JPH04206528A - Wiring structure in semiconductor device - Google Patents

Abstract

PURPOSE:To avoid the migration in an Al wiring by a method wherein slit parts are formed at specific intervals in the traversing direction of the wiring comprising Al or Al alloy film and then other metallic regions connecting the wirings are provided. CONSTITUTION:Connecting holes 10 are made in an insulating film 3 on an Si substrate 5 and then a barreir metal (W) thin film 4 is formed on the whole surface so as to avoid the reaction produced in the contact part between Si and Al. Next, an Al thin film 6 is formed on the barrier metal (W) 4. Next, a part of the Al film 6 is formed into a pattern and then the Al excluding the wiring part 1 is removed simultaneously to form slit parts 8 at specific intervals in the traversing direction of the wiring part. Next, a W thin film 7 is deposited on the whole surface of the wiring to fill up the slit parts 8 with W. Finally, the whole W on the parts excluding the slit parts 8 is removed to complete the title wiring structure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present Q relates to a wiring structure in a semiconductor device whose wiring material is A12 (aluminum) or an alloy whose main component is Ae.

[Conventional technology]

Miniaturized Al used in circuit wiring of semiconductor devices
In wiring, migration of Al has become a problem.

Al migration is A7! This is a phenomenon in which when a strong current is passed through a wiring, Aβ atoms are moved by the current and move along the grain boundaries, resulting in /l disconnection, which is particularly likely to occur in finer wiring structures.

As a countermeasure against migration in Aβ wiring, as described from pages 85 to 100 of the December 1986 issue of Nikkei Microdevice, other impurities such as Cu (w4) are added to /l. That's AI! Techniques for suppressing wiring migration are known.

[Problem to be solved by the invention]

In the conventional technology described above, when a CVD method is adopted to form Aelm using a gas phase chemical reaction to form A6 wiring, it is practically difficult to form a thin film such as Az and simultaneously add other metals as impurities. There is a problem that sufficient consideration has not been given to this point, and this may impede the application of Attll [forming technology by CVD method as is] to the manufacture of semiconductor devices.

The present invention has been made to solve the above-mentioned problems, and its purpose is to provide a wiring structure that can prevent migration in the Aj2 wiring, and another purpose is to provide a wiring structure that can prevent migration in the Aj2 wiring. The object of the present invention is to provide a two-way wiring technology that does not cause defects due to migration, regardless of the presence or absence of migration.

Still another object of the present invention is to use A7! which does not contain any other metal as a means for forming the AZ wiring having the above structure. aII1%
The method consists in applying the CVD method to form i.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a semiconductor device having wiring formed on a substrate with a film of aluminum or an alloy mainly composed of aluminum, in which the wiring is divided into a plurality of wires at a certain interval in a direction transverse to the wiring. The device is characterized in that it has the slit and is provided with a region made of a metal other than aluminum that electrically connects the divided wiring.

In the wiring structure of the semiconductor device according to the present invention, the region of metal other than aluminum is formed so as to fill the slit.

The present invention also provides that, in the wiring structure of the semiconductor device, the metal region other than aluminum is formed so as to wrap around the upper surface or both upper and lower surfaces of the divided wiring and to electrically connect adjacent divided wiring to each other. It is something that will be done.

Further, in the wiring structure of the semiconductor device, the region of metal other than aluminum is a continuous conductive film formed under the wiring.

[Effect]

A#lii: A of the wire When atoms move along grain boundaries due to electric current, the direction of movement is mainly in the direction of the current, that is, in the length direction of the wiring. On the other hand, the 7111J wiring is
AI! When the wiring is covered with a passivation film that exerts stress, the direction in which Al atoms tend to move is the longitudinal direction of the wiring, which is a direction in which stress is relatively small.

In the present invention, a region in which a slit or a metal other than AI is arranged in a direction across the A6 wiring serves as a barrier to suppress movement of the AJ ring atoms in the length direction. That is, the range in which the A/atom can move is also limited in the length direction. Furthermore, by reducing the distance between this barrier and increasing the area where Al atoms can move,
By narrowing the area where the migrated atoms can be compensated for by elastic deformation of /l, migration within the AN wiring becomes less likely to occur, resulting in disconnection or local thinning. to prevent

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

The first figure is A7 according to the present invention! It is a plan view of the wiring structure and corresponds to FIG. 2(e). The A/wiring 1 is on the base 3 of the insulating film shaped on the Si substrate 5, and this AI! A slit-shaped W (tungsten) region 2 is arranged so as to cross the wiring.

The interval d between the slit W regions is made as narrow as possible within a range that allows for an increase in wiring resistance.

For example, when the thickness C of the Ai wiring l is 0.5 μm and the width of the wiring is 0.5 to 1.0 μm, the slot-to-nod spacing a
is 5 to IO μm, and the slit width d is 0.1 to 0.3 μm.

FIGS. 2(a) to 2(d) are longitudinal sectional views showing a process flow for forming the above wiring structure.

(a) A connection hole 10 is opened in the insulating film on the Si substrate 5, and Si and Ai! A barrier metal (W) aill*4 is formed on the entire surface to prevent a reaction occurring at the contact portion.

(b) Form ANIIv#6 on this (7) to a required thickness by CVD.

(c) Next, A 7! A part of Il*6 is patterned to remove Al other than the wiring portion, and at the same time, slit portions 8 are formed at certain intervals in the direction that crosses the wiring in the portion that will become the wiring.

(d) Then A! on the wiring! W is deposited over the entire surface by CVD as a barrier against migration, and the slit portion 2 is completely filled with W.

(e) Finally, the entire upper surface is etched and hacked to remove the wy in areas other than the slit portions to complete the wiring structure of the present invention.

In the above structure, the W region 2 arranged in a slit shape has the role of limiting the range in which Al atoms can move in the length direction of the wiring.

In this embodiment, the movement of Al atoms, especially in the wiring direction, is restricted to prevent disconnection or thinning of the A1 wiring due to migration.

Since such effects can be obtained regardless of the presence or absence of other metals in the AI2 wiring, an AJ thin film containing no impurities produced by the CVD method can be used as the wiring. Since the Af thin film described above has excellent step coverage, it is possible to form a highly reliable Al wiring structure without causing connection failures or disconnections even on a base substrate with large steps.

FIGS. 3 to 6 show other embodiments of the present invention in longitudinal cross-sectional views of wiring, respectively.

FIG. 3 shows an example in which Wm9 is formed on a substrate (not shown) by CVD or the like, and Al wiring 6 is formed thereon by CVD.

This Al wiring 6 is provided with slits 8 at appropriate intervals in a direction transverse to it. In this embodiment, a region made of a metal other than A/ is not provided in the slit (although it is possible to do so. However, due to the presence of the slit, migration in the wiring direction does not occur, and on the other hand, the underlying W film 9 prevents A/ The electrical connection of the entire wiring 6 is maintained.
If the slit width d is made extremely narrow, the resistance within the wiring caused by the slit 8 will be small.

FIG. 4 shows an example of a sandwich structure in which a W film 4 is formed by CVD on the upper surface of the AIt wiring 6 shown in FIG. 3, and corresponds to FIG. 2(d).

The effect of migration prevention and the effect of electrical connection of the entire Al wiring in this embodiment are the same as in the example shown in FIG.

FIG. 5 shows a slit-shaped W film in which only a slit is made without providing a W film or the like on the base of the Affi wiring 6 shown in FIG. Set it to area 2, and select Will! on the top surface.
This is an example in which .

In this example, only the metal region 2 embedded in the slit electrically connects the entire AN wiring 6 and has the effect of preventing A1 migration.

FIG. 6 shows W[
This is an example in which i14 is left.

The effects in this case are almost the same as in the example shown in FIG.

What these embodiments have in common is that migration of the AJ wiring is prevented by providing slits in the Al wiring, and WIIij! The electrical connection of the entire A1 wiring is maintained by providing the area, and the form changes depending on the process of forming the W film by the CVD method.

〔Effect of the invention〕

According to the invention, Aj? Regardless of whether or not a metal other than Al is present in the wiring, Al migration can be effectively prevented and the reliability of the Al wiring can be improved.

The present invention is particularly effective in semiconductor devices using fine Al wiring, and AJ using the CVD method that does not contain other metals.
illp can be used.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an AJ wiring structure showing one embodiment of the present invention. FIGS. 2(a) to (e) show two AI systems according to the present invention! , is a cross-sectional view showing a process for creating a wiring structure, especially (
e) The figure is a vertical cross-section of A-A' in Figure 1. 3... base insulating film, 4... barrier metal for preventing Al-Si reaction (
W), 5...Si substrate, 6...A by CVD method
l11l11! (AIl wiring), 7... W thin film by CVD method, Fig. 1 Fig. 2

Claims (1)

[Scope of Claims] 1. In a semiconductor device having a wiring formed of a film of aluminum or an alloy mainly composed of aluminum on a substrate, the wiring has several parts dividing the wiring at a certain interval in a direction transverse to the wiring. 1. A wiring structure in a semiconductor device, comprising a slit and a region made of a metal other than aluminum that electrically connects the divided wirings. 2. In the wiring structure in the semiconductor device according to claim 1, the region of metal other than aluminum is formed so as to fill the slit. 3. In the wiring structure in a semiconductor device according to claim 1, the metal region other than aluminum wraps the upper surface or both upper and lower surfaces of the divided wiring and electrically connects the adjacent divided wiring to each other. It is formed. 4. In the wiring structure in a semiconductor device according to claim 1, the region of metal other than aluminum is a continuous conductive film made of tungsten formed under the wiring.