JP2010215982A - Method for producing ruthenium-containing film using ruthenium complex organic solvent solution, and ruthenium-containing film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a ruthenium-containing film using (cyclopentadienyl) (2, 4-dimethylpentadienyl) ruthenium with a high melting point, or bis-(2, 4-dimethylpentadienyl) ruthenium. <P>SOLUTION: The ruthenium-containing film is produced by using an organic solvent solution of (cyclopentadienyl) (2, 4-dimethylpentadienyl) ruthenium or bis-(2, 4-dimethylpentadienyl) ruthenium as a raw material. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a ruthenium complex useful for forming a ruthenium-containing film by a chemical vapor deposition method (hereinafter referred to as a CVD method), an atomic layer deposition method (hereinafter referred to as an ALD method), or the like. The present invention relates to a method for producing a ruthenium-containing film using a solution, and a ruthenium-containing film.

In recent years, a dielectric material having a large relative dielectric constant has been actively studied in order to enable higher integration and higher density in recent integrated circuits. Specifically, Ta ₂ O ₅ or BST ((Ba, Sr) TiO ₃ ) or the like has been studied as a capacitor material, and noble metal thin films such as ruthenium, platinum and iridium, or these noble metals are used as the electrode material of these capacitors. The oxide thin film is required. In particular, ruthenium and ruthenium oxide are attracting attention as the center of future electrode materials. As a method for producing ruthenium and a ruthenium oxide thin film, a sputtering method, a CVD method, or an ALD method is used. In particular, film forming methods involving chemical reactions of metal compounds such as CVD and ALD methods are easy to manufacture a uniform film and have excellent step coverage (step coverage), so that they can be applied to circuits and electronic members in recent years. It is considered that it will become the mainstream of the future thin film electrode manufacturing process because it can cope with higher density of the electrode.

  As a raw material for forming a thin film by using this CVD method or ALD method, among metal compounds, an organometallic compound that is easy to handle is considered suitable. Conventionally, ruthenocene derivatives or tris (dipivaloylmethanato) ruthenium derivatives have been used as organometallic compounds for producing ruthenium-containing films such as metal ruthenium or ruthenium oxide. Ruthenocene derivatives have a sandwich structure in which each cyclopentadiene ring comprises only carbon and hydrogen, and ruthenium is sandwiched between two cyclopentadiene rings. Although this ruthenocene is highly stable in the atmosphere and has no toxicity, it is suitable as a raw material for CVD and ALD, but basically has a sandwich structure. Since this structure is extremely stable, The decomposition temperature is high, and the substrate temperature at the time of film formation must be increased. Patent Document 1 discloses bis (alkylcyclopentadienyl) ruthenium represented by bis (ethylcyclopentadienyl) ruthenium and bis (isopropylcyclopentadienyl) ruthenium as a ruthenocene derivative. Patent Document 2 discloses the use of alkyl-substituted ruthenocene as a CVD material.

  On the other hand, a synthesis example of a complex having a half sandwich structure in which one of the two ligands is a linear pentadienyl group is reported in Non-Patent Document 1, (cyclopentadienyl) There is (2,4-dimethylpentadienyl) ruthenium. However, this complex has a very high melting point of 136 to 137 ° C., which is neat regardless of whether the raw material supply system of the CVD or ALD film forming apparatus is a bubbling method or a liquid vaporization supply system (vaporizer). It is not preferable as a material to be used.

  In Patent Document 3, as an attempt to lower the melting point of a complex having a half sandwich structure, an alkyl group is bonded to a cyclopentadienyl group, and a half sandwich structure ruthenium complex which is liquid at room temperature is reported. Has been. However, alkyl-substituted cyclopentadiene, which is a raw material for half-sandwich structure ruthenocene, is not only expensive and industrially disadvantageous, but also increases the molecular weight due to the alkyl group bond, resulting in a decrease in vapor pressure, resulting in a decrease in film formation rate. There was a problem.

  As a synthesis example of a complex having a bisopen structure having two linear pentadienyl groups as a ligand, there is bis (2,4-dimethylpentadienyl) ruthenium reported in Non-Patent Document 2. However, this complex also has a high melting point of 78 ° C., and as a material to be used neat regardless of whether the raw material supply system of a CVD or ALD film forming apparatus is a bubbling method or a liquid vaporization supply system (vaporizer). It is not preferable.

JP 11-35589 A JP 2000-281694 A JP 2003-342286 A

R. Gleiter et al. , Organometallics, 8, 298 (1989). Lothar Stahl et al. , Organometallics, Vol. 2, no. 9, P.I. 1229-1234

  The object of the present invention is to synthesize the half-open structure ruthenocene which is superior in film formation characteristics by the ALD method or the CVD method, has the smallest molecular weight, and improves the film formation speed (cyclopentadienyl). ) (2,4-dimethylpentadienyl) ruthenium can also be synthesized among bis-open structure ruthenocenes, and has the smallest molecular weight and bis (2,4- The object is to provide a method for producing a ruthenium-containing film using dimethylpentadienyl) ruthenium.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that (cyclopentadienyl) (2,4-dimethylpentadienyl) ruthenium or bis (2,4-dimethylpentadiene) that is solid at room temperature. (Ethyl) ruthenium was dissolved in an organic solvent to form an organic solvent solution, and it was found that the form could be adapted to a liquid vaporization and supply system, and further produced (cyclopentadienyl) (2,4-dimethylpentadienyl) It was found that a good quality ruthenium-containing film can be formed by forming a film using a ruthenium organic solvent solution or a bis (2,4-dimethylpentadienyl) ruthenium organic solvent solution.

  Examples of organic solvents that dissolve (cyclopentadienyl) (2,4-dimethylpentadienyl) ruthenium or bis (2,4-dimethylpentadienyl) ruthenium include alcohols such as methanol, ethanol, propanol, and isopropanol, Esters such as ethyl acetate, butyl acetate, isoamyl acetate, glycol ethers such as ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethyl ether, tertiary butyl methyl ether, glyme, diglyme, triglyme, tetrahydrofuran Ethers such as tertiary butyl methyl ketone, isobutyl methyl ketone, ethyl butyl ketone, dipropyl ketone, diisobutyl ketone, methyl amyl Tons, cyclohexanone, ketones such as acetone, hexane, cyclohexane, ethylcyclohexane, heptane, octane, benzene, toluene, can be mentioned hydrocarbons such as xylene, it is not particularly limited.

  The concentration to be diluted can be selected depending on the application. However, if the concentration is too low, the film forming rate is lowered. If the concentration is too high, (cyclopentadienyl) (2,4-dimethylpentadienyl) is used depending on the use conditions. Since ruthenium or bis (2,4-dimethylpentadienyl) ruthenium may precipitate and affect the film formation, 0.01 mol / L to 4 mol / L is preferable.

  Although there is no limitation in particular as a film-forming method, ALD method or CVD method etc. can be mentioned. Examples of the ALD method or the CVD method include a thermal ALD method, a thermal CVD method, a plasma ALD method, a plasma CVD method, a photo ALD method, and a photo CVD method.

  In the case of forming a film by the ALD method or the CVD method, as a method for supplying the raw material to the film formation chamber, bubbling or a liquid vaporization supply system can be mentioned, and the bubbling in the solution is (cyclopentadienyl) (2 , 4-Dimethylpentadienyl) ruthenium or bis (2,4-dimethylpentadienyl) ruthenium and the vapor pressure of the solvent may make it difficult to keep the film formation rate constant. A system based method is preferred.

  As a carrier gas when forming a film by the ALD method or the CVD method, a rare gas or nitrogen is preferable, and nitrogen, helium, neon, and argon are particularly preferable for economical reasons.

  Examples of the reaction gas when forming a film by the ALD method or the CVD method include hydrogen, oxygen, laughing gas, ammonia, hydrogen chloride, nitric acid gas, formic acid, and acetic acid, but are not particularly limited.

  Thus, by using the organic solvent solution of the present invention as a raw material, a ruthenium-containing film such as a metal ruthenium film, a ruthenium oxide film, or a composite film of Ru and another metal can be produced.

  According to the present invention, when a half sandwich structure ruthenium complex or a bis-open structure ruthenium complex exhibiting good film formation characteristics is used for film formation, solid (cyclopentadienyl) (2,4-dimethylpentadienyl) ruthenium is used. Bis (2,4-dimethylpentadienyl) ruthenium has been the only sublimation method that is inferior in productivity so far as a raw material supply method. However, by carrying out the present invention, a stable film formation as an organic solvent solution is possible. It can be introduced into the apparatus, and the productivity in the industrial process can be greatly improved.

It is the schematic of the CVD method film-forming apparatus used in Examples 1-4.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

Example 1 Production of Ruthenium-Containing Film by CVD Method Using Octane Solution of about 0.1 mol / L of (Cyclopentadienyl) (2,4-dimethylpentadienyl) ruthenium as a Raw Material Using the apparatus shown in FIG. As the substrate (13), a Si substrate having a SiO ₂ film of 100 nm formed on the surface thereof was used. (Cyclopentadienyl) (2,4-dimethylpentadienyl) ruthenium 26.1 g was made up to 1 L with octane to prepare an approximately 0.1 mol / L solution. This was used as a raw material (9) as a raw material container ( 10). The flow rate of the carrier gas, helium (2), was set to 398 sccm by the mass flow controller (5), the raw material feed amount was set to 1.0 g / min, and the vaporizer temperature was set to 100 ° C. by the liquid vaporization supply system (6). The raw material supply line from the liquid vaporization supply system (6) to the film forming chamber (11) was heated stepwise by a ribbon heater (17) at 120, 140, and 160 ° C. to prevent the deposition of the raw material. The mass flow controller (4) of oxygen (1) as a reaction gas was set to 2 sccm, and the line from the mass flow controller (4) to the film formation chamber (11) was heated to 160 ° C. by a ribbon heater (17) for the purpose of preheating. . The set temperature of the substrate heater (14) was 400 ° C. Film formation was carried out for 60 minutes by adjusting the pressure adjusting valve (15) and adjusting the pressure in the chamber to 10 Torr. As a result, a metallic ruthenium film having a metallic luster was formed to 45 nm.

Example 2 Production of ruthenium-containing film by CVD method using ethylcyclohexane solution of about 1 mol / L of (cyclopentadienyl) (2,4-dimethylpentadienyl) ruthenium as a raw material (cyclopentadienyl) (2, The film was formed under the same conditions as in Example 1 except that 261 g of 4-dimethylpentadienyl) ruthenium was made up to 1 L with ethylcyclohexane to prepare a solution of about 1 mol / L and used as a raw material. A metal ruthenium film was formed at 280 nm.

Example 3 Production of a ruthenium-containing film by CVD using an about 0.1 mol / L bis (2,4-dimethylpentadienyl) ruthenium octane solution as a raw material Bis (2,4-dimethylpentadienyl) ruthenium 29 .1 g was made up to 1 L with octane, and a film of about 0.1 mol / L was prepared and used as a raw material under the same conditions as in Example 1 to form a metal ruthenium film of 60 nm.

Example 4 Production of ruthenium-containing film by CVD method using ethylcyclohexane solution of about 1 mol / L bis (2,4-dimethylpentadienyl) ruthenium as a raw material 291 g of bis (2,4-dimethylpentadienyl) ruthenium A metal ruthenium film was formed at 360 nm under the same conditions as in Example 1 except that the solution was made up to 1 L with ethylcyclohexane to prepare a solution of about 1 mol / L and used as a raw material.

  The ruthenium-containing film produced using the organic solvent solution of the ruthenium complex according to the present invention can be used as a capacitor electrode material of an integrated circuit.

1. 1. oxygen gas Helium gas3. Helium gas4. 4. Mass flow controller Mass flow controller 6. 6. Liquid vaporization supply system Diaphragm valve8. Bellows seal valve9. Raw material 10. Raw material container 11. Deposition chamber 12. Shower head 13. Substrate 14. Substrate heater 15. Pressure adjustment valve 16. Vacuum pump 17. Ribbon heater

Claims (2)

A method for producing a ruthenium-containing film, characterized by using an organic solvent solution of (cyclopentadienyl) (2,4-dimethylpentadienyl) ruthenium or bis (2,4-dimethylpentadienyl) ruthenium as a raw material. A ruthenium-containing film produced by the method according to claim 1.

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