JPS63132449A - Fuse element - Google Patents

Abstract

PURPOSE:To prevent failure to blow a particular fuse by increasing the beam size of a fuse-blowing energy across a zigzaged wiring layer. CONSTITUTION:An insulating film 2 of SiO2 is formed on the surface of a semiconductor substrate 1. A wiring layer 3 extends for some length from one end 3a to the right side in the direction of x, and is made to turn back in zigzag. Then it extends to the left side in the direction of x, and is made to turn back is zigzag. Further it extends to the right side in the direction of x, and reaches the other end 3b. Between wiring layers 6, 6 made of aluminum, the wiring layer 3 in the form of a zigzag is connected via contact holes 5, 5. The spot diameter of a laser beam 9 to fuse the wiring layer 3 is about 6mum, and the length of a laser beam radiation window 8 in the direction of x is in the same degree as the length of linear part of the wiring layer 3. Thereby, the laser beam 9 surely fuses the wiring layer 3, even if the optical axis is off the center O of the laser beam radiation window 8.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in the following order. 'A,
Industrial field of application B1 Overview of the invention C1 Prior art [Figure 3] D. Problem to be solved by the invention E2 Means for solving the problem F1 Effect G. Examples [Figures 1 and 2 ] H2 Effects of the Invention (A, Industrial Application Field) The present invention relates to a fuse element, and particularly to a fuse element comprising a wiring layer that can be cut by energy beam irradiation.

(B. Summary of the Invention) The present invention provides a meandering structure for a fuse element made of a wiring layer that can be cut by energy beam irradiation, in order to widen the cuttable energy beam irradiation range and prevent the occurrence of cutting errors. It was formed in

(C, Conventional technology vR) [Figure 3] In semiconductor devices, such as semiconductor memories, in order to prevent a decrease in yield that occurs as a result of higher integration and larger scale, it is necessary to rescue the main circuit in addition to the main circuit. Dundancy technology is increasingly being used, such as incorporating a redundant circuit and activating the redundant circuit when the main circuit does not operate properly.

Semiconductor devices with redundant circuits that make full use of such dundancy technology are generally manufactured by the Japanese Patent Publication Publication No. 59-48
As introduced in Publication No. 543, a fuse element made of polycrystalline silicon or the like is formed on a semiconductor substrate via an insulating layer, and the fuse element is made to exist as part of a circuit consisting of a main circuit and a redundant circuit. When the circuit operates normally, the fuse element is left as is, and when there is an abnormality in the main circuit, the fuse element is blown by laser beam irradiation to operate the redundant circuit.

In addition, a semiconductor memory has been developed in which memory is stored depending on whether or not a fuse element is blown.When storing data in such a semiconductor memory, the fuse element according to the memory content is blown by laser beam irradiation. It's looking good.

3(A) and 3(B) show one conventional example of a fuse element, FIG. 3(A) is a plan view, and FIG. 3(B) is a [
- It is a cross-sectional view along the BB line of the handle 1 (A). In the figure, a is a silicon conductive substrate, b is an insulating film formed on the substrate a, and C is an insulating film made of a 5in2
It is a linear wiring layer made of polycrystalline silicon formed on +Ab, and has a line width W1 of approximately 2 μm, and both ends thereof are formed wider than the other portions. d is 5i0
2, e is a contact hole formed at both ends of the wiring layer C of the insulating film d;
f is a wiring layer made of aluminum connected to the end of wiring layer C through contact holes e, g is an overcoat film for surface protection, and a laser beam irradiation window is formed in this film g. .

When the laser beam 1 is irradiated onto the laser beam irradiation window, the wiring layer C is fused and the wiring layers f and flil are electrically JJ! The forming position and shape are set so that it can be cut. Specifically, the diameter of the laser beam i on the droplet (in addition,
The spot diameter is sufficiently wider than the width of the wiring layer C, for example, about 6 μm. ) The width W2 of the laser beam irradiation window is set to a value slightly narrower than the value obtained by subtracting the width of the wiring layer C from twice the width of the wiring layer C (approximately 10 μm).

Therefore, when cutting the fuse element, the wiring layer C can be cut by irradiating the laser beam i within the laser beam irradiation window.

(D. Problem to be solved by the invention) By the way, when irradiating a laser beam to cut a fuse element, the irradiation position of the laser beam is such that when the laser beam is irradiated, the fuse element is completely cut and the wiring is It suffices if it falls within a spatial range where layers f and f can be electrically isolated, that is, within a cuttable energy beam irradiation range,
If it deviates from this range, the wiring layer cannot be completely cut, as a matter of course. Furthermore, it is difficult to precisely control the irradiation position of the laser beam. Therefore, the energy beam irradiation range that can be cut needs to be widened by increasing both the length and the width W2, but in the conventional fuse element formed by the above-mentioned linear wiring layer C,
The size of the wiring layer in the longitudinal direction is determined by the length of the wiring layer C, and it can be made as long as necessary by increasing the length of the wiring layer C. However, the width W2 is determined by the line width of the wiring layer C and the laser beam. For example, if the line width of the wiring layer C is 2 μm and the spot diameter of the laser beam i is 6 μm, the width W2 of the energy beam irradiation range that can cut 0 is 10 (2×6-2). μm, which is relatively narrow. For this reason, as shown by the two-dot chain line, the beam could not be properly irradiated within the energy beam irradiation box 1 that can be cut, and cutting errors often occurred.

Therefore, in order to prevent cutting errors from occurring, the width (length in the y direction) of the energy beam irradiation range that can be cut is
Although it is necessary to increase W2, the width W2 cannot be increased unless the spot diameter of the laser beam i is increased. If the spot diameter of the laser beam i is increased, the beam output I5 becomes incomplete which is not desirable for cutting the wiring layer C, so the laser beam i
There was a limit to increasing the spot diameter.

Therefore, it was necessary to increase the size of the energy beam irradiation range in the wiring layer line width direction that can be cut without increasing the diameter of the laser beam i.

The present invention has been made in response to such needs, and it is possible to widen the energy beam irradiation range that can be cut by increasing the size of the energy beam irradiation range that can be cut in the wiring layer line width direction. The purpose of this is to reduce the possibility of cutting errors in the fuse element.

(F. Effect) According to the fuse element of the present invention, since the wiring layer is not formed in a straight line but in a meandering manner, the range of energy beam irradiation that can be cut can be increased in the line width direction of the wiring layer. In turn, it is possible to reduce the possibility of cutting errors in the fuse element.

(G. Embodiment) [FIGS. 1 and 2] The fuse element of the present invention will now be described in detail according to the illustrated embodiment.

1 and 2 show one embodiment of the fuse element of the present invention, FIG. 1 is a plan view, and FIG.
FIG. 2 is a cross-sectional view along line 2;

In the drawing, 1 is a silicon semiconductor substrate, 2 is an insulating film of 5 in 2 formed on the surface of the semiconductor substrate 1, and 3 is a wiring layer made of polycrystalline silicon, which has a meandering pattern. That is, the wiring layer 3 extends from one end 3a along the X direction (longitudinal direction of the wiring layer 3) to the right side in FIG. It extends to the left side of , is further folded back in a meandering manner, and extends to the right side along the X direction, reaching the other end 3b.

4 is an interlayer insulating film, and contact holes 5.5 are formed on both ends 3a and 3b of the wiring layer 3. Reference numeral 6.6 denotes a wiring layer made of aluminum, and the meandering wiring layer 3 is connected between the wiring layers 6.6 through a contact hole 5.5. Reference numeral 7 denotes an overcoat film, in which a laser beam irradiation window 8 is formed in an area that substantially coincides with the energy beam irradiation range that can be cut.

The line width of the wiring layer 3 is, for example, about 2 μm, the interval between adjacent portions of the wiring layer 3 due to the meandering is also about 2 μm, and the spot diameter of the laser beam 9 that melts the wiring layer 3 is about 6 μm. Then, X of the laser beam irradiation window 8
The length in the direction is approximately the same as the length of the straight line portion of the wiring layer 3, and the length in the X direction (line width direction of the wiring layer 3) is slightly shorter than 18 μm. When the laser beam 9 is irradiated into the irradiation window 8, the wiring layer 3 can be reliably fused even if the optical axis of the laser beam 9 is shifted from the center O of the laser beam irradiation window 8.

In other words, in the past, the wiring layer constituting the fuse element was formed in a straight line, so the size of the energy beam irradiation range that can be cut in the X direction (that is, the direction in which the wiring layer extends) was determined by increasing the length of the wiring layer. Even if the width of the energy beam irradiation range that can be cut is increased in the X direction (i.e., the line width direction of the wiring layer),
However, according to this fuse element, since the wiring layer 3 is made to meander, the energy beam irradiation range that can be cut can be expanded in the width direction (X direction) of the wiring layer 3. In addition, it is possible to widen the range of energy beam irradiation that can be cut, thereby making it difficult for the irradiation position of the laser beam to shift, thereby making it difficult to cause a cutting error in the fuse element.

In the above embodiment, the laser beam irradiation window 8 may be formed in the overcoat film 7 or may not be formed depending on the material, film thickness, laser beam output, etc. of the overcoat film 7. In both cases, the wiring layer 3 can be fused. Therefore, the overcoat film 7 is not necessarily required. Further, in the above embodiment, the wiring layer 3 constituting the fuse element was formed to connect between the aluminum wiring layers 6 and 6 formed on the semiconductor substrate 1 via the insulating film 2, but the wiring layer 3 The present invention may also be applied to a type of semiconductor device in which two diffusion layers selectively formed on the surface of the semiconductor substrate 1 are connected. Thus, the present invention can be implemented in various ways.

(H, Effect of the Invention) As described above, the present invention provides a fuse element that is formed in a meandering manner in a fuse element that is made of a wiring layer formed on a substrate and can be cut by energy beam irradiation. This is a characteristic feature.

Therefore, according to the fuse element of the present invention, since the wiring layer is not formed in a straight line but in a meandering manner, the energy beam irradiation range that can be cut can be increased in the line width direction of the wiring layer. This makes it possible to widen the energy beam irradiation range that can be cut, thereby making it difficult to cause fuse element cutting errors.

[Brief explanation of the drawing]

1 and 2 are for explaining one embodiment of the fuse element of the present invention, FIG. 1 is a plan view, FIG. 2 is a sectional view taken along line 2-2 in FIG. Figures 3 (A) and 3 (B) show a conventional example, where (A) is a plan view and Figure 3 (B) is a plan view.
is a sectional view taken along line BB in FIG. Explanation of symbols 1...Substrate, 3...Wiring layer. Fig. 1 Fig. 2 σ Plan view (,4) σ 6f'T view CB) Conventional example J Fig. 3

Claims (1)

[Claims] (1) A fuse element consisting of a wiring layer formed on a substrate and capable of being cut by energy beam irradiation, characterized in that it is formed in a meandering manner.