Film deposition method and film deposition apparatus

Abstract

We provide technology that improves the selectivity of selective film formation. [Solution] The film formation method comprises supplying a modifying gas to the substrate to modify the third film, thereby making the film formation inhibitory effect of the second part of the third film on the fourth film more pronounced than that of the first part of the third film, and selectively forming the fourth film on the first part of the third film modified with the modifying gas. Forming the fourth film includes forming the fourth film containing element X by alternately or simultaneously supplying to the substrate a raw material gas containing halogen and element X other than halogen, and a reaction gas that reacts with adsorbents of the raw material gas.

Description

Technical Field

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

Background Art

[0002] The film forming method described in Patent Document 1 includes the following (A) to (C). (A) Prepare a substrate having a first film containing boron and a second film formed of a material different from the first film on the surface. (B) Supply a source gas containing a halogen and an element X other than the halogen to the surface of the substrate. (C) Supply a reaction gas containing oxygen in a plasma state to the surface of the substrate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] One embodiment of the present disclosure provides a technique for improving the selectivity of selective film formation.

Means for Solving the Problems

[0005] A film-forming method according to one embodiment of the present disclosure comprises preparing a substrate having a first film and a second film formed of a different material from the first film in different regions of its surface, and forming a third film containing boron on both the first and second films. The third film has a first portion formed on the first film and a second portion formed on the second film. The film-forming method comprises supplying a modifying gas to the substrate to modify the third film, thereby making the film-forming inhibitory effect of the second portion on the fourth film more pronounced than that of the first portion of the third film, and selectively forming the fourth film on the first portion of the third film modified with the modifying gas. Forming the fourth film includes forming the fourth film containing element X by alternately or simultaneously supplying to the substrate a source gas containing a halogen and an element X other than a halogen, and a reaction gas that reacts with adsorbents of the source gas. [Effects of the Invention]

[0006] According to one embodiment of the present disclosure, the selectivity of selective film formation can be improved. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a flowchart showing a film deposition method according to one embodiment. [Figure 2] Figure 2 is a flowchart showing an example of S102 as shown in Figure 1. [Figure 3] Figure 3 is a flowchart showing an example of S104 as shown in Figure 1. [Figure 4] Figure 4 is a cross-sectional view showing a film deposition method according to one embodiment. [Figure 5] Figure 5 is a cross-sectional view showing an example of a structural difference in the third layer resulting from the material difference between the first and second layers. [Figure 6] Figure 6 is a cross-sectional view showing a film deposition apparatus according to one embodiment. [Figure 7] Figure 7 is a cross-sectional view showing an example of the first processing unit. [Figure 8]Figure 8 is a TEM photograph of the substrate after processing under the conditions of Example 1 shown in Table 1. [Figure 9] Figure 9 is a TEM photograph of the substrate after processing under the conditions of Example 2 shown in Table 1. [Figure 10] Figure 10 is a TEM image of the substrate after processing under the conditions of Example 3 shown in Table 1. [Modes for carrying out the invention]

[0008] Embodiments of this disclosure will be described below with reference to the drawings. In each drawing, the same or corresponding components are denoted by the same reference numerals, and their descriptions may be omitted.

[0009] First, a film deposition method according to one embodiment will be described, mainly with reference to Figure 1. The film deposition method includes, for example, steps S101 to S105 shown in Figure 1. Note that the film deposition method only needs to include at least steps S101 to S104. Furthermore, the film deposition method may include steps other than steps S101 to S105 shown in Figure 1.

[0010] Step S101 includes preparing a substrate W as shown in Figure 4. The substrate W has a first film W1 and a second film W2 formed of a different material from the first film W1 in different regions of its surface Wa. Hereinafter, the surface Wa of the substrate W may be referred to as the substrate surface Wa. The first film W1 and the second film W2 are formed on, for example, an unshown base substrate. The base 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 combination of the first film W1 and the second film W2 is not particularly limited, as long as the film formation inhibitory effect of the second part W3-2 of the third film W3 on the fourth film W4 can be made apparent in step S103 compared to the first part W3-1 of the third film W3. For example, the first film W1 may be a Si-containing film and the second film W2 may be a metal-containing film. Alternatively, the first film W1 may be a metal-containing film and the second film W2 may be a Si-containing film. Whether the film formation inhibitory effect of the third film W3 on the metal-containing film or the third film W3 on the Si-containing film is made apparent can be adjusted by the type of reformed gas, as will be described later. Neither the first film W1 nor the second film W2 needs to substantially contain boron (B). Substantially containing no B means that the B content is 0 atomic% to 5 atomic%. A lower B content is preferable.

[0012] The Si-containing film is not particularly limited, but examples include Si films, SiGe films, SiO films, SiN films, SiOC films, SiON films, or SiOCN films. Here, an SiO film means a film containing silicon (Si) and oxygen (O). The atomic ratio of Si to O in an SiO film is usually 1:2, but is not limited to 1:2. Similarly, SiGe films, SiN films, SiOC films, SiON films, and SiOCN films also mean that they contain each element, and are not limited to stoichiometric ratios. The Si-containing film may also be an interlayer insulating film. The interlayer insulating film is preferably a low-dielectric constant (Low-k) film. Si films and SiGe films are semiconductor films. The semiconductor film may be a single-crystal film, a polycrystalline film, or an amorphous film.

[0013] The metal-containing film is not particularly limited, but is, for example, a metal film. Examples of metal films include Cu films, Co films, Ru films, Mo films, W films, Al films, or Ti films. The metal film may also be an alloy film. The metal-containing film may also be a metal nitride film. Examples of metal nitride films are not particularly limited, but are, for example, TiN films or TaN films. Here, a 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 stoichiometric ratios.

[0014] Step S102 includes forming a third film W3 on both the first film W1 and the second film W2 as shown in FIG. 4. The third film W3 has a first portion W3-1 formed on the first film W1 and a second portion W3-2 formed on the second film W2. The first portion W3-1 and the second portion W3-2 have basically the same structure and a film thickness such that the surfaces of the first film W1 and the second film W2 are not both exposed. Here, the structure includes the composition. However, the first portion W3-1 and the second portion W3-2 have a structural difference resulting from the material difference between the first film W1 and the second film W2 as shown in FIG. 5. The content of FIG. 5 will be described later.

[0015] The third film W3 contains boron (B) in both the first portion W3-1 and the second portion W3-2. The B content in the third film W3 is, for example, 20 atomic % to 100 atomic %, preferably 40 atomic % to 100 atomic %. The third film W3 is, for example, a B film, a BN film, a BNC film, a BO film, a BNO film, a BNOC film, a SiBN film, a SiBCN film or a SiOBN film. Here, the BN film means a film containing boron (B) and nitrogen (N). The atomic ratio of B and N in the BN film is not limited to 1:1. The same applies to BNC films and the like other than the BN film, meaning that each element is included and is not limited to the stoichiometric ratio.

[0016] Step S102 has, for example, steps S102a to S102e as shown in FIG. 2. Note that step S102 only needs to have steps S102a and S102c and does not necessarily have steps S102b, S102d and S102e. Hereinafter, steps S102a to S102e will be described.

[0017] Step S102a includes supplying a second source gas to the substrate W. The second source gas contains boron. The second source gas includes, for example, tris(dimethylamino)borane (TDMAB: C6H

[0016] , , , 18 ,

[0018] , , , , ,

[0017] BN3). The second source gas may be supplied together with a dilution gas. The dilution gas is, for example, an Ar gas or a N2 gas. <00,00098> Furthermore, the second raw material gas is not limited to those containing TDMABs, but may include, for example, diborane (B2H6), boron trichloride (BCl3), boron trifluoride (BF3), and trisethylmethylaminoborane (C9H6). 24 BN3), trimethylborane (C3H9B), or triethylborane (C6H 15 B) It may also contain cyclotriborazane (B3N3H6), etc.

[0019] Step S102b includes supplying a purge gas to the substrate W. The purge gas purges any excess second raw material gas that was not adsorbed on the substrate surface Wa in step S102a. As the purge gas, for example, a noble gas such as Ar gas or N2 gas can be used.

[0020] Step S102c includes supplying a second reaction gas to the substrate W. The second reaction gas reacts with adsorbents of the second raw material gas on the substrate surface Wa to form a third film W3. The second reaction gas includes, for example, at least one of a nitrogen-containing gas, an oxygen-containing gas, and a reducing gas. The nitrogen-containing gas nitrides the second raw material gas to form a boron nitride film. The nitrogen-containing gas includes, for example, NH3, N2, N2H4, or N2H2. The oxygen-containing gas oxidizes the second raw material gas to form a boron oxide film. The oxygen-containing gas includes, for example, O2, O3, H2O, NO, or N2O. The reducing gas reduces the second raw material gas to form a boron film. The reducing gas includes, for example, H2, SiH4, or H2S gas. The second reaction gas may be supplied together with a diluent gas such as Ar gas.

[0021] Step S102c may include plasmaizing the second reaction gas, and may also include supplying the plasmaized second reaction gas to the substrate surface Wa. Plasmaizing the second reaction gas can promote the formation of the third film W3.

[0022] The second reaction gas may be supplied not only in step S102c, but also in all of steps S102a to S102d. However, the plasma generation of the second reaction gas is performed only in step S102c. This is because plasma generation of the second reaction gas promotes the reaction of the adsorbed second raw material gas on the substrate surface Wa.

[0023] Step S102d includes supplying a purge gas to the substrate W. The purge gas purges any excess second reaction gas that did not react with the substrate surface Wa in step S102c. As the purge gas, for example, a noble gas such as Ar gas or N2 gas can be used.

[0024] In step S102e, it is confirmed whether steps S102a to S102d above have been performed K times (where K is an integer greater than or equal to 1). K may be an integer greater than or equal to 2, and steps S102a to S102d above may be repeated. The thickness of the third film W3 can be increased.

[0025] If the number of times steps S102a to S102d are performed is less than K (step S102e, NO), the thickness of the third film W3 is less than the target value, so steps S102a to S102d are performed again. The third film W3 inhibits the formation of the fourth film W4 in step S104, and it is desirable that it be formed thick enough so that the second film W2 is not exposed. Unlike the third film W3, the second film W2 does not substantially contain B.

[0026] The third membrane W3 is thought to form when nuclei grow on the surface of the second membrane W2 and adjacent nuclei come into contact with each other. Until the nuclei reach a sufficient size, it is thought that the exposed portions of the second membrane W2 are dispersed. Therefore, the thickness of the third membrane W3 is preferably 10 Å or more. If the thickness of the third membrane W3 is less than 10 Å, it is thought that portions of the second membrane W2 remain exposed, and the effect of inhibiting the formation of the fourth membrane W4 is weakened.

[0027] On the other hand, if the number of times steps S102a to S102d are performed reaches K (step S102e, YES), the thickness of the third film W3 has reached the target value, and step S102 is terminated.

[0028] The method for forming the third film W3 shown in Figure 2 is the ALD method, but the CVD method may also be used. In the ALD method, the supply of the second raw material gas and the supply of the second reaction gas are performed alternately. On the other hand, in the CVD method, the supply of the second raw material gas and the supply of the second reaction gas are performed simultaneously.

[0029] The third film W3 may also be a molecular film formed by chemical or physical adsorption of molecules. The molecules are supplied to the substrate surface in gaseous form. The gas has functional groups in its molecules that readily adsorb to the substrate surface and also contains boron (B). The third film W3 may also be formed when the adsorbed molecules decompose due to the heat of the substrate W.

[0030] Step S103 includes supplying a modifying gas to the substrate W to modify the third film W3, thereby making the film formation inhibitory properties of the second part W3-2 of the third film W3 compared to the first part W3-1 of the third film W3 toward the fourth film W4. If step S103 were omitted and step S104 was performed after step S102, the fourth film W4 could be formed not only on the first part W3-1 of the third film W3 but also on the second part W3-2. According to this embodiment, because step S103 is included, the fourth film W4 can be selectively formed on the first part W3-1 of the third film W3 relative to the second part W3-2 in step S104. Therefore, the selectivity of selective film formation can be improved.

[0031] Referring to Figure 5, an example of the structural difference of the third film W3 resulting from the material difference between the first film W1 and the second film W2 will be explained. In Figure 5, material A represents the material of the metal-containing film, and material B represents the material of the Si-containing film. Material A may contain oxygen resulting from the oxidation of the metal. Material A can be either the material of the first film W1 or the second film W2 shown in Figure 4. Similarly, material B can be either the material of the first film W1 or the second film W2 shown in Figure 4.

[0032] In Figure 5, W3A is part of the third film W3, and W3B is another part of the third film W3. W3A is formed on material A, and W3B is formed on material B. W3A can be either part 1 W3-1 or part 2 W3-2 shown in Figure 4. Similarly, W3B can be either part 1 W3-1 or part 2 W3-2 shown in Figure 4.

[0033] In Figure 5, "○" represents oxidized sites, and "×" represents sites that adsorb the source gas for the fourth film W4. For example, "×" could be impurities containing hydrogen (H) or halogens, defect sites, or unbonded sites. Before step S103, W3A has a higher density of the sites indicated by "○" in Figure 5 compared to W3B. This is because the metals contained in material A release oxygen more easily than the silicon (Si) contained in material B. When the sites indicated by "○" are dense and regularly arranged, they do not readily adsorb the source gas for the fourth film W4, but when the density is low and the arrangement is irregular, they readily adsorb the source gas for the fourth film W4, similar to the sites indicated by "×". The density of the sites indicated by "×" in Figure 5 is about the same for both W3A and W3B. Therefore, before step S103, the fourth film W4 is likely to form on both W3A and W3B.

[0034] In step S103, when an oxidizing gas is supplied to the third film W3 as a reforming gas, oxidation of the third film W3 progresses. Compared to W3B, W3A has a higher density of the regions indicated by "○" in Figure 5 before step S103, and in step S103, the density of the regions indicated by "○" increases and rearrangement progresses more easily. Therefore, W3A is more likely to exhibit film formation inhibition than W3B.

[0035] Oxidizing gases are not specifically defined, but examples include plasma-treated O2 gas, non-plasma-treated O3 gas, non-plasma-treated H2O gas, plasma-treated N2O gas, plasma-treated NO2 gas, or non-plasma-treated O2 gas.

[0036] On the other hand, when a non-oxidizing gas is supplied to the third membrane W3 as a reforming gas in step S103, removal proceeds for both the sites indicated by "○" and "×" in Figure 5. W3B has a lower density of the sites indicated by "○" before step S103 compared to W3A, and removal of both the sites indicated by "○" and "×" proceeds more easily in step S103. Consequently, there are fewer sites on which the raw material gas of the fourth membrane W4 is adsorbed, and W3B exhibits film formation inhibition more easily than W3A.

[0037] Non-oxidizing gases are preferably used in plasma form. The gas used for plasma formation may be a reducing gas or an inert gas. Non-oxidizing gases are not specifically defined, but examples include plasma-formed H2O gas, plasma-formed H2 gas, plasma-formed NH3 gas, plasma-formed N2 gas, plasma-formed Ar gas, plasma-formed He gas, or plasma-formed mixed gases (including H2 gas and N2 gas).

[0038] When the first film W1 is a Si-containing film and the second film W2 is a metal-containing film, that is, when the first film W1 has material B and the second film W2 has material A, modifying the third film W3 may include supplying an oxidizing gas to the substrate W as a modifying gas. This makes the film formation inhibiting effect of the second part W3-2 of the third film W3 on the fourth film W4 more apparent than that of the first part W3-1.

[0039] When the first film W1 is a metal-containing film and the second film W2 is a Si-containing film, that is, when the first film W1 has material A and the second film W2 has material B, modifying the third film W3 involves supplying a non-oxidizing gas to the substrate W as a modifying gas. This makes the film formation inhibiting properties of the second part W3-2 of the third film W3 against the fourth film W4 more apparent than those of the first part W3-1 of the third film W3.

[0040] It is preferable to expose the substrate W to at least one of a vacuum atmosphere and an inert atmosphere without exposing it to the atmosphere from immediately after the formation of the third film W3 until immediately before the formation of the fourth film W4 (i.e., from immediately after step S102 until immediately before step S104). This prevents organic compounds contained in the atmosphere from contaminating the substrate surface Wa (for example, organic compounds adhering to and covering the substrate surface Wa), and prevents the effect of the third film W3 containing boron (the effect of the third film W3 inhibiting the formation of the fourth film W4, as described later) from being impaired.

[0041] In this specification, an atmospheric atmosphere is defined as an atmosphere with a pressure of normal pressure (approximately 101 kPa) and an atmosphere proportion of 95% to 100% by volume. An inert atmosphere is defined as an atmosphere with an atmosphere proportion of 5% or less by volume and an inert gas proportion of 95% to 100% by volume (preferably 98% to 100% by volume). The inert gas consists of at least one selected from N2 gas and noble gases (e.g., argon gas or helium gas). The pressure of the inert atmosphere is not particularly limited, but is, for example, normal pressure. The inert gas is a gas with controlled purity and is supplied, for example, from a cylinder.

[0042] Furthermore, in this specification, a vacuum atmosphere refers to an atmosphere with a pressure of 0 Pa to 10 kPa (preferably 0 Pa to 1 kPa). The vacuum atmosphere may include at least one selected from air, inert gas, hydrogen gas, and ammonia gas. The vacuum atmosphere may also be an atmosphere obtained by reducing the pressure of the air from atmospheric pressure to 10 kPa or less. By removing more than 90% of the air, most of the organic compounds contained in the air can be removed. However, it is preferable that the vacuum atmosphere is an inert atmosphere obtained by reducing the pressure of the air from atmospheric pressure to 10 kPa or less. The gas other than the air (e.g., inert gas, hydrogen gas, and ammonia gas) is a gas whose purity is controlled and is supplied, for example, from a cylinder.

[0043] Step S104 includes selectively forming a fourth film W4 on the first part W3-1 relative to the second part W3-2 of the third film W3, as shown in Figure 4. Unlike the second part W3-2, the first part W3-1 has almost no inhibitory effect on the formation of the fourth film W4, and the fourth film W4 is deposited on the first part W3-1. Step S104 also includes forming a fourth film W4 containing element X by alternately or simultaneously supplying a source gas containing halogens and non-halogen elements X and a reaction gas that reacts with adsorbents of the source gas to the substrate surface Wa.

[0044] The first film W1 is a conductive film, an insulating film, or a semiconductor film. The fourth film W4 is a conductive film, an insulating film, or a semiconductor film. The combination of the first film W1 and the fourth film W4 is not particularly limited. The first film W1 may be an insulating film and the fourth film W4 may be an insulating film. The first film W1 may be a conductive film and the fourth film W4 may be an insulating film. The first film W1 may be an insulating film and the fourth film W4 may be a conductive film. The first film W1 may be a conductive film and the fourth film W4 may be a conductive film.

[0045] Step S104, as shown in Figure 3, includes, for example, steps S104a to S104e. Step S104 only needs to include steps S104a and S104c; it does not need to include steps S104b, S104d, and S104e. Steps S104a to S104e will be described below.

[0046] Step S104a includes supplying a raw material gas to the substrate W. The raw material gas contains a halogen and an element X other than a halogen. The halogen is fluorine, chlorine, bromine, or iodine. Element X is not particularly limited, but is preferably a metallic element, and more preferably a transition metal element. Element X is, for example, Ti, W, V, Al, Mo, Sn, Hf, Ta, Nb, Zr, In, Ga, or Sb. Specific examples of raw material gases include TiCl4 gas, WCl6 gas, WF6 gas, VCl4 gas, AlCl3 gas, MoCl5 gas, SnCl4 gas, HfCl4 gas, TaCl5 gas, NbCl5 gas, ZrCl4 gas, InCl3 gas, GaCl3 gas, or SbCl3 gas. Element X may also be a semiconductor element, specifically Si or Ge. The raw material gas is silicon halide gas or germanium halide gas. Specific examples of silicon halogenated gases include SiCl4 gas, SiHCl3 gas, SiH2Cl2 gas, SiH3Cl gas, and Si2Cl6 gas. 、 Examples include Si2HCl5 gas, Si2Cl3CH3 gas, SiCl3CCl3 gas, SiCl3CH3 gas, or SiH2I2 gas. A specific example of germanium halide gas is GeCl4 gas. The source gas may be supplied together with a diluent gas. The diluent gas is, for example, Ar gas or N2 gas.

[0047] Step S104b includes supplying a purge gas to the substrate W. The purge gas purges any excess raw material gas that was not adsorbed on the substrate surface Wa in step S104a. As the purge gas, for example, a noble gas such as Ar gas or N2 gas can be used.

[0048] Step S104c includes supplying a reaction gas to the substrate W. The reaction gas reacts with element X contained in the adsorbed material of the raw material gas to form a fourth film W4 containing element X. Examples of reaction gases include oxygen-containing gases, nitrogen-containing gases, or hydrogen-containing gases. Oxygen-containing gases contain oxygen and form an oxide film of element X. Examples of oxygen-containing gases include O2 gas, O3 gas, CO2 gas, N2O gas, NO gas, or H2O gas. Nitrogen-containing gases contain nitrogen and form a nitride film of element X. Examples of nitrogen-containing gases include NH3 gas or N2H4 gas. Hydrogen-containing gases contain hydrogen and form a film (e.g., a metal film or a semiconductor film) mainly composed of element X. Examples of hydrogen-containing gases include H2 gas or H2S gas. The reaction gas may be supplied together with a diluent gas. Examples of diluent gases include Ar gas or N2 gas.

[0049] Step S104c may include plasmaizing the reaction gas, and may also include supplying the plasmaized reaction gas to the substrate W.

[0050] The reaction gas may be supplied not only in step S104c, but also in all of steps S104a to S104d. However, plasma formation of the reaction gas is performed only in step S104c. This is because plasma formation of the reaction gas makes it easier to react with adsorbed raw material gas on the substrate surface Wa.

[0051] Step S104c may also include supplying O3 gas to the substrate surface Wa as a reaction gas without plasma formation.

[0052] Step S104d includes supplying a purge gas to the substrate surface Wa. The purge gas purges any excess reaction gas that did not react with the substrate surface Wa in step S104c. As the purge gas, for example, a noble gas such as Ar gas or N2 gas can be used.

[0053] In step S104e, it is confirmed whether steps S104a to S104d above have been performed L times (where L is an integer greater than or equal to 1). L may be an integer greater than or equal to 2, and steps S104a to S104d may be repeated. The thickness of the fourth film W4 can be increased.

[0054] If the number of times steps S104a to S104d are performed is less than L (step S104e, NO), the thickness of the fourth film W4 is less than the target value, so steps S104a to S104d are performed again. L is preferably 200 or more, more preferably 300 or more. L is preferably 1000 or less.

[0055] On the other hand, if the number of times steps S104a to S104d are performed reaches L (step S104e, YES), the thickness of the fourth film W4 has reached the target value, and step S104 is terminated.

[0056] The method for forming the fourth film W4 shown in Figure 3 is the ALD (Atomic Layer Deposition) method, but the CVD (Chemical Vapor Deposition) method may also be used. In the ALD method, the supply of the raw material gas (step S104a) and the supply of the reaction gas (step S104c) are performed alternately. On the other hand, in the CVD method, the supply of the raw material gas and the reaction gas are performed simultaneously.

[0057] To inhibit the formation of the fourth film W4 on the surface of the second part W3-2 of the third film W3, it is important that the adsorption of the raw material gas onto the second part W3-2 is weak or nonexistent, and as a result, the adsorbed raw material gas on the surface of the second part W3-2 desorbs without advancing the film formation reaction (formation of the fourth film W4). Alternatively, it is important that the adsorption of the raw material gas onto the surface of the second part W3-2 does not occur, or that dissociation of the raw material gas on the surface of the second part W3-2 is unlikely to occur. If dissociation of the raw material gas occurs, the film formation reaction proceeds easily.

[0058] Since the third film W3 contains boron, and the second part W3-2 of the third film W3 is modified, it is thought that no adsorption of halides occurs on the second part W3-2, or if it does occur, it is weak, or that dissociation of halides is unlikely to occur. As a result, the formation of the fourth film W4 is inhibited on the surface of the second part W3-2.

[0059] On the other hand, it is thought that halides are strongly adsorbed on the first part W3-1 of the third film W3, or that dissociation of halides is likely to occur. As a result, it is thought that the formation of the fourth film W4 progresses on the surface of the first part W3-1.

[0060] Even if the third membrane W3 contains boron, if the second part W3-2 of the third membrane W3 is not modified, the adsorption inhibition of halides by boron is less likely to occur, and the raw material gas is adsorbed not only on the first part W3-1 of the third membrane W3 but also on the second part W3-2. The raw material gas adsorbed on the first part W3-1 and the second part W3-2 reacts with the reaction gas supplied in S104c, and the fourth membrane W4 is formed on both the first part W3-1 and the second part W3-2.

[0061] Furthermore, halides such as TiCl4 are less susceptible to decomposition by the heat of the substrate W compared to organometallic complexes such as Ti[N(CH3)2]4. If the source gas decomposes after being adsorbed onto the second part W3-2 of the third film W3, the formation of the fourth film W4 will proceed. Therefore, in order to inhibit the formation of the fourth film W4 on the surface of the second part W3-2, a halogen-containing gas is suitable as the source gas for the fourth film W4.

[0062] Furthermore, in plasma CVD, where both the halide and the reaction gas are plasma-activated, reactive species such as ions or radicals are generated from the dissociation of the halide. These reactive species generated from the halide are highly reactive, and it is thought that the film deposition reaction proceeds more easily not only on the surface of the first part W3-1 of the third film W3, but also on the surface of the second part W3-2. Therefore, it is preferable not to plasma-activate the source gas, and it is important to use thermal ALD, plasma ALD, or thermal CVD.

[0063] In steps S104a to S104d above, the temperature of the substrate W may be controlled to 100°C or higher in order to promote the desorption of the raw material gas on the surface of the second part W3-2 of the third film W3. If the temperature of the substrate W is below 100°C, the desorption of the raw material gas will not occur sufficiently on the surface of the second part W3-2, and the raw material gas will be physically adsorbed, causing the fourth film W4 to be formed on the surface of the second part W3-2 as well. The temperature of the substrate W is preferably 300°C or higher. The temperature of the substrate W is preferably 800°C or lower.

[0064] Step S105 includes checking whether the series of processes has been performed N times (where N is an integer of 1 or more). The series of processes includes the formation of the third film W3 (step S102), the modification of the third film W3 (step S103), and the formation of the fourth film W4 (step S104). This series of processes is also called the first cycle. If the number of times the first cycle has been performed is less than N (step S105, NO), the film thickness of the fourth film W4 is insufficient, so the first cycle is performed again. On the other hand, if the number of times the first cycle has been performed reaches N (step S105, YES), the current process is terminated. N is preferably an integer of 2 or more. If N is an integer of 2 or more, the film thickness of the fourth film W4 can be increased while replenishing the third film W3.

[0065] If N is an integer greater than or equal to 2, the first cycle is repeated multiple times. Step S102 from the second time onward includes forming the third film W3 again on both the fourth film W4 and the second part W3-2 of the third film W3, although this is not shown in the diagram. Note that in the first step S104, the third film W3 may become thin or disappear. If the third film W3 disappears, step S102 from the second time onward includes forming the third film W3 again on both the fourth film W4 and the second film W2.

[0066] The second and subsequent steps S104, although not shown in the diagram, include selectively forming a fourth film W4 again on the first part W3-1 relative to the second part W3-2 of the third film W3.

[0067] Next, with reference to Figure 6, a film deposition apparatus 100 for carrying out the above film deposition method will be described. As shown in Figure 6, the film deposition apparatus 100 has a first processing unit 200A, a second processing unit 200B, a third processing unit 200C, a transport unit 400, and a control unit 500. The first processing unit 200A carries out step S102 in Figure 1. The second processing unit 200B carries out step S103 in Figure 1. The third processing unit 200C carries out step S104 in Figure 1. The first processing unit 200A, the second processing unit 200B, and the third processing unit 200C may have the same structure or different structures. Note that the first processing unit 200A may carry out steps S102 to S104 in Figure 1. In this case, steps S102 to S104 are carried out inside the same processing container 210 (see Figure 7).

[0068] The transport unit 400 transports the substrate W to the first processing unit 200A, the second processing unit 200B, and the third processing unit 200C. The transport unit 400 has a first transport chamber 401 and a first transport mechanism 402. The internal atmosphere of the first transport chamber 401 is an atmospheric atmosphere. The first transport mechanism 402 is provided inside the first transport chamber 401. The first transport mechanism 402 includes an arm 403 for holding the substrate W and travels along a rail 404. The rail 404 extends in the direction of the arrangement of the carriers C.

[0069] Furthermore, the transport unit 400 includes a second transport chamber 411 and a second transport mechanism 412. The internal atmosphere of the second transport chamber 411 is a vacuum atmosphere. The second transport mechanism 412 is provided inside the second transport chamber 411. The second transport mechanism 412 includes an arm 413 for holding the substrate W, and the arm 413 is arranged to be movable in the vertical and horizontal directions and rotatable around a vertical axis. The first processing unit 200A, the second processing unit 200B, and the third processing unit 200C are connected to the second transport chamber 411 via different gate valves G.

[0070] Furthermore, the conveying section 400 has a load lock chamber 421 between the first conveying chamber 401 and the second conveying chamber 411. The internal atmosphere of the load lock chamber 421 is switched between a vacuum atmosphere and an atmospheric atmosphere by a pressure regulating mechanism (not shown). This allows the inside of the second conveying chamber 411 to always be maintained in a vacuum atmosphere. It also prevents gas from flowing from the first conveying chamber 401 into the second conveying chamber 411. Gate valves G are provided between the first conveying chamber 401 and the load lock chamber 421, and between the second conveying chamber 411 and the load lock chamber 421.

[0071] The control unit 500 is, for example, a computer and has an arithmetic unit 501 such as a CPU (Central Processing Unit) and a storage unit 502 such as memory. The storage unit 502 stores programs that control various processes performed in the film deposition apparatus 100. The control unit 500 controls the operation of the film deposition apparatus 100 by causing the arithmetic unit 501 to execute the programs stored in the storage unit 502. The control unit 500 controls the first processing unit 200A, the second processing unit 200B, the third processing unit 200C and the transport unit 400 to carry out the above-described film deposition method.

[0072] The control unit 500 includes electronic circuits such as a CPU, GPU (Graphics Processing Unit), FPGA (Field Programmable Gate Array), or ASIC (Application Specific Integrated Circuit), and performs various control operations described in this specification by executing instruction codes stored in memory or by designing circuits for special applications.

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

[0074] Next, the first processing unit 200A performs step S102 in Figure 1. After that, the second transport mechanism 412 removes the substrate W from the first processing unit 200A and transports the removed substrate W to the second processing unit 200B. During this time, the substrate surface Wa can be protected in a vacuum atmosphere, and contamination of the substrate surface Wa by organic compounds in the atmosphere can be suppressed.

[0075] Next, the second processing unit 200B performs step S103 in Figure 1. After that, the second transport mechanism 412 removes the substrate W from the second processing unit 200B and transports the removed substrate W to the third processing unit 200C. During this time, the substrate surface Wa can be protected in a vacuum atmosphere, and contamination of the substrate surface Wa by organic compounds in the atmosphere can be suppressed.

[0076] Next, the third processing unit 200C performs step S104 in Figure 1. Then, the second transport mechanism 412 removes the substrate W from the third processing unit 200C, transports the removed substrate W to the load lock chamber 421, and exits the load lock chamber 421. Subsequently, the internal atmosphere of the load lock chamber 421 is switched from a vacuum atmosphere to an atmospheric atmosphere. After that, the first transport mechanism 402 removes the substrate W from the load lock chamber 421 and places the removed substrate W into the carrier C. Then, the processing of the substrate W is completed.

[0077] As described above, the first processing unit 200A may also perform steps S102 to S104 in Figure 1. In this case, steps S102 to S104 are performed inside the same processing container 210 (see Figure 7). Therefore, in this case as well, the substrate surface Wa can be continuously exposed to at least one of a vacuum atmosphere and an inert atmosphere without being exposed to the atmosphere, and contamination of the substrate surface Wa by organic compounds in the atmosphere can be suppressed.

[0078] Next, the first processing unit 200A will be described with reference to Figure 7. Note that the second processing unit 200B and the third processing unit 200C are configured similarly to the first processing unit 200A, and therefore their illustrations and descriptions are omitted.

[0079] The first processing unit 200A includes a substantially cylindrical, airtight processing container 210. An exhaust chamber 211 is provided in the center of the bottom wall of the processing container 210. The exhaust chamber 211 has a shape that protrudes downward, for example, a substantially cylindrical shape. An exhaust pipe 212 is connected to the exhaust chamber 211, for example, on the side of the exhaust chamber 211.

[0080] An exhaust source 272 is connected to the exhaust piping 212 via a pressure controller 271. The pressure controller 271 includes a pressure regulating valve, such as a butterfly valve. The exhaust piping 212 is configured to reduce the pressure inside the processing container 210 by the exhaust source 272. The pressure controller 271 and the exhaust source 272 constitute a gas discharge mechanism 270 that discharges gas from inside the processing container 210.

[0081] A transport port 215 is provided on the side of the processing container 210. The transport port 215 is opened and closed by a gate valve G. The substrate W is loaded and unloaded between the processing container 210 and the second transport chamber 411 (see Figure 6) through the transport port 215.

[0082] A stage 220, which is a holding part for holding the substrate W, is provided inside the processing container 210. The stage 220 holds the substrate W horizontally with the substrate surface Wa facing upward. The stage 220 is formed in a substantially circular shape in plan view and is supported by a support member 221. A substantially circular recess 222 is formed on the surface of the stage 220 for placing a substrate W, for example, with a diameter of 300 mm. The recess 222 has an inner diameter slightly larger than the diameter of the substrate W. The depth of the recess 222 is set to be approximately the same as the thickness of the substrate W, 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 metallic material such as nickel (Ni). Instead of the recess 222, a guide ring for guiding the substrate W may be provided on the peripheral edge of the surface of the stage 220.

[0083] A lower electrode 223, for example, grounded, is embedded in the stage 220. A heating mechanism 224 is embedded below the lower electrode 223. The heating mechanism 224 is powered by a power supply unit (not shown) based on a control signal from the control unit 500 (see Figure 6), and heats the substrate W 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 raising and lowering the substrate W placed on the stage 220. The material of the lifting pins 231 may be, for example, ceramics such as alumina (Al2O3) or quartz. The lower ends of the lifting pins 231 are attached to a support plate 232. The support plate 232 is connected via a lifting shaft 233 to a lifting mechanism 234 located outside the processing container 210.

[0084] The lifting mechanism 234 is installed, for example, at the bottom of the exhaust chamber 211. The bellows 235 is provided between the opening 219 for the lifting shaft 233 formed on the lower surface of the exhaust chamber 211 and the lifting mechanism 234. The shape of the support plate 232 may be such that it can move up and down without interfering with the support member 221 of the stage 220. The lifting pin 231 is configured to move up and down between the upper surface of the stage 220 and the lower surface of the stage 220 by the lifting mechanism 234.

[0085] A gas supply unit 240 is provided on the top wall 217 of the processing container 210 via an insulating member 218. The gas supply unit 240 forms the 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 100kHz to 2.45GHz, preferably 450kHz to 100MHz, 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 a capacitively coupled plasma is generated. The plasma generation unit 250 that generates the plasma includes a matching unit 251 and a high-frequency power supply 252. Note that the plasma generation unit 250 is not limited to generating capacitively coupled plasma, but may generate other plasmas such as inductively coupled plasma or remote plasma. Note that in processes that do not generate plasma, it is not necessary for the gas supply unit 240 to form the upper electrode, and the lower electrode 223 is also unnecessary.

[0086] The gas supply unit 240 includes a hollow gas supply chamber 241. On the lower surface of the gas supply chamber 241, numerous holes 242 are evenly arranged, for example, to distribute and supply the processing gas into the processing container 210. Above the gas supply chamber 241 in the gas supply unit 240, for example, a heating mechanism 243 is embedded. The heating mechanism 243 is heated to a set temperature by being powered from a power supply unit (not shown) based on a control signal from the control unit 500.

[0087] A gas supply mechanism 260 is connected to the gas supply chamber 241 via a gas supply passage 261. The gas supply mechanism 260 supplies the gas used in the process shown in Figure 1 to the gas supply chamber 241 via the gas supply passage 261. Although not shown, the gas supply mechanism 260 includes individual piping for each type of gas, on-off valves installed in the middle of the individual piping, and flow controllers installed in the middle of the individual piping. When the on-off valve opens the individual piping, gas is supplied from the supply source to the gas supply passage 261. The amount of gas supplied is controlled by the flow controller. On the other hand, when the on-off valve closes the individual piping, the supply of gas from the supply source to the gas supply passage 261 is stopped.

[0088] [Examples] Examples are described below. Examples 2 and 3 below are examples, and Example 1 below is a comparative example.

[0089] Table 1 shows the processing conditions for Examples 1 to 3. Examples 1 to 3 had the same processing conditions except for the presence or absence of step S103 (reforming of the third film) and the type of reforming gas. In step S102, TDMAB was used as the second raw material gas, and only H2 gas was used as the second reaction gas. In step S104, Si2Cl6 gas was used as the raw material gas, and NH3 gas was used as the reaction gas. Although step S104 was a condition for forming a SiN film, the SiN film was converted to a SiON film by exposure to air after film formation.

[0090] [Table 1]

[0091] In Table 1, "ON" under "RF" means that the supply gas was plasma-generated using high-frequency power. "OFF" under "RF" means that plasma generation of the supply gas was not performed.

[0092] Figure 8 shows a TEM image of the substrate after processing under the conditions of Example 1 shown in Table 1. Figure 9 shows a TEM image of the substrate after processing under the conditions of Example 2 shown in Table 1. Figure 10 shows a TEM image of the substrate after processing under the conditions of Example 3 shown in Table 1. As shown in Figures 8 to 10, in step S101, a substrate was prepared having an SiO film and a Ru film in different regions of the substrate surface. As a result, under the conditions of Example 1, where step S103 is not performed, a SiON film was formed on both the SiO film and the Ru film, as shown in Figure 8. On the other hand, under the conditions of Example 2, where step S103 is performed using plasma-treated O2 gas as the reforming gas, a SiON film was selectively formed on the SiO film, as shown in Figure 9. Furthermore, under the conditions of Example 3, where step S103 is performed using plasma-treated H2O gas as the reforming gas, a SiON film was selectively formed on the Ru film, as shown in Figure 10.

[0093] Figures 8 to 10 show that step S103 improves the selectivity of selective film formation. Furthermore, Figures 9 to 10 show that changing the type of reformed gas in step S103 changes the region where the SiON film is formed.

[0094] In Figures 8 to 10, the third film containing boron was thin and almost invisible. However, as mentioned above, by changing the type of reformed gas, the region where the SiON film was formed could be changed, suggesting that the third film containing boron was formed on both the SiON film and the Ru film.

[0095] While embodiments of the film deposition method and film deposition apparatus relating to this disclosure have been described above, this 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, too, naturally fall within the technical scope of this disclosure. [Explanation of Symbols]

[0096] W board W1 1st membrane W2 Second membrane W3 3rd membrane W3-1 Part 1 W3-2 Part 2 W4 4th membrane

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