KR100958332B1 - A new ruthenium compound and vapor deposition method using the same - Google Patents

Abstract

The present invention relates to a ruthenium compound of Formula 1 and a ruthenium thin film deposition method using the same.

<Formula 1>

The ruthenium compound according to the present invention has a suitable volatility, deposition temperature, thermal stability and deposition performance for thin film deposition, and the ruthenium thin film deposited by using the RuO _x formation, impurities, and step coverage problems of the conventional ruthenium precursor compound By solving the problem, there is a great advantage in the application of highly integrated semiconductor device manufacturing and related industries.

Ruthenium, deposition, compound, ligand, precursor, thin film, atomic layer, vapor

Description

A ruthenium compound and vapor deposition method using the same

The present invention relates to a method for preparing a precursor compound for ruthenium thin film deposition in which a benzene having an alkyl derivative and a 1,3-cyclohexadiene (cyclohexa-1,3-diene) having an alkyl derivative are coordinated. It relates to a ruthenium precursor having a novel ligand and a method for producing a ruthenium thin film using the same.

In order to effectively implement a highly integrated memory device, a metal material having stable electrode characteristics is required. In particular, as the aspect ratio increases as the integration of devices increases, an electrode material having excellent step coverage needs to be developed, and an electrode capable of preventing plug oxidation while having good oxidation resistance characteristics is required. As such, the most widely used ones are ruthenium (Ru) and iridium (Ir).

In particular, the ruthenium thin film is used as an electrode material of a DRAM capacitor, which is a highly integrated memory device, or as a diffusion barrier of a copper wiring material in a semiconductor device. Ruthenium thin films are generally good conductors that do not react to silicon and metal oxides and are resistant to oxygen and silicon diffusion.

Therefore, there is a continuous need for a method of providing a ruthenium film by using a chemical vapor deposition technique or an atomic layer deposition method with many ruthenium compounds that can be used as precursors for producing the film.

In many ruthenium precursor compounds that can be applied to chemical vapor deposition or atomic layer deposition, especially ruthenium (0) compounds are precursor compounds having zero oxidation number of the central metal, under various temperature conditions using chemical vapor deposition or atomic layer deposition ( 150 ~ 450 ℃) Easy to manufacture Ru thin film having high oxidation resistance and electrical conductivity. In addition, residual materials and ligands remain as neutral materials after thermal decomposition, so they are not included in the film and can be easily removed by vacuum exhaust.

Conventionally, sputtering or chemical vapor deposition (CVD) has been used to prepare a ruthenium thin film. Sputtering is a method of colliding accelerated particles with a solid surface to attach atoms protruding into space by exchanging momentum to a substrate. Therefore, the above method is difficult to apply to a capacitor of a highly integrated semiconductor device having a complicated three-dimensional structure because it is to investigate the properties of the thin film. In addition, the chemical vapor deposition method is a method of vaporizing the compound to be thin film to the reaction chamber to obtain a thin film of the desired material using a chemical reaction. This method has been used until recently because of its excellent step coverage and aspect ratio characteristics, but it has also become difficult to obtain desired characteristics as the semiconductor memory device is highly integrated to 256 MB or more.

As a result, a ruthenium thin film using atomic layer deposition (ALD) has received new attention. The atomic layer deposition method is a method of depositing an atomic layer on a semiconductor substrate by sequentially repeating a process of injecting a reactant into a chamber and removing residual reactants and by-products. The atomic layer deposition method is a deposition method using a chemical reaction like the CVD method, but the CVD method is injected in the chamber by injecting each gas at the same time, while the ALD method is injected in the form of pulses by one type of gas, Are distinguished.

Specifically, a method of manufacturing a ruthenium thin film using an atomic layer deposition method is conventionally known as ruthenium raw material Ru (OD) ₃ [tris (2,4-octanedionato) Ruthenium (III)], Ru (EtCP) ₂ [bis (ethylcyclopentadienyl) Ruthenium (Ⅱ)]. However, among them, Ru (OD) ₃ contains oxygen, making it difficult to deposit pure ruthenium on the reaction substrate, and further, RuO _x is formed on a portion of the substrate. In addition, in the case of Ru (EtCP) ₂ , due to the characteristics of the cyclo-pentadiene series, it is difficult for ruthenium atoms to break chemical bonds and exist independently, resulting in a large amount of impurities remaining in the ruthenium thin film. RuO ₂ by deposition using an O ₂ plasma Since a film is formed, there is a problem in that a process of reducing using H ₂ again is required in order to obtain a Ru film.

When the ruthenium thin film is formed as a precursor, RuO _x formation or impurities are minimized, zero valence is given, and a uniform vapor pressure in the form of liquid is provided. The aim is to provide new ruthenium compounds that are absent.

Another object of the present invention is to provide a method for forming a ruthenium thin film having excellent physical properties using a novel ruthenium compound.

The present invention relates to a new ruthenium compound and a method for producing a ruthenium thin film using the same, which can solve the disadvantages of existing precursors for the deposition of the ruthenium thin film.

The present invention provides a ruthenium compound of the formula (1).

<Formula 1>

In addition, the present invention provides a ruthenium thin film manufacturing method comprising the following steps.

a) depositing an atomic layer on the substrate by injecting the ruthenium compound of Formula 1 into a gas phase into a reactor equipped with a substrate; And

b) purging the residual ruthenium compound and reaction byproducts.

The method for manufacturing a ruthenium thin film according to the present invention is a method for forming a thin film with a desired thickness by repeating the above manufacturing step in one cycle by atomic layer deposition.

In addition, the method of manufacturing a ruthenium thin film according to the present invention may further include the step of injecting a reaction gas selected from hydrogen or ammonia after the step b), and purging the residual reaction gas and the reaction by-products, the reaction The gas may be ammonia or hydrogen or an ammonia plasma or hydrogen plasma excited through a remote plasma generator. Injecting the ammonia plasma formed through a remote plasma generator improves the reactivity with the ruthenium precursor compared to the ammonia gas, and can be produced a ruthenium thin film with less contamination is more preferable.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention in more detail. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the embodiments are intended to complete the disclosure of the present invention, and to those skilled in the art to fully understand the scope of the invention. It is provided to inform you. Like numbers refer to like elements in the figures.

A schematic diagram of an atomic layer deposition apparatus according to the present invention is disclosed in FIG. 1. Referring to FIG. 1, an atomic layer deposition apparatus includes an atomic layer deposition reactor 10, a substrate 20 mounted thereon, a heater 20 for heating a substrate, a bubbler 40 that is a container containing a ruthenium compound, and the bubble. And a gas injection tube 45 and a vacuum pump 50 for injecting the ruthenium compound and the transport gas vaporized from the furnace into the reactor. The atomic layer deposition apparatus according to the present invention may further include a gas injection tube for injecting a reaction gas such as hydrogen or ammonia, and may further include a remote plasma generator.

Referring to FIGS. 1 and 2, a method of depositing an atomic layer according to the present invention includes mounting a substrate 30 in an atomic layer deposition reactor 10 (S10), heating the bubbler 40, and transporting gas. Injecting the ruthenium precursor and the transport gas stored in the bubbler into the reactor through the gas injection pipe 45 (S20), the ruthenium precursor injected into the reactor is adsorbed on the substrate to deposit an atomic layer (S30) And purging the remaining ruthenium precursor and the reaction by-product (S40), and repeating the preparation step with one cycle to adjust the target thickness to the target thickness (S50).

In addition, the method of manufacturing a ruthenium thin film according to the present invention may further include the step of reacting with a reaction gas selected from hydrogen or ammonia in the manufacturing step corresponding to the one cycle, and purging the residual reaction gas and the reaction by-products This is illustrated in FIG. 3. Referring to FIG. 3, a step of injecting a ruthenium precursor and adsorbing onto a substrate (S100), a step of purging a residual ruthenium compound (S200), a step of injecting a reaction gas selected from hydrogen or ammonia and reacting (S300), and The manufacturing step consisting of purging the residual reaction gas (S400) is repeated one cycle to form a thin film of the desired thickness.

The ammonia or hydrogen gas is a gas having a reducing power, which helps to decompose the ruthenium precursor on the reaction substrate to increase the deposition rate of the ruthenium thin film and to discharge impurities in the form of hydride, which is useful for manufacturing a high purity thin film, and through a remote plasma generator. Injecting the formed ammonia plasma or hydrogen plasma is more advantageous for the thin film deposition rate and high purity thin film production.

As described above, the present invention has suitable volatility, deposition temperature, thermal stability, and deposition performance as a precursor compound for preparing a ruthenium thin film, and a ruthenium thin film deposited by using a metal precursor compound is RuO possessed by a conventional ruthenium precursor compound. By solving the _x formation, impurities, and step coverage problems, it can be said that it is widely used in the manufacture of highly integrated semiconductor devices and related industries.

Hereinafter, the precursor compound and the thin film manufacturing method of the present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited by the following examples.

Example 1 Synthesis of Ru (η ⁶ -p -Cymene) (η ⁴ -1,3-cyclohexadiene)

In a round flask (1000 ml) with a branched flask in nitrogen atmosphere, purified di-μ-chloro-bis [chloro (η ⁶ -p-cymene) ruthenium (II)] ([RuCl ₂ ( p -cymene) )] ₂ (ref. Inorganic synthesis, vol 21, 75p) 28 g (0.047 mole) and 30 g (0.28 mole) of sodium carbonate (Na2CO3) were added thereto, followed by 1,3-cyclohexadiene. ) (9.4 g, 0.1175 mol) was added using a syringe and refluxed at room temperature for 5 hours to complete the reaction, cooled to room temperature and vacuum removed to remove ethanol and volatile byproducts. Primary purification was carried out at 110 ° C. under vacuum (0.6 mmHg), and secondary purification was carried out at 120 ° C. under vacuum (1.0 mmHg) to give 9 g (60%) of the title compound as a yellow liquid. .

¹ H-NMR (C ₆ D ₆ , ppm) δ 1.04 (d, 6H), 1.75 (dd, 4H), 1.90 (s, 3H), 1.84 (s, 3H), 2.25 (m, 1H), 2.98 ( m, 2H), 4.78 (m, 2H), 4.96 (m, 4H); ¹³ C-NMR (C ₆ D ₆ , ppm) 20.4, 24.1, 28.8, 32.7, 54.0, 75.7, 79.2, 80.7, 93.38, 104.7.

<Example 2> Preparation of ruthenium thin film

A ruthenium thin film was prepared using the ruthenium compound Ru (η ⁶ -p -Cymene) (η ⁴ -1,3-cyclohexadiene) prepared in Example 1.

Referring to FIGS. 1 and 3, the manufacturing process of the silicon wafer 30 in the chamber 10 is about 400 ° C., and Ru (η ⁶ − p ) in the stainless steel bubbler container 40 is described. The temperature of the -Cymene) (η ⁴ -1,3-cyclohexadiene) precursor is 60 ° C. Subsequently, first, Ru (η ⁶ -p -Cymene) (η ⁴ -1,3-cyclohexadiene) precursor is injected into the reaction chamber using argon gas as a transport gas (S100). This results in the formation of an atomic layer as previously mentioned. Second, purging with the vacuum pump 50 for about 5 seconds (S110), residual gas or Ru (η ⁶ - p -Cymene) (η ⁴ -1,3-cyclohexadiene) present in the chamber (10) Remove the precursor. Third, the ammonia plasma excited by the remote plasma former outside the chamber is injected into the chamber for about 5 seconds (S120) to react with the precursor adsorbed on the silicon wafer 30 to form a ruthenium thin film. Fourth, the residue decomposed by the reaction for about 5 seconds to purge again by using the vacuum pump 50 (S130) to remove. 40 cycles of ruthenium thin films were prepared by repeating 40 cycles using the above-described process step as one cycle.

1 is a schematic view of an atomic layer deposition reaction apparatus according to the present invention,

2 is a flowchart of an atomic layer deposition process according to the present invention,

3 is another atomic layer deposition process flow chart in accordance with the present invention.

<Explanation of symbols for the main parts of the drawings>

10 reactor 20 heater 30 substrate

40: bubbler 45: gas injection pipe 50: pump

Claims (4)

delete a) atomic layer deposition on a substrate by injecting a ruthenium compound of Formula 1 into a gas phase into a reactor equipped with a substrate; And b) purging the residual ruthenium compound and reaction byproducts; Method for producing a ruthenium thin film, characterized in that for repeating the manufacturing step comprising a. <Formula 1>

The method of claim 2, Injecting a reaction gas selected from hydrogen or ammonia after step b), and purging the residual reaction gas and the reaction by-product. The method of claim 3, wherein The reaction gas is a method of manufacturing a ruthenium thin film, characterized in that the injection in the plasma state.

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