Equipment for forming a glue layer of an opening

Details Equipment for forming a glue layer of an opening Equipment for forming a glue layer of an opening

1998-10-19

2001-05-08

Bueker, Richard (Department: 1763)

Adhesive bonding and miscellaneous chemical manufacture

Differential fluid etching apparatus

With microwave gas energizing means

C204S192300

Reexamination Certificate

active

06228209

ABSTRACT:

CROSS-REFERENCE TO RELATED APPLICATION
This application claims the priority benefit of Taiwan application Ser. No. 87111777, filed Jul. 20, 1998, the full disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an equipment of semiconductor fabrication, and more particularly to an equipment for forming a glue layer over an opening in order to round an upper corner of the opening.
2. Description of Related Art
Currently, semiconductor devices are widely involved in many products and services in our daily life. All these semiconductor devices are fabricated on a wafer through many processes, such as photolithography, deposition, ion implantation, or etching, to form an integrated circuit (IC) device. One wafer usually includes a large number of IC devices.
In semiconductor fabrication on a wafer, or called a substrate, an opening with high aspect ratio, which is defined as a ratio of the depth to the width, is needed in some situations. The opening, such as a via opening or a contact opening, is formed in a dielectric layer and is filled with a metallic material, such as tungsten, to form a metal plug. The dielectric layer is usually sandwiched between two metal layers or between one metal layer on the top and the substrate on the bottom. The purpose of the metal plug is to interconnect these two metal layers for an interconnection between device elements. Since the material properties of the metal plug and the dielectric layer are different, there usually is a poor adhesion between them at the sidewall of the opening. In order to improve the adhesion between the metal plug and the dielectric layer, a conformal glue layer, or called barrier layer, is usually formed over the opening before the metal plug is filled into the opening. The glue layer can improve adhesion of the metal plug in the dielectric layer.
Currently, the glue layer typically includes a mix layer of titanium and titanium nitride as shown in FIG.
1
A and
FIG. 1B
, which are cross-sectional views, illustrating a fabrication process of an conventional opening plug. In
FIG. 1A
, a dielectric layer
102
is formed on a substrate
100
. An opening
104
is formed in the dielectric layer
102
. A titanium layer
106
is formed over the substrate
100
by physical vapor deposition (PVD) and a titanium nitride layer
108
is formed over the titanium layer
106
by chemical vapor deposition (CVD). The titanium layer
106
and the titanium nitride layer
108
form together as a glue layer, which is conformal to the substrate
100
. Since a high integration IC device is desired, the aspect ratio of the opening is usually high, which degrades the step coverage performance. The titanium layer
106
formed by PVD may have an overhang
106
a
at each upper corner
102
a
of the opening
104
.
In
FIG. 1B
, a tungsten metal layer
110
is formed over the substrate
100
to fill the opening
104
of FIG.
1
A. Since the existence of the overhang
106
a
, the step coverage performance is also poor. A void
112
is formed within the opening
104
. The void
112
can induce some problems, such as current leakage, and cause a failure of the device.
The fabrication processes described above are performed in a fabrication equipment.
FIG. 2
is a schematic drawing of a conventional fabrication equipment for metallization process. In
FIG. 2
, the substrate (not shown) is put in a load/unload chamber
202
. The substrate, sequentially following the arrow direction
204
, is put in a degas chamber
206
to remove remaining water vapor on the substrate, in a sputtering chamber
208
to form the opening, in a PVD chamber
210
to deposit the titanium layer
106
of
FIG. 1B
, and in a CVD chamber
212
to deposit the titanium layer
108
of FIG.
1
B.
In this conventional fabrication equipment, there is no chamber for removing the overhang
106
a
of FIG.
1
B. If the overhang
106
is not removed, the step coverage performance on the opening
104
is then not improved.
SUMMARY OF THE INVENTION
It is therefore an objective of the present invention to provide a fabrication equipment to form an opening plug, which includes a glue layer without an overhang structure on each upper sharp corner of the opening. A void inside the opening plug is effectively avoided.
It is another an objective of the present invention to provide a fabrication equipment to form an opening plug. The equipment allows a portion of the glue layer on the upper sharp corner of the opening to be rounded so as to improve step coverage performance for a high aspect ratio opening.
In accordance with the foregoing and other objectives of the present invention, a fabrication equipment to form an opening plug is provided. The equipment at least includes a load/unload chamber, an usual sputtering chamber, a radio frequency (RF) sputtering chamber, a physical vapor deposition (PVD) chamber, and a chemical vapor deposition (CVD). The load/unload chamber is used to load a substrate. The usual sputtering chamber is used to form an opening on the substrate. The PVD chamber is used to form a first glue layer. The RF sputtering chamber is used to remove an overhang structure on the first glue layer. The CVD chamber is used to form a second glue layer over the first glue layer. The RF sputtering chamber is the main characteristic of the invent so as to improve a step coverage performance. Moreover, in order to avoid moisture to deteriorate the fabrication, a degas chamber is preferable further included before starting the usual sputtering chamber to remove moisture remaining on the substrate before fabrication.


REFERENCES:
patent: 5135608 (1992-08-01), Okutani
patent: 5667592 (1997-09-01), Boitnott et al.
patent: 5882488 (1999-03-01), Leiphart

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