JP2001085640A - Semiconductor device and fabrication method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a stacked capacitor in which deterioration of characteristics due to oxidation of an adhesion layer (or barrier layer) is prevented by employing a structure where the adhesion layer (or barrier layer) is spaced apart from a dielectric film. SOLUTION: The semiconductor device comprises a tubular bottomed first electrode 21, a dielectric film 22 formed at least on the inner surface of the first electrode 21, and a second electrode 23 formed at least on the inside of the first electrode 21 through the dielectric film 22 wherein an adhesion layer 15 is provided at least on the bottom of the first electrode 21. The adhesion layer 15 is isolated from the dielectric film 22 by means of an insulation film 16, a sidewall 17 or the first electrode 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a method of manufacturing the same, and more particularly, to a semiconductor device having a metal-insulating film-metal capacitor having a small leakage current and a method of manufacturing the same.

[0002]

2. Description of the Related Art A DRAM (Dynamic Random Access Memory) has a memory cell structure having a switching MOSFET and a memory capacitor. In recent years, this DRAM has been increasingly miniaturized, and its capacity and integration have been promoted. For example, a DRAM having a storage capacity of several Gbits has been announced at the academic level as a process driver in a semiconductor device. . With the miniaturization, the size of memory cells has been reduced, and the area occupied by memory capacitors has also been reduced. And D
The most important thing for a memory capacitor such as a RAM is to secure a required amount of storage capacity of the memory capacitor in order to increase the reliability of stored data.

In general, the storage capacitance value needs to be about 20 pF to 40 pF regardless of the device generation. This value is because the number of cells connected to the bit line tends to increase to reduce the chip area and to increase the total capacity and the total leakage current of the bit line in order to secure the soft error resistance due to the α-ray. Since Vth cannot be reduced from the viewpoint of the leakage current of the cell transistor, the voltage is reduced, and the accumulated signal voltage is reduced accordingly. This is determined in order to ensure reading of a small signal. Therefore, as the memory capacitor is miniaturized, it is necessary to secure a required amount of storage capacity, despite the occupation area thereof being reduced, and various measures have been taken for that purpose.

[0004] Further, as a demand for application to a logic device embedded with a DRAM, there is a demand for a manufacturing temperature of a capacitor from the viewpoint of consistency with a process having a low heat resistance claim such as a salicide technique or a dual gate technique used for a logic device. There is also a strong demand for lower temperatures.

[0005] From the above background, attempts have been made to achieve the requirements by improving the capacitor electrode material and the constituent material of the insulating film based on the MIM structure. For example, tantalum oxide (Ta)
High dielectric film or BST like ₂ O ₅₎ (SrBi ₂
A technique using a ferroelectric film such as a metal oxide such as Ta ₂ O ₉ : bismuth strontium tantalum oxide) and STO (Sr ₂ Ta ₂ O ₇ : strontium tantalum oxide) has also been developed. When a metal electrode material is contacted with a metal oxide and subjected to a heat treatment, the material is oxidized to become an insulating film having deteriorated characteristics. Therefore, a material having high oxidation resistance [for example, tungsten nitride (W ₂ N), platinum (Pt)] Etc.) or a material exhibiting conductivity even when oxidized [ruthenium (R
u), iridium (Ir)] and the like have been proposed for electrodes.

Next, a first prior art relating to a method of manufacturing a capacitor having an MIM structure will be described with reference to a manufacturing process diagram of FIG. 7, and a second conventional technology will be described with reference to a manufacturing process diagram of FIG. .

First, a first conventional technique will be described. FIG.
As shown in (1), the interlayer insulating film 1 is formed on the substrate 111.
12 are formed, and a connection hole 113 serving as a storage node contact is formed in the interlayer insulating film 112. Thereafter, a polysilicon plug 114 is formed inside the connection hole 113 by a known polysilicon embedding technique.

Next, as shown in FIG. 7B, an adhesion layer 115 covering the polysilicon plug 114 is formed on the interlayer insulating film 112 in a laminated structure of a titanium film and a titanium nitride film. Further, the lower electrode material layer 116 is formed of tungsten or tungsten nitride. Then, as shown in (3) of FIG. 7, the lower electrode material layer 116 and the adhesion layer 115 are patterned by using a normal lithography technique and an etching technique, and the polysilicon plug 114 is formed through the adhesion layer 115. A lower electrode 117 to be connected is formed.

Thereafter, as shown in FIG. 7D, a capacitor dielectric film 118 covering the lower electrode 117 is formed of tantalum oxide. Further, the capacitor dielectric film 118
The upper electrode 119 is formed thereon with tungsten, tungsten nitride, or titanium nitride.

Next, a second conventional technique will be described. FIG.
As shown in (1), the interlayer insulating film 1 is formed on the substrate 111.
12 are formed, and a connection hole 113 serving as a storage node contact is formed in the interlayer insulating film 112. Thereafter, a polysilicon plug 114 is formed inside the connection hole 113 by a known polysilicon embedding technique.

Next, a stopper layer 121 covering the polysilicon plug 114 is formed on the interlayer insulating film 112 by using silicon nitride. Further, a core oxide film 122 is formed on the stopper layer 121. Then, the core oxide film 122 and the stopper layer 121 are patterned using a normal lithography technique and an etching technique to form a hole 12 for forming a capacitor reaching the polysilicon plug 114.
Form 3

Next, as shown in FIG. 8B, an adhesion layer 124 is formed on the inner surface of the hole 123 and the core oxide film 122.
Is formed in a laminated structure of a titanium film and a titanium nitride film. Further, the lower electrode material layer 125 is formed of tungsten.
The adhesion layer 124 also has a function as a barrier layer for preventing a reaction between the polysilicon plug 114 and an upper electrode formed later.

Then, the lower electrode material layer 125 and the adhesion layer 124 on the core oxide film 122 are removed, and the core oxide film 122 is removed. As a result, as shown in FIG. 8C, the lower electrode 12 made of a bottomed cylindrical lower electrode material 125 whose bottom and outside are wrapped by the adhesion layer 124.
6 was formed.

Thereafter, as shown in FIG. 8D, a dielectric film 127 covering the lower electrode 126 is formed of tantalum oxide. Further, an upper electrode 128 is formed on the dielectric film 127 using tungsten, tungsten nitride, or titanium nitride.

As described above, when a metal film such as tungsten is used as the lower electrode material, it is necessary to form an adhesion layer in advance to prevent film peeling. In addition, a polysilicon plug is used for a DRAM cell, particularly a storage node, in order to maintain a low junction leak. In this case, a polysilicon plug 11 is used as a film for preventing reaction with the electrode material.
4 requires a so-called barrier layer. For the above reasons, when tungsten is used for the electrode material, a film to be a barrier layer and a film to be an adhesion layer such as a stacked film of titanium and titanium nitride or a single layer film of titanium nitride are required. .

[0016]

However, according to the general method of manufacturing a stacked capacitor, the above-described adhesion layer (barrier layer) is exposed on the side wall portion of the storage node electrode, so that the dielectric film and the barrier layer are not exposed. You will be in direct contact.
Because the dielectric film is formed of a high dielectric material made of a metal oxide, the oxygen in the film, or
The heat treatment in an oxidizing atmosphere performed to improve the characteristics of the dielectric film oxidizes the adhesion layer (barrier layer), causing an increase in leakage current in the oxidized portion, and the electrical characteristics. Deterioration occurs.

[0017]

SUMMARY OF THE INVENTION The present invention is directed to a semiconductor device and a method of manufacturing the same to solve the above-mentioned problems.

The semiconductor device comprises a first cylindrical electrode having a bottom, a dielectric film formed on at least an inner surface of the first electrode, and at least a first electrode formed on the first electrode through the dielectric film. And a second electrode formed inside,
An adhesive layer is provided at least on the bottom of the first electrode, and the adhesive layer and the dielectric film are formed in a separated state.

Specifically, the adhesion layer is formed on the bottom of the first electrode, the dielectric film is formed on the inner surface of and above the first electrode, and the second electrode is formed on the dielectric. The first electrode is formed inside and above the first electrode via a body film.

Alternatively, the adhesion layer is formed on the bottom of the first electrode, the dielectric film is continuously formed on the inner surface and the outer surface of the first electrode, and the second electrode is formed on the inner surface of the first electrode. The first electrode is formed continuously on the inner surface and the outer surface of the first electrode via a dielectric film.

Alternatively, the adhesion layer is formed continuously on the bottom of the first electrode and the outer surface thereof, and the dielectric film is formed on the inner surface of the first electrode and the upper thereof,
The second electrode is formed inside and above the first electrode via the dielectric film.

In the above-described semiconductor device, since the adhesion layer and the dielectric film are formed apart from each other, even if the dielectric film is formed of a high dielectric material made of metal oxide, the dielectric Since the adhesive layer portion is not oxidized by oxygen contained in the body film, an increase in leak current in the adhesive layer portion due to oxidation of the adhesive layer does not occur, and electrical characteristics do not deteriorate.

A first method of manufacturing a semiconductor device includes a step of forming a columnar first electrode pattern on a substrate via an adhesion layer, and a step of forming the first electrode pattern on the substrate between the first electrode patterns. Embedding an insulating film in a state higher than the electrode pattern, forming a sidewall made of an insulating film around the upper side of the first electrode pattern, and using the sidewall as a mask to form the first electrode pattern Is etched to form a cylindrical first electrode having a bottom with the first electrode pattern.
And forming a dielectric film on at least the inner surface of the first electrode, and forming a second electrode covering the dielectric film.

In the first method of manufacturing a semiconductor device, at the stage when the dielectric film is formed, the adhesion layer and the dielectric film are separated from each other by the insulating film, the sidewall, and the first electrode. Therefore, the adhesion layer is not oxidized by oxygen contained in the dielectric film. Further, since the adhesion layer is covered with an insulating film or the like, even if heat treatment is performed in an oxidizing atmosphere for improving the characteristics of the dielectric film, the adhesion layer does not come into contact with the oxidizing atmosphere. So it is not oxidized.

In a second method for manufacturing a semiconductor device, a step of forming a columnar first electrode pattern on a substrate via an adhesion layer and a step of forming the first electrode pattern on the substrate by the first electrode pattern are performed. Embedding an insulating film in a state higher than the electrode pattern, forming a sidewall made of an insulating film around the upper side of the first electrode pattern, and using the sidewall as a mask to form the first electrode pattern Is etched to form a cylindrical first electrode having a bottom with the first electrode pattern.
Forming an electrode, removing the insulating film while maintaining a state in which the insulating film covers the side surface of the adhesion layer, and forming a dielectric film on the inner surface and the outer surface of the first electrode. A manufacturing method comprising: a forming step; and a step of forming a second electrode on the inside and outside of the first electrode via the dielectric film.

In the second method of manufacturing a semiconductor device, at the stage when the dielectric film is formed, the adhesive layer and the dielectric film are separated from each other by the insulating film and the first electrode. The layer is not oxidized by the oxygen contained in the dielectric film. Further, since the adhesion layer is covered with an insulating film or the like, even if heat treatment is performed in an oxidizing atmosphere for improving the characteristics of the dielectric film, the adhesion layer does not come into contact with the oxidizing atmosphere. So it is not oxidized.

A third method of manufacturing a semiconductor device comprises the steps of: forming an insulating film on a substrate, forming a concave portion in the insulating film; forming an adhesive layer on the inner surface of the concave portion; Forming a first electrode film through the step, burying a mask insulating film inside the concave portion, and removing the first electrode film and the adhesion layer to a lower level than the insulating film; Forming a first electrode made of a first electrode film on the inner surface of the concave portion via the adhesion layer, forming a cap insulating film covering the first electrode and the adhesion layer, A step of selectively removing a mask insulating film; a step of forming a dielectric film on at least an inner surface of the first electrode; and a second electrode at least inside the first electrode via the dielectric film. And a step of forming.

In the third method of manufacturing a semiconductor device, at the stage when the dielectric film is formed, the adhesion layer and the dielectric film are separated from each other by the insulating film, the cap insulating film, and the first electrode. And is not oxidized by oxygen contained in the dielectric film. Further, since the adhesion layer is covered with an insulating film or the like, even if heat treatment is performed in an oxidizing atmosphere for improving the characteristics of the dielectric film, the adhesion layer does not come into contact with the oxidizing atmosphere. So it is not oxidized.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment According to a Semiconductor Device of the Present Invention
Will be described with reference to the schematic cross-sectional view of FIG.

As shown in FIG. 1, an interlayer insulating film 12 is formed on a substrate 11, and a connection hole 13 serving as a storage node contact is formed in the interlayer insulating film 12. Further, a polysilicon plug 14 is formed inside the connection hole 13.

On the polysilicon plug 14, an adhesive layer 15 connected to the polysilicon plug 15 is formed in a laminated structure of, for example, a titanium film and a titanium nitride film. On the adhesion layer 15, a cylindrical first electrode 21 having a bottom is formed of, for example, tungsten or tungsten nitride. The insulating film 16 is formed around the first electrode 21 and the adhesion layer 15 so as to be higher than the first electrode 21. Further, on the upper portion of the side wall of the insulating film 16, the side wall 1 covering the first electrode 21 is formed.
7 is made of a material that can have an etching selectivity with the insulating film 16 such as a silicon nitride film.

On at least the inner surface of the first electrode 21, a dielectric film 22 is formed of a high dielectric material such as tantalum oxide, BST (SrBi ₂ Ta ₂ O ₉ : bismuth strontium tantalum oxide), STO (Sr ₂ Ta
_It is made of a ferroelectric material such as a metal oxide such as ₂ O ₇ (strontium tantalum oxide). Specifically, the dielectric film 22 is formed on the inner surface of the first electrode 21, on the sidewall 17, and on the insulating film 16. Further, a second electrode 23 is formed at least inside the first electrode 21 with the dielectric film 22 interposed therebetween, for example, made of tungsten, tungsten nitride or titanium nitride. Specifically, the second electrode 23 embeds the inside of the first electrode 21, and
Is formed on.

When a ferroelectric material is used for the dielectric film 22, the first and second electrodes 21 and 23 are formed of platinum, an iridium alloy, or the like.

In the first semiconductor device, the dielectric film 22
And the adhesion layer 15, the insulating film 16, the side wall 17,
The first electrodes 21 are formed so as to be separated from each other. Therefore, even if the dielectric film 22 is formed of a high-dielectric material made of a metal oxide, the adhesive layer 15 is not oxidized by oxygen contained in the dielectric film 22. The leakage current in the portion of the adhesion layer 15 due to the oxidation of 15 does not increase, and the electrical characteristics do not deteriorate.

Next, a second embodiment of the semiconductor device according to the present invention will be described with reference to the schematic sectional view of FIG. 2, the same components as those shown in FIG. 1 are denoted by the same reference numerals.

As shown in FIG. 2, an interlayer insulating film 12 is formed on a substrate 11, and a connection hole 13 serving as a storage node contact is formed in the interlayer insulating film 12. Further, a polysilicon plug 14 is formed inside the connection hole 13.

On the polysilicon plug 14, an adhesive layer 15 connected to the polysilicon plug 15 is formed in a laminated structure of, for example, a titanium film and a titanium nitride film. On the adhesion layer 15, a cylindrical first electrode 21 having a bottom is formed of, for example, tungsten or tungsten nitride. Further, an insulating film 16 is formed of, for example, a silicon oxide film on the lower side of the first electrode 21 and around the adhesion layer 15. As illustrated, the stopper layer 31 may be formed on the lower surface of the insulating film 16 by, for example, a silicon nitride film.

The dielectric film 22 is made of a high dielectric material such as tantalum oxide or BST (SrBi ₂ Ta ₂ O) in a state where the dielectric film 22 is continuous with the inner and outer surfaces of the first electrode 21.
₉ : bismuth strontium tantalum oxide), STO
(Sr ₂ Ta ₂ O ₇ : strontium tantalum oxide)
It is formed of a ferroelectric material such as a metal oxide. Further, a second electrode 23 is formed at least inside the first electrode 21 with the dielectric film 22 interposed therebetween, for example, made of tungsten, tungsten nitride or titanium nitride. Specifically, the second electrode 23 is formed continuously inside and outside the first electrode 21 via the dielectric film 22.

When a ferroelectric material is used for the dielectric film 22, the first and second electrodes 21 and 23 are formed of platinum, an iridium alloy, or the like.

In the second semiconductor device, the dielectric film 22
The contact layer 15 is formed so as to be separated by the insulating film 16 and the first electrode 21. Therefore, even if the dielectric film 22 is formed of a high-dielectric material made of a metal oxide, the adhesive layer 15 is not oxidized by oxygen contained in the dielectric film 22. 1
No increase in the leak current occurs in the portion of the adhesion layer 15 due to oxidation of 5, and the electrical characteristics do not deteriorate.

Next, a third embodiment of the semiconductor device according to the present invention will be described with reference to the schematic sectional view of FIG. 3, the same components as those shown in FIG. 1 are denoted by the same reference numerals.

As shown in FIG. 3, an interlayer insulating film 12 is formed on a substrate 11, and a connection hole 13 serving as a storage node contact is formed in the interlayer insulating film 12. Further, a polysilicon plug 14 is formed inside the connection hole 13.

On the polysilicon plug 14, an adhesive layer 15 connected to the polysilicon plug 15 is provided.
The cylindrical first electrode 21 having a bottom is formed of, for example, tungsten or tungsten nitride. The adhesion layer 15 is continuously formed on the bottom and the outside of the first electrode, and has a laminated structure of, for example, a titanium film and a titanium nitride film. Further, on the outside of the adhesion layer 15,
The insulating film 1 is set higher than the first electrode 21 and the adhesion layer 15.
6 is formed of, for example, a silicon oxide film. Also,
The cap insulating film 18 is formed on the first electrode 21 and the adhesion layer 15.
Is formed of, for example, a silicon nitride film.

On the inner surface of the first electrode 21 and on the cap insulating film 18 and the insulating film 16, a dielectric film 22 is continuously formed of a high dielectric material such as tantalum oxide or BST (SrBi ₂ Ta ₂ O ₉ : bismuth strontium tantalum oxide), STO (Sr ₂ Ta ₂
It is formed of a ferroelectric material such as a metal oxide such as O ₇ (strontium tantalum oxide). Further, the inside of the first electrode 21 is buried through the dielectric film 22 and a second electrode 23 is continuously formed on the dielectric film 22 with, for example, tungsten, tungsten nitride or titanium nitride.

When a ferroelectric material is used for the dielectric film 22, the first and second electrodes 21 and 23 are formed of platinum, an iridium alloy, or the like.

In the third semiconductor device, the dielectric film 22
The contact layer 15 is formed so as to be separated from the insulating film 16, the cap insulating film 18, and the first electrode 21. Therefore, even if the dielectric film 22 is formed of a high dielectric material made of a metal oxide,
Is not oxidized by the oxygen contained in the adhesive layer 15, so that the oxidation of the adhesive layer 15 does not increase the leakage current in the portion of the adhesive layer 15, and the electrical characteristics do not deteriorate.

Next, an embodiment according to a first manufacturing method of the present invention will be described with reference to a manufacturing process sectional view of FIG.
FIG. 4 shows a method of manufacturing the semiconductor device described with reference to FIG. 1, and the same components as those shown in FIG.

As shown in FIG. 4A, an interlayer insulating film 12 is formed on a substrate 11, and a connection hole 13 serving as a storage node contact is formed in the interlayer insulating film 12. afterwards,
A polysilicon plug 14 is formed inside the connection hole 13 by a known polysilicon embedding technique. That is, after a polysilicon film is formed in a state in which the connection hole 13 is buried, the polysilicon film other than the inside of the connection hole 13 is removed by etch back or chemical mechanical polishing.
Then, a polysilicon plug 14 made of a polysilicon film is formed inside the semiconductor device 3.

Next, an adhesion layer 15 covering the polysilicon plug 14 is deposited on the interlayer insulating film 12 by, for example, sputtering to deposit a titanium film to a thickness of 30 nm and further depositing a titanium nitride film to a thickness of 50 nm. Form.
Then, RTA (Rapid Thermal Anion) at 700 ° C. for 30 minutes.
nealing) A densification process is performed. Thereafter, the first electrode film 24 is formed by depositing tungsten or tungsten nitride to a desired thickness by, for example, sputtering. The thickness of the first electrode film 24 is
The height of the electrode (lower electrode) is substantially determined, and is appropriately determined depending on the application generation of the device and the dielectric material used.

Next, the first electrode film 24 and the adhesion layer 15 are patterned using ordinary lithography and etching techniques and connected to the polysilicon plug 14 via the adhesion layer 15 to form a storage node pattern. A first electrode pattern 25 is formed.

Next, the insulating film 16 is formed to cover the first electrode pattern 25 by, for example, SOG (Spin on glass).
) It is formed by coating or high-density plasma CVD. Thereafter, the insulating film 16 is removed by a polishing technique (for example, chemical mechanical polishing) or an etch back until the upper portion of the first electrode pattern 25 is exposed. Further, the first electrode pattern 25 is etched by, for example, etching so as to be lower than the surface of the insulating film 16. As a result, the side of the first electrode pattern 25 is in a state where the insulating film 16 is buried in a state higher than the first electrode pattern 25.

Next, as shown in (2) of FIG.
On the electrode pattern 25 and the insulating film 16, an insulating film for a sidewall is formed of, for example, a silicon nitride film having etching selectivity with the insulating film 16. After that, the sidewall insulating film is etched back to form a sidewall 17 made of a silicon nitride film around the upper side of the first electrode pattern 25. The thickness of the side wall 17 determines the thickness of the first electrode (lower electrode) of the capacitor.

Next, as shown in FIG. 4C, the first electrode pattern 25 is etched using the insulating film 16 and the side walls 17 as an etching mask.
A cylindrical first electrode (lower electrode) 21 having a bottom is formed. In this etching, the etching is adjusted such that the bottom of the first electrode pattern 25 is left.

Next, as shown in FIG. 4 (4), a dielectric film 22 is formed on the inner surface of the first electrode 21, the side wall 17 and the insulating film 16 by, for example, a chemical vapor deposition method.
For example, it is formed by depositing tantalum oxide (Ta ₂ O ₅ ) to a thickness of 9 nm. Thereafter, heat treatment is performed in an ozone or oxygen atmosphere at a temperature of about 400 ° C. to 450 ° C. Alternatively, heat treatment is performed in an ozone atmosphere under irradiation of ultraviolet rays. Thereafter, tungsten or tungsten nitride is deposited so as to cover the dielectric film 22 by chemical vapor deposition to form a second electrode 23 serving as a cell plate electrode.

In the first method of manufacturing a semiconductor device, when the dielectric film 22 is formed, the adhesion layer 15 and the dielectric film 2 are formed.
2 is separated by the insulating film 16, the side wall 17 and the first electrode 21, and the adhesion layer 15 is not oxidized by oxygen contained in the dielectric film 22. Further, since the adhesion layer 15 is covered with the insulating film 16 and the like, even if the heat treatment in an oxidizing atmosphere for improving the characteristics of the dielectric film 22 is performed, the adhesion layer 1
5 is not oxidized because it does not touch the oxidizing atmosphere.

Next, an embodiment according to the second manufacturing method of the present invention will be described with reference to a manufacturing step sectional view of FIG.
FIG. 5 shows a method of manufacturing the semiconductor device described with reference to FIG. 2, and the same components as those shown in FIG. 2 are denoted by the same reference numerals.

The first electrode 22 is formed by the same manufacturing method as described with reference to FIG. 4 (1) to (3). Then, the side wall 17 and the insulating film 16 are
For example, it is removed by etching with hydrofluoric acid or the like. At this time, as shown in FIG. 5A, the insulating film 16 is left with such a thickness that the adhesion layer 15 is not exposed. Thus, the cylindrical first electrode 21 having a bottom is formed on the adhesion layer 15.

Next, as shown in FIG. 5 (2), for example, tantalum oxide (Ta ₂ O _{5) is} formed on the insulating film 16 from the inner surface to the outer surface of the first electrode 21 by, for example, chemical vapor deposition. ) Is deposited to a thickness of 9 nm to form a dielectric film 22.
To form Thereafter, heat treatment is performed in an ozone or oxygen atmosphere at a temperature of about 400 ° C. to 450 ° C. Alternatively, heat treatment is performed in an ozone atmosphere under irradiation of ultraviolet rays. Thereafter, tungsten or tungsten nitride is deposited so as to cover the dielectric film 22 by chemical vapor deposition to form a second electrode 23 serving as a cell plate electrode.

In the second method of manufacturing a semiconductor device, when the dielectric film 22 is formed, the adhesion layer 15 and the dielectric film 2 are formed.
2 is separated by the insulating film 16 and the first electrode 21, and is not oxidized by oxygen contained in the dielectric film 22. Further, since the adhesion layer 15 is covered with an insulating film or the like, for example, the dielectric film 2
Even if the heat treatment is performed in an oxidizing atmosphere for improving the characteristics of No. 2, the adhesion layer 15 is not oxidized because it does not contact the oxidizing atmosphere.

Next, an embodiment according to a third manufacturing method of the present invention will be described with reference to a manufacturing process sectional view of FIG.
FIG. 6 shows a method of manufacturing the semiconductor device described with reference to FIG. 3, and the same components as those shown in FIG.

As shown in FIG. 6A, an interlayer insulating film 12 is formed on a substrate 11, and a connection hole 13 serving as a storage node contact is formed in the interlayer insulating film 12. afterwards,
A polysilicon plug 14 is formed inside the connection hole 13 by a known polysilicon embedding technique. That is, after a polysilicon film is formed in a state in which the connection hole 13 is buried, the polysilicon film other than the inside of the connection hole 13 is removed by etch back or chemical mechanical polishing.
Then, a polysilicon plug 14 made of a polysilicon film is formed inside the semiconductor device 3.

Next, a stopper layer 31 covering the polysilicon plug 14 is formed on the interlayer insulating film 12 by depositing a titanium film by, for example, sputtering. Further, the insulating film 16 is formed on the stopper layer 31 by depositing silicon oxide by, for example, a chemical vapor deposition method. Then, the insulating film 16 and the stopper layer 31 are patterned using a normal lithography technique and an etching technique to form a concave portion 19 for forming a capacitor reaching the polysilicon plug 14. In this etching, the insulating film 16 can be etched with good controllability by using the stopper layer 31 as an etching stopper. After forming the concave portion 19 in the insulating film 16, the stopper layer 31 is continuously etched to form the concave portion 19 communicating with the polysilicon plug 14.

Next, the adhesion layer 15 is formed on the inner surface of the concave portion 19 and on the insulating film 16 in a laminated structure of a titanium film and a titanium nitride film. Further, the first electrode film 24 is formed by depositing tungsten. The formation of the adhesion layer 15 and the first electrode film 24 is performed such that a space remains in the recess 19. Subsequently, the mask insulating film 32 is formed of, for example, SOG (Spin on glass) or a resist film so as to fill the space. After that, the mask insulating film 32 is left only inside the concave portion 19 by a technique such as etch back. This mask insulating film 32 is formed of the adhesive layer 15 and the first electrode film 24.
And a polishing stopper during chemical mechanical polishing, and must be formed of a material having an etching selectivity with the insulating film 16 and a protective insulating film to be formed later.

Thereafter, as shown in FIG. 6 (2), the first electrode film 24 and the adhesive layer 15 are removed to a lower level than the insulating film 16 by, for example, chemical mechanical polishing or etch back, and the concave portion is formed. A first electrode 21 composed of a first electrode film 24 is formed on the inner surface of the substrate 19 with the adhesion layer 15 interposed therebetween.
At that time, the adhesion layer 15 is formed to be lower than the first electrode film 24. In this manner, the first electrode 21 including the bottomed cylindrical first electrode film 24 whose bottom and outside are wrapped by the adhesion layer 15 is formed.

Next, as shown in FIG. 6C, the cap insulating film 18 is covered with, for example, a silicon nitride film so as to cover the first electrode 21 and the adhesion layer 15 by, for example, chemical vapor deposition. Alternatively, it is formed using a silicon oxide film. Note that the cap insulating film 18 only needs to be covered with the adhesion layer 15, and may have a so-called sidewall shape. In addition, the cap insulating film 18 needs to be formed to a thickness such that the adhesion layer 15 is not exposed in a subsequent etching step. Therefore, the mask insulating film 32 is formed of a silicon nitride film or SOG (Spin on gl
When ass) is used, it can be formed of a silicon oxide film having a high selectivity with respect to the mask insulating film 32.

Thereafter, as shown in FIG. 6D, the mask insulating film 32 [see FIG. 6C] is selectively removed by etching or the like, and the recess 19 is opened again. Next, the dielectric film 2 is formed on the inner surface of the concave portion 19 and the cap insulating film 18 and the insulating film 16 by, for example, a chemical vapor deposition method.
2, for example, tantalum oxide (Ta ₂ O ₅ )
It is formed by depositing to a thickness of m. After that, 400 ° C ~ 45
The heat treatment is performed in an ozone or oxygen atmosphere at a temperature of about 0 ° C. Alternatively, heat treatment is performed in an ozone atmosphere under irradiation of ultraviolet rays. Thereafter, the recesses 19 are formed by chemical vapor deposition.
Is deposited and tungsten or tungsten nitride is deposited so as to cover the dielectric film 22 to form a second electrode 23 serving as a cell plate electrode. In this way,
A second electrode 23 is formed inside the first electrode 21 via a dielectric film 22.

In the third method of manufacturing a semiconductor device, when the dielectric film 22 is formed, the adhesion layer 15 and the dielectric film are separated from each other by the insulating film 16, the cap insulating film 19, and the first electrode 23. And the dielectric film 2
It is not oxidized by the oxygen contained in 2. Further, since the adhesion layer 15 is covered with the insulating film 16 and the like, even if heat treatment is performed in an oxidizing atmosphere for improving the characteristics of the dielectric film 22, the adhesion layer 15 is kept in the oxidizing atmosphere. It is not oxidized because it does not touch.

[0068]

As described above, according to the semiconductor device of the present invention, since the adhesion layer and the dielectric film are formed apart from each other, the dielectric film is made of a metal oxide and has a high dielectric constant. Even if it is formed of a body material, the adhesion layer portion is not oxidized by oxygen contained in the dielectric film. Therefore, an increase in leakage current in the contact layer due to oxidation of the contact layer does not occur, and the electrical characteristics do not deteriorate. Therefore, a highly reliable capacitor is realized.

According to the first manufacturing method of the present invention, at the stage when the dielectric film is formed, the adhesion layer and the dielectric film are separated from the insulating film,
It can be formed in a state separated by the sidewall and the first electrode. According to the second manufacturing method of the present invention, at the stage when the dielectric film is formed, the adhesion layer and the dielectric film can be formed in a state separated by the insulating film and the first electrode. . Further, according to the third manufacturing method of the present invention, at the stage when the dielectric film is formed, the adhesion layer and the dielectric film are formed so as to be separated by the insulating film, the cap insulating film, and the first electrode. be able to.
Therefore, the adhesion layer is not oxidized by oxygen contained in the dielectric film. Further, since the adhesion layer is covered with an insulating film or the like, even if heat treatment is performed in an oxidizing atmosphere for improving the characteristics of the dielectric film, the adhesion layer does not come into contact with the oxidizing atmosphere. So it is not oxidized. Therefore, a semiconductor device including a highly reliable capacitor having excellent electric characteristics can be formed.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a first embodiment according to a semiconductor device of the present invention.

FIG. 2 is a schematic configuration sectional view showing a second embodiment according to the semiconductor device of the present invention.

FIG. 3 is a schematic configuration sectional view showing a third embodiment according to the semiconductor device of the present invention.

FIG. 4 is a manufacturing process sectional view showing an embodiment according to a first manufacturing method of the present invention.

FIG. 5 is a manufacturing process sectional view showing an embodiment according to a second manufacturing method of the present invention.

FIG. 6 is a manufacturing process sectional view showing an embodiment according to a third manufacturing method of the present invention.

FIG. 7 is a manufacturing process diagram showing a first conventional technique relating to a method of manufacturing a capacitor having an MIM structure.

FIG. 8 is a manufacturing process diagram showing a second conventional technique relating to a method of manufacturing a capacitor having an MIM structure.

[Explanation of symbols]

15 adhesion layer, 21 first electrode, 22 dielectric film, 2
3. Second electrode

Claims (9)

[Claims] 1. A first cylindrical electrode having a bottom, a dielectric film formed on at least an inner surface of the first electrode, and at least inside the first electrode via the dielectric film. In the semiconductor device provided with the formed second electrode, an adhesion layer is provided at least at a bottom portion of the first electrode, and the adhesion layer and the dielectric film are formed in a separated state. Characteristic semiconductor device. 2. The adhesive layer is formed on a bottom of the first electrode, the dielectric film is formed on an inner surface of and above the first electrode, and the second electrode is formed on the dielectric film. 2. The semiconductor device according to claim 1, wherein said semiconductor device is formed inside and above said first electrode. 3. The adhesion layer is formed on the bottom of the first electrode, the dielectric film is formed continuously on the inner surface and the outer surface of the first electrode, and the second electrode is formed on the inner surface of the first electrode. 2. The semiconductor device according to claim 1, wherein the semiconductor device is formed continuously on an inner surface and an outer surface of the first electrode via a dielectric film. 4. The adhesion layer is continuously formed on a bottom portion and an outer surface of the first electrode, the dielectric film is formed on an inner surface of the first electrode and an upper portion thereof, and 2. The semiconductor device according to claim 1, wherein the electrode is formed inside and above the first electrode via the dielectric film. 5. A step of forming a columnar first electrode pattern on a substrate via an adhesion layer, and insulating between the first electrode patterns on the substrate so as to be higher than the first electrode pattern. A step of embedding with a film, a step of forming a sidewall made of an insulating film on an upper side periphery of the first electrode pattern, and etching the first electrode pattern by using the sidewall as a mask to form the first electrode pattern. Forming a cylindrical first electrode having a bottom with an electrode pattern; forming a dielectric film on at least the inner surface of the first electrode; forming a second electrode covering the dielectric film A method for manufacturing a semiconductor device, comprising: 6. The dielectric film includes an inner surface of the first electrode,
6. The semiconductor device according to claim 5, wherein the second electrode is formed on the sidewall and the insulating film, and the second electrode is formed inside the first electrode and on the dielectric film via the dielectric film. The manufacturing method of the semiconductor device described in the above. 7. A step of forming a columnar first electrode pattern on a substrate via an adhesion layer, and insulating between the first electrode patterns on the substrate so as to be higher than the first electrode pattern. A step of embedding with a film, a step of forming a sidewall made of an insulating film on an upper side periphery of the first electrode pattern, and etching the first electrode pattern by using the sidewall as a mask to form the first electrode pattern. A step of forming a cylindrical first electrode having a bottom with an electrode pattern; a step of removing the insulating film while maintaining a state where the insulating film covers a side surface of the adhesion layer; and a step of removing the first electrode. Forming a dielectric film on the inner surface and the outer surface thereof; and forming a second electrode on the inner surface and the outer surface of the first electrode via the dielectric film. Manufacturing of semiconductor devices Method. 8. A step of forming a concave portion in the insulating film after forming an insulating film on the substrate; and forming a first electrode film on the inner surface of the concave portion through the close contact layer after forming a close contact layer. Forming, a step of embedding a mask insulating film inside the concave portion, removing the first electrode film and the adhesive layer in a state lower than the insulating film, and forming the adhesive layer on the inner surface of the concave portion. Forming a first electrode made of a first electrode film via a first electrode, forming a cap insulating film covering the first electrode and the adhesive layer, and selectively removing the mask insulating film And forming a dielectric film on at least the inner surface of the first electrode; and forming a second electrode on at least the inside of the first electrode via the dielectric film. A method for manufacturing a semiconductor device, comprising: 9. The method according to claim 1, wherein the dielectric film is formed on an inner surface of the first electrode,
2. The semiconductor device according to claim 1, wherein the second electrode is formed on the cap insulating film and the insulating film, and the second electrode is formed inside the first electrode and on the dielectric film via the dielectric film. 9. The method for manufacturing a semiconductor device according to item 8.