JP2002093910A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate residue of fuse member when the fuse member is cut off. SOLUTION: An Al fuse 1 which can be cut off by a laser light 4 is formed on an Si substrate 3. A dummy layer 5 for eliminating residue when the Al fuse 1 is cut off is arranged in a lower layer of the Al fuse 1.

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 structure for removing a residue when a fuse is blown.

[0002]

2. Description of the Related Art With the miniaturization, large capacity, and high speed of devices, in order to secure a yield, a defective bit in a memory cell and a spare memory cell prepared in a chip in advance are required. Replacement rescue techniques are important. As a switching method, a laser trimming method of programming by using a wiring layer as a fuse and cutting the fuse with a laser beam is widely used.

FIG. 5 is a sectional view showing a conventional semiconductor device. In the figure, reference numeral 11 denotes an Al fuse;
11b is a barrier metal, 12a to 12c are insulating films, 13
Is a Si substrate, and 14 is a laser beam.

[0004]

The conventional semiconductor device is configured as described above. In the case of metal wiring such as Al and Cu, TiN and TaN are formed under Al and Cu in order to improve the reliability of the wiring. And the like. Therefore, when the fuse is cut by the laser, the barrier metal film under the metal layer remains as a residue,
There has been a problem that the yield cannot be reduced without replacement.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to provide a semiconductor device which can prevent the generation of minute leaks and can omit a step of etching a residue. And

[0006]

According to a first aspect of the present invention, there is provided a semiconductor device comprising: an insulating film formed on a substrate;
A fuse is formed in an insulating film, and a dummy layer for removing a residue of the fuse at the time of cutting is provided below the fuse.

According to a second aspect of the present invention, there is provided a semiconductor device comprising:
The aluminum wiring below the fuse is used as a dummy layer.

According to a third aspect of the present invention, there is provided a semiconductor device comprising:
An electrical insulator is used as a dummy layer.

According to a fourth aspect of the present invention, there is provided a semiconductor device comprising:
The width of the dummy layer is larger than the width of the fuse.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing a fuse portion of a semiconductor device according to a first embodiment of the present invention, and FIG. 2 is a sectional view taken along line AA of FIG. In the drawing, 1 is an Al fuse, 1a is Al, 1b is a barrier metal, 2a to 2c are insulating films made of a silicon nitride film or a silicon oxide film, 3 is a Si substrate, 4 is a laser beam, 5
Is a dummy layer.

The Al fuse 1 is formed on a silicon substrate 3 above an insulating film 2 made of a silicon nitride film or a silicon oxide film. In general, a wiring layer lower than the uppermost wiring layer is often used as a fuse layer.
Is formed. Then, the Al fuse 1 is cut by irradiating the laser beam 4 from above.

Under the Al fuse 1, there is a barrier metal film 1b, which is made of TiN
The melting point of these materials is the upper Al
Because it is high compared to, it easily remains as a residue. And
When the fuse is cut by laser irradiation, there is a problem that a leak is generated due to the residue and replacement with a spare cell fails.

In the present invention, as shown in the figure, by disposing a dummy layer 5 below the Al fuse 1 and exploding the dummy layer 5, residues at the time of fuse cutting of the barrier metal layer 1b can be removed. FIG. 3 is a diagram showing a state after the dummy layer 5 has been exploded. In this embodiment, an Al fuse is used as a fuse material, but the present invention can be applied to a metal fuse material such as a copper wiring.

Further, in the present embodiment, the dummy layer 5
Although the Al wiring layer further below the Al fuse 1 was used, the dummy layer 5 may have another form as long as it can absorb laser light.
Further, it is preferable to use an electrically insulating material for the dummy layer 5 because a defect such as a leak does not occur even if the dummy layer 5 scatters when the dummy layer 5 explodes. Further, as shown in FIG. 4, the width of the dummy layer 5 is more effective than the width of the Al fuse 1 because the entire Al fuse 1 can be blown off.

[0015]

According to the semiconductor device according to the first aspect of the present invention, an insulating film is formed on a substrate and a fuse is formed in the insulating film. Since the dummy layer for removing the residue is provided, the residue at the time of fuse cutting can be removed.

According to the semiconductor device of the second aspect of the present invention, since the aluminum wiring below the fuse is used as a dummy layer, laser light can be effectively absorbed.

According to the semiconductor device of the third aspect of the present invention, since an electrical insulator is used as the dummy layer, even when the dummy layer explodes when the dummy layer explodes, the occurrence of defects such as leaks is prevented. can do.

According to the semiconductor device of the fourth aspect of the present invention, since the width of the dummy layer is made larger than the width of the fuse, the entire fuse can be blown out.

[Brief description of the drawings]

FIG. 1 is a plan view showing a semiconductor device according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view showing a semiconductor device according to the first embodiment of the present invention;

FIG. 4 is a sectional view showing the semiconductor device according to the first embodiment of the present invention;

FIG. 5 is a sectional view showing a conventional semiconductor device.

[Explanation of symbols]

 2a to 2c insulating film, 5 dummy layers.

Claims (4)

[Claims] In a semiconductor device having an insulating film formed on a substrate and a fuse formed on the insulating film, a dummy layer for removing a residue of the fuse at the time of cutting is provided below the fuse. Semiconductor device. 2. The semiconductor device according to claim 1, wherein an aluminum wiring below the fuse is used as a dummy layer. 3. The semiconductor device according to claim 1, wherein an electrical insulator is used as the dummy layer. 4. The method according to claim 1, wherein the width of the dummy layer is larger than the width of the fuse.
The semiconductor device according to claim 1.