KR19980056165A - Metal wiring formation method of semiconductor device - Google Patents

Abstract

The present invention provides a method for forming metal wirings of a semiconductor device that can improve the metal wiring reliability of the semiconductor devices.

The present invention includes forming an interlayer insulating film on a semiconductor substrate on which an integrated circuit is formed; Etching the interlayer insulating film to form a contact hole having a wider inlet than a contact; Forming a tungsten plug in a contact portion of the contact hole; And embedding a metal wire in an inlet of the contact hole to be in contact with the tungsten plug.

Description

Metal wiring formation method of semiconductor device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming metal wirings in semiconductor devices, and more particularly, to a method for forming metal wirings in semiconductor devices that can ensure metal wiring reliability.

As semiconductor devices become finer and more highly integrated, the width of the contact hole for contacting the gate electrode or the source and drain diffusion regions of polysilicon with the metal wiring becomes smaller, and the depth of the PN junction of the diffusion regions becomes thinner and thinner. Contact resistance is increased, and a multilayer metal wiring process is required.

Therefore, conventionally, a metal wiring method using a tungsten plug has been proposed in order to easily form metal wiring in minute contact holes.

Herein, a conventional method for forming a contact hole plug will be described with reference to FIG. 1, after the interlayer insulating film 2 is deposited to a predetermined thickness on a semiconductor substrate 1, for example, on a semiconductor substrate 1 on which an integrated circuit is formed. The interlayer insulating film is etched to expose a predetermined portion of the semiconductor substrate, i.e., the conductive region of the semiconductor substrate, to form a contact hole (not shown). After being deposited on the interlayer insulating film 3, the tungsten film is polished by an etch back or chemical mechanical polishing method until the interlayer insulating film 3 is exposed, and embedded in the contact hole, thereby forming a tungsten plug 3. Thereafter, the metal wiring 4 is formed to be in contact with the tungsten plug 3.

However, in the tungsten plug as described above, during the etch back or chemical mechanical polishing process of the tungsten film, tungsten residue remains on the interlayer insulating film, causing a bridge phenomenon.

Accordingly, an object of the present invention is to provide a method for forming a metal wiring of a semiconductor device capable of preventing a bridge phenomenon caused by tungsten waste when forming a tungsten plug film.

1 is a cross-sectional view for explaining a metal wiring formation method of a conventional semiconductor device.

2A to 2E are cross-sectional views of respective manufacturing processes for explaining a method for forming metal wirings of a semiconductor device of the present invention.

* Description of the symbols for the main parts of the drawings *

11 semiconductor substrate 12 interlayer insulating film

13-1, 13-2: mask pattern 14: barrier metal film

15: tungsten film 15A: tungsten plug

16 metal film 16A metal wiring

In order to achieve the above object of the present invention, the present invention comprises the steps of forming an interlayer insulating film on a semiconductor substrate on which an integrated circuit is formed; Etching the interlayer insulating film to form a contact hole having a wider inlet than a contact; Forming a tungsten plug in a contact portion of the contact hole; Embedding a metal wire in an inlet of the contact hole to be in contact with the tungsten plug.

According to the present invention, the contact hole is formed to have a contact portion and an inlet portion having a width greater than that of the contact portion, thereby forming a tungsten plug in the contact portion, and forming an aluminum metal wiring in a form embedded to contact the tungsten plug in the contact portion at the inlet portion. Thus, metal bridge phenomenon of tungsten is prevented, and the surface of the semiconductor substrate is planarized.

EXAMPLE

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2A to 2E are cross-sectional views of respective manufacturing processes for explaining a method for forming metal wirings of a semiconductor device according to the present invention.

First, referring to FIG. 2A, a first interlayer insulating layer 12 is deposited to a predetermined thickness on an integrated circuit, for example, a semiconductor substrate 11 on which a MOS transistor is formed. Subsequently, after the first contact mask pattern 13-1 is formed on the interlayer insulating layer 12 to define the contact hole, the interlayer insulating layer 12 is etched in the form of the first contact mask pattern 13-1. As a result, a first contact hole H1 is formed.

Thereafter, the first contact mask 13-1 is removed by a known method, and as shown in FIG. 2B, the first contact hole H1 and the first contact hole H1 are disposed on the interlayer insulating layer 12. The second contact mask pattern 13-2 is formed to expose the first interlayer insulating layer 12 on both sides. That is, the width exposed by the second contact mask pattern 13-2 is larger than the width of the first contact mask pattern 13-1. Thereafter, the first interlayer insulating layer 12 exposed in the form of the second contact mask pattern 13-2 is etched by a predetermined thickness to form a second contact hole H. Therefore, the width of the contact portion T1 of the second contact hole H2 is smaller than that of the inlet portion T2. It becomes a form.

Thereafter, as shown in FIG. 2C, a barrier metal film 14 having excellent contact characteristics with subsequent metal wirings is formed on the semiconductor substrate 11 formed with the second contact hole H to have a predetermined thickness. Here, the barrier metal film 14 may be formed of a laminated film of a titanium metal film or a titanium metal film titanium nitride film. Subsequently, a tungsten film 15 having a thickness sufficient to embed the lower structure is formed on the barrier metal film 14.

Next, referring to FIG. 2D, the tungsten film 15 is anisotropically etched back to expose the upper portion of the first interlayer insulating film 12, and is buried in the contact portion T1 of the second contact hole H2. At this time, since the tungsten film 15 has a higher etching rate than the barrier metal film 14, the tungsten film 15 may be easily buried only in the contact portion T1. Then, on top of the resultant, a film 16 having excellent conductive properties, such as a metal film, for example, aluminum, is formed so that the lower structure is embedded.

Then, as shown in FIG. 2E, the aluminum film 16 is chemically mechanically polished to expose the surface of the first interlayer insulating film 12, and is embedded in the inlet portion T2 of the second contact hole H2. . Thus, the metal wiring 16A is formed. At this time, since the width of the inlet portion T2 is wider than the width of the contact portion T1, a metal film such as aluminum is easily embedded, and the surface of the semiconductor substrate is flattened. Thereafter, a second interlayer insulating film 17 is formed on the resultant.

As described in detail above, according to the present invention, the contact hole is formed to have a contact portion and an inlet portion having a width greater than that of the contact portion, thereby forming a tungsten plug at the contact portion, and the inlet portion is buried to contact the tungsten plug at the contact portion. Forming aluminum metal wirings in the form prevents the tungsten metal bridge phenomenon, and the semiconductor substrate surface is planarized.

Thus, the reliability of the metal wiring is improved.

Claims (7)

Forming an interlayer insulating film on the semiconductor substrate on which the integrated circuit is formed; Etching the interlayer insulating film to form a contact hole having a wider inlet than a contact; Forming a tungsten plug in a contact portion of the contact hole; And embedding a metal wire in an inlet portion of the contact hole to be in contact with the tungsten plug. The method of claim 1, wherein the forming of the contact hole comprises: forming a first mask pattern on the interlayer insulating layer; Etching the interlayer insulating film in the form of the first mask pattern to form a first hole; Removing the first mask pattern; Forming a second mask pattern to expose the first hole and an upper portion of the interlayer insulating layer adjacent to the first hole; Etching the interlayer insulating layer only by a predetermined depth in the form of the second mask pattern; And removing the second mask pattern. The method of claim 1, wherein the forming of the tungsten plug comprises: forming a barrier metal layer on the semiconductor substrate on which the contact hole is formed; Forming a tungsten film on the barrier metal film; And etching the turnsten film so that the interlayer insulating film is exposed and buried in the bottom of the contact hole. 4. The method of claim 3, wherein the barrier metal film is a titanium film. 4. The method of claim 3, wherein the barrier metal film is a laminated film of a titanium film and a titanium nitride film. The method of claim 1, wherein the forming of the metal line comprises: depositing a metal film on the semiconductor substrate on which the tungsten plug is formed; Chemical mechanical polishing the metal film to expose the interlayer insulating film. 7. The method of claim 6, wherein the metal film is an aluminum film.