Novel precursor for forming metal-containing thin film, method for forming metal-containing thin film using same, and semiconductor device including thin film

Abstract

The present invention relates to a novel precursor for forming a metal-containing thin film, a method for forming a thin film using same, and a device including the thin film and, more specifically, to a novel precursor for forming a metal-containing thin film to allow high deposition temperatures and have low viscosity properties, a method for forming a thin film using same, and a device including the thin film.

Description

A novel precursor for forming a metal-containing thin film, a method for forming a metal-containing thin film using the same, and a semiconductor device including the thin film

[0001] The present invention relates to a novel precursor for forming a metal-containing thin film, a method for forming a metal-containing thin film using the same, and a semiconductor device including said thin film. More specifically, the invention relates to a novel precursor for forming a metal-containing thin film having high deposition temperature and low viscosity characteristics, a method for forming a metal-containing thin film using the same, and a semiconductor device including said thin film.

[0002] As integration density improves through the miniaturization of semiconductor lines, the space allowed for capacitor structure implementation is becoming limited by linewidth; consequently, conventional silicon-based dielectrics are facing limitations in the manufacturing methods for semiconductor devices used to implement capacitor structures. Furthermore, as silicon-based dielectrics are being replaced and semiconductor device performance improves, thin films utilizing high-dielectric materials are being applied. However, using materials with excessively high dielectric constants presents a problem in that the energy bandgap decreases, while leakage current actually increases.

[0003] One of the solutions to address these problems is the need for a technology to form high-quality thin films, and to this end, it is necessary to optimize the precursors used in thin film formation.

[0004] Accordingly, as a method to optimize precursors for forming metal-containing thin films, various precursors capable of improving dielectric constant and leakage current characteristics have been proposed; however, these precursors are generally solid or low-volatility liquid phases, and various problems exist, such as limitations in securing the low viscosity characteristics required for forming high-quality thin films. Therefore, to optimize precursors for thin film formation, it is necessary to develop precursors that satisfy various requirements for high-quality film formation, such as high volatility, thermal stability, and low viscosity characteristics.

[0005] The present invention has been devised in consideration of the prior art described above, and aims to provide a precursor comprising a novel metal-containing thin film compound that satisfies the characteristics of low viscosity, high heat resistance, high volatility, and being in a liquid state at room temperature.

[0006] In addition, the present invention aims to provide a precursor comprising a novel metal-containing thin film compound capable of forming a high-quality thin film even under various deposition conditions, such as high-temperature deposition conditions, based on improved physical properties.

[0007] In addition, the present invention aims to provide a method for forming a metal-containing thin film capable of forming a high-quality metal-containing thin film by using a precursor comprising a novel compound for a metal-containing thin film, and a semiconductor device comprising said thin film.

[0008] The objectives of the present invention are not limited to those mentioned above, and other objectives and advantages of the present invention not mentioned may be understood from the following description and will be more clearly understood by the embodiments of the present invention. Furthermore, it will be readily apparent that the objectives and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0009] To achieve the above objective, according to a first embodiment of the present invention, a precursor for forming a metal-containing thin film comprising a compound represented by the following chemical formula 1 may be provided.

[0010] [Chemical Formula 1]

[0011] In the above chemical formula 1, M represents bismuth (Bi), N represents nitrogen, R1 to R4 may be identical or different from each other, and each may be independently selected from hydrogen, a C1-C5 straight-chain alkyl group, a C3-C5 branched alkyl group, a C3-C8 cyclic alkyl group, and a C2-C6 alkenyl group, and n may be an integer from 1 to 5.

[0012] According to a second aspect of the present invention, a method for forming a metal-containing thin film can be provided, comprising: a first step of preparing a substrate in a reactor; a second step of forming a metal-containing thin film by depositing a precursor for forming a metal-containing thin film according to a first aspect of the present invention on the surface of the substrate; and a third step of reacting the metal-containing thin film with a reactive gas.

[0013] According to a third aspect of the present invention, a semiconductor device may be provided comprising a metal-containing thin film formed by depositing a precursor for forming a metal-containing thin film according to a first aspect of the present invention on the surface of a substrate.

[0014] Due to the chemical properties of the novel metal-containing thin film compound according to the present invention, such as low viscosity, high volatility, high heat resistance, and a room-temperature liquid form, a high-quality thin film can be formed when used as a precursor.

[0015] In addition, the novel metal-containing thin film compound according to the present invention has the advantage of enabling the formation of high-quality thin films even under high-temperature deposition conditions.

[0016] In addition to the effects described above, the effects of the present invention are described together with the details for implementing the invention below.

[0017] FIG. 1 is of 3-dimethylaminopropyldimethylbismuth, a compound prepared in Synthesis Example 1 of the present invention. 1 This is a graph of the H-NMR analysis results.

[0018] Figure 2 is a graph of the GC-MS analysis results of 3-dimethylaminopropyldimethylbismuth, a compound prepared in Synthesis Example 1 of the present invention.

[0019] Figure 3 is a graph of the TGA analysis results of 3-dimethylaminopropyldimethylbismuth, a compound prepared in Synthesis Example 1 of the present invention.

[0020] Figure 4 shows the viscosity analysis results of 3-dimethylaminopropyldimethylbismuth, a compound prepared in Synthesis Example 1 of the present invention.

[0021] Figure 5 shows the results of the Bi2O3 thin film process of dimethylaminodimethylbismuth, a compound prepared in Synthesis Example 1 of the present invention.

[0022] The aforementioned objectives, features, and advantages are described in detail below with reference to this specification, and accordingly, a person skilled in the art to which the present invention pertains will be able to easily implement the technical concept of the present invention. In describing the present invention, detailed descriptions of known technologies related to the present invention are omitted if it is determined that such descriptions may unnecessarily obscure the essence of the present invention.

[0023] Where terms such as "comprising," "having," "containing," "arranging," or "having" are used for a component in this specification, other parts may be added unless "only" is used. Where a component is expressed in the singular, it includes cases where it is included in the plural unless specifically stated otherwise.

[0024] Throughout this specification, unless specifically stated otherwise, each component may be singular or plural.

[0025] Throughout this specification, "A and / or B" means A, B, or A and B unless specifically stated otherwise, and "C to D" means C or more and D or less unless specifically stated otherwise.

[0026] Unless otherwise specifically stated in this specification, the standard of any unit is interpreted to mean "weight."

[0027] In interpreting the components in this specification, they are interpreted to include an error range even if there is no separate explicit description.

[0028]

[0029] The present invention will be described in more detail below.

[0030] The precursor for forming a metal-containing thin film according to the present invention is capable of forming a metal-containing thin film containing bismuth (Bi) on the surface of a substrate of a high dielectric material, and is characterized by comprising a compound represented by the following chemical formula 1.

[0031] [Chemical Formula 1]

[0032] In the above chemical formula 1,

[0033] M is bismuth (Bi), N means nitrogen, R1 to R4 are identical or different from each other and are each independently selected from hydrogen, a C1-C5 straight-chain alkyl group, a C3-C5 branched alkyl group, a C3-C8 cyclic alkyl group and a C2-C6 alkenyl group, and n is an integer from 1 to 5.

[0034] According to one example of the present invention, a compound in which M is bismuth (Bi) can be provided, and a bismuth-containing thin film can be formed using a precursor containing said compound.

[0035] According to one example of the present invention, R1 to R4 may be identical or different from each other and may each independently be a C1-C5 straight-chain alkyl group. The C1-C5 straight-chain alkyl groups each refer to a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group.

[0036] According to one example of the present invention, R1 to R4 are identical to each other and can be selected from C1-C3 straight-chain alkyl groups, for example, can be selected from methyl groups.

[0037] According to one example of the present invention, n can be selected as 3.

[0038] The compound represented by Chemical Formula 1 of the present invention can exhibit low viscosity, so it can solve problems such as insufficient vaporization during the transport of the liquid precursor that may occur when the viscosity of the precursor is high.

[0039] According to one example of the present invention, the compound represented by Formula 1 may satisfy the condition that the viscosity (@ 25°C, measured by a rotational viscometer) is 10 cP or less, for example 9 cP or less, for example 8 cP or less, for example 7 cP or less, for example 6 cP or less, for example 5 cP or less, for example 4 cP or less, for example 3 cP or less, for example 2 cP or less, and the lower limit value may not be specifically determined but may be, for example 0.5 cP or more.

[0040] The compound represented by Chemical Formula 1 of the present invention may have superior structural stability and thermal stability compared to metal compounds of the prior art. As a result, stable deposition is possible under various process conditions, for example, relatively high temperature conditions, and in particular, the stability of the chemical adsorption state is excellent, allowing for the formation of a uniform adsorption state on the surface of a substrate.

[0041] According to one example of the present invention, the high temperature condition may mean 200°C or higher, and preferably 240°C or higher. The high temperature condition may be, for example, 200°C to 500°C, for example, 200°C to 400°C, for example, 200°C to 350°C, for example, 220°C to 300°C, for example, 240°C to 280°C. In particular, it was experimentally confirmed that the compound precursor represented by Formula 1 of the present invention has an ALD window of 240 to 280°C. The ALD window is a temperature region where sufficient deposition of the precursor occurs but unwanted side reactions such as thermal decomposition or condensation do not occur, and it is a region where the growth thickness per cycle is maintained constant, and it can be viewed as a temperature range where the self-limiting reaction, which is a key characteristic required in the ALD process, is well performed.

[0042] The compound represented by Chemical Formula 1 of the present invention may be in a liquid state at room temperature, and even if it is in a solid state, it can be converted into a liquid state by dissolving it in a solvent. Since the liquid precursor can be subjected to conventional deposition methods such as the Liquid Delivery System (LDS), the efficiency of the thin film formation process can be significantly improved. This is because, unlike solid precursors, the liquid precursor is advantageous for uniform supply of the precursor onto the substrate. That is, the metal-containing thin film forming precursor is effective for performing the deposition process because it can apply all methods, such as the volatilization delivery method, which transfers volatilized gas of an organic solvent into the chamber of a reactor; the direct liquid injection method, which directly injects the liquid precursor composition; or the liquid delivery method, which transfers the precursor composition dissolved in an organic solvent.

[0043] According to one example of the present invention, a precursor for forming a metal-containing thin film may include a solvent capable of dissolving a compound represented by Formula 1, which means a dissolved state rather than a chemical bond to the metal-containing compound. Non-limiting examples of the solvent may include one or more of C1-C16 saturated or unsaturated hydrocarbons, ketones, esters, glyme, dimethoxyethane, diethyl ether, tetrahydrofuran, ether, dialkoxyalkane, pyridine, acetonitrile, primary amine solvents, secondary amine solvents, and tertiary amine solvents.

[0044] At this time, based on 100 weight% of the precursor for forming a metal-containing thin film, the content of the solvent may be 1 to 99 weight%, for example, 3 to 60 weight%, and more preferably 5 to 40 weight%. By dissolving the metal-containing compound using a solvent in this way, the concentration of metal atoms can be lowered, thereby providing a suitable precursor that responds to various deposition process conditions.

[0045] The method for forming a metal-containing thin film according to the present invention can form a thin film composed of a metal, a metal oxide, a metal nitride, a metal oxynitride, or a metal sulfide by forming a thin film on a substrate using the precursor for forming a metal-containing thin film.

[0046] According to the method for forming a metal-containing thin film of the present invention, the method may include: a first step of preparing a substrate in a reactor; a second step of forming a metal-containing thin film by depositing a precursor for forming a metal-containing thin film on the surface of the substrate; and a third step of reacting the metal-containing thin film with a reactive gas, wherein the precursor for forming a metal-containing thin film comprises a compound represented by Formula 1 of the present invention.

[0047] According to one example of the present invention, the material of the substrate may include a III-V semiconductor material including silicon (Si), germanium (Ge), germanium tin (GeSn), silicon germanium (SiGe), silicon germanium tin (SiGeSn), and silicon carbide (SiC); a silicon-containing dielectric material such as silicon oxide (SiOx), silicon nitride (Si3N4), silicon oxynitride (SiON), silicon oxycarbide (SiOC), silicon oxycarbide nitride (SiOCN), and silicon carbon nitride (SiCN); or a dielectric material including a metal oxide such as aluminum oxide (Al2O3), hafnium oxide (HfO2), tantalum oxide (Ta2O5), zirconium oxide (ZrO2), titanium oxide (TiO2), hafnium silicate (HfSiOx), and lanthanum oxide (La2O3), but is not limited thereto.

[0048] According to one example of the present invention, the second step may involve vaporizing the precursor for forming the metal-containing thin film, transferring it into a reactor, and depositing it.

[0049] According to one example of the present invention, a deposition process can be performed by supplying the precursor for forming a metal-containing thin film to a substrate using a liquid delivery method. By using a liquid delivery system (LDS) to convert the liquid precursor composition into a gaseous phase through a vaporizer and then transferring it onto a substrate for forming a metal-containing thin film, a second deposition process can be performed.

[0050] According to one example of the present invention, the deposition of the second step is not particularly limited as long as it is a process for depositing a precursor for forming a metal-containing thin film on a substrate, and may be selected from, for example, a spin-on dielectric (SOD) process, a low temperature plasma (LTP) process, chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), high density plasma-chemical vapor deposition (HDPCVD) process, atomic layer deposition (ALD) process, and plasma-enhanced atomic layer deposition (PEALD) process.

[0051] According to one example of the present invention, the deposition of the second step can be performed at a high temperature of 200°C or higher, for example, in a range of 200°C to 500°C, for example, 200°C to 400°C, for example, 200°C to 350°C.

[0052] According to one example of the present invention, the deposition process of the second step may include one or more purge gases. The purge gas is selected as an inert gas that does not react with the precursor, for purging unconsumed reactants and / or reaction by-products. The purge gas may include one or more of argon (Ar), nitrogen (N2), helium (He), neon (Ne), and hydrogen (H2), but is not limited thereto. At this time, the purge gas may be used to purge within a pressure range of 1 to 5 Torr.

[0053] By including a third step of reacting the precursor thin film deposited in the second step with a reactive gas, a metal oxide, metal nitride, metal oxynitride, or metal sulfide thin film can be formed.

[0054] According to one example of the present invention, the reactive gas of the third step may include one or more selected from nitrogen (N2), ammonia (NH3), hydrazine (N2H4), nitrous oxide (N2O), oxygen (O2), water vapor (H2O), ozone (O3), hydrogen peroxide (H2O2), silane (SiH4), hydrogen (H2), and diborane (B2H6), but is not limited thereto.

[0055] According to one example of the present invention, the third step may be performed by supplying a gaseous reactant containing a reactive gas into a reactor and bringing it into contact with a substrate. In this way, a metal-containing thin film may be formed by bringing a precursor for forming a metal-containing thin film into contact with a substrate, and then a final thin film may be formed by bringing it into contact with a reactive gas.

[0056] In addition, when supplying the precursor for forming the metal-containing thin film, additional metal precursors may be supplied to improve electrical properties such as the capacitance of the final metal-containing thin film, and the additional metal is selected to be of a different type from M of Formula 1. The additional metal may include, for example, one or more metals selected from silicon (Si), titanium (Ti), germanium (Ge), strontium (Sr), barium (Ba), hafnium (Hf), zirconium (Zr), and lanthanide atoms, but is not limited thereto. In addition, the additional metal precursor may be supplied in the form of an alkylamide compound or an alkoxy compound containing the additional metal.

[0057] As described above, a series of processes including the introduction of a precursor for forming a metal-containing thin film, the introduction of a reactive gas, and optionally the introduction of an additional metal precursor constitutes one cycle, and by repeating this process for one or more cycles, a desired metal-containing thin film can be formed.

[0058] A metal-containing thin film formed from a precursor for forming a metal-containing thin film comprising a compound represented by Chemical Formula 1 of the present invention serves as a component of an electronic device such as a semiconductor device, and various types of devices can be manufactured based thereon. Semiconductor devices comprising the metal-containing thin film may include memory devices such as 3D-NAND and DRAM, gate electrodes for semiconductors, capacitor electrodes for DRAM, channel materials for TFTs, etc., but are not limited thereto.

[0059]

[0060] [Synthesization Example 1] Synthesis of 3-Dimethylaminopropyldimethylbismuth

[0061] <Reaction Equation 1>

[0062]

[0063] Chlorodimethylbismuth, an intermediate, was synthesized according to the above reaction scheme 1, and specifically, the process was carried out as follows.

[0064] 50 g (0.1586 mol) of bismuth(III) chloride was placed in a 1,000 ml three-neck flask, a dropping funnel and a thermometer were installed, and the inside of the flask was purged with nitrogen. 300 ml of tetrahydrofuran was added and stirred to disperse the bismuth(III) chloride; then, while maintaining the temperature below 0°C, 103.06 ml (0.3092 mol) of a 3 M methyl magnesium chloride / tetrahydrofuran solution was added dropwise from the dropping funnel over a period of 30 minutes. A black precipitate formed immediately upon adding. During this time, the internal temperature rose to 10°C. After the addition was finished, the mixture was stirred until it reached room temperature. The filtrate remaining after filtration was a mixture of chlorodimethylbismuth and tetrahydrofuran and was used for the final synthesis of dimethylaminopropyldimethylbismuth.

[0065] <Reaction Equation 2>

[0066]

[0067] 3-dimethylaminopropyldimethylbismuth was synthesized according to Reaction Scheme 2 using chlorodimethylbismuth, the product of Reaction Scheme 1 above, as a reactant, and specifically, the process was carried out as follows.

[0068] 600 ml of hexane was placed in a 5,000 ml three-neck flask, a dropping funnel and a thermometer were installed, and the inside of the flask was purged with nitrogen. Approximately 400 ml of a chlorodimethylbismuth / tetrahydrofuran mixture was added and stirred; then, while maintaining the temperature below 0°C, 158.56 ml (0.1586 mol) of a 1 M dimethylaminopropylmagnesium chloride / tetrahydrofuran solution was added dropwise from the dropping funnel over a period of 30 minutes. A gray precipitate formed simultaneously with the addition. During this time, the internal temperature rose to 5°C–6°C. After the addition was finished, the mixture was stirred until it reached room temperature. The mixture was filtered under reduced pressure at a temperature below 60°C, and after removing the reaction solvent, 10.3 g of purified 3-dimethylaminopropyldimethylbismuth was obtained by vacuum distillation.

[0069]

[0070] [Experimental Example 1] 1 H-NMR analysis

[0071] The 3-dimethylaminopropyldimethyl bismuth obtained in Synthesis Example 1 above was used with Bruker ASCEND TM The results of the 1H-NMR analysis (MHz, D8, 25℃) using 400 equipment are shown in Figure 1, and it was confirmed that the target compound was synthesized by identifying specific peaks at δ0.97(s, 6H), δ1.89-1.92(t, 2H), δ2.07-2.09(t, 2H), δ2.13(s, 6H), and δ2.19-2.23(t, 2H).

[0072]

[0073] [Experimental Example 2] Gas Chromatography Mass Spectrometry

[0074] The 3-dimethylaminopropyldimethyl bismuth obtained in Synthesis Example 1 was analyzed by gas chromatography-mass spectrometry (GC-MS) using an Agilent 8850 instrument. The graph of the GC-MS analysis results is shown in Figure 2.

[0075]

[0076] [Experimental Example 3] Thermogravimetric Analysis

[0077] The 3-dimethylaminopropyldimethylbismuth obtained in Synthesis Example 1 was subjected to thermogravimetric analysis (TGA) using an SDT Q600 instrument. The graph of the TGA analysis results is shown in Fig. 3. As a result of the TGA analysis, T i (initial temperature) is 33.29℃, T f The final temperature was 145.12℃, and the residue mass was 0.008%.

[0078]

[0079] [Experimental Example 4] Viscosity Analysis

[0080] The 3-dimethylaminopropyldimethyl bismuth obtained in Synthesis Example 1 was subjected to viscosity analysis three times using an A&D Company SV-10 instrument at 0.3–250 rpm under conditions of 25°C. The results of the viscosity analysis are shown in Figure 4. The average viscosity analysis result was 1.91 cP (@25°C), which is significantly lower than the target viscosity of 10 cP (@25°C) or less.

[0081]

[0082] [Experimental Example 5] Preparation of Bi2O3 Thin Film

[0083] The 3-dimethylaminopropyldimethylbismuth obtained in Synthesis Example 1 was subjected to atomic layer deposition (ALD) under the conditions shown in Table 1 below. The ALD window was observed at 240–280°C, and the deposition conditions and results are shown in Figure 5.

[0084] [Table 1]

[0085]

[0086] In Table 1 above, "Can" refers to the temperature of the canister filled with 3-dimethylaminopropyldimethylbismuth obtained in Synthesis Example 1, and "Stage" refers to the deposition temperature as the wafer heating temperature. Additionally, the composition ratio of the Bi2O3 thin film at the temperature of the region showing the ALD window was confirmed through XPS analysis (X-ray Photoelectron Spectroscopy) and is shown in Table 2 below, and the density and surface roughness were confirmed through XRR (X-ray Reflectivity Analysis) and are shown in Table 3 below.

[0087] [Table 2]

[0088]

[0089] [Table 3]

[0090]

[0091]

[0092] Although the present invention has been described in more detail with reference to the embodiments and drawings of this specification, this specification is not necessarily limited to these embodiments and drawings, and various modifications may be made within the scope of the technical spirit of this specification. Accordingly, the embodiments and drawings disclosed in this specification are intended to explain, not limit, the technical spirit of this specification, and the scope of the technical spirit of this specification is not limited by these embodiments. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. The scope of protection of this specification shall be interpreted by the claims, and all technical spirits within an equivalent scope shall be interpreted as being included within the scope of rights of this specification.

Claims

1. A precursor for forming a metal-containing thin film comprising a compound represented by the following chemical formula 1. [Chemical Formula 1] In the above chemical formula 1, M is bismuth (Bi), and N stands for nitrogen, R1 to R4 are identical or different from each other and are each independently selected from hydrogen, a C1-C5 straight-chain alkyl group, a C3-C5 branched alkyl group, a C3-C8 cyclic alkyl group, and a C2-C6 alkenyl group, and n is an integer from 1 to 5.

2. In Paragraph 1, A precursor for forming a metal-containing thin film, characterized in that the above R1 to R4 are identical or different from each other and each is independently a C1-C5 straight-chain alkyl group.

3. In Paragraph 1, A precursor for forming a metal-containing thin film, characterized in that n is 3.

4. In Paragraph 1, A precursor for forming a metal-containing thin film, characterized by a viscosity (@ 25℃) of 10 cP or less.

5. First step of preparing a substrate in a reactor; A second step of forming a metal-containing thin film by depositing a precursor for forming a metal-containing thin film according to any one of claims 1 to 4 on the surface of the substrate; and A third step of reacting the above metal-containing thin film with a reactive gas; comprising Method for forming a metal-containing thin film.

6. In Paragraph 5, A method for forming a metal-containing thin film, characterized in that the second step above involves vaporizing the precursor for forming the metal-containing thin film, transferring it into a reactor, and depositing it.

7. In Paragraph 5, A method for forming a metal-containing thin film, characterized in that the deposition in the second step is performed by a process selected from a spin-on dielectric (SOD) process, a low temperature plasma (LTP) process, chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), high density plasma-chemical vapor deposition (HDPCVD), atomic layer deposition (ALD) process, and plasma-enhanced atomic layer deposition (PEALD) process.

8. In Paragraph 5, A method for forming a metal-containing structure, characterized in that the deposition in the second step is performed by an atomic layer deposition (ALD) process at a temperature range of 240°C or higher.

9. In Paragraph 8, A method for forming a metal-containing structure, characterized in that the deposition in the second step is performed by an atomic layer deposition (ALD) process in a temperature range of 240 to 280°C.

10. In Paragraph 5, A method for forming a metal-containing thin film, characterized in that the reactive gas of the third step comprises one or more selected from nitrogen (N2), ammonia (NH3), hydrazine (N2H4), nitrous oxide (N2O), oxygen (O2), water vapor (H2O), ozone (O3), hydrogen peroxide (H2O2), silane (SiH4), hydrogen (H2), and diborane (B2H6).

11. A semiconductor device comprising a metal-containing thin film formed by depositing a precursor for forming a metal-containing thin film according to any one of claims 1 to 4 on the surface of the substrate.

Images