Semiconductor device manufacturing: process – Coating with electrically or thermally conductive material – To form ohmic contact to semiconductive material
Reexamination Certificate
2002-04-25
2004-08-03
Lebentritt, Michael S. (Department: 2824)
Semiconductor device manufacturing: process
Coating with electrically or thermally conductive material
To form ohmic contact to semiconductive material
C436S169000, C436S169000
Reexamination Certificate
active
06770557
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a method of fabricating a semiconductor device, and more specifically, it relates to a method of fabricating a semiconductor device improved to be capable of attaining high reliability in junction between a plug part and a wire part. The present invention also relates to a semiconductor device obtained by such a method.
2. Description of the Prior Art
FIG. 9
is a sectional view showing an ideally formed conventional dynamic random access memory.
A capacitor
11
is formed on a semiconductor substrate
50
. A metal wire
5
and lower conductor films
6
are connected with each other through plugs
3
embedded in contact holes
10
. The height of the capacitor
11
tends to increase due to high integration. Consequently, the contact holes
10
tend to increasingly deepen. The contact holes
10
are 0.3 &mgr;m to 0.4 &mgr;m in diameter, for example, and 1.5 &mgr;m to 2 &mgr;m in depth.
A fabrication process for a conventional semiconductor element such as the dynamic random access memory is described. In order to form contactors for the metal wire
5
and the lower conductor films
6
by the tungsten plugs
3
or the like, the contact holes
10
are first formed in an interlayer isolation film. Thereafter tungsten employed as the plug material is deposited and totally dryly etched back so that unnecessary tungsten part is removed, thereby forming the plugs
3
. Thereafter the metal wire
5
is formed on the plugs
3
as such.
If the dynamic random access memory is not ideally formed as shown in
FIG. 9
but any contact hole
10
is filled up with a plug material
2
as shown in
FIG. 10
, however, a cavity
20
may be defined in the plug material
2
.
When the plug material
2
having such a cavity
20
is etched back, the cavity
20
remains in the plug
3
as shown in FIG.
11
.
Referring to
FIG. 12
, when a portion located on such a cavity
20
is not covered with the metal wire
5
, i.e., when coverage is defective, a chemical solution (e.g., an organic solvent) employed in a wet step (a development step, a resist removal step or the like) for forming the metal wire
5
may penetrate into the cavity
20
to corrode the plug
3
. This problem remarkably arises when the metal wire
5
is misregistered.
The metal wire
5
and the plug
3
may not come into contact with each other due to such corrosion, leading to reduction of reliability of wiring. Further, the plug
3
may dissolve in the chemical solution and disappear, to reduce reliability of wiring.
SUMMARY OF THE INVENTION
The present invention has been proposed in order to solve the aforementioned problems, and an object thereof is to provide a method of fabricating a semiconductor device improved to be capable of attaining excellent contact between a metal wire and a plug thereby improving reliability of wiring.
Another object of the present invention is to provide a method of fabricating a semiconductor device improved to cause no disappearance of a plug.
Still another object of the present invention is to provide a semiconductor device improved in reliability of wiring, obtained by such a method.
In the method of fabricating a semiconductor device according to the present invention, an interlayer isolation film is first formed on a semiconductor substrate. A contact hole is formed in the aforementioned interlayer isolation film. A plug material is formed on the aforementioned semiconductor substrate to fill up the aforementioned contact hole. The aforementioned plug material is etched back thereby forming a plug in the aforementioned contact hole. The surface of a cavity defined in the aforementioned plug is covered with an insulator film. A metal wire is formed on the aforementioned interlayer isolation film to be in contact with the aforementioned plug.
According to a preferred mode of the present invention, the step of covering the surface of the cavity defined in the aforementioned plug with the insulator film includes a step of completely filling up the cavity formed in the aforementioned plug with the insulator film.
Alternatively, the step of covering the surface of the cavity defined in the aforementioned plug with the insulator film includes a step of covering the surface of the cavity without completely filling up the cavity formed in the aforementioned plug with the aforementioned insulator film.
The aforementioned insulator film preferably includes an SiN film.
This method is preferably applied to a method of fabricating a dynamic random access memory.
A semiconductor device according to another aspect of the present invention comprises a semiconductor substrate. An interlayer isolation film is formed on the aforementioned semiconductor substrate. A contact hole is formed in the aforementioned interlayer isolation film. A plug is formed in the aforementioned contact hole. The surface of a cavity defined in the aforementioned plug is covered with an insulator film. A metal wire is provided on the aforementioned interlayer isolation film to be in contact with the aforementioned plug.
According to a preferred mode of the present invention, the aforementioned insulator film completely fills up the aforementioned cavity.
According to another preferred mode of the present invention, the aforementioned insulator film does not completely fill up the aforementioned cavity
The aforementioned insulator film preferably includes an SiN film.
This semiconductor device includes a dynamic random access memory.
REFERENCES:
patent: 5262354 (1993-11-01), Cote et al.
patent: 5304510 (1994-04-01), Suguro et al.
patent: 5689140 (1997-11-01), Shoda
patent: 5872053 (1999-02-01), Smith
patent: 5985751 (1999-11-01), Koyama
patent: 6060386 (2000-05-01), Givens
patent: 6191027 (2001-02-01), Omura
patent: 6211085 (2001-04-01), Liu
patent: 6319821 (2001-11-01), Liu et al.
patent: 6410424 (2002-06-01), Tsai et al.
patent: 6576527 (2003-06-01), Nakamura
patent: 6-310605 (1994-11-01), None
patent: 95-30312 (1995-11-01), None
Lebentritt Michael S.
Renesas Technology Corp.
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