Coating apparatus – Gas or vapor deposition – With treating means
Reexamination Certificate
2001-10-22
2004-05-04
Hassanzadeh, Parviz (Department: 1763)
Coating apparatus
Gas or vapor deposition
With treating means
C118S724000, C156S345410, C156S345370
Reexamination Certificate
active
06729261
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a plasma processing apparatus used for processing semiconductor wafers and the like by the action of a plasma generated by microwave.
2. Description of the Background Art
In recent years, semiconductor products have been increased in density and reduced in size to a great degree. Accordingly, some manufacturing processes of the semiconductor products employ a plasma processing apparatus for such processing as film deposition, etching and ashing. In particular, there is a tendency to use a microwave plasma apparatus since the microwave plasma apparatus can produce a plasma in a stable manner even in a high-vacuum state of a relatively low pressure, specifically from about 0.1 to several tens of mTorr, by using the microwave or a combination of the microwave and a magnetic field from a ring-shaped coil to produce a high-density plasma.
Such a microwave plasma processing apparatus is disclosed for example in Japanese Patent Laying-Open Nos. 3-191073 and 5-343334 and Japanese Patent Laying-Open No. 9-181052 filed by the applicant of the present application. A general plasma processing apparatus using the microwave is described briefly below in conjunction with
FIGS. 9 and 10
.
FIG. 9
shows a structure of a conventional and generally employed plasma processing apparatus and
FIG. 10
is a plan view of a planar antenna member.
Referring to
FIG. 9
, a plasma processing apparatus
2
includes a process chamber
4
which can be evacuated, a mount base
6
on which a semiconductor wafer W is mounted, and an insulating plate
8
provided in an airtight manner on a ceiling opposite to mount base
6
. Insulating plate
8
transmitting microwave is formed of aluminum nitride or the like in the shape of a disk, for example.
Plasma processing apparatus
2
further includes, on the upper side of insulating plate
8
, a planar antenna member
10
in the shape of a disk with a thickness of several millimeters as shown in
FIG. 10 and a
wave-delay member
12
formed of a dielectric for example for decreasing the wavelength of microwave in the radial direction of planar antenna member
10
as required. In addition, plasma processing apparatus
2
includes a ceiling cooling jacket
16
above wave-delay member
12
that has a cooling channel
14
formed for flowing a cooling water therein in order to cool wave-delay member
12
and the like. Antenna member
10
includes a great number of microwave radiation holes
18
that are through holes nearly circular in shape. In general, microwave radiation holes
18
are arranged concentrically as shown in
FIG. 10
or spirally. An internal cable
22
of a coaxial waveguide
20
is connected to the central part of planar antenna member
10
for guiding a microwave of 2.45 GHz for example produced by a microwave generator (not shown). The microwave is transmitted radially in the radial direction of antenna member
10
and also discharged from microwave radiation holes
18
provided in antenna member
10
to be transmitted downward through insulating plate
8
into process chamber
4
. The microwave causes a plasma in process chamber
4
for performing a predetermined plasma process such as etching and film deposition for a semiconductor wafer.
Insulating plate
8
demarcating the ceiling of process chamber
4
is made of aluminum nitride (AlN) having in general a relatively low dielectric loss. However, heat is still generated due to the dielectric loss so that much of the microwave power is wastefully consumed as the dielectric loss, and consequently, the energy efficiency deteriorates. Moreover, even if insulating plate
8
is made of any material of lower dielectric loss, heat generation inevitably occurs due to the dielectric loss. Those materials constituting insulating plate
8
have a relatively low thermal conductivity and thus the generated heat remains in insulating plate
8
without being dissipated sufficiently to the sidewall of process chamber
4
. Accordingly, the temperature of the heat remaining in insulating plate
8
excessively rises, which results in a problem that the temperature distribution of semiconductor wafer W placed adjacent to insulating plate
8
is adversely affected.
SUMMARY OF THE INVENTION
One object of the present invention is to provide a plasma processing apparatus capable of efficiently cooling an insulating plate having a relatively low thermal conductivity.
A plasma processing apparatus according to one aspect of the present invention includes a process chamber including an opened ceiling and an internal space which can be evacuated, an insulating plate divided into a plurality of regions and airtightly attached to the ceiling of the process chamber, a mount base placed in the process chamber for mounting thereon a workpiece to be processed, a planar antenna member placed above the insulating plate and including a microwave radiation hole for transmitting therethrough microwave used for generating plasma, the microwave transmitted through the insulating plate into the process chamber, gas supply means for supplying a predetermined gas into the process chamber, and a heat medium path for flowing a heat medium along a line by which the insulating plate is divided into a plurality of regions.
With the structure as detailed above, the heat medium flowing through the heat medium path can be used to control the temperature of the insulating plate. Prevention is thus possible of a thermally adverse influence on a workpiece to be processed.
The plasma processing apparatus may further include a ring-shaped heat medium path for flowing the heat medium along a peripheral part of the insulating plate so as to facilitate the temperature control of the insulating plate.
Preferably, the plasma processing apparatus further includes heat medium temperature control means for controlling the temperature of the heat medium. The heat medium temperature control means controls the temperature of the heat medium to render the temperature of the insulating plate substantially constant in a normal process. The heat medium temperature control means controls the temperature of the heat medium to heat the insulating plate to at least a predetermined temperature in cleaning.
The insulating plate is formed of any ceramic material such as aluminum nitride and alumina, or quartz, for example. The insulating plate is divided substantially radially from a central part of the insulating plate.
Preferably, the heat medium path and the microwave radiation holes of the planar antenna member are displaced from each other with respect to the direction in which the microwave is transmitted. Then, it never occurs that the microwave from the microwave radiation holes is radiated onto and absorbed by the heat medium path. The microwave can thus be supplied efficiently into the process chamber.
When the plasma processing apparatus includes the ring-shaped heat medium path in addition to the heat medium path, the ring-shaped heat medium path and the microwave radiation holes of the planar antenna member may be displaced from each other with respect to the direction in which the microwave is transmitted.
According to one embodiment of the present invention, the plasma processing apparatus further includes a support frame member supporting the insulating plate divided into a plurality of regions, and the support frame member includes the heat medium path. The support frame member may include the heat medium path and the ring-shaped heat medium path. Preferably, in order to efficiently supply the microwave into the process chamber, the support frame member and the microwave radiation holes of the planar antenna member are displaced from each other with respect to the direction in which the microwave is transmitted.
Preferably, the plasma processing apparatus further includes first sealing means for airtightly sealing between the insulating plate and the support frame member and second sealing means for airtightly sealing between the support frame member and the process chambe
Finnegan Henderson Farabow Garrett & Dunner LLP
Tokyo Electron Limited
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