Ultrathin film, ultrathin film forming method, semiconductor substrate prepared through ultrathin film and semiconductor device

Abstract

The present invention relates to an ultrathin film, an ultrathin film forming method, a semiconductor substrate comprising the same, and a semiconductor device comprising the same, and provides an ultrathin film, an ultrathin film forming method, an ultrathin film forming agent, a semiconductor substrate comprising the same, and a semiconductor device comprising the same. The present invention relates to a method for manufacturing a thin film, and also modifies the thin film to improve the initial reactivity of deposition, so that even if the thin film is formed at an extremely thin thickness, not only can further reduce current leakage or further improve current characteristics, but also can achieve improved quality by densifying and removing impurities, etc.

Description

Technical Field

[0001] This invention relates to an ultrathin film, an ultrathin film formation method, a semiconductor substrate and semiconductor device prepared by the ultrathin film, and more specifically, to an ultrathin film, an ultrathin film formation method, a forming agent, a semiconductor substrate and semiconductor device including the ultrathin film, wherein the ultrathin film is not only made of a barrier material and / or a high dielectric material, but is also modified to improve the initial reactivity of deposition, thereby further reducing current leakage or further improving current characteristics even when formed at an extremely thin thickness. In addition, improved quality can be achieved through densification and impurity removal. Background Technology

[0002] With the increasing demands for improved performance and higher integration of semiconductor devices, various problems have arisen, such as the increase in resistivity as the thickness of the deposited material decreases, and pinholes generated by post-processing.

[0003] In particular, it is difficult to form a uniform film for barrier metal electrodes with a thickness of less than 1.5 nm, thus forming a thick film.

[0004] Therefore, there is a need to develop ultrathin film formation technology that can effectively form ultrathin films regardless of the barrier material or high dielectric material, and can provide dense films that do not have pinholes during etching evaluation.

[0005] Existing technical documents Patent documents Korean Patent Publication No. 2016-0022792. Summary of the Invention

[0006] The problem the invention aims to solve In order to solve the problems of the prior art as described above, the present invention aims to provide an ultrathin film, an ultrathin film forming method, a forming agent, a semiconductor substrate including the ultrathin film, and a semiconductor device, wherein the ultrathin film is not only made of a barrier material and / or a high dielectric material, but is also modified to improve the initial reactivity of deposition, so that even when formed at an extremely thin thickness, current leakage can be further reduced or current characteristics can be further improved. In addition, improved quality can be achieved through densification and impurity removal.

[0007] The above-mentioned and other objectives of the present invention can be achieved by the present invention as will be described below.

[0008] means for solving problems To achieve the aforementioned objective, the present invention is characterized in that: I) it comprises a thin film formed on a substrate using one or more materials selected from barrier materials and high dielectric materials, wherein the thickness of the thin film, as measured by TEM, is less than 10 nm, and the square root average surface roughness of the thin film is less than 0.3 nm.

[0009] In addition, the present invention provides an ultrathin film, characterized in that, II) it comprises a thin film formed on a substrate using one or more materials selected from barrier materials and high dielectric materials, the thickness of which is less than 5 nm as measured by TEM, and the GPC is increased by more than 30% by using a modified gas.

[0010] III), according to I) to II), after the film is immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes, the surface roughness measured by scanning probe microscopy (atomic force microscopy (AFM)) can be below 0.3 nm.

[0011] IV), according to I) to III), the thin film may be selected from one or more of titanium nitride film, tantalum nitride film, ruthenium film, aluminum oxide film, calcium oxide film, yttrium oxide film, strontium oxide film, zirconium oxide film, hafnium oxide film, tantalum oxide film, lanthanum oxide film, barium oxide film and titanium oxide film.

[0012] According to (V), and according to (I) to (IV), the thin film can be two or more multi-element oxide films having a perovskite structure or a pyrochlore structure.

[0013] According to I) to V), after the film is immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes, the maximum etching height of the film from the top to the bottom (the side closest to the substrate), as measured by scanning probe microscopy (atomic force microscopy, AFM), can be less than 50% by etching evaluation.

[0014] According to I) to VI), after the film is immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes, the maximum etching height of the film from the top to the bottom (the side closest to the substrate), as measured by scanning probe microscopy (atomic force microscopy, AFM), can be less than 1.5 nm by etching evaluation.

[0015] In addition, the present invention provides an ultrathin film formation method, characterized in that, VIII) the ultrathin film formation method includes: an adsorption step, in which an adsorbent material is formed on a substrate by spraying a source gas composed of one or more materials selected from barrier materials and high dielectric materials; a modification step, in which the adsorbent material formed on the substrate is modified by spraying a modification gas that reacts with the source gas; and a deposition step, in which a thin film composed of one or more materials selected from barrier materials and high dielectric materials is deposited on the substrate by spraying a reaction gas that reacts with the modification gas; when the adsorption step, modification step and deposition step are combined into one cycle, the following conditions are simultaneously met: the thickness of the thin film formed after repeating 10 cycles is less than 10 angstroms, and the thickness of the thin film formed after repeating 20 cycles is less than 20 angstroms.

[0016] In addition, the present invention provides an ultrathin film formation method, characterized in that, (IX) the ultrathin film formation method includes: a modification step, wherein a modification gas is sprayed onto the substrate surface and the surface is modified by adsorption reaction with a source gas on the substrate; an adsorption step, wherein an adsorbent material is formed on the substrate by spraying a source gas composed of one or more materials selected from barrier materials and high dielectric materials; and a deposition step, wherein a thin film composed of one or more materials selected from barrier materials and high dielectric materials is deposited on the substrate by spraying a reaction gas that reacts with the source gas; when the modification step, adsorption step and deposition step are performed as a cycle, the following conditions are simultaneously met: the thickness of the thin film formed after 10 cycles is less than 10 angstroms, and the thickness of the thin film formed after 20 cycles is less than 20 angstroms.

[0017] X), according to VIII) to IX), as the source gas in the adsorption step, may be one or more selected from titanium (Ti), tantalum (Ta), aluminum (Al), ruthenium (Ru), niobium (Nb), bismuth (Bi), calcium (Ca), yttrium (Y), strontium (Sr), zirconium (Zr), hafnium (Hf), lanthanum (La) and barium (Ba).

[0018] According to (VIII) to (X), in order to reduce the central metal atom at a low process temperature below 400 degrees, the source gas can be a compound with a bond dissociation energy of less than 350 kJ / mol between the central metal atom and the ligand, wherein the bond dissociation energy is calculated using the Gaussian 16 program (based on the basis set of DFT-D3 / B3LYP (central metal, iodine: LanL2DZ, C, N, O, H, X: 6-31+G(dp))).

[0019] According to XII), the modification step described in VIII) to XI) can be carried out by spraying a halogen gas containing iodine with a weight-average molecular weight of 127 g / mol to 250 g / mol onto the substrate as a modifying gas.

[0020] According to (XIII), and according to (VIII) to (XII), the modified gas may include materials having direct bonds between hydrogen (H) and iodine, materials having direct bonds between carbon (C) and iodine, or materials having direct bonds between halogens (F, Cl, Br) and iodine.

[0021] XIV), according to VIII) to XIII), the material having direct bonds of hydrogen (H) and iodine can be a material whose overall binding energy of the compound is in the range of 305 kJ / mol to 325 kJ / mol, calculated using the Gaussian 16 procedure (DFT-D3 / B3LYP basis set (iodine: LanL2DZ, carbon and hydrogen elements: 6-31+G(dp))).

[0022] XV), according to VIII) to XIV), the material having direct bonds of carbon (C) and iodine can be a material with an overall binding energy of 165 kJ / mol to 242 kJ / mol and exhibiting a tertiary structure, calculated using the Gaussian 16 procedure (DFT-D3 / B3LYP basis set (iodine: LanL2DZ, carbon and hydrogen elements: 6-31+G(dp))).

[0023] XVI), according to VIII) to XV), the material having direct bonds of halogen elements (F, Cl, Br) and iodine can be a material whose overall binding energy of the compound is in the range of 50 kJ / mol to 160 kJ / mol, calculated using the Gaussian 16 procedure (DFT-D3 / B3LYP basis set (iodine: LanL2DZ, carbon and hydrogen elements: 6-31+G(dp))).

[0024] According to XVII), the deposition step can be performed by spraying ozone (O3), oxygen (O2), nitrogen (N2) or ammonia (NH3) as a reactive gas onto the substrate.

[0025] According to (XVIII) to (XVII), the ultrathin film formation method may include: a first purging step, after performing the adsorption step, spraying a purging gas onto the substrate; a second purging step, after performing the modification step, spraying a purging gas onto the substrate; and a third purging step, after performing the deposition step, spraying a purging gas onto the substrate.

[0026] In addition, the present invention provides a method for forming ultrathin films, characterized in that, in order to modify the surface or adsorbed source material, a compound with a bond dissociation energy of less than 350 kJ / mol between the central metal atom and the ligand is used, wherein the bond dissociation energy is calculated using the Gaussian 16 program (the basis set of DFT-D3 / B3LYP (central metal, iodine: LanL2DZ, C, N, O, H, X: 6-31+G(dp)).

[0027] In addition, the present invention provides a semiconductor substrate, characterized in that the semiconductor substrate (XX) includes the aforementioned ultrathin film.

[0028] According to XX), the ultrathin film can be a multilayer structure with two or three layers.

[0029] In addition, the present invention provides a semiconductor device, characterized in that, XXII) the semiconductor device includes the aforementioned semiconductor substrate.

[0030] Invention Effects According to the present invention, it has the effects of providing an ultrathin film, an ultrathin film forming method, a forming agent, a semiconductor substrate containing the ultrathin film, and a semiconductor device, wherein the ultrathin film is not only made of a barrier material and / or a high dielectric material, but is also modified to improve the initial reactivity of deposition, so that even if it is formed with an extremely thin thickness, current leakage can be further reduced or current characteristics can be further improved. In addition, improved quality can be achieved by densification and removal of impurities.

[0031] Furthermore, by improving impurities and film quality, it can provide a high-quality ultrathin film formation method and a semiconductor substrate prepared by the method. Attached Figure Description

[0032] Figures 1 to 2 This is a graph comparing the film formation thickness of embodiments of the present invention with that of comparative examples of the prior art.

[0033] Figure 3 The etching evaluation results between the embodiments of the present invention and the comparative examples of the prior art are shown in scanning electron microscope (SEM) images after immersion in hydrofluoric acid (HF, 1% dilution) for 5 minutes.

[0034] Figure 4 This is an etching evaluation result between an embodiment of the present invention and a comparative example of the prior art, which is a scanning probe microscope (atomic force microscope (AFM) image showing the etching evaluation results of immersion in hydrofluoric acid (HF, 1% dilution) for various time periods. Detailed Implementation

[0035] The ultrathin film and the method for forming the ultrathin film in this invention will be described in detail below.

[0036] In this invention, the term "ultra-thin film" refers to a film made of a barrier material or a high dielectric material whose thickness simultaneously meets the following conditions: less than 10 angstroms / 10 cycles and less than 20 angstroms / 10 cycles.

[0037] The thickness of the film can be measured using TEM, but is not limited to this method.

[0038] In this invention, unless otherwise stated, the term "modified gas" refers to an ultrathin film forming material.

[0039] In this invention, unless otherwise stated, the term "modification" means that materials other than barrier materials or high dielectric materials and said barrier materials and / or high dielectric materials have positive interactions on the reaction surface.

[0040] Positive interactions can lead to improvements in film quality, such as reduced resistivity, increased density, reduced impurities, and film densification, but are not limited to these.

[0041] In this invention, unless otherwise mentioned, % refers to weight.

[0042] The inventors have confirmed that by using modified materials that are not only made of barrier materials and / or high dielectric materials but also improve the initial reactivity of deposition, even when formed at extremely thin thicknesses, it is possible to further reduce current leakage or further improve current characteristics. This invention is achieved by forming ultrathin films of improved quality through densification and impurity removal.

[0043] The ultrathin film of the present invention may include a thin film formed on a substrate using one or more materials selected from barrier materials and high dielectric materials.

[0044] As an example, the barrier material and / or high dielectric material may be titanium nitride film, tantalum nitride film, ruthenium film, aluminum oxide film, calcium oxide film, yttrium oxide film, strontium oxide film, zirconium oxide film, hafnium oxide film, tantalum oxide film, lanthanum oxide film, barium oxide and titanium oxide film, etc.

[0045] The ultrathin film can be two or more multi-element oxide films with perovskite or pyrochlore structures.

[0046] The ultrathin film of the present invention is characterized in that it comprises a thin film formed on a substrate using one or more materials selected from barrier materials and high dielectric materials, wherein the thickness of the thin film measured by TEM is less than 10 nm and the square root average surface roughness of the thin film is less than 0.3 nm. Under these conditions, a flat ultrathin film can be provided, while exhibiting significant initial deposition reactivity.

[0047] Furthermore, the present invention is characterized by including a thin film formed on a substrate using one or more materials selected from barrier materials and high dielectric materials, with a thickness of 5 nm or less as measured by TEM, and GPC being improved by more than 30% by using a modified gas. In this case, the effect of providing a flat ultrathin film can be significant.

[0048] The thin film may be selected from one or more of the following: titanium nitride film, tantalum nitride film, aluminum oxide film, calcium oxide film, yttrium oxide film, strontium oxide film, zirconium oxide film, hafnium oxide film, tantalum oxide film, lanthanum oxide film, barium oxide film, or titanium oxide film.

[0049] The film is characterized in that, after being immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes, the surface roughness measured by AFM is less than 0.3 nm. In this case, it belongs to ultrathin film and can also provide film compactness.

[0050] The film is characterized in that, after immersion in hydrofluoric acid (HF, 1% dilution) for 5 minutes, the maximum etching height of the film from the top to the bottom (the side closest to the substrate), as measured by a scanning probe microscope (atomic force microscope, AFM), is, for example, less than 50%, and as a specific example, less than 20%, preferably 0% or close to 0%. In this case, it is considered an ultrathin film and also provides film density, which is therefore preferred.

[0051] The film is characterized in that, after immersion in hydrofluoric acid (HF, 1% dilution) for 5 minutes, the maximum etching height of the film from the top to the bottom (the side closest to the substrate), as measured by a scanning probe microscope (atomic force microscope, AFM), is, for example, less than 2 nm, and as a specific example, less than 1 nm, preferably 0 nm or close to 0 nm. In this case, it is an ultrathin film and can also provide film density, so it is preferred.

[0052] The aforementioned ultrathin films can be prepared by including an adsorption step, a modification step, and a deposition step.

[0053] In the adsorption step, an adsorption material is formed on the substrate by spraying a source gas composed of one or more materials selected from barrier materials and high dielectric materials.

[0054] The adsorption step can be performed by spraying the source gas onto the substrate through a first gas flow path provided by the injection unit.

[0055] The source gas may include at least one of titanium (Ti), tantalum (Ta), aluminum (Al), ruthenium (Ru), niobium (Nb), bismuth (Bi), calcium (Ca), yttrium (Y), strontium (Sr), zirconium (Zr), hafnium (Hf), lanthanum (La), and barium (Ba).

[0056] The titanium (Ti) and tantalum (Ta) correspond to barrier materials or high dielectric materials, and the aluminum (Al), calcium (Ca), yttrium (Y), strontium (Sr), zirconium (Zr), hafnium (Hf), lanthanum (La), and barium (Ba) are all high dielectric materials.

[0057] The source gas may be a gas made from a precursor material having ligands, with at least one of titanium (Ti), tantalum (Ta), aluminum (Al), ruthenium (Ru), niobium (Nb), bismuth (Bi), calcium (Ca), yttrium (Y), strontium (Sr), zirconium (Zr), hafnium (Hf), lanthanum (La), and barium (Ba) as the central metal atom.

[0058] As an example, for the aforementioned precursor material, in order to reduce the central metal atom at a low process temperature below 400°C, the ligand can be selected to have a bond dissociation energy between the central metal atom and the ligand of less than 350 kJ / mol. The bond dissociation energy is calculated using the Gaussian 16 program (based on the basis set of DFT-D3 / B3LYP (central metal, iodine: LanL2DZ, C, N, O, H, X: 6-31+G(dp))).

[0059] That is, the ligand can be an element including halogens (F, Cl or Br), C, H, N, O, S, P, but is not limited thereto.

[0060] As an example, the precursor material can be a titanium precursor or a tantalum precursor.

[0061] In a preferred embodiment, the titanium precursor may be titanium halide.

[0062] As an example, the titanium halide may be selected from at least one of the group consisting of TiF4, TiCl4, TiBr4 and TiI4. For example, TiCl4 is preferred for economic reasons, but it is not limited thereto.

[0063] In a preferred embodiment, the tantalum precursor may be tantalum halide or alkyliminotris(diethylamino)tantalum (R1N=Ta(NEt2)3). The alkyl group may be a straight chain or a branched chain having 1 to 5 carbon atoms.

[0064] As an example, the tantalum halide may be selected from at least one of the group consisting of TaF5, TaCl5, TaBr5, TaI5 and tert-butyliminotris(diethylamino)tantalum (t-BuN=Ta(NEt2)3, TBTDET), for example, TaCl5 is preferred for economic reasons, but is not limited thereto.

[0065] The titanium halide or tantalum halide has excellent thermal stability, does not decompose at room temperature, and has very high vapor pressure characteristics. Therefore, it can be used as a precursor for atomic layer deposition (ALD) or chemical vapor deposition (CVD) to effectively deposit thin films.

[0066] As an example, the precursor material can be mixed with a nonpolar solvent and used, in which case it has the advantage of being able to easily adjust the viscosity or vapor pressure of the precursor material.

[0067] As another example, the precursor material may have a structure in which at least one of titanium (Ti), tantalum (Ta), aluminum (Al), ruthenium (Ru), niobium (Nb), bismuth (Bi), calcium (Ca), yttrium (Y), strontium (Sr), zirconium (Zr), hafnium (Hf), lanthanum (La) and barium (Ba) is used as the central metal atom and is bonded with ligands (L1, L2, L3, L4, L5, L6, etc.).

[0068] The ligands (L1, L2, L3, L4, L5, L6, etc.) can be iodine-free ligands.

[0069] As an example, L1, L2, L3, L4, L5, and L6 can be ligands composed of C, N, O, H, F, Cl, Br, etc.

[0070] As a specific example, the precursor material is a molecule with Mo, W, Ru, Cu, Rh, Pb, Cd, Sn, Bi, In, Ti, Ta, Ni, Mo, Nb, Zr, V, and Ga as the central metal atom (M) and having one or more ligands composed of C, N, O, H, F, Cl, and Br. When the precursor has a vapor pressure of 0.01 mTorr to 100 Torr at a temperature of 25°C, the effect of using the modified gas can be maximized.

[0071] As another specific example, the precursor material, as a molecule having at least one of titanium (Ti), tantalum (Ta), aluminum (Al), ruthenium (Ru), niobium (Nb), bismuth (Bi), calcium (Ca), yttrium (Y), strontium (Sr), zirconium (Zr), hafnium (Hf), lanthanum (La), and barium (Ba) as the central metal atom and having one or more ligands composed of C, N, O, H, F, Cl, and Br, can be a compound whose bond dissociation energy between the central metal atom and the ligand is less than 350 kJ / mol, calculated using the Gaussian 16 program (based on the DFT-D3 / B3LYP basis set (central metal, iodine: LanL2DZ, C, N, O, H, X: 6-31+G(dp))).

[0072] As an example, when the central metal is divalent, L1 and L2 can be attached to the central metal as ligands. When the central metal is hexavalent, L1, L2, L3, L4, L5, and L6 can be attached to the central metal, and the ligands corresponding to L1 to L6 can be the same or different from each other.

[0073] As an example, L1, L2, L3, L4, L5, and L6 can be the same as or different from each other as -H or -R, wherein -R can be a C1-C10 alkyl, C1-C10 olefin, or C1-C10 alkane, and can be a straight-chain or cyclic structure, and the number of n in L in L1, L2, L3, and L4 can be 2 to 6 depending on the oxidation value of the central metal.

[0074] As an example, when the central metal is divalent, L1 and L2 can be attached to the central metal as ligands. When the central metal is hexavalent, L1, L2, L3, L4, L5, and L6 can be attached to the central metal, and the ligands corresponding to L1 to L6 can be the same or different from each other.

[0075] As specific examples, L1, L2, L3, L4, L5, and L6 may be the same as or different from each other as -H, -OR, or -NR2, wherein -R may be H, a C1-C10 alkyl group, a C1-C10 alkene, a C1-C10 alkane, iPr, or TBu, in which case it has a reaction energy suitable for substitution with the reaction gas described later.

[0076] As a specific example, L1, L2, L3, L4, L5, and L6 can be the same as or different from each other as -H or -X, where -X can be F, Cl, or Br, and in this case, have a reaction energy suitable for being replaced by the reaction gas described later.

[0077] As a specific example, L1, L2, L3, L4, L5, and L6 may be the same as or different from each other as -H or -R, wherein -R may be a C1-C10 alkyl, C1-C10 olefin, or C1-C10 alkane, and may have a straight-chain or cyclic structure, in which case it has a reaction energy suitable for being replaced by the reaction gas described later.

[0078] As specific examples, L1, L2, L3, L4, L5, and L6 may be the same as or different from each other as -H, -OR, or -NR2, wherein -R may be H, C1-C10 alkyl, C1-C10 olefin, C1-C10 alkane, iPr, or tBu, in which case it has a reaction energy suitable for being substituted by the reaction gas described later.

[0079] As a specific example, L1, L2, L3, L4, L5, and L6 can be the same as or different from each other as -H or -X, where -X can be F, Cl, or Br, and in this case, have a reaction energy suitable for being replaced by the reaction gas described later.

[0080] The bond dissociation energy of the precursor material is an important factor in the deposition of the precursor material together with the modified gas. The computer simulation program used to calculate the bond dissociation energy is Gaussian 16, and the computer simulation method used is DFT-D3 / B3LYP. In terms of the basis set, iodine and the central metal (e.g., molybdenum) are LanL2DZ, and the other elements are 6-31+G(dp).

[0081] The reactivity energy of the precursor material and the reactant gas is also calculated using the same method. In this case, the transition state method is DFT / TS-Berny, and the intrinsic reaction coordinate is 40 pts.

[0082] The precursor material can be transferred into the chamber via VFC, DLI, or LDS.

[0083] The time (seconds) for each cycle of the precursor material to be sprayed (fed) onto the substrate is preferably 0.01 seconds to 10 seconds, more preferably 0.02 seconds to 8 seconds, even more preferably 0.04 seconds to 6 seconds, and most preferably 0.05 seconds to 4 seconds. Within this range, it has the advantages of improved initial film formation rate, excellent step coverage, and good economy.

[0084] The feeding time is based on a flow rate of 0.1 mg / cycle to 8000 mg / cycle in a chamber volume of 15L to 20L, and more specifically, on a flow rate of 10 mg / cycle to 5000 mg / cycle in a chamber volume of 18L.

[0085] The ultrathin film may contain the aforementioned film composition alone or as a selective area, but is not limited thereto, and may also contain SiH and SiOH, etc.

[0086] As an example, the ultrathin film can be used in semiconductor devices as a wiring metal film or a wiring metal diffusion prevention film.

[0087] The resistivity of the ultrathin film can range from 5 μΩ·cm to 1000 μΩ·cm.

[0088] In the adsorption step, when a mixed gas comprising two or more materials is injected onto the substrate, a first source gas comprising the first material and a second source gas comprising the second material can be mixed in a buffer tank, which is separated from the injection section, to generate a mixed gas. This mixed gas is then supplied to the injection section and injected onto the substrate. Alternatively, the first and second source gases can be injected onto the substrate sequentially. This allows for the preparation of a thin film with improved step coverage and enhanced uniformity.

[0089] As an example, the modification step may occur on the entire substrate or part of the substrate on which the ultrathin film to be provided is formed.

[0090] The modification step can be carried out using a modifying gas that reacts with the source gas. For example, the adsorbent material formed on the substrate can be modified by spraying a modifying gas that reacts with the source gas.

[0091] As an example, the modified gas can be a halogen gas containing iodine with a weight-average molecular weight of 127 g / mol to 250 g / mol, which in this case is an ultrathin film and can also provide film compactness.

[0092] As a specific example, the modified gas may be one or more of the following: materials having direct bonds between hydrogen (H) and iodine, materials having direct bonds between carbon (C) and iodine, or materials having direct bonds between halogens (F, Cl, Br) and iodine.

[0093] As an example, the material having direct bonds between hydrogen (H) and iodine can be a material whose overall binding energy, calculated using the Gaussian 16 procedure (DFT-D3 / B3LYP basis set (iodine: LanL2DZ, carbon and hydrogen: 6-31+G(dp))), is in the range of 305 kJ / mol to 325 kJ / mol. In this case, it belongs to ultrathin films and can also provide film compactness.

[0094] The material having direct bonds between carbon (C) and iodine can be a material exhibiting a tertiary structure with an overall binding energy of 165 kJ / mol to 242 kJ / mol calculated using the Gaussian 16 procedure (DFT-D3 / B3LYP basis set (iodine: LanL2DZ, carbon and hydrogen: 6-31+G(dp))). In this case, it belongs to ultrathin films and can also provide film compactness.

[0095] The material having direct bonds between halogens (F, Cl, Br) and iodine can be a material whose overall binding energy, calculated using the Gaussian 16 procedure (DFT-D3 / B3LYP basis set (iodine: LanL2DZ, carbon and hydrogen: 6-31+G(dp))), is in the range of 50 kJ / mol to 160 kJ / mol. In this case, it belongs to ultrathin films and can also provide film compactness.

[0096] In the modified gas, the overall binding energy of the compound having direct bonds of hydrogen (H) and iodine, calculated using the Gaussian 16 program (DFT-D3 / B3LYP basis set (iodine: LanL2DZ, carbon and hydrogen elements: 6-31+G(dp)) can be between 305 kJ / mol and 325 kJ / mol. In this case, the content of membrane impurities caused by ligands such as carbon can be reduced, and low-resistivity thin films can be effectively provided.

[0097] The modified gas can be selected from one or more compounds represented by the following chemical formulas 1-1 to 1-12, in which case it belongs to an ultrathin film and can also provide film compactness.

[0098] [Chemical Formulas 1-1 to 1-12]

[0099] As an example, the modified gas is a single substance of hydrogen iodide from 3N to 15N, a gas mixture (1% to 99% by weight of hydrogen iodide from 3N to 15N and the balance of an inactive gas to make the total amount 100% by weight), or an aqueous solution mixture (0.5% to 70% by weight of hydrogen iodide from 3N to 15N and the balance of water to make the total amount 100% by weight). The inactive gas can be nitrogen, helium, or argon with a purity of 4N to 9N. In this case, impurities can be reduced by carrying out a reduction reaction, and low-resistivity thin films or metal nitride films can be effectively formed.

[0100] Preferably, the modified gas is a single substance of 5N to 6N hydrogen iodide, a gas mixture (1% to 99% by weight of 5N to 6N hydrogen iodide and the balance of an inactive gas to make the total 100% by weight), or an aqueous solution mixture (0.5% to 70% by weight of 5N to 6N hydrogen iodide and the balance of water to make the total 100% by weight). The inactive gas can be nitrogen, helium, or argon with a purity of 4N to 9N. In this case, when forming an ultrathin film, by suppressing side reactions and adjusting the initial film formation rate, the process byproducts in the ultrathin film can be reduced to reduce corrosion or degradation. This not only improves the film quality (such as enhancing film crystallinity) but also significantly improves the film thickness uniformity, even when forming a film on a highly integrated or complex substrate.

[0101] In this case, at a lower process temperature where the precursor is not thermally decomposed, by providing sufficient reduction reaction effect to the precursor material adsorbed on the substrate, a thin film can be formed on a highly integrated or complex substrate. This has the following advantages: significantly improved film thickness uniformity; prevention of adsorption of process byproducts in addition to the precursor; effective protection of the substrate surface; and effective removal of process byproducts, not only reducing the reaction rate.

[0102] Preferably, the modified gas can be a compound with a purity of 99.9% or higher, a purity of 99.95% or higher, or a purity of 99.99% or higher. For reference, if a compound with a purity of less than 99% is used, impurities may remain in the film or react with precursors or reactants. Therefore, materials with a purity of 99% or higher should be used whenever possible.

[0103] The modified gas can be transferred into the chamber via VFC, DLI, or LDS.

[0104] The ratio of the precursor material to the amount of modified gas introduced into the chamber (mg / cycle) can be from 1:1 to 1:20. In this case, it is an ultrathin film and can also provide film density.

[0105] The time (seconds) for each cycle of the modified gas to be injected (fed) onto the substrate is preferably 0.01 seconds to 10 seconds, more preferably 0.02 seconds to 8 seconds, even more preferably 0.04 seconds to 6 seconds, and most preferably 0.05 seconds to 4 seconds. Within this range, it has the advantages of improved initial film formation rate, excellent step coverage, and good economy.

[0106] The feeding time is based on a flow rate of 0.1 mg / cycle to 8000 mg / cycle in a chamber volume of 15L to 20L, and more specifically, on a flow rate of 10 mg / cycle to 5000 mg / cycle in a chamber volume of 18L.

[0107] The halogen compound provided as the modifying gas can be contained in the film formed by the deposition step described later at a concentration of less than 100 ppm. If excessive halogen residue remains, for example at temperatures of 200°C to 300°C, chlorides (such as NH4Cl) will be generated and remain in the film when the nitriding agent described later is used, which is therefore not preferred.

[0108] The thin film can be used for applications such as wiring metal films or low-resistance metal films, and is not limited thereto.

[0109] In particular, while forming a relatively sparse film, the initial film formation rate is significantly reduced, thus ensuring uniformity even for substrates with complex structures. It can be deposited to a particularly thin thickness and can reduce residual O, Si, metals, and metal oxides as process byproducts. It can even improve the carbon residue that is currently difficult to reduce.

[0110] In the deposition step, a thin film composed of a barrier material and / or a high dielectric material can be deposited on the substrate by spraying a reactive gas that reacts with the source gas.

[0111] The deposition step can be performed by spraying a reactive gas onto the substrate. Through the adsorption step, modification step, and deposition step, a thin film can be formed on the substrate by atomic layer deposition (ALD).

[0112] In the deposition step, ozone (O3), oxygen (O2), nitrogen (N2) or ammonia (NH3) can be sprayed onto the substrate as a reactive gas.

[0113] As an example, based on the volume of the precursor material introduced into the chamber, the amount of the reaction gas can be 10 to 10,000 times, preferably 50 to 50,000 times, more preferably 100 to 10,000 times. Within this range, the redox reaction can be effectively carried out to ensure uniform film formation and prevent film quality deterioration.

[0114] The reactant gas can be transferred into the ALD chamber via VFC, DLI, or LDS, more preferably via VFC.

[0115] Thin films are prepared by depositing barrier materials and / or high dielectric materials through the modification steps, thereby providing the following effects by the ultrathin film formation method according to the present invention.

[0116] First, compared to the comparative example which lacks the aforementioned modification step and is prepared as a thin film made of a barrier material and / or a high-dielectric-rate material, the ultrathin film formation method of the present invention not only produces a thin film made of a barrier material and / or a high-dielectric-rate material, but also modifies it to improve initial deposition reactivity. Therefore, compared to the thin film of the comparative example, even when formed at a thinner thickness, a thin film with further reduced current leakage or further improved current characteristics can be prepared. Thus, the ultrathin film formation method of the present invention can facilitate the fabrication of finer and thinner semiconductor devices.

[0117] Secondly, the ultrathin film formation method according to the present invention, by including the modification step, forms a thin film with a barrier material and / or a high-dielectric material, and simultaneously provides a densification effect and a homogenization effect for improving film density. When a modifying gas is used, materials with low binding strength are induced to have high binding strength, thus thin films with improved quality can be prepared through film densification and impurity removal.

[0118] Third, the ultrathin film formation method according to the present invention, by including the modification step, enables the redox reaction required for the effective deposition of the precursor adsorbed on the substrate to be carried out effectively at a lower process temperature to a degree that prevents the precursor from being thermally decomposed, thereby appropriately increasing the initial film formation rate. This results in significantly improved film uniformity and the provision of a low-resistivity deposited film, even when deposited on highly integrated or complex substrates.

[0119] The ultrathin film formation method may include: a first purging step, a second purging step, and a third purging step.

[0120] The first purging step can be performed after the adsorption step by spraying purging gas onto the substrate.

[0121] The modification step can be performed after the first purging step.

[0122] The second purging step can be performed after the modification step by spraying purging gas onto the substrate.

[0123] The deposition step can be performed after the second purging step.

[0124] The third purging step can be performed after the deposition step by spraying purging gas onto the substrate.

[0125] As an example, the purging gases used in the first purging step, the second purging step, and the third purging step may be inert gases including argon and nitrogen.

[0126] The amount of purge gas is not particularly limited as long as it is sufficient to remove the amount of unadsorbed material (gas). However, as an example, based on the volume of the precursor material introduced into the chamber, it can be 10 to 10,000 times, preferably 50 to 50,000 times, and more preferably 100 to 10,000 times. Within this range, the unadsorbed material (gas) can be sufficiently removed to ensure uniform film formation and prevent film quality deterioration. The amounts of purge gas and precursor material introduced are based on one cycle, and the volume of the precursor material refers to the volume of vaporized precursor material vapor.

[0127] As an example, each purging step is preferably performed at 1,000 sccm to 50,000 sccm (Standard Cubic Centimeter per Minute), more preferably 2,000 sccm to 30,000 sccm, and even more preferably 2,500 sccm to 15,000 sccm. Within this range, the initial film formation rate of each cycle can be appropriately controlled, and deposition is achieved in the form of an atomic mono-layer or in a manner close to that of the atomic layer, thus providing advantages in terms of film quality.

[0128] The entire aforementioned process (adsorption step, first purging step, modification step, second purging step, deposition step, and third purging step) can be repeated in a unit cycle until an ultrathin film of the desired thickness is obtained. Thus, by sequentially introducing the modified gas and precursor material in one cycle to improve film quality, the following advantages are achieved: the generated process byproducts can be effectively removed, thereby reducing resistivity; step coverage is significantly improved and uniformity is enhanced; film quality (electrical properties and density, etc.) is improved; and a low-resistivity film is provided.

[0129] The chamber can be an ALD chamber, a CVD chamber, a PEALD chamber, or a PECVD chamber.

[0130] The substrate loaded in the chamber can be heated to 100°C to 600°C.

[0131] As an example, the reaction temperature of the entire process (adsorption step, first purging step, modification step, second purging step, deposition step and third purging step) can be from 100°C to 600°C.

[0132] This may include a step of vaporizing and injecting the precursor material or modified gas followed by plasma post-treatment, which can improve the initial film formation rate and reduce process byproducts.

[0133] As an example, the substrate loaded in the chamber can be heated to 100°C to 700°C, specifically to 300°C to 600°C. The modified gas or precursor material can be injected onto the substrate in either a heated or unheated state. Depending on the deposition efficiency, it can also be injected in an unheated state, with the heating conditions adjusted during the deposition process. For example, at a temperature of 50°C to 400°C, the injection time on the substrate can be 1 to 20 seconds.

[0134] The ratio of the precursor material to the modified gas in the chamber (mg / cycle) can be from 1:1 to 1:400, more preferably from 1:2 to 1:350, even more preferably from 1:2 to 1:300, and most preferably from 1:2.5 to 1:200. Within this range, the improvement in step coverage and the reduction in process byproducts are significant.

[0135] As an example, in the ultrathin film formation method, when the precursor material and the modified gas are used, the deposition rate increase rate, as expressed by the following mathematical formula 1, can be 25% or more, and as a specific example, it can be 30% or more. In this case, it has the advantages of improving film quality (electrical properties and density, etc.) and providing a low-resistance film.

[0136] [Mathematical Expression 1] deposition rate increase rate = [{(DR)] i )-(DR f )} / (DR i )]×100 (In the mathematical formula, the deposition rate (DR, Å / cycle) is the rate at which ultrathin films are deposited. In the deposition process of ultrathin films formed through precursors and modifying gases, the initial deposition rate (DR) is...) i The final deposition rate (DR) is the deposition rate of ultrathin films formed without the introduction of a modifying gas. f) is the deposition rate of the ultrathin film formed by introducing modified gas during the process described above. The deposition rate (DR) is a value measured using an ellipsometer under normal temperature and pressure conditions for ultrathin films with a thickness of less than 10 nm or less than 5 nm, and the unit is Å / cycle.

[0137] In the mathematical formula 1, with or without the use of modified gas, the growth rate of each ultrathin film per cycle refers to the ultrathin film deposition thickness (Å / cycle) of each cycle, that is, the deposition rate. As an example, the deposition rate can be obtained by measuring the final thickness of the ultrathin film with a thickness of less than 10 nm or less than 5 nm using an ellipsometry under normal temperature and pressure conditions, and then dividing it by the total number of cycles to obtain the average deposition rate.

[0138] In the mathematical formula 1, "when no modified gas is used" refers to the case where the thin film is prepared by simply adsorbing the precursor compound on the substrate in the ultrathin film deposition process. As a specific example, it refers to the case where the ultrathin film formation method omits the steps of adsorbing the modified gas and the steps of not adsorbing the modified gas to form the thin film.

[0139] As an example, the ultrathin film formation method can be carried out at a deposition temperature in the range of 100°C to 600°C, preferably in the range of 300°C to 500°C, and more preferably in the range of 300°C to 400°C, within which the ALD process characteristics are provided while achieving excellent film quality.

[0140] As an example, the ultrathin film formation method can be carried out at a deposition pressure in the range of 0.01 Torr to 20 Torr, preferably in the range of 0.1 Torr to 20 Torr, more preferably in the range of 0.1 Torr to 10 Torr, and most preferably in the range of 0.3 Torr to 7 Torr. Within this range, it has the effect of obtaining an ultrathin film with uniform thickness.

[0141] In this invention, the deposition temperature and deposition pressure can be measured as the temperature and pressure formed in the deposition chamber, or as the temperature and pressure applied to the substrate in the deposition chamber.

[0142] Preferably, the ultrathin film formation method may include the following steps: heating the temperature inside the chamber to the deposition temperature before introducing the precursor material into the chamber; and / or purging the chamber by injecting an inactive gas before introducing the precursor material into the chamber.

[0143] In the ultrathin film formation method, the intensity (c / s) of residual impurities (carbon or halogen elements) in the ultrathin film, based on an ultrathin film thickness of 100 angstroms as determined by SIMS, is preferably 100,000 or less, more preferably 70,000 or less, even more preferably 50,000 or less, and most preferably 10,000 or less. As a preferred embodiment, it can be 5,000 or less, more preferably 10 to 4,000, and even more preferably 10 to 3,000. Within this range, it is effective in preventing the deterioration of crystallinity and electrical properties.

[0144] Additionally, if necessary, the modification step can be performed before the adsorption step.

[0145] That is, a method for forming an ultrathin film can be provided, characterized in that the method includes: a modification step, forming a modified material on a substrate by spraying a modifying gas; an adsorption step, forming an adsorbent material on the substrate by spraying a source gas composed of one or more materials selected from barrier materials and high dielectric materials onto the substrate; and a deposition step, depositing a thin film composed of one or more materials selected from barrier materials and high dielectric materials on the substrate by spraying a reactive gas that reacts with the adsorbent material; when the adsorption step, modification step and deposition step are combined into a cycle, the following conditions are simultaneously met: the thickness of the thin film formed after repeating 10 cycles is less than 10 angstroms, and the thickness of the thin film formed after repeating 20 cycles is less than 20 angstroms.

[0146] In addition, the present invention can provide a method for forming ultrathin films, characterized in that, in order to modify the surface or the adsorbed source material, a compound with a bond dissociation energy of less than 350 kJ / mol between the central metal atom and the ligand is used, wherein the bond dissociation energy is calculated using the Gaussian 16 program (DFT-D3 / B3LYP basis set (central metal, iodine: LanL2DZ, C, N, O, H, X: 6-31+G(dp))).

[0147] In addition, in this invention, the apparatus for preparing the ultrathin film formation method may include: an ALD chamber; a first vaporizer for vaporizing a precursor material; a first moving unit for transferring the vaporized precursor material into the ALD chamber; a second vaporizer for vaporizing a modified gas; a second moving unit for transferring the vaporized modified gas into the ALD chamber; and a third moving unit for transferring a reaction gas into the ALD chamber.

[0148] There are no particular limitations on the vaporizer and moving unit, as long as they are commonly used in the technical field to which this invention pertains.

[0149] As a specific example, the ultrathin film formation method is described in that, firstly, a substrate with a thin film formed on its upper part is placed in a deposition chamber capable of atomic layer deposition.

[0150] The substrate may include a semiconductor substrate, such as a silicon substrate and silicon oxide.

[0151] A conductive layer or an insulating layer may also be formed on the upper part of the substrate.

[0152] In order to deposit a thin film on a substrate located in the deposition chamber, the modified gas, precursor material, or a mixture thereof with a nonpolar solvent are prepared respectively.

[0153] Then, the prepared modified gas, precursor material, or a mixture thereof with a nonpolar solvent is injected into the vaporizer, where it is transferred to the deposition chamber and adsorbed onto the substrate by changing it into a vapor phase. Unadsorbed material (gas) is then removed through various purging steps.

[0154] Preferably, the nonpolar solvent may be selected from one or more of the group consisting of alkanes and cycloalkanes. In this case, it has the following advantages: it contains an organic solvent with low reactivity and solubility and is easy to manage in terms of moisture. At the same time, it can improve step coverage even when the deposition temperature is increased during the formation of ultrathin films.

[0155] As a more preferred example, the nonpolar solvent may contain C1 to C10 alkanes or C3 to C10 cycloalkanes, preferably C3 to C10 cycloalkanes, which have the advantages of low reactivity and solubility and easy moisture management.

[0156] In this invention, C1 and C3 refer to the number of carbon atoms.

[0157] Preferably, the cycloalkane can be a C3 to C10 monocycloalkane. Among the monocycloalkanes, cyclopentane is liquid at room temperature and has the highest vapor pressure, making it a preferred choice for vapor deposition processes, but not limited thereto.

[0158] As an example, the solubility of the nonpolar solvent in water (at 25°C) is less than 200 mg / L, preferably from 50 mg / L to 400 mg / L, and more preferably from 135 mg / L to 175 mg / L. Within this range, it has the advantages of low reactivity to precursor materials and easy moisture management.

[0159] In this invention, solubility is not particularly limited by the determination methods or standards commonly used in the technical field to which this invention pertains; for example, saturated solutions can be determined by HPLC.

[0160] Preferably, the content of the nonpolar solvent may be from 5% to 95% by weight relative to the total weight of the precursor compound and the nonpolar solvent, more preferably from 10% to 90% by weight, even more preferably from 40% to 90% by weight, and most preferably from 70% to 90% by weight.

[0161] If the content of the added nonpolar solvent exceeds the upper limit, it will induce impurities, thereby increasing the resistance and membrane impurity values. If the content of the added organic solvent is lower than the lower limit, it has the disadvantages of low step coverage improvement effect and low impurity (such as chloride (Cl) ion) reduction effect due to the addition of solvent.

[0162] As described above, as an example, the ultrathin film formation method can be performed in a unit cycle as follows: the precursor material and the modified gas are sequentially injected into the chamber and adsorbed onto the substrate surface, and the unadsorbed material is purged; the unit cycle can be repeated in order to form an ultrathin film of the desired thickness.

[0163] As an example, the unit cycle can be repeated from 1 to 99,999 times, preferably from 10 to 1,000 times, more preferably from 50 to 5,000 times, and even more preferably from 100 to 2,000 times. Within this range, it exhibits the desired membrane properties very well.

[0164] The present invention also provides a semiconductor substrate, characterized in that it is prepared by the ultrathin film formation method of the present invention, in which the substrate has excellent uniformity of film thickness and excellent density and electrical properties.

[0165] As one example, the thickness of the ultrathin film can be less than 10 nm, as another example, it can be less than 5 nm, and as a specific example, it can be from 0.001 nm to 5 nm, preferably from 0.01 nm to 1.5 nm. Within this range, it has excellent barrier properties or high dielectric properties while providing the excellent properties of an ultrathin film with extremely thin film thickness.

[0166] As an example, taking a 1.5 nm ultrathin film as a reference, the resistivity of the ultrathin film can be from 0.1 μΩ·cm to 1000 μΩ·cm, preferably from 0.1 μΩ·cm to 900 μΩ·cm, and more preferably from 0.1 μΩ·cm to 800 μΩ·cm. Within this range, it has excellent film properties.

[0167] Preferably, the impurity content of the ultrathin film can be below 10,000 ppm or from 1 ppm to 9,000 ppm, more preferably from 1 ppm to 8,500 ppm, and even more preferably from 1 ppm to 1,000 ppm. Within this range, it exhibits excellent film crystallinity and improves resistivity. The impurities remaining in the ultrathin film are those resulting from inadequate reduction of the metal precursor ligand. For example, these can be carbon, nitrogen, oxygen, or halogen elements. The lower the amount of residual impurities in the ultrathin film, the better the film quality.

[0168] The ultrathin film is characterized in that, when the impurity content of the ligand-derived film is determined by XPS, impurities such as carbon are reduced to below 1%.

[0169] The ultrathin film is characterized by satisfying the following conditions: after immersion in hydrofluoric acid (HF, 1% dilution) for 5 minutes, the maximum etch height of the film from the top to the bottom (the side closest to the substrate), as measured by a scanning probe microscope (atomic force microscope, AFM), is less than 50% by etching evaluation; and no pinholes are generated in the film even after etching.

[0170] The ultrathin film is characterized by meeting the following conditions: after immersion in hydrofluoric acid (HF, 1% dilution) for 5 minutes, the maximum etch height of the film from the top to the bottom (the side closest to the substrate), as measured by a scanning probe microscope (atomic force microscope, AFM), is less than 1.5 nm by etching evaluation; and no pinholes are generated in the film even after etching.

[0171] In this invention, unless otherwise mentioned, % refers to weight.

[0172] As an example, the ultrathin film has a step coverage of 90% or more, preferably 92% or more, and more preferably 95% or more. Within this range, even complex structures can be easily deposited on the substrate, thus having the advantage of being suitable for next-generation semiconductor devices.

[0173] The thickness of the prepared ultrathin film is preferably less than 1.5 nm. Based on the ultrathin film of 1.5 nm, the impurity content (carbon, nitrogen, oxygen and halogen, etc.) is less than 10,000 ppm and the step coverage is more than 90%. Within this range, it has excellent performance as a barrier film, dielectric film or blocking film, but is not limited to this.

[0174] The ultrathin film is characterized by improved crystallinity as determined by XRD.

[0175] The ultrathin film is characterized by improved resistivity.

[0176] Hereinafter, embodiments of the thin film of the present invention will be described in detail.

[0177] The thin film of the present invention can be prepared by the ultrathin film formation method of the present invention described above.

[0178] The thin film of the present invention may include a thin film layer formed on a substrate.

[0179] The thin film layer can be formed on the substrate using a mixture including a barrier material or a high dielectric material.

[0180] The thickness of the thin film layer, as measured by TEM, meets the requirements of less than 10 Å / 10 cycles and less than 20 Å / 10 cycles. After immersion in hydrofluoric acid (HF, 1% dilution) for 5 minutes, a thin film with a surface roughness of less than 0.3 nm as measured by tilted SEM can be provided. Thus, the thin film of the present invention can be made to form a thinner thickness and has a dielectric constant that reduces current leakage or improves electrical properties, thereby contributing to the fabrication of finer and thinner semiconductor devices.

[0181] The thin film layer can be deposited on the substrate through the adsorption step, the modification step, and the deposition step.

[0182] The thin film layer comprises a thin film formed on a substrate using one or more materials selected from barrier materials and high dielectric materials, the thin film satisfying the following conditions: a thickness of less than 10 Å / 10 cycles and less than 20 Å / 10 cycles as measured by TEM, and a surface roughness of less than 0.3 nm as measured by tilted SEM after immersion in hydrofluoric acid (HF, 1% dilution) for 5 minutes.

[0183] The thin film is selected from one or more of the following: titanium nitride film, tantalum nitride film, ruthenium, aluminum oxide film, calcium oxide film, yttrium oxide film, strontium oxide film, zirconium oxide film, hafnium oxide film, tantalum oxide film, lanthanum oxide film, barium oxide, and titanium oxide film.

[0184] After the ultrathin film was immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes, it was evaluated by etching. The maximum etching height of the film from the top to the bottom (the side closest to the substrate) was less than 50%, as measured by scanning probe microscopy (atomic force microscopy, AFM), confirming that no pinholes were generated.

[0185] After the ultrathin film was immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes, it was evaluated by etching. The maximum etching height of the film from the top to the bottom (the side closest to the substrate) was less than 1.5 nm, as measured by scanning probe microscopy (atomic force microscopy, AFM), confirming that no pinholes were generated.

[0186] In this case, compared with the absence of the modification step, the thin film of the present invention can be realized to have a resistance or dielectric constant suitable for use as an electrode or dielectric film, while forming a thinner and denser and more uniform thin film, thereby improving the quality of the ultrathin film and ensuring a variety of applicable scenarios.

[0187] The thin film layer may be formed of a barrier material and / or a high-dielectric-rate material, and modified using a modifying gas. When modified with a modifying gas, impurities are removed from the film, the bonds of materials with low bonding strength break, leaving only materials with high bonding strength. Thus, the thin film of the present invention can achieve a thinner thickness and improved quality through film densification, crystallization, and impurity removal.

[0188] The following are two specific experimental examples, but these are just examples and are not limited to these.

[0189] Example 1 As a specific example, 5N HI was used as the modifying gas and TiCl4 was used as the precursor material to carry out the following ultrathin film formation process.

[0190] Specifically, the prepared precursor material is placed in a separate container and supplied at room temperature using a Liquid Mass Flow Controller (LMFC) at a flow rate of 0.1 g / min to a separate vaporizer heated to 150°C. The TiCl4 precursor, vaporized in the vaporizer, is then introduced into the deposition chamber for 3 seconds, followed by argon gas supply at 5000 sccm for 10 seconds and argon purging. During this process, the pressure within the reaction chamber is controlled at 2.5 Torr.

[0191] Next, the prepared modified gas is loaded into a container and supplied to the chamber at a flow rate of 1000 sccm using a mass flow controller (MFC) at room temperature. The modified gas, vaporized in the vaporizer, is then introduced into the deposition chamber containing the substrate for 2 seconds to undergo a reduction reaction. Afterward, argon gas is supplied at 5000 sccm for 10 seconds, followed by argon purging. During this time, the pressure within the reaction chamber is controlled at 2.5 Torr.

[0192] Next, NH3, used as a preparatory reaction gas, is supplied to the chamber at a flow rate of 1000 sccm. The reaction gas, vaporized in the vaporizer, is introduced into the deposition chamber containing the substrate for 2 seconds to carry out the reduction reaction. Then, argon gas is supplied at 5000 sccm for 10 seconds and argon purging is performed. At this time, the pressure in the reaction chamber is controlled at 2.5 Torr.

[0193] The deposition temperature is maintained at 500°C, and this process is repeated 10 to 400 times to form an atomic layer thin film.

[0194] For the prepared ultrathin film (TiN film), the film thickness, resistivity and surface roughness for each deposition cycle were measured and are shown in Table 1.

[0195] Specifically, the thickness of the ultrathin film (TiN film) was measured using a transmission electron microscope (TEM), as shown in Table 1 below, and met the requirements of less than approximately 10 Å / 10 cycles and less than approximately 20 Å / 10 cycles.

[0196] For reference, the following Figure 1 This is a graph comparing the film formation thickness of embodiments of the present invention with that of comparative examples of the prior art, and by changing parameters, in the following... Figure 2 The thickness of the film formed in each deposition cycle is also shown.

[0197] For reference, the following Figure 3 This is an etching evaluation result between an embodiment of the present invention and a comparative example of the prior art. After immersion in hydrofluoric acid (HF, 1% dilution) for 5 minutes, a scanning electron microscope (SEM) image showing the etching evaluation result is displayed.

[0198] Furthermore, for the prepared ultrathin film (TiN film), the surface roughness measured by AFM was calculated to be below 0.3 nm according to the immersion time in hydrofluoric acid (HF, 1% dilution) before, 1 minute, 5 minutes, and 10 minutes, as follows. Figure 4 As shown.

[0199] In addition, it was observed that after the ultrathin film was immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes, the maximum etching height of the film from the top to the bottom (the side closest to the substrate) was less than 50% as measured by etching evaluation using scanning probe microscopy (atomic force microscopy (AFM)).

[0200] In addition, it was observed that after the ultrathin film was immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes, the maximum etching height of the film from the top to the bottom (the side closest to the substrate) was less than 1.5 nm, as measured by scanning probe microscopy (atomic force microscopy, AFM).

[0201] Furthermore, using the following mathematical formula 1, the results of measuring the deposition rate increase (GPC) confirmed an improvement of over 30%.

[0202] [Mathematical Expression 1] deposition rate increase rate = [{(DR)] i )-(DR f )} / (DR i )]×100 (In the mathematical formula, the deposition rate (DR, Å / cycle) is the rate at which the ultrathin film is deposited. In the deposition process of ultrathin films formed through precursors and modifying gases, the initial deposition rate (DR) is...) i The final deposition rate (DR) is the deposition rate of ultrathin films formed without the introduction of a modifying gas. f The deposition rate (DR) is the deposition rate of the ultrathin film formed by introducing modified gas during the process described above. The deposition rate (DR) is a value measured using an ellipsometer under ambient temperature and pressure conditions for ultrathin films with a thickness of less than 10 nm or less than 5 nm, and the unit is Å / cycle. Table 1

[0203] (In the table, "cannot be measured" refers to the range where the resistivity is too high to be measured by the equipment.) Comparative Example 1 The modification step of introducing the modifying gas was omitted. Otherwise, the same process as in Example 1 was repeated, and the same measurement results as in Example 1 are shown in Table 2 below.

[0204] For the prepared thin film (TiN film), the thickness of the film measured by an ellipsometer (a device that can use the polarization properties of light to determine the optical properties (such as thickness or refractive index) of the metal film) was divided by the number of cycles. The results of calculating the thickness of the metal film deposited per cycle showed less than 6 Å / 10 cycles and less than 10 Å / 10 cycles, thus confirming a poor initial film formation rate lower than that of the ultrathin films in Examples 1 to 2.

[0205] In addition, for the prepared ultrathin film (TiN film), the surface resistivity was measured using the four-probe measurement method, and the specific resistivity was calculated using the measured thickness.

[0206] Furthermore, for the prepared ultrathin film (TiN film), the surface roughness, as measured by AFM, increased with immersion time after immersion in hydrofluoric acid (HF, 1% dilution), as follows: Figure 4 As shown, when immersed for 10 minutes, the wavelength was calculated to be more than 0.4 nm, which was considered defective compared to Example 1.

[0207] In addition, it was observed that after the ultrathin film was immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes, the maximum etch height of the film from the top to the bottom (the side closest to the substrate) exceeded 90% by etching evaluation using scanning probe microscopy (atomic force microscopy (AFM)).

[0208] In addition, it was observed that after the ultrathin film was immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes, the maximum etching height of the film from the top to the bottom (the side closest to the substrate) exceeded 1.5 nm by etching evaluation, measured by scanning electron microscopy (SEM) and scanning probe microscopy (Atomic Force Microscope (AFM)).

[0209] Furthermore, using the aforementioned mathematical formula 1, the results of measuring the deposition rate increase (GPC) confirm that the value is significantly lower than 30%.

[0210] Table 2

[0211] (In the table, "cannot be measured" refers to the range where the resistivity is too high to be measured by the equipment.) As shown in Tables 1 and 2, according to the present invention, it has been confirmed that the thickness of each deposition cycle is very high, the critical thickness for measuring resistivity is relatively low, and the surface roughness is improved because a flat film is formed at a thinner thickness.

[0212] Example 2 The modified gas was introduced before the adsorption step, and the same process as in Example 1 was repeated.

[0213] For the prepared ultrathin film (TiN film), the film thickness measured by TEM is divided by the number of cycles to calculate the thickness of the metal film deposited in one cycle, and the result is less than 10 Å / 10 cycles and less than 20 Å / 10 cycles.

[0214] In addition, for the prepared ultrathin film (TiN film), the surface resistivity was measured using the four-probe measurement method, and the specific resistivity was calculated using the measured thickness.

[0215] Furthermore, the prepared ultrathin film (TiN film) was immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes, and the results of tilted SEM measurements confirmed that there were no pinholes.

[0216] In addition, it was observed that after the ultrathin film was immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes, the maximum etching height of the film from the top to the bottom (the side closest to the substrate) was less than 50% as measured by etching evaluation using scanning probe microscopy (atomic force microscopy (AFM)).

[0217] In addition, it was observed that after the ultrathin film was immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes, the maximum etching height of the film from the top to the bottom (the side closest to the substrate) was less than 1.5 nm, as measured by scanning probe microscopy (atomic force microscopy, AFM).

[0218] Furthermore, using the aforementioned mathematical formula 1, the results of measuring the deposition rate increase (GPC) confirm that the value significantly exceeds 30%.

[0219] The results from Examples 1 to 2 confirm that an ultrathin film can be provided, which differs from Comparative Example 1 of the prior art. When a special modifying gas is used in a precursor material with a specified bond dissociation energy, the following conditions are met: the thickness measured by TEM is less than 10 Å / 10 cycles and less than 20 Å / 10 cycles, thereby improving the initial film formation rate. At the same time, after immersion in hydrofluoric acid (HF, 1% dilution) for 5 minutes, the surface roughness measured by tilted SEM is less than 0.3 nm, etc., which can achieve film densification (no pinholes) and homogenization.

[0220] Furthermore, it can be confirmed that not only is the resistivity improved, but the impurities remaining in the thin film are also reduced.

[0221] In addition to the aforementioned TiN (titanium nitride film), it has been confirmed that tantalum nitride film, aluminum oxide film, calcium oxide film, yttrium oxide film, strontium oxide film, zirconium oxide film, hafnium oxide film, tantalum oxide film, lanthanum oxide film, barium oxide film, and titanium oxide film can also be provided. Furthermore, it has been confirmed that an ultrathin film with denser and more uniform film can be provided, and it has been confirmed that not only is the resistivity improved, but the impurities remaining in the film are also reduced.

[0222] Furthermore, it was confirmed that the aforementioned TiN (titanium nitride film), tantalum nitride film, aluminum oxide film, calcium oxide film, yttrium oxide film, strontium oxide film, zirconium oxide film, hafnium oxide film, tantalum oxide film, lanthanum oxide film, barium oxide film, and titanium oxide film, after being immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes, were evaluated by etching. The maximum etching height from the top to the bottom (the side closest to the substrate) of the film, measured by scanning probe microscopy (AFM), was less than 50%. At the same time, after being immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes, the maximum etching height from the top to the bottom (the side closest to the substrate), measured by scanning probe microscopy (AFM), was less than 1.5 nm.

[0223] In other words, in the modified gases represented by the chemical formulas 1-1 to 1-12, the results of calculating the bond dissociation energies of carbon or hydrogen compounds bonded to iodine are shown in Table 3 below.

[0224] Table 3

[0225] Furthermore, as a computer simulation confirmation experiment, the energy value of the transition structure was calculated using the Gaussian 16 program (based on the DFT-D3 / B3LYP basis set (central metal, iodine, chlorine: LanL2DZ, C, N, O, H, Si: 6-31+G(dp)) and optimized by TS (Berny).

[0226] Specifically, silica clusters (SiO2 cluster (Si9H)) 12 The -(OH)2)) model was used as a substrate to optimize the structure of the MoCl5 precursor adsorption form. The activation energies required for the reactions with H2 and HI were calculated. The model based on the measurement results is illustrated in Table 4 below.

[0227] The activation energy value calculated by the computer simulation is defined as the minimum energy (Ea) required to proceed from the state (Ads) where the precursor material is chemically adsorbed on the substrate to the product (final) reaction path, i.e., the energy difference to the activated state (TS), and the energy of each state is calculated and confirmed.

[0228] When forming TiN thin films, the results of the evaluation of the deposition rate, average resistivity, and resistivity change compared with the unused case in Comparative Example 1 for the inventive materials used to reduce the reactive energy of TiCl4 and NH3 reaction gas during the formation of TiN thin films are shown in Table 4 below.

[0229] Table 4

[0230] As shown in Table 4, it can be confirmed that the degree of resistivity degradation increases with the increase of the bond dissociation energy between carbon and iodine.

[0231] Ultimately, it was confirmed that when providing ultrathin films from barrier materials and / or high dielectric materials, the modification steps, including the deposition of precursor materials with specific bond dissociation energies using a specified modified gas, improve film densification and uniformity along with the initial film yield. This prevents pinholes during etching evaluation and prevents the inflow of film impurities caused by ligands such as carbon. It is also suitable for providing improvements in film quality, such as electrical properties and crystallinity.

Claims

1. An ultrathin film, characterized in that, This includes thin films formed on a substrate using one or more materials selected from barrier materials and high dielectric materials. The thickness of the thin film, as measured by TEM, is less than 10 nm. The square root average surface roughness of the thin film is less than 0.3 nm.

2. An ultrathin film, characterized in that, This includes thin films formed on a substrate using one or more materials selected from barrier materials and high dielectric materials. The thickness of the thin film, as measured by TEM, is less than 5 nm. By using modified gases, the deposition rate was increased by more than 30%.

3. The ultrathin film according to claim 1 or 2, characterized in that, The surface roughness of the film, measured by scanning probe microscopy (atomic force microscopy, AFM), was less than 0.3 nm after immersion in hydrofluoric acid (HF, 1% dilution) for 5 minutes.

4. The ultrathin film according to claim 1 or 2, characterized in that, The thin film is selected from one or more of the following: titanium nitride film, tantalum nitride film, ruthenium film, aluminum oxide film, calcium oxide film, yttrium oxide film, strontium oxide film, zirconium oxide film, hafnium oxide film, tantalum nitride film, lanthanum oxide film, barium oxide film, and titanium oxide film.

5. The ultrathin film according to claim 1 or 2, characterized in that, After the film was immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes, the maximum etch height of the film from the top to the bottom (the side closest to the substrate) was less than 50% as measured by etching evaluation using a scanning probe microscope (atomic force microscope, AFM).

6. The ultrathin film according to claim 1 or 2, characterized in that, After the film was immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes, the maximum etching height of the film from the top to the bottom (the side closest to the substrate) was less than 1.5 nm, as measured by scanning probe microscopy (atomic force microscopy).

7. A method for forming an ultrathin film, characterized in that, include: The adsorption step involves forming an adsorbent material on the substrate by spraying a source gas composed of one or more materials selected from barrier materials and high dielectric materials. The modification step involves modifying the adsorbent material formed on the substrate by injecting a modifying gas that reacts with the source gas, and... The deposition step involves depositing a thin film composed of one or more materials selected from barrier materials and high dielectric materials on the substrate by spraying a reactive gas that reacts with the modified gas. When the adsorption step, modification step and deposition step are considered as a cycle, the ultrathin film simultaneously meets the following conditions: the thickness of the film formed after 10 cycles is less than 10 angstroms, and the thickness of the film formed after 20 cycles is less than 20 angstroms.

8. A method for forming an ultrathin film, characterized in that, include: The modification step involves spraying a modifying gas onto the substrate surface, where it undergoes an adsorption reaction with the source gas, thereby modifying the surface. The adsorption step involves forming an adsorbent material on a substrate by spraying a source gas composed of one or more materials selected from barrier materials and high dielectric materials. The deposition step involves depositing a thin film composed of one or more materials selected from barrier materials and high dielectric materials on the substrate by spraying a reactive gas that reacts with the source gas. When the modification step, adsorption step and deposition step are combined into one cycle, the ultrathin film simultaneously meets the following conditions: the thickness of the film formed after 10 cycles is less than 10 angstroms, and the thickness of the film formed after 20 cycles is less than 20 angstroms.

9. The method for forming ultrathin films according to claim 7 or 8, characterized in that, In the adsorption step, the source gas is selected from one or more of titanium, tantalum, aluminum, ruthenium, niobium, bismuth, calcium, yttrium, strontium, zirconium, hafnium, lanthanum and barium.

10. The method for forming ultrathin films according to claim 7 or 8, characterized in that, In the modification step, a halogen gas containing iodine and having a weight-average molecular weight of 127 g / mol to 250 g / mol is sprayed onto the substrate as a modifying gas.

11. The method for forming ultrathin films according to claim 10, characterized in that, The modified gas includes materials having direct bonds between hydrogen (H) and iodine, materials having direct bonds between carbon (C) and iodine, or materials having direct bonds between halogens (F, Cl, Br) and iodine.

12. The method for forming ultrathin films according to claim 11, characterized in that, The material having direct bonds of hydrogen (H) and iodine, the overall binding energy of the compound calculated using the Gaussian 16 program (DFT-D3 / B3LYP basis set (iodine: LanL2DZ, carbon, hydrogen: 6-31+G(dp)) is 305 kJ / mol to 325 kJ / mol.

13. The method for forming ultrathin films according to claim 11, characterized in that, The material having direct bonds between carbon (C) and iodine, using the Gaussian 16 program (DFT-D3 / B3LYP basis set (iodine: LanL2DZ, carbon, hydrogen: 6-31+G(dp)), the overall binding energy of the compound is calculated to be between 165 kJ / mol and 242 kJ / mol, and it exhibits a tertiary structure.

14. The method for forming ultrathin films according to claim 11, characterized in that, The material having direct bonds between halogens (F, Cl, Br) and iodine is processed using Gaussian 16 equations. The overall binding energy of the compound calculated from the basis set of DFT-D3 / B3LYP (iodine: LanL2DZ, carbon and hydrogen: 6-31+G(dp)) is 50 kJ / mol to 160 kJ / mol.

15. The method for forming ultrathin films according to claim 7 or 8, characterized in that, In the deposition step, ozone, oxygen, nitrogen, or ammonia is sprayed onto the substrate as a reactive gas.

16. The method for forming ultrathin films according to claim 7 or 8, characterized in that, include: In the first purging step, after the adsorption step, purging gas is sprayed onto the substrate. The second purging step involves spraying purging gas onto the substrate after the modification step, and... The third purging step involves spraying purging gas onto the substrate after the deposition step.

17. A method for forming an ultrathin film, characterized in that, To modify the surface or adsorbed source material, compounds with a bond dissociation energy of less than 350 kJ / mol between the central metal atom and the ligand were used. The bond dissociation energy was calculated using the Gaussian 16 program (based on the basis set of DFT-D3 / B3LYP (central metal, iodine: LanL2DZ, C, N, O, H, X: 6-31+G(dp)).

18. A semiconductor substrate, characterized in that, Including the ultrathin film according to claim 1 or 2.

19. A semiconductor device, characterized in that, Includes the semiconductor substrate according to claim 18.

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