JPH0783054B2 - Semiconductor device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device.

[0002]

2. Description of the Related Art Recent improvements in semiconductor manufacturing technology are remarkable, especially in wiring on a semiconductor device from two layers to three layers.
The number of layers and the number of layers of four or more have been realized.
However, on the other hand, as the number of wiring layers increases, the stepped shape of the semiconductor surface becomes more and more complicated, and problems such as deterioration of wiring characteristics including disconnection and deterioration of reliability have come to the surface. In particular, with regard to connection holes for connecting desired wiring layers, it has been generally considered that it is common and advantageous to open the connection holes as large as possible in the past. There was an inconvenience.

FIG. 1 is a plan view showing a structure of a main part of a conventional semiconductor device, and FIG. 2 is a view showing a cross section taken along the line AA of FIG. In the figure, 1 is a semiconductor substrate, and a diffusion layer 2 is formed on the surface of the substrate 1. A first insulating layer 3 is provided on the semiconductor substrate 1, and a connection hole 4 is opened on the diffusion layer 2 of the insulating layer 3. A first wiring layer 5 made of an Al film is provided on the insulating layer 3, and the wiring layer 5 is connected to the diffusion layer 2 via a connection hole 4.

Here, the connection hole 4 is relatively large in the region where the diffusion layer 2 and the wiring layer 5 overlap in order to ensure the connection between the diffusion layer 2 and the wiring layer 5, and the length of the wiring layer 5 is large. It is formed long in the direction.

Further, the first insulating layer 3 and the first wiring layer 5
A second wiring layer 7 made of an Al film is provided on the upper side of the second insulating layer 6. The second wiring layer 7
Are formed so as to intersect with the first wiring layer 5 and pass over the connection hole 4.

[0006]

SUMMARY OF THE INVENTION With such a configuration,
The second wiring layer 7 has poor step coverage of the second insulating layer 6 due to the surface shape of the first insulating layer 3 and thus has poor coverage with the insulating layer 6, resulting in a very thin film thickness at the step portion. Become.
For this reason, there is a problem that the wiring characteristics are deteriorated such as a step break of the second wiring layer 7 and the wiring resistance is increased, and the reliability is lowered due to migration and the like.

The above-mentioned problem occurs because the connecting hole 4 is longer in the longitudinal direction than the width of the second wiring layer 7 and the wiring layer 7 is completely crossed by the connecting hole 4. In order to avoid this, the connection hole 4 may be formed shorter than the width of the wiring layer 7. However, in this case, the area of the connection hole 4 becomes small, and the connection between the diffusion layer 2 and the first wiring layer 5 becomes uncertain, which is not preferable.

An object of the present invention is to prevent the wiring layer from being stepped or having its resistance increased due to the wiring layer passing through a step on the connection hole, thereby improving the wiring characteristics and reliability. It is to provide a semiconductor device which can be improved.

[0009]

In order to achieve the above object, a semiconductor device of the present invention has a multilayer wiring structure in which insulating layers and wiring layers are alternately laminated on a semiconductor substrate having a diffusion layer on the surface. The diffusion layer and the first wiring layer are interconnected through a connection hole provided in the insulating layer, and the second wiring layer passes over the connection hole. The connection hole, which is wider than the layer, is provided in a region through which the second wiring layer passes, and is provided outside the passing region of the plurality of connection holes arranged in the width direction of the second wiring layer and the second wiring layer. It is characterized in that it is divided into two connecting holes.

[0010]

In the above structure, the second passage that passes over the connection hole is used.
Since the connection hole is divided into a plurality of parts in the region through which the wiring layer passes, a part of the second wiring layer that has crossed the step on the connection hole has a step-free region (connects with the divided connection hole). The area between the holes). As a result, the disconnection of the second wiring layer and the increase in resistance are prevented.

Further, when the connecting hole wider than the second wiring layer is divided into a plurality of connecting holes, the connecting hole is also provided outside the region where the second wiring layer passing above the connecting hole passes. There is.
Therefore, there is no inconvenience that the contact resistance between the diffusion layer and the first wiring layer is increased due to the division of the connection hole into a plurality of areas in the region where the second wiring layer passes. That is, the connection characteristic between the wiring layers via the connection hole depends not only on the area of the connection hole but also on the peripheral length. Like the present invention, the second
If a plurality of connection holes arranged in the width direction of the second wiring layer in a region through which the wiring layer passes and a connection hole provided outside the passage region of the second wiring layer are divided, the area is reduced, but Since the length is increased, the deterioration of the connection characteristics due to the subdivision of the connection hole hardly poses a problem.

Further, the addition of a pattern or the increase of the pattern area due to the division of the connection hole does not occur, and the division of the connection hole pattern does not involve a process change. Therefore, the wiring characteristics and reliability can be improved without changing the layout or the process.

[0013]

FIG. 3 is a plan view showing the structure of the main part of a semiconductor device according to an embodiment of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted.
This embodiment is different from the above-mentioned conventional example in that a plurality of connection holes are formed instead of the connection holes 4.
That is, in the first insulating layer 3, four connection small holes 8a, 8b, 8c, 8d are linearly arranged along the length direction of the first wiring layer 5.

Here, in the present embodiment, in the region where the diffusion layer 2 connected by the connection hole and the second wiring layer 7 above the first wiring layer 5 pass, this second wiring layer is passed. The connection hole wider than 7 is divided into the connection holes 8b and 8c arranged in the width direction of the second wiring layer 7 and the connection hole 8a or the connection hole 8d provided outside the passage area of the second wiring layer 7. Is important.

With such a configuration, the second wiring layer 7
Can pass through a stepless region. That is, in the BB cross section taken through the hole 8c in FIG. 3, the second wiring layer 7 crosses the step as shown in FIG. 2, but the hole 8b in FIG.
In the cross-section taken along the line C-C as seen from the arrow passing through between No. 8c and No. 8c, as shown in FIG. Therefore, it is possible to prevent disconnection of the second wiring layer 7 and increase in resistance due to step disconnection at the step portion, reduction in film thickness, and the like, and it is possible to improve wiring characteristics and reliability.

The present invention is not limited to the above-described embodiments, and various modifications can be carried out without departing from the scope of the invention. For example, the number of divisions of the connection hole is not limited to four and can be increased or decreased as appropriate.

[0017]

According to the present invention, the connection hole for connecting the diffusion layer and the first wiring layer is divided into a plurality of areas in the region where the second wiring layer passing above the connection hole passes. As a result, it is possible to pass a part of the second wiring layer that crosses the step on the connection hole through a region having no step, so that it is possible to prevent disconnection of the second wiring layer and increase in resistance. You can Further, when the connection hole wider than the second wiring layer is divided into a plurality of portions, the connection hole is also provided outside the region where the second wiring layer passing above the connection hole passes. Therefore, there is no inconvenience that the contact resistance between the diffusion layer and the first wiring layer increases due to the connection hole being divided into a plurality of portions in the region where the second wiring layer passes. That is, the connection characteristics between the diffusion layer and the first wiring layer depend not only on the area of the connection hole but also on the peripheral length, and as in the present invention, the connection characteristics of the second wiring layer in the region through which the second wiring layer passes. If the connection hole is divided into a plurality of connection holes arranged in the width direction and the connection hole provided outside the passage area of the second wiring layer, the area becomes smaller, but the peripheral length increases, so the connection hole should be subdivided. The deterioration of the connection characteristics due to the above causes almost no problem.

Further, there is no need to add a pattern or increase a pattern area by dividing the connection hole, and since the connection hole pattern is divided, the process is not changed. Therefore, it is possible to improve the wiring characteristics and the reliability without changing the layout and the process.

[Brief description of drawings]

FIG. 1 is a plan view showing a structure of a main part of a conventional semiconductor device.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a plan view showing a structure of a main part of a semiconductor device according to an embodiment of the present invention.

FIG. 4 is a sectional view taken along the line C-C of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Semiconductor substrate 2 ... Diffusion layer 3 ... 1st insulating layer 4 ... Connection hole 5 ... 1st wiring layer 6 ... 2nd insulating layer 7 ... 2nd wiring layer 8a, 8b, 8c, 8d ... Small connection Hole

Claims (1)

[Claims] 1. A multilayer wiring structure in which an insulating layer and a wiring layer are alternately laminated on a semiconductor substrate having a diffusion layer on the surface, and the diffusion layer and the first wiring layer are provided in the insulating layer. In the semiconductor device, the second wiring layer is interconnected through the connection hole, and the second wiring layer passes over the connection hole. The connection hole wider than the second wiring layer passes through the second wiring layer. A region is divided into a plurality of connection holes lined up in the width direction of the second wiring layer and a connection hole provided outside the passage region of the second wiring layer.