JP2782801B2 - Wiring structure of semiconductor device - Google Patents

Description

The present invention relates to a semiconductor device, and more particularly to a wiring structure using an organic insulating film as an interlayer insulating film.

[Conventional technology]

With the recent increase in the density of semiconductor devices, there has been an increasing demand for flattening an interlayer insulating film for insulating upper and lower wirings. Conventionally, an inorganic film has been used exclusively as an interlayer insulating film. However, in order to meet the above-mentioned requirement for flattening, the use of an organic insulating film has recently been proposed.

For example, FIG. 5 shows an example of this, in which a first organic insulating film 41 is formed as an interlayer insulating film, a conductive film 42 as a wiring is formed thereon, and a second organic insulating film 42 is formed thereon as a cover insulating film. A film 43 is formed.

FIG. 6 shows another example, in which a conductive film 52 is formed on a first organic insulating film 51, and the entire surface is covered with a thin inorganic insulating film 53, and then a second organic insulating film 54 is applied. I have. Here, a two-layer film of the inorganic insulating film 53 and the second organic insulating film 54 is a cover insulating film.

[Problems to be solved by the invention]

In the wiring structure shown in FIG. 5, since the conductive film 42 is directly covered with the second organic insulating film 43, the adhesion between the conductive film 42 and the second organic insulating film 43 is not sufficient. Therefore, there is a problem that the second organic insulating film 43 is easily peeled off, the function as a cover is reduced, and the reliability of the semiconductor device is reduced.

Further, in the wiring structure shown in FIG.
Since the inorganic insulating film 53 exists between the organic insulating films 54,
The adhesion between the conductive film 52 and the second organic insulating film 54 is sufficient. However, since the inorganic insulating film 53 exists between the first organic insulating film 51 and the second organic insulating film 52, the gas generated in the first organic insulating film 51 during the heat treatment at a high temperature becomes an inorganic insulating film. film
I was blocked by 53 and could not escape to the outside,
There is a problem that the adhesion between the first organic insulating film 51 and the inorganic insulating film 53 is deteriorated, and the cover insulating film is peeled off.

An object of the present invention is to solve such a problem, improve the adhesion between the wiring and the insulating film formed thereon, and improve the wiring structure between the insulating films formed above and below the wiring. To provide.

[Means for solving the problem]

The wiring structure of the present invention has a conductive film forming a wiring on a first organic insulating film forming an interlayer insulating film, and has an inorganic insulating film in contact only with a side surface of the conductive film. A second organic insulating film that covers the inorganic insulating film and is in contact with the first organic insulating film.

[Action]

In this configuration, the adhesion between the conductive film and the second organic insulating film is improved by the inorganic film provided on a part of the surface of the conductive film. Further, the first organic insulating film and the second organic insulating film are in direct contact with each other in a region other than the conductive film to improve the adhesion between them.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing a basic structure of the present invention, in which a conductive film 2 as a wiring is formed on a first organic insulating film 1 as an interlayer insulating film. An inorganic insulating film 3 is formed on the conductive film 2 so as to cover the upper surface and side surfaces thereof, and a second organic insulating film 4 is formed on the entire surface.

According to this configuration, since the inorganic insulating film 3 is interposed between the conductive film 2 and the second organic insulating film 4, the adhesion between the two can be improved. On the other hand, the first organic insulating film 1 and the second organic insulating film 1
Since the region other than the conductive film 2 is in direct contact with the organic insulating film 4, the gas generated during the heat treatment can be quickly released, and the adhesion between the two can be improved. This prevents peeling of the second organic insulating film 4 as a cover film, and improves the reliability of the semiconductor device.

2 (a) to 2 (e) are cross-sectional views showing a first embodiment of the wiring structure shown in FIG. 1 in the order of the manufacturing steps.

First, as shown in FIG. 2 (a), a tungsten film 12 is formed on a polyimide film 11 as a first organic insulating film constituting an interlayer insulating film by a magnetron sputtering method for about 2000.degree. A conductive film having a two-layer structure is formed to a thickness of 1 μm. Further, a silicon nitride film 14 as an inorganic insulating film is formed thereon by about 2000 約 by a plasma CVD method.

Next, as shown in FIG. 2 (b), the silicon nitride film 14, the gold film 13 and the tungsten film 12 are patterned by ordinary photolithography to form wiring.

Next, as shown in FIG. 2 (c), a silicon nitride film 15, which is an inorganic insulating film, is formed on the entire surface by plasma CVD at a thickness of about 1000.

Then, as shown in FIG. 2 (d), the silicon nitride film 15 is subjected to anisotropic dry etching. As a result, the silicon nitride film 14 is left on the upper surface of the wiring, and the silicon nitride film 15 is left on the side surface.
The surface of the wiring is covered with 14,15.

Then, as shown in FIG. 2E, a polyimide film 16 as a second organic insulating film as a cover film is formed on the entire surface by spin-on coating.

The structure of the wiring portion obtained in this manner has good adhesion between the gold film 13 and the silicon nitride film 14 and the gold film 13 and the silicon nitride film 15 that constitute the wiring, and the silicon nitride film 14 Also, the adhesion between the polyimide film 16 and the silicon nitride film 15 and the polyimide film 16 is good, so that the structure is very excellent in the adhesion between the wiring and the cover film.

Moreover, since the polyimide film 11 and the polyimide film 16 are in direct contact with each other, the polyimide film 11 is not heat-treated at a high temperature.
Since the gas generated inside escapes through the polyimide film 16, the adhesion between the polyimide film 11 and the polyimide film 16 does not deteriorate. That is, the structure is such that the adhesion between the interlayer insulating film and the cover insulating film is not deteriorated by the high-temperature heat treatment. Further, since the tungsten film 12 exists between the gold film 13 and the polyimide film 11, the structure has excellent adhesion between the wiring and the interlayer insulating film.

3 (a) to 3 (c) are sectional views showing a second embodiment of the present invention in the order of manufacturing steps.

First, as shown in FIG. 3 (a), an aluminum film 22 is formed to a thickness of about 0.5 μm by a magnetron sputtering method on an organic siloxane polymer film 21 constituting an interlayer insulating film, and then an inorganic insulating film silicon is formed by a plasma CVD method. Oxide film 23
Form about 2000 mm.

Next, as shown in FIG. 3 (b), the silicon oxide film 23 and the aluminum film 22 are patterned by a usual photolithography method to form wiring.

Thereafter, as shown in FIG. 3C, a polyimide film 24 is formed as a cover film by a spin-on coating method.

The wiring structure thus obtained has an aluminum film
Since the silicon oxide film 23, which is an inorganic insulating film, is present on the upper surface of the substrate 22, the structure has excellent adhesion between the upper surface of the wiring and the cover film. Moreover, since the organic siloxane polymer film 21 and the polyimide film 24 are in direct contact with each other, the gas generated in the organic siloxane polymer film 21 when heat treatment is performed at a high temperature escapes through the polyimide film 24. Adhesion with the polyimide film 24 does not deteriorate. That is, the adhesion between the interlayer insulating film and the cover insulating film is not deteriorated by the high-temperature heat treatment.

4 (a) to 4 (e) are cross-sectional views showing a third embodiment of the present invention in the order of manufacturing steps.

First, as shown in FIG. 4A, a titanium-tungsten alloy film 32 is formed on a polyimide film 31 constituting an interlayer insulating film by a magnetron sputtering method at a thickness of about 1000 °, and a gold film 33 is formed at a thickness of about 0.5 μm.

Next, as shown in FIG. 4B, the gold film 33 and the titanium-tungsten alloy film 32 are patterned by a normal photolithography method to form a wiring.

Next, as shown in FIG. 4C, an enzyme-containing silicon nitride film 34, which is an inorganic insulating film, is entirely formed by a plasma CVD method.
Form about 2000 mm.

Then, as shown in FIG. 4D, anisotropic etching is performed on the oxygen-containing silicon nitride film 34 to remove the oxygen-containing silicon nitride film 34 present on the upper surfaces of the polyimide film 31 and the gold film 33. I do. At this time, the side surfaces of the gold film 33 are covered with the oxygen-containing silicon nitride film 34.

Thereafter, as shown in FIG. 4E, a polyimide film 35 is formed as a cover insulating film by a spin-on coating method.

The structure of the wiring portion obtained in this manner is such that since the oxygen-containing silicon nitride film 34 as an inorganic insulating film exists on the side surface of the gold film 33 constituting the wiring, the adhesiveness between the wiring side surface portion and the cover insulating film is high. It has an excellent structure. Moreover, since the polyimide film 31 and the polyimide film 35 are in direct contact, the gas generated in the polyimide film 31 when heat treatment is performed at a high temperature escapes through the polyimide film 35, so that the polyimide film 31
There is no deterioration in the adhesion between the film and the polyimide film 35. That is, the adhesion between the interlayer insulating film and the cover insulating film is not deteriorated by the high-temperature heat treatment. Besides, gold film 33
Since the titanium tungsten alloy film 32 exists between the wiring and the polyimide film 31, the structure has excellent adhesion between the wiring and the lower interlayer insulating film.

In each of the above embodiments, the first organic insulating film and the second organic insulating film are in contact with each other in all the regions where the conductive film is not present. However, the adhesion between the two organic insulating films is not lost.

〔The invention's effect〕

As described above, according to the present invention, among the first to third embodiments with respect to the basic structure of the present invention, in the third embodiment in which the inorganic insulating film does not exist on the upper surface, a hole for wiring conduction is formed on the conductive film. When the opening is formed, only the second organic insulating film needs to be etched, which is more advantageous than the other embodiments in the manufacturing process. Therefore, the configuration of the third embodiment is adopted and the first organic insulating film is formed on the first organic insulating film. Since the second organic insulating film is formed after forming the inorganic insulating film only on the side surface of the provided conductive film, the adhesion between the conductive film and the second organic insulating film is improved by the inorganic film, and The direct contact between the first organic insulating film and the second organic insulating film improves the adhesion between them, and as a result, a wiring structure having excellent adhesion can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing the basic structure of the present invention, and FIG.
3 (a) to 3 (e) are cross-sectional views showing the first embodiment of the present invention in the order of the manufacturing steps, FIGS. 3 (a) to 3 (c) are cross-sectional views showing the second embodiment of the present invention in the order of the manufacturing steps, and FIG. FIGS. 5A and 5E are cross-sectional views showing a third embodiment of the present invention in the order of manufacturing steps, and FIGS. 5 and 6 are cross-sectional views showing different conventional wiring structures. 1 ... first organic insulating film, 2 ... conductive film, 3 ... inorganic insulating film, 4 ... second organic insulating film, 11 ... polyimide film, 12 ...
... tungsten film, 13 ... gold film, 14 ... silicon nitride film, 15 ... silicon nitride film, 16 ... polyimide film, 21 ...
... organic siloxane polymer film, 22 ... aluminum film,
23 ... silicon oxide film, 24 ... polyimide film, 31 ... polyimide film, 32 ... titanium-tungsten alloy film, 33 ...
Gold film, 34 oxygen-containing silicon nitride film, 35 polyimide film, 41 first organic insulating film, 42 conductive film, 43 second organic insulating film, 51 first organic insulating film , 52 ... conductive film,
53 ... inorganic insulating film, 54 ... second organic insulating film.

Claims (1)

(57) [Claims] A conductive film forming a wiring on a first organic insulating film forming an interlayer insulating film; an inorganic insulating film in contact with only a side surface of the conductive film; A wiring structure for a semiconductor device, comprising: a second organic insulating film that covers a film and is in contact with the first organic insulating film.