JP2845054B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of forming a wiring of a semiconductor device formed on a semiconductor substrate.

[0002]

2. Description of the Related Art Conventionally, in a semiconductor device, as shown in FIG. 3, in order to electrically connect the semiconductor elements, an anti-reflection film of light at the time of patterning an Al thin film having a predetermined film thickness is formed. And a Ti, TiN film for suppressing the reaction between the AlN thin film and the Al thin film and the semiconductor substrate.

A PSG film 4 is patterned on a semiconductor substrate 5, and two layers of a Ti film 1 and a TiN film 2 are brought into contact with the semiconductor substrate 5 through contact holes provided in the PSG film 4. A wiring having a structure is formed (FIG. 3A). Thereafter, a heat treatment is performed in an N ₂ atmosphere (FIG. 3B), an Al—Si—Cu film 6 is deposited (FIG. 3C), and a TiN film 7 is deposited (FIG. 3).
(D)).

Conventional TiN / Al-Si-Cu / TiN
Of TiN / T under Al / Si-Cu film in Ti / Ti film
The i film has been used to suppress the reaction between the Al—Si—Cu film and the semiconductor substrate (contact). Al-
The TiN film on the Si-Cu film is used as an anti-reflection film at the time of patterning the Al-Si-Cu film, and the uppermost TiN film is not heat-treated.

[0005]

In a wiring formed by a conventional method for manufacturing a semiconductor device, the diameter of the Al-Si-Cu film on the side wall due to unreacted Ti in the upper layer of the Al-Si-Cu film is reduced. There is a problem that minute voids of 10 to 100 nm are generated and the reliability of the Al—Si—Cu film as a wiring material is significantly deteriorated.

An object of the present invention is to form a wiring for connecting an integrated circuit element formed on a semiconductor substrate with Ti
It is an object of the present invention to provide a method of manufacturing a semiconductor device capable of suppressing generation of voids on Al-Si-Cu side walls due to unreacted Ti not converted into N.

[0007]

According to a first aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: forming a wiring for connecting an integrated circuit element formed on a semiconductor substrate; Forming a contact hole in the formed insulating film, and forming a two-layer wiring composed of a Ti film as a first layer film and a TiN film as a second layer film so as to be in contact with the semiconductor substrate via the contact hole. And 2
Heat-treating the semiconductor substrate on which the wiring having the layered structure is formed in a nitrogen atmosphere, and forming Al-Si-Cu as the third layer film.
Forming a TiN film as a film and a fourth layer film on the second layer film; and performing a heat treatment in a nitrogen atmosphere on the semiconductor substrate on which the wiring having the four-layer structure is formed.

According to a second aspect of the present invention, there is provided a method of forming a wiring for connecting an integrated circuit element formed on a semiconductor substrate. A step of forming a contact hole, a step of forming a two-layer wiring composed of a Ti film as a first layer film and a TiN film as a second layer film so as to be in contact with the semiconductor substrate via the contact hole; A semiconductor substrate on which a wiring having a structure is formed is subjected to a heat treatment in a nitrogen atmosphere, and a step of forming an Al—Si—Cu film as a third layer and a WSi film as a fourth layer film. You.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG.
4A to 4C are cross-sectional views of a semiconductor substrate shown in a process order for describing a method of manufacturing a semiconductor device according to an embodiment of the present invention.

First, as shown in FIG. 1A, a PSG film 4 is formed on a semiconductor substrate 5 by patterning.
A wiring having a two-layer structure of a Ti film 1 and a TiN film 2 is formed so as to be in contact with the semiconductor substrate 5 via a contact hole provided in the SG film 4.

Thereafter, as shown in FIG. 1B, a heat treatment is performed in an N ₂ atmosphere. Then, as shown in FIG.
An Al—Si—Cu film 6 is deposited. Next, as shown in FIG. 1D, a TiN film 2 is deposited, and then a heat treatment (at 600 ° C. or lower for 30 seconds or more) is performed in an N ₂ atmosphere at a temperature at which Al does not melt.

In the first embodiment described above, after depositing four TiN films, a heat treatment in an N ₂ atmosphere, which has not been conventionally performed, is performed, so that unreacted Ti that has not been completely nitrided is eliminated. Diameter 10-100 by unreacted Ti
There is an effect that a minute void of nm is hardly generated on the side wall of the Al—Si—Cu film 6.

FIG. 2 is a sectional view of a semiconductor substrate shown in the order of steps for explaining a method of manufacturing a semiconductor device according to another embodiment of the present invention. As shown in FIG. 2A, a PSG film 4 is formed on a semiconductor substrate 5 by patterning.
A semiconductor substrate 5 through a contact hole provided in the G film 4
Is formed, a wiring having a two-layer structure of the Ti film 1 and the TiN film 2 is formed. Thereafter, as shown in FIG. 2B, heat treatment is performed in an N ₂ atmosphere. Then Figure 2
As shown in (c), an Al-Si-Cu film 6 is deposited. Next, as shown in FIG. 2D, a WSi film is deposited.

In the second embodiment, since the WSi film is used for the fourth layer, there is an effect that voids due to Ti do not occur on the side wall of the Al—Si—Cu film 6 and an effect that the resistance to Al disappearance is strong. .

[0015]

As described above, according to the present invention, A
Since the upper layer of the l-Si-Cu film is a TiN film or a WSi film that has been heat-treated in an N ₂ atmosphere, voids are generated on the side walls of the Al-Si-Cu due to unreacted Ti not converted to TiN. Is suppressed. In the case of the conventional uppermost layer TiN structure that has not been heat-treated in a N ₂ atmosphere, the void generation rate occurs with a probability of about 50%, but it can be suppressed to 0 by adopting the above structure.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a semiconductor substrate shown in the order of steps for explaining one embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a semiconductor substrate shown in the order of steps for explaining another embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of a semiconductor substrate shown in order of steps for explaining a conventional method of manufacturing a semiconductor device.

[Explanation of symbols]

 Reference Signs List 1 Ti film 2 TiN film 3 WSi film 4 PSG film 5 Semiconductor substrate 6 Al-Si-Cu film

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) H01L 21/28-21/288 H01L 21/3205 H01L 21/3213 H01L 21/44-21/445 H01L 21 / 768 H01L 29/40-29/51 H01L 29/872

Claims (2)

(57) [Claims] 1. A method for forming a wiring for connecting an integrated circuit element formed on a semiconductor substrate, the method comprising: forming a contact hole in an insulating film formed on the semiconductor substrate; A step of forming a wiring having a two-layer structure made of a Ti film as a first layer film and a TiN film as a second layer film so as to be in contact with the substrate; and heat treating the semiconductor substrate on which the wiring of the two layer structure is formed in a nitrogen atmosphere. Forming an Al-Si-Cu film as a third layer film and a TiN film as a fourth layer film on the second layer film, and placing the semiconductor substrate on which the wiring having the four-layer structure is formed in a nitrogen atmosphere. And performing a heat treatment in the semiconductor device. 2. A method for forming a wiring for connecting an integrated circuit element formed on a semiconductor substrate, the method comprising: forming a contact hole in an insulating film formed on the semiconductor substrate; A step of forming a wiring having a two-layer structure made of a Ti film as a first layer film and a TiN film as a second layer film so as to be in contact with the substrate; and heat treating the semiconductor substrate on which the wiring of the two layer structure is formed in a nitrogen atmosphere. And a step of forming an Al—Si—Cu film as a third layer and a WSi film as a fourth layer film.