Embedding method and substrate processing system

Abstract

To protect a film inside a recess from contamination to enhance a film characteristic.SOLUTION: A method for embedding a film containing a specified element into a recess formed on a substrate, includes the steps of: (a) in a first chamber, depositing a first film of the film containing the specified element; (b) in a second chamber, exposing the first film to gas containing halogen-containing gas to form a modification layer; (c) in the second chamber, depositing a protective film covering the modification layer; (d) in a third chamber, etching the protective film and sublimating the modification layer; and (e) in the third chamber, depositing a second film of the film containing the specified element.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an embedding method and a substrate processing system. [Background technology]

[0002] For example, Patent Documents 1 and 2 propose a method of filling recesses with a desired film by repeating a film formation process and an etching process a predetermined number of times. By combining film formation and etching, it is possible to suppress the occurrence of voids when filling recesses with a desired film. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-004542 [Patent Document 2] Patent Publication No. 2021-061348 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique that can protect a film in a recess from contamination and improve film properties. [Means for solving the problem]

[0005] According to one aspect of the present disclosure, there is provided a method for embedding a film containing a predetermined element into a recess formed in a substrate, the embedding method including: (a) depositing a first film containing the predetermined element in a first chamber; (b) exposing the first film to a gas containing a halogen-containing gas in a second chamber to form a modified layer; (c) depositing a protective film covering the modified layer in the second chamber; (d) etching the protective film and sublimating the modified layer in a third chamber; and (e) depositing a second film containing the predetermined element in the third chamber. [Effects of the Invention]

[0006] According to one aspect, the film in the recess can be protected from contamination, and the film properties can be improved. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram showing an example of a substrate processing system for performing a SiN film filling method according to an embodiment; [Figure 2] 1 is a diagram showing an example of a substrate processing system for performing a method for filling a SiO 2 film according to an embodiment; [Figure 3] 10 is a flowchart showing an example of an embedding method according to the embodiment. [Figure 4] FIG. 4 is an explanatory diagram of the embedding method of FIG. 3. [Figure 5] FIG. 2 is an explanatory diagram of a gas supply source and a control device of the substrate processing apparatus according to the embodiment. [Figure 6] FIG. 1 is a diagram showing an example of a substrate processing apparatus according to an embodiment. [Figure 7] 7 is a cross-sectional view taken along line AA in FIG. 6. [Figure 8] 3 is a flowchart showing an example of a method for forming a SiN film according to an embodiment. [Figure 9] 4 is a time chart showing an example of a method for forming a SiN film according to an embodiment. [Figure 10] 1 is a flowchart showing an example of forming an SiO 2 film according to an embodiment. [Figure 11] 4 is a time chart showing an example of a method for forming an SiO 2 film according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

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

[0009] In this specification, deviations in directions such as parallel, right angles, orthogonal, horizontal, vertical, up / down, left / right, etc. are permitted to the extent that they do not impair the effects of the embodiments. The shape of the corners is not limited to right angles and may be rounded like an arch. Parallel, right angles, orthogonal, horizontal, vertical, circular, and coincident may also include approximately parallel, approximately right angles, approximately orthogonal, approximately horizontal, approximately vertical, approximately circular, and approximately coincident.

[0010] [Substrate processing system] An example of a substrate processing system that executes the filling method of the embodiment will be described with reference to Figures 1 and 2. Figure 1 is a diagram showing an example of a substrate processing system that executes the filling method of a SiN film according to the embodiment. Figure 2 is a diagram showing an example of a substrate processing system that executes the filling method of a SiO2 film according to the embodiment.

[0011] The substrate processing system of the embodiment includes a plurality of batch-type substrate processing apparatuses that process a plurality of substrates W at once. In the example of FIGS. 1 and 2, the substrate processing system includes substrate processing apparatuses 10a and 10b. The substrate processing apparatuses 10a and 10b are separate substrate processing apparatuses. The substrate processing apparatuses 10a and 10b are also collectively referred to as substrate processing apparatuses 10.

[0012] The substrate processing apparatus 10a in FIGS. 1 and 2 has a first chamber 11, a plasma box 19, and gas nozzles 41A-41C and 41E, and performs film formation. The substrate processing apparatus 10b in FIGS. 1 and 2 has a second chamber 21, a plasma box 19, and gas nozzles 41A-41E, and performs modification and protective film formation. The substrate processing apparatuses 10a in FIGS. 1 and 2 have the same structure but supply different gases. The substrate processing apparatuses 10b in FIGS. 1 and 2 have the same structure and supply the same gas. When a SiN film is to be embedded in a recess formed in a substrate W, the SiN film is formed using the substrate processing apparatus 10a in FIG. 1. When a SiO2 film is to be embedded in a recess formed in a substrate W, the SiO2 film is formed using the substrate processing apparatus 10a in FIG. 2. The modification and protective film formation performed in the substrate processing apparatuses 10b in FIGS. 1 and 2 are the same process.

[0013] [Embedding method ST] Next, an example of a filling method ST according to an embodiment will be described with reference to FIGS. 1 to 4. FIG. 3 is a flowchart showing an example of the filling method ST according to the embodiment. FIG. 4 is an explanatory diagram of the filling method ST of FIG. 3. The filling method ST of FIG. 3 is controlled by a control device 90, which will be described later. When a SiN film is to be filled in a recess formed in a substrate W, the filling method ST of steps S1 to S6 shown in FIG. 3 is performed using the substrate processing system of FIG. 1. When a SiO2 film is to be filled in a recess formed in a substrate W, the filling method ST of steps S1 to S6 shown in FIG. 3 is performed using the substrate processing system of FIG. 2. First, the filling method ST of a SiN film using the substrate processing system of FIG. 1 will be described.

[0014] First, in step S1, a substrate W is prepared in the first chamber 11 of the substrate processing apparatus 10a. The prepared substrate W is a semiconductor substrate made of silicon or the like, and has a recessed portion thereon. Next, dichlorosilane (DCS: SiH2Cl2) gas, which is an example of a Si source gas, is supplied from the gas nozzle 41A, and ammonia (NH3) gas is supplied from the gas nozzle 41E, to form a SiN film in the recessed portion (first film formation).

[0015] FIG. 4(a) shows an example in which a SiN film 102 is formed on an undercoat film 101 in a recess H formed on a semiconductor substrate 100 such as silicon of a prepared substrate W. The SiN film 102 shown in FIG. 4(a) is an example of a first film (first film) containing a predetermined element. In the first film formation, a SiN film having an optimum thickness according to the shape of the recess H is formed. For example, the first film is formed so that the top of the recess H is not blocked.

[0016] The substrate W may have a fine three-dimensional structure on its surface. An example of the fine three-dimensional structure is a structure on which a fine pattern is formed. The fine pattern has, for example, a recess H as shown in FIG. 4(a). The recess H may be, for example, a trench or a hole. The base is not particularly limited.

[0017] Next, in step S2 of FIG. 3, the substrate W is temporarily removed from the first chamber 11 of the substrate processing apparatus 10a using a transfer device and transferred to the second chamber 21 of the substrate processing apparatus 10b. At this time, the substrate W is exposed to the atmosphere, and a native oxide film is formed on the SiN film. In the second chamber 21, the SiN film and the native oxide film formed by exposure to the atmosphere are exposed to a gas containing a halogen-containing gas to form a modified layer. The gas containing a halogen-containing gas may be a halogen-containing gas and a basic gas. The halogen-containing gas may be a gas containing fluorine or chlorine.

[0018] 1, hydrogen fluoride (HF) gas as an example of a halogen-containing gas is supplied from the gas nozzle 41B of the second chamber 21, and ammonia (NH3) gas as an example of a basic gas is supplied from the gas nozzle 41C. The HF gas and NH3 gas are used to convert the surface layer of the SiN film into a reaction product of ammonium silicofluoride (AFS: (NH4)2SiF6). To be modified (transformed) into The AFS layer (modified layer) is an etching intermediate. This 4(b), the surface layer of the SiN film 102 is modified to form an AFS modified layer 103. Here, the AFS modified layer 103 is formed thicker on the upper side of the recess H and thinner on the bottom side. In other words, the SiN film formed on the upper side of the recess is etched more than the SiN film formed on the bottom side.

[0019] If the temperature inside the second chamber 21 is controlled to a temperature at which the AFS is sublimated, the modified layer 103 will be sublimated and the SiN film will be etched. However, in the embedding method ST of the present disclosure, the second chamber 21 is controlled to a temperature at which the AFS is not sublimated. As a result, step S3 of FIG. 3 is performed in the second chamber 21 without sublimating the modified layer 103.

[0020] In step S3, a protective film covering the modified layer 103 is formed in the second chamber 21. In the example of FIG. 1, DIPAS, an example of a Si source gas, is supplied from the gas nozzle 41A of the second chamber 21, and O2 gas is supplied from the gas nozzle 41E. The O2 gas is converted into plasma in the plasma box 19. A protective film 104 made of SiO2 is formed on the modified layer 103 using the plasma of DIPAS and O2 gas. During the deposition of the SiO2 film, B2H6 gas, a catalytic gas, may be supplied from the gas nozzle 41D. During the formation of the protective film 104, the second chamber 21 is controlled to a temperature at which AFS does not sublimate, for example, below 100°C. As a result, as shown in FIG. 4(c), the SiN film 102 and the modified layer 103 can be protected by the protective film 104 made of SiO2 without sublimating the modified layer 103 made of AFS. 4(c) shows an example in which the recessed portion H is filled with the protective film 104 (the upper opening of the recessed portion H is closed), but this is not limitative. The upper portion of the recessed portion H does not have to be closed by the protective film 104.

[0021] Next, in step S4 of FIG. 3, the substrate W is moved from the second chamber 21 of the substrate processing apparatus 10b to a third chamber of the substrate processing apparatus. The third chamber may be the same as the first chamber 11 or a different chamber. In the following description, the third chamber will be described as the same chamber as the first chamber 11. During the movement of the chamber, the substrate W is exposed to the atmosphere. However, the modified layer 103 on the substrate W is covered by the protective film 104 of an SiO2 film. This protects the SiN film 102 and the modified layer 103 from oxidation and contamination by organic matter even if the substrate W is exposed to the atmosphere during transportation.

[0022] In step S4, the SiO2 protective film 104 is etched with a halogen-containing gas in the first chamber 11. When etching the protective film 104, the temperature in the first chamber 11 is controlled to a temperature at which the AFS sublimes, for example, 100°C or higher. The difference between the temperature in the second chamber 21 in step S3 and the temperature in the first chamber 11 in step S4 may be 150°C or higher.

[0023] As described above, when the protective film 104 is etched in the first chamber 11, the modified layer 103 is sublimated by heat. In the example of FIG. 1, HF gas is supplied from the gas nozzle 41B of the first chamber 11, and F2 gas is supplied from the gas nozzle 41C to etch the SiO2 protective film 104. HF gas and F2 gas are examples of halogen-containing gases, and at least one of HF gas and F2 gas may be supplied. As a result, the SiO2 protective film 104 and the modified layer 103 are removed (etched), as shown in FIG. 4(d). As a result, the SiN film 102 is reduced in thickness by the amount modified, and the recess H opens in a V-shape. This allows the next film to be formed while avoiding voids.

[0024] 3, the next SiN film is formed in the first chamber 11 (second film formation). As a result, as shown in FIG. 4(e), a SiN film 105 is formed on the SiN film 102 of the substrate W. The SiN film 105 is an example of a second film (a film formed twice) containing a predetermined element. The gas species used to form the SiN film 105 may be the same as the gas species used to form the SiN film 102.

[0025] Next, in step S6 of Fig. 3, it is determined whether the deposition of the second SiN film has been repeated a set number of times. In the example of the embodiment shown in Figs. 4(a) to (e), the filling of the recesses H is completed by performing steps S1 to S5 once, but depending on the shape of the recesses H, step S5 (Fig. 4(e)) may be performed so that the upper part of the recesses H is not blocked, and the processes of steps S2 to S5 may be repeated. The set number of times of step S6 is determined in advance as the number of times that the recesses H can be filled while suppressing the occurrence of voids and seams. When the processes of steps S2 to S5 have been repeated a set number of times, the filling of the recesses H is completed, and this process ends.

[0026] When depositing a SiN film, if the top of the recess is deposited thicker than the bottom, depositing the film as is will block the opening at the top of the recess, creating a void inside the recess. In this case, if etching is performed between the first and second depositions of the SiN film, and the film formed on the top of the recess is removed more than the film formed on the bottom, the SiN film can be deposited in the recess without any voids when the second deposition is performed.

[0027] In this way, when a film containing a predetermined element, such as a silicon-containing film or a metal-containing film, is formed in a recess on a substrate W, the formation of the film and the etching are repeatedly performed, thereby making it possible to avoid the occurrence of voids and fill the desired film in the minute recess. In such a filling method, the film formation and the etching may be performed in separate chambers or may be performed consecutively in the same chamber.

[0028] When the processes are performed consecutively in the same chamber, atmospheric contamination of the substrate W can be avoided. However, in this case, if the temperature conditions for film formation and etching differ significantly, the time required for temperature control in the chamber increases, reducing productivity. Therefore, when considering the reduction in productivity, restrictions are imposed on the temperature conditions when filling is performed in the same chamber.

[0029] In the embedding method ST of the present disclosure, film formation and etching are performed in separate chambers, so even if the temperature difference between the film formation temperature and the etching temperature is large, the temperature conditions for film formation and etching can be freely set without constraints while maintaining productivity.

[0030] However, each time the substrate W is transported between chambers, the substrate W is exposed to the atmosphere. As a result, the film formed on the substrate W may be oxidized by oxygen in the atmosphere to form an oxide film, or organic matter in the atmosphere may adhere to the film and contaminate it. This deteriorates the properties of the formed film. Therefore, it is necessary to prevent the formation of an oxide film on the surface of the substrate W and contamination.

[0031] In contrast, according to the embedding method ST of the present disclosure, the modified layer 103 is covered with the protective film 104 before the substrate W is moved from the second chamber 21 to the first chamber 11. As a result, the protective film 104 on the surface of the substrate W can protect the modified layer 103 and the SiN film 102 from atmospheric contamination during transportation of the substrate W. As a result, it is possible to prevent the surfaces of the modified layer 103 and the SiN film 102 from being oxidized to form oxide films, and to prevent contamination by organic substances. Furthermore, although the AFS (modified layer 103) is a thermally sublimable substance, because it is coated with the protective film 104 of an SiO2 film, the substrate W can be transferred from the second chamber 21 to the first chamber 11 in a stable state without volatilizing during transportation.

[0032] After the substrate W is transferred to the first chamber 11, the protective film 104 and the modified layer 103 are removed in the first chamber 11, and then a new SiN film is formed on the surface of the uncontaminated SiN film in the same chamber. As a result, the recesses can be filled with high-quality SiN films that do not contain native oxide films or contaminants at the interfaces of the first SiN film and subsequent SiN films.

[0033] In the substrate system of FIG. 2, a SiO2 film is embedded in the recessed portion H of the substrate W. In this case, in step S1 of FIG. 3, a SiO2 film is formed in the substrate processing apparatus 10a (first film formation). As shown in FIG. 2, in the first chamber 11 of the substrate processing apparatus 10a, DIPAS, which is an example of a Si source gas, is supplied from gas nozzle 41A, and O2 gas is supplied from gas nozzle 41E, to form the SiO2 film in the recessed portion. During the formation of the SiO2 film, B2H6 gas, a catalytic gas, may be supplied from gas nozzle 41B. The processes performed in steps S2 and S3 of FIG. 3 are the same as those described above, and therefore will not be described here.

[0034] 3, the protective film 104 and the modified layer 103 formed in steps S2 and S3 are removed in the first chamber 11. Next, in step S5, an SiO2 film is formed on the uncontaminated SiO2 film in the same chamber (second film formation). By repeating the processes of steps S2 to S5 a set number of times, the recesses can be filled with high-quality SiO2 films that do not contain native oxide films or contaminants at the interfaces between the first and subsequent SiO2 films.

[0035] The methods for filling the SiN film and the SiO2 film have been described above. The formation of the SiN film and the SiO2 film in the recesses (steps S1 and S5) may be performed by atomic layer deposition (ALD), which alternately supplies a source gas and a reactive gas to form the film. Alternatively, the chemical vapor deposition (CVD), which simultaneously supplies a source gas and a reactive gas to form the film, may be performed. The formation of the SiO2 film as the protective film 104 (step S3) may also be performed by either the ALD method or the CVD method. The formation of the SiN film by the ALD method (see FIGS. 8 and 9) and the formation of the SiO2 film by the ALD method (see FIGS. 10 and 11) will be described later.

[0036] [Process conditions] The process conditions of the embedding method ST of the present disclosure will be described with reference to Fig. 5. Fig. 5 is an explanatory diagram of various gas supply sources and a control device 90 that supply various gases to the first chamber 11 or the second chamber 21 according to the embodiment.

[0037] The gas supply unit of the substrate processing apparatus 10a includes a source gas supply source 44a, a reactive gas supply source 45a, a catalytic gas supply source 47a, and an etching gas supply source 48. Each gas supply source is connected to the first chamber 11 and supplies various gases into the first chamber 11. The gas supply unit of the substrate processing apparatus 10b includes a source gas supply source 44b, a reactive gas supply source 45b, a modifying gas supply source 46, a catalytic gas supply source 47b, and an etching gas supply source 48. Each gas supply source is connected to the second chamber 21 and supplies various gases into the second chamber 21. Gas pipes connecting the first chamber 11 and each gas supply source and the second chamber 21 and each gas supply source are provided with gas flow control valves, and the flow rates of the gases are controlled by the control device 90.

[0038] [Film formation conditions (gas type): Steps S1 and S5 in Figure 3] First, the process conditions (gas species) for film formation in steps S1 and S5 in FIG. 3 will be described in order for (1) filling the recesses with a SiN film and (2) filling the recesses with a SiO 2 film.

[0039] (1) When filling a recess with SiN film The source gas supply source 44a is connected to a gas nozzle 41A in the first chamber 11 shown in FIG. 1 and supplies the source gas into the first chamber 11 from a plurality of gas holes 42A (see FIG. 6) described below. The source gas contains a predetermined element when forming a film containing the predetermined element. When the predetermined element is silicon, the source gas is a Si source gas containing silicon.

[0040] In this embodiment, the Si source gas supplied to the first chamber 11 is DCS gas, but the technology of the present disclosure is not limited to this. In addition to DCS gas, other Si source gases may be used, such as monochlorosilane (MCS:SiH3Cl) gas, trichlorosilane (TCS:SiHCl3) gas, silicon tetrachloride (STC:SiCl4) gas, hexachlorodisilane (HCDS:Si2Cl6) gas, or a gas containing any of these gases. By supplying these gases to the substrate W, a layer containing silicon (Si) (Si-containing layer) can be formed on the substrate W. A gas containing a halogen element (e.g., BCl3 gas) may also be supplied together with the Si source gas.

[0041] 1, and supplies a reactive gas (nitriding gas) from a plurality of gas holes 42E (see FIG. 6), which will be described later, into the plasma box 19. The reactive gas (nitriding gas) is converted into plasma in the plasma box 19 and supplied into the first chamber 11, where it nitrides the Si-containing layer.

[0042] In this embodiment, the reactive gas is NH3 gas, but the technology of the present disclosure is not limited to this. The reactive gas may be NH3 gas, hydrogen (H2) gas, hydrazine (NH4) gas, or a gas containing any of these gases. Furthermore, these gases may further contain doping gases such as boron (B) gas or oxygen (O2) gas.

[0043] The reactive gas may be, for example, NH gas, an organic hydrazine compound gas, an amine-based gas, NO gas, NO gas, NO gas, or a gas containing any of these gases. The organic hydrazine compound gas may be, for example, hydrazine (NH) gas, diazene (NH) gas, or monomethylhydrazine (MMH) gas. The amine-based gas may be, for example, monomethylamine gas.

[0044] (2) When filling the recess with SiO2 film The source gas supply source 44a is connected to a gas nozzle 41A in the first chamber 11 shown in FIG. 2 and supplies the source gas into the first chamber 11 from a plurality of gas holes 42A (see FIG. 6) described below. The source gas contains a predetermined element when forming a film containing the predetermined element. When the predetermined element is silicon, the source gas is a Si source gas containing silicon.

[0045] The Si source gas supplied to the first chamber 11 in this embodiment is diisopropylaminosilane (DIPAS) gas (see first chamber 11 in FIG. 2 ), but the technology of the present disclosure is not limited to this. The Si source gas may be an aminosilane-based gas, a chlorosilane-based gas, or a silanol gas. The aminosilane-based gas may be DIPAS gas, dimethylaminosilane (DMAS) gas, bisdimethylaminosilane (BDMAS) gas, trisdimethylaminosilane (3DMAS) gas, bistertiarybutylaminosilane (BTBAS) gas, diethylaminosilane (DEAS) gas, bisdiethylaminosilane (BDEAS) gas, or DPAS (dipropylaminosilane) gas, or a gas containing any of these gases.

[0046] Examples of the chlorosilane-based gas include hexachlorodisilane (HCDS: SiCl) gas, monochlorosilane (MCS: SiHCl) gas, trichlorosilane (TCS: SiHCl) gas, silicon tetrachloride (STC: SiCl), and gases containing any of these gases. Examples of the silanol-based gas include tris(tert-pentoxy)silanol gas, triethylsilanol gas, methylbis(tert-pentoxy)silanol gas, and tris(tert-butoxy)silanol gas. By supplying these gases to the substrate W, a Si-containing layer can be formed on the substrate W.

[0047] 2, and supplies a reactive gas (oxidizing gas) from a plurality of gas holes 42E (described later) into the plasma box 19. The reactive gas (oxidizing gas) is converted into plasma in the plasma box 19 and supplied into the first chamber 11, where it oxidizes the Si-containing layer.

[0048] Although the reactive gas used in this embodiment is O2 gas, the technology of the present disclosure is not limited to this. H2O gas, O2 gas, and / or ozone (O3) gas may be used as a reactive gas to react with an aminosilane-based gas (DIPAS, 3DMAS, BTBAS, BDEAS gas, etc.). H2O gas and pyridine (CH5N) may be supplied as a reactive gas to react with a chlorosilane-based gas (HCDS gas, etc.). H2O gas, O2 gas, and / or ozone (O3) gas may be used as a reactive gas to react with a silanol-based gas (tris(tert-pentoxy)silanol gas, etc.). These gases may further contain a doping gas such as a boron (B)-containing gas, an oxygen (O)-containing gas, a nitrogen (N)-containing gas, or a carbon (C)-containing gas. Furthermore, a catalyst gas such as trimethylaluminum (TMA) gas, triethylborane (TEB) gas, or diborane (B2H6) gas may be supplied from the catalyst gas supply source 47a. When a silanol-based gas is used as the source gas, the use of a catalyst gas allows a SiO2 film to be formed without using a reactive gas. In the first chamber 11 shown in FIG. 2, B2H6 gas, which is a catalyst gas, may be supplied during the formation of the SiO2 film. The catalyst gas supply source 47a is connected to a gas nozzle 41B in the first chamber 11 shown in FIG. 2, and supplies the catalyst gas into the first chamber 11 from a plurality of gas holes 42B (see FIG. 6), which will be described later. However, the catalyst gas need not be supplied.

[0049] [Modification conditions and protective film formation conditions (gas type): Steps S2 and S3 in Figure 3] Next, the process conditions (gas species) for the modification performed in step S2 and the protective film formation performed in step S3 in Fig. 3 will be described. A modifying gas supply source 46 shown in Fig. 5 is connected to gas nozzles 41B and 41C in the second chamber 21 shown in Figs. 1 and 2, and supplies a modifying gas into the second chamber 21 from a plurality of gas holes 42B and 42C (see Fig. 6), which will be described later. This modifies the SiN film or SiO2 film.

[0050] The modifying gases used in this embodiment are NH3 gas and HF gas (see second chamber 21 in FIGS. 1 and 2), but the technology of the present disclosure is not limited to this. In addition to NH3 gas and HF gas, F2 gas and NF3 gas may also be used as the modifying gas. When NF3 gas is used, the NF3 gas may be converted into plasma in plasma box 19 and supplied into second chamber 21.

[0051] During the formation of the protective film, the source gas supply source 44b supplies a Si source gas into the second chamber 21. In this embodiment, the Si source gas supplied to the second chamber 21 is diisopropylaminosilane (DIPAS) gas (see the second chamber 21 in FIGS. 1 and 2), but the technology of the present disclosure is not limited thereto. The Si source gas may be the same as the Si source gas supplied from the source gas supply source 44a.

[0052] The reactive gas supply source 45b supplies a reactive gas (oxidizing gas) into the second chamber 21 to oxidize the Si-containing layer. In this embodiment, the reactive gas (oxidizing gas) is O gas, but the technology of the present disclosure is not limited thereto. The reactive gas may be the same gas as the oxidizing gas supplied from the reactive gas supply source 45a.

[0053] [Etching conditions and film formation conditions (gas type): Steps S4 and S5 in Figure 3] Next, the process conditions (gas species) for removing the protective film in step S4 and forming the film in step S5 in Fig. 3 will be described. An etching gas supply source 48 shown in Fig. 5 is connected to a gas nozzle 41C in the first chamber 11 in Figs. 1 and 2 and a gas nozzle 41B in the first chamber 11 in Figs. 1 and 2, and supplies an etching gas into the first chamber 11 from a plurality of gas holes 42B and 42C (see Fig. 6), which will be described later. This etches the protective film.

[0054] The gas used to etch the protective film is a halogen-containing gas. The etching gas used in this embodiment is F2 gas and HF gas (see the first chamber 11 in FIGS. 1 and 2), but the technology of the present disclosure is not limited thereto. Alternatively, a fluorine-containing gas such as F2 gas, HF gas, ClF3 gas, NF3 gas, or a combination thereof may be used as the etching gas.

[0055] The etching conditions are preferably such that the SiO2 film serving as the protective film is easily removed and the SiN film or SiO2 film to be filled is not easily removed, but are not limited to these. For example, the SiO2 film serving as the protective film formed in the second chamber 21 is formed at a low temperature and has poor film quality, so it is more easily removed than the SiN film or SiO2 film to be filled.

[0056] When the protective film is etched, the modified layer of the AFS is thermally sublimated. In this way, the protective film and the AFS (modified layer), which is an etching intermediate, are removed. After the protective film and the modified layer are removed, a second film of the SiN film or SiO2 film formed in step S1 of FIG. 3 is formed. The film formation conditions may be the same as or different from the conditions described in step S1 of FIG. 3.

[0057] In the first chamber 11, an example has been described in which NH3 gas plasma is generated in the plasma box 19 during SiN film formation. Also, in the second chamber 21, an example has been described in which O2 gas plasma is generated in the plasma box 19 during SiO2 protective film formation. However, the plasma box 19 may not be necessary. The plasma box 19 may not be necessary in the substrate processing apparatus 10 when nitriding the Si-containing film by heat treatment, when nitriding the Si-containing film using only thermal energy by using a hydrazine-based gas instead of ammonia, or when O3 gas is used to form the SiO2 film.

[0058] Furthermore, a purge gas supply source (not shown) may be provided. By supplying a purge gas into the first chamber 11 and the second chamber, gas remaining inside the first chamber 11 and the second chamber is removed. As the purge gas, for example, an inert gas is used. As the inert gas, a rare gas such as Ar gas or N2 gas is used.

[0059] The F2 gas and HF gas supplied to the first chamber 11 in FIG. 1, the F2 gas and HF gas supplied to the first chamber 11 in FIG. 2, and the HF gas supplied to the second chamber 21 in FIGS. 1 and 2 can also be used as cleaning gases for cleaning each chamber.

[0060] [Process conditions (temperature): Steps S1 to S5 in Figure 3] Next, the process conditions (temperatures) for steps S1 to S5 in Fig. 3 will be described. In the filling method ST of the present disclosure, the modification and protective film formation (steps S2 and S3) performed in the second chamber 21 are performed at a lower temperature range than the film formation (steps S1 and S5) and etching (step S4) performed in the first chamber 11. In the following, a SiN film is used as an example of the filling target, but the same temperature control is performed even when a SiO2 film or other film is used.

[0061] In step S1, the temperature inside the first chamber 11 is controlled to 100°C or higher (preferably 250 to 700°C), and the substrate W is heated to 100°C or higher to form a SiN film. In step S2, the temperature inside the second chamber 21 is controlled to less than 100°C, and HF gas and NH3 gas are supplied to the surface of the SiN film to form an AFS (modified layer). At this time, part of the SiN film is modified and incorporated into the modified layer.

[0062] In step S3, a protective film of SiO2 film is formed while the temperature inside the second chamber 21 is controlled to less than 100° C. For example, when forming an SiO2 film using a Si source gas of DIPAS and O2 radicals in an O2 plasma, the reaction can be carried out at room temperature.

[0063] The same temperature range is used to form a protective film on the modified SiO2 film, but it does not have to be the same temperature as long as the AFS does not sublime. Therefore, the temperature in the second chamber 21 is in the range of 25°C to less than 100°C (for example, 70°C), at which the AFS does not sublime. To enable film formation in this temperature range, a catalyst gas is added as needed, so that the SiO2 film can be formed while the temperature in the second chamber 21 is controlled to less than 100°C.

[0064] In step S4, the temperature inside the first chamber 11 is controlled to 100°C or higher (preferably 250 to 700°C), and the substrate W is heated to 100°C or higher. This causes the etching gas to etch the SiO2 protective film, while simultaneously volatilizing and removing the modified layer of the AFS. After step S4, in step S5, the temperature inside the first chamber 11 is continued to be controlled to 100°C or higher, and the substrate W is heated to 100°C or higher to form a SiN film.

[0065] The temperature of the first chamber 11 is maintained in the temperature range of 250 to 700°C (for example, 550°C). Therefore, if the modified layer of the AFS is not coated with a protective film, thermal sublimation of the AFS occurs when the substrate W is transferred to the first chamber 11, and the vaporized AFS diffuses not only in the first chamber 11 but also within the transfer module, causing contamination.

[0066] Furthermore, in order to sublimate the modified layer of the AFS in the second chamber 21, it is necessary to raise the temperature in the second chamber 21 to the sublimation temperature of the AFS. To eliminate such time loss, in the embedding method ST of the present disclosure, the sublimation of the AFS is performed in the first chamber 11.

[0067] That is, in the embedding method ST of the present disclosure, after forming the AFS modified layer in the second chamber 21 whose temperature is controlled to less than 100° C., the AFS modified layer is capped with a protective film of SiO2 film in the same chamber by low-temperature film formation at less than 100° C., and then transferred to the first chamber 11. This makes it possible to prevent the AFS modified layer from sublimating even if heat is applied during transport of the substrate W to the first chamber 11.

[0068] After being transferred to the first chamber 11, the SiO2 protective film capping the modified layer of the AFS is removed before the next SiN film is formed. This SiO2 film is removed at a processing temperature close to the temperature range for forming the SiN film. At the same time as the SiO2 protective film is removed, the modified layer of the AFS is sublimated by heat.

[0069] This allows for the stacking of SiN films without generating oxide films or contamination at the interface between the first and second depositions when film formation and etching are performed in separate chambers. Furthermore, when performing the filling method consecutively in the same chamber, a wide range of temperature changes is required at each step. In contrast, the filling method ST of the present disclosure uses separate chambers for each step of the filling method, eliminating the need for time-consuming temperature control and enabling the formation of films with high-quality film properties in a short time.

[0070] 3, the substrate processing apparatus 10 includes a control device 90 that controls the substrate processing apparatus 10. The control device 90 is configured, for example, by a computer, and includes a CPU (Central Processing Unit) 91 and a memory 92. The memory 92 stores programs that control various processes executed in the substrate processing apparatus 10. The control device 90 controls the operation of the substrate processing apparatus 10 by causing the CPU 91 to execute the programs stored in the memory 92. The control device 90 also includes an input interface 93 and an output interface 94. The control device 90 receives signals from the outside via the input interface 93 and transmits signals to the outside via the output interface 94.

[0071] Such a program may be stored in a computer-readable medium and installed from that medium into the memory 92 of the control device 90. Examples of computer-readable media include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnetic optical disk (MO), and a memory card. The program may also be downloaded from a server via the Internet and installed into the memory 92 of the control device 90.

[0072] (Membrane type) The type of film to be filled into the recess is not limited to a SiN film or a SiO2 film, but may be a film containing a predetermined element. The predetermined element is either Si, germanium (Ge), or a metal. When the predetermined element is Si, the film containing the predetermined element may be a silicon film, a silicon-containing oxide film, or a silicon-containing nitride film. For example, it may be a Si film, a SiN film, a SiON film, a SiCN film, a SiOCN film, a SiBN film, a SiBCN film, or a SiFN film.

[0073] When the predetermined element is a metal, the metal is either titanium (Ti), aluminum (Al), or tungsten (W). In this case, the film containing the predetermined element can be a metal film of Ti, Al, or W, or an oxide or nitride film of such a metal.

[0074] The protective film is not limited to an SiO2 film, but may be an oxide film of a film containing a predetermined element.

[0075] [Substrate processing equipment] Next, a substrate processing apparatus 10 capable of performing the embedding method ST according to the embodiment will be described with reference to Fig. 6 and Fig. 7. Fig. 6 is a diagram showing an example of the substrate processing apparatus 10 according to the embodiment, and Fig. 7 is a cross-sectional view taken along line AA in Fig. 6.

[0076] When the substrate processing apparatus 10 is the substrate processing apparatus 10a, the substrate processing apparatus 10a includes a first chamber 11, a gas supply device 40, an exhaust device 50, a heating device 60, and a control device 90. The gas supply device 40 of the substrate processing apparatus 10a includes four gas nozzles 41A to 41C, 41E. The gas nozzles 41A to 41C, 41E include a plurality of gas holes 42A to 42C, 42E.

[0077] When the substrate processing apparatus 10 is the substrate processing apparatus 10b, the substrate processing apparatus 10b includes a second chamber 21, a gas supply device 40, an exhaust device 50, a heating device 60, and a control device 90. The gas supply device 40 of the substrate processing apparatus 10b includes five gas nozzles 41A to 41E. The gas nozzles 41A to 41E each include a plurality of gas holes 42A to 42E.

[0078] 7 shows the configuration of the substrate processing apparatus 10a having four gas nozzles 41A to 41C, 41E. Since the other configurations are the same between the substrate processing apparatus 10a and the substrate processing apparatus 10b, the configuration of the substrate processing apparatus 10a will be described below as the substrate processing apparatus 10.

[0079] A ceiling plate 12 is provided near the upper end of the first chamber 11, and the area below the ceiling plate 12 is sealed. The first chamber 11 and ceiling plate 12 are formed of, for example, quartz, and house a substrate holder 30. A cylindrical metal manifold 14 is connected to the opening at the lower end of the first chamber 11 via a sealing member 16 such as an O-ring. The manifold 14 supports the lower end of the first chamber 11, and the substrate holder 30 is inserted into the first chamber 11 from below the manifold 14.

[0080] The substrate holder 30 holds a plurality of substrates W (e.g., 25 to 150 substrates W), e.g., semiconductor wafers, in a shelf-like manner. The substrate holder 30 is made of, for example, quartz. The substrate holder 30 supports the plurality of substrates W using three supports. The substrate holder 30 is placed on a table 27 via a heat-retaining cylinder 28 made of quartz. The heat-retaining cylinder 28 suppresses a decrease in temperature inside the first chamber 11 due to heat radiation from the lower side of the first chamber 11. The table 27 is supported on a rotating shaft 24. The rotating shaft 24 passes through a metal (e.g., stainless steel) cover 20 that opens and closes an opening at the lower end of the manifold 14.

[0081] A magnetic fluid seal 23 is provided at the penetration portion of the rotating shaft 24. The magnetic fluid seal 23 airtightly seals the rotating shaft 24 and rotatably supports the rotating shaft 24. A seal member 15 such as an O-ring is provided between the peripheral portion of the lid 20 and the lower end of the manifold 14 to maintain airtightness inside the first chamber 11. The rotating shaft 24 is attached to the tip of an arm 26 supported by an elevation mechanism 25 such as a boat elevator. As the arm 26 moves up and down, the substrate holder 30 and the lid 20 move up and down together and are inserted into and removed from the first chamber 11.

[0082] Plasma box 19 is provided on a part of the sidewall of first chamber 11. In the example of FIG. 7, gas nozzles 41A to 41C are disposed in first chamber 11, and gas nozzle 41E is disposed in plasma box 19.

[0083] The gas nozzles 41A to 41C, 41E are made of, for example, quartz. The gas nozzles 41A to 41C penetrate the sidewall of the manifold 14 inward, bend upward, and extend vertically. The base ends of the gas nozzles 41A to 41C are located outside the first chamber 11 and connected to one of the gas supply sources shown in FIG. 5. The vertical portions of the gas nozzles 41A to 41C are located inside the first chamber 11. The vertical portions of the gas nozzles 41A to 41C have multiple gas holes 42A to 42C formed at predetermined intervals along a vertical length corresponding to the substrate support range of the substrate holder 30. The gas nozzles 41A to 41C horizontally eject source gases, an example of which is shown in FIG. 1 or 2, from the gas supply sources via gas piping into the first chamber 11 through the multiple gas holes 42A to 42C.

[0084] The gas nozzle 41E penetrates the side wall of the manifold 14 inward, bends upward, and extends vertically. The base end of the gas nozzle 41E is located outside the first chamber 11 and is connected to a gas supply source. The vertical portion of the gas nozzle 41E is located within the plasma box 19. The vertical portion of the gas nozzle 41E has a plurality of gas holes 42E formed at predetermined intervals along a length in the vertical direction that corresponds to the substrate support range of the substrate holder 30. The gas nozzle 41E horizontally discharges gas, an example of which is shown in FIG. 1 or 2 , introduced from the gas supply source via a gas piping from the plurality of gas holes 42E into the plasma box 19.

[0085] An opening 17 is formed in a portion of the periphery of the first chamber 11. A plasma box 19 is formed on the side surface of the first chamber 11 so as to surround the opening 17. As shown in FIG. 7 , a pair of electrodes 81, 82 are arranged to sandwich the plasma box 19. The electrodes 81, 82 are a pair of parallel electrodes installed facing each other on the outside of the plasma box 19. The electrodes 81, 82 are connected to an RF power supply 55, and a high-frequency voltage is applied from the RF power supply 55 to the electrodes 81, 82.

[0086] 6, exhaust device 50 includes a vacuum pump and evacuates the inside of first chamber 11. Exhaust port 18 is formed in first chamber 11, and gas inside first chamber 11 passes through exhaust port 18 and is then exhausted from exhaust pipe 43.

[0087] The heating device 60 is disposed outside the first chamber 11 and heats the interior of the first chamber 11. For example, the heating device 60 is formed in a cylindrical shape so as to surround the first chamber 11. The heating device 60 is formed, for example, by an electric heater. The heating device 60 heats the interior of the first chamber 11, thereby improving the processing capacity of the gas supplied into the first chamber 11.

[0088] [SiN film deposition method] An example of a method for forming a SiN film performed by the substrate processing apparatus 10 will be described with reference to FIGS. 8 and 9. FIG. 8 is a flowchart showing an example of the method for forming a SiN film according to an embodiment. FIG. 9 is a time chart showing an example of the method for forming a SiN film according to an embodiment. Hereinafter, an example will be described in which a SiN film is formed by the ALD method using DCS gas as the Si source gas, NH gas as the reactive gas, and Ar gas as the purge gas.

[0089] First, the temperature inside the first chamber 11 is adjusted to 100°C or higher, and the substrate holder 30 carrying a plurality of substrates W is carried into the first chamber 11. Next, the inside of the first chamber 11 is evacuated by the exhaust device 50, while the inside of the first chamber 11 is adjusted to a predetermined pressure.

[0090] In step S21 of Fig. 8, DCS gas is supplied into the first chamber 11 from time t1 to time t2 shown in Fig. 9. As a result, the silicon-containing gas is adsorbed onto the surface of the substrate W, forming a Si-containing layer.

[0091] Next, in step S22, the inside of first chamber 11 is evacuated by exhaust device 50 while replacing the atmosphere inside first chamber 11 with Ar gas. As shown in Fig. 9, the purge gas has been continuously supplied since before time t1. As a result, the silicon-containing gas remaining in first chamber 11 is exhausted, and the atmosphere inside first chamber 11 is replaced with Ar gas.

[0092] Next, in step S23, NH3 gas is supplied to the plasma box 19 from time t3 to time t4 shown in Fig. 9, and a high-frequency voltage is applied from the RF power supply 55 to the electrodes 81 and 82 from time t3 to time t4 shown in Fig. 9. As a result, plasma of the NH3 gas is generated in the plasma box 19, and reactive species such as radicals in the plasma are supplied into the first chamber 11.

[0093] Next, in step S24, the inside of the first chamber 11 is evacuated by the exhaust device 50 while the inside of the first chamber 11 is replaced with Ar gas. As a result, the NH gas remaining in the first chamber 11 is discharged, and the atmosphere in the first chamber 11 is replaced with Ar gas.

[0094] Next, steps S21 to S24 are repeated until it is determined in step S25 that the set number of repetitions have been reached, thereby depositing a SiN film of a predetermined thickness. Subsequently, the substrate holder 30 carrying the plurality of substrates W on which the SiN film has been deposited is unloaded from the first chamber 11, and the process ends.

[0095] In the above embodiment, the SiN film is formed by the plasma ALD method, but the present invention is not limited to this. For example, nitridation may be performed by heat treatment. For example, the SiN film may be formed by chemical vapor deposition (CVD). For example, a SiO2 film, a metal nitride film, a metal oxide film, or the like may be formed instead of the SiN film.

[0096] [SiO2 film deposition method] An example of a method for forming an SiO2 film performed by the substrate processing apparatus 10 will be described with reference to FIGS. 10 and 11. FIG. 10 is a flowchart illustrating an example of the method for forming an SiO2 film according to an embodiment. FIG. 11 is a time chart illustrating an example of the method for forming an SiO2 film according to an embodiment. The SiO2 film referred to here may be a film that is filled into a recess by film formation performed in the first chamber 11, or may be an SiO2 film that serves as a protective film performed in the second chamber 21. In the following, an SiO2 film is formed by the ALD method using DIPAS gas as a Si source gas, O2 gas as a reactive gas, and Ar gas as a purge gas.

[0097] When forming an SiO2 film to be embedded in the recesses, the temperature inside the first chamber 11 is adjusted to 100°C or higher, and the substrate holder 30 carrying the plurality of substrates W is carried into the first chamber 11. Next, the inside of the first chamber 11 is evacuated by the exhaust device 50, while the inside of the first chamber 11 is adjusted to a predetermined pressure.

[0098] On the other hand, when forming an SiO2 film as a protective film, the temperature inside the second chamber 21 is adjusted to less than 100°C, and the substrate holder 30 carrying the plurality of substrates W is carried into the second chamber 21. Subsequently, the inside of the second chamber 21 is evacuated by the exhaust device 50, while the inside of the second chamber 21 is adjusted to a predetermined pressure.

[0099] 10, DIPAS gas is supplied into the first chamber 11 from time t11 to time t12 shown in Fig. 11. As a result, the silicon-containing gas is adsorbed onto the surface of the substrate W, forming a Si-containing layer.

[0100] Next, in step S32, the atmosphere in the chamber is replaced with Ar gas while being evacuated by the exhaust device 50. As shown in Fig. 11, the purge gas has been continuously supplied since before time t11. As a result, the silicon-containing gas remaining in the chamber is exhausted and the atmosphere in the chamber is replaced with Ar gas.

[0101] Next, in step S33, O2 gas is supplied to the plasma box 19 from time t13 to time t14 shown in Fig. 11, and a high-frequency voltage is applied from the RF power supply 55 to the electrodes 81 and 82 from time t13 to time t14 shown in Fig. 11. As a result, plasma of the O2 gas is generated in the plasma box 19, and reactive species such as radicals in the plasma are supplied into the chamber.

[0102] Next, in step S34, the atmosphere inside the chamber is replaced with Ar gas while being evacuated by the exhaust device 50. As a result, the O2 gas remaining in the chamber is discharged, and the atmosphere inside the first chamber 11 is replaced with Ar gas.

[0103] Next, steps S31 to S34 are repeated a predetermined number of times until it is determined in step S35 that the set number of repetitions have been reached, thereby depositing an SiO film of a predetermined thickness. Subsequently, the substrate holder 30 carrying the plurality of substrates W on which the SiO film has been deposited is unloaded from the chamber, and the process is completed.

[0104] As described above, according to the filling method and substrate processing system of this embodiment, it is possible to protect a film in a recess formed in a substrate moving between chambers from oxidation and contamination, thereby improving film properties.

[0105] The filling method and the substrate processing system according to the presently disclosed embodiments should be considered to be illustrative in all respects and not restrictive. The embodiments can be modified and improved in various ways without departing from the spirit and scope of the appended claims. The features described in the above embodiments can be configured in other ways as long as they are not inconsistent, and can be combined as long as they are not inconsistent. [Explanation of symbols]

[0106] 10. Substrate processing equipment 11 First Chamber 21 Second Chamber 40 Gas supply unit 50 Exhaust section 60 Heating section 90 Control device 102 SiN film 103 Modified layer 104 Protective film 41A~41E Gas Nozzle

Claims

1. A method for filling a recess formed in a substrate with a film containing a predetermined element, comprising the steps of: (a) depositing a first film containing the predetermined element in a first chamber; (b) exposing the first film to a gas containing a halogen-containing gas in a second chamber to form a modified layer; (c) forming a protective film covering the modified layer in the second chamber; (d) etching the protective film and sublimating the modified layer in a third chamber; (e) depositing a second film containing the predetermined element in the third chamber; 10. A method of embedding a substrate, comprising:

2. The predetermined element is any one of Si, Ge, and a metal. The embedding method according to claim 1 .

3. The metal is either Ti, Al or W; The embedding method according to claim 2 .

4. In the step (a), the first film is formed so as not to close an upper portion of the recess. The embedding method according to any one of claims 1 to 3.

5. (f) exposing the second film to a gas containing a halogen-containing gas in the second chamber to form a modified layer; (f), (c), (d), and (e) are repeated in this order to stack a plurality of films containing the predetermined element. The embedding method according to any one of claims 1 to 4.

6. In the step (b), the halogen-containing gas and a basic gas are supplied. The embedding method according to claim 5.

7. The basic gas is ammonia gas. The embedding method according to claim 6.

8. In the step (d), a halogen-containing gas is supplied as an etching gas for the protective film. The embedding method according to any one of claims 1 to 7.

9. The halogen-containing gas is a gas containing F. The embedding method according to any one of claims 1 to 8.

10. The first chamber and the third chamber are the same chamber. The embedding method according to any one of claims 1 to 9.

11. the first chamber and the second chamber are different chambers, The substrate is exposed to the atmosphere when moving between the first chamber and the second chamber. The embedding method according to any one of claims 1 to 10.

12. In the step (c), the temperature inside the second chamber is controlled to a temperature at which the modified layer does not sublimate; In the step (d), the temperature inside the third chamber is controlled to a temperature at which the modified layer sublimes. The embedding method according to any one of claims 1 to 11.

13. In the step (c), the temperature inside the second chamber is controlled to be less than 100°C; In the step (d), the temperature inside the third chamber is controlled to 100° C. or higher. The embedding method according to claim 12.

14. a difference between the temperature in the second chamber in (c) and the temperature in the third chamber in (d) is 150°C or more; The embedding method according to claim 13.

15. the protective film is an oxide film containing the predetermined element; The embedding method according to any one of claims 1 to 14.

16. 1. A substrate processing system having a plurality of chambers and a controller, The control device A substrate processing system that controls the filling method according to any one of claims 1 to 15.

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