Method for forming ruthenium-containing layer and laminate

Abstract

To provide a ruthenium-containing layer formation method and a laminate that selectively form a ruthenium-containing layer on the surface of a pattern-forming mask formed on a substrate as a protective layer that does not require the formation of a selectivity-inducing element and can suppress the generation of etching residue.SOLUTION: A method for forming a ruthenium-containing layer includes a preparation step of preparing a substrate having an oxidized layer, and a deposition step of depositing a ruthenium-containing layer on the oxidized layer using ruthenium oxide by a vapor phase growth method, and the oxidized layer contains carbon atoms.SELECTED DRAWING: Figure 1C

Description

Technical Field

[0001] The present disclosure relates to a method for forming a ruthenium-containing layer and a laminate.

Background Art

[0002] Photosensitive polymer photoresist is used in photolithography to process the patterned portion of a thin film or the bulk of a semiconductor substrate. After the photoresist is exposed and developed, a three-dimensional structure is finally formed on the substrate by a high-directivity anisotropic reactive ion etching (hereinafter sometimes referred to as "RIE") process. In nanoelectronics, since miniaturization and complication of three-dimensional shapes are increasingly required, the photoresist alone may be too thin for pattern transfer. For example, a photoresist for lithography of 22 nm or less may not withstand high-energy ion irradiation and may rapidly deteriorate during RIE. To overcome this problem, materials such as amorphous carbon (hereinafter sometimes referred to as "AC") with higher selectivity and resistance than photoresist are introduced to form a mask laminate of amorphous carbon and photoresist. Ideally, the photoresist has the exact shape of the intended pattern provided by the AC in the plane of the substrate having vertical walls passing through the resist. Thus, some parts of the substrate will be covered with resist and AC, and other parts will not be covered. The parts of the substrate covered with resist and AC act as a protective layer during etching, ion implantation, or other pattern transfer mechanisms, and are thus necessary for pattern transfer.

[0003] Since it is necessary to perform directional reactive ion etching for a long time to form a high aspect ratio structure, it is inevitable to avoid the gradual deterioration of AC. The deterioration of AC due to the etching process is promoted by the collision of ions with the surface of the side wall, and as a result, the shape and dimensions of the target etching layer may not be ensured.

[0004] In recent years, in order to reduce or eliminate the gradual deterioration of AC during reactive ion etching, carbonaceous materials such as polyamide and metal hard masks such as TiN and TaN have been introduced (see Non-Patent Documents 1 and 2). However, these materials are difficult to adapt to the patterning process because they require selectivity-inducing elements such as inhibitors, passivators, and self-assembled monolayers for selective formation on amorphous carbon, the residue layer grows on the mask due to the etching process, and the selectivity for selective formation on the mask is low, so they cannot be said to be ideal processes.

Prior Art Documents

Non-Patent Documents

[0005]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present disclosure aims to provide a method for forming a ruthenium-containing layer and a laminate that selectively form a ruthenium-containing layer as a protective layer on the surface of a mask for patterning formed on a substrate, which does not require the formation of a selectivity-inducing element and can suppress the generation of etching residues.

Means for Solving the Problems

[0007] As a result of intensive studies by the inventors of the present application, it was found that the above object can be achieved by adopting the following configuration, and the present invention was completed.

[0008] The present disclosure, in one embodiment, a preparation step of preparing a substrate having an oxidized layer; A deposition step of depositing a ruthenium-containing layer on the layer to be oxidized using ruthenium oxide by a vapor deposition method, including wherein the layer to be oxidized relates to a method for forming a ruthenium-containing layer and contains carbon atoms.

[0009] According to this formation method, a ruthenium-containing layer can be selectively deposited on the layer to be oxidized on a substrate having a layer to be oxidized (that is, a layer having the property of being oxidized). Ruthenium (Ru) has etching resistance against many plasma chemicals typically used for etching coating layers such as oxides, nitrides, and antireflection coating layers (for example, perfluorocarbon (PFC) gas, etc.). At the same time, ruthenium can be easily removed without generating residues by other plasma chemicals that do not remove the coating layer material. Therefore, the ruthenium-containing layer acts as a protective layer for the layer to be oxidized like a pattern mask during etching. As a result, it is possible to avoid mask degradation and reduce residue formation without the need for inhibitors or self-assembled monolayers (SAMs). Furthermore, the risk of pattern clogging and collapse can be reduced. Although the reason for this is not clear, ruthenium oxide (RuO4) is a powerful oxidizing agent applicable to gas-phase reactions and is presumably due to having a certain affinity with the layer to be oxidized.

[0010] Also, it is preferable that the layer to be oxidized contains carbon atoms. By the layer to be oxidized containing oxidizable carbon atoms or carbon-carbon bonds (that is, being an organic layer or a semi-organic layer), the affinity between ruthenium oxide and the layer to be oxidized is further improved. As a result, the selective formability of the ruthenium oxide layer on the layer to be oxidized can be further improved.

[0011] In one embodiment, the average composition of the ruthenium-containing layer may be RuOx. Here, the value of x is 0 or more and 2 or less. When the value of x is 0 (including the case of substantially 0), it means that a pure ruthenium layer is formed. Here, the average composition is obtained from the average by X-ray photoelectron spectroscopy. Specifically, by X-ray photoelectron spectroscopy, data for 3 repetitions can be acquired, and the average composition can be calculated from the average.

[0012] In one embodiment, it is preferable that the thickness of the ruthenium-containing layer formed per cycle of the deposition step is 0.05 nm or more and 0.20 nm or less. Also, in one embodiment, it is preferable that the thickness of the ruthenium-containing layer formed by the deposition step is 1 nm or more and 30 nm or less. By these, the mask protection function, strength, and productivity of the ruthenium-containing layer can be highly balanced.

[0013] In one embodiment, the forming method includes, in the deposition step, a first exposure in which the ruthenium oxide is exposed to the layer to be oxidized, and after the first exposure, a second exposure in which at least one co-reactant selected from the group consisting of hydrogen gas, ammonia gas, and hydrazine is exposed to the layer to be oxidized after the first exposure. It is preferable to perform the deposition cycle one or more times. In the deposition step, due to the action of ruthenium oxide, the carbon-carbon bonds in the layer to be oxidized are converted into oxidized groups such as epoxy, aldehyde, and ketone, and at the same time, ruthenium oxide species such as RuO2 are generated. Then, by reducing the oxidized groups and ruthenium oxide species with a co-reactant such as hydrogen gas, it is possible to bring about the precipitation of a ruthenium-containing layer having an average composition of RuOx (here, the value of x is 0 or more and 2 or less) in parallel with the reduction of the oxidized groups bonded to the layer to be oxidized.

[0014] In one embodiment, it is preferable that the substrate further has an oxide layer. Since ruthenium oxide does not show reactivity with an oxide layer that does not have the property of being oxidized, the selective formability of the ruthenium-containing layer on the layer to be oxidized can be further improved.

[0015] In one embodiment, the oxide layer may be a SiO2 layer, a SiN layer, a SiON layer, an Al2O3 layer, a ZrO2 layer, a TiO2 layer or a HfO2 layer. An appropriate oxide layer can be arranged according to the substrate application.

[0016] In one embodiment, it is preferable that the oxidized layer is an amorphous carbon layer, a boron-doped amorphous carbon layer, a tungsten-doped amorphous carbon layer, a photoresist layer or a halogen-containing porous low-k precursor layer. The amorphous carbon layer and the photoresist layer typically contain oxidizable sp 2 carbon atoms condensed as aromatic clusters or linked to another fragment or heteroatom. Also, the halogen-containing porous low-k precursor layer has sp 2 carbon atoms and sp 3 carbon atoms, or functional groups such as C-H bonds. Therefore, these oxidized layers can exhibit an affinity for the oxidation reaction by ruthenium oxide. As a result, a further improvement in the selective formability of the ruthenium-containing layer can be achieved. Here, the amorphous carbon layer means a layer substantially composed of amorphous carbon (alone). The boron-doped amorphous carbon layer means a layer composed of boron-doped amorphous carbon. The tungsten-doped amorphous carbon layer means a layer composed of tungsten-doped amorphous carbon.

[0017] In one embodiment, it is preferable that the oxidized layer is an amorphous carbon layer.

[0018] In one embodiment, the oxidized layer may be patterned. Even if the oxidized layer has a line-and-space or contact hole shape, a ruthenium oxide layer as a protective layer can be selectively formed, enabling protection of the oxidized layer.

[0019] In another embodiment, the present disclosure a preparation step of providing a substrate having an oxidized layer in a deposition chamber; a deposition step of introducing vaporized ruthenium oxide into the deposition chamber by a vapor phase growth method to deposit a ruthenium-containing layer on the oxidized layer; including wherein the oxidized layer relates to a method for forming a ruthenium-containing layer containing carbon atoms.

[0020] In another embodiment, the present disclosure a preparation step of preparing a substrate having an oxidized layer; a deposition step of forming a ruthenium-containing film on the oxidized layer by deposition by a vapor phase growth method of ruthenium oxide; including wherein the oxidized layer relates to a method for forming a ruthenium-containing layer containing carbon atoms.

[0021] In another embodiment, the present disclosure a substrate having an oxidized layer and an oxide layer on the surface; and a ruthenium-containing layer formed on the surface of the oxidized layer, wherein the oxidized layer relates to a laminate containing carbon atoms.

[0022] In the laminate, since a ruthenium-containing layer as a protective layer is selectively formed on the surface of the oxidized layer, it is possible to efficiently perform processing such as etching on the oxide layer while preventing deterioration of the oxidized layer.

[0023] It is preferable that the oxidized layer contains carbon atoms. By including oxidizable carbon atoms or carbon-carbon bonds in the oxidized layer, the affinity between ruthenium oxide and the oxidized layer is further improved, and the selective formability of the ruthenium-containing layer on the oxidized layer can be further improved.

[0024] In another embodiment, the oxidized layer is preferably an amorphous carbon layer, a boron-doped amorphous carbon layer, a tungsten-doped amorphous carbon layer, a photoresist layer, or a halogen-containing porous low-k precursor layer. Among these, the oxidized layer is preferably an amorphous carbon layer. These oxidized layers have oxidizable carbon atoms and can exhibit an affinity for the oxidation reaction by ruthenium oxide, and can further improve the selective formability of the ruthenium-containing layer.

[0025] In another embodiment, the thickness of the ruthenium-containing layer is preferably 1 nm or more and 30 nm or less. Thereby, the mask protection function, strength, and productivity of the ruthenium-containing layer can be highly balanced.

Brief Description of the Drawings

[0026]

Figure 1A

Figure 1B

Figure 1C

Figure 1D

Figure 2

Figure 3A

Figure 3B

Figure 4

Embodiments for Carrying Out the Invention

[0027] Embodiments of the present disclosure will be described below. The present invention is not limited to these embodiments.

[0028] 《Method for Forming Ruthenium-Containing Layer》 The method for forming a ruthenium-containing layer according to this embodiment includes a preparation step of preparing a substrate having an oxidized layer, and a deposition step of depositing a ruthenium-containing layer on the oxidized layer using ruthenium oxide by a vapor phase growth method. Hereinafter, as an example, a mode in which a laminate of a carbonaceous hard mask and a resist film is formed as an oxidized layer on a substrate, patterned, and then a ruthenium-containing layer as a protective layer is formed on the surface of the laminate will be described with reference to FIGS. 1A to 1D. FIGS. 1A to 1D are schematic cross-sectional views showing one step of the method for forming a ruthenium-containing layer according to one embodiment.

[0029] (Preparation Step) In this step, a substrate having an oxidized layer is prepared. As shown in FIG. 1A, on a semiconductor layer 10 as a substrate, a hard mask laminate (hereinafter, also referred to as an “ONON (oxide-nitride-oxide-nitride-nitride) laminate”) in which a sacrificial layer 20 (for example, a SiN layer) and an insulating layer 30 (for example, a SiO2 layer) are alternately laminated is formed. The number of laminations is appropriately set according to the substrate application. The ONON laminate can be formed by a CVD (Chemical Vapor Deposition) method or an ALD (Atomic Layer Deposition) method.

[0030] The substrate can be selected from oxides (e.g., HfO2-based materials, TiO2-based materials, ZrO2-based materials, rare earth oxide-based materials, ternary oxide-based materials, etc.) used as insulating materials in MIM, DRAM, or FeRam technologies, or from nitride-based films (e.g., TaN) used as oxygen barriers between copper substrates and low-k films. In the manufacture of semiconductors, photovoltaic cells, LCD-TFTs, or flat panel devices, other substrates can be used. Examples of such substrates include, but are not limited to, substrates such as metal nitride-containing substrates (e.g., TaN, TiN, SiN, WN, TaCN, TiCN, TaSiN, and TiSiN); insulators (e.g., SiO2, Si3N4, SiON, HfO2, Ta2O5, ZrO2, TiO2, Al2O3, and barium strontium titanate); or other substrates including some combinations of these materials.

[0031] Next, an organic carbonaceous layer 40 such as amorphous carbon is deposited on the ONON laminate. The organic carbonaceous layer 40 has an interface with the insulating layer 30 at the bottom. The organic carbonaceous layer can be deposited, for example, by CVD.

[0032] A resist composition is applied on the organic carbonaceous layer 40 to form a resist film, and the resist film is patterned to form a resist pattern 50. The resist pattern 50 is used, for example, to form line and space patterns or contact holes as part of a three-dimensional memory structure.

[0033] As shown in FIG. 1B, after the first etching step consisting of reactive ion etching (RIE), the organic carbonaceous layer 40 is processed using the resist pattern 50. The organic carbonaceous layer 40 and the resist pattern 50 are anisotropically etched, and the film thicknesses of both layers become thinner. The portion corresponding to the holes or patterns in the organic carbonaceous layer 40 is etched until the insulating layer 30 of the ONON laminate is exposed. Thereby, a substrate having an oxidized layer can be produced.

[0034] The substrate is not limited to the above. For example, many metals, i.e., transition metals, can occur in several different oxidation states. This means that they have the ability to undergo oxidation to form oxides. In addition, surfaces having C-H bonds, Si-Si bonds, Si-H bonds, Ge-Ge bonds, and Ge-H bonds are also suitable for selective formation. Therefore, the formation of the protective layer by the selective deposition method can be applied to a wide variety of substrates as long as ruthenium oxide is exposed to the oxidized surface.

[0035] (Deposition step) In this step, a ruthenium-containing film is deposited on the oxidized layer using ruthenium oxide by a vapor deposition method. In order to form holes or patterns that penetrate the organic carbonaceous layer 40 and the ONON laminate and reach the semiconductor layer 10, further long-time etching is required. Conventionally, during this process, the formation of residues from the resist pattern 50 and the organic carbonaceous layer 40 is promoted, which fall into unpenetrated holes or between patterns, increasing the risk of clogging between holes or patterns. Also, while ions collide with the surfaces of the resist pattern 50 and the organic carbonaceous layer 40, deformation of the holes or patterns occurs, resulting in the collapse of their shape features or structure.

[0036] In contrast, in this embodiment, in order to avoid the formation of polymer particles during the plasma etching process of the ONON laminate and other anti-reflection coating layers (not shown) in the next step, a material more resistant to the etching gas is used. That is, as shown in FIG. 1C, without depositing ruthenium on the insulating layer 30 located at the bottom of the ONON laminate, a ruthenium-containing layer is formed by selective deposition of ruthenium oxide (RuO4) by a vapor deposition method on the surfaces of both the resist pattern 50 and the organic carbonaceous layer 40 to protect them. At this time, ruthenium oxide reacts with the organic carbonaceous layer 40 to oxidize the surface layer of the layer. Ruthenium oxide can be accompanied by a solvent (e.g., methyl ethyl fluorinated solvent or tetrahydrofuran).

[0037] As the vapor deposition method, the ALD method or the CVD method can be preferably adopted. To remove contaminants from the substrate, a pretreatment step including oxygen plasma exposure for 1 second or more and 10 seconds or less may be performed. The deposition chamber may be any closed container or chamber of a device in which a vapor deposition method is executed internally. Specific examples include, but are not limited to, a parallel plate type reactor, a cold wall type reactor, a hot wall type reactor, a sheet type reactor, a multi-wafer reactor, or other types of deposition systems.

[0038] Next, a gas containing vaporized ruthenium oxide is introduced into the deposition chamber. Pure (single) ruthenium oxide or ruthenium oxide blended with other components may be supplied to the vaporizer in a liquid state. Before being introduced into the deposition chamber, it is vaporized by bubbling a carrier gas. If necessary, the container may be heated to a temperature at which ruthenium oxide has a sufficient vapor pressure and is below the decomposition temperature. Examples of the carrier gas include, but are not limited to, Ar, He, N2, and mixtures thereof. The container can be maintained at a temperature preferably in the range of 50°C or more and 300°C or less, more preferably 80°C or more and 200°C or less.

[0039] The ruthenium oxide in the deposition chamber can be maintained at a pressure preferably in the range of 0.1 Pa or more and 2 Pa or less, more preferably 0.2 Pa or more and 1.5 Pa or less.

[0040] Ruthenium oxide can be supplied in a pure form (e.g., liquid or low melting point solid) or in the form of a blend with a suitable solvent. The solvent may be a non-flammable solvent or a flammable solvent. Examples of the solvent include, for example, methyl ethyl fluorinated solvent, tetrahydrofuran, etc. A mixed solvent of various solvents may also be used.

[0041] The lower limit of the thickness of the ruthenium oxide layer formed per cycle of the deposition process is preferably 0.05 nm, more preferably 0.10 nm, and even more preferably 0.15 nm. The upper limit of the thickness per cycle of the deposition process is preferably 0.30 nm, more preferably 0.25 nm, and even more preferably 0.20 nm.

[0042] The lower limit of the thickness of the ruthenium-containing layer formed by the deposition process is preferably 1 nm, more preferably 2 nm, even more preferably 4 nm, and particularly preferably 5 nm. The upper limit of the thickness of the ruthenium oxide layer is preferably 30 nm, more preferably 28 nm, even more preferably 26 nm, and particularly preferably 24 nm.

[0043] In the deposition process, it is preferable to perform one or more deposition cycles including a first exposure of exposing the ruthenium oxide to the layer to be oxidized, and after the first exposure, a second exposure of exposing at least one co-reactant selected from the group consisting of hydrogen gas, ammonia gas, and hydrazine to the layer to be oxidized after the first exposure. A co-reactant such as hydrogen gas can bring about the precipitation of a layer of RuOx (the value of x is 0 or more and 2 or less) in parallel with the reduction of the oxidized groups bonded to the layer to be oxidized.

[0044] Therefore, the ALD process for depositing a ruthenium-containing layer can include a step of exposing a substrate to a first reactant in one deposition cycle, a step of removing unreacted first reactant and reaction by-products from the reaction space, a step of exposing the substrate to a second reactant, and a subsequent second removal step. For example, the first reactant can include ruthenium oxide (RuO4), and the second reactant can include hydrogen (H2) gas. This one deposition cycle may be repeated until a desired ruthenium-containing layer is obtained.

[0045] Hydrogen gas as a co-reactant is preferably introduced into the deposition chamber together with a carrier gas. As the carrier gas, the carrier gas used when introducing ruthenium oxide can be preferably employed. Among them, argon (Ar) is preferable.

[0046] The lower limit of the volume ratio of hydrogen gas in the total volume of hydrogen gas and argon gas is preferably 5%, more preferably 10%, and even more preferably 15%. The upper limit of the volume ratio of the hydrogen gas is preferably 90%, more preferably 50%, and even more preferably 30%. Also, the hydrogen gas may be 100%. Further, nitrogen gas may be used instead of argon gas.

[0047] The partial pressure of hydrogen gas in the deposition chamber can be maintained at a pressure preferably in the range of 100 Pa or more and 800 Pa or less, more preferably 200 Pa or more and 600 Pa or less.

[0048] After a ruthenium-containing layer (ruthenium-containing layer having an average composition of RuOx (where the value of x is 0 or more and 2 or less) or a pure ruthenium layer) is deposited on both surfaces of the organic carbonaceous layer 40 and the resist pattern 50 as a protective layer, as shown in FIG. 1D, the sacrificial template can be transferred to the substrate without accumulating residues on the sidewalls of the pattern by further etching.

[0049] The ruthenium-containing layer is converted into a ruthenium oxide (RuO4) layer that does not leave residues by other plasma chemicals that do not remove nitrides, oxides, and ARC materials, for example, oxygen plasma. This ruthenium oxide layer can be easily purged from the deposition chamber and can be easily removed.

[0050] FIG. 2 shows a proposed mechanism of a series of reactions on the surface of the organic carbonaceous layer from the formation to the removal of the ruthenium-containing layer. However, the present invention is not limited to this proposed mechanism.

[0051] The surface of the oxidized layer (for example, the organic carbonaceous layer 40) formed on the substrate has carbon atoms (in state a) in FIG. 2).

[0052] By oxidizing the surface of the organic carbonaceous layer 40 with ruthenium oxide (RuO4), carbon atoms and carbon-carbon bonds are converted into oxidized groups such as epoxy, aldehyde, and ketone, and at the same time, ruthenium oxide species such as RuO2 are generated (in Figure 2, state b)).

[0053] Next, during reduction with hydrogen gas as a co-reactant, it is possible to bring about the precipitation of a pure ruthenium layer in parallel with the reduction of the oxygen-containing functional groups bonded to the organic carbonaceous layer 40 (in Figure 2, state c)).

[0054] Thereafter, the ruthenium-containing layer (ruthenium layer) can be removed from the surface of the organic carbonaceous layer 40 by subjecting it to oxygen plasma treatment to form a ruthenium oxide (RuO4) layer and then purging (in Figure 2, state d)).

[0055] For the plasma cleaning conditions for removing the ruthenium layer, the pressure of oxygen gas is preferably 0.1 Pa or more and 1.5 Pa or less, more preferably 0.2 Pa or more and 1.0 Pa or less. The power is preferably 100 W or more and 500 W or less, more preferably 200 W or more and 300 W or less. The plasma treatment time is preferably 1 second or more and 50 seconds or less, more preferably 5 seconds or more and 20 seconds or less.

[0056] (Other oxidized layers) When the material is not reactive or not very reactive to oxidation and thus has low reactivity to ruthenium oxide (RuO4), those skilled in the art may recognize that selective formation of a ruthenium-containing layer can occur by modifying or introducing oxide functional groups into the layer to be protected. For example, some already oxidized or unreacted low-k or ULK layers can become reactive to ruthenium oxide (RuO4) when filled with sacrificial organic halogen (e.g., BCHD or ATRP) before being exposed to ultraviolet light required to introduce porosity into these layers.

[0057] The halogenated organic carbonaceous material has a strong affinity for oxidation sp 2 and sp 3It has functional groups such as carbon-carbon bonds and carbon-hydrogen bonds. Therefore, ruthenium oxide (RuO4) as a strong oxidizing agent can selectively react with the halogenated organic carbonaceous material, and a ruthenium-containing layer can be selectively deposited as a protective layer.

[0058] 《Laminate》 The laminate according to this embodiment has a substrate having an oxidized layer and an oxide layer on its surface, and a ruthenium-containing layer formed on the surface of the oxidized layer. Here, the oxidized layer contains carbon atoms. Such a structure corresponds to the structure of FIG. 1C shown in the description of the method for forming the ruthenium-containing layer (note that in FIG. 1C, although the ruthenium-containing layer is a ruthenium layer, it is not limited thereto, and the average composition may be RuOx (the value of x is 0 or more and 2 or less)). Therefore, for the preferred embodiments of each element, refer to the corresponding parts of the above description made with reference to FIGS. 1A to 1D and FIG. 2.

[0059] 《Other Embodiments》 One embodiment of the present invention relates to a method and a precursor useful for manufacturing an electronic device. More specifically, it relates to depositing a ruthenium film on a substrate. It relates to a method for protecting a layer during an etching process involved in multiple patterning and self-alignment techniques for forming contacts, vias, memory holes, and other stacked layers.

[0060] One embodiment of the present invention relates to a method consisting of the use of a ruthenium precursor containing RuO4 for selectively depositing a ruthenium or ruthenium-containing film on an organic layer or a semi-organic layer without depositing it on an inorganic layer.

[0061] The Ru film is selectively deposited by chemical vapor deposition (CVD) or atomic layer deposition (ALD) on an organic or semi-organic carbonaceous layer without the need for an inhibitor or self-assembled monolayer (SAM), and then acts as an etching hard mask during the etching process, which is the next step for patterning the target layer. The ruthenium layer produced by this method is also used to reduce the spacing between lines of the organic layer or semi-organic layer, and thus to provide the opposite trimming effect of the transferred pattern structure.

[0062] One embodiment of the present invention relates to a method for efficiently forming a structure having improved mechanical strength in logic, transistor, and memory devices as compared to multi-patterning and self-aligned patterning techniques. The ruthenium-containing layer deposited by this method is deposited on selected regions on the substrate so as to act as a protective layer for the hard mask in order to avoid damage to the hard mask during the etching process, which is a step of lithography.

Example

[0063] To illustrate the application of the disclosure herein, the following examples are described, but it should be fully understood that not all of the advantages of the processes described herein may be included in a particular embodiment or group of embodiments of the present invention. Although specific embodiments and examples are disclosed below, it will be understood by those skilled in the art that the present invention extends beyond the specifically disclosed embodiments and / or uses of the present invention, including obvious modifications. Accordingly, it should be understood that the scope of the present invention as disclosed should not be limited by the specific embodiments described below.

[0064] <Example 1> A substrate (purchased from Advantech Co., Ltd.) was prepared, on which an SiO2 layer (3 μm thick) and an amorphous carbon layer (700 nm thick, with contact holes having a diameter of 140 - 160 nm formed at 100 nm intervals) were successively formed. This substrate was placed in a chamber heated to a temperature below the decomposition temperature of ruthenium oxide (RuO4) (100 °C), and an ALD method cycle was performed in which the vapor of ruthenium oxide was passed through. As cycle conditions, RuO4 was pulsed into the chamber at 0.8 Pa for 10 seconds, and the excess unreacted gas was purged from the chamber. Next, hydrogen gas with a partial pressure of 500 Pa (20% H2 / Ar (volume ratio)) was added as a co-reactant for 10 seconds to reduce the ruthenium oxide layer during the surface reaction to form a ruthenium layer (with x = 0 in the average composition RuOx).

[0065] According to the above method, the thickness of the ruthenium layer followed a growth rate in the range of 0.07 nm to 0.19 nm per cycle.

[0066] As a result, after 30 ALD method cycles, a 2.30 nm ruthenium layer was selectively deposited on the amorphous carbon layer. On the other hand, no ruthenium layer was deposited on the SiO2 layer. Figure 3A is an electron micrograph (magnification: 120,000 times) of a ruthenium-containing layer containing only ruthenium formed on the surface of the amorphous carbon layer. Figure 3B is an electron micrograph (magnification: 100,000 times) of the surface of the SiO2 layer. As the electron microscope, Hitachi UHR FE-SEM SU9000 manufactured by Hitachi High-Tech Corporation was used.

[0067] Figure 4 is a secondary ion mass spectrometry chart of a ruthenium-containing layer containing only ruthenium formed on the surface of the amorphous carbon layer. For secondary ion mass spectrometry, PHI ADEPT1010 of ULVAC-PHI, Inc. was used. The measurement conditions are as follows. · Primary ion species: Cs + · Primary acceleration voltage: 2.0 kV · Detection area: 132×132 (μm×μm) The measured results are shown in Fig. 4. The horizontal axis in Fig. 4 represents the depth from the surface (nm), and the vertical axis represents the ratio (%) of various elements. It can be seen that ruthenium exists alone up to a depth of about 4 nm from the surface of the ruthenium-containing layer, indicating that a ruthenium layer with high purity was formed.

[0068] The conditions for plasma cleaning for the removal of the ruthenium layer were 5 pulses of O2 plasma for 10 seconds using O2 gas with a purity of 99.999% at a pressure of 0.5 Pa and a power of 250 W.

[0069] <Example 2> Similar to Example 1, as a result of performing 60 ALD method cycles, an 8.44-nm ruthenium layer was selectively deposited on the amorphous carbon layer. On the other hand, no ruthenium layer was deposited on the SiO2 layer.

[0070] <Example 3> Similar to Example 1, as a result of performing 120 ALD method cycles, a 22.48-nm ruthenium layer was selectively deposited on the amorphous carbon layer. On the other hand, no ruthenium layer was deposited on the SiO2 layer.

Explanation of reference numerals

[0071] 10 Semiconductor layer 20 Sacrificial layer (SiN layer) 30 Insulating layer (SiO2 layer) 40 Organic carbonaceous layer (amorphous carbon layer) 50 Resist pattern 60 Ruthenium-containing layer (ruthenium layer)

Claims

1. A preparation step of preparing a substrate having an oxidized layer; A deposition step of depositing a ruthenium-containing layer on the oxidized layer using ruthenium oxide by a vapor deposition method; comprising; wherein the oxidized layer is an amorphous carbon layer, a boron-doped amorphous carbon layer, a tungsten-doped amorphous carbon layer, a photoresist layer or a halogen-containing porous low-k precursor layer, a method for forming a ruthenium-containing layer.

2. The average composition of the ruthenium-containing layer is RuOx (where the value of x is 0 or more and 2 or less), the method for forming a ruthenium-containing layer according to claim 1.

3. The thickness of the ruthenium-containing layer formed in the deposition step is 0.05 nm or more and 0.30 nm or less, the method for forming a ruthenium-containing layer according to claim 1 or 2.

4. In the deposition step, a first exposure of exposing the ruthenium oxide to the oxidized layer, and after the first exposure, a second exposure of exposing at least one co-reactant selected from the group consisting of hydrogen gas, ammonia gas, and hydrazine to the oxidized layer after the first exposure. The deposition cycle is performed once or twice or more, the method for forming a ruthenium-containing layer according to any one of claims 1 to 3.

5. The substrate further has an oxide layer, the method for forming a ruthenium-containing layer according to any one of claims 1 to 4.

6. The oxide layer is a SiO2 layer, a SiN layer, a SiON layer, an Al2O3 layer, a ZrO2 layer, a TiO2 layer or a HfO2 layer, the method for forming a ruthenium-containing layer according to claim 5.

7. The method for forming a ruthenium-containing layer according to any one of claims 1 to 6, wherein the oxidized layer is an amorphous carbon layer.

8. The method for forming a ruthenium-containing layer according to any one of claims 1 to 7, wherein the oxidized layer is patterned.

9. A substrate having an oxidized layer and an oxide layer on the surface; A ruthenium-containing layer formed on the surface of the oxidized layer; having; wherein the oxidized layer is an amorphous carbon layer, a photoresist layer, a boron-doped amorphous carbon layer, a tungsten-doped amorphous carbon layer or a halogen-containing porous low-k precursor layer, a laminate.

10. The average composition of the ruthenium-containing layer is RuOx (where the value of x is 0 or more and 2 or less), the laminate according to claim 9.

11. The laminate according to claim 9 or 10, wherein the oxidized layer is an amorphous carbon layer.

12. The laminate according to any one of claims 9 to 11, wherein the ruthenium-containing layer has a thickness of 1 nm or more and 30 nm or less.

Images