KR20190114874A - Precursor for silicon containing thin film, deposition method of film and semiconductor device of the same - Google Patents

Abstract

The present invention relates to a precursor for forming a silicon thin film, comprising a cyclodisilazane compound represented by the formula (1). In the formula (1), R_1 and R_2 are each a phenyl group or an amine group or an alkylsilyl group including or without a hydrogen atom or a C_1-C_5 linear or branched alkyl group or alkylene group or a C_1-C_5 substituent, wherein the total number of carbon atoms of R_1 and R_2 is two or more.

Description

A precursor for forming a silicon thin film, a method for forming a silicon-containing thin film using the same, and a semiconductor device including the silicon-containing thin film. {PRECURSOR FOR SILICON CONTAINING THIN FILM, DEPOSITION METHOD OF FILM AND SEMICONDUCTOR DEVICE OF THE SAME}

The present invention relates to a precursor for forming a silicon thin film, a method for forming a silicon-containing thin film using the same, and a semiconductor device including the silicon-containing thin film, and more particularly, a silicon oxide film, a nitride film, and an oxynitride film including a cyclodisilazane compound. The present invention relates to a precursor for forming a silicon thin film, a method for forming a silicon-containing thin film using the same, and a semiconductor device including the silicon-containing thin film.

Silazane compounds are widely used as precursors for forming silicon thin films. Korean Patent Publication No. 10-1060911 discloses a technique of forming a silicon nitride thin film by introducing a monoalkylaminosilane precursor and a reactive gas, and bis (t-butylamino) silane is reacted in Korean Patent Publication No. 10-0323628. The silazane compound is applied to the formation of a thin film of silicon by various reaction conditions, such as a technique for reacting with a gas to deposit a film of an oxygen-containing silicon compound selected from the group consisting of silicon dioxide and silicon oxynitride on a substrate. have.

Since such silazane compounds are mostly compounds containing one silicon atom in one molecule, a nucleation density is relatively low at the time of thin film formation, and thus a problem in that the efficiency of silicon thin film formation cannot be improved.

As a precursor containing one or more silicon atoms, examples of using a silazane compound of Formula B or C can be found in Korean Patent Publication No. 10-0988096, but even in this case, there is a limit to improving the deposition rate per cycle. Appears to be. It is understood that this is due to the fact that two silicon atoms are contained in one molecule in the formula (B) or (C), but due to the stability of the Si—N bond, the silicon thin film cannot be decomposed in a short time.

On the other hand, US Patent No. 7460450 uses a silazane compound having a cyclic structure as a precursor to deposit a silicon nitride film at a relatively low temperature of 500 ° C or lower. Since the cyclic structure is easily decomposed by the ring-opening reaction, it can be deposited at a low temperature, and by applying such a compound, it is expected that an effect of increasing the nucleation density when forming a thin film can be obtained.

Republic of Korea Patent Publication No. 10-1060911 Republic of Korea Patent Registration No. 10-0323628 Republic of Korea Patent Publication No. 10-0988096

The present invention has been made in view of the prior art as described above, to provide a precursor and a method for producing a silicon-containing thin film that can improve the nucleation density when forming a silicon-containing thin film through a cyclodisilazane compound. do.

Silicon precursor for forming a thin film of the present invention for achieving the above object is characterized in that it comprises a cyclodisilazane compound represented by the formula (1).

[Formula 1]

In Chemical Formula 1,

R ₁ and R ₂ are each hydrogen atom or a C ₁ -C ₅ straight or branched alkyl or alkylene group or a C1-C5 a substituent or not a phenyl group or an amine group or an alkylsilyl group does include the, R ₁ And the total number of carbon atoms of R ₂ is 2 or more.

In this case, the precursor may further include a solvent, wherein the solvent is any _one of C ₁ -C ₁₆ saturated or unsaturated hydrocarbon, ketone, ether, glyme, ester, tetrahydrofuran dimethyloxalate, tertiary amine or It may be more than that.

In addition, the solvent may be included in 1 to 99% by weight based on the total weight of the precursor composition for metal film formation.

Method for forming a silicon-containing thin film according to the invention is characterized in that it comprises the step of depositing a silicon-containing thin film on the substrate using a precursor for forming a silicon thin film.

In this case, the precursor for forming the silicon thin film may further include a solvent, and the solvent may be included in an amount of 1 to 99 wt% based on the total weight of the precursor for forming the silicon thin film.

In addition, the silicon-containing thin film may be deposited by any one method of atomic layer deposition, plasma enhanced chemical vapor deposition, or chemical vapor deposition.

The method may also include vaporizing the silicon thin film precursor and transferring the precursor to the inside of the chamber.

In addition, the deposition, the first step of providing a substrate to the reactor; Introducing a silicon precursor containing a cyclodisilazane compound represented by Chemical Formula 1 into the reactor; Purging the reactor with a purge gas; A fourth step of introducing a reactive gas into the reactor; And a fifth step of purging the reactor with purge gas, and the second to fifth steps may be repeated until a deposition film of a desired thickness is formed.

In addition, the deposition is preferably carried out at a temperature of room temperature to 1,000 ℃ and a pressure in the range of 50 mTorr to 760 Torr.

In this case, the reactive gas is 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) Or any one or more of nitrous oxide (N ₂ O), nitrogen dioxide (NO ₂ ), hydrazine (N ₂ H ₄ ), and silane (SiH ₄ ).

In addition, the semiconductor device according to the invention is characterized in that it comprises a silicon-containing thin film produced by the silicon-containing thin film forming method.

According to the precursor according to the present invention and a method for producing the same, the cyclodisilazane compound is used as a precursor, thereby exhibiting an effect of improving nucleation density when forming a silicon thin film.

1 is a gas chromatography (GC) analysis result of a cyclodisilazane compound according to Synthesis Example 1 (a), Synthesis Example 2 (b), and Synthesis Example 3 (c).
2 is a ¹ H-NMR analysis result of the cyclodisilazane compound according to Synthesis Example 1 (a), Synthesis Example 2 (b), Synthesis Example 3 (c).
3 is a thermogravimetric analysis (TGA) result of the cyclodisilazane compound according to Synthesis Example 1 (a), Synthesis Example 2 (b), and Synthesis Example 3 (c).
4 is a step-by-step flow chart of precursor supply, purge, reactant supply, purge included in one cycle of the ALD process.
5 is a result of comparing the Incubation Time of a silicon dioxide (SiO ₂ ) thin film with the cycle number of cycles of cyclodisilazane and BTBAS as a variable.
6 is a result of depositing a silicon dioxide thin film by varying the temperature conditions of the substrates of cyclodisilazane and BTBAS.

Hereinafter, the present invention will be described in more detail. The terms or words used in this specification and claims are not to be construed as being limited to their ordinary or dictionary meanings, and the inventors may appropriately define the concept of terms in order to best describe their invention. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the present invention.

The precursor for forming a silicon thin film according to the present invention is characterized in that it comprises a cyclodisilazane compound represented by the formula (1).

[Formula 1]

In Chemical Formula 1,

R ₁ and R ₂ are each hydrogen atom or a C ₁ -C ₅ straight or branched alkyl or alkylene group or a C1-C5 a substituent or not a phenyl group or an amine group or an alkylsilyl group does include the, R ₁ And the total number of carbon atoms of R ₂ is 2 or more, preferably 3 or more.

The cyclodisilazane compound is excellent in reactivity with the surface of the substrate to be deposited by the ring-opening reaction, and since two silicon atoms are contained in one molecule, the cyclodisilazane compound exhibits an effect of improving nucleation density in the thin film formation process.

In the present invention, the cyclodisilazane compound according to Formula 1 is a compound partially substituted by an alkyl group or an alkenyl group. For example, 2,4-diethyl-1,1,3,3-tetramethylcyclodisilazane, 2,4-dipropyl-1,1,3,3-tetramethylcyclodisilazane, 2, 4-divinyl-1,1,3,3-tetramethylcyclodisilazane, 2-methyl-4-ethyl-1,1,3,3-tetramethylcyclodisilazane, 2-methyl-4-vinyl -1,1,3,3-tetramethylcyclodisilazane, 2,4-diisopropyl-1,1,3,3-tetramethylcyclodisilazane, 2,4-dibutyl-1,1, 3,3-tetramethylcyclodisilazane, 2,4-diisobutyl-1,1,3,3-tetramethylcyclodisilazane, 2-ethyl-4-isopropyl-1,1,3,3 Tetramethylcyclodisilazane, 2-ethyl-4-butyl-1,1,3,3-tetramethylcyclodisilazane, 2-ethyl-4-isobutyl-1,1,3,3-tetramethyl Cyclodisilazane etc. are mentioned.

Such cyclodisilazane has a structure similar to that of FIG. 3A disclosed in the prior art U.S. Patent No. 747450, but the substituents are bonded to the positions 1 and 3 in that the substituents are bonded to the 2nd and 4th positions. It is different from the chemical formula. This is because the substituents bound to the nucleus play an important role because cyclodisilazane of the prior art is intended for decomposition at low temperature, but in order to increase the nucleation density in the present invention, the speed of the ring-opening reaction is more important than the thermal decomposition efficiency. Because of the difference that appears.

In particular, in the general formula (1) of the present invention, when the total number of carbon atoms of R ₁ and R ₂ is 3 or more, the ring-opening reaction is fast, and thus, nucleation is rapidly formed when the thin film is formed. That is, when the total number of carbon atoms of R ₁ and R ₂ is 3 or less, or when an alkyl group causing steric hindrance at the 1 and 3 positions of cyclodisilazane is bonded, the ring-opening reaction is reduced, resulting in a short time of deposition process. It has been found that while sufficient nucleation density cannot be achieved. In addition, the solubility in various solvents was found to be easy to manufacture in a solution state.

Cyclodisilazane of Formula 1 may be synthesized by the reaction of dichlorosilane and amine. For example, 2,4-diisopropyl-1,1,3,3-tetramethylcyclodisilazane can be synthesized through the same route as in Scheme 1 below.

Scheme 1

When the silicon thin film is manufactured by applying the precursor as described above, the thin film is formed through atomic layer deposition or plasma enhanced chemical vapor deposition as well as conventional chemical vapor deposition. can do.

In addition, depending on the deposition method, the precursor may be dissolved in a solvent and used. In this case, any one or a mixture of C ₁ -C ₁₆ saturated or unsaturated hydrocarbons, ketones, ethers, glymes, esters, tetrahydrofuran, dimethyloxalate, tertiary amines can be used. Examples of the saturated or unsaturated hydrocarbons of C ₁ -C ₁₆ include toluene, heptane and the like, and dimethylethylamine may be mentioned as the tertiary amine.

In addition, when the solvent is included, it is preferably included in 1 to 99% by weight based on the total weight of the precursor for forming the silicon thin film.

Method for forming a silicon-containing thin film of the present invention is characterized in that it comprises the step of depositing a silicon-containing thin film on the substrate using the precursor for forming the silicon thin film.

In this case, the precursor for forming the silicon thin film may further include a solvent, and the solvent may be included in an amount of 1 to 99 wt% based on the total weight of the precursor for forming the silicon thin film.

Specifically, the method of manufacturing a silicon thin film using the precursor for silicon thin film of Chemical Formula 1 may be performed according to a method of manufacturing a silicon thin film by conventional deposition, except that the compound of Chemical Formula 1 is used as a precursor. .

 That is, a first step of providing a substrate to the reactor; Introducing a silicon precursor containing a cyclodisilazane compound represented by Chemical Formula 1 into the reactor; Purging the reactor with a purge gas; A fourth step of introducing a reactive gas into the reactor; And a fifth step of purging the reactor with purge gas, and the second to fifth steps may be repeated until a deposition film of a desired thickness is formed. In addition, the deposition may be carried out at a temperature of room temperature to 1,000 ℃ and a pressure in the range of 50 mTorr to 760 Torr. That is, deposition occurs by the ring-opening reaction of the precursor even under a relatively low temperature of the substrate. In addition, various thin films, such as an oxide film, a nitride film, and an oxynitride film, can be formed according to the type of reactive gas.

First, a precursor for a silicon thin film including a cyclodisilazane compound represented by Formula 1 is supplied onto a substrate for forming a silicon thin film located in a reactor. At this time, the substrate for forming the silicon thin film may be used without particular limitation as long as it is used for manufacturing a semiconductor, which needs to be coated by the silicon thin film due to a technical effect. Specifically, silicon substrate (Si), silica substrate (SiO 2), silicon nitride substrate (SiN), silicon oxy nitride substrate (SiON), titanium nitride substrate (TiN), tantalum nitride substrate (TaN), tungsten substrate ( W) or a noble metal substrate, for example, a platinum substrate Pt, a palladium substrate Pd, a rhodium substrate Rh or a gold substrate Au may be used.

In addition, the silicon thin film precursor of Chemical Formula 1 may be transferred through a volatilized gas, or a liquid injection method may be used, such as a liquid injection method or a liquid thin film precursor dissolved in an organic solvent. The method for transferring the silicon thin film precursor to the volatilized gas includes placing a container containing the silicon thin film precursor in a thermostat, followed by bubbling with an inert gas such as helium, neon, argon, krypton, xenon or nitrogen, to form a silicon thin film precursor. Is then evaporated and transferred onto the substrate for forming the metal thin film, or the liquid silicon thin film precursor is vaporized through a vaporizer using a liquid delivery system (LDS) and then transferred onto the substrate for forming the silicon thin film. It can be carried out by.

In addition, a liquid delivery and flash vaporization process unit, such as a turbo vaporizer manufactured by MSP Corporation (MSP Corporation, Shoreview, MN), may be used to combine low volatility materials in a volumetric manner. This can lead to reproducible transport and deposition without thermal decomposition of the precursors. In liquid delivery formulations, the precursors of the present invention may be delivered in pure liquid form or used in compositions comprising a solvent. Thus, in one embodiment, the precursor composition may comprise solvent components of suitable features because they may be desirable and advantageous for certain end use applications for forming films on substrates.

In the case of a liquid transfer method for dissolving and transporting a silicon thin film precursor in an organic solvent, a precursor composition composed of Chemical Formula 1 and a solvent may be used. It can be used when it is difficult to vaporize enough.

For example, a tertiary amine having a boiling point of 70 ° C. or lower, or 30 to 50 ° C., a density of 0.6 to 0.8 g / cm at a room temperature of 25 ° C., and a vapor pressure of 400 to 700 mmHg can be applied. And when it meets the vapor pressure conditions at the same time, the effect of reducing the viscosity and the volatility of the film-forming composition is improved, it was shown that it is possible to form a thin film with improved uniformity and step coating properties.

In one embodiment, the liquid transfer method may be applied when dimethylethylamine is included in an amount of 1 to 99% by weight based on the total weight of the precursor composition. When the content of the tertiary amine is less than 1% by weight, the physical properties of the thin film may be improved. When it is insignificant and exceeds 99% by weight, the concentration of the precursor is low, so the improvement effect on the step coating property may be lowered. Therefore, it is preferable to use within the above range.

In one embodiment, the precursor composition may include the precursor and the tertiary amine in a weight ratio of 90:10 to 10:90. In this case, when the content of the tertiary amine with respect to the precursor material is too low or too high outside the above weight ratio range, there is a concern that the uniformity and the step coverage improvement effect of the thin film may be deteriorated.

As such, by including tertiary amines exhibiting low viscosity and high volatility in the solvent, the precursor composition may exhibit improved viscosity and volatility, increase substrate adsorption efficiency and stability of the precursor during substrate formation, and shorten process time. . In addition, since the precursor material is evaporated in a diluted state in the solvent, it is transported into the deposition chamber in a more uniform state, so that it can be evenly adsorbed on the substrate, resulting in uniformity and step coverage of the deposited thin film. ) Characteristics can be improved. In addition, excess lone pairs in tertiary amines can increase the stability of the precursor material in the substrate adsorption process, thereby minimizing chemical vapor deposition (CVD) in the ALD process.

In one embodiment, a silicon film deposited using the thin film forming method of the present invention is formed in the presence of oxygen using an oxygen source, reagent, or precursor containing oxygen. The oxygen source may be introduced into the reactor in the form of one or more oxygen sources and / or additionally present in other precursors used in the deposition process. Suitable oxygen source gases include, for example, water (H ₂ O) (eg, deionized water, purified water, and / or distilled water), oxygen (O ₂ ), oxygen plasma, ozone (O ₃ ), N ₂ O, NO ₂ , carbon monoxide (CO), carbon dioxide (CO ₂ ), and combinations thereof. For example, the oxygen source may comprise an oxygen source gas introduced into the reactor at a flow rate in the range of about 1 to about 2000 sccm or about 1 to about 1000 sccm. The oxygen source may be introduced for a time ranging from about 0.1 to about 100 seconds. In one particular embodiment, the oxygen source comprises water with a temperature of 10 ° C. or higher. In embodiments in which the film is deposited by an ALD or cyclic CVD process, the precursor pulse may have a pulse duration of greater than 0.01 seconds, the oxygen source may have a pulse width of less than 0.01 seconds, and the water pulse The width may have a pulse width that is less than 0.01 seconds.

In yet another embodiment, the purge width between the pulses may be as small as 0 seconds or continuously pulsed without a purge in between. The oxygen source or reagent is provided at a molecular weight lower than the 1: 1 ratio relative to the silicon precursor, thereby leaving at least some carbon in the dielectric film as it is deposited.

In yet another embodiment, the silicon oxide film may further comprise nitrogen. The film is deposited using the method described above and can be formed in the presence of a nitrogen containing source. The nitrogen containing source may be introduced into the reactor in the form of one or more nitrogen sources and / or additionally present in other precursors used in the deposition process. Suitable nitrogen containing source gases can include, for example, ammonia, hydrazine, monoalkylhydrazines, dialkylhydrazines, nitrogen, nitrogen / hydrogen, ammonia plasmas, nitrogen plasmas, nitrogen / hydrogen plasmas, and mixtures thereof. In certain embodiments, the nitrogen containing source comprises an ammonia plasma or hydrogen / nitrogen plasma source gas introduced into the reactor at a flow rate in the range of about 1 to about 2000 sccm or about 1 to about 1000 sccm. The nitrogen containing source may be introduced for a time ranging from about 0.1 to about 100 seconds. In embodiments in which the film is deposited by an ALD or cyclic CVD process, the precursor pulse may have a pulse width of greater than 0.01 seconds, the nitrogen containing oxygen source may have a pulse width of less than 0.01 seconds, and the water pulse width may be It can have a pulse width that is less than 0.01 seconds.

In another embodiment, the purge width between the pulses may be as low as 0 seconds or continuously pulsed without a purge in between.

In addition, the deposition method may include one or more purge gases. The purge gas used to purge unconsumed reactants and / or reaction byproducts is an inert gas that does not react with the precursor. Such purge gas may include, but is not limited to, argon (Ar), nitrogen (N ₂ ), helium (He), neon, hydrogen (H ₂ ), or mixtures thereof. For example, a purge gas such as Ar may be supplied to the reactor at a flow rate in the range of 10 to about 2000 sccm for about 0.1 to 1000 seconds, thereby purging unreacted materials and by-products that may remain in the reactor.

In addition, each step of supplying a precursor, an oxygen source, a nitrogen containing source, and / or other precursors, source gas, and / or reagents may take time to supply the materials to alter the stoichiometric composition of the dielectric film formed. It can be done by changing.

Energy is applied to one or more of the silicon precursor, oxygen-containing source, or a combination thereof to induce a reaction and form a dielectric film or coating on the substrate, such as heat, plasma, pulsed plasma, helicon plasma, high density plasma. , Inductively coupled plasma, X-ray, e-beam, photon, remote plasma method, and combinations thereof, but is not limited thereto. For example, a secondary RF frequency source can be used to modify the plasma characteristics at the substrate surface. In embodiments where the deposition comprises a plasma, the plasma-generating process may comprise a direct plasma generation process in which the plasma is generated directly in the reactor, or alternatively a remote plasma generation process in which the plasma is generated outside the reactor and provided to the reactor. .

In addition, when supplying the precursor for the silicon thin film of Formula 1, silicon (Si), titanium (Ti), germanium (Ge) as an additional metal precursor in order to further improve the electrical properties, that is, the capacitance in the silicon thin film to be formed finally May optionally further supply a metal precursor comprising at least one metal (M ″) selected from strontium (Sr), niobium (Nb), barium (Ba), hafnium (Hf), tantalum (Ta), and lanthanide atoms The metal precursor may be an alkylamide-based compound or an alkoxy-based compound including the metal. When silicon is used, SiH (N (CH ₃ ) ₂ ) ₃ and Si (N (C ₂ H ₅ ) may be used as the metal precursor. 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, and the like may be used.

The supply of the metal precursor may be carried out in the same manner as the supply method of the precursor for the silicon thin film of Formula 1, the metal precursor may be supplied onto the substrate for forming a thin film together with the precursor for the silicon thin film of Formula 1, or metal It may be supplied sequentially after the supply of the precursor is completed.

The silicon thin film precursor of Formula 1 and optionally the metal precursor as described above is preferably maintained at a temperature of 150 to 600 ℃ before being supplied into the reaction chamber to contact the metal film forming substrate, more preferably 150 It is good to maintain a temperature of from 450 ℃.

Further, prior to the supply of the reactive gas after the supplying of the precursor for the silicon thin film, to assist the movement of the silicon thin film precursor of Formula 1 and optionally the metal precursor onto the substrate, or to have a suitable pressure in the reactor to deposit, In order to release impurities and the like present in the chamber to the outside, a process of purging an inert gas such as argon (Ar), nitrogen (N ₂ ), or helium (He) may be performed. At this time, the purge of the inert gas is preferably carried out so that the pressure in the reactor is 1 to 5 Torr.

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

The reactive gas includes 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 mixtures thereof may be used. When the silicon oxide thin film is formed in the presence of an oxidizing gas such as water vapor, oxygen, ozone, etc., a thin film of silicon single body or silicon nitride may be formed when it is carried out in the presence of a reducing gas such as hydrogen, ammonia, hydrazine or silane. Can be.

In addition, the heat treatment, the plasma treatment or the light irradiation treatment process is to provide thermal energy for the deposition of the metal precursor, it may be carried out according to a conventional method. Preferably, in order to produce a metal thin film having a desired physical state and composition at a sufficient growth rate, it is preferable to carry out the treatment process so that the temperature of the substrate in the reactor is 100 to 1,000 ° C, preferably 300 to 500 ° C. Do.

In addition, in the treatment process, as described above, in order to assist the movement of the reactive gas onto the substrate or to make the inside of the reactor have a suitable pressure for deposition, and to release 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 mentioned above, the process of injecting a precursor for a silicon thin film, injecting a reactive gas, and injecting an inert gas is one cycle. By repeating one or more cycles, a metal-containing thin film can be formed.

Specifically, the metal-containing thin film prepared when the oxidizing gas is used as the reactive gas may include a metal oxide of Formula 2 below:

[Formula 2]

(M _1-a M " _a ) O _b

In Formula 2, a is 0 = a <1, b is 0 <b = 2, M is selected from the group consisting of Zr, Hf and Ti, M "is derived from the second metal precursor, silicon (Si), titanium (Ti), germanium (Ge), strontium (Sr), niobium (Nb), barium (Ba), hafnium (Hf), tantalum (Ta) and lanthanide atoms.

The method of manufacturing a silicon thin film can be carried out at a higher temperature than in the prior art during the deposition process by using a silicon thin film precursor having excellent thermal stability, and without impurity contamination such as particles or carbon due to pyrolysis of the precursor. It is possible to form a high purity silicon, silicon oxide or silicon nitride thin film. Accordingly, the silicon-containing thin film formed according to the manufacturing method of the present invention is useful for high dielectric material films in semiconductor devices, particularly DRAM, CMOS, etc. in semiconductor memory devices.

As another embodiment, there is provided a silicon thin film formed by the method for forming a silicon thin film and a semiconductor device including the thin film. Specifically, 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 is the same as the structure of a conventional semiconductor device except that the silicon-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 is described herein. A detailed description of the description is omitted.

Hereinafter, the effects of the present invention will be described.

Synthesis Example 1

N, N'-diisopropyltetramethylcyclodisilazane (N, N'-Diisopropyltetramethylcyclodisilazane) is synthesized by synthesizing bis (isopropylamino) dimethylsilane (Bis (isopropylamino) dimethylsilane) as in Scheme 2 below. Synthesized.

Scheme 2

Synthesis of Bis (isopropylamino) dimethylsilane

In a flame-dried 2,000 ml Schlenk flask, 100 g (0.774 mol, 1 equivalent) of dimethyldichlorosilane and 206 g (3.49 mol, 4.5 equivalents) of isopropylamine were stirred for 19 hours under a nitrogen atmosphere in 1500 ml of ether. To prepare a suspension. The filtrate was obtained through a filter in the suspension where the reaction was completed, and then the solvent and volatile side reactions were removed under reduced pressure. The remaining light yellow liquid was then distilled under reduced pressure to give 84.3 g (yield: 62%) of a colorless liquid compound bis (isopropylamino) dimethylsilane.

The product was measured by ¹ H-NMR (400 MHz, C ₆ D ₆ , 25 ° C.). As a result, δ 3.134-3.076 (m, 1H, (CH ₃ ) ₂ CH), δ 1.045-1.030 (d, 6H, ( CH ₃ ) ₂ CH), δ 0.287 (s, 1H, NH), and δ 0.0821 (s, 3H, SiCH ₃ ) were identified. Boiling point (bp) was 62 ° C (33 Torr).

Synthesis of N, N'-Diisopropyltetramethylcyclodisilazane

In a flame dried 2000 ml Schlenk flask, 40 g (0.229 mol, 1 equivalent) of bis (isopropylamino) dimethylsilane and 184 ml (0.458 mol, 2 equivalents) of n-butyllithium in 800 ml of ether 78 ° C. was added slowly under nitrogen atmosphere to mix, and then refluxed for 1 hour to prepare a suspension. 29.6 g (0.229 mol, 1 equivalent) of dimethyldichlorosilane was slowly added to the suspension under -78 ° C and nitrogen atmosphere, mixed and refluxed for 3 hours to complete the reaction. The filtrate was obtained through a filter in the suspension where the reaction was completed, and then the solvent and volatile side reactions were removed under reduced pressure. Subsequently, the remaining light yellow liquid was distilled under reduced pressure to obtain 32.6 g (yield: 61%) of a colorless liquid compound, N, N'-Diisopropyltetramethylcyclodisilazane.

The product was measured by ¹ H-NMR (400 MHz, C ₆ D ₆ , 25 ° C.), and δ 3.245-3.182 (m, 1H, (CH ₃ ) ₂ CH), δ 1.072-1.056 (d, 6H, ( Specific peaks of CH ₃ ) ₂ ), δ 0.319 (s, 6H, Si (CH ₃ ) ₂ ) were observed. Moreover, boiling point (bp) was 89 degreeC (29 Torr).

Synthesis Example 2

N, N'-dibutyltetramethylcyclodisilazane (N, N'-Dibutyltetramethylcyclodisilazane) was synthesized by synthesizing bis (butylamino) dimethylsilane as in Scheme 3 below. .

Scheme 3

Synthesis of Bis (butylamino) dimethylsilane

In a flame-dried 2,000 ml Schlenk flask, 70 g (0.542 mol, 1 equivalent) of dimethyldichlorosilane and 178 g (2.44 mol, 4.5 equivalents) of butylamine in 1,050 ml of n-hexane for 3 hours under nitrogen atmosphere Reflux to prepare a suspension. The filtrate was obtained through a filter in the suspension where the reaction was completed, and then the solvent and volatile side reactions were removed under reduced pressure. The remaining light yellow liquid was then distilled under reduced pressure to give 55.3 g (yield: 50%) of a colorless liquid compound, bis (butylamino) dimethylsilane.

The product was measured by ¹ H-NMR (400 MHz, C ₆ D ₆ , 25 ° C.). As a result, δ 2.779-2.726 (m, 2H, CH ₂ ), δ 1.383-1.247 (m, 4H, CH ₂ CH ₂ ) , specific peaks of δ 0.924-0.888 (t, 3H, CH ₃ ), δ 0.360 (s, 1H, NH) and δ 0.100 (s, 3H, SiCH ₃ ) were identified. In addition, the boiling point (bp) was 71 ° C (3 Torr).

Synthesis of N, N'-Dibutyltetramethylcyclodisilazane

In a flame dried 2000 ml Schlenk flask, 51 g (0.229 mol, 1 equivalent) of bis (butylamino) dimethylsilane and 204 ml (0.503 mol, 2 equivalents) of n-butyllithium were added in 877 ml of tetrahydrofuran. A suspension was prepared by slowly adding to -78 ° C and mixing under a nitrogen atmosphere and refluxing for 1 hour. 32.1 g (0.251 mol, 1 equivalent) of dimethyldichlorosilane was slowly added to the suspension under -78 ° C and nitrogen atmosphere, mixed, and stirred for 2 hours to complete the reaction. The filtrate was obtained through a filter in the suspension where the reaction was completed, and then the solvent and volatile side reactions were removed under reduced pressure. Subsequently, the remaining pale yellow liquid was distilled under reduced pressure to obtain 29.2 g (yield: 44%) of a colorless liquid compound, N, N'-Dibutyltetramethylcyclodisilazane.

The product was measured by ¹ H-NMR (400 MHz, C ₆ D ₆ , 25 ° C.). As a result, δ 2.818-2.784 (t, 2H, CH ₂ ), δ 1.446-1.290 (m, 4H, CH ₂ CH ₂ ) , specific peaks of δ 0.928-0.892 (t, 3H, CH ₃ ), δ 0.283 (s, 6H, Si (CH ₃ ) ₂ ) were identified. Moreover, boiling point (bp) was 77 degreeC (2.7 Torr).

Synthesis Example 3

N, N'-dicyclopentyltetramethylcyclodisilazane (N, N'-Dicyclopentyltetramethylcyclodisilazane) is synthesized by synthesizing bis (cyclopentylamino) dimethylsilane (Bis) as shown in Scheme 4 below. Synthesized.

Scheme 4

Synthesis of Bis (cyclopentylamino) dimethylsilane

In a flame-dried 2,000 ml Schlenk flask, 90 g (0.697 mol, 1 equivalent) of dimethyldichlorosilane and 267 g (3.13 mol, 4.5 equivalent) of cyclopentylamine in 1,350 ml of n-hexane for 5 hours under nitrogen atmosphere To reflux to prepare a suspension. The filtrate was obtained through a filter in the suspension where the reaction was completed, and then the solvent and volatile side reactions were removed under reduced pressure. The remaining light yellow liquid was then distilled under reduced pressure to give 102 g (yield: 64%) of a colorless liquid compound, bis (cyclopentylamino) dimethylsilane.

The product was measured by ¹ H-NMR (400 MHz, C ₆ D ₆ , 25 ° C.). As a result, δ 3.379-3.282 (m, 1H, C ₅ H ₉ ), δ 1.876-1.796 (m, 2H, C ₅ H ₉ ), δ 1.662-1.563 (m, 2H, C ₅ H ₉ ), δ 1.503-1.396 (m, 2H, C ₅ H ₉ ), δ 1.212-1.121 (m, 2H, C ₅ H ₉ ), δ 0.454 Specific peaks of (s, 1H, NH) and δ 0.119 (s, 3H, SiCH ₃ ) were found. Moreover, boiling point (bp) was 103 degreeC (3 Torr).

Synthesis of N, N'-Dicyclopentyltetramethylcyclodisilazane

In a flame-dried 2,000 ml Schlenk flask, 100 g (0.440 mol, 1 equivalent) of bis (cyclopentylamino) dimethylsilane and 350 ml (0.883 mol, 2 equivalents) of n-butyllithium were charged in 1500 ml of tetrahydrofuran. The mixture was slowly added and mixed under a nitrogen atmosphere of -78 ° C, and then refluxed for 1.5 hours to prepare a suspension. 57 g (0.441 mol, 1 equivalent) of dimethyldichlorosilane was slowly added to the suspension under −78 ° C. and a nitrogen atmosphere, mixed, and stirred for 3 hours to complete the reaction. The filtrate was obtained through a filter in the suspension where the reaction was completed, and then the solvent and volatile side reactions were removed under reduced pressure. Subsequently, the remaining light yellow liquid was distilled under reduced pressure to obtain 82 g (yield: 66%) of a colorless liquid compound, N, N'-Dicyclopentyltetramethylcyclodisilazan.

The product was measured by ¹ H-NMR (400 MHz, C ₆ D ₆ , 25 ° C.). As a result, δ 3.363-3.293 (m, 1H, C ₅ H ₉ ), δ 1.771-1.624 (m, 4H, C ₅ H ₉ ), δ 1.519-1.404 (m, 2H, C ₅ H ₉ ), δ 1.342-1.251 (m, 2H, C ₅ H ₉ ), δ 0.323 (s, 6H, Si (CH ₃ ) ₂ ) Was confirmed. Moreover, boiling point (bp) was 86 degreeC (0.3 Torr).

[Comparative Example]

For comparison, bis (t-butyl amino) silane (Bis (tert-Butyl Amino) Silane (BTBAS)) was synthesized as follows.

In a flame-dried 2,000 ml Schlenk flask, 100 g (0.99 mol, 1 equivalent) of dichlorosilane and 325 g (4.45 mol, 4.5 equivalents) of tertbutylamine were refluxed in 1,500 ml of n-hexane for 12 hours under nitrogen atmosphere. To prepare a suspension. The filtrate was obtained through a filter in the suspension where the reaction was completed, and then the solvent and volatile side reactions were removed under reduced pressure. The remaining transparent liquid was then distilled under reduced pressure to yield 143.78 g (yield: 83.3%) of a colorless liquid compound bis (tertbutylamino) silane.

The product was measured by ¹ H-NMR (400 MHz, C ₆ D ₆ , 25 ° C.). As a result, δ 4.797-7.783 (t, 1H, SiH), δ 1.157 (s, 9H, (CH ₃ ) ₃ ), δ A specific peak of 0.802 (s, 1H, NH) was found and the boiling point (bp) was 167 ° C.

[Thin film deposition test]

Experiments of depositing a thin film using the cyclodisilazane compound and BTBAS prepared by Synthesis Examples 1 to 3 and Comparative Synthesis Example as a silicon (Si) precursor were carried out.

In depositing a Si precursor on a wafer substrate using the ALD method, the substrate deposited a thin film (oxide / nitride) using temperature conditions, injection time of precursors and reactants as variables. In the ALD process, as shown in FIG. 4, four stages of precursor supply, purge, reactant supply, and purge are formed in one cycle, one layer of thin film is formed during one cycle, and the cycle is repeated to form a thin film having a desired thickness.

In transferring the Si precursor from the canister vessel to the reaction chamber, the precursor itself was supplied to the reaction chamber by a method of supplying Vapor of the precursor itself, heating the canister vessel at an appropriate level, and supplying it by using a transporter. In transferring the Si precursor from the canister to the reaction chamber, the supply gas line from the canister to the reaction chamber was maintained at an appropriate temperature so that the transferred Si precursor did not remain inside the gas line.

In order to purge after the precursor supply or the reactant supply, an inert gas was used to remove unreacted gases, reaction by-products, and the like in the gas line and the reaction chamber. The gas used as the purge gas uses an extremely low reactivity gas and a gas that is not reactive with the precursor or the reactant. The purge after the precursor supply or the reactant supply was supplied in an amount and time sufficient to remove all of the unreacted gas and the reaction by-products of the reaction chamber.

In addition, the reactant and the precursor are only in the reaction chamber for the supply of the reactant, it was configured and supplied so as not to meet in other areas. Gases for supplying the precursor and the reactants to the reaction chamber were separately configured to prevent process reactions in the regions other than the reaction chamber.

In the deposition experiment for comparing Synthesis Example 1 (cyclodisilazane) and Comparative Example (BTBAS), the reactant was O ₃ .

In the case of BTBAS, the temperature range was increased by 50 ° C to 300, 350, 400, 450, 500, 550, 600 ° C. The precursor was injected for 0.5 seconds, then purged for 10 seconds, the reaction was injected for 0.5 seconds, and then cycled for 10 seconds. Since the vapor pressure of BTBAS was generated in sufficient quantity without the incombustible gas for movement, the ALD process in the form of steam was carried out.

In the case of cyclodisilazane, the temperature range was increased by 50 ° C to 200, 250, 300, 350, 400, 450, and 500 ° C. The precursor was injected for 3.0 seconds, then purged for 10 seconds, the reaction was injected for 2.5 seconds, and then 1 cycle of deposition was carried out by purging for 10 seconds. In the case of cyclodisilazane, argon (30 sccm) was applied as a carrier gas for transporting the precursor in a bubbler form.

5 is a result of comparing the Incubation Time of silicon dioxide (SiO ₂ ) thin film with the cycle number of cycles of cyclodisilazane and BTBAS as variables. In the deposition conditions, all variables other than the number of cycles proceeded to the reference conditions of each precursor.

Observing the change in GPC (Growth Per Cycle) of the BTBAS and Cyclic silazane according to the number of cycles in FIG. 5 shows that the BTBAS precursor requires 30 cycles of incubation time until the cycle of GPC saturation. In this case, there was no incubation time for saturation of GPC and it was judged that it was advantageous to form silicon thin film of the same thickness in a shorter time than BTBAS. When the incubation time required for GPC stabilization is low or short, the time required for the formation of the target thin film is reduced, which is advantageous for the operation of the thin film formation process and the reduction and density of the silicon thin film.

6 is a result of depositing a silicon dioxide thin film by varying the temperature (300 ℃ ~ 600 ℃) conditions of the substrate of cyclodisilazane and BTBAS. At this time, the ALD cycle was performed 50 times and the deposition rate per cycle was measured.

Looking at the results of the temperature-specific GPC shown in Figure 6, the cyclodisilazane precursor exhibits ALD (Atomic Layer Deposition) deposition characteristics in the temperature range of 300 to 400 ℃ with the BTBAS precursor is expected to have no significant difference in the formation of the silicon thin film It became.

In addition, the controllability of the thin film and the composition analysis in the thin film was examined through the deposition time of cyclodisilazane and the reactants or the deposition of precursors having different temperatures. The thickness of the deposited thin film was measured by an ellipsometer, and the content of Si and carbon in the thin film was measured by Time of Flight Secondary Ion Mass Spectrometer.

The results are shown in Table 1.

Synthesis Example 1 Comparative example C 572 761 Cl 96 153 Si 689 329 O 22,251 12,073

As a result of the analysis of ToF-SIMS, when the cyclodisilazane was used as a precursor, the contents of C and Cl, which are impurities, were greatly reduced compared to BTBAS, and the relative values of Si and O were found to be large. When applied, it was confirmed that the nucleation density significantly increased.

Although the present invention has been described with reference to preferred embodiments, the present invention is not limited to the above embodiments, and various modifications by those skilled in the art to which the present invention pertains may be made without departing from the spirit of the present invention. Changes are possible. Such modifications and variations are intended to fall within the scope of the invention and the appended claims.

Claims (13)

A precursor for forming a silicon thin film, comprising a cyclodisilazane compound represented by Formula 1.

[Formula 1]

In Chemical Formula 1,
R ₁ and R ₂ are each hydrogen atom or a C ₁ -C ₅ straight or branched alkyl or alkylene group or a C1-C5 a substituent or not a phenyl group or an amine group or an alkylsilyl group does include the, R ₁ And the total number of carbon atoms of R ₂ is 2 or more.
The method according to claim 1,
A precursor for forming a silicon thin film, further comprising a solvent.
The method according to claim 2,
The solvent is a precursor for forming a silicon thin film, characterized in that any one or more of C ₁ -C ₁₆ saturated or unsaturated hydrocarbon, ketone, ether, glyme, ester, tetrahydrofuran dimethyl oxalate, tertiary amine.
The method according to claim 2,
The solvent is a precursor for forming a silicon thin film, characterized in that contained in 1 to 99% by weight based on the total weight of the precursor for forming a silicon thin film.
A method of forming a silicon-containing thin film, comprising depositing a silicon-containing thin film on a substrate using the precursor for forming a silicon thin film according to claim 1 or 2.
The method according to claim 5,
The method for forming a silicon-containing thin film, characterized in that the precursor for forming a silicon thin film further comprises a solvent.
The method according to claim 6,
The solvent is a silicon-containing thin film forming method, characterized in that contained in 1 to 99% by weight based on the total weight of the precursor for forming a silicon thin film.
The method according to claim 5 or 6,
The silicon-containing thin film is deposited by any one of atomic layer deposition (Plasma Enhanced Chemical Vapor Deposition), or chemical vapor deposition (Chemical Vapor Deposition). Forming method.
The method according to claim 5,
And vaporizing the precursor for forming the silicon thin film and transferring the precursor to the inside of the chamber.
The method according to claim 5 or 6,
The deposition is
Providing a substrate in a reactor;
Introducing a silicon precursor containing a cyclodisilazane compound represented by Chemical Formula 1 into the reactor;
Purging the reactor with a purge gas;
A fourth step of introducing a reactive gas into the reactor; And
A fifth step of purging said reactor with purge gas;
Wherein the second to fifth steps are repeated until a deposited film of desired thickness is formed.
The method according to claim 10,
The reactive gas may be 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 Method of forming a silicon-containing thin film, characterized in that any one or more of nitrogen (N ₂ O), nitrogen dioxide (NO ₂ ), hydrazine (N ₂ H ₄ ), and silane (SiH ₄ ).
The method according to claim 10,
The deposition is a silicon-containing thin film forming method, characterized in that carried out at a temperature of room temperature to 1,000 ℃ and a pressure in the range of 50 mTorr to 760 Torr.
A semiconductor device comprising a silicon-containing thin film produced by the method for forming a silicon-containing thin film of claim 5 or 6.

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