KR102536802B1 - Method for selectively depositing Ruthenium thin film - Google Patents

Abstract

The present invention relates to a method for selectively depositing a ruthenium thin film, and more particularly, to a method for depositing a ruthenium thin film on a conductive layer using a ruthenium precursor having a specific ligand.

Description

Method for selectively depositing Ruthenium thin film}

The present invention relates to a method for selectively depositing a ruthenium thin film, and more particularly, to a method for depositing a ruthenium thin film on a conductive layer using a ruthenium precursor having a specific ligand.

With the emergence of autonomous vehicles, virtual reality, and mobile devices such as 5G, the semiconductor industry requires continuous miniaturization of devices for high performance, and for this, new high-performance materials as well as developments in engineering are required.

Ruthenium is considered the most suitable material for semiconductor integration due to its high melting point, excellent density, and ability to conduct current. Ruthenium-based thin films exhibit excellent conductivity and are considered to be applicable not only to semiconductors but also to microelectronic devices. These ruthenium thin films are typically deposited by chemical vapor deposition (CVD) and atomic layer deposition (ALD) methods.

On the other hand, with the advancement of semiconductor device design, a deposition method in an atomic layer unit is required for device manufacturing in deposition of each circuit. Selective deposition technology is a technology capable of depositing atomic layer units by chemical selection in semiconductor film patterning. In addition, since processes such as lithography necessary for pattern formation are omitted by the selective deposition technique, there is a great advantage in device manufacturing.

Therefore, there is a demand for technical development of a method for selectively depositing ruthenium that can be applied to device manufacturing.

KR10-2020-0087878 (published on July 21, 2020)

The present invention provides a method for depositing a ruthenium thin film having excellent selectivity of the ruthenium thin film with respect to a conductive layer of a substrate in which a conductive layer containing a metal and an insulating layer are present.

The problem to be solved by the present invention is not limited to the above-mentioned problem, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

For the above purpose, a method for selectively depositing a ruthenium thin film according to embodiments of the present invention is provided.

A method for selectively depositing a ruthenium thin film according to embodiments of the present invention includes the steps of a) providing a substrate including a conductive layer material and an insulating layer material and stabilizing the substrate; b) removing impurities from the surface of the substrate using a cleaning material; and c) supplying a ruthenium-containing precursor and a reaction gas to the substrate from which the impurities are removed.

In embodiments of the present invention, the conductive layer material includes a metal, a metal nitride, a metal oxide, or a combination thereof.

In embodiments of the present invention, the insulating layer material may be a high dielectric (high- k , k >5) or low dielectric (low- k , k <5) material.

In embodiments of the present invention, the steps may be performed at a temperature ranging from 200 °C to 500 °C.

In embodiments of the present invention, the steps may be performed at 10 torr or less.

In embodiments of the present invention, the reaction gas is composed of H ₂ , Ar, H ₂ O, NH ₃ , N ₂ gas, H ₂ plasma, Ar plasma, NH ₃ plasma, N ₂ plasma, and mixtures thereof. It may be any one or more selected from the group, and in this case, a nitrogen-containing reaction gas is essentially included.

In embodiments of the present invention, the ruthenium precursor may be a precursor having a (TMEDA) ligand.

In embodiments of the present invention, the cleaning material is selected from the group consisting of H ₂ , Ar, He, N ₂ , NH ₃ , H ₂ plasma, Ar plasma, N ₂ plasma, NH ₃ plasma, and mixtures thereof. can be one or more of the

In embodiments of the present invention, the method of selectively depositing the ruthenium thin film may be performed by chemical vapor deposition or atomic layer chemical vapor deposition.

In addition, a ruthenium thin film according to embodiments of the present invention is provided. The ruthenium thin film is formed using a selective deposition method of the ruthenium thin film.

Wiring of a semiconductor device according to embodiments of the present invention is provided. The wiring of the semiconductor device may include the ruthenium thin film; and a conductive wiring layer on the ruthenium thin film.

In embodiments of the present invention, the ruthenium thin film may be a seed layer for forming the wiring layer by an electrolytic plating method.

A capacitor according to embodiments of the present invention is provided. The capacitor may include the ruthenium thin film; and a dielectric layer on the ruthenium thin film.

According to the present invention, a ruthenium thin film can be deposited with excellent selectivity with respect to the conductive layer of a substrate having a metal-containing conductive layer and an insulating layer without a separate lithography process using a ruthenium precursor having a (TMEDA) ligand. there is

1 is a schematic process flow diagram of a method for selectively depositing a ruthenium thin film according to the present invention.
2 is a TEM photograph showing a selective deposition experiment of a ruthenium thin film according to Example 1-1 of the present invention.
3 is a TEM photograph showing a selective deposition experiment of a ruthenium thin film according to Examples 1-2 of the present invention.
4 is a TEM photograph showing a selective deposition experiment of a ruthenium thin film according to Comparative Example 1 of the present invention.

Hereinafter, with reference to preferred embodiments and drawings of the present invention will be described so that those skilled in the art can easily carry out. In addition, in the description of the present invention, if it is determined that a detailed description of a related known function or known configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

Since the present invention can apply various transformations and have various embodiments, specific embodiments will be exemplified and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all conversions, equivalents, or substitutes included in the spirit and scope of the present invention. Also, throughout the specification, when a part "includes" a certain component, it means that it may further include other components, not excluding other components, unless otherwise stated.

Terms used in the present invention are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In the present invention, terms such as include or have are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features, numbers, or steps However, it should be understood that it does not preclude the possibility of existence or addition of operations, components, parts, or combinations thereof.

1 is a schematic process flow diagram for explaining a method for selectively depositing a ruthenium thin film according to the present invention.

Referring to FIG. 1 , a method for selectively depositing a ruthenium thin film according to the present invention includes the steps of a) providing a substrate including a conductive layer material and an insulating layer material and stabilizing the substrate; b) removing impurities from the surface of the substrate using a cleaning material; and c) supplying a ruthenium-containing precursor and a reaction gas to the substrate from which the impurities are removed.

In one embodiment, the steps of a) providing a substrate including a conductive layer material and an insulating layer material and stabilizing the substrate may include providing the substrate and supplying an inert gas to the provided substrate while the substrate is at a deposition temperature of 200 ° C. This is a step to sufficiently reach to 500 ° C.

If the deposition temperature is less than 200 ° C, the precursor does not decompose due to low reaction energy, so there is a problem of not being deposited. Occurs.

In one embodiment, the deposition temperature is preferably 300 °C to 400 °C.

In one embodiment, the supplied inert gas may be at least one selected from the group consisting of H ₂ , Ar, NH ₃ , N ₂ gas, H ₂ plasma, Ar plasma, NH ₃ plasma, N ₂ plasma, and mixtures thereof. The amount supplied may be determined according to the size of the device. For example, if the size of the substrate is 2cm x 2cm, 500 sccm is supplied.

In some embodiments, the conductive layer material includes a metal, a metal, a metal nitride, a metal oxide, or a combination thereof. Specifically, it includes or essentially includes one or more of Pt, Cu, Co, W, Ta, Ti, or oxides, nitrides or oxynitrides thereof.

In some embodiments, the insulating layer material may be a low dielectric material (low- k , k <5) and may include silicon. Specifically, the insulating material includes or essentially includes one or more of SiO ₂ , SiN, or high-resistance Si.

In one embodiment of the present invention, the conductive material essentially includes W, Pt, or TiN, and the insulating material essentially includes SiO ₂ or SiN.

In one embodiment, the step b) removing impurities from the surface of the substrate using a cleaning material is a step of removing impurities on the substrate by pretreatment of the substrate using a cleaning material and plasma.

In one embodiment, the cleaning material is any one selected from the group consisting of H ₂ , Ar, He, N ₂ , NH ₃ , H ₂ plasma, Ar plasma, N ₂ plasma, NH ₃ plasma, and mixtures thereof. It may be more than 1, and the power applied to the plasma is 10 to 100 W. At this time, the process pressure is performed at 10 Torr or less, preferably 1 to 5 Torr.

In one embodiment, in the step of c) supplying the ruthenium-containing precursor and the reaction gas to the substrate from which impurities are removed, a ruthenium thin film is formed on the substrate by the supplied ruthenium-containing precursor and reaction gas.

In one embodiment, the ruthenium-containing precursor is a ruthenium-containing precursor having a (TMEDA) ligand, Ru(TMEDA)(acac) ₂ , Ru(TMEDA) ₃ , Ru(TMEDA) ₂ (COD), Ru(TMEDA) ₂ (CO) ₂ , Ru(TMEDA)Cl _{2 ,} Ru(TMEDA)(hfac) _{2 ,} or Ru(TMEDA) ₂ (hfac).

The ruthenium-containing precursor is delivered to the substrate in the chamber as a ruthenium-containing gas, and the ruthenium-containing gas may be provided in one or more pulses or continuously. The flow rate of the ruthenium-containing gas is any, including flow rates in the range of about 10 to about 2000 sccm, or in the range of about 20 to about 1000 sccm, or in the range of about 30 to about 500 sccm, or in the range of about 50 to about 200 sccm. It may be a suitable flow rate of

In one embodiment, the reactive gas is selected from the group consisting of H ₂ , Ar, H ₂ O, NH ₃ , N ₂ gas, H ₂ plasma, Ar plasma, NH ₃ plasma, N ₂ plasma, and mixtures thereof It may be any one or more, and in this case, a reaction gas of a material containing a nitrogen atom is essentially included.

In one embodiment, the reactive gas may be supplied simultaneously or sequentially with the ruthenium precursor, and in the case of simultaneous introduction as described above, each may be individually introduced or mixed before introduction.

In some embodiments, the reactive gas is supplied to the substrate in the chamber at a constant flow ranging from about 1 sccm to about 5,000 sccm.

In some embodiments, the reactive gas is supplied to the substrate in the chamber at a rate ranging from 2.5 to 500 times the flow rate of the ruthenium-containing precursor gas.

In some embodiments, the substrate temperature during deposition can be controlled, for example by setting the temperature of the substrate support or susceptor.

In some embodiments, the substrate temperature during deposition is maintained at a temperature in the range of 200 °C to about 500 °C, or in the range of about 250 °C to about 450 °C, or in the range of about 300 °C to about 400 °C. If the substrate temperature is less than 200 ℃, there is a problem that the ruthenium precursor itself does not decompose due to low reaction energy and is not deposited. can happen

Although described with reference to the technical spirit and specific embodiments of the present invention as described above, it will be understood that these embodiments merely illustrate the technical spirit and principles of the present invention. It will be apparent to those skilled in the art that various modifications and changes can be made to the method according to the technical spirit of the present invention without departing from the spirit and scope of the present invention.

In the following, the present invention will be described using specific examples.

Example 1

In order to manufacture a ruthenium thin film, a wafer piece having a size of 2 cm X 2 cm including a layer of W and SiO ₂ was placed in a deposition equipment and subjected to thermal CVD deposition.

The substrate temperature is stabilized for 5 minutes while supplying 500 sccm of Ar so that the substrate can sufficiently reach the deposition temperature of 200 °C or 500 °C.

In order to remove impurities on the substrate, surface pretreatment (cleaning) using H ₂ and Ar plasma was performed for 5 minutes. At this time, 500 sccm of H ₂ and 500 sccm of Ar were simultaneously supplied, the process pressure was 3.1 torr, and the power applied to the plasma was set to 50 W.

Ru(TMEDA)(acac) ₂ 200 sccm (Example 1-1) and Ru(TMEDA)(hfac) ₂ 200 sccm (Example 1-2) were used as the ruthenium-containing precursor.

As the reactive gas, 250 sccm and 250 sccm of ammonia and hydrogen were mixed and used at the same time, respectively, and ruthenium thin films were obtained by the ruthenium-containing precursors of Examples 1-1 and 1-2.

Comparative Example 1

As a ruthenium-containing precursor A ruthenium thin film was obtained in the same manner as in Example 1, except that Ru(CO) ₂ (hfac) ₂ was used.

Table 1 below describes specific film formation conditions and results of Example 1-1, Example 1-2, and Comparative Example 1.

precursor Ru(TMEDA)(acac) ₂ Ru(TMEDA)(hfac) ₂ Ru(CO) ₂ (hfac) ₂ Board W, SiO ₂ W, SiO ₂ W, SiO ₂ Substrate temperature (℃) 330 400 400 reactive gas NH ₃ /H ₂ NH ₃ /H ₂ NH ₃ /H ₂ thin film deposition time 10min 50min 10min Reactive Gas Injection Amount NH ₃ 250 sccm
_H2 250 sccm NH ₃ 250 sccm
_H2 250 sccm NH ₃ 250 sccm
_H2 250 sccm chamber pressure 6 torr 5 torr 5 torr selectivity 4.6:1 1.1:1 0.93:1 Evaporation thickness (on W) 15.7 nm 95 nm 25 nm Deposition thickness (on SiO ₂ ) 3.4 nm 87 nm 27 nm

As shown in Table 1, Ru(TMEDA)(acac) ₂ , a ruthenium-containing precursor having a (TMEDA) ligand, and Ru(TMEDA)(hfac) _{2 ,} a ruthenium-containing precursor having no (TMEDA) ligand, Ru(CO ) ₂ (hfac) ₂ , the selectivity for the tungsten (W) layer, which is a conductive layer, was 4.6 times and 1.1 times, respectively.

2 shows a TEM of a film formed on a conductive layer (W) and an insulating layer (SiO ₂ ) when Ru(TMEDA)(acac) ₂ is used as a ruthenium-containing precursor having a (TMEDA) ligand (Example 1-1). are showing The thicknesses of the films formed on the conductive layer (W) and the insulating layer (SiO ₂ ) were 15.7 nm and 3.4 nm, respectively, indicating that the deposition selectivity ratio of the ruthenium film to the conductive layer was 4.6:1.

3 shows a TEM of a film formed on a conductive layer (W) and an insulating layer (SiO ₂ ) when Ru(TMEDA)(hfac) ₂ is used as a ruthenium-containing precursor having a (TMEDA) ligand (Example 1-2). are showing The thicknesses of the films formed on the conductive layer (W) and the insulating layer (SiO ₂ ) were 95.0 nm and 87.0 nm, respectively, indicating that the deposition selectivity of the ruthenium film relative to the conductive layer was 1.1:1.

4 shows a TEM of a film formed on a conductive layer (W) and an insulating layer (SiO ₂ ) when Ru(CO) ₂ (hfac) ₂ is used as a ruthenium-containing precursor having no (TMEDA) ligand (Comparative Example 1). are showing The thicknesses of the films formed on the conductive layer (W) and the insulating layer (SiO ₂ ) were 25.0 nm and 27.0 nm, respectively, indicating that the deposition selectivity of the ruthenium film relative to the conductive layer was 0.93:1.

As such, when the method for selectively depositing a ruthenium thin film of the present invention using a ruthenium-containing precursor having a (TMEDA) ligand is used, it can be seen that the selectivity for the conductive layer is excellent when forming the ruthenium thin film.

The scope of the present invention is not limited to the above-described embodiments, but may be implemented in various forms of embodiments within the scope of the appended claims. Anyone with ordinary knowledge in the art to which the invention pertains without departing from the subject matter of the invention claimed in the claims is considered to be within the scope of the claims of the present invention to various extents that can be modified.

Claims (10)

a) Provision of a substrate containing a conductive layer material and an insulating layer material and the inside of the substrate
purification step;
b) removing impurities from the surface of the substrate using a cleaning material;
c) Supplying a ruthenium-containing precursor and a reaction gas to the substrate from which the impurities are removed
Including;
The cleaning material includes an inert gas,
The reaction gas essentially contains a substance containing NH3 and does not contain O2;
The ruthenium precursor compound is Ru(TMEDA)(hfac)2 or Ru(TMEDA)(acac)2, characterized in that, a selective deposition method for a ruthenium metal thin film The method of claim 1,
The conductive layer material comprises Pt, Cu, Co, W, Ta, Ti, or one or more of oxides, nitrides or oxynitrides thereof. Method for selectively depositing a ruthenium metal thin film The method of claim 1,
Characterized in that the insulating layer material includes at least one of SiO ₂ , SiN, or high-resistance Si, a selective deposition method for a ruthenium metal thin film The method according to claim 1, wherein the conductive layer material is W (tungsten), Pt, or TiN. The selective deposition method of a ruthenium metal thin film according to claim 1, characterized in that the insulating layer material is SiO2 or SiN. delete The method for selectively depositing a ruthenium metal thin film according to claim 1, wherein the reaction gas includes H ₂ in addition to a compound containing nitrogen atoms. The method of claim 1,
The step of stabilizing the substrate is a step of allowing the substrate to reach a deposition temperature of 200 ° C to 500 ° C while supplying an inert gas to the provided substrate, characterized in that, a method for selectively depositing a ruthenium metal thin film The method of claim 1,
Selective deposition method of a ruthenium metal thin film, characterized in that the selective deposition method of the ruthenium metal thin film proceeds by thermal CVD

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