JPS61156837A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the disconnection, shift, and rise of Al wiring layers formed on a TiN film serving as the barrier layer of the titled device by reducing its stress by Ar<+> ion implantation to it. CONSTITUTION:A window is opened at the electrode-forming part of an insulation film 12 on a semiconductor substrate 11, and a silicide layer 13 is formed. Next, in order to increase the overage of the barrier layer, and Al thin layer 14 is formed, and then a TiN film 15 is formed under conditions for enhancing barrier properties. The stress of the TiN film 15 is reduced by Ar<+> ion implantation as shown by arrows. Finally, an Al wiring layer 16 is formed to a desired film thickness. This method prevents the disconnection, positional shift, etc. of Al wirings and improves the IC reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a semiconductor device, and more particularly, the present invention relates to a method for manufacturing a semiconductor device, and more particularly, the present invention relates to a method for manufacturing a semiconductor device, and more specifically, an electrode wiring layer taken out from a surface of a semiconductor substrate is made of titanium nitride (
Aluminum (TiN) barrier layer can be adjusted by adjusting the stress of this barrier layer.
l) Relates to a method for preventing wire breakage.

[Conventional technology]

In the formation of integrated circuits (ICs), a technology that forms active elements on a silicon substrate and provides a wiring layer using AI is often used, but the reason for using Al in particular for the wiring is that it has low resistance. This is because it is easy to process, especially etching and forming fine patterns, has good adhesion, and is inexpensive. Therefore, as shown in the cross-sectional view of FIG. 2, a second layer of Al wiring 24 is formed on the silicon substrate 21, a glabella insulating film 23 is grown on the entire surface, and a window is opened in this glabella insulating film.
Finally, an Al wiring 24 is formed and the entire surface is covered with a cover film 25.

However, it is known that junction breakdown occurs when AI wiring is formed on a silicon substrate. Third
Referring to the cross-sectional view in the figure, after forming a base region 32 on a silicon substrate 31 and an emitter region 33 in the base region, and opening a window in an insulating film 34, A7! A wiring layer 35 is formed. In the IC manufacturing process, generally the A1 wiring layer 35
After forming, heat treatment at 400 to 450° C. is performed 3 to 5 times.

When the heating cycle described above is repeated, the silicon of the silicon substrate is sucked up into the wiring layer, and the AN of the Al wiring layer enters into the silicon substrate. When the portion 35a into which the All metal enters reaches the base region 32 as shown in the figure, a junction breakdown, that is, an emitter-base short occurs.

As the degree of integration of ICs increases and finer patterns are formed, emitter regions and base regions are formed shallower, so the above-mentioned problems tend to further increase.

[Problem that the invention seeks to solve]

Two methods have been proposed to solve the above problem. One of them is A7! This is a method in which about 1 to 2% of silicon is mixed in to prevent silicon from being sucked up. 450℃
The solid solubility of silicon in Al is about 0.7%,
The amount of silicon introduced is increased to the above value. However, although there are no particular problems with this method at the wafer processing stage, there is a problem that silicon precipitates on the wiring at the end of the process or during use of the IC (formation of polysilicon flowers), which increases the resistance of the wiring. .

Furthermore, in recent years, automation of device assembly processes has progressed, and the heat resistance of devices is required to be such that no abnormality occurs even when exposed to a temperature of at least 500° C. Therefore, the applicant has developed a semiconductor device (NPN bipolar semiconductor device) shown in FIG. 4, and in the same figure,
41 is a semiconductor substrate, 42 is an insulating film, 43 is an electrode wiring, 4
4 is a first thin layer, 45 is a second thin layer, and 46 is a third thin layer, and in this semiconductor device, the electrode wiring layer led out from the surface of the semiconductor substrate is made of aluminum, an aluminum alloy, or an aluminum alloy. a first thin layer made of silicide and in ohmic contact with the semiconductor substrate;
Tit W+ formed on a thin layer of Mo, Zr+
Cr+Hr, sb, v, Nt+ Pt+ Ta,
A second material made of one selected from Pd and its alloys.
and a third layer made of aluminum silicide or aluminum alloy silicide formed on the second thin layer.
It is characterized by consisting of a thin layer of.

A second method to solve the above problem is to form titanium or platinum silicide in the contact area with the Al wiring on the substrate, and then apply titanium nitride (TiN) as a barrier layer on top of the titanium or platinum silicide.
) and form an Aj2 wiring on the TiN to form a barrier against silicon wicking. Although this method yields very good results, it has been found that if there are areas where the adhesion and coverage of TiN is poor, silicon wicking occurs throughout the year, causing junction breakdown. Therefore, a solution to this problem is also required in a method using a barrier layer.

By the way, when forming a barrier layer with titanium nitride, the properties of titanium nitride (resistivity, stress, etc.) changes. It was also confirmed that if conditions were set to increase the barrier properties, a highly stressed TiN film would grow.

When an A1 wiring layer is formed on such a TiN film, the T
Since the stress of the iN film is large, there is a problem that the AN wiring layer may be disconnected, shifted, or bulged.

[Means for solving problems]

The present invention provides a semiconductor device that solves the above-mentioned problems, and its means include a method of forming an electrode wiring layer that is taken out from the surface of a semiconductor substrate, and a high melting point metal silicide is applied to the electrode forming portion of the substrate. Forming a thin aluminum layer and a titanium nitride film in order on the silicide layer, ■ Forming a thin aluminum layer and a titanium nitride film in order, ■ Forming a silicide layer of a high melting point metal on the silicide layer. After any one of the steps of forming titanium nitride on the titanium nitride film, the method includes a step of ion-implanting argon into the titanium nitride film, and a step of forming an aluminum wiring layer on the titanium nitride film after the ion implantation. A method for manufacturing a semiconductor device characterized by the following.

[Effect]

In the above method, argon (Ar") is applied to the TiN film.
) is ion-implanted to relieve the stress on the TiN film, thereby preventing disconnection, misalignment, and
This is to prevent swelling.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

First, as shown in FIG. 1 (al), a window is made in the electrode formation portion of the insulating film 12 on the semiconductor substrate 11, and a silicide layer (TiSiz, TaSi2, PtSi2, etc.) 1 of a refractory metal is formed therein.
3 using conventional techniques. Next, in order to increase the coverage of the barrier layer, an AI thin layer 14 is formed to a thickness of 200 nm, and then a TiN film 15 is formed by reactive sputtering.
is formed to a film thickness of 2000 mm under conditions to improve barrier properties. (For example, N2 ratio 50%, sputtering pressure 10-' To
rr, sputter power 3KW, substrate bias 150V)
.

Then Ar” was accelerated to 70 eV with an acceleration energy of 2×10
Ions are implanted at a dose of 1'I/cm2 as shown by the arrow in the figure to relieve the stress on the TiN film 15, and then the surface of the TiN film is cleaned by ion implantation by sputter etching.

Finally, as shown in FIG. 1(b), the Al wiring layer 16
is formed to a desired thickness (generally 1000 Å or more).

〔Effect of the invention〕

As explained above, according to the present invention, T
By ion-implanting Ar+ into the iN film, the stress is alleviated, so no stress is applied to the Al wiring formed on it, which prevents disconnection and misalignment of the Al wiring, improving IC reliability. It is highly effective.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are sectional views of the electrode forming portion at the stage of carrying out the method of the present invention, and FIGS. 2, 3, and 4 are sectional views of the conventional example. In the figure, 11 is a semiconductor substrate, 12 is an insulating film, 13 is a silicide layer, 14 is AltWIN, 15 is TiN n'J
I, 16 ha Aj? The wiring layers are shown respectively. (Q) (b) Figure 1 Figure 2 Figure 3 WJ *Figure 4'

Claims (1)

[Claims] A method of forming an electrode wiring layer that is taken out from the surface of a semiconductor substrate, (1) forming a silicide layer of a high melting point metal on the electrode forming part of the substrate, and sequentially forming a thin aluminum layer and a titanium nitride film on the silicide layer. The process of (2
) The step of sequentially forming an aluminum thin layer and a titanium nitride film, and (3) the step of forming a silicide layer of a high melting point metal and forming titanium nitride on the silicide layer. 1. A method for manufacturing a semiconductor device, comprising the steps of ion-implanting argon into the film, and forming an aluminum wiring layer on the titanium nitride film after the ion implantation.