JP2958716B2 - Integrated circuit wiring structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring structure of an integrated circuit and, more particularly, to an insulating film having a good adhesion between a migration preventing film covering a wiring layer and an insulating film covering the same. This is to prevent peeling.

[0002]

2. Description of the Related Art Conventionally, as a wiring structure of an integrated circuit, FIG.
4 is known. In FIG. 4 , 10
Is a semiconductor substrate such as Si, 12 is an insulating film such as SiO ₂ formed on the substrate 10, and 18 is an insulating film such as SiO ₂ covering the wiring layer on the insulating film 12.

[0003] The wiring structure shown in FIG .
(Aluminum) or Al alloy layer 20
Layer, the surface of layer 20 is made of
By applying the anti-coating film 22 to the layer 20 and the film 2
2 is formed, and an insulating film covering the wiring layer is formed.
18 is formed.

[0004] The wiring layer made of Al or Al alloy is
Technique to prevent migration by applying metal such as W
Surgery is described in the literature (eg, Electronics, February 1990, 26-37).
Page, IEEE, IRPS, 1990, pp. 25-30.
Etc.).

[0005]

[Problems to be solved by the invention] The conventional wiring structure described above
According to the structure, as shown in FIG.
The insulating film 18 that has been in close contact with the solution prevention film 22 is
As shown in Fig. 6, the step sound
S ₁ , S ₂ Etc. from the migration prevention film 22
The gap G is inconvenient to spread around.
You.

The cause of such inconvenience is that the layer 20
Coefficient of thermal expansion between the wiring layer composed of the film 22 and the insulating film 18
Are different from each other and the step sounds S ₁ , S _2, etc.
Cal vapor deposition)
It is considered that stress is concentrated on the insulating film 18.
available.

An object of the present invention is to prevent migration.
New integrated circuit layout that prevents insulation film from peeling from film
It is to provide a line structure.

[0008]

[Means for Solving the Problems] This invention relates to aluminum
Side and above the wiring layer made of aluminum or aluminum
Forming an anti-migration film covering the surface and
So as to cover the wiring layer via a migration prevention film.
In the wiring structure of an integrated circuit formed by forming an insulating film on the
Between the migration preventing film and the insulating film;
Cover both sides and top surface of migration prevention film
A coating is interposed, and the coating is
Adhesion to the insulation film
And the adhesion to the insulating film is
The adhesion of the anti-migration film to the insulating film
It is characterized by the use of
You.

[0009]

[Action] According to the configuration of the present invention, the mig covering the wiring layer
Insulation film between the insulation prevention film and the overlying insulation film
Since a coating with good adhesiveness for writing is interposed, heat stress
The insulation film is separated from the migration prevention film by
Can be prevented. In this way, the insulation film is removed
In order to prevent this, the insulating film must be peeled off from the coating.
Film comes off the anti-migration film before
It is not surprising that the
Even if the adhesion to the migration prevention film is an insulating film
It is necessary to use a material that has better adhesion to
You.

[0010]

【Example】 1 and 2 show one embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line II-II of FIG.
Is shown.

The surface of a semiconductor substrate 10 made of, for example, Si
An insulating film 12 such as SiO ₂ is formed by a known method.
The insulating film 12 is formed by photolithography.
A contact hole 12A corresponding to a part of the substrate surface is formed.
Is done.

On the insulating film 12, a contact hole 12A
Al or so as to make ohmic contact with the substrate surface through
Al alloy (Al-Si, Al-Cu, Al-Si-Cu
) Layer 24 is formed by a sputtering method, a CVD method, or the like.
You. Then, the Al or Al alloy layer 24 is photolithographed.
Patterning according to the desired wiring pattern
As a result, a wiring layer including the remaining portion of the layer 24 is formed.
It is.

On the wiring layer comprising the remaining portion of the layer 24,
For example, a W film is a wiring layer as the migration prevention film 26.
To cover both sides and top surface of
For example, a WSi ₂ film is coated as a film 28 having good adhesion.
The film 28 is applied so as to cover both side surfaces and the upper surface. W film
And the WSi ₂ film are deposited by sputtering or CVD.
Can be used, no need for any film after deposition
Parts are removed to indicate Suyo sectional structure in FIG. this
Then, the wiring formed of the remaining portion of the layer 24 via the films 26 and 28
On the upper surface of the substrate so as to cover the layers such as SiO ₂ or _Si 3 _{N 4}
An insulating film 18 is formed.

[0014] According to the wiring structure described above, from the WSi ₂
The film 28 made of W is more to the insulating film 18 than the film 26 made of W.
Because of good adhesion, even if thermal stress is applied,
The insulating film 18 hardly peels off at the difference portions S ₁ , S _{2 and the} like.
It becomes.

FIG . 3 shows the structure of FIGS. 1 and 2 in a three-layer wiring structure.
Another example applied to (generally multilayer wiring structure)
It is something. The wiring structure of FIG. 3 is as follows as an example.
Can be manufactured.

First, an insulating film covering the surface of the semiconductor substrate 10
12 and Al or Al alloy as described in FIG.
Layer 24 (1) and W migration prevention film 2
6 (1) and coating film 28 of WSi ₂ with good adhesion
(1) is formed as a first wiring layer. And
Is the interlayer insulating film 18 formed to cover the first wiring layer?
A connection hole corresponding to a part of the first wiring layer is formed in the insulating film 18.
To form

Next, a first wiring layer is formed on the insulating film 18.
Similarly, the wiring material layer 24 (2) and the migration prevention film
26 (2) and a coating 28 (2) having good adhesion.
A second wiring layer is formed. In this case, the second wiring layer
Means that a part of the wiring material layer 24 (2) forms a connection hole of the insulating film 18.
Connected to a part of the film 28 (1) of the first layer
It is formed as follows. Then, covering the second wiring layer,
After forming the insulating film 19, the second wiring layer
A connection hole corresponding to a part of is formed.

Thereafter , the wiring material layer is formed in the same manner as the first wiring layer.
24 (3), a migration prevention film 26 (3),
A third wiring layer having a film 28 (3) having good adhesion
Form. In this case, the third wiring layer is the wiring material layer 24.
Part of (3) is a second layer wiring through the connection hole of the insulating film 19.
It is formed so as to be connected to the layer film 28 (2). After this
Forms a protective insulating film 21 covering the third wiring layer.
You.

Note that an insulating film (silicon oxide film, silicon
Materials with low adhesion to recon nitride film, organic film, etc.)
In addition to the above-mentioned W, refractory metals such as Mo, C
u, TiN and the like. In addition, as a material with good adhesion
Is MoSi ₂ , TiSi _{2 in} addition to WSi ₂ described above.
And highly reactive gold such as Al, Cr and Ti
There is a genus. Therefore, the present invention is limited to the above-described embodiment.
It is not something that is combined,
Is also feasible.

[0020]

【The invention's effect】 As described above, according to the present invention, the wiring
Anti-migration film covering the layer and insulating film covering it
Insulation by interposing a film with good adhesion to the insulation film
Prevention of peeling of the membrane ensures reliable collection.
The effect of realizing an integrated circuit is obtained.

Further , the migration preventing film is
Migrate with good adhesion coating while covering both sides and top surface
To cover both sides and top surface
In addition, the effect of preventing migration is improved and the insulating film
Improved peeling prevention effect, especially hillocks on the side of the wiring layer
There is also an advantage that generation can be suppressed.

[Brief description of the drawings]

1 is a cross-sectional view showing a wiring structure according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a sectional view showing another embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a conventional wiring structure.

FIG. 5 shows a contact sound in the wiring structure of FIG. 4;
It is sectional drawing.

FIG. 6 is a view showing the peeling of the insulating film in the vicinity of the contact portion in FIG.
FIG.

[Explanation of symbols]

10: semiconductor substrate, 12, 18, 19, 21 ... insulating film,
24, 24 (1) ... Al or Al alloy layer, 24 (2),
24 (3) ... wiring material layer, 26, 26 (1) to 26 (3)
... Migration prevention film, 28, 28 (1) to 28
(3) A film with good adhesion .

Claims (1)

(57) [Claims] 1. From aluminum or aluminum alloy
Migration on both sides and top surface of wiring layer
Forming an anti-migration film and interposing the anti-migration film
Forming an insulating film so as to cover the wiring layer
Circuit wiring structure, wherein the migration preventing film and the insulating film between the
Cover both sides and top surface of migration prevention film
A coating is interposed, and the coating is
Adhesion to the insulation film
And the adhesion to the insulating film is
A wiring structure for an integrated circuit, wherein a material having better adhesion than the migration preventing film to an insulating film is used.