JPH0126533B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrode structure of a semiconductor device, and more particularly to a structure of a bonding pad on a pellet side for connecting an external terminal and a pellet with a metal wire.

Conventionally, a pellet bonding pad is made of an oxide film 2 formed on a substrate 1, as shown in FIG.
On top of this, an aluminum wiring 3 and an aluminum electrode 4 continuous thereto are simultaneously formed, insulators 5, 5', etc. are formed as passivation, and the aluminum electrode 4 is exposed and used as a bonding pad. Alternatively, a metal wire 6 such as a gold wire is used to perform bonding to establish a connection with an external terminal. In the case of this structure, the moisture remains on the pellet for a long period of time (for example, several thousand
As the bonding pad around the metal wire 6 is exposed to light, aluminum has a large ionization coefficient, and as a result, it dissolves into moisture as Al ³⁺ ions, and the aluminum electrode 4 in this area dissolves into the moisture. In some cases, holes as shown at 7 and 7' in FIG. 2b were formed in the aluminum electrode 4 and the aluminum wiring 3 became electrically open.

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor device having a structure that prevents disconnection between a bonding pad and a wiring connected thereto due to moisture infiltrating from an exposed portion of the bonding pad. The semiconductor device of the present invention includes a first insulating film provided on a semiconductor substrate, an electrode portion provided on the first insulating film, and a wiring portion continuously led out to a part of the electrode portion. and a second insulating film that covers the first insulating film and the metal layer, and an opening provided in the second insulating film allows the electrode portion of the metal layer to be In a semiconductor device in which a portion of the electrode portion is exposed and the exposed portion is used as a bonding pad, a low resistivity polycrystal doped with an impurity is provided between the bonding pad portion of the electrode portion and the first insulating film. A silicon layer is provided in contact with the bonding pad portion, and the polycrystalline silicon layer is formed to extend toward the wiring portion through a portion of the metal layer covered with the second insulating film. The wire is electrically connected to the wiring portion.

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

As shown in FIG. 2a, on the oxide film 2 formed on the substrate 1, a polycrystalline silicon 8 doped with impurities and having a low resistivity of about 5000 Å is formed, and an aluminum wiring 3 and an aluminum electrode 4 are formed on the oxide film 2. Continuously form about 2 μm at the same time. Thereafter, insulators 5 and 5' are formed as passivations. Polycrystalline silicon 8, aluminum electrode 4, and aluminum wiring 3 must be electrically connected.

In the case of the above structure, holes 7 and 7' are formed as shown in Figure 2b, similar to the conventional structure, so that the state of use for a long time can be read with moisture attached to the beret. Even if there is a disconnection between the aluminum electrode 4 and the aluminum wiring 3, the conductive path is formed through polycrystalline silicon, and this polycrystalline silicon does not dissolve in moisture. No holes will be made beyond the point. Therefore,
Electrical connection is made through the route of aluminum electrode 4 - polycrystalline silicon 8 - aluminum wiring 3, and no disconnection accidents occur.

Furthermore, as is clear from the drawing, the low-resistivity polycrystalline silicon layer 8 provided under the pad extends to the wiring side through the portions of the metal layers 4 and 3 covered with the second insulating film 5'. It is currently forming. According to this configuration,
The metal layer at the edge of the opening for pad formation provided in the second insulating film 5' maintains the desired thickness even inside, and the metal layer is slightly corroded by the moisture that has entered. Even if the polycrystalline silicon layer is removed, a sufficient thickness remains on the polycrystalline silicon layer, and a sufficient contact area between the polycrystalline silicon and the wiring can be obtained. Therefore, it is possible to maintain the connection between the pad and the wiring with a sufficiently low electrical resistance.

In addition, the polycrystalline silicon of this structure can be used to form multilayer wiring, polycrystalline silicon resistance, etc. at the same time, so it has the advantage of being easy to form without the need for any additional steps. There is. Furthermore, there is no problem with doping polycrystalline silicon with any kind of impurity, and there is no problem even if doped polycrystalline silicon is grown or polycrystalline silicon is doped with impurities by ion implantation, diffusion, etc. . That is, it can be easily made into a conductive layer.

Note that it is sufficient to provide the polycrystalline silicon just below the portion located between the bonding pad and the wiring layer.

[Brief explanation of drawings]

Fig. 1a is a cross-sectional structural diagram of a conventional bonding pad, b is a cross-sectional view showing a conventional structure in which aluminum dissolves in moisture and the wire is broken, and Fig. 2a is a bonding pad according to an embodiment of the present invention. Fig. 2B is a cross-sectional view showing the structure of the present invention when aluminum dissolves in moisture and only the aluminum is disconnected. DESCRIPTION OF SYMBOLS 1... Semiconductor substrate, 2... Oxide film, 3... Aluminum wiring layer, 4... Aluminum electrode (bonding pad), 5, 5'... Insulating film, 6... Bonding line, 7, 7'... ...Opening due to corrosion, 8
...Polycrystalline silicon.

Claims (1)

[Claims] 1 a first insulating film provided on a semiconductor substrate;
a metal layer provided on the first insulating film and having an electrode portion and a wiring portion continuous to a part of the electrode portion; and a second metal layer covering the first insulating film and the metal layer. an insulating film, a part of the electrode part of the metal layer is exposed through an opening provided in the second insulating film, and the exposed part is used as a bonding pad. A polycrystalline silicon layer doped with impurities and having a low resistivity is provided between the bonding pad portion and the first insulating film in contact with the bonding pad portion, and the polycrystalline silicon layer is . A semiconductor device, characterized in that the metal layer is formed to extend toward the wiring section through a portion covered with the second insulating film, and is electrically connected to the wiring section.