JPH05121727A - Semiconductor device and manufacturing method thereof - Google Patents

Abstract

PURPOSE:To provide the contact-structure and manufacturing method thereof in simple manufacturing steps and at low resistance even if a semiconductor element is miniaturized. CONSTITUTION:A wiring structure is downward composed of an aluminum base wiring material film 108, an aluminum silicon alloy 107 and a barrier film 104 while the contact part is filled up with the aluminum-silicon alloy film 107. Firstly, polycrystalline silicon is buried in a contact hole and then an aluminum film is formed and heat-treated at 400 deg.C-500 deg.C to be alloyed for the formation of this aluminum-silicon alloy film 107. Through these procedures, the heat treatment at high temperature can be eliminated to mitigate the effect thereof on an element such as transistor, etc., in comparison with the case of filling up the contact hole with the polycrystalline silicon thereby enabling the buried-in contact using a barrier metal to be formed due to the applicable heat-treatment at lower temperature so that the element even if miniaturized may be manufactured in simple steps at low resistance.

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 more particularly to a structure of a wiring joint and a manufacturing method thereof.

[0002]

2. Description of the Related Art A conventional interconnection between wirings of a semiconductor device has a structure and a manufacturing method as shown in FIG. That is, as shown in FIG. 4 (a), a contact hole 3A is formed in the interlayer insulating film 3 on the diffusion layer 2 on one main surface portion of the semiconductor substrate 1, and then as shown in FIG. 4 (b). , Polycrystalline silicon film 5
Is formed by a CVD method to fill the contact hole 3A, and then, when the diffusion layer 2 is, for example, an N type, phosphorus is thermally diffused into the polycrystalline silicon film 4 at a temperature of about 900 ° C. or by ion implantation. , Phosphorus after injection, 800 ℃ ~ 90
Conductivity is imparted by a method such as heat treatment at a temperature of 0 ° C., and then the polycrystalline silicon film 5 is entirely etched as shown in FIG. 4C to leave the polycrystalline silicon only in the contact holes. As shown in FIG. 4D, the aluminum film 6 was formed by the sputtering method.

[0003]

This conventional structure and manufacturing method for the interconnection between wirings of a semiconductor device requires a heat treatment at 800 ° C. to 900 ° C. in order to impart conductivity to the polycrystalline silicon. Not only has an adverse effect on the miniaturization of elements such as transistors, but also makes it difficult to use a barrier metal film (which reacts with silicon in the above heat treatment) in the contact portion, which causes problems such as variations in contact resistance. However, there is a problem that it is disadvantageous in miniaturization of contacts.

[0004]

The semiconductor device of the present invention comprises:
An insulating film that covers a predetermined conductive region of a semiconductor chip, a contact hole formed on the conductive region of the insulating film, and a contact hole portion that contacts the conductive region and is deposited on the insulating film. A barrier metal film, and an upper layer wiring composed of an aluminum-silicon alloy film formed by burying the contact hole via the barrier metal film and an aluminum-based wiring material film coating the aluminum-silicon alloy film. It is a thing.

Further, the method of manufacturing a semiconductor device of the present invention comprises the steps of covering the surface of a semiconductor chip having a conductive region with an insulating film, forming a contact hole on the conductive region of the insulating film, Forming a barrier metal film in contact with the conductive region in the contact hole portion, depositing a polycrystalline silicon film filling the contact hole through the barrier metal film, and forming an aluminum film on the polycrystalline silicon film. A step of depositing, a heat treatment step of reacting the polycrystalline silicon film and the aluminum film to convert into an aluminum-silicon alloy film, and a step of depositing an aluminum-based wiring material film on the aluminum-silicon alloy film. Patterning the aluminum-based wiring material film and the aluminum-silicon alloy film to form an upper wiring. It is intended to refer.

[0006]

The present invention will be described below with reference to the drawings.

1A to 1C and 2A,
(B) is a process order cross-sectional view for explaining one embodiment of the present invention along with its manufacturing process.

First, as shown in FIG. 1A, an interlayer insulating film 103 on a diffusion layer 102 (conductive area) formed on a semiconductor substrate 101 (a gate oxide film on the surface of the semiconductor substrate) may be provided. 0.5 .mu.m.times.0.5 .mu.m contact holes 103A are formed in the above.
A two-layer structure of nm is formed by the sputtering method.

Next, as shown in FIG. 1B, a polycrystalline silicon film 105 having a thickness of about 300 nm is formed by a CVD method to fill the contact hole 103A.

Next, as shown in FIG. 1C, an aluminum film 103 having a thickness of about 100 nm is formed. Next, heat treatment at a temperature of 400 ° C. to 500 ° C. is performed in a hydrogen atmosphere for about 30 minutes to react the polycrystalline silicon film 105 with the first aluminum film 106, and as shown in FIG. -Convert to the silicon alloy film 107. This heat treatment in a hydrogen atmosphere also serves as hydrogen annealing that is usually performed after the formation of aluminum wiring for stabilizing transistor elements and the like.

Next, as shown in FIG. 2 (b), Al-1%
An aluminum-based wiring material film 108 made of Si-0.5% Cu is formed by a sputtering method to have a thickness of about 400 nm. Next, the aluminum-based wiring material film 108, the aluminum-silicon alloy film 107, and the barrier metal film 10
The structure of the semiconductor device of the present invention is obtained by patterning the three-layer film of No. 4 by the photolithography method and the dry etching method to form the upper wiring. Since the barrier metal film is used in the contact portion, a good contact with less variation can be realized. Further, since it is not necessary to introduce impurities to form contacts, it is not necessary to expose the semiconductor chip to high temperature after forming elements such as transistors, so that miniaturization is facilitated.

3A to 3C are sectional views in order of steps for explaining the second embodiment of the present invention along with the manufacturing steps.

Similar to the first embodiment, after the polycrystalline silicon film 105 is formed as shown in FIG. 1B, the entire surface is etched to form the polycrystalline silicon film as shown in FIG. 3A. 205 is left only in the contact hole.

Next, an aluminum film 206 is formed as shown in FIG. 3 (b), and the same heat treatment as in the first embodiment is performed, so that the contact hole and its vicinity are formed as shown in FIG. 3 (c). Then, an aluminum-silicon alloy film 207 is formed thereon, and then an aluminum-based wiring material film 208 is formed in the same manner as in the first embodiment and patterned to form an upper wiring.

In the case of the second embodiment, it is necessary to add an entire surface etching step, but since the thickness of the wiring layer in the vertical direction can be formed thin, it is further advantageous for miniaturization.

Although the case where the conductive region is the diffusion layer has been described above, it will be apparent to those skilled in the art that the present invention can be applied to the contact portion between the lower layer wiring and the upper layer wiring.

[0017]

As described above, according to the present invention, the contact hole is filled with the aluminum-silicon alloy film. In order to realize this structure, the contact hole is first filled with polycrystalline silicon, and then the contact hole is filled with polycrystalline silicon. Since an aluminum film is formed and a heat treatment is performed at a low temperature (400 ° C. to 500 ° C.), it is necessary to give conductivity to the polycrystalline silicon film when the contact is filled with the conventional polycrystalline silicon film. High temperature (800 ℃ -900
The heat treatment at (.degree. C.) is not necessary, the adverse effect on elements such as transistors is eliminated, and it is possible to use a weak barrier metal film for heat treatment at high temperature. Due to the low resistance of the aluminum-silicon alloy and the effect of the barrier metal film, a contact with low resistance can be realized even if the contact size is reduced. In addition, when the heat treatment for alloying aluminum and silicon is performed in a hydrogen atmosphere, it is possible to also serve as a normal hydrogen anneal, so that there is an effect that the manufacturing process can be further simplified.

[Brief description of drawings]

FIG. 1A is a view for explaining the first embodiment of the present invention.
FIG. 4C is a sectional view in order of the processes, which is divided into FIGS.

2A to 2C are cross-sectional views in order of the processes, which are divided into (a) and (b) for explaining the first embodiment.

3A to 3C are cross-sectional views in order of the processes, which are divided into (a) to (c) for describing the second embodiment.

4A to 4D are cross-sectional views in order of the processes, which are divided into (a) to (d) for describing a conventional example.

[Explanation of symbols]

 1, 101, 201 Semiconductor substrate 2, 102, 202 Diffusion layer 3, 103, 203 Interlayer insulating film 3A, 103A Contact hole 104, 204 Barrier metal film 5, 105, 205 Polycrystalline silicon film 6, 106, 306, 406 Aluminum Film 107,207 Aluminum-silicon alloy film 108,208 Aluminum-based wiring material film

Claims (2)

[Claims] 1. An insulating film covering a predetermined conductive region of a semiconductor chip, a contact hole opened on the conductive region of the insulating film, and the insulating film contacting the conductive region at the contact hole portion. An upper layer wiring composed of a barrier metal film deposited on the substrate, an aluminum-silicon alloy film formed by embedding the contact hole through the barrier metal film, and an aluminum-based wiring material film covering the aluminum-silicon alloy film. And a semiconductor device. 2. A step of coating a surface of a semiconductor chip having a conductive region with an insulating film, a step of forming a contact hole on the conductive region of the insulating film, and a step of contacting the conductive region at the contact hole portion. A step of forming a barrier metal film, a step of depositing a polycrystalline silicon film filling the contact hole with the barrier metal film interposed therebetween, a step of depositing an aluminum film on the polycrystalline silicon film, and a step of depositing the polycrystalline silicon film. A heat treatment step of reacting a film with the aluminum film to convert it into an aluminum-silicon alloy film; a step of depositing an aluminum-based wiring material film on the aluminum-silicon alloy film; the aluminum-based wiring material film and the aluminum A method for manufacturing a semiconductor device, characterized by patterning a silicon alloy film to form an upper wiring .