JPH08269711A - Production of semiconductor device - Google Patents

Abstract

PURPOSE: To improve the reliability of the wiring of a semiconductor device. CONSTITUTION: Gaseous oxygen is introduced into a chamber in the final stage of the sputtering to form an Al wiring layer 12 on an insulating film 11 on a semiconductor substrate 10 to oxidize th.e Al as the wiring material, and an aluminum oxide film 13 is formed on the Al wiring layer 12. Since the aluminum oxide film 13 is easily and efficiently formed in optional thickness on the Al wiring layer 12, the stress resistance of the Al wiring layer 12 is improved, and the disconnection of the Al wiring layer 12 due to the stress migration, etc., is obviated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for manufacturing a semiconductor device capable of preventing disconnection of wiring and improving reliability.

[0002]

2. Description of the Related Art Conventionally, as a wiring material for a semiconductor device, Al or an Al-based alloy, which has low resistance, good adhesion to a substrate and is inexpensive, has been used. However, wiring composed of Al or Al-based alloy causes stress migration due to the stress of the insulating film (oxide film such as SiO ₂ or nitride film such as SiN _x ) formed on the wiring. There was a problem such as disconnection. Furthermore, these phenomena are likely to occur with the miniaturization and multi-layering of Al wiring. Therefore, in order to withstand the stress of the Al wiring, conventionally, oxygen ions are implanted into the Al wiring or the Al wiring is anodized to oxidize the surface of the Al wiring.

Based on FIG. 5, Al is formed by oxygen ion implantation.
An example of a method of oxidizing the surface of the wiring pattern will be described. FIG. 5 is a sectional view of a semiconductor substrate having an Al wiring pattern formed on the upper surface. In the figure, 1 is a semiconductor substrate, 2 is an insulating film formed on the semiconductor substrate 1, and 3 is an Al wiring pattern formed on the insulating film 2. In this method, after the Al wiring pattern 3 is formed, oxygen ions are injected into the surface (top surface and side surface) of the Al wiring pattern 3 to oxidize the surface of the Al wiring pattern 3.

Next, an example of a method of oxidizing the surface of the Al wiring layer by anodic oxidation will be described with reference to FIG. FIG. 6 is a cross-sectional view showing a step of immersing a semiconductor substrate having an Al wiring layer formed on its upper surface in an oxalic acid solution and anodizing it. However, the same components as those shown in FIG. 5 are designated by the same reference numerals. In the figure, 1 is a semiconductor substrate, 2 is an insulating film formed on the semiconductor substrate 1, and 4 is an insulating film formed on the insulating film 2.
Al wiring layer, 5 is a container, 6 is an oxalic acid solution filled in the container 5, 7 is a DC power supply, 8 is a positive electrode attached to the upper surface of the Al wiring layer 4 and connected to the positive electrode of the DC power supply 7. , 9 are negative electrodes arranged in the oxalic acid solution 6 and connected to the negative electrode of the DC power supply 7. As shown in the figure, the surface of the Al wiring layer 4 was oxidized by applying a direct current to the Al wiring layer 4 by the DC power supply 7 in the oxalic acid solution 6.

[0005]

By the way, in the ion implantation method shown in FIG. 5, it is necessary to perform heat treatment to activate oxygen ions after the implantation of oxygen ions, which increases the number of steps. In addition to the above, there is a problem in that the process shifts to lower temperatures due to the miniaturization of semiconductor devices.

Further, in order to carry out anodization, as shown in FIG. 6, it is necessary to immerse the semiconductor substrate 1 in the oxalic acid solution 6, and the anodizing step, the washing step after the anodizing step, and the washing step after the anodizing step are performed. Since it is necessary to add a drying step and the number of steps is increased, there is a problem that productivity is reduced due to time and labor.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method of manufacturing a semiconductor device which is easy to manufacture and which can improve reliability of wiring.

[0008]

In order to achieve the above object, a method of manufacturing a semiconductor device according to claim 1 is a method of manufacturing a semiconductor device, wherein a wiring layer is formed on a semiconductor substrate. At the final stage of the sputtering process,
Sputtering is performed while oxidizing, nitriding, or nitriding and oxidizing the wiring material to be deposited in an atmosphere of oxygen, nitrogen, or a mixed gas of oxygen and nitrogen.

A method of manufacturing a semiconductor device according to claim 2 is
In a method for manufacturing a semiconductor device in which a wiring pattern is formed on a semiconductor substrate, after forming the wiring pattern, oxygen,
Alternatively, the sputtering is performed while oxidizing, nitriding, or nitriding and oxidizing the wiring material to be deposited in an atmosphere of nitrogen or a mixed gas of oxygen and nitrogen.

[0010]

In the method of manufacturing a semiconductor device according to claim 1, oxygen gas (or nitrogen gas, or a mixed gas of oxygen and nitrogen) is added at the final stage of the sputtering step for forming the wiring layer.
Of the metal oxide film (or the metal nitride film or the metal oxynitride film) having an arbitrary thickness on the upper surface of the wiring layer by introducing the Can be relaxed.

In the method of manufacturing a semiconductor device according to the second aspect, after the wiring pattern is formed, the sputtering is performed while introducing oxygen gas (or nitrogen gas or a mixed gas of oxygen and nitrogen) into the chamber. Since a metal oxide film (or metal nitride film or metal oxynitride film) having an arbitrary thickness can be easily formed on the surface (top surface and side surface) of the wiring pattern, the stress applied to the wiring pattern can be relaxed. You can

That is, according to the method of manufacturing a semiconductor device according to the first or second aspect, there is no need for a step of immersing the semiconductor device in an oxalic acid solution or performing a heat treatment after ion implantation, so that the productivity is lowered. Can improve the stress resistance of the wiring (wiring layer or wiring pattern),
It is possible to easily prevent disconnection of wiring due to stress migration or the like.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the method for manufacturing a semiconductor device of the present invention will be described with reference to FIG. The figure is a cross-sectional view of a semiconductor substrate on which a wiring pattern is formed. In (a),
Reference numeral 10 is a semiconductor substrate, 11 is an insulating film formed on the semiconductor substrate 10, and 12 is a wiring layer (Al wiring layer) formed on the insulating film 11 for forming a wiring pattern.

First, as shown in FIG.
After forming the insulating film 11 on the insulating film 11, the Al wiring layer 12 is formed on the insulating film 11 by sputtering to a desired film thickness. Then, sputtering is continuously performed while introducing oxygen gas into the chamber. Thereby, as shown in (b), the Al oxide film 13 can be easily formed on the Al wiring layer 12 to have an arbitrary thickness. Thereafter, as shown in (c), a wiring pattern (Al wiring pattern 14) having an Al oxide film 13 formed on the upper surface is formed through a photolithography step and an etching step, thereby completing the wiring pattern forming step.

Next, an embodiment of a semiconductor device formed by using the method for manufacturing the semiconductor device shown in FIG. 1 will be described with reference to FIG. In the figure, 15 is a semiconductor substrate, 16 is an insulating film formed on the semiconductor substrate 15, 17 is a wiring layer (first layer Al wiring layer) formed on the insulating film 16, and 18 is a first layer.
An Al oxide film formed on the Al wiring layer 17, 19 is an interlayer insulating film formed on the Al oxide film 18, and 20 is an interlayer insulating film 19.
A wiring layer (second Al wiring layer) formed above, 21 is an Al oxide film formed on the second Al wiring layer 20, and 22 is a passivation film formed on the Al oxide film 21. is there.

In the embodiment shown in FIG. 2, oxygen gas is introduced into the chamber at the final stage of each sputtering step for forming the first Al wiring layer 17 or the second Al wiring layer 20, which is a wiring layer. By introducing and continuing the sputtering, the first-layer Al wiring layer 17 or the second-layer Al wiring layer 20 can be easily formed.
On the upper surface of the metal oxide film, the Al oxide film 18 or the oxide film.
The Al film 21 can be formed.

Further, the isolation layer 23 made of an insulating material, which reaches the interlayer insulating film 19 from the insulating film 16 and divides the first layer Al wiring layer 17, or the first layer Al wiring layer 17 and the second layer Al that is a wiring material for connecting to the second layer Al wiring layer 20
The through-holes 24 in each of which are deposited inside are formed after the sputter step of forming the Al oxide film 18 (the final step of the sputter step of forming the first-layer Al wiring layer 17), or
After the step of forming the interlayer insulating film 19, it is formed by a normal semiconductor process technique including a photolithography step and an etching step.

A different embodiment of the semiconductor device manufacturing method of the present invention will be described with reference to FIG. The figure is a cross-sectional view of a semiconductor substrate on which a wiring pattern is formed. However, the same components as those shown in FIG. 1 are designated by the same reference numerals. In (a), 10 is a semiconductor substrate, 11 is an insulating film formed on the semiconductor substrate 10, and 12 is an insulating film 11.
A wiring layer (Al wiring layer) formed on the wiring layer for forming a wiring pattern.

First, as shown in FIG.
After forming the insulating film 11 on the insulating film 11, the Al wiring layer 12 is formed on the insulating film 11 by sputtering to a desired film thickness. Then, as shown in (b), the Al wiring layer 12 is etched into a desired pattern to form a wiring pattern (Al wiring pattern 25). After that, as shown in (c), while introducing oxygen gas into the chamber, by performing Al sputtering on the entire upper surface of the semiconductor substrate 1,
An Al oxide film 26 is formed on the entire upper surface of the semiconductor substrate 10. As a result, the Al oxide film 26, which is a metal oxide film, can be easily formed on the upper surface and the side surface of the Al wiring pattern 25 to have an arbitrary thickness.

Next, an embodiment of a semiconductor device formed by using the method for manufacturing a semiconductor device shown in FIG. 3 will be described with reference to FIG. However, the same components as those shown in FIG. 2 will be assigned the same reference numerals and detailed explanations thereof will be omitted. In the figure, 15 is a semiconductor substrate, 16 is an insulating film formed on the semiconductor substrate 15, 17 is a first-layer Al wiring layer formed on the insulating film 16, and 18 is a first-layer Al wiring layer 17 and Insulation film 1
Al oxide film formed on 6 and 19 is the first Al wiring layer 1
7 is an interlayer insulating film formed on 7, 20 is a second layer Al wiring layer formed on the interlayer insulating film 19, 21 is an Al oxide film formed on the second layer Al wiring layer 20, and 22 is This is a passivation film formed on the Al oxide film 21.

Reference numeral 23 is a separation layer that reaches the interlayer insulating film 19 from the insulating film 16 and divides the first-layer Al wiring layer 17 to form an Al wiring pattern 27. The inside of the separation layer 23 is made of an insulating material. Reference numeral 24 is a through hole for connecting the first-layer Al wiring layer 17 and the second-layer Al wiring layer 20, the inside of which is filled with Al as a wiring material.

In the embodiment shown in FIG. 4, after the first layer Al wiring layer 17 is formed, the separation layer 2 of the first layer Al wiring layer 17 is formed by a photolithography process and an etching process.
An opening reaching the insulating film 16 is formed at the location where 3 is formed. After that, while introducing oxygen gas into the chamber
Al sputtering is performed to form an Al oxide film 18 on the entire upper surface of the semiconductor substrate 10. As a result, the Al oxide film 18 which is a metal oxide film can be easily formed to an arbitrary thickness on the upper surface and the side surface of the Al wiring pattern 27 which is a wiring pattern.

In the embodiment, the metal oxide film is formed on the surface of the wiring layer or the wiring pattern. However, nitrogen gas or a mixed gas of oxygen and nitrogen is introduced instead of oxygen gas. A metal nitride film or a metal oxynitride film may be formed on the surface of the wiring layer or the wiring pattern.

[0024]

According to the method of manufacturing the semiconductor device of the first aspect, oxygen gas or the like is introduced into the chamber at the final stage of the sputtering step for forming the wiring layer, so that the upper surface of the wiring layer can be arbitrarily formed. Since it is possible to easily and efficiently form a metal oxide film or the like having the above thickness, the stress resistance of the wiring layer is improved, disconnection due to stress migration or the like can be prevented, and reliability can be improved.

According to the method of manufacturing a semiconductor device of the second aspect, by performing the sputtering process while introducing oxygen gas or the like, a metal oxide film or the like having an arbitrary thickness can be easily formed on the upper surface and the side surface of the wiring pattern. Since it can be formed efficiently, the stress resistance of the wiring pattern is improved, disconnection due to stress migration or the like can be prevented, and reliability can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a method for manufacturing a semiconductor device of the present invention.

FIG. 2 is a cross-sectional view showing an example of a semiconductor device formed by using the method for manufacturing the semiconductor device shown in FIG.

FIG. 3 is a cross-sectional view showing another embodiment of the method for manufacturing a semiconductor device of the present invention.

FIG. 4 is a cross-sectional view showing an example of a semiconductor device formed by using the method for manufacturing the semiconductor device shown in FIG.

FIG. 5 is a cross-sectional view showing an example of a conventional semiconductor device manufacturing method.

FIG. 6 is a cross-sectional view showing a different example of a conventional semiconductor device manufacturing method.

[Explanation of symbols]

 10, 15 semiconductor substrate 12 Al wiring layer (wiring layer) 14, 25, 27 Al wiring pattern (wiring pattern) 17 first layer Al wiring layer (wiring layer) 20 second layer Al wiring layer (wiring layer)

Claims (2)

[Claims] 1. A method of manufacturing a semiconductor device in which a wiring layer is formed on a semiconductor substrate, wherein an atmosphere of oxygen, nitrogen, or a mixed gas of oxygen and nitrogen is provided in a final step of a sputtering step for forming the wiring layer. Among them, the method for manufacturing a semiconductor device is characterized in that the wiring material to be deposited is oxidized or nitrided, or is sputtered while being nitrided and oxidized. 2. A method of manufacturing a semiconductor device for forming a wiring pattern on a semiconductor substrate, the wiring being deposited in the atmosphere of oxygen or nitrogen or a mixed gas of oxygen and nitrogen after forming the wiring pattern. A method of manufacturing a semiconductor device, wherein sputtering is performed while oxidizing, nitriding, or nitriding and oxidizing a material.