film, a SiO film, a SiN film, a ZrO film, or a HfO film. Here, the AlO film means a film containing aluminum (Al) and oxygen (O). The atomic ratio of Al to O in the AlO film is not limited to 1:1. The same applies to the SiO film, the SiN film, the ZrO film, and the HfO film. The target film 18 is formed by a CVD (Chemical Vapor Deposition) method or an ALD (Atmospheric Layer Deposition) method.

[0037] When an AlO film is formed by the ALD method, an Al-containing gas such as TMA (trimethylaluminum) gas and an oxidizing gas such as water vapor (HO gas) are alternately supplied to the substrate surface 1a. The method for forming the AlO film includes, for example, steps S61 to S65 shown in FIG.

[0038] Step S61 includes supplying an Al-containing gas to the substrate surface 1a. Step S62 includes supplying an inert gas such as Ar gas to the substrate surface 1a and purging excess Al-containing gas that has not been adsorbed onto the substrate surface 1a. Step S63 includes supplying an oxidizing gas to the substrate surface 1a. Step S64 includes supplying an inert gas such as Ar gas to the substrate surface 1a and purging excess oxidizing gas that has not been adsorbed onto the substrate surface 1a. The order of steps S61 and S63 may be reversed.

[0039] Step S65 includes checking whether steps S61 to S64 have been performed a set number of times. If the number of times has not reached the set number (step S65, NO), steps S61 to S64 are performed again. On the other hand, if the number of times has reached the set number of times (step S65, YES), the thickness of the AlO film has reached the target thickness, so this processing ends. The set number of times of step S65 is set according to the target thickness of the AlO film, and is, for example, 20 to 80 times.

[0040] An example of the processing conditions in step S6 is shown below. Step S61 TMA gas flow rate: 50 sccm Processing time: 0.1 to 2 seconds Step S62 Ar gas flow rate: 1000sccm to 8000sccm Processing time: 0.5 to 2 seconds Step S63 H2O gas flow rate: 50sccm to 200sccm Processing time: 0.5 to 2 seconds Step S64 Ar gas flow rate: 1000sccm to 8000sccm Processing time: 0.5 to 5 seconds Processing conditions common to steps S61 to S64 Processing temperature: 100℃~250℃ Processing pressure: 133Pa~1200Pa.

[0041] Next, a film forming method according to a modified example will be described with reference to FIG. 5. Steps S1 to S2 of this modified example are similar to steps S1 to S2 of the above embodiment, and therefore will not be described again. Step S3 of this modified example modifies the substrate surface 1a, as shown in FIG. 5(A). The modifying gas contains hydrogen and nitrogen, which can impart NH groups to the surface of the conductive film 12, and can cause a dehydration condensation reaction with carboxy groups (COOH groups) in step S4, which will be described later. The modifying gas is, for example, a mixed gas of H2 and N2, or NH3 gas.

[0042] An example of the processing conditions in step S3 is shown below. H2 gas flow rate: 100sccm to 2000sccm N2 gas flow rate: 100sccm to 2000sccm Power supply frequency for plasma generation: 40MHz Power for plasma generation: 200W Processing time: 10 to 60 seconds Processing temperature (substrate temperature): 100℃~250℃ Processing pressure: 200Pa~2000Pa.

[0043] 5(B), step S4 of this modification includes selectively forming a SAM 17 on the surface of the conductive film 12 relative to the surface of the insulating film 11. Step S4 of this modification is similar to step S4 of the above embodiment except that the SAM 17 is formed by utilizing a dehydration condensation reaction between an NH group and a COOH group, and therefore a description thereof will be omitted.

[0044] Thereafter, steps S5 and S6 are performed. Step S5 is the same as step S5 in the above embodiment, and therefore its description will be omitted. Step S6 includes forming the target film 18 on the surface of the insulating film 11 while inhibiting the formation of the target film 18 on the surface of the conductive film 12 using the SAM 17, as shown in FIG. 5(C).

[0045] Next, with reference to FIG. 6, a film formation apparatus 100 for carrying out the above-described film formation method will be described. As shown in FIG. 6, 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 step S2 of FIG. 1. The second processing unit 200B performs step S3 of FIG. 1. The third processing unit 200C performs step S4 of FIG. 1. The fourth processing unit 200D performs step S6 of FIG. 1. The first processing unit 200A, the second processing unit 200B, the third processing unit 200C, and the fourth processing unit 200D have similar structures. Therefore, it is possible to carry out all of steps S2 to S4 and S6 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.

[0046] 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.

[0047] 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 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.

[0048] 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.

[0049] The control unit 500 is, for example, a computer, and includes a CPU (Central Processing Unit) 501 and a storage medium 502 such as a memory. The storage medium 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 CPU 501 to execute the programs stored in the storage medium 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 transport unit 400 to perform the above-described film forming method.

[0050] 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.

[0051] Next, first processing unit 200A performs step S2. 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 oxidation of substrate 1 can be suppressed.

[0052] Next, second processing unit 200B performs step S3. Thereafter, second transport mechanism 412 removes substrate 1 from second processing unit 200B and transports the removed substrate 1 to third processing unit 200C. During this time, the atmosphere around substrate 1 can be maintained at a vacuum atmosphere.

[0053] Next, third processing unit 200C performs step S4. Subsequently, control unit 500 checks whether steps S3 to S4 have been performed the set number of times. If the set number of times has not been reached, second transport mechanism 412 removes substrate 1 from third processing unit 200C and transports the removed substrate 1 to second processing unit 200B. Thereafter, control unit 500 controls second processing unit 200B, third processing unit 200C, and transport unit 400 to perform steps S3 to S4.

[0054] On the other hand, if the number of times has reached the set number, the second transport mechanism 412 removes the substrate 1 from the third processing unit 200C and transports the removed substrate 1 to the fourth processing unit 200D. During this time, the atmosphere around the substrate 1 can be maintained at a vacuum atmosphere, and a decrease in the blocking performance of the SAM 17 can be suppressed.

[0055] Next, fourth processing unit 200D performs step S6. Thereafter, second transport mechanism 412 removes substrate 1 from fourth processing unit 200D, transports the removed substrate 1 to load lock chamber 421, and exits from load lock chamber 421. Next, the internal atmosphere of load lock chamber 421 is switched from a vacuum atmosphere to an atmospheric atmosphere. Thereafter, first transport mechanism 402 removes substrate 1 from load lock chamber 421 and stores the removed substrate 1 in carrier C. Then, processing of substrate 1 is completed.

[0056] Next, first processing unit 200A will be described with reference to Fig. 7. Note that 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.

[0057] 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.

[0058] 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.

[0059] 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. 6) via the transfer port 215.

[0060] 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.

[0061] 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. 6), 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 .

[0062] 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.

[0063] A gas supply unit 240 is provided on a ceiling wall 217 of the processing vessel 210 via an insulating member 218. The gas supply unit 240 forms 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 400 kHz to 40 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 a capacitively coupled plasma, and may be one that generates other types of plasma, such as an inductively coupled plasma.

[0064] 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.

[0065] 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 S2 to S4 and S6 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 along the individual pipe, and a flow rate controller provided midway along 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.

[0066] [Experimental data] Next, we will explain the experimental data. The water contact angle was measured using an LSE-ME3 manufactured by NIC Co., Ltd. The water contact angle represents the density of the SAM. Since SAMs are hydrophobic, the larger the water contact angle, the higher the density of the SAM.

[0067] <Example 1> In Example 1, steps S1, S3, and S4 in FIG. 1 were performed. In step S1, a substrate having a Ru film formed on its surface by PVD (Physical Vapor Deposition) was prepared. In step S3, plasma-formed H2O gas was supplied to the substrate surface. The processing conditions for step S3 were as follows: H2O gas flow rate: 100sccm Ar gas flow rate: 900 sccm Power supply frequency for plasma generation: 40MHz Power for plasma generation: 200W Processing time: 1 minute Processing temperature (substrate temperature): 150°C Processing pressure: 266Pa.

[0068] In step S4, steps S41 and S42 shown in Fig. 3 were performed once each in this order. In step S41, a substrate was placed in a processing vessel, and PFBA gas was supplied into the processing vessel while the processing vessel was under reduced pressure. The processing conditions for step S41 were as follows: PFBA gas flow rate: 50 sccm Processing time: 5 minutes Processing temperature: 150℃ Processing pressure: 160Pa.

[0069] In step S42, the supply of PFBA gas into the processing vessel was stopped for a set time. The set time was 10 minutes (600 seconds), 20 minutes (1200 seconds), 30 minutes (1800 seconds), or 40 minutes (2400 seconds). The processing conditions for step S42 were as follows: Processing time: 10, 20, 30, or 40 minutes Processing temperature: 150℃ Processing pressure: 52Pa.

[0070] For comparison, an experiment was also conducted in which only step S41 was performed without performing step S42, that is, the set time for step S42 was set to zero.

[0071] <Example 2> In Example 2, the substrate surface was treated under the same conditions as in Example 1, except that step S3 was not performed.

[0072] <Example 3> In Example 3, the substrate surface was treated under the same conditions as in Example 1, except that plasma H2 gas was used instead of plasma H2O gas in step S3. The treatment conditions for step S3 were as follows: H2 gas flow rate: 2000sccm Ar gas flow rate: 3000 sccm Power supply frequency for plasma generation: 40MHz Power for plasma generation: 200W Processing time: 1 minute Processing temperature (substrate temperature): 150°C Processing pressure: 266Pa.

[0073] <Evaluation of the substrates obtained in Examples 1 to 3> Figure 8 shows the relationship between the water contact angle of the substrate surface obtained in Examples 1 to 3 and the time for which the supply of PFBA gas was stopped. Figure 8 shows that the water contact angle increases and the density of the SAM increases by supplying plasmatized HO gas to the Ru film surface, then supplying PFBA gas to the Ru film surface, and then stopping the supply of PFBA gas for 5 minutes (300 seconds) or more.

[0074] Figure 9 shows the relationship between the F peak in the XPS (X-ray photoelectron spectroscopy) spectrum of the substrate surface obtained in Example 1 and the time the supply of PFBA gas was stopped. In Figure 9, t represents the time the supply of PFBA gas was stopped. In Figure 9, "Initial" is the XPS spectrum of the Ru film surface before steps S3 and S4 were performed. From Figure 9, it can be seen that the longer the time the supply of PFBA gas was stopped, the higher the F peak and the higher the density of the SAM.

[0075] Figure 10 shows the relationship between the atomic ratio of F to Ru determined from the XPS (X-ray photoelectron spectroscopy) spectrum of the substrate surface obtained in Example 1 and the time the supply of PFBA gas was stopped. In Figure 10, the horizontal axis represents the time the supply of PFBA gas was stopped, and the vertical axis represents the atomic ratio of F to Ru (F / Ru). Figure 10 shows that the longer the time the supply of PFBA gas was stopped, the higher the atomic ratio of F to Ru and the higher the density of the SAM.

[0076] Table 1 shows the evaluation results of Examples 1 to 3.

[0077] [Table 1]

[0078] <Example 4> In Example 4, the substrate surface was treated under the same conditions as in Example 1, except that a substrate having a Ru film formed on its surface by CVD was prepared.

[0079] <Example 5> In Example 5, the substrate surface was treated under the same conditions as in Example 4, except that step S3 was not performed.

[0080] <Example 6> In Example 6, the substrate surface was treated under the same conditions as in Example 4, except that plasma H gas was used instead of plasma H O gas in step S3. The treatment conditions in step S3 were the same as those in Example 3.

[0081] <Evaluation of the substrates obtained in Examples 4 to 6> Figure 11 shows the relationship between the water contact angle of the substrate surface obtained in Examples 4 to 6 and the time the supply of PFBA gas was stopped. Figure 11 shows that the water contact angle increases and the density of the SAM increases by supplying plasmatized HO gas to the Ru film surface, then supplying PFBA gas to the Ru film surface, and then stopping the supply of PFBA gas for 5 minutes (300 seconds) or more.

[0082] Table 2 shows the evaluation results of Examples 4 to 6.

[0083] [Table 2]

[0084] <Examples 7 to 13> In Examples 7 to 13, the substrate surface (i.e., the surface of a Ru film formed by PVD) was treated in the same manner as in Example 1, except for the presence or absence of Step S3 and the treatment conditions. The presence or absence of Step S3 and the treatment conditions were as follows: In Example 7, H2 gas was supplied to the substrate surface in a plasma state; in Example 8, a mixed gas containing H2 gas and N2 gas was supplied to the substrate surface in a plasma state; in Example 9, O2 gas was supplied to the substrate surface in a plasma state; in Example 10, Step S3 was not performed; in Example 11, O3 gas generated by UV irradiation was supplied to the substrate surface without being turned into a plasma; in Example 12, O2 gas was supplied to the substrate surface without being turned into a plasma; and in Example 13, H2O gas was supplied to the substrate surface in a plasma state.

[0085] Figure 12 shows the water contact angles of the substrate surfaces obtained in Examples 7 to 13. Figure 12 shows that if, before supplying PFBA gas to the Ru film surface, H2O gas in a plasma state is supplied to the Ru film surface, or if a mixed gas containing H2 gas and N2 gas in a plasma state is supplied to the substrate surface, the water contact angle becomes higher and the SAM density becomes higher compared to when step S3 is not performed.

[0086] <Example 14 to Example 20> In Examples 14 to 20, the substrate surface (i.e., the surface of a Ru film formed by CVD) was treated in the same manner as in Example 4, except for the presence or absence of Step S3 and the treatment conditions. The presence or absence of Step S3 and the treatment conditions were as follows: In Example 14, H2 gas was supplied to the substrate surface in a plasma state; in Example 15, a mixed gas containing H2 gas and N2 gas was supplied to the substrate surface in a plasma state; in Example 16, O2 gas was supplied to the substrate surface in a plasma state; in Example 17, Step S3 was not performed; in Example 18, O3 gas generated by UV irradiation was supplied to the substrate surface without being turned into a plasma; in Example 19, O2 gas was supplied to the substrate surface without being turned into a plasma; and in Example 20, H2O gas was supplied to the substrate surface in a plasma state.

[0087] Fig. 13 shows the water contact angles of the substrate surfaces obtained in Examples 14 to 20. Fig. 13 shows that if, before supplying PFBA gas to the Ru film surface, H2O gas in a plasma state is supplied to the Ru film surface, or if a mixed gas containing H2 gas and N2 gas in a plasma state is supplied to the substrate surface, the water contact angle becomes higher and the SAM density becomes higher compared to when step S3 is not performed.

[0088] 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]

[0089] 1 board 1a Substrate surface 11 Insulating film (first film) 12 Conductive film (second film) 17 SAM (Self-assembled monolayer)

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) supplying a modifying gas in plasma form to the surface of the substrate to modify the surface of the substrate; (C) after (B), selectively forming a self-assembled monolayer on the surface of the second film relative to the surface of the first film; and The reforming gas used in (B) contains hydrogen and oxygen or hydrogen and nitrogen, (C) is a film forming method including: (Ca) supplying a carboxylic acid gas, which is a precursor of the self-assembled monolayer, into a processing vessel while the substrate is accommodated in the processing vessel and the processing vessel is under reduced pressure; and (Cb) maintaining, for a set time, a state in which the supply of the carboxylic acid gas into the processing vessel is stopped or a state in which the supply flow rate of the carboxylic acid gas is reduced compared to (Ca).

2. 2. The film forming method according to claim 1, wherein the set time for (Cb) is 5 minutes to 1 hour.

3. 3. The film forming method according to claim 1, wherein the step (Cb) includes maintaining a state in which all gases are stopped from being supplied into the processing chamber for the set time.

4. 4. The film forming method according to claim 1, wherein the pressure in the processing chamber at (Cb) is lower than the pressure in the processing chamber at (Ca).

5. 5. The film forming method according to claim 1, wherein the pressure inside the processing vessel in (Cb) is 10 Pa to 100 Pa.

6. 6. The film forming method according to claim 1, wherein the pressure inside the processing vessel in (Ca) is 100 Pa to 300 Pa.

7. The carboxylic acid used in (Ca) is CF ３ (CF ２ ) ２ COOH, C.F. ３ COOH, C ６ H ５ COOH, and CH ３ (CH ２ ) ｎ 7. The film forming method according to claim 1, wherein the film contains at least one selected from the group consisting of COOH (n is an integer of 2 to 10).

8. 8. The film forming method according to claim 1, wherein the step (C) includes repeatedly carrying out the steps (Ca) and (Cb).

9. The modifying gas used in (B) is H ２ O gas, H ２ and O ２ or H ２ and O ３ 9. The film forming method according to claim 1, wherein the mixed gas is a gas mixture of the above.

10. The gas used in (B) is H ２ and N ２ or NH ３ The film forming method according to any one of claims 1 to 8, wherein the gas is a gas.

11. The film forming method according to any one of claims 1 to 10, comprising repeatedly carrying out (B) and (C).

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

13. The film forming method according to claim 12 , wherein the conductive film is a Cu film, a Co film, a Ru film, or a W film.

14. The film forming method according to any one of claims 1 to 13, further comprising (D) cleaning the surface of the substrate before (B).

15. The film forming method according to claim 14 , wherein the step (D) includes supplying a reducing gas in plasma form to the surface of the substrate.

16. (E) after (C), forming a target film on the surface of the first film while inhibiting formation of the target film on the surface of the second film using the self-assembled monolayer.

17. A processing vessel; a holder that holds the substrate inside the processing vessel; a gas supply mechanism that supplies gas into the processing chamber; a gas exhaust mechanism that exhausts gas from the inside of the processing vessel; a transfer mechanism that transfers the substrate into and out of the processing chamber; a control unit that controls the gas supply mechanism, the gas exhaust mechanism, and the transport mechanism to perform the film formation method according to any one of claims 1 to 16; A film forming apparatus comprising:

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