KR100459609B1 - organic cobalt compounds for cobalt or cobalt salicide thin film and method thereof and method of cobalt thin film - Google Patents

Abstract

The organic cobalt compound for depositing cobalt and cobalt silicide thin films according to the present invention includes an organic cobalt compound having a structure of Formula 1 below. <Formula 1> In Formula 1, L is a neutral ligand, alkane (alkyne; C _n H _2n-2 ), alkyne (alkene; C _n H _2n ), diene, triene, cyclic diene (cyclic diene) ), Cyclic triene, isocyanide, alkyl nitrile, or any one of these, n is 1 to 4.

Description

Organic cobalt compounds for cobalt or cobalt salicide thin film and method about and cobalt thin film for cobalt and cobalt silicide thin film deposition

The present invention relates to an organic cobalt compound for depositing a thin film containing cobalt, such as cobalt and cobalt silicide, and a method for manufacturing the same. More particularly, the present invention is applicable to chemical vapor deposition or atomic layer deposition and is thermally and chemically stable organic. The present invention relates to a cobalt compound, a method for preparing the same, and a method for preparing a cobalt and cobalt silicide thin film using the organic cobalt compound.

Conventionally, in order to manufacture a cobalt (Co) thin film, silicon (Si) was deposited by physical vapor deposition (Physical Vaper Deposition) such as sputtering or thermal evaporation.

In addition, it has excellent thermal stability, chemical stability, and low resistivity (10 ~ 18μΩcm), so it is applied to gate electrodes, interconnects, contact layers, and cobalt applied to digital recording media such as magneto-optical memory. In order to prepare a silicide (CoSi ₂ ) thin film, the cobalt thin film prepared as described above was annealed at about 500 ° C. or more after deposition, or prepared using molecular beam epitaxy (MBE).

However, as the integration degree of memory and non-memory semiconductor devices increases and the structure becomes more complicated, high aspect ratio and excellent step coverage of cobalt thin films are evaluated as important process factors. The same physical vapor deposition method was limited.

Therefore, a thin film manufacturing method widely used as an alternative to the conventional physical vapor deposition method is a metal organic chemical vapor deposition method (MOCVD) method using a volatile organometallic compound. The MOCVD method is decomposed after adsorption of the vaporized organometallic compound on a heated substrate by various methods such as bubbling by a carrier gas or vaporizing the injected liquid raw material with a vaporizer. It is the principle of deposition.

These chemical vapor deposition methods tend to replace conventional physical vapor deposition methods such as sputtering and thermal evaporation because they have high aspect ratios and excellent step coverage, which are essential for high-integration devices. In order to obtain step coverage, atomic layer deposition (ALD) has been applied.

The atomic layer deposition method is a method of depositing an atomic layer on a semiconductor substrate by sequentially injecting and removing a reactant into a chamber. The atomic layer deposition method is a deposition method using a chemical reaction, such as chemical vapor deposition (CVD), but CVD in that each type of gas is injected at the same time and flows in a pulse by one kind of gas without mixing in the chamber. It is distinguished from the law.

In this case, the chemical vapor deposition or atomic layer deposition method has a condition that the compound has a high vaporization characteristics, a large gap between the vaporization temperature and decomposition temperature, low toxicity, chemical stability, thermal stability and easy compound synthesis and pyrolysis . In addition, there should be no side reactions spontaneously decomposing or reacting with other substances in the process of vaporization and transfer to the gas phase, and especially in the case of atomic layer deposition, the reaction with the reaction gas should be easy.

Conventionally used cobalt deposition compounds include Co (CO) ₃ (NO) [cobalt tricarbonyl nitrosyl], Co (CO) ₂ Cp [cabalt dicarbonyl cyclopentadienyl], Co ₂ (CO) ₈ [dicobalt octacarbonyl], CoCp ₂ [biscyclopentadienyl cobalt] and the like are known.

However, although Co (CO) ₃ (NO) and Co (CO) ₂ Cp compounds are liquid and have a high vapor pressure, they may cause a lot of difficulties in the process due to thermal instability such as pyrolysis at room temperature. Furthermore, Co ₂ (CO) ₈ , CoCp ₂ compounds are not only solid but also have relatively low vapor pressures, which present more and more difficulties in the application of the process. In addition, the cyclopentadienyl compounds were relatively high as the deposition temperature was higher than 300 ° C, and the carbon contamination was severe due to the decomposition characteristics of the ligands.

The present invention has been made to solve the problems as described above, in the manufacturing process of the thin film using the chemical vapor deposition method or atomic layer deposition method to improve the process problems due to the thermal and chemical instability of the raw material compound, excellent thermal stability and high Organic cobalt compounds for the deposition of cobalt and cobalt silicide thin films that do not react sensitively to vapor pressure, moisture, air, etc., and make it possible to deposit pure cobalt thin films free of impurities such as carbon by only changing process conditions such as changes in reaction gas and deposition temperature. And to provide a method for manufacturing the same and a thin film has an object.

The following drawings attached to this specification are illustrative of preferred embodiments of the present invention, and together with the detailed description of the invention to serve to further understand the technical spirit of the present invention, the present invention is a matter described in such drawings It should not be construed as limited to.

1 is a view showing a device used in the atomic layer deposition method.

2 and 3 are graphs showing the thermal stability test results of the cobalt compound prepared according to the present invention, Figure 2 shows the state before heating storage, Figure 3 shows the state 2 months after heating storage.

In order to achieve the above object, an organic cobalt compound for depositing a cobalt and cobalt silicide thin film according to the present invention includes an organic cobalt compound having a structure of Formula 1 below.

In Formula 1, L is a neutral ligand, alkane (alkyne; C _n H _2n-2 ), alkyne (alkene; C _n H _2n ), diene, triene, cyclic diene (cyclic diene) ), Cyclic triene, isocyanide, alkyl nitrile, or any one of these, n is 1 to 4.

Preferably, in the organic cobalt compound of the present invention, the neutral ligand L includes an organic cobalt compound, characterized in that it comprises an organic compound, such as the following formula (2).

1) alkyne: R ¹ -C≡CR ²

2) alkene: R ³ R ⁴ C = CR ⁵ R ⁶

3) diene: R ⁷ R ⁸ C = CR ⁹ -CR ¹⁰ = CR ¹¹ R ¹²

4) triene: R ¹³ R ¹⁴ C = CR ¹⁵ -CR ¹⁶ = CR ¹⁷ -CR ¹⁸ = CR ¹⁹ R ²⁰

5) Cyclic diene: 1,3 (1,4) -cyclohexadiene, 1,3 (1,4) -cycloheptadiene,

cyclopentadiene, 1,5-cyclooctadiene, 1,5-dimethyl-1,

5-cyclooctadiene

6) Cyclic triene: 1,3,5-cycloheptadiene

7) isocyanide: R ²¹ -NC

8) alkyl nitrile: R ²² -CN

In Formula 2, R ¹ to R ²² are each independently hydrogen (H), carbon (C) 1 to 10 saturated or unsaturated alkyl, (or) fluorinated alkyl, alkoxyalkyl (-CR ₂ OR), aminoalkyl (-CR ₂ NR ₂ ), alkylsilicone (-SiR ₃ ), alkoxysilicone (-Si (OR) ₃ ), alkylalkoxysilicon (-Si (R) _3-n (OR) _n ), alkylsilyloxy (- OSiR ₃ ), alkoxy (-OR), alkylamino (-NR ₂ ) may be employed, and especially in the case of cyclic dienes, as well as the compounds exemplified in 5) and 6) Hydrogen (H), saturated or unsaturated alkyl of from 1 to 10 carbon atoms, (also) fluorinated alkyl, alkoxyalkyl (-CR ₂ OR), aminoalkyl (-CR ₂ NR ₂ ), alkylsilicone (-SiR ₃ ), Alkoxysilicon (-Si (OR) ₃ ), Alkylalkoxysilicon (-Si (R) _3-n (OR) _n ), Alkylsilyloxy (-OSiR ₃ ), Alkoxy (-OR), Alkylamino (-NR ₂ It is preferable that any one of) contains the compound substituted.

Further, according to the present invention, alkane compounds of 1) of Formula 2 are preferable among the compounds prepared as in Chemical Formula 1, and more preferably, R ¹ and R ² are each independently hydrogen to an alkyl group having from 1 to 10 carbon atoms. And a compound having a trialkylsilicone group. Representative compounds include t-butylacetylene (R ¹ = H, R ² = t-butyl), trimethylsilylacetylene (R ¹ = H, R ² = trimethylsilyl; -SiMe ₃ ), bistrimethylsilylacetylene (R ¹ , R ² = trimethylsilyl; -SiMe ₃ ), triethylsilylacetylene, 1-trimethylsilyl-1-propyne, 1 (2) -pentyne, 1 (2) (3) -hexane hexyne, 1 (2) -heptyne, 1 (2) (4) -octane and the like.

According to another aspect of the invention, the method for producing an organic cobalt compound of the present invention comprises the step of first adding a solvent to the cobalt carbonyl, and adding the organic compound of formula 2 to the mixture solution It includes a method for producing an organic compound characterized by. In addition, the solvent used preferably contains any of saturated and unsaturated, aromatic hydrocarbons, (ring) ethers, esters, (ring) amines, alcohols, and acetone.

The cobalt compound described above may be used as a raw material in a chemical vapor deposition method or an atomic layer deposition method as a method for producing a cobalt and cobalt silicide thin film, wherein the compounds are prepared by the preparation process shown in Scheme 1 below.

Ligand (L) is added to Co ₂ (CO) ₈ as a raw material to induce a spontaneous substitution reaction of the ligand. In this case, all reaction processes are performed in order to exclude contact with air (Ar, N _2). Takes place).

In more detail, cobaltcarbonyl (Co ₂ (CO) ₈ ) and alkyne represented by L of Chemical Formula 2 (C _n H _2n-2 ), alkyne (alkene; C _n H _2n ), die Cobalt compounds desired by reacting compounds such as diene, triene, cyclic diene, cyclic triene, isocyanide and alkyl nitrile To prepare. To this end, first, cobalt carbonyl as a solid is diluted in a solvent to prepare a dispersion solution. Thereafter, a ligand compound is reacted with the dispersion solution to produce a cobalt compound.

In addition, in order to improve the deposition properties of the compound for thin film deposition including cobalt can be prepared in the form of a mixture by adding one or more of the organic compounds of the formula (2) to the prepared cobalt compound (Formula 1), on the other hand Examples of the compound represented by Formula 1 include saturated or unsaturated hydrocarbons, ethers (including cyclic ethers), esters, alcohols, amines (including cyclic amines), sulfides (including cyclic sulfides), phosphines, and beta-dikitones. It is also possible to add cobalt compounds by adding organic compounds such as beta-chitoesters.

On the other hand, as the solvent usable in the reaction, saturated and unsaturated, aromatic hydrocarbons, (ring) ethers, esters, (ring) amines, alcohols, acetone, and the like are preferable, more preferably petroleum ether, hexane, pentane, heptane, Ethyl ether, tetrahydrofuran (THF), benzene, toluene, ethyl alcohol, methyl alcohol, isopropyl alcohol, acetone are employed.

Hereinafter, the production method of the compound will be described with specific examples.

1) Preparation of -Co ₂ (CO) ₆ (t-butylacetylene)

First, 100 mL of petroleum ether is added to the raw material Co ₂ (CO) ₈ (40 g, 0.117 mol) to prepare a dark brown dispersion solution. T-butylacetylene (9.6 g, 0.117 mol) is added to the prepared dispersion, and the mixture is stirred at room temperature for about 12 hours. As the reaction proceeds, carbon monoxide (CO) gas is generated, and when the reactant Co ₂ (CO) ₈ solid is dissolved and gas generation stops, the reaction is considered to have ended. At the end of the reaction, the solvent was removed from the dark red solution using a liquid nitrogen trap, followed by vacuum distillation at 80 ° C. to 90 ° C. to obtain a dark red primary product (39 g). The primary compound was prepared by heating to 55-60 ° C. under reduced pressure (0.1torr) and distilling deep red pure product -Co ₂ (CO) ₆ (t-butylacetylene) into a vessel cooled with dry ice. do. The prepared compound was analyzed for residual organic matter using ¹ H ( ¹³ C) -NMR, the residual trace metal impurities were analyzed using ICP-MS, the results are shown in Table 1 below.

Preparation of 2) -Co ₂ (CO) ₆ (trimethylsilylacetylene)

After reacting Co ₂ (CO) ₈ (40 g, 0.117 mole) with trimethylsilylacetylene (0.117 mole) in the same manner as the process for preparing compound -Co ₂ (CO) ₆ (t-butylacetylene), about 60 ° C to Vacuum distillation at 70 ° C. yielded compound -Co ₂ (CO) ₆ (trimethylsilylacetylene) (yield 70%). The prepared compound was analyzed for residual organic matter using ¹ H ( ¹³ C) -NMR, the residual trace metal impurities were analyzed using ICP-MS, the results are shown in Table 1 below.

3) -Co ₂ (CO) ₆ (L) Preparation

Co ₂ (CO) ₈ (40 g, 0.117 mol) and t-butyl isocyanide, trimethylsilyl cyanide, trimethylacetonitrile in the same manner as in the preparation of the compound -Co ₂ (CO) ₆ (t-butylacetylene) ( 0.117 mole), and the like are reacted separately, and then vacuum distilled in the range of about 70 ° C. to 80 ° C. to give compounds -Co ₂ (CO) ₆ (t-butyl isocyanide) and -Co ₂ (CO) ₆ (trimethylsilyl cyanide). ), -Co ₂ (CO) ₆ (trimethylacetonitrile) (yield 70%), respectively. The prepared compound was analyzed for residual organic matter using ¹ H ( ¹³ C) -NMR, the residual trace metal impurities were analyzed using ICP-MS, the results are shown in Table 1 below.

compound Breaking point (℃ / torr) H-NMR spectrum (ppm) Co ₂ (CO) ₆ (t-butylacetylene) 55 / 0.1 5.5 (s), 1.1 (s) Co ₂ (CO) ₆ (trimethylsilylacetylene) 60 / 0.1 5.1 (s), 0.1 (s) Co ₂ (CO) ₆ (bistrimethylsilylacetylene) 80 / 0.1 0.12 (s) Co ₂ (CO) ₆ (1-hexyne) 65 / 0.1 5.5 (s), 2.2 (t), 1.7 (m), 1.5 (m), 0.9 (t) Co ₂ (CO) ₆ (1-pentyne) 55 / 0.1 5.5 (s), 2.2 (t), 1.5 (m), 0.9 (t) Co ₂ (CO) ₆ (t-butyl isocyanide) 70 / 0.1 1.5 (s) Co ₂ (CO) ₆ (trimethylsilylnitrile) 75 / 0.1 0.2 (s)

Table 1 can be seen that by the ¹ H-NMR spectrum as a breaking point at the time of ¹ H-NMR spectra of the compounds prepared by the method of Scheme 1 with distilled compound is prepared in pure water. The compounds have a suitable vapor pressure required for deposition as a liquid or solid distilled in the range of 55 ~ 80 ℃, it can be confirmed that the thermal stability is excellent because no thermal decomposition during distillation. In particular, the Co ₂ (CO) ₆ (t-butylacetylene) compound is a liquid and has the highest vapor pressure, excellent thermal stability (see the spectra of FIGS. 2 and 3), and does not readily decompose upon exposure to air. Since it does not react, it can be seen that the organic cobalt compound is most easily applied to a process for cobalt deposition.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the present specification and claims should not be construed as being limited to the common or dictionary meanings, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

1 is a view showing an apparatus used in the atomic layer deposition method, a cobalt or cobalt silicide thin film is prepared by employing the organic cobalt compound prepared according to the present invention.

With reference to the drawings looks at a method for producing a cobalt thin film using the compound -Co ₂ (CO) ₆ (t-butylacetylene) prepared by the method 1). First, -Co ₂ (CO) ₆ (t-butylacetylene), a raw material, is stored in a stainless steel bubbler container (not shown), and a carrier gas such as hydrogen, nitrogen, or argon is heated at a temperature of 60 ° C or lower. In addition, helium and the like are supplied in the gas state into the reaction chamber 10 through the gas inlets 20 and 22. At this time, the supply of the raw material may be used separately or using a gas inlet, such as a transport gas. The cobalt compound supplied is deposited on the silicon wafer 30 heated to a temperature of room temperature to 500 ° C to form a thin film. When a thin film is deposited, the process is repeated until the predetermined thickness is achieved while discharging the residual gas to the pump 40. At this time, by introducing a reaction gas such as hydrogen, silane or ammonia into the chamber, the deposition rate and the deposition temperature can be improved. On the other hand, the cobalt silicide thin film can be prepared by annealing at 300 ° C. or higher as described in the prior art.

In addition, according to the present invention, the cobalt compound prepared according to Scheme 1 has a general chemical vapor deposition method of continuously injecting a cobalt source and a reaction gas into a film during the deposition process, and an atomic layer deposition method of sequentially introducing a cobalt source and a reaction gas. All can be adopted.

2 and 3 are graphs showing the thermal stability test results of the cobalt compound -Co ₂ (CO) ₆ (t-butylacetylene) prepared according to the present invention. Since the compound prepared in the present invention is a thermal stability test at the process temperature is essential to ensure reproducibility during the process, it was examined whether the compound is deteriorated while heated to a process temperature of 60 ° C. Experimental method was put in a glass sample container containing several grams of compound and kept in a chamber kept heated to 60 ℃, and analyzed with ¹ H-NMR equipment over time. Figure 2 is a view showing a state before heating storage, Figure 3 shows the result of a state elapsed two months or more after heating storage. As can be seen in Figure 3, even after two months or more after heating and storage, the initial state, that is, the same appearance and ¹ H-NMR spectrum as shown in Figure 2.

As mentioned above, although this invention was demonstrated by the limited embodiment and drawing, this invention is not limited by this and is within the equal range of a common technical idea in the technical field to which this invention belongs, and a claim to be described below. Of course, various modifications and variations are possible.

According to the present organic cobalt compound for cobalt and cobalt silicide thin film deposition, a method of manufacturing the same, and a thin film manufacturing method, it is possible to secure reproducibility during the deposition process because of excellent thermal and chemical stability and little reactivity with air or moisture. Organic compounds can be prepared. In addition, the organic cobalt compound can easily grow a pure cobalt thin film by simple pyrolysis, and can significantly improve the deposition rate or deposition temperature by using a suitable reaction gas such as hydrogen, silane, or ammonia. In addition, the organic cobalt compound is used as a raw material in the chemical vapor deposition method or atomic layer deposition method to produce a cobalt or cobalt silicide thin film, especially when using an atomic layer deposition method of introducing a cobalt source and a reaction gas sequentially It can exhibit excellent step coverage in a highly integrated semiconductor device process exhibiting a ratio.

Claims (9)

An organic cobalt compound having a structure of Formula 1 below for depositing cobalt and cobalt silicide thin films. <Formula 1> In Formula 1, L is a neutral ligand, alkane (alkyne; C _n H _2n-2 ), alkyne (alkene; C _n H _2n ), diene, triene, cyclic diene (cyclic diene) ), Cyclic triene, isocyanide, alkyl nitrile, or any one of these, n is 1 to 4. The method of claim 1, The neutral ligand (L) is an organic cobalt compound, characterized in that it comprises an organic compound, such as the formula (2). <Formula 2> 1) alkyne: R ¹ -C≡CR ² 2) alkene: R ³ R ⁴ C = CR ⁵ R ⁶ 3) diene: R ⁷ R ⁸ C = CR ⁹ -CR ¹⁰ = CR ¹¹ R ¹² 4) triene: R ¹³ R ¹⁴ C = CR ¹⁵ -CR ¹⁶ = CR ¹⁷ -CR ¹⁸ = CR ¹⁹ R ²⁰ 5) Cyclic diene: 1,3 (1,4) -cyclohexadiene, 1,3 (1,4) -cycloheptadiene, cyclopentadiene, 1,5-cyclooctadiene, 1,5-dimethyl-1, 5-cyclooctadiene 6) Cyclic triene: 1,3,5-cycloheptadiene 7) isocyanide: R ²¹ -NC 8) alkyl nitrile: R ²² -CN In Formula 2, R ¹ to R ²² are each independently hydrogen (H), carbon (C) 1 to 10 saturated or unsaturated alkyl, (or) fluorinated alkyl, alkoxyalkyl (-CR ₂ OR), aminoalkyl (-CR ₂ NR ₂ ), alkylsilicone (-SiR ₃ ), alkoxysilicone (-Si (OR) ₃ ), alkylalkoxysilicon (-Si (R) _3-n (OR) _n ), alkylsilyloxy (- OSiR ₃ ), alkoxy (-OR), alkylamino (-NR ₂ ), and in the case of cyclic dienes, as well as the compounds exemplified in 5), 6) of Formula 2 as well as hydrogen ( H), saturated or unsaturated alkyl having 1 to 10 carbon atoms, (also) fluorinated alkyl, alkoxyalkyl (-CR ₂ OR), aminoalkyl (-CR ₂ NR ₂ ), alkylsilicone (-SiR ₃ ), alkoxysilicone In (-Si (OR) ₃ ), alkylalkoxysilicones (-Si (R) _3-n (OR) _n ), alkylsilyloxy (-OSiR ₃ ), alkoxy (-OR), alkylamino (-NR ₂ ) An organic cobalt compound, characterized in that it contains a compound which is substituted. The method according to claim 1 or 2, The neutral ligand (L) is t-butylacetylene (R ¹ = H, R ² = t-butyl), trimethylsilylacetylene (R ¹ = H, R ² = trimethylsilyl; -SiMe ₃ ), bistrimethylsilylacetylene ( R ¹ , R ² = trimethylsilyl; -SiMe ₃ ), triethylsilylacetylene, 1-trimethylsilyl-1-propyne, 1 (2) -pentyne, 1 (2) (3) An organic cobalt compound comprising any one of hexayne, hexyne, 1 (2) -heptyne, and 1 (2) (4) -octane. The method according to claim 1 or 2, The neutral ligand (L) is an organic cobalt compound, characterized in that it comprises any one of t-butyl iso dioxide, trimethyl acetonitrile, trimethyl silyl cyanide. A method of preparing a cobalt or cobalt silicide thin film by chemical vapor deposition or atomic layer deposition using the organic cobalt compound of claim 1 or 2. A method of depositing a thin film comprising cobalt by chemical vapor deposition or atomic vapor deposition using a mixture containing at least one organic compound of formula 2) in the compound of claim 1. At least one saturated or unsaturated hydrocarbons, ethers (including cyclic ethers), esters, alcohols, amines (including cyclic amines), sulfides (including cyclic sulfides), phosphines, beta-dikitones, A method of depositing a thin film containing cobalt by chemical vapor deposition or atomic vapor deposition using a mixture containing organic compounds such as beta-chitoesters. In the method for producing an organic cobalt compound, Preparing a dispersion solution by adding a solvent to cobalt carbonyl, Adding the organic compound of Formula 2 to the dispersion solution; The solvent is any one of saturated and unsaturated, aromatic hydrocarbon, (ring) ether, ester, (ring) amine, alcohol, acetone is employed. The method of claim 8, The solvent is any one of petroleum ether, hexane, pentane, heptane, ethyl ether, tetrahydrofuran (THF), benzene, toluene, ethyl alcohol, methyl alcohol, isopropyl alcohol, acetone.