JPH1022464A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an excellent semiconductor device and manufacture thereof in which the electric property of a transistor is stabilized by recovery from interface damage while deterioration is not generated in characteristics of a capacitance element having a high dielectric film as a capacitance insulating film, by forming an insulating film on a wiring between wiring layers except for the portion on the capacitance element, then carrying out heat treatment, and then forming a protective film. SOLUTION: A third insulating film 18 covering first wirings 17a, 17b except for the portion on a capacitance element 10, and a fourth insulating film 22 made of a silicon oxide film or a silicon oxide fluoride film covering the portion on the capacitance element 10 and the third insulating film 18, are formed. In the third insulating film 18 and the fourth insulating film 22, second contact holes 23a, 23b extending to the first wirings 17a, 17b are formed. Through these second contact holes, second wirings 24a, 24b made of a conductive material, such as, Al, are formed. In addition, a protective film 14 covering these second wirings is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a built-in capacitive element using a ferroelectric film or a dielectric film having a high dielectric constant as a capacitive insulating film, a method of manufacturing the same, and in particular, a semiconductor device requiring multilayer wiring and It relates to the manufacturing method.

[0002]

2. Description of the Related Art In recent years, unwanted radiation, which is electromagnetic noise generated from electronic equipment, has become a major problem with the increase in the density of consumer electronic equipment. 2. Description of the Related Art A technique of incorporating a large-capacity capacitive element using a film (hereinafter, referred to as a high dielectric film) or a ferroelectric film as a capacitive insulating film in a semiconductor integrated circuit has attracted attention. Also, with the aim of commercializing a non-volatile RAM capable of unprecedented low operating voltage, high-speed writing and high-speed reading, a capacitive element using a ferroelectric film having spontaneous polarization characteristics as a capacitive insulating film is formed on a semiconductor integrated circuit. Technical developments for this are being actively pursued.

A conventional semiconductor device having a built-in capacitive element will be described below with reference to a sectional view of a main part shown in FIG. As shown in FIG. 11, an isolation oxide film 2 is formed on a silicon substrate 1, and a transistor including a diffusion layer 3, a gate insulating film 4, and a gate electrode 5 is formed in a region surrounded by the isolation oxide film 2. Have been. A first insulating film 6 is formed so as to cover these transistors, and a lower electrode 7, a capacitive insulating film 8 made of a high dielectric film, and a capacitive element made of an upper electrode 9 are formed on the first insulating film 6. 10 are formed. A second insulating film 15 such as a silicon oxide film to which phosphorus is added (hereinafter referred to as a PSG film) is formed so as to cover these capacitive elements 10. First insulating film 6 and second insulating film 6
In the insulating film 15, a contact hole 12a reaching the diffusion layer 3 of the transistor and a contact hole 12b reaching the lower electrode 7 and the upper electrode 9 of the capacitor 10 are formed. Wirings 13a and 13b are formed via these contact holes 12a and 12b. Further, a protective film 14 is formed on the silicon substrate 1 so as to cover these elements.

Next, a method of manufacturing a conventional semiconductor device having a built-in capacitive element will be described with reference to a flowchart shown in FIG. 12 together with a sectional view of a main part shown in FIG.
First, in a step of FIG. 12A, an isolation oxide film 2, a diffusion layer 3, a gate insulating film 4, and a gate electrode 5 are formed on a silicon substrate 1, and further thereon, a step of FIG. One insulating film 6 is formed. Next, in the step of FIG. 12C, the lower electrode 7, the capacitor insulating film 8 and the upper electrode 9 are formed on the first insulating film 6.
Is formed. Generally, capacitance insulating film 8
Is performed immediately after forming the capacitive insulating film 8 or after forming the pattern of the capacitive element 10. The capacitance insulating film 8 is made of a high dielectric film, and has a lower electrode 7 and an upper electrode 9.
Is composed of a platinum film and a titanium film in order from the side in contact with the capacitance insulating film 8. Next, in the step of FIG. 12D, a second insulating film 15 such as a PSG film is formed on the entire surface by a CVD method or the like. Next, in the step of FIG. 12E, a contact hole 12a leading to the diffusion layer 3 of the transistor, and a contact hole 12b reaching the lower electrode 7 and the upper electrode 9 of the capacitor 10, respectively, are formed. Next, in the step of FIG. 12F, a wiring 13a connected to the diffusion layer 3 via the contact hole 12a and a wiring 13b connected to the capacitor 10 via the contact hole 12b are formed. Next, FIG.
In step 2 (g), the protective film 14 is formed. Protective film 14
As the silicon substrate 1, the capacitive element 10 and the wiring 1
Plasma C to prevent water from entering 3a, 13b
A highly moisture-resistant silicon nitride film or a silicon nitride oxide film formed by a VD method is used.

[0005]

Generally, in the process of manufacturing a MOS transistor, heat treatment is performed in a hydrogen atmosphere in order to recover damage at an interface between a silicon substrate and an insulating film formed thereon, particularly a gate insulating film. Process (hereinafter,
A hydrotreating step) is essential. However, in a semiconductor device including a capacitive element using a high dielectric film as a capacitive insulating film, there is a problem that the high dielectric film is deteriorated in the hydrogen treatment process. As a countermeasure,
As disclosed in JP-A-7-226443, a capacitive element is formed on a support substrate on which integrated circuit elements are formed, and then an interlayer insulating film is formed on the entire surface of the support substrate. By forming a contact hole reaching the diffusion layer of the integrated circuit element in the insulating film and performing a hydrogen treatment process on the support substrate in this state, hydrogen is supplied to the integrated circuit element region through the contact hole, so that a damaged portion is formed. There is known a method in which hydrogen easily reaches a high dielectric film because a hydrogen easily reaches the capacitor element region and no contact hole is formed in the capacitor element region.

However, in a semiconductor device requiring a multi-layer wiring, the above-described method is applicable only before the step of forming the first wiring, and is not applicable to the interface of the MOS transistor generated in the manufacturing steps after the formation of the first wiring. The problem is that the damage cannot be recovered. In addition, although it is difficult for hydrogen to reach the high-dielectric film by the above method, it is virtually impossible to completely prevent the arrival of hydrogen. When a material that causes remarkable occurrence is used as the capacitor insulating film, there is a problem that some deterioration of the characteristics of the capacitor is inevitable.

SUMMARY OF THE INVENTION In order to solve the above-mentioned conventional problems, the present invention provides a semiconductor device having a multilayer wiring and a built-in capacitive element using a ferroelectric film or a high dielectric film as a capacitive insulating film. It is an object of the present invention to provide a semiconductor device in which electric characteristics of a transistor are stabilized and a characteristic of a capacitor using a ferroelectric film or a high dielectric film as a capacitor insulating film is not deteriorated, and a method of manufacturing the same.

[0008]

In order to achieve the above object, a first semiconductor device according to the present invention comprises a lower electrode on a first insulating film of a support substrate on which a semiconductor integrated circuit is formed.
A capacitive element comprising a ferroelectric film or a dielectric film having a high dielectric constant and a capacitive element comprising an upper electrode; a second insulating film covering the capacitive element; and a second insulating film. A first wiring electrically connected to the semiconductor integrated circuit or the capacitor via a first contact hole, the semiconductor device including at least a part of the capacitor except for at least a part of the capacitor; A third insulating film covering the first wiring, a fourth insulating film covering the third insulating film,
A second insulating film provided on the third insulating film and the fourth insulating film;
A second wiring that is electrically connected to the first wiring via the contact hole, and a protective film that covers the second wiring. According to the present invention, since the insulating film is formed on the wiring except for the capacitor between the wiring layers and between the wiring layers, and the protective film is formed after the heat treatment, the electrical characteristics of the transistor are stabilized by the recovery of the interface damage. In addition, it is possible to realize an excellent semiconductor device in which characteristics of a capacitor using a high dielectric film as a capacitor insulating film are not deteriorated. That is,
Hydrogen contained in the third insulating film diffuses into the transistor portion, recovers damage at the interface of the transistor, thereby stabilizing its electrical characteristics, and forms the third insulating film on the capacitor. Since there is no film, it is possible to prevent the electrical characteristics of the capacitor from deteriorating due to the hydrogen contained in the third insulating film reaching the capacitor.
Thus, a semiconductor device having excellent electric characteristics can be obtained.

In the above semiconductor device, the third insulating film is at least one selected from a silicon nitride film, a silicon nitride oxide film, and a multilayer film having at least one of a silicon nitride film and a silicon nitride oxide film as a component. It is preferably one. According to this preferred example, a silicon nitride film or a silicon nitride oxide film contains a larger amount of hydrogen contained in the film than a film used in another semiconductor process such as a silicon oxide film, and therefore, in particular, has stable transistor characteristics. Conversion is easy.

Next, a second semiconductor device according to the present invention comprises a lower electrode, a ferroelectric film or a dielectric material having a high dielectric constant on a first insulating film of a support substrate on which a semiconductor integrated circuit is formed. A capacitive element comprising a capacitive insulating film made of a film and an upper electrode; a second insulating film covering the capacitive element;
A semiconductor device including a first wiring electrically connected to the semiconductor integrated circuit or the capacitor via a first contact hole provided in the insulating film, wherein a first wiring covering the first wiring is provided. A second wiring electrically connected to the first wiring via a second contact hole provided in the third insulating film; A fourth insulating film covering the second wiring;
A protection film for covering the fourth insulating film; According to this configuration, the hydrogen contained in the fourth insulating film diffuses into the transistor portion, thereby recovering the damage of the interface of the transistor, thereby stabilizing the electrical characteristics thereof, and forming the transistor on the capacitive element. Since there is no fourth insulating film, it is possible to prevent deterioration of electrical characteristics of the capacitor due to hydrogen contained in the fourth insulating film reaching the capacitor. As a result, a semiconductor device having excellent electric characteristics can be obtained.

In the semiconductor device, the fourth insulating film may be at least one selected from a silicon nitride film, a silicon nitride oxide film, and a multilayer film having at least one of a silicon nitride film and a silicon nitride oxide film. It is preferred that According to this preferred example, a silicon nitride film or a silicon nitride oxide film contains a larger amount of hydrogen contained in the film than a film used in another semiconductor process such as a silicon oxide film, and therefore, in particular, has stable transistor characteristics. Conversion is easy.

In the first and second semiconductor devices, it is preferable that the dielectric film contains a ferroelectric containing bismuth. According to this preferred example, since the ferroelectric substance containing bismuth is particularly severely deteriorated in characteristics due to hydrogen, a semiconductor device in which the electric characteristics of the capacitor are not deteriorated by this structure can be obtained. As a ferroelectric containing bismuth, for example, B
_{aBi 2 Ta x Nb 2-x} O 9, Bi 4 Ti 3 O 12, SrBi 2
_{Ta x Nb 2-x O 9} , SrBi 4 Ti 4 O 15, PbBi 2 Ta
_{x Nb 2-x O 9,} PbBi 4 Ti 4 O 15, Sr x Ba y Pb
_2-xy Bi ₄ Ti ₅ O ₁₈ (however, 0 ≦ x ≦ 2, 0 ≦ x +
Preferably, it is at least one compound selected from y ≦ 2).

Next, in a first manufacturing method of the present invention, a step of forming a first insulating film on a support substrate on which a semiconductor integrated circuit is formed, and a step of forming a predetermined insulating film on the first insulating film Forming a capacitive insulating film composed of a lower electrode, a ferroelectric film or a dielectric film having a high dielectric constant and a capacitive element composed of an upper electrode in a region, and forming a second insulating film covering the capacitive element Forming a first contact hole reaching the upper electrode and lower electrode of the semiconductor integrated circuit or the capacitor through the first insulating film and the second insulating film; Forming a first wiring electrically connected to the semiconductor integrated circuit or the capacitor element through a contact hole, wherein a third wiring covering the first wiring is formed. The process of forming an insulating film Removing the third insulating film on the capacitive element, heat-treating the third insulating film, and forming a fourth insulating film covering the third insulating film; Forming a second contact hole that reaches the first wiring through the third insulating film and the fourth insulating film; and electrically connects the first wiring through the second contact hole. And a step of forming a protection film covering the second wiring. According to this method, the semiconductor device of the present invention can be efficiently and rationally manufactured.

[0014] In the above method, the third insulating film is at least one selected from a silicon nitride film, a silicon nitride oxide film, and a multilayer film having at least one of a silicon nitride film and a silicon nitride oxide film as a constituent element. It is preferable that the film has a heat treatment temperature of 300 ° C. or higher and lower than the melting point of the material of the first wiring. According to this preferred example, the silicon nitride film or the silicon nitride oxide film contains a larger amount of hydrogen contained in the film than a film used in another semiconductor process such as a silicon oxide film. There is an advantage that the heat treatment temperature for diffusing hydrogen from the film can be lowered.

Next, in a second manufacturing method of the present invention, a step of forming a first insulating film on a supporting substrate on which a semiconductor integrated circuit is formed, and a step of forming a predetermined insulating film on the first insulating film Forming a capacitive insulating film composed of a lower electrode, a ferroelectric film or a dielectric film having a high dielectric constant and a capacitive element composed of an upper electrode in a region, and forming a second insulating film covering the capacitive element Forming a first contact hole reaching the upper electrode and lower electrode of the semiconductor integrated circuit or the capacitor through the first insulating film and the second insulating film; Forming a first wiring electrically connected to the semiconductor integrated circuit or the capacitor element through a contact hole, wherein a third wiring covering the first wiring is formed. Forming an insulating film; Forming a second contact hole reaching the first wiring through the third insulating film; and a second wiring electrically connected to the first wiring via the second contact hole. Forming a fourth insulating film covering the second wiring, removing at least the fourth insulating film over the capacitor, and removing the fourth insulating film. Performing a heat treatment;
Forming a protective film covering the insulating film. According to the method, hydrogen contained in the fourth insulating film is diffused into the transistor portion by the heat treatment, and the electrical characteristics are stabilized by recovering the damage of the interface of the transistor. Does not have the fourth insulating film, it is possible to prevent deterioration of the electrical characteristics of the capacitor due to the hydrogen contained in the fourth insulating film reaching the capacitor during heat treatment. As a result, a semiconductor device having excellent electric characteristics can be obtained.

In the above method, the fourth insulating film may be a silicon nitride film, a silicon nitride oxide film, and a multilayer film having at least one of a silicon nitride film and a silicon nitride oxide film as a constituent element. Is above 300 ° C,
It is preferably lower than the melting point of the material of the first wiring or the second wiring. According to this preferred example, the silicon nitride film or the silicon nitride oxide film contains a larger amount of hydrogen contained in the film than a film used in another semiconductor process such as a silicon oxide film. The heat treatment temperature for hydrogen diffusion from the film can be lowered.

In the first and second methods,
Preferably, the dielectric film is a ferroelectric containing bismuth. Bismuth-containing ferroelectrics are particularly severely degraded in characteristics due to hydrogen, and thus the present manufacturing method can provide a semiconductor device in which electric characteristics of a capacitor are not degraded. The ferroelectric containing bismuth, e.g., _{BaBi 2 Ta x Nb 2-x} O 9, B
_{i 4 Ti 3 O 12, SrBi} 2 Ta x Nb 2-x O 9, SrBi 4
_{Ti 4 O 15, PbBi 2 Ta} x Nb 2-x O 9, PbBi 4 Ti
_{4 O 15, Sr x Ba y} Pb 2-xy Bi 4 Ti 5 O 18 ( where
It is preferably at least one compound selected from 0 ≦ x ≦ 2, 0 ≦ x + y ≦ 2).

As described above, according to the present invention, in a semiconductor device having a built-in capacitance element using a ferroelectric film or a high-dielectric film having a multi-layer wiring as a capacitance insulating film, after forming the multi-layer wiring, It has been found that a semiconductor device having excellent electrical characteristics can be obtained by forming a protective film after forming an insulating film on a wiring except on an element and heat-treating it.

[0019]

Embodiments of the present invention will be described below. In the following description of the drawings, the same parts as those in the cross-sectional view of the principal part of a conventional single-layer wiring semiconductor device having a built-in capacitance element will be denoted by the same reference numerals, and description thereof will be omitted.

(Embodiment 1) One embodiment of a semiconductor device having a built-in capacitive element and having a multilayer wiring will be described with reference to a cross-sectional view of a main part shown in FIG.

In the first insulating film 6 and the second insulating film 15, a first contact hole 16a reaching the diffusion layer 3 of the transistor and a first contact hole reaching the lower electrode 7 and the upper electrode 9 of the capacitive element 10. 16b are formed. Through these first contact holes 16a and 16b, the first wiring 1 is made of a conductive material such as Al or Cu.
7a and 17b are formed. These first wirings 1
A third insulating film 18 covering portions 7a and 17b and excluding portions on the capacitive element 10, and a silicon oxide film or fluorinated oxide covering the capacitive element 10 and the third insulating film 18; A fourth insulating film 22 such as a silicon film is formed. The third insulating film 18 and the fourth insulating film 22 have second contact holes 23 reaching the first wirings 17a and 17b.
a and 23b are formed, and second wirings 24a and 24b are formed of a conductive material such as Al and Cu through the second contact holes 23a and 23b. Note that the second contact holes 23a and 23b are not shown in this cross-sectional view but are present in other portions. further,
Protective film 1 covering these second wirings 24a, 24b
4 are formed.

Here, as the third insulating film 18, a silicon nitride film, a silicon nitride oxide film, or the like is used. However, the present invention is not limited to this, and a film in which hydrogen is contained in the film is used. I just need. Further, the third insulating film 18 does not need to be a single-layer film, and may be, for example, a multilayer film having a sandwich structure in which a metal film having a hydrogen absorbing property is sandwiched between insulating films. Further, in the present embodiment, the number of wiring layers on the capacitive element 10 is two, and the third insulating film 18 is formed on the first wirings 17a and 17b. However, the present invention is not limited to this. Even when the number of wiring layers on the element 10 is three or more, the same effect can be obtained by forming the third insulating film 18 between the wiring layers.

(Embodiment 2) One embodiment of a method for manufacturing a semiconductor device having a multilayer wiring with a built-in capacitance element will be described.
This will be described with reference to a flowchart shown in FIG. 2 together with a cross-sectional view of a main part shown in FIG. 2 is different from the flowchart of the conventional single-layer wiring semiconductor device shown in FIG.
(E) In the subsequent steps. That is, FIG.
In the step (d), a transistor including the diffusion layer 3, the gate insulating film 4, and the gate electrode 5 is formed on the silicon substrate 1, and the lower electrode 7 and the capacitor are formed on the first insulating film 6 covering the transistor. After forming the capacitive element 10 including the insulating film 8 and the upper electrode 9, a second insulating film 15 is formed on the entire surface. Next, in the step of FIG. 2E, a first contact hole 16a leading to the diffusion layer 3 of the transistor and a first contact hole 16b reaching the lower electrode 7 and the upper electrode 9 of the capacitor 10 are formed. Next, in the step of FIG.
The first wiring 17 connected to the diffusion layer 3 via the first contact hole 16a by a conductive material such as l, Cu, or the like.
a, and a first wiring 17b connected to the capacitor 10 via the first contact hole 16b. Next, a third insulating film 18 is formed in the step of FIG. The third insulating film 18 contains hydrogen in the film.
A silicon nitride film or a silicon nitride oxide film is used. Next, FIG.
In the step (h), the third insulating film 1 on the capacitive element 10
8 is removed and the third insulating film 18 is subjected to a heat treatment. Next, in the step of FIG. 2I, a fourth insulating film 22 such as a silicon oxide film is formed.
To form Next, in the step of FIG.
a, 2b reaching the second contact holes 23a, 23b
3b is formed. Next, in the step of FIG.
The second contact hole 23 is made of a conductive material such as
Second wirings 24a and 24b are formed which are electrically connected to first wirings 17a and 17b via a and 23b.

Next, in the step of FIG.
The protective film 14 is formed so as to cover a and 24b.
As the protective film 14, the silicon substrate 1, the capacitor 10, the first wirings 17a and 17b, and the second wiring 24
In order to prevent water from entering the a and b, a silicon nitride film or a silicon nitride oxide film having high moisture resistance is used. The preferred thickness of the silicon nitride film or silicon nitride oxide film is 60
It is 0 nm to 1000 nm.

Here, as the third insulating film 18, a silicon nitride film, a silicon nitride oxide film, or the like is used, but the present invention is not limited to this, and a film in which hydrogen is contained in the film is used. I just need. Further, the third insulating film 18 does not need to be a single-layer film, and may be, for example, a multilayer film having a sandwich structure in which a metal film having a hydrogen absorbing property is sandwiched between insulating films. Further, in the present embodiment, the number of wiring layers on the capacitive element 10 is two, and the third insulating film 18 is formed after the formation of the first wirings 17a and 17b. However, the present invention is not limited to this.
Even when the number of wiring layers on the capacitive element 10 is three or more,
Similar effects can be obtained by forming the third insulating film 18 between the wiring layers.

The conditions for the heat treatment of the third insulating film 18 can be a treatment in an inert gas such as nitrogen or argon, or in an oxygen atmosphere. In particular, it is preferable that the high dielectric film is composed of an oxide, because heat treatment in an oxygen atmosphere can improve characteristics of the high dielectric film in the capacitor.

(Embodiment 3) In the present invention, the third
The insulating film 18 uses a silicon nitride film, a silicon nitride oxide film, or a multilayer film having at least one of a silicon nitride film and a silicon nitride oxide film as a component. These films are particularly effective in terms of stabilizing transistor characteristics because the amount of hydrogen usually contained in the films is larger than that of films used in other semiconductor processes such as a silicon oxide film.

(Embodiment 4) In the present invention, the third
The insulating film 18 is a silicon nitride film, a silicon nitride oxide film, or a multilayer film having at least one of a silicon nitride film and a silicon nitride oxide film as a component, and a heat treatment temperature thereof is 300 ° C. or higher. Is what you do. These films are particularly effective in terms of stabilizing transistor characteristics because the amount of hydrogen usually contained in the films is larger than that of films used in other semiconductor processes such as a silicon oxide film. In particular, when the film is formed by the plasma CVD method, the effect is remarkable, and there is an advantage that the heat treatment can be performed at a low temperature.

FIG. 3 shows a thermal desorption spectrum of a silicon nitride film formed by the plasma CVD method, and it can be confirmed that hydrogen is released from the film at 300 ° C. or higher. However, if the heat treatment temperature is equal to or higher than the melting point of the material of the first wirings 17a and 17b, a problem occurs in the semiconductor device. Therefore, the heat treatment temperature is preferably 300 ° C. or higher and lower than the melting point of the wiring material. For example, if the wiring material is Al (melting point 660.4)
° C), the heat treatment temperature is 300 ° C or higher and 660.
Preferably less than 4 ° C. In addition, Cu (melting point 108
(3.4 ° C), the heat treatment temperature is 300 ° C or higher and 1
Preferably it is less than 083.4 ° C.

(Embodiment 5) One embodiment of a semiconductor device having a built-in capacitive element and having a multilayer wiring will be described with reference to a sectional view of a main part shown in FIG.

In the first insulating film 6 and the second insulating film 15, a first contact hole 16 a reaching the diffusion layer 3 of the transistor and a first contact hole reaching the lower electrode 7 and the upper electrode 9 of the capacitor 10. 16b are formed. Through these first contact holes 16a and 16b, the first wiring 1 is made of a conductive material such as Al or Cu.
7a and 17b are formed. These first wirings 1
A third insulating film 25 such as a silicon oxide film or a silicon oxyfluoride film is formed to cover 7a and 17b. In the third insulating film 25, second contact holes 19a and 19b reaching the first wirings 17a and 17b are formed.
Al, Cu via contact holes 19a, 19b of
The second wirings 20a and 20b are formed of a conductive material such as. Note that the second contact holes 19a, 1
9b is not shown in this cross-sectional view, but exists in another part. Further, a fourth insulating film 21 covering a portion except on the capacitor 10 and a protective film 14 covering the capacitor 10 and the fourth insulating film 21 are formed.

Here, as the fourth insulating film 21, a silicon nitride film, a silicon nitride oxide film, or the like is used. However, the present invention is not limited to this, and a film in which hydrogen is contained in the film is used. I just need. Further, the fourth insulating film 21 does not need to be a single-layer film, and may be, for example, a multilayer film having a sandwich structure in which a metal film having a hydrogen absorbing property is sandwiched between insulating films. Furthermore, in this embodiment, the number of wiring layers on the capacitor 10 is two, and the fourth insulating film 21 is formed on the second wiring 20a. However, the present invention is not limited to this.
Even when the upper wiring layer has three or more layers, the same effect can be obtained by forming the fourth insulating film 21 on the final wiring layer. Also, needless to say, the same effect can be obtained by forming the fourth insulating film 21 on the first wirings 17a and 17b even when the wiring layer on the capacitor 10 is one layer. Needless to say.

(Embodiment 6) One embodiment of a method of manufacturing a semiconductor device having a multilayer wiring with a built-in capacitance element will be described.
This will be described with reference to the flowchart shown in FIG. 7 together with the cross-sectional view of the main part shown in FIG. 7 is different from the flowchart of the conventional single-layer wiring semiconductor device shown in FIG.
(E) In the subsequent steps. That is, FIG.
In the step (d), a transistor including the diffusion layer 3, the gate insulating film 4, and the gate electrode 5 is formed on the silicon substrate 1, and the lower electrode 7 and the capacitor are formed on the first insulating film 6 covering the transistor. After forming the capacitive element 10 including the insulating film 8 and the upper electrode 9, a second insulating film 15 is formed on the entire surface. Next, in the step of FIG. 7E, a first contact hole 16a leading to the diffusion layer 3 of the transistor and a first contact hole 16b reaching the lower electrode 7 and the upper electrode 9 of the capacitor 10 are formed. Next, in the step of FIG.
The first wiring 17 connected to the diffusion layer 3 via the first contact hole 16a by a conductive material such as l, Cu, or the like.
a, and a first wiring 17b connected to the capacitor 10 via the first contact hole 16b is formed.
Next, in a step of FIG. 7G, a third insulating film 25 such as a silicon oxide film is formed. Next, in the step of FIG. 7H, the second contact holes 19 reaching the first wirings 17a and 17b are formed.
a and 19b are formed. Next, in the step of FIG.
The second wirings 20a and 20b that are electrically connected to the first wirings 17a and 17b through the second contact holes 19a and 19b are formed using a conductive material such as l or Cu. Next, in the step of FIG. 7J, a fourth insulating film 21 is formed. As the fourth insulating film 21, a silicon nitride film or a silicon nitride oxide film containing hydrogen in the film is used. Next, FIG.
In the step (k), the fourth insulating film 2 on the capacitive element 10
1 is removed, and the fourth insulating film 21 is subjected to a heat treatment. Next, in the step of FIG. 7 (l), the protection film 1 covering the fourth insulating film 21 is formed.
4 is formed. As the protective film 14, the silicon substrate 1, the capacitor 10, and the first wirings 17a, 17
In order to prevent water from entering the second wirings 20a and 20b, a silicon nitride film or a silicon nitride oxide film having high moisture resistance is used. A preferable thickness of the silicon nitride film, the silicon nitride oxide film, or the like is 600 nm to 1000 nm.

Here, a silicon nitride film, a silicon nitride oxide film, or the like is used as the fourth insulating film 21. However, the present invention is not limited to this, and a film containing hydrogen in the film may be used. I just need. Further, the fourth insulating film 21 does not need to be a single-layer film, and may be, for example, a multilayer film having a sandwich structure in which a metal film having a hydrogen absorbing property is sandwiched between insulating films. Furthermore, in the present embodiment, the number of wiring layers on the capacitive element 10 is two, and the fourth insulating film 21 is formed after the formation of the second wirings 20a and 20b. However, the present invention is not limited to this.
Even when the number of wiring layers on the capacitive element 10 is three or more,
A similar effect can be obtained by forming the fourth insulating film 21 after the formation of the final wiring layer. Naturally, even when the wiring layer on the capacitive element 10 is a single layer, the fourth insulating film 21 is formed on the first wirings 17a and 17b.
(I.e., the steps of FIGS. 7 (g) to 7 (i) are omitted) to obtain the same effect.

The conditions for the heat treatment of the fourth insulating film 21 are as follows. The treatment can be performed in an inert gas such as nitrogen or argon, or in an oxygen atmosphere. In particular, it is preferable that the high dielectric film is composed of an oxide, because heat treatment in an oxygen atmosphere can improve characteristics of the high dielectric film in the capacitor.

(Embodiment 7) In the present invention, the fourth
The insulating film 21 uses a silicon nitride film, a silicon nitride oxide film, or a multilayer film having at least one of a silicon nitride film and a silicon nitride oxide film as a component. These films are particularly effective in terms of stabilizing transistor characteristics because the amount of hydrogen usually contained in the films is larger than that of films used in other semiconductor processes such as a silicon oxide film.

(Embodiment 8) In the present invention, the fourth
Is a silicon nitride film, a silicon nitride oxide film, or a multilayer film having at least one of a silicon nitride film and a silicon nitride oxide film as a component, and a heat treatment temperature thereof is 300 ° C. or higher. Is what you do. These films are particularly effective in terms of stabilizing transistor characteristics because the amount of hydrogen usually contained in the films is larger than that of films used in other semiconductor processes such as a silicon oxide film. In particular, when the film is formed by the plasma CVD method, the effect is remarkable, and there is an advantage that the heat treatment can be performed at a low temperature.

FIG. 8 is a temperature-programmed desorption spectrum of a silicon nitride film formed by the plasma CVD method, and it can be confirmed that hydrogen is released from the film at 300 ° C. or higher.

However, when the heat treatment temperature is the first wiring 17a,
If the temperature of the material 17b or the material of the second wirings 20a and 20b is higher than the melting point, a problem occurs in the semiconductor device. Therefore, the heat treatment temperature is preferably 300 ° C. or higher and lower than the melting point of the wiring material. For example, Al (melting point 660.4 ° C) for wiring material
When using, the heat treatment temperature is 300 ° C or higher and 660.4 ° C
Less than is preferred. In addition, Cu (melting point 1083.
4 ° C.), the heat treatment temperature is 300 ° C. or more and 108 ° C.
Less than 3.4 ° C. is preferred.

(Embodiment 9) The present invention is characterized in that the dielectric film contains a ferroelectric containing bismuth. Bismuth-containing ferroelectrics are particularly severely degraded in characteristics due to hydrogen, and thus this structure has an effect of obtaining a semiconductor device in which electric characteristics of a capacitor are not degraded. Here, examples of the ferroelectric substance containing bismuth include the following. (1) BaBi ₂ Ta ₂ O ₉ (2) BaBi ₂ Nb ₂ O ₉ (3) Bi ₄ Ti ₃ O ₁₂ (4) SrBi ₂ Ta ₂ O ₉ (5) SrBi ₂ Nb ₂ O ₉ (6) SrBi ₄ Ti ₄ O ₁₅ (7) PbBi ₂ Ta ₂ O ₉ (8) PbBi ₂ Nb ₂ O ₉ (9) PbBi ₄ Ti ₄ O ₁₅ (10) Sr ₂ Bi ₄ Ti ₅ O ₁₈ (11) Ba ₂ Bi ₄ Ti ₅ O ₁₈ (12) Pb ₂ Bi ₄ Ti ₅ O _{18 In} addition to the above, for example, SrBi ₂ (Ta _1.5 Nb _0.5 ) O ₉
Naturally, a material in which a part of the material is replaced with another element such as, for example, can be used. Further, as the dielectric film, a single-layer / laminated film of a ferroelectric containing bismuth as described above, or a film of a mixture of a ferroelectric containing bismuth and an insulator such as SiO ₂ as described above may be used. Good.

[0041]

Next, the present invention will be described more specifically with reference to examples. (Embodiment 1) A semiconductor device according to an embodiment of the first invention of the present invention and a method of manufacturing the same will be described with reference to the cross-sectional view of the main part shown in FIG. A semiconductor device using a SrBi ₂ Ta ₂ O ₉ film (250 nm thick) as a dielectric film of the capacitor 10 was prototyped. After the first wirings 17a and 17b are formed by the procedure shown in (Embodiment 2), a third insulating film 18 (a silicon nitride film (thickness: 200 nm) is formed by a plasma CVD method) on the entire surface of the wafer. Then, the third insulating film 18 on the capacitor 10 was removed by etching, and heat treatment was performed at 450 ° C. in a nitrogen atmosphere. Thereafter, a fourth insulating film 22 is formed, and then the second contact holes 23a and 23b and the second wirings 24a and 24b are formed.
And a protective film 14 were formed. FIG. 4 shows the threshold voltage (at a drain current of 1 μA) of the n-channel transistor of the semiconductor device in this embodiment. FIG. 4 shows the steps from the formation of the third insulating film 18 to the heat treatment (FIGS.
Although the threshold voltage of an n-channel transistor of the same size in the semiconductor device in which (e) corresponds to (h) is omitted, the threshold voltage of the transistor according to the present invention is close to the design value of 0.8V. It can be seen that it takes a value. FIG. 5 shows the withstand voltage of the capacitor 10. In the present embodiment, the withstand voltage of the capacitive element 10 is 30 V or more, but the steps from the formation of the third insulating film 18 to the heat treatment (corresponding to FIGS. 2G to 2H) are omitted. In addition, when a hydrogen treatment step which is essentially indispensable in a transistor manufacturing process is performed after the formation of the protective film 14, the withstand voltage of the capacitive element 10 is 0 V (also shown in FIG. 5). It was confirmed that the characteristics of the capacitive element using as the capacitive insulating film did not deteriorate.

(Embodiment 2) A semiconductor device according to a second embodiment of the present invention and a method of manufacturing the same will be described with reference to FIG.
This will be described with reference to the cross-sectional views of the main parts shown in FIG.

SrBi ₂ as a dielectric film of the capacitor 10
A semiconductor device using a Ta ₂ O ₉ film (250 nm in thickness) was prototyped. After forming up to the second wirings 20a and 20b by the procedure shown in (Embodiment 6), the fourth insulating film 21 is formed.
(A silicon nitride film (thickness: 400 nm) formed by a plasma CVD method) is formed on the entire surface of the wafer, the fourth insulating film 21 on the capacitor 10 is removed by etching, and heat treatment is performed at 450 ° C. in a nitrogen atmosphere. Then, a protective film 14 was formed. FIG. 9 shows the threshold voltage (drain current of 1 μA) of the n-channel transistor of the semiconductor device in this embodiment.
Hour). FIG. 9 also shows a threshold voltage of an n-channel transistor of the same size in a semiconductor device in which steps from formation of the fourth insulating film 21 to heat treatment (corresponding to FIGS. 7J to 7K) are omitted. It is also shown that the threshold voltage of the transistor according to the present invention takes a value near the designed value of 0.8V. FIG.
Shows the breakdown voltage of the capacitor 10. In this embodiment, the withstand voltage of the capacitive element 10 is 30 V or more, while the steps from the formation of the fourth insulating film 21 to the heat treatment (FIG. 7 (j) to FIG.
(Corresponding to (k)) is omitted, and the hydrogen treatment step which is essentially indispensable in the transistor manufacturing process is performed by the protective film 14.
When implemented after formation, the withstand voltage of the capacitive element 10 is 0 V (also shown in FIG. 10), and it is confirmed that the characteristic deterioration of the capacitive element using the high dielectric film as the capacitive insulating film according to the present invention does not occur. It could be confirmed.

[0044]

As described above, according to the first semiconductor device and the method of manufacturing the same of the present invention, the capacitance element having the ferroelectric film or the high dielectric film having the multilayer wiring as the capacitance insulating film is incorporated. In a semiconductor device, an insulating film is formed on a wiring except for a capacitor between wiring layers and between wiring layers, and a protective film is formed after heat treatment, so that electrical characteristics of the transistor are stabilized by recovery of interface damage, In addition, it is possible to realize an excellent semiconductor device and a method of manufacturing the same, which do not cause deterioration in characteristics of a capacitor using a high dielectric film as a capacitor insulating film.

According to the second semiconductor device and the method of manufacturing the same of the present invention, in a semiconductor device having a built-in capacitive element using a ferroelectric film or a high dielectric film having a multilayer wiring as a capacitive insulating film, After forming the wiring, an insulating film is formed on the wiring except on the capacitive element, and after a heat treatment, a protective film is formed, so that the electrical characteristics of the transistor are stabilized by the recovery of the interface damage, and the high dielectric film is formed. And a method for manufacturing the same, which does not cause deterioration of the characteristics of the capacitive element using the capacitor as a capacitive insulating film.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an embodiment of a first semiconductor device of the present invention.

FIG. 2 is a flowchart of the same manufacturing process.

FIG. 3 is a diagram showing a temperature-induced desorption amount of hydrogen from a silicon nitride film formed by a plasma CVD method.

FIG. 4 is a diagram showing a threshold voltage of an n-channel transistor in one embodiment of the first semiconductor device of the present invention and a conventional example.

FIG. 5 is a diagram showing a breakdown voltage of a capacitive element in one embodiment of the first semiconductor device of the present invention and a conventional example.

FIG. 6 is an essential part cross-sectional view of one embodiment of a second semiconductor device of the present invention;

FIG. 7 is a flowchart of the manufacturing process.

FIG. 8 is a diagram showing the amount of thermal desorption of hydrogen from a silicon nitride film formed by a plasma CVD method.

FIG. 9 is a diagram showing a threshold voltage of an n-channel transistor in one embodiment of the second semiconductor device of the present invention and a conventional example.

FIG. 10 is a diagram showing the breakdown voltage of a capacitor in one embodiment of the second semiconductor device of the present invention and a conventional example.

FIG. 11 is a sectional view of a main part of a conventional semiconductor device.

FIG. 12 is a flowchart of a conventional semiconductor device manufacturing process.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Silicon substrate (supporting substrate) 2 Separation oxide film 3 Diffusion layer 4 Gate insulating film 5 Gate electrode 6 First insulating film 7 Lower electrode 8 Capacitive insulating film 9 Upper electrode 10 Capacitance elements 12a, 12b Contact holes 13a, 13b Wiring 14 Protective film 15 Second insulating film 16a, 16b First contact hole 17a, 17b First wiring 18, 25 Third insulating film 19a, 19b, 23a, 23b Second contact hole 20a, 20b, 24a, 24b Second wiring 21, 22 Fourth insulating film

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication location H01L 21/8247 29/788 29/792 (72) Inventor Nohisa Nagano No. 1 Yukicho, Takatsuki-shi, Osaka No. 1 Matsushita Electronics Co., Ltd. (72) Inventor Akihiro Matsuda 1-1, Sachimachi, Takatsuki-shi, Osaka Matsushita Electronics Co., Ltd.

Claims (12)

[Claims] 1. A capacitor insulating film comprising a lower electrode, a ferroelectric film or a dielectric film having a high dielectric constant and an upper electrode on a first insulating film of a support substrate on which a semiconductor integrated circuit is formed. A capacitor element, a second insulating film covering the capacitor element, and a first contact hole provided in the second insulating film, electrically connected to the semiconductor integrated circuit or the capacitor element. A first insulating film that covers the first wiring except for at least a part of the capacitor, and a third insulating film that covers the third insulating film. A fourth insulating film, a second wiring electrically connected to the first wiring via a second contact hole provided in the third insulating film and the fourth insulating film, A semiconductor device provided with a protective film for covering a second wiring. 2. The method according to claim 1, wherein the third insulating film is at least one selected from a silicon nitride film, a silicon nitride oxide film, and a multilayer film including at least one of a silicon nitride film and a silicon nitride oxide film. Item 2. The semiconductor device according to item 1. 3. A capacitor insulating film comprising a lower electrode, a ferroelectric film or a dielectric film having a high dielectric constant and an upper electrode on a first insulating film of a support substrate on which a semiconductor integrated circuit is formed. A capacitor, a second insulating film covering the capacitor, and a first contact hole provided in the second insulating film, and electrically connected to the semiconductor integrated circuit or the capacitor. A semiconductor device provided with a first wiring, wherein a third insulating film covering the first wiring;
A second wiring electrically connected to the first wiring via a second contact hole provided in the insulating film, and a fourth wiring covering at least the second wiring except on the capacitor. A semiconductor device, comprising: an insulating film according to any one of the above, and a protective film covering the fourth insulating film. 4. The fourth insulating film is at least one selected from a silicon nitride film, a silicon nitride oxide film, and a multilayer film having at least one of a silicon nitride film and a silicon nitride oxide film as a constituent element. 4. The semiconductor device according to 3. 5. The semiconductor device according to claim 1, wherein the dielectric film includes a ferroelectric containing bismuth. 6. The ferroelectric substance containing bismuth is made of BaBi._Two
Ta_xNb_2-xO₉, Bi _FourTi_ThreeO₁₂, SrBi_TwoTa_xN
b_2-xO₉, SrBi_FourTi_FourO_Fifteen, PbBi_TwoTa_xNb
_2-xO₉, PbBi_FourTi_FourO_Fifteen, Sr_xBa_yPb_2-xyB
i_FourTi_FiveO₁₈(However, 0 ≦ x ≦ 2, 0 ≦ x + y ≦ 2)
The compound according to claim 5, which is at least one compound selected from the group consisting of:
13. The semiconductor device according to claim 1. 7. A step of forming a first insulating film on a support substrate on which a semiconductor integrated circuit is formed, and forming a lower electrode, a ferroelectric film or a high-density film on a predetermined region on the first insulating film. A step of forming a capacitive insulating film composed of a dielectric film having a dielectric constant and a capacitive element composed of an upper electrode; a step of forming a second insulating film covering the capacitive element; Forming a first contact hole reaching an upper electrode and a lower electrode of the semiconductor integrated circuit or the capacitor through a second insulating film; and forming the first integrated circuit through the first contact hole. Forming a first wiring electrically connected to a capacitance element, the method comprising: forming a third insulating film covering the first wiring; and forming at least the capacitor The third isolation on the device Removing the edge film, heat-treating the third insulating film, forming a fourth insulating film covering the third insulating film, forming the third insulating film and the fourth insulating film. Forming a second contact hole reaching the first wiring through the insulating film; and forming a second wiring electrically connected to the first wiring via the second contact hole. A method for manufacturing a semiconductor device, comprising: a forming step; and a step of forming a protective film covering the second wiring. 8. The third insulating film is at least one film selected from a silicon nitride film, a silicon nitride oxide film, and a multilayer film having at least one of a silicon nitride film and a silicon nitride oxide film as a component. 8. The method according to claim 7, wherein the heat treatment temperature is 300 ° C. or higher and lower than the melting point of the material of the first wiring. 9. A step of forming a first insulating film on a supporting substrate on which a semiconductor integrated circuit is formed, and a step of forming a lower electrode, a ferroelectric film or a high-density film on a predetermined region on the first insulating film. A step of forming a capacitive insulating film composed of a dielectric film having a dielectric constant and a capacitive element composed of an upper electrode; a step of forming a second insulating film covering the capacitive element; Forming a first contact hole reaching an upper electrode and a lower electrode of the semiconductor integrated circuit or the capacitor through a second insulating film; and forming the first integrated circuit through the first contact hole. Forming a first wiring electrically connected to a capacitive element, the method comprising: forming a third insulating film covering the first wiring; The first wiring through the insulating film of Forming a second contact hole reaching the first wire, forming a second wire electrically connected to the first wire through the second contact hole, and forming the second wire through the second contact hole. Forming a fourth insulating film overlying, removing at least the fourth insulating film over the capacitor, heat treating the fourth insulating film, and removing the fourth insulating film. A method for manufacturing a semiconductor device, comprising a step of forming a protective film by covering. 10. The fourth insulating film is a silicon nitride film, a silicon nitride oxide film, and a multilayer film having at least one of a silicon nitride film and a silicon nitride oxide film as a component, and a heat treatment temperature of 300 ° C. The method according to claim 9, wherein the melting point is lower than the melting point of the material of the first wiring or the second wiring. 11. The method for manufacturing a semiconductor device according to claim 7, wherein the dielectric film is a ferroelectric containing bismuth. 12. The ferroelectric material containing bismuth is made of BaBi.
_{2 Ta x Nb 2-x O} 9, Bi 4 Ti 3 O 12, SrBi 2 Ta x N
_{b 2-x O 9, SrBi} 4 Ti 4 O 15, PbBi 2 Ta x Nb
_{2-x O 9, PbBi 4} Ti 4 O 15, Sr x Ba y Pb 2-xy B
i ₄ Ti ₅ O ₁₈ (however, 0 ≦ x ≦ 2, 0 ≦ x + y ≦ 2)
12. At least one compound selected from the group consisting of:
13. The method for manufacturing a semiconductor device according to item 5.