KR102578747B1 - Ruthenium organometallic compound, and method for producing same - Google Patents

Abstract

The present invention relates to a novel ruthenium organometallic compound that has improved thermal stability and is liquid at room temperature, enabling the production of high-quality ruthenium thin films even at low temperatures, and a method for producing the same.

Description

Ruthenium organometallic compound and method for producing same}

The present invention relates to a ruthenium organometallic compound useful as a raw material for manufacturing semiconductor devices and a method for producing the same.

Ruthenium is useful as an electrode material because not only ruthenium itself but also its oxide has electrical conductivity, and it also has excellent micronization processability. Due to the stable electrode characteristics and excellent processability of ruthenium, ruthenium is being used as an electrode material for miniaturization of memory cells due to the high integration of semiconductor memory devices. In particular, ruthenium thin films are used as electrode materials for DRAM capacitors, which are highly integrated memory devices, or as diffusion barriers for copper wiring materials in semiconductor devices.

Meanwhile, chemical vapor deposition (CVD) or atomic layer deposition (ALD) is used as a manufacturing method for ruthenium-containing thin films in highly integrated memory devices.

In particular, as an organometallic compound for forming a ruthenium thin film or ruthenium oxide thin film by the CVD method, a compound that is liquid at room temperature, has excellent handling properties, and can be supplied stably in terms of stability and vapor pressure is more likely to form a ruthenium thin film or ruthenium oxide thin film. It is advantageous for use.

In addition, since the ruthenium thin film process is achieved by high-temperature thermal decomposition of ruthenium organometallic compounds, compounds with high temperature stability and less residual substances after thermal decomposition are more likely to be excellent ruthenium organometallic compounds for forming ruthenium thin films.

Therefore, ruthenium organometallic compounds suitable for the above conditions are required.

Patent Document 1: Domestic Patent Publication No. 10-0958332 Patent Document 2: Japanese Patent Publication No. 2012-0120182

The present invention is advantageous for forming ruthenium thin films as described above, and has improved thermal stability, is liquid not only at room temperature but also at low temperatures, enabling a stable supply of ruthenium compounds necessary for the ruthenium thin film formation process, and also provides high-quality ruthenium easily even at low temperatures. The purpose is to provide a novel ruthenium organometallic compound capable of producing thin films and a method for producing the same.

In order to achieve the above object, the present invention provides a ruthenium organometallic compound of the following formula (1).

[Formula 1]

In Formula 1, R1 and R2 are each a straight-chain or branched alkyl group having 1 to 4 carbon atoms, and are preferably a methyl group.

Additionally, the present invention provides a method for producing a ruthenium organometallic compound comprising the following steps. The following production method is for the case where R1 and R2 in the ruthenium organometallic compound of Formula 1 are each a methyl group.

The ruthenium organometallic compound of the present invention has thermal stability and liquid properties at room temperature, making it possible to easily produce high-quality ruthenium thin films even at low temperatures. In addition, the ruthenium compound can be supplied to the ruthenium thin film process even in winter due to its liquid properties not only at room temperature but also at low temperatures. There is an advantage in that stable supply is possible without the need for separate devices such as thermal insulation, that is, excellent handling during supply.

Figure 1 shows the NMR of the product of step 1 in Example 1 of the method for producing the ruthenium organometallic compound of the present invention.
Figure 2 is the NMR of the product of step 2 in Example 1 of the method for producing the ruthenium organometallic compound of the present invention.
Figure 3 is an NMR of the ruthenium organometallic compound represented by Chemical Formula 1 of the present invention, which is the product of step 3 in Example 1 of the method for producing the ruthenium organometallic compound of the present invention.
Figure 4 is the TGA DATA of the ruthenium organometallic compound of Example 1 of the present invention and the comparative example.
Figure 5 is a differential scanning calorimetry analysis comparison table (DSC) at high temperature of the ruthenium organometallic compound of Example 1 of the present invention and the comparative example.
Figure 6 is a differential scanning calorimetry analysis comparison table (DSC) at low temperature of the ruthenium organometallic compound of Example 1 of the present invention and the comparative example.
Figure 7 is a photograph showing a ruthenium thin film formed by the ruthenium organometallic compound of the present invention.
Figure 8 is NMR of Rudense, a comparative example.

The present invention relates to a ruthenium organometallic compound represented by the following formula (1).

[Formula 1]

In Formula 1, R1 and R2 are each a straight-chain or branched alkyl group having 1 to 4 carbon atoms, and are preferably a methyl group.

The method for producing the ruthenium organometallic compound represented by Formula 1 of the present invention includes the following steps. The following production method is for the case where R1 and R2 in the ruthenium organometallic compound of Formula 1 are each a methyl group.

Specifically, in step 1, a mixture of anhydrous alcohol injected into ruthenium (III) chloride divided in an anhydrous state is cooled to -40°C to -30°C, and the temperature of the cooled mixture is maintained at the cooling temperature. While injecting diethylcyclopentadiene. After adding zinc while maintaining the temperature of the mixture at the above cooling temperature, the temperature of the reactant is gradually raised to room temperature and the reaction proceeds while stirring. After the reaction is over, the salt is removed through a filter, washed with a solvent, and distilled under reduced pressure to obtain liquid bis(η ⁵ -diethylcyclopentadienyl)ruthenium.

The ruthenium(III) chloride:diethylcyclopentadiene is used in a 1:3 (molar ratio), and the zinc is used in an amount of 1.1 to 1.3 (molar ratio) based on the amount of ruthenium(III) chloride used.

The anhydrous alcohol is an alcohol having 1 to 4 carbon atoms, preferably methanol or ethanol, and the washing solvent is an aromatic organic solvent, preferably toluene.

In step 2, [tris(acetonitrile)(η ⁵ -diethylcyclopentadienyl)ruthenium(II)][tetrafluorocarbon from bis(η ⁵ -diethylcyclopentadienyl)ruthenium obtained in step 1. This is the step of manufacturing [borate].

Specifically, the mixture of bis(η ⁵ -diethylcyclopentadienyl)ruthenium obtained in step 1 in an anhydrous organic solvent is cooled to 0°C, and then tetrafluoroborate diethyl ether complex is added. Afterwards, the reaction temperature was raised to room temperature and stirred to cause the reaction. After the stirring reaction, the solvent was removed under reduced pressure, and the obtained liquid material was washed with ether solvent and dried to form a liquid compound [tris(acetonitrile)(η ⁵ -diethylcyclopentadienyl)ruthenium(II)][Tetsura fluoroborate].

The amount of the tetrafluoroboric acid diethyl ether complex used is 1.1 to 1.3 (molar ratio) times that of bis(η ⁵ -diethylcyclopentadienyl)ruthenium. The anhydrous organic solvent is a nitrile-based solvent, preferably MeCN. The washing solvent is an ether having 1 to 3 carbon atoms, preferably diethyl ether.

Step 3 is a step of obtaining the ruthenium organometallic compound of the present invention, [Tris(acetonitrile)(η ⁵ -diethylcyclopentadienyl)ruthenium(II), a borate salt compound of tris(nitrile) obtained in step 2. )] [Tetrafluoroborate] is mixed with mesityl oxide, an enone derivative, in the presence of a base, heated and reacted, concentrated under reduced pressure, extracted with a non-polar solvent, and the extracted solvent is concentrated and distilled to obtain liquid (η ⁵ - Obtain 2,4-dimethyl-1-oxa-2,4-pentadienyl)(η ⁵ -diethylcyclopentadienyl)ruthenium.

The amounts of mesityl oxide and base, which are enone derivatives, are respectively 30 to 40 times (molar ratio) and 3 to 6 times (molar ratio) times the borate salt compound of tris (nitrile) obtained in step 2.

Additionally, the heating temperature is 50°C to 90°C, and the nonpolar solvent is a hydrocarbon organic solvent having 5 or more carbon atoms, and is preferably hexane.

In the case where R1 and R2 of Formula 1, which are the ruthenium organometallic compounds of the present invention, are each straight or branched chain having 2 to 4 carbon atoms other than the methyl group, in step 3, as an enone derivative, R1 and R2 of Formula 1 each have carbon atoms. Corresponding compounds that can be prepared with 2 to 4 straight or branched chains are used. For example, when R1 and R2 are each t-Bu, 2, 2, 5, 6, 6-pentamethylhepta-4-en-3-one is used as the enone derivative.

As described above, the ruthenium organometallic compound represented by Formula 1 of the present invention is a stable liquid at room temperature, is thermally stable, and has good volatility, making it a compound suitable for the ruthenium thin film process of chemical vapor deposition or atomic layer deposition (Figures 6 and 7 reference).

The present invention can be better understood by the following examples, which are for illustrative purposes only and are not intended to limit the scope of protection defined by the appended claims.

In addition, the present invention is not limited to the following examples, and various modifications and implementations are possible without departing from the gist of the present invention as claimed in the claims.

Example 1: (η of Formula 1) ⁵ -2,4-dimethyl-1-oxa-2,4-pentadienyl) (η ⁵ -Manufacture of diethylcyclopentadienyl)ruthenium

(η ⁵ -2,4-dimethyl-1-oxa-2,4-pentadienyl)(η ⁵ -diethylcyclopentadienyl)ruthenium of Formula 1 of the present invention is obtained from steps 1 to 3 below. obtained.

<step 1: Ru(Et ₂ Cp) ₂ ; {Production of bis(η ⁵ -diethylcyclopentadienyl)ruthenium}>

30.0 g (145 mmol) of ruthenium(III) chloride was distributed in a 250 mL Shrink flask in a glove box, then 238 g of absolute ethanol was injected and cooled to -35 to 30°C. Inject 53g (434mmol) of diethylcyclopentadiene into the cooled solution and add zinc to the flask, paying attention to the temperature rise. After injection, the reaction mixture was slowly warmed to room temperature and stirred for 12 hours. The reaction mixture was filtered through Celite filter and washed with toluene. The solvent in the filtrate was removed using a vacuum rotary concentrator, dissolved again in toluene, and then filtered through a silica gel filter. The solvent in the filtrate was again removed and distilled under reduced pressure to obtain 39.8 g (yield 80%) of the title compound, a yellow liquid compound.

The NMR data of the obtained title compound is shown in Figure 1.

<step 2: [Ru(Et ₂ Cp)(MeCN) ₃ ]BF ₄ ; [Tris(acetonitrile)(η ⁵ -Manufacture of diethylcyclopentadienyl)ruthenium(II)][tetrafluoroborate]>

Add Ru(Et ₂ Cp) ₂ (100.26 g, 292 mmol) and anhydrous MeCN (1653.55 g) to a dried 3-neck shrink flask and cool to 0°C. HBF ₄ -Et ₂ O (54.36 g) was added dropwise to the cooled reaction mixture and stirred for 30 minutes. Afterwards, the reaction temperature was slowly raised to room temperature and stirred for 24 hours. After completely removing the solvent under reduced pressure, the resulting liquid was washed with Et ₂ O several times and completely dried to obtain 94.90 g (75% yield) of the title compound, a brown liquid compound.

The NMR data of the obtained title compound is shown in Figure 2.

<step 3: (η ⁵ -2,4-dimethyl-1-oxa-2,4-pentadienyl) (η ⁵ -Manufacture of diethylcyclopentadienyl)>

Add [Ru(Et ₂ Cp)(MeCN) ₃ ]BF ₄ (94.90 g) to the dried flask and dissolve it in mesityl oxide (861.97 g). Li ₂ CO ₃ (81.12 g) was added to the reaction mixture solution and stirred at room temperature for 30 minutes. Afterwards, the reaction temperature was raised to 80°C and stirred for 12 hours. After completely removing the solvent under reduced pressure, the resulting liquid is extracted several times with hexane solvent, filtered through Celite, and dried. After drying, the obtained liquid was distilled under reduced pressure to obtain 35.69 g (51% yield) of the title compound as a reddish-brown liquid.

NMR data for the title compound of the present invention, the compound of Formula 1, is shown in Figure 3.

Comparative example: (η ⁵ -2,4-dimethyl-1-oxa-2,4-pentadienyl) (η ⁵ -Manufacture of ethylcyclopentadienyl)ruthenium (‘Rudense’)

The above compound as a comparative example is (η ⁵ -2,4-dimethyl-1-oxa-2,4-pentadienyl) (η ⁵ -ethylcyclopentadienyl)ruthenium.

Rudense, the compound of the comparative example, was prepared in the same manner as Example 1, except that diethylcyclopentadiene was replaced with monoethylcyclopentadiene in step 1 of Example 1.

The compound of the comparative example prepared above was obtained in liquid form by vacuum distillation, and then changed to solid form after a certain period of time at room temperature.

Rudense, the compound in the comparative example, is a ruthenium organometallic material that is generally widely applied in ALD/CVD processes.

NMR data for Rudense, a compound obtained in the comparative example, is shown in Figure 8.

Example 2: Thermogravimetric testing of ruthenium compounds

(2,4-dimethyloxopentadieneyl)(diethylcyclopentadienyl)Ru, a ruthenium organometallic compound represented by Formula 1 of the present invention in Example 1, and Rudense, a compound in Comparative Example, were each analyzed using TGA (thermogravimetric analysis). In the TGA test, the test object was analyzed while raising the temperature to 500°C at a rate of 10°C/min, and the TGA graph and results are shown in Figure 4 and Table 1 below.

Compound name Comparative example
(Rudense) Example 1
(Compound of Formula 1 of the present invention) T _1/2 ℃ 219.8℃ 228.7℃ Residual Mass (%) 12.2% 6.5%

From the TGA graph in Table 1 and Figure 4, the newly synthesized ruthenium organometallic compound of Chemical Formula 1 of the present invention shows a temperature at which its weight is reduced by half (T _1/2 °C), which is significantly higher than that of Rudense in the comparative example. In addition, the newly synthesized ruthenium organometallic compound of Chemical Formula 1 of the present invention appears to have a Residual Mass value significantly lower than that of the Comparative Example, so the ruthenium organometallic compound of Chemical Formula 1 of the present invention has thermal stability compared to Rudense, the ruthenium compound of the Comparative Example. It can be seen that this is an improved ruthenium compound.

Due to this high thermal stability, the ruthenium organometallic compound of Chemical Formula 1 of the present invention has the advantage of being able to stably form a ruthenium film not only at low temperatures but also in high temperature deposition processes.

Example 3: Differential scanning calorimetry analysis experiment of ruthenium compounds

(2,4-dimethyloxopentadieneyl)(diethylcyclopentadienyl)Ru, a ruthenium organometallic compound represented by Formula 1 of the present invention in Example 1, and Rudense, a compound of Comparative Example, were subjected to differential scanning calorimetry (DSC) at high and low temperatures, respectively. analyzed.

In the DSC test, the ruthenium organometallic compound of Formula 1 of the present invention in Example 1 and Rudense, a compound of Comparative Example, were analyzed while raising the temperature to 400°C at a rate of 10°C/min.

The results are shown in Figures 5 and 6 and Table 2.

Compound name Comparative example Example 1 T _{(dec, start)} ℃ 170℃ 200℃ T _{(dec max)} ℃ 292℃ 303℃

From the DSC graph in Table 2 and Figure 6, Rudense, the compound of the comparative example, is shown to have a melting point in the above temperature range with a strong peak at about 20°C to 30°C, and the compound of the comparative example exists as a solid in the above temperature range. On the other hand, it can be seen that the ruthenium organometallic compound of the present invention represented by Chemical Formula 1 of Example 1 exists in a liquid state as no peak appears in the above temperature range (see FIG. 6). As described above, the ruthenium organometallic compound of Formula 1 of the present invention has the advantage of not generating a freezing point (cold spot) that can be generated when the ruthenium compound supplied to the deposition process is vaporized in a liquid state not only at room temperature but also at low temperature. As a result, it is possible to supply a stable ruthenium compound to the ruthenium thin film process, which has the advantage of not requiring a separate heating device in the ruthenium compound supply piping line.

In addition, the thermal decomposition behavior of the ruthenium organometallic compound of the present invention represented by Chemical Formula 1 in Example 1 appears to start at a higher temperature than that of Rudense in Comparative Example (see FIG. 5). The high thermal decomposition temperature of the ruthenium organometallic compound represented by Formula 1 in Example 1 of the present invention indicates that the ruthenium organometallic compound represented by Formula 1 of the present invention is a ruthenium compound with improved thermal stability at high temperatures compared to Rudense, a comparative example compound. Able to know.

As described above, the ruthenium organometallic compound of Formula 1 of the present invention has thermal stability and can be stably supplied to the ruthenium thin film formation process in a liquid state not only at room temperature but also at low temperature, which is advantageous for forming a ruthenium thin film.

Example 4: Thin film formation process of ruthenium organometallic compound of the present invention

<Tabernacle test>

Using the ruthenium organometallic compound of the present invention as a raw material, a ruthenium thin film was formed using a CVD device. Film formation conditions, processes, and results are as follows.

go. Tabernacle formation conditions

- Substrate: SiO2 substrate

- Substrate temperature: 370℃

- Sample temperature (vaporization temperature): 74℃

- Chamber pressure: 5 Torr

- Reactive gas: ammonia

- Sample and reactive gas injection time: 60min

- Reactive gas injection amount: ammonia 500 mL/min

me. Film formation process and results

A ruthenium thin film was formed by injecting the ruthenium organometallic compound of the present invention and the reactive gas ammonia for a certain period of time under the film formation conditions described above, and the thin film deposition rate of the film was constant at 0.4 Å/min. This confirms that the novel ruthenium organometallic compound of the present invention undergoes uniform CVD growth. In addition, the film thickness of the ruthenium thin film was measured using a transmission electron microscope (TEM), and the film thickness of the ruthenium thin film was 24 Å (see Figure 7).

Above, the present invention has been described in detail with preferred embodiments, but the present invention is not limited to the above embodiments, and various modifications can be made by those skilled in the art within the scope of the technical idea of the present invention. possible.

Claims (4)

A ruthenium organometallic compound, characterized in that represented by the following formula (1):
[Formula 1]

In Formula 1, R1 and R2 are each a methyl group. delete A method of forming a ruthenium thin film, characterized by using the ruthenium organometallic compound of claim 1. In claim 3,
A method of forming a ruthenium thin film, characterized in that the process of the thin film forming method is chemical vapor deposition (CVD) or atomic layer deposition (ALD).