JP2009046720A - Method for producing thin film containing metal ruthenium by chemical vapor deposition technique with the use of oxygen source - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a thin film with low resistance containing metal ruthenium, which is not contaminated by ruthenium oxide and is produced by a chemical vapor deposition technique with the use of an oxygen source. <P>SOLUTION: The method for producing the thin film containing metal ruthenium by a chemical vapor deposition technique includes using: a ruthenium source that is an organic complex of ruthenium, which has β-diketonate and an unsaturated hydrocarbon compound having at least two double bonds as ligands, which is 1,5-hexadiene, 1,5-cyclooctadiene, norbornadiene, 4-vinyl-1-cyclohexene or 1,3-pentadiene, or a solvent solution thereof; and oxygen of 0.1 to 10 vol.% with respect to the total amount of gases. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a metal ruthenium-containing thin film by a chemical vapor deposition method (Chemical Vapor Deposition method; hereinafter referred to as a CVD method).

  In recent years, as a thin film electrode material for semiconductor devices such as DRAMs, use of metal ruthenium has been studied, for example, utilizing the fact that electrical characteristics such as the specific resistance value of metal ruthenium are excellent. As a method for producing these ruthenium-containing thin films, for example, film formation by the CVD method, which is easy to produce a uniform thin film, is most frequently employed, and a raw material compound suitable for the film formation is required.

  By the way, as a raw material for producing a thin film containing ruthenium atoms by a CVD method, for example, ruthenium complexes having β-diketonato or cyclopentadienyl derivatives as ligands are being widely used. A ruthenium complex having these ligands is excellent in stability and sublimation and is useful as a ruthenium source in a CVD method.

Among them, in particular, a method of obtaining a mixed film of a metal ruthenium thin film and a ruthenium oxide thin film by a CVD method by reacting a β-diketonatoruthenium complex having a diene compound as a ligand with oxygen gas at a high temperature is disclosed. (For example, see Patent Document 1 and Non-Patent Document 1). However, in these methods, by using a high-concentration oxygen gas, ruthenium oxide having an extremely high resistance value compared to metal ruthenium is inevitable and the film formation temperature is high. As a result, impurities such as carbon atoms are mixed in, thereby deteriorating the specific resistance value. Furthermore, the relationship between the oxygen concentration and the resistivity of the metal ruthenium film has not been shown.
JP 2003-306472 A J. Phys. IV France, 11, Pr3-325 (2001)

  The object of the present invention is to solve the above-mentioned problems and to provide a method for producing a low-resistance metal ruthenium-containing thin film by chemical vapor deposition using an oxygen source without ruthenium oxide contamination.

General formula (1)

(In the formula, X and Y are linear or branched alkyl groups (however, the total number of carbon atoms contained in X and Y is 2 to 10), and Z is a hydrogen atom or carbon. An alkyl group having 1 to 4 atoms, L represents an unsaturated hydrocarbon compound having at least two double bonds;
Chemical vapor deposition characterized by using an organic ruthenium complex having a β-diketonato and an unsaturated hydrocarbon compound having at least two double bonds as a ligand, or a ruthenium source and an oxygen source thereof as a solvent solution. This is solved by a method for producing a metal-containing ruthenium-containing thin film.

  The present invention can provide a method for producing a low-resistance metal ruthenium-containing thin film by chemical vapor deposition using an oxygen source without containing ruthenium oxide.

  The organoruthenium complex having the β-diketonato of the present invention and an unsaturated hydrocarbon compound having at least two double bonds as a ligand is represented by the general formula (1). In the general formula (1), X and Y are linear or branched alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, t A straight or branched alkyl group having 1 to 6 carbon atoms such as butyl group, pentyl group, isopentyl group, neopentyl group, n-hexyl group, isohexyl group, etc., but carbon atoms contained in X and Y The total number is 2-10. L represents an unsaturated hydrocarbon compound having at least two double bonds, such as 1,5-hexadiene, 1,5-cyclooctadiene, norbornadiene, 1,4-cyclohexadiene, 2,5- Dimethyl-2,4-hexadiene, 4-vinyl-1-cyclohexene and 1,3-pentadiene are preferably used.

  The β-diketone which is the base of β-diketonato which is a ligand of the organoruthenium complex of the present invention is a compound that can be easily synthesized by a known method.

  Specific examples of the organoruthenium complex having β-diketonato and an unsaturated hydrocarbon compound having at least two double bonds as ligands are represented by, for example, formulas (2) to (20).

  In the CVD method, it is necessary to vaporize the organic ruthenium complex in order to form a thin film. As a method for vaporizing the organic ruthenium complex of the present invention, for example, the organic ruthenium complex itself is filled or transported into the vaporization chamber. As well as organic ruthenium complexes in an appropriate solvent (for example, aliphatic hydrocarbons such as hexane, methylcyclohexane, ethylcyclohexane, and octane; aromatic hydrocarbons such as toluene; tetrahydrofuran, dibutyl ether, etc. A method (solution method) may be used in which the solution diluted in (1) is introduced into the vaporizing chamber with a liquid transfer pump and vaporized.

  In the present invention, when a metal ruthenium film is deposited on a substrate using the organoruthenium complex and an oxygen source, the pressure in the reaction system is preferably 1 Pa to 200 kPa, more preferably 10 Pa to 110 kPa. The temperature of the product is preferably 100 to 600 ° C, more preferably 150 to 450 ° C. Further, when depositing a metal thin film with an oxygen source, oxygen gas is preferably used as the oxygen source, and oxygen gas diluted with an inert gas is preferably used, and the content ratio of oxygen gas to the total gas amount is preferably 0.1 to 10% by volume.

  Next, the present invention will be specifically described with reference to examples, but the scope of the present invention is not limited thereto.

Synthesis of Reference Example 1 (bis (acetylacetonato) (1,5-hexadiene) ruthenium (II) (hereinafter referred to as [Ru (acac) ₂ (hd)]) A stirrer, a thermometer and a dropping funnel were provided. To a 100 ml flask, add 8.87 g (33.9 mmol) of ruthenium trichloride trihydrate, 6.12 g (74.5 mmol) of 1,5-hexadiene and 60 ml of isopropyl alcohol, and react at 70 ° C. for 4 hours with stirring. After that, an aqueous solution obtained by mixing 10.6 g (106 mmol) of acetylacetone and 4.22 g (106 mmol) of sodium hydroxide was added dropwise and reacted for 0.5 hours with stirring. After filtration, the filtrate was concentrated and the concentrate was distilled under reduced pressure (140 ° C., 39 Pa) to obtain a tan viscous liquid. Purify the liquid by silica gel column chromatography (developing solvent) Hexane / ethyl acetate = 9/1 (volume ratio)) to obtain 10.3 g of bis (acetylacetonato) (1,5-hexadiene) ruthenium (II) as a tan viscous liquid (isolation yield: 80 %).
The physical properties of bis (acetylacetonato) (1,5-hexadiene) ruthenium (II) were as follows.

IR (neat (cm ^-1 )); 3076, 2923, 1576, 1517, 1400, 1268, 1201, 1022, 933, 767, 620, 432
(The peak specific to β-diketone (1622 cm ^-1 ) disappeared, and the peak specific to β-diketonato (1576 cm ^-1 ) was observed.)
Elemental analysis (C ₁₆ H ₂₄ O ₄ Ru); carbon: 50.2%, hydrogen: 6.45%, ruthenium: 26.3%
(Theoretical value: Carbon: 50.4%, Hydrogen: 6.34%, Ruthenium: 26.5%)
MS (m / e); 382, 300, 43

Examples 1 to 5 and Comparative Examples 1 to 3 (deposition experiment; evaluation of resistance value of metal ruthenium thin film with varying oxygen concentration)
Using the organic ruthenium complex ([Ru (acac) ₂ (hd)]) obtained in Reference Example 1, a vapor deposition experiment by a CVD method was performed to evaluate the relationship between the oxygen concentration and the resistance value of the metal ruthenium film.
The apparatus shown in FIG. 1 was used for the evaluation test. The ruthenium complex 7 in the vaporizer 5 (glass ampoule) is heated by the heater 6 to vaporize and exits the vaporizer 6 along with the helium gas introduced through the mass flow controller 1A. The gas exiting the vaporizer 6 is introduced into the reactor 11 together with the oxygen gas introduced through the mass flow controller 1B and the stop valve 2. The oxygen gas concentration is adjusted by helium gas introduced through the mass flow controller 1C and the stop valve 3. The pressure in the reaction system is controlled to a predetermined pressure by opening and closing the valve 14 in front of the vacuum pump, and is monitored by the pressure gauge 12. The central part of the glass reactor has a structure that can be heated by the heater 10. The ruthenium complex introduced into the reactor is set in the center of the reactor and decomposes on the surface of the deposition substrate 9 heated to a predetermined temperature by the heater 10, and a metal ruthenium thin film is deposited on the substrate 9. To do. The gas exiting the reactor 11 is exhausted to the atmosphere via a trap 13 and a vacuum pump.

The common deposition conditions in all experiments are as follows.
Organic ruthenium complex vaporization temperature: 80 ℃
Helium carrier gas flow rate: 40ml / min.
Substrate material: SiO ₂ / Si
Substrate temperature: 360 ° C
Reaction system pressure: 1729Pa
Deposition time: 10 minutes Total gas flow rate: 200 ml / min.

  The vapor deposition results (film characteristics) are shown in Table 1. Note that a 6 mm × 20 mm rectangular substrate was used as the deposition base.

From the above results, the organoruthenium complex ([Ru (acac) ₂ (hd)]) is an excellent metal ruthenium in which the oxygen source, in particular, the proportion of oxygen gas is 0.1 to 10% by volume with respect to the total gas amount. It can be seen that the film can be formed.

  The present invention can provide a method for producing a low-resistance metal ruthenium-containing thin film by chemical vapor deposition using an oxygen source without containing ruthenium oxide.

It is a figure which shows the structure of a vapor deposition apparatus.

Explanation of symbols

3 Vaporizer 4 Reactor 10B Vaporizer heater 10C Reactor heater 20 Raw material organic ruthenium complex melt 21 Substrate

Claims (5)

General formula (1)

(In the formula, X and Y are linear or branched alkyl groups (however, the total number of carbon atoms contained in X and Y is 2 to 10), and Z is a hydrogen atom or carbon. An alkyl group having 1 to 4 atoms, L represents an unsaturated hydrocarbon compound having at least two double bonds;
Chemical vapor deposition characterized by using an organic ruthenium complex having a β-diketonato and an unsaturated hydrocarbon compound having at least two double bonds as a ligand, or a ruthenium source and an oxygen source thereof as a solvent solution. A method for producing metal ruthenium-containing thin films.   The chemistry according to claim 1, wherein the unsaturated hydrocarbon compound having at least two double bonds is 1,5-hexadiene, 1,5-cyclooctadiene, norbornadiene, 4-vinyl-1-cyclohexene or 1.3-pentadiene. A method for producing a thin film containing metal ruthenium by vapor deposition.   A method for producing a metal ruthenium-containing thin film by chemical vapor deposition using an oxygen gas as an oxygen source.   The method for producing a metal ruthenium-containing thin film by chemical vapor deposition according to claim 1, wherein the proportion of oxygen gas is 0.1 to 10% by volume based on the total gas amount.   A method for producing a metal ruthenium-containing thin film by chemical vapor deposition, wherein the solvent to be used is at least one solvent selected from the group consisting of aliphatic hydrocarbons, aromatic hydrocarbons and ethers.

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