JPH0337734B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The object of the present invention is to prevent disconnection of upper layer electrodes at stepped portions of the interlayer insulating layer in multilayer wiring having an interlayer insulating layer formed of photosensitive polyimide resin. It is.

In the conventional method, when photosensitive polyimide resin is used as an interlayer insulation layer, an interlayer insulation layer pattern is formed by a photorin process and through holes etc. are provided. Since the rise exceeds the thickness of the layer, there is a drawback that the upper layer electrode is likely to be disconnected at the step portion when forming the upper layer electrode. This drawback will be explained based on the drawings. FIG. 1 is a cross-sectional and plan view showing an example of a conventional multilayer wiring structure in which a photosensitive polyimide resin is used as an interlayer insulating layer. When forming the through hole 2 in the interlayer insulating layer 1, a photolithography process is used, but in this case, it is inevitable that the stepped portion 3 of the through hole 2 will be raised to a thickness greater than the required thickness. Because this bulge is sharp, as shown in FIG. 2, when the upper layer electrode 4 is deposited, the upper layer electrode 4 is disconnected at the stepped portion 3 of the interlayer insulating layer 1.
Alternatively, as shown in FIG. 3, when the upper layer electrode 4 is formed by a photolithography process even if there is no disconnection during vapor deposition, since the photoresist layer 7 at the stepped portion 3 is thin, the upper layer electrode 4 is formed at the stepped portion 3.
is eroded by the etching solution and breaks. As described above, in the conventional multilayer wiring structure using photosensitive polyimide resin, disconnection of the upper layer electrode is likely to occur due to sharp bulges at the stepped portions of the interlayer insulating layer.

The present invention is aimed at preventing disconnection of the upper layer electrode at such a stepped portion of the interlayer insulating layer, and is characterized by providing a pseudo electrode in addition to the lower layer electrode wiring pattern below the stepped portion. As shown in FIG. 1, this method actively utilizes the fact that the interlayer insulating layer made of photosensitive polyimide resin is formed by directly reflecting the step difference caused by the lower layer electrode wiring pattern.

The present invention will be explained in detail below based on the drawings. FIGS. 4 and 5 are diagrams showing preferred application examples of the present invention. As shown in FIG. 4, a pseudo electrode 8 is provided adjacent to the lower layer electrode 6 which is electrically connected to the upper layer electrode 4 via the through hole 2. Although the swell of the interlayer insulating layer 1 at the stepped portion 3 is unavoidable in this case as well, since there is also a step due to the pseudo electrode 8, the stepped portion 3 does not have a sharp bulge as in the conventional case, and the stepped portion as a whole is 3 can be flattened. Alternatively, as shown in FIG. 5, the same effect can be achieved by widening the width of the portion of the lower layer electrode 5 adjacent to the lower layer electrode 6 that is parallel to the through hole 2 toward the through hole 2 side. Can be done.

As described above, according to the present invention, sharp bulges in the step portion of the interlayer insulating layer can be alleviated by using the step formed by the pseudo electrode provided in the lower layer.
It is possible to prevent wire breakage at the stepped portion of the interlayer insulating layer of the upper electrode, which is likely to occur when a photosensitive polyimide resin is used as the interlayer insulating layer.

[Brief explanation of the drawing]

Figure 1 is a diagram showing an example of a conventional multilayer wiring structure when polyimide resin is used as an interlayer insulation layer, Figures 2 and 3 are diagrams showing drawbacks of the conventional method, and Figures 4 and 5 are FIG. 3 is a diagram showing a preferred application example of the present invention. 1... Interlayer insulation layer using polyimide resin, 2
. . . Through hole, 3 . . . Stepped portion of interlayer insulating layer, 4 . . . Upper layer electrode, 5 .

Claims (1)

[Claims] 1. In a multilayer wiring structure consisting of a lower layer electrode wiring pattern, an interlayer insulating layer formed of a photosensitive polyimide resin, and an upper layer electrode wiring pattern,
A multilayer wiring structure characterized in that, in addition to the lower layer electrode wiring pattern, a pseudo electrode is provided below the stepped portion of the interlayer insulating layer.