JPS60109224A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To form the electrode which has a good ohmic contact for a semiconductor substrate and is extremely stable thermally by performing ion implantation of the same semiconductor as the semiconductor substrate into a main electrode wiring metal and if necessary, into the aperture part of the semiconductor substrate and subjecting the substrate to heat treatment to form the alloy of the main electrode wiring metal and the ion-implanted semiconductor. CONSTITUTION:A predetermined P-N junction is formed and apertures 3 for forming a contact are arranged on the surface of a semiconductor substrate 1 which is the Si substrate convered with an electric insulating coating 2, e.g., an Si oxide film by using photo-etching technic. Next, on the surface of the semiconductor substrate 1 which is the Si substrate provided with the apertures 3, the metallic film 5 consisting of an Al film is formed by spattering or vapor deposition. Next, Si atoms which are the same semiconductor material as of the semiconductor substrate 1 are ion-implanted to form a semiconductor ion implantation layer 6 which is an Si ion implantation layeor. Then the metallic film 5 consisting of Al film ion-implanted is patterned by photo-etching technic to form an electrode wiring, followed by sintering to complete the electrode wiring 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method of manufacturing a semiconductor device, and particularly to a method of forming electrode wiring of a semiconductor device having a shallow junction.

[Prior art]

Conventionally, aluminum has generally been used as an electrode material for semiconductor devices, but since aluminum undergoes an alloy reaction with semiconductor materials at relatively low temperatures, it is often used in transistors for ultra-high frequency amplifiers, ultra-high speed switches, etc. In the case of a semiconductor device having a shallow junction or in which the diffusion window and the electrode extraction window are the same, there is a drawback that the alloy reaction region easily reaches the junction and destroys the junction.

For this reason, conventional semiconductor devices using aluminum electrodes have been extremely unstable thermally.

Hereinafter, for convenience of explanation, the materials most commonly used at present, ie, silicon as the semiconductor and aluminum as the entire area of the main electrode wiring, will be described as an example.

The main cause of bond failure due to an alloy reaction between a silicon substrate and an aluminum electrode is that when silicon and aluminum are heated to a high enough temperature (generally 350 to 600°C) that a slight alloy reaction occurs, i.e., sintered, the electrode openings are damaged. At the same time as the silicon diffuses into the aluminum, the aluminum also enters the silicon substrate, causing the base joint to become an aluminum oxide...
It is known that this is due to a short circuit caused by the mu-silicon alloy.

Conventional methods for preventing this junction short circuit include (a) a two-layer structure consisting of a high melting point metal such as nickel, tantalum, or titanium and aluminum, or platinum.

A compound of silicon and molybdenum is formed between the silicon substrate and aluminum to prevent the substrate silicon from diffusing into the aluminum.

(b) Vapor depositing or sputtering an aluminum-silicon alloy to form a silicon-containing sia aluminum wiring to prevent substrate silicon from diffusing into the aluminum wiring.

(c) A multilayer wiring structure using gold, silver, etc. as the main material without using aluminum.

These methods are known, but they have many drawbacks, such as the manufacturing method being too complicated, the realization difficult, the contact resistance being too high, and the variation being large.

[Object of the Invention] An object of the present invention is to provide a method for manufacturing a thermally stable semiconductor device, which eliminates the above-mentioned drawbacks, obtains a good ohmic connection between a semiconductor substrate and an electrode metal, and is thermally stable.

[Structure of the invention]

A method for manufacturing a semiconductor device according to a first aspect of the present invention includes the steps of providing an opening in an electrically insulating film that covers the entire surface of a semiconductor substrate, a step of depositing a metal film on the substrate, and a step of depositing a metal film on the substrate. a step of ion-implanting the same semiconductor material as that of the semiconductor substrate, a step of at least partially alloying the metal film and the ion-implanted semiconductor material, and a step of patterning the metal film to form electrode wiring. It consists of:

Further, the second invention Q semiconductor device manufacturing method of the present invention includes:
A step of forming an opening in an electrically insulating film that covers the whole surface of a semiconductor substrate, and forming a hole in the semiconductor substrate through the opening, the same as that of the substrate.
A step of ion-implanting a semiconductor material, a step of depositing a metal film on the substrate, a step of ion-implanting the same semiconductor material as the semiconductor substrate into the metal film, and a step of ion-implanting the metal film and the ion-implanted semiconductor material. The method includes a step of at least partially alloying the metal film, and a step of patterning the metal film to form electrode wiring.

[Explanation of Examples]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1(a) to 1(c) are sectional views shown in order of steps for explaining an embodiment of the first invention of the present invention.

A predetermined PN junction is formed as shown in FIG. 1(a)K,
Openings 3 for forming contacts are formed in the electrically insulating film 2 of the semiconductor substrate 1, which is a silicon substrate whose surface is covered with an electrically insulating film 21, for example, a silicon oxide film, using a photoetching technique.
will be established.

Next, as shown in FIG. 1(b), the surface of the semiconductor substrate 1, which is a silicon substrate provided with the opening 3, is coated with a thickness of 0.6 μm.
A metal film 5 such as an aluminum film having a thickness of approximately 1.5 m is formed by sputtering or vapor deposition.

Next, silicon atoms, which are the same semiconductor material as the semiconductor substrate 1, are ion-implanted to form a semiconductor ion-implanted layer 6, which is a silicon ion-implanted layer. In this case, the ion implantation conditions for silicon atoms are acceleration voltage 200KV, implantation * 3.6X
Assuming 10"/an", it is appropriate that the range is 0.24 μm and the density of silicon in aluminum is 1% of that of aluminum.

Next, as shown in FIG. 1(C), the ion-implanted metal film 5, such as an aluminum film, is patterned using a photoetching technique to form an electrode wiring.Then, it is sintered at 450°C for about 10 minutes. Particularly, the stain electrode wiring 7 is completed. In this embodiment, by this sintering, the ion-implanted silicon is diffused into the aluminum film, and most of it is converted into an aluminum-silicon alloy.

According to this embodiment, the t-electrode wiring is formed of an aluminum-silicon alloy because silicon ions are implanted into the aluminum film, and the aluminum-silicon alloy is saturated with silicon, and then heat-treated (generally at a temperature lower than the sintering temperature). ), the substrate silicon does not diffuse into the aluminum-silicon alloy wiring, and the bonding becomes extremely stable thermally.Also, by the time the silicon diffuses into the entire aluminum film, a slight amount of alloying occurs at the interface between the silicon substrate and the aluminum film. Because of this, good ohmic contact with the silicon substrate can be achieved.

Furthermore, an electrical insulating film may be deposited on the aluminum film if necessary.

In this example, sintering was performed after patterning the electrode wiring, but the present invention is not limited to this.
Sintering may be performed before patterning the electrode wiring.

FIG. 2 is a sectional view of a part of the process for explaining an embodiment of the second aspect of the present invention.

In this example, the same steps as those shown in FIGS. 1(a) to fc) will be described with reference to them.

First, a PN junction with a constant % Par is formed in the same manner as shown in FIG. Opening 3t for contact formation using photoetching technology
- Provide.

Next, as shown in FIG. 2, silicon, which is the same semiconductor material as the semiconductor substrate 1, is ion-implanted to a shallow depth that does not reach the junction, and an excess semiconductor ion implantation layer IwI4, which is an excess silicon ion-implanted layer, is implanted near the surface of the silicon substrate. Form.

Next, a metal film 5 such as an aluminum film is deposited on the substrate.

Next, silicon, which is the same semiconductor material as the semiconductor substrate, is ion-implanted into the all-pole film 5, which is an aluminum film, to form a semiconductor ion-implanted layer 6, which is a silicon ion-implanted layer.

Next, as in the case of FIG. 1(c), the metal film 5 made of the ion-implanted aluminum film is patterned by photoetching to form electrode wiring.

Next, sinter at 450℃ for about 10 minutes.
Electrode wiring is completed. Note that defects in the silicon substrate that have been removed by ion implantation are not a problem because they can be recovered by the sinter trap.

According to this example, ion implantation is performed before depositing the aluminum film, so that excess silicon exists in the openings of the silicon substrate, and since sufficient ion implantation is also performed in the aluminum film, the sintering In this case, the diffusion of silicon from the substrate into the aluminum film can be completed with only this ion-implanted excess silicon, which provides good ohmic contact and at the same time prevents the diffusion of silicon from the substrate into the aluminum film. This is especially advantageous when manufacturing semiconductors with shallow junctions.

〔Effect of the invention〕

As explained above, according to the present invention, the same semiconductor as the semiconductor substrate is ion-implanted into the main electrode wiring metal and, if necessary, into the opening of the semiconductor substrate and heat-treated. By forming an alloy with the ion-implanted semiconductor and the ion-implanted semiconductor, a semiconductor device is obtained that has a very thermally stable electrode with good fourth microcontact to the semiconductor substrate.

[Brief explanation of drawings]

11) to (C) are sectional views shown in the order of steps for explaining an embodiment of the first invention of the present invention, and FIG. 2 is a sectional view showing an embodiment of the second invention of the present invention. It is a sectional view of a part of the process of the pot. 1... Semiconductor substrate, 2... Electrical insulating film, 3... Opening, 4... Excessive semiconductor ion implantation layer, End... Metal film, 6... Semiconductor ion implantation layer, 7... Electrode wiring.

Claims (2)

[Claims] (1) A step of providing an opening in an electrically insulating film covering the whole surface of a semiconductor substrate, and a step of depositing a metal film on the substrate,
A step of ion-implanting the same semiconductor material as that of the semiconductor substrate into the metal film, a step of alloying the metal film and the ion-implanted semiconductor material at least in four parts, and patterning the metal film to form electrode wiring. 1. A method of manufacturing a semiconductor device, the method comprising: forming a semiconductor device. (2) A step of providing an opening in an electrically insulating film covering the whole surface of a semiconductor substrate, a step of ion-implanting the same semiconductor material as that of the substrate into the semiconductor substrate through the opening, and a step of forming a gold steel film on the substrate. a step of ion-implanting the same semiconductor material as the semiconductor substrate into the metal film; a step of at least partially alloying the metal film and the ion-implanted semiconductor material; 1. A method for manufacturing a semiconductor device, comprising the steps of: patterning a semiconductor device to form an electrode wiring;