Adhesive bonding and miscellaneous chemical manufacture – Differential fluid etching apparatus – Having glow discharge electrode gas energizing means
Reexamination Certificate
2001-01-12
2002-08-13
Mills, Gregory (Department: 1763)
Adhesive bonding and miscellaneous chemical manufacture
Differential fluid etching apparatus
Having glow discharge electrode gas energizing means
C156S345490
Reexamination Certificate
active
06432261
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a plasma etching system, and more particularly, relates to a plasma etching system having magnets in an electrode facing a substrate holder so as to control the magnetic field strength in the space in front of the substrate and thereby enabling various types of substrates to be etched and improving the etch rate.
2. Description of the Related Art
First an example of a plasma etching system of the related art will be explained with reference to FIG.
6
. The plasma etching system is provided with a vacuum chamber
100
. At the center of the ceiling
101
of the vacuum chamber
100
a disk-shaped electrode
103
is arranged through a ring-shaped insulator
102
. At the bottom
104
of the vacuum chamber
100
a substrate holder
106
is arranged on a ring-shaped insulator
105
. The electrode
103
and the substrate holder
106
are placed facing each other in a parallel state. Each of the electrode
103
and the substrate holder
106
has a built-in known mechanism for controlling the temperature. Further, the electrode
103
and the substrate holder
106
are connected to power sources
107
and
108
respectively. Electric power for inducing the discharge is supplied between the electrode
103
and the substrate holder
106
by these power sources
107
and
108
. An evacuation port
110
is provided at the surrounding side wall
109
of the vacuum chamber
100
. The evacuation port
110
has connected to it an evacuating mechanism
112
through a pressure control valve
111
. A cylindrical shield member
113
is arranged at the inside of the surrounding side wall
110
around the substrate holder
106
. Plasma is produced in the space inside the shield member
113
. In the space the plasma performs an etching process. The shield member
113
is formed with several holes
113
a.
The inside and the outside of the shield member
113
are connected through these holes. The shield member
113
prevents contamination of the inner surface of the vacuum chamber
100
. The electrode
103
is provided with a gas introduction mechanism for introducing process gas. The gas inlet mechanism is comprised of a gas distribution plate
114
and a gas blowoff plate
115
. The gas introduction mechanism is connected to a gas supply source (not shown) through a gas introduction pipe
116
from the side of the upper surface of the electrode
103
. The gas blowoff plate
115
has a large number of gas blowoff holes
115
a.
The process gas is introduced in the space in front of the substrate holder
106
through these gas blowoff holes. The member
117
provided at the substrate holder
106
is a pushout rod for carrying the substrates
118
.
In the above configuration, a substrate
118
carried by a not shown substrate carrying mechanism is loaded on the substrate holder
106
. Process gas is introduced into the vacuum chamber
100
through the gas introduction pipe
116
. The process gas passes through the gas distribution plate
115
and the gas blowoff plate
114
provided at the bottom side of the electrode
103
and is introduced into the vacuum chamber
100
. On the other hand, the evacuating mechanism
112
evacuates the internal space
100
A of the vacuum chamber
100
to create a required vacuum state. The internal pressure of the shield member
113
is controlled to a suitable pressure by the pressure control valve
111
. The internal pressure of the shield member
113
is determined in accordance with the process. Next, the electric power is fed between the substrate holder
106
and the electrode
103
by the power sources
107
and
108
to cause a discharge in the space (space above substrate in internal space
100
A) in front of the substrate
106
to generate plasma. This plasma is utilized for etching a material to be etched on the substrate
118
. At this time, the process gas introduced into the inside region of the shield member
113
is equally blown off over the substrate
118
by the gas distribution plate
114
and the gas blowoff plate
115
provided in the vacuum at the electrode
103
.
In the configuration of the plasma etching system of the related art, the factors causing changes in the etch rate or etching distribution of the etched material on the surface of the substrate
118
are mainly the internal pressure of the vacuum chamber, the process gas, the fed electric power, and other process conditions. Therefore, conversely, when changing these process conditions, it is possible to change the etch rate or etching distribution of the etched material. Even if the process conditions are changed so as to improve the etch rate or etching distribution by a large extent, in practice, it is difficult to set process conditions to achieve a major improvement. Further, by changing the hardware configuration of a plasma etching system (for example, expanding or reducing the discharge region by modification of the shape of the shield member, or modification of the shape of the substrate holder), it is possible to control the etch rate or etching distribution of the etched material. In this case, however, it is necessary to remodel the system by a large extent in accordance with various processes. This becomes a large problem in terms of costs and the trouble in work.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a plasma etching system which enables the establishment of a better etching process for various etched materials by just the use of magnets and further improvement of the magnets, enables various demands from end users to be met, and enables improvement of the speed of process development.
The plasma etching system according to the present invention is configured as follows to achieve the above object.
The plasma etching system according to the present invention has as a basic configuration a vacuum chamber functioning as a plasma etching chamber and a substrate holder and an electrode arranged facing each other in the inside of the vacuum chamber. A substrate is loaded on the substrate holder. The electrode has a mechanism for introducing a process gas and a gas blowoff plate. The inside of the vacuum chamber is evacuated by an evacuating mechanism and held at a predetermined reduced pressure state or vacuum state. In the state with the substrate loaded on the substrate holder, process gas is introduced inside the vacuum chamber and power is fed between the substrate holder and the electrode to generate plasma. This plasma etches the surface of the substrate. In this configuration, further, a plurality of ring-shaped magnets are arranged at concentric positions at the inside of the vacuum chamber at the rear side of the gas blowoff plate arranged at the electrode. These magnets are arranged so that the poles at the inside surfaces alternate in polarity. The magnetic field strength resulting from the plurality of magnets on the surface of the substrate is made substantially 0 Gauss.
According to the above plasma etching system, the plasma is controlled by providing magnets serving also as a gas distribution plate right behind (or right in front of) the gas blowoff plate so as to create a required distribution of magnetic field and magnetic field strength at the region where the plasma is produced. Due to this, it becomes possible to improve the distribution of the etched material on the substrate and improve the etch rate. By making the magnetic field strength near the surface of the substrate substantially 0, the damage to the substrate is reduced.
In the above configuration, preferably, the magnetic field strength resulting from the plurality of magnets at a plane positioned substantially at the center of the substrate holder and the electrode is made a uniform one of about 100 Gauss. By setting the distribution of the magnetic field resulting from the magnets to the value of the magnetic field strength explained above at the above center position, the above effects are effectively manifested.
In the plasma etching system having the above configuration,
Koguchi Toshiaki
Shimizu Hironari
Takahashi Nobuyuki
Watanabe Kazuhito
Alejandro Luz
Anelva Corporation
Mills Gregory
Oliff & Berridg,e PLC
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