Adhesive bonding and miscellaneous chemical manufacture – Differential fluid etching apparatus – Having glow discharge electrode gas energizing means
Reexamination Certificate
1998-07-28
2004-12-28
Hassanzadeh, Parviz (Department: 1763)
Adhesive bonding and miscellaneous chemical manufacture
Differential fluid etching apparatus
Having glow discharge electrode gas energizing means
C118S7230ER
Reexamination Certificate
active
06835279
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention concerns a modified magnetron high-frequency discharge type plasma generation apparatus.
2. Description of the Related Art
In general, in order to fabricate a solid device, it is necessary to employ a surface treatment apparatus for subjecting the surface of the substrate of the solid device to some prescribed treatment. By solid device here is meant, for example, any semiconductor device or liquid crystal display device, etc. And by the substrate of the solid device is meant a substrate such as a wafer for a semiconductor device or glass plate for a liquid crystal display device.
Such surface treatment apparatuses include dry etching apparatuses and CVD (chemical vapor deposition) devices, and so on. By dry etching apparatus here is meant an apparatus for dry-etching the surface of a substrate. And by CVD apparatus is meant an apparatus for using a chemical reaction to form a prescribed thin film on the surface of a substrate.
Among these surface treatment apparatuses are plasma surface treatment apparatuses which use plasma to effect prescribed treatments on substrate surfaces. In order to implement such a plasma surface treatment apparatus, it is necessary to have a plasma generation apparatus for generating plasma.
In recent years, a demand has risen for plasma generation apparatuses which can generate plasma under conditions of low discharge gas pressure, reflecting the trend toward greater solid device miniaturization.
More specifically, when a solid device is further miniaturized, greater precision in the direction of ion incidence on the substrate is demanded. This incidence direction precision depends on the pressure of the discharge gas. That is, when the gas pressure is low, the incidence direction precision is higher, and when that pressure is high, the precision is lower. This is because, when the gas pressure is high, as the ions in the plasma impact the substrate while being accelerated by the sheath voltage on the surface of the substrate, they collide with neutral gas before reaching the surface. Thus it is necessary to generate plasma at low gas pressures to cope with further miniaturization in solid devices.
By low gas pressure, furthermore, although this will differ according to the type of surface treatment involved, is generally meant a pressure of 30 m Torr or less. By way of comparison, when a semiconductor device wafer is subjected to dry etching, the plasma should be generated with a gas pressure of about 10 m Torr.
The magnetron high-frequency discharge type of plasma generation apparatus has been known for some time as a plasma generation apparatus capable of generating plasma at low gas pressures. This apparatus generates plasma by magnetron discharges using a high-frequency electric field.
An example of such a plasma generation apparatus is described in the literature cited below.
Reference: Unexamined Patent Application [Tokkai] No. H7-201831 [1995].
The plasma generation apparatus described in the cited literature is fashioned so that it generates plasma by generating magnetron discharges by a high-frequency electric field formed by a cylindrical discharge electrode and a magnetic field formed by ring-shaped permanent magnets.
With the plasma generation apparatus described in the cited patent application, however, there is a problem in that high-density plasma cannot be generated in the center of the plasma generation region. This is due to fact that, in this plasma generation apparatus, plasma is mainly generated at the surface of the discharge electrode. By center of the plasma generation region here is meant the center in the radial dimension of the discharge electrode (and so hereinafter).
Thus, with this plasma generation apparatus, when a plasma surface-treatment apparatus is implemented, there is a problem in that surface treatment cannot be performed under uniform plasma density conditions.
In order to resolve this problem, it is only necessary to install the susceptor in a location that is considerably removed from the discharge electrode in the axial direction thereof. By susceptor here is meant a substrate carrier on which the substrates being processed are carried.
With such a configuration as this, however, although it is possible to perform surface treatment under uniform plasma density conditions, it is not possible to perform surface treatment under conditions of high plasma density, which constitutes a new problem. This is due to the fact that, in a plasma generation apparatus such as that described above, as the distance from the discharge electrode increases in the axial direction, plasma density declines due to plasma diffusion loss. As a consequence, with such a configuration as this, de surface treatment processing speed becomes slow.
In view of the foregoing, there is a need for a modified magnetron high-frequency type of plasma generation apparatus that can generate high-density plasma in the center of the discharge electrode as well as at the periphery. By periphery of the plasma generation apparatus here is meant the peripheral region in the radical dimension of the discharge electrode (and so hereinafter).
SUMMARY OF THE INVENTION
Thereupon, an object of the present invention is to provide a modified magnetron high-frequency discharge type plasma generation apparatus capable of generating high-density plasma in the center of the plasma generation region as well as at the periphery.
The plasma generation apparatus for the purpose of resolving the problem noted above, comprises a vacuum vessel, gas induction means, exhaust means, discharge electrode, first high-frequency electric power application means, magnetic force line formation means, and two walls.
The vacuum vessel is a vessel in the interior of which is established a plasma generation region. The gas induction means are means for inducting discharge gas into the interior of the vacuum vessel. The exhaust means are means for exhausting the atmosphere in the interior of the vacuum vessel. The discharge electrode is an electrode positioned so as to enclose the plasma generation region. This electrode is formed in a cylindrical shape.
The first high-frequency electric power application means are means for applying high-frequency electric power to the discharge electrode. The magnetic force line generation means are means for forming prescribed lines of magnetic force. These magnetic force lines have portions that roughly parallel the discharge electrode center axis, the length of these parallel portions becoming longer the closer they are to the center axis. The two walls are walls that define the scope of the plasma generation region in the dimension of the discharge electrode center axis. These two walls are positioned so as to sandwich the plasma generation region between them in the dimension of the center axis of the discharge electrode.
The plasma generation apparatus moreover, is characteristic in that it is configured so that the magnetic force lines that pass through the center of the plasma generation region are shaped so that they do not intersect the two walls.
These magnetic force lines are formed, for example, by suitably setting the size of the vacuum vessel, the position and configuration of the magnetic force lines forming means, and the position of and interval between the two walls, etc.
With the plasma generation apparatus when plasma is generated, discharge gas is inducted by the gas induction means into the interior of the vacuum vessel. When is done, furthermore, the atmosphere in the interior of the vacuum vessel is exhausted by the exhaust means. Thus the interior of the vacuum vessel is established in a condition of reduced pressure. In this case, moreover, high-frequency electric power is applied to the discharge electrode. Thus is formed a high-frequency electric field component oriented in the radical direction of the discharge electrode. And, furthermore, magnetic force lines having portions roughly parallel to the center axis of the discharge elec
Iizuka Satoru
Li Yunlong
Sato Noriyoshi
Hassanzadeh Parviz
Hitachi Kokusai Electric Inc.
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