KR102700990B1 - Activator, method for preparing depostiion films, semiconductor and semiconductor device prepared thereof - Google Patents

Abstract

The present invention relates to an activator, a semiconductor substrate manufactured using the same, and a semiconductor device. The method for manufacturing a titanium-containing deposition film of the present invention has the effect of easily manufacturing a high-purity deposition film through a simple process by using a titanium-based precursor compound and a specific reaction gas.

Description

ACTIVATOR, METHOD FOR PREPARING DEPOSTIION FILMS, SEMICONDUCTOR AND SEMICONDUCTOR DEVICE PREPARED THEREOF

The present invention relates to an activator, a semiconductor substrate and a semiconductor device manufactured using the same, and more particularly, to an activator which provides a compound including a halogen different from a halogen ligand included in a precursor compound as an activator, thereby improving the reactivity with a subsequently injected reactant through replacement with a halogen ligand in the precursor compound, thereby improving a deposition reaction rate and greatly improving the density and resistivity of a deposition film, and greatly reducing impurities, and to a semiconductor substrate and a semiconductor device manufactured using the same.

The ideal ALD (atomic layer deposition) process is based on a self-limiting reaction, where the ligands of the precursors adsorbed on the substrate prevent the deposition of the subsequently injected precursors. However, in the actual process, the precursors undergo thermal history, which may include some thermal decomposition in which the ligands are detached from the central metal. This process has the characteristics of a type of CVD (chemical vapor deposition), and the greater this characteristic, the lower the step-coverage, density, and thickness uniformity of the deposited film. In addition, there is a problem that the detached ligand species may remain as impurities in the deposited film if they are well adsorbed to the surface as F, Cl, etc., or if they easily form fluorides or chlorides. (Refer to J. Phys. Chem. B. 13491-8, “Surface chemistry in the atomic layer deposition of TiN films from TiCl4 and ammonia” (2006))

The density and thickness uniformity of the above-mentioned deposition film are factors that affect the electrical and chemical characteristics. For example, electrical conductivity may be reduced, and by-products (such as HCl) derived from the leaving group of the halogen ligand may be absorbed to contaminate the deposition film or disrupt the crystal arrangement of the deposition film, thereby further lowering the density.

Therefore, it is important to reduce the thermal history of the precursor so that the process can be performed in the atomic layer deposition (ALD window). However, generally, the higher the deposition temperature, the better the film quality can be obtained. For example, when depositing a titanium nitride thin film, the thin film deposited at a higher temperature exhibits lower resistivity. In order to implement a thin film with low resistivity even when the deposition temperature is lowered, the first ligand of the precursor adsorbed on the substrate based on the self-limiting reaction is changed to a second ligand with higher reactivity to react with a reactant, enabling the formation of a deposition film with a complex structure, and improving the thickness uniformity and deposition reaction speed of the deposition film, as well as lowering the amount of residual impurities and greatly improving the density to improve electrical characteristics such as resistivity, and a method for manufacturing a deposition film utilizing the same, and semiconductor substrates and semiconductor devices manufactured thereby are required.

In order to solve the problems of the prior art as described above, the present invention aims to provide an activator which improves electrical characteristics by providing a compound of a predetermined structure as a second ligand to change the first ligand of a precursor compound, thereby greatly improving the deposition reaction speed, the thickness uniformity and density of a deposition film, and a semiconductor substrate and semiconductor device manufactured using the same.

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

To achieve the above object, the present invention provides an activator including an alkyl free halide for changing the ligand of a precursor compound bonded to a group 4 central metal.

Additionally, the present invention provides an activator comprising an alkyl free halide for filling a ligand leaving site of a precursor compound bonded to a Group 4 central metal.

When the precursor compound contains a halogen, and the halogen is referred to as a first halogen, the halogen constituting the alkyl-free halide may be a second halogen different from the first halogen.

The above first halogen may be selected from at least one of fluorine, chlorine, iodine, and bromine.

The above second halogen may be selected from at least one of iodine and bromine.

The above alkyl-free halide can form an intermediate for providing a deposited film in which a reactant-derived material is bonded to the Group 4 metal.

The above reactant-derived material can be provided from H2O, H2O2, O2, O3, O radical, D2, H2, H radical, NH3, NO2, N2O, N2, N radical, H2S or S.

The above intermediate may refer to a state in which the first ligand of the precursor compound is replaced by a compound having a predetermined structure as a second ligand.

The above group 4 central metal may be titanium.

The above alkyl-free halide can be an alkyl-free iodine donor, hydrogen iodide gas, hydrogen bromide gas, iodine ion or iodine radical.

The above deposition may be atomic layer deposition (ALD), plasma enhanced atomic layer deposition (PEALD), chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), metalorganic chemical vapor deposition (MOCVD), or low pressure chemical vapor deposition (LPCVD).

In addition, the present invention provides a semiconductor substrate in which, when the precursor adsorption state before ligand exchange on the substrate is -M-Xn (n= 1 to 3, X= F, Cl), the precursor adsorption state after ligand exchange is -M-Ym (m= 1 to 3, Y= Br, I).

The change in the precursor adsorption state before and after the ligand exchange can be formed by a reaction between a precursor compound in which a first halogen is bonded to a Group 4 central metal on the substrate; and an alkyl free halide including a second halogen for filling a ligand leaving site of the precursor compound described above.

The above semiconductor substrate may include a deposition film formed through a process in which a first halogen atom (F or Cl) in the central metal (M) of the above chemical formula 1 is replaced with a second halogen atom (Br or I).

The above deposition film may include a structure represented by the following chemical formula 2.

[Chemical formula 2]

M _a H _d

(In the above chemical formula 1, M is a group 4 metal, H is at least one of O, N, and S, a is an integer of 1, and d is 0 to 2.2.)

The composition of the above deposition film can be confirmed through XPS analysis.

The above deposition film may be a multilayer structure of two or more layers, a multilayer structure of three or more layers, or a multilayer structure of two or three layers.

The above deposition film may have a deposition thickness of 500 Å or less as measured by an ellipsometer.

The above-mentioned deposition film may have a resistivity of 300 μΩ.cm or less.

The density of the above deposition film may be 4.5 g/cm3 or more.

The above-mentioned deposition film can have an iodine atom count of 50 counts/s or more as measured by SIMS.

The above deposition film is an oxide film, a nitride film, a metal film or a sulfide film, and may be used as a diffusion barrier film, an etching stop film, an electrode film, a dielectric film, a gate insulating film, a block oxide film or a charge trap.

In addition, the present invention provides a semiconductor device including the semiconductor substrate described above.

According to the present invention, there is an activation effect of improving the reaction deposition reaction rate by changing the leaving group of the precursor adsorbed on the substrate to a second halogen, and appropriately increasing the thickness uniformity and density of the deposition film, thereby improving the productivity of the deposition film.

In addition, when forming a deposition film, process byproducts are reduced more effectively along with improved density, thereby preventing corrosion or deterioration and improving the crystallinity of the deposition film, thereby improving the electrical properties of the deposition film.

In addition, it is possible to improve the thickness uniformity of the deposition film, and further has the effect of providing a method for manufacturing a deposition film using the same, and a semiconductor substrate and semiconductor device manufactured thereby.

Figure 1 is a drawing comparing the deposition thickness and resistivity measured in eight types of deposition films of Example 1 using an activator according to the present invention and ten types of deposition films of Comparative Example 1 not using an activator.
Figure 2 is a drawing comparing the contents of process by-products and impurities (Cl, O, Si, H, NH, metals, metal oxides) measured by SIMS in Comparative Example 1 where no activator was used.
FIG. 3 is a drawing comparing the contents of process by-products and impurities (Cl, O, Si, H, NH, metals, metal oxides) measured by SIMS in Example 1 using an activator according to the present invention.

Below, the activator of the present invention, the semiconductor substrate and semiconductor device manufactured using the same are described in detail.

The present inventors have confirmed that by providing a predetermined compound as an activator capable of changing a ligand released from a precursor compound used to form a deposition film on the surface of a substrate loaded inside a chamber, the deposition reaction rate can be improved, the thickness uniformity of the deposition film can be secured, and the density and resistivity of the deposition film can be greatly improved, and Cl, O, Si, H, NH, metals, metal oxides, etc. remaining as process byproducts can be reduced. Based on this, the inventors have devoted themselves to research on activators and completed the present invention.

Below, we will specifically examine a semiconductor substrate and a semiconductor device including an activator and a deposition film manufactured using the same.

Activator

The above activator may be a predetermined compound capable of changing a ligand to be released as a deposition additive compound used to better form a deposition film on the surface of a substrate loaded inside a chamber in the present invention.

The above precursor compound may be, for example, a compound in which a halogen is bonded to a group 4 central metal, and thus, during injection onto a substrate to form a deposition film, a ligand leaving site is formed in which a significant portion of the halogen is removed.

In the case where the activator used in the present invention is an alkyl free halide, it can appropriately perform the role of filling the ligand leaving site.

The above term “alkyl free”, unless otherwise specified, refers to not only not containing an alkyl group, but also not containing an alkene group or an alkyne group.

When the halogen constituting the above precursor compound is referred to as a first halogen, the halogen constituting the alkyl-free halide may be a second halogen different from the first halogen.

The above first halogen may be selected from at least one of fluorine, chlorine, iodine, and bromine.

The above second halogen may be selected from at least one of iodine and bromine.

The above activator 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. As a reference, if a compound having a purity of less than 99% is used, impurities may remain in the deposition 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.

The above activator preferably has a density of 1.0 to 4.0 g/cm ³ or 2.0 to 3.4 g/cm ³ and a vapor pressure of 1 atm at 180 to 240 K, and within this range has excellent effects in improving step coverage, thickness uniformity of the deposited film, resistivity, and film quality.

The above alkyl-free halide can form an intermediate for providing a deposition film having a structure in which a reactant-derived material is bonded to the Group 4 metal.

Here, the reactant-derived substance can be provided from H2O, H2O2, O2, O3, O radical, D2, H2, H radical, NH3, NO2, N2O, N2, N radical, H2S or S.

The above alkyl-free halide is characterized by being at least one selected from an alkyl-free iodine donor, hydrogen iodide gas, hydrogen bromide gas, iodine ion, or iodine radical, and in this case, by suppressing side reactions and controlling the growth rate of the deposition film, process by-products in the deposition film are reduced, corrosion or deterioration is reduced, the crystallinity of the deposition film is improved, and a stoichiometric oxidation state is reached when a metal oxide film is formed, and even when the deposition film is formed on a substrate having a complex structure, there is an effect of significantly improving the step coverage and the thickness uniformity of the deposition film.

As a specific example, the activator is a single hydrogen iodide having a purity of 3N to 15N, a gas mixture comprising 1 to 99 wt% of hydrogen iodide having a purity of 3N to 15N and the remainder of an inert gas so that the total amount becomes 100 wt%, or an aqueous solution mixture comprising 0.5 to 70 wt% of hydrogen iodide having a purity of 3N to 15N and the remainder of water so that the total amount becomes 100 wt%, wherein the inert gas is nitrogen, helium or argon having a purity of 4N to 9N, in which case the effect of reducing process by-products is large, the step covering property is excellent, the effect of improving the density of the deposited film and the electrical characteristics of the deposited film can be more excellent.

Preferably, the activator is a gas mixture of hydrogen iodide alone of 3N to 7N, hydrogen iodide of 1 to 99 wt% and an inert gas balance such that the total amount becomes 100 wt%, or an aqueous solution mixture of hydrogen iodide of 0.5 to 70 wt% and water balance such 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, when the deposition film is formed, a substitution region which does not remain in the deposition film is formed, thereby forming a relatively thick deposition film while suppressing side reactions and controlling the deposition film growth rate, so that process by-products in the deposition film are reduced, corrosion or deterioration is reduced, the crystallinity of the deposition film is improved, and even when the deposition film is formed on a substrate having a complex structure, step coverage and thickness uniformity of the deposition film can be significantly improved.

In the present invention, the activator or precursor compound may include a step of vaporizing and then injecting and then performing a plasma post-treatment, in which case the growth rate of the deposition film can be improved while reducing process by-products.

The above deposition may be atomic layer deposition (ALD), plasma enhanced atomic layer deposition (PEALD), chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), metalorganic chemical vapor deposition (MOCVD), or low pressure chemical vapor deposition (LPCVD).

Precursor compound

In the present invention, the precursor compound used to form a deposition film is a molecule having a Group 4 metal as a central metal atom (M) and at least one ligand composed of C, N, O, H, and X (halogen), and in the case of a precursor having a vapor pressure of 1 mTorr to 100 Torr at 25° C., the effect of filling a leaving site with an activator described below can be maximized.

As an example, the precursor compound may be a compound represented by the following chemical formula 1.

[Chemical Formula 1]

(In the above chemical formula 1, M is a quaternary metal, L1, L2, L3 and L4 may be the same or different as -H, -X, -R, -OR, or -NR2 and contain at least one -X, wherein -X is F, Cl, or Br, and -R is a C1-C10 alkyl, a C1-C10 alkene, or a C1-C10 alkane, which may be linear or cyclic.)

In the chemical formula 1 above, M is titanium (Ti), and in this case, there are advantages such as a large effect of reducing process by-products, excellent step coverage, an effect of improving the density of the deposited film , and superior electrical and insulating properties of the deposited film.

In the above chemical formula 1, L1, L2, L3 and L4 may be the same or different as -H or -X and include at least one -X, wherein -X may be F, Cl, or Br.

In addition, as an example, the titanium precursor compound may have a structure represented by the following chemical formula 1-1, or a structure represented by the following chemical formula 1-2.

[Chemical Formula 1-1]

The above L1 can be H, F, Cl, Br, Me, Et, iPr, OMe, OEt, NMe ₂ , NEt ₂ , or NMeEt.

The above L2 can be H, F, Cl, Br, Me, Et, iPr, OMe, OEt, NMe ₂ , NEt ₂ , or NMeEt.

The above L3 can be H, F, Cl, Br, Me, Et, iPr, OMe, OEt, NMe ₂ , NEt ₂ , or NMeEt.

The above L4 can be H, F, Cl, Br, Me, Et, iPr, OMe, OEt, NMe ₂ , NEt ₂ , or NMeEt.

The above L1 to L4 may be the same or different.

Unless otherwise stated in this description, Me represents a methyl group and Et represents an ethyl group.

The structure represented by the chemical formula 1-1 above may be, for example, TiCl ₄ , TiBr ₄ , Ti(OMe) ₄ , or Ti(NMe ₂ ) ₄ .

[Chemical Formula 1-2]

The above L', L”, and L”’ can independently be OMe, OEt, NMe2, NEt2, or NMeEt.

The above R can be Me or Et.

n can be an integer from 0 to 5.

Compounds represented by the chemical formula 1-2 above include, for example, CpMeTi(OMe) ₃ , CpMe ₂ Ti(OMe) ₃ , CpMe ₃ Ti(OMe) ₃ , CpMe ₄ Ti(OMe) ₃ , CpMe ₅ Ti(OMe) ₃ , CpMeTi(OEt) ₃ , CpMe ₂ Ti(OEt) ₃ , CpMe ₃ Ti(OEt) ₃ , CpMe ₄ Ti(OEt) ₃ , CpMe ₅ Ti(OEt) ₃ , CpMeTi(NMe ₂ ) ₃ , CpMe ₂ Ti(NMe ₂ ) ₃ , CpMe ₃ Ti(NMe ₂ ) ₃ , CpMe ₄ Ti(NMe ₂ ) ₃ , CpMe ₅ Ti(NMe ₂ ) ₃ , CpMeTi(NEt ₂ ) ₃ , CpMe ₂ Ti(NEt ₂ ) ₃ , CpMe ₃ Ti(NEt ₂ ) ₃ , CpMe ₄ Ti( _{NEt 2 ) 3} , CpMe ₅ Ti ₍ NMeEt) ₃ , CpMe ₂ Ti(NMeEt) ₃ , CpMe ₃ Ti(NMeEt) ₃ , CpMe Ti(NMe ₄ It may be Et) ₃ , or CpMe ₅ Ti(NMeEt) ₃ .

In the present invention, the precursor compound can be introduced into the chamber by mixing it with, for example, a non-polar solvent, and in this case, there is an advantage in that the viscosity or vapor pressure of the precursor compound can be easily controlled.

The above nonpolar 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 increases during the formation of the deposition film while containing an organic solvent that has low reactivity and solubility and easy moisture management.

As a more preferred example, the nonpolar solvent may include a C1 to C10 alkane or a C3 to C10 cycloalkane, preferably a C3 to C10 cycloalkane, in which case there are advantages of low reactivity and solubility and easy moisture management.

In this description, C1, C3, etc. indicate the number of carbon atoms.

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

The above nonpolar solvent has, for example, a solubility in water (at 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 compound and easy moisture management.

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.

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 compound and the non-polar solvent.

If the content of the nonpolar solvent is added in excess of the upper limit, it causes impurities, which increases the resistance and the impurity level in the deposition film, and if the content of the organic solvent is added in less than the lower limit, there are disadvantages in that the effect of improving the step coverage due to the addition of the solvent and the effect of reducing impurities such as chlorine (Cl) ions are small.

Deposition film

It includes a deposition film obtained using the above-mentioned activator.

The above deposition film may have a multilayer structure of two or more layers.

For example, the deposition film may include a structure in which a reactant-derived material and a second halogen are combined with a Group 4 metal.

The above-mentioned deposition film may have a deposition thickness measured by SIMS of 170 Å or less, or 100 to 170 Å.

The resistivity of the above-mentioned deposition film may be 300 μΩ.cm or less, or 150 to 300 μΩ.cm, and the electrical conductivity may be improved within the above range.

The deposition rate of the above-mentioned deposition film may be 0.34 Å/cycle or more, or 0.34 to 0.535 Å/cycle.

The density of the above-mentioned deposition film may be 4.8 g/cm3 or more, or 4.8 to 5.3 g/cm3.

The above deposition film can have a deposition rate increase rate represented by the following mathematical expression 1 of 10% or more, specifically 12.5% or more, preferably 15% or more, and in this case, the growth rate of the deposition film formed at the same time as the deposition film is formed by the activator having the above-described structure is greatly reduced, so that even when applied to a substrate having a complex structure, the uniformity of the deposition film is secured, the step coverage is greatly improved, and in particular, it can provide the effect of improving the O, Si, metal, metal oxide remaining as process byproducts, and even the carbon residue which was not easy to reduce in the past.

[Mathematical Formula 1]

Sedimentation rate increase rate = [(DR _f )/(DR _i )]×100

(In the above equation, DR (Deposition rate, Å/cycle) is the rate at which the deposition film is deposited. In the deposition of the deposition film formed with the precursor and the reactant, DR _i (initial deposition rate) is the deposition rate of the deposition film formed without adding an activator. DR _f (final deposition rate) is the deposition rate of the deposition film formed by adding an activator when performing the same process as above. Here, the deposition rate (DR) is a value measured under room temperature and pressure conditions using an ellipsometer device for a deposition film having a thickness of 1 to 30 nm, and uses the unit of Å/cycle.)

In the above mathematical expression 1, the deposition film growth rate per cycle when an activator was used and when not used means the deposition film deposition thickness (Å/cycle) per cycle, i.e., the deposition rate, and the deposition rate can be obtained as an average deposition rate by measuring the final thickness of a deposition film having a thickness of 1 to 30 nm under room temperature and pressure conditions using an ellipsometer, for example, and dividing the measurement by the total number of cycles.

In the above mathematical expression 1, “when an activator is not used” means a case where a deposition film is manufactured by adsorbing only a precursor compound on a substrate in a deposition film deposition process, and as a specific example, it refers to a case where a deposition film is formed by omitting the step of adsorbing an activator and the step of purging the unadsorbed activator in the deposition film forming method.

The above-mentioned deposition film can provide a metal film, an oxide film, a nitride film, a sulfide film or a chalcogenide, and in this case, the effect intended to be achieved in the present invention can be sufficiently obtained.

The above deposition film may include the above-described film composition alone or as a selective area, but is not limited thereto, and also includes SiH and SiOH.

The above-mentioned deposition film can be utilized in semiconductor devices not only as a generally used diffusion barrier film, but also as an etching stop film, electrode film, dielectric film, gate insulating film, block oxide film, or charge trap.

The above-mentioned deposition film can contain halogen compounds at a rate of 10,500 counts/s or less, as measured using SIMS, for example.

Method for manufacturing a deposition film

The above deposition film can be manufactured by various methods, and for example, can be manufactured by the following methods:

As a first step, a precursor compound including a Group 4 metal and a first halogen can be injected onto a substrate loaded in a chamber.

The above first halogen may be selected from, for example, one or more of fluorine, chlorine, iodine, and bromine, and it is preferable to include chlorine, which has excellent reactivity.

In the present invention, the method for delivering the precursor compound to the deposition chamber may include, for example, a method for delivering volatilized gas by using a mass flow controller (MFC) method, a method for controlling the flow rate of a liquid (Mass Flow Controller; MFC), a method for delivering a liquid (Liquid Delivery System; LDS), and a method for controlling the flow rate of a liquid (Mass Flow Controller; MFC).

At this time, as a carrier gas or dilution gas for moving the precursor compound onto the substrate, one or more mixed gases selected from the group consisting of argon (Ar), nitrogen (N ₂ ), and helium (He) may be used, but is not limited thereto.

In the present invention, an inert gas may be used as the purge gas, for example, and preferably, the carrier gas or dilution gas may be used.

The chamber may be an atomic layer deposition (ALD) chamber, a plasma enhanced atomic layer deposition (PEALD) chamber, a chemical vapor deposition (CVD) chamber, a plasma enhanced chemical vapor deposition (PECVD) chamber, a metalorganic chemical vapor deposition (MOCVD) chamber, or a low pressure chemical vapor deposition (LPCVD) chamber.

The substrate loaded into the chamber may include a semiconductor substrate such as a silicon substrate or silicon oxide.

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

The above substrate can be maintained at 50 to 500°C, or 80 to 500°C.

The above substrate can be heated to, for example, 50 to 500° C., specifically, 80 to 500° C., 100 to 800° C., or 200 to 500° C., and the activator or precursor compound can be injected onto the substrate in an unheated or heated state, and depending on the deposition efficiency, it may be injected in an unheated state and then the heating conditions may be adjusted during the deposition process. For example, it can be injected onto a substrate heated to 300 to 600° C. for 1 to 20 seconds.

The amount of precursor compound injected into the chamber (mg/cycle) is, for example, a ratio of the amount of precursor compound injected into the chamber (mg/cycle) to the activator used in the second step described below, of 1:1 to 1:20, preferably 1:1 to 1:15, more preferably 1:1 to 1:10, and within this range, the effect of improving the step coverage and reducing process by-products is significant.

The above first step may include one or more purging steps using an inert gas. The inert gas may be the carrier gas or dilution gas described above.

In the step of purging the non-absorbed precursor compound, the amount of the purge gas injected into the chamber is not particularly limited as long as it is an amount sufficient to remove the non-absorbed precursor compound. However, for example, it may be 10 to 100,000 times the volume of the precursor compound injected into the chamber, preferably 50 to 50,000 times, and more preferably 100 to 10,000 times, and within this range, the non-absorbed precursor compound can be sufficiently removed so that the deposition film is formed evenly and deterioration of the film quality can be prevented. Here, the injection amounts of the purge gas and the precursor compound are each based on one cycle, and the volume of the precursor compound means the volume of the vapor of the precursor compound.

In the present invention, purging is preferably 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. Within this range, the deposition film growth 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.

In the second step, an alkyl-free halide containing a second halogen different from the first halogen is injected into the substrate to change the leaving site of the first halogen to the second halogen. In this case, the leaving group of the precursor adsorbed on the substrate is effectively changed to improve the reaction rate, and the deposition film growth rate is appropriately lowered, so that even when a deposition film is formed on a substrate having a complex structure, the step coverage, resistivity, and thickness uniformity of the deposition film are significantly improved.

The above second halogen may be selected from, for example, at least one of iodine and bromine, and it is preferable to use iodine.

The supply time (Feeding Time, sec) of the activator to the substrate surface is preferably 0.001 to 10 seconds per cycle, more preferably 0.02 to 3 seconds, even more preferably 0.04 to 2 seconds, and even more preferably 0.05 to 1 second, and within this range, there are advantages of a high deposition film growth rate, excellent step coverage, and excellent cost efficiency.

In this description, the feeding time of the activator is based on a flow rate of 1 to 500 sccm at a chamber volume of 15 to 20 L, and more specifically, on a flow rate of 10 to 200 sccm at a chamber volume of 18 L.

In this invention, the method of delivering the activator to the deposition chamber may be, for example, a method of transporting volatilized gas by using a mass flow controller (MFC) method (vapor flow control; VFC).

The second step may include one or more purging steps using an inert gas. In the present disclosure, the carrier gas or dilution gas may be used as the purge gas, for example.

In the present invention, purging is preferably 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. Within this range, the deposition film growth 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.

In the step of purging the non-absorbed activator, the amount of purge gas injected into the chamber is not particularly limited as long as it is an amount sufficient to remove the non-absorbed activator. However, for example, it may be 10 to 100,000 times, preferably 50 to 50,000 times, and more preferably 100 to 10,000 times, and within this range, the non-absorbed activator can be sufficiently removed so that the deposition film is evenly formed and deterioration of the film quality can be prevented. Here, the injected amounts of the purge gas and the activator are each based on one cycle, and the volume of the activator means the volume of the vapor of the activator that has been exposed.

As a specific example, when the activator is injected at a flow rate of 100 sccm and an injection time of 0.5 sec (per cycle) and, in the step of purging the unabsorbed activator, a purge gas is injected at a flow rate of 3000 sccm and an injection time of 5 sec (per cycle), the injection amount of the purge gas is 300 times the injection amount of the activator.

Next, as a third step, a reactant can be injected into the substrate to form a deposition film derived from a group 4 metal.

The above reactant may be a gas including, for example, H2O, H2O2, O2, O3, O radical, D2, H2, H radical, NH3, NO2, N2O, N2, N radical, H2S or S.

The above deposition film may include a structure in which a reactant-derived material and a second halogen are combined with a Group 4 metal.

The above deposition film formation method can be performed at a deposition temperature in the range of, for example, 50 to 800°C, preferably at a deposition temperature in the range of 100 to 700°C, more preferably at a deposition temperature in the range of 200 to 650°C, and even more preferably at a deposition temperature in the range of 220 to 500°C, and has the effect of growing a deposition film of excellent film quality while implementing process characteristics within this range.

The above deposition 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 within this range, there is an effect of obtaining a deposition film of uniform thickness.

In this disclosure, 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.

The second step may further include a step of raising the temperature inside the chamber to a deposition temperature, preferably before injecting the activator into the chamber; and/or a step of purging by injecting an inert gas into the chamber before injecting the activator into the chamber.

The third step may include a purging step using an inert gas.

In the purging step performed immediately after the above reaction gas supply step, the amount of purge gas injected into the chamber may be, for example, 10 to 10,000 times the volume of the reaction gas injected into the chamber, preferably 50 to 50,000 times, and more preferably 100 to 10,000 times, and the desired effect can be sufficiently obtained within this range. Here, the injection amounts of the purge gas and the reaction gas are each based on one cycle.

In the present invention, purging is preferably 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. Within this range, the deposition film growth 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.

The above deposition film forming method can be repeated 1 to 99,999 times as needed for a unit cycle, preferably 10 to 10,000 times, more preferably 50 to 5,000 times, and even more preferably 100 to 2,000 times, and within this range, the desired thickness of the deposition film can be obtained while sufficiently obtaining the effect to be achieved in the present invention.

As a specific example of the above deposition film manufacturing method, in order to deposit a deposition film on a substrate positioned in the chamber, the above-described activator and a precursor compound or a mixture thereof and a non-polar solvent are each prepared.

Thereafter, the prepared precursor compound or a mixture thereof and a non-polar solvent is injected into a vaporizer, changed into a vapor phase, and transferred to a deposition chamber to be adsorbed onto a substrate, and the ligand of the precursor compound is replaced by a pre-injected activator, and the unadsorbed precursor compound is purged.

Next, the prepared activator is injected into the vaporizer, changed into a vapor phase, transferred to the deposition chamber, adsorbed onto the substrate, and purged to remove any unadsorbed activator.

In the present invention, the method for delivering the activator and precursor compounds to the deposition chamber may include, for example, a method for delivering volatilized gas (Vapor Flow Control; VFC) by utilizing a mass flow controller (MFC) method, or a method for delivering liquid (Liquid Delivery System; LDS) by utilizing a liquid mass flow controller (LMFC) method.

At this time, as a carrier gas or dilution gas for moving the activator and precursor compound, etc. onto the substrate, one or more mixed gases selected from the group consisting of argon (Ar), nitrogen (N ₂ ), and helium (He) may be used, but is not limited thereto.

In the present disclosure, an inert gas may be used as the purge gas, for example, and preferably, the carrier gas or dilution gas may be used.

Next, a reactant is supplied. The reactant is not particularly limited as long as it is a reaction gas commonly used in the technical field to which the present invention belongs, and may preferably include a nitriding agent. The nitriding agent reacts with the precursor compound adsorbed on the substrate to form a nitride film.

Preferably, the nitriding agent may be nitrogen gas (N ₂ ), hydrazine gas (N ₂ H ₄ ), or a mixture of nitrogen gas and hydrogen gas.

Next, the unreacted residual reaction gas is purged using an inert gas. Accordingly, not only the excess reaction gas but also the generated byproducts can be removed.

As described above, the method for forming the deposition film comprises, as an example, a step of adsorbing a precursor compound onto a substrate, a step of purging the unabsorbed precursor compound, a step of supplying an activator onto the substrate, a step of purging the unabsorbed activator, a step of supplying a reaction gas, and a step of purging the residual reaction gas, and the unit cycle can be repeated to form a deposition film of a desired thickness.

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 in which the desired deposition film characteristics are well expressed.

When the injection time and purge time of the precursor compound in the first step are a and b, respectively, the injection time and purge time of the alkyl-free halide in the second step are c and d, respectively, and the injection time and purge time of the reactant in the third step are e and f, respectively, 0.1≤a≤10, 2a≤b≤4a, 0.1<c≤10, 2c≤d≤8c, 2<e≤10, 2e≤b≤8e can be simultaneously satisfied.

When the injection and purge of the above precursor compound and the alkyl-free halide, and the injection and purge of the reactant are considered as one cycle, the following four conditions can all be satisfied: 1) the deposition film has a deposition thickness of 500 Å or less as measured by an ellipsometer, 2) the resistivity of the deposition film is 300 μΩ.cm or less, 3) the deposition rate is 0.34 Å/cycle or more, and 4) the density of the deposition film is 4.5 g/cm3 or more.

The above-mentioned deposition film may have a deposition thickness measured by an ellipsometer of 500 Å or less, or 2 to 300 Å, and more preferably 5 to 250 Å.

The above-mentioned deposition film may have a resistivity of 300 μΩ.cm or less, or 10 to 300 μΩ.cm, and more preferably 30 to 200 μΩ.cm.

The density of the above-mentioned deposition film may be 4.5 g/cm3 or more, or 4.5 to 5.5 g/cm3.

The above-mentioned deposition film can have an iodine atom count of 50 counts/s or more as measured by SIMS.

When the injection and purge of the above precursor compound and the alkyl-free halide, and the injection and purge of the reactant are considered as one cycle, the following four conditions can all be satisfied: 1) the deposition film has a deposition thickness of 100 to 500 Å as measured by an ellipsometer, 2) the resistivity of the deposition film is 150 to 300 μΩ.cm, 3) the deposition rate is 0.34 to 0.535 Å/cycle, and 4) the density of the deposition film is 4.8 to 5.5 g/cm3.

The above deposition film manufacturing method can be performed using a deposition film manufacturing apparatus including, for example, an ALD chamber, a first vaporizer for vaporizing an activator, a first transfer means for transferring the vaporized activator into the ALD chamber, a second vaporizer for vaporizing a deposition film precursor, and a second transfer means for transferring the vaporized deposition film precursor into the ALD chamber. Here, the vaporizer and the transfer means are not particularly limited as long as they are vaporizers and transfer means commonly used in the technical field to which the present invention belongs.

semiconductor substrate

The present invention also provides a semiconductor substrate, characterized in that the semiconductor substrate is manufactured by the deposition film forming method of the present invention or includes the deposition film, in which case the step coverage of the deposition film and the thickness uniformity of the deposition film are significantly excellent, and the density and electrical characteristics of the deposition film are excellent.

As a specific example, a semiconductor substrate according to the present invention can provide a semiconductor substrate in which, when the precursor adsorption state before ligand exchange on the substrate is -M-Xn (n= 1 to 3, X= F, Cl), the precursor adsorption state after ligand exchange is -M-Ym (m= 1 to 3, Y= Br, I).

The change in the precursor adsorption state before and after the ligand exchange can be formed by a reaction between a precursor compound in which a first halogen is bonded to a Group 4 central metal on the substrate; and an alkyl free halide including a second halogen for filling a ligand leaving site of the precursor compound described above.

For example, the semiconductor substrate may include a deposition film formed through a process in which a first halogen atom (F or Cl) in the central metal (M) of the chemical formula 1 is replaced with a second halogen atom (Br or I).

The above-mentioned deposition film may be, for example, a multilayer structure of two or more layers, a multilayer structure of three or more layers, or a multilayer structure of two or three layers, as needed. The multilayer film having a two-layer structure may be, for example, a lower layer film-middle layer film structure, and the multilayer film having a three-layer structure may be, for example, a lower layer film-middle layer film-upper layer film structure.

The above-mentioned deposition film may be, for example, a middle film (TiN electrode for DRAM or barrier film for NAND).

The above lower layer may be formed by including at least one selected from the group consisting of, for example, Si, SiO ₂ , MgO, Al ₂ O ₃ , CaO, ZrSiO ₄ , ZrO ₂ , HfSiO ₄ , Y ₂ O ₃ , HfO ₂ , LaLuO ₂ , Si ₃ N ₄ , SrO, La ₂ O ₃ , Ta ₂ O ₅ , BaO, and TiO ₂ .

The above upper layer may be formed by including at least one selected from the group consisting of, for example, W and Mo.

semiconductor devices

According to the present invention, a semiconductor device including the above-described semiconductor substrate can be provided.

The semiconductor device may be, for example, low resistive metal gate interconnects, high aspect ratio 3D metal-insulator-metal (MIM) capacitors, DRAM trench capacitors, 3D Gate-All-Around (GAA), or 3D NAND flash memory.

Hereinafter, preferred embodiments and drawings are presented to help understand the present invention. However, the following embodiments and drawings are only illustrative of the present invention, and it is obvious to those skilled in the art that various changes and modifications are possible within the scope and technical idea of the present invention, and it is also natural that such changes and modifications fall within the scope of the appended patent claims.

[Example]

TiCl4 was prepared as a precursor compound.

5N HI was prepared as an activator.

An ALD deposition process was performed using the above precursor compound and activator with the deposition process sequence according to the present invention as one cycle.

The specific experimental methods of Example 1 and Comparative Example are as follows.

Example 1 (Examples 1-1 to 1-8)

The precursor compound TiCl4 was placed in a canister and flowed at a flow rate of 0.05 g/min using a Liquid Mass Flow Controller (LMFC) at room temperature. It was supplied to a separate vaporizer heated to 150 ℃. TiCl4 vaporized in the vaporizer was introduced into the deposition chamber using a VFC (Vapor Flow Controller) for 1 second, and then argon gas was supplied at 3000 sccm for 5 seconds to perform argon purging. At this time, the pressure inside the reaction chamber was controlled to 2.5 Torr.

Next, 5N HI as an activator was placed in a canister and supplied to a vaporizer heated to 150°C at a flow rate of 0.05 g/min using a mass flow controller (MFC) at room temperature. The activator vaporized in a vapor phase in the vaporizer was injected into the deposition chamber loaded with the substrate for 2 seconds, and then argon gas was supplied at 3000 sccm for 8 seconds to perform argon purging. At this time, the pressure inside the reaction chamber was controlled to 2.5 Torr.

Next, 1000 sccm of ammonia as a reactive gas was injected into the reaction chamber for 3 seconds, followed by argon purging for 9 seconds. At this time, the substrate on which the deposition film was to be formed was heated to 460°C.

By repeating this process 200 to 400 times, eight types of self-limiting atomic layer deposition films having the deposition thicknesses shown in Fig. 1 below were formed.

As shown in Figure 1 below, the deposition films had deposition thicknesses of 100 Å, 110 Å, 125 Å, 140 Å, 142 Å, 144 Å, 170 Å, and 175 Å, respectively.

The above deposition thickness was measured using an ellipsometer, which is a device that can measure optical properties such as the thickness or refractive index of a deposition film using the polarization characteristics of light for the manufactured deposition film.

In addition, the deposition rate increase rate (D/R (dep. rate) increase rate) was calculated for the above eight types of deposition films. Specifically, the deposition film growth rate decrease rate was calculated by dividing the thickness of the deposition film by the number of cycles to calculate the thickness of the deposition film deposited per cycle. Specifically, the calculation was performed using the mathematical expression 1 described above.

The average increase rate of the eight calculated sedimentation rates was calculated to be 0.535 Å/cycle.

In addition, the resistivity of the above eight types of deposition films was measured, and the results are shown in Figure 1 below.

The above resistivity was measured by considering the surface resistance measured by a surface resistance meter and the thickness measured by an ellipsometer.

Additionally, the resistivity values for deposition thicknesses of 100 to 130 Å were 176 Ωcm, 239 Ωcm, and 302 Ωcm, and the average was calculated to be 239 Ωcm.

Additionally, the density of the above eight types of deposition films was measured using X-ray reflectometry (XRR) equipment.

The average density of the eight measured species was calculated to be 4.68 g/cm3.

Furthermore, the impurity content of the above eight types of deposition films was measured.

Here, impurities were measured using SIMS (Secondary-ion mass spectrometry) equipment for H, C, NH, ¹⁸ O, Cl, and Ti.

Specifically, the impurity content (counts) was confirmed in the SIMS graph when the deposition film was axially penetrated by ion sputtering and the sputter time was 50 seconds, which is less contaminated with the substrate surface layer.

The verified SIMS results are shown as a graph in Fig. 2 below. Specifically, the average impurity content of Cl- in the eight types of deposition films was calculated to be 10,406 counts/s.

It can be confirmed through Figure 1 that not only Cl- but also O, Si, H, NH, metals, and metal oxides remaining as process byproducts are reduced.

Comparative Example 1

The same process as in Example 1 was repeated except that 5N HI used as an activator in Example 1 was replaced with 5N HCl.

As a result, etching occurred with increased or very thin Cl impurities.

For reference, if a plasma atmosphere of HCl or Cl2 is formed on a TiN substrate or a high temperature condition equivalent thereto is provided, there is a problem that TiN can be etched (dry etched).

Comparative Example 2

Except that 5N HI used as an activator in Example 1 was not used and a total of 10 types of deposition films were manufactured, the same process as Example 1 was repeated, and the measurement results are shown together in Figures 1 and 2 below.

As shown in Figure 1 below, the deposition films had deposition thicknesses of 88 Å, 90 Å, 100 Å, 101 Å, 102 Å, 104 Å, 109 Å, 111 Å, 121 Å, and 127 Å, respectively.

In addition, the deposition rate increase rate (D/R (dep. rate) increase rate) was calculated for the above 10 types of deposition films.

The average increase rate of sedimentation velocity of the above 10 species was calculated to be 0.34 Å/cycle.

As a result, it can be seen that it is about 30% worse than Example 1.

In addition, the resistivity of the above 10 types of deposition films was measured.

As shown in the following Figure 1, the resistivity of the deposited film was calculated to be 515 μΩcm, 517 μΩcm, 592 μΩcm, 650 μΩcm, 800 μΩcm, 802 μΩcm, 890 μΩcm, 900 μΩcm, 970 μΩcm, and 11100 μΩcm, respectively, with an average of 715 μΩcm, which can be seen to be about 50% worse than that of Example 1.

Additionally, the resistivity values for deposition thicknesses of 100 to 130 Å were 515 μΩcm, 517 μΩcm, and 592 μΩcm, and the average was calculated to be 541 μΩcm.

In addition, the density of the above 10 types of deposition films was measured using X-ray reflectometry (XRR) equipment. The measured density of the 10 types was calculated to be an average of 5.03 g/cm3, which is about 9% worse than that of Example 1.

In addition, the impurity content of the above 10 types of deposition films was measured, and the confirmed SIMS results are presented together as a graph in Fig. 2 below. Specifically, the average impurity content of Cl- in the 10 types of deposition films was calculated to be 31,638 counts/s, which can be seen to be about 50% or less inferior to that of Example 1.

From the above results, it was confirmed that Examples 1 and 2 according to the present invention using a precursor ligand and a different type of activator not only showed remarkable improvements in the deposition thickness, deposition rate increase rate, and resistivity, but also had excellent impurity reduction characteristics, compared to Comparative Example 1 using the same type of activator as the precursor ligand and Comparative Example 2 not using any activator at all.

In particular, it was confirmed that Example 1 using the activator according to the present invention was superior to Comparative Example 2 not using the activator in that the deposition rate per cycle and the density of the deposition film were each 10% or more, the resistivity reduction rate was 50% or more, and the impurity reduction rate was 60% or more.

Therefore, when a compound having a different type of ligand from that of the precursor compound is used as the activator of the present invention, it was confirmed that the thickness, deposition rate increase rate, density, and resistivity of the deposition film are all improved through the ligand exchange mechanism, and the impurity reduction characteristics are also excellent, so that the deposition film can be effectively formed even on a substrate with a complex pattern.

Claims (15)

An activator comprising an alkyl free halide for changing a ligand of a precursor compound bonded to a Group 4 central metal, wherein when a halogen included in the precursor compound is referred to as a first halogen, a halogen constituting the alkyl free halide is a second halogen different from the first halogen, and the first halogen is at least one selected from fluorine, chlorine, and bromine, and the second halogen is at least one selected from iodine and bromine. delete delete delete In the first paragraph,
An activator characterized in that the above group 4 central metal is titanium. In the first paragraph,
An activator characterized in that the above alkyl-free halide is an alkyl-free iodine donor, hydrogen iodide gas, hydrogen bromide gas, iodine ion or iodine radical. In the first paragraph,
The above activator is characterized in that it is applied to a deposition process of atomic layer deposition (ALD), plasma enhanced atomic layer deposition (PEALD), chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), metalorganic chemical vapor deposition (MOCVD), or low pressure chemical vapor deposition (LPCVD). A semiconductor substrate characterized by comprising a structure in which a ligand of a precursor compound is changed using an activator comprising an alkyl free halide of any one of claims 1, 5, to 7 on the substrate. In Article 8,
A semiconductor substrate characterized in that the structure in which the ligand of the precursor compound is changed is formed by the reaction of a precursor compound in which a first halogen is bonded to a group 4 central metal on the substrate; and an alkyl free halide including a second halogen for filling a ligand leaving site of the precursor compound. In Article 8,
A semiconductor substrate characterized in that the semiconductor substrate includes a deposition film including a structure in which a reactant-derived material and a second halogen are bonded to a quaternary central metal (M) of the precursor compound. In Article 10,
A semiconductor substrate, characterized in that the reactant-derived material is provided from H2O, H2O2, O2, O3, O radical, D2, H2, H radical, NH3, NO2, N2O, N2, N radical, H2S or S. In Article 10,
A semiconductor substrate, characterized in that the above deposition film has a multilayer structure of two or more layers. In Article 10,
A semiconductor substrate, characterized in that the above-mentioned deposition film has a deposition thickness of 500 Å or less, a resistivity of the deposition film of 300 μΩ.cm or less, a deposition rate of 0.34 Å/cycle or more, a density of the deposition film of 4.0 g/cm3 or more, and an iodine atom count of 50 counts/s or more measured by SIMS. A semiconductor device comprising a semiconductor substrate according to claim 8.
An activator comprising an alkyl free halide for changing a ligand of a precursor compound bonded to a group 4 central metal, wherein when the halogen included in the precursor compound is referred to as a first halogen, the halogen constituting the alkyl free halide is a second halogen different from the first halogen.