Method for forming a regionally selective film with a selection agent

Abstract

According to an embodiment of the present application, a method for forming a region-selective thin film includes: a selection agent supplying step of supplying a selection agent to an inside of a chamber in which a substrate is placed, to cause the selection agent to be adsorbed to a non-growth region of the substrate; a purging step of purging the inside of the chamber; a precursor supplying step of supplying a precursor to the inside of the chamber, to cause the precursor to be adsorbed to a growth region of the substrate; a purging step of purging the inside of the chamber; and a thin film forming step of supplying a reaction material to the inside of the chamber, to cause the reaction material to react with the adsorbed metal precursor to form a thin film.

Description

Technical Field

[0001] The present invention relates to a method for forming a thin film, and more particularly, to a method for forming a regionally selective thin film using a selective agent. Background Technology

[0002] With the development of innovative technologies, DRAM devices have continued to miniaturize, reaching the 10nm era. Accordingly, in order to improve performance and reliability, even with the reduction in capacitor size, it is necessary to maintain high capacitance and low leakage current characteristics, and the breakdown voltage must be high.

[0003] Various studies are underway to increase the capacitance of conventional high-k materials, and a method exists that utilizes a seed layer to aid in the crystallization of the dielectric layer.

[0004] This method can form crystal structures with high dielectric constants even at relatively low temperatures, but there is a problem that seed layers can be deposited where dielectric films should not be deposited, resulting in leakage current. Summary of the Invention

[0005] The technical problem that the invention aims to solve

[0006] One object of the present invention is to provide a method for forming a thin film with high capacitance.

[0007] Another object of the present invention is to provide a thin film formation method that can minimize leakage current.

[0008] Another object of the present invention is to provide a method for forming a thin film for selectable regions.

[0009] Other objects of the present invention will become clear in the following detailed description.

[0010] Problem Solution

[0011] According to an embodiment of the present invention, a method for forming a region-selective thin film includes: a selector supply step of supplying a selector to the interior of a chamber in which a substrate is disposed, such that the selector is adsorbed onto a non-growth region of the substrate; a purification step of purifying the interior of the chamber; a precursor supply step of supplying a precursor to the interior of the chamber, such that the precursor is adsorbed onto a growth region of the substrate; a purification step of purifying the interior of the chamber; and a thin film forming step of supplying a reactant to the interior of the chamber, such that the reactant reacts with the adsorbed precursor to form a thin film, wherein the selector is represented by the following chemical formula 1:

[0012] <Chemical Formula 1>

[0013]

[0014] In <Chemical Formula 1>, n is an integer from 0 to 8, R1-R3 are each selected from alkyl groups having 1 to 8 carbon atoms, and R4 is selected from hydrogen, alkyl groups having 1 to 8 carbon atoms, and alkoxy groups having 1 to 8 carbon atoms.

[0015] In <Chemical Formula 1>, n is an integer from 0 to 8, R1 to R3 are each selected from alkyl groups having 1 to 8 carbon atoms, and R4 is selected from hydrogen, alkyl groups having 1 to 8 carbon atoms, and alkoxy groups having 1 to 8 carbon atoms.

[0016] The growth region is a titanium nitride film or a niobium nitride film.

[0017] The non-growth area is a silicon nitride film.

[0018] The silicon nitride film is selected from one or more of SiN, SiCN, C-doped SiN, and SiON.

[0019] The reactants are selected from O3, O2, and H2O.

[0020] The precursor is selected from one or more of the IIIA, IVB, and VB groups.

[0021] The thin film is formed by metal-organic chemical vapor deposition (MOCVD) or atomic layer deposition (ALD).

[0022] According to an embodiment of the present invention, a method for forming a region-selective thin film includes: a selectant supply step of supplying a selectant to the interior of a chamber in which a substrate is disposed, such that the selectant is adsorbed onto a non-growth region of the substrate; a purification step of purifying the interior of the chamber; a precursor supply step of supplying a precursor to the interior of the chamber, such that the precursor is adsorbed onto a growth region of the substrate; a purification step of purifying the interior of the chamber; and a thin film forming step of supplying a reactant to the interior of the chamber, such that the reactant reacts with the adsorbed precursor to form a thin film, wherein the growth region is a titanium nitride film or a niobium nitride film, the non-growth region is a silicon nitride film, and the selectant is trimethyl orthoformate.

[0023] Invention Effects

[0024] According to one embodiment of the present invention, while the selector is adsorbed into the non-growth region, the subsequent supply of precursor is prevented from being adsorbed into the non-growth region, thereby preventing the formation of a thin film in the non-growth region. Furthermore, this minimizes leakage current. Attached Figure Description

[0025] Figure 1 A flowchart illustrating a thin film formation method according to an embodiment of the present invention is provided.

[0026] Figure 2 To illustrate the basis Figure 1 A graph of the supply cycle.

[0027] Figure 3 To illustrate the point, based on Figure 1 A diagram illustrating the thin film formation process.

[0028] Figure 4 A graph showing the niobium content obtained from X-ray photoelectron spectroscopy analysis according to an embodiment of the present invention and Comparative Example 1.

[0029] Figure 5 The table shows the thickness reduction rate of an embodiment of the present invention, with Comparative Example 1 as a benchmark. Detailed Implementation

[0030] In the following text, we will utilize Figures 1 to 5 The embodiments of the present invention are described below. The embodiments of the present invention may include various modifications, and the scope of the invention should not be construed as limited to the following embodiments. These embodiments are provided to explain the invention in more detail to those skilled in the art. Therefore, the shapes of the components shown in the drawings may be exaggerated to emphasize a clearer description.

[0031] In this specification, unless otherwise stated, when a component “includes” a certain component, it means that it may further include other components rather than exclude other components.

[0032] The terms "about," "substantially," etc., used in this specification to indicate degree, when referring to inherent manufacturing and material tolerances, mean numerical values ​​or close to their values, and are intended to prevent unscrupulous infringers from misusing the disclosed content involving accurate or absolute values.

[0033] In this specification, the term "alkane" or "alkyl" refers to a straight-chain or branched alkyl group having 1 to 12 carbon atoms, 1 to 10 carbon atoms, 1 to 8 carbon atoms, 1 to 5 carbon atoms, 1 to 3 carbon atoms, 3 to 8 carbon atoms, or 3 to 5 carbon atoms. For example, alkyl groups include methyl, ethyl, n-propyl (nPr), isopropyl (iPr), n-butyl (nBu), tert-butyl (tBu), isobutyl (iBu), sec-butyl (sBu), n-pentyl, tert-pentyl, isopentyl, sec-pentyl, neopentyl, 3-pentyl, hexyl, isohexyl, heptyl, 4,4-dimethylpentyl, octyl, 2,2,4-trimethylpentyl, nonyl, decyl, undecyl, dodecyl, and their isomers, but are not limited thereto.

[0034] The term "membrane" as used in this specification may include, but is not limited to, "thin film".

[0035] In existing processes, the following problem exists: dielectric films are deposited in non-growth areas (e.g., on non-metallic films such as silicon nitride films), leading to leakage current. However, the selector described below is adsorbed onto non-metallic films (e.g., silicon nitride films) at a higher density than that of metal films, and this selector hinders the adsorption of subsequently added metal precursors, so that the seed layer is formed only on the metal film.

[0036] Figure 1 A flowchart illustrating a thin film formation method according to an embodiment of the present invention is provided. Figure 2 To illustrate the basis Figure 1 A graph of the supply cycle. Figure 3 To illustrate the point, based on Figure 1 A diagram illustrating the thin film formation process.

[0037] Load the substrate into the process chamber and adjust the following ALD process conditions. ALD process conditions may include the temperature of the substrate or process chamber, the pressure in the process chamber, the gas flow rate, and the temperature is between 10 and 900°C.

[0038] The substrate is exposed to a selectant supplied to the cavity, which is adsorbed onto the surface of a non-growth region of the substrate. The non-growth region may be a silicon nitride layer, and may be at least one selected from SiN, SiCN, carbon-doped SiN, and SiON. The selectant is adsorbed at a high density onto the surface of the non-growth region, hindering the adsorption of metal precursors in subsequent processes.

[0039] The selector can be represented by the following chemical formula 1:

[0040] <Chemical Formula 1>

[0041]

[0042] In <Chemical Formula 1>, n is an integer from 0 to 8, R1-R3 are each selected from alkyl groups having 1 to 8 carbon atoms, and R4 is selected from hydrogen, alkyl groups having 1 to 8 carbon atoms, and alkoxy groups having 1 to 8 carbon atoms.

[0043] Subsequently, a purifying gas (e.g., an argon gas such as Ar) is supplied to the interior of the chamber to remove or purify the unadsorbed selective agent or byproducts.

[0044] The substrate is then exposed to a metal precursor supplied to the chamber. The metal precursor is adsorbed onto the surface of the growth region of the substrate but not onto the surface of the non-growth region due to the selector. The metal precursor may include Group 3, such as Al; or Group 4, such as Zr or Hf; or Group 5, such as Nb or Ta.

[0045] Subsequently, a purifying gas (e.g., an volatile gas, such as Ar) is supplied to the interior of the chamber to remove or purify unadsorbed metal precursors or byproducts.

[0046] The substrate is then exposed to a reactive substance supplied to the chamber to form a thin film on its surface. The reactive substance reacts with a metal precursor to form the film; the reactive substance can be selected from O3, O2, or H2O. A metal oxide layer can be formed from the reactive substance. At this point, the reactive substance oxidizes the adsorbed surface-protecting substance to separate and remove it from the substrate surface.

[0047] Subsequently, a purifying gas (e.g., an volatile gas, such as Ar) is supplied to the interior of the chamber to remove or purify unreacted materials or byproducts.

[0048] On the other hand, as described above, the selector is supplied before the metal precursor, but the selector may be supplied after the metal precursor, or the metal precursor may be supplied both before and after the selector.

[0049] Example 1

[0050] Trimethyl orthoformate was used as a selector to form niobium oxide films on both TiN and SiN thin-film substrates. The niobium oxide films were formed via an ALD process at a temperature of 290°C, using ozone gas (O3) as the reactant.

[0051] The process of forming a niobium oxide film by the ALD process is shown below, with the following process executed as one cycle (refer to...). Figures 1 to 3 ).

[0052] 1) The selector is supplied into the reaction chamber to be adsorbed onto the substrate.

[0053] 2) Supply Ar gas into the reaction chamber to remove unadsorbed selectants or byproducts.

[0054] 3) Using Ar as a carrier gas, the niobium precursor (TBTDEN, tert-butylimine tris(diethylamide)niobium) is supplied to the reaction chamber, so that the niobium precursor is adsorbed onto the substrate.

[0055] 4) Ar gas is supplied to the reaction chamber to remove unadsorbed niobium precursors or byproducts.

[0056] 5) Supply ozone gas (O3) into the reaction chamber to form a niobium oxide film.

[0057] 6) Ar gas is supplied to the reaction chamber to remove unreacted substances or byproducts.

[0058] -Comparative Example 1

[0059] Without using the aforementioned selector, niobium oxide films were formed on both a TiN (metal thin film) substrate and a SiN (non-metal thin film) substrate. The niobium oxide films were formed via an ALD (Alternating Discharge) process at a temperature of 290°C, using ozone gas (O3) as the reactant.

[0060] The process of forming a niobium oxide film via ALD is as follows, with each of the following processes constituting one cycle of the process.

[0061] 1) Ar is used as the carrier gas to supply the niobium precursor (TBTDEN, tert-butylimine tri(diethylamide)niobium) to the reaction chamber, so that the niobium precursor is adsorbed onto the substrate.

[0062] 2) Ar gas is supplied to the reaction chamber to remove unadsorbed niobium precursors or byproducts.

[0063] 3) Supply ozone gas (O3) into the reaction chamber to form a niobium oxide film.

[0064] 4) Ar gas is supplied to the reaction chamber to remove unreacted substances or byproducts.

[0065] -Comparison Example 2

[0066] Except that the selector was changed from trimethyl orthoformate to ethanol, the niobium oxide film was formed in the same manner as in Example 1.

[0067] Figure 4 The diagram illustrates the niobium content obtained from X-ray photoelectron spectroscopy analysis (based on 30 periods) according to an embodiment of the present invention and Comparative Example 1. In Comparative Example 1, the niobium content is SiN substrate:TiN substrate = 1:1.2; while in Example 1, the niobium content is SiN:TiN = 1:3.2, showing increased selectivity. This result can be explained by the selective agent being adsorbed onto the SiN substrate to suppress the deposition of the niobium precursor.

[0068] Figure 5 The table shows the thickness reduction rate of an embodiment of the present invention, with Comparative Example 1 as a reference. Figure 5 As shown, the niobium oxide film of Example 1 exhibits a 42% reduction in thickness on the TiN substrate and an 82% reduction in thickness on the SiN substrate, confirming an increase in selectivity. The selectivity of the selector in Example 1 is attributed to its structural compatibility with the SiN substrate, resulting in enhanced adsorption force, which is explained as delaying the nucleation growth of the metal film on the SiN substrate. Furthermore, the desired selectivity is achieved as a result of other combined factors.

[0069] In summary, the selective agent exhibits a high thickness reduction effect through selective adsorption of non-metallic thin films, thereby imparting selectivity to deposit dielectric films on desired areas of the substrate and preventing the formation of thin films in unwanted areas, thus minimizing leakage current.

[0070] The present invention has been explained in detail with reference to the embodiments, but may include other embodiments. Therefore, the technical concepts and scope described in the following claims are not limited to the embodiments.

[0071] Industrial applicability

[0072] This invention can be applied to various semiconductor manufacturing methods.

Claims

1. A method of forming a region-selective thin film, comprising: a selection agent supplying step of supplying a selection agent to an inside of a chamber in which a substrate is placed inside, to cause the selection agent to be adsorbed to a non-growth region of the substrate; a purging step of purging the inside of the chamber; a precursor supplying step of supplying a precursor to the inside of the chamber, to cause the precursor to be adsorbed to a growth region of the substrate; a purging step of purging the inside of the chamber; and a thin film forming step of supplying a reaction material to the inside of the chamber, to cause the reaction material to react with the adsorbed precursor to form a thin film, the selection agent being represented by the following Chemical Formula 1: <Chemical Formula 1> in Chemical Formula 1, n is each an integer of 0 to 8, R1 to R3 are each selected from an alkyl group having 1 to 8 carbon atoms, and R4 is selected from hydrogen, an alkyl group having 1 to 8 carbon atoms, and an alkoxy group having 1 to 8 carbon atoms.

2. The method of forming a region-selective thin film according to claim 1, wherein the growth region is a titanium nitride film or a niobium nitride film.

3. The method of forming a region-selective thin film according to claim 1, wherein the non-growth region is a silicon nitride film.

4. The method of forming a region-selective thin film according to claim 3, wherein the silicon nitride film is one or more selected from SiN, SiCN, C-doped SiN, and SiON.

5. The method of forming a region-selective thin film according to claim 1, wherein the reaction material is selected from O3, O2, and H2O.

6. The method of forming a region-selective thin film according to claim 1, wherein the precursor is one or more selected from Group IIIA, Group IVB, and Group VB.

7. The method of forming a region-selective thin film according to claim 1, wherein the thin film is formed by metal organic chemical vapor deposition (MOCVD) or atomic layer deposition (ALD).

8. A method of forming a region-selective thin film, comprising: a selection agent supplying step of supplying a selection agent to an inside of a chamber in which a substrate is placed inside, to cause the selection agent to be adsorbed to a non-growth region of the substrate; a purging step of purging the inside of the chamber; a precursor supplying step of supplying a precursor to the inside of the chamber, to cause the precursor to be adsorbed to a growth region of the substrate; a purging step of purging the inside of the chamber; and a thin film forming step of supplying a reaction material to the inside of the chamber, to cause the reaction material to react with the adsorbed precursor to form a thin film, the growth region being a titanium nitride film or a niobium nitride film, the non-growth region being a silicon nitride film, and the selection agent being trimethyl orthoformate. ​ ​

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