Coating apparatus – Gas or vapor deposition – Work support
Reexamination Certificate
2000-04-27
2002-03-19
Mills, Gregory (Department: 1763)
Coating apparatus
Gas or vapor deposition
Work support
C118S7230MW, C118S713000, C156S345420
Reexamination Certificate
active
06358324
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a microwave plasma processing apparatus and, more particularly, to a microwave plasma processing apparatus having a vacuum chamber in which an object to be processed such as a semiconductor wafer is subjected to plasma processing.
2. Description of the Related Art
Recently, in a semiconductor device manufacturing process, plasma processing apparatuses have been used to perform semiconductor producing processes such as a deposition process, an etching process or an ashing or stripping process since high-density integration and fine structure are required for semiconductor devices. Particularly, a microwave plasma processing apparatus has become popular since the microwave plasma processing apparatus is capable of generating stable plasma at a relatively low vacuum of 0.1 millitorr (mTorr) to several tens of mTorr. The microwave plasma processing apparatus generates high-density plasma by using a microwave or a combination of a microwave and a magnetic field generated by a ring-like coil.
In a typical microwave plasma processing apparatus, a 2.45 GHz microwave is introduced into a process chamber via a waveguide and a slot electrode. A reaction gas is also introduced into the process chamber, which is maintained at a predetermined negative pressure. The reaction gas introduced into the process chamber is changed into active radicals and ions by the microwave so as to produce plasma. An object to be processed such as a semiconductor wafer is placed in the process chamber so that a predetermined process such as an etching process is performed on the object by utilizing the action of the plasma.
FIG. 1
is an illustration of a structure of a conventional plasma processing apparatus. The conventional plasma processing apparatus
1
shown in
FIG. 1
comprises: a process chamber
2
in which an object W to be processed is placed; a microwave generator
4
which generates a microwave to be introduced into the process chamber
2
; and vacuum pumps
6
connected to the process chamber
2
for maintaining the process chamber
2
at a predetermined negative pressure.
The object W to be processed is placed on a susceptor
8
provided in the process chamber
2
. The susceptor
8
is supported by a rod
10
which is moved up and down by a vertical moving mechanism
12
. The rod
10
extends out of the process chamber
2
with a bellows
14
provided on the bottom of the process chamber
2
so as to hermetically seal the process chamber
12
.
It should be noted that
FIG. 1
is a schematic illustration for mainly explaining the vertical movement of the susceptor
8
and the positions of the vacuum pumps
6
, and other members such as a gate connected to other cluster chambers or a reaction gas supply port are omitted for the sake of simplification of the figure.
The susceptor
8
provided in the process chamber
2
shown in
FIG. 1
can be moved up and down by the vertical moving mechanism
12
via the rod
10
so that a processing speed of the object W to be processed can be adjusted by changing a process condition of the object W since the processing speed varies depending on a vertical position of the object W within the process chamber
2
. For example, when the plasma processing is managed in accordance with a time period during which the object W is subjected to the plasma processing, the vertical position of the object W to be processed must be adjusted so as to obtain a desired degree of plasma processing within a predetermined time period.
The process chamber
2
has the bellows
14
on the bottom thereof, and the rod
10
extends to the vertical moving mechanism through the bellows
14
so as to maintain a hermetic seal between the rod
10
and the process chamber
2
. If the rod
10
horizontally extends within the process chamber
2
and the vertical moving mechanism
12
is provided on the side of the process chamber
2
, the hermetic seal of the process chamber
2
cannot be achieved by the bellows
14
since the direction of movement of the rod
10
is perpendicular to the direction of deformation of the bellows
14
. Accordingly, in order to move the susceptor
8
up and down and achieve a hermetic seal between the rod
10
and the process chamber
2
, it is preferable that the bellows
14
be positioned on the bottom of the process chamber
2
as shown in FIG.
1
. In this case, the length of the rod
10
can be short since the vertical moving mechanism
12
is positioned directly underneath the susceptor
8
, and a smooth movement of the rod
10
can be achieved.
The vacuum pumps
6
are directly connected to the bottom of the process chamber
2
. That is, each of the vacuum pumps
6
is mounted on the process chamber without any connecting pipe therebetween. The structure shown in
FIG. 1
can achieve a better vacuum characteristic, as long as maintenance of a high-vacuum condition is concerned, than a structure of the plasma processing apparatus in which a vacuum pump is connected to a process chamber via a connecting pipe.
Two or more vacuum pumps
6
are provided symmetrically around the bottom of the process chamber
2
so as to uniformly evacuate air or gas from the process chamber
2
so that a uniform plasma density can be achieved in the process chamber
2
. This is because, if the plasma in the process chamber
2
is locally concentrated, the degree of the plasma processing on the object W will vary according to the said local concentration.
However, the plasma processing apparatus
1
shown in
FIG. 1
must be large in its size and complex in its structure since the plurality of vacuum pumps
6
are provided diagonally around the periphery of the bottom of the process chamber
2
. Accordingly, a manufacturing cost of the plasma processing apparatus
1
is high.
Additionally, the structure of the plasma processing apparatus
1
in which the plurality of vacuum pumps
6
are provided still has a problem in that the plasma density cannot be completely uniform in the process chamber
2
since the number of vacuum pumps
6
which can be connected to the periphery of the bottom of the process chamber
2
is limited. The inventors found that a uniform plasma density can be achieved by a single vacuum pump being provided in the center of the bottom of the process chamber
2
. However, in the structure shown in
FIG. 1
, the vacuum pump
6
cannot be moved to the center of the bottom of the process chamber
2
since the rod
10
and the vertical moving mechanism
12
are positioned in the center of the bottom of the process chamber
2
.
SUMMARY OF THE INVENTION
It is a general object of the present invention to provide an improved and useful microwave plasma processing apparatus in which the above-mentioned problems are eliminated.
A more specific object of the present invention is to provide a microwave plasma processing apparatus having a process chamber in which a susceptor is movable by a vertical moving mechanism having a simple structure while a vacuum pump is positioned in the center of the bottom of the process chamber.
In order to achieve the above-mentioned objects, there is provided according to one aspect of the present invention a microwave plasma processing apparatus, comprising: a process chamber in which an object to be processed is subjected to plasma processing under a predetermined negative pressure environment; a susceptor provided in the process chamber, the susceptor being configured to hold the object thereon; a susceptor moving member connected to the susceptor; a first bellows provided to a bottom of the process chamber, the first bellows being connected to the susceptor moving member so as to allow a vertical movement of the susceptor moving member while providing a hermetic seal to the process chamber to maintain the predetermined negative pressure environment in the process chamber; a susceptor moving mechanism provided outside the process chamber, the susceptor moving mechanism moving the susceptor moving member in the vertical direction so as to move the su
Hongoh Toshiaki
Kawakami Satoru
Oosawa Tetsu
Yuasa Mitsuhiro
Hassanzadeh P.
Mills Gregory
Pillsbury & Winthrop LLP
Tokyo Electron Limited
LandOfFree
Microwave plasma processing apparatus having a vacuum pump... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Microwave plasma processing apparatus having a vacuum pump..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Microwave plasma processing apparatus having a vacuum pump... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2840155