Active solid-state devices (e.g. – transistors – solid-state diode – Integrated circuit structure with electrically isolated... – Passive components in ics
Reexamination Certificate
2001-11-30
2003-07-01
Chaudhuri, Olik (Department: 2823)
Active solid-state devices (e.g., transistors, solid-state diode
Integrated circuit structure with electrically isolated...
Passive components in ics
C257S530000, C257S665000, C438S130000, C438S131000, C438S132000, C438S601000, C438S662000
Reexamination Certificate
active
06586815
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor device having dummy interconnections, and particularly to a structure of a dummy interconnection having a fuse body in the semiconductor device using multi-level wiring technology and a method for manufacturing the same.
2. Description of the Related Art
In recent years, according to an increasing capacity of memory, the requirement for the dummy interconnections, or “a fuse circuit” comprising an array of dummy interconnections, each having a fuse body is growing, and the number of the dummy interconnections (fuse bodies) are swelling year by year. Therefore, an occupying space for the fuse area is also enlarged in a semiconductor chip year by year, and a yield of the product is much influenced by whether or not the required fuse bodies are successfully and selectively blown off.
FIG.
1
B and
FIG. 1A
show examples of conventional dummy interconnection structures.
FIG. 1A
is a schematic plan view, and
FIG. 1B
is the sectional view of an array of dummy interconnections, or “the fuse circuit” taken along the line IB—IB in FIG.
1
A. As shown in
FIG. 1B
, insulating layers
5
,
6
are formed on a silicon substrate
7
, between which a fuse body
2
is arranged. Both longitudinal terminal portions of the fuse body
2
are connected with fuse wirings
3
a,
3
b
via contact plugs
4
a,
4
b
of conductive materials, and there is electrical connection between the longitudinal terminal portions of the fuse body and the fuse wiring
3
a,
3
b.
A fuse window
1
, which facilitates to blow the fuse body
2
, is formed at the top surface of and in the insulating layer
5
. When a given fuse body is irradiated with an laser beam through this fuse window, the irradiated fuse body is blown away, and the electrical connection between the ends of the fuse and the fuse wiring
3
a,
3
b
are brought out of conduction.
Further, FIG.
2
A and
FIG. 2B
show a second conventional example, or other conventional dummy interconnection structures.
FIG. 2A
shows a schematic plan view of this fuse circuit, and
FIG. 2B
shows the sectional view of the fuse circuit taken along the line IIB—IIB in FIG.
2
A. Here, the same markings are given to the parts corresponding to those in the previous conventional example (first conventional example) shown in
FIGS. 1A and 1B
. In this second conventional example, to reduce the fuse area, the fuse pitch “p” is not only narrowed (however, the fuse pitch “p” in
FIG. 2B
are drawn at the same pitch as in
FIG. 1A
, for convenience), but widened blow areas
8
a
are also provided to make the heat of the laser beam to be concentrated thereon and these parts are arranged in a staggered configuration. Such a configuration is proposed so as make possible to selectively blow off the desired fuse bodies in the blow area
8
a
and also to reduce the fuse pitch “p” between adjacent fuse bodies, thereby reducing the fuse area. Here, “the fuse area” means the area in which the fuse circuit is formed.
However, the first conventional dummy interconnection configuration shown in FIG.
1
A and
FIG. 1B
had a problem that the heat of the laser beam is transported away in the longitudinal direction of the fuse body
2
because the fuse body
2
is comprised of a slim and linear electric conductor.
Also, the second conventional dummy interconnection configuration shown in FIG.
2
A and
FIG. 2B
may have caused damage to adjacent fuse bodies supposed to be not blown off with a very high possibility, this has been a factor of decrease in the manufacturing yield.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a semiconductor device allowing fuse bodies to be efficiently and easily blown off without conducting away the heat of laser beam.
Another object of the present invention is, when a fuse body is blown away, to provide a semiconductor device permitting a yield-enhancement without exerting influence on the other fuse bodies scheduled to be not blown.
A further object of the present invention is to provide a semiconductor device with dummy interconnections hardly causing damage to a part which is not irradiated with light even if pitch is narrowed between the fuse bodies.
Another object of the present invention is to provide a semiconductor device permitting to achieve a reduction in a fuse area.
Another object of the present invention is to provide a semiconductor device permitting to easily change a shape of a fuse area and enhance a selectivity and a degree of freedom in arrangements of other circuits in the surroundings of the fuse area.
A further object of the present invention is to provide a method of manufacturing a semiconductor device permitting to easily blow fuse bodies.
An even further object of the present invention is to provide a method of manufacturing a semiconductor device permitting to enhance a manufacturing yield at a time of fuse-blowing.
A first feature of the present invention lies in a semiconductor device having a plurality of dummy interconnections permitting to be selectively disconnected by using laser beam for blowing off fuse bodies. Namely, each dummy interconnection comprising: a first fuse wiring having a first terminal portion; a second fuse wiring having a second terminal portion with a given distance apart from the first terminal portion, being arranged along the same direction as the first fuse wiring is extending; a first connecting member arranged on the first terminal portion; a second connecting member arranged on the second terminal portion; and a fuse body arranged on the first and second connecting members so as to electrically connect the first and second connecting members with each other, having a length not shorter than the given distance and not exceeding a diameter of laser beam used for blowing off the fuse body.
According to the first feature of the present invention, the heat caused by irradiation of the laser beam used for selectively bringing specific dummy interconnections into a disconnected state is not transported away by conduction in the longitudinal direction of the first and second fuse wiring. Further, a possibility becomes low for the light irradiation to cause damage to adjacent fuse bodies scheduled to be not blown, and even if pitch between the fuse bodies is narrowed, a possibility to cause damage to non-irradiated part becomes low. Especially, since it is also possible for the fuse bodies to be two-dimensionally positioned at each vertex of a regular triangle, all the fuse bodies can be kept at an equal interval to other most adjacent fuse bodies. Further, it is also possible to reduce fuse pitch with a minimum fuse-to-fuse distances kept equal. Therefore, high-integration of fuse bodies is achievable without causing damage to adjacent fuse bodies.
A second feature of the present invention lies in a semiconductor device which has a fuse area comprised of a guard ring arranged in the peripheral part of the fuse area; fuse windows arranged within the guard ring; a plurality of dummy interconnections traversing the guard ring and fuse windows. And specific dummy interconnections in the fuse area can be selectively blown away to bring them into a disconnected state. Namely, each dummy interconnection comprising: a first fuse wiring having a first terminal portion; a second fuse wiring having a second terminal portion with a given distance apart from the first terminal portion, being arranged along the same direction as the first fuse wiring is extending; a first connecting member arranged on the first terminal portion; a second connecting member arranged on the second terminal portion; and a fuse body arranged on the first and second connecting members so as to electrically connect the first and second connecting members with each other, having a length not shorter than the given distance and not exceeding a diameter of laser beam used for blowing off the fuse body.
According to the second feature of the present invention, the heat caused by irradiation of the laser beam use
Berezny Neal
Chaudhuri Olik
Kabushiki Kaisha Toshiba
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