JPH03200331A - Semiconductor integrated circuit - Google Patents

Abstract

PURPOSE:To divide a current path in a bending portion into a plurality of the current paths and prevent an electromigration from being generated at a bending point by providing the bending portion of a wide wiring with a number of slits. CONSTITUTION:A plurality of slits 12 are provided in a direction wherein a wiring 11 extends and the slits 12 are also bent according to a bend in the bending portion 13 of the wiring 11. Since the wiring 11 may be separated into a plurality of thin wirings 14, the slits 12 are formed with prescribed widths according to the minimum design rule of a process concerned and may be formed by etching at the same time as the one conducted in the patterning process of the wiring 11. Thus, since the provision of the slits 12 separates the wiring 11 in the bending portion 13 into a plurality of the thin wirings 14, a current 15 flowing in the bending portion 13 is disposed to every thin wiring 14 before the wiring 11 bend. Thus, when a current density is made not larger than a prescribed value, an electromigration phenomenon is not generated.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a semiconductor integrated circuit that can prevent electromigration damage caused by localized current concentration at bent portions of wiring.

(b) Conventional technology Higher integration and higher density of integrated circuits have been achieved than in the past.
As devices become smaller, the width of wiring for interconnections becomes finer. On the other hand, the power line (
It is also true that wiring thicker than signal lines, etc. is required in order to secure the required current capacity and suppress the current density below a certain value) and to suppress the voltage drop due to resistance. Therefore, even if the manufacturing process shifts to the submicron rule, the thick wiring will always extend at several locations.

(C) Problems to be Solved by the Invention However, since current tends to flow through the part with the least resistance, for example, as shown in Figure 3, the wiring (
At the part where 1) is bent at a right angle, the current (2) is connected to the wire (1).
) (point A in the figure). Wiring (1
) The thicker the line width, the stronger the degree of concentration, and as a result, the current density exceeds a certain value (approximately 106 A/cm") and an electromigration phenomenon occurs (
For example, Japanese Patent Application Laid-Open No. 64-45142). When this phenomenon occurs, short circuits occur due to wire breaks and hillocks, which causes a reduction in the reliability of the wires.

(d) Means for Solving the Problems The present invention has been made in view of the above-mentioned conventional drawbacks, and the wiring (
By providing a slit (12) in the bent portion (13) of the wiring (11) in parallel to the extending direction of the wiring (11), a semiconductor integrated circuit is provided that is prevented from being destroyed by electromigration.

(*) Effect According to the present invention, by providing the slit (12), the wiring at the bending part (13) is divided into a plurality of thin wires (14), so that the current (15) is applied to each thin wire. The current flows through each wire (14), which alleviates the current concentration at the bending point (A).

(f) Example The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a plan view showing one embodiment of the present invention. In the figure,
(11) is a wiring, and (12) is a slit.

The wiring (11) interconnects individual semiconductor devices constructed by forming diffusion regions and gate electrodes (polysilicon, polycide, etc.) on a silicon semiconductor substrate, and is made of aluminum (AP) or aluminum. It can be formed by depositing silicon (Ajl!-5t) by evaporation or sputtering and patterning by a photoresist process.

It is up to you which layer of the multilayer wiring it is located, but since you want to use the lower layer to improve the degree of integration, the power supply line (V
Wires (11) with a line width of 100μ to 200μ, such as Dn; etc. can be mentioned.

As is clear from the figure, the slit (12) is connected to the wiring (1
1) A plurality of wires are provided parallel to the extending direction of the wiring (
At the bending part (13) of 11), the slit (12) is also bent according to the bending. The width of the slit (12) does not need to be wide, and the wiring (11) has multiple thin wiring (1
4), so it is formed to have a constant width (3 to 5 μm) according to the minimum design rule of the process.

The slits (12) may be formed by etching simultaneously with the patterning process of the wiring (11). Also, from one thin wire (14) to another thin wire (14) inside it,
) to prevent the current (15) from flowing to the bent part <13).
In this case, the slits (12) must be continuous. Since the wiring (12) extends over an (interlayer) insulating film such as Sin, SiN, etc., the insulating film is exposed inside the slit (12).

According to this configuration, the wiring (11) of the bent portion (13) is separated into a plurality of thin wires (14) by providing the slit (12), so that the electric current flowing through the bent portion (13) is reduced. ffff(15) is distributed to each thin wire (14) before the wire (11) is bent. The electromigration phenomenon refers to the electromigration phenomenon when the wiring (11) has a certain value (
Refers to the phenomenon in which Ae atoms, which are the material, move in the direction of electron movement when a large current of approximately 10'A/an'' or more flows, and voids are generated in the traces where A4 atoms have moved. The wiring (1
1) failure occurs. In addition, hillocks occur at locations where AP atoms move and accumulate, which causes short-circuit failures between adjacent wirings. In other words, if the current density is kept below a certain value, electromigration will not occur.

Therefore, in the present invention, the current (15) is distributed to each thin wire (14), and the thin wires (14) are individually separated by the slits (12). ) is not concentrated at the - point and the current density does not exceed the above-mentioned constant value, so electromigration phenomenon can be prevented.

FIG. 2 shows a second embodiment of the invention. The difference from the previous embodiment is that the inner slit (12
) extends far into the distance. With this shape, the bending point (13) will be determined according to the characteristics of the current (15)
) (for example, 13a in the figure) is always captured by the thin wire closest to the position (for example, 14a in the figure), so that the current (15) can be dispersed more reliably than in the previous embodiment.

Furthermore, in the case where the lower layer wiring (16) extends below the wire (11) with a large line width via an interlayer insulating film, disconnection of the lower layer wiring (16) due to stress migration can also be prevented. Stress migration is caused by stress due to thermal expansion of the AQ and insulating film, and the thicker the line width, the greater the amount of stress applied to other lines, causing disconnection of the underlying wiring (16). By providing the slits (12) as in the present invention, stress is also dispersed, thereby preventing disconnection of the underlying wiring (16). This effect is the first. The same applies to the second embodiment.

(g) As described in detail, according to the present invention, a large number of slits (12) are provided in the bent portion (13) of the wide wiring (11), so that the current path in the bent portion (13) is It has the advantage that electromigration can be prevented from occurring at the bending point (A in the figure) by dispersing it into a plurality of parts.

In addition, in the configuration in which the lower layer wiring (16) is provided under the bent portion (13), the stress exerted on the lower layer wiring (16) by the wide wiring (11) can be dispersed by the slit (12). This has the advantage that failures due to stress migration (x6) can also be prevented.

Therefore, according to the present invention, a highly reliable multilayer wiring structure can be achieved.

[Brief explanation of drawings]

Figures 1 and 2 are plan views for explaining the present invention, and Figure 3 is a plan view for explaining the present invention.
The figure is a sectional view for explaining a conventional example.

Claims (3)

[Claims] (1) In a semiconductor integrated circuit having an electrode wiring extending at a right angle or at an angle close to a right angle, a plurality of slits extending parallel to the extending direction of the electrode wiring are provided in the bent part. A semiconductor integrated circuit characterized by: (2) The semiconductor integrated circuit according to claim 1, wherein the slit extends far inside the bent portion. (3) The semiconductor integrated circuit according to claim 1, wherein a lower wiring layer overlaps and extends over the bent portion with an interlayer insulating film interposed therebetween.