Electric heating – Heating devices – Combined with container – enclosure – or support for material...
Reexamination Certificate
2000-04-10
2001-05-08
Paik, Sang (Department: 3742)
Electric heating
Heating devices
Combined with container, enclosure, or support for material...
C118S724000
Reexamination Certificate
active
06229118
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a wafer handling apparatus of a semiconductor treatment system. More particularly, the present invention relates to a wafer handling apparatus capable of conveying a wafer into a process chamber and/or withdrawing the wafer from the process chamber while the wafer treatment processing is being carried out.
2. Description of the Related Art
In general, a semiconductor treatment system has a process chamber and a handler which conveys a wafer into the process chamber and/or withdraws the wafer from the process chamber. An example of such a handler is disclosed in U.S. Pat. No. 5,746,565 (issued to Tepolt on May 5, 1998). The wafer conveyed into the process chamber is manufactured into a semiconductor device or semiconductor chip through a number of processes including lithography, chemical and physical deposition, and plasma etching processes.
Polymers are commonly generated in the process chamber while the above processes are being carried out. In particular, a significant amount of polymers are intentionally generated in the dry etch process so as to treat the wafer. Furthermore, polymers are inevitably generated in a CVD (chemical vapor deposition) process which forms, at a high temperature, a thin film of polycrystalline material, such as Si, Si
3
N
4
, and SiO
2
, on the wafer disposed in the process chamber.
After the processes have been completed, most of the polymers are discharged out of the process chamber by a vacuum pump. However, some of the remaining polymers float and stick to the side wall of the process chamber having a relatively lower temperature. As a result, with the lapse of time, the amount of polymer on the side wall of the process chamber increases and form aggregates of polymer particles. Such polymer particles can drop onto the wafer being treated, thereby decreasing the quality of the semiconductor device. In addition, the side wall of the process chamber must be manually cleaned periodically in order to remove the polymer particles, resulting in a consumption of time and labor.
In order to overcome the above problem, a method of preventing polymer from sticking to the side wall of the process chamber by heating the side wall or periphery of the process chamber has been suggested. This method is based on the concept that polymers do not stick to high temperature objects. According to the above method, the side wall, lid or electrode installed in the process chamber is heated by a specially manufactured heater to prevent the polymers from sticking to the side wall of the process chamber.
One example of the heating method for the process chamber is disclosed in U.S. Pat. No. 5,516,283. According to the above patented heating method, the outer surface of the process chamber is directly heated by a heater. In addition, heating pads or heating tubes can be installed on the lid of the process chamber or on the side wall of the process chamber.
FIGS. 1 and 2
show a conventional semiconductor treatment system
100
having a process chamber heating apparatus.
As shown in
FIGS. 1 and 2
, a conventional semiconductor treatment system
100
has a loadlock chamber
70
having a handler
10
therein, and a process chamber
80
having an electrode
85
therein.
The handler
10
is operated by a handler driving apparatus
12
, which is controlled by a controller
60
, to thereby convey a wafer
110
stored in a cassette chamber (not shown) onto the electrode
85
of the process chamber
80
. A support
15
for supporting the handler is disposed beneath the handler
10
.
A gate
72
is installed at a partition between the loadlock chamber
70
and the process chamber
80
. The gate
72
is operated by a gate operating apparatus
73
, which is controlled by the controller
60
, to thereby close/open an inlet
75
formed in the partition.
A lid
55
forming the top of the process chamber
80
is provided with a duct (not shown) for supplying a gas into the process chamber
80
. Both the lid
55
and the side wall
82
of the process chamber
80
are connected to a heater
50
. The lid
55
and the side wall
82
of the process chamber
80
are heated by the heater
50
so that polymers
90
floating in the process chamber
80
do not stick to the side wall
82
of the process chamber
80
. The heater
50
is also controlled by the controller
60
.
The conventional semiconductor treatment system
100
having the above-described structure operates as follows.
When the semiconductor manufacturing process begins, the controller
60
issues an operating signal to the handler driving apparatus
12
so that the handler
10
moves into the cassette chamber in which wafers
110
are stored.
Then, the handler
10
grips one wafer
110
using a vacuum and conveys the wafer into the process chamber
80
. At this time, the controller
60
issues an electric signal to the gate operating apparatus
73
so that the gate
72
moves down, thereby opening the inlet
75
formed in the partition between the loadlock chamber
70
and the process chamber
80
.
The handler
10
moves into the process chamber
80
passing through the inlet
75
and returns to its initial position after placing the wafer
110
onto the electrode
85
disposed in the process chamber
80
. At the same time, the controller
60
issues an electric signal to the gate operating apparatus
73
so that the gate
72
moves up, thereby closing the inlet
75
.
After the process has finished, the controller
60
again issues an electric signal which directs the gate operating apparatus
73
to open the inlet
75
. At the same time, the controller
60
issues an electric signal to the handler driving apparatus
12
which causes the handler to move into the process chamber
80
.
Then, the handler
10
grips the wafer
110
using a vacuum and moves into the cassette chamber whereupon the handler
10
places the wafer
110
into a slot of the cassette chamber.
While the above process is being carried out, the controller
60
operates the heater
50
so as that the lid
55
or the side wall
82
of the process chamber
80
is heated, whereby the polymers
90
floating in the process chamber
80
are prevented from sticking to the side wall
82
of the process chamber
80
.
However, although the conventional semiconductor system
100
can prevent the polymers
90
from sticking to the side wall
82
of the process chamber
80
, it cannot prevent the polymers
90
from sticking to the handler
10
.
Typically, the initial temperature of the process chamber, in which a CVD, etching or ion implantation process is carried out, is about 50-120° C. On the other hand, the initial temperature of the handler moving into the precess chamber is about 20-25° C. Thus, polymers floating in the process chamber may stick to the handler
10
when the handler moves into the process chamber.
The polymers which stick to the underside of the handler gradually aggregate as polymer particles, which are then especially likely to fall onto the wafer being treated while the handler moves in the process chamber. Such polymer particles are in fact frequent causes of defects in the semiconductor devices.
For this reason, the handler must be disassembled from the system and cleaned periodically, which action consumes time and labor, and thereby detracts from the efficiency of the semiconductor manufacturing process.
SUMMARY OF THE INVENTION
The present invention has been made to overcome the above-described problems of the prior art. Accordingly, it is an object of the present invention to provide a wafer handling apparatus capable of conveying a wafer into or from a process chamber while preventing polymers from sticking to its handler.
To achieve this object, the wafer handling apparatus comprises a wafer handler, a driving mechanism for moving the wafer handler into and out of a process chamber so that the handler can convey a wafer into or out of the process chamber, and means for controlling the temperature of the handler to one that is substantially identical to the
Cheong Yong Joon
Kim Jae Pil
Jones Volentine, LLC
Paik Sang
Samsung Electronics Co,. Ltd.
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