KR20210155136A - Precursor for high-k films, metal containing films and deposition method of the same and semiconductor device comprising the same - Google Patents

Abstract

The present invention relates to a precursor for forming a metal-containing thin film comprising a metal-containing compound represented by the following chemical formula 1 or chemical formula 2, a metal-containing thin film using the precursor, a method for forming the same, and a semiconductor including the metal-containing thin film: [chemical formula 1] [chemical formula 2]. In the formulas 1 and 2, M is any one of Ti, Zr, Hf, Si, Ge, and Sn, each L is independently a hydrogen atom, a C_1-C_6 alkyl group, OR, NHR, NRR', or CF_3, each of R and R' is independently a hydrogen atom, a C_1-C_6 alkyl group, an alkenyl group, a vinyl group, or an allyl group, and X is O or NHR. The present invention can form a thin film with a high dielectric constant by reducing a content of impurities.

Description

A precursor for forming a high dielectric constant thin film, a metal-containing thin film using the same, and a method for forming the same, and a semiconductor device including the metal-containing thin film. SAME}

The present invention relates to a precursor for forming a high-k thin film, a metal-containing thin film using the same, a method for forming the same, and a semiconductor device including the metal-containing thin film, and more particularly, to a metal-containing thin film using a low-temperature process It relates to a precursor for forming a high dielectric constant thin film capable of forming a thin film, a metal-containing thin film using the same, and a method for forming the same, and a semiconductor device including the metal-containing thin film.

Transistors that have been recently developed are becoming smaller, and the trend of technology is changing towards metal gate/high-k transistors. Accordingly, since it is difficult to secure reliability with the conventional silicon-based gate dielectric, a thin film capable of securing a larger capacitance than the conventional dielectric material is manufactured through a metal-containing thin film.

For example, in Korean Patent Laid-Open Publication Nos. 10-2019-0074855, 10-2019-0074856, and Korean Patent Publication No. 10-0754012, a high dielectric constant thin film containing a Group 4 metal such as _{ZrO 2} and HfO _{2 is formed.} To this end, a process using a metal complex containing an amine group as a precursor is being developed.

However, if the precursor according to the prior art is used, the deposition process must be performed at a relatively high temperature. In the high-temperature process, the purity according to the film crystallinity is high, but it is not suitable for the recent trend of device miniaturization and high capacity. It is necessary to enable deposition in the process. However, when the deposition is performed by a low-temperature process, there are problems such as a low film crystallinity and residual impurities, and thus it is necessary to develop a suitable precursor.

Republic of Korea Patent Publication No. 10-2019-0074855 Republic of Korea Patent Publication No. 10-2019-0074856 Republic of Korea Patent Publication No. 10-0754012

The present invention has been devised in consideration of the prior art as described above, and can increase film crystallinity due to high nucleation density through rapid adsorption even at low temperature deposition process, and reduce the content of impurities in the film through efficient discharging of ligand An object of the present invention is to provide a metal-containing precursor suitable for forming a thin film of high dielectric constant.

Another object of the present invention is to provide a process capable of forming a high dielectric constant thin film in a low-temperature process using the precursor.

Another object of the present invention is to provide a metal-containing thin film obtained by the above thin film forming step and a semiconductor device containing the thin film.

The precursor for forming a metal-containing thin film of the present invention for achieving the above object is characterized in that it includes a metal-containing compound represented by Formula 1 or Formula 2 below.

[Formula 1]

[Formula 2]

In Formulas 1 and 2, M is any one of Ti, Zr, Hf, Si, Ge, and Sn, and L is each independently a hydrogen atom, a C ₁ -C ₆ alkyl group, OR, NHR, NRR', or CF ₃ and R and R' are each independently a hydrogen atom or a C ₁ -C ₆ alkyl group, an alkenyl group, a vinyl group, or an allyl group, and X is O or NHR.

In this case, the precursor for forming the metal-containing thin film _{may include a solvent selected from tertiary amines, ethers, C 1} -C ₁₆ saturated or unsaturated hydrocarbons, and aromatic compounds, and the solvent is the precursor for forming the metal-containing thin film. It may be included in an amount of 1 to 99% by weight based on the total weight.

In addition, the metal-containing thin film according to the present invention is formed by depositing the precursor for forming the metal-containing thin film on a substrate, and the metal-containing thin film is formed by atomic layer deposition (ALD) or chemical vapor deposition (CVD). can be deposited by

In this case, the deposition may be performed at a temperature of 350° C. or less.

In addition, the semiconductor device according to the present invention is characterized in that it includes the metal-containing thin film.

When the metal-containing precursor according to the present invention is used, the film crystallinity can be increased due to high nucleation density through rapid adsorption even in the low-temperature deposition process, and the content of impurities in the film is reduced through efficient discharging of ligands to increase the high dielectric constant. A thin film can be formed.

In addition, a thin film having a high dielectric constant can be formed in a low-temperature process through the process using the precursor, and a metal-containing thin film obtained by the thin film forming process and a semiconductor device containing the thin film can be provided.

Hereinafter, the present invention will be described in more detail. The terms or words used in the present specification and claims should not be construed as being limited to their ordinary or dictionary meanings, and the inventor may properly define the concept of the term in order to best describe his invention. Based on the principle that there is, it should be interpreted as meaning and concept consistent with the technical idea of the present invention.

The precursor for forming a metal-containing thin film according to the present invention is characterized in that it includes a metal-containing compound represented by Formula 1 or Formula 2 below.

[Formula 1]

[Formula 2]

In Formulas 1 and 2, M is any one of Ti, Zr, Hf, Si, Ge, and Sn, and L is each independently a hydrogen atom, a C ₁ -C ₆ alkyl group, OR, NHR, NRR', or CF ₃ and R and R' are each independently a hydrogen atom or a C ₁ -C ₆ alkyl group, an alkenyl group, a vinyl group, or an allyl group, and X is O or NHR.

The compounds represented by Chemical Formulas 1 and 2 have a central metal atom as a Group 4 or 14 element, and when such a compound is used as a precursor, a metal thin film, an oxide thin film, a nitride thin film or an oxynitride thin film of a Group 4 or 14 element can be formed. there will be

In Chemical Formulas 1 and 2, since the functional group forms a ring structure with respect to the central metal atom, but forms a 3-membered ring or a 4-membered ring structure, stability is lower than that of a 5-membered ring or 6-membered ring structure. Due to this, it is possible to decompose at a relatively low temperature, and thus exhibits properties suitable for a low-temperature deposition process.

Since the compounds represented by Chemical Formulas 1 and 2 form a ring structure, the ring portion and the surface of the substrate are adsorbed first in the initial adsorption step, and after the initial adsorption occurs, the L site reacts with the reactant to form a film.

Therefore, in addition to the ring structure of the compound, the physical properties of the precursor may vary depending on the L site, and in the present invention, each independently a hydrogen atom, a C ₁ -C ₆ alkyl group, OR, NHR, NRR', or It can allow CF _{3 to bind.} The functional group of the L site may vary depending on the size and type of the ring structure, and the type of the functional group bonded to the ring structure.

In particular, in the case of the compound represented by Chemical Formula 2, a structure in which two nitrogen atoms are bonded to a central metal atom may be formed, but the physical properties of the precursor may be different by bonding a functional group of O or NHR to the X site. The selection of such a functional group is determined according to process conditions, the type of metal atoms to be deposited, and the type of the thin film.

In the compound represented by Formula 2, when X is NHR, the compound represented by Formula 2-1 may be formed, and when O, the compound represented by Formula 2-2 may be formed. In addition, an alkenyl group may be used instead of an alkyl group as R, and in this case, a compound represented by Formula 2-3 may be formed. In addition, although not shown, as R, a chemical structure in which an alkyl group, a vinyl group, or an allyl group is bonded may be formed.

[Formula 2-1]

[Formula 2-2]

[Formula 2-3]

That is, since the metal compound represented by Chemical Formulas 1 to 2 can be vaporized at 250° C. or less, the deposition process can be performed even at a relatively low temperature.

In addition, the metal compound may form a compound having a high viscosity or a solid state depending on the type of the functional group. In this case, a solvent may be mixed to improve the supply efficiency or to supply at a low temperature. In the case of mixing the solvent, a solvent selected from tertiary amines, ethers, C ₁ -C ₁₆ saturated or unsaturated hydrocarbons, and aromatic compounds may be used.

As the solvent, any solvent capable of dispersing or dissolving the precursor for forming the metal-containing thin film may be used. In addition, _{examples of the C 1} -C ₁₆ saturated or unsaturated hydrocarbon include pentane, heptane, octane, and toluene, and examples of the tertiary amine include dimethylethylamine and triethylamine.

The solvent may be included in an amount of 1 to 99 wt%, preferably 1 to 50 wt%, based on the total weight of the precursor for forming a metal-containing thin film. The deposition process may be performed by supplying the precursor for forming the metal-containing thin film, including or not including the solvent, into the chamber by various means.

The method of forming a thin film through the deposition process may be performed according to a method of manufacturing a thin film by a conventional deposition process on a substrate using the precursor for forming a metal-containing thin film, and specifically, chemical vapor deposition (CVD). ) or an atomic layer deposition (ALD) method. In particular, preferably, it can be prepared by an atomic layer deposition method.

The depositing may include placing a substrate in a chamber, supplying the precursor for forming the metal-containing thin film onto the substrate located in the chamber, supplying a reactive gas or plasma of the reactive gas into the chamber, in the chamber It can be carried out including the step of treating by any one or more means of heat treatment, plasma treatment, and light irradiation. In this case, the deposition process may be performed at 350° C. or less, preferably at 300° C. or less, more preferably at 250° C., and more preferably at a temperature range of 150 to 250° C. Accordingly, a relatively low temperature deposition process is possible.

In the deposition process as described above, the precursor for forming the metal-containing thin film is introduced, and in the initial chemical adsorption step, a ring opening reaction occurs at the bonding portion centered on the metal atom, through which the surface adsorption site rapidly occurs. and adsorption reactions can occur. Thereafter, a metal film, a metal oxide film, a metal nitride film, or a metal oxynitride film is formed by the reactive gas through the intermediate state.

The metal may be a central metal atom contained in the compound represented by Chemical Formula 1 or 2, specifically, a Group 4 metal atom such as titanium (Ti), zirconium (Zr), and hafnium (Hf), silicon (Si) , and group 14 metal atoms such as germanium (Ge) and tin (Sn). In addition, a thin film containing two or more types of metals may be formed by changing the types of metal atoms of the compound represented by Formula 1 or 2 above.

The substrate for forming the metal-containing thin film may be used without any particular limitation as long as it is used in semiconductor manufacturing, which needs to be coated with a metal-containing thin film due to a technical action. Specifically, a silicon substrate (Si), a silica substrate (SiO ₂ ), a silicon nitride substrate (SiN), a silicon oxynitride substrate (SiON), a titanium nitride substrate (TiN), a tantalum nitride substrate (TaN), a tungsten substrate (W) or a noble metal substrate such as a platinum substrate (Pt), a palladium substrate (Pd), a rhodium substrate (Rh), or a gold substrate (Au) may be used.

The precursor for forming the metal-containing thin film may be transferred in the form of a volatilized gas, and a direct liquid injection method or a liquid transfer method may be used. In the case of the direct liquid injection method, the metal compound represented by Chemical Formula 1 or 2 may be used as a precursor as it is, and in the case of the liquid transfer method, a precursor containing the solvent may be used. The method of transferring the precursor for forming a metal-containing thin film to a volatilized gas is a method of evaporating the precursor by placing the container containing the precursor in a thermostat and then bubbling with an inert gas such as helium, neon, argon, krypton, xenon or nitrogen. Then, it can be carried out by transferring it onto the substrate for forming the metal thin film, or by using a liquid delivery system (LDS) to change the precursor into a gas phase through a vaporizer and then transfer it onto the substrate for forming the metal thin film.

In addition, in the case of containing a solvent, the effect of reducing the viscosity and improving the volatility of the precursor for forming a metal-containing thin film is improved in consideration of the boiling point, density, and vapor pressure conditions of the solvent constituting the precursor for forming the metal-containing thin film, and through this, It is preferable to determine the solvent and the content so that a thin film having improved uniformity and step coverage characteristics of the deposited thin film can be formed.

In addition, when the precursor for forming the metal-containing thin film is supplied to the chamber, silicon (Si), titanium (Ti), germanium (Si), titanium (Ti), germanium ( A metal precursor including at least one metal selected from Ge), strontium (Sr), niobium (Nb), barium (Ba), hafnium (Hf), tantalum (Ta), and a lanthanide atom may be optionally further supplied. The second metal precursor may be an alkylamide-based compound or an alkoxy-based compound containing the metal. For example, when the metal is Si, the second metal precursor is SiH(N(CH ₃ ) ₂ ) ₃ , Si(N(C ₂ H ₅ ) ₂ ) ₄ , Si(N(C ₂ H ₅ )(CH ₃ ) ) ₄ , Si(N(CH ₃ ) ₂ ) ₄ , Si(OC ₄ H ₉ ) ₄ , Si(OC ₂ H ₅ ) ₄ , Si(OCH ₃ ) ₄ , Si(OC(CH ₃ ) ₃ ) _{4 ,} etc. this can be used

The supply of the second metal precursor may be performed in the same manner as the supply method of the precursor for forming a metal-containing thin film, and the second metal precursor may be supplied on the substrate for forming a thin film together with the precursor for forming the metal-containing thin film. Alternatively, it may be sequentially supplied after the supply of the precursor for forming the metal-containing thin film is completed.

The precursor for forming the metal-containing thin film as described above and optionally the second metal precursor are preferably maintained at a temperature of 100 to 200° C. before being supplied into the reaction chamber in order to contact the substrate for forming the metal film. In addition, it is preferable to maintain a temperature at which the precursor is not condensed by maintaining the vaporized state.

In addition, before the supply of the reactive gas after the supplying of the precursor for forming the metal-containing thin film, the precursor for forming the metal-containing thin film and optionally the second metal precursor are helped to move onto the substrate, or a pressure suitable for deposition in the reactor is applied. Also, in order to discharge impurities present in the chamber to the outside, _{a process of purging an inert gas such as argon (Ar), nitrogen (N 2} ), or helium (He) in the reactor may be performed. At this time, it is preferable that the inert gas is purged so that the pressure in the reactor is 1 to 5 Torr.

After the supply of the precursor for forming the metal-containing thin film is completed, a reactive gas is supplied into the reactor, and one type of treatment process selected from the group consisting of heat treatment, plasma treatment, and light irradiation is performed in the presence of the reactive gas.

As the reactive gas, water vapor (H ₂ O), oxygen (O ₂ ), ozone (O ₃ ), hydrogen peroxide (H ₂ O ₂ ), hydrogen (H ₂ ), ammonia (NH ₃ ), nitrogen monoxide (NO), nitrous oxide Any one of nitrogen (N ₂ O), nitrogen dioxide (NO ₂ ), hydrazine (N ₂ H ₄ ), and silane (SiH ₄ ) or a mixture thereof may be used. When carried out in the presence of an oxidizing gas such as water vapor, oxygen, ozone, etc., a thin film of oxide may be formed, and when carried out in the presence of a reducing gas such as hydrogen, ammonia, hydrazine, or silane, a thin film of a simple metal or nitride may be formed. have.

In addition, the heat treatment, plasma treatment, or the treatment process of light irradiation is to provide thermal energy for deposition of a precursor for forming a metal-containing thin film, and may be performed according to a conventional method. Preferably, in order to produce a thin film having a desired physical state and composition at a sufficient growth rate, it is preferable to carry out the above treatment process so that the temperature of the substrate in the reactor is 100 to 1,000°C, preferably 200 to 500°C.

In addition, in the treatment process, as described above, in order to help the movement of the reactive gas onto the substrate, to have an appropriate pressure for deposition in the reactor, and to discharge impurities or by-products present in the reactor to the outside, A process of purging an inert gas such as argon (Ar), nitrogen (N ₂ ), or helium (He) may be performed.

As described above, the input of the precursor for forming a metal-containing thin film, the input of the reactive gas, and the input of the inert gas are performed as one cycle. By repeating one cycle or more, a metal-containing thin film can be formed.

Specifically, when an oxidizing gas is used as the reactive gas, the metal-containing thin film prepared may include a metal oxide of Formula 3 below:

[Formula 3]

(M _1-a M" _a )O _b

In Formula 3, a is 0 ≤ a < 1, b is 0 < b ≤ 2, and M is a group 4 or 14 element titanium (Ti), zirconium (Zr), hafnium (Hf), silicon (Si ), germanium (Ge), and tin (Sn), and M" is derived from the second metal precursor, silicon (Si), titanium (Ti), germanium (Ge), strontium (Sr), niobium (Nb) ), barium (Ba), hafnium (Hf), or tantalum (Ta) atoms.

This method of manufacturing a metal-containing thin film uses a precursor for forming a metal-containing thin film having a chemical structure that exhibits a fast initial adsorption rate even in a low-temperature deposition process. The crystallinity can be increased and the content of impurities in the film can be reduced through efficient discharging of the ligand to form a thin film of high dielectric constant. Therefore, the metal-containing thin film formed according to the manufacturing method of the present invention is useful as a material film having a high dielectric constant in a semiconductor device, in particular, a DRAM, CMOS, or the like in a semiconductor memory device.

As another embodiment, a metal-containing thin film formed by the method for forming the metal-containing thin film, and a semiconductor device including the thin film are provided. For example, the semiconductor device may be a semiconductor device including a metal insulator metal (MIM) for random access memory (RAM).

In addition, since the semiconductor device has the same configuration as a typical semiconductor device, except that the metal-containing thin film according to the present invention is included in a material film requiring high dielectric properties such as DRAM in the device, the configuration of the semiconductor device in the present specification A detailed description of the will be omitted.

Although the present invention has been described with reference to preferred embodiments as described above, it is not limited to the above embodiments and various modifications are made by those skilled in the art within the scope of not departing from the spirit of the present invention. and can be changed. Such modifications and variations are intended to fall within the scope of the present invention and the appended claims.

Claims (8)

A precursor for forming a metal-containing thin film comprising a metal-containing compound represented by the following Chemical Formula 1 or Chemical Formula 2.

[Formula 1]

[Formula 2]

In Formulas 1 and 2, M is any one of Ti, Zr, Hf, Si, Ge, and Sn, and L is each independently a hydrogen atom, a C ₁ -C ₆ alkyl group, OR, NHR, NRR', or CF ₃ and R and R' are each independently a hydrogen atom or a C ₁ -C ₆ alkyl group, an alkenyl group, a vinyl group, or an allyl group, and X is O or NHR.
The method according to claim 1,
The precursor for forming a metal-containing thin film is a precursor for forming a metal-containing thin film, characterized in that it comprises a solvent selected from tertiary amines, ethers, C ₁ -C _{16 saturated or unsaturated hydrocarbons, and aromatic compounds.}
3. The method according to claim 2,
The solvent is a precursor for forming a metal-containing thin film, characterized in that it is included in an amount of 1 to 99% by weight based on the total weight of the precursor for forming a metal-containing thin film.
A method for forming a metal-containing thin film comprising depositing the precursor for forming the metal-containing thin film according to claim 1 or 2 on a substrate.
5. The method according to claim 4,
wherein the metal-containing thin film is deposited by atomic layer deposition (ALD) or chemical vapor deposition (CVD).
5. The method according to claim 4,
The depositing step is a method of forming a metal-containing thin film, characterized in that performing the deposition process at a temperature of 350 ℃ or less.
A metal-containing thin film produced by the method for forming a metal-containing thin film according to claim 4.
A semiconductor device comprising the metal-containing thin film according to claim 7 .