Ultrathin film, method for forming ultra-thin film, and semiconductor substrate and semiconductor device manufactured therefrom

Abstract

The present invention relates to an ultrathin film, a method for forming the ultrathin film, and a semiconductor substrate and a semiconductor device including same. Not only being composed of a barrier material and / or a high dielectric constant material, but also being modified to improve initial reactivity of deposition, the film, even when formed to be extremely thin, can reduce current leakage or improve current characteristics. Additionally, densification and impurity removal contribute to enhanced quality. The invention has the effect of providing an ultrathin film, a method for forming the ultrathin film, a forming agent, and a semiconductor substrate and a semiconductor device each including same.

Description

Ultra-thin film, ultra-thin film forming method, semiconductor substrate and semiconductor device manufactured thereby

[0001] The present invention relates to an ultra-thin film, a method for forming an ultra-thin film, a semiconductor substrate and a semiconductor device manufactured therefrom, and more particularly, to an ultra-thin film, a method for forming an ultra-thin film, a forming agent, a semiconductor substrate and a semiconductor device including the same, which are formed not only of a barrier material and / or a high-k material but also modified to improve the initial reactivity of deposition, thereby further reducing current leakage or further improving current characteristics even when formed with an extremely thin thickness, and implementing improved quality through densification, impurity removal, etc.

[0002] As the performance of semiconductor devices improves and higher integration is required, the thickness of the deposited material decreases, causing many problems such as increased resistivity and pin holes caused by post-processing.

[0003] In particular, it is very difficult to form a barrier metal electrode in a uniform film shape at a thickness of 1.5 nm or less, so a thick film is formed.

[0004] Therefore, there is a need for the development of an ultra-thin film formation technology that can effectively form an ultra-thin film regardless of a barrier material or a high-k material and provide a dense film that does not generate pinholes during etching evaluation.

[0005] [Prior Art Literature]

[0006] [Patent Document]

[0007] Korean Patent Publication No. 2016-0022792

[0008] In order to solve the problems of the prior art as described above, the present invention aims to provide an ultra-thin film, an ultra-thin film forming method, a forming agent, a semiconductor substrate and a semiconductor device including the same, which are formed not only of a barrier material and / or a high-k material but also modified to improve the initial reactivity of deposition, thereby further reducing current leakage or improving current characteristics even when formed with an extremely thin thickness, and implementing improved quality through densification, impurity removal, etc.

[0009] The above and other objects of the present invention can all be achieved by the present invention described below.

[0010] In order to achieve the above object, the present invention comprises a thin film formed on a substrate using at least one material selected from I) a barrier material and a high-k material, wherein the thin film has a thickness of 10 nm or less as measured using TEM, and the thin film is characterized in that it has a root mean square surface roughness of 0.3 nm or less.

[0011] In addition, the present invention provides an ultra-thin film including a thin film formed on a substrate using at least one material selected from II) a barrier material and a high-k material, and characterized in that the film has a thickness of 5 nm or less as measured using TEM and a GPC value increased by 30% or more using a modifying gas.

[0012] III) In the above I) to II), the thin film may have a surface roughness of 0.3 nm or less as measured by an atomic force microscope (AFM) after immersion in hydrofluoric acid (HF, 1% dilution) for 5 minutes.

[0013] IV) In the above I) to III), the thin film may be at least one selected from a titanium nitride film, a tantalum nitride film, a ruthenium, an aluminum oxide film, a calcium oxide film, a yttrium oxide film, a strontium oxide film, a zirconium oxide film, a hafnium oxide film, a tantalum oxide film, a lanthanum oxide film, a barium oxide, and a titanium oxide film.

[0014] V) In the above I) to IV), the thin film may be a multi-element oxide film of two or more elements having a perovskite structure or a pyrochlore structure.

[0015] VI) In the above I) to V), the thin film may have a maximum etching height from the top to the bottom (substrate side) of 50% or less as measured by an atomic force microscope (AFM) through an etching evaluation after immersion in hydrofluoric acid (HF, 1% dilution) for 5 minutes.

[0016] VII) In the above I) to VI), the thin film may have a maximum etching height from the top to the bottom (substrate side) of 1.5 nm or less as measured by an atomic force microscope (AFM) through an etching evaluation after immersion in hydrofluoric acid (HF, 1% dilution) for 5 minutes.

[0017]

[0018] In addition, the present invention provides a method for forming an ultra-thin film, comprising: VIII) an adsorption step of forming an adsorbent material on a substrate by injecting a source gas composed of at least one material selected from among a barrier material and a high-k material; a modification step of modifying the adsorbent material formed on the substrate by injecting a modification gas that reacts with the source gas; and a deposition step of depositing a thin film composed of at least one material selected from among a barrier material and a high-k material on the substrate by injecting a reaction gas that reacts with the modification gas; and when the adsorption step, the modification step, and the deposition step are considered as one cycle, the thickness of the thin film formed when repeating 10 cycles is 10 Å or less, and the thickness of the thin film formed when repeating 20 cycles is 20 Å or less.

[0019] In addition, the present invention provides a method for forming an ultra-thin film, comprising: IX) a modification step of injecting a modification gas onto a substrate surface to modify the surface when an adsorption reaction occurs with a source gas on the substrate; and an adsorption step of injecting a source gas composed of at least one material selected from among a barrier material and a high-k material to form an adsorption material on the substrate; and a deposition step of injecting a reaction gas that reacts with the source gas to deposit a thin film composed of at least one material selected from among a barrier material and a high-k material on the substrate; and when the modification step, the adsorption step, and the deposition step are performed as one cycle, the thickness of the thin film formed when repeating 10 cycles is 10 Å or less, and the thickness of the thin film formed when repeating 20 cycles is 20 Å or less.

[0020] X) In the above VIII) to IX), the adsorption step may be performed using at least one 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) as a source gas.

[0021] XI) In the above VIII) to X), the source gas may be a compound having a bond dissociation energy between the central metal atom and the ligand of 350 kJ / mol or less, calculated using the Gaussian 16 program (DFT-D3 / B3LYP basis set (central metal, iodine: LanL2DZ, C, N, O, H, X: 6-31+G(dp)) to reduce the central metal atom at a low process temperature of 400°C or less.

[0022] XII) In the above VIII) to XI), the modification step can be performed by spraying a halogen gas containing iodine and having a weight average molecular weight of 127 to 250 g / mol as a modification gas onto the substrate.

[0023] XIII) In the above VIII) to XII), the reformed gas may include a material having a direct bond between hydrogen (H) and iodine, a material having a direct bond between carbon (C) and iodine, or a material having a direct bond between a halogen element (F, Cl, Br) and iodine.

[0024] XIV) In the above VIII) to XIII), the material having a direct bond between hydrogen (H) and iodine may be a material having a total binding energy of the compound calculated using the basis set (iodine: LanL2DZ, carbon, hydrogen element: 6-31+G(dp)) of the Gaussian 16 program (DFT-D3 / B3LYP) within the range of 305 to 325 kJ / mol.

[0025] XV) In the above VIII) to XIV), the substance having a direct bond between carbon (C) and iodine may be a substance exhibiting a tertiary structure, wherein the total binding energy of the compound calculated using the basis set (iodine: LanL2DZ, carbon, hydrogen element: 6-31+G(dp)) of the Gaussian 16 program (DFT-D3 / B3LYP) is 165 to 242 kJ / mol.

[0026] XVI) In the above VIII) to XV), the material having a direct bond between the halogen element (F, Cl, Br) and iodine may be a material having a total binding energy of the compound calculated using the basis set (iodine: LanL2DZ, carbon, hydrogen element: 6-31+G(dp)) of the Gaussian 16 program (DFT-D3 / B3LYP) within the range of 50 to 160 kJ / mol.

[0027] XVII) In the above VIII) to XVI), the deposition step can be performed by spraying ozone (O3), oxygen (O2), nitrogen (N2), or ammonia (NH3) as a reaction gas onto the substrate.

[0028] XVIII) In the above VIII) to XVII), the ultra-thin film forming method may include a first purge step of injecting a purge gas onto the substrate after the adsorption step is performed; a second purge step of injecting a purge gas onto the substrate after the modification step is performed; and a third purge step of injecting a purge gas onto the substrate after the deposition step is performed.

[0029]

[0030] In addition, the present invention provides a method for forming an ultra-thin film characterized in that it uses a compound having a bond dissociation energy between a central metal atom and a ligand of 350 kJ / mol or less, calculated using a basis set (central metal, iodine: LanL2DZ, C, N, O, H, X: 6-31+G(dp)) of Gaussian 16 program (DFT-D3 / B3LYP) to modify a surface or adsorbed source.

[0031] In addition, the present invention provides a semiconductor substrate characterized by including the ultra-thin film described above XX).

[0032] XXI) In the above XX), the ultra-thin film may have a multilayer structure of two or three layers.

[0033] In addition, the present invention provides a semiconductor device characterized by including the semiconductor substrate described above XXII).

[0034] According to the present invention, there is provided an ultra-thin film, an ultra-thin film forming method, a forming agent, a semiconductor substrate and a semiconductor device including the same, which are formed to an extremely thin thickness by not only making the film out of a barrier material and / or a high-k material but also modifying the film to improve the initial reactivity of the deposition, thereby further reducing current leakage or improving current characteristics, and also realizing improved quality through densification, impurity removal, etc.

[0035] Furthermore, it has the effect of improving impurities and film quality to provide a high-quality ultra-thin film forming method and a semiconductor substrate manufactured therefrom.

[0036] Figures 1 and 2 are graphs comparing the thickness of a thin film formed between an example according to the present invention and a comparative example according to the prior art.

[0037] FIG. 3 is a scanning electron microscope (SEM) photograph showing the etching evaluation results after immersion in hydrofluoric acid (HF, 1% diluted solution) for 5 minutes as an etching evaluation result between an example according to the present invention and a comparative example according to the prior art.

[0038] FIG. 4 is an atomic force microscope (AFM) photograph showing the results of etching evaluations by time of immersion in hydrofluoric acid (HF, 1% diluted solution) as a comparison between an example according to the present invention and a prior art example.

[0039] Hereinafter, the ultra-thin film, ultra-thin film forming method, etc. of this invention are described in detail.

[0040] In this document, the term “ultra-thin film” refers to a thin film made of a barrier material or a high-k material having a thickness of 10 / 10cycles or less and 20 / Refers to satisfying 10 cycles or less simultaneously.

[0041] The thickness of the above thin film can be measured using TEM, but is not limited thereto.

[0042] In this document, the term “reforming gas” means an ultra-thin film forming material, unless otherwise specified.

[0043] As used herein, the term “modification” means, unless otherwise specified, that a barrier material or a high-k material and a material other than the barrier material and / or the high-k material positively interact with the reaction surface.

[0044] Here, positive interactions may include, but are not limited to, improvements in film quality such as reduced resistivity, increased density, reduced impurities, and film densification.

[0045] Unless otherwise stated herein, % refers to weight %.

[0046]

[0047] The present inventors have confirmed that an ultra-thin film can be formed with an extremely thin thickness by applying a modified material capable of improving the initial reactivity of deposition as well as a barrier material and / or a high-k material, thereby further reducing current leakage or improving current characteristics and realizing improved quality through densification, impurity removal, etc., and have dedicated themselves to related research to complete the present invention.

[0048]

[0049] The ultra-thin film according to the present invention may include a thin film formed on a substrate using one or more materials selected from a barrier material and a high-k material.

[0050] Examples of the above barrier material and / or high-k material include a titanium nitride film, a tantalum nitride film, ruthenium, an aluminum oxide film, a calcium oxide film, a yttrium oxide film, a strontium oxide film, a zirconium oxide film, a hafnium oxide film, a tantalum oxide film, a lanthanum oxide film, a barium oxide film, a titanium oxide film, etc.

[0051] The above ultra-thin film may be a multi-element oxide film of two or more elements having a perovskite structure or a pyrochlore structure.

[0052]

[0053] The ultra-thin film according to the present invention includes a thin film formed on a substrate using at least one material selected from a barrier material and a high-k material, wherein the thin film has a thickness of 10 nm or less as measured using TEM, and the thin film is characterized in that it has a root mean square surface roughness of 0.3 nm or less, and in this case, a flat ultra-thin film can be provided while exhibiting excellent initial reactivity during deposition.

[0054] In addition, the present invention includes a thin film formed on a substrate using at least one material selected from among a barrier material and a high-k material, and is characterized in that the thickness measured using TEM is 5 nm or less and GPC is increased by 30% or more using a modifying gas, and in this case, the effect of providing a flat ultra-thin film can be excellent.

[0055] The above thin film may be at least one selected from a titanium nitride film, a tantalum nitride film, an aluminum oxide film, a calcium oxide film, a yttrium oxide film, a strontium oxide film, a zirconium oxide film, a hafnium oxide film, a tantalum oxide film, a lanthanum oxide film, a barium oxide film, or a titanium oxide film.

[0056] The above thin film is characterized by having a surface roughness of 0.3 nm or less as measured by AFM after immersion in hydrofluoric acid (HF, 1% dilution) for 5 minutes, and in this case, it can provide both ultra-thin film and film density.

[0057] The above thin film is characterized in that the maximum etching height from the top to the bottom (substrate side) of the thin film, as measured by an atomic force microscope (AFM) after immersion in hydrofluoric acid (HF, 1% dilution) for 5 minutes and evaluated by etching, is, for example, 50% or less, specifically 20% or less, and preferably 0% or close to 0%. In this case, it is more preferable because it can provide both an ultra-thin film and film density.

[0058] The above thin film is characterized in that the maximum etching height from the top to the bottom (substrate side) of the thin film, as measured by an atomic force microscope (AFM) after immersion in hydrofluoric acid (HF, 1% dilution) for 5 minutes and evaluated by etching, is, for example, 2 nm or less, specifically, 1 nm or less, preferably 0 nm or close to 0 nm, and in this case, it is more preferable because it can provide both an ultra-thin film and film density.

[0059]

[0060] The above-mentioned ultra-thin film can be manufactured by including an adsorption step, a modification step, and a deposition step.

[0061] The above adsorption step forms an adsorption material on a substrate by injecting a source gas composed of at least one material selected from among a barrier material and a high-k material.

[0062] The above adsorption step can be performed by injecting the source gas onto the substrate through the first gas path of the injection unit.

[0063] The above source gas may contain 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).

[0064] The above titanium (Ti) and tantalum (Ta) correspond to barrier materials or high-dielectric materials, and the above aluminum (Al), calcium (Ca), yttrium (Y), strontium (Sr), zirconium (Zr), hafnium (Hf), lanthanum (La), and barium (Ba) all correspond to high-dielectric materials.

[0065] The above source gas may be a gas composed of a precursor material having a ligand with at least one of the 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 a central metal atom.

[0066] The above ligand can be selected so that the bond dissociation energy between the central metal atom and the ligand is within 350 kJ / mol, calculated using the Gaussian 16 program (DFT-D3 / B3LYP basis set (central metal, iodine: LanL2DZ, C, N, O, H, X: 6-31+G(dp)) to reduce the central metal atom at a low process temperature of, for example, 400°C or less for the above-mentioned precursor material.

[0067] That is, the ligand may be an element including, but not limited to, halogen (F, Cl, or Br), C, H, N, O, S, P.

[0068] The above precursor material may be, for example, a titanium precursor or a tantalum precursor.

[0069] The titanium precursor may be a titanium halide in a preferred embodiment.

[0070] The above-mentioned titanium halide may be at least one selected from the group consisting of TiF4, TiCl4, TiBr4 and TiI4, for example, and TiCl4 is preferable from an economical perspective, but is not limited thereto.

[0071] The above tantalum precursor may be, as a preferred embodiment, a halogenated tantalum or an alkyl imido tris diethyl amino tantalum (R1N=Ta(NEt2)3), wherein the alkyl may be a straight or branched chain having 1 to 5 carbon atoms.

[0072] The above halogenated tantalum may be at least one selected from the group consisting of, for example, TaF5, TaCl5, TaBr5, TaI5, and t-butylimido tris(diethylamino)tantalum (t-BuN=Ta(NEt2)3, TBTDET), and for example, TaCl5 is preferable from an economical perspective, but is not limited thereto.

[0073] The above titanium halide or tantalum halide has excellent thermal stability, does not decompose at room temperature, and has very high vapor pressure characteristics, so it can be usefully used as a precursor for ALD (atomic layer deposition) or CVD (chemical vapor deposition) to deposit a thin film.

[0074] The above precursor material can be used, for example, by mixing it with a non-polar solvent, in which case there is an advantage in that the viscosity or vapor pressure of the precursor material can be easily controlled.

[0075] As another example, the precursor material may have a structure in which ligands (L1, L2, L3, L4, L5, L6, etc.) are bonded to 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 a central metal atom.

[0076] The above ligands (L1, L2, L3, L4, L5, L6, etc.) may be iodine-free ligands.

[0077] The above L1, L2, L3, L4, L5, and L6 may be ligands composed of, for example, C, N, O, H, F, Cl, and Br.

[0078] The precursor material is a molecule having a central metal atom (M) of Mo, W, Ru, Cu, Rh, Pb, Cd, Sn, Bi, In, Ti, Ta, Ni, Mo, Nb, Zr, V, and Ga, and one or more ligands composed of C, N, O, H, F, Cl, and Br, and having a vapor pressure of 0.01 mTorr to 100 Torr at 25°C, and the effect of using the modifying gas can be maximized.

[0079] The precursor material may be, as another specific example, a molecule having at least one ligand composed of C, N, O, H, F, Cl, Br and at least one central metal atom selected from the group consisting 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), and in order to reduce the central metal atom at a low process temperature of 400°C or lower, a compound having a bond dissociation energy between the central metal atom and the ligand calculated using the basis set (central metal, iodine: LanL2DZ, C, N, O, H, X: 6-31+G(dp)) of the Gaussian 16 program (DFT-D3 / B3LYP) of the invention is less than 350 kJ / mol.

[0080] For example, when the central metal is divalent, L1 and L2 may be attached to the central metal as ligands, and when the central metal is hexavalent, L1, L2, L3, L4, L5, and L6 may be attached to the central metal, and the ligands corresponding to L1 to L6 may be the same or different.

[0081] For example, L1, L2, L3, L4, L5 and L6 may be the same or different as -H or -R, wherein -R may be linear or cyclic as C1-C10 alkyl, C1-C10 alkene, or C1-C10 alkane, and L1, L2, L3 and L4 may be formed such that the n number of L is from 2 to 6 depending on the oxidation state of the central metal.

[0082] For example, if the central metal is divalent, L1 and L2 may be attached to the central metal as ligands, and if the central metal is hexavalent, L1, L2, L3, L4, L5, and L6 may be attached to the central metal, and the ligands corresponding to L1 to L6 may be the same or different.)

[0083] As a specific example, L1, L2, L3, L4, L5 and L6 may be the same or different as -H, -OR, or -NR2, where -R may be H, C1-C10 alkyl, C1-C10 alkene, C1-C10 alkane, iPr, or TBu, in which case it has a reaction energy suitable for being replaced by the reaction gas described below.

[0084] As a specific example, L1, L2, L3, L4, L5 and L6 may be the same or different as -H or -X, where -X may be F, Cl or Br, and in this case have a reaction energy suitable for being replaced by the reaction gas described below.

[0085] As a specific example, L1, L2, L3, L4, L5 and L6 may be the same or different as -H or -R, where -R is C1-C10 alkyl, C1-C10 alkene, or C1-C10 alkane, and may have a linear or cyclic structure, and in this case, has a reaction energy appropriate for being replaced by a reaction gas described below.

[0086] As a specific example, L1, L2, L3, L4, L5 and L6 may be the same or different as -H, -OR, or -NR2, where -R may be H, C1-C10 alkyl, C1-C10 alkene, C1-C10 alkane, iPr, or tBu, in which case it has a reaction energy suitable for being replaced by a reaction gas described below.

[0087] As a specific example, L1, L2, L3, L4, L5 and L6 may be the same or different as -H or -X, where -X may be F, Cl or Br, and in this case have a reaction energy suitable for being replaced by the reaction gas described below.

[0088] The bond dissociation energy of the above precursor material is an important factor in depositing the precursor material together with the modifying gas. The computational program used to calculate the bond dissociation energy is Gaussian 16, and the computational method used here is DFT-D3 / B3LYP. The basis set is LanL2DZ for iodine and the central metal (e.g., Mo), and 6-31+G(d,p) for other elements.

[0089] The activation energy for the reaction between the above precursor material and the reactant gas was also calculated using the same method, where the transition state method was DFT / TS-Berny and the intrinsic reaction coordinate was 40 pts.

[0090] The above precursor material can be transported into the chamber by the VFC method, the DLI method, or the LDS method.

[0091] The above precursor material has an injection (supply) time (sec) on the substrate of preferably 0.01 to 10 seconds per cycle, more preferably 0.02 to 8 seconds, even more preferably 0.04 to 6 seconds, and even more preferably 0.05 to 4 seconds, and within this range, has the advantage of improved initial film formation rate, excellent step coverage, and excellent economy.

[0092] The above feeding time is based on a flow rate of 0.1 to 8,000 mg / cycle at a chamber volume of 15 to 20 L, and more specifically, based on a flow rate of 10 to 5,000 mg / cycle at a chamber volume of 18 L.

[0093]

[0094] The above ultra-thin film may contain the aforementioned film composition alone or as a selective area, but is not limited thereto, and may also contain SiH, SiOH, etc.

[0095] The above ultra-thin film can be used in semiconductor devices for purposes such as a wiring metal film or a wiring metal diffusion barrier film, for example.

[0096] The above ultra-thin film may have a resistivity in the range of 5 μΩ·cm to 1000 μΩ·cm.

[0097] In the above adsorption step, when a mixed gas containing two or more substances is sprayed onto the substrate, a first source gas containing a first substance and a second source gas containing a second substance are mixed in a buffer tank arranged spaced apart from the spray unit to create a mixed gas, which is then supplied to the spray unit and sprayed onto the substrate, or the first source gas and the second source gas may be sequentially sprayed onto the substrate. Accordingly, a thin film with improved step coverage can be produced while also having improved uniformity.

[0098]

[0099] The above modification step may occur, for example, on the entire substrate or a portion of the substrate on which the ultra-thin film to be provided is to be formed.

[0100] The above modification step can be performed using a modification gas that reacts with the source gas, and for example, the adsorbent material formed on the substrate can be modified by injecting the modification gas that reacts with the source gas.

[0101] The above-mentioned reforming gas may be, for example, a halogen gas containing iodine and having a weight average molecular weight of 127 to 250 g / mol, in which case it can provide an ultra-thin film and film density.

[0102] As a specific example, the reforming gas may use at least one of a material having a direct bond between hydrogen (H) and iodine, a material having a direct bond between carbon (C) and iodine, or a material having a direct bond between a halogen element (F, Cl, Br) and iodine.

[0103] The material having the direct bond between hydrogen (H) and iodine may be, for example, a material whose total binding energy of the compound calculated using the basis set (iodine: LanL2DZ, carbon, hydrogen element: 6-31+G(dp)) of the Gaussian 16 program (DFT-D3 / B3LYP) is within the range of 305 to 325 kJ / mol. In this case, it can provide an ultra-thin film and film density.

[0104] The material having the direct bond between the above carbon (C) and iodine may be a material having a total binding energy of 165 to 242 kJ / mol and a tertiary structure as calculated using the basis set (iodine: LanL2DZ, carbon, hydrogen elements: 6-31+G(dp)) of the Gaussian 16 program (DFT-D3 / B3LYP). In this case, it can provide an ultra-thin film and film density.

[0105] The material having a direct bond between the above halogen element (F, Cl, Br) and iodine may be a material whose total binding energy of the compound is within the range of 50 to 160 kJ / mol as calculated using the basis set (iodine: LanL2DZ, carbon, hydrogen element: 6-31+G(dp)) of the Gaussian 16 program (DFT-D3 / B3LYP). In this case, it can provide an ultra-thin film and film density.

[0106] The above-mentioned reforming gas is a compound having a direct bond between hydrogen (H) and iodine, and the total binding energy of the compound calculated using the basis set (iodine: LanL2DZ, carbon, hydrogen element: 6-31+G(dp)) of the Gaussian 16 program (DFT-D3 / B3LYP) can be 305 to 325 kJ / mol. In this case, the content of film impurities due to ligands such as carbon can be reduced and a thin film with low resistance can be effectively provided.

[0107] The above-mentioned reforming gas may be at least one selected from compounds represented by the following chemical formulas 1-1 to 1-12, and in this case, it may provide an ultra-thin film while also providing film density.

[0108] [Chemical Formulas 1-1 to 1-12]

[0109]

[0110] The above-mentioned reforming gas is, for example, a single hydrogen iodide of 3N to 15N, a gas mixture of 1 to 99 wt% of hydrogen iodide of 3N to 15N and the remainder of an inert gas so that the total amount becomes 100 wt%, or an aqueous solution mixture of 0.5 to 70 wt% of hydrogen iodide of 3N to 15N and the remainder of water so that the total amount becomes 100 wt%, wherein the inert gas may be nitrogen, helium or argon having a purity of 4N to 9N, in which case a reduction reaction is performed to reduce impurities and effectively form a thin film or a metal nitride film having low resistance.

[0111] The above-mentioned reforming gas is preferably a single hydrogen iodide of 5N to 6N, a gas mixture of 1 to 99 wt% of hydrogen iodide of 5N to 6N and the balance of an inert gas so that the total amount becomes 100 wt%, or an aqueous solution mixture of 0.5 to 70 wt% of hydrogen iodide of 5N to 6N and the balance of water so that the total amount becomes 100 wt%, wherein the inert gas may be nitrogen, helium or argon having a purity of 4N to 9N, and in this case, by suppressing side reactions during the formation of an ultra-thin film and controlling the initial film formation rate, process by-products in the ultra-thin film are reduced, so that corrosion or deterioration is reduced, and not only is an improvement in film quality such as an improvement in film crystallinity provided, but also the film thickness uniformity can be greatly improved even when a thin film is formed on a substrate having a highly integrated or complex structure.

[0112] In such cases, when forming a thin film on a substrate having a highly integrated or complex structure, the film thickness uniformity is greatly improved by sufficiently providing the effect of a reduction reaction to the precursor material adsorbed on the substrate at a relatively low process temperature at which the precursor is not thermally decomposed, and not only the precursor but also the process by-products are effectively protected by preventing adsorption, and the reaction speed is reduced, but there is an advantage of effectively removing the process by-products.

[0113] The above-mentioned reforming gas may preferably be a compound having a purity of 99.9% or higher, a compound having a purity of 99.95% or higher, or a compound having a purity of 99.99% or higher. For reference, when using a compound having a purity of less than 99%, impurities may remain in the thin film or cause a side reaction with the precursor or reactant, so it is recommended to use a substance having a purity of 99% or higher if possible.

[0114] The above reformed gas can be transported into the chamber by the VFC method, the DLI method, or the LDS method.

[0115] The ratio of the precursor material and the modified gas injected into the chamber (mg / cycle) can be 1:1 to 1:20, and in this case, an ultra-thin film can be provided while maintaining film density.

[0116] The above-mentioned modifying gas has an injection (supply) time (sec) on the substrate of preferably 0.01 to 10 seconds per cycle, more preferably 0.02 to 8 seconds, even more preferably 0.04 to 6 seconds, and even more preferably 0.05 to 4 seconds, and within this range, there is an advantage of improved initial film formation rate, excellent step coverage, and excellent economy.

[0117] The above feeding time is based on a flow rate of 0.1 to 8,000 mg / cycle at a chamber volume of 15 to 20 L, and more specifically, based on a flow rate of 10 to 5,000 mg / cycle at a chamber volume of 18 L.

[0118] The halogen compound provided as the above-described reforming gas may be included in a thin film formed through the deposition step described below at a level of 100 ppm or less. If the halogen remains excessively, for example, when using the nitriding agent described below under temperature conditions of 200 to 300°C, chlorides such as NH4I are generated and remain in the thin film, which is undesirable.

[0119] The above thin film can be used for purposes such as a wiring metal film, a low-resistance metal film, etc., but is not limited thereto.

[0120] In particular, since the initial film formation rate is greatly reduced while forming a relatively thick film, uniformity is secured even when applied to a substrate with a complex structure, and deposition is possible with a particularly thin thickness, and it can provide the effect of improving the amount of O, Si, metal, metal oxide remaining as process byproducts, and even carbon residue that was difficult to reduce in the past.

[0121]

[0122] The above deposition step can deposit a thin film made of a barrier material and / or a high-k dielectric material on the substrate by injecting a reaction gas that reacts with the source gas.

[0123] The above deposition step can be performed by spraying a reaction gas onto the substrate. Through the adsorption step, modification step, and deposition step, a thin film can be formed on the substrate using an atomic layer deposition (ALD) method.

[0124] The above deposition step can be performed by spraying ozone (O3), oxygen (O2), nitrogen (N2), or ammonia (NH3) as a reaction gas onto the substrate.

[0125] The amount of the reaction gas may be, for example, 10 to 10,000 times the volume of the precursor material introduced into the chamber, preferably 50 to 50,000 times, and more preferably 100 to 10,000 times, and within this range, the oxidation-reduction reaction can be effectively performed to form a thin film evenly and prevent deterioration of the film quality.

[0126] The above reaction gas can be preferably transported into the ALD chamber by the VFC method, the DLI method or the LDS method, and more preferably, it is transported into the chamber by the VFC method.

[0127]

[0128] By depositing a barrier material and / or a high-k dielectric material through the above modification step to manufacture a thin film, the ultra-thin film forming method according to the present invention can provide the following effects.

[0129] First, in the case of the comparative example manufactured as a thin film made of a barrier material and / or a high-k material without the above-mentioned modification step, the ultra-thin film forming method according to the present invention not only makes the thin film made of a barrier material and / or a high-k material, but is also modified to improve the initial reactivity of deposition, thereby manufacturing a thin film with further reduced current leakage or further improved current characteristics even though it is formed with a thinner thickness than the thin film according to the comparative example. Therefore, the ultra-thin film forming method according to the present invention can contribute to manufacturing a semiconductor device with a finer and thinner thickness.

[0130] Second, the ultra-thin film formation method according to the present invention, by including the above-described modification step, can simultaneously provide densification and uniformity effects that increase film density while forming a thin film using a barrier material and / or a high-k material. The use of a modification gas induces a material with low bonding strength into a material with high bonding strength, thereby enabling the production of a thin film with improved quality through film densification, impurity removal, and other improvements.

[0131] Third, since the ultra-thin film formation method according to the present invention includes the above-described modification step, the redox reaction required for effective deposition of the precursor adsorbed on the substrate can be effectively performed at a relatively low process temperature at which the precursor is not thermally decomposed, and the initial film formation rate can be appropriately increased to significantly improve film uniformity and produce a thin film with low resistance even when deposited on a substrate having a highly integrated or complex structure.

[0132]

[0133] The above ultra-thin film forming method may include a first purge step, a second purge step, and a third purge step.

[0134] The above first purge step can be performed by spraying a purge gas onto the substrate after the adsorption step is performed.

[0135] The above modification step may be performed after the above first purge step is performed.

[0136] The second purge step can be performed by spraying purge gas onto the substrate after the modification step is performed.

[0137] The deposition step may be performed after the second purge step is performed.

[0138] The third purge step can be performed by spraying a purge gas onto the substrate after the deposition step is performed.

[0139] The purge gas used in each of the first purge step, the second purge step, and the third purge step may be an inert gas such as argon or nitrogen, for example.

[0140] The above purge gas is not particularly limited as long as it is an amount sufficient to remove the unabsorbed substance (gas), but for example, it may be 10 to 10,000 times, preferably 50 to 50,000 times, and more preferably 100 to 10,000 times, based on the volume of the precursor material injected into the chamber, and within this range, the unabsorbed substance (gas) can be sufficiently removed so that a thin film can be formed evenly and deterioration of the film quality can be prevented. Here, the amounts of the purge gas and the precursor material injected are each based on one cycle, and the volume of the precursor material means the volume of the vapor of the precursor material injected.

[0141] Each purge step can be performed at, for example, 1,000 to 50,000 sccm (Standard Cubic Centimeter per Minute), more preferably 2,000 to 30,000 sccm, and even more preferably 2,500 to 15,000 sccm, and within this range, the initial film formation rate per cycle is appropriately controlled, and deposition is performed as or close to a single atomic mono-layer, which is advantageous in terms of film quality.

[0142]

[0143] The entire steps described above (adsorption step, first purge step, modification step, second purge step, deposition step, third purge step) can be repeated as a unit cycle until an ultra-thin film of the desired thickness is obtained, and when the modification gas is sequentially introduced with the precursor material within one cycle to improve the film quality, the generated process byproducts are effectively removed, thereby reducing the resistivity, greatly improving the step coverage, improving the uniformity while improving the film quality such as electrical characteristics and density, and providing a thin film with low resistance.

[0144] The chamber may be an ALD chamber, a CVD chamber, a PEALD chamber, or a PECVD chamber.

[0145] The substrate loaded into the chamber may be heated to 100 to 600°C.

[0146] The reaction temperature of the above overall steps (adsorption step, first purge step, modification step, second purge step, deposition step, third purge step) may be, for example, 100 to 600°C.

[0147] The above precursor material or modifying gas may include a step of vaporizing and then injecting and then plasma post-processing, in which case the initial film formation rate can be improved while reducing process byproducts.

[0148] The substrate loaded in the chamber can be heated, for example, to 100 to 700°C, specifically, to 300 to 600°C, and the modifying gas or precursor material can be injected onto the substrate in an unheated or heated state, and depending on the deposition efficiency, it is possible to first inject the material in an unheated state and then adjust the heating conditions during the deposition process. For example, it can be injected onto the substrate at 50 to 400°C for 1 to 20 seconds.

[0149] The ratio of the precursor material and the modified gas injected into the chamber (mg / cycle) may be preferably 1:1 to 1:400, more preferably 1:2 to 1:350, still more preferably 1:2 to 1:300, and still more preferably 1:2.5 to 1:200, and within this range, the effect of improving the step coverage and reducing the process by-products is significant.

[0150] The above ultra-thin film forming method, for example, when using the precursor material and the modifying gas, can have a deposition rate increase rate represented by the following mathematical expression 1 of 25% or more, and specifically, 30% or more, and in this case, there is an advantage in that film properties such as electrical characteristics and density can be improved and a thin film with low resistance can be provided.

[0151] [Mathematical Formula 1]

[0152] Deposition rate increase rate = [{(DR i )-(DR f )} / (DR i )]×100

[0153] (In the above formula, DR (Deposition rate, Å / cycle) is the rate at which an ultra-thin film is deposited. In the deposition of an ultra-thin film formed with a precursor and a modifying gas, DR i (initial deposition rate) is the deposition rate of an ultra-thin film formed without injecting a modifying gas. DR f (Final deposition rate) is the deposition rate of the ultra-thin film formed by injecting a modifying gas when performing the above process. Here, the deposition rate (DR) is a value measured under room temperature and pressure conditions using an ellipsometer device for an ultra-thin film with a thickness of 10 nm or less, or 5 nm or less, and is expressed in Å / cycle.)

[0154] In the above mathematical expression 1, the ultra-thin film growth rate per cycle when using and not using the modifying gas means the ultra-thin film deposition thickness (Å / cycle) per cycle, i.e., the deposition rate, and the deposition rate can be obtained by measuring the final thickness of an ultra-thin film having a thickness of 10 nm or less or a thickness of 5 nm or less under room temperature and pressure conditions using an ellipsometer, for example, and then dividing it by the total number of cycles to obtain the average deposition rate.

[0155] In the above mathematical expression 1, “when no modifying gas is used” means a case where a thin film is manufactured by adsorbing only a precursor compound on a substrate in an ultra-thin film deposition process, and as a specific example, it refers to a case where a thin film is formed by omitting the step of adsorbing a modifying gas and the step of purging unadsorbed modifying gas in the above ultra-thin film formation method.

[0156] The above ultra-thin film formation method can be performed at a deposition temperature in the range of, for example, 100 to 600°C, preferably at a deposition temperature in the range of 300 to 500°C, and more preferably at a deposition temperature in the range of 300 to 400°C, and has the effect of growing an excellent film quality while providing ALD process characteristics within this range.

[0157] The above ultra-thin film formation method can be performed at a deposition pressure in the range of, for example, 0.01 to 20 Torr, preferably at a deposition pressure in the range of 0.1 to 20 Torr, more preferably at a deposition pressure in the range of 0.1 to 10 Torr, and most preferably at a deposition pressure in the range of 0.3 to 7 Torr, and has the effect of obtaining an ultra-thin film of uniform thickness within this range.

[0158] In this description, the deposition temperature and deposition pressure can be measured as the temperature and pressure formed within the deposition chamber, or as the temperature and pressure applied to the substrate within the deposition chamber.

[0159] The above ultra-thin film forming method may preferably include a step of raising the temperature inside the chamber to a deposition temperature before introducing the precursor material into the chamber; and / or a step of purging the chamber by injecting an inert gas into the chamber before introducing the precursor material into the chamber.

[0160] The above ultra-thin film forming method is such that the intensity (c / s) of residual impurities (carbon or halogen elements) in the ultra-thin film based on the ultra-thin film thickness of 100 Å, as measured by SIMS, may be preferably 100,000 or less, more preferably 70,000 or less, even more preferably 50,000 or less, and even more preferably 10,000 or less, and in a preferred embodiment, 5,000 or less, more preferably 10 to 4,000, and even more preferably 10 to 3,000, and within this range, the effect of preventing deterioration of crystallinity and electrical characteristics is excellent.

[0161]

[0162] Additionally, the above modification step may be performed prior to the adsorption step if necessary.

[0163] That is, a method for forming an ultra-thin film can be provided, comprising: a modification step of forming a modified material on a substrate by injecting a modification gas; an adsorption step of forming an adsorbent material on the substrate by injecting a source gas composed of at least one material selected from a barrier material and a high-k material onto the substrate; and a deposition step of depositing a thin film composed of at least one material selected from a barrier material and a high-k material onto the substrate by injecting a reaction gas that reacts with the adsorbent material. When the adsorption step, the modification step, and the deposition step are performed as one cycle, a thin film formed when repeating 10 cycles has a thickness of 10 Å or less, and a thin film formed when repeating 20 cycles has a thickness of 20 Å or less at the same time.

[0164]

[0165] In addition, the present invention can provide a method for forming an ultra-thin film, characterized in that it uses a compound having a bond dissociation energy between a central metal atom and a ligand of less than 350 kJ / mol, calculated using a Gaussian 16 program (DFT-D3 / B3LYP basis set (central metal, iodine: LanL2DZ, C, N, O, H, X: 6-31+G(dp))) to modify a surface or adsorbed source.

[0166]

[0167] In addition, the present invention may include a manufacturing device capable of performing the above ultra-thin film forming method, including an ALD chamber, a first vaporizer for vaporizing a precursor material, a first transfer means for transferring the vaporized precursor material into the ALD chamber, a second vaporizer for vaporizing a modifying gas, a second transfer means for transferring the vaporized modifying gas into the ALD chamber, and a third transfer means for transferring a reaction gas into the ALD chamber.

[0168] Here, the vaporizer and the transport means are not particularly limited as long as they are vaporizers and transport means commonly used in the technical field to which the present invention belongs.

[0169] As a specific example, regarding the above ultra-thin film formation method, first, a substrate on which a thin film is to be formed is placed in a deposition chamber capable of atomic layer deposition.

[0170] The above substrate may include a semiconductor substrate such as a silicon substrate or silicon oxide.

[0171] The above substrate may further have a conductive layer or an insulating layer formed on top thereof.

[0172] In order to deposit a thin film on a substrate positioned in the above deposition chamber, the above-described modifying gas, precursor material, or mixture thereof with a non-polar solvent are each prepared.

[0173] Afterwards, the prepared modified gas, precursor material, or mixture thereof with a non-polar solvent is injected into the vaporizer, changed into a vapor phase, and transferred to the deposition chamber to be adsorbed on the substrate, and unadsorbed material (gas) is removed through each purge step.

[0174] The above non-polar solvent may preferably be at least one selected from the group consisting of alkanes and cycloalkanes, and in this case, there is an advantage in that the step coverage is improved even when the deposition temperature is increased during the formation of an ultra-thin film while containing an organic solvent that has low reactivity and solubility and is easy to manage moisture.

[0175] As a more preferred example, the non-polar solvent may include a C1 to C10 alkane or a C3 to C10 cycloalkane, preferably a C3 to C10 cycloalkane, in which case it has the advantages of low reactivity and solubility and easy moisture management.

[0176] In this description, C1, C3, etc. refer to the number of carbon atoms.

[0177] The above cycloalkane may preferably be a C3 to C10 monocycloalkane, and among the above monocycloalkanes, cyclopentane is liquid at room temperature and has the highest vapor pressure, so it is preferred in a vapor deposition process, but is not limited thereto.

[0178] The above nonpolar solvent has, for example, a solubility in water (25°C) of 200 mg / L or less, preferably 50 to 400 mg / L, more preferably 135 to 175 mg / L, and within this range has the advantage of low reactivity toward the precursor material and easy moisture management.

[0179] In this description, solubility is not particularly limited if it is measured using a measurement method or standard commonly used in the technical field to which the present invention belongs, and for example, a saturated solution can be measured using the HPLC method.

[0180] The non-polar solvent may preferably comprise 5 to 95 wt%, more preferably 10 to 90 wt%, even more preferably 40 to 90 wt%, and most preferably 70 to 90 wt%, based on the total weight of the precursor material and the non-polar solvent.

[0181] If the content of the nonpolar solvent is added in excess of the upper limit, impurities are generated, which increases resistance and film impurity levels. If the content of the organic solvent is added in excess of the lower limit, there is a disadvantage in that the effect of improving step coverage due to solvent addition and the effect of reducing impurities such as chloride (Cl) ions are small.

[0182]

[0183] As described above, the ultra-thin film forming method comprises, for example, a step of sequentially injecting a precursor material and the modifying gas into a chamber to adsorb them onto the substrate surface, and a step of purging the unadsorbed material as a unit cycle, and the unit cycle can be repeated to form an ultra-thin film of a desired thickness.

[0184] The above unit cycle can be repeated, for example, 1 to 99,999 times, preferably 10 to 1,000 times, more preferably 50 to 5,000 times, and even more preferably 100 to 2,000 times, and within this range, there is an effect of well expressing the desired membrane characteristics.

[0185]

[0186] The present invention also provides a semiconductor substrate, characterized in that the semiconductor substrate is manufactured by the ultra-thin film forming method of the present invention, and in this case, the film thickness uniformity is greatly excellent and the density and electrical characteristics are excellent.

[0187] The above ultra-thin film may have a thickness of, for example, 10 nm or less, for another example, 5 nm or less, for a specific example, 0.001 to 5 nm, and preferably 0.01 to 1.5 nm, and within this range, it has an excellent effect of providing an ultra-thin film having an extremely thin film thickness while having excellent barrier properties or high dielectric properties.

[0188] The above ultra-thin film may have a resistivity value of, for example, 0.1 to 1,000 μΩ·cm, preferably 0.1 to 900 μΩ·cm, and more preferably 0.1 to 800 μΩ·cm based on an ultra-thin film thickness of 1.5 nm, and has excellent film properties within this range.

[0189] The above ultra-thin film may preferably have an impurity content of 10,000 ppm or less, or 1 to 9,000 ppm, more preferably 1 to 8,500 ppm, and even more preferably 1 to 1,000 ppm, and within this range, the film crystallinity is excellent while the resistivity is improved. Here, the impurities remaining in the ultra-thin film are impurities remaining due to insufficient reduction of the metal precursor ligand, and may be, for example, carbon, nitrogen, oxygen, or halogen elements, and the lower the impurity residue in the ultra-thin film, the better the film quality is, which is preferable.

[0190] The above ultra-thin film is characterized in that the content of ligand-derived film impurities, such as carbon, is reduced to 1% or less when measured by XPS.

[0191] The above ultra-thin film is characterized in that the maximum etching height from the top to the bottom (substrate side) of the thin film, as measured by an atomic force microscope (AFM) after immersion in hydrofluoric acid (HF, 1% dilution) for 5 minutes, is 50% or less by etching evaluation, and thus no pin holes are generated in the thin film even after etching treatment.

[0192] The above ultra-thin film is characterized in that the maximum etching height from the top to the bottom (substrate side) of the thin film measured by an atomic force microscope (AFM) after immersion in hydrofluoric acid (HF, 1% dilution) for 5 minutes is 1.5 nm or less by etching evaluation, and no pin holes are generated in the thin film even after etching treatment.

[0193]

[0194] Unless otherwise stated herein, percentages are by weight.

[0195] The above ultra-thin film has, for example, a step coverage of 90% or more, preferably 92% or more, and more preferably 95% or more, and within this range, even a complex structure can be easily deposited on a substrate, so it has the advantage of being applicable to next-generation semiconductor devices.

[0196] The above-mentioned manufactured ultra-thin film preferably has a thickness of 1.5 nm or less, and has an impurity content of carbon, nitrogen, oxygen, halogen, etc. of 10,000 ppm or less based on the ultra-thin film thickness of 1.5 nm, and a step coverage of 90% or more, and has excellent performance as a barrier, dielectric, or blocking film within this range, but is not limited thereto.

[0197] The above ultra-thin film is characterized by improved crystallinity as measured by XRD.

[0198] The above ultra-thin film is characterized by improved resistivity.

[0199]

[0200] Hereinafter, an embodiment of a thin film according to the present invention will be described in detail.

[0201] The thin film according to the present invention can be manufactured through the ultra-thin film forming method according to the present invention described above.

[0202] The thin film according to the present invention may include a thin film layer formed on a substrate.

[0203] The above thin film layer can be formed on the substrate using a mixture containing a barrier material or a high-k material.

[0204] The above thin film layer can be provided as a thin film having a thickness of 10 Å / 10 cycles or less and 20 Å / 10 cycles or less as measured using TEM, and a surface roughness of 0.3 nm or less as measured using Tilted SEM after immersion in hydrofluoric acid (HF, 1% diluted solution) for 5 minutes. Accordingly, the thin film according to the present invention is formed with a thin thickness, but has a dielectric constant capable of reducing current leakage or is implemented to improve electrical characteristics, and thus can contribute to manufacturing semiconductor devices with finer and thinner thicknesses.

[0205] The above thin film layer was deposited on the substrate through the above adsorption step, the above modification step, and the above deposition step.

[0206] The above thin film layer includes a thin film formed on a substrate using at least one material selected from among a barrier material and a high-k material, and the thin film has a thickness measured using TEM of 10 Å / 10 cycles or less and 20 Å / 10 cycles or less, and a surface roughness measured using Tilted SEM of 0.3 nm or less after immersion in hydrofluoric acid (HF, 1% dilution) for 5 minutes.

[0207] The above thin film is at least one selected from a titanium nitride film, a tantalum nitride film, a ruthenium film, an aluminum oxide film, a calcium oxide film, a yttrium oxide film, a strontium oxide film, a zirconium oxide film, a hafnium oxide film, a tantalum oxide film, a lanthanum oxide film, a barium oxide, and a titanium oxide film.

[0208] The above ultra-thin film was immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes and etched. As measured by an atomic force microscope (AFM), the maximum etching height from the top to the bottom (substrate side) of the thin film was 50% or less, confirming that no pinholes were created.

[0209] The above ultra-thin film was immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes and the maximum etching height from the top to the bottom (substrate side) of the thin film measured using an atomic force microscope (AFM) was confirmed to be 1.5 nm or less, indicating that no pinholes were created.

[0210] In this case, the thin film according to the present invention is implemented to have resistance or dielectric constant for use as an electrode or dielectric film when compared to a thin film that does not include a modification step, and thus forms a dense and uniform thin film of thinner thickness, thereby improving the quality of the ultra-thin film and securing various applications.

[0211] The above-described thin film layer is formed of a barrier material and / or a high-k material, and may be modified using a modifying gas. Modification using a modifying gas removes impurities within the thin film, and materials with low bonding strength can have their bonds broken, leaving only materials with high bonding strength. Accordingly, the thin film according to the present invention can have a thinner thickness while exhibiting improved quality through film densification, crystallization, and impurity removal.

[0212] Two specific experimental examples are disclosed below, but these are only examples and are not limiting.

[0213]

[0214] Example 1

[0215] As a specific example, the ultra-thin film formation process was performed as follows using 5N HI as a reforming gas and TiCl4 as a precursor material.

[0216] That is, the prepared precursor material was placed in a separate canister and supplied to a separate vaporizer heated to 150°C at a flow rate of 0.1 g / min using a Liquid Mass Flow Controller (LMFC) at room temperature. The TiCl4 precursor vaporized in the vaporizer was introduced into the deposition chamber for 3 seconds, and then argon gas was supplied at 5000 sccm for 10 seconds to perform argon purging. At this time, the pressure inside the reaction chamber was controlled at 2.5 Torr.

[0217] Next, the prepared reforming gas was placed in a canister and supplied to the chamber at a flow rate of 1000 sccm using a mass flow controller (MFC) at room temperature. The reforming gas, vaporized in a vapor phase from the vaporizer, was injected into the deposition chamber loaded with the substrate for 2 seconds to perform a reduction reaction, and then argon gas was supplied at 5000 sccm for 10 seconds to perform argon purging. At this time, the pressure inside the reaction chamber was controlled at 2.5 Torr.

[0218] Next, NH3 as the prepared reaction gas was supplied to the chamber at a flow rate of 1,000 sccm. The reaction gas vaporized in a vapor phase from the vaporizer was introduced into the deposition chamber loaded with the substrate for 2 seconds to perform a reduction reaction, and then argon gas was supplied at 5,000 sccm for 10 seconds to perform argon purging. At this time, the pressure inside the reaction chamber was controlled at 2.5 Torr.

[0219] The above deposition temperature was maintained at 500°C, and this process was repeated 10 to 400 times to form an atomic layer thin film.

[0220]

[0221] The film thickness, resistivity, and surface roughness of the manufactured ultra-thin film (TiN film) were measured for each deposition cycle, and the results are shown in Table 1 below.

[0222] Specifically, the thickness of the ultra-thin film (TiN film) was measured using a transmission electron microscope (TEM), and as shown in Fig. 1 below, it was satisfied with about 10 Å / 10 cycles or less and about 20 Å / 10 cycles or less.

[0223] For reference, the following Figure 1 is a graph comparing the thickness of a thin film formed between an example according to the present invention and a comparative example according to the prior art, and the thickness of a thin film formed per deposition cycle is also shown in the following Figure 2 by changing the variables.

[0224] For reference, the following Figure 3 is a scanning electron microscope (SEM) photograph showing the etching evaluation results after immersion in hydrofluoric acid (HF, 1% dilution) for 5 minutes as an etching evaluation result between an example according to the present invention and a comparative example according to the prior art.

[0225] Furthermore, the surface roughness of the manufactured ultra-thin film (TiN film) measured by AFM according to the immersion time of 1 minute, 5 minutes, and 10 minutes before immersion in hydrofluoric acid (HF, 1% dilution) was calculated to be less than 0.3 nm, as shown in Fig. 4 below.

[0226] In addition, the ultra-thin film was immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes and the maximum etching height from the top to the bottom (substrate side) of the film measured using an atomic force microscope (AFM) was observed to be 50% or less.

[0227] In addition, the ultra-thin film was immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes and the maximum etching height from the top to the bottom (substrate side) of the film was observed to be 1.5 nm or less as measured by an atomic force microscope (AFM) through an etching evaluation.

[0228] Furthermore, as a result of measuring the deposition rate increase rate (GPC) using the following mathematical formula 1, an improvement of more than 30% was confirmed.

[0229] [Mathematical Formula 1]

[0230] Deposition rate increase rate = [{(DR i )-(DR f )} / (DR i )]×100

[0231] (In the above formula, DR (Deposition rate, Å / cycle) is the rate at which an ultra-thin film is deposited. In the deposition of an ultra-thin film formed with a precursor and a modifying gas, DR i (initial deposition rate) is the deposition rate of an ultra-thin film formed without injecting a modifying gas. DR f (Final deposition rate) is the deposition rate of the ultra-thin film formed by injecting a modifying gas when performing the above process. Here, the deposition rate (DR) is a value measured under room temperature and pressure conditions using an ellipsometer device for an ultra-thin film with a thickness of 10 nm or less, or 5 nm or less, and is expressed in Å / cycle.)

[0232] Ultra-thin film former-TiN @ 500 ℃ (Example 1)ALD cycle61117224365117160Thickness (Å)8101520365795130Resistivity (μΩ·cm)Not measurableNot measurableNot measurableNot measurable7781969271Surface roughness (nm)2.43.54.03.03.57.76.0

[0233] (The non-measurable values ​​in the table above are those where the resistivity is too large to be recorded by the equipment.)

[0234] Comparative Example 1

[0235] The same process was repeated except that the reforming step of injecting reformed gas in Example 1 was omitted, and the same measurement results as in Example 1 described above are shown in Table 2 below.

[0236] The thickness of the metal film deposited per cycle was calculated by dividing the film thickness measured by an ellipsometer, which is a device that can measure optical properties such as the thickness or refractive index of a metal film using the polarization characteristics of light, by the number of cycles, and the results were 6 Å / 10 cycles or less and 10 Å / 10 cycles or less, confirming a poor initial film formation rate that falls short of the ultra-thin films of Examples 1 and 2.

[0237] In addition, the sheet resistance of the manufactured ultra-thin film (TiN film) was measured using the 4-probe measurement method, and the measured thickness was used to calculate the resistivity value.

[0238] Furthermore, the surface roughness of the manufactured ultra-thin film (TiN film) measured by AFM after immersion in hydrofluoric acid (HF, 1% dilution) over time increased with the immersion time, as shown in Fig. 4 below, and was calculated to be over 0.4 nm after immersion for 10 minutes, confirming that it was inferior to Example 1.

[0239] In addition, the ultra-thin film was immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes and the maximum etching height from the top to the bottom (substrate side) of the film was observed to be more than 90% as measured by an atomic force microscope (AFM) through an etching evaluation.

[0240] In addition, the ultra-thin film was immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes and the maximum etching height from the top to the bottom (substrate side) of the film was observed to be more than 1.5 nm as measured by scanning electron microscopy (SEM) and atomic force microscopy (AFM) through etching evaluation.

[0241] Furthermore, as a result of measuring the deposition rate increase rate (GPC) using the aforementioned mathematical expression 1, it was confirmed that the value was significantly less than 30%.

[0242] Ref. TiN @ 500 ℃ (Comparative Example 1) ALD cycle 10 20 30 45 90 150 250 Thickness (Å) 5 10 20 28 48 67 118 Resistivity (μΩ cm) Not measurable Not measurable Not measurable Not measurable 5 0 6 5 2 9 5 161 Surface roughness (nm) 4.1 4.8 6.2 5.5 6.3 8.2

[0243] (The non-measurable values ​​in the table above are those where the resistivity is too large to be recorded by the equipment.)

[0244] As shown in Tables 1 and 2 above, according to the present invention, the thickness per deposition cycle is very high, the critical thickness at which resistivity is measured is relatively low, and the surface roughness is improved. This is because a flat thin film is formed at a lower thickness.

[0245]

[0246] Example 2

[0247] The same process as in Example 1 was repeated except that the reformed gas was introduced prior to the adsorption step.

[0248] The thickness of the metal film deposited per cycle was calculated by dividing the film thickness measured by TEM for the manufactured ultra-thin film (TiN film) by the number of cycles, and the results were found to be 10 Å / 10 cycles or less and 20 Å / 10 cycles or less.

[0249] In addition, the sheet resistance of the manufactured ultra-thin film (TiN film) was measured using the 4-probe measurement method, and the measured thickness was used to calculate the resistivity value.

[0250] Furthermore, the manufactured ultra-thin film (TiN film) was immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes and measured using a tilted SEM, confirming the absence of pin-holes.

[0251] In addition, the ultra-thin film was immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes and the maximum etching height from the top to the bottom (substrate side) of the film measured using an atomic force microscope (AFM) was observed to be 50% or less.

[0252] In addition, the ultra-thin film was immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes and the maximum etching height from the top to the bottom (substrate side) of the film was observed to be 1.5 nm or less as measured by an atomic force microscope (AFM) through an etching evaluation.

[0253] Furthermore, as a result of measuring the deposition rate increase rate (GPC) using the aforementioned mathematical expression 1, it was confirmed that the value significantly exceeded 30%.

[0254]

[0255] As can be seen from the results of the above Examples 1 and 2, unlike Comparative Example 1 according to the prior art, when a unique modified gas is used for a precursor material having a predetermined bond dissociation energy, the thickness measured using TEM satisfies 10 Å / 10 cycles or less and 20 Å / 10 cycles or less, thereby increasing the initial film formation rate, and at the same time, it was confirmed that a densified, uniform ultra-thin film without pinholes is provided, such as a surface roughness measured using Tilted SEM of 0.3 nm or less after immersion in hydrofluoric acid (HF, 1% dilution) for 5 minutes.

[0256] Furthermore, it was confirmed that not only was the resistivity improved, but the impurities remaining within the thin film were also reduced.

[0257] In addition to the above TiN (titanium nitride film), it was 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 also provide ultra-thin films with film densification and uniformity, and furthermore, it was confirmed that not only was the resistivity improved, but also the impurities remaining in the thin film were reduced.

[0258] The above-mentioned 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 were also immersed in hydrofluoric acid (HF, 1% dilution) for 5 minutes and the maximum etching height from the top to the bottom (substrate side) of the thin film measured with an atomic force microscope (AFM) was 50% or less, and at the same time, the maximum etching height from the top to the bottom (substrate side) of the thin film measured with an atomic force microscope (AFM) was 1.5 nm or less, respectively, through the etching evaluation after immersing in hydrofluoric acid (HF, 1% dilution).

[0259]

[0260] In detail, the results of calculating the bond dissociation energy of carbon or hydrogen compounds combined with iodine in the reformed gases represented by the chemical formulas 1-1 to 1-12 are shown in Table 3 below.

[0261]

[0262] Furthermore, as a computer simulation verification experiment, the energy value of the transition structure was calculated by optimizing it with Gaussian 16 program (DFT-D3 / B3LYP basis set (central metal, iodine, chlorine: LanL2DZ, C, N, O, H, Si: 6-31+G(dp)), TS (Berny).

[0263] Specifically, the structure of the adsorbed form with the MoCl5 precursor was optimized by using the SiO2 cluster (Si9H12-(OH)2) model as a substrate, and the activation energy required for each reaction with H2 and HI was calculated, and a schematic diagram based on the measurement results is shown in Table 2 below.

[0264] The activation energy value calculated by the above computer simulation was defined as the minimum energy (Ea) required for the precursor material to proceed from the state of chemical adsorption on the substrate (Ads) to the product (final) reaction path, i.e., the energy difference to the activated state (TS), and the energy of each state was calculated and confirmed.

[0265] Table 2 below shows the results of evaluating the deposition rate, average resistivity, and resistivity change compared to the unused Comparative Example 1 according to the bond dissociation energy of the materials used to reduce the reaction activation energy between TiCl4 and NH3 reaction gases during the formation of a TiN thin film.

[0266]

[0267] As shown in Table 4 above, it was confirmed that the range of resistivity degradation increases as the carbon and iodine bond dissociation energy increases.

[0268]

[0269] As a result, it was confirmed that the method is suitable for improving film quality such as electrical characteristics, crystallinity, etc., by including a modification step using a predetermined modification gas to deposit a precursor material having a specific bond dissociation energy in providing an ultra-thin film from a barrier material and / or a high-k material, thereby improving film density and film uniformity together with the initial film formation rate, thereby preventing and inhibiting the inflow of thin film impurities caused by ligands such as carbon and preventing the generation of pinholes during etching evaluation.

Claims

1. A thin film formed on a substrate using at least one material selected from among a barrier material and a high-dielectric constant material, The above thin film has a thickness of 10 nm or less as measured using TEM, The above thin film is an ultra-thin film characterized by having a root mean square surface roughness of 0.3 nm or less.

2. A thin film formed on a substrate using at least one material selected from among a barrier material and a high-k material, and having a thickness of 5 nm or less as measured using TEM, An ultra-thin film characterized by a deposition rate increase of more than 30% by utilizing a modified gas.

3. In paragraph 1 or 2, The above thin film is an ultra-thin film characterized by having a surface roughness of 0.3 nm or less as measured by an atomic force microscope (AFM) after immersion in hydrofluoric acid (HF, 1% dilution) for 5 minutes.

4. In paragraph 1 or 2, The above thin film is an ultra-thin film characterized in that it is at least one selected from a titanium nitride film, a tantalum nitride film, a ruthenium, an aluminum oxide film, a calcium oxide film, a yttrium oxide film, a strontium oxide film, a zirconium oxide film, a hafnium oxide film, a tantalum oxide film, a lanthanum oxide film, a barium oxide, and a titanium oxide film.

5. In paragraph 1 or 2, The above thin film is an ultra-thin film characterized in that the maximum etching height from the top to the bottom (substrate side) of the thin film, as measured by an atomic force microscope (AFM) after immersion in hydrofluoric acid (HF, 1% dilution) for 5 minutes, is 50% or less.

6. In paragraph 1 or 2, The above thin film is an ultra-thin film characterized in that the maximum etching height from the top to the bottom (substrate side) of the thin film, as measured by an atomic force microscope (AFM) after immersion in hydrofluoric acid (HF, 1% dilution) for 5 minutes, is 1.5 nm or less.

7. An adsorption step of forming an adsorption material on a substrate by spraying a source gas composed of at least one material selected from among a barrier material and a high-dielectric constant material; A modification step of modifying an adsorbent material formed on the substrate by injecting a modification gas that reacts with the source gas; and A deposition step of depositing a thin film made of at least one material selected from a barrier material and a high-dielectric constant material on the substrate by injecting a reaction gas that reacts with the above-mentioned reforming gas; An ultra-thin film forming method characterized in that, when the above adsorption step, modification step, and deposition step are performed as one cycle, the thickness of the thin film formed when repeating 10 cycles is 10 Å or less, and the thickness of the thin film formed when repeating 20 cycles is 20 Å or less at the same time.

8. A modification step for modifying the surface by spraying a modification gas on the substrate surface and causing an adsorption reaction with the source gas on the substrate; and An adsorption step of forming an adsorption material on a substrate by spraying a source gas composed of at least one material selected from among a barrier material and a high-dielectric constant material; A deposition step of depositing a thin film made of at least one material selected from among a barrier material and a high-k dielectric material on the substrate by injecting a reaction gas that reacts with the source gas; An ultra-thin film forming method characterized in that, when the above modification step, adsorption step, and deposition step are performed as one cycle, the thickness of the thin film formed when repeating 10 cycles is 10 Å or less, and the thickness of the thin film formed when repeating 20 cycles is 20 Å or less at the same time.

9. In paragraph 7 or 8, The above adsorption step is a method for forming an ultra-thin film, characterized in that the source gas is at least one 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).

10. In paragraph 7 or 8, The above modification step is a method for forming an ultra-thin film, characterized in that it sprays a halogen gas containing iodine and having a weight average molecular weight of 127 to 250 g / mol onto the substrate.

11. In paragraph 10, A method for forming an ultra-thin film, characterized in that the above-mentioned reforming gas includes a substance having a direct bond between hydrogen (H) and iodine, a substance having a direct bond between carbon (C) and iodine, or a substance having a direct bond between a halogen element (F, Cl, Br) and iodine.

12. In paragraph 11, A method for forming an ultra-thin film, characterized in that the material having a direct bond between hydrogen (H) and iodine has a total binding energy of 305 to 325 kJ / mol calculated using the basis set of the Gaussian 16 program (DFT-D3 / B3LYP (iodine: LanL2DZ, carbon, hydrogen element: 6-31+G(dp)).

13. In paragraph 11, A method for forming an ultra-thin film, characterized in that the material having a direct bond between the carbon (C) and iodine exhibits a three-dimensional structure and the total binding energy of the compound is 165 to 242 kJ / mol, calculated using the basis set (iodine: LanL2DZ, carbon, hydrogen element: 6-31+G(dp)) of the Gaussian 16 program (DFT-D3 / B3LYP).

14. In paragraph 11, A method for forming an ultra-thin film, characterized in that the total binding energy of the compound calculated using the basis set (iodine: LanL2DZ, carbon, hydrogen element: 6-31+G(dp)) of the Gaussian 16 program (DFT-D3 / B3LYP) of the substance having a direct bond between the halogen element (F, Cl, Br) and iodine is 50 to 160 kJ / mol.

15. In paragraph 7 or 8, The above deposition step is a method for forming an ultra-thin film, characterized in that ozone (O3), oxygen (O2), nitrogen (N2), or ammonia (NH3) is sprayed as a reaction gas onto the substrate.

16. In paragraph 7 or 8, A first purge step of spraying purge gas onto the substrate after the above adsorption step is performed; A second purge step of spraying purge gas onto the substrate after the above modification step is performed; and A method for forming an ultra-thin film, characterized in that it comprises a third purge step of spraying a purge gas onto the substrate after the above deposition step is performed.

17. A method for forming an ultra-thin film, characterized in that the method uses a compound having a bond dissociation energy between a central metal atom and a ligand of less than 350 kJ / mol, calculated using the Gaussian 16 program (DFT-D3 / B3LYP basis set (central metal, iodine: LanL2DZ, C, N, O, H, X: 6-31+G(dp))) to modify a surface or adsorbed source.

18. A semiconductor substrate characterized by including the ultra-thin film of claim 1 or 2.

19. A semiconductor device characterized by including a semiconductor substrate according to claim 18.

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