Film formation method and film formation device

Abstract

A film formation method according to one embodiment of the present disclosure comprises: (a) a step for preparing a substrate having a first region in which a nitride film is exposed and a second region in which an oxide film is exposed; (b) a step for maintaining a temperature of the substrate at a first temperature of at least 600°C and supplying a fluorine-containing gas to the substrate such that fluorine is adsorbed on the second region; and (c) a step for maintaining the temperature of the substrate at a second temperature of at least 600°C and supplying a film formation gas to the substrate to form a new nitride film on the first region.

Description

Film deposition method and film deposition apparatus

[0001] This disclosure relates to a film deposition method and a film deposition apparatus.

[0002] A technique for selectively forming a semiconductor film in areas where the nitride film of a substrate is exposed is known (see, for example, Patent Document 1).

[0003] Japanese Patent Publication No. 2021-57439

[0004] This disclosure provides a technique for depositing a nitride film with good film quality in an exposed region of a substrate.

[0005] A film-forming method according to one aspect of the present disclosure includes the steps of: (a) preparing a substrate having a first region where a nitride film is exposed and a second region where an oxide film is exposed; (b) maintaining the temperature of the substrate at a first temperature of 600°C or higher and supplying a fluorine-containing gas to the substrate to adsorb fluorine onto the second region; and (c) maintaining the temperature of the substrate at a second temperature of 600°C or higher and supplying a film-forming gas to the substrate to form a new nitride film on the first region.

[0006] According to this disclosure, a nitride film with good film quality can be formed in the region of the substrate where the nitride film is exposed.

[0007] This is a flowchart illustrating an example of a film deposition method according to the first embodiment. This is a schematic cross-sectional view showing an example of a prepared substrate. This is a schematic cross-sectional view showing an example of a substrate after the native oxide film has been removed. This is a schematic cross-sectional view showing an example of a substrate after fluorine has been adsorbed onto the second region. This is a schematic cross-sectional view showing an example of a substrate after a nitride film has been deposited on the first region. This is a graph showing an example of the relationship between the number of repetitions and the thickness of the nitride film on the first region and the thickness of the nitride film on the second region. This is a flowchart illustrating an example of a film deposition method according to the second embodiment. This is a schematic vertical cross-sectional view showing a film deposition apparatus. This is a schematic horizontal cross-sectional view showing a film deposition apparatus.

[0008] Hereinafter, exemplary embodiments of the present disclosure, not limited to those described herein, will be described with reference to the attached drawings. In all attached drawings, the same or corresponding members or components are denoted by the same or corresponding reference numerals, and redundant descriptions are omitted.

[0009] [Film Formation Method of the First Embodiment] An example of a film formation method according to the first embodiment will be described with reference to Figures 1 and 2. Figure 1 is a flowchart showing an example of a film formation method according to the first embodiment. Figure 2 is a cross-sectional view showing an example of a film formation method according to the first embodiment.

[0010] The film deposition method according to the first embodiment includes steps S11 to S15 shown in Figure 1. Figure 2A is a schematic cross-sectional view showing an example of a prepared substrate 100. As shown in Figure 2A, in step S11, a substrate 100 is prepared having a first region 101 where a nitride film is exposed and a second region 102 where an oxide film is exposed. A native oxide film 105 may be present on the first region 101 and the second region 102. Step S11 may also include, for example, loading the substrate 100 into a processing container.

[0011] The substrate 100 may have further regions different from the first region 101 and the second region 102. That is, the substrate 100 may have further regions where a film different from the nitride film and the oxide film is exposed. In the example shown in Figure 2A, the substrate 100 has one first region 101 and one second region 102. However, the number of first regions 101 and second regions 102 in the substrate 100 may be multiple. When the substrate 100 has multiple first regions 101 and multiple second regions 102, the multiple first regions 101 and the multiple second regions 102 may be arranged alternately in the in-plane direction, for example.

[0012] The nitride film in the first region 101 is, for example, a silicon nitride film. A silicon nitride film contains silicon (Si) and nitrogen (N). The nitride film in the first region 101 may also be a different type of nitride film than the silicon nitride film. Examples of different types of nitride films include germanium nitride films and metal nitride films. A germanium nitride film is a film containing germanium (Ge) and nitrogen (N). A metal nitride film is a film containing metal elements such as hafnium (Hf), tin (Sn), titanium (Ti), zirconium (Zr), tungsten (W), and aluminum (Al), along with nitrogen (N).

[0013] The oxide film in the second region 102 is, for example, a silicon oxide film. A silicon oxide film contains silicon (Si) and oxygen (O). The oxide film in the second region 102 may also be a different type of oxide film than the silicon oxide film. Examples of different types of oxide films include germanium oxide films and metal oxide films. A germanium oxide film is a film containing germanium (Ge) and oxygen (O). A metal oxide film is a film containing metal elements such as hafnium (Hf), tin (Sn), titanium (Ti), zirconium (Zr), tungsten (W), and aluminum (Al), along with oxygen (O).

[0014] Step S12 is performed after step S11. Figure 2B is a schematic cross-sectional view showing an example of the substrate 100 after the native oxide film 105 has been removed. Step S12 includes supplying the substrate 100 with a fluorine-containing gas and a basic gas to remove the native oxide film 105, at least on the first region 101, as shown in Figure 2B. That is, step S12 is performed as a COR (Chemical Oxide Removal) treatment. In the example shown in Figure 2B, step S12 removes the native oxide film 105 on the first region 101 and the second region 102. Note that if the native oxide film 105 is not present on at least the first region 101, step S12 can be omitted.

[0015] In step S12, a fluorine-containing gas and a basic gas are supplied to the substrate 100 as processing gases to cause a chemical reaction between the native oxide film 105 and the processing gases, and the reaction products obtained as a result of the chemical reaction are removed. The fluorine-containing gas includes, for example, hydrogen fluoride (HF). The fluorine-containing gas also contains fluorine molecules (F ２ ), chlorine trifluoride (ClF ３ ), boron trifluoride (BF ３ ), nitrogen trifluoride (NF ３ ), tetrafluorosilane (SiF ４ ), hexafluorodisilane (Si ２ F ６ ), fluoromethane (CH ３It may also be a gas containing a fluorine compound different from fluorine molecules or hydrogen fluoride, such as a fluorocarbon compound such as F). The basic gas includes, for example, ammonia (NH ３ ). The basic gas may also be a gas containing a basic compound different from ammonia, such as trimethylamine, triethylamine, hydrazine, a hydrazine derivative, etc. When the fluorine-containing gas contains hydrogen fluoride and the basic gas contains ammonia, mainly ammonium silicofluoride [(NH ４ ), ２ SiF ６ , water (H ２ O), and other reaction products are generated.

[0016] In step S12, after the COR treatment, a PHT (Post Heat Treatment) treatment may be performed. The PHT treatment is a treatment that heats reaction products such as ammonium silicofluoride generated by the COR treatment and sublimates the reaction products. By performing the PHT treatment, the natural oxide film 105 can be more reliably removed. In this embodiment, the substrate temperature is raised to perform step S13 described later. This temperature raising treatment may be used as the PHT treatment.

[0017] Here, fluorine (F) has the property of adsorbing more readily with oxygen contained in the oxide film than with nitrogen contained in the nitride film. In this embodiment, the oxide film is exposed in the second region 102. Therefore, when the substrate 100 is exposed to fluorine-containing gas during the COR treatment, as shown in Figure 2B, more fluorine 103a is adsorbed on the second region 102 than on the first region 101. The fluorine 103a adsorbed on the second region 102 inhibits the formation of a new nitride film 107 in step S14, which will be described later. As a result, the fluorine 103a adsorbed on the second region 102 inhibits the formation of a nitride film on the second region 102, while a new nitride film 107 can be formed on the first region 101. Note that inhibiting the formation of a nitride film on the second region 102 and forming a new nitride film 107 on the first region 101 may be referred to as "selectively forming a new nitride film 107 on the first region 101" below. Furthermore, when a new nitride film 107 is selectively formed on the first region 101, a small amount of nitride film may also be formed on the second region 102. Note that when a small amount of nitride film is formed on the second region 102, it means that the thickness of the nitride film formed on the second region 102 is 1 / 10 or less of the thickness of the new nitride film 107 formed on the first region 101. The new nitride film 107 may hereafter be referred to as "nitride film 107".

[0018] In the example shown in Figure 2B, no fluorine is adsorbed on the first region 101. However, a small amount of fluorine may be adsorbed on the first region 101 compared to the amount of fluorine adsorbed on the second region 102.

[0019] Another treatment for removing the native oxide film 105 is, for example, a DHF (Dilute Hydrogen Fluoride) treatment using diluted hydrogen fluoride. However, the DHF treatment is a solution treatment. Therefore, after removing the native oxide film 105 by the DHF treatment, when forming a nitride film 107 on the first region 101, it is necessary to remove the substrate 100 from the treatment apparatus that performed the DHF treatment. At this time, the substrate 100 is exposed to the atmosphere. As a result, there is a possibility that a new native oxide film 105 will be formed on the first region 101 and the second region 102. However, in this embodiment, since the native oxide film 105 present on at least the first region 101 is removed by the COR treatment, the possibility of a new native oxide film 105 being formed on the first region 101 can be reduced. Furthermore, by exposing the substrate 100 to the fluorine-containing gas used in the COR treatment, the nitride film 107 can be selectively formed on the first region 101 in step S14 described later. This reduces the number of processing steps in the embodiment and improves productivity. Furthermore, the COR treatment and, for example, the process of forming the nitride film 107 in step S14 can be performed in the same treatment container or within the same processing apparatus without exposure to the atmosphere. This further improves productivity.

[0020] An example of the processing conditions for step S12 is as follows: • Flow rate of fluorine-containing gas: 100 sccm to 2000 sccm • Flow rate of basic gas: 100 sccm to 2000 sccm • Processing pressure: 0.05 Torr to 5 Torr (6 Pa to 666 Pa) • Temperature of substrate 100 during COR processing: 50°C to 100°C • Temperature of substrate 100 during PHT processing: 200°C to 600°C

[0021] Step S13 is performed after step S12. Figure 2C is a schematic cross-sectional view showing an example of the substrate 100 after fluorine 103b has been adsorbed onto the second region 102. Step S13 includes maintaining the temperature of the substrate 100 at a first temperature of 600°C or higher, supplying a fluorine-containing gas to the substrate 100, and adsorbing fluorine 103b onto the second region 102 as shown in Figure 2C.

[0022] In step S13, the substrate 100 is exposed to a fluorine-containing gas while its temperature is maintained in a relatively high temperature range of 600°C or higher, corresponding to the first temperature. This allows for the adsorption of fluorine 103b in addition to the fluorine 103a adsorbed in step S12. That is, a sufficient amount of fluorine 103a and 103b can be adsorbed on the second region 102. As a result, the formation of a nitride film 107 on the second region 102 in step S14, described later, can be reliably inhibited. Note that in the example shown in Figure 2C, no fluorine is adsorbed on the first region 101. However, a small amount of fluorine may be adsorbed on the first region 101 compared to the amount of fluorine 103a and 103b adsorbed on the second region 102.

[0023] The first temperature is preferably 600°C to 800°C. More preferably, the first temperature is 600°C to 700°C, and even more preferably 600°C to 650°C. By setting the first temperature to 600°C to 800°C, fluorine 103a and 103b can be reliably adsorbed onto the second region 102, and the possibility of fluorine 103a and 103b desorbing from the second region 102 can be reduced. Furthermore, step S13 can be carried out at, for example, the same temperature as the temperature required to form a good quality nitride film 107 in step S14. Good quality means having the desired properties of the nitride film 107, high uniformity of film thickness, etc.

[0024] The fluorine-containing gas supplied in step S13 may be fluorine molecules or fluorine compounds as exemplified in the COR treatment of step S12. In particular, the fluorine-containing gas supplied in step S13 preferably contains hydrogen fluoride. By containing hydrogen fluoride in the fluorine-containing gas supplied in step S13, sufficient fluorine 103a and 103b can be adsorbed on the second region 102 even when the temperature of the substrate 100 is maintained in a relatively high temperature range corresponding to the first temperature. Furthermore, by containing hydrogen fluoride in the fluorine-containing gas supplied in step S13, the possibility of etching of the surface of the first region 101 and the surface of the second region 102 can be reduced. As a result, in step S14 described later, a nitride film 107 having a film thickness approximately as designed can be formed on the first region 101.

[0025] An example of the processing conditions for step S13 is as follows: • Flow rate of fluorine-containing gas: 100 sccm to 5000 sccm • Processing pressure: 0.05 Torr to 50 Torr (6 Pa to 6666 Pa) • Temperature of substrate 100 (first temperature): 600°C to 800°C

[0026] Step S14 is performed after step S13. Figure 2D is a schematic cross-sectional view showing an example of the substrate 100 after the nitride film 107 has been deposited on the first region 101. Step S14 includes maintaining the temperature of the substrate 100 at a second temperature of 600°C or higher, supplying a film-forming gas to the substrate 100, and depositing the nitride film 107 on the first region 101 as shown in Figure 2D. The nitride film 107 is, for example, a silicon nitride film. Alternatively, the nitride film 107 may be a germanium nitride film or a metal nitride film. The metal nitride film may contain metal elements similar to those exemplified in the nitride film of the first region 101.

[0027] In step S14, it is preferable to deposit the nitride film 107 using the ALD (Atomic Layer Deposition) method. That is, the deposition gas supplied in step S14 preferably contains a raw material gas and a reaction gas containing nitrogen. Furthermore, it is preferable to supply the raw material gas and the reaction gas alternately multiple times in step S14. By using the ALD method, a conformal nitride film 107 can be deposited. However, in step S14, a method other than the ALD method, such as the CVD (Chemical Vapor Deposition) method, may be used.

[0028] In step S14, the source gas contains a silicon compound. An example of a silicon compound is monochlorosilane (SiH ３ Cl), dichlorosilane (SiH ２ Cl ２ ), trichlorosilane (SiHCl ３ ), tetrachlorosilane (SiCl ４ ), hexachlorodisilane (Si ２ Cl ６ ) and other chlorine-containing silane compounds, tetrabromosilane (SiBr ４ Bromine-containing silane compounds such as ) and tetraiodosilane (SiI ４ Examples of iodine-containing silane compounds include (SiH). In other words, the silicon compound may be a halogen-containing compound. Another example of a silicon compound is monosilane (SiH). ４ ) and disilane (Si ２ H ６ Examples of hydride silane compounds include (GeCl) and others. When the nitride film 107 is a germanium nitride film, the source gas contains a germanium compound. An example of a germanium compound is germanium tetrachloride (GeCl). ４ Examples include: When the nitride film 107 is a metal nitride film, the raw material gas contains a metal-containing compound. An example of a metal-containing compound is aluminum trichloride (AlCl ３ ), Titanium tetrachloride (TiCl ４ ), molybdenum pentachloride (MoCl ５ ), tungsten hexachloride (WCl ６) etc. can be mentioned. Further, as an example of a reaction gas containing nitrogen, ammonia (NH ３ ), hydrazine (N ２ H ４ ), and hydrazine derivatives such as monomethylhydrazine can be mentioned.

[0029] In step S14, with the temperature of the substrate 100 maintained in a relatively high temperature range of 600°C or higher corresponding to the second temperature, the substrate 100 is exposed to the film-forming gas. Thereby, a nitride film 107 with good film quality can be formed on the first region 101. Further, since a sufficient amount of fluorine 103a, 103b is adsorbed on the second region 102 in step S13, it is possible to reduce the possibility of so-called selective breakage where a nitride film is formed on the second region 102.

[0030] The second temperature is preferably 600°C or higher and 800°C or lower. Among them, the second temperature is more preferably 600°C or higher and 700°C or lower, and even more preferably 600°C or higher and 650°C or lower. When the second temperature is 600°C or higher and 800°C or lower, a nitride film 107 with good film quality can be formed on the first region 101. Further, since the substrate 100 is not heated excessively, the power cost can be reduced.

[0031] In step S14, it is preferable to use the same processing container as that used in step S13. Further, it is more preferable to perform steps S12, S13, and S14 in the same processing container. Also, the temperature difference between the first temperature and the second temperature is preferably 100°C or less. Among these, the temperature difference between the first temperature and the second temperature is preferably 50°C or less, and more preferably 10°C or less. By setting the temperature difference between the first temperature and the second temperature as described above, the temperature adjustment time of the substrate 100 from step S13 to step S14 can be shortened. Thereby, the implementation period from the start point of step S13 to the end point of step S14 can be shortened, and the productivity can be further improved. Note that "the temperature difference between the first temperature and the second temperature is 100°C or less" includes the case where there is no temperature difference between the first temperature and the second temperature, that is, the case where the first temperature and the second temperature are the same. The same applies to the cases of "the temperature difference between the first temperature and the second temperature is 50°C or less" and "the temperature difference between the first temperature and the second temperature is 10°C or less".

[0032] In step S14, it is preferable to supply the film-forming gas without plasmaizing it. By supplying the film-forming gas without plasmaizing it, the desorption of the fluorine 103a, 103b adsorbed on the second region 102 can be suppressed.

[0033] The supply time of the film-forming gas in step S14 can be arbitrarily set within a range not exceeding the incubation time when the nitride film 107 starts to be formed on the second region 102. Note that the incubation time may vary depending on the type of the oxide film in the second region 102. Therefore, the supply time of the film-forming gas in step S14 is preferably set according to the type of the oxide film in the second region 102.

[0034] An example of the processing conditions in step S14 is as follows. - Flow rate of the source gas: 500 sccm to 2000 sccm - Flow rate of the reaction gas: 1000 sccm to 10000 sccm - Processing pressure: 0.05 Torr to 20 Torr (6 Pa to 2666 Pa) - Temperature of the substrate 100 (second temperature): 600°C to 800°C

[0035] Step S15 alternately repeats steps S13 and S14. In step S15, steps S13 and S14 are repeated alternately until the number of repetitions of steps S13 and S14 reaches a set number N. This ensures that even if the amount of fluorine 103a and 103b adsorbed on the second region 102 decreases when the process in step S14 is performed, the amount of fluorine 103a and 103b adsorbed on the second region 102 can be ensured by the subsequent process in step S13. As a result, the possibility of selective tearing can be reduced. In addition, the thickness of the nitride film 107 selectively formed on the first region 101 can be increased.

[0036] In step S15, the number of repetitions of step S13 and step S14 is preferably, for example, 5 to 20 times. If the number of repetitions of step S13 and step S14 is less than 5, it may not be possible to secure the thickness of the nitride film 107 that is selectively formed on the first region 101. Also, if the number of repetitions of step S13 and step S14 exceeds 20, selective failure may occur. However, the number of repetitions of step S13 and step S14 is not limited to 5 to 20 times. Furthermore, if a nitride film 107 of the desired thickness can be obtained by performing step S13 and step S14 once each, step S15 can be omitted.

[0037] [Examples] Next, examples will be described to further explain the film deposition method according to the embodiment. However, the film deposition method according to the embodiment is not limited to the following examples. Specifically, as shown in Figure 3, the relationship between the number of repetitions of step S13 and step S14 (hereinafter referred to as "number of repetitions") and the film thickness of the nitride film 107 on the first region 101 and the film thickness of the nitride film on the second region 102 was evaluated. The film thickness of the nitride film 107 on the first region 101 and the film thickness of the nitride film on the second region 102 were measured using a spectroscopic ellipsometer. Figure 3 is a graph showing an example of the relationship between the number of repetitions and the film thickness (Å) of the nitride film 107 on the first region 101 and the film thickness (Å) of the nitride film on the second region 102. In Figure 3, the plots indicated by circles indicate the film thickness of the nitride film 107 on the first region 101. The solid line shows the change in the film thickness of the nitride film 107 deposited on the first region 101. The plots indicated by triangles indicate the film thickness of the nitride film on the second region 102. The dashed line shows the change in the thickness of the nitride film deposited on the second region 102.

[0038] In this example, the nitride film in the first region 101 of the substrate 100 is a silicon nitride film. The oxide film in the second region 102 of the substrate 100 is a silicon oxide film. In step S13, a fluorine-containing gas containing hydrogen fluoride was supplied, and in step S14, a silicon nitride film was formed as nitride film 107 using the ALD method. At this time, a raw material gas containing dichlorosilane and a reaction gas containing ammonia were supplied as the film-forming gas.

[0039] As shown by the solid line in Figure 3, a nitride film 107 was formed on the first region 101 when the number of repetitions was one or more. Furthermore, the thickness of the nitride film 107 increased with increasing repetitions. In addition, it was confirmed that when the number of repetitions was five, the thickness of the nitride film 107 was approximately 50 Å, ensuring a sufficient thickness of nitride film 107. In other words, it is preferable to have five or more repetitions.

[0040] In contrast, as shown by the dashed line in Figure 3, a nitride film was formed on the second region 102 after 22 repetitions. In other words, according to the example, when the number of repetitions was 21 or less, a nitride film 107 could be selectively formed on the first region 101, while when the number of repetitions was 22 or more, selective tearing occurred. Considering measurement errors and variations between measurements, it is preferable that the number of repetitions be 20 or less.

[0041] [Film Formation Method of the Second Embodiment] An example of a film formation method according to the second embodiment will be described with reference to Figure 4. Figure 4 is a flowchart of an example of a film formation method according to the second embodiment. The film formation method according to the second embodiment includes steps S21 to S26 shown in Figure 4. Step S21 may be the same as step S11 in the first embodiment. Step S22 may be the same as step S12 in the first embodiment. Step S24 may be the same as step S13 in the first embodiment. Step S25 may be the same as step S14 in the first embodiment. Step S26 may be the same as step S15 in the first embodiment.

[0042] In the second embodiment, step S23 is performed between step S22 and step S24. Step S23 includes supplying a second film-forming gas to the substrate 100 before adsorbing fluorine 103b onto the second region 102. The second film-forming gas supplied in step S23 may be the same as the film-forming gas supplied in step S25. Alternatively, the second film-forming gas supplied in step S23 may be different from the film-forming gas supplied in step S25.

[0043] By performing step S23, a thin film containing nitride (hereinafter referred to as "thin film") can be formed on the first region 101 before the nitride film 107 is formed in step S25. That is, the thin film on the first region 101 can be used as a seed layer to form the nitride film 107 in step S25. As a result, a nitride film 107 with sufficient thickness can be obtained even with a small number of repetitions in step S26.

[0044] In step S23, it is preferable to use the ALD method. That is, the second film-forming gas supplied in step S23 preferably contains a raw material gas and a reaction gas containing nitrogen. By using the ALD method, a conformal thin film can be formed. However, in step S23, a method other than the ALD method, such as the CVD method, may be used.

[0045] In step S23, the raw material gas exemplified in step S14 can be used as the raw material gas. Furthermore, the reaction gas exemplified in step S14 can be used as the reaction gas containing nitrogen.

[0046] In step S23, it is preferable to maintain the temperature of the substrate 100 at a third temperature of 600°C or higher. The temperature difference between the third temperature and the second temperature in steps S14 and S25 is preferably 0°C or more and 100°C or less. In this case, the temperature difference between the first temperature and the second temperature is preferably the same as the temperature difference exemplified in the first embodiment. Furthermore, in step S23, it is preferable to use the same processing container as the processing container used in steps S24 and S25. This makes it possible to shorten the temperature adjustment time of the substrate 100 from step S23 to step S25. As a result, the period from the start of step S23 to the end of step S25 can be shortened, and productivity can be further improved. Note that "the temperature difference between the third temperature and the second temperature is 100°C or less" includes the case where there is no temperature difference between the third temperature and the second temperature, i.e., the case where the third temperature and the second temperature are the same.

[0047] [Film Deposition Apparatus] Next, a film deposition apparatus 1 for carrying out the film deposition method according to the embodiment will be described with reference to Figures 5 and 6. The film deposition apparatus 1 is a batch-type vertical heat treatment apparatus that performs heat treatment on multiple substrates at once. Figure 5 is a schematic vertical cross-sectional view of the film deposition apparatus 1. Figure 6 is a schematic horizontal cross-sectional view of the film deposition apparatus 1.

[0048] The film deposition apparatus 1 comprises a processing container 110, a substrate holding unit 120, a heating unit 130, a gas supply unit 140, a gas discharge unit 150, and a control unit 160. The processing container 110 houses the substrate 100. The substrate holding unit 120 holds the substrate 100 inside the processing container 110. The heating unit 130 heats the substrate 100 held by the substrate holding unit 120. The gas supply unit 140 supplies gas to the inside of the processing container 110. The gas discharge unit 150 discharges gas from inside the processing container 110. The control unit 160 controls the heating unit 130, the gas supply unit 140, and the gas discharge unit 150 to carry out the film deposition method shown in Figure 1.

[0049] The processing container 110 is configured to accommodate a substrate 100 having a first region 101 and a second region 102. The processing container 110 is a vertical double tube having a cylindrical inner tube 111 and a cylindrical outer tube 112 that covers the outside of the inner tube 111. The inner tube 111 has an opening at its lower end and a horizontal ceiling at its upper end. The outer tube 112 has an opening at its lower end and a dome-shaped ceiling at its upper end. The inner tube 111 and the outer tube 112 are made of, for example, quartz or silicon carbide.

[0050] The processing container 110 further includes a cylindrical manifold 114. The manifold 114 is made of, for example, stainless steel. A flange portion 115 is formed at the upper end of the manifold 114. The lower end of the outer pipe 112 is installed on the flange portion 115. A sealing member 116, such as an O-ring, is placed between the flange portion 115 and the lower end of the outer pipe 112. An annular support portion 117 is provided on the inner wall of the upper part of the manifold 114. The lower end of the inner pipe 111 is installed on the support portion 117.

[0051] The processing container 110 further has a lid 118. The lid 118 closes the opening at the lower end of the manifold 114. A sealing member 119, such as an O-ring, is placed between the lid 118 and the lower end of the manifold 114. The lid 118 is made of, for example, stainless steel. A through hole is formed in the center of the lid 118, penetrating the lid 118 vertically. A rotating shaft 171 is placed in this through hole. The gap between the lid 118 and the rotating shaft 171 is sealed by a magnetic fluid seal 172. The lower end of the rotating shaft 171 is rotatably supported by an arm 182 of a lifting unit 181. A rotating plate 173 is provided at the upper end of the rotating shaft 171. A substrate holding unit 120 is installed on the rotating plate 173 via a warming stand 121.

[0052] The substrate holder 120 holds multiple substrates 100 at vertical intervals. Each of the multiple substrates 100 is held horizontally. When the lifting unit 181 is raised, the lid 118 and the substrate holder 120 rise, and the substrate holder 120 is brought into the processing container 110, and the opening at the lower end of the processing container 110 is sealed by the lid 118. When the lifting unit 181 is lowered, the lid 118 and the substrate holder 120 lower, and the substrate holder 120 is carried out to the outside of the processing container 110. When the rotating shaft 171 is rotated, the substrate holder 120 rotates together with the rotating plate 173.

[0053] The heating unit 130 is configured to raise the temperature of the substrate 100. The heating unit 130 heats the substrate 100 held by the substrate holding unit 120. The heating unit 130 is formed in a cylindrical shape outside the processing container 110. The heating unit 130 is, for example, an electric heater.

[0054] The gas supply unit 140 supplies gas into the inner pipe 111 of the processing container 110. The gas supply unit 140 supplies various gases used in steps S12 to S15 and steps S22 to S26 into the processing container 110. However, the type of gas is not limited to those mentioned above.

[0055] In the examples shown in Figures 5 and 6, the gas supply unit 140 includes a fluorine-containing gas supply unit 141, a basic gas supply unit 142, a raw material gas supply unit 143, and a reaction gas supply unit 144. The film-forming gas and the second film-forming gas include a raw material gas supplied by the raw material gas supply unit 143 and a reaction gas supplied by the reaction gas supply unit 144. The fluorine-containing gas supply unit 141 is used, for example, in steps S12, S13, S22, and S24. The basic gas supply unit 142 is used, for example, in steps S12 and S22. The raw material gas supply unit 143 and the reaction gas supply unit 144 are used, for example, in steps S14, S23, and S25.

[0056] The fluorine-containing gas supply unit 141 includes a gas supply pipe 141a inside the processing container 110 and a supply channel 141b outside the processing container 110. In the supply channel 141b, a fluorine-containing gas source 141c, a mass flow controller 141d, and a valve 141e are provided in order from the upstream side to the downstream side in the direction of gas flow. As a result, the supply timing of the fluorine-containing gas from the fluorine-containing gas source 141c is controlled by the valve 141e, and the flow rate is adjusted to a predetermined level by the mass flow controller 141d. The fluorine-containing gas flows from the supply channel 141b into the gas supply pipe 141a and is discharged from the gas supply pipe 141a into the processing container 110.

[0057] The basic gas supply unit 142 includes a gas supply pipe 142a inside the processing container 110 and a supply channel 142b outside the processing container 110. In the supply channel 142b, a basic gas source 142c, a mass flow controller 142d, and a valve 142e are provided in order from the upstream side to the downstream side in the direction of gas flow. As a result, the basic gas from the basic gas source 142c is supplied at a timing controlled by the valve 142e and adjusted to a predetermined flow rate by the mass flow controller 142d. The basic gas flows from the supply channel 142b into the gas supply pipe 142a and is discharged from the gas supply pipe 142a into the processing container 110.

[0058] The raw material gas supply unit 143 includes a gas supply pipe 143a inside the processing container 110 and a supply channel 143b outside the processing container 110. In the supply channel 143b, a raw material gas source 143c, a mass flow controller 143d, and a valve 143e are provided in order from the upstream side to the downstream side in the direction of gas flow. As a result, the supply timing of the raw material gas from the raw material gas source 143c is controlled by the valve 143e, and the flow rate is adjusted to a predetermined level by the mass flow controller 143d. The raw material gas flows from the supply channel 143b into the gas supply pipe 143a and is discharged from the gas supply pipe 143a into the processing container 110.

[0059] The reaction gas supply unit 144 includes a gas supply pipe 144a inside the processing container 110 and a supply channel 144b outside the processing container 110. In the supply channel 144b, a reaction gas source 144c, a mass flow controller 144d, and a valve 144e are provided in order from upstream to downstream in the direction of gas flow. As a result, the reaction gas from the reaction gas source 144c is supplied at a timing controlled by the valve 144e and adjusted to a predetermined flow rate by the mass flow controller 144d. The reaction gas flows from the supply channel 144b into the gas supply pipe 144a and is discharged from the gas supply pipe 144a into the processing container 110.

[0060] Each gas supply pipe 141a, 142a, 143a, and 144a is fixed to the manifold 114. Each gas supply pipe 141a, 142a, 143a, and 144a is made of, for example, quartz. Each gas supply pipe 141a, 142a, 143a, and 144a extends linearly along the vertical direction near the inner pipe 111 and then bends in an L-shape within the manifold 114 to extend horizontally, thereby penetrating the manifold 114. The gas supply pipes 141a, 142a, 143a, and 144a are arranged side by side along the circumferential direction of the inner pipe 111 and are formed at the same height.

[0061] As shown in Figure 6, multiple discharge ports 141f, 142f, 143f, and 144f are provided in the portions located within the inner tube 111 of each of the gas supply pipes 141a, 142a, 143a, and 144a. A housing portion 111a is formed on the side wall of the inner tube 111 along the longitudinal direction (the vertical direction of the film deposition apparatus 1) to accommodate the gas supply pipes 141a, 142a, 143a, and 144a. For example, a part of the side wall of the inner tube 111 is made to protrude outward to form a convex portion 111b, and the inside of the convex portion 111b is formed as the housing portion 111a. Each discharge port 141f, 142f, 143f, and 144f is formed at predetermined intervals along the extending direction of each of the gas supply pipes 141a, 142a, 143a, and 144a. Each of the outlets 141f, 142f, 143f, and 144f discharges gas horizontally from the radially outer side of the substrate 100 toward the substrate 100. Each of the outlets 141f, 142f, 143f, and 144f discharges gas parallel to the main surface of the substrate 100. The spacing between the outlets is set to be the same as, for example, the spacing between the substrates 100 held by the substrate holding part 120. The height position of each outlet is set to be, for example, an intermediate position between adjacent substrates 100 in the vertical direction. In this case, each outlet can efficiently supply gas to the opposing surfaces between adjacent substrates 100.

[0062] The gas supply unit 140 may mix multiple types of gases and discharge the mixed gas from a single gas supply pipe. Each gas supply pipe 141a, 142a, 143a, and 144a may have a different shape or arrangement from one another. The gas supply unit 140 may further include a gas supply pipe for supplying another gas.

[0063] The gas discharge section 150 discharges gas from inside the processing container 110. An exhaust port 113 is formed in the inner tube 111 to exhaust the gas from inside the inner tube 111. The exhaust port 113 is positioned opposite the discharge ports 141f to 144f (see Figure 6). The gas discharged horizontally from the discharge ports 141f to 144f passes through the exhaust port 113, descends along the inner wall of the outer tube 112, and is exhausted from the exhaust pipe 151.

[0064] The gas discharge section 150 includes an exhaust pipe 151, a vacuum pump 152, and a pressure controller 153. The exhaust pipe 151 connects the exhaust port of the manifold 114 to the vacuum pump 152. The vacuum pump 152 draws gas from inside the processing container 110. The pressure controller 153 is installed in the middle of the exhaust pipe 151 and controls the air pressure inside the processing container 110.

[0065] The control unit 160 may be one or more circuits, or it may be provided as a single unit or in parts. The control unit 160 may be, for example, a computer and may include a CPU (Central Processing Unit) 161 and a storage medium 162 such as memory. The storage medium 162 stores programs that control various processes performed in the film deposition apparatus 1. The control unit 160 controls the operation of the film deposition apparatus 1 by causing the CPU 161 to execute the programs stored in the storage medium 162. Examples of the storage medium 162 include ROM (Read-only memory), HDD (Hard Disk Drive), SSD (Solid State Drive), flash memory, and EEPROM (Electrically Erasable Programmable Read-Only Memory).

[0066] In the example shown in Figure 5, the control unit 160 is equipped with a CPU 161 as the arithmetic processing unit, but it may also be equipped with an electronic circuit having arithmetic processing functions such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit).

[0067] The control unit 160 controls the gas supply unit 140 and the heating unit 130 to execute steps S12 to S15 and steps S22 to S26.

[0068] Note that the film deposition apparatus 1 is not limited to the vertical heat treatment apparatus shown in Figures 5 and 6. For example, the film deposition apparatus 1 may be a single-wafer type apparatus that processes substrates 100 one at a time. Alternatively, the film deposition apparatus 1 may be a semi-batch type apparatus. In a semi-batch type apparatus, multiple substrates 100 arranged around the rotation centerline of a rotary table are rotated together with the rotary table and passed sequentially through multiple regions to which different gases are supplied.

[0069] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The above embodiments may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the appended claims.

[0070] This international application claims priority based on Japanese Patent Application No. 2025-025614, filed on 20 February 2025, and the entire contents of said application are incorporated herein by reference.

[0071] 100 Substrate 101 First region 102 Second region 103a, 103b Fluorine 105 Native oxide film 107 Nitride film

Claims

1. A film formation method comprising: (a) preparing a substrate having a first region where a nitride film is exposed and a second region where an oxide film is exposed; (b) maintaining the temperature of the substrate at a first temperature of 600°C or higher and supplying a fluorine-containing gas to the substrate to adsorb fluorine onto the second region; and (c) maintaining the temperature of the substrate at a second temperature of 600°C or higher and supplying a film-forming gas to the substrate to form a new nitride film on the first region.

2. The film formation method according to claim 1, wherein the temperature difference between the first temperature and the second temperature is 100°C or less.

3. The film formation method according to claim 1, wherein the temperature difference between the first temperature and the second temperature is 10°C or less.

4. A film-forming method according to any one of claims 1 to 3, wherein step (b) and step (c) are performed in the same processing container.

5. (d) A method for forming a film according to any one of claims 1 to 3, further comprising the step of supplying a fluorine-containing gas and a basic gas to the substrate between step (a) and step (b) to remove the native oxide film on at least the first region.

6. The film formation method according to claim 5, wherein steps (b), (c), and (d) are performed in the same processing container.

7. The film-forming method according to any one of claims 1 to 3, wherein the fluorine-containing gas supplied in step (b) includes hydrogen fluoride.

8. (e) A method for forming a film according to any one of claims 1 to 3, further comprising the step of alternately repeating step (b) and step (c).

9. The film deposition method according to any one of claims 1 to 3, wherein in step (c), the film deposition gas is supplied without being plasma-formed.

10. The film-forming method according to any one of claims 1 to 3, wherein the film-forming gas comprises a raw material gas and a reaction gas containing nitrogen, and in step (c), the raw material gas and the reaction gas are supplied alternately multiple times.

11. (f) The film formation method according to any one of claims 1 to 3, further comprising the step of supplying a second film formation gas to the substrate between step (a) and step (b).

12. A film deposition apparatus comprising: a processing container configured to accommodate a substrate having a first region where a nitride film is exposed and a second region where an oxide film is exposed; a gas supply unit for supplying gas into the processing container; a heating unit configured to raise the temperature of the substrate; and a control unit, wherein the control unit controls the gas supply unit and the heating unit to perform the following steps: maintaining the temperature of the substrate at a first temperature of 600°C or higher and supplying a fluorine-containing gas to the substrate to adsorb fluorine onto the second region; and maintaining the temperature of the substrate at a second temperature of 600°C or higher and supplying a film-forming gas to the substrate to form a new nitride film on the first region.

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