Film forming method and film forming apparatus

Abstract

To provide a technique of improving selectivity in a region where a metal film is formed.SOLUTION: A deposition method contains following steps (A) to (C): a step (A) of preparing a substrate having a first film containing a boron and a second film formed by a material different from that of the first film on a front surface; a step (B) of supplying a material gas containing halogen and an element X of halogen to the front surface of the substrate; and a step (C) of supplying a reaction gas containing a plasma oxygen to the front surface of the substrate. By the deposition method, a third gild as an oxygen film of the element X is selectively formed on the second film toward the first film by alternately supplying the material gas and the plasma reaction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] The method for forming a nitride film described in Patent Document 1 includes a step of adsorbing chlorine gas onto the surfaces of a first base film and a second base film, and a step of selectively forming a nitride film on one of the first base film and the second base film that has adsorbed chlorine gas. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-174919 Summary of the Invention [Problem to be solved by the invention]

[0004] One aspect of the present disclosure provides a technique for selectively forming an oxide film on a second film made of a material different from that of a first film containing boron. [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, on its surface, a first film containing boron and a second film formed of a material different from the first film; (B) supplying a source gas containing a halogen and an element X other than a halogen to the surface of the substrate; and (C) supplying a reactive gas containing oxygen in plasma to the surface of the substrate. The film formation method alternates between supplying the source gas and supplying the reactive gas in plasma to selectively form a third film, which is an oxide film of the element X, on the second film relative to the first film. [Effects of the Invention]

[0006] According to one aspect of the present disclosure, an oxide film can be selectively formed on a second film made of a material different from that of a first film containing boron. [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 diagram showing a first example of the substrate prepared in S101. [Figure 3] FIG. 3 is a diagram showing a second example of the substrate prepared in S101. [Figure 4] FIG. 4 is a diagram showing a third example of the substrate prepared in S101. [Figure 5] FIG. 5 is a diagram showing a fourth example of the substrate prepared in S101. [Figure 6] FIG. 6 is a diagram showing a fifth example of the substrate prepared in S101. [Figure 7] FIG. 7 is a diagram showing a sixth example of the substrate prepared in S101. [Figure 8] FIG. 8 is a diagram showing a seventh example of the substrate prepared in S101. [Figure 9] FIG. 9 is a flowchart showing an example of S201 to S205 performed in S101. [Figure 10] FIG. 10 is a diagram showing an eighth example of the substrate prepared in S101. [Figure 11] FIG. 11 is a cross-sectional view showing a film forming apparatus according to an embodiment. [Figure 12] FIG. 12 is an SEM photograph showing the substrate of Example 1 before treatment. [Figure 13] FIG. 13 is an SEM photograph showing the substrate after processing in Example 1. [Figure 14] FIG. 14 is an SEM photograph showing the substrate of Example 9 before treatment. [Figure 15] FIG. 15 is an SEM photograph showing the substrate after processing in Example 9. [Figure 16] FIG. 16 is an SEM photograph showing the substrate of Example 13 before treatment. [Figure 17] FIG. 17 is an SEM photograph showing the substrate of Example 13 after processing. [Figure 18] FIG. 18 is an SEM photograph showing the substrate of Example 14 before treatment. [Figure 19] FIG. 19 is an SEM photograph showing the substrate of Example 14 after processing. [Figure 20] FIG. 20 is a flowchart showing a film forming method according to a modified example. [Figure 21] FIG. 21 is a flowchart showing the procedure when K is an integer equal to or greater than 2 in FIG. [Figure 22] FIG. 22 is a diagram illustrating an example of the processing of FIG. [Figure 23] FIG. 23 is a diagram illustrating another example of the process of FIG. [Figure 24] FIG. 24 is a diagram showing a ninth example of the substrate prepared in S101. [Figure 25] FIG. 25 is a diagram showing a tenth example of the substrate prepared in S101. [Figure 26] FIG. 26 is an SEM photograph showing the substrate of Example 15 before treatment. [Figure 27] FIG. 27 is an SEM photograph showing the substrate after processing in Example 15. [Figure 28] FIG. 28 is an SEM photograph showing the substrate of Example 16 before treatment. [Figure 29] FIG. 29 is an SEM photograph showing the substrate after processing in Example 16. [Figure 30] FIG. 30 is an SEM photograph showing the substrate of Example 17 before treatment. [Figure 31] FIG. 31 is an SEM photograph showing the substrate of Example 17 after processing. [Figure 32] FIG. 32 is a flowchart showing a film forming method according to the second modified example. [Figure 33] FIG. 33 is an SEM photograph showing the substrate of Example 5 before treatment. [Figure 34] FIG. 34 is an SEM photograph showing the substrate after processing in Example 5. 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] First, a film formation method according to one embodiment will be described with reference to Fig. 1. The film formation method includes, for example, steps S101 to S106 shown in Fig. 1. Note that the film formation method only needs to include at least steps S101, S102, and S104. The order of steps S102 and S104 may be reversed, or step S104 may be performed before step S102. The film formation method may include steps other than steps S101 to S106 shown in Fig. 1.

[0010] Step S101 in FIG. 1 includes preparing a substrate W (see FIG. 2). The substrate W has a first film W1 and a second film W2 on its surface Wa. The first film W1 and the second film W2 are formed on, for example, an underlying substrate (not shown). The underlying substrate is a silicon wafer or a compound semiconductor wafer. The compound semiconductor wafer is, for example, a GaAs wafer, a SiC wafer, a GaN wafer, or an InP wafer.

[0011] The first film W1 contains boron (B). The B content in the first film W1 is, for example, 20 atomic % to 100 atomic %, and preferably 40 atomic % to 100 atomic %. The first film W1 is, for example, a B film, a BN film, a BNC film, a BO film, a BNOC film, a SiBN film, a SiBCN film, or a SiOBN film. Here, a BN film means a film containing boron (B) and nitrogen (N). The atomic ratio of B to N in a BN film is not limited to 1:1. BNC films other than a BN film also mean that they contain the respective elements and are not limited to a stoichiometric ratio.

[0012] The second film W2 is formed of a material different from that of the first film W1. The second film W2 does not substantially contain B. "Substantially not containing B" means that the B content is 0 atomic % to 5 atomic %. The lower the B content in the second film W2, the more preferable it is. The second film W2 may be any of an insulating film, a conductive film, and a semiconductor film.

[0013] The insulating film is not particularly limited, but may be, for example, an SiO film, a SiN film, a SiOC film, a SiON film, a SiOCN film, an AlO film, a ZrO film, a HfO film, or a TiO 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, a SiOC film, a SiON film, a SiOCN film, an AlO film, a ZrO film, a HfO film, and a TiO film also mean that they contain the respective elements and are not limited to the stoichiometric ratio. The insulating film is, for example, an interlayer insulating film. The interlayer insulating film is preferably a low dielectric constant (Low-k) film.

[0014] The semiconductor film is not particularly limited, but may be, for example, a Si film, a SiGe film, or a GaN film. The semiconductor film may be any of a single crystal film, a polycrystalline film, and an amorphous film.

[0015] The conductive film is, for example, a metal film. The metal film is not particularly limited, but is, for example, a Cu film, a Co film, a Ru film, a Mo film, a W film, or a Ti film. The conductive film may be a metal nitride film. The metal nitride film is not particularly limited, but is, for example, a TiN film or a TaN film. Here, the TiN film means 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 means that it contains each element and is not limited to a stoichiometric ratio.

[0016] Step S102 in FIG. 1 includes supplying a source gas to the surface Wa of the substrate W. The source gas contains a halogen and an element X other than a halogen. The halogen is fluorine, chlorine, bromine, or iodine. The element X is not particularly limited as long as it is oxidized in step S104, but is preferably a metal element, more preferably a transition metal element. Examples of the transition metal element include Ti, W, V, Al, Mo, Sn, and Hf. Specific examples of the source gas include TiCl4 gas, WCl6 gas, VCl4 gas, AlCl3 gas, MoCl5 gas, SnCl4 gas, and HfCl4 gas. The element X may be a semiconductor element, specifically, Si or Ge. The source gas is a silicon halide gas or a germanium halide gas. Specific examples of the silicon halide gas include SiCl4 gas, SiHCl3 gas, SiH2Cl2 gas, SiH3Cl gas, and Si2Cl6 gas. 、 Examples of the germanium halide gas include Si2HCl5 gas, SiH2I2 gas, and SiCl3CH3 gas. A specific example of the germanium halide gas is GeCl4 gas. The source gas may be supplied together with a dilution gas. The dilution gas is, for example, Ar gas or N2 gas.

[0017] 1 includes supplying a purge gas to the surface Wa of the substrate W. The purge gas purges excess source gas that was not adsorbed onto the surface Wa of the substrate W in step S102. As the purge gas, for example, a rare gas such as Ar gas or N gas is used.

[0018] Step S104 in FIG. 1 includes supplying a reactive gas to the surface Wa of the substrate W. Step S104 includes plasmatizing the reactive gas and supplying the plasmatized reactive gas to the surface Wa of the substrate W. The reactive gas contains oxygen and oxidizes element X contained in the adsorbed source gas to form a third film W3, which is an oxide film of element X (see FIG. 2). The reactive gas is, for example, O2 gas, O3 gas, CO2 gas, N2O gas, NO gas, or H2O gas. The reactive gas may be supplied together with a dilution gas. The dilution gas is, for example, Ar gas or N2 gas.

[0019] The reactive gas may be supplied not only in step S104 but also in all of steps S102 to S105. However, the reactive gas is turned into plasma only in step S104. This is because the reactive gas becomes more likely to react with the source gas adsorbed on the surface Wa of the substrate W when turned into plasma.

[0020] 1 includes supplying a purge gas to the surface Wa of the substrate W. The purge gas purges excess reactive gas that did not react with the surface Wa of the substrate W in step S104. As the purge gas, for example, a rare gas such as Ar gas or N gas is used.

[0021] 1, it is confirmed whether or not the above steps S102 to S105 have been performed N times (N is an integer of 1 or more). N may be an integer of 2 or more, and the above steps S102 to S105 may be performed repeatedly. This allows the thickness of the third film W3 to be increased.

[0022] If the number of times steps S102 to S105 have been performed is less than N (step S106, NO), the thickness of the third film W3 is less than the target value, so steps S102 to S105 are performed again. N is preferably 200 or more, and more preferably 300 or more. N is preferably 1000 or less.

[0023] On the other hand, if the number of times steps S102 to S105 have been performed reaches N (step S106, YES), the film thickness of the third film W3 has reached the target value, and therefore the current processing is ended.

[0024] According to this embodiment, a third film W3 is selectively formed on the second film W2 relative to the first film W1 by a plasma ALD (Atomic Layer Deposition) method. To selectively form the third film W3, it is important that the adsorption of the source gas to the first film W1 is weak and that the source gas adsorbed on the first film W1 is desorbed without proceeding with the film-forming reaction (formation of the third film W3) due to collision or reaction with the plasmatized reactive gas.

[0025] The ease of desorption of the source gas adsorbed on the first film W1 varies depending on the strength of adsorption of the source gas to the first film W1, and on the material of the first film W1. The ease of desorption of the source gas adsorbed on the first film W1 also varies depending on whether the source gas is dissociated by reaction with atoms on the surface of the first film W1 and becomes molecules that are easily oxidized in subsequent reactions. It is thought that on the first film W1 containing boron, the adsorption of the halide source gas is weaker or does not occur, or the dissociation of the halide is more difficult to occur, compared to on the second film W2 that does not substantially contain boron.

[0026] By converting a reactive gas containing oxygen into plasma, oxygen ions or oxygen radicals are generated. The oxygen ions are accelerated by the potential of the plasma and collide with the substrate W. It is thought that the collision of the accelerated oxygen ions or oxygen radicals physically knocks away material on the surface Wa, resulting in sputtering. Alternatively, it is thought that the oxygen ions or oxygen radicals chemically react with material on the surface Wa to form a film.

[0027] Halides adsorbed on the second film W2, which contains substantially no boron, are either strongly adsorbed or dissociated into easily oxidizable molecules, and are easily oxidized by collisions with oxygen ions or oxygen radicals. Therefore, it is believed that oxide film formation proceeds on the second film W2. On the other hand, halides adsorbed on the first film W1, which contains boron, are either weakly adsorbed or not dissociated into easily oxidizable molecules, and are therefore knocked off by collisions with oxygen ions or oxygen radicals. Therefore, it is believed that oxide film formation does not proceed on the first film W1.

[0028] Possible reasons why the formation of an oxide film on the first film W1 does not progress include the detachment of halides by sputtering or chemical reaction, or the etching of the first film W1 by collision with oxygen ions or oxygen radicals, resulting in the lift-off of halides.

[0029] As shown in FIG. 32, step S109 may be performed instead of step S104. Step S109 includes supplying O3 gas to the surface Wa of the substrate W without converting it into plasma. Because the O3 gas is supplied without converting it into plasma, it does not initially contain oxygen ions or oxygen radicals. When the O3 gas collides with the surface Wa of the heated substrate W, it generates oxygen radicals. The oxygen radicals oxidize the halides adsorbed on the second film W2, which contains substantially no boron, and the formation of an oxide film progresses. On the other hand, the halides adsorbed on the first film W1, which contains boron, are knocked away, preventing the formation of an oxide film.

[0030] In addition, when a reactive gas that does not contain oxygen, such as H2 gas or NH3 gas, is converted into plasma, active species such as ions or radicals are also generated, and these active species tend to promote the film formation reaction. Therefore, if a reactive gas that does not contain oxygen is used, the film formation reaction tends to proceed not only on the second film W2 but also on the first film W1, which is thought to impair selectivity. Therefore, an oxygen-containing gas is suitable as the gas to be converted into plasma.

[0031] Furthermore, halides adsorbed on the first film W1 are less likely to be decomposed by collisions with oxygen ions or oxygen radicals. For example, halides such as TiCl4 are less likely to be decomposed by collisions with oxygen ions or oxygen radicals than organometallic complexes such as Ti[N(CH3)2]4. To desorb halides adsorbed on the first film W1 from the first film W1, it is important that they are less likely to be decomposed by collisions with oxygen ions or oxygen radicals or by heat from the substrate. Therefore, a gas containing a halogen is suitable as the source gas.

[0032] Furthermore, in the plasma CVD (Chemical Vapor Deposition) method, which converts both halide and oxygen into plasma, active species such as ions or radicals are generated when the halide dissociates, in addition to oxygen ions or oxygen radicals. The active species generated from the halide are highly reactive, and the film formation reaction is likely to proceed not only on the second film W2 but also on the first film W1, which is thought to impair selectivity. To achieve selectivity, it is important to use the plasma ALD method.

[0033] In steps S102 to S105, the temperature of the substrate W may be controlled to 100°C or higher to promote desorption of the source gas from the first film W1. If the temperature of the substrate W is lower than 100°C, the source gas will not be sufficiently desorbed from the first film W1 and will be physically adsorbed, resulting in the formation of a third film W3 over the entire surface Wa of the substrate W. The temperature of the substrate W is preferably 300°C or higher. The temperature of the substrate W is preferably 800°C or lower.

[0034] Next, with reference to FIGS. 3 to 5, a case will be described in which the substrate W prepared in step S101 has a recess Wa1 on its surface Wa, and the second film W2 is exposed only inside the recess Wa1. As shown in FIGS. 3 to 5, the second film W2 is exposed at least at the bottom surface of the recess Wa1. In this case, by performing steps S102 to S106, the third film W3 can be filled inside the recess Wa1. Note that in FIGS. 3 to 5, the third film W3 fills a portion of the recess Wa1, but it may also fill the entire recess Wa1. In the latter case, in FIG. 5, the first film W1 may be left only on the top surfaces of the convex portions of the second film W2 by etching.

[0035] 3, first, the first film W1 is formed on the entire surface of the second film W2, and then a portion of the surface of the first film W1 is etched. As a result, a recess Wa1 is formed through a portion of the first film W1, and the second film W2 is exposed only at the bottom of the recess Wa1. Then, by performing steps S102 to S106, the third film W3 is grown only at the bottom of the recess Wa1.

[0036] In step S101 of FIG. 4, first, a portion of the surface of the second film W2 is etched to form a recess in the surface of the second film W2. Next, a first film W1 is formed to fill the recess. Next, the first film W1 is processed by CMP (Chemical Mechanical Polishing) or etching until the second film W2 is exposed. Finally, the second film W2 is selectively etched relative to the first film W1. As a result, a recess Wa1 is formed penetrating a portion of the first film W1, and the second film W2 is exposed only at the bottom of the recess Wa1. Thereafter, steps S102 to S106 are performed, whereby a third film W3 is grown only at the bottom of the recess Wa1.

[0037] In step S101 of FIG. 5, first, a portion of the surface of the second film W2 is etched to form a recess in the surface of the second film W2. Next, a first film W1 is selectively formed on the outside of the recess (i.e., the top surface of the convex portion) relative to the inside of the recess. As a result, the second film W2 is exposed on the bottom surface and lower portions of the side surfaces of the recess Wa1. Note that if the first film W1 is also deposited on the bottom surface of the recess Wa1 during step S101, the first film W1 deposited on the bottom surface is removed by etching or the like. Thereafter, steps S102 to S106 are performed, whereby a third film W3 is grown on the bottom surface and lower portions of the side surfaces of the recess Wa1.

[0038] 6 to 8, a case will be described in which the substrate W prepared in step S101 has a recess Wa1 on its surface Wa, and the first film W1 is exposed only inside the recess Wa1. As shown in FIGS. 6 to 8, the first film W1 is exposed at least on the bottom surface of the recess Wa1. In this case, by performing steps S102 to S106, the third film W3 can be formed in areas other than the bottom surface of the recess Wa1.

[0039] 6, first, the second film W2 is formed over the entire surface of the first film W1, and then a portion of the surface of the second film W2 is etched. As a result, a recess Wa1 is formed penetrating a portion of the second film W2, and the first film W1 is exposed only at the bottom of the recess Wa1. Then, by performing steps S102 to S106, the third film W3 grows on the side surface of the recess Wa1 and outside the recess Wa1 (on the top surface of the convex portion).

[0040] In step S101 of FIG. 7, first, a portion of the surface of the first film W1 is etched to form a recess in the surface of the first film W1. Next, a second film W2 is formed to fill the recess. Next, the second film W2 is processed by CMP (Chemical Mechanical Polishing) or etching until the first film W1 is exposed. Finally, the first film W1 is selectively etched with respect to the second film W2. As a result, a recess Wa1 is formed penetrating a portion of the second film W2, and the first film W1 is exposed only at the bottom of the recess Wa1. Then, steps S102 to S106 are performed, whereby a third film W3 grows on the side surface of the recess Wa1 and outside the recess Wa1 (on the top surface of the convex portion).

[0041] In step S101 of FIG. 8, first, a portion of the surface of the first film W1 is etched to form a recess on the surface of the first film W1. Next, a second film W2 is selectively formed on the outside of the recess (i.e., the top surfaces of the convex portions) relative to the inside of the recess. As a result, the first film W1 is exposed at the bottom and lower portions of the side surfaces of the recess Wa1. Note that if the second film W2 also deposits on the bottom surface of the recess Wa1 during step S101, the second film W2 deposited on the bottom surface is removed by etching or the like. Then, steps S102 to S106 are performed, whereby a third film W3 grows on the outside of the recess Wa1 (i.e., the top surfaces of the convex portions) and on the upper portions of the side surfaces of the recess Wa1. The third film W3 may encapsulate voids (air gaps) inside the recess Wa1, as shown in FIG. 8.

[0042] 9 and 10, a modified example of step S101 will be described. Step S101 may include selectively forming a first film W1 on a fourth film W4 formed of a material different from that of the second film W2, as shown in Fig. 10. The first film W1 contains boron as described above.

[0043] The fourth film W4 may be any film that allows the first film W1 to be selectively formed on the fourth film W4 relative to the second film W2, and may be an insulating film, a conductive film, or a semiconductor film. For example, the incubation time of the first film W1 relative to the second film W2 may be longer than the incubation time of the first film W1 relative to the fourth film W4. This difference in incubation time can be used to selectively form the first film W1.

[0044] The incubation time is the time lag from the start of the film formation process (for example, the start of supplying a source gas or a reactive gas) to the actual start of film formation.

[0045] 9. Step S101 may include at least steps S201 and S203. The order of steps S201 and S203 may be reversed, or step S203 may be performed before step S201. Steps S201 and S203 may be performed simultaneously, or a CVD method may be used.

[0046] Step S201 in FIG. 9 includes supplying a second source gas to the surface of the substrate W. The second source gas contains boron. The second source gas is, for example, trisdimethylaminoborane (TDMAB: CH 18 The second source gas may be supplied together with a diluent gas, such as Ar gas or N2 gas.

[0047] The second source gas is not limited to one containing TDMAB, but may be any gas containing boron. For example, diborane (B2H6), boron trichloride (BCl3), boron trifluoride (BF3), trisethylmethylaminoborane (CH9H6), or the like may be used. 24 BN3), trimethylborane (C3H9B), or triethylborane (C6H 15 B), cyclotriborazane (B3N3H6), etc.

[0048] 9 includes supplying a purge gas to the surface of the substrate W. The purge gas purges excess second source gas that was not adsorbed on the surface Wa of the substrate W in step S201. As the purge gas, for example, a rare gas such as Ar gas or N gas is used.

[0049] Step S203 in FIG. 9 includes supplying a second reactive gas to the surface of the substrate W. The second reactive gas contains, for example, nitrogen, and forms a first film W1 (e.g., a BN film) by nitriding the adsorbed second source gas. The second reactive gas contains, for example, a mixed gas of N2 gas and H2 gas, or NH3 gas. The second reactive gas may be supplied together with a dilution gas. The dilution gas is, for example, Ar gas or N2 gas.

[0050] The second reactive gas may contain at least one of a nitrogen-containing gas, an oxygen-containing gas, and a reducing gas. The nitrogen-containing gas forms a boron nitride film by nitriding the second source gas. The nitrogen-containing gas includes, for example, NH3, N2, N2H4, or N2H2. The oxygen-containing gas forms a boron oxide film by oxidizing the second source gas. The oxygen-containing gas includes, for example, O2, O3, H2O, NO, or N2O. The reducing gas forms a boron film by reducing the second source gas. The reducing gas includes, for example, H2 or SiH4.

[0051] Step S203 may include converting the second reactive gas into plasma, and may include supplying the plasmatized second reactive gas to the surface Wa of the substrate W. Converting the second reactive gas into plasma can promote the formation of the first film W1.

[0052] The second reactive gas may be supplied not only in step S203 but also in all of steps S201 to S204. However, the second reactive gas is turned into plasma only in step S203. This is because turning the second reactive gas into plasma promotes the reaction between the second reactive gas and the second source gas adsorbed on the surface of the substrate W.

[0053] 9 includes supplying a purge gas to the surface of the substrate W. The purge gas purges excess second reactive gas that did not react with the surface Wa of the substrate W in step S203. As the purge gas, for example, a rare gas such as Ar gas or N gas is used.

[0054] 9, it is confirmed whether or not the above steps S201 to S204 have been performed M times (M is an integer of 1 or more). M may be an integer of 2 or more, and the above steps S201 to S204 may be performed repeatedly. This allows the thickness of the first film W1 to be increased.

[0055] If the number of times steps S201 to S204 have been performed is less than M (step S205, NO), the thickness of the first film W1 is less than the target value, so steps S201 to S204 are performed again. The target value for the thickness of the first film W1 is preferably 300 Å or less, more preferably 100 Å or less, and even more preferably 50 Å or less. A thickness of about 5 Å may also be acceptable.

[0056] On the other hand, if the number of times steps S201 to S204 have been performed reaches M (step S205, YES), the film thickness of the first film W1 has reached the target value, and therefore the current processing is ended.

[0057] 9 is formed by the ALD method, but may be formed by the CVD method. In the ALD method, the second source gas and the second reactive gas are alternately supplied. On the other hand, in the CVD method, the second source gas and the second reactive gas are simultaneously supplied.

[0058] The first film W1 may be a molecular film in which molecules are chemically adsorbed, such as a self-assembled monolayer (SAM). The molecules are supplied to the substrate surface in a gaseous or liquid state. The molecules have a first functional group that selectively chemically adsorbs to a desired region on the substrate surface. The first functional group is not particularly limited, but may be, for example, a thiol group (SH group), a carboxyl group (COOH group), or a hydroxyl group (OH group). In addition to the first functional group, the molecule includes a second functional group containing B. The second functional group is a functional group in which at least a portion of the carbon atoms in a hydrocarbon group are substituted with boron (B), such as BH3 or B(CH3)3. The first film W1 may be a molecular film obtained by thermal decomposition.

[0059] Next, a film forming method according to a modified example will be described with reference to Fig. 20. As shown in Fig. 20, the film forming method according to this modified example includes step 301, steps S201 to S205, steps S102 to S106, and step S302.

[0060] 20 are the same as steps S201 to S205 in Fig. 9, and therefore description thereof will be omitted. Note that the film forming method does not necessarily have all of steps S201 to S205. It is sufficient if the first film W1 can be selectively formed in a desired region.

[0061] 20 are the same as steps S102 to S106 in Fig. 1, and therefore will not be described. Note that the film forming method does not necessarily have all of steps S102 to S106. It is sufficient if the third film W3 can be selectively formed in a desired region.

[0062] Step S301 includes preparing a substrate W having a second film W2 and a fourth film W4 on its surface Wa (see FIG. 22). Then, steps S201 to S205 are performed to selectively form a first film W1 on the fourth film W4 relative to the second film W2. Then, steps S102 to S106 are performed to selectively form a third film W3 on the second film W2 relative to the first film W1.

[0063] Step S302 includes checking whether a series of processes has been performed K times (K is an integer greater than or equal to 1). The series of processes includes performing steps S201 to S204 M times (M is an integer greater than or equal to 1) and performing steps S102 to S105 N times (N is an integer greater than or equal to 1).

[0064] If the number of times the process has been performed is less than K (step S302, NO), the thickness of the third film W3 is insufficient, so the control unit 100 performs the series of processes again. On the other hand, if the number of times the process has been performed reaches K (step S302, YES), the control unit 100 ends the current process. K is preferably an integer of 2 or greater. If K is an integer of 2 or greater, the thickness of the third film W3 can be increased while the first film W1 is being replenished.

[0065] Next, a film formation method in which K is an integer equal to or greater than 2 will be described with reference to Figures 21 to 23. As shown in Figure 21, the film formation method may include steps S401 to S405. In Figure 21, L is equal to (K-1).

[0066] Similar to step S301, step S401 includes preparing a substrate W having a second film W2 and a fourth film W4 on its surface Wa (see FIG. 22). The fourth film W4 may be any film that allows the first film W1 to be selectively formed on the fourth film W4 relative to the second film W2. For example, the incubation time of the first film W1 relative to the second film W2 may be longer than the incubation time of the first film W1 relative to the fourth film W4.

[0067] Step S402 includes selectively forming the first film W1 on the fourth film W4 relative to the second film W2 (see FIG. 22). Step S402 includes performing steps S201 to S204 M times, where M is an integer equal to or greater than 1. M may also be an integer equal to or greater than 2.

[0068] Step S403 includes selectively forming a third film W3 on the second film W2 relative to the first film W1 (see FIG. 22). Step S403 includes performing steps S102 to S105 N times, where N is an integer equal to or greater than 1. N may also be an integer equal to or greater than 2.

[0069] Step S404 includes selectively forming the first film W1 again on the first film W1 with respect to the third film W3 (see FIG. 22). Like step S402, step S404 includes performing steps S201 to S204 M times.

[0070] In the process of forming the third film W3 in step S403, the first film W1 may become thin and may disappear (see FIG. 23). If the first film W1 disappears, step S404 includes selectively forming the first film W1 again on the fourth film W4 instead of the first film W1 (see FIG. 23).

[0071] Step S405 includes selectively forming the third film W3 again on the third film W3 with respect to the first film W1. Like step S403, step S405 includes performing steps S102 to S105 N times.

[0072] Step S406 includes checking whether steps S404 to S405 have been performed L (L=(K-1)) times. If the number of times has been less than L (step S406, NO), the control unit 100 performs steps S404 to S405 again. On the other hand, if the number of times has reached L (step S406, YES), the control unit 100 ends this processing.

[0073] Next, another variation of step S101 will be described with reference to FIG. 24. In step S101 of FIG. 24, first, a second film W2 having a concave-convex pattern is prepared. Next, a first film W1 is formed over the entire second film W2 by ALD or CVD, following the concave-convex pattern of the second film W2. Next, the top surfaces of the convex portions of the second film W2 are exposed by CMP or etching. At this time, the first film W1 remains on the side and bottom surfaces of the concave portions of the second film W2. Thereafter, steps S102 to S106 are performed, thereby forming a third film W3 on the top surfaces of the convex portions.

[0074] Next, with reference to FIG. 25, another variation of step S101 will be described. In step S101 of FIG. 25, a second film W2 having a concave-convex pattern is first prepared. Next, a first film W1 is formed to fill the recesses of the second film W2. The first film W1 is a liquid. The liquid is, for example, formed by polymerizing B-containing molecules having organic ligands such as TDMAB using N plasma or the like. Next, the liquid filling the recesses of the second film W2 is decomposed using O plasma or the like, leaving the first film W1 on the side and bottom surfaces of the recesses of the second film W2. The top surfaces of the convex portions of the second film W2 remain exposed. Although not shown, the liquid filling the recesses of the second film W2 may be modified using H plasma or the like to form the first film W1 filling the recesses of the second film W2. Then, steps S102 to S106 are performed to form a third film W3 on the top surfaces of the convex portions.

[0075] Next, a film forming apparatus 1 will be described with reference to Fig. 11. The film forming apparatus 1 includes a substantially cylindrical airtight processing chamber 2. An exhaust chamber 21 is provided in the center of the bottom wall of the processing chamber 2. The exhaust chamber 21 has, for example, a substantially cylindrical shape that protrudes downward. An exhaust pipe 22 is connected to the exhaust chamber 21, for example, at a side surface of the exhaust chamber 21.

[0076] An exhaust unit 24 is connected to the exhaust pipe 22 via a pressure adjustment unit 23. The pressure adjustment unit 23 includes a pressure adjustment valve such as a butterfly valve. The exhaust pipe 22 is configured so that the pressure inside the processing vessel 2 can be reduced by the exhaust unit 24. A transfer port 25 is provided on the side of the processing vessel 2. The transfer port 25 is opened and closed by a gate valve 26. The substrate W is loaded and unloaded between the processing vessel 2 and a transfer chamber (not shown) via the transfer port 25.

[0077] A stage 3 is provided within the processing vessel 2. The stage 3 is a holder that holds the substrate W horizontally with its surface Wa facing upward. The stage 3 is formed in a substantially circular shape in a plan view and is supported by a support member 31. A substantially circular recess 32 is formed in the surface of the stage 3 for placing the substrate W, for example, with a diameter of 300 mm. The recess 32 has an inner diameter slightly larger than the diameter of the substrate W. The depth of the recess 32 is configured to be substantially the same as the thickness of the substrate W, for example. The stage 3 is made of a ceramic material such as aluminum nitride (AlN). Alternatively, the stage 3 may be made of a metal material such as nickel (Ni). Instead of the recess 32, a guide ring that guides the substrate W may be provided around the periphery of the surface of the stage 3.

[0078] A grounded lower electrode 33 is embedded in the stage 3, for example. A heating mechanism 34 is embedded below the lower electrode 33. The heating mechanism 34 receives power from a power supply (not shown) based on a control signal from the control unit 100, thereby heating the substrate W placed on the stage 3 to a set temperature. If the entire stage 3 is made of metal, the entire stage 3 functions as the lower electrode, and the lower electrode 33 does not need to be embedded in the stage 3. The stage 3 is provided with a plurality of (e.g., three) lift pins 41 for holding and elevating the substrate W placed on the stage 3. The lift pins 41 may be made of, for example, ceramics such as alumina (Al2O3), quartz, or the like. The lower ends of the lift pins 41 are attached to a support plate 42. The support plate 42 is connected to a lift mechanism 44 provided outside the processing chamber 2 via a lift shaft 43.

[0079] The lifting mechanism 44 is installed, for example, below the exhaust chamber 21. The bellows 45 is provided between the lifting mechanism 44 and an opening 211 for the lifting shaft 43 formed in the lower surface of the exhaust chamber 21. The support plate 42 may be shaped so that it can be raised and lowered without interfering with the support member 31 of the stage 3. The lifting pins 41 are configured to be able to be raised and lowered by the lifting mechanism 44 between above and below the surface of the stage 3.

[0080] A gas supply unit 5 is provided on the ceiling wall 27 of the processing chamber 2 via an insulating member 28. The gas supply unit 5 serves as an upper electrode and faces the lower electrode 33. A high-frequency power supply 512 is connected to the gas supply unit 5 via a matching unit 511. By supplying high-frequency power of 100 kHz to 2.45 GHz, preferably 450 kHz to 100 MHz, from the high-frequency power supply 512 to the upper electrode (gas supply unit 5), a high-frequency electric field is generated between the upper electrode (gas supply unit 5) and the lower electrode 33, and capacitively coupled plasma is generated. The plasma generation unit 51 includes the matching unit 511 and the high-frequency power supply 512. Note that the plasma generation unit 51 is not limited to capacitively coupled plasma, and may be one that generates other types of plasma, such as inductively coupled plasma. Furthermore, plasmatized gas may be supplied from a remote plasma source.

[0081] The gas supply unit 5 includes a hollow gas supply chamber 52. A number of holes 53 are arranged, for example, evenly, on the bottom surface of the gas supply chamber 52 for dispersively supplying the processing gas into the processing vessel 2. A heating mechanism 54 is embedded in the gas supply unit 5, for example, above the gas supply chamber 52. The heating mechanism 54 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 100.

[0082] A gas supply passage 6 is provided in the gas supply chamber 52. The gas supply passage 6 is connected to the gas supply chamber 52. Gas sources G61, G62, and G63 are connected upstream of the gas supply passage 6 via gas lines L61, L62, and L63, respectively. The number of gas sources and the types of gas are not limited to those shown in the figure.

[0083] The gas source G61 is a TiCl4 gas source and is connected to the gas supply path 6 via a gas line L61. A mass flow controller M61, a storage tank T61, and a valve V61 are provided on the gas line L61 in this order from the gas source G61 side. The mass flow controller M61 controls the flow rate of the TiCl4 gas flowing through the gas line L61. With the valve V61 closed, the storage tank T61 stores the TiCl4 gas supplied from the gas source G61 via the gas line L61, thereby increasing the pressure of the TiCl4 gas in the storage tank T61. The valve V61 opens and closes to supply and cut off the TiCl4 gas to the gas supply path 6.

[0084] The gas source G62 is an Ar gas source and is connected to the gas supply path 6 via a gas line L62. A mass flow controller M62 and a valve V62 are provided on the gas line L62, in this order from the gas source G62 side. The mass flow controller M62 controls the flow rate of Ar gas flowing through the gas line L62. The valve V62 opens and closes to supply and cut off Ar gas to the gas supply path 6.

[0085] The gas source G63 is an O2 gas source and is connected to the gas supply path 6 via a gas line L63. A mass flow controller M63 and a valve V63 are provided on the gas line L63 in this order from the gas source G63 side. The mass flow controller M63 controls the flow rate of O2 gas flowing through the gas line L63. The valve V63 opens and closes to supply and cut off the O2 gas to the gas supply path 6.

[0086] The film forming apparatus 1 includes a control unit 100 and a storage unit 101. The control unit 100 includes a CPU, RAM, ROM, etc. (none of which are shown), and performs overall control of the film forming apparatus 1 by, for example, having the CPU execute a computer program stored in the ROM or storage unit 101. Specifically, the control unit 100 performs a film forming process on the substrate W by having the CPU execute a control program stored in the storage unit 101 and controlling the operation of each component of the film forming apparatus 1.

[0087] Next, the operation of the film forming apparatus 1 will be described with reference to FIG. 11 again. First, the control unit 100 opens the gate valve 26 and causes the transfer mechanism to transfer the substrate W into the processing chamber 2 and place it on the stage 3. The substrate W is placed horizontally with its front surface Wa facing up. The control unit 100 then retracts the transfer mechanism from the processing chamber 2 and closes the gate valve 26. Next, the control unit 100 heats the substrate W to a set temperature using the heating mechanism 34 of the stage 3 and adjusts the pressure inside the processing chamber 2 to a set pressure using the pressure adjustment unit 23. For example, step S101 in FIG. 1 includes steps such as loading the substrate W into the processing chamber 2.

[0088] Next, the control unit 100 performs step S102 of Fig. 1. In step S102, the valves V61, V62, and V63 are opened to simultaneously supply TiCl4 gas, Ar gas, and O2 gas into the processing chamber 2.

[0089] Specific processing conditions in step S102 are as follows, for example: TiCl4 gas flow rate: 1sccm to 500sccm Ar gas flow rate: 100sccm to 100,000sccm O2 gas flow rate: 100sccm to 100,000sccm Processing time: 0.1 seconds to 30 seconds Processing temperature: 100℃~450℃ Processing pressure: 3Pa~10000Pa.

[0090] Next, the control unit 100 performs step S103 in Fig. 1. In step S103, the valve V61 is closed. At this time, since the valves V62 and V63 are open, Ar gas and O2 gas are supplied into the processing vessel 2, and TiCl4 gas remaining in the processing vessel 2 is exhausted to the exhaust pipe 22.

[0091] Specific processing conditions in step S103 are as follows, for example: Ar gas flow rate: 100sccm to 100,000sccm O2 gas flow rate: 100sccm to 100,000sccm Processing time: 0.1 seconds to 30 seconds Processing temperature: 100℃~450℃ Processing pressure: 3Pa~10000Pa.

[0092] Next, the control unit 100 performs step S104 of FIG. 1. In step S104, plasma is generated by the plasma generation unit 51, and O2 gas is converted into plasma. As a result, the adsorbed TiCl4 gas is oxidized, and a TiO film, for example, is formed. The TiO film is selectively formed on the second film W2 relative to the first film W1. The specific processing conditions for step S104 are the same as the processing conditions for step S103 above, except for the generation of plasma, and therefore will not be described again.

[0093] Next, the control unit 100 performs step S105 of FIG. 1. In step S105, plasma generation is stopped. At this time, since valves V62 and V63 are open, Ar gas and O2 gas are supplied into the processing vessel 2, and plasma-converted gas remaining in the processing vessel 2 is exhausted to the exhaust pipe 22. The specific processing conditions for step S105 are the same as those for step S103, and therefore will not be described here.

[0094] 1, the control unit 100 checks whether steps S102 to S105 have been performed N times (N is a natural number equal to or greater than 1). If the number of times is less than N (step S106, NO), the control unit 100 performs steps S102 to S105 again. On the other hand, if the number of times has reached N (step S106, YES), the control unit 100 ends this process. Thereafter, the control unit 100 opens the gate valve 26 and transports the substrate W out of the processing vessel 2 by the transport mechanism. The control unit 100 retracts the transport mechanism from the processing vessel 2, and then closes the gate valve 26.

[0095] Note that control unit 100 may perform steps S201 to S205 shown in Fig. 9. Control unit 100 may also perform a series of processes shown in Fig. 20. The series of processes includes performing steps S201 to S204 M (M is an integer greater than or equal to 1) times and performing steps S102 to S105 N (N is an integer greater than or equal to 1) times. Control unit 100 performs the series of processes K (K is an integer greater than or equal to 1) times.

[0096] 1, steps S102 to S105 are performed N times, but steps S102A and S103A may be performed after step S103 and before step S104, as shown in Table 12 described later. Step S102A is performed in the same manner as step S102, except that a source gas different from that used in step S102 is used. Step S103A is performed in the same manner as step S103.

[0097] As shown in Table 12 below, a source gas containing element X1 as element X, a source gas containing element X2 different from element X1 as element X, and a plasma-activated reactive gas are repeatedly supplied to selectively form a third film W3, which is an oxide film of element X (specifically, elements X1 and X2), on the second film W2 relative to the first film W1. One of element X1 and element X2 is a metal element (preferably a transition metal element), and the other is a semiconductor element. By performing both steps S102 and S102A, crystallization of the third film W3 can be suppressed, and the flatness of the third film W3 can be improved.

[0098] In Table 12, element X1 is a metal element and element X2 is a semiconductor element, but element X1 may be a semiconductor element and element X2 may be a metal element. Furthermore, the combination of element X1 and element X2 may be a combination of two metal elements or two semiconductor elements. Element X may contain element X3, which is different from elements X1 and X2, or may contain three or more elements that are different from each other. The control unit 100 may also supply a source gas containing element X3.

[0099] Furthermore, as shown in Table 13 below, steps S102A to S105A may be performed after the nth (n is any natural number between 1 and N) steps S102 to S105 and before the (n+1)th steps S102 to S105. Step S102A is performed in the same manner as step S102, except that a source gas different from that used in step S102 is used. Steps S103A to S105A are performed in the same manner as steps S103 to S105.

[0100] As shown in Table 13 below, a third film W3, which is an oxide film of element X (specifically, elements X1 and X2), may be selectively formed on the second film W2 relative to the first film W1 by repeatedly supplying a source gas containing element X1 as element X, a plasmatized reactive gas, a source gas containing element X2 different from element X1 as element X, and a plasmatized reactive gas. One of element X1 and element X2 is a metal element (preferably a transition metal element), and the other is a semiconductor element. By performing both steps S102 and S102A, crystallization of the third film W3 can be suppressed, and the flatness of the third film W3 can be improved.

[0101] In Table 13, element X1 is a metal element and element X2 is a semiconductor element, but element X1 may be a semiconductor element and element X2 may be a metal element. Furthermore, the combination of element X1 and element X2 may be a combination of two metal elements or two semiconductor elements. Element X may contain element X3, which is different from elements X1 and X2, or may contain three or more elements that are different from each other. The control unit 100 may also supply a source gas containing element X3.

[0102] [Example] Next, examples will be described. The following Examples 1, 5, and 9 to 17 are examples, and the following Examples 2 to 4 and 6 to 8 are comparative examples.

[0103] [Example 1] In Example 1, a substrate having the surface of a B film W1-1 and the surface of an SiO film W2-1 on the same plane as shown in FIG. 12 was prepared, and steps S102 to S105 in FIG.

[0104] [Table 1]

[0105] In Table 1, "RF" "ON" means that the gas was converted into plasma by high-frequency power. "RF" "OFF" means that the gas was not converted into plasma. The same applies to Tables 2, 3, 5, 7, 8, and 10 to 16 below.

[0106] As shown in Table 1, in Example 1, TiCl gas and plasma-converted O gas were alternately supplied to the substrate surface by the plasma ALD method. As a result, a TiO film W3-1 was selectively formed on the SiO film W2-1 relative to the B film W1-1, as shown in Figure 13.

[0107] [Example 2 to Example 4] In Examples 2 to 4, a substrate having the same structure as that shown in FIG. 12 was prepared, and a TiO film was formed by thermal ALD, thermal CVD, or plasma CVD, but in all cases, the TiO film was formed over the entire surface of the substrate.

[0108] In Example 2, a substrate heated to 350° C. was subjected to alternate supply of TiCl 4 gas and supply of non-plasma H 2 O gas 300 times by thermal ALD.

[0109] In Example 3, TiCl4 gas and non-plasma O3 gas were simultaneously supplied to a substrate heated to 350°C by thermal CVD.

[0110] In Example 4, TiCl4 gas and plasma-converted O2 gas were simultaneously supplied to a substrate heated to 350°C by plasma CVD.

[0111] Comparing Example 1 with Examples 2 to 4, it is clear that it is important to use the plasma ALD method in order to selectively form a TiO film on an SiO film relative to a B film.

[0112] [Example 5] In Example 5, a substrate having the surface of a BN film W1-5 and the surface of an SiO film W2-5 on the same plane as shown in FIG. 33 was prepared, and the treatment of FIG.

[0113] [Table 2]

[0114] As shown in Table 2, in Example 5, TiCl4 gas and non-plasma O3 gas were alternately supplied 300 times by thermal ALD to the substrate surface heated to 400°C. As a result, a TiO film W3-5 was selectively formed on the SiO film W2-5 relative to the BN film W1-5, as shown in Figure 34.

[0115] [Examples 6 to 8] In Example 6, a substrate with the same structure as that shown in Figure 12 was prepared, and a Ti film was formed by plasma ALD, but the Ti film was formed over the entire surface of the substrate. In the plasma ALD method of Example 6, TiCl4 gas and plasma H2 gas were alternately supplied to the substrate heated to 350°C.

[0116] In Example 7, a substrate with the same structure as that shown in Figure 12 was prepared, and a TiN film was formed by plasma ALD, but the TiN film was formed over the entire surface of the substrate. In the plasma ALD method of Example 7, TiCl4 gas and plasma NH3 gas were alternately supplied to the substrate heated to 350°C.

[0117] In Example 8, a substrate with the same structure as that shown in Figure 12 was prepared, and a TiN film was formed by thermal ALD, but the TiN film ended up being formed over the entire surface of the substrate. In the plasma ALD method of Example 8, TDMAT (Ti[N(CH3)2]4) gas and non-plasma NH3 gas were alternately supplied to the substrate heated to 250°C.

[0118] Comparing Example 1 with Examples 6 to 8, it is clear that in order to selectively form a Ti-containing film on an SiO film relative to a B film, it is important to convert an oxygen-containing reactive gas into plasma, and to form an oxide film.

[0119] [Example 9] In Example 9, a substrate was prepared in which a recess was formed in part of the surface of the B film W1-9 as shown in FIG. 14, and the SiO film W2-9 was exposed only on the bottom surface of the recess, and steps S102 to S105 in FIG. 1 were performed under the processing conditions shown in Table 3.

[0120] [Table 3]

[0121] As shown in Table 3, in Example 9, TiCl gas and plasma-converted O gas were alternately supplied to the substrate surface. As a result, the TiO film W3-9 was selectively filled inside the recesses of the B film W1-9, as shown in Figure 15.

[0122] [Example 10] In Example 10, steps S102 to S105 in FIG. 1 were performed on the various base films shown in Table 4 under the processing conditions shown in Table 5. Thereafter, the thickness of the TiO film formed on the various base films was measured. The thickness measurement results are shown in Table 4. In Table 4, "c-Si" stands for crystalline silicon.

[0123] [Table 4]

[0124] [Table 5]

[0125] As is clear from Table 4, a TiO film was not formed on the film containing B, whereas a TiO film was formed on the film containing substantially no B. A similar tendency was observed under processing conditions where N in step S106 exceeded 1000.

[0126] [Example 11] In Example 11, steps S201 to S205 in FIG. 9 were performed on the various base films shown in Table 6 under the processing conditions shown in Table 7, and then steps S102 to S106 in FIG. 1 were performed under the processing conditions shown in Table 8. Thereafter, the thicknesses of the third films (TiO films) formed on the various base films were measured. The thickness measurement results are shown in Table 6.

[0127] [Table 6]

[0128] [Table 7]

[0129] [Table 8]

[0130] As is clear from Table 6, a third film (TiO film) was not formed on the TiO2 film and Ru film, but a third film (TiO film) was formed on the SiO2 film and Mo film. Comparing Table 4 and Table 6, it is estimated that a BN film was formed on the TiO2 film and Ru film, but not on the SiO2 film and Mo film. A similar tendency was observed under processing conditions where N in step S106 exceeded 1000.

[0131] [Example 12] In Example 12, steps S201 to S205 in FIG. 9 were performed on the various base films shown in Table 9 under the processing conditions shown in Table 10, and then steps S102 to S106 in FIG. 1 were performed under the processing conditions shown in Table 11. Thereafter, the thicknesses of the third films (TiO films) formed on the various base films were measured. The thickness measurement results are shown in Table 9.

[0132] [Table 9]

[0133] [Table 10]

[0134] [Table 11]

[0135] As is clear from Table 9, a third film (TiO film) was not formed on the SiO film, but a third film (TiO film) was formed on the TiO film, Mo film, and Ru film. Comparing Tables 4 and 9, it is estimated that a BN film was formed on the SiO film, but not on the TiO film, Mo film, and Ru film. A similar trend was observed even under processing conditions where N in step S106 exceeded 1,000. The difference in the film type of the base film on which the BN film was formed between Example 11 and Example 12 is estimated to be mainly due to the difference in the type of gas used to generate plasma in step S203. In step S203 of Example 11, NH gas was used as shown in Table 7, whereas in step S203 of Example 12, a mixture of N gas and H gas was used as shown in Table 10.

[0136] [Example 13] In Example 13, a substrate having the surface of the B film W1-13 and the surface of the SiO film W2-13 on the same plane was prepared as shown in Fig. 16, and steps S102 to S105 in Fig. 1 were performed under the processing conditions shown in Table 12. In Example 13, as shown in Table 12, steps S102A and S103A were performed after step S103 and before step S104.

[0137] [Table 12]

[0138] As shown in Table 12, in Example 13, TiCl4 gas, SiCl4 gas, and plasma-converted O2 gas were supplied to the substrate surface in this order by the plasma ALD method, and this was repeated N (N = 300) times. As a result, a TiSiO film W3-13 was selectively formed on the SiO film W2-13 relative to the B film W1-13, as shown in Figure 17.

[0139] [Example 14] In Example 14, as shown in Fig. 18, a substrate having the surface of the B film W1-14 and the surface of the SiO film W2-14 on the same plane was prepared, and steps S102 to S105 in Fig. 1 were performed under the processing conditions shown in Table 13. Note that in Example 14, as shown in Table 13, steps S102A to S105A were performed after the nth (n is any natural number between 1 and N) step S102 to S105 and before the n+1th step S102 to S105.

[0140] [Table 13]

[0141] As shown in Table 13, in Example 14, TiCl4 gas, plasma-converted O2 gas, SiCl4 gas, and plasma-converted O2 gas were supplied to the substrate surface in this order by the plasma ALD method, and this process was repeated N (N=300) times. As a result, a TiSiO film W3-14 was selectively formed on the SiO film W2-14 relative to the B film W1-14, as shown in Figure 19.

[0142] [Example 15] In Example 15, a substrate having the surface of a B film W1-15 and the surface of an SiO film W2-15 on the same plane as shown in FIG. 26 was prepared, and steps S102 to S105 in FIG.

[0143] [Table 14]

[0144] As shown in Table 14, in Example 15, Si2Cl6 gas and plasma-converted O2 gas were alternately supplied to the substrate surface by plasma ALD. As a result, an SiO film W3-15 was selectively formed on the SiO film W2-15 relative to the B film W1-15, as shown in Figure 27.

[0145] [Example 16] In Example 16, a substrate having the surface of a Ru film W4-16 and the surface of a SiO film W2-16 on the same plane as shown in FIG. 28 was prepared, and steps S201, S203, S204, and S102 to S105 in FIG. 20 were performed under the processing conditions shown in Table 15.

[0146] [Table 15]

[0147] As a result, in Example 16, a TiO film W3-16 was selectively formed on the SiO film W2-16 relative to the Ru film W4-16, as shown in Figure 29. This is presumably because a BN film was formed on the Ru film W4-16, but not on the SiO film W2-16. The results of Example 16 are consistent with those of Example 11 (see Table 6).

[0148] [Example 17] In Example 17, a substrate having the surface of a Ru film W4-17 and the surface of a SiO film W2-17 on the same plane as shown in FIG. 30 was prepared, and steps S201 to S204 and S102 to S105 in FIG. 20 were performed under the processing conditions shown in Table 16.

[0149] [Table 16]

[0150] As a result, in Example 17, a TiO film W3-17 was selectively formed on the SiO film W2-17 relative to the Ru film W4-17, as shown in Figure 31. This is presumably because a B film was formed on the Ru film W4-17, but not on the SiO film W2-17.

[0151] 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]

[0152] W substrate W1 First Membrane W2 2nd film W3 Third Membrane

Claims

1. preparing a substrate having a first film containing boron and a second film formed on a surface thereof, the second film being made of a material different from that of the first film; supplying a source gas containing a halogen and an element X other than a halogen to the surface of the substrate; supplying a reactive gas containing oxygen in plasma form to the surface of the substrate; Including, and selectively forming a third film, which is an oxide film of the element X, on the second film relative to the first film by alternately supplying the source gas and the plasmatized reactive gas.

2. preparing a substrate having a first film containing boron and a second film formed on a surface thereof, the second film being made of a material different from that of the first film; supplying a source gas containing a halogen and an element X other than a halogen to the surface of the substrate; O ３ Supplying the gas without converting it into plasma; Including, The supply of the raw material gas and the O ３ and alternately supplying a gas containing the element X and a second gas, thereby selectively forming a third film, which is an oxide film of the element X, on the second film with respect to the first film.

3. 3. The film forming method according to claim 1, wherein the second film contains substantially no boron.

4. 3. The film forming method according to claim 1, wherein preparing the substrate includes selectively forming the first film on a fourth film formed of a material different from that of the second film.

5. preparing the substrate having the second film and the fourth film on a surface thereof; selectively forming the first film on the fourth film relative to the second film; selectively forming the third film on the second film relative to the first film; selectively forming the first film again on the fourth film or the first film relative to the third film; forming the third film again on the third film selectively relative to the first film; The film forming method according to claim 4 , comprising the steps of:

6. 3. The film forming method according to claim 1, wherein the substrate has a recess on the surface, the first film is exposed only inside the recess, and the first film is exposed at least on the bottom surface of the recess.

7. 3. The film forming method according to claim 1, wherein the substrate has a recess on the surface, the second film is exposed only inside the recess, and the second film is exposed at least on the bottom surface of the recess.

8. The film forming method according to claim 1 , wherein the element X includes a metal element.

9. The film forming method according to claim 1 , wherein the element X includes a transition metal element.

10. The film forming method according to claim 1 , wherein the element X includes a semiconductor element.

11. 2. The film forming method according to claim 1, further comprising: selectively forming the third film, which is an oxide film of the element X, on the second film relative to the first film by repeatedly supplying the source gas containing the element X1 as the element X, supplying the source gas containing the element X2 different from the element X1 as the element X, and supplying the plasmatized reactive gas.

12. 2. The film forming method according to claim 1, further comprising: selectively forming the third film, which is an oxide film of the element X, on the second film relative to the first film by repeatedly supplying the source gas containing the element X1 as the element X, supplying the plasmatized reactive gas, supplying the source gas containing the element X2 different from the element X1 as the element X, and supplying the plasmatized reactive gas.

13. supplying the source gas containing an element X1 as the element X; supplying the source gas containing an element X2 different from the element X1 as the element X; ３ 3. The film forming method according to claim 2, further comprising: selectively forming the third film, which is an oxide film of the element X, on the second film with respect to the first film by repeatedly supplying a gas containing the element X.

14. supplying the source gas containing element X1 as the element X; ３ supplying a source gas containing an element X2 different from the element X1 as the element X; ３ 3. The film forming method according to claim 2, further comprising: selectively forming the third film, which is an oxide film of the element X, on the second film with respect to the first film by repeatedly supplying a gas containing the element X.

15. 15. The film forming method according to claim 11, wherein one of the element X1 and the element X2 is a metal element and the remaining one is a semiconductor element.

16. The film forming method according to claim 1 , wherein the element X includes three or more elements different from one another.

17. 2. The film forming method according to claim 1, wherein the supply of the source gas and the supply of the plasmatized reactive gas are alternately carried out at a temperature of 100° C. to 800° C.

18. The supply of the raw material gas and the O ３ 3. The film forming method according to claim 2, wherein the supply of the gas is alternately performed at a temperature of 100° C. to 800° C.

19. a processing vessel that accommodates a substrate having a first film containing boron and a second film formed on a surface thereof, the second film being made of a material different from that of the first film; a holder that holds the substrate inside the processing vessel; a supply unit that supplies a gas to the surface of the substrate held by the holder; a plasma generating unit that generates plasma from the gas; a control unit that controls the supply unit and the plasma generation unit; Equipped with the control unit controls a source gas containing a halogen and an element X other than a halogen, and a reactive gas containing oxygen in plasma, to selectively form a third film, which is an oxide film of the element X, on the second film with respect to the first film.

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