JPS62155539A - Semiconductor device - Google Patents

Abstract

PURPOSE:To improve yield on manufacture and reliability by constituting a wiring electrode of a leading-out electrode, a side surface thereof is coated with an oxide film, and a wiring metal formed, coating the surface of the leading-out electrode. CONSTITUTION:A diffusion layer 12 consisting of an N-type impurity is shaped to the surface of a P-type silicon substrate 11, and an insulating film 13 composed of an silicon oxide film, etc. is formed onto the N-type diffusion layer 12. A leading-out electrode 14 connected to the N-type diffusion layer 12 through an opening section bored to the insulating film 13 and consisting of polycrystalline silicon is shaped onto the insulating film 13, and constitutes a wiring electrode 20 together with an aluminum film 15 as a wiring metal formed, coating the leading-out electrode 14. Silicon oxide 17 is shaped on the side surface of the leading-out electrode 14. 14A represents a polycrystalline silicon wiring, and organizes a metallic wiring 30 integrally formed with the wiring electrode 20 together with the aluminum film 15.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a semiconductor device.

[Conventional technology]

Conventionally, as a method for forming wiring electrodes in a semiconductor device, a lead electrode made of polycrystalline silicon is provided at an electrode lead-out portion from a diffusion layer on the surface of a semiconductor substrate, and then a wiring metal made of aluminum or the like is placed above it. It is being done. This is to protect the shallow diffusion layer from the wiring metal.

FIG. 3 is a sectional view of a semiconductor device having a conventional wiring electrode structure.

In FIG. 3, 11 is a P-type silicon substrate, 12 is an N-type diffusion layer formed on the surface of the P-type silicon substrate 11, and 13A is a silicon oxide film formed on the surface of the P-type silicon substrate 11 including the N-type diffusion layer 12. An opening is provided for drawing out the electrode.

A method for forming wiring electrodes will be described below.

First, in the N-type diffusion layer 12, P containing the silicon oxide film 13A is formed.
After growing polycrystalline silicon on the surface of the mold silicon substrate 11 by vapor phase growth, the lead electrode 14 and the polycrystalline silicon wiring 14A are formed by photolithography. Subsequently, impurities are introduced into the polycrystalline silicon using ion implantation technology to make it conductive, and then, as a wiring metal, for example, an aluminum film 15 is deposited over the entire surface by vapor deposition or sputtering. Subsequently, by removing the aluminum film other than the extraction electrode 14 and the polycrystalline silicon wiring 14A using photolithography technology, the wiring electrode 20 consisting of the extraction electrode 14 and the aluminum film 15, the polycrystalline silicon wiring 14A, and the aluminum film 15 are removed. The metal wiring 30 is completed.

[The problem that the invention attempts to solve]

The semiconductor device having the wiring electrode of the conventional structure described above has the following problems.

(1) Due to the reaction between the wiring electrode and polycrystalline silicon at the side surface of the wiring electrode, the resistance inside the lead-out electrode becomes uneven, resulting in a shortened lifespan of the wiring electrode.

(2) Wiring metal invades the diffusion layer through the defective region at the interface between the oxide film and the extraction electrode, destroying the PN junction of the diffusion layer.

(3) If the polycrystalline silicon layer is exposed on the side surface of the wiring electrode during the etching process, contaminants will enter the diffusion layer from the interface between the oxide film and the polycrystalline silicon, thereby shortening the life of the device.

For this reason, the manufacturing yield and reliability of semiconductor devices have decreased.

An object of the present invention is to eliminate the above-mentioned problems and provide a semiconductor device with improved manufacturing yield and reliability.

[Means for solving problems]

The semiconductor device of the present invention includes a diffusion layer of an opposite conductivity type impurity formed on a conductivity type semiconductor substrate, an insulating film formed on the diffusion layer, and a diffusion layer formed on the insulating film and provided on the insulating film. A semiconductor device comprising an extraction electrode made of polycrystalline silicon that is connected to the diffusion layer through a hole formed in the opening, and a wiring electrode made of wiring metal formed covering a surface of the extraction electrode, the wiring electrode being in contact with the wiring metal. The side surface of the extraction electrode is covered with an oxide film.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of an embodiment of the present invention.

In FIG. 1, a diffusion layer 12 made of N-type impurities is formed on the surface of a P-type silicon substrate 11, and an insulating film 13 made of a silicon oxide film or the like is formed on this N-type diffusion layer 12. ing.

A lead electrode 14 made of polycrystalline silicon is formed on this insulating film 13 and is connected to the N-type diffusion layer 12 through an opening provided in the insulating film 13. The aluminum film 15 constitutes the wiring chamber %20. and,
Silicon oxide 17 is formed on the side surface of this extraction electrode 14. Note that 14A is a polycrystalline silicon wiring, which together with the aluminum film 15 constitutes a metal wiring 30 that is integrally formed with the wiring electrode 20. There is.

In this embodiment configured in this way, the extraction electrode 1
Since the silicon oxide film 17 is formed on the side surface of the aluminum 15, the influence of the lead electrode I\ of the aluminum 15 from the side surface is eliminated. Therefore, the internal resistance of the extraction electrode 14 becomes uniform,
Breakdown of the PN junction is eliminated.

Further, even if the aluminum 15 on the side surface of the extraction electrode 14 is removed in the etching process, the silicon oxide film 17 prevents contaminants from entering, so the life of the device will not be shortened.

Next, a manufacturing method for this example will be explained.

FIGS. 2(a) to 2(c) are cross-sectional views of a semiconductor chip shown in order of steps for explaining a manufacturing method according to an embodiment of the present invention.

First, as shown in FIG. 2(a), a P-type silicon substrate 11
After forming an N-type diffusion layer 12 and an insulating film 13 made of a silicon oxide film or the like thereon, openings are formed in predetermined portions of the insulating film 13. Subsequently, a polycrystalline silicon film and a silicon nitride film 16 are successively deposited on the entire surface by CVD, and then buttered to form an extraction electrode 14 made of a polycrystalline silicon film.
form. Note that 14A is a polycrystalline silicon wiring that constitutes the metal wiring 30.

Next, as shown in FIG. 2(b), the silicon nitride film 16
Using as a mask, thermal oxidation is performed to form a silicon oxide film 17 on the side surface of the extraction electrode 14.

At this time, a silicon oxide film 17 is simultaneously formed on the side surface of the polycrystalline silicon wiring 14A.

Next, as shown in FIG. 2(c), the silicon nitride film 16
is removed using hot phosphoric acid solution. Next, impurities are introduced into the extraction electrode 14 and the polycrystalline silicon wiring 14A by ion implantation to make them conductive. Next, as shown in FIG. 1, aluminum is deposited on the entire surface by vapor deposition or sputtering. Thereafter, patterning is performed to form a wiring electrode 20 consisting of a lead electrode 14 and an aluminum film 15.

At the same time, a metal wiring 30 consisting of the polycrystalline silicon wiring 14A and the aluminum film 5 is also formed integrally with the wiring electrode 20.

Although the above embodiments have been described using a P-type silicon substrate, it goes without saying that an N-type silicon substrate may also be used.

[Effect of the invention J As explained above, the present invention provides an extraction electrode whose side surface is covered with an oxide film, and a wiring metal layer formed covering this surface)
By configuring the wiring electrodes, the following effects can be obtained.

(1) Since the internal resistance of the lead electrode is made uniform, the life of the wiring electrode is extended.

2) Since the penetration of wiring metal into the diffusion layer is prevented, PN
The bond will not be destroyed.

(3) Process: Even if wiring metal is removed from the side surfaces of wiring electrodes in the I-ding process, the oxide film prevents contaminants from entering, so the life of the element will not be shortened.

As a result of the above, the manufacturing yield and reliability of semiconductor devices can be significantly improved.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, and FIGS. 2(a) to (
C) is a cross-sectional view of a semiconductor chip shown in the order of steps for explaining the manufacturing method of the embodiment of FIG. 1, and FIG. 3 is a cross-sectional view of an example of a conventional semiconductor device. 1... P-type silicon substrate ,
12... N-type diffusion layer, 13... Insulating film, 13A...
・Silicon oxide film, 14... Leading electrode, 14A...
・Polycrystalline silicon wiring, 15...aluminum film, 1
6 silicon nitride film, 17 silicon oxide film, 20... wiring electrode, 30... metal wiring.

Claims (1)

[Claims] A diffusion layer of an opposite conductivity type impurity formed on a semiconductor substrate of one conductivity type, an insulating film formed on the diffusion layer, and an opening formed on the insulating film and provided in the insulating film. In a semiconductor device having an extraction electrode made of polycrystalline silicon connected to a diffusion layer and a wiring electrode made of wiring metal formed covering the surface of the extraction electrode, a side surface of the extraction electrode in contact with the wiring metal is formed with an oxide film. A semiconductor device characterized by being covered with.