JPH0799244A - Semiconductor device - Google Patents

Abstract

PURPOSE:To provide a semiconductor device having the sufficient electrostatic withstand voltage by increasing the withstand voltage at the intersecting part of wirings where two kinds of voltages are applied. CONSTITUTION:A polysilicon film 13 for cutting and reconnecting an Al film wiring 11 for applying the first voltage and an Al film wiring 12 for applying the second voltage are intersected through an insulating film 15. A polysilicon film 1 is provided at the intermediate part of the wirings through the insulating film 15. Thus, the concentration of the voltage at a pattern edge part is dispersed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a multilayer conductive film.

[0002]

2. Description of the Related Art As a conductive film, a two-layer polysilicon film and one
In a semiconductor device having a two-layer AL film (aluminum film), the polysilicon film is mainly formed as a gate electrode,
The AL film is connected as a wiring to apply a predetermined voltage to the polysilicon gate electrode and the silicon substrate.

In the semiconductor device as described above, all kinds of voltages to be applied to the polysilicon gate electrode and the silicon substrate are supplied by the AL film having a low resistance. In the conventional technique, the following is performed when it is necessary to intersect two types of wirings that do not have the same voltage. That is, after the AL film wiring to which the first voltage is applied is cut at the intersection, reconnection is performed using a polysilicon film, and the second voltage A is applied.
The purpose has been achieved by arranging the L film wiring on the above-mentioned polysilicon film to which the first voltage is applied via the insulating film.

A description will be given below with reference to the drawings. FIG. 3 is a wiring schematic diagram of a conventional semiconductor device. In FIG. 3, 8 is a wiring to which a first voltage is applied, and 9 is a wiring to which a second voltage is applied. 4A is a plan view showing an intersection of the wirings in FIG. 3, and FIG. 4B is a sectional view taken along line ZZ ′ in FIG. In FIG. 4, 10 is a silicon substrate and 11 is a first
AL film wiring to which the voltage is applied, 12 is an AL film wiring to which the second voltage is applied, 13 is a polysilicon film for reconnecting the wiring to which the first voltage is applied, 14 is a contact hole, 1
Reference numeral 5 is an insulating film.

As shown in FIG. 4, at the intersection of the wirings of the conventional semiconductor device, the AL film wiring 12 is the AL film wiring 1
The upper part of the polysilicon film 13 that reconnects 1 is wired via the insulating film 15. In the conventional technique, two kinds of wirings are crossed as described above to supply various kinds of voltages.

[0006]

However, in the above-mentioned conventional structure, the electrostatic breakdown voltage between the polysilicon film 13 and the AL film wiring 12 is insufficient. A high voltage may be momentarily applied to the semiconductor device due to the influence of static electricity or the like. As a countermeasure, it is often the case that a protection circuit is provided to release a high voltage. However, there are cases where a sufficient protection circuit cannot be provided due to the layout.

A diffusion layer may be provided under the bonding pad when the area of the protection circuit is insufficient in layout. However, this method causes a thin oxide film under the bonding pad, which causes a problem in strength during wire bonding. It is dangerous because it occurs. When a sufficient protection circuit is provided, there is no problem of electrostatic withstand voltage, but when it is not, the conventional technique has an insufficient electrostatic withstand voltage where the wiring intersects.

FIG. 5 is a partially enlarged view of FIG. 4 (b). A local high voltage is apt to be applied to the portion A surrounded by a circle in FIG. 5, which causes dielectric breakdown and short-circuits the AL film wiring 12 and the polysilicon film 13. In view of the above point, the present invention has an object to provide a semiconductor device having a sufficient electrostatic breakdown voltage at the intersection of wirings.

[0009]

According to another aspect of the present invention, there is provided a semiconductor device in which an insulating film between a first conductive film to which a first voltage is applied and a second conductive film to which a second voltage is applied is provided in a third insulating film. A feature is that a conductive film is provided.

[0010]

According to the structure of the present invention, the local high voltage which is about to be generated between the first conductive film to which the first voltage is applied and the second conductive film to which the second voltage is applied is intermediate. It is possible to increase the electrostatic breakdown voltage by spatially dispersing it by the third conductive film located at.

[0011]

1A is a plan view of a wiring intersection portion of a semiconductor device according to a first embodiment of the present invention, and FIG. 1B is a sectional view taken along line XX '. In FIG. 1, 1 is a polysilicon film (third
Conductive film), 10 is a silicon substrate, 11 is an AL film wiring to which a first voltage is applied, 12 is an AL film wiring to which a second voltage is applied (second conductive film), and 13 is an AL film to which a first voltage is applied. A polysilicon film (first conductive film) for reconnecting the film wiring 11, 14 is a contact hole for connecting the AL film wiring 11 to which the first voltage is applied and the polysilicon film 13, and 15 is an insulating film.

This semiconductor device has a polysilicon film 13 to which a first voltage is applied and an AL film wiring 12 to which a second voltage is applied.
And the polysilicon film 1 is provided with the insulating film 15 interposed therebetween. The polysilicon film 1 is provided so as to cover the polysilicon film 13 to which the first voltage is applied. In this semiconductor device configured as described above, the polysilicon film 1
However, between the polysilicon film 13 to which the first voltage is applied and the AL film wiring 12 to which the second voltage is applied, the function of preventing the concentration of the voltage on a portion where a voltage is easily applied locally, such as an edge portion, is prevented. Therefore, the electrostatic breakdown voltage can be increased.

FIG. 2A is a plan view of a wiring intersection portion of a semiconductor device according to a second embodiment of the present invention, and FIG. 2B is its YY 'section.
FIG. In FIG. 2, 2 is a polysilicon film (third conductive film), and other parts corresponding to those in FIG. 1 are denoted by the same reference numerals. In this semiconductor device, instead of the polysilicon film 1 of FIG. 1, the polysilicon film 2 is replaced by a polysilicon film 13 to which a first voltage is applied and an A to which a second voltage is applied.
It is provided between the L film wiring 12 and the polysilicon film 13 so as to cover the edge portion of the polysilicon film 13.

Also in the semiconductor device of this embodiment configured as described above, since the polysilicon film 2 covers the edge portion of the polysilicon film 13, it functions to disperse the voltage concentrated on the edge portion. Therefore, the electrostatic breakdown voltage can be increased. Although the polysilicon films 1 and 2 in the first and second embodiments are floating in terms of voltage, it goes without saying that they may be grounded.

Further, the polysilicon film 2 in the second embodiment is divided into two pieces, but it goes without saying that they may be connected in part. Further, although the AL conductive film and the polysilicon film are used as the conductive film in both the first and second embodiments, it goes without saying that this may be another conductive film. In the above example, when the electrostatic breakdown voltage test, which is generally performed in the industry, was evaluated at 100 pF-0Ω, the electrostatic breakdown voltage at the wiring intersection was 50 V, but was improved to 200 V or more. This is particularly effective for a semiconductor device in which a sufficient protection circuit is not provided.

[0016]

According to the semiconductor device of the present invention, a local high voltage to be generated between the first conductive film to which the first voltage is applied and the second conductive film to which the second voltage is applied, It is possible to increase the electrostatic withstand voltage by spatially dispersing the third conductive film located in the middle.

[Brief description of drawings]

FIG. 1A is a plan view of a wiring intersection portion of a semiconductor device according to a first embodiment of the present invention, and FIG. 1B is a sectional view taken along line XX ′ of FIG.

FIG. 2A is a plan view of a wiring intersection portion of a semiconductor device according to a second embodiment of the present invention, and FIG. 2B is a sectional view taken along the line YY ′.

FIG. 3 is a wiring schematic diagram of a conventional semiconductor device.

FIG. 4A is a plan view of a wiring intersection portion of a conventional semiconductor device, and FIG. 4B is a ZZ ′ sectional view thereof.

5 is a partially enlarged view of FIG. 4 (b).

[Explanation of symbols]

 1, 2 Polysilicon Film (Third Conductive Film) 12 AL Film Wiring (Second Conductive Film) 13 Polysilicon Film (First Conductive Film) 15 Insulating Film

Claims (1)

[Claims] 1. A first conductive film, to which a first voltage is applied, and a second voltage, which is located above the first conductive film so as to intersect with the first conductive film via an insulating film. A semiconductor device comprising a second conductive film, wherein a third conductive film is provided in the insulating film between the first conductive film and the second conductive film. apparatus.