JP3158457B2 - Aluminum-based material wiring forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for forming an aluminum-based material wiring. Aluminum-based materials such as aluminum and aluminum alloys are used, for example, for forming wiring of various electronic materials (semiconductor devices, etc.), and the present invention is applied to, for example, formation of aluminum-based material wiring in such fields. It can be used for general purposes.

[0002]

2. Description of the Related Art The trend of miniaturization and miniaturization of electronic materials is
It is becoming more and more prominent. For example, the progress of miniaturization and integration of semiconductor integrated circuits is remarkable. Along with this, miniaturization and lamination of wiring have become essential technologies. However, the miniaturization of the wiring accompanying the high integration causes a decrease in reliability.

[0003]

Problems to be Solved by the Invention Stress migration is a major factor as well as electromigration as a cause of lowering the reliability, and the latter is particularly important in recent years. Stress migration is a phenomenon in which an aluminum-based material portion moves so as to reduce the stress applied to the wiring. In this case, the disconnection is caused by diffusion of an aluminum-based material such as Al due to stress migration.

[0004] The generation mechanism is considered as follows. (1) The passivation film having a compressive stress exerts a tensile stress on the internal aluminum-based material wiring in order to release the stress by bending deformation. The effect of the bending deformation is remarkable when the wiring width is large. (2) Voids (cracks, hollows) in the fine wiring are generated due to a difference in thermal expansion coefficient between the wiring and a silicon substrate or a passivation film on an upper layer of the wiring.

[0005] Therefore, as a method of reducing voids, improvement has been made by reducing the stress of the upper layer film of the aluminum-based material wiring, reducing the forming method, and the like. However, none of them has reached the point where voids are completely suppressed.

[0006]

SUMMARY OF THE INVENTION The invention according to the present application has been made in view of the above-mentioned problems, and is intended to be applied to a stress applied to an aluminum-based material wiring, especially when an upper layer film such as a passivation film is formed on the wiring. It is an object of the present invention to provide a method of dispersing and relaxing the stress applied in the X-axis direction and the Y-axis direction on the wiring formation plane of this film to suppress the stress migration and thereby obtain a highly reliable aluminum-based material wiring. Things.

[0007]

Means for Solving the Problems According to the first aspect of the present invention, at least a semiconductor substrate is made of an aluminum-based material.
Also , when forming the wiring on the active region, at the time of patterning the wiring pattern, while keeping the width of the wiring pattern almost the same, and provided convex portions on both sides of the wiring,
A recess is provided in each opposing portion, and a recess is provided on each side
And the projections are alternately arranged , and the aluminum-based material wiring is
A method for forming an aluminum-based material wiring to be covered with a coating film, wherein the above object is achieved by this configuration.

According to the invention of claim 2 of the present application, when a wiring is formed from an aluminum-based material, a pattern of a wiring pattern is formed.
When turning, keep the width of the wiring pattern
And, on both sides of the wiring, provide projections on both sides,
Put the concave part in each opposing part
And the aluminum-based material wiring is made of Si.
O ₂ or SiN passivation film
An aluminum-based material wiring forming method to be overturned, which achieves the above object by this configuration.

In the invention of the present application, the term “aluminum-based material” means a material containing at least aluminum, such as pure aluminum, an aluminum alloy containing aluminum and other metals, nonmetals, and / or compounds, and other aluminum-containing materials. Say

[0010]

According to the invention of the present application, when patterning an aluminum-based material wiring pattern, the width of the wiring pattern is formed so as to be substantially the same, so that a good wiring having substantially uniform conductivity can be formed. In the present invention,
Providing irregularities in the width direction of the wiring pattern , especially for both wiring
Protrusions are provided so that each opposing part is a recess.
Because of the patterning, the stress can be dispersed and relieved by the unevenness, so that an aluminum-based material wiring with suppressed stress migration can be obtained.

This effect was confirmed by the following experimental results and stains.
This can be supported by the results of the simulation . In general, the voids entering the aluminum-based material wiring depend on the stress of the upper layer film (passivation film and the like) and the wiring width. In particular, the wiring width is considered to give the void generation amount shown in FIG. The relationship between the wiring width is shown in μm on the axis and the bulging amount of the aluminum-based material causing voids is shown in volume% on the axis of ordinate, and the relationship between the two is shown as −1 × 10 ⁹ dyne / cm. ^In the case of ² , I and -3 ×
In the case of 10 ⁹ dyne / cm ² , ^two cases of II were shown). However, in general, when a wiring is formed, the amount of voids a generated in the aluminum-based material wiring (aluminum wiring) 1 increases in the direction along the Y-axis due to the stress in the X-axis direction as shown in FIG. Voids are easy to enter, and it is difficult to enter in the direction along the X-axis where the wiring width extends over several mm. This is considered to be because the bulge of the passivation film or the like, which is the upper layer film of the wiring, takes a complicated shape without simple expansion when the wiring width exceeds a certain wiring width, and as a result, stress is reduced.
That is, as shown in FIG. 7A, when the width of the wiring 1 is narrow, the bulge b which causes the void is generated over the entire width of the wiring, but when the width of the wiring 1 is extremely wide, FIG. As shown in ()), due to the complicated expansion of the upper layer film 2, bulges b that cause voids are scattered, and the generation of voids is suppressed.

For this reason, when the wiring is formed by forming irregularities in the width direction of the wiring pattern as in each invention of the present application, the stress is dispersed, and the generation of voids can be reduced. Further, since each invention has a passivation film as an upper layer, the effect of protecting the wiring is great, and particularly, water (H
_The effect of blocking 2O) is large.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the invention according to the present application will be described below with reference to the drawings. However, needless to say, each invention is not limited by the embodiments described below. Of the following specific examples, Examples-1 and 2 are reference examples.
Embodiment 3 is an embodiment according to the present invention to which the present invention is applied.
It is.

Example 1 (Reference Example) In this example, aluminum (containing about 1% by weight of pure aluminum or Si ) in a semiconductor integrated circuit is used.
Alternatively, a case is shown in which an Al alloy wiring containing a smaller amount of Cu is formed. On this aluminum wiring, a passivation film for protection (SiO ₂ , PS
iN, P-TEOS, or any other passivation material).

In this embodiment, as shown in a perspective view in FIG. 1 and a plan view in a main part in FIG. 2, an aluminum-based material wiring 1 is formed on a substrate 3 such as a semiconductor substrate, particularly on at least an active region thereof. Form. The wiring 1 is patterned such that a convex portion 11 and a concave portion 12 are formed on a plane as shown in the drawing. The wiring width should be kept almost equal.

As a result of this configuration, the stress applied to the wiring 1 is dispersed and reduced by the convex portions 11 and the concave portions 12 by the above-described operation. Therefore, even if an upper layer which is a passivation film is formed on the wiring 1 as in this example, the occurrence of stress migration can be suppressed. As a result, a highly reliable aluminum-based material wiring can be formed.

Embodiment 2 (Reference Example) In this embodiment, as shown in FIG. 3, the protrusions 13 and 15 are formed only on one side of the wiring 1 so that the wiring width of the aluminum-based material wiring 1 is constant. And the opposing part is the recess 1
In this way, the stresses in the X and Y directions are dispersed and relaxed. This embodiment can also achieve the same effects as the first embodiment.

Embodiment 3 ( Embodiment according to the present invention) In this embodiment, as shown in FIG. 4, the protrusions 17 are provided on both of the aluminum-based material wiring 1 so that the wiring width of the wiring 1 is constant. 19, each of which opposes a recess 18,
20 .

According to this embodiment, when the aluminum-based material wiring 1 is patterned, the wiring is provided with a convex portion (recess). Therefore, even when an upper layer is formed on the wiring 1, the upper layer is formed by the upper layer. and stress applied in the longitudinal direction is distributed by the convex portion (concave portion) is reduced voids generated in the wiring 1, is prevented stress migration can form a highly reliable wiring, protrusions especially both wires 1 17 and 19
So that the opposing portions are concave portions 18 and 20, respectively.
With this configuration, this effect is effectively exhibited.

It is needless to say that the specific structure of the present embodiment is not limited to the illustrated one, but can take various forms.

[0021]

According to the invention of the present application, the stress applied to the aluminum-based material wiring is reduced and dispersed. Particularly, even when an upper layer film such as a passivation film is formed on the wiring, the stress applied by the presence of this film is reduced. Are dispersed and alleviated to suppress stress migration, whereby a highly reliable aluminum-based material wiring can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of Example - 1.

FIG. 2 is a plan view of a main part of Example - 1.

FIG. 3 is a plan view of a main part of Example - 2.

FIG. 4 is a plan view of a main part of Example - 3.

FIG. 5 is a diagram illustrating a relationship between a wiring width and void generation.

FIG. 6 is an operation explanatory view.

FIG. 7 is an operation explanatory view.

[Explanation of symbols]

1 Aluminum-based material wiring 17, 19 Wiring projection 18, 20 Wiring recess

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/3205-21/3213 H01L 21/768

Claims (2)

(57) [Claims] 1. A semiconductor substrate made of an aluminum-based material .
When forming a wiring in at least the active region, when the patterning of the wiring pattern, while keeping the width of the wiring pattern substantially the same, and a convex portion provided on both the sides of the wiring, the recesses each facing portion of Set up on each side
Patterning so that the concave portions and the convex portions are alternately arranged , and the aluminum-based material wiring is
A method of forming an aluminum-based material wiring to be covered with a passivation film . 2. A wiring is formed from an aluminum-based material.
When patterning the wiring pattern,
Line widths should be almost the same, and
And both sides are provided with convex portions, and concave portions are
While patterning the aluminum
The nickel-based material wiring is made of SiO ₂ or SiN
A method of forming an aluminum-based material wiring to be covered with a passivation film .