JPH06104343A - Semiconductor device and manufacture of semiconductor - Google Patents

Abstract

PURPOSE:To prevent the stripping off of a film after patterning by using a high-melting-point metal (such as tungsten) as a wiring material. CONSTITUTION:A high-melting-point metal 3 composed of tungsten is buried in a contact hole 11 formed through a first insulating layer 1 on a semiconductor substrate with a contact layer 2 in between. Then a second insulating layer 4 is formed on the layer 1 and buried tungsten 3. After formation, the layer 4 is flattened by high-temperature heat treatment. In addition, grooves 12 are formed by patterning the layer 4 at locations which become wiring areas. Then tungsten 5 is buried in the grooves 12 formed in the layer 4. After burying the tungsten 5, a third insulating layer 6 is formed on the layer 4 and buried tungsten 5. Therefore, stripping off of films after patterning can be surely prevented.

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 semiconductor manufacturing method, and more particularly to an integrated circuit using tungsten wiring and a manufacturing method thereof.

[0002]

2. Description of the Related Art In a conventional semiconductor device, Al or AlSi is used as a multilayer wiring material. However, in the case of miniaturizing elements in such a semiconductor device, in order to prevent deterioration of reliability due to electromigration, the wiring material must secure a certain cross-sectional area, so that the aspect ratio can be reduced. That is, the thickness of the wiring material cannot be reduced. According to Japanese Patent Application Laid-Open No. 1-135064, a refractory metal material, such as tungsten or molybdenum, which is more resistant to electromigration than Al and has a specific resistance comparable to Al, for reducing the thickness of the wiring material, It is disclosed to be used as a wiring material. In that case, the tungsten layer is formed by a sputtering method or a CVD method,
It is patterned by the photoengraving method. Tungsten has an electromigration resistance that is two or more orders of magnitude higher than that of Al, and has a specific resistance that is slightly less than three times.
If tungsten is used, the thickness of the wiring material can be reduced to less than half that of Al.

[0003]

However, when tungsten is used as the wiring material, a difficult technique is required to process the tungsten, and if the width of the wiring becomes narrow, film peeling may occur after patterning. . Further, when an insulating film layer is formed on the wiring, complicated techniques such as etch back and reflow are required to improve flatness. Therefore, an object of the present invention is to provide a highly reliable semiconductor device which can be manufactured by a simple technique even when a refractory metal is used as a wiring material and can reliably prevent film peeling after patterning. .

[0004]

According to a first aspect of the present invention, a first insulating film layer having a contact hole, which is provided on a semiconductor substrate that constitutes a functional element, is embedded in the contact hole. Refractory metal and the first
A second insulating film layer having a groove formed on the insulating film layer, the wiring region being flattened by high-temperature heat treatment and patterned, a refractory metal embedded in the groove, and the second insulating film. The semiconductor device is provided with a third insulating film layer disposed on the film layer to achieve the above object. Claim 2
In the described invention, in the semiconductor device according to claim 1, the refractory metal is composed of tungsten. Molybdenum may be used as the refractory metal.

According to the third aspect of the invention, in the wiring layer forming step of the integrated circuit, a step of forming a contact hole in the first insulating film layer on the semiconductor substrate forming the functional element, and a step of forming a contact hole in the contact hole are performed. A step of embedding a melting point metal, a step of forming a second insulating film layer on the first insulating film layer, a step of flattening the second insulating film layer by high temperature heat treatment, and a step of forming the second insulating film layer. A step of forming a groove by dry etching in a portion to be a wiring region, a step of embedding a refractory metal in the groove, and a step of forming a third insulating film layer on the second insulating film layer are performed. .

[0006]

[Function] Refractory metals such as tungsten and molybdenum
Since it has a high electromigration resistance and not a relatively high specific resistance, it is clear that this can significantly reduce the thickness of the wiring material. In the present invention, the second insulating film layer is formed after the contact hole is filled and the planarization is performed, so that the planarization process is simple. Since the wiring region is formed by forming a groove in the second insulating film layer and burying tungsten in the second insulating film layer, it is not necessary to process the tungsten by using a particularly complicated technique, and these tungsten films are formed. It does not peel off.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a semiconductor device and a semiconductor manufacturing method according to the present invention will be described in detail below with reference to FIGS. 1 to 7 show a semiconductor device according to the present invention in order according to a manufacturing process thereof.
Is a completed view of the semiconductor device, and its plan view is shown in FIG. In FIG. 1, a first insulating film layer 1 is formed on a semiconductor substrate on which a transistor is formed, and a contact hole 11 is opened at a position of the insulating film layer 1 corresponding to an electrode of the transistor.

Next, as shown in FIG. 2, a refractory metal 3 made of tungsten is buried in the contact hole 11 via the adhesion layer 2. In this case, the filling of the contact hole 11 with the tungsten 3 is performed on the entire surface or by the selective tungsten CVD method. Then, as shown in FIG. 3, a second insulating film layer 4 is formed on the first insulating film layer 1 and the buried tungsten 3. Then, the second insulating film layer is flattened by high temperature heat treatment. Further, as shown in FIG. 4, a groove 12 is formed in the second insulating film layer 4 by patterning and dry etching at a position to be a wiring region.

Next, as shown in FIG. 5, the trench 12 formed in the insulating film layer 4 is again formed by the tungsten CVD method.
Tungsten 5 is embedded. Next, as shown in FIG. 6, on the insulating film layer 4 and the embedded tungsten 5,
Further, the third insulating film layer 6 is formed. After each of the steps described above, as shown in a plan view in FIG. 7, the gate electrode 7 is formed on the third insulating film layer 6, and the semiconductor device according to the present embodiment is completed.

[0010]

According to the present invention, the refractory metal is used as the wiring material, so that the EM and SM resistance is improved. According to the second aspect of the present invention, since the contact hole is filled with the refractory metal, the insulating film layer can be formed after the filling and the heat treatment can be completely planarized. Since the groove is formed in the second insulating film layer and the refractory metal is embedded therein, etching of the metal is unnecessary, the process is simplified, and the film does not peel off. Further, since the width as well as the thickness of the wiring can be reduced by such a method, the degree of integration of the semiconductor device can be significantly increased. Moreover, the reliability of the semiconductor device according to the present invention is high.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a first step of a manufacturing process of a semiconductor device in an example of the present invention.

FIG. 2 is an explanatory view showing the next step in the same as above.

FIG. 3 is an explanatory diagram showing the next step of the same as above.

FIG. 4 is an explanatory view showing the next step in the same as above.

FIG. 5 is an explanatory diagram showing the next step in the same as above.

FIG. 6 is an explanatory diagram showing the next step in the same as above.

FIG. 7 is a plan view showing the last step of the above.

[Explanation of symbols]

 1 First Insulating Film Layer 2 Adhesion Layer 3 Tungsten 4 Second Insulating Film Layer 5 Tungsten 6 Third Insulating Film Layer 7 Gate Electrode

Claims (3)

[Claims] 1. A first insulating film layer having a contact hole, which is provided on a semiconductor substrate constituting a functional element, a refractory metal embedded in the contact hole, and the first insulating film layer. A second insulating film layer having a groove formed by planarizing the wiring region by high-temperature heat treatment and patterning the wiring region, a refractory metal embedded in the groove, and the second insulating film layer. And a third insulating film layer disposed on the semiconductor device. 2. The semiconductor device according to claim 1, wherein the refractory metal is tungsten. 3. A step of forming a contact hole in a first insulating film layer on a semiconductor substrate which constitutes a functional element in a step of forming a wiring layer of an integrated circuit, and a step of burying a refractory metal in these contact holes. A step of forming a second insulating film layer on the first insulating film layer, a step of flattening the second insulating film layer by high temperature heat treatment, and a step of forming a wiring region of the second insulating film layer. A step of forming grooves by dry etching, a step of embedding a refractory metal in these grooves, and a step of forming a third insulating film layer on the second insulating film layer. Manufacturing method of semiconductor device.