KR100829608B1 - Method of manufacturing a thin layer and methods of manufacturing a gate structure and a capacitor using the same - Google Patents

Abstract

A method of manufacturing a thin film and a method of manufacturing a gate structure and a capacitor using the same are disclosed. According to the thin film manufacturing method, it is heated to a temperature of 60 to 95 ℃ to provide an organometallic precursor represented by the following formula having a saturated vapor pressure of 1 Torr to 5 torr to the top of the substrate. An oxidant comprising oxygen for oxidizing the organometallic precursor is then provided on top of the substrate. Thereafter, the organometallic precursor provided on the substrate and the oxidant are chemically reacted. The result is a thin film comprising a metal-oxide. The thin film may be easily applied to a gate insulating film of a gate structure, a dielectric film of a capacitor, or the like.

Description

METHODS OF MANUFACTURING A THIN LAYER AND METHODS OF MANUFACTURING A GATE STRUCTURE AND A CAPACITOR USING THE SAME}

1 to 5 are cross-sectional views showing a thin film manufacturing method according to Example 1 of the present invention.

6 is a process flowchart showing a thin film manufacturing method according to Example 2 of the present invention.

7 to 10 are cross-sectional views illustrating a method of manufacturing a gate structure in accordance with an embodiment of the present invention.

11 to 14 are cross-sectional views illustrating a method of manufacturing a capacitor according to an embodiment of the present invention.

15 is a graph showing the saturation vapor pressure change of hafnium precursors with temperature change.

FIG. 16 is a graph illustrating a change in saturated vapor pressure of a zirconium precursor with temperature change. FIG.

17 shows organometallic precursors (t-BuN) Hf (N (CH ₃ ) (C ₂ H ₅ )) ₂ , TEMAH and (t-BuN) Zr (N (CH ₃ ) (C ₂ H ₅ )) ₂ It is a graph showing the results of thermogravimetric analysis.

18 is a graph showing leakage current characteristics of a capacitor to which a hafnium-oxide film of the present invention is applied as a dielectric film.

19 is a graph showing leakage current characteristics of a capacitor formed using the zirconium-aluminum oxide film of the present invention.

20 is a graph showing step coverage of zirconium oxide films according to the present invention.

The present invention relates to a method for manufacturing a thin film, a method for manufacturing a gate structure and a capacitor using the same, and more particularly, a method for manufacturing a thin film including a metal oxide using an organometallic precursor, and a method for manufacturing a gate structure and a capacitor using the same. It is about.

Recently, thin films such as a gate insulating film of a MOS transistor, a dielectric film of a capacitor, or a dielectric film of a flash memory device have been formed using a material having a high-k dielectric. This reduces the leakage current generated between the gate electrode and the channel or between the lower electrode and the upper electrode even though the thin film made of the material having the high dielectric constant maintains a thin equivalent oxide thickness (EOT). This is because the coupling ratio of the flash memory device can be improved.

Examples of the material having the high dielectric constant include Ta ₂ O ₅ , Y ₂ O ₃ , HfO ₂ , ZrO ₂ , Nb ₂ O ₅ , BaTiO ₃ , SrTiO ₃ , and the like. The hafnium oxide layer HfO ₂ may be formed using a hafnium precursor and an oxidizing agent in the thin film made of the material having the high dielectric constant.

The hafnium precursor (Hf-precursor) for forming the hafnium oxide film (tetrakis ethyl methyl amino hafnium, Hf [NC ₂ H ₅ CH ₃ ] ₄ ) or HTTB (hafnium tetrakis butoxide, Hf [OC ₄ H ₉ ] ₄ ) Etc. can be used. However, although the dielectric properties of the hafnium oxide film formed by applying the TEMAH are good, when the TEMAH is heated to about 90 ° C. in the canister and formed in a gaseous state, the saturated vapor pressure in the canister has a low value of only 1 torr. . The fact that the TEMAH has a low saturated vapor pressure causes a long time to supply the hafnium precursor into the process chamber for forming the hafnium oxide film. This increase in time has a problem of reducing the throughput of the semiconductor manufacturing process for forming the hafnium oxide film. In addition, when the heating temperature is increased to 90 ° C. or more to increase the saturated vapor pressure of the TEMAH, there is a limit in increasing the saturated vapor pressure of the hafnium precursor because the problem of deterioration of the TEMAH occurs.

Therefore, in order to manufacture a metal oxide film more quickly with the same dielectric properties as in the prior art, an organic metal precursor having a saturated vapor pressure of 1 torr or higher at 90 ° C. or less and excellent reactivity with an oxidant and a method of manufacturing the metal oxide film using the same are required. .

One object of the present invention is to provide a method for manufacturing a thin film including a metal oxide capable of increasing the throughput of a semiconductor manufacturing process while having electrical properties similar to hafnium oxide film formed of TEMAH.

Another object of the present invention is to provide a method for manufacturing a gate structure including a gate insulating film made of the metal oxide.

Still another object of the present invention is to provide a method of manufacturing a capacitor including the dielectric film made of the metal oxide.

According to the thin film manufacturing method according to a preferred embodiment of the present invention for achieving the above object, first to the organic metal precursor is heated to a temperature of 60 to 95 ℃ having a saturated vapor pressure of 1 Torr to 5 torr and represented by the following formula Serve as the top of the substrate. An oxidant comprising oxygen for oxidizing the organometallic precursor is then provided on top of the substrate. Thereafter, the organometallic precursor provided on the substrate and the oxidant are chemically reacted to form a thin film including metal-oxide on the surface of the substrate.

According to another preferred method of manufacturing a thin film according to the present invention for achieving the above object, it is heated to a temperature of 60 to 95 ℃ as the first reaction material has a saturated vapor pressure of 1 Torr to 5 torr and is represented by the following formula An organometallic precursor is introduced to the top of the substrate. Subsequently, some of the metal precursor molecules constituting the organometallic precursor are chemisorbed on the substrate, and the rest of the chemisorbed metal precursor molecules are physically adsorbed. Subsequently, an oxidant containing oxygen is introduced into the upper portion of the substrate. Subsequently, the molecules of the organometallic precursor chemisorbed on the substrate and the oxidant are chemically reacted to form a first solid material containing a metal-oxide on the substrate. Subsequently, an organoaluminum precursor, which is a second reactant, is introduced onto the first solid phase material. Subsequently, a part of the aluminum precursor molecules constituting the organoaluminum precursor is chemisorbed on the first solid material and the rest of the chemisorbed aluminum precursor molecules is physically adsorbed. An oxidant is then introduced on top of the first solid material. Subsequently, a chemically adsorbed aluminum precursor molecule and the oxidant are chemically reacted on the first solid material to form a second solid material containing aluminum oxide on the first solid material. As a result, a solid thin film containing a metal-aluminum-oxide is formed.

According to a method for manufacturing a gate structure of a semiconductor device according to a preferred embodiment of the present invention for achieving the above another object is first heated to a temperature of 60 to 95 ℃ having a saturated vapor pressure of 1 Torr to 5 torr and of the gas represented by the following formula An oxidant comprising an organometallic precursor and oxygen for oxidizing the organometallic precursor is provided over the substrate. A thin film including a metal oxide is formed on the surface of the substrate by the reaction of the organometallic precursor provided on the substrate with the oxidant. The thin film is repeatedly formed to form a gate insulating film on the substrate. A conductive film is formed on the gate insulating film. The conductive film and the gate insulating film are patterned sequentially. As a result, a gate structure including a gate insulating film pattern and a conductive film pattern made of the metal oxide is formed on the substrate.

According to a method of manufacturing a capacitor of a semiconductor device according to an embodiment of the present invention for achieving the above another object, first to form a lower electrode on a substrate. Subsequently, the lower electrode was formed by heating to a temperature of 60 to 95 ° C. and having a saturated vapor pressure of 1 Torr to 5 torr, and an oxidant including an organometallic precursor of a gas represented by the following formula and oxygen for oxidizing the organometallic precursor. Serve as the top of the substrate. Subsequently, the metal oxide is formed on the surface of the lower electrode by the reaction of the organometallic precursor provided on the substrate with the oxidant. Subsequently, the thin film is repeatedly formed to form a dielectric film on the lower electrode. Subsequently, an upper electrode is formed on the dielectric layer. As a result, a capacitor comprising the lower electrode, the dielectric film made of the metal oxide and the upper electrode is formed on the substrate.

[Formula]

R ₃ -N = M (N (R ₁ ) (R ₂ )) ₂

In the above formula, R1 to R3 are each independently hydrogen or an alkyl group having 1 to 5 carbon atoms, M is titanium (Ti), zirconium (Zr) or hafnium (Hf).

According to one embodiment, the organometallic precursor is formed by heating a liquid organometallic precursor to a temperature of 75 to 85 ℃, has a saturated vapor pressure of about 3 Torr to 5 torr in the canister. In this case, the organometallic precursor is in a gaseous state.

The organometallic precursor may be supplied onto a substrate together with a carrier gas, and examples of the carrier gas may include argon gas, nitrogen gas, helium gas, and the like.

As an example, the method may further include first purging the substrate using the purge gas after the organometallic precursor is provided and second purging the substrate using the purge gas after the oxidant is provided. have. The thin film is formed by performing an atomic lamination method, and may be formed at a temperature of 250 to 400 ° C. and a pressure of 0.5 to 3.0 torr.

According to the present invention, the organometallic precursor represented by the above formula applied when forming a thin film containing a metal oxide not only has a higher saturated vapor pressure than conventional metal precursors (TEMAH, TEMAZ), but also has high reactivity with an oxidizing agent. . Therefore, it is possible to improve the throughput and process characteristics of the step cover during the thin film manufacturing process. In addition, the present invention can easily produce a thin film having a high dielectric constant and good leakage current. As a result, the thin film can be easily applied to a gate insulating film of a gate structure, a dielectric film of a capacitor, a dielectric film of a flash memory device, and the like.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Thin film manufacturing method 1

1 to 5 are short views showing the thin film manufacturing method according to the first embodiment of the present invention.

Referring to FIG. 1, a substrate 10 for forming a thin film is positioned in a process chamber 50. In this case, when the internal temperature of the process chamber 50 is less than about 250 ° C., the reactivity of the organometallic precursor in a gaseous state is not preferable in a subsequent process. On the other hand, when the temperature exceeds about 450 ℃ crystallization of the thin film to be formed on the substrate 10 proceeds, it is not preferable because it shows the characteristics of chemical vapor deposition. Therefore, the temperature inside the process chamber 50 is set to about 250 to 450 ° C, and preferably, the temperature inside the process chamber 50 is about 250 to 400 ° C. In particular, the internal temperature of the process chamber 50 is set to about 300 ° C in this embodiment. This is because at the temperature of about 300 ° C., the properties of the atomic layer stacks appear best.

In addition, when the pressure inside the process chamber 50 is less than about 0.5 torr, it is not preferable because organometallic precursor reactivity is not easy in a subsequent process. On the other hand, when the inner pressure exceeds about 3.0 torr, it is not preferable because the control of the process for forming the thin film including the metal oxide is not easy. Therefore, the pressure inside the process chamber 50 is set to about 0.5 to 3.0 torr, and preferably to have a pressure of about 0.05 to 2.0 torr. In particular, in this embodiment, the pressure inside the process chamber 50 is set to about 1.0 torr. This is because the atomic layer deposition exhibits the best properties at a pressure of about 1.0 torr.

Subsequently, the organometallic precursor of the present invention is introduced onto the substrate. That is, an organic metal precursor represented by the following Chemical Formula 1 is provided into the chamber 50 having the misleading conditions and the pressure conditions. The organometallic precursor is provided into the chamber using a canister or liquid delivery system (LDS). In this case, the organometallic precursor may be provided over the substrate for about 0.5 to 5 seconds. As one example, the organometallic precursor is vaporized at a temperature of 100-150 ° C. in a liquid delivery system and provided into the chamber 50 for about 1 second.

As a result, the first portion 12 of the organometallic precursor is chemisorbed onto the substrate 10, and the second portion 14 except for the first portion 12 of the hafnium precursor is the first portion 12. Physically adsorbed by 12) may have a loose coupling force or may float in the chamber 50. In addition, some of the hafnium precursor chemisorbed on the substrate may be thermally decomposed by heat in the chamber. Thus, the central metal of the organometallic precursor is chemisorbed on the substrate and a portion of the ligand bound to the central metal may be separated from the central metal.

Hereinafter, an organometallic precursor represented by the following chemical formula will be described in detail.

R ₃ -N = M (N (R ₁ ) (R ₂ )) _{2 ------------------------} [Formula]

In the above formula, R1 to R3 are each independently hydrogen or an alkyl group having 1 to 5 carbon atoms, M is titanium (Ti), zirconium (Zr) or hafnium (Hf). As an example, each of R1 to R3 may independently include a methyl group, an ethyl group, a propyl group, a tertiary butyl group, and the like.

The organometallic precursor represented by the above formula may be tert-butylimido bismethylethylaminohalfnium ((t-BuN) Hf (N (CH ₃ ) (C ₂ H ₅ )) ₂ ) or tert-butylimido bismethylethyl Aminozirconium ((t-BuN) Zr (N (CH ₃ ) (C ₂ H ₅ )) ₂ ).

The organometallic precursor is in a liquid state at room temperature, and is vaporized at a temperature of about 60 to 95 ° C. to have a gaseous state. The organometallic precursor has a saturated vapor pressure of about 1 Torr to 5 torr when vaporized in the gaseous state in the canister.

As an example, the gaseous organometallic precursor may contain the organometallic precursor in a liquid state inside a canister and generate an inert gas bubble while heating the organometallic precursor in a liquid state at a temperature of about 60 to 95 ° C. Can be formed. As a result, a gaseous organometallic precursor is produced in the canister. In this case, the organometallic precursor is generated until the gaseous organometallic precursor formed in the canister is saturated.

The organometallic precursor of the gaseous state represented by the above formula has a saturated vapor pressure of about 1 to 3 torr when heated to a temperature of about 65 to 75 ° C. in the canister. In addition, when heated to a temperature of about 85 to 95 ℃ in the canister has a saturated steam pressure of about 3 to 5 torr. That is, the organometallic precursor represented by the above chemical formula not only has a higher saturation vapor pressure than the hafnium precursor (TEMAH) used in the prior art but also has a high reactivity with the oxidizing agent. The organometallic precursor is a hafnium precursor or a zirconium precursor.

Here, being able to form a gaseous organometallic precursor having a high saturation vapor pressure not only facilitates the formation of a gaseous organometallic precursor, but also supplies the organometallic precursor into the process chamber to form the thin film. That means you can shorten the time it takes. In addition, it means that the amount of the carrier gas provided with the organometallic precursor in the gaseous state provided into the process chamber is reduced, and the amount of inflow (volume) of the organometallic precursor provided into the process chamber is reduced.

Therefore, by applying the organometallic precursor represented by the above formula, it is possible to easily manufacture a thin film having a high dielectric constant compared to the conventional thin film and good leakage current as well as to reduce the process time for forming a thin film. In addition, the throughput of the semiconductor manufacturing process can be finally increased. Hereinafter, the organometallic precursor will be described as a zirconium precursor.

Referring to FIG. 2, an inert gas that is a purge gas is provided into the process chamber 50. Argon gas, nitrogen gas, etc. are mentioned as an example of the said inert gas. At this time, the purge gas is provided for about 1 to 30 seconds. In this embodiment, the purge gas is provided for about 30 seconds.

As such, by providing a purge gas into the process chamber 50, the second portion 14 that is drift in the chamber 50 or physically adsorbed to the first portion 12 is removed. As a result, zirconium precursor molecules 12a remain on the substrate 10 as the chemisorbed first portion 12.

Alternatively, instead of providing the purge gas, the inside of the process chamber 50 may remain in the process chamber 50 or drift in the process chamber 50 even if the vacuum is maintained for about 1 to 30 seconds. It is possible to remove the physically adsorbed second portion 14. As another embodiment, the purge gas and the vacuum purge may be performed together to remove the second part 14 that is drift in the process chamber 50 or physically adsorbed to the first part 12. .

Referring to FIG. 3, an oxidant 16 including oxygen is provided into the chamber 50. Examples of the oxidant 16 include O ₃ , O ₂ , H ₂ O, plasma O ₂ , remote plasma O ₂ , and the like. It is preferable to use these individually, and you may mix and use two or more as needed. The oxidant 16 is then provided for about 0.5 to 5 seconds. In this embodiment, O ₃ is provided as the oxidant 16 for about 2 seconds.

As such, by providing the oxidant 16, the oxidant 16 chemically reacts with the zirconium precursor molecules 12a, which is the first portion 12 of the reactant material chemisorbed onto the substrate 10. Zirconium precursor molecules 12a are oxidized.

Referring to FIG. 4, a purge gas is provided into the chamber 50. The type and provision time of the purge gas are the same as described with reference to FIG. 2. As such, by providing the purge gas into the chamber 50, the oxidant 16 which is not chemically reacted is removed from the process chamber 50.

As a result, a solid material 18 including zirconium oxide is formed on the substrate 10.

Referring to FIG. 5, the processes described with reference to FIGS. 1 to 4 are repeated at least once. As a result, a thin film 20 made of a stack of solid materials 18 is formed on the substrate 10. In this case, the thin film 20 includes zirconium oxide. In addition, the thickness of the thin film 20 is adjusted according to the number of repetitions of the processes.

According to the present exemplary embodiment, the thin film 20 including zirconium or hafnium oxide is formed by using a zirconium precursor or a hafnium precursor having a chemical formula 1 as described above and having a saturated vapor pressure higher than that of a conventional precursor. Thus, the thin film 20 has a high dielectric constant and good leakage current characteristics.

As another example of the thin film formation, unlike the atomic layer deposition process in which the zirconium precursor and the oxidant are separately provided, the thin film may be formed by chemical vapor deposition, in which the gaseous zirconium precursor and the oxidant are simultaneously injected into the process chamber to form a thin film. .

Here, the formation of the thin film made of the solid material simultaneously injects the zirconium precursor and the oxidant in a gaseous state onto the substrate located in the process chamber. Subsequently, the zirconium precursor and the oxidant simultaneously injected are chemically reacted on the substrate to form zirconium oxide. Subsequently, the formed zirconium oxide is chemisorbed on the surface of the substrate to form a solid material on the substrate. Thereafter, zirconium oxide is continuously chemisorbed on the solid material for a predetermined time to form a thin film. The thickness of the thin film is adjusted according to the chemical vapor deposition time.

Thin Film Manufacturing Method 2

6 is a flowchart illustrating a method of forming a thin film according to Embodiment 2 of the present invention.

Referring to FIG. 6, the substrate is placed in the chamber (step S110). At this time, the temperature in the chamber is set to about 250 to 450 ℃, preferably set to a temperature of about 250 to 400 ℃, more preferably set to about 300 ℃.

Then, a first reactant is introduced onto the substrate (step S120). That is, the organometallic precursor represented by the following chemical formula into the chamber. The organometallic precursor includes a hafnium precursor and a zirconium precursor. As an example, the hafnium precursor is tert-butylimido bismethylethylaminohafnium ((t-BuN) Hf (N (CH ₃ ) (C ₂ H ₅ )) ₂ ) and the zirconium precursor is tert-butylimide Bismethylethylaminozirconium ((t-BuN) Zr (N (CH ₃ ) (C ₂ H ₅ )) ₂ ). Preferably, the first reactant is introduced into the top of the substrate for about 0.5 to 3 seconds. In particular, the first reactant material is more preferably introduced into the top of the substrate for about 1 second by a liquid delivery system. As such, the first portion of the tertiary butylimido bismethylethylaminozirconium is chemisorbed onto the substrate by introducing the tertiary butylimido bismethylethylaminozirconium as the first reaction material to the top of the substrate. And the second portion is physically adsorbed.

Subsequently, argon gas is introduced into the upper portion of the substrate to first purge the substrate (step S130). The argon gas is a purge gas, preferably introduced into the upper portion of the substrate for about 0.5 to 3 seconds. In particular, the argon gas is more preferably introduced into the top of the substrate for about 1 second. As such, the second portion of the tertiary butylimido bismethylethylaminozirconium physically adsorbed on the substrate is removed by introducing the argon gas onto the substrate. That is, the hydrocarbon (CH) radicals contained in the tertiary butylimido bismethylethylamino zirconium are desorbed from the substrate by the argon gas. However, even when the argon gas is introduced into the upper portion of the substrate, zirconium (Zr) contained in the tertiary butylimido bismethylethylaminozirconium remains chemisorbed on the substrate. In addition to introducing the argon gas, the hydrocarbon radicals are desorbed from the substrate even if the inside of the chamber is kept in vacuum for about 2 to 3 seconds.

Subsequently, an oxidant containing oxygen is introduced into the upper portion of the substrate (step S140). Examples of the oxidizing agent include O ₃ , H ₂ O, H ₂ O ₂ , CH ₃ OH, C ₂ H ₅ OH, and the like. It is preferable to use these alone, but you may mix and use two or more as needed. In this example, O ₃ is used as the oxidizing agent. And, as the oxidizing agent, O ₃ is preferably introduced to the top of the substrate for about 1 to 5 seconds. In particular, the O ₃ is more preferably introduced to the top of the substrate for about 3 seconds. In this manner, the zirconium chemisorbed on the substrate is oxidized by introducing the oxidant to the upper portion of the substrate. As a result, a first solid material containing zirconium oxide is formed on the substrate.

Subsequently, the substrate is purged second using argon gas (step S150). The argon gas is a purge gas, preferably introduced into the upper portion of the substrate for about 1 to 5 seconds. In particular, the argon gas is more preferably introduced into the top of the substrate for about 3 seconds. As such, the oxidant remaining in the chamber is removed by introducing the argon gas to the top of the substrate.

Accordingly, a first solid material containing zirconium oxide is formed on the substrate, and the tertiary butylimido is repeatedly introduced with bismethylethylaminozirconium, an argon gas, an oxidant, and an argon gas. In the case of carrying out, the first solid material containing the zirconium oxide may be formed of a solid thin film containing a zirconium oxide having a desired thickness, that is, a zirconium oxide film.

Subsequently, a second reaction material is introduced onto the first solid material 140 (step S160). The second reactant is an aluminum precursor. Examples of the aluminum precursor include a trimethyl aluminum (TMA) precursor, a tri ethyl aluminum (TEA) precursor, a tri isobutyl aluminum precursor, and the like. More preferably, the second reactant is introduced into the top of the first solid phase for about 1 second. As such, by introducing TEA as the second reactive material onto the first solid material, the first portion of the TMA is chemisorbed on the first solid material and the second portion is physically adsorbed.

Subsequently, the substrate is purged third using argon gas (step S170). The argon gas is a purge gas, more preferably introduced into the top of the first solid material for about 1 second. As such, introducing the argon gas to the top of the first solid material removes the second portion of TEA, the aluminum precursor physically adsorbed on the first solid material.

Subsequently, an oxidant is introduced into the first solid material (step S180). The oxidant is the same as the oxidant described in step S140. Thus, O ₃ is selected as the oxidant and introduced to the top of the first solid material for about 3 seconds. As such, aluminum (Al) chemisorbed on the first solid material is oxidized by introducing the oxidant to the upper portion of the first solid material. As a result, a second solid material containing aluminum oxide is formed on the first solid material.

Subsequently, the substrate is purged fourth using argon gas (step S190). The argon gas is a purge gas, which is more preferably introduced into the upper portion of the second solid material for about 3 seconds. As such, the oxidant remaining in the chamber is removed by introducing the argon gas to the top of the second solid material.

As a result, a second solid material 180 containing aluminum oxide is formed on the first solid material, and the TEA, the argon gas, the oxidizing agent, and the argon gas are repeatedly introduced. The second solid material containing the aluminum oxide may be formed of a solid thin film containing an aluminum oxide having a desired thickness, that is, an aluminum oxide film.

And by appropriately controlling each of the number of times of forming the first solid material containing zirconium oxide using the zirconium precursor and the number of times of forming the second solid material containing aluminum oxide using the aluminum precursor as desired. A composite metal oxide film containing zirconium-aluminum-oxide having a composition ratio of zirconium and aluminum is formed (step S200).

In another embodiment, the number of times of forming the first solid material containing hafnium-oxide using the hafnium precursor instead of the zirconium precursor and the number of times of forming the second solid material containing aluminum-oxide using the aluminum precursor, respectively By appropriately adjusting, a solid thin film containing zirconium-aluminum-oxide having a desired hafnium-aluminum composition ratio can be obtained.

Manufacturing method of gate structure

7 to 10 are cross-sectional views illustrating a method of manufacturing a gate structure in accordance with an embodiment of the present invention.

Referring to FIG. 7, a substrate isolation process is performed to separate the substrate 100 into an active region and a field region 102. Here, examples of the substrate 100 include a silicon substrate, a silicon-on-insulator (SOI) substrate, and the like.

Subsequently, a gate insulating film 104 is formed on the substrate 100. In this case, the gate insulating layer 104 should be able to sufficiently reduce the leakage current generated between the gate electrode and the channel while maintaining a thin equivalent oxide film thickness. Therefore, in this embodiment, a thin film containing a metal oxide is formed as the gate insulating film 104.

As an example, the thin film may include hafnium-oxide or zirconium-oxide and may be formed by applying the atomic layer deposition method according to the thin film manufacturing method 1. As another example, the thin film may include zirconium-aluminum oxide, and may be formed by applying an atomic layer deposition process according to the thin film manufacturing method 2.

The organometallic precursor applied to the atomic layer deposition process is represented by the following formula.

R ₃ -N = M (N (R ₁ ) (R ₂ )) _{2 ------------------------} [Formula]

In the above formula, R1 to R3 are each independently hydrogen or an alkyl group having 1 to 5 carbon atoms, M is titanium (Ti), zirconium (Zr) or hafnium (Hf). As an example, each of R1 to R3 may independently include a methyl group, an ethyl group, a propyl group, a tertiary butyl group, and the like. The organometallic precursor represented by the above formula is tertiary butylimido bismethylethylaminohalfnium ((t-BuN) Hf (N (CH ₃ ) (C ₂ H ₅ )) ₂ ) or tertiary butylimido bismethylethyl Aminozirconium ((t-BuN) Zr (N (CH ₃ ) (C ₂ H ₅ )) ₂ ). The organometallic precursor is in a liquid state at room temperature, and vaporized at a temperature of about 60 to 95 ° C. to have a gaseous state. The organometallic precursor is characterized by having a saturated vapor pressure of about 1 Torr to 5 torr when vaporized in the gaseous state in the canister.

Detailed description of the thin film manufacturing method 1 and 2 will be omitted to avoid duplication.

In this embodiment, it is preferable to apply the hafnium precursor or zirconium precursor to the atomic layer deposition process to form a gate insulating film 104 made of zirconium oxide on the substrate 100. A silicon oxide film (not shown) having a thickness of about 5 GPa may be further formed on the gate insulating film 104. In this case, the silicon oxide film may be formed by in-situ after forming the gate insulating film 104 including hafnium oxide.

Referring to FIG. 8, a gate conductive layer 110 is formed on the gate insulating layer 104. The gate conductive layer 110 has a structure in which a polysilicon layer 106 and a metal silicide layer 108 such as a tungsten silicide layer are sequentially stacked. In addition, a capping insulating layer 112 including a silicon oxide material may be formed on the gate conductive layer 110.

Referring to FIG. 9, the capping insulation layer 112, the gate conductive layer 110, and the gate insulation layer 104 formed on the substrate 100 are sequentially patterned. As a result, a gate structure 115 including a gate insulating film pattern 104a, a gate conductive film pattern 110a, and a capping insulating film pattern 112a is formed on the substrate 100. Patterning for forming the gate structure 115 is accomplished by a photolithography process.

Referring to FIG. 10, a source / drain region 120 is formed on a surface portion of the substrate 115 adjacent to the gate structure 115. The source / drain region 120 is formed before the gate insulating layer 104 is formed or after the spacer 114 is formed in the gate structure 115.

As such, the gate insulating film pattern made of hafnium oxide or zirconium oxide, which is a material having a high dielectric constant included in the gate structure, sufficiently reduces the leakage current generated between the gate conductive film pattern and the substrate while maintaining a thin equivalent insulating film thickness. Can be. In addition, since the time required for manufacturing the gate insulating film formed of the metal precursor represented by the chemical formula is reduced, the gate structure can be formed more quickly.

Method of manufacturing a capacitor

11 to 14 are cross-sectional views illustrating a method of manufacturing a capacitor according to an embodiment of the present invention.

Referring to FIG. 11, after forming a substrate on which an interlayer insulating film 124 including a contact hole 126 exposing a contact plug is provided, a lower electrode conductive film 132 electrically connected to the contact plug 122 is formed. Form. In particular, when the semiconductor device formed using the substrate 130 is a DRAM, a gate structure 115, a bit line (not shown), and a contact plug 122 having a spacer 114 formed on the substrate 130 may be provided. It is preferable that semiconductor structures such as the like be formed.

 The conductive film 132 continuously forms the lower electrode conductive film 132 on the side and bottom of the contact hole 126. The conductive layer 132 may be formed using a material such as polysilicon, titanium nitride, tantalum nitride, tungsten nitride, rudenium, or the like. Although the above materials are preferably used alone, two or more of them may be mixed and used in some cases.

Referring to FIG. 12, a lower electrode 140 electrically connected to the contact plug 122 is formed. Referring to the method of forming the lower electrode 140, after forming a sacrificial film (not shown) on the resultant having the conductive film 132, the sacrificial film is removed until the surface of the conductive film is exposed. . Subsequently, when the conductive layer 132 formed on the surface of the interlayer insulating layer 124 is removed, the lower electrode 140 existing on the side and bottom of the contact hole 126 is formed. Subsequently, the lower electrode 140 is completed by completely removing the sacrificial film (not shown) and the interlayer insulating film 124 remaining in the contact hole 126. In particular, the lower electrode 140 has a cylindrical shape in which the width of the inlet is wider than that of the bottom surface.

Referring to FIG. 13, a dielectric film 150 is formed on the surface of the lower electrode 140. Here, the dielectric film 150 should have a thin equivalent oxide film thickness and high dielectric constant while sufficiently reducing the leakage current generated between the lower electrode 140 and the upper electrode. Therefore, in the present embodiment, a thin film made of a metal oxide is formed as the dielectric film 150.

As an example, the thin film may include hafnium-oxide or zirconium-oxide and may be formed by applying the atomic layer deposition method according to the thin film manufacturing method 1. As another example, the thin film may include zirconium-aluminum oxide, and may be formed by applying the atomic layer deposition method according to the thin film manufacturing method 2. The organometallic precursor is tertiary butylimido bismethylethylaminohafnium ((t-BuN) Hf (N (CH ₃ ) (C ₂ H ₅ )) ₂ ) or tertiary butylimido bismethylethylaminozirconium ( (t-BuN) Zr (N (CH ₃ ) (C ₂ H ₅ )) ₂ ).

In the present embodiment, it is preferable to form the dielectric film 150 made of hafnium oxide on the lower electrode 140 by applying the organometallic precursor to an atomic layer deposition process.

Referring to FIG. 14, after the dielectric film 150 is formed, the dielectric film 150 is heat treated to remove contaminants formed on the dielectric film 150 or mixed in the dielectric film 150 and to recover oxygen defects. . The heat treatment process mainly performs ultraviolet ozone (UV-O ₃ ) treatment, plasma treatment and the like.

The upper electrode 160 is formed on the surface of the dielectric film 150. The upper electrode 160 is formed using a material such as polysilicon, titanium nitride, tantalum nitride, tungsten nitride, rudenium, or the like. It is preferable to use the above materials alone, but in some cases, two or more of them may be used in combination.

Accordingly, the capacitor 170 including the lower electrode 140, the dielectric film 150 made of hafnium oxide, and the upper electrode 160 is formed on the substrate 130.

As described above, in the present embodiment, a solid thin film including hafnium oxide, which is a material having a high dielectric constant, is used as the dielectric film. Therefore, the dielectric film of this embodiment can maintain the thickness of the thin equivalent dielectric film.

Precursor Vapor Pressure Assessment 1

In the case of forming a thin film made of hafnium oxide, tertiary butylimido bismethylethylaminohafnium (A) and tetraethylmethylaminohafnium (TEMAH) saturation vapor pressures, which were applied as hafnium precursors, were measured. The vapor pressure is measured by changing the saturation vapor pressure with temperature when the hafnium precursors are heated to form a gas state after the hafnium precursors are accommodated in a canister having the same space 10L. That is, the change in the canister internal pressure for 20 ° C. to 90 ° C. was measured and the result is shown in the graph of FIG. 15. Here, the saturated vapor pressure of the hafnium precursors is equal to the internal pressure of the canister. 15 is a graph showing the saturation vapor pressure change of hafnium precursors with temperature change.

Referring to FIG. 15, as shown in the graph, the tertiary butylimido bismethylethylaminohafnium (A), which is the hafnium precursor of the present invention, has a pressure of about 1 torr, that is, a pressure inside the canister when heated to 72 ° C. It can be seen that it has a pressure of 1 torr. Also, it can be seen that tertiary butylimido bismethylethylaminohafnium (A) has a pressure of about 3 torr, that is, a pressure inside the canister, when heated to 90 ° C. On the other hand, the conventional hafnium precursor TEMAH has a pressure of about 0.4 torr when heated to 72 ° C, that is, a pressure inside the canister about 0.4 torr, and a pressure of about 1 tor when heated to 90 ° C It can be seen that the internal pressure has a pressure of about 1 torr.

As a result, the tertiary butylimido bismethylethylaminohafnium (A) used for forming the thin film made of hafnium oxide has a characteristic of having a vapor pressure of about 2 times or more than TEMAH. For this reason, when the tertiary butylimide also forms a thin film using bismethylethylaminohafnium (A), the process time for forming the thin film can be reduced. In addition, the throughput of the semiconductor manufacturing process can be finally increased.

Precursor Vapor Pressure Assessment 2

In the same manner as the precursor vapor pressure evaluation 1, the change of the saturated vapor pressure according to the temperature of the tertiary butylimido bismethylethylamino zirconium (B) as the zirconium precursor was measured. The results are shown in the graph of FIG. Here, the saturated vapor pressure of the zirconium precursor is equal to the internal pressure of the canister. FIG. 16 is a graph illustrating a change in saturated vapor pressure of a zirconium precursor with temperature change. FIG.

Referring to FIG. 16, as shown in the graph, tertiary butylimido bismethylethylaminozirconium (B), which is a zirconium precursor of the present invention, has a pressure of about 1 torr, that is, a pressure inside the canister when heated to about 72 ° C. It can be seen that it has a pressure of about 1 torr. In addition, it can be seen that tertiary butylimido bismethylethylaminozirconium (B) has a pressure of about 2.7 torr, that is, a pressure inside the canister, when heated to about 90 ° C. Thus, when the tertiary butylimide also forms a thin film using bismethylethylaminozirconium (B), the process time for forming the thin film can be reduced. In addition, the throughput of the semiconductor manufacturing process can be finally increased.

Vaporization rating

FIG. 17 is a thermogravimetric analysis (TAG, Thermo) of organometallic precursors (t-BuN) Hf (N (Me) (Et)) ₂ , TEMAH and (t-BuN) Zr (N (Me) (Et)) ₂ . Gravimetric Analysis) is a graph showing the results. The thermogravimetric analysis method records the weight change of the sample according to time and temperature while maintaining the temperature of the sample at a constant rate or maintaining an isothermal temperature. ) To analyze.

Referring to FIG. 17, each of the organometallic precursors (t-BuN) Hf (N (Me) (Et)) ₂ , TEMAH and (t-BuN) Zr (N (Me) (Et)) ₂ , respectively The weight loss of each precursor was measured while rising from room temperature to about 400 ° C. at 5 ° C. per minute. As a result, the weight loss of the (t-BuN) Hf (N (Me) (Et)) ₂ , TEMAH and (t-BuN) Zr (N (Me) (Et)) ₂ is abruptly between about 130 and 220 ° C. Was found to occur. That is, the (t-BuN) Hf (N (Me) (Et)) _2, and (t-BuN) Zr (N (Me) (Et)) ₂ and TEMAH show the behavior of vaporizing from a liquid state to a gaseous state. Could confirm. Therefore, in this evaluation, (t-BuN) Hf (N (Me) (Et)) ₂ and (t-BuN) Zr (N (Me) (Et)) ₂ It can be seen that the metal precursor is suitable for use in the atomic layer deposition process as in the conventional TEMAH.

Leakage current evaluation of capacitors 1

After performing an atomic layer deposition process using a (t-BuN) Hf (N (Me) (Et)) ₂ precursor to form a hafnium oxide film applied to a cell capacitor, the leakage current of the cell capacitor including the hafnium oxide film is measured. It was. The hafnium oxide film has a thickness of about 13.7 kW.

18 is a graph showing leakage current characteristics of a capacitor to which a hafnium-oxide film of the present invention is applied as a dielectric film.

Referring to FIG. 18, a cell capacitor including a hafnium oxide film formed using the (t-BuN) Hf (N (Me) (Et)) ₂ precursor has a low value of about 1.00E-15A / cm 2 at a voltage of 0.5V. Leakage current is shown. In addition, a low leakage current of about 1.00E-13A / cm 2 was exhibited at a voltage of 1.3V. It was confirmed that the cell capacitor including the hafnium-oxide film has good leakage current characteristics and dielectric constant (cell cap) characteristics. That is, it was confirmed that the (t-BuN) Hf (N (Me) (Et)) ₂ precursor can be used in a semiconductor manufacturing apparatus.

Leakage Current Evaluation of Capacitors 2

After performing an atomic layer deposition process using (t-BuN) Zr (N (Me) (Et)) ₂ and trimethyl aluminum (TMA) precursor to form a composite metal oxide film applied to a cell capacitor, the composite metal oxide film is included. The leakage current of the cell capacitor was measured. The composite metal oxide film has a structure in which 70 kV of the first zirconium oxide film (ZrO ₂ ), 4 kW of the aluminum oxide film (Al ₂ O ₃ ), and 40 kW of the second zirconium oxide film (ZrO ₂ ) are stacked.

19 is a graph showing leakage current characteristics of a capacitor formed using the zirconium-aluminum oxide film of the present invention.

Referring to FIG. 19, a cell capacitor including a zirconium-aluminum oxide film formed using the (t-BuN) Zr (N (Me) (Et)) ₂ precursor is about 1.00E-17A / cm 2 at a voltage of 0.4V. It showed a low leakage current. In addition, a low leakage current of about 1.00E-16A / cm 2 was exhibited at a voltage of 2.1V. It was confirmed that the cell capacitor including the zirconium-aluminum oxide film has very good leakage current characteristics and dielectric constant (cell cap) characteristics. That is, it was confirmed that the (t-BuN) Zr (N (Me) (Et)) ₂ precursor may have excellent characteristics when used in a semiconductor manufacturing apparatus.

Step coating property of metal oxide film

TABLE 1

Process conditions First reactant Second reactant Chamber temperature Canist Temperature Carrier Gas (t-BuN) Zr (N (Me) (Et)) ₂ O ₃ 340 ℃ 80 ℃ 1000sccm TEMAZ O ₃ 320 ℃ 80 ℃ 1000sccm

Zirconium-oxide films were formed by performing an atomic layer deposition process applying the conditions of Table 1 to a cylinder structure having an aspect ratio of about 10: 1. Then, step coverage of the formed zirconium oxide films was measured. The results are shown in the graph of FIG. The step coverage is a ratio of the thickness of the zirconium oxide film deposited on the upper surface of the structure and the thickness of the zirconium oxide film deposited on the bottom surface of the hole included in the structure.

20 is a graph showing step coverage of zirconium oxide films according to the present invention.

Referring to FIG. 20, the zirconium oxide film formed of the (t-BuN) Zr (N (Me) (Et)) ₂ precursor has a high step coverage of about 87%, whereas the TEMAZ (tetraethylmethylamide zirconium) It was confirmed that the zirconium oxide film formed of the precursor has a low step coverage of about 64%. Accordingly, it can be seen that the (t-BuN) Zr (N (Me) (Et)) ₂ precursor can be sufficiently used in the process of forming a cylindrical capacitor dielectric film.

The organometallic precursor represented by the above formula applied when forming a thin film including the metal oxide according to the present invention has not only a higher saturated vapor pressure than the metal precursors (TEMAH, TEMAZ) used in the prior art but also a high reactivity with the oxidizing agent. . Therefore, it is possible to improve the throughput and process characteristics of the step cover during the thin film manufacturing process. In addition, the thin film formed of the metal precursor has good leakage current characteristics. Therefore, the thin film can be easily applied to the gate insulating film of the gate structure, the dielectric film of the capacitor, and the like, and as a result, the electrical reliability of the semiconductor device can be obtained.

As described above, the present invention has been described with reference to the embodiments of the present invention, but those skilled in the art will variously modify the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. And can be changed.

Claims (14)

Providing an organometallic precursor onto a substrate having a saturated vapor pressure of 1 Torr to 5 torr and heated to a temperature of 60 to 95 ° C. in a canister; Providing an oxidant comprising oxygen for oxidizing the organometallic precursor to the top of the substrate; And And chemically reacting the organometallic precursor provided on the substrate with the oxidant to form a thin film including a metal-oxide on the surface of the substrate. [Formula] R ₃ -N = M (N (R ₁ ) (R ₂ )) ₂ (In the above formula, R ₁ to R ₃ are each independently hydrogen or an alkyl group having 1 to 5 carbon atoms, M is zirconium (Zr) or hafnium (Hf)) The method of claim 1, wherein the organometallic precursor is tert-butylimido bismethylethylaminohalfnium (t-BuN) Hf (N (CH ₃ ) (C ₂ H ₅ )) ₂ or tert-butylimido bismethylethyl Amino zirconium (t-BuN) Zr (N (CH ₃ ) (C ₂ H ₅ )) _{2 It} is a thin film forming method. The method of claim 1, wherein the organometallic precursor is formed by heating a liquid organometallic precursor to a temperature of 75 to 85 ° C. in a canister and is in a gas state having a saturated vapor pressure of 3 Torr to 5 torr. Way. The method of claim 1, wherein the organometallic precursor is supplied onto the substrate with at least one carrier gas selected from the group consisting of argon gas, nitrogen gas, and helium gas. The method of claim 1, further comprising: first purging the substrate by using a purge gas after the organometallic precursor is provided, and second purging the substrate by using the purge gas after the oxidant is provided. Thin film manufacturing method characterized in that the step of performing further. The method of claim 1, wherein the thin film is formed at a temperature of 250 to 400 ° C. and a pressure of 0.5 to 3.0 torr. The method of claim 1, wherein the organometallic precursor is provided on the substrate by a liquid delivery system, and vaporized at a temperature of 100 to 150 ° C. in the liquid delivery system. . a) introducing an organometallic precursor, represented by the formula below, heated to a temperature of 60 to 95 ° C. as a first reactant, having a saturated vapor pressure of 1 Torr to 5 torr; b) chemisorbing a portion of the metal precursor molecules constituting the organometallic precursor onto the substrate and physically adsorbing the remaining metal precursor molecules except for the portion of the chemisorbed organometallic precursor molecules; c) introducing an oxidant comprising oxygen onto the substrate; d) chemically reacting the molecule of the organometallic precursor chemisorbed on the substrate with the oxidant to form a first solid material containing a metal-oxide on the substrate; e) introducing an organoaluminum precursor, a second reactant material, over the first solid phase material; f) chemisorbing a portion of the aluminum precursor molecules constituting the organoaluminum precursor onto the first solid material and physically adsorbing the remaining aluminum precursor molecules except for the portion of the chemisorbed organoaluminum precursor molecules; g) introducing an oxidant on top of said first solid material; And h) chemically reacting a chemically adsorbed aluminum precursor molecule with said oxidant on said first solid material to form a second solid material containing aluminum-oxide on said first solid material. Thin film formation method for forming a solid thin film containing an oxide. [Formula] R ₃ -N = M (N (R ₁ ) (R ₂ )) ₂ (In the above formula, R1 to R3 are each independently hydrogen or an alkyl group having 1 to 5 carbon atoms, M is zirconium (Zr) or hafnium (Hf)) The method of claim 8, further comprising: removing organometallic precursor molecules physically adsorbed on the substrate; Removing an oxidant that has not reacted with the chemisorbed organometallic precursor molecule; Removing the aluminum precursor molecules physically adsorbed on the substrate; And And removing an oxidant that has not reacted with the chemisorbed aluminum precursor molecule. The method of claim 8, wherein each of a) to d) and e) to h) is repeated at least once. The method of claim 8, wherein a) to h) are repeated at least once. The method of claim 8, wherein the organometallic precursor is tert-butylimido bismethylethylaminohalfnium (t-BuN) Hf (N (CH ₃ ) (C ₂ H ₅ )) ₂ or tert-butylimido bismethylethyl Amino zirconium (t-BuN) Zr (N (CH ₃ ) (C ₂ H ₅ )) _{2 It} is a thin film forming method. Providing an organometallic precursor onto a substrate having a saturated vapor pressure of 1 Torr to 5 torr and heated to a temperature of 60 to 95 ° C. in a canister; Providing an oxidant comprising oxygen for oxidizing the organometallic precursor to the top of the substrate; Chemically reacting the organometallic precursor provided over the substrate with the oxidant to form a gate insulating film including a metal-oxide on a surface of the substrate; Forming a conductive film on the gate insulating film; And And sequentially patterning the conductive film and the gate insulating film to form a gate structure including a gate conductive film pattern and a gate insulating film pattern. [Formula] R ₃ -N = M (N (R ₁ ) (R ₂ )) ₂ In the above formula, R1 to R3 are each independently hydrogen or an alkyl group having 1 to 5 carbon atoms, M is zirconium (Zr) or hafnium (Hf)) Forming a lower electrode on the substrate; Providing an organometallic precursor onto a substrate having a saturated vapor pressure of 1 Torr to 5 torr and heated to a temperature of 60 to 95 ° C. in a canister; Providing an oxidant comprising oxygen for oxidizing the organometallic precursor to the top of the substrate; Chemically reacting the organometallic precursor provided over the substrate with the oxidant to form a dielectric film including a metal-oxide on the lower electrode; And And forming an upper electrode on the dielectric layer. [Formula] R ₃ -N = M (N (R ₁ ) (R ₂ )) ₂ (In the above formula, R1 to R3 are each independently hydrogen or an alkyl group having 1 to 5 carbon atoms, M is zirconium (Zr) or hafnium (Hf))

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