JPH0624220B2 - Semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a semiconductor device.

(Prior Art) In recent years, semiconductor manufacturing technology has been remarkably improved, and in particular, in wiring on a semiconductor device, multi-layering of two to three layers and four or more layers has 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, reference numeral 1 denotes a semiconductor substrate, and a diffusion layer 2 as a first wiring layer is formed on the surface of the substrate 1. Semiconductor substrate 1
A first insulating layer 3 is provided on the upper side, and a connection hole 4 is opened on the diffusion layer 2 of the insulating layer 3. A second 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 the connection hole 4.

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

A third wiring layer 7 made of an Al film is provided on the first insulating layers 3 and 2 and the wiring layer 5 with a second insulating layer 6 interposed therebetween. The third wiring layer 7 is formed so as to intersect with the first wiring layer 5 and passes over the connection hole 4.

(Problems to be Solved by the Invention) In such a configuration, the third wiring layer 7 is formed by the step difference of the second insulating layer 6 due to the surface shape of the first insulating layer 3.
The insulating layer 6 is poorly covered, and the film thickness becomes extremely thin at the step portion. Therefore, there is a problem that the wiring characteristics are deteriorated such as disconnection of the third wiring layer 7 and the wiring resistance is increased, and the reliability is lowered due to migration or the like.

The above-mentioned problem occurs because the length of the connection hole 4 in the longitudinal direction is longer than the width of the third wiring layer 7 and the wiring layer 7 is completely crossed by the connection hole 4, which is avoided. For this purpose, 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 second wiring layer 5 becomes uncertain, which is not preferable.

An object of the present invention is to prevent disconnection of the wiring monastery, increase in resistance, etc. due to a wiring layer passing through a step on a connection hole, and to improve wiring characteristics and reliability. It is to provide a semiconductor device to be obtained.

[Structure of the Invention] (Means for Solving the Problems) The semiconductor first to third wiring layers of the present invention have a multilayer wiring structure in which insulating layers are alternately stacked, A semiconductor device which is interconnected with a second wiring layer through a connection hole provided in the insulating layer, and through which a third wiring layer passes, the semiconductor device being wider than the third wiring layer. In the region where the third wiring layer passes, the connection holes include a plurality of connection holes arranged in the width direction of the third wiring layer and a connection hole provided outside the passage region of the third wiring layer. It is characterized by being divided.

(Operation) In the above configuration, the connection hole is divided into a plurality of areas in the region where the third wiring layer passing over the connection hole passes,
A part of the third wiring layer, which has crossed the step on the connection hole, passes through the area without the step (the area between the divided connection holes). This prevents disconnection of the third wiring layer, increase in resistance, and the like.

Further, when the connection hole wider than the third wiring layer is divided into a plurality of connection holes, the connection hole is also provided outside the region where the third wiring layer passing above the connection hole passes. Therefore, there is no inconvenience that the contact resistance between the first wiring layer and the second wiring layer increases due to the connection hole being divided into a plurality of portions in the region through which the third 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. Third like the present invention
If a plurality of connection holes arranged in the width direction of the third wiring layer in a region through which the wiring layer passes and a connection hole provided outside the passage region of the third wiring layer are divided, the area becomes smaller, 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 and the increase of the pattern area due to the division of the connection hole are not caused, and further, 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.

(Embodiment) 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. The same parts as those in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted. The difference between this embodiment and the conventional example described above is that the connection hole 4
That is, a plurality of connection holes are formed instead of. 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 second wiring layer 5.

Here, in this embodiment, in the region where the diffusion layer 2 as the first wiring layer connected by the connection hole and the third wiring layer 7 on the upper side of the second wiring layer 5 pass through, Three
Connection holes wider than the wiring layer 7 are connected to the connection holes 8b and 8c arranged in the width direction of the third wiring layer 7 and the connection hole 8a or the connection hole 8d provided outside the passage area of the third wiring layer 7. It is important to be divided into.

With such a configuration, a part of the third wiring layer 7 can pass through a region without steps. That is, in the BB cross section taken through the hole 8c in FIG. 3, the third wiring layer 7 crosses the step as shown in FIG. 2, but the holes 8b and 8c in FIG.
In the cross section taken along the line C-C passing through between and, as shown in FIG. Therefore, it is possible to prevent disconnection of the third 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.

It should be noted that 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. Further, the number of wiring layers is not limited to three and needless to say, it may be four or more.

EFFECTS OF THE INVENTION According to the present invention, a plurality of connection holes for connecting the first wiring and the second wiring layer are provided in a region where the third wiring layer passing above the connection hole passes. Due to the division, it is possible to pass a part of the third wiring layer that crosses the step on the connection hole through a region having no step, so that the disconnection of the third wiring layer and the increase in resistance are prevented. can do. Also, the third
When the connection hole wider than the wiring layer is divided into a plurality of parts, the disassembled connection hole is provided outside the region where the third wiring layer passing over the connection hole passes. Therefore, there is no inconvenience that the contact resistance between the first wiring layer and the second wiring layer increases due to the connection hole being divided into a plurality of portions in the region through which the third wiring layer passes.

That is, the connection characteristic between the first and second wiring layers depends not only on the area of the connection hole but also on the peripheral length, and the connection characteristic of the third embodiment is the same as in the present invention.
When the wiring layer is divided into a plurality of connection holes arranged in the width direction of the third wiring layer and a connection hole provided outside the passage area of the third wiring layer, the area becomes smaller, Since the peripheral length is increased, the deterioration of the connection characteristics due to the subdivision of the connection hole is hardly a 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,
2 is a sectional view taken along the line AA of FIG. 1, FIG. 3 is a plan view showing the structure of the main part of the semiconductor device according to one embodiment of the present invention, and FIG. 4 is the view of FIG. It is CC sectional drawing. 1 ... Semiconductor substrate, 2 ... Diffusion layer, 3 ... First insulating layer, 4 ... Connection hole, 5 ... Second wiring layer, 6 ... Second insulating layer, 7 ... Third Wiring layers, 8a, 8b, 8c ... Connection small holes.

Claims (1)

[Claims] 1. A multilayer wiring structure in which first to third wiring layers are alternately laminated with an insulating layer sandwiched therebetween, and a first wiring layer and a second wiring layer are provided in the insulating layer. In the semiconductor device, the third wiring layer is interconnected through the connection hole, and the third wiring layer passes over the connection hole. The connection hole wider than the third wiring layer passes through the third wiring layer. A region is divided into a plurality of connection holes arranged in the width direction of the third wiring layer and a connection hole provided outside the passage region of the third wiring layer.