Semiconductor device manufacturing: process – Chemical etching – Vapor phase etching
Reexamination Certificate
1998-09-14
2001-12-25
Hiteshew, Felisa (Department: 1765)
Semiconductor device manufacturing: process
Chemical etching
Vapor phase etching
C438S710000, C438S726000, C438S728000
Reexamination Certificate
active
06333269
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a plasma treatment system and method for depositing a thin film, such as SiOF and SiO
2
films, on a substrate to be treated, such as a semiconductor wafer, by a plasma treatment, such as an ECR (Electron Cyclotron Resonance) treatment.
2. Related Background Art
An aluminum wiring is typically used as a wiring pattern for an integrated circuit. An SiO
2
film, an SiOF film or the like is typically used as an interlayer insulator film for insulating the aluminum wiring. These films are formed by means of, e.g., a plasma treatment system for carrying out the ECR plasma treatment as shown in FIG.
11
.
For example, in this system, a microwave of, e.g., 2.45 GHZ, is supplied to a plasma producing chamber
1
A by means of a waveguide
11
, and a magnetic field of, e.g., 875 gausses, is applied thereto, so that the interaction (the Electron Cyclotron Resonance) between the microwave and the magnetic field activates a plasma gas, such as Ar or O
2
gas, and a thin film deposition gas, such as SiH
4
gas, which is introduced into a thin film deposition chamber
1
B, to produce plasma serving as active species to deposit a thin film on a semiconductor wafer (which will be hereinafter referred to as a “wafer”) W mounted on a mounting table
12
.
The magnetic field is applied as a downward magnetic field, which extends from the plasma chamber
1
B to the thin film deposition chamber
1
B, by the combination of a main electromagnetic coil
13
, which is provided so as to surround the plasma chamber
1
A, and an auxiliary electromagnetic coil
14
, which is provided below the thin film deposition chamber
1
B.
By the way, the above described plasma treatment system is designed to adjust the shape of the magnetic field by changing the currents flowing through the main electromagnetic coil
13
and the auxiliary electromagnetic coil
14
since the main electromagnetic coil
13
and the auxiliary electromagnetic coil
14
are fixed to the aforementioned positions. However, in a case where only such adjustment of coil current is carried out, when only the current of one of the electromagnetic coils is adjusted, the shape of the magnetic field itself is not changed although the intensity of the magnetic force on the magnetic potential surface of the magnetic field applied by the adjusted electromagnetic coil is changed.
For example, a divergent field shown in
FIG. 12
can be obtained by causing the current flowing through the auxiliary electromagnetic coil
14
to be far smaller than the current flowing through the main electromagnetic coil
13
or to be zero. However, if only the current flowing through the main electromagnetic coil
13
is increased without changing the current flowing through the auxiliary electromagnetic coil
14
, only the intensity of the magnetic force on the magnetic potential surface shown by the dotted lines in
FIG. 12
is increased.
In addition, when the respective currents of the main electromagnetic coil
13
and the auxiliary electromagnetic coil
14
are adjusted, the shape of the magnetic field is greatly changed. For example, when the current flowing through the auxiliary electromagnetic coil
14
is higher than that in the case of the divergent field, a mirror field shown in FIG.
13
(
a
) is formed, and when the direction of the current flowing through the auxiliary electromagnetic coil
14
is inverted, a cusp field shown in FIG.
13
(
b
) is formed. As described above, the shape of the applied magnetic field changed by only the adjustment of currents flowing through the electromagnetic coils is restricted, and the degree of freedom for the shape of the obtained magnetic field is small.
By the way, in recent years, a thin film of a two-layer structure obtained by stacking an SiOF film and an SiO
2
film is provided in order to obtain a high quality interlayer insulator film. Such a film is continuously formed in, e.g., the above described plasma treatment system. However, the conditions in the processes for depositing these films are different from each other. If the shape of the magnetic field is optimized for one of the films, the inplane uniformity of thickness of the other film is deteriorated.
Therefore, it is required to adjust the shape of the magnetic field so as to enhance the inplane uniformity of thickness of both films. However, as described above, the degree of freedom for the shape of the magnetic field is small in the present circumstances, so that it is very difficult to adjust the shape of the magnetic field. In recent years, the scale down of devices is accelerated, so that it is required to provide thinner interlayer insulator films. Therefore, it is conceived that it is more difficult to adjust the shape of the magnetic field.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to eliminate the aforementioned problems and to provide a plasma treatment system which can enhance the degree of freedom for the shape of an obtained magnetic field by providing a movable magnetic field forming means.
It is another object of the present invention to provide a plasma treatment method which can enhance the inplane uniformity of thickness of first and second films when the first and second films are continuously deposited on a substrate to be treated.
In order to accomplish the aforementioned and other objects, according to one aspect of the present invention, there is provided a plasma treatment system for producing plasma in a vacuum vessel by the electron cyclotron resonance between a microwave and a magnetic field to treat a substrate to be treated, with the produced plasma, wherein magnetic field forming means for forming a magnetic field in the vacuum vessel is provided so as to be movable in a direction perpendicular to the substrate, and the shape of the magnetic field formed in the vacuum vessel is adjusted by moving the magnetic field forming means in the direction.
The magnetic field forming means may comprise first magnetic field forming means provided around a central axis of the substrate so as to surround a region facing a surface to be treated of the substrate, and second magnetic field forming means provided around the central axis so as to surround a region below at least the substrate, at least one of the first and second magnetic field forming means being provided so as to be movable in a direction perpendicular to the substrate. In this case, the magnetic field forming means may be an electromagnetic coil.
According to another aspect of the present invention, there is provided a plasma treatment method for activating a thin film deposition gas to produce plasma in a vacuum vessel by the electron cyclotron resonance between a microwave and a magnetic field to sequentially deposit first and second films on a substrate to be treated, the plasma treatment method comprising the steps of: arranging magnetic forming means for forming a magnetic field in the vacuum vessel, at a first position to activate a first thin film deposition gas to produce plasma to form a first film on a surface to be treated of the substrate; and arranging the magnetic field forming means at a second position to activate a second thin film deposition gas to produce plasma to form a second film on the surface of the first film formed on the substrate.
According to another aspect of the present invention, there is provided a plasma treatment method for supplying a microwave into a vacuum vessel by high-frequency producing means and for forming a magnetic field into the vacuum vessel by magnetic field forming means, to produce plasma in the vacuum vessel by the electron cyclotron resonance between the microwave and the magnetic field to treat a substrate to be treated, with the produced plasma, the plasma treatment method comprising: a first step of introducing the substrate into the vacuum vessel and producing plasma to heat the substrate; and a second step of activating a thin film deposition gas to produce plasma in the vacuum vessel to fo
Amano Hideaki
Naito Yoko
Hiteshew Felisa
Smith , Gambrell & Russell, LLP
Tokyo Electron Limited
Tran Binh X.
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