KR100209377B1 - Method for forming capacitor of semiconductor device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a capacitor of a semiconductor device, wherein a titanium (Ti) film / titanium nitride (TiN) film interposed between a semiconductor substrate and a diffusion barrier film of a Ru film in a capacitor using a ruthenium (Ru) film as a lower electrode. Oxidation is carried out by rapid thermal treatment of oxygen to form a titanium oxide film (TiNO) film, and a Ru film is formed as a lower electrode on the upper part to form a capacitor to prevent mutual diffusion between the Ru film and the titanium silicide (TiSi) film. A technique for improving the high temperature thermal stability of an electrode.

Description

Capacitor Manufacturing Method of Semiconductor Device

The present invention relates to a method for manufacturing a capacitor of a semiconductor device, and more particularly, to a surface of a TiN film formed of a diffusion barrier film in a storage electrode using a contact plug and an oxidizing metal at a high temperature and rapid heat treatment in an oxygen atmosphere, to the bottom of the TiSi film. _{The present} invention relates to a technique for improving the high temperature thermal stability of a storage electrode by forming an _x film and a TiNO film thereon.

In general, with the trend toward higher integration of semiconductor devices, the cell size is reduced, making it difficult to form capacitors with sufficient capacitance.

In particular, in a DRAM device having a unit cell composed of one MOS transistor and a capacitor, reducing the area while increasing the capacitance of a capacitor, which occupies a large area on a chip, is an important factor for high integration of the DRAM device.

Therefore, in order to increase the capacitance of the capacitor, a method of using a material having a high dielectric constant as the dielectric film, reducing the thickness of the dielectric film, or increasing the surface area of the capacitor is used.

However, these methods have their respective problems. That is, a dielectric material having a high dielectric constant, such as (Ba, Sr) TiO ₃ , is difficult to be applied to an actual device because reliability and thin film characteristics are not surely confirmed.

In addition, in the capacitor using the high dielectric film as described above, a refractory oxide film or a conductive oxide film such as Pt or RuO ₂ / Ru is used as the storage electrode.

Looking at the conventional technology having a capacitor using the high-k dielectric as described above are as follows.

Forming an insulating film having a storage electrode contact on the semiconductor substrate, forming a contact plug filling the contact hole with polycrystalline silicon, and then forming a diffusion barrier pattern contacting the polycrystalline silicon, a storage electrode made of a noble metal, A capacitor is formed by forming a dielectric film made of (Ba, Sr) TiO ₃ or the like and a plate electrode made of a noble metal.

However, in a highly integrated semiconductor device using a high dielectric film such as (Ba, Sr) TiO ₃ , when the lower electrode of RuO ₂ / Ru is used as the electrode of the high dielectric film, the solid state of the plug with the polycrystalline silicon by the manufacturing and heat treatment process of the capacitor As a result, high resistance Ru ₂ Si ₃ is formed, which adversely affects the contact resistance of the lower electrode.

Therefore, the introduction of the diffusion barrier film is inevitable, so the Ti / TiN film is used as a heat or stress preventing film between the plug polycrystalline silicon and the lower electrode in the lower structure of the high dielectric film, which is applied to TiN by physical vapor deposition which is commonly used. When the Ti film used for ohm contact is subjected to a high temperature heat treatment process, a titanium silicide film is formed, so that the diffusion prevention film due to coagulation is destroyed during the high temperature heat treatment process, and silicon and titanium diffuse through the TiN film, Reacting with the ruthenium (Ru) film used as an electrode, there is a problem that a high resistance RuSi film is formed to increase the contact resistance.

In addition, the TiN film maintains thermal stability up to about 700 ° C., but at a temperature higher than that, the TiN film forms a high-resistance thin film due to the aggregation of the titanium silicide film, thereby lowering the yield and reliability of the semiconductor device.

Accordingly, the present invention is to solve the above problems by oxidizing the surface of the TiN film formed as a diffusion barrier on the contact plug of the semiconductor substrate by rapid heat treatment in an oxygen atmosphere to form a TiN _x O _y film, and stored thereon By forming a Ru film as an electrode to form a capacitor, it is possible to prevent the mutual diffusion between the Ru film and the TiSi _x film to suppress the formation of a high resistance RuSi film, so that the yield and reliability of the semiconductor device capacitor can be improved. The purpose is to provide a manufacturing method.

1A to 1E are capacitor manufacturing process diagrams of a semiconductor device according to the present invention.

Figure 2a is a graph showing the atomic distribution according to the depth of the thin film by X-ray photoelectron spectroscopy measurement of the storage electrode not heat treated according to the present invention.

Figure 2b is a graph showing the atomic distribution according to the depth of the thin film by X-ray photoelectron spectroscopy measurement of the storage electrode heat-treated according to the present invention.

* Explanation of symbols for main parts of the drawings

10 semiconductor substrate 12 insulating film

13 contact hole 14 contact plug

16: titanium (Ti) film 18: titanium nitride (TiN) film

20: titanium oxynitride (TiN _x O _y ) film 22: titanium silicide (TiSi _x ) film

24: ruthenium (Ru) film 25: storage electrode

26 dielectric film 28 plate electrode

In order to achieve the above object, a method of manufacturing a capacitor of a semiconductor device according to the present invention includes forming an insulating film having a contact hole for a storage electrode on a semiconductor substrate, forming a contact plug filling the contact hole, and Forming a diffusion barrier film having a stacked structure of a Ti film / TiN film on the entire surface of the structure; and rapidly forming a TiN _x O _y film on the upper part by rapidly heat-treating the TiN film in an oxygen atmosphere, and a Ti film contacting the contact plug on the lower part. Reacting to form a TiSi _x film, forming a Ru film on the entire surface of the structure, etching until the Ti film is exposed, forming a storage electrode, and forming a dielectric film surrounding the storage electrode surface. And forming a plate electrode on the dielectric film.

Hereinafter, a method of manufacturing a capacitor of a semiconductor device according to the present invention will be described in detail with reference to the accompanying drawings.

1A to 1E are diagrams illustrating a capacitor manufacturing process of a semiconductor device according to the present invention.

First, a lower structure such as a device isolation insulating film (not shown), a gate oxide film (not shown), a gate electrode (not shown), and a bit line (not shown) are formed on the semiconductor substrate 10, and the insulating film 12 is formed on the entire surface of the semiconductor substrate 10. ).

Next, the insulating layer 12 is etched with a contact mask to form a contact hole 13 in a portion that is supposed to be a contact portion.

Next, a polycrystalline silicon film (not shown) is formed on the entire surface of the structure by chemical vapor deposition (CVD), and then the etching is performed so that the polycrystalline silicon film remains only inside the contact hole 13. A contact plug 14 filling the hole 13 is formed.

In this case, the polycrystalline silicon film is formed to a thickness of 500 ~ 3000Å.

Next, a diffusion barrier film formed of a laminated structure of the Ti film 16 / TiN film 18 is sequentially formed on the entire surface of the structure.

At this time, the Ti film 16 is formed to a thickness of 100 ~ 1000Å, the TiN film 18 is formed to a thickness of 200 ~ 2000Å (see Fig. 1a).

Subsequently, the TiN 18 was subjected to a high temperature rapid heat treatment in an oxygen atmosphere at a temperature of 500 ° C. to 800 ° C., a time of 10 seconds to 60 seconds, and an oxygen flow rate of 0.1 to 1 SLM in a TiN _x O _{y manner.} The film 20 is formed.

At this time, the diffusion of oxygen between the contact plug 14 by reacting a Ti film 16 to be in contact with silicon TiSi _x film 22 is formed, and the TiN film 18 and the TiSi _x film 22 of TiO film (not shown) may be formed in combination with (see also FIG. 1b).

Next, a Ru film 24 having a thickness of 500 to 5000 mm is formed on the entire surface of the structure.

Here, since the TiN _x O _y film 20 formed at the interface of the TiN film 18 and the TiSi _x film 22 is formed, mutual diffusion between the TiSi _x film 22 and the Ru film 24 is prevented. This makes it possible to suppress the formation of a high resistance thin film (see also 1c).

Next, the storage electrode etch mask is sequentially removed to the Ti film 16 by a photolithography process, and thus the Ru film 24 / TiN _x O _y film 20 / TiN film 18 contacting the contact plug 14. A storage electrode 25 formed in a stacked structure of the / TiSi _x film 22 pattern is formed (see also FIG. 1d).

Next, a dielectric film 26, such as BST, PZT, or the like, is formed to surround the storage electrode 25.

Next, according to the present invention, the plate electrode 28 is formed on the dielectric layer 26 by using a conductive oxide such as RuO ₂ or an oxide-resistant metal such as Pt on the dielectric layer 26 by CVD. A capacitor of the semiconductor element is formed (see also FIG. 1e).

On the other hand, Figure 2a according to the experimental results of the present invention is a graph showing the atomic distribution according to the depth of the thin film by X-ray photoelectron spectroscopy measurement of the storage electrode not heat treated in the present invention, Figure 2b is a heat treatment in the present invention A graph showing the atomic distribution according to the depth of the thin film by X-ray photoelectron spectroscopy measurement of the storage electrode is shown.

First, FIG. 2A shows atomic distribution according to the depth of a thin film in a laminated structure consisting of a conventional Ru film 24 / TiN film 18 / Ti film 16 / polycrystalline silicon film. It can be seen that the silicon is formed to a depth of about 20%.

Next, FIG. 2B shows the atomic distribution according to the depth of the thin film in the laminated structure consisting of the Ru film 24 / TiN film 18 / Ti film 16 / polycrystalline silicon film by rapid thermal treatment. 24) It can be seen that the depth of silicon is formed to about 0% on the surface.

Accordingly, the diffusion of the TiSi _x film 22 and the Ru film 24 can be prevented to suppress formation of a high resistance RuSi film.

As described above, the method of manufacturing a capacitor of a semiconductor device according to the present invention forms a TiN _x O _y film by performing a high temperature rapid heat treatment on the surface of a diffusion barrier TiN film interposed between a contact plug and a storage electrode to form a TiN _x O _y film in a subsequent process. By preventing diffusion with the film to improve high temperature thermal stability, there is an effect of improving the yield and reliability of the semiconductor device.

Claims (5)

Forming an insulating film having a contact hole for a storage electrode on the semiconductor substrate, forming a contact plug to fill the contact hole, and a diffusion barrier film having a Ti film / TiN film laminated on the entire surface of the structure. Forming a TiN _x O _y film at the upper part by rapid thermal treatment of the TiN film in an oxygen atmosphere, and forming a TiSi _x film by reacting the Ti film in contact with the contact plug at the lower part thereof, and forming Ru on the entire surface of the structure. And forming a storage electrode by etching until the Ti film is exposed, forming a dielectric film surrounding the surface of the storage electrode, and forming a plate electrode on the dielectric film. A method for manufacturing a capacitor of a semiconductor device. The method according to claim 1, wherein the oxidation process is carried out by a rapid heat treatment method, the temperature is 500 ℃ to 800 ℃, the time is 10 seconds to 60 seconds, the oxygen flow rate is carried out in the range of 0.1 ~ 1 SLM of the semiconductor device Capacitor Manufacturing Method. The method of manufacturing a capacitor of a semiconductor device according to claim 1, wherein the Ti film is formed to have a thickness of 100 mW to 1000 mW. The method of claim 1, wherein the TiN film has a thickness of about 200 μs to about 2000 μs. The method of claim 1, wherein the diffusion barrier is formed by CVD.

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