Method for forming group VI transition metal films

Abstract

We provide high-quality metal films. [Solution] A film deposition method for forming a VI transition metal film on a substrate placed in a film deposition chamber, wherein ammonia is supplied to the film deposition chamber, an organic VI transition metal is supplied to the film deposition chamber, and the VI transition metal film is formed on the substrate, which is heated to a temperature of 1000°C or higher, from the ammonia supplied to the film deposition chamber and the organic VI transition metal.

Description

[Technical Field] 【0001】 The present invention relates to a method for forming a single-composition group VI transition metal (e.g., Mo) film with excellent crystallinity. [Background technology] 【0002】 Mo (molybdenum) possesses excellent physical properties such as a high melting point, low thermal expansion coefficient, low resistivity, and high thermal conductivity. Therefore, it is used in the manufacture of semiconductor devices for diffusion barriers, electrodes, photomasks, power electronics device substrates, and low-resistance gates and connects. Based on the above characteristics, it is expected to be used as a metal wiring to connect layers in gates, electrodes of metal-oxide-semiconductor electrolytic transistors (MOSFETs), and in the middle-of-line (MOL) and / or back-end-of-the-line (BEOL) regions. 【0003】 Japanese Patent Publication No. 2023-134421 proposes a method for depositing a conductive metal onto a substrate from a metal-containing precursor, comprising vaporizing the metal-containing precursor, flowing the vaporized precursor into a deposition chamber, flowing a reducing co-reactant gas into the deposition chamber, and flowing a gaseous nitrogen-containing reducing compound into the deposition chamber in order to deposit the metal of the precursor onto the substrate in the deposition chamber. Here, the reducing co-reactant is, for example, hydrogen (H2), and the nitrogen-containing reducing compound is H-NR1R2 [where R1 and R2 are each H, R1 is H and R2 is a lower alkyl, R1=NH2 and R2 is H, R1 is a lower alkyl and R2 is a lower alkyl, or R1 and R2 are bonded to form a nitrogen-containing cyclic compound]. The aforementioned metal-containing precursor is a halide or an oxyhalide. The nitrogen-containing reducing compound is selected from ammonia (NH3), alkylamines (e.g., methylamine, ethylamine, propylamine, t-butylamine), dialkylamines, pyridine, hydrazine, and alkylated hydrazine. In other words, the invention discloses a method in which inorganic materials, a reducing agent (e.g., H2), and a nitrogen-containing agent (e.g., NH3) are used. 【0004】 Japanese Patent Publication No. 2022-523689 proposes a method comprising the steps of depositing a first layer from a metal chloride precursor and ammonia using a first atomic layer deposition (ALD) process, and depositing an elemental metal layer on the first layer from a metal chloride precursor and hydrogen using a second ALD process. The first layer is a metal oxynitride layer or a metal nitride layer. It is not a metal film. 【0005】 Chem.Mater.2007,19,2,263-269 proposes a film deposition method using (tBuN)2Mo(NMe2)2 and NH3. The film obtained in this method was a nitride film, not a metallic film. 【0006】 The Journal of Alloys and Compounds (Volume 858, 25 March 2021, 158314) proposes a film deposition method using Mo(CO)6 and NH3 plasma. The film obtained in this method was a nitride film, not a metallic film. 【0007】 The Journal of Alloys and Compounds (Volume 663, 5 April 2016, 651-658) proposes a film deposition method using (tBuN)2Mo(StBu)2 and H2 plasma. The film obtained in this method was a nitride film, not a metallic film. 【0008】 J. Vac. Sci. Technol. (A 41, 012405 (2023)) proposed a film deposition method using Mo(EtBen)2 and H2. The film obtained in this method was a carbide film, not a metallic film. [Prior art documents] [Patent Documents] 【0009】 [Patent Document 1] Japanese Patent Publication No. 2023-134421 [Patent Document 2] Japanese Patent Laid-Open No. 2022-523689 [Non-Patent Document] 【0010】 [Non-Patent Document 1] Chem. Mater. 2007, 19, 2, 263 - 269 [Non-Patent Document 2] Journal of Alloys and Compounds, Volume 858, 25 March 2021, 158314 [Non-Patent Document 3] Journal of Alloys and Compounds, Volume 663, 5 April 2016, 651 - 658 [Non-Patent Document 4] J. Vac. Sci. Technol. A 41, 012405(2023) [Summary of the Invention] [Problems to be Solved by the Invention] 【0011】 As materials (precursors) for forming a Mo metal film, inorganic precursors (e.g., Mo halides (MoF6, MoCl5), Mo(CO)6, MoO2Cl2, etc.) or organic precursors (e.g., imide / amide Mo (e.g., (tBuN)2Mo(NMe2)2, etc.)) have been studied. 【0012】 When an inorganic metal material (e.g., a metal halide) is used as the precursor, since C and N are generally not contained in the inorganic metal material, it is considered that the impurities in the formed film are less than when an organometallic material is used as the precursor. By the way, when forming a Mo metal film using the halogenated Mo as the precursor, H2 is used. Therefore, hydrogen halides (HX such as HF and HCl) are generated. The generated HX etches the growing Mo film. The X (F, Cl) remains in the Mo film. The remaining X (F, Cl) increases the resistance of the Mo film. Therefore, it cannot be said that the use of the halogenated Mo is preferable. 【0013】 Even when forming a Mo metal film using the oxyhalogenated Mo (MoO2Cl2) as the precursor, H2 is used. Therefore, HCl is generated. The same problems as those in the case of using the halogenated Mo occur. Moreover, it is difficult to remove the double bond between O and Mo. Therefore, O remains in the film. The remaining O increases the resistance of the Mo film. Therefore, it cannot be said that the use of the oxyhalogenated Mo is preferable. 【0014】 Even when forming a Mo metal film using the imide / amide Mo{(tBuN)2Mo(NMe2)2} as the precursor, H2 is used. The organic molecules generated at that time remain in the Mo film. Such organic residues increase the resistance. Moreover, it is difficult to remove the double bond between N and Mo. Therefore, N remains in the film. The remaining N increases the resistance of the Mo film. Therefore, it cannot be said that the use of the imide / amide Mo is preferable. 【0015】 Japanese Patent Application Laid-Open No. 2023-134421 proposes using a halide (or oxyhalide) as the precursor and using H2 and H-NR 1 R 2 (for example, NH3) as the reducing gas. Even with this proposed technique, since H2 is used, the above problems will still be inevitable. Also, this proposed technique solves the above problems by collecting the hydrogen halide generated by using H2 with H-NR 1 R 2 . That is, the direct role for forming the Mo metal film is H2. If organic Mo is used instead of the aforementioned halogenated Mo (or oxyhalogenated Mo), MoCx is produced by the reaction of organic Mo with H2 (plasma H2). When NH3 is added to this reaction, MoNx films or MoCxNy are formed. A Mo metal film will not be obtained. 【0016】 Therefore, it was difficult to deposit Mo metal films on a substrate using a single reducing gas. In particular, it was difficult to deposit Mo metal films on a substrate using organic Mo materials (precursors) as the material (precursor) for depositing the Mo metal film. 【0017】 For film deposition processes such as CVD and ALD to function effectively, it is crucial to generate vapor containing appropriately controlled amounts of reactive chemicals. When the precursor is solid, the amount of vapor generated depends on the particle size and shape. Therefore, maintaining a uniform vapor generation rate is difficult. This can potentially alter the growth rate and composition of the film formed on the substrate. Therefore, it can be understood that a liquid precursor is preferable for forming high-quality films. For example, organometallic compounds would be selected as liquid precursors. 【0018】 The problem that this invention aims to solve is to propose a technology that enables the formation of high-quality metal films when an organometallic compound is selected as the precursor. [Means for solving the problem] 【0019】 The present invention A film deposition method for forming a VI transition metal film on a substrate placed in a film deposition chamber, Ammonia is supplied into the aforementioned film deposition chamber. Organic group VI transition metals are supplied into the aforementioned film deposition chamber. On the substrate heated to a temperature of 935°C or higher, the VI transition metal film is formed from the ammonia supplied into the film deposition chamber and the organic group VI transition metal. We propose a film deposition method. 【0020】 The invention, in particular, A film deposition method for forming a VI transition metal film on a substrate placed in a film deposition chamber, Ammonia is supplied into the aforementioned film deposition chamber. Organic group VI transition metals are supplied into the aforementioned film deposition chamber. On the substrate heated to a temperature of 1000°C or higher, the VI transition metal film is formed from the ammonia supplied to the film deposition chamber and the organic group VI transition metal. We propose a film deposition method. 【0021】 The present invention proposes a film formation method wherein the heating temperature of the substrate is preferably 1300°C or lower. 【0022】 The present invention proposes a film deposition method, preferably one in which ammonia is supplied into the film deposition chamber before the organic group VI transition metal is supplied. 【0023】 The present invention proposes a film deposition method, preferably one in which the pressure inside the film deposition chamber is 800 Pa or less. 【0024】 The present invention proposes a film deposition method, preferably one in which CVD (Chemical Vapor Deposition) is used for film deposition. 【0025】 The present invention proposes a film deposition method, preferably one in which laser CVD is used for film deposition. 【0026】 The present invention proposes a film deposition method in which the organic group VI transition metal is, for example, (tBuN)2M(OtAm)2 [where M is Mo or W]. 【0027】 The present invention proposes a film deposition method in which the organic group VI transition metal is, for example, (tBuN)2M(OiPr)(OtAm) [where M is Mo or W]. 【0028】 The present invention is the above-described film-forming method, wherein the Group VI transition metal organic compound is, for example, (tBuN)2M(OR 2 )(OR 3 ). [M is Mo or W. R 2 , R 3 is an alkyl group having 2 to 5 carbon atoms.], and proposes a film-forming method. 【0029】 The present invention is the above-described film-forming method, wherein the Group VI transition metal organic compound is, for example, (R 1 N)2M(OR 2 )(OR 3 ). [M is Mo or W. R 1 , R 2 , R 3 is an alkyl group having 2 to 5 carbon atoms.], and proposes a film-forming method. 【0030】 The present invention is the above-described film-forming method, wherein the alkyl group of the Group VI transition metal organic compound is preferably a branched alkyl group, and proposes a film-forming method. [[ID=二十九]] [[ID=三十]] 【0031】 [[ID=三十一]] [[ID=三十二]]The present invention is the above-described film-forming method, wherein the formed Group VI transition metal film is, for example, a single-phase film, and proposes a film-forming method. [[ID=三十三]] [[ID=三十四]]【Effects of the Invention】[[ID=三十五]] [[ID=三十六]] [[ID=三十七]] 【0032】 [[ID=三十八]] [[ID=三十九]]According to the present invention, a high-quality metal film was obtained. For example, a Group VI transition metal film having a single composition with excellent crystallinity was obtained. [[ID=四十]] [[ID=四十一]]【Brief Description of the Drawings】[[ID=四十二]] [[ID=四十三]] [[ID=四十四]] 【0033】 [[ID=四十五]] [[ID=四十六]] [Figure 1] [[ID=四十七]]Schematic diagram of evaporation apparatus [[ID=四十八]] [[ID=四十九]] [Figure 2] [[ID=五十]]XRD diffraction pattern of Example 1 [[ID=五十一]] [[ID=五十二]] [Figure 3] [[ID=五十三]]XRD diffraction pattern of Example 4 [[ID=五十四]] [[ID=五十五]] [Figure 4] [[ID=五十六]]XRD diffraction pattern of Reference Example 2 [[ID=五十七]] [[ID=五十八]] [Figure 5] [[ID=五十九]]XRD diffraction pattern of Reference Example 4 [[ID=六十]] [[ID=六十一]] [[ID=六十二]]【Modes for Carrying Out the Invention】[[ID=六十三]] [[ID=六十四]] 【0034】 The following detailed description provides only preferred exemplary embodiments and is not intended to limit the scope, applicability, or configuration of the invention. Rather, it provides to those skilled in the art an explanation for carrying out / making possible preferred exemplary embodiments of the invention. Various modifications can be made in the function and arrangement of the elements without departing from the spirit and scope of the invention as set forth in the appended claims. 【0035】 The present invention relates to a film deposition method for forming a VI transition metal film. The method involves forming a VI transition metal film on a substrate placed in a deposition chamber. The metal film is, for example, The film is a Mo film, or a W film. The deposited metal film was, for example, a single-phase film, or a single-composition transition metal film with excellent crystallinity. The method includes an ammonia supply step in which ammonia is supplied into the deposition chamber. The method also includes an organic VI transition metal supply step in which an organic VI transition metal (precursor) is supplied into the deposition chamber. A carrier gas (for example, N2) is supplied to the precursor, and the precursor is transported into the deposition chamber by bubbling. The ammonia supply step and the organic VI transition metal supply step can be performed in any order, or simultaneously. However, preferably, the organic VI transition metal is supplied after the ammonia is supplied into the deposition chamber. The method also includes a step of heating the substrate (sometimes called a substrate or base). The conditions in the deposition chamber (temperature, pressure, and especially temperature) affected the reaction between the precursor supplied into the deposition chamber and NH3. That is, the composition of the deposited film varied greatly depending on the substrate temperature. A VI transition metal film was deposited on the substrate, which was heated to a temperature of 935°C or higher, more preferably 1000°C or higher, and particularly 1050°C or higher, from the ammonia and the organic VI transition metal supplied into the deposition chamber. By-products in the deposition (film formation) process are removed by a carrier gas passing through the deposition chamber. Although there are no particular restrictions on the upper limit of the heating temperature, excessively high temperatures can damage the substrate or increase energy costs. Therefore, a temperature of 1300°C or lower is sufficient. The pressure inside the deposition chamber was preferably 800 Pa or lower. More preferably 700 Pa or lower. Even more preferably 500 Pa or lower. Still more preferably 300 Pa or lower. Particularly preferably 200 Pa or lower. In the embodiments described later, ammonia and the precursor are supplied at equal pressure, but 1 / 4 ≤ (ammonia supply pressure / precursor supply pressure) ≤ 4 / 1 is also acceptable. Preferably, 1 / 2 ≤ (ammonia supply pressure / precursor supply pressure). More preferably, 1 ≤ (ammonia supply pressure / precursor supply pressure). When the pressure inside the deposition chamber was high, for example, exceeding 800 Pa, a nitride film was formed. CVD technology was used for film deposition. In particular, laser CVD technology was used.By-products in the deposition process are removed by carrier gas passing through the deposition chamber. The aforementioned precursor is, for example, (R 1 N)2M(OR 2 )(OR 3 )[R 1 ,R 2 ,R 3 It is an alkyl group with 2 to 5 carbon atoms. For example, (tBuN)2M(OR 2 )(OR 3 )[R 2 ,R 3 The alkyl group was an alkyl group having 2 to 5 carbon atoms. The alkyl group was preferably a branched alkyl group. For example, (tBuN)2M(OiPr)(OtAm). For example, (tBuN)2M(OtAm)2. The M was, for example, Mo or W. Then, a high-quality metal film was deposited on the substrate using the method described above. 【0036】 The present invention will be described in more detail below. The following description is merely a preferred exemplary embodiment and does not limit the present invention. Various modifications are also possible, without departing from the spirit and scope of the invention as set forth in the claims. 【0037】 [Example 1] NH3 was supplied (100 sccm) into the deposition chamber (reactor), and the pressure inside the chamber was adjusted to 60 Pa. The Si substrate placed inside the deposition chamber was heated to 1058°C by a semiconductor laser. After this, 50 sccm of the precursor ((tBuN)2Mo(OtAm)2 [bis(t-amyloxy)bis(t-butylimide)molybdenum]) was supplied into the deposition chamber (reactor), and the pressure inside the chamber was adjusted to 120 Pa. The precursor was heated to 50°C. The precursor was supplied by bubbling N2 gas. As a result, a film was formed on the Si substrate. According to X-ray diffraction (XRD), the aforementioned film was a highly crystalline Mo metal film. The XRD diffraction pattern is shown in Figure 2. In addition to the peaks originating from the Si substrate, diffraction peaks at (110), (200), and (211) were observed. These are characteristic diffraction peaks that appear in the Mo metal phase. Therefore, it is composed solely of the Mo metal phase. In other words, the film was a single Mo metal film with excellent crystallinity. 【0038】 [Example 2] The procedure was carried out in the same manner as in Example 1, except that the heating temperature of the Si substrate was changed to 1152°C. As a result, a film was formed on the Si substrate. X-ray diffraction (XRD) of the aforementioned film revealed diffraction peaks at (110), (200), and (211) in addition to the peak originating from the Si substrate. These are characteristic diffraction peaks that appear in the Mo metal phase. Therefore, the film is composed solely of the Mo metal phase. In other words, the film was a single Mo metal film with excellent crystallinity. 【0039】 [Example 3] The procedure was carried out in the same manner as in Example 1, except that the heating temperature of the Si substrate was changed to 1213°C. As a result, a film was formed on the Si substrate. X-ray diffraction (XRD) of the aforementioned film revealed diffraction peaks at (110), (200), and (211) in addition to the peak originating from the Si substrate. These are characteristic diffraction peaks that appear in the Mo metal phase. Therefore, the film is composed solely of the Mo metal phase. In other words, the film was a single Mo metal film with excellent crystallinity. 【0040】 [Example 4] The procedure was carried out in the same manner as in Example 1, except that the heating temperature of the Si substrate was changed to 937°C. As a result, a film was formed on the Si substrate. Figure 3 shows the XRD diffraction pattern. According to X-ray diffraction (XRD), in addition to the peak originating from the Si substrate, diffraction peaks (110), (200), (211), (111), (200), and (220) were observed in the film. The (110), (200), and (211) peaks are characteristic diffraction peaks that appear in the Mo metal phase. However, the (111), (200), and (220) peaks are characteristic diffraction peaks that appear in the c-Mo2N phase. In other words, the film was composed of a Mo metal phase and a Mo nitride phase (c-Mo2N). That is, the film was not a single Mo metal film. 【0041】 [Example 5] The procedure was carried out in the same manner as in Example 1, except that the heating temperature of the Si substrate was changed to 958°C. As a result, a film was formed on the Si substrate. X-ray diffraction (XRD) of the aforementioned film revealed diffraction peaks (110), (200), (211), (111), (200), and (220) in addition to the peak originating from the Si substrate. The (110), (200), and (211) peaks are characteristic diffraction peaks that appear in the Mo metallic phase. The (111), (200), and (220) peaks are characteristic diffraction peaks that appear in the c-Mo2N phase. In other words, the film was composed of a Mo metallic phase and a Mo nitride phase (c-Mo2N). Therefore, the aforementioned film was not a single Mo metallic film. 【0042】 [Reference example 1] The procedure was carried out in the same manner as in Example 1, except that the heating temperature of the Si substrate was changed to 932°C. As a result, a film was formed on the Si substrate. X-ray diffraction (XRD) of the aforementioned film revealed diffraction peaks at (111), (200), and (220) in addition to the peak originating from the Si substrate. These are characteristic diffraction peaks that appear in the c-Mo2N phase. In other words, the film consisted solely of a Mo nitride phase (c-Mo2N film). Therefore, the aforementioned film was not a single Mo metal film. 【0043】 [Reference example 2] The procedure was carried out in the same manner as in Example 1, except that the heating temperature of the Si substrate was changed to 895°C. As a result, a film was formed on the Si substrate. Figure 4 shows the diffraction pattern obtained by X-ray diffraction (XRD). According to XRD, in addition to the peak originating from the Si substrate, diffraction peaks at (111), (200), and (220) were observed in the film. These are characteristic diffraction peaks that appear in the c-Mo2N phase. In other words, the film consisted solely of a Mo nitride phase (c-Mo2N film). Therefore, the film was not a single Mo metal film. 【0044】 [Reference example 3] The procedure was carried out in the same manner as in Example 1, except that the heating temperature of the Si substrate was changed to 774°C. As a result, a film was formed on the Si substrate. X-ray diffraction (XRD) of the aforementioned film revealed diffraction peaks at (111), (200), and (220) in addition to the peak originating from the Si substrate. These are characteristic diffraction peaks that appear in the c-Mo2N phase. In other words, the film consisted solely of a Mo nitride phase (c-Mo2N film). Therefore, the aforementioned film was not a single Mo metal film. 【0045】 [Reference example 4] The procedure was carried out in the same manner as in Example 1, except that the heating temperature of the Si substrate was changed to 578°C. As a result, a film was formed on the Si substrate. Figure 5 shows the XRD diffraction pattern. According to XRD, in addition to the peak originating from the Si substrate, diffraction peaks at (111), (200), and (220) were observed in the film. These are characteristic diffraction peaks that appear in the c-Mo2N phase. In other words, the film consisted solely of a Mo nitride phase (c-Mo2N film). That is, the film was not a single Mo metal film. 【0046】 The results are summarized in Table 1. Table-1 Heating temperature (℃) Generation phase Example 1 1058 Mometal Example 2 1152 Mometal Example 3 1213 Mometal Example 4 937 Mometal+c-Mo2N Example 5 958 Mometal+c-Mo2N Reference example 1 932 c-Mo2N Reference example 2 895 c-Mo2N Reference example 3 774 c-Mo2N Reference example 4 578 c-Mo2N 【0047】 From Table 1 above, it can be seen that as the film deposition temperature increases, the phase changes from c-Mo2N to Mometal. In CVD processes using NH3 as a reactant (reducing agent), nitride films are generally predominantly formed. Nevertheless, no one could have predicted that a Mo metal film could be formed in a CVD process using NH3 as the reactant (reducing agent) (without substantially using H2). This was discovered for the first time through the present invention. Furthermore, this indicates that a CVD film deposition technique using organic Mo material as a precursor and using only NH3 as the reactant (reducing agent) (without substantially using H2) may be a better option. 【0048】 To illustrate the nature of the present invention, it will be understood that many further modifications, including details such as materials, processes, and components, described and shown herein can be made by those skilled in the art within the principles and scope of the present invention as expressed in the appended claims. 【0049】 The present invention is not intended to be limited to the examples and / or embodiments described above.

Claims

[Claim 1] A film deposition method for forming a VI transition metal film on a substrate placed in a film deposition chamber, Ammonia is supplied into the aforementioned film deposition chamber. An organic transition metal of group VI is supplied into the aforementioned film deposition chamber. On the substrate heated to a temperature of 935°C or higher, the VI transition metal film is formed from the ammonia supplied to the film deposition chamber and the organic VI transition metal. Film formation method. [Claim 2] The substrate is heated to a temperature of 1000°C or higher. The method for forming a film according to claim 1. [Claim 3] In the aforementioned film deposition chamber, hydrogen is not substantially supplied. The method for forming a film according to claim 2. [Claim 4] The organic transition metal is supplied to the film deposition chamber after ammonia has been supplied to it. The method for forming a film according to claim 3. [Claim 5] The pressure inside the film deposition chamber is 800 Pa or less. The method for forming a film according to claim 4. [Claim 6] CVD is used for film formation. The method for forming a film according to claim 1. [Claim 7] Laser CVD is used for film deposition. The method for forming a film according to claim 1. [Claim 8] The aforementioned organo-VI transition metal is (tBuN). ２ M (OtAm) ２ [M is either Mo or W.] A method for forming a film according to any one of claims 1 to 7. [Claim 9] The aforementioned organo-VI transition metal is (tBuN). ２ M(OiPr)(OtAm) [where M is Mo or W] A method for forming a film according to any one of claims 1 to 7. [Claim 10] The aforementioned organo-VI transition metal is (tBuN). ２ M (OR ２ ) ( OR ３ ) [M is Mo or W. R ２ , R ３ It is an alkyl group having 2 to 5 carbon atoms. A method for forming a film according to any one of claims 1 to 7. [Claim 11] The Group VI transition metal organic is (R １ N) ２ M(OR ２ )(OR ３ )) [M is Mo or W. R １ , R ２ , R ３ is an alkyl group having 2 to 5 carbon atoms.]. A method for forming a film according to any one of claims 1 to 7. [Claim 12] The deposited VI transition metal film is a single-phase film. A method for forming a film according to any one of claims 1 to 7.

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