JP2003007708A - Semiconductor device and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reliable semiconductor device that prevents the whisker- like protrusions of an upper layer film due to side etching of a lower layer film when the surface electrode wiring of a semiconductor device is to be formed, and to provide a method for manufacturing the reliable semiconductor device. SOLUTION: In surface electrode wiring that is formed on a semiconductor substrate, and has a conductive film with at least two layers, one portion of a lower layer is exposed from a terminal section of the uppermost layer of the conductive film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly to a semiconductor device having improved reliability in surface electrode wiring and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, the surface electrode wiring of a semiconductor device has been formed as follows. That is, as shown in FIG. 2A, a device region (not shown), a surface oxide film 2 and a contact hole 3 are formed on a Si substrate 1, and a Ni film is formed on the device region.
The film 4 is sequentially formed to have a thickness of 500 nm, and the Au film 5 is sequentially formed to have a thickness of 50 nm.
Then, as shown in FIG. 2B, a normal PEP (ph
The resist 6 is applied by photo-etching process patterning, exposure and development are performed using a predetermined mask, the upper Au film 5 is etched with a 15% ferric chloride aqueous solution, and then the lower Ni film 4 is continuously formed. Is etched with an aqueous solution of 2.9% iodine + 10.8% potassium iodide to form a surface electrode wiring consisting of two layers of Ni / Au.

However, in the surface electrode wiring thus formed, the Ni film has a large film thickness of 500 nm, and the wall surface is largely etched by such isotropic etching, and as shown in FIG. There occurs a phenomenon in which the end portion of the Au film patterned as described above floats up like a square. Then, as shown in FIG.
The pitted Au film is broken at the interface with Ni and bulges out to the surface like a whiskers, and contacts with other electrodes to cause a short circuit defect. Further, the beard-shaped Au film comes into contact with or separates from each other, and thus there is a problem that it is difficult to reliably detect a short circuit defect.

[0004]

As described above, conventionally, when the surface electrode wiring of the semiconductor device is formed, since the lower layer film is side-etched, the upper layer film bulges out like a beard and the reliability of the semiconductor device is deteriorated. There was a problem of doing.

Therefore, an object of the present invention is to provide a semiconductor device having high reliability and a method of manufacturing the semiconductor device by eliminating the drawbacks in the surface electrode wiring of the conventional semiconductor device.

[0006]

The semiconductor device of the present invention comprises:
A surface electrode wiring formed on a semiconductor substrate, wherein the surface electrode wiring has a conductive film of at least two layers, characterized in that a part of the lower layer is exposed from the terminal end of the uppermost layer. It is a thing.

A method of manufacturing a semiconductor device according to the present invention is
A step of sequentially forming first and second conductive films on a semiconductor substrate; a step of patterning the second conductive film into a first shape; and a part of the first conductive film. And forming a surface electrode wiring by patterning into a second shape exposed from the end portion of the first shape.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.
This will be described with reference to FIG.

As shown in FIG. 1A, a device region (not shown), a surface oxide film 2 and a contact hole 3 are formed on a Si substrate 1, and a Ni film which is a first conductive film is formed thereon. The film 4 has a thickness of 500 nm, and the Au film 5 as the second conductive film has a thickness of 50 nm.
nm, sputtering, or other known film forming method, and then the resist 6 is applied using normal PEP patterning.
The Au film is patterned into a shape as shown in FIG. 1B by exposing and developing using a photomask on which the first pattern is formed and etching using a 15% ferric chloride aqueous solution.

Then, as shown in FIG.
A resist 6'is applied on the film and the patterned Au film 5 ', exposed and developed using a photomask having a second pattern formed thereon, and iodine 2.9% + potassium iodide 10.
Etch with 8% aqueous solution. At this time, a second photomask having a remaining dimension d = 15 μm is used, and as shown in FIG. 1D, the Ni film 4 ′ is removed from the end portion of the previously patterned Au film 5 ′. Patterned to be exposed. At this time, the Ni film is side-etched as in the conventional case, but the etching does not proceed to the position immediately below the Au film, and d ′ = 5-1 from the Au film end portion.
The exposed state is 0 μm.

When a visual inspection was conducted on the semiconductor device having the surface electrode wiring formed in this manner, the defects, which had been 8% so far, were significantly reduced to 2%.

In this embodiment, Ni / Au is used as the electrode wiring material, but the material is not limited to these materials, and various alloys may be used. Further, a barrier metal layer such as V may be provided below these layers. Further, the present invention is not limited to two layers, and an effect can be obtained if the lower layer is a multilayer wiring thicker than the upper layer.

Although the remaining dimension is set to 15 μm in this embodiment, it is sufficient that the exposed portion of the layer below the terminal end of the uppermost layer remains after the side etching.

[0014]

According to the present invention, in forming a surface electrode wiring of a semiconductor device, a highly reliable semiconductor device in which the lower layer film is not side-etched and the upper layer film has a whisker-like protrusion, and a method of manufacturing the same. Can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing a manufacturing process of surface electrode wiring of a semiconductor device of the present invention.

FIG. 2 is a diagram showing a manufacturing process of a surface electrode wiring of a conventional semiconductor device.

FIG. 3 is a diagram showing a problem of a surface electrode wiring of a conventional semiconductor device.

[Explanation of symbols]

1 Si substrate 2 Surface oxide film 3 contact holes 4,4 'Ni film 5,5 'Au film 6,6 'resist

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Claims (2)

[Claims] 1. A surface electrode wiring formed on a semiconductor substrate, wherein the surface electrode wiring has at least two or more conductive films, and a part of the lower layer is exposed from the end portion of the uppermost layer. A semiconductor device characterized by the above. 2. A step of sequentially forming first and second conductive films on a semiconductor substrate, a step of patterning the second conductive film into a first shape, and a step of forming the first conductive film. And forming a surface electrode wiring by patterning a second shape, a part of which is exposed from the end portion of the first shape.