Refrigeration – Cooled article storage compartment and cooled isolated...
Reexamination Certificate
1999-11-15
2001-10-09
Capossela, Ronald (Department: 3744)
Refrigeration
Cooled article storage compartment and cooled isolated...
C414S939000
Reexamination Certificate
active
06298684
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a substrate transfer robot and, more particularly, to a substrate transfer robot which can efficiently cool its arms, of which temperature normally rises during operation because the arms are arranged in high-temperature vacuum atmosphere.
2. Description of a Related Art
In recent years, semiconductor processing equipment which performs sheet-fed processing not batch processing has been mainly employed because such equipment can satisfy demands of enhancing the accuracy of wafer products and improving the throughput. FIG.
1
(
a
) is a schematic plan view showing an example of the construction of a sheet-fed processing equipment
150
. FIG.
1
(
b
) is a partial sectional side view thereof. The sheet-fed processing equipment
150
comprises a transfer chamber
151
having hexagonal plan view, and a plurality of loading air locks
152
and a plurality of process chambers
153
(only parts thereof are shown) are connected to the transfer chamber
151
via connecting flanges
158
such that the loading air locks
152
and the process chambers
153
are arranged radially about the transfer chamber
151
. These chambers
151
,
153
are sealed with high tightness by shut-off valves
154
provided on the connecting flanges
158
and are vacuumed of a high degree by a vacuum pump, not shown. Treatments for wafers are all performed in a vacuum atmosphere.
Each loading air lock
152
receives a cassette
171
in which wafers processed or to be processed are accommodated. Disposed in the process chambers
153
are respective devices (not shown) for processing the wafers. In the sheet-fed processing equipment
150
, the wafers are transferred among a plurality of the process chambers
153
whereby the wafers are continuously subjected to a plurality of processes.
The construction of the substrate transfer robot
160
will be described in detail with reference to
FIGS. 2
,
3
. A sectional view of
FIG. 2
shows the substrate transfer robot
160
of a three-axial cylindrical coordinate type, with a part being broken away for illustrating the inside construction thereof.
FIG. 3
is a plan view showing arms accommodated inside the transfer chamber
151
. Shown in
FIGS. 2
,
3
is the substrate transfer robot in a state that the end of an end effector
163
as one of the arms extends into the process chamber, not shown, adjacent to the transfer chamber
151
via the connecting flange
158
.
The substrate transfer robot
160
is fixed to an opening
151
a
formed in the bottom of the chamber via a attachment flange
155
such that the arms are positioned within the transfer chamber
151
. The transfer chamber
151
is a polygonal-column-shaped vessel and has a roof plate
156
on the top thereof to keep air tightness. The substrate transfer robot
160
comprises, as shown in
FIG. 3
, a first arm
161
, a second arm
162
which is attached to the end of the first arm
161
and is rotatable independently of the rotation of the first arm
161
, and the end effector
163
which is attached to the end of the second arm
162
. Therefore, the substrate transfer robot
160
can perform the forward and reverse rotation (&thgr;) about the center of a robot shell
165
, the radial movement (R) of each arm end with the rotation of each arm by the rotation of the rotational axis of the arm transferred through a transmission housed in the arm, and the vertical movement of each driving shaft (see FIGS.
1
(
a
),
1
(
b
)).
As shown in
FIG. 2
, predetermined rotation is applied to the arms
161
,
162
, and the end effector
163
of the substrate transfer robot
160
by driving shafts
167
,
168
which are arranged coaxially to each other. The rotation of a drive motor (not shown) arranged within the robot shell
165
is transmitted to the driving shaft
167
,
168
through a reduction gears (not shown) in a lower bearing box
166
. The first driving shaft
167
is a solid steel shaft and is housed in the second driving shaft
168
of a hollow tube type. The second driving shaft
168
of a hollow tube type is arranged coaxially with the central axis of the robot shell
165
to rotate independently of the first driving shaft
167
. The upper end of the first driving shaft
167
extends through an upper bearing portion
169
for the first arm
161
and is fixed to a bearing flange (not shown) of the first arm
161
. Therefore, the rotation of the first driving shaft
167
is directly transmitted to the first arm
161
, thereby rotating the first arm
161
corresponding to the rotational angle of the first driving shaft
167
.
On the other hand, the driving transmitting mechanisms of the second arm
162
and the end effector
163
will now be described, but not shown. Fixed to the upper end of the second driving shaft
168
positioned outside of the bearing flange of the first driving shaft
167
is a timing pulley. A timing belt (not shown) is disposed inside the first arm
161
and is stretched between the timing pulley and the rotational shaft of the second arm
162
. As the first driving shaft
167
is rotated independently of the second driving shaft
168
to rotate the first arm, the rotational shaft of the second arm
162
is rotated through the timing pulley fixed to the second driving shaft
168
and the timing belt inside the first arm. Therefore, the second arm
162
can be rotated in the reverse direction at a ratio of 1:2 to the rotational angle of the first arm
161
i.e. by double the angle of the first arm
161
. Outside of the rotational shaft of the second arm
162
, another timing pulley is fixed to the first arm
161
independently of the rotational shaft of the second arm
162
. The timing pulley drives the end effector
163
at the end of the second arm
162
through a belt. The rotation of the timing pulley is transmitted to a rotational shaft at the other end of the second arm
162
through the timing belt within the second arm
162
so as to rotate the rotational shaft. The rotation of the rotational shaft moves the end effector
163
fixed to the rotational shaft along a straight line in the transferring direction. The arms structured as stated above are operated according to sequential control. A sequence of operation for the linear transference of the wafers between the loading air lock and the process chamber can be performed.
By the sequential control with the original position where the second arm is superposed on the first arm, the arms and the end effector perform the respective rotation and the telescopic movement whereby the wafers (not shown) can be transferred between the predetermined chambers by the adsorption at the end of the end effector. During this, the valve
154
(see FIG.
1
(
b
)) is opened or closed when the end effector passes the connecting flange
158
. Though, for example, a chemical vapor deposition (CVD) process among the substrate processes is performed in relatively low-temperature atmosphere (350-600° C.), a diffusion process may be performed in high-temperature atmosphere about 1200° C. During this process, the end of the second arm and the end effector extending in the process chamber are subjected to radiant heat from the heat source so that heat is stored in the end effector and the arms, increasing their temperature.
Conventionally, to prevent the increase in the temperature of the arms, insulating reflectors for heat reflection are attached on outside walls of the arms. This prevents the arms from being subjected directly to radiant heat, thus preventing the temperature increase in the arms. When the temperature for the process is 1000° C. or more, however, the reflectors as the cooling mechanism become high temperature, not preventing the increase in the temperature of the arms.
The driving shafts for the arms are supported by bearing means such as ball bearings. That is, the driving shafts are connected to the retainer side by point or line contacts with movable bodies such as a plurality of steel balls, rollers, or the like in the bearings. Unlike the n
Capossela Ronald
Jel Corporation
Kanesaka & Takeuchi
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