JPH0529475A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To make it possible to make a good connection of a contact wiring regardless of an increase in the aspect ratio of a contact hole. CONSTITUTION:A contact hole 13 is opened in interlayer insulating films 11 and 12 and, thereafter, a conductive material layer 14a having a good converge is made to cover on the film 12 including the hole 13 and at the same time, an entire surface etchback is performed to bury this covered layer 14a in the hole 13 and a conductive material layer 14 is left. Thereby, after the effective depth of the hole 13 is reduced, a wiring layer 15 is made to connect to this layer 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a method of manufacturing the same, and more particularly, to improvement of a contact structure in an electrode wiring of a semiconductor device and a method of forming the same.

[0002]

2. Description of the Related Art The technological innovation of semiconductor devices (semiconductor devices) is extremely remarkable, and in particular, the progress of miniaturization technology of the device structure is progressing so far as it is said to be progressing minute by minute. The situation is getting faster. Under these circumstances, elements constituting a semiconductor device, such as transistors and capacitors, element isolation, contacts, wirings, etc., have been miniaturized. The contact structure in (1) is no exception, and the opening diameter of the contact hole tends to be miniaturized in accordance with the miniaturization of the device itself.

Here, as shown in FIG. 5, in the contact structure in wiring of this kind of electrode or the like, which is formed by a generally known means, with respect to the interlayer insulating film 1. Regarding the selectively opened contact hole 2, when the diameter of the contact hole 2 is D and the depth is H, so-called [aspect ratio = H / D] is defined as one of the figure merits. It

Further, in the usual case, the reduction for miniaturization in the semiconductor device is performed mainly in the direction of the plane, so that even if the diameter D of the contact hole 2 is reduced, this is not the case. Correspondingly, the depth H is not necessarily reduced, but the aspect ratio is gradually increased. As a result, after the contact hole 2 is opened, the conductivity as a wiring formed inside the opening is increased. In some cases, the coverage of the material cannot be obtained as desired, and the wiring itself may not be properly connected, resulting in connection failure or even disconnection.

Therefore, in the prior art, in order to avoid such connection failure and disconnection of wiring such as electrodes, for example, when there are two or more layers of interlayer insulating film, on the first layer interlayer insulating film. Wiring technique means for utilizing the first wiring layer formed in the above as a wiring pad of a contact in the second interlayer insulating film has been introduced.

That is, this wiring technique means, as shown in FIG. 6, with respect to the first wiring layer 3 formed through the first contact hole 2 in the first interlayer insulating film 1.
The second layer of the second interlayer insulating film 4 for insulatingly covering the second layer
The contact hole 5 is selectively opened, the first wiring layer 3 is formed here, and is used as a wiring pad of the second wiring layer 6 formed through the second contact hole 5.

[0007]

However, as described above, the first wiring layer 3 formed on the first-layer interlayer insulating film 1 is replaced with the second wiring in the second-layer interlayer insulating film 4. In the wiring technology means used as the wiring pad of the layer 6, the second
As the aspect ratio of the contact hole 5 increases, there is an inconvenience that the recessed portion 7 as a pad on the first wiring layer 3 becomes an obstacle to the formation of the contact structure by the second wiring layer 6. In other words, in other words, the insulating material used for forming the second interlayer insulating film 4 at the time of forming the second interlayer insulating film 4 after the formation of the first wiring layer 3 is When left in the recessed portion 7, the remaining insulating material causes instability of contact resistance in wiring such as electrodes, connection failure, and disconnection.

The present invention has been made in order to solve such conventional problems, and an object thereof is to achieve good contact wiring connection regardless of an increase in the aspect ratio of the contact hole. The present invention is to provide a semiconductor device of this type, a manufacturing method thereof, and a contact structure in wiring such as electrodes, and a forming method thereof.

[0009]

In order to achieve the above object, a semiconductor device according to the present invention and a method for manufacturing the same are provided with a contact structure in a wiring such as an electrode and a method for forming the same, in which openings are selectively formed. The contact hole is temporarily filled with a conductive material layer having a good covering property, and then the wiring layer is connected to this conductive material layer.

That is, according to the present invention, in the contact structure of the semiconductor device, the inside of the contact hole selectively formed in the interlayer insulating film is filled with a conductive material layer having a good covering property, and the contact hole of the contact hole is formed. It is a semiconductor device characterized in that an effective depth is reduced and a wiring layer is selectively connected to the conductive material layer.

Further, according to the present invention, in a contact structure of a semiconductor device, a step of selectively forming a contact hole in an interlayer insulating film, and a conductive film having good coverage on the interlayer insulating film including the contact hole. Of a conductive material, a step of etching back the coated conductive material to leave a conductive material layer buried in a contact hole, and a wiring layer is selectively formed with respect to the conductive material layer. And a wiring layer is connected through the conductive material layer after reducing the effective depth of the contact hole by burying with the conductive material layer. Is a manufacturing method.

[0012]

Therefore, in the contact structure in the wiring such as the electrode and the method for forming the same according to the present invention, the inside of the selectively formed contact hole is once filled with the conductive material layer having a good covering property. Since the wiring layer is connected to this conductive material layer after reducing the effective depth of the contact hole, good wiring connection is performed even for a contact hole having a large aspect ratio. be able to.

[0013]

Embodiments of a semiconductor device and a method of manufacturing the same according to the present invention will be described below in detail with reference to FIGS.

FIGS. 1 to 4 are schematic diagrams sequentially showing main steps of a method of manufacturing a semiconductor device to which an embodiment of the present invention is applied, in which a contact structure in an electrode wiring and a method of forming the same are sequentially shown. It is a cross-sectional view, and in this embodiment, the case of having an interlayer insulating film extending over two layers is dealt with.

That is, according to the method of this embodiment, the first and second interlayer insulating films 1 sequentially deposited and formed.
When contact wiring connection is made through the wirings 1 and 12, first, the first and second interlayer insulating films 11 and 1 are formed.
For 2, the common contact hole 13 for taking out the corresponding electrode is selectively opened by the well-known photolithography method and etching technique (see FIG. 1).

Then, the common contact hole 1 is thus formed.
On the second interlayer insulating film 12 in which the openings 3 are formed, a conductive material (for example, Poly.Si, W.Si, W deposited by the CVD method) layer 14a having a good covering property is formed.
Then, the corresponding electrode and the like are taken out by the conductive material layer 14a (see FIG. 2).

After that, the conductive material layer 14a for taking out the corresponding electrodes and the like is entirely etched back by a dry etching technique. In this case, the conductive material layer 14a is opened on the opening surface of the contact hole 13. By etching to a position slightly lower than that, the buried conductive material layer 14 is left in the contact hole 13 (see FIG. 3).
reference).

Further, the wiring layer 15 is selectively formed as desired on the second interlayer insulating film 12 including the exposed portion of the buried conductive material layer 14 in the contact hole 13 to form a corresponding electrode. This constitutes a contact structure for taking out (see FIG. 4).

Therefore, according to the contact structure in the wiring such as the electrode having the above-described structure, when the wiring connection is made to the contact hole 13 having a relatively large aspect ratio, the inside of the contact hole 13 is temporarily buried. 14
This buried conductive material layer 1 after being buried by
Since the wiring layer 15 is formed to include the exposed portion of No. 4, even if the covering property of the wiring material itself used as the wiring layer 15 is poor, a connection failure, a disconnection, etc. do not occur, and the wiring layer 15 is always good. Since the electrode wiring according to the connection form can be formed, and since the entire surface is covered with the conductive material layer 14a and the entire surface is etched back to form the embedded conductive material layer 14, the embedded conductive material layer 1
There is no fear that a recess will be formed on the exposed surface of No. 4, and naturally there is no intervention of foreign matter into the recessed portion as in the conventional case.

[0020]

As described above in detail with reference to the embodiments,
According to this invention, the effective depth of the contact hole is reduced by filling the inside of the selectively formed contact hole with the conductive material layer having a good covering property. Since the wiring layer is connected to the conductive material layer, good wiring connection can be performed even in a contact hole having a large aspect ratio. As a result, the wiring in the conventional contact structure is obtained. Instability of contact resistance, connection failure, disconnection, etc. can all be improved, and reliable and stable wiring connection can be formed very easily.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing a first step of a method of forming a contact structure in a wiring such as an electrode to which an embodiment of the present invention is applied.

FIG. 2 is a cross-sectional view schematically showing a second step in the method according to the first embodiment.

FIG. 3 is a cross sectional view schematically showing a third step in the method of the above embodiment.

FIG. 4 is a cross-sectional view schematically showing a fourth step in the method according to the above embodiment.

FIG. 5 is an explanatory diagram showing an aspect ratio of a general contact hole.

FIG. 6 is a sectional view schematically showing a schematic configuration of a contact structure in a wiring such as an electrode according to a conventional example.

[Explanation of symbols]

11 First interlayer insulating film 12 Second interlayer insulating film 13 Contact hole 14a Conductive material layer with good coverage 14 Embedded conductive material layer 15 wiring layers

Claims (2)

[Claims] 1. In a contact structure of a semiconductor device,
By embedding a conductive material layer with good coverage in the contact hole that is selectively formed with respect to the interlayer insulating film,
While reducing the effective depth of the contact hole,
A semiconductor device, wherein a wiring layer is selectively connected to the conductive material layer. 2. In a contact structure of a semiconductor device,
A step of selectively forming contact holes in the interlayer insulating film; a step of coating a conductive material having a good covering property on the interlayer insulating film including the contact holes; and a step of forming the coated conductive material. The method includes at least a step of etching back the entire surface to leave a conductive material layer buried in the contact hole, and a step of selectively forming a wiring layer with respect to the conductive material layer. A method for manufacturing a semiconductor device, which comprises reducing the effective depth of a hole and then connecting a wiring layer through the conductive material layer.