JP3511228B2 - Ethylcyclopentadienyl (1,5-cyclooctadiene) iridium, method for producing the same, and method for producing iridium-containing thin film using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to ethylcyclopentadienyl (1,5-cyclooctadiene) iridium (C ₂ H ₅ C ₅ H ₄ ) Ir (C ₈ H ₁₂ ), a method for producing the same, and a method for producing the same. The present invention relates to a method for producing an iridium-containing thin film by a chemical vapor deposition method (hereinafter referred to as a CVD method).

[0002]

2. Description of the Related Art In recent years, with high integration of ULSI, a high dielectric constant (Ba, Sr) TiO ₃ thin film and a ferroelectric Pb (Zr, Ti) O ₃ thin film have been developed as capacitors. As this electrode, Ir and / or I
rO ₂ thin films have been investigated. The preparation of the Ir film, sputtering of Ir metal is used often, IrO
_Although reactive sputtering of Ir metal is often used as a method for manufacturing the ₂ thin film, the CVD method is expected as a measure for step coverage and mass productivity in the case of further miniaturization. As the volatile Ir compound used in the CVD method, tris (dipivaloylmethanato) iridium Ir is used.
_{(Dpm) 3} and tris (acetylacetonato) iridium Ir _{(acac) 3} and cyclopentanone dienyl (1,
5-Cyclooctadiene) iridium (C ₅ H ₅ ) Ir
(C ₈ H ₁₂ ) and methylcyclopentadienyl (1,5
- cyclooctadiene) iridium _{(CH 3} C _{5 H} 4)
Ir (C ₈ H ₁₂ ) and the like are being studied.

In the proceedings of the 42nd Joint Lecture Meeting on Applied Physics in Spring 1995, p491,30-p-D-14 (Nakabayashi et al.), Ir (dpm) ₃ was used as a raw material in the CVD method, and 500. It is disclosed that an Ir film is formed on a Si substrate at ˜600 ° C. and then heat-treated at 600 ° C. in air to obtain IrO ₂ . However, Ir (dpm) ₃ has a melting point of 2
It is a solid crystal at room temperature of 35 ° C., the vapor pressure of 0.1 Torr is around 150 ° C., and it is supplied by sublimation.

Proceedings of the 56th Autumn Meeting of the Applied Physics Society of Japan p400, 27p-ZG-3 (Otsuki et al.)
Discloses that Ir (acac) ₃ is used as a raw material by a CVD method and IrO ₂ is deposited on a MgO substrate at 400 ° C. However, Ir (acac) ₃ has a melting point of 2
It is a solid crystal at room temperature of 69 ° C., the vapor pressure of 0.1 Torr is around 180 ° C., and it is supplied by sublimation.

J. B. Hoke, E .; W. Stern
and H.D. H. Murray, J .; Mater. Ch
em. Vol. The 1,551 (1991), was maintained at _{95 ℃ (C 5 H 5)} Ir (C 8 H 12) or _(CH 3 _{C 5}
It is disclosed that a vapor of H ₄ ) Ir (C ₈ H ₁₂ ) is caused to be accompanied by hydrogen gas and a film of iridium metal containing 1 atomic% or less of carbon is formed on a fused silica substrate at 120 ° C. by a CVD method. Further, (C ₅ H ₅ ) Ir kept at 80 ° C.
(C ₈ H ₁₂ ) and (CH ₃ C ₅ H ₄ ) Ir (C
It is disclosed that a vapor of ₈ H ₁₂ ) is oxidized under an oxygen partial pressure of 1.3 Torr and a film of iridium containing 1 atomic% or less of carbon and oxygen is formed on a substrate at 270 ° C. by a CVD method.

In US Pat. No. 5,130,172, vapor of an organometallic compound represented by L _n MR _m obtained by heating at 100 ° C. or lower is exposed to a heated substrate at 190 ° C. or lower, and then,
A process of coating a metal film by exposing the organic metal to hydrogen at 100 ° C. or lower and reacting the hydrogen with the hydrogen is disclosed. Here, in L _n MR _m , L is hydrogen,
Ethylene, allyl, methylallyl, butadienyl, pentadienyl, cyclopentadienyl, methylcyclopentadienyl, cyclohexadienyl, hexadienyl,
Cycloheptatrienyl, or a derivative thereof having at least one alkyl side chain having less than 5 carbon atoms, M is capable of easily cycling between two oxidation states, and has a hydrocarbon ligand as a catalyst water. Represents a metal that can be added,
R represents methyl, ethyl, propyl, butyl, n
Is an integer from 0 to the valence of the metal, m is an integer from 0 to the valence of the metal, and (n + m) is the valence of the metal. The Ir compounds described in the claims specifying the compound names are triaryliridium (C ₃ H ₅ ) ₃ Ir, cyclopentadienyl (hexadiene) iridium (C ₅ H
_{5) Ir (C 6 H 10} ), cyclopentanone dienyl (cyclohexadiene) iridium _{(C 5 H 5) Ir (} C 6 H
₈ ), pentamethylcyclopentadienyl iridium bis (ethylene) (C ₅ (CH ₃ ) ₅ ) Ir (C ₂ H ₄ ).
It is ₂ .

Among the above compounds, the melting point is in the literature Di
motionary of Organometalli
c Compounds, Vol. 2 (2nd Ed.
Table 1 is a list of those described in 1996, Chapman & Hall) and the like. As can be seen from Table 1, all compounds are solid at room temperature 25 ° C.

[0008]

[Table 1]

In the CVD method, the method of supplying the raw material compound by sublimation is inferior in quantitativeness, controllability, and mass productivity to the method of supplying by liquid or the method of supplying by evaporation of liquid by bubbling a carrier gas. . In addition, if it can be heated to form a liquid, it can be supplied by evaporation, so the controllability is considerably improved. However, there are still restrictions on the methods and devices that can be used as compared with the case of using a compound that is liquid at room temperature. Therefore, a raw material compound that is liquid at room temperature and has a sufficient vapor pressure when heated is required. However, a compound capable of forming an Ir thin film by the CVD method, liquid at room temperature of 25 ° C., and having a vapor pressure is not known.

[0010]

The problem to be solved by the present invention discloses a compound which is liquid at room temperature of 25 ° C. and has a sufficient vapor pressure when forming an Ir or IrO ₂ thin film by a CVD method. , CVD using it, Ir, IrO
₂ to provide a method of making a thin film. Another object is to provide a method for producing the compound.

[0011]

The present inventor has studied synthesis of organometallic compounds and CVD using the same for many years. In order to solve the above problems, to synthesize a non-known ethylcyclopentadienyl (1,5-cyclooctadiene) iridium _{(C 2 H 5 C 5 H} 4) Ir (C 8 H 12), was purified, The melting point and vapor pressure were measured to find that they have favorable physical properties. Further, using them, CVD was carried out to obtain Ir, IrO ₂
When a film was made, it was found that a stable and good film was obtained, and the present invention was completed. That is, according to the present invention, the room temperature 2 for forming the Ir, IrO ₂ film by the CVD method is used.
As a liquid raw material at 5 ° C., ethylcyclopentadienyl (1,5-cyclooctadiene) iridium (C ₂ H ₅
This is due to the finding of C ₅ H ₄ ) Ir (C ₈ H ₁₂ ).

[0012]

The compounds of the present invention DETAILED DESCRIPTION OF THE INVENTION ethyl cyclopentadienyl (1,5-cyclooctadiene) iridium _{(C 2 H 5 C 5 H} 4) Ir (C 8 H 12). The present invention is a method for producing the above compound, which is excellent in mass productivity.
The prototype is J. B. Hoke, E .; W. Stern
and H.D. H. Murray, J .; Mater. Ch
em. Vol. It is a method for synthesizing methylcyclopentadienyl (1,5-cyclooctadiene) iridium disclosed in 1,551 (1991). It in THF, bis (1,5-cyclooctadiene chloro iridium)
[(C ₈ H ₁₂ ) IrCl] ₂ and sodium methylcyclopentadienide Na (CH ₃ C ₅ H ₄ ) were reacted by stirring at −78 ° C. at room temperature, recovered, and sublimated to obtain an Ir yield of 81%. And methylcyclopentadienyl (1,5-cyclooctadiene) iridium (CH ₃ C
It is disclosed that ₅ H ₄ ) Ir (C ₈ H ₁₂ ) is obtained.

The present inventor, in the method of Hoke et al.
If sodium ethylcyclopentadienide is used instead of sodium methylcyclopentadienide and the reaction is carried out under similar conditions, the desired ethylcyclopentadienyl (1,5-cyclooctadiene) iridium (C ₂ H ₅
C ₅ H ₄₎ found _{that Ir} (C _{8 H 12)} is obtained.

After the reaction, the THF solvent was distilled off under reduced pressure, the target substance was extracted from the resulting viscous product with hexane, the hexane was distilled off under reduced pressure, and the residue was vacuum distilled (105 ° C /
A light yellow liquid (0.3 Torr) was obtained. This liquid was analyzed by Ir content analysis, CH analysis and ¹ H-NMR analysis to obtain ethylcyclopentadienyl (1,5-cyclooctadiene) iridium (C ₂ H ₅ C ₅ H ₄ ) Ir (C ₈
H ₁₂ ). It has a melting point of 14 ° C. and is a liquid that is easily supercooled, and its viscosity at room temperature is about 20 cP. Stable in air and difficult to react with water. It has high thermal stability, and according to TG-DTA under 1 atmosphere of Ar atmosphere, it is 10 at 260 ° C.
Evaporated 0%.

The present invention is a highly pure ethylcyclopentadienyl (1,5-cyclooctadiene) iridium (C ₂ H ₅ C ₅ H ₄ ) Ir which can be used as a raw material for electronic materials.
It is also a method of synthesizing (C ₈ H ₁₂ ).

The present invention is directed to ethylcyclopentadienyl (1,5-cyclooctadiene) iridium (C ₂ H ₅
C ₅ H ₄ ) Ir (C ₈ H ₁₂ ) is used to form I by the CVD method.
It is also a method of forming an r-containing thin film. 80 to this compound
An Ir thin film can be formed by keeping the temperature at about 150 ° C., bubbling a carrier gas in this solution under reduced pressure to evaporate it, sending it into a thermal decomposition reactor, and thermally decomposing it on a substrate at 100 to 500 ° C. in a hydrogen atmosphere. Also, during low oxygen partial pressure 25
An Ir thin film can be formed by thermal decomposition on a substrate at 0 to 500 ° C. Instead of bubbling and evaporating and supplying, a method of supplying and evaporating by a liquid mass flow controller is also possible.

The first method of forming an Ir thin film in the present invention is a method of thermally decomposing on a substrate at 100 to 500 ° C. in a hydrogen atmosphere. The Ir thin film obtained in a hydrogen atmosphere is
A metal film with a clean mirror surface and low carbon uptake.
The IrO ₂ thin film can be obtained by thermal decomposition at 550 ° C. or higher in the presence of oxygen gas, or by forming an Ir thin film and then heat-treating at 550 ° C. or higher in an atmosphere containing oxygen.

The second method of forming an Ir thin film in the present invention is a method of thermally decomposing on a substrate at 250 to 500 ° C. in a low pressure oxygen atmosphere. Ir obtained under low pressure oxygen atmosphere
The thin film is a metal film with a clean mirror surface and little uptake of carbon and oxygen. This method is convenient when depositing a film on a compound that dislikes a reducing atmosphere.

[0019]

Example 1 Ethylcyclopentadienyl (1,5-cyclooctadiene) iridium (C ₂ H ₅ C ₅ H ₄ ) I
Production of r (C ₈ H ₁₂ ) A 500 ml four-necked flask equipped with a reflux condenser, a thermometer, a dropping funnel, and a stirring blade was vacuum-replaced to an argon atmosphere and charged with 350 ml of THF, then,
Bis (1,5-cyclooctadienechloroiridium)
[(C ₈ H ₁₂ ) IrCl] ₂ 16.8 g (25.0 m
(mol) was charged and dissolved. -7 this reaction flask
After cooling to 8 ° C. and stirring, sodium ethylcyclopentadienide Na (C ₂ H ₅ C
₅ H ₄ ) 7.2 g (62.0 mmol) in THF solution 3
1 ml was added. After stirring at −78 ° C. for 30 minutes, the temperature was gradually raised to room temperature, and the mixture was stirred at room temperature for 30 minutes. Then, the solvents are distilled off under reduced pressure, and the remaining viscous substance is diluted with hexane (300).
ml was added and dissolved. Remove a small amount of precipitate by filtration,
Hexane was distilled off, and vacuum distillation was performed at about 0.3 Torr.
Obtained was 5.2 g. This liquid was identified by the following identification as ethylcyclopentadienyl (1,5-cyclooctadiene) iridium (C ₂ H ₅ C ₅ H ₄ ) Ir (C
₈ H ₁₂ ), corresponding to 38.6 mmol , yield 7
It was 7%.

Identification (1) Ir analysis value 50.8 wt% (theoretical value 48.84 wt%) (2) CH analysis C45.36 wt% H5.42 wt% (theoretical value C45.78 wt% H5.38 wt%) (3) ¹ H-NMR apparatus BRUKER AC300P (300 MHz) solvent CD ₂ Cl ₂ method 1D spectrum and attribution δ _H (ppm) proton number attribution 1.15 3H CH ₃ ; Et 1.76 4H CH ₂ ; Cycloadenee 2.04 4H CH ₂ Cycloaddiene 2.25 2H CH ₂ ; Et 3.58 4H CH; Cycloaddiene 4.99 to 5.32 4H CH; Cyclopentadienyl

Physical properties and purity (4) Melting point 14 ° C. Easy to supercool (5) Vapor pressure 100-110 ° C./0.3 Torr (6) Density about 1.5 g / cm ³ (7) Viscosity about 20 cP (room temperature) ( 8) Reactivity Stable without reacting with air and water (9) Thermal stability Stable at 150 ° C (10) TG-DTA measurement conditions; Arl pressure, sample weight 12.67 mg,
Temperature rising rate 10.0 deg / min Result; weight loss starts at about 120 ° C, 50 at 240 ° C
%, 100% reduction at 260 ° C. (11) Purity impurity analysis value (unit: ppm) Fe 1, Al <1, Si 3, Na <1, Ca
1, It was highly pure as described above.

[0022]

EXAMPLE 2 Ethyl cyclopentadienyl (1,5-cyclooctadiene) iridium _{(C 2 H 5 C 5 H} 4) I
Production of pure Ir thin film by CVD method using r (C ₈ H ₁₂ ). The entire system of the raw material container and the pyrolysis reactor was kept at a reduced pressure of 10 Torr by a rotary vacuum pump and a pressure control valve.
Ethylcyclopentadienyl (1,5-cyclooctadiene) iridium _{(C 2 H 5 C 5 H} 4) Ir (C 8 H
₁₂ ) A raw material container filled with 13 g was placed in a constant temperature bath at 100 ° C., a carrier gas Ar was bubbled at 10 sccm, and ethyl cyclopentadienyl (1,5-
Cyclooctadiene) iridium was evaporated and introduced into the pyrolysis reactor. At the same time, 100 sccm of hydrogen gas was also introduced into the thermal decomposition reactor. 400 in the pyrolysis reactor
A quartz substrate heated to ℃ was set, ethylcyclopentadienyl (1,5-cyclooctadiene) iridium was decomposed on this substrate, and a pure Ir thin film was formed.
It was formed to a thickness of 50 nm in 5 minutes. It was identified as metal Ir by XRD. The film was dissolved and analyzed for metallic impurities by ICP emission spectrometry, but metallic impurities other than Ir were not detected.

[0023]

EXAMPLE 3 ethylcyclopentadienyl (1,5-cyclooctadiene) iridium _{(C 2 H 5 C 5 H} 4) I
Production of pure Ir thin film by CVD method using r (C ₈ H ₁₂ ). The entire system of the raw material container and the pyrolysis reactor was kept at a reduced pressure of 10 Torr by a rotary vacuum pump and a pressure control valve. Ethylcyclopentadienyl (1,5-cyclooctadiene) iridium _{(C 2 H 5 C 5 H} 4) Ir (C
₈ H ₁₂ ) 13 g of the raw material container was placed in a constant temperature bath at 100 ° C., a carrier gas Ar was bubbled at 10 sccm, and ethyl cyclopentadienyl (1,
5-cyclooctadiene) iridium is vaporized and entrained,
It was introduced into the pyrolysis reactor. 20 sccm oxygen gas at the same time
Was also introduced into the pyrolysis reactor. 300 in pyrolysis reactor
A quartz substrate heated to ℃ was set, ethylcyclopentadienyl (1,5-cyclooctadiene) iridium was decomposed on this substrate, and a pure Ir thin film was converted into 3
It was formed to a thickness of 60 nm in 0 minutes. It was identified as metallic Ir by XRD. The film was dissolved and analyzed for metallic impurities by ICP emission spectrometry, but metallic impurities other than Ir were not detected.

[0024]

Example 4 Ethylcyclopentadienyl (1,5-cyclooctadiene) iridium (C ₂ H ₅ C ₅ H ₄ ) I
Production of Pure IrO ₂ Thin Film by CVD Method Using r (C ₈ H ₁₂ ). In Example 3, when the pure Ir thin film formed was placed in an oxygen atmosphere at 600 ° C., it became an IrO ₂ thin film. Identification is XR
I went in D.

[0025]

EFFECT OF THE INVENTION The ethylcyclopentadienyl (1,5-cyclooctadiene) iridium (C ₂ H ₅
C ₅ H ₄ ) Ir (C ₈ H ₁₂ ) is a liquid at room temperature,
Since it has a sufficient vapor pressure near 00 ° C, it can be quantitatively supplied as a CVD raw material by gas bubbling or a liquid mass flow controller, and can be thermally decomposed onto the substrate.
An r-containing thin film can be formed. According to the present invention, a thin film of pure Ir or IrO ₂ can be formed by a CVD method having excellent mass productivity.

Claims (3)

(57) [Claims] 1. Ethylcyclopentadienyl (1,5-
Cyclooctadiene) iridium. 2. A method for producing ethylcyclopentadienyl (1,5-cyclooctadiene) iridium by reacting bis (1,5-cyclooctadienechloroiridium) with sodium ethylcyclopentadienide in a solvent. 3. A method for producing an iridium-containing thin film by chemical vapor deposition, wherein a heated substrate is brought into contact with ethylcyclopentadienyl (1,5-cyclooctadiene) iridium to produce an iridium-containing thin film. Method.