JP3079608B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of forming a metal wiring of a semiconductor device.

[0002]

2. Description of the Related Art A conventional method for forming a metal wiring will be described with reference to FIGS.

[0005] First, as shown in FIG. 2A, an insulating film 2 made of a silicon oxide film is grown on a semiconductor substrate 1 having undergone a diffusion step.

Next, as shown in FIG. 2B, a resist 4 is applied and patterned. At this time, a defect opening 6 may be formed simultaneously with the regular contact opening 5 due to dust on the semiconductor substrate 1 or a mask defect in the patterning step.

[0005] Next, as shown in FIG.
Is selectively etched, and then the resist 4 is removed.

Next, as shown in FIG. 2D, a metal film 3 made of aluminum or the like is deposited.

Next, as shown in FIG. 2E, an opening 10 is formed by applying a resist 7 again and then patterning.

Next, as shown in FIG.
Is selectively etched, and then the resist 7 is removed to complete a metal wiring made of the metal film 3.

[0009]

In the conventional method for forming a metal wiring, the defect opening 6 shown in FIG.
As a result, an opening is also formed in the insulating film 2. There is a problem in that a short-circuit portion with the metal wiring is formed, and when the opening is large, an initial failure occurs.

As a countermeasure against short-circuit failure, there is a method in which lithography is repeated twice using two layers of insulating films made of different materials. At this time, the insulating film is abnormally thick, and the step in the contact opening becomes large. As a result, the step coverage of the wiring metal is degraded, which causes open failure due to disconnection.

[0011]

According to a method of manufacturing a semiconductor device of the present invention, a step of forming an insulating film on one main surface of a semiconductor substrate and then depositing a first metal film, and a step of depositing a first resist. Selectively etching the first metal film as a mask to form a first opening; and removing the first resist and then selectively etching the insulating film using a second resist as a mask. Forming a second opening inside the first opening, removing the second resist, depositing a second metal film on the entire surface, and then using the third resist as a mask to form the second metal Selectively etching the film and the first metal film.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG.

First, as shown in FIG. 1A, after an insulating film 2 made of a silicon oxide film is grown on a semiconductor substrate 1 in which a diffusion process has been completed, a first metal film 3 is deposited. After that, a resist 4 is applied and then patterned.
At this time, in addition to the regular contact opening 5, the defect opening 6
May be formed.

Next, as shown in FIG. 1B, the first metal film 3 is formed using a phosphoric acid-based solution with the resist 4 as a mask.
Is selectively etched (the silicon oxide film is not etched). Next, the resist 4 is removed.

At this time, the contact opening 5 is made larger than the final contact.

Next, as shown in FIG. 1C, a resist 7 is applied and then patterned to form a contact opening 8.

Next, as shown in FIG. 1D, the insulating film 2 is selectively etched using a resist 7 as a mask and a hydrofluoric acid-based solution. At this time, even if the resist 7 has a defect opening, the first metal film 3 is slightly etched because the etching rate is low, but the insulating film 2 is not etched.

Next, as shown in FIG. 1E, a second metal film 9 is deposited on the entire surface. At this time, the insulating film 2 below the defect opening 6 is intact and has been repaired by the second metal film 9.

Next, as shown in FIG. 1F, the second metal film 9 and the first metal film 9 are formed using a resist (not shown) as a mask.
Is selectively etched to complete a metal wiring composed of the first metal film 3 and the second metal film 9.

[0020]

By using the two-layer metal film of the present invention, almost 100% of short-circuit defects due to defect openings caused by dust or mask defects could be eliminated.

Further, since it is not necessary to make the insulating film abnormally thick, there is no fear of open failure due to insufficient step coverage.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention in the order of steps.

FIG. 2 is a cross-sectional view showing a method of forming a metal wiring according to a conventional technique in the order of steps.

[Explanation of symbols]

 Reference Signs List 1 semiconductor substrate 2 insulating film 3 first metal film 4 resist 5 contact opening 6 defect opening 7 resist 8 constant opening 9 second metal film 10 opening of metal film

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Claims (1)

(57) [Claims] Forming an insulating film on one main surface of a semiconductor substrate, depositing a first metal film, and selectively etching the first metal film using a first resist as a mask; Forming a first opening; and forming a second opening inside the first opening by removing the first resist and then selectively etching the insulating film using the second resist as a mask. Removing the second resist, depositing a second metal film on the entire surface, and then selectively etching the second metal film and the first metal film using the third resist as a mask; A method for manufacturing a semiconductor device including: