Film formation method and film formation device

Abstract

A film formation method according to the present invention comprises: preparing a substrate that comprises a laminated film, which includes a boron-containing first film and a second film formed of a material different from that of the first film, and a recessed part formed in a surface of the laminated film so as to penetrate the first film and the second film; and selectively forming, inside the recessed part, a target film on a side surface of the second film and not on a side surface of the first film. The target film contains a desired element X. The formation of the target film includes supplying the following to the substrate: a feedstock gas containing a compound of the element X and a halogen; and a reactive gas that reacts with an adsorbate of the feedstock gas.

Description

Film forming method and film forming apparatus

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

[0002] The processing method described in Patent Document 1 includes the steps of preparing a substrate having a recess on its surface, the recess being made up of a Si film and a SiGe film, forming a film formation suppression layer on the surface of the Si film that makes up the recess, and forming a SiOC film on the surface of the SiGe film that makes up the recess.

[0003] Japanese Patent Application Publication No. 2023-123717

[0004] One embodiment of the present disclosure provides a technique for selectively forming a target film on a side surface of a second film relative to a side surface of a first film inside a recess.

[0005] A film formation method according to one embodiment of the present disclosure includes: preparing a substrate having a stacked film including a first film containing boron and a second film formed of a material different from the first film; and a recess formed on a surface of the stacked film penetrating the first film and the second film; and forming a target film inside the recess selectively on a side surface of the second film relative to a side surface of the first film. The target film contains a desired element X. Forming the target film includes supplying to the substrate a source gas containing a compound of the element X and a halogen, and a reactive gas that reacts with an adsorbate of the source gas.

[0006] According to an embodiment of the present disclosure, a target film can be selectively formed on the side surface of the second film relative to the side surface of the first film inside the recess.

[0007] FIG. 1 is a flowchart showing a film formation method according to an embodiment. FIG. 2 is a flowchart showing an example of S102 in FIG. 1 . FIG. 3 is a cross-sectional view showing a film formation method according to an embodiment. FIG. 4 is a cross-sectional view showing a modification of FIG. 3 . FIG. 5 is a flowchart showing S102 of a film formation method according to a first modification. FIG. 6 is a cross-sectional view showing a film formation method according to the first modification. FIG. 7 is a flowchart showing a film formation method according to a second modification. FIG. 8 is a cross-sectional view showing a film formation method according to the second modification. FIG. 9 is a flowchart showing a film formation method according to a third modification. FIG. 10 is a cross-sectional view showing a film formation method according to the third modification. FIG. 11 is a plan view showing a film formation apparatus according to an embodiment. FIG. 12 is a cross-sectional view showing an example of a first processing unit.

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same or similar components are denoted by the same reference numerals, and their description may be omitted. In the specification, the symbol "to" indicating a numerical range means that the numerical values ​​before and after it are included as the lower and upper limits. The numerical range includes the range rounded up or down.

[0009] First, a film formation method according to one embodiment will be described with reference to Figures 1 to 4. The film formation method includes, for example, steps S101 to S102 shown in Figure 1. Note that the film formation method may include steps other than steps S101 to S102 shown in Figure 1.

[0010] Step S101 includes preparing a substrate W (see, for example, FIGS. 3 and 4). The substrate W has a laminated film W0. The laminated film W0 is formed on a base substrate (not shown). 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 laminated film W0 includes a first film W1 containing boron (B) and a second film W2 formed of a material different from that of the first film W1. The laminated film W0 may also include a third film W3 in addition to the first film W1 and the second film W2. The third film W3 is formed of a material different from that of the first film W1 and the second film W2. The material of the third film W3 may be selected from the candidate materials for the second film W2 described below.

[0012] The laminated film W0 preferably has a plurality of first repeat elements including a first film W1 and a second film W2. The first repeat elements may have a third film W3 in addition to the first film W1 and the second film W2. When the substrate W is used for a NAND flash memory, the number of first repeat elements is preferably 100 to 1000. The substrate W may also be used for a 3D DRAM (Dynamic Random Access Memory), a 3D FeRAM (Ferroelectric Random Access Memory), etc.

[0013] 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 BC 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. Films other than a BN film, such as a BNC film, similarly mean that they contain the respective elements and are not limited to a stoichiometric ratio.

[0014] 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. Note that the third film W3, like the second film W2, also does not substantially contain B. The third film W3 may also be any of an insulating film, a conductive film, and a semiconductor film.

[0015] The insulating film serving as the second film W2 is not particularly limited, but may be, for example, a 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 refers to a film containing silicon (Si) and oxygen (O). The atomic ratio of Si to O in a SiO film is usually 1:2, but is not limited to 1:2. Similarly, the SiN film, the SiOC film, the SiON film, the SiOCN film, the AlO film, the ZrO film, the HfO film, and the TiO film also refer to the inclusion of each element and are not limited to a 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.

[0016] The semiconductor film as the second film W2 is not particularly limited, but may be, for example, a Si film, a SiGe film, a GaN film, a ZTO (Zinc Tin Oxide) film, or an IGZO (Indium Gallium Zinc Oxide) film. The semiconductor film may be any of a single crystal film, a polycrystalline film, and an amorphous film. Alternatively, a graphene film, a WS film, etc. ２ Membrane, WSe ２ membrane, MoS ２ The semiconductor film may be a two-dimensional semiconductor film such as a film.

[0017] The conductive film as the second film W2 is, for example, a metal film. The metal film is not particularly limited, but may be, 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 may be, for example, a TiN film or a TaN film. Here, the TiN film refers to a film containing titanium (Ti) and nitrogen (N). The atomic ratio of Ti to N in a TiN film is usually 1:1, but is not limited to 1:1. Similarly, the TaN film refers to a film containing each element and is not limited to a stoichiometric ratio.

[0018] The substrate W has a recess WA formed on the surface of the stacked film W0, penetrating the first film W1 and the second film W2. The recess WA is, for example, a trench or a hole. The recess WA may penetrate one or more first repeat elements, but preferably penetrates multiple first repeat elements. The side surface of the recess WA includes the side surface of the first film W1 and the side surface of the second film W2. The side surface of the first film W1 and the side surface of the second film W2 may be flush with each other and may not have a step. The side surface of the recess WA may include the side surface of the third film W3 in addition to the side surface of the first film W1 and the side surface of the second film W2.

[0019] The side surface of the recess WA preferably has a plurality of second repeat elements including the side surfaces of the first film W1 and the second film W2. The number of second repeat elements is equal to or less than the number of first repeat elements. The number of second repeat elements may be the same as or less than the number of first repeat elements. When the stacked film W0 is for a NAND-type flash memory, the number of second repeat elements is preferably 100 to 1000. The second repeat element may have a side surface of the third film W3 in addition to the side surfaces of the first film W1 and the second film W2.

[0020] Step S102 includes selectively forming a target film WB on the side surface of the second film W2 relative to the side surface of the first film W1 inside the recess WA (see FIGS. 3 and 4, etc.). The target film WB contains a desired element X. Step S102 includes supplying to the substrate W a source gas containing a compound of the element X and a halogen, and a reactive gas that reacts with an adsorbate of the source gas. The source gas and the reactive gas are supplied alternately or simultaneously.

[0021] 2, step S102 includes, for example, steps S102a to S102e. Note that step S102 may include at least steps S102a, S102c, and S102e, and does not necessarily include steps S102b and S102d. Steps S102a to S102e will be described below.

[0022] Step S102a includes supplying a source gas to the substrate W. The source gas contains a compound of an element X and a halogen. The halogen is fluorine, chlorine, bromine, or iodine. The element X is not particularly limited, but is preferably a metal element, and more preferably a transition metal element. The element X is, for example, Ti, W, V, Al, Mo, Sn, Hf, Ta, Nb, Zr, In, Ga, or Sb. A specific example of the source gas is TiCl. ４ Gas, WCl ６ Gas, WF ６ Gas, VCl ４ Gas, AlCl ３ Gas, MoCl ５ Gas, SnCl ４ Gas, HfCl ４ Gas, TaCl ５ Gas, NbCl ５ Gas, ZrCl ４ Gas, InCl ３ Gas, GaCl ３ gas or SbCl ３ 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 silicon halide gas include SiCl ４ Gas, SiHCl ３ Gas, SiH ２ Cl ２ Gas, SiH ３ Cl gas, Si ２ Cl ６ gas 、 Si ２ HCl ５ Gas, Si ２ Cl ３ CH ３ Gas, SiCl ３ CCl ３ Gas, SiCl ３ CH ３ gas, or SiH ２ I ２ Specific examples of germanium halide gas include GeCl ４ The source gas may be supplied together with a dilution gas. The dilution gas may be, for example, Ar gas or N ２It's gas.

[0023] Step S102b includes supplying a purge gas to the substrate W. The purge gas purges excess source gas that has not been adsorbed onto the substrate W in step S102a. The purge gas may be, for example, a rare gas such as Ar gas or N ２ A gas is used.

[0024] Step S102c includes supplying a reactive gas to the substrate W. The reactive gas reacts with an element X contained in the adsorbate of the source gas to form a target film WB containing the element X. Examples of the reactive gas include an oxygen-containing gas, a nitrogen-containing gas, and a hydrogen-containing gas. The oxygen-containing gas contains oxygen and forms an oxide film of the element X. The oxygen-containing gas is, for example, O ２ Gas, O ３ Gas, CO ２ Gas, N ２ O gas, NO gas, or H ２ The nitrogen-containing gas contains nitrogen and forms a nitride film of element X. The nitrogen-containing gas is, for example, NH ３ Gas or N ２ H ４ The hydrogen-containing gas contains hydrogen and forms a film (for example, a metal film or a semiconductor film) containing the element X as a main component. The hydrogen-containing gas is, for example, H ２ Gas or H ２ The reactive gas may be supplied together with a dilution gas, such as Ar gas or N ２ It's gas.

[0025] Step S102c may include converting the reactive gas into plasma, or may include supplying the plasmatized reactive gas to the substrate W. Converting the reactive gas into plasma can promote the formation of the target film WB.

[0026] The reactive gas may be supplied not only in step S102c but also in all of steps S102a to S102d. However, the reactive gas is turned into plasma only in step S102c. This is because the reactive gas becomes more likely to react with adsorbates of the source gas on the substrate W when turned into plasma.

[0027] Step S102c uses O as a reactive gas. ３ This may include supplying the gas to the substrate W without converting it into plasma.

[0028] Step S102d includes supplying a purge gas to the substrate W. The purge gas purges excess reactive gas that did not react with the substrate W in step S102c. The purge gas may be, for example, a rare gas such as Ar gas or N ２ A gas is used.

[0029] Step S102e includes checking whether the first cycle including steps S102a to S102d has been performed L times (L is an integer equal to or greater than 1). L may be an integer equal to or greater than 2, and the first cycle may be repeatedly performed multiple times. This allows the film thickness of the target film WB to be increased.

[0030] If the first cycle has been performed less than L times (step S102e, NO), the film thickness of the target film WB is less than the target value, so the first cycle is performed again. L is preferably 100 or more, more preferably 200 or more. L is preferably 1000 or less.

[0031] On the other hand, if the number of times the first cycle has been performed reaches L (step S102e, YES), the film thickness of the target film WB has reached the target value, and the current process ends.

[0032] 2 is an atomic layer deposition (ALD) method, but may be a chemical vapor deposition (CVD) method. In the ALD method, a source gas is supplied (step S102a) and a reactant gas is supplied (step S102c) alternately. On the other hand, in the CVD method, the source gas and the reactant gas are supplied simultaneously.

[0033] To inhibit the formation of the target film WB on the side surface of the first film W1, it is important that the adsorption of the source gas to the first film W1 is weak, and as a result, the adsorbed material of the source gas is desorbed on the side surface of the first film W1 without advancing the film formation reaction (formation of the target film WB). Alternatively, it is important that the source gas is not adsorbed on the side surface of the first film W1, or that dissociation of the source gas is unlikely to occur on the side surface of the first film W1. If dissociation of the source gas occurs, the film formation reaction is likely to proceed.

[0034] Since the first film W1 contains boron, it is thought that adsorption of halides does not occur on the side surfaces of the first film W1, or if it does occur, it is weak, or that dissociation of halides is difficult to occur, and as a result, the formation of the target film WB is inhibited on the side surfaces of the first film W1.

[0035] On the other hand, since the second film W2 does not substantially contain boron, it is believed that halides are strongly adsorbed to the side surfaces of the second film W2 or that dissociation of halides occurs easily, and as a result, it is believed that the formation of the target film WB progresses on the side surfaces of the second film W2.

[0036] Also, TiCl ４ Halides such as Ti[N(CH ３ ) ２ ] ４ Compared to organometallic complexes such as those mentioned above, the source gas is less likely to decompose due to the heat of the substrate W. If the source gas decomposes after being adsorbed onto the first film W1, the formation of the target film WB will proceed. Therefore, in order to inhibit the formation of the target film WB on the side surface of the first film W1, a gas containing a halogen is suitable as the source gas for the target film WB.

[0037] Furthermore, in the plasma CVD method in which both the halide and the reactive gas are converted into plasma, active species such as ions or radicals are generated by dissociation of the halide. The active species generated from the halide are highly reactive, and it is thought that the film formation reaction is likely to proceed not only on the side surface of the second film W2 but also on the side surface of the first film W1. Therefore, it is preferable not to convert the source gas into plasma, and it is important to use the thermal ALD method, the plasma ALD method, or the thermal CVD method.

[0038] In steps S102a to S102d, the temperature of the substrate W may be controlled to 100°C or higher to promote desorption of the source gas from the side surface of 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 side surface of the first film W1, resulting in physical adsorption of the source gas, and the target film WB will also be formed on the side surface of the first film W1. The temperature of the substrate W is preferably 300°C or higher. The temperature of the substrate W is preferably 800°C or lower.

[0039] NAND flash memory is fabricated by forming recesses in a laminated film that alternately includes SiO and SiN films. To increase the density of memory elements, the total number of films constituting the laminated film is increasing. Furthermore, to thin the laminated film, it is desirable to reduce the thickness of the SiO and SiN films.

[0040] The charge trapping film that constitutes the memory cell is usually formed as a continuous film inside the recess. In this case, if the thickness of the SiO film and SiN film is reduced, the memory cells become closer to each other. As a result, electrical interference can deteriorate the device characteristics of the memory cells.

[0041] In order to reduce the film thickness without deteriorating the element characteristics of the memory cell, it is conceivable to separate the charge trap film via an insulating film. For example, if a structure in which an SiO film protrudes from the side surface of an SiN film is formed inside the recess, a charge trap film is formed on the side surface of the SiN film, and the charge trap film is separated by the SiO film, electrical interference can be suppressed.

[0042] One method for fabricating a structure in which the SiO film protrudes from the side surface of the SiN film inside the recess is to selectively etch the side surface of the SiN film. However, it is difficult to uniformly etch the side surfaces of multiple SiN films that are repeatedly arranged in the depth direction inside the recess.

[0043] One possible method for fabricating a structure in which SiO films protrude from the side surfaces of SiN films inside a recess is to selectively form an inhibitor film on the side surfaces of the SiN film and then selectively form an insulating film on the side surfaces of the SiO film. However, it is difficult to form an inhibitor film evenly on the side surfaces of multiple SiN films repeatedly arranged in the depth direction inside the recess.

[0044] According to this embodiment, the first film W1 functions as an inhibitory film that inhibits the formation of the target film WB. The inhibitory film is formed before the formation of the recess WA. The recess WA is formed by penetrating the previously formed inhibitory film. Unlike when the inhibitor is supplied after the recess WA is formed, an inhibitory side surface can be prepared regardless of the depth from the surface of the laminated film WO, thereby improving the selectivity of the target film WB. Note that when the inhibitory film is formed after the recess WA is formed, as in Patent Document 1, the deeper the depth from the surface of the laminated film WO, the more difficult it is to form the inhibitory film, and the more likely it is that the selectivity of the target film WB will be compromised. Furthermore, if the supply time of the inhibitor is extended to form an inhibitory film at the bottom of the recess WA, the inhibitor is likely to adsorb to the side surface at the top of the recess WA where the inhibitory film is not desired to be formed, and the selectivity of the target film WB will be compromised.

[0045] Furthermore, according to this embodiment, the recess WA is formed penetrating the first film W1 and the second film W2, so that the area inside the recess WA can be clearly divided into an area that has an inhibitory effect and an area that does not have an inhibitory effect. Furthermore, according to this embodiment, when the side surface of the recess WA has multiple second repeating elements, the same inhibitory effect can be imparted to the multiple second repeating elements. These effects are more pronounced the deeper the bottom of the recess WA. The depth of the bottom of the recess WA is preferably 1 μm or more, more preferably 3 μm or more.

[0046] 4, when the side surface of the recess WA has a side surface of the third film W3 in addition to the side surface of the first film W1 and the side surface of the second film W2, the target film WB may be formed on the side surface of the third film W3 in addition to the side surface of the second film W2. However, it is also possible to selectively form the target film WB only on the side surface of the second film W2.

[0047] For example, if the incubation time of the target film WB on the side surface of the second film W2 is shorter than the incubation time of the target film WB on the side surface of the third film W3, it is possible to selectively form the target film WB only on the side surface of the second film W2. The incubation time is the time difference between the start of the film formation process (e.g., the start of supply of the source gas or the reactant gas) and the actual start of film formation.

[0048] The laminated film W0 preferably has a first film W1 on the surface where the recess WA is formed. In other words, the top layer (the last layer to be formed) of the laminated film W0 is preferably the first film W1. The top layer, the first film W1, is exposed on the surface of the laminated film W0 and limits the formation of the target film WB on the surface of the laminated film W0. Therefore, the target film WB can be selectively formed inside the recess WA.

[0049] When fabricating a NAND flash memory using the technology disclosed herein, it is possible to use a B-containing film instead of a SiN film, and to use a laminated film W0 in which a B-containing film and a SiO film are alternately stacked. The recess WA is formed by penetrating the B-containing film formed in advance. An inhibiting side surface can be prepared regardless of the depth from the surface of the laminated film W0, and an insulating film can be selectively formed on the side surface of the SiO film.

[0050] Next, a film forming method according to a first modification will be described with reference to Figures 5 and 6. Differences from the above embodiment will be mainly described below. Step S102 may include steps S102f to S102g in addition to steps S102a to S102e, as shown in Figure 5.

[0051] 6, the selectivity of the target film WB in steps S102a to S102e is not perfect, and the target film WB may also be formed on the side surface of the first film W1. The target film WB formed on the side surface of the first film W1 is thinner than the target film WB formed on the side surface of the second film W2. The target film WB may cover only a portion of the side surface of the first film W1.

[0052] Step S102f includes supplying an etching gas to the substrate W. The etching gas etches the target film WB formed on the side surface of the first film W1. This allows the side surface of the first film W1 to be exposed as shown in FIG. 6, thereby improving the selectivity of the target film WB in subsequent steps S102a to S102e.

[0053] The etching gas etches not only the target film WB formed on the side surface of the first film W1 but also the target film WB formed on the side surface of the second film W2. The target film WB formed on the side surface of the second film W2 is thicker than the target film WB formed on the side surface of the first film W1. Therefore, the side surface of the first film W1 is exposed, and the target film WB can remain on the side surface of the second film W2.

[0054] The etching gas may etch the target film WB formed on the side surface of the first film W1, and then etch the first film W1. Because the first film W1 spreads laterally, it remains even when etched from the side. By exposing the side surface of the first film W1, steps S102a to S102e can be performed again without forming a new inhibitor film. Note that if the inhibitor is supplied after the recess WA is formed, the inhibitor film adsorbed to the side surface of the first film W1 may be lost during etching.

[0055] Step S102f may be performed before the target film WB grows from an island shape to a film shape on the side surface of the first film W1, which makes it easier to expose the side surface of the first film W1.

[0056] Step S102g includes checking whether the second cycle including steps S102a to S102f has been performed M times (M is an integer equal to or greater than 1). M may be an integer equal to or greater than 2, and the second cycle may be repeatedly performed multiple times. This allows the film thickness of the target film WB to be increased.

[0057] If the number of times the second cycle has been performed is less than M (step S102g, NO), the film thickness of the target film WB is less than the target value, so the second cycle is performed again. M is preferably 3 or more, more preferably 5 or more. M is preferably 10 or less.

[0058] On the other hand, if the number of times the second cycle has been performed reaches M (step S102g, YES), the film thickness of the target film WB has reached the target value, and the current process ends.

[0059] Next, a film forming method according to a second modified example will be described with reference to FIGS. 7 and 8. Differences from the above embodiment and the first modified example will be mainly described below. As shown in FIG. 7, the film forming method may include step S103 after step S101 and before step S102. In step S101, the side surface of the first film W1 and the side surface of the second film W2 may be flush with each other.

[0060] Step S103 includes selectively etching the side surface of the second film W2 relative to the side surface of the first film W1 inside the recess WA. As a result, the side surface of the second film W2 is recessed relative to the side surface of the first film W1, as shown in FIG. 8. In other words, a structure is obtained in which the first film W1 protrudes laterally from the side surface of the second film W2.

[0061] The etching gas or etching solution used in step S103 is appropriately selected depending on the combination of the materials of the first film W1 and the second film W2. For example, if the first film W1 is a BN film and the second film W2 is a SiO film, the etching gas or etching solution may contain HF. HF is considered to selectively etch the SiO film relative to the BN film.

[0062] Step S102 following step S103 includes forming the target film WB while sandwiching it between adjacent first films W1. This prevents the target film WB from growing beyond the target film WB. If the side surfaces of the first film W1 and the second film W2 are flush with each other, the target film WB may grow beyond the side surface of the second film W2 toward the side surface of the first film W1.

[0063] The target film WB may have a multi-layer structure, and may form, for example, a memory cell. The memory cell may have, for example, a SiO film, a SiN film, and an AlO film or HfO film. The memory cell is formed on the side of the second film W2. The first film W1 functions as an insulating film that electrically insulates adjacent memory cells.

[0064] When the side surfaces of the first film W1 and the second film W2 are flush with each other, the target film WB may have a multi-layer structure. When the side surfaces of the first film W1 and the second film W2 are flush with each other, the target film WB may form a memory cell.

[0065] Next, a film forming method according to a third modified example will be described with reference to FIGS. 9 and 10. Differences from the above embodiment, the first modified example, and the second modified example will be mainly described below. As shown in FIG. 9, the film forming method may include step S104 after step S101 and before step S102. In step S101, the side surface of the first film W1 and the side surface of the second film W2 may be flush with each other.

[0066] Step S104 includes selectively etching the side surface of the first film W1 relative to the side surface of the second film W2 inside the recess WA. As a result, the side surface of the first film W1 is recessed relative to the side surface of the second film W2, as shown in Figure 10. In other words, a structure is obtained in which the second film W2 protrudes laterally from the side surface of the first film W1.

[0067] The etching gas or etching solution used in step S104 is appropriately selected depending on the combination of the material of the first film W1 and the material of the second film W2. For example, when the first film W1 is a BN film and the second film W2 is a SiO film, the etching gas is F ２ , ClF ３ or Cl ２ F ２ , ClF ３ or Cl ２ It is believed that the BN film is selectively etched relative to the SiO film.

[0068] Step S102 following step S104 includes forming a target film WB on a portion of the second film W2 that protrudes laterally from the side surface of the first film W1. Even if the portion of the second film W2 that protrudes laterally from the side surface of the first film W1 is etched in step S104, the shape of the etched portion can be corrected by the target film WB.

[0069] 1, 7, or 9, the film formation method may include steps other than steps S101 to S104. For example, the film formation method may include a step of removing the first film W1 or the second film W2 by wet etching or the like after forming the target film WB. The film formation method may also include a step of filling a space created by removing the first film W1 or the second film W2 with a second target film. The second target film functions as, for example, wiring.

[0070] Next, a film forming apparatus 100 for carrying out the above-described film forming method will be described with reference to FIG. 11 . As shown in FIG. 11 , the film forming apparatus 100 includes a first processing unit 200A, a transport unit 400, and a control unit 500. The first processing unit 200A performs step S102 of FIG. 1 . The film forming apparatus 100 may also include a second processing unit that performs step S103 of FIG. 7 . The film forming apparatus 100 may also include a third processing unit that performs step S104 of FIG. 9 . However, the first processing unit 200A may also perform at least one of step S103 of FIG. 7 and step S104 of FIG. 9 .

[0071] The transport unit 400 transports substrates W to the first processing unit 200A. 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 atmospheric. The first transport mechanism 402 is provided inside the first transport chamber 401. The first transport mechanism 402 includes an arm 403 that holds the substrate W, and travels along rails 404. The rails 404 extend in the arrangement direction of the carriers C.

[0072] The transfer unit 400 also has a second transfer chamber 411 and a second transfer mechanism 412. The internal atmosphere of the second transfer chamber 411 is a vacuum atmosphere. The second transfer mechanism 412 is provided inside the second transfer chamber 411. The second transfer mechanism 412 includes an arm 413 that holds the substrate W, and the arm 413 is arranged to be movable vertically and horizontally and rotatable about a vertical axis. The second transfer chamber 411 is connected to the first processing unit 200A via a gate valve G.

[0073] Furthermore, the transfer unit 400 has a load lock chamber 421 between the first transfer chamber 401 and the second transfer chamber 411. The internal atmosphere of the load lock chamber 421 can be switched between a vacuum atmosphere and an atmospheric atmosphere by a pressure adjustment mechanism (not shown). This allows the interior of the second transfer chamber 411 to be constantly maintained in a vacuum atmosphere. Also, it is possible to prevent gas from flowing from the first transfer chamber 401 into the second transfer chamber 411. Gate valves G are provided between the first transfer chamber 401 and the load lock chamber 421, and between the second transfer chamber 411 and the load lock chamber 421.

[0074] The control unit 500 is, for example, a computer, and includes an arithmetic unit 501 such as a CPU (Central Processing Unit) and a storage unit 502 such as a memory. The storage unit 502 stores programs that control various processes executed in the film forming apparatus 100. The control unit 500 controls the operation of the film forming apparatus 100 by causing the arithmetic unit 501 to execute the programs stored in the storage unit 502. The control unit 500 controls the first processing unit 200A and the transport unit 400 to perform the above-described film forming method.

[0075] The program, i.e., a computer program product, may be supplied in a form recorded on a removable storage medium such as a memory card, an optical disk, or a hard disk drive (HDD). The control unit 500 reads the program from the storage medium and stores it in the storage unit 502. The storage unit 502 includes a storage medium such as an HDD, a solid state drive (SDD), or an electronically erasable programmable read-only memory (EEPROM). The program may be written in advance to the storage medium of the storage unit 502. The control unit 500 may also obtain the program distributed by a remote server device or the like via a network or other communication.

[0076] The control unit 500 includes electronic circuits such as a CPU, a GPU (Graphics Processing Unit), an FPGA (Field Programmable Gate Array), or an ASIC (Application Specific Integrated Circuit), and performs the various control operations described in this specification by executing instruction codes stored in a storage medium such as a memory, or by being a circuit designed for a specific application.

[0077] Next, the operation of the film forming 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 from the load lock chamber 421. Next, the internal atmosphere of the load lock chamber 421 is switched from the air atmosphere to a vacuum atmosphere. Thereafter, the second 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.

[0078] Next, the first processing unit 200A performs step S102 in Fig. 1. Thereafter, the second transport mechanism 412 removes the substrate W from the first processing unit 200A, transports the removed substrate W to the load lock chamber 421, and exits from the load lock chamber 421. The internal atmosphere of the load lock chamber 421 is then switched from a vacuum atmosphere to an atmospheric atmosphere. Thereafter, the first transport mechanism 402 removes the substrate W from the load lock chamber 421 and stores the removed substrate W in the carrier C. Then, the processing of the substrate W is completed.

[0079] Next, the first processing unit 200A will be described with reference to FIG. 12 . The first processing unit 200A includes a substantially cylindrical, airtight processing vessel 210. An exhaust chamber 211 is provided in the center of the bottom wall of the processing vessel 210. The exhaust chamber 211 has, for example, a substantially cylindrical shape that protrudes downward. An exhaust pipe 212 is connected to the exhaust chamber 211, for example, at a side surface of the exhaust chamber 211.

[0080] An exhaust source 272 is connected to the exhaust pipe 212 via a pressure controller 271. The pressure controller 271 includes a pressure adjustment valve such as a butterfly valve. The exhaust pipe 212 is configured so that the pressure inside the processing vessel 210 can be reduced by the exhaust source 272. The pressure controller 271 and the exhaust source 272 constitute a gas exhaust mechanism 270 that exhausts gas inside the processing vessel 210.

[0081] A transfer port 215 is provided on the side surface of the processing vessel 210. The transfer port 215 is opened and closed by a gate valve G. The substrate W is transferred in and out between the processing vessel 210 and the second transfer chamber 411 (see FIG. 11 ) via the transfer port 215.

[0082] A stage 220, which serves as a holder for holding a substrate W, is provided within the processing vessel 210. The stage 220 holds the substrate W horizontally with the surface of the substrate W on which the recess WA is formed facing upward. The stage 220 is formed in a substantially circular shape in a plan view and is supported by a support member 221. A substantially circular recess 222 for placing a substrate W having a diameter of, for example, 300 mm is formed on the surface of the stage 220. The recess 222 has an inner diameter slightly larger than the diameter of the substrate W. The depth of the recess 222 is configured to be substantially the same as the thickness of the substrate W, for example. The stage 220 is formed of a ceramic material such as aluminum nitride (AlN). Alternatively, the stage 220 may be formed of a metal material such as nickel (Ni). Note that instead of the recess 222, a guide ring for guiding the substrate W may be provided around the periphery of the surface of the stage 220.

[0083] A grounded lower electrode 223, for example, is embedded in the stage 220. A heating mechanism 224 is embedded below the lower electrode 223. The heating mechanism 224 receives power from a power supply unit (not shown) based on a control signal from the control unit 500 (see FIG. 11), thereby heating 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 (for example, three) lifting pins 231 for holding and lifting up and down the substrate W placed on the stage 220. The lifting pins 231 are made of a material such as alumina (Al ２ O ３ The lift pins 231 may be made of ceramics such as quartz or the like. The lower ends of the lift pins 231 are attached to a support plate 232. The support plate 232 is connected to a lift mechanism 234 provided outside the processing vessel 210 via a lift shaft 233.

[0084] The lifting mechanism 234 is installed, for example, below the exhaust chamber 211. The bellows 235 is provided between the lifting mechanism 234 and an opening 219 for the lifting shaft 233 formed in the lower surface of the exhaust chamber 211. The support plate 232 may be shaped so that it can be raised and lowered without interfering with the support member 221 of the stage 220. The lifting pins 231 are configured to be able to be raised and lowered by the lifting mechanism 234 between above and below the surface of the stage 220.

[0085] A gas supply unit 240 is provided on the ceiling wall 217 of the processing vessel 210 via an insulating member 218. The gas supply unit 240 serves as an upper electrode and faces the lower electrode 223. A high-frequency power supply 252 is connected to the gas supply unit 240 via a matching unit 251. By supplying high-frequency power of 100 kHz to 2.45 GHz, preferably 450 kHz to 100 MHz, from the high-frequency power supply 252 to the upper electrode (gas supply unit 240), a high-frequency electric field is generated between the upper electrode (gas supply unit 240) and the lower electrode 223, thereby generating capacitively coupled plasma. A plasma generation unit 250 that generates plasma includes the matching unit 251 and the high-frequency power supply 252. Note that the plasma generation unit 250 is not limited to capacitively coupled plasma, and may generate other types of plasma, such as inductively coupled plasma or remote plasma. Note that in steps that do not generate plasma, the gas supply unit 240 does not need to serve as an upper electrode, and the lower electrode 223 is also not required.

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

[0087] A gas supply mechanism 260 is connected to the gas supply chamber 241 via a gas supply path 261. The gas supply mechanism 260 supplies gases to be used in desired steps in FIG. 1 , FIG. 2 , FIG. 5 , FIG. 7 , or FIG. 9 to the gas supply chamber 241 via the gas supply path 261. Although not shown, the gas supply mechanism 260 includes individual pipes for each type of gas, on-off valves provided midway through the individual pipes, and flow rate controllers provided midway through the individual pipes. When the on-off valves open the individual pipes, gas is supplied from the supply source to the gas supply path 261. The supply amount is controlled by the flow rate controller. On the other hand, when the on-off valves close the individual pipes, the supply of gas from the supply source to the gas supply path 261 is stopped.

[0088] Although the embodiments of the film forming method and film forming apparatus according to the present disclosure have been described above, the present disclosure is not limited to the above embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. These naturally fall within the technical scope of the present disclosure.

[0089] This application claims priority based on Japanese Patent Application No. 2024-102635 filed with the Japan Patent Office on June 26, 2024, the entire contents of which are incorporated herein by reference.

[0090] W: Substrate W0: Laminated film W1: First film W2: Second film WA: Recess WB: Target film

Claims

1. A film formation method comprising: preparing a substrate having a laminated film including a first film containing boron and a second film formed of a material different from the first film, and a recess formed on the surface of the laminated film penetrating the first film and the second film; and selectively forming a target film inside the recess on a side surface of the second film relative to a side surface of the first film, wherein the target film contains a desired element X, and forming the target film comprises supplying to the substrate a source gas containing a compound of the element X and a halogen, and a reactive gas that reacts with an adsorbate of the source gas.

2. The film forming method according to claim 1, wherein the laminated film has a plurality of first repeating elements including the first film and the second film, and the side surface of the recess has a plurality of second repeating elements including the side surface of the first film and the side surface of the second film.

3. The film forming method according to claim 1, wherein the laminated film has the first film on the surface on which the recess is formed.

4. The film forming method according to claim 1, wherein the recess is a trench or a hole.

5. The film forming method according to claim 1, wherein the first film is a B film, a BN film, a BNC film, a BO film, a BC film, a BNOC film, a SiBN film, a SiBCN film, or a SiOBN film.

6. The film forming method according to claim 1, wherein the second film is a 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.

7. The second film is a Si film, a SiGe film, a GaN film, a ZTO film, an IGZO film, a graphene film, or a WS film. ２ Membrane, WSe ２ film, or MoS ２ The film forming method according to claim 1 , wherein the film is a film.

8. The film forming method according to claim 1, wherein the second film is a Cu film, a Co film, a Ru film, a Mo film, a W film, or a Ti film.

9. The film forming method according to claim 1, wherein the stacked film includes, in addition to the first film and the second film, a third film formed of a material different from the first film and the second film, and the recess is formed on the surface of the stacked film, penetrating the first film, the second film, and the third film.

10. The film forming method of claim 1, wherein forming the target film includes supplying an etching gas to the substrate after supplying the source gas and the reactive gas, which etches the target film formed on the side of the first film.

11. The film forming method according to claim 10, wherein forming the target film comprises repeating a cycle including supplying the source gas and the reactive gas and supplying the etching gas multiple times.

12. The film forming method according to claim 1, further comprising selectively etching a side surface of the second film relative to a side surface of the first film within the recess before forming the target film.

13. The film forming method according to claim 1, further comprising selectively etching a side surface of the first film relative to a side surface of the second film within the recess before forming the target film.

14. A film formation apparatus comprising: a processing vessel that accommodates the substrate; a holding unit that holds the substrate inside the processing vessel; a supply unit that supplies gas to the substrate held in the holding unit; and a control unit that controls the supply unit, wherein the control unit controls the supply unit so as to carry out the film formation method according to any one of claims 1 to 13.

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