JPS61283163A - Semiconductor memory device - Google Patents

Abstract

PURPOSE:To enhance the melting probability of a fuse even if a melting point is displaced by forming the shape of each fuse in a redundancy circuit in two folded line shape of different angle directions or arcuate shape. CONSTITUTION:The shape of a fuse 11 is formed of at least two or more folded line shape of different angle directions, i.e., formed in folded line shape of fuse links 11a-11d. When the fuse 11 is melted, coordinates is fixed by detecting an alignment mark, melting points 13a-13d disposed at the midpoint of the links 11a-11d are decided and melted. If the positions of the points 13a-13d are, for example, displaced in the direction and at the distance designated by a vector 14 due to the detecting error of the mark, the links 11a-11c are not melted because of not along the direction and distance of the same vector 14 due to the displacement, but the link 11d is melted along this. Thus, the fuse 11 being an object can be always melted without fail.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a semiconductor memory device including a redundant circuit, and more specifically, a normal memory cell column (or row) including a defective memory cell and a spare memory cell column (or row) including a defective memory cell. This relates to an improvement in the shape of the fuse in order to replace the

[Conventional technology]

A conventional semiconductor memory device including this type of redundant circuit and the shape of its fuse are shown in FIGS. 2 and 3.

That is, in FIGS. 2 and 3, the reference numeral 1 indicates the normal memory cell column or row C and below.

2 is a spare memory cell column or row (hereinafter referred to as 1 column); 3 is a fuse portion for inactivating the normal memory cell column 1; and 4 is a fuse portion for activating the spare memory cell column 2. , and a replacement circuit including a plurality of fuse parts for setting the address of the regular memory cell column inactivated by cutting the fuse part 3; 5 is a peripheral circuit; 8 is an alignment mark; Cell row 2. The fuse section 3 and the replacement circuit 4 constitute a so-called redundant circuit, and 7 is the fuse section 3 in the redundant circuit.
fuse, 8 is its wiring, 3 is its cutting point, 1
0.10 are these contacts, and the fuse 7 is formed in a straight line shape connecting the contacts 10 and 10 at the shortest distance.

However, in the circuit configuration of this conventional example, when a defective memory cell is found in the normal memory cell column 1, the normal memory cell column containing this defective memory cell is connected to the fuse section 3 connected in series thereto. Then, by cutting at least one fuse in the replacement circuit 4, activating the spare memory cell column 2, and setting its address, the previous inactivation is performed. This is to replace the defective memory cell column with a normal memory cell column.

In this configuration, the fuse section 3 and the fuse 7 in the fuse section in the replacement circuit 4 have a linear shape, as is clear from FIG. 3, and the cutting point 9 is at one location. 2, and the coordinate system of this cutting point 9 can be fixedly determined by detecting the alignment mark 6 in FIG.

[Problem that the invention seeks to solve]

However, in such a circuit configuration of a conventional semiconductor memory device, when cutting the fuse 7, there is a possibility that the position of the cutting point 9 may shift due to an error in detecting the alignment mark 6. If the deviation is in a direction perpendicular to the longitudinal direction of the fuse 7, there is a problem in that there is a high probability of cutting failure.

Therefore, the object of this invention is to
Even if a deviation occurs in any direction, the probability of cutting the fuse 7 can be increased, and the rate of defective cutting can be reduced. An object of the present invention is to provide a semiconductor memory device of this type.

[Means for solving problems]

In order to achieve the above object, in the semiconductor memory device according to the present invention, each fuse in the redundant circuit has a shape of at least two or more polygonal lines or an arc shape having mutually different angular directions.

[For production]

In this invention, each fuse in the redundant circuit has a shape of at least two or more polygonal lines having mutually different angular directions.
Or, if you cut the fuse in an arc shape, the error in detecting the alignment mark may cause
Even if the position of the cutting point deviates by an interval in one arbitrary direction, the probability of cutting the part closest to the direction of the deviation is increased, thereby reducing the rate of defective fuse cutting.

〔Example〕

Examples of the semiconductor memory device according to the present invention will be described below.
This will be explained in detail with reference to FIGS. 1(a) and 1(b).

FIGS. 1(a) and 1(b) are explanatory plan views showing the shapes of fuses in redundant circuits according to different embodiments, respectively.

The same reference numerals as in the conventional example in FIG. 3 indicate the same or corresponding parts.

First, in the embodiment shown in FIG. 1(a), the fuse portion 3
The shape of the fuse 11 constituting the fuse 11 is defined as the shape of at least two or more broken lines having mutually different angular directions, that is, in this case, a fuse link lla diagonally to the left.
, fuse link llb in the parallel direction, fuse link tic in the diagonal right direction, and fuse link lid in the orthogonal direction.

In the embodiment shown in FIG. 1(a), when cutting the fuse 11, the coordinate system is fixed by detecting the 7-alignment mark 6 as in the conventional example, and the cutting is located at the midpoint of the fuse link lla or lid. Point) 13a to 1
3d is determined and each of these points 13a to 13d is sequentially cut. At this time, if the positions of the cutting points 13a to 13d are shifted by the direction and distance shown by the vector 14 due to a detection error of the alignment mark 6, for example, Then, due to this shift, fuse links lla and I
To, llc are not cut because they do not follow the direction and distance of the same vector 14, but the fuse link l along this
ID is disconnected, and as a result, the intended disconnection of the fuse 11 can be carried out without fail.

Furthermore, in the embodiment shown in FIG. 1(b), the shape of the fuse 12 constituting the fuse portion 3 is formed by an arc-shaped fuse link 12a, and in this case as well, the same functions and effects as in the previous example can be achieved. You get it.

〔Effect of the invention〕

As detailed above, according to the present invention, in a configuration in which each fuse in a redundant circuit can be cut from a cutting point, each fuse is shaped into at least two or more polygonal lines having mutually different angular directions. Or, since it has an arc shape, even if the cutting point deviates in one arbitrary direction, the direction of deviation can be covered by the fuse shape, increasing the probability of cutting at least part of the fuse. This can improve defects, thereby reducing programming errors in redundant circuits and significantly improving device reliability.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are plan explanatory views showing the shapes of fuses in redundant circuits according to different embodiments of the semiconductor memory device according to the present invention, and FIG. FIG. 3 is a circuit block diagram showing an outline of the storage device, and FIG. 3 is an explanatory plan view showing the shape of a fuse in a redundant circuit according to the conventional example. l... Regular memory cell column (or row), 2...
Spare memory cell column (or row), 3...Fuse section, 4...Replacement circuit, 5...Peripheral circuit, 6...
- Alignment own mark, 11.12...fuse, 13a to 13d...cutting point. Agent Masuo Oiwa Figure 1 (Q) Figure 2 Figure 3 Procedural amendment (voluntary)

Claims (1)

[Claims] A normal memory cell column (or row), a spare memory cell column (or row), and when a defective memory cell is found in the normal memory cell column (or row), a normal memory cell column containing the defective memory cell. (or row) with the spare memory cell column (or row), and each fuse section for executing this replacement switching, the coordinate system of each of the fuse sections is determined by detecting an alignment mark. In a semiconductor memory device including a redundant circuit which is fixed and can be switched by cutting from a desired cutting point, the shape of the fuse in the redundant circuit is formed into the shape of at least two or more polygonal lines having mutually different angular directions. , or a semiconductor memory device characterized by having an arc shape.