Adhesive bonding and miscellaneous chemical manufacture – Differential fluid etching apparatus – With microwave gas energizing means
Reexamination Certificate
2001-04-26
2003-03-04
Mills, Gregory (Department: 1763)
Adhesive bonding and miscellaneous chemical manufacture
Differential fluid etching apparatus
With microwave gas energizing means
C156S345420, C118S7230MW, C118S7230AN
Reexamination Certificate
active
06527909
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to a plasma processing apparatus utilizing a microwave.
2. Description of the Related Art
Conventionally, there is known a plasma processing apparatus which includes a plane antenna, as shown in FIG.
3
.
This plasma processing apparatus
71
has a processing container
73
in the form of a bottomed pipe as a whole and a quartz plate
75
arranged on a ceiling part of the container
73
in an airtight manner, forming a closed processing space S inside the container
73
. Accommodated in the processing container
73
is a mount table
77
which mounts a semiconductor wafer W thereon. The mount table
77
is connected with a bias high-frequency power source
79
through power lines. Through the sidewall of the container
73
, a gas nozzle
81
is arranged to introduce process gas into the container
73
and further connected with a process gas source
83
. Further, the container
73
is provided, in a bottom thereof, with exhaust ports
85
communicated with a not-shown vacuum pump.
While, a plane antenna member
87
is arranged on the quartz plate
75
closing up the top part of the processing container
73
. The plane antenna member
87
is formed by a bottom plate of a radial waveguide box
89
and also attached to the top of the quartz plate
75
. The radial waveguide box
89
is provided as a short, disc, hollow and cylindrical container. Connected with the top center of the disc radial waveguide box
89
is an outer tube
93
A of a coaxial waveguide
93
which has the other end connected with a microwave generator
91
. In the coaxial waveguide
93
, an inner cable
93
B is connected to the center of the disc-shaped antenna member
87
.
The antenna member
87
is made from a copper plate and has a number of slots
95
formed therein. In order to shorten a wavelength of microwave thereby realizing a short guide-wavelength, the radial waveguide
89
fills its interior with a dielectric
97
of a predetermined dielectric constant.
In the constitution mentioned above, the microwave produced in the microwave generator
91
is propagated in the coaxial waveguide
93
and expands in the radial waveguide box
89
in the radial direction. Then, the microwave is emitted through the slots
95
of the antenna member
87
downwardly thereby to produce a plasma in the processing container
73
.
In the above processing apparatus
71
, however, an uneven electric field is formed below the plane antenna member
87
, causing an unevenness in the processing for the wafer W. That is, the electric field emitted through the slots
95
of the antenna member
87
is reflected on the inside wall of the processing container
73
to intensify the electric field at the center of the container
73
, as shown in a lower part of FIG.
3
. Therefore, a problem arises in that an unevenness is produced in processing the wafers, particularly, large-diameter wafers.
SUMMARY OF THE INVENTION
In order to solve the above-mentioned problem, the object of the present invention is to provide a plasma processing apparatus which is capable of realizing a generally uniform electric field below the antenna member to accomplish an uniform wafer processing.
The first feature of the present invention resides in the provision of a plasma processing apparatus comprising: a processing container shaped to be a hollow cylinder with a bottom and also provided, inside thereof, with a mount table for mounting an object to be processed thereon; a lid body for covering an upper opening of the processing container in an airtight manner, the lid body having a dielectric; a microwave supplier for supplying a microwave; a waveguide having one end thereof connected to the microwave supplier, the waveguide extending from the microwave supplier toward the lid body and also having an waveguide space formed therein; a radial waveguide box connected to the other end of the waveguide, the radial waveguide box having a flange part expanding from the outer end of the waveguide outward in the radial direction and a sidewall extending from the flange part toward the lid body downward thereby to define a waveguide space therein; an antenna member for covering a lower opening of the radial waveguide box and having a plurality of slots formed therein, the antenna member being arranged in parallel with the lid body; and a metallic reflector formed at the center of the antenna member on the side of the mount table so as to extend toward the mount table, for reflecting a high-frequency electric field reflected by an inner wall of the processing container.
According to the second feature of the invention, the reflector is arranged to project from the lid body into the processing container.
According to the third feature of the invention, the reflector is arranged not to project from the lid body into the processing container.
According to the fourth feature of the invention, a tip of the reflector is embedded in the lid body.
According to the fifth feature of the invention, the reflector is shaped in a hollow cylinder or a pillar.
According to the sixth feature of the invention, the reflector is shaped in a hollow cylinder with circular sectional shape or a pillar with circular sectional shape.
According to the seventh feature of the invention, the reflector is shaped in a hollow cylinder with polygonal sectional shape or a pillar with polygonal sectional shape.
According to the eighth feature of the invention, in the plasma processing apparatus, an absorbing member is arranged close to the outer circumference of the radial waveguide box to absorb the high-frequency electric field.
According to the ninth feature of the invention, in the plasma processing apparatus, an absorbing member is arranged in the outer circumference of a space between a lower face of the antenna member and a lower face of the lid body having the dielectric.
According to the tenth feature of the invention, the waveguide includes an inner conductor and an outer conductor in coaxial with the inner conductor so that the microwave is propagated between the inner conductor and the outer conductor, an end of the outer conductor on the side of the lid body being connected with the radial waveguide, while an end of the inner conductor on the side of the lid body being connected with a central part of the antenna member.
According to the eleventh feature of the invention, the waveguide has circular sectional shape, microwave in TM mode being propagated therethrough.
The twelfth feature of the invention resides in the provision of another plasma processing apparatus comprising: a processing container shaped to be a hollow cylinder with a bottom and also provided, inside thereof, with a mount table for mounting an object to be processed thereon; a lid body for covering an upper opening of the processing container in an airtight manner, the lid body having a dielectric; a microwave supplier for supplying a microwave; a waveguide having one end thereof connected to the microwave supplier, the waveguide extending from the microwave supplier toward the lid body and also having an waveguide space formed therein; a radial waveguide box connected to the other end of the waveguide, the radial waveguide box having a flange part expanding from the other end of the waveguide outward in the radial direction and a sidewall extending from the flange part toward the lid body downward thereby to define an waveguide space therein; an antenna member for covering a lower opening of the radial waveguide box and having a plurality of slots formed therein, the antenna member being arranged in parallel with the lid body; and an absorber arranged at the central part of the antenna member on the side of the mount table so as to project toward the mount table, for absorbing the high-frequency electric field.
According to the thirteenth feature of the invention, in the above plasma processing apparatus, the absorber is arranged to project from the lid body into the processing container.
According to the fourteenth feature o
Ishii Nobuo
Yasaka Yasuyoshi
Finnegan Henderson Farabow Garrett & Dunner LLP
Hassanzadeh P.
Mills Gregory
Tokyo Electron Limited
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