JPH08236531A - Wiring forming method for semiconductor device - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention is designed to prevent hilllock from occurring on a wiring pattern when sintering the wiring pattern.
An object of the present invention is to provide a wiring forming method for a semiconductor device. A metal layer 12 is first formed on a semiconductor substrate 11 having an oxide film formed on its surface, a resist pattern 14 for an etching mask is formed on the metal layer 12, and then a metal layer other than the wiring portion is formed by etching. After removing the resist, the resist is removed to form a wiring pattern 12a made of a metal layer, and finally, a protective film or an interlayer insulating film 15 is formed on the entire substrate surface.
In the method of forming a wiring of the semiconductor device 10, the thin film 1 made of the same material as the protective film or the interlayer insulating film is formed on the metal layer before forming the resist pattern.
3 is formed, the thin film is patterned by etching, and then the metal layer 12 is etched using the thin film 13a as an etching mask.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring forming method for a semiconductor device for forming a wiring pattern of a metal layer on the surface of the semiconductor device via an oxide film.

[0002]

2. Description of the Related Art Conventionally, a wiring pattern made of a metal layer on the surface of a semiconductor device is formed as shown in FIG. That is, in the semiconductor device 1, an oxide film (not shown) is formed on the surface of a semiconductor substrate, for example, a silicon substrate 2. For such a semiconductor device 1, as shown in FIG.
As shown in (A), first, a metal layer 3 made of a metal, for example, aluminum, is formed over the entire surface of the silicon substrate 2.
To form.

Then, as shown in FIG. 2B, a resist pattern 4 for an etching mask is formed on the metal layer 3.

Thereafter, as shown in FIG. 2C, the metal layer 3 is subjected to, for example, wet etching.
Among them, the metal layer 3 which is not covered with the resist pattern 4 except the wiring portion is removed to form the wiring pattern 3a.

Subsequently, as shown in FIG. 2D, the resist pattern 4 is removed by an appropriate method, and the wiring pattern 3a is further eutectic-bonded to the electrode portion by heating, so-called sintering. Is performed.

Finally, as shown in FIG. 2E, a protective film or an interlayer insulating film 5 is formed over the entire surface of the semiconductor device 1.
The semiconductor device 1 is completed by forming the.

[0007]

However, in the semiconductor device 1 having such a structure, when the wiring pattern 3a in FIG. 2D is sintered, the surface of the wiring pattern 3a is heated by heating the wiring pattern 3a. As shown in (A), so-called hill rock 6 may grow. this is,
It is considered that the strain of the metal crystal forming the metal layer 3 is the cause. Then, when the protective film or the interlayer insulating film 5 is directly formed on the wiring pattern 3a with the hilllock 6 grown, as shown in FIG. 3B, the protective film is formed on the hilllock 6. Alternatively, the interlayer insulating film 5 is formed, and in some cases, at the hilllock 6 portion,
The protective film or the interlayer insulating film 5 may be thinned or cut. Therefore, there is a problem that pinholes, cracks and the like are generated in the area of the hilllock 6 of the protective film or the interlayer insulating film 5, and the coverage with the protective film or the interlayer insulating film 5 is deteriorated. .

In view of the above points, an object of the present invention is to provide a wiring forming method for a semiconductor device in which hilllock does not occur on the wiring pattern when the wiring pattern is sintered.

[0009]

According to the present invention, a metal layer is first formed on a semiconductor substrate having an oxide film formed on the surface thereof, and a resist pattern for an etching mask is formed on the metal layer. After forming, subsequently removing the metal layer other than the wiring portion by etching, the resist is removed to form a wiring pattern by the metal layer, and finally a protective film or an interlayer insulating film is formed on the entire substrate surface. In the wiring forming method for a semiconductor device, before forming the resist pattern, a thin film made of the same material as the protective film or the interlayer insulating film is formed on the metal layer, and the thin film is patterned by etching, and then the thin film is formed. This is achieved by a method for forming a wiring of a semiconductor device, characterized in that the metal layer is etched by using as an etching mask.

In the method for forming a wiring of a semiconductor device according to the present invention, the resist pattern is preferably removed after etching the thin film.

In the method for forming a wiring of a semiconductor device according to the present invention, the resist pattern is preferably removed after etching the metal layer.

[0012]

According to the above structure, when the metal layer is etched, not the resist pattern but the thin film made of the same material as the protective film or the interlayer insulating film is used as the etching mask. Since the etching resistance is better than that of the pattern, an accurate wiring pattern can be formed.

Further, after sintering the metal layer, at the time of sintering, since the thin film remains on the upper surface of the wiring pattern, hillocks may grow on the upper surface of the wiring pattern by heating. There is no. Therefore,
After that, when the protective film or the interlayer insulating film is formed on the wiring pattern, the protective film or the interlayer insulating film will not be thinned or cut due to hilllock, so that there is no pinhole, crack, etc. Alternatively, the coverage of the interlayer insulating film can be improved.

Since the above-mentioned thin film is made of the same material as the protective film or the interlayer insulating film, it becomes the same as the protective film or the interlayer insulating film when the protective film or the interlayer insulating film is formed. Thus, the wiring pattern of the semiconductor device having the same structure as the conventional one can be formed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on the embodiments shown in the drawings. FIG. 1 sequentially shows manufacturing steps in an embodiment of a method for forming wiring of a semiconductor device according to the present invention.

In FIG. 1, a semiconductor device 10 has an oxide film (not shown) formed on the surface of a semiconductor substrate such as a silicon substrate 11. Then, as shown in FIG. 1A, a metal layer 12 made of a metal such as aluminum is first formed on the entire surface of the silicon substrate 11 in the semiconductor device 10.

Here, as shown in FIG. 1B, a thin film 13 made of the same material as a protective film or an interlayer insulating film described later is formed on the metal layer 12. This thin film 13 is made of, for example, NSG (non-doped silicate glass), PSG.
(Phosphorus silicate glass) or SiN (silicon nitride) or the like.

Then, as shown in FIG. 1C, a resist pattern 1 for an etching mask is formed on the thin film 13.
4 is formed.

Thereafter, as shown in FIG. 1D, wet etching, for example, is used to remove the portion of the thin film 13 not covered with the resist pattern 14 using the resist pattern 14 as an etching mask. .

Subsequently, as shown in FIG. 1E, the resist pattern 14 is removed by an appropriate method.

Thereafter, as shown in FIG. 1F, the metal layer 12 of the metal layer 12 other than the wiring portion not covered by the thin film 13 is removed by using the pattern 13a of the thin film 13 as an etching mask. The wiring pattern 12a is formed. Further, by heating, the wiring pattern 12
So-called sintering is performed in which a is eutectic-bonded to the electrode portion.

Finally, as shown in FIG. 1G, the semiconductor device 10 is completed by forming a protective film or an interlayer insulating film 15 over the entire surface of the semiconductor device 10.

The semiconductor device wiring forming method according to the embodiment of the present invention is configured as described above.
In, the upper portion of the metal layer 12 is dry-etched using the pattern 13 a of the thin film 13 as an etching mask. As a result, the thin film 13 has better etching resistance than the resist pattern 14,
The wiring pattern 12a of the metal layer 12 can be formed more accurately.

When the wiring pattern 12a of the metal layer 12 is sintered, the upper surface of the wiring pattern 12a is
Since the thin film 13 is covered with the pattern 13a, the hillock does not grow even if the metal crystal forming the wiring pattern 12a is distorted. Therefore, when the protective film or the interlayer insulating film 15 is formed thereafter, the protective film or the interlayer insulating film 15 does not become thin or cut due to the presence of hillocks. Therefore, the coating property of can be improved.

In the above embodiment, the resist pattern 14 is removed after the thin film 13 is etched, but the present invention is not limited to this.
Obviously, it may be removed before sintering the wiring pattern of the metal film.

[0026]

As described above, according to the present invention, when etching a metal layer, not a resist pattern but a thin film made of the same material as a protective film or an interlayer insulating film is used as an etching mask. As a result, since the thin film has better etching resistance than the resist pattern, an accurate wiring pattern can be formed.

Further, after sintering the metal layer, at the time of sintering, since the thin film remains on the upper surface of the wiring pattern, hillocks may grow on the upper surface of the wiring pattern due to the heating. There is no. Therefore,
After that, when the protective film or the interlayer insulating film is formed on the wiring pattern, the protective film or the interlayer insulating film will not be thinned or cut due to hilllock, so that there is no pinhole, crack, etc. Alternatively, the coverage of the interlayer insulating film can be improved.

Thus, according to the present invention, it is possible to provide an extremely excellent method for forming a wiring of a semiconductor device in which hilllock is prevented from occurring on the wiring pattern when the wiring pattern is sintered.

[Brief description of drawings]

1A to 1G are schematic cross-sectional views sequentially showing manufacturing steps in an example of a method for forming wiring of a semiconductor device according to the present invention.

2A to 2E are sequential cross-sectional views showing manufacturing steps in an example of a conventional method for forming a wiring of a semiconductor device, and FIGS.

3A is a schematic cross-sectional view showing the influence of a protective film or an interlayer insulating film in the manufacturing process of FIG.

[Explanation of symbols]

 10 semiconductor device 11 semiconductor substrate 12 metal layer 12a wiring pattern 13 thin film 13a thin film pattern 14 resist pattern 15 protective film or interlayer insulating film

Claims (3)

[Claims] 1. A metal layer is first formed on a semiconductor substrate having an oxide film formed on its surface, a resist pattern for an etching mask is formed on the metal layer, and then a metal layer other than the wiring portion is formed by etching. After removing the resist, the resist is removed to form a wiring pattern of a metal layer, and finally a protective film or an interlayer insulating film is formed on the entire substrate surface. Then, a thin film made of the same material as the protective film or the interlayer insulating film is formed on the metal layer, the thin film is patterned by etching, and then the metal layer is etched using the thin film as an etching mask. A method for forming a wiring of a semiconductor device, comprising: 2. The method for forming a wiring of a semiconductor device according to claim 1, wherein the resist pattern is removed after etching the thin film. 3. The wiring forming method for a semiconductor device according to claim 1, wherein the resist pattern is removed after etching the metal layer.