METHOD FOR FORMING METAL NITRIDE THIN FILM

Abstract

According to one embodiment of the present invention, a method for forming a metal nitride thin film includes a deposition step of supplying a metal precursor to a substrate to selectively deposit it on a surface of the substrate; a halogen treatment step of supplying a halogen gas to the substrate to form a metal halide compound on the surface of the substrate; and a nitridation step of supplying a nitrogen source to the substrate to react with the metal halide compound to form a metal nitride.

Description

[Technical field]

[0001] The present invention relates to a method for forming a metal nitride thin film, and more particularly to a method for forming a metal nitride thin film using a halogen gas. [Background technology]

[0002] Niobium nitride (NbN x , where x is about 1), have been widely used in various technical fields.

[0003] Traditionally, these nitrides have been applied as hard coatings and decorative coatings, but in the last decades they have increasingly been used as diffusion barriers and glue layers in microelectronic devices [Applied Surface Science 120 (1997) 199-212].

[0004] For example, NbCl5 was investigated as a niobium source for the atomic layer epitaxial growth of NbN, but this method required Zn as a reducing agent [Applied Surface Science 82 / 83 (1994) 468-474]. x Films have also been deposited by atomic layer deposition using NbCl5 and NH3 [Thin Solid Films 491 (2005) 235-241]. The chlorine content showed a strong temperature dependence such that films deposited at 500°C were nearly chlorine-free, whereas the chlorine content was 8% when the deposition temperature was as low as 250°C (ibid.). The high melting point of NbCl5 also makes the precursor difficult to use in evaporation processes.

[0005] Gust et al. disclose the synthesis, structure and characterization of niobium and tantalum imide complexes bearing pyrazolate ligands and their potential use for the growth of tantalum nitride films by CVD. Elorriaga et al. disclose unsymmetrical niobium guanidinates as intermediates in the catalytic guanylation of amines (Dalton Transactions, 2013, Vol. 42, Issue 23 pp. 8223-8230).

[0006] Tomson et al. have disclosed the synthesis and reactivity of cationic Nb and Ta monomethyl complexes [(BDI)MeM(NtBu)][X] (BDI = 2,6-iPr2C6H3-NC(Me)CH-C(Me)-N(2,6-iPr2C6H3); X = MeB(C6F5)3 or B(C6F5)4) (Dalton Transactions 2011 Vol. 40, Issue 30, pp. 7718-7729).

[0007] DE 102006037955 (Starck) discloses tantalum and niobium compounds having the formula R4R5R6M(R1NNR2R3)2, where M is Ta or Nb; R1-R3 = C1-12 alkyl, C5-12 cycloalkyl, C6-10 aryl, alkenyl, C1-4 triorganosilyl; R4-R6 = halo, (cyclo)alkoxy, aryloxy, siloxy, BH4, allyl, indenyl, benzyl, cyclopentadienyl, CH2SiMe3, silylamide, amido or imino.

[0008] Maestre et al. disclose the reaction of Group 5 metal monocyclopentadienyl complexes with cyclopentadienyl-silyl-amido titanium compounds to form NbCp(NH(CH2)2-NH2)Cl3 and NbCpCl2(N-(CH2)2-N).

[0009] There remains a need for new liquid or low melting (<50°C at standard pressure) and highly thermally stable group V-containing precursor molecules suitable for vapor film deposition at high temperatures with thickness and composition control. Also, physical vapor deposition techniques such as sputtering have been used to form fine metal wiring, but these techniques have poor step coverage.

[0010] In recent years, with the trend toward ultra-integration and ultra-thin films in semiconductor devices, chemical vapor deposition (CVD) has been developed as a thin film deposition technology with uniform deposition characteristics and step coverage. However, with chemical vapor deposition, all materials required for thin film formation are supplied simultaneously into the process chamber, making it difficult to form a film with the desired composition ratio and physical properties, and the process proceeds at high temperatures, which degrades the electrical characteristics of the device and reduces the storage capacity. To solve these problems, atomic layer deposition (ALD) has been developed, which supplies process gases independently rather than continuously.

[0011] Detailed Description of the Invention technical challenges An object of the present invention is to provide a method for effectively forming a metal nitride thin film.

[0012] Other objects of the present invention will become more apparent from the following detailed description of the invention and the accompanying drawings.

[0013] Problem solving means According to one embodiment of the invention, a method for forming a metal nitride thin film includes a deposition step of supplying a metal precursor to a substrate and depositing the metal precursor on a surface of the substrate; a halogen treatment step of supplying a halogen gas to the substrate to form a metal halide on the surface of the substrate; and a nitridation step of supplying a nitrogen source to the substrate to react with the metal halide to form a metal nitride, The metal precursor ,M (NR1R2)2(NR3)R4 in can be, M is V, Nb, T A It is one of them. , R 1, R2, R3, and R4 are hydrocarbons.

[0018] In the above M(NR1R2)2(NR3)R4 ,R 1, R2, R3, and R4 are each independently one of linear hydrocarbons, branched hydrocarbons, or cyclic hydrocarbons having 1 to 10 carbon atoms, which may be the same or different, and are represented by the following <chemical formula 3>. [ka]

[0019] The metal precursor is supplied with a carrier gas, and the carrier gas Is A The gas may be one or more of the inert gases including argon (Ar) and helium (He).

[0020] The halogen gas may be one or more of X2 and HX.

[0021] The nitrogen source is selected from the group consisting of NH3, NHR2 (R is at least one of a C1-C5 linear alkyl group, a branched alkyl group, and an aromatic alkyl group), NH2R (R is at least one of a C1-C5 linear alkyl group, a branched alkyl group, and an aromatic alkyl group), NR3 (R is at least one of a C1-C5 linear alkyl group, a branched alkyl group, and an aromatic alkyl group), hydrazine (H4N2), R-hydrazine (R is at least one of a C1-C5 linear alkyl group, a branched alkyl group, and an aromatic alkyl group), and H2 / N 2 mixture The plasma may be one or more of plasma, N2 plasma, and NH3 plasma.

[0022] The deposition step, the halogen treatment step, and the nitriding step can each be carried out at a temperature of 250 to 600°C.

[0023] The depositing step, the halogen treatment step, and the nitriding step form one cycle, which can be repeated.

[0024] Effect of the Invention According to one embodiment of the present invention, it has been confirmed that the metal precursor is suitable for depositing metal nitrides (e.g., niobium thin films), and since the metal precursor has high thermal stability that does not deteriorate its properties even when heated continuously and high vapor pressure, it can be usefully applied to semiconductor manufacturing processes that deposit metal nitride thin films using Metal Organic Chemical Vapor Deposition (MOCVD) and Atomic Layer Deposition (ALD).

[0025] It is also found that the method of forming a metal nitride thin film using a metal precursor can be advantageously applied to the formation of a metal nitride thin film free of carbon and halogen impurities. [Brief description of the drawings]

[0026] [Figure 1] 1 is a flow chart illustrating a method for forming a metal nitride thin film according to an embodiment of the present invention. [Diagram 2] 1A to 1C are diagrams illustrating a process for forming a metal nitride thin film according to an embodiment of the present invention. [Diagram 3] 1A to 1C are diagrams illustrating a process for forming a metal nitride thin film according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the attached Figs. 1 and 3. The embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. The embodiments are provided to explain the present invention in more detail to those having ordinary skill in the art to which the invention pertains. Therefore, the shape of each element shown in the drawings may be exaggerated to emphasize a clearer description.

[0028] First, the conventionally used precursor NbCl5 is a solid, which causes clogging of the piping in the deposition equipment, making it difficult to sublimate it into a gas and transport a constant amount to the deposition chamber. In addition, other organometallic precursors have a high carbon content, which causes problems with impurities affecting the film quality.

[0029] The method for forming a metal (V) nitride thin film described below is a method for forming a thin film on the surface of a substrate via atomic layer deposition (ALD) or metalorganic chemical vapor deposition. The following general formula shows a reaction scheme for forming a thin film free of carbon and halogen impurities, even when using a liquid precursor, compared to when using existing solid precursors.

[0030] FIG. 1 is a flow chart illustrating a method for forming a metal nitride thin film according to an embodiment of the present invention, and FIGS. 2 and 3 are views illustrating a process for forming a metal nitride thin film according to an embodiment of the present invention. [ka] M=V, Nb, Ta, W (the oxidation state of M is (I to V) or a mixed state). X=One of the 17 groups on the periodic table that includes F, Cl, Br, and I. R1 and R2 are each independently one of a straight-chain alkyl group, a branched alkyl group, or a cyclic alkyl group having 1 to 10 carbon atoms, and may be the same or different. 1≦n≦4 1≦a≦4 1≦b≦5

[0031] MX n (NR1R2) 5-n is a metal (V) precursor for forming a metal nitride thin film. As shown in Figures 1 to 3 (in the case of M=Nb), a substrate is supplied into a chamber ("Substrate Supply Step"), and the metal precursor is supplied to the substrate in the chamber and selectively deposited on the surface of the substrate ("Deposition Step"). The metal precursor can be supplied into the chamber via a liquid delivery system, at which point it can be vaporized at an appropriate temperature and delivered in a uniform gaseous state.

[0032] In addition, various supply methods can be applied, including a bubbling method, a vapor phase mass flow controller, direct liquid injection (DLI), and a liquid transfer method in which the precursor compound is dissolved in an organic solvent and transferred. As a carrier gas for supplying the metal precursor, one or a mixture of two or more of nitrogen (N2), argon (Ar), helium (He), and hydrogen (H2) can be used.

[0033] Then, a halogen gas (X2 or HX) is supplied to the substrate in the chamber, and the halogen gas can form a metal halide compound on the surface of the substrate while simultaneously removing impurities, for example in the form of R-Cl (halogen treatment process).

[0034] Then, a nitrogen source is supplied to the substrate to remove reaction by-products and unreacted materials, and at the same time, reacts with the metal halide to form a metal nitride ("nitridation step"). The nitrogen source can be one or more of NH3, NHR2 (R is at least one of C1-C5 linear alkyl groups, branched alkyl groups, and aromatic alkyl groups), NHR (R is at least one of C1-C5 linear alkyl groups, branched alkyl groups, and aromatic alkyl groups), NR3 (R is at least one of C1-C5 linear alkyl groups, branched alkyl groups, and aromatic alkyl groups), hydrazine (H4N2), R-hydrazine (R is at least one of C1-C5 linear alkyl groups, branched alkyl groups, and aromatic alkyl groups), H2 / N2 mixed plasma, and NH3 plasma, and impurities can be removed with (R3N)-HCl salt (R = C1-5 linear alkyl groups, branched alkyl groups, and cyclic alkyl groups).

[0035] Meanwhile, the deposition step, the halogen treatment step, and the nitriding step can each be carried out at 250 to 600° C. Furthermore, the deposition step, the halogen treatment step, and the nitriding step form one cycle, and the cycle can be repeated several times. [ka] M=V, Nb, Ta, W (the oxidation state of M is (I to V) or a mixed state). X=One of the 17 groups on the periodic table that includes F, Cl, Br, and I. R1, R2, and R3 are each independently one of a linear alkyl group, a branched alkyl group, or a cyclic alkyl group having 1 to 10 carbon atoms, and may be the same or different. 1≦n≦4 1≦a≦4 1≦b≦5

[0036] The MX(NR1R2)2NR3 is a metal (V) precursor for forming a metal nitride thin film and is represented by the following <Chemical Formula 1>. [ka] [ka] M=V, Nb, Ta, W (the oxidation state of M is (I to V) or a mixed state). X=One of the 17 groups on the periodic table that includes F, Cl, Br, and I. R1, R2, and R3 are each independently one of a straight-chain alkyl group, a branched alkyl group, or a cyclic alkyl group having 1 to 10 carbon atoms, and may be the same or different. 1≦n≦4 1≦a≦4 1≦b≦5

[0037] MX2(NR1R2)NR3 is a metal (V) precursor for forming a metal nitride thin film and is represented by the following <Chemical Formula 2>. [ka] [ka] M=V, Nb, Ta, W (the oxidation state of M is (I to V) or a mixed state). X=One of the 17 groups on the periodic table that includes F, Cl, Br, and I. R1, R2, R3, and R4 are each independently one of a straight-chain linear alkyl group, a branched alkyl group, or a cyclic alkyl group having 1 to 10 carbon atoms, and may be the same or different. 1≦n≦4 1≦a≦4 1≦b≦5

[0038] The M(NR1R2)2(NR3)R4 is a metal (V) precursor for forming a metal nitride thin film and is represented by the following <Chemical Formula 3>. [ka]

[0039] Although the present invention has been described in detail with reference to the embodiments, other embodiments are possible, and therefore the technical spirit and scope of the claims set forth below are not limited to the embodiments. [Industrial Applicability]

[0040] The present invention is applicable to various types of semiconductor manufacturing methods.

Claims

1. 1. A method for forming a metal nitride thin film, comprising: a depositing step of delivering a metal precursor to a substrate and depositing the metal precursor on a surface of the substrate; a halogen treatment step of supplying a halogen gas to the substrate to form a metal halide on the surface of the substrate; and providing a nitrogen source to the substrate to react with the metal halide to form a metal nitride; The metal precursor is M(NR 1 R 2 ) 2 (NR 3 ) R4, M is one of V, Nb, and Ta; R 1 , R 2 , R 3 , and R 4 is a hydrocarbon, A method for forming metal nitride thin films.

2. The metal nitride is M a N b 2. The method of claim 1, wherein M is one of V, Nb, and Ta, 1≦a≦4, and 1≦b≦5.

3. Said M(NR 1 R 2 ) 2 (NR 3 ) R 4 In the above, R 1 , R 2 , R 3 , R 4 wherein each of the groups independently represents one of a linear hydrocarbon, a branched hydrocarbon, and a cyclic hydrocarbon having 1 to 10 carbon atoms, is the same or different from each other, and is represented by the following formula 3:

4. 4. The method for forming a metal nitride thin film according to claim 1, wherein the metal precursor is supplied with a carrier gas, the carrier gas being at least one of an inert gas including argon (Ar) and helium (He).

5. The halogen gas is X 2 4. The method of claim 1, wherein the metal nitride thin film is at least one of H, HX.

6. The nitrogen source is NH 3 , N.H.R. 2 (R is C 1 ~C 5 At least one of a linear alkyl group, a branched alkyl group, or an aromatic alkyl group, NH 2 R (R is C 1 ~C 5 At least one of a linear alkyl group, a branched alkyl group, or an aromatic alkyl group, NR 3 (R is C 1 ~C 5 At least one of the linear alkyl group, branched alkyl group, or aromatic alkyl group), hydrazine (H 4 N 2 ), R-hydrazine (R is C 1 ~C 5 At least one of a linear alkyl group, a branched alkyl group, or an aromatic alkyl group, H 2 / N 2 Mixed plasma, N 2 Plasma or NH 3 4. The method for forming a metal nitride thin film according to claim 1, further comprising one or more of: a plasma;

7. 4. The method for forming a metal nitride thin film according to claim 1, wherein the depositing step, the halogen treatment step, and the nitriding step are each carried out at a temperature of 250 to 600.degree.

8. 4. The method of claim 1, wherein the depositing step, the halogen treatment step, and the nitriding step form a cycle, and the cycle is repeated.

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