JPS60117771A - Semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a wiring structure, which prevents the ohmic contact fault of Al wiring or Al alloy wiring, by providing a dummy contact electrode, which has a larger connecting area than the connecting area of the electrodes of an element in the vicinity of the element electrode in the Al wiring and the like, which are extracted from the element electrode. CONSTITUTION:An N<+> type region 2 as a resistor element is provided in a P type silicon substrate 1. Al-Si alloy wirings 3 and 14 are extracted from the N<+> type region through connecting electrodes 2D and connected to a power source V. The Al-Si alloy wiring 14, whose wiring layer is longer, is contacted with an electric insulating region, i.e., an N<+> type region 12, which is provided in the surface of the Si substrate and extracted. In this structure, the area of the N<+> type region 12 provided in the vicinity of the contact electrode and a contact electrode 14D (dummy contact electrode) with the Al-Si alloy wiring 14 is made sufficiently larger than the area of the contact electrodes 2D. Then, the epitaxial growth in the connecting electrodes 2D is remarkably suppressed, and the poor contact is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a semiconductor device, and more particularly to an improved structure of a wiring layer made of aluminum or an aluminum alloy extending over the top surface.

fbl Prior Art and Problems As is well known, in semiconductor devices such as semiconductor integrated circuits (ICs), semiconductor elements and other elements are formed on the surface of a semiconductor substrate, and the wiring derived from these is made of aluminum (A
I) or aluminum alloys are used. Although it is called an aluminum alloy, it is mainly made of aluminum containing only a few percent (10% or less) of other metals.The reason why aluminum is used for wiring is that it has a low electrical resistance and is suitable for insulating films. This is because it has strong adhesive strength, is inexpensive, and is easy to form.

However, there is a problem in that aluminum reacts with the silicon substrate it is in contact with due to heat treatment during the manufacturing process or temperature increase during use, and a silicon epitaxial layer is epitaxially grown on the contact surface. In particular, in the case of aluminum-silicon alloys, epitaxial growth occurs significantly,
This is thought to occur because silicon contained in aluminum serves as a nucleus for growth. However, the detailed mechanism is generally not clear. In addition, epitaxial growth is not limited to aluminum silicon alloys.
It is also seen in pure aluminum wiring.

Incidentally, the epitaxial growth layer grown in this manner becomes a silicon layer with properties different from those of the original silicon substrate, resulting in increased contact resistance and contact failure. FIG. 1 shows a cross-sectional view of a conventional example, in which 1 is a P-type silicon substrate, 2 is an N+ type region 3, 4 is an aluminum-silicon alloy wiring, and 5 is an epitaxial growth layer that becomes a contact barrier. In this example, P-type epitaxial growth N containing aluminum is connected to the power supply V and is connected to the contact portion of the aluminum-silicon alloy wiring 4 on the side where the wiring layer is long.
5 has grown significantly. In this case, a PN junction is formed due to the contact of the N+ type region 2, so that the contact resistance becomes particularly large.

Formation of such an epitaxial growth layer not only increases the contact resistance but also deteriorates the characteristics of the semiconductor element. For example, it is also known to degrade the emitter voltage of bipolar transistors.

Therefore, countermeasures against this problem have been considered and, for example, a method has been proposed in which a film of another material (such as a high melting point metal nitride film) is interposed as a barrier layer on the contact surface. However, since the barrier layer does not have a low resistance like an aluminum film, the contact resistance increases to some extent, which is by no means preferable.

(C) Object of the Invention The present invention proposes a novel wiring structure that prevents such ohmic contact failures in wiring made of aluminum or aluminum alloy films.

(d) Structure of the Invention The object of the invention is to extend the aluminum wiring or aluminum alloy wiring led out from the element electrode by providing a dummy contact electrode having a larger connection area than the connection area of the element electrode near the element electrode. This is achieved by existing semiconductor devices.

te) Examples of the invention Examples will be described in detail below with reference to two drawings.

FIG. 2 shows a plan view of an embodiment according to the present invention, and FIG.
The figure is a sectional view taken along line AA in the figure. In the figure, an N+ type region 2 as a resistance element is provided on a P type silicon substrate 1, and an aluminum silicon alloy wiring 3.14 is led out from this N+ type region through a connection electrode 2D.
The aluminum-silicon alloy wiring 14 connected to the power source (1) and having a longer wiring layer is led out in contact with an electrically insulating region, that is, an N+ type region 12 provided on the silicon substrate surface. Note that 10 indicates an insulating film made of a silicon dioxide film, and the wiring layer has a width of about 2 μm and a thickness of about 1 μm.
The connection electrode 2D of the N+ type region 2 has a diameter of 1.5 μm.

With this structure, if the area of the contact electrode 14D (dummy contact electrode) with the N+ type region 12 aluminum silicon alloy wiring 14 provided near the connection electrode is made sufficiently larger than the area of the connection electrode 2D, the connection electrode Epitaxial growth in 2D is significantly suppressed and contact failure failures are prevented.

The above is an example of an aluminum-silicon alloy wiring layer connecting the N+ type region to the power supply (2), but other experimental results show that not only the wiring connecting the N+ type region or the wiring connecting to the power supply Normal wiring, especially long wiring length (contact failure also occurs in the wiring to be derived,
It has been found that the same effect can be obtained by applying the present invention in that case as well.

ff) Effects of the Invention As is clear from the above description, according to the present invention, wiring made of aluminum or aluminum-silicon alloy can be used in semiconductor devices from contact failure without providing a barrier layer, or in other words, without increasing contact resistance. Since it is possible to protect the semiconductor device, a highly reliable and high-performance semiconductor device can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a structural sectional view of a conventional example, FIG. 2 is a plan view of an embodiment according to the present invention, and FIG. 3 is a sectional view along line AA of the same figure. In the figure, 1 is a P-type silicon substrate, 2 is an N+ type region resistance element), 3, 4.14 is an aluminum silicon alloy wiring,
5 is an epitaxial growth layer that becomes a contact obstacle; 10
is an insulating film, 12 is an electrically insulating region (N+ type region, 2D
indicates a connection electrode, and 14D indicates a dummy contact electrode with the wiring 14.

Claims (1)

[Claims] A semiconductor device characterized in that an aluminum wiring or an aluminum alloy wiring led out from an element electrode extends near the element electrode with a dummy contact electrode having a connection area larger than the connection area of the element electrode.