Film deposition material, film deposition method, and new compound

Abstract

To provide a compound which can form a group VI transition metal film which is easy to be transported into a film deposition chamber when deposited by the CVD or ALD, is stable in storage stability, has less impurities, and is conformal.SOLUTION: A compound is liquid at 25°C (1 atmosphere), and is represented by formula (I). Formula (I) (wherein, M is a group VI element, NR1 has no Si, R1, R2, R3 is a 1-10C alkyl group, R2≠R3).SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to technology relating to, for example, Group VI metals. [Background technology]

[0002] Transition metal films are used in the semiconductor and electronics fields. The deposition techniques for forming said films (especially thin films) are for example CVD (Chemical Vapor Deposition) or ALD (Atomic Layer Deposition). Said techniques are as follows: A film (metal, metal oxide, metal nitride, metal silicide or similar) is formed on a substrate by decomposition of a precursor (metal organic compound).

[0003] JP 2000-119045 discloses Mo(CO)6, MoCl3, MoCl6, MoF6, MoO2Cl2, and MoOCl4.

[0004] JP2022-524041A discloses Mo2Ln [L is selected from the group consisting of amidate, amidinate and guanidinate ligands. n is 2 to 5.]

[0005] Patent No. 5913663 is It discloses JPEG2025020638000002.jpg17145.

[0006] Patent No. 6670824 discloses Mo(=NR)2(OR)2.

[0007] Patent No. 7171916 is It discloses JPEG2025020638000003.jpg37123JPEG2025020638000004.jpg29117JPEG2025020638000005.jpg27118.

[0008] Chem Mater. (2007), 19, 263-269 discloses Mo(NR)2(NR'2)2.

[0009] J. Mat. Res. 9(7), 1994, 1622-1624 discloses Mo(NtBu)2(NHtBu)2. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Patent Publication No. 2000-119045 [Patent Document 2] Special table 2022-524041 [Patent Document 3] Patent No. 5913663 [Patent Document 4] Patent No. 6670824 [Patent Document 5] Patent No. 7171916 [Non-patent literature]

[0011] [Non-Patent Document 1] Chem Mater.(2007),19,263-269 [Non-Patent Document 2] J. Mat. Res. 9(7), 1994, 1622-1624 [Non-Patent Document 3] Dalton Trans.,2003,4457-4465 Summary of the Invention [Problem to be solved by the invention]

[0012] Previously proposed Group VI transition metal precursors have been unsatisfactory. The reasons for this are thought to be as follows: Mo has a high affinity for C, N, or O, so it was difficult to obtain a high-quality, conformal Mo-containing film. The Mo precursor was a solid (25°C (1 atm)). There were cases where transportation was difficult during the transportation process (the process of transporting to the deposition process of the Mo-containing film). For example, it was necessary to heat and keep the transportation pipe warm. Otherwise, the precursor would adhere and accumulate inside the transportation pipe, which could cause the inside of the transportation pipe to become clogged. Transportation was hindered. At the large-scale factory stage, there were cases where heating and heat-keeping equipment was required. It was expensive.

[0013] Molybdenum carbonyl compounds (e.g., Mo(CO)6) are solids (at 25 °C and 1 atm). Transport of solids is difficult. There is a risk that Mo may act as a catalyst for CO dissociation, resulting in the incorporation of large amounts of carbon into the growing Mo-containing film.

[0014] Molybdenum halide compounds (e.g., MoCl5) are also solids (at 25°C (1 atm)). They are difficult to transport. Cl from MoCl5 may cause etching of the Mo-containing film being grown.

[0015] Imido / alkoxide molybdenum compounds (e.g., Mo(=NtBu)2(OiPr)2) are also solids (at 25°C (1 atm)). Transportation is difficult.

[0016] Oxo / alkoxide compounds (e.g., Mo(=O)2(OtBu)2) are liquids (25°C (1 atm)). However, such compounds undergo clustering due to traces of moisture. Long-term stable storage is difficult. Furthermore, there is a risk of large amounts of particles being mixed into the Mo-containing film during growth.

[0017] For these reasons, the problem to be solved by the present invention is to provide a Group VI transition metal precursor capable of solving the above problems, for example, to provide a compound capable of forming a high-quality (e.g., low-impurity) and highly conformal Group VI transition metal-based film that has excellent storage stability and can be easily transported to a film-forming chamber when the film is formed by CVD or ALD. [Means for solving the problem]

[0018] The present invention relates to It is liquid at 25°C (1 atm), Represented by the following formula (I): Propose a new compound. Formula (I) JPEG2025020638000006.jpg30115 (In formula (I), M is a group VI element. NR 1 does not have Si. R 1 ,R 2 ,R 3 R is an alkyl group having 1 to 10 carbon atoms. 2 ≠R 3 It is.)

[0019] The present invention relates to A film-forming material comprising: The material is It is liquid at 25°C (1 atm), The compound represented by the above formula (I) is A film-forming material is proposed.

[0020] The present invention relates to a film forming method, in which a compound represented by the above formula (I), which is liquid at 25° C. (1 atm), is transported to a film forming chamber and decomposed to form a Group VI element-based film on a substrate. A film formation method is proposed.

[0021] In the above proposed invention, M is Mo, for example. In the above proposed invention, M is W, for example.

[0022] In the above proposed invention,1 is preferably an alkyl group having a branched chain.

[0023] In the above proposed invention, 1 is preferably an alkyl group having a carbon number of 3 to 7. More preferably, it is an alkyl group having a carbon number of 4 or 5. Particularly preferably, it is a tert-butyl group.

[0024] In the above proposed invention, 2 was preferably an alkyl group having a straight or branched chain.

[0025] In the above proposed invention, 2 is preferably an alkyl group having 2 to 10 carbon atoms, more preferably an alkyl group having 2 to 5 carbon atoms, and particularly preferably an ethyl group or an isopropyl group.

[0026] In the above proposed invention, 3 was preferably an alkyl group having a straight or branched chain.

[0027] In the above proposed invention, 3 is preferably an alkyl group having 2 to 10 carbon atoms, more preferably an alkyl group having 2 to 5 carbon atoms, and particularly preferably a tert-amyl group.

[0028] In the invention of the film formation method proposed above, for example, CVD or ALD is used. Effect of the Invention

[0029] The compound of the present invention (a Group VI transition metal organic compound) is liquid at 25°C (1 atm). It has a high vapor pressure. It can be transported smoothly to the film formation chamber without heating or keeping it warm. The film formation cost is low.

[0030] The compound of the present invention (a Group VI transition metal organic compound) was stable and had good storage stability. Clustering due to traces of moisture was unlikely to occur. A high-quality, conformal film could be formed.

[0031] The films obtained by CVD or ALD had few impurities and were of high quality. [Brief description of the drawings]

[0032] [Figure 1] NMR chart of (tBuN)2Mo(OiPr)2 [Diagram 2] Thermogravimetric analysis (TG-DTA) diagram of (tBuN)2Mo(OiPr)2 [Diagram 3] NMR chart of (tBuN)2Mo(OtBu)2 [Figure 4] NMR chart of (tBuN)2Mo(OiPr)(OtAm) [Diagram 5] Thermogravimetric analysis (TG-DTA) diagram of (tBuN)2Mo(OiPr)(OtAm) DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] Embodiments of the present invention are described below.

[0034] The first invention is a novel compound. The compound is liquid at 25° C. (1 atm). The compound is represented by the formula (I). In the formula (I), M is a Group VI element. In particular, it is a metal element. For example, Mo or W. NR 1 does not have Si. R 1 ,R 2 ,R 3 R is an alkyl group having 1 to 10 carbon atoms. 2 ≠R 3 It is.

[0035] The alkyl group R 1The number of carbon atoms in the alkyl group R is preferably 3 or more, more preferably 7 or less, and even more preferably 4 or 5. Among the alkyl groups, branched alkyl groups are preferred. Preferred alkyl groups R 1 The most preferred group was the tert-butyl group (tBu) or the tert-amyl group (tAm). The most preferred group was the tert-butyl group (tBu). 1 is SiHn(CH3) 3-n (n is not 0, 1, or 2). In other words, it is not an alkyl group containing silicon.

[0036] The alkyl group R 2 The carbon number of R is preferably 2 or more, more preferably 7 or less, and even more preferably 5 or less. 2 is preferably an alkyl group having a straight chain or a branched chain. 2 The most preferred groups were ethyl (Et), iso-propyl (iPr), n-propyl (nPr), n-butyl (nBu), tert-butyl (tBu), n-pentyl (nPen), and tert-amyl (tAm). The most preferred groups were ethyl (Et) and iso-propyl (iPr). Among them, the most preferred group was iso-propyl (iPr).

[0037] The alkyl group R 3 The number of carbon atoms in the alkyl group R is preferably 2 or more, more preferably 7 or less, and even more preferably 5 or less. 3 is preferably a linear or branched alkyl group, more preferably a branched alkyl group. 3 The most preferred alkyl groups R are ethyl (Et), isopropyl (iPr), tert-butyl (tBu), and tert-amyl (tAm). 3 was a tert-amyl group (tAm).

[0038] R 1 ,R 2 ,R 3The reason why is specified as above is as follows. The compounds not falling within the above-specified group do not satisfy the condition [liquid] at 25°C (1 atm). The condition [liquid] is an important requirement when transporting to a film-forming chamber. The above-specified compounds could be synthesized through well-known reactions.

[0039] Examples of the compound represented by the above formula (I) are shown below. JPEG2025020638000007.jpg153138JPEG2025020638000008.jpg139138JPEG2025020638000009.jpg56138

[0040] The second invention is a film-forming material. The material is the compound. Or, the material contains the compound as one component. The film is a film of a Group VI metal element. For example, it is a metallic molybdenum film. Or, it is a metallic tungsten film. The film is a film containing a Group VI metal element. For example, it is a Group VI metal oxide film. For example, it is a molybdenum oxide film. Or, it is a tungsten oxide film. Or, it is a Group VI metal nitride film. For example, it is a molybdenum nitride film. Or, it is a tungsten nitride film. Or, it is a Group VI metal sulfide film. However, it is not limited to these.

[0041] The third invention is a film formation method. In the method, the material is transported to a film formation chamber and decomposed to form a film of a VI group element on a substrate. For example, CVD or ALD is used to form the film. In the present invention, thermal CVD, low temperature CVD, pulsed CVD (PCVD), cyclic CVD (CCVD), plasma enhanced CVD (PECVD), metal organic CVD (MOCVD), chemical vapor deposition (CVD), high density PECVD, photon assisted CVD, plasma-photon assisted CVD (PPECVD), low pressure CVD (LPCVD), sub-atmospheric pressure CVD (SACVD), atmospheric pressure CVD (APCVD), hot filament CVD, hot wire CVD (HWCVD, also known as cat-CVD, where a hot wire acts as the energy source for the deposition process), radicals incorporated CVD, etc. are types of CVD. In the present invention, thermal ALD, plasma enhanced ALD (PEALD), spatial isolation ALD, hot wire ALD (HWALD), radicals incorporated ALD, etc. are types of ALD. Alternatively, a process similar to CVD or ALD is employed. Such a similar process is also included in the CVD or ALD of the present invention. The substrate on which the VI group element-containing film is formed may be any type. The substrate may be any material on which a film can be formed. The substrate may be any suitable substrate used in, for example, semiconductor, photovoltaic cell, flat panel, or LCD-TFT device manufacturing. Examples of the substrate include wafers of silicon, silica, glass, GaAs, etc. Examples of the wafer include a silicon layer (crystalline, amorphous, porous, etc.), a silicon oxide layer, a silicon nitride layer, a silicon oxynitride layer, a carbon-doped silicon oxide (SiCOH) layer, or a combination thereof. Examples of the wafer may include a copper layer or a noble metal layer (e.g., platinum, palladium, rhodium, or gold). The wafer may have a surface having a metal, metal oxide, metal nitride, silicon, silicon oxide, or silicon nitride film. Of course, the wafer is not limited to these.

[0042] The compounds of the present invention may be referred to as Group VI transition metal organic compounds, Group VI transition metal precursor compounds, metal complexes or complexes, simply precursors, or simply compounds.

[0043] The following description is merely a preferred exemplary embodiment. It is not intended to limit the scope, applicability, or configuration of the present invention. It is merely provided to those skilled in the art with a description to implement or enable the preferred exemplary embodiment of the present invention. Various changes can be made in the function and arrangement of elements without departing from the spirit and scope of the present invention as defined in the claims.

[0044] The precursors preferably used in the deposition (CVD, ALD) of Group VI transition metal films are compounds that are liquid at 25°C (1 atm) and have the structure of the above general formula (I). M is Mo or W. 1 ,R 2 ,R 3 is a straight-chain or branched-chain alkyl group having 1 to 10 carbon atoms. Examples of such groups include a methyl group (Me), an ethyl group (Et), an n-propyl group (nPr), an isopropyl group (iPr), an n-butyl group (nBu), an isobutyl group (iBu), a sec-butyl group (sBu), a tert-butyl group (tBu), and a tert-amyl group (tAm). Among the above groups, preferred R 1 is an alkyl group having a branched chain. Among them, tert-butyl group (tBu) is preferable. 2 was a linear or branched alkyl group. Among them, Et and iPr were preferred. 3 was an alkyl group having a straight or branched chain. Among them, tAm was the most important.

[0045] In the field of metal-containing film deposition, the temperature of the substrate is an important process variable. Typical substrate temperatures are about 150°C to about 550°C. Higher substrate temperatures generally lead to higher deposition rates. It is therefore important to select precursors that can be deposited at higher temperatures. It is also important that the precursors are stable during storage, i.e., have good storage stability.

[0046] The precursor is preferably liquid during use (for example, at normal temperature or room temperature (specifically, 25° C. (1 atm))). When the precursor is liquid, it has a high vapor pressure and is easy to handle. In particular, there is no need to heat and keep the transport pipe warm during transportation. The precursor can be transported smoothly without heating and keeping the transport pipe warm. If the precursor is solid, there is a risk that the precursor will adhere and accumulate on the inner wall of the transport pipe. This will cause the transport pipe to become clogged, and smooth transportation will not be possible.

[0047] A carrier gas is generally used to transport the precursor to the deposition chamber. For example, this is done by bubbling a carrier gas (e.g., an inert gas) into the precursor-containing solution. Bubbling a gas into a liquid is an effective means of providing a longer contact time between the gas and the liquid and a larger contact area between the gas and the liquid. This is aimed at achieving a gas flow saturated with the vaporized precursor. Achieving a saturated carrier gas increases the transport rate of the precursor. This is advantageous for the operation of the deposition process of metal-containing films. Even when transporting the precursor in this manner, it is preferable that the precursor is a liquid.

[0048] Incidentally, in the above-mentioned Patent Document 4 (JP Patent No. 6670824), in Synthesis Example 1, (tBuN)2Mo(OiPr)2 is disclosed as a golden liquid. However, this description is incorrect, and it is a yellow solid with a melting point between 50 and 60°C. In Synthesis Example 2, (tBuN)2Mo(OtBu)2 is disclosed as a yellow oil. However, this description is incorrect, and it is a yellow solid with a melting point between 35 and 40°C. In Synthesis Example 3, (tBuN)2Mo(OEt)2 is disclosed as a brown wax. The wax also includes so-called liquid wax. However, this compound was not liquid. That is, it was solid at 25°C (1 atm).

[0049] The present invention will be described in detail below. The following examples are merely examples of the present invention. The present invention is not limited to the following examples. In other words, the present invention also includes modifications and applications that do not significantly impair the features of the present invention.

[0050] [Comparative synthesis example 1: (tBuN)2Mo(OiPr)2] The synthesis was carried out under a nitrogen atmosphere. 5.5 g of (tBuN)2Mo(NEt2)2 and 100 ml of hexane were added to a vessel. The vessel was cooled to a temperature of -20°C to -50°C. During this time, stirring was carried out in the vessel. 2.0 g of iPrOH was gradually added to the mixture. After addition, cooling of the vessel was stopped. The temperature in the vessel gradually returned to room temperature. The solution at room temperature was stirred. After this, the solvent was removed from the obtained solution by vacuum distillation. The obtained crude product was purified by vacuum distillation. A yellow liquid was obtained. This yellow liquid changed to a yellow solid. This substance (compound) was solid at 25°C (1 atm). The melting point was about 60°C. The NMR spectrum of this compound (yellow solid) is shown in Figure 1. Figure 1 shows that the compound is (tBuN)2Mo(OiPr)2. The thermogravimetric analysis (TG-DTA) of the compound (yellow solid) is shown in Figure 2. Figure 2 shows that the weight loss occurred in multiple stages (three stages). Therefore, the compound of Comparative Synthesis Example 1 is not preferable as a film-forming material.

[0051] [Comparative synthesis example 2: (tBuN)2Mo(OtBu)2] The synthesis was carried out under a nitrogen atmosphere. 7.4 g of [(tBuN)2MoCl2(tBuNH2)]2 and 100 ml of toluene were added to a vessel. The vessel was cooled to a temperature of -20°C to -50°C. During this time, stirring was carried out in the vessel. 3.8 g of tBuONa was gradually added to the mixture. After addition, cooling of the vessel was stopped. The temperature in the vessel gradually returned to room temperature. The solution at room temperature was stirred. After this, the obtained solution was subjected to a filtration process. The solvent was removed by vacuum distillation. The obtained crude product was purified by vacuum distillation. A yellow liquid was obtained. This yellow liquid changed to a yellow solid. This substance (compound) was solid at 25°C (1 atm). The melting point was about 40°C. The NMR spectrum of this compound (yellow solid) is shown in Figure 3. Figure 3 shows that the compound is (tBuN)2Mo(OtBu)2. Therefore, the compound of Comparative Synthesis Example 2 is not preferable as a film-forming material.

[0052] [Example 1: (tBuN)2Mo(OiPr)(OtAm)] The reaction was carried out under a nitrogen atmosphere. 1.5 g of (tBuN)2Mo(OiPr)2 and 30 ml of hexane were added to the vessel. The vessel was cooled to a temperature of -20°C to -50°C. During this time, stirring was performed in the vessel. 1.7 g of (tBuN)2Mo(OtAm)2 was gradually added to the mixture. After addition, cooling of the vessel was stopped. The temperature in the vessel gradually returned to room temperature. The solution at room temperature was stirred. After this, the solvent was removed from the obtained solution by vacuum distillation. The obtained crude product was purified by vacuum distillation. A yellow liquid was obtained. This yellow liquid did not change to a solid. It remained liquid. The boiling point of this compound (yellow liquid) was 59°C (13 Pa). The compound of the present invention is liquid at room temperature, unlike the compounds of Comparative Synthesis Examples 1 and 2, has a high vapor pressure, and is highly volatile. The NMR spectrum of the compound (yellow liquid) is shown in Figure 4. Figure 4 shows that the compound is (tBuN)2Mo(OiPr)(OtAm). The thermogravimetric analysis (TG-DTA) of the compound (yellow liquid) is shown in Figure 5. Figure 5 shows a single-stage weight loss curve. It is clear that the compound has excellent thermal stability and good vaporization. This compound was used to form films by CVD (and ALD). Each of the films obtained was a metallic Mo film with few impurities.

Claims

1. A film-forming material comprising: The material is It is liquid at 25°C (1 atm), A compound represented by the following formula (I): is Film-forming material. Formula (I) (In formula (I), M is a Group VI element. NR １ does not have Si. １ , R ２ , R ３ is an alkyl group having 1 to 10 carbon atoms. ２ ≠R ３ It is.)

2. The R １ is an alkyl group having 3 to 7 carbon atoms The film-forming material of claim 1.

3. The R １ is an alkyl group having 4 or 5 carbon atoms The film-forming material of claim 2.

4. The R １ is a tert-butyl group The film-forming material of claim 3.

5. The R １ is a branched alkyl group The film-forming material of claim 1.

6. The R ２ is an alkyl group having 2 to 5 carbon atoms The film-forming material of claim 1.

7. The R ２ is an ethyl group or an iso-propyl group The film-forming material of claim 1.

8. The R ２ is a straight or branched chain alkyl group The film-forming material of claim 1.

9. The R ３ is an alkyl group having 2 to 5 carbon atoms The film-forming material of claim 1.

10. The R ３ is a tert-amyl group The film-forming material of claim 9.

11. The R ３ is a straight or branched chain alkyl group The film-forming material of claim 1.

12. The M is Mo. The film-forming material of claim 1.

13. The M is W. The film-forming material of claim 1.

14. A film-forming material according to any one of claims 1 to 13 is transported to a film-forming chamber and decomposed to form a Group VI element film on a substrate. Film formation method.

15. The film formation method uses CVD. The film forming method according to claim 14.

16. The film formation method uses ALD. The film forming method according to claim 14.

17. It is liquid at 25°C (1 atm), Represented by the following formula (I): New compound. Formula (I) (In formula (I), M is a Group VI element. NR １ does not have Si. １ , R ２ is an alkyl group having 1 to 10 carbon atoms, R ３ is a tert-amyl group. ２ ≠R ３ It is.)

18. The R １ is a tert-butyl group 18. The novel compound of claim 17.

19. The R ２ is an ethyl group or an iso-propyl group 18. The novel compound of claim 17.

20. The M is Mo or W.

18. The novel compound of claim 17.

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