Method of forming thin film using chemical masking agent, semiconductor device manufactured thereby, and method of manufacturing semiconductor device including same

Abstract

According to an embodiment of the present invention, a method for forming a thin film using a chemical masking agent comprises: a chemical masking agent supply step for supplying a chemical masking agent to the inside of a chamber in which a substrate is placed, and thereby adsorbing the chemical masking agent to the substrate; a step for purging the inside of the chamber; a metal precursor supply step for supplying a metal precursor, which is a compound containing a hexavalent metal including Mo, to the inside of the chamber to adsorb the metal precursor to the substrate; a step for purging the inside of the chamber; and a thin film forming step for supplying a reactant to the inside of the chamber so that the reactant reacts with the adsorbed metal precursor to form a thin film.

Description

Method for forming a thin film using a chemical masking agent, a semiconductor device manufactured thereby, and a method for manufacturing a semiconductor device including the same

[0001] The present invention relates to a method for forming a thin film, a semiconductor device, and a method for manufacturing a semiconductor device. More specifically, it relates to a method for forming a thin film using a chemical masking agent, a semiconductor device manufactured through the same, and a method for manufacturing a semiconductor device including the same.

[0002] Currently, research on NAND Flash word lines is continuously being conducted, and tungsten (W Metal) is widely used as a word line material.

[0003] As NAND enters the late 200-layer range, the tungsten (W) resistance increases due to the reduction in the thickness of the metal wiring, and there is a problem in which holes occur due to the etching (SiO2 etch) of the underlying silicon oxide film caused by HF generation when depositing a W thin film using a tungsten precursor (WF6 Precursor).

[0004] To address these issues, the development of a Mo thin film process using molybdenum dichloride dioxide (MoO2Cl2), which does not contain the F ligand of the precursor itself and has lower resistivity than W, is underway.

[0005] In the case of molybdenum dichloride dioxide (MoO2Cl2), due to its high reactivity, it is adsorbed relatively heavily onto the upper surface of the pattern during thin film formation, making it difficult to form a conformal thin film and causing degradation of step coverage and seam formation; therefore, a technology capable of resolving these phenomena is required.

[0006] The object of the present invention is to provide a method for forming a thin film with good step coverage, and also to provide a method for forming a bottom-up filing thin film, a semiconductor device manufactured thereby, and a method for manufacturing a semiconductor device including the same.

[0007] Another objective of the present invention is to provide a thin film formation method capable of significantly improving step coverage by reducing the adsorption amount of a highly reactive precursor, a semiconductor device manufactured thereby, and a method for manufacturing a semiconductor device including the same.

[0008] Other objects of the present invention will become more apparent from the following detailed description.

[0009] According to one embodiment of the present invention, a method for forming a thin film using a chemical masking agent comprises: a chemical masking agent supply step of supplying a chemical masking agent into the interior of a chamber on which a substrate is placed to adsorb the chemical masking agent onto the substrate; a step of purging the interior of the chamber; a metal precursor supply step of supplying a metal precursor, which is a compound containing a hexavalent metal including Mo, into the interior of the chamber to adsorb the metal precursor onto the substrate; and a thin film forming step of supplying a reaction material into the interior of the chamber to react with the adsorbed metal precursor and form a thin film.

[0010] The above chemical masking agent can be represented by the following <Chemical Formula 1>.

[0011] <Chemical Formula 1>

[0012]

[0013] In the above <Chemical Formula 1>, R1 to R4 are each independently selected from hydrogen, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an arylalkyl group having 6 to 12 carbon atoms.

[0014] In the above <Chemical Formula 1>, when R1 to R4 are alkyl groups having 1 carbon atom (specifically, methyl groups), the chemical masking agent corresponds to 2,3-dimethyl-2-butene.

[0015] The above chemical masking agent can be represented by the following <Chemical Formula 2>.

[0016] <Chemical Formula 2>

[0017]

[0018] In the above <Chemical Formula 2>, X is a carbon or nictogen element (N, P, As, Sb, Bi), and R1 to R6 are each independently selected from hydrogen having 0 to 1 carbon, an alkyl group having 1 to 8 carbons, a cycloalkyl group having 3 to 6 carbons, an aryl group having 6 to 12 carbons, a halogen element, an alkyl halide, or a cyano group.

[0019] In the above <Chemical Formula 2>, where X is carbon, R1 is absent, R2, R4, and R6 are alkyl groups with one carbon atom (specifically, methyl groups), and R3 and R5 are hydrogen, the above chemical masking agent corresponds to Mesitylene.

[0020] In the above <Chemical Formula 2>, where X is carbon, R1 is absent, R2, R3, R4, R6 are hydrogen, and R5 is an alkyl group having 3 carbon atoms (specifically, propene), the above chemical masking agent corresponds to Allyl Benzene.

[0021] The above chemical masking agent can be represented by the following <Chemical Formula 3>.

[0022] <Chemical Formula 3>

[0023]

[0024] In the above <Chemical Formula 3>, R1 is selected from hydrogen, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and an aryl group having 6 to 12 carbon atoms.

[0025] In the above <Chemical Formula 3>, when R1 is an alkyl group having 5 carbon atoms (specifically, 2-methylbutane), the chemical masking agent corresponds to Tert-amyl alcohol (TAA).

[0026] The above chemical masking agent can be represented by the following <Chemical Formula 4>.

[0027] <Chemical Formula 4>

[0028]

[0029] In the above <Chemical Formula 4>, R1 or R2 is each independently selected from hydrogen, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, a halogen element, and an alkyl halide.

[0030] The chemical masking agent supply step, the metal precursor supply step, and the thin film formation step can each be carried out at 50 to 700°C.

[0031] The above reaction substances may be one or more of ammonia (NH3), hydrazine (N2H4), nitrogen dioxide (NO2), nitrogen (N2), and hydrogen (H2).

[0032] The above metal precursor may be a compound containing a hexavalent metal including Mo.

[0033] According to one embodiment of the present invention, a semiconductor device includes a thin film manufactured using the thin film forming method.

[0034] According to one embodiment of the present invention, a method for manufacturing a semiconductor device includes the thin film forming method.

[0035] According to one embodiment of the present invention, the deposition thickness per cycle can be reduced by using a chemical masking agent, and the uniformity and step coverage of the deposited thin film can be improved.

[0036] In addition, seam formation can be prevented by depositing a bottom-up filing thin film.

[0037] FIG. 1 is a flowchart schematically illustrating a thin film formation method according to an embodiment of the present invention.

[0038] FIG. 2 is a graph schematically showing the supply cycle according to an embodiment of the present invention.

[0039] Figure 3 is a graph showing the GPC and resistivity of molybdenum nitride films according to comparative examples and embodiments 1 to 4 of the present invention.

[0040] Figure 4 is a graph showing the results of H-NMR analysis performed to confirm the interaction between the chemical masking agent and the reaction material of Example 1.

[0041] Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the attached FIGS. 1 to 4. Embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be interpreted as being limited to the embodiments described below. These embodiments are provided to further explain the present invention in detail to those skilled in the art to which the invention pertains. Accordingly, the shape of each element shown in the drawings may be exaggerated to emphasize a clearer explanation.

[0042] FIG. 1 is a flowchart schematically illustrating a thin film formation method according to an embodiment of the present invention, and FIG. 2 is a graph schematically illustrating a supply cycle according to an embodiment of the present invention. A substrate is loaded into the interior of a process chamber, and the following ALD process conditions are adjusted. The ALD process conditions may include the temperature of the substrate or the process chamber, chamber pressure, and gas flow rate, and the temperature is 50 to 700°C.

[0043] The substrate is exposed to a chemical masking agent supplied inside the chamber, and the chemical masking agent is adsorbed onto the surface of the substrate. The chemical masking agent can be represented by the following <Chemical Formula 1>.

[0044] <Chemical Formula 1>

[0045]

[0046] In the above <Chemical Formula 1>, R1 to R4 are each independently selected from hydrogen, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an arylalkyl group having 6 to 12 carbon atoms.

[0047] In this case, in <Chemical Formula 1>, if R1 to R4 are alkyl groups having 1 carbon atom (specifically, methyl groups), the chemical masking agent corresponds to 2,3-dimethyl-2-butene.

[0048] In addition, the chemical masking agent can be represented by the following <Chemical Formula 2>.

[0049] <Chemical Formula 2>

[0050]

[0051] In the above <Chemical Formula 2>, X is a carbon or nictogen element (N, P, As, Sb, Bi), and R1 to R6 are each independently selected from hydrogen having 0 to 1 carbon, an alkyl group having 1 to 8 carbons, a cycloalkyl group having 3 to 6 carbons, an aryl group having 6 to 12 carbons, a halogen element, an alkyl halide, or a cyano group.

[0052] In this case, in <Chemical Formula 2>, where X is carbon, R1 is absent, R2, R4, and R6 are alkyl groups with one carbon atom (specifically, methyl groups), and R3 and R5 are hydrogen, the chemical masking agent corresponds to Mesitylene.

[0053] In addition, in <Chemical Formula 2>, where X is carbon, R1 is absent, R2, R3, R4, R6 are hydrogen, and R5 is an alkyl group with 3 carbon atoms (specifically, propene), the chemical masking agent corresponds to Allyl Benzene.

[0054] In addition, the chemical masking agent can be represented by the following <Chemical Formula 3>.

[0055] <Chemical Formula 3>

[0056]

[0057] In the above <Chemical Formula 3>, R1 is each independently selected from hydrogen, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and an aryl group having 6 to 12 carbon atoms.

[0058] In this case, in <Chemical Formula 3>, when R1 is a carbon-5 alkyl group (specifically, 2-methylbutane), the chemical masking agent corresponds to Tert-amyl alcohol (TAA).

[0059] In addition, the chemical masking agent can be represented by the following <Chemical Formula 4>.

[0060] <Chemical Formula 4>

[0061]

[0062] In the above <Chemical Formula 4>, R1 or R2 is each independently selected from hydrogen, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, a halogen element, and an alkyl halide.

[0063] Afterwards, a purge gas (e.g., an inert gas such as Ar) is supplied into the chamber to remove or purify unadsorbed chemical masking agents or byproducts.

[0064] Subsequently, the substrate is exposed to a metal precursor supplied inside the chamber, and the metal precursor is adsorbed onto the surface of the substrate. The metal precursor may be a compound containing a hexavalent metal including Mo.

[0065] Subsequently, a purge gas (e.g., an inert gas such as Ar) is supplied to the inside of the chamber to remove or purify unadsorbed metal precursors or byproducts.

[0066] Subsequently, the substrate is exposed to a reaction material supplied inside the chamber, and a thin film is formed on the surface of the substrate. The reaction material reacts with the metal precursor layer to form a thin film, and the reaction material may be one or more of ammonia (NH3), hydrazine (N2H4), nitrogen dioxide (NO2), nitrogen (N2), and hydrogen (H2), and a metal nitride film may be formed through the reaction material.

[0067] Subsequently, a purge gas (e.g., an inert gas such as Ar) is supplied to the inside of the chamber to remove unreacted substances or byproducts or to purify the chamber.

[0068] - Comparative example

[0069] A molybdenum nitride film was formed on a silicon substrate through an ALD process, with an ALD process temperature of 550°C and NH3 gas used as the reaction material.

[0070] The process of forming a molybdenum nitride film through the ALD process is as follows, and the process below was carried out as one cycle.

[0071] 1) Using Ar as a carrier gas, the molybdenum precursor MoO2Cl2 (Molybdenum Dichloride Dioxide) is supplied to the reaction chamber at room temperature, and the molybdenum precursor is adsorbed onto the substrate.

[0072] 2) Supply Ar gas into the reaction chamber to remove unadsorbed molybdenum precursors or byproducts

[0073] 3) Supply NH3 gas to the reaction chamber to form a molybdenum nitride film.

[0074] 4) Supply Ar gas into the reaction chamber to remove unreacted materials or byproducts

[0075] The thickness of the molybdenum nitride film obtained through the above process was measured by TEM, and the growth per cycle (GPC), which is the thickness of the molybdenum nitride film obtained per cycle of the ALD process, was confirmed to be 1.03 Å, and the resistivity was 260 μΩ cm @ 103 Å.

[0076] - Example 1

[0077] A molybdenum nitride film was formed on a silicon substrate using 2,3-dimethyl-2-butene as the chemical masking agent described earlier. The molybdenum nitride film was formed via an ALD process, with an ALD process temperature of 550°C and NH3 gas used as the reaction agent.

[0078] The process of forming a molybdenum nitride film through the ALD process is as follows, and the process below was carried out as one cycle (refer to Figures 1 and 2).

[0079] 1) Supply a chemical masking agent into the reaction chamber to adsorb the chemical masking agent onto the substrate

[0080] 2) Supply Ar gas into the reaction chamber to remove unadsorbed chemical masking agents or byproducts

[0081] 3) Using Ar as a carrier gas, supply the molybdenum precursor MoO2Cl2 (Molybdenum Dichloride Dioxide) to the reaction chamber at room temperature and adsorb the molybdenum precursor onto the substrate.

[0082] 4) Supply Ar gas into the reaction chamber to remove unadsorbed molybdenum precursors or byproducts

[0083] 5) Supply NH3 gas to the reaction chamber to form a molybdenum nitride film.

[0084] 6) Supply Ar gas into the reaction chamber to remove unreacted materials or byproducts

[0085] As a result of using 2,3-dimethyl-2-butene as a chemical masking agent, the growth per cycle (GPC) was reduced to 0.59 Å (GPC reduction rate: 42.7%) compared to the comparative example, and the resistivity was confirmed to be 333 μΩ cm @ 59.3 Å.

[0086] - Example 2

[0087] A molybdenum nitride film was formed in the same manner as in Example 1, except that the chemical masking agent was changed to Mesitylene.

[0088] As a result of using Mesitylene as a chemical masking agent, the growth per cycle (GPC) was reduced to 0.55 Å (GPC reduction rate: 46.6%) compared to the comparative example, and the resistivity was confirmed to be 418 μΩ cm @ 54.9 Å.

[0089] - Example 3

[0090] A molybdenum nitride film was formed in the same manner as in Example 1, except that the chemical masking agent was changed to Tert-amyl alcohol (TAA).

[0091] As a result of using TAA as a chemical masking agent, the growth per cycle (GPC) was reduced to 0.62 Å (GPC reduction rate: 39.8%) compared to the comparative example, and the resistivity was confirmed to be 414 μΩ cm @ 61.5 Å.

[0092] - Example 4

[0093] A molybdenum nitride film was formed in the same manner as in Example 1, except that the chemical masking agent was changed to Allyl Benzene.

[0094] As a result of using Allyl Benzene as a chemical masking agent, the growth per cycle (GPC) was reduced to 0.02 Å (GPC reduction rate: 98.3%) compared to the comparative example, and the resistivity was confirmed to be 880 μΩ cm @ 17.1 Å.

[0095] FIG. 3 is a graph showing the GPC and resistivity of molybdenum nitride films according to comparative examples and Examples 1 to 4 of the present invention. In the case of Examples 1 to 3, the GPC was reduced by about 40-50% compared to the comparative example, and the uniformity and step coverage of the deposited molybdenum nitride film are also expected to be improved compared to the comparative example.

[0096] In addition, the resistivity appears to be at an equivalent level compared to the comparative example, and it is expected that the chemical masking agent will be removed without remaining on the thin film.

[0097] In the case of Example 4, GPC was reduced by about 98% compared to the comparative example, so almost no molybdenum nitride film was formed, which appears to be because the chemical masking agent effectively suppressed molybdenum deposition.

[0098] In addition, chemical masking agents are expected to behave similarly to molybdenum precursors and are adsorbed in large quantities on the upper part of the pattern. When such chemical masking agents are used, the formation of a molybdenum nitride film on the upper part of the pattern is suppressed, and a molybdenum nitride film is formed on the lower part, making it possible to deposit a bottom-up filling film.

[0099] Figure 4 is a graph showing the results of H-NMR analysis performed to confirm the interaction between the chemical masking agent of Example 1 and the reaction material. The reaction material was NH4Cl, which has a structure similar to NH3 (gas phase), and the chemical masking agent of Example 1 were mixed in a 1:1 mole ratio, and H-NMR analysis was performed. Dimethyl Sulfoxide-d6 (DMSO-d6) was used as the NMR solvent.

[0100] As a result of NMR analysis of the solution mixed with NH4Cl and the chemical masking agent of Example 1, the NH4+ peak underwent a chemical shift of 0.052 from 7.177 to 7.229 after mixing with the chemical masking agent, confirming the interaction between NH4Cl and the chemical masking agent. This phenomenon indirectly confirmed the interaction between the chemical masking agent and the reactant NH3, and furthermore, it appears that the chemical masking agent material can be removed by NH3 due to this interaction.

[0101] Although the present invention has been described in detail through embodiments above, other forms of embodiments are also possible. Therefore, the technical concept and scope of the claims described below are not limited to the embodiments.

[0102] The present invention can be applied to various types of semiconductor manufacturing methods.

Claims

1. A chemical masking agent supply step of supplying a chemical masking agent into the interior of a chamber on which a substrate is placed, thereby adsorbing the chemical masking agent onto the substrate; A step of purging the interior of the above chamber; A metal precursor supply step of supplying a metal precursor, which is a compound containing a hexavalent metal including Mo, into the interior of the chamber and adsorbing the metal precursor onto the substrate; A step of purging the interior of the above chamber; and A method for forming a thin film using a chemical masking agent, comprising a thin film forming step of supplying a reaction material into the interior of the chamber to react with the adsorbed metal precursor and form a thin film.

2. In Paragraph 1, A method for forming a thin film using a chemical masking agent represented by the following <Chemical Formula 1>. <Chemical Formula 1> In the above <Chemical Formula 1>, R1 to R4 are each independently selected from hydrogen, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an arylalkyl group having 6 to 12 carbon atoms.

3. In Paragraph 1, A method for forming a thin film using a chemical masking agent, wherein the chemical masking agent is represented by the following <Chemical Formula 2>. <Chemical Formula 2> In the above <Chemical Formula 2>, X is a carbon or nictogen element (N, P, As, Sb, Bi), and R1 to R6 are each independently selected from hydrogen having 0 to 1 carbon, an alkyl group having 1 to 8 carbons, a cycloalkyl group having 3 to 6 carbons, an aryl group having 6 to 12 carbons, a halogen element, an alkyl halide, or a cyano group.

4. In Paragraph 1, A method for forming a thin film using a chemical masking agent, wherein the chemical masking agent is represented by the following <Chemical Formula 3>. <Chemical Formula 3> In the above <Chemical Formula 3>, R1 is selected from hydrogen, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and an aryl group having 6 to 12 carbon atoms.

5. In Paragraph 1, A method for forming a thin film using a chemical masking agent, wherein the chemical masking agent is represented by the following <Chemical Formula 4>. <Chemical Formula 4> In the above <Chemical Formula 4>, R1 or R2 is each independently selected from hydrogen, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, a halogen element, and an alkyl halide.

6. In Paragraph 1, A method for forming a thin film using a chemical masking agent, wherein the chemical masking agent supply step, the metal precursor supply step, and the thin film formation step are each carried out at 50 to 700°C.

7. In Paragraph 1, A method for forming a thin film using a chemical masking agent, wherein the above-mentioned reaction material is one or more of ammonia (NH3), hydrazine (N2H4), nitrogen dioxide (NO2), nitrogen (N2), and hydrogen (H2).

8. A semiconductor device comprising a thin film manufactured using a thin film forming method described in any one of claims 1 to 7.

9. A method for manufacturing a semiconductor device comprising a thin film forming method described in any one of claims 1 to 7.

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