JPH0228930A - Wiring pattern - Google Patents

Abstract

PURPOSE:To prevent disconnection and to improve reliability by making line widths of a wiring pattern at a lower potential are larger than ones at a higher potential. CONSTITUTION:A wiring pattern 3 in which the line width of a lower potential is larger than that of a higher potential is provided. According to such a pattern 3, a disconnection does not occur even after an electromigration generated upon movement of a wiring material from a lower potential to a higher potential since the supply of the material is large near the position L of lower potential. An arrow shows the electromigration movement. When the line width of the higher potential is excessively thin than that of the lower potential, the moved material is raised to be possibly disconnected. Accordingly, the ratio of the line width of higher voltage to lower voltage is desirably ranged A:B at 1:1.1-1:10 and more preferably A:B=1.1.5-1.2 approximately.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to wiring patterns in thin film transistor driven contact type sensors or LSIs in general.

Conventional technology Conventionally, in the wiring of this type of device, etc., AQWi
! Failures such as disconnection due to electromigration of wires and the like have become a problem. "Electromigration" refers to a phenomenon in which atoms forming a conductor exposed to high temperatures move through direct exchange of kinetic energy from electrons carrying direct current. 202. Due to ctromigration, wiring material partially moves to another location, resulting in disconnections at locations where material (substance) is removed and short circuits at locations where material is accumulated.

Therefore, this type of device requires countermeasures against electromigration. In this regard, the conventional countermeasure is
``Reliability of metallization (
As described in 1) -Second Cutromigration-, we are trying to improve the durability of wiring by improving film quality such as material selection, deposition conditions, annealing conditions, etc.

Problems to be Solved by the Invention According to such a method of changing the film quality, new problems such as wiring resistance and poor contact arise, resulting in a lack of reliability in the wiring.

Means for Solving the Problems In the wiring pattern, the line width of the lower potential line is made thicker than the line width of the higher potential side.

When considering electromigration failures in working wiring, the wiring material often moves from the lower potential to the higher potential, causing disconnection at the lower potential location.

At this time, since the line width at the lower potential side is thicker, even if the wiring material moves from the lower potential side to the higher potential side, the lower potential point will not break. .

Embodiment A first embodiment of the present invention will be explained based on FIG. In this embodiment, as a countermeasure against electromigration, instead of conventional film quality improvement, attention is paid to the wiring pattern shape, and the pattern shape is improved.

First, the conventional method will be discussed with reference to FIGS. 6 and 7. Conventionally, regardless of the film quality, the line width of the wiring pattern 1 is formed in parallel as shown in the figure. Here, as a failure due to electromigration, for example, wiring materials such as AQ move from the side with a lower potential to the side with a higher potential,
As a result of electromigration, as shown in FIG. 7, a disconnection 2 often occurs at a location in the wiring pattern 1 where the potential is lower.

Therefore, in this embodiment, as shown in FIG. 1(a), the wiring pattern 3 is made such that the line width of the lower potential side is wider than the line width of the higher potential side. According to such a wiring pattern 3, even after electromigration as shown in FIG. 1(b) in which the wiring material moves from the lower potential to the higher potential, the lower potential location Since there is a large supply of material near the area, disconnection will not occur. The arrows in FIG. 1(b) indicate electromigration movement.

However, if the line width of the higher potential line is made too thin than that of the lower potential line, as can be seen from FIG. 7, the transferred wiring material may swell up and break the line there. Therefore, the ratio of the line width A at higher voltage to the line width B at lower voltage, A:B, is in the range of about l:1.1 to 1:10, more preferably A:B=1:l. , the ratio is preferably about 5 to 1:2.

Next, a second embodiment of the present invention will be described with reference to FIGS. 2 and 8. First, as shown in FIG. 8, at a location M where the thickness of the wiring pattern 4 changes drastically, the ease with which the material moves changes. As a result, wire breaks are likely to occur at locations in the wiring pattern 4 where the line width is narrow. In the illustrated example, the line with the thicker line width is located at the lower potential. In this embodiment, in the wiring pattern 4 where the wiring thickness changes, the portion M where the thickness changes is formed into an arcuate portion 5 with a radius of curvature R as shown in FIG. The number of parts is reduced and the ease of material movement is made uniform as shown by the arrows in Figure 2.

The position of the center of the arcuate portion 5 and the size of the radius R are arbitrary, as long as the corner portions are arcuate, and the shape is not limited to the arcuate shape, but may be any smoothly curved shape. Further, in this embodiment, the arcuate portions 5 are formed on both sides, but they may be formed on at least one side.

FIG. 3 shows a modified example, in which the corner portion of the wiring pattern 4 where the thickness changes is formed into a stepped portion 6 to equalize the ease of movement of the material. In this case as well, the width dimensions C and D and the number of steps of the stepped portion 6 are arbitrary, as long as the corner portions are stepped. It may be only one side.

FIG. 4 shows a different modification, in which the corner part of the part M where the thickness of the wiring pattern 4 changes is shaped into a tapered part 7,
It equalizes the ease of movement of materials. The dimensions E and F of this tapered portion 7 are arbitrary.

FIG. 5 shows a further modified example, in which the corners of the portions M where the thickness of the wiring pattern 4 changes are shaped into a stepped tapered portion 8, which is a combination of a stepped shape and a tapered shape, to make it easier for the material to move. It is a homogenized version. The number of steps, shape, etc. of the stepped tapered portion 8 in this case are shown in Fig. 5(a) (
b) An appropriate pattern may be used as exemplified in (c).

Effects of the Invention As mentioned above, the present invention focuses on the direction in which wiring material moves depending on the level of potential, and makes the line width of the lower potential line thicker than the line width of the higher potential side, so that the movement of the wiring material is reduced. Even if there is, the supply of material is sufficient at the lower potential point, there will be no disconnection, and the product will be durable, and the wiring film quality itself may be the same as usual, so there will be no problems after wiring. , it becomes highly reliable.

[Brief explanation of the drawing]

FIG. 1 shows a first embodiment of the present invention, FIG. 1(a) is a plan view before electromigration, and FIG. 1(b) is a plan view before electromigration.
is a plan view after electromigration, FIG. 2 is a plan view showing the second embodiment of the present invention, FIG. 3 is a plan view showing a modified example, FIG. 4 is a plan view showing a different modified example, and FIG. 6 is a plan view showing a conventional example before electromigration, FIG. 7 is a plan view after electromigration, and FIG.
) is a plan view, FIG. 7(b) is a sectional view thereof, and FIG. 8 is a plan view showing a conventional example.

Claims (1)

[Claims] A wiring pattern characterized in that the line width of the lower potential line is wider than the line width of the higher potential line.