Coating processes – Direct application of electrical – magnetic – wave – or... – Pretreatment of coating supply or source outside of primary...
Reexamination Certificate
1997-07-07
2003-08-19
Padgett, Marianne (Department: 1762)
Coating processes
Direct application of electrical, magnetic, wave, or...
Pretreatment of coating supply or source outside of primary...
C427S574000, C427S579000, C427S575000, C438S789000
Reexamination Certificate
active
06607790
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method of forming a thin film for a semiconductor device, and, more particularly, to a plasma-enhanced chemical vapor deposition (CVD) method for forming a thin film on the surface of a body, such as a semiconductor substrate.
BACKGROUND OF THE INVENTION
One method which has been used to form a thin film on the surface of a body, such as a semiconductor substrate, is the plasma-enhanced chemical vapor deposition (CVD) technique. In this technique, the body is placed in a reaction chamber and a reaction gas is introduced into the chamber. The gas is activated by means of a plasma discharge created in the chamber. This causes the reaction gas to react and deposit a thin film of a material on the surface of the body.
The methods that have been used on a practical basis for the purpose of creating a plasma in a reaction chamber for plasma-enhanced CVD include a method in which an electrical power source with a frequency of 13.56 MHz or 400 KHz, or the like, is applied to a pair of opposed electrodes which are within the reaction chamber. The speed of deposition and the quality of the deposited thin film are controlled by adjusting the power of this electrical power source. Another method of creating the plasma in the reaction chamber uses a microwave radiation of 1.54 GHz which is introduced into the reaction chamber by means of a wave guide. This method is known as ECR plasma CVD. In the plasma enhanced CVD techniques, gases such as tetraethylorthosilicate (TEOS) gas and silane (SiH
4
) have been used as reaction gases to cause a thin film of SiO or SiON to deposit on the surface of a semiconductor substrate.
With the recent development of high density semiconductor integrated circuit devices (VLSIs), there has been created a crucial need for techniques that can create ultrafine configurations in the submicron range. In order to respond to this demand, the possibility of using conventional techniques to create submicron configurations was considered by conducting an empirical study on the configuration of thin films produced by conventional plasma-enhanced CVD methods.
Referring to FIGS.
1
(
a
) to
1
(
f
), there is shown sectional views of semiconductor devices
10
a-
10
f
comprising a substrate
12
a-
12
f
having a layer
14
a-
14
f
of an insulating material, such as silicon dioxide, on a surface
16
a-
16
f
thereof. A plurality of spaced, parallel strips
18
a-
18
f
of a conductive material, such as aluminum, are on the insulating layer
14
a-
14
f,
and are coated with a layer
20
a-
20
f
of an insulating material, such as silicon dioxide. The conductive strips
18
a-
18
f
are of different widths with the strip
18
a
being the widest and the strip
18
f
being the narrowest. Also, the spacing between the conductive strips
18
a-
18
f
vary with the strips
18
a
being spaced apart the greatest distance and the strips
18
f
being spaced apart the closest distance. The insulating coatings
20
a-
20
f
were formed by a conventional plasma-enhanced CVD (referred to hereinafter as “PECVD”) wherein a reaction gas of SiH
4
was introduced in a reaction chamber and a plasma was created in the reaction chamber by applying a single 13.56 MHz high-frequency electrical power source between a pair of opposing electrodes in the chamber. As can be seen in FIGS.
1
(
a
) to
1
(
f
), the sides of the silicon dioxide coating
20
a-
20
f
have a cross-sectional configuration formed so as to posses roundness in the form of protrusions. More specifically, the thin film
20
a-
20
f
near the upper side of the aluminum strip
18
a-
18
f
is thicker than the portion of the coating
20
a-
20
f
near the bottom of the aluminum strip
18
a-
18
f.
This results in the problem of gaps being created near the bottom of the aluminum strips
18
a-
18
f.
This is especially serious in high-density strips (wiring) on the submicron level, where the gap spacing between the aluminum strips is reduced as shown in FIGS.
1
(
e
) and
1
(
f
).
Referring to
FIGS. 2A
to
2
F, there are shown sectional views of a semiconductor device
22
a-
22
f
which is similar to the semiconductor device
10
a-
10
f
of
FIGS. 1A
to
1
F. The semiconductor device
22
a-
22
f
comprises a substrate
24
a-
24
f
of a semiconductor material, such as silicon, having a layer
26
a-
26
f
of an insulating material, such as silicon dioxide, on a surface
28
a-
28
f
thereof. A plurality of spaced, parallel strips
30
a-
30
f
of a conductive material, such as aluminum, are on the insulating layer
26
a-
26
f.
The conductive strips
30
a-
30
f
are coated with a layer
32
a-
32
f
of an insulating material, such as silicon dioxide. The conductive strips
30
a-
30
f
are of different widths, with the conductive strip
30
a
being the widest and the conductive strip
30
f
being the narrowest. Also, the spacing between the conductive strips
30
a-
30
f
varies with the conductive strips
30
a
being spaced apart the greatest distance and the conductive strips
30
f
being spaced apart the least distance.
The insulating coatings
32
a-
32
f
were formed by PECVD using tetraethylorthosilicate (TEOS) as the reaction gas. The plasma was created in the reaction chamber by simultaneously applying a 13.56 MHz high-frequency electrical power source and a 400 kHz low-frequency electrical power source between opposing electrodes in the chamber. When these electrical power sources of two frequencies are utilized, it is possible to enhance the quality of the thin film and the speed with which it is created.
As can be seen from
FIGS. 2A
to
2
F, the configuration of the sidewalls of the silicon dioxide thin film
32
a-
32
f
has little or no curvature when compared to the configuration of the silicon dioxide thin films
20
a-
20
f
shown in
FIGS. 1A
to
1
F. Thus, this technique can be said to make a major contribution to enhancing the control of the formed thin film. However, as is shown in FIGS.
5
(
e
) and
5
(
f
), the reduction in the gaps is insufficient in the creation of high density thin films in the submicron range at which the distance between the aluminum strips
30
e
and
30
f
decreases. Also, it is difficult with the above conventional techniques to respond to the demand for the creating of higher densities. Therefore, it is desirable to have a method of depositing a thin film for a semiconductor device than will provide good coatings even with high density devices.
SUMMARY OF THE INVENTION
The present invention is directed to a method of forming a thin film on a substrate of a semiconductor device wherein the substrate is subjected to a mixture of tetraethylorthosilicate gas and a halogen gas, and a plasma is formed by means of a plurality of electrical power sources of different frequencies.
Viewed from another aspect, the present invention is directed to a method of forming a thin film on a substrate of a semiconductor device wherein the substrate is placed within a reaction chamber and a plasma is created in the chamber by means of a plurality of electrical power sources of different frequencies. A reaction gas is introduced into the reaction chamber and subjected to the plasma to cause the gas to react and deposit a layer on the substrate. The reaction gas is a mixture of tetraethylorthosilicate gas and a halogen gas.
REFERENCES:
patent: 4282267 (1981-08-01), Küyel
patent: 4300989 (1981-11-01), Chang
patent: 4461783 (1984-07-01), Yamazaki
patent: 4668365 (1987-05-01), Foster et al.
patent: 4778721 (1988-10-01), Sliemers
patent: 4818563 (1989-04-01), Ishihara et al.
patent: 4872947 (1989-10-01), Wang et al.
patent: 4894352 (1990-01-01), Lane et al.
patent: 5013691 (1991-05-01), Lory et al.
patent: 5206060 (1993-04-01), Balian et al.
patent: 5215787 (1993-06-01), Homma
patent: 5223457 (1993-06-01), Mintz et al.
patent: 5275977 (1994-01-01), Otsubo et al.
patent: 5279865 (1994-01-01), Chebi et al.
patent: 5288518 (1994-02-01), Homma
patent: 5356722 (1994-10-01), Nguyen et al.
patent: 5429995 (1995-07-01), Nishiyama et al.
patent: 5453305 (1995-09-01),
Applied Materials Inc.
Morris Birgit
Padgett Marianne
LandOfFree
Method of forming a thin film for a semiconductor device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of forming a thin film for a semiconductor device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of forming a thin film for a semiconductor device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3127291