JPH06151603A - Production of semiconductor device - Google Patents

Abstract

PURPOSE:To fit a conductive member in a contact hole or through hole without disconnecting a line and to easily and surely form a flat multilayer interconnection. CONSTITUTION:A contact hole 3 is formed on an insulated film 2 on a base 1, and it is fit halfway by depositing a patterned conductive member 4 over it. A mask film 5 is formed on the contact hole 3 to completely cover it, and then an etching treatment removes a conductive member 4c over the insulating film 2. This reveals the insulating film 2 at the height of the conductive member 4 fit in the hole 3. Thus, the contact hole 3 can be fit with the conductive member 4 and the surface of the conductive member 4 can be made flat.

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.

[0002]

2. Description of the Related Art In recent years, in order to increase the degree of integration of semiconductor integrated circuits, the need for a multi-layered wiring structure having three or more layers has become stronger and stronger. On the other hand, it is difficult to form a multilayer wiring flat with the miniaturization of contact holes and through holes, and disconnection occurs because the multilayer wiring is not formed flat.
It is a serious factor that lowers the yield.

2A to 2E are views showing an example of a typical conventional manufacturing process of a semiconductor device intended to prevent disconnection. Referring to FIGS. 2A to 2E, first, a PSG film 12 is deposited as an insulating film on a silicon substrate 11 (FIG. 2A), and then a resist film 13 is applied thereon to form a contact. The window 14 is opened corresponding to the hole (FIG. 2 (b)). Here, first, isotropic dry etching is performed to remove the step 15 at the contact hole opening (FIG. 2C), and then anisotropically dry etching is performed to form a vertical hole (FIG. 2C). 2 (d)). After that, the resist film 13 is removed, and, for example, aluminum (Al) is deposited on the entire surface as a wiring material, so that the wiring 16 as shown in FIG. 2E can be formed.

By the way, in this manufacturing process example, FIG.
As shown in (e), although the possibility of disconnection can be certainly reduced, the opening diameter A of the contact hole becomes larger than the hole diameter at the design stage, and the contact hole should be formed finely. Becomes difficult. As described above, in the above example of the manufacturing process, the demand for miniaturization of the contact hole accompanying the miniaturization of the integrated circuit and the demand for preventing disconnection of the multilayer wiring are incompatible with each other.

In order to solve such a problem, Japanese Patent Publication No. 4-1498 discloses that a conductor material is embedded with its surface flattened while keeping the shape of a through hole, and wiring is formed on the conductor material. Methods have been proposed for forming layers flat.
3A to 3E are views showing the manufacturing process disclosed in this publication. With reference to FIGS. 3A to 3E, in this method, a through hole 23 is first formed in the insulating film 22 on the semiconductor substrate 21 (FIG. 3A). Then, the conductor material 24a is first deposited on the entire surface of the substrate 21 by vapor deposition, and then the conductor material 24b is deposited by sputtering to fill the through-holes 23 (FIG. 3B). Then, the through hole 23 is provided on the upper portion of the through hole 23.
A mask film 25 having a width larger than that of the mask film 25 is formed (FIG. 3).
(C)). Next, the conductor materials 24a and 24b on the insulating film 22 are removed by etching (FIG. 3D),
After that, the mask film 25 is removed. As a result,
It is intended that the conductor material 24 is embedded in the through-hole 23 as shown in (e) and that the upper surface of the conductor material 24 is kept flat.

[0006]

However, in the method disclosed in the above-mentioned publication, when the through hole is buried, that is, in the step of FIG. Body material 24a, 24
When b is sequentially deposited and the sputtering method is used, the conductive material has the property of depositing not only on the bottom of the through-hole but also on the side, so that FIGS. The process to be manufactured as shown in FIG.
It becomes like. That is, as shown in FIG. 4B, when the conductor material 24b is deposited by sputtering, the conductor material 24b in the through hole 23 is the conductor material 24b outside the through hole, that is, the insulating film. There is a possibility that it will be connected to the conductor material 24b on 22.
In this case, the mask film 25 is formed in the step of FIG.
Isotropically etching the conductive material 24 on the lower side of the conductive material 24, the conductive material 24 in the through hole is etched, and the flatness of the upper surface of the conductive material is flat as shown in FIG. 4 (e). However, there is a drawback in that it causes disconnection of wiring and poor contact.

The present invention solves the above-mentioned drawbacks of the prior art. It embeds a conductive material in the contact hole or through hole without causing wire breakage, and provides a simple and reliable flat surface. It is an object of the present invention to provide a method for manufacturing a semiconductor device capable of forming multi-layer wiring.

[0008]

In order to achieve the above object, the present invention is to form a contact hole or a through hole on an insulating film on a substrate and then deposit a conductive material on the entire surface. And depositing the contact hole or through hole halfway, and forming a mask film on the contact hole or through hole so as to completely cover the contact hole or through hole. The method is characterized by including a step of forming, a step of removing the conductive material on the insulating film by etching, and a step of etching back the insulating film to the height of the conductive material embedded in the hole. . This allows the contact
The conductor or the through hole can be embedded with a conductive material, and the upper surface of the conductive material can be formed to be flat.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1A to 1G are views showing an example of a manufacturing process of a semiconductor device according to the present invention. Referring to FIGS. 1A to 1G, first, as shown in FIG.
A PSG film 2 having a film thickness of 10000Å is deposited on a silicon substrate 1, and a contact hole 3 having a diameter of 1.0 μm is vertically formed by reactive ion etching. Next, as shown in FIG. 1B, Al (aluminum) is deposited as a conductor material by a resistance heating method (vapor deposition) to a film thickness of 7,000 Å to form an Al conductor material layer 4. In addition,
In this step, the conductor material layer 4 is contacted with the contact hole.
It is partially embedded in the rule 3, and therefore the contact hole
There is no connection between the inside of rule 3 and the outside of contact hole 3.
Next, a resist is applied on the entire surface to a thickness of about 1 .mu.m, and patterning is performed as shown in FIG.
Resist film 5 having a width about twice (2 μm) the diameter of the rule 3
To form. That is, the resist film 5 is formed so as to completely cover the contact hole 3.

Next, the conductor material layer 4 (4c) of Al formed outside the contact hole 3 is removed by isotropic wet etching with a phosphoric acid type etchant.

Then, as shown in FIG. 1D, the PSG is left with the resist film 5 left until the height is the same as the surface of the conductive material layer 4 embedded in the contact hole 3.
Isotropic dry etching is performed on the film 2 to remove a part 2d of the PSG film 2.

After that, when the resist film 5 is removed, as shown in FIG. 1E, the upper surface of the conductor material layer 4 in the contact hole 3 and the surface of the PSG film 2 are flush with each other. The upper surface of the conductor material layer 4 can be formed to be substantially flat. Next, a conductor material layer 4f of Al is deposited by sputtering to form an electrode wiring, and the surface of the conductor material layer 4f is also formed flat because the base is flat (FIG. 1 (f)). By depositing Al by sputtering in the step of FIG. 1F, the oxide film slightly present on the surface of the conductor material layer 4 in the contact hole 3 can be removed by reverse sputtering, which is favorable. An Al-Al contact is obtained.

In the case of forming a multilayer wiring structure, a PSG film 6 is further formed on the conductor material layer 4f, and the PSG film 6 is formed.
The through hole 7 may be formed in the substrate, the Al conductor material layer 8 may be formed by the same method as described above, and then the Al conductor material layer 8g may be formed (FIG. 1G).

Although Al is used as the conductor material and the PSG film is used as the insulating film in the above-described embodiments, other conductor materials or insulating film materials may be used. In that case, it is necessary to appropriately change the etchant and the etching method.

[0015]

As described above, according to the present invention, after forming a contact hole or a through hole in an insulating film on a substrate, a conductive material is deposited on the entire surface by vapor deposition to form the contact hole or the through hole. The through hole is embedded partway, and then the contact hole or through hole is placed on top of the contact hole or through hole.
A mask film is formed so as to completely cover the insulating film, and then the conductive material on the insulating film is removed by etching to etch back the insulating film to the height of the conductive material embedded in the hole. However, when the contact hole or the through hole is buried, the conductive material is buried by vapor deposition and only up to the middle of the contact hole or the through hole. The conductor material is not connected to the inside and outside of the hole. Therefore, it is possible to easily and surely form a flat wiring without causing the problems in the prior art. As a result, even when the contact hole or the through hole is miniaturized with the miniaturization of the integrated circuit, a reliable flatness can be achieved without impairing the demand for the miniaturization of the contact hole or the through hole. It is possible to form various multilayer wiring. As a result, it is possible to easily realize a semiconductor device having a multilayer wiring structure and provide a good semiconductor device without impairing its reliability even when the degree of integration of the semiconductor device is increased.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a manufacturing process of a semiconductor device according to the present invention.

FIG. 2 is a diagram showing an example of a conventional manufacturing process of a semiconductor device.

FIG. 3 is a diagram showing a conventional manufacturing process example of a semiconductor device.

FIG. 4 is a diagram showing an example of a conventional manufacturing process of a semiconductor device.

[Explanation of symbols]

 1 Silicon Substrate 2 PSG Film 3 Contact Hole 4, 8 Conductor Material Layer 5 Resist Film 6 PSG Film 7 Through Hole

Claims (1)

[Claims] 1. A contact hole or a through hole is formed on an insulating film on a substrate, and then a conductive material is deposited on the entire surface by vapor deposition so that the contact hole or the through hole is partially formed. Step of burying, step of forming mask film on contact hole or through hole so as to completely cover contact hole or through hole, step of removing conductive material on insulating film by etching And a step of etching back the insulating film up to the height of the conductive material embedded in the hole.