Semiconductor device manufacturing: process – Coating with electrically or thermally conductive material – To form ohmic contact to semiconductive material
Reexamination Certificate
2000-04-13
2001-10-09
Nelms, David (Department: 2818)
Semiconductor device manufacturing: process
Coating with electrically or thermally conductive material
To form ohmic contact to semiconductive material
C438S362000, C257S529000
Reexamination Certificate
active
06300232
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor device equipped with a fuse for isolating a circuit from the other circuits, and a method of manufacturing the device. And the present invention relates more particularly to a semiconductor device capable of suppressing damages that may be generated at melting of the fuse to a minimum level, and a method of manufacturing the device.
2. Description of the Related Art
In order to remove a defective circuit from a semiconductor device equipped with a redundant circuit, a fuse connected to the defective circuit is melted with, for example, a laser beam. In melting the fuse through irradiation of a laser beam, there occurs sometimes a case in which damages (such as cracks) are generated due to the heat of the laser in an insulating film in the peripheral region of the fuse.
If cracks are developed in the film, infiltration of water, for example, from the outside becomes easy, resulting in a deterioration in the moisture resistance. Because of this, circuits and wirings are formed normally removed from the fuse as much as possible in order to avoid the effect of the cracks on them. More specifically, the circuits and the wirings are formed by, for example, about 100 and 10 &mgr;m, respectively, removed from the fuse. However, formation of the circuits and wirings away from the fuse results in an increase in wasteful regions, deteriorating the degree of integration of the circuit.
Techniques for suppressing the propagation of cracks to the periphery of the fuse have been disclosed, for example, in Japanese Patent Application Laid Open No. Sho 57-75442 and Japanese Patent Application Laid Open No. Hei 8-46048.
According to the technique disclosed in Japanese Patent
Application Laid Open No. Sho 57-75442, a polycrystalline silicon protective film connected to a substrate is formed directly below the fuse via an insulating film. By so doing, the heat generated at melting of the fuse is discharged to the outside through the semiconductor substrate to suppress the generation of the cracks.
According to the technique disclosed in Japanese Patent Application Laid Open No. Hei 8-46048, as shown in
FIG. 6
, after the formation of a fuse
103
in an oxide film
102
on a substrate
101
, a dummy film is formed on the oxide film
102
. After patterning the dummy film a dummy pattern
104
is formed in the periphery of the fuse
103
. In this way, cracks or the like generated at fuse melting is prevented from propagating into the region adjacent to the fuse.
However, the above techniques have the following problems.
In the technique disclosed in Japanese Patent Application Laid Open No. Sho 57-75442, an insulating film is disposed between the fuse and the protective film, so that damages (cracks or the like) may be developed before the heat of laser irradiating the fuse is transmitted to the protective film. This technique has therefore a problem in that it cannot prevent propagation of cracks generated in the insulating film into the regions adjacent to the fuse.
In the technique disclosed in Japanese Patent Application Laid Open No. Hei 8-46048, since the dummy pattern
104
is formed out of one sheet of film, cracks generated at melting of the fuse may propagate into the periphery of the fuse from the upper or lower part of the dummy pattern
104
. This technique has an additional problem in that cracks generated in the film of the dummy pattern propagate toward the substrate
101
since the dummy pattern
104
is formed only around the fuse
103
.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a semiconductor device which is capable of enhancing the degree of integration of the circuit. Moreover, it is another object of the present invention to provide a method of manufacturing a semiconductor device that is capable of enhancing the operational reliability of a semiconductor device. Furthermore, it is another object of the present invention to provide a semiconductor device that is capable of suppressing the damages to the device generated at melting of the fuse to a minimum level, and a method of manufacture of the same.
In order to attain the above objects, a semiconductor device according to a first viewpoint of this invention is a semiconductor device equipped with a fuse for isolating a circuit from the other circuits, which comprises, a lower protective film, having a width larger than that of a fuse, formed in a prescribed region on a substrate to block the propagation of damages caused by the heat (fuse melting heat) generated at melting of the fuse, a fuse formed on the lower protective film, an insulating film formed on the lower protective film so as to cover the fuse, reaching the lower protective film to enclose the fuse, and a side-face protective film formed in a groove of the insulating film for blocking the propagation of damages caused by the heat of melting of the fuse.
According to this invention, it is possible to prevent the propagation of the damages caused by the heat generated at melting of the fuse into the periphery of the fuse, by means of the lower protective film and the side-face protective film. Moreover, since the side-face protective film is formed in a groove reaching the lower protective film, there is no gap between the side-face protective film and the lower protective film. With this arrangement, it is possible to prevent the propagation of the damages generated at melting of the fuse into the periphery of the fuse through the gap between the side-face protective film and the lower protective film. Accordingly, it becomes possible to form circuits, wirings, and the like in the region directly below or in the periphery of the fuse, which enhances the degree of integration as well as the operational reliability of the semiconductor device.
The groove formed so as to surround the fuse may be constituted of two grooves facing with each other with the fuse in between, and the side-face protective film may be formed in the two grooves.
The groove may be composed of a single closed groove surrounding the fuse, and the side-face protective film may be formed in the single closed groove.
The side-face protective film may be composed of a lower side-face protective film and an upper side-face protective film formed on the lower side-face protective film, and the lower side-face protective film maybe made of the same material as that of the fuse.
The lower side-face protective film may be formed such that its connecting plane to the upper side-face protective film is substantially on the same horizontal plane as the surface of the fuse.
The side-face protective film may be formed in a plural number.
By so doing, it is possible to prevent such a large damage that cannot be prevented by a single sheet of side-face protective film.
The lower side-face protective film may be formed of a material that is less vulnerable to the generation of cracks caused by the heat of melting of the fuse.
The lower side-face protective film may be formed in a plural number.
By so doing, it is possible to prevent such a large damage that cannot be prevented by a single sheet of the lower side-face protective film.
A method of manufacturing a semiconductor device according to a second viewpoint of this invention is a method of manufacturing a semiconductor device equipped with a fuse for isolating a circuit from the other circuits comprising, a step of forming in a prescribed region of a substrate a lower protective film, having a width larger than that of the fuse, which blocks the propagation of damages caused by the heat (fuse melting heat) generated at melting of the fuse, a step of forming a fuse on the lower protective film, a step of forming an insulating film on the lower protective film so as to cover the fuse, a step of forming a groove reaching the lower protective film in the insulating film so as to surround the fuse, and a step of forming a side-face protecting film in the insulating film, which blocks the propagation of damages g
Dang Phuc T.
NEC Corporation
Nelms David
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