KR20080079514A - Method of manufacturing semiconductor device - Google Patents

Abstract

A method for manufacturing a semiconductor device is provided to improve the efficiency of a process by using a source containing Sr(C5(CH3)5)2 when forming a conductive oxide layer of a Perovskite structure. A substrate(10) is prepared. A first source containing Sr(C5(CH3)5)2, a second source containing Ru, and reactive gas are supplied to the substrate to form a conductive oxide layer(45) of a Perovskite structure on the substrate. The second source is one selected from Ru(tmhd)3, Ru(mhd)3, Ru(od)3, Ru(cp)2, Ru(Mecp)2, and Ru(Etcp)2. The conductive oxide layer is SrRuO3. The reactive gas is O3, O2, or H2O. The supplying of the first source, the second source, and the reactive gas is performed by an ALD(Atomic Layer Deposition) method. Alternatively, the supplying of the first source, the second source, and the reactive gas is performed by a CVD(Chemical Vapor Deposition) method.

Description

Manufacturing method of semiconductor device {METHOD OF MANUFACTURING SEMICONDUCTOR DEVICE}

1 is a flowchart showing a CVD method in the manufacture of a semiconductor device according to the present invention.

2 is a flowchart illustrating an ALD method in manufacturing a semiconductor device according to the present invention.

3 to 8 are cross-sectional views illustrating a method of manufacturing a semiconductor device according to the present invention.

<Description of the symbols for the main parts of the drawings>

10 semiconductor substrate 20 first interlayer insulating film

25 contact 30 second interlayer insulating film

33: opening 35: first conductive film

35a: storage node 40: sacrificial insulating film

40a: sacrificial pattern 45: dielectric film

50: second conductive film

The present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a method for manufacturing a semiconductor device including a conductive oxide film.

As various communication device and storage device technologies are developed, high speed and high capacity semiconductor devices are required. Therefore, in order to integrate semiconductor devices, design rules of semiconductor devices have been reduced.

Dynamic Random Access Memory (DRAM) requires a large capacity capacitor to store the signal do. In general, the capacitance C of the capacitor is

It is expressed as Where ε ₀ is the dielectric constant in vacuum, ε is the dielectric constant of the capacitor dielectric film, A is the effective area of the capacitor, and d is the thickness of the dielectric film. In the highly integrated semiconductor device, there is a limit in reducing the thickness of the dielectric film, so a method of increasing the capacitance of the capacitor may be to increase the effective area and the dielectric constant.

In general, a method of increasing the effective area of contact between the storage node and the dielectric layer has been studied. In particular, the method of increasing the height of the storage node of the capacitor has been studied a lot by the simplicity of the process. However, due to the reduction of design rules, continually increasing the height of the storage node having a narrow width causes the node to leak or the like. The tilting phenomenon may cause a malfunction of the semiconductor device, thereby lowering reliability.

A method of increasing the dielectric constant is to use a Perovskite oxide film containing SrTiO ₃ , BST [(Ba, Sr) TiO ₃ ], PZT, or SBT having high dielectric constant (High-k) as a dielectric film of a capacitor. will be. In this case, a conductive metal such as platinum (Pt), ruthenium (Ru), iridium (Ir), or TiN may be used as the lower electrode of the capacitor. However, when the metals are used as the lower electrode, the perovskite oxide film may not be good at the interface. Therefore, as the thickness of the perovskite oxide film becomes thinner, the characteristics may decrease at the interface between the lower electrode and the perovskite oxide film and the characteristics of the semiconductor device may decrease.

Recently, in order to solve the above problems, researches have been made on oxide films having a perovskite structure, such as a dielectric film, having excellent conductivity as a lower electrode. However, in order to form a thick electrode, unlike the dielectric film, the process time may be delayed. In general, since the oxide film is formed by a thermal process, when the process time is delayed, the stability of the thin film may be reduced. As a result, the characteristics of the semiconductor device may be degraded.

Accordingly, an object of the present invention for solving the above problems is to provide a method for manufacturing a semiconductor device that can improve process efficiency and improve the reliability of the semiconductor device.

A method of manufacturing a semiconductor device of the present invention for achieving the above object comprises the steps of providing a substrate and a first source containing Sr (C ₅ (CH ₃ ) ₅ ) ₂ on the substrate, a second source containing Ru And providing a reactive gas to form a conductive oxide film having a perovskite structure on the substrate.

According to an embodiment, the second source is one selected from Ru (tmhd) ₃ , Ru (mhd) ₃ , Ru (od) ₃ , Ru (cp) ₂ , Ru (Mecp) _2, and Ru (Etcp) ₂ . Can be.

According to another embodiment, the conductive oxide layer may be SrRuO ₃ .

According to another embodiment, the reaction gas may be O ₃ , O ₂ or H ₂ O.

According to another embodiment, the providing of the first and second sources and the reaction gas may be performed by ALD. At this time, the first source may be provided by a liquid delivery system (LDS). The liquid delivery system provides the first source by vaporizing in a liquid state, which may be maintained below 200 ° C. after vaporizing.

According to another embodiment, the step of providing the first and second sources and the reaction gas may be by CVD. At this time, the first source may be provided by a liquid delivery system (LDS). The liquid delivery system provides the first source by vaporizing in a liquid state, which may be maintained below 200 ° C. after vaporizing.

According to another embodiment, the substrate may be maintained below 400 ° C.

According to another embodiment, the method may further include forming a dielectric film on the conductive oxide film. The dielectric layer may have a perovskite structure. In this case, the dielectric layer may include Ti. The dielectric film may be formed by CVD or ALD.

According to another embodiment, the method may further include forming a conductive film on the dielectric film. The conductive layer may include a conductive oxide having a perovskite structure. The conductive layer may be SrRuO ₃ or (Ba, Sr) RuO ₃ .

In still another embodiment, the method may further include forming a mold pattern having grooves on the substrate, and the conductive oxide layer may be uniformly formed on the mold pattern. After forming the conductive oxide film having the perovskite structure, forming a buried film on the conductive oxide film, planarizing the buried film to remove the conductive oxide film on the mold pattern, and removing the buried film to form a storage node. Forming and removing the mold pattern may include.

According to another embodiment, a third source containing Ba may be further provided. The conductive oxide layer may be (Ba, Sr) RuO ₃ .

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the following examples and can be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosure may be made thorough and complete, and to fully convey the spirit of the present invention to those skilled in the art. In the drawings, the thicknesses of layers and regions are exaggerated for clarity. Parts denoted by the same reference numerals throughout the specification represent the same components.

Referring to FIG. 1, a method of forming a chemical vapor deposition (CVD) thin film of a semiconductor device of the present invention will be described. Referring to FIG. 1, a substrate is provided (S101). The substrate may be a semiconductor substrate, preferably a silicon substrate. Sources to be provided to the substrate are vaporized (S102).

The vaporized sources are provided to the reaction chamber in which the substrate is mounted (S103). The sources may be provided by pressurized carrier gas, such as an inert gas such as nitrogen, helium or argon. Vaporization and provision of the sources may be performed by a liquid delivery system (LDS). In addition, vaporization and provision of the sources can be performed using a conventional bubbler. Sources provided on the substrate include a first source comprising Sr and a second source comprising Ru. The first source may comprise Sr (C ₅ (CH ₃ ) ₅ ) ₂ , and the second source may be Ru (TMHD) ₃ , Ru (MHD) ₃ , Ru (OD) ₃ , Ru (CP) ₂ It may include Ru (MeCP) ₂ and Ru (EtCP) any of the materials of the _two. Since the first and second sources are in a solid state at room temperature, they may be provided dissolved in an organic solvent. For example, after dissolving the first source and / or the second source in an organic solvent, respectively, the first source and / or the second source is dissolved, thereby heating the first source and / or the second source. Can be. Thus, the vaporized first source and second source may be provided to the reaction chamber, for example, on which the substrate is placed. In this case, the first source Sr (C ₅ (CH ₃ ) ₅ ) ₂ may be provided to be vaporized at a temperature lower than about 200 ° C., which is relatively low in molecular weight compared to a source including Sr. Thus, not only the first source can be vaporized in a relatively fast time, but also provided to the substrate. The second sources, such as Ru (OD) ₃ and Ru (EtCP) ₂ , are similar in vapor pressure to Sr (C ₅ (CH ₃ ) ₅ ) ₂ , which is the first source, and thus, Sr (C ₅ (CH _{3). 5} ) As shown in FIG. ₂ , the vaporization rate and the supply rate to the substrate may be fast.

When the first source and the second source are provided to the substrate, a reaction gas for activating the first and second sources may be provided together (S104). The reaction gas may be, for example, O ₃ , O ₂ or H ₂ O. For example, the reaction gas may be provided using a plasma.

The first source and the second source is chemically adsorbed on the substrate (S105). In addition, the reaction gas may react on the substrate. The substrate is heated to allow reaction of the first and second sources to be performed on the substrate. For example, the substrate can be maintained at about 400 ° C or less.

A purge process is performed to remove the first source and the second source that remain without participating in the reaction (S106). For example, the purge process may be performed with an inert gas such as nitrogen or argon.

When the purge process is completed, a conductive oxide film having a perovskite structure is completed on the substrate (S107). For example, the conductive oxide film may include SrRuO ₃ having a perovskite structure.

At this time, in the above process, the conductive oxide film having a perovskite structure including (Ba, Sr) RuO ₃ may be formed by further providing a source including Ba as a third source. For example, the third source may include Ba (C ₅ (CH ₃ ) ₅ ) ₂ .

The thickness and speed of the conductive oxide film can be adjusted by controlling the energy, ratio and amount of sources provided for the reaction.

A method of forming an ALD (Atomic Layer Deposition) thin film of the semiconductor device of the present invention will be described with reference to FIG. 2. Referring to FIG. 2, a substrate is provided (S201). The substrate is maintained at about 400 ° C. or less to allow the provided sources to react on the substrate. Sources to be provided to the substrate are vaporized (S202). The sources may be dissolved in a solvent and vaporized.

A first source of the vaporized sources is first provided into the reaction chamber (S203). In this case, the first source may contain Sr. For example, the first source may include Sr (C ₅ (CH ₃ ) ₅ ) ₂ . The Sr (C ₅ (CH ₃ ) ₅ ) ₂ may have a molecular weight of about 200 ° C. or less until it is provided to the substrate. In addition, the substrate may be provided at a faster speed than conventional materials.

The first source is chemically absorbed (Chemical absorption) to the substrate (S204). The first gas remaining in the reaction chamber without chemisorption on the substrate is purged by an inert gas such as argon or nitrogen (S205).

Reaction gas is provided to the reaction chamber (S206). The reaction gas may be, for example, O ₃ , O ₂ or H ₂ O. For example, the reaction gas may be provided using a plasma. The first source adsorbed on the substrate by the reaction gas is oxidized to form an adsorption oxide film containing SrO (S207). The reaction gases remaining after the reaction may be purged by an inert gas and discharged from the reaction chamber.

A second source is provided to the reaction chamber (S208). The second source may comprise a _{Ru (TMHD) 3, Ru (} MHD) 3, Ru (OD) 3, Ru (CP) 2, Ru (MeCP) 2 and Ru (EtCP) any one material selected from the group consisting of ₂ .

The second source is adsorbed on the surface of the adsorption oxide film (S209). The second source remaining after adsorption reaction with the adsorption oxide film is purged (S210). The purge can be performed using an inert gas such as pressurized argon or nitrogen.

The reaction gas is provided to the reaction chamber (S211). As described above, the reaction gas may be O ₃ , O _2, or H ₂ O.

RuO ₂ is formed by oxidizing Ru of the second source by the reaction gas. Therefore, a conductive oxide film having a perovskite structure including SrRuO ₃ is further formed using SrO and RuO ₂ as one conductive oxide film (S212). Thereafter, the remaining reactive gas which does not participate in the reaction may be discharged from the reaction chamber by the inert gas.

The above process is called 1 cycle. That is, since one conductive oxide film is formed by one cycle, the thickness of the conductive oxide film can be adjusted by repeating the cycle. In the process, the supply order of the first source and the second source may be performed interchangeably. In the above process, a conductive oxide film having a perovskite structure including (Ba, Sr) RuO ₃ may be formed by additionally performing a series of processes of vaporizing and providing a third source, and adsorption reaction and oxidation. . For example, the third source may include Ba (C ₅ (CH ₃ ) ₅ ) ₂ .

Hereinafter, a method of forming a semiconductor element of the present invention will be described.

Previously, an oxide film containing Ti may be formed on the conductive oxide film formed by CVD or ALD. For example, the oxide film containing Ti (hereinafter, referred to as a "Ti oxide film") may be SrTiO 3 or (Ba, Sr) TiO 3. The Ti oxide film may be formed in the same manner as described above by CVD or ALD. Since the Ti oxide film has a perovskite structure having the same structure as the conductive oxide film, the Ti oxide film may have excellent interface characteristics. In addition, since the Ti oxide film has a high dielectric constant, the Ti oxide film can function as a dielectric film.

By using the conductive oxide film as the upper and lower electrodes and the Ti oxide film as the dielectric film, a capacitor of the semiconductor device may be formed.

3 to 8, a method of manufacturing a semiconductor device of the present invention will be described. Referring to FIG. 3, a semiconductor substrate 10 is provided. An active region (not shown) may be defined in the semiconductor substrate 10 by an isolation region (not shown). In addition, a conductive pattern (not shown) such as a gate may be formed on the semiconductor substrate 10. On the semiconductor substrate 10, a first interlayer insulating film 20 is formed. By using a conventional method, a portion of the first interlayer insulating film 20 may be etched and filled with a conductive material to be connected to a conductive region (active region and / or conductive pattern) on the semiconductor substrate 10. Is formed. For example, the contact 25 may be formed of multiple layers of a polysilicon layer and a silicide layer in order to reduce contact resistance. In addition, a diffusion barrier layer (not shown) may be formed to prevent oxygen diffusion. It may also be planarized by an etch back or conventional chemical mechanical polishing (CMP) process.

Referring to FIG. 4, a second interlayer insulating layer 30 is formed on the first interlayer insulating layer 20 including the contact 25. An opening 33 is formed to expose the contact 25 by etching a portion of the second interlayer insulating layer 30 using a conventional photolithography process.

Referring to FIG. 5, a first conductive layer 35 is formed along the profile of the second interlayer insulating layer 30 and the opening 33. For example, the first conductive layer 35 may include SrRuO ₃ or (Ba, Sr) RuO ₃ as the conductive oxide having the perovskite structure described above. The first conductive layer 35 may be formed by ALD or CVD. The first conductive layer 35 may have a desired thickness by adjusting the conditions of the CVD method or the ALD method.

Referring to FIG. 6, a sacrificial insulating layer 40 is formed on the first conductive layer 35. Since the sacrificial insulating layer 40 must fill the opening, it is preferable to use a material having excellent gap filling properties. For example, the sacrificial insulating layer 40 may include Boron Phosphorus Silicate Glass (BPSG), Spin On Glass (SOG), or Phosphorus Silicate Glass (PSG).

Referring to FIG. 7, the sacrificial insulating layer 40 is planarized to remove the first conductive layer 35 on the second interlayer insulating layer 30. The planarization can be performed by conventional etch back or chemical mechanical polishing processes. Accordingly, the cylindrical storage node 35a is formed in the opening, and the sacrificial pattern 40a remains. The shape of the storage node 35a is not limited to the shape of a cylinder and may vary.

Referring to FIG. 8, the storage node 35a is exposed by removing the second interlayer insulating layer 30 and the sacrificial pattern 40a. The second interlayer insulating layer 30 and the sacrificial pattern 40a may be removed at the same time or sequentially. In this case, the second interlayer insulating layer 30 and the sacrificial pattern 40a may be etched with a selectivity higher than that of the storage node 35a so that the storage node 35a is not damaged during the etching process. A dielectric layer 45 is formed on the storage node 35a. The dielectric layer 45 may be a conductive oxide layer having a perovskite structure including SrTiO ₃ having high dielectric constant, BST [(Ba, Sr) TiO ₃ ], PZT, or SBT. Therefore, since the dielectric layer 45 has the same perovskite structure on the storage node 35a, an interface property between the storage node 35a and the dielectric layer 45 may be improved. Thus, even if the thickness of the dielectric film 45 is thin, the dielectric film 45 may perform its function in the semiconductor device. For example, the dielectric layer 45 may be formed by ALD or CVD. Gases containing Sr (eg, Sr (C ₅ (CH ₃ ) ₅ ) ₂ ) and Ti as source gas may be used. The second conductive layer 50 is formed on the dielectric layer 45. The second conductive layer 50 may include a conventional conductive material or may include the same material as the storage node 35a. Therefore, an interface property between the dielectric layer 45 and the second conductive layer 50 may be improved.

In the above, the capacitor of the semiconductor device may be completed using the second conductive layer 50 as the upper electrode.

According to the method for manufacturing a semiconductor device of the present invention, a source containing Sr (C ₅ (CH ₃ ) ₅ ) ₂ is used to form a conductive oxide film having a perovskite structure containing Sr and / or Ru. . Since the source has a small molecular weight, the source may be easily vaporized and the deposition rate may be improved, thereby improving process efficiency. In addition, the degree of contamination in the device can be reduced. In addition, when a dielectric film having a high dielectric constant having another perovskite structure is formed on the conductive oxide film, the interfacial property is excellent and the step coverage is excellent, so that the reliability of the semiconductor device can be improved.

Claims (20)

Providing a substrate; And Providing a first source containing Sr (C ₅ (CH ₃ ) ₅ ) ₂ , a second source containing Ru, and a reactant gas on the substrate to form a conductive oxide film having a perovskite structure on the substrate. Method for manufacturing a semiconductor device comprising the step. The method of claim 1, The second source is a semiconductor, characterized in that one selected from Ru (tmhd) ₃ , Ru (mhd) ₃ , Ru (od) ₃ , Ru (cp) ₂ , Ru (Mecp) ₂ and Ru (Etcp) ₂ Method of manufacturing the device. The method of claim 1, The conductive oxide film is a method of manufacturing a semiconductor device, characterized in that SrRuO ₃ . The method of claim 1, The reaction gas is a manufacturing method of a semiconductor device, characterized in that O ₃ , O ₂ or H ₂ O. The method of claim 4, wherein Providing the first and second sources and the reactant gas includes: A method of manufacturing a semiconductor device, characterized by the ALD method. The method of claim 4, wherein Providing the first and second sources and the reactant gas includes: A method for manufacturing a semiconductor device, characterized by a CVD method. The method of claim 5 or 6, And wherein said first source is provided by a liquid delivery system (LDS). The method of claim 7, wherein And wherein said liquid delivery system vaporizes said first source in a liquid state, said first source being held at 200 ° C. or less after vaporizing. The method of claim 8, The substrate is a method of manufacturing a semiconductor device, characterized in that maintained at 400 ℃ or less. The method of claim 9, Forming a dielectric film on the conductive oxide film further comprising the step of manufacturing a semiconductor device. The method of claim 10, The dielectric film has a perovskite structure, characterized in that the manufacturing method of the semiconductor device. The method of claim 11, And the dielectric film comprises Ti. The method of claim 12, The dielectric film is a method of manufacturing a semiconductor device, characterized in that formed by CVD or ALD method. The method of claim 13, And forming a conductive film on the dielectric film. The method of claim 14, The conductive film is a method of manufacturing a semiconductor device, characterized in that it comprises a conductive oxide having a perovskite structure. The method of claim 15, The conductive film is a method of manufacturing a semiconductor device, characterized in that SrRuO ₃ or (Ba, Sr) RuO ₃ . The method of claim 1, And forming a mold pattern having grooves on the substrate, wherein the conductive oxide film is uniformly formed on the mold pattern. The method of claim 17, After forming the conductive oxide film having the perovskite structure, forming a buried film on the conductive oxide film; Planarizing the buried film to remove the conductive oxide film on the mold pattern; Removing the buried film to form a storage node; And Removing the mold pattern. The method of claim 1, A method for manufacturing a semiconductor device, further comprising a third source containing Ba. The method of claim 19, The conductive oxide film is a manufacturing method of a semiconductor device, characterized in that (Ba, Sr) RuO ₃ .

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