KR100766007B1 - METHOD FOR FORMING HfO2 FILM USING Hf Metal Organic Compound - Google Patents

Abstract

In forming the HfO2 film by the ALD method, an Hf metal organic substance containing Si atoms as the Hf source is used. The HfO ₂ film forming method using the atomic layer deposition method according to the present invention comprises supplying an Hf source into the reactor loaded with a semiconductor substrate to adsorb Hf on the surface of the semiconductor substrate, and supplying a first purge gas into the reactor Purging the unreacted Hf source and the reaction by-product, supplying an oxygen source into the reactor to react with Hf adsorbed on the surface of the semiconductor substrate, and supplying a second purge gas into the reactor to supply the unreacted oxygen source. Purging the reaction by-products with one cycle, the cycle is repeated one or more times to form an HfO ₂ film.

Description

Method for forming hafnium oxide film using hafnium metal organic compound {METHOD FOR FORMING HfO2 FILM USING Hf Metal Organic Compound}

1 is a flowchart illustrating a method of depositing an ALD HfO ₂ film using a hafnium metal organic material according to an embodiment of the present invention.

2A to 2C are gas supply diagrams applied in an ALD HfO ₂ film deposition method using hafnium metal organic material according to a preferred embodiment of the present invention.

The present invention relates to a method for forming a hafnium oxide film (ALD HfO ₂ ) using a hafnium metal organic material, and particularly has excellent step coverage characteristics and uniformity characteristics, and can form a high dielectric constant hafnium oxide film (HfO ₂ ) in a wide temperature range. A hafnium oxide film formation method using a hafnium metal organic material.

Silicon oxide film (SiO ₂ ) and silicon nitride film (SiNx) used in semiconductor devices have been used as gate oxide and capacitor dielectric films for a long time because of their excellent thermal stability, insulation, dielectric property, and chemical resistance. However, since the dielectric constants of the silicon oxide film and the silicon nitride film are relatively low at 3.5 and 7.0, respectively, the thickness of the film must be made very thin in order to secure sufficient capacitance as the size of the device is reduced. However, a problem arises in that the leakage current increases exponentially as the thickness of the silicon oxide film and the silicon nitride film decreases, and therefore, the silicon oxide film and the silicon nitride film cannot be used in a high-integration device. In order to solve this problem, as a material having a high dielectric constant to replace the silicon oxide film and silicon nitride film, tantalum oxide film (Ta ₂ O ₅ ), titanium oxide film (TiO ₂ ), zirconium oxide film (ZrO ₂ ), hafnium oxide film (HfO ₂₎ In addition, a method using a ferroelectric BST or the like has been proposed. However, a tantalum oxide film (Ta ₂ O ₅ ), a titanium oxide film (TiO ₂ ), a zirconium oxide film (ZrO ₂ ), and a ferroelectric BST material are formed on the silicon contact surface. It is difficult to use the gate oxide film and the capacitor dielectric film because of poor interfacial stability or poor temperature stability due to subsequent processes, or high leakage current. In order to solve this problem, a method of using a hafnium oxide film having a high dielectric constant of 25 has been proposed as a dielectric film to replace the silicon oxide film and the silicon nitride film. In order to use a hafnium oxide film as a gate oxide film, it is required to be deposited very thinly and precisely, and to use it as a capacitor dielectric film, excellent step coverage is required. In order to satisfy these conditions, the hafnium oxide film should be deposited by an atomic layer deposition method. Until now, it was possible to form a thin film while controlling the thickness very precisely at a temperature of 250 to 500 ° C.

However, this conventional hafnium oxide film process uses a solid source of HfCl ₄ which is a hafnium halide compound. Since HfCl ₄ is a solid source, the vapor pressure is very low, and there are many problems in supplying the source. First, there is a problem that the source supply time is very long because the amount of the source supplied is very small due to the low vapor pressure. The result is an increase in overall process time. Second, there is a problem that the step coverage is poor in the manufacturing process of the capacitor structure having a high step ratio. Finally, in order to compensate for the low vapor pressure of the solid source, the temperature of the source supply must be kept very high, which makes it difficult to maintain the temperature of the supply uniformly.

In order to solve the above problems, by forming a hafnium oxide film using hafnium metal organic material of a high vapor pressure liquid source, it has excellent step coverage and uniformity characteristics even at a short process time and low temperature of the source supply, very precise and thin thickness It is an object of the present invention to provide a method for forming a hafnium oxide film using a hafnium metal organic material capable of forming a hafnium oxide film.

HfO ₂ film forming method using a hafnium metal organic material according to the present invention comprises the steps of adsorbing the hafnium metal organic material on the surface of the semiconductor substrate by supplying a hafnium metal organic liquid source containing Si atoms into the reactor loaded with a semiconductor substrate; Supplying a first purge gas into the reactor to purge the unreacted Hf source and the reaction by-product, and supplying an oxygen source into the reactor to react with the hafnium metal organic material adsorbed on the surface of the semiconductor substrate. Supplying a purge gas into the reactor to purge the unreacted oxygen source and the reaction by-product is one cycle, and the cycle is repeated one or more times to form an HfO ₂ film.

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

1 is a process flowchart showing the process sequence of the HfO ₂ film deposition method using the atomic layer deposition method according to the present invention.

Referring to FIG. 1, in the HfO ₂ film deposition method according to the present invention, a substrate for forming a semiconductor device is first loaded into a reactor of a thin film forming apparatus (S100). The temperature of the substrate is then preheated to a process temperature suitable for HfO ₂ film deposition, ie 100-600 ° C., using a heater installed in the reactor. At this time, the preheating of the substrate is performed at the same time as the exhaust from the reactor, the pressure in the reactor is maintained at 10 Torr or less (step S110).

When the substrate is raised to a desired process temperature, an HfO ₂ film is formed on the substrate by an atomic layer deposition method.

To this end, first, a first reactant, which is a hafnium metal organic material containing Si atoms as an Hf source, is supplied onto the substrate to form a chemisorbed layer of the first reactant on the substrate (step S120). Here, the first reactant hafnium metal organic source is Hf {N [Si (CH ₃ ) ₃ ] ₂ } ₄ containing Si atoms, Hf {N [Si (C ₂ H5) ₃ ] ₂ } ₄ , Hf [ It is preferably one selected from NHSi (CH ₃ ) ₃ ] ₄ and Hf [NHSi (C ₂ H ₅ ) ₃ ] ₄ . When supplying the first reactant, the process pressure in the reactor is maintained at 10 Torr or less, preferably 0.5 to 3.0 Torr. When supplying the first reactant, the reactor may be supplied with an inert gas such as argon (Ar) or nitrogen (N 2).

Then, the unreacted hafnium metal organic matter remaining without reaction is removed by reaction (S130). To this end, an inert gas such as argon is used to carry out a purge process or an evacuation process at a pressure lower than the pressure at the time of supplying the first reactant. In addition, in order to remove the reaction by-products, a series of processes combining the purge process and the exhaust process may be performed. For example, after performing a purge process using an inert gas first, an exhaust process may be performed, and conversely, it is also possible to perform a purge process after performing an exhaust process.

Next, a second reactant, which is an oxygen source containing O or H, is supplied onto the chemisorption layer of the first reactant to chemically react the chemisorption layer of the first reactant with the second reactant (step S140). Here, the second reactant, which is the oxygen source, is preferably any one selected from H ₂ O, O ₃ , O _2, and H ₂ O ₂ . When supplying the second reactant, the process pressure in the reactor is maintained at 10 Torr or less, preferably 0.5 to 3.0 Torr. When the first reactant is supplied, an inert gas such as argon (Ar) or nitrogen (N ₂ ) may be supplied into the reactor.

 Next, the by-products generated after the reaction with the unreacted oxygen source remaining without reaction are removed (step S150). To this end, an inert gas such as argon is used to perform a purge process or an evacuation process at a pressure lower than the pressure at the time of supply of the second reactant. In addition, in order to remove the reaction by-products, a series of processes combining the purge process and the exhaust process may be performed. For example, after performing a purge process using an inert gas first, an exhaust process may be performed, and conversely, it is also possible to perform a purge process after performing an exhaust process.

Steps S120 to S150 are repeated a plurality of times until an HfO ₂ film having a desired thickness is formed on the substrate. Once the HfO ₂ film is formed on the substrate to a desired thickness, an evacuation process from the reactor is performed to remove deposition byproducts remaining in the chamber. At this time, no gas is supplied into the reactor. Thereafter, the substrate is unloaded from the reactor (step S160).

As described above, in the HfO ₂ film deposition formation according to the present invention, a hafnium metal organic material containing Si atoms is used as the hafnium source. Therefore, the hafnium metal organic material, which is a liquid source as the hafnium source, has a high vapor pressure, thereby lowering the temperature of the source supply portion, thereby improving the stability of the equipment, and improving the deposition rate by a short process time. In addition, excellent step coverage and thickness uniformity of the thin film can be improved.

The HfO ₂ film formed by the method described with reference to FIG. 1 may be variously applied in the manufacturing process of the highly integrated semiconductor device. For example, the HfO ₂ film may be configured as a gate dielectric film when forming a gate on a semiconductor substrate. In addition, the HfO ₂ film may be configured as a capacitor dielectric film when the capacitor is formed on the semiconductor substrate.

2A to 2C illustrate a method of performing APR HfO ₂ film deposition using hafnium metal organic material according to a preferred embodiment of the present invention, in which only a purge process is performed and a purge process is not performed. If not, and the gas supply diagram when the purge process and the exhaust process alternately.

FIG. 2A illustrates an embodiment that proceeds in the order of a first reactant feed consisting of Hf metal organics, a purge, a second reactant feed consisting of an oxygen source, and a purge, and FIG. 2B illustrates a first reactant feed, exhaust, and a second reactant. An embodiment proceeds in the order of supply and exhaust. FIG. 2C also shows an embodiment that proceeds in the order of first reactant feed, purge, evacuation, second reactant feed, purge and evacuation. Various combinations of purge and exhaust are possible as shown in FIGS. 2A-2C.

In the method of forming a hafnium oxide film using the hafnium metal organic material according to the present invention, when hafnium metal organic material, which is a liquid source containing Si atoms, is used as the hafnium source, the high vapor pressure of the hafnium source lowers the temperature of the source supply part to improve the stability of the equipment. The deposition rate can be improved by a short process time. In addition, excellent step coverage and thickness uniformity of the thin film can be improved.

Claims (9)

delete In the HfO ₂ film formation method using the atomic layer deposition method, Supplying a first reactant, which is a hafnium metal organic material containing Si atoms, to adsorb the hafnium metal organic material to a surface of the semiconductor substrate into a reactor loaded with a semiconductor substrate; Removing unreacted first reactant and reaction byproducts; Supplying an oxygen source, a second reactant, into the reactor to react with hafnium metal organics adsorbed on the surface of the semiconductor substrate; And Removing unreacted second reactant and reaction byproducts; To 1 cycle, wherein the cycle is repeated one or more times to form an HfO ₂ film. The method of claim 2, The hafnium metal organic material is Hf {N [Si (CH ₃ ) ₃ ] ₂ } ₄ , Hf {N [Si (C ₂ H5) ₃ ] ₂ } ₄ , Hf [NHSi (CH ₃ ) ₃ ] ₄ and Hf [NHSi (C ₂ H ₅ ) ₃ ] ₄ hafnium oxide film forming method using an atomic layer deposition method, characterized in that any one selected. The method of claim 2, The oxygen source is a hafnium oxide film forming method using an atomic layer deposition method, characterized in that any one selected from H ₂ O, H ₂ O ₂ , O ₂ and O ₃ . The method of claim 2, And the temperature of the semiconductor substrate is maintained at 100 to 600 ℃ during the cycle. The method of claim 2, And the pressure in the reactor is maintained at 10 Torr or less during the cycle. The method of claim 2, Removing the first reactant and the second reactant and the reaction by-product comprises a purge step using an inert gas. The method of claim 2, Removing the first and second reactants and reaction by-products comprises evacuating at a pressure lower than the pressure at the time of supplying the first and second reactants. The method of claim 2, Removing the first and second reactants and reaction by-products A purge step using an inert gas, And evacuating at a pressure lower than the pressure at the time of supplying the first reactant and the second reactant.

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