JPH0945685A - Manufacture of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple manufacturing method for a semiconductor device which is provided with a fine interconnection. SOLUTION: A silicon oxide film 2 is formed on a silicon substrate 1, the silicon oxide film 2 is patterned, and trenches 2a are formed. Then, an aluminum film 3 is deposited on the whole face of a device by using a high-temperature sputtering method. In succession, a resist pattern 4 is used as a mask for ion implantation, and oxygen ions are implanted into the surface of the aluminum film 3 while a laser beam is being irradiated. Then, a region into which the oxygen ions have been implanted in the aluminum film 3 is oxidized so as to be changed into an alumina film 5. At this time, since the oxygen ions are not implanted into the aluminum film 3 directly under the resist pattern 4, the aluminum film 3 is left as it is.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of manufacturing a semiconductor device having a multi-layer wiring.

[0002]

2. Description of the Related Art In recent years, multi-layer wiring technology has become more and more important with the high integration of LSI. The present applicant has filed Japanese Patent Publication No. 59-27099 (IPC; H01L21 / 94, H01L21 / 90).
The method of forming a multilayer wiring disclosed in (1) has already been put to practical use.

[0003]

In the multi-layer wiring technology, it is important to facilitate the patterning of the wiring in the step portion of the pattern caused by the multi-layering and prevent the disconnection. For that purpose, the device surface must be flattened. The need for this flattening technique increases as the wiring becomes finer.

At the time when the above publication was disclosed, it was not necessary to miniaturize the wiring as required in recent years. Therefore, the above publication does not describe any flattening technique. Also, when forming fine wiring,
The description of the publication has the following problems.

(1) At column 2, line 11 of the above publication, it is stated that a metal film is provided by vapor deposition. At the time when the above-mentioned publication was disclosed, generally speaking, vapor deposition was a vacuum vapor deposition method. However, since the step coverage of the vacuum deposition method is low, there is a problem that it is difficult to form fine wiring.

(2) At column 2, line 15 of the above publication, it is stated that the surface of the metal film is anodized into alumina. Anodization is a method of oxidizing the surface of a metal film by applying an electric field to the metal film in an electrolytic solution or plasma using an anode and a cathode and moving the metal ions toward the anode by the electric field. Is. However, anodization has a problem that it is difficult to form fine wiring. Further, anodization is not a technique generally used in the LSI manufacturing process. Therefore, it is necessary to newly introduce an apparatus for performing anodic oxidation into the production line, which causes a problem of increased production cost.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a simple manufacturing method of a semiconductor device having fine wiring. Another object of the present invention is to provide a simple manufacturing method of a semiconductor device having fine multilayer wiring.

[0008]

The invention according to claim 1 comprises a step of forming a conductive film and a step of changing a desired portion of the conductive film into an insulator by a desired film thickness. Is the gist.

According to a second aspect of the present invention, a wiring layer made of a conductive film is formed by forming a flat conductive film and changing a desired portion of the conductive film into an insulator by a desired film thickness. And a step of simultaneously forming a flat interlayer insulating film made of an insulating material.

According to a third aspect of the present invention, a step of forming a trench on the substrate, a step of forming a flat conductive film on the entire surface of the substrate including the inside of the trench, and a desired portion of the conductive film in the trench are formed. By changing to an insulator up to the depth reaching the upper edge of the conductive film of, the lower layer wiring made of the conductive film in the trench, the upper layer wiring made of the conductive film in the trench, and the flat interlayer insulating film made of the insulating material. The gist of the invention is to have a step of simultaneously forming and.

According to a fourth aspect of the invention, in the method of manufacturing a semiconductor device according to any one of the first to third aspects,
The conductive film is made of a material that changes into an insulator when oxidized, and the step of changing the conductive film into an insulator is to use a method of implanting oxygen ions into the surface of the conductive film.

According to a fifth aspect of the present invention, in the method of manufacturing a semiconductor device according to any one of the first to third aspects,
The conductive film is made of a material that changes into an insulator when oxidized, and the process of changing the conductive film into an insulator uses a method of implanting oxygen ions while irradiating the surface of the conductive film with a laser beam. To do.

According to a sixth aspect of the present invention, in the method of manufacturing a semiconductor device according to any one of the first to third aspects,
The conductive film is made of a material that changes into an insulator when oxidized, and the step of changing the conductive film into an insulator is to use a method of irradiating the surface of the conductive film with a laser beam in an oxidizing atmosphere.

According to a seventh aspect of the present invention, in the method of manufacturing a semiconductor device according to any one of the first to third aspects,
The conductive film is made of a material that changes to an insulator when it is nitrided, and the step of changing the conductive film to an insulator is to use a method of implanting nitrogen ions into the surface of the conductive film.

The invention described in claim 8 is the method for manufacturing a semiconductor device according to any one of claims 1 to 3,
The conductive film is made of a material that changes into an insulator when nitrided, and the process of changing the conductive film into an insulator uses a method of implanting nitrogen ions while irradiating a laser beam on the surface of the conductive film. To do.

According to a ninth aspect of the present invention, in the method of manufacturing a semiconductor device according to any one of the first to third aspects,
The conductive film is made of a material that changes to an insulator when it is nitrided, and the gist of the process of changing the conductive film to an insulator is to use a method of irradiating the surface of the conductive film with a laser beam in a nitriding atmosphere.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The manufacturing method of each embodiment embodying the present invention will be described below with reference to FIG. (First Embodiment) Step 1 (see FIG. 1A); an appropriate method (thermal oxidation method, C
A silicon oxide film 2 (film thickness: 600 nm) is formed on a silicon substrate 1 by using the VD method or the PVD method. Next, the silicon oxide film 2 is patterned by using the photolithography technique to form the trench 2a.

Step 2 (see FIG. 1B): An aluminum film 3 is deposited on the entire surface of the device using a high temperature sputtering method. still,
The thickness of the aluminum film 3 is 60 on the silicon oxide film 2.
It is controlled to be 0 nm. Next, a resist pattern 4 is formed on the aluminum film 3.

Step 3 (see FIG. 1C): Using the resist pattern 4 as a mask for ion implantation, oxygen ions are implanted while irradiating the surface of the aluminum film 3 with a laser beam. The oxygen ion implantation conditions are such that the depth reaching the upper edge of the aluminum film 3 in the trench 2a (specifically, the aluminum film 3
It is set so that oxygen ions reach from the surface to a depth of about 660 to 720 nm). By this treatment, the region of the aluminum film 3 into which oxygen ions are implanted is oxidized and changed into the alumina film 5. At this time, oxygen ions are not implanted into the aluminum film 3 directly below the resist pattern 4, so that the aluminum film 3 remains as it is. Further, since oxygen ions are not implanted into the aluminum film 3 in the trench 2a except the upper edge portion thereof, the aluminum film 3 is left as it is. Therefore, the aluminum film 3 (see FIG.
The alumina film 5 insulates a) from the trench 2a below the aluminum film 3 and the aluminum film 3 (shown in FIG. 3b) in the trench 2a adjacent to the trench 2a.

Step 4 (see FIG. 1D): The resist pattern 4 is removed. As a result, a two-layer wiring structure including the lower layer wiring made of the aluminum film 3 in the trench 2a and the upper layer wiring made of the aluminum film 3 immediately below the resist pattern 4 is completed.

According to the manufacturing method of this embodiment, the following actions and effects can be obtained. In step 2, since the step coverage of the high temperature sputtering method is high, the inside of the trench 2a can be completely filled with the aluminum film 3. Therefore, even if the width of the trench 2a is narrowed, the inside of the trench 2a can be surely filled with the aluminum film 3, and the lower layer wiring made of the aluminum film 3 in the trench 2a can be miniaturized.

In step 2, in the high temperature sputtering method,
Since the deposited aluminum film 3 is reflowed, the surface coverage of the aluminum film 3 can be flattened together with the high step coverage. Therefore, the resist pattern 4 having high dimensional accuracy can be easily formed. Therefore, the width of the resist pattern 4 can be narrowed, and the upper wiring formed of the aluminum film 3 directly below the resist pattern 4 can be miniaturized.

Since the surface of the aluminum film 3 is flat, the surface of the alumina film 5 is also flat. Therefore, when the third layer wiring is formed on the aluminum film 3 and the alumina film 5,
In addition to facilitating patterning of the third-layer wiring, disconnection can be prevented. Therefore, the third layer wiring can be miniaturized. In other words, a flat interlayer insulating film made of the alumina film 5 can be obtained.

In step 3, the resist pattern 4 is used as a mask for ion implantation and oxygen ions are implanted while irradiating a laser beam. Therefore, the temperature of the aluminum film 3 is not increased unnecessarily, and the alumina film 5
Can be formed with high dimensional accuracy. In particular, since the film thickness of the alumina film 5 is equal to the implantation depth of oxygen ions, the film thickness of the alumina film 5 can be freely controlled by adjusting the oxygen ion implantation conditions. As a result, in combination with the above action and effect, the resist pattern 4
It is possible to easily miniaturize the upper layer wiring formed of the aluminum film 3 immediately below.

(Second Embodiment) Step 1 (see FIG. 1A): The same as Step 1 of the first embodiment. Step 2 (see FIG. 1B): An aluminum film 3 is deposited on the entire surface of the device by using a high temperature sputtering method. Next, aluminum film 3
A reflection film 11 for laser light is formed on the top. As the reflection film 11 for the laser light, any material may be used as long as it has a higher reflectance for the laser beam used in step 3 than the aluminum film 3.

Step 3 (see FIG. 1C): The surface of the aluminum film 3 is irradiated with a laser beam in an oxidizing atmosphere. Then, the aluminum film 3 irradiated with the laser beam is oxidized and changed to the alumina film 5. At this time, since the laser beam is not applied to the aluminum film 3 directly below the laser light reflection film 11, the aluminum film 3 is left as it is.

Step 4 (see FIG. 1D): The reflection film 11 for laser light is removed. According to the manufacturing method of the present embodiment,
The same action and effect as can be obtained. Further, in the manufacturing method of the present embodiment, since it is only necessary to irradiate the laser beam in the oxidizing atmosphere in step 3, it is not necessary to use the oxygen ion implantation device as in the first embodiment, and the structure of the manufacturing device Can be easy. However,
The controllability of the film thickness of the alumina film 5 is lower than that of the first embodiment.

The above embodiments may be modified as follows, and the same operation and effect can be obtained in such a case. (1) In step 2, the high temperature sputtering method is replaced with another PVD method (ion plating method, which has high step coverage).
Ion beam deposition method, cluster ion beam method, etc.) In this case, if the PVD method is performed at a high temperature, the deposited aluminum film 3 can be reflowed, and the surface of the aluminum film 3 can be further flattened as in the above-described embodiments.

(2) In step 2, after the aluminum film 3 is formed, further heat treatment is performed to reflow the aluminum film 3. In this case, the surface of the aluminum film 3 can be further flattened. Further, after the aluminum film 3 is formed by the room temperature sputtering method, heat treatment is performed to reflow the aluminum film 3.

(3) In step 2, after the aluminum film 3 is formed, the surface of the aluminum film 3 is flattened by the CMP (Chemical Mechanical Polishing) method. (4) After forming a lower layer wiring made of a tungsten plug in the trench 2a, an aluminum film 3 is deposited on the entire surface of the device. Then, by replacing a desired portion of the aluminum film 3 with the alumina film 5, an upper layer wiring made of the aluminum film 3 and an interlayer insulating film made of the alumina film 5 are formed. That is,
As in the above-described embodiments, the upper and lower two-layer wiring is not formed by the aluminum film 3, but only the upper wiring is formed by the aluminum film 3. In this case, since the device surface is flattened by the tungsten plug, it is not necessary to consider the step coverage when depositing the aluminum film 3. Therefore, for forming the aluminum film 3, an appropriate PV including a vacuum deposition method is used.
Method D can be used.

(5) After the lower wiring and the interlayer insulating film are formed by the recess wiring method, the aluminum film 3 is deposited on the entire surface of the device, and a desired portion of the aluminum film 3 is replaced with the alumina film 5. An upper layer wiring made of 3 and an interlayer insulating film made of an alumina film 5 are formed.

(6) It is applied to the formation of single-layer wiring instead of multilayer wiring. (7) A conductive film made of an appropriate material that changes into an insulator when the aluminum film 3 is oxidized (various metals such as copper, gold and silver, various refractory metals such as tungsten and titanium, doped polysilicon, metal silicide) Etc.).

(8) The aluminum film 3 is replaced with a conductive film (doped polysilicon, metal silicide, etc.) made of an appropriate material that changes into an insulator when nitrided. in this case,
In the first embodiment, oxygen ions are replaced with nitrogen ions, and in the second embodiment, the oxidizing atmosphere is replaced with a nitriding atmosphere.

(9) The silicon oxide film 2 is replaced with another appropriate insulating film (silicon nitride film, silicate glass film, SOG film, etc.). Although the embodiments have been described above, technical ideas other than the claims that can be grasped from the embodiments will be described below along with their effects.

(A) In the method of manufacturing a semiconductor device according to claim 3, the step of forming the trench on the substrate includes a step of forming an insulating film on the entire surface of the substrate and a step of patterning the insulating film. A method of manufacturing a semiconductor device including.

(B) A method of manufacturing a semiconductor device according to claim 4, including the step of reflowing the conductive film by performing the method of forming the conductive film at a high temperature.

(C) A step of forming a trench on the substrate, a step of forming and filling a metal plug in the trench, a step of forming a flat conductive film on the entire surface of the device,
And a step of changing a desired part of the conductive film into an insulator.

(D) a step of forming a lower layer wiring and an interlayer insulating film on the substrate; and a step of forming an upper layer wiring and an interlayer insulating film by using the method of manufacturing a semiconductor device according to claim 1 or 2. A method for manufacturing a semiconductor device comprising:

By the way, in the present specification, the conductive film is not limited to an aluminum film, but a conductive film made of an appropriate material that changes into an insulator when oxidized (various metals such as copper, gold and silver, tungsten, titanium, etc.). Various refractory metals, doped polysilicon, metal silicide, etc.) or a conductive film (doped polysilicon, metal silicide, etc.) made of an appropriate material that changes to an insulator when nitrided.

[0040]

As described in detail above, according to the present invention, it is possible to provide a simple manufacturing method of a semiconductor device having fine wiring. Another object of the present invention is to provide a simple method for manufacturing a semiconductor device having fine multilayer wiring.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view for explaining a manufacturing process of each embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Substrate 2 ... Silicon oxide film 2a ... Trench 3 ... Aluminum film as a conductive film 5 ... Alumina film as an insulator

Claims (9)

[Claims] 1. A method of manufacturing a semiconductor device, comprising: a step of forming a conductive film; and a step of changing a desired portion of the conductive film into an insulator by a desired film thickness. 2. A step of forming a flat conductive film and a step of changing a desired portion of the conductive film into an insulator by a desired film thickness to thereby form a wiring layer made of the conductive film and a flat layer made of the insulator. A method of manufacturing a semiconductor device, comprising the step of simultaneously forming an interlayer insulating film. 3. A step of forming a trench on a substrate, a step of forming a flat conductive film on the entire surface of the substrate including the inside of the trench, and a desired portion of the conductive film being an upper edge portion of the conductive film in the trench. A step of simultaneously forming a lower layer wiring made of a conductive film in the trench, an upper layer wiring made of a conductive film on the trench, and a flat interlayer insulating film made of an insulating material by changing to an insulator to a depth reaching A method for manufacturing a semiconductor device comprising: 4. The method of manufacturing a semiconductor device according to claim 1, wherein the conductive film is made of a material that changes into an insulator when oxidized, and the step of changing the conductive film into an insulator is performed. , A method of manufacturing a semiconductor device using a method of implanting oxygen ions into the surface of a conductive film. 5. The method of manufacturing a semiconductor device according to claim 1, wherein the conductive film is made of a material that changes into an insulator when oxidized, and the step of changing the conductive film into an insulator is performed. , A method for manufacturing a semiconductor device using a method of implanting oxygen ions while irradiating a surface of a conductive film with a laser beam. 6. The method of manufacturing a semiconductor device according to claim 1, wherein the conductive film is made of a material that changes into an insulator when oxidized, and the step of changing the conductive film into an insulator is performed. A method for manufacturing a semiconductor device using a method of irradiating a surface of a conductive film with a laser beam in an oxidizing atmosphere. 7. The method of manufacturing a semiconductor device according to claim 1, wherein the conductive film is made of a material that changes into an insulator when nitrided, and the step of changing the conductive film into an insulator is performed. , A method for manufacturing a semiconductor device using a method of implanting nitrogen ions into the surface of a conductive film. 8. The method of manufacturing a semiconductor device according to claim 1, wherein the conductive film is made of a material that changes into an insulator when nitrided, and the step of converting the conductive film into an insulator is performed. , A method for manufacturing a semiconductor device using a method of implanting nitrogen ions while irradiating a surface of a conductive film with a laser beam. 9. The method of manufacturing a semiconductor device according to claim 1, wherein the conductive film is made of a material that changes into an insulator when nitrided, and the step of changing the conductive film into an insulator is performed. A method for manufacturing a semiconductor device using a method of irradiating a surface of a conductive film with a laser beam in a nitriding atmosphere.