JPH05211242A - Semiconductor device and its manufacture - Google Patents

Abstract

PURPOSE:To improve adhesiveness between a metal wiring and an interlayer insulating film provided on a semiconductor substrate. CONSTITUTION:A surface including a metal wiring constituted of a first metal film 4, a second metal film 5, and a gold film 6 is spread with an aluminum film 7 by using sputtering, and an aluminum nitride film 8 by using plasma nitriding; and a silicon oxide film 9 is deposited on them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and its manufacturing method.

[0002]

2. Description of the Related Art A conventional semiconductor device manufacturing method is as follows.
As shown in FIG. 4A, an N-type (or P-type) diffusion layer 2 and a silicon oxide film or a silicon oxide film are formed on one main surface of a P-type (or N-type) silicon substrate 1 with phosphorus or boron. An interlayer insulating film 3 having a thickness of 0.5 to 1.0 μm and formed of a PSG film or a BSPG film to which is added is formed.

Next, after forming a via hole (not shown) at a desired position, a titanium tungsten alloy film or a titanium film and a titanium nitride film in which 5 to 10% of titanium is added to tungsten on the surface including the via hole. A first metal film 4 having a thickness of 0.05 to 0.2 μm and a thickness of 0.01 made of gold, platinum, palladium or the like.
A second metal film 5 having a thickness of .about.0.1 .mu.m is sequentially deposited and formed.

Next, as shown in FIG. 4B, a positive type photoresist film 10 having a thickness of 1.0 to 2.0 μm is selected on the second metal film 5 by using a photolithography technique. And then electrolytically gold-plating the second metal film 5 using the photoresist film 10 as a mask.
To a thickness of 0.5 to 2.0 μm.

Next, as shown in FIG. 4 (c), the photoresist film 10 is removed using an organic solvent, followed by a milling method using argon gas as a source or a reaction using CF ₄ or SF ₆ as an etching gas. The unnecessary portions of the lower first metal film 4 and the second metal film 5 are removed by a positive ion etching method using the gold film 6 as an etching mask, and the first metal film 4 and the second metal film 5 are removed. , A metal wiring composed of a laminated structure of the gold film 6 is formed.

Next, as shown in FIG.
The silicon oxide film 9 or the silicon nitride film is formed on the gold film 6 by the plasma CVD method using H ₄ , N ₂ O, NH ₄ , N ₂ etc. as the source gas.

[0007]

In the conventional semiconductor device described above, it is customary to use a silicon oxide film or a silicon oxide film as an interlayer insulating film provided on the gold film forming the wiring. Is an element that is chemically stable and has poor adhesion to a silicon oxide film or a silicon nitride film, so that it is difficult to obtain mechanical strength of the interlayer insulating film. Therefore, it becomes difficult to obtain a semiconductor device having high long-term reliability and stable characteristics, and a high yield in the manufacturing process cannot be realized.

[0008]

The semiconductor device of the present invention comprises:
A metal wiring formed on an insulating film provided on a semiconductor substrate, a first interlayer insulating film made of a metal oxide film or a metal nitride film provided on the surface including the metal wiring, and the first interlayer A second interlayer insulating film made of a silicon oxide film or a silicon nitride film provided on the insulating film.

A method of manufacturing a semiconductor device according to the present invention comprises a step of selectively providing a metal wiring on an insulating film provided on a semiconductor substrate, and an aluminum film or a titanium film formed on a surface including the metal wiring. A step of forming a first interlayer insulating film of an aluminum oxide film, a titanium oxide film or a titanium nitride film by performing an oxidation treatment or a nitriding treatment; and a silicon oxide film or a nitride film on the first interlayer insulating film. And a step of forming a second interlayer insulating film made of a silicon film.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

1 (a) to 1 (c) and 2 (a) to
(C) is sectional drawing of the semiconductor chip shown in order of process for demonstrating the 1st Example of this invention.

First, as shown in FIG. 1A, an N type (or P type) is formed on one main surface of a P type (or N type) silicon substrate 1.
And a PSG film or a BPSG film in which phosphorus or boron is added to silicon oxide is formed on the silicon substrate 1 including the diffusion layer 2. An interlayer insulating film 3 having a thickness of 1.0 μm is formed. Next, after forming a via hole (not shown) at a desired position, heat resistance is obtained by suppressing atomic diffusion between the diffusion layer 2 and the metal wiring formed in the upper layer on the surface of the interlayer insulating film 3 including the via hole. Titanium is added to tungsten in an amount of 5 to 10% for the purpose of improving the property and supplying the plating current during plating.
The first metal film 4 composed of the added titanium-tungsten alloy film or two layers of a titanium film and a titanium nitride film was used as a D.I. C. Deposition power by magnetron sputtering method 1.
It is formed to a thickness of 0.05 to 0.2 μm under the conditions of 0 to 5.0 kW and a film forming pressure of 2 to 10 mTorr. Next, for the purpose of protecting the surface of the first metal film 4 from the plating solution when forming metal wiring on the first metal film 4 by a plating method, improving adhesion, and supplying a plating current. A second metal film 5 made of gold, platinum, palladium, etc.,
D. C. Deposition power by magnetron sputtering method 0.
It is formed to a thickness of 0.01 to 0.1 μm under the conditions of 5 to 1.0 kW and a film forming pressure of 2 to 10 mTorr.

Next, as shown in FIG. 1B, a photoresist film 10 having a thickness of 0.5 to 2.0 μm is formed on the second metal film 5.
A coating mask having a thickness of m is formed and patterned to form a wiring forming mask. Next, using the photoresist film 10 as a mask,
The second metal film 5 is used as a cathode, and the metal electrode plate obtained by coating the surface of a mesh-shaped titanium plate with platinum is used as an anode.
A gold film 6 is formed on the second metal film 5 by applying a voltage between the positive and negative electrodes in an electrolytic gold plating solution composed of, for example, a gold sulfite solution which is kept at a constant temperature of about 60 ° C. To a thickness of 0.5 to 1.0 μm.

Next, as shown in FIG. 1C, the photoresist film 10 is removed by a stripping method using an organic solvent or an ashing method using oxygen plasma, and then the gold film 6 is removed.
Is used as a mask to etch back by dry etching using SF ₆ , CF ₄ , CC1 ₄ , BC1 _3, etc. as an etching gas to remove the first metal film 4 and the second metal film 5, thereby removing the first metal film. 4, a metal wiring composed of the second metal film 5 and the gold film 6 is formed.

Next, as shown in FIG. 2A, an aluminum film 7 is formed on the surface including the metal wiring by D.P. C. Using a magnetron sputtering method, the film forming power is 0.5 to 1.0 kW, and the film forming pressure is 2 to 10 mTorr.
It is formed to a thickness of m.

Next, as shown in FIG. 2 (b), NH ₄ ,
RF power by plasma nitriding method using N ₂ or the like as a source gas 0.5 to 1.0 kW, film forming pressure 0.1 to 10 Torr
Under these conditions, the aluminum film 7 is plasma-nitrided to form the aluminum nitride film 8.

Next, as shown in FIG.
The aluminum nitride film 8 is formed under the conditions of RF power of 0.5 to 1.0 kW and film forming pressure of 0.1 to 10 Torr using a plasma CVD method using H ₄ , N ₂ O, NH ₄ , N ₂ etc. as a source gas. A silicon oxide film 9 is formed thereon to a thickness of 0.1 to 0.5 μm.

In the wiring structure thus obtained, the aluminum nitride film 8 is present between the gold film 6 which is the wiring metal film and the silicon oxide film 9 which is the interlayer insulating film, and the adhesion between the two is high. Is improving.

Further, in such a method of forming an interlayer insulating film, since the aluminum film 7 is formed by the sputtering method and then subjected to the nitriding treatment, the gold atoms of the gold film 6 are formed by the sputtering method. And the aluminum nitride film 8 can be further improved in adhesion as compared with the case where the aluminum nitride film 8 is directly formed by the sputtering method.

FIGS. 3A to 3D are sectional views of the semiconductor chip in the order of steps for explaining the second embodiment of the present invention.

As shown in FIG. 3A, the interlayer insulating film 3 is formed on the P type diffusion layer selectively provided on one main surface of the P type silicon substrate 1 by the same process as in the first embodiment. And the first metal film 4 and the second metal film 5 are sequentially deposited on the interlayer insulating film 3. Next, using the photoresist film provided on the second metal film 5 as a mask, a copper film 11 having a thickness of 0.5 to 1.0 μm is selectively formed on the second metal film 5 by electrolytic plating. After forming and removing the photoresist film by a peeling method using an organic solvent or an ashing method using oxygen plasma, an ion millinda method using Ar as a milling source or a dry method using CF ₄ , SF ₆ or the like as an etching gas is used. Unnecessary portions of the first metal film 4 and the second metal film 5 are removed by the etching method using the copper film 11 as a mask,
A metal wiring having a laminated structure of the metal film 4, the second metal film 5 and the gold film 6 is formed.

Next, as shown in FIG. 3B, a titanium film 12 is formed on the surface including the gold film 6 by D.P. C. Film formation power of 0.5 to 1.0 kW and film formation pressure of 2 using the magnetron sputtering method
It is formed to a thickness of 0.01 to 0.05 μm under the condition of 10 mTorr.

Next, as shown in FIG. 3C, RF power of 0.5 is used by the plasma oxidation method using O ₂ as a source gas.
The titanium film 12 is subjected to plasma oxidation treatment under the conditions of .about.1.0 kW and film forming pressure of 0.1 to 10 Torr to form the titanium oxide film 13.

Next, as shown in FIG. 3D, an RF power of 0.1 V is applied on the titanium oxide film 12 by a plasma CVD method using SiH ₄ , N ₂ O, NH ₄ , N ₂ etc. as a source gas. 5
The silicon oxide film 9 is formed to a thickness of 0.1 to 0.5 μm under the conditions of ˜1.0 kW and film forming pressure of 0.1 to 10 Torr.

In the wiring structure thus obtained, the titanium oxide film 13 exists between the copper film 11 which is a wiring metal film and the silicon oxide film 9 which is an interlayer insulating film, and the adhesion between the two is high. Is improving.

Further, in such a method for forming an interlayer insulating film, since the titanium film 12 is formed by the sputtering method and then subjected to the oxidation treatment, the copper atoms of the plated copper are different from the titanium atoms formed by the sputtering method. Since they are in close contact, the adhesion can be further improved as compared with the case where the titanium oxide film is directly formed by the sputtering method.

[0027]

As described above, according to the present invention, since the adhesion between the wiring metal film and the interlayer insulating film can be improved, the multilayer insulating film having stable and good electric characteristics and high long-term reliability can be obtained. It has an effect that a wiring structure can be formed.

[Brief description of drawings]

1A to 1C are cross-sectional views of a semiconductor chip showing the order of steps for explaining a first embodiment of the present invention.

FIG. 2 is a sectional view of a semiconductor chip showing the order of steps for explaining the first embodiment of the present invention.

FIG. 3 is a cross-sectional view of a semiconductor chip showing the order of steps for explaining a second embodiment of the present invention.

FIG. 4 is a cross-sectional view of a semiconductor chip showing the order of steps for explaining a conventional method for manufacturing a semiconductor device.

[Explanation of symbols]

 1 Silicon Substrate 2 Diffusion Layer 3 Interlayer Insulation Film 4 First Metal Film 5 Second Metal Film 6 Gold Film 7 Aluminum Film 8 Aluminum Nitride Film 9 Silicon Oxide Film 10 Photoresist Film 11 Copper Film 12 Titanium Film 13 Titanium Oxide Film

Claims (4)

[Claims] 1. A metal wiring formed on an insulating film provided on a semiconductor substrate, and a first interlayer insulating film made of a metal oxide film or a metal nitride film provided on a surface including the metal wiring, A second interlayer insulating film made of a silicon oxide film or a silicon nitride film provided on the first interlayer insulating film, and a semiconductor device. 2. The semiconductor device according to claim 1, wherein the metal wiring comprises a plurality of conductive layers containing at least a gold film or a copper film. 3. The first interlayer insulating film is aluminum oxide,
The semiconductor device according to claim 1 or 2, which is either a titanium oxide film or an aluminum nitride film. 4. A step of selectively providing a metal wiring on an insulating film provided on a semiconductor substrate, and an oxidation treatment or a nitriding treatment to form an aluminum film or a titanium film on a surface including the metal wiring and to perform oxidation. A step of forming a first interlayer insulating film made of an aluminum film, a titanium oxide film or a titanium nitride film, and a second interlayer made of a silicon oxide film or a silicon nitride film on the first interlayer insulating film. And a step of forming an insulating film.