JPH07153840A - Semiconductor device and its manufacture - Google Patents

Abstract

PURPOSE:To simplify the foaming process of an ozone TEOS film as an interlayer insulating film, and obtain a semiconductor device whose film quality is improved and its manufacturing method. CONSTITUTION:On a silicon substrate 1, a BPSG film 2 as a first base insulating film is formed, and thereon a plasma silicon film 3 as a second base insulating film is formed by a silane plasma CVD method. After an aluminum wiring 4 having a necessary pattern is formed on the base insulating film 3, a silicon oxide film (ozone TEOS film) 5 is formed by a high ozone concentration organic silane.ozone based normal pressure CVD method. An organic silica film is stuck to the silicon oxide film 5, and the surface is flattened by etch back. A silicon oxide film (plasma TEOS film) 7 is formed on the flattened ozone TEOS film 5 by an organic silane CVD method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device in which an interlayer insulating film is formed on a wiring formed on a lower insulating film, and more particularly to a structure of the lower insulating film and the interlayer insulating film and a manufacturing method thereof.

[0002]

2. Description of the Related Art In a conventional semiconductor device having high integration, a wiring is formed on a lower insulating film, and an interlayer insulating film is formed on the lower insulating film to form an upper wiring. Has been adopted. As this interlayer insulating film, there is used atmospheric pressure chemical vapor deposition (CV) using ethyl silicate (Si (OC ₂ H ₅ ) ₄ : hereinafter referred to as TEOS) and ozone.
A silicon oxide film (hereinafter referred to as an ozone TEOS film) formed by using the method D) is used. In this ozone TEOS film, the underlying insulating film is polysilicon (polycrystalline silicon).
The film is excellent in flatness of the surface, but when the underlying insulating film is a thermal oxide film, unevenness may occur on the surface. Further, the higher the ozone concentration at the time of forming the ozone TEOS film, the larger the difference in the unevenness of the surface tends to be due to the influence of aluminum forming the underlying wiring. Therefore, stress is applied to the wiring formed on the uneven surface of the ozone TEOS film, and disconnection or the like is likely to occur, which may deteriorate reliability.

For this reason, Japanese Patent Laid-Open No. 3-198340 proposes a method of manufacturing an interlayer insulating film in which the surface of the ozone TEOS film is flattened. This method is shown in FIG. First, as shown in FIG. 4A, the silicon substrate 11 is heat-treated to form a gate oxide film 12 of 0.02 μm on its surface.
After being formed and polysilicon is deposited thereon by the CVD method, patterning is performed to form a polysilicon film 13 constituting a gate electrode and the like. Next, as shown in FIG.
Set the ozone concentration to about 1% and set the ozone TEOS film (1
%) 14 is deposited to a thickness of 0.1 μm. This film thickness may be such that it covers the gate oxide film 12. Next, the ozone concentration is increased to about 5%, and an ozone TEOS film (5%) 15 is deposited to 0.6 μm as shown in FIG. This film thickness is a thickness necessary for the interlayer insulating film.

In the interlayer insulating film thus formed, even if the ozone concentration of the ozone TEOS film is increased, the underlying gate oxide film 12 is completely covered with the ozone TEOS film (1%) 14. There is almost no influence of the film 12, and unevenness hardly appears on the surface of the ozone TEOS film (5%) 15. Further, the ozone TEOS film (5%) 15 has a good film quality with extremely good coverage and low hygroscopicity, because the deposition shape at the corners of the steps of the polysilicon film 13 is a flow shape.

[0005]

As described above, in the conventional semiconductor device, since the thermal oxide film is used as the base insulating film,
Ozone TEOS film with high ozone concentration (5
%) May cause surface roughness due to its pattern dependence. To prevent this, an ozone TEOS film with a low ozone concentration (1%) is applied, and an ozone TEOS film (5%) is deposited on it. Is formed. Therefore, a step of continuously forming an ozone TEOS film with different ozone concentrations is required, and there is a problem that the process work becomes complicated. When aluminum wiring is used for the wiring, the surface irregularity of the ozone TEOS film becomes remarkable due to the pattern dependence of the ozone TEOS film with high ozone concentration,
When applied to fine wiring, there is also a problem that voids are generated in the interlayer insulating film due to its coverage property. Furthermore, although an ozone TEOS film having a low ozone concentration is formed, since this kind of ozone TEOS film generally has a large amount of moisture in the film, it has a high hygroscopic property, and there is a problem as a film quality for securing insulation between wiring layers. is there.

Therefore, as shown in FIG. 5, a plasma theos film 16 is formed further under the ozone theos film (1%) 14 to form an interlayer insulating film having a three-layer structure. Attempts have also been made to prevent the deterioration of the film quality of the interlayer insulating film due to the amount of water, but this causes a problem that the interlayer insulating film is further multi-layered and the production thereof is further complicated. In particular, in FIG. 5, the ozone TEOS film (5
%), The surface is flattened by an etching back method using organic silica or the like, and the plasma theos film 17 is formed on the flattened surface. The number of layers is further increased, and the manufacturing process is further complicated. An object of the present invention is to provide a semiconductor device having an interlayer insulating film having an improved film quality as an interlayer insulating film and a manufacturing method thereof, while simplifying the formation process of the ozone TEOS film.

[0007]

The semiconductor device of the present invention comprises:
The underlying insulating film of the wiring is formed of a plasma oxide film by the silane plasma CVD method, and the interlayer insulating film covering the wiring is formed of an organic silane / ozone-based atmospheric pressure CVD method having a high ozone concentration. In this case, the base insulating film has a two-layer structure including a BPSG film and a plasma oxide film. Alternatively, the interlayer insulating film has a two-layer structure including an ozone TEOS film and a plasma TEOS film formed by an organic silane plasma CVD method. Further, the method of manufacturing a semiconductor device of the present invention comprises a step of forming a plasma oxide film by a silane plasma CVD method as a base insulating film on a silicon substrate, and a step of forming aluminum wiring of a required pattern on the base insulating film. And a step of forming an ozone TEOS film having a high ozone concentration by an organic silane / ozone-based atmospheric pressure CVD method as an interlayer insulating film on the entire surface including the aluminum wiring. In this case, a step of forming a BPSG film as a first base insulating film on the silicon substrate is provided, and after forming an ozone TEOS film, an organic silica film is applied thereon, and the organic silica film and the silicon oxide film are formed. The method may include a step of etching back to flatten the surface and a step of forming a plasma theos film on the flattened ozone theos film.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of an embodiment of the present invention. A BP having a thickness of about 0.5 μm is formed as a first base insulating film on the silicon substrate 1.
The SG film 2 is provided, and the plasma silicon oxide film 3 having a thickness of about 0.2 μm is provided thereon as a second base insulating film.
Then, on the second base insulating film 3, the wiring 4 having a required pattern formed of an aluminum film having a thickness of about 1 μm is provided. Then, an ozone TEOS film 5 having a thickness of 0.8 μm is deposited as an interlayer insulating film, and a plasma TEOS film 7 having a thickness of 0.5 μm is further provided on the flattened upper surface thereof.

FIG. 2 is a sectional view showing the structure of FIG. 1 in the order of manufacturing steps. First, as shown in FIG. 2A, BPSG of 0.5 is formed on the silicon substrate 1 by atmospheric pressure vapor deposition.
After depositing to a thickness of μm, heat treatment is performed in a nitrogen gas atmosphere at 900 ° C. for 30 minutes to form a first base insulating film (BPSG).
Film 2) is formed. Next, using a parallel plate type single wafer type plasma chemical vapor deposition apparatus on the first base insulating film 2,
Silane-based plasma silicon oxide film 3 as a base insulating film
(Hereinafter referred to as plasma oxide film) is formed to a thickness of 0.2 μm. Then, an aluminum film containing copper and silicon is deposited to a thickness of 1 μm on the plasma oxide film 3 by a sputtering method and patterned to form the wiring 4. Next, an ozone TEOS film 5 having a thickness of 0.8 μm is deposited on the surface including the wiring 4 using a parallel plate type single wafer type atmospheric pressure vapor deposition apparatus under the conditions of a substrate temperature of 400 ° C. and an ozone concentration of 5%.

Next, as shown in FIG. 2B, an organic silica film 6 is formed with a thickness of about 1 μm by a spin coating method. Then, as shown in FIG. 2C, a parallel plate type batch type reactive ion etching apparatus was used, and the CF4 gas flow rate was 100 SCCM, the O2 gas flow rate was 15 SCCM, the pressure was 0.1 torr, the frequency was 13.56 MHZ, and the high frequency power was 0. Under the condition of 3 W / cm ² , the entire surface of the organic silica film 6 and a part of the surface of the ozone TEOS film 5 are etched back to flatten the surface of the ozone TEOS film 5. Here, the etching rate of the ozone TEOS film 5 is made substantially the same as or slightly higher than the etching rate of the organic silica film 6. Finally, the flattened ozone TEOS film 5
The structure shown in FIG. 1 is completed by depositing the plasma TEOS film 7 with a thickness of 0.5 μm on the substrate using a parallel plate type single wafer type plasma chemical vapor deposition apparatus.

As described above, by using the plasma oxide film as the second base insulating film, the growth rate of the ozone TEOS film on the aluminum and the plasma oxide film is increased as shown in FIG. 3 on the silicon substrate. Since it is about the same as the above, it is possible to eliminate the pattern dependence of the ozone TEOS film due to aluminum and prevent the surface irregularities from becoming conspicuous. Therefore, the coverage of the ozone TEOS film is improved even with a structure in which the dimension between wirings is fine, and voids and the like are prevented from occurring between the wirings. For example, 0.25 between wiring
It is possible to apply μm to next-generation devices. Further, in this embodiment, since the surface is etched back by using the organic silica film, the flatness can be further promoted. Further, in this case, since the interlayer insulating film is formed only by the ozone TEOS film having a high ozone concentration (5%), it is not necessary to form the ozone TEOS film (1%) having a large amount of water content in the film as the first interlayer insulating film. Thus, it becomes possible to simplify the manufacturing process of the ozone TEOS film and improve the film quality of the interlayer insulating film.

Here, the underlying insulating film has a two-layer structure of a BPSG film and a plasma oxide film in the above embodiment,
If the underlying insulating film directly below the wiring is formed of a plasma oxide film, the insulating film below it may be formed of another insulating film. Further, in the above embodiment, the 5% ozone TEOS film is used as the interlayer insulating film, but the ozone concentration may be increased or decreased to some extent. Further, it is optional to form the plasma TEOS film on this ozone TEOS film (5%).

[0013]

As described above, according to the present invention, the base insulating film is formed of the silane-based plasma oxide film, and the interlayer insulating film is formed of only the ozone TEOS film having a high ozone concentration. Since the surface roughness of the ozone TEOS film and the pattern dependence of the growth rate can be suppressed without forming the ozone TEOS film and the ozone TEOS film of high ozone concentration, a more reliable interlayer insulating film is formed. be able to. Further, since only high ozone concentration is used, hygroscopicity is reduced and film quality is improved. Further, according to the method of the present invention, the step of forming the ozone TEOS film having a low ozone concentration is not necessary, so that there is an effect that the manufacturing process of the ozone TEOS film can be simplified.

[Brief description of drawings]

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

FIG. 2 is a cross-sectional view showing a method of manufacturing the semiconductor device of FIG. 1 in process order.

FIG. 3 is a characteristic diagram showing the relationship between the film formation time of an ozone TEOS film and its film thickness.

FIG. 4 is a cross-sectional view showing a method of manufacturing a conventional semiconductor device in the order of steps.

FIG. 5 is a cross-sectional view of another conventional semiconductor device.

[Explanation of symbols]

 1 Silicon Substrate 2 BPSG Film (First Underlayer Insulating Film) 3 Plasma Oxide Film (Second Underlayer Insulating Film) 4 Aluminum Wiring 5 Ozone Theos Film (5%) 6 Organic Silica Film 7 Plasma Theos Film

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[Procedure amendment]

[Submission date] September 22, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction content]

[0001]

The present invention relates to relates to a semiconductor device in which interlayer insulating film on the wiring formed over the base insulating film is formed, in particular to a structure and a manufacturing method thereof of the base insulating film and the interlayer insulating film.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction content]

[0002]

2. Description of the Related Art In a conventional semiconductor device having high integration, a wiring is formed on a base insulating film, and an interlayer insulating film is formed on the wiring to form an upper wiring. Has been adopted. As this interlayer insulating film, there is used atmospheric pressure chemical vapor deposition (CV) using ethyl silicate (Si (OC ₂ H ₅ ) ₄ : hereinafter referred to as TEOS) and ozone.
A silicon oxide film (hereinafter referred to as an ozone TEOS film) formed by using the method D) is used. In this ozone TEOS film, the underlying insulating film is polysilicon (polycrystalline silicon).
The film is excellent in flatness of the surface, but when the underlying insulating film is a thermal oxide film, unevenness may occur on the surface. Further, the higher the ozone concentration at the time of forming the ozone TEOS film, the larger the difference in the unevenness of the surface tends to be due to the influence of aluminum forming the underlying wiring. Therefore, stress is applied to the wiring formed on the uneven surface of the ozone TEOS film, and disconnection or the like is likely to occur, which may deteriorate reliability.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

Next, as shown in FIG. 2B, an organic silica film 6 is formed with a thickness of about 1 μm by a spin coating method. Then, as shown in FIG. 2 (c), a parallel plate type batch type reactive ion etching apparatus is used, CF ₄ gas flow rate 100 SCCM, O ₂ gas flow rate 15 SCCM, pressure 0.1 torr, frequency 13.56 MHZ, and high frequency power. Under the condition of 0.3 W / cm ² , the entire surface of the organic silica film 6 and a part of the surface of the ozone TEOS film 5 are etched back to flatten the surface of the ozone TEOS film 5. Here, the etching rate of the ozone TEOS film 5 is made substantially the same as or slightly higher than the etching rate of the organic silica film 6. Finally, the flattened ozone TEOS film 5
The structure shown in FIG. 1 is completed by depositing the plasma TEOS film 7 with a thickness of 0.5 μm on the substrate using a parallel plate type single wafer type plasma chemical vapor deposition apparatus.

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Claims (5)

[Claims] 1. A semiconductor device having a base insulating film on a substrate, wiring on the base insulating film, and an interlayer insulating film formed to cover the wiring, wherein the base insulating film is silane. 1. A semiconductor device, which is a plasma silicon oxide film formed by a system plasma CVD method, wherein the interlayer insulating film is a silicon oxide film formed by an organic silane / ozone system atmospheric pressure CVD method having a high ozone concentration. 2. The semiconductor device according to claim 1, wherein the base insulating film has a two-layer structure of a BPSG film and a plasma silicon oxide film formed by a silane plasma CVD method. 3. The semiconductor device according to claim 1, wherein the interlayer insulating film has a two-layer structure of a silicon oxide film formed by an organic silane / ozone-based atmospheric pressure CVD method and a silicon oxide film formed by an organic silane-based plasma CVD method. . 4. A step of forming a plasma silicon film by a silane plasma CVD method as a base insulating film on a silicon substrate, a step of forming an aluminum wiring of a required pattern on the base insulating film, and including the aluminum wiring. And a step of forming a silicon oxide film as an interlayer insulating film on the entire surface by an organic silane / ozone-based atmospheric pressure CVD method having a high ozone concentration. 5. A step of forming a BPSG film as a first base insulating film on a silicon substrate, a step of forming a plasma silicon film by a silane plasma CVD method as a second base insulating film thereon, and the base insulating film. A step of forming an aluminum wiring having a desired pattern on the film, a step of forming a silicon oxide film by an organic silane / ozone-based atmospheric pressure CVD method having a high ozone concentration as an interlayer insulating film on the entire surface including the aluminum wiring, and A step of applying an organic silica film on the surface of the silicon oxide film, and etching back the organic silica film and the silicon oxide film to planarize the surface; and an organosilane-based plasma C on the planarized silicon oxide film.
And a step of forming a silicon oxide film by the VD method.