JPH0645448A - Semiconductor device - Google Patents

Abstract

PURPOSE:To provide a semiconductor device in which fuses for redundant circuits can be blown by a low-energy laser beam and they are laminated on interconnections to realize large scale integration. CONSTITUTION:Thin, patterned metal films 3 and 4, including interconnection patterns, are formed on an insulating layer 6. A plated interconnection 1 is formed on part of the metal film, and the remaining part of the metal film forms fuses 2. Since the fuses are made of thin metal, they can be formed on the uppermost layer and thus blown by lower energy. In addition, this structure is suitable for high scale integration because the fuses can be laminated on interconnections.

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 a fuse that is blown by a laser beam.

[0002]

2. Description of the Related Art A memory portion of a semiconductor device has a plurality of identical circuits and has a very high element density, so that it is difficult to obtain a good product as compared with other circuit portions. Therefore, conventionally, a semiconductor device is manufactured in a state where a redundant circuit is arranged in advance, the condition of a memory portion is judged in an electric test thereafter, a defective portion is cut off, and a redundant circuit is connected instead. It is designed to be used as a non-defective product. A fuse is used to disconnect and connect the defective portion and the redundant circuit, and the fuse is blown by a laser beam to disconnect the circuit. When the fuse is blown by the laser beam, the heat conduction of the wiring is too high and a laser beam of very high energy is required. Therefore, the fuse is formed by using polysilicon under the wiring layer, and the fuse is cut by the laser beam. It is blown out.

[0003]

In such a conventional fuse, if the adhered film on the fuse is large, the laser light is attenuated by the time it reaches the fuse.
After the fuse is formed, etching is performed to selectively remove the adhered portion on the fuse. However, in recent semiconductor devices, the number of wiring layers tends to increase, the number of insulating films between wiring layers also increases, and the thickness also increases. In addition, an organic coating material is often used to reduce the step difference of the wiring, and even if the insulating film on the fuse is removed by etching during the manufacturing process, the organic material will not be dented when the organic material is applied later. However, there is a problem that the surface becomes flat and the thickness of the insulating film cannot be reduced.

As a countermeasure against this, it is conceivable to perform etching on the fuse after growing the entire insulating film.
Since the dents formed by etching become deeper, dirt and the like are likely to accumulate due to subsequent handling, resulting in a problem of poor reliability. Further, since the insulating film on the fuse is etched, the wiring cannot be arranged on the fuse, which makes it difficult to achieve high integration of the semiconductor device. An object of the present invention is to provide a semiconductor device capable of fusing a fuse with a low-energy laser beam and stacking a fuse and a wiring to achieve high integration.

[0005]

According to the present invention, a thin metal film formed in a desired pattern including a wiring pattern on a base insulating film, and a thin metal film formed in a region where a part of the thin metal film remains by plating. And a thin metal film on which the wiring is not formed is configured as a fuse.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. 1A and 1B show a first embodiment of the present invention. FIG. 1A is a plan layout diagram and FIG. 1B is a sectional view taken along the line AA. Titanium-tungsten 3 is formed on the base insulating film 6, and sputtered gold 4 formed by the sputtering method is formed on the titanium-tungsten 3. Furthermore, the wiring 1 formed by electrolytic plating or electroless plating is formed on this.
Then, the wiring 1 is cut at a part thereof, and the cut portion is composed of only the titanium tungsten 3 and the sputtered gold 4 to form the fuse 2. Then, a nitride film 5 is deposited as a passivation film on the fuse 2 and the wiring 1.

This manufacturing method will be described with reference to FIG. First, as shown in FIG. 2A, titanium-tungsten 3 is sputtered on the base insulating film 6 by 1000 Å, and gold 4 serving as a growth nucleus of plating is sputtered by 500 Å. After that, as shown in FIG. 2B, the photoresist 7 is patterned so as to cover portions other than the wiring portion, and electrolytic plating or electroless plating is performed to 1.2 μm.
Plating with the thickness of. Next, as shown in FIG. 2C, the sputtered gold 4 and the titanium tungsten 3 are etched while leaving the photoresist 7 only at the locations where the photoresist 7 is etched to form the fuse. At this time, the surface of the wiring 1 not covered with the photoresist 7 is etched by about 2000 Å, so that a protrusion of about 2000 Å is formed on the wiring at both ends of the fuse. Then, the photoresist 7 is removed, and a nitride film 1 μm is formed as a passivation film on the photoresist 7.
m.

According to this structure, the titanium tungsten 3
The fuse 2 can be composed of a very thin metal pattern composed of the sputtered gold 4 and the sputtered gold 4. The fuse formed in this way has lower thermal conductivity than ordinary wiring, and can be blown by a laser beam of the same energy as the conventional one. Therefore, it can be sufficiently used as a fuse for a redundant circuit.

FIG. 3 is a sectional view of a second embodiment of the present invention. Here, the sputtered gold in the fuse portion is eliminated.
In this structure, for example, after the step of FIG. 2B, the photoresist 7 is removed, the exposed sputtered gold 4 is removed by 500Å etching, and then the titanium tungsten 3 is etched as in the first embodiment. To form. By doing so, the metal thickness of the fuse portion can be made thinner than in the first embodiment, and the heat conduction can be further lowered.

After the step of FIG. 2A, the sputtered gold 4 and the titanium tungsten 3 were etched so as to remain only in the wiring portion and the fuse portion, the photoresist 7 was removed, and the photoresist was patterned again. The gold plating of the wiring part may be formed by electroless gold plating. In this case, in the first and second embodiments, since the photoresist is patterned only on the fuse portion after the wiring 1 is formed, the photoresist is spread over the 1.2 μm wiring step. Although it is difficult to increase the patterning accuracy because patterning is required, patterning accuracy can be improved by patterning on a flat surface in this embodiment.

[0011]

As described above, according to the present invention, since the fuse is formed by the thin metal film provided in the pattern region including the wiring layer, in the semiconductor device using the multilayer wiring, for example, the wiring of the uppermost layer is formed. A fuse can be formed in a layer, an insulating film does not need to be etched, the fuse can be blown with low energy, and wiring can be formed so as to overlap with the fuse. Enables integration.

[Brief description of drawings]

FIG. 1 is a plan view of a first embodiment of the present invention and a sectional view taken along line AA thereof.

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

FIG. 3 is a sectional view of a second embodiment of the present invention.

[Explanation of symbols]

 1 Wiring 2 Fuse 3 Titanium Tungsten 4 Sputtered Gold 5 Nitride Film 6 Base Insulation Film

Claims (1)

[Claims] 1. A thin metal film formed in a desired pattern including a wiring pattern on a base insulating film, and a wiring formed by a plating method in a region where a part of the thin metal film is left, A semiconductor device comprising a thin metal film having no wiring formed as a fuse.