Material or article handling – Load carried along a horizontal linear path – Having gripper means
Reexamination Certificate
1999-09-16
2002-11-19
Olszewski, Robert P. (Department: 3627)
Material or article handling
Load carried along a horizontal linear path
Having gripper means
C414S935000, C414S937000, C294S064200
Reexamination Certificate
active
06481951
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus and method for transferring objects in a processing system. More specifically, the present invention relates to a robot assembly having a multiple sided robot blade which can support one or more substrates.
2. Background of the Related Art
Modern semiconductor processing systems typically process a large number of substrates by moving the substrates between a series of process chambers or enclosures using a robot. To increase the throughput rates of substrates, the trend is to increase the speeds at which substrates are moved in the system. However, increased speeds add complexity to the substrate handling systems. Increased speeds have decreased the allowable tolerances necessary to maintain repeatability because precise movement is needed to avoid damaging the substrate or the films formed thereon as the substrate is moved between the process chambers or enclosures using the robot.
One type of system used in substrate processing is a chemical mechanical polishing (CMP) system used to polish a substrate surface to remove high topography, surface defects, scratches, or embedded particles.
FIG. 1
is a schematic perspective view of one CMP system known as a Mirra® CMP system available from Applied Materials, Inc. of Santa Clara, Calif., which is shown and described in U.S. Pat. No. 5,738,574, incorporated herein by reference. The system
2
includes a loading station
4
and three polishing stations
6
having polishing and/or rinsing pads
8
disposed therein. A rotatable multi-head carousel
10
having four polishing heads
12
is mounted above the stations and indexes the heads from station to station. The loading station
4
is supplied by a front-end substrate transfer region
14
disposed adjacent to the CMP system and is considered a part of the CMP system, although the transfer region
14
may be a separate component. The loading station
4
includes a pedestal
16
on which a substrate is supported following delivery by an overhead track robot
18
prior to and after processing in the polishing stations
6
. Vertically aligned substrate(s)
20
are held in cassette(s)
22
disposed in a fluid in a load tank
24
.
Generally, an overhead track robot
18
includes a downwardly extending blade support arm
28
, also known as a shoulder. A blade
26
is attached to the blade support arm at a pivot joint
30
, typically referred to as a wrist. The track robot
18
is capable of operating the blade support arm in three directions: in a linear direction along an X-axis across the front of the system, in a vertical direction along a Z-axis, and in a rotational direction about the Z-axis. Additionally, the blade
26
is capable of rotating about pivot joint
30
between a substantially horizontal position and a substantially vertical position. The blade
26
typically includes a vacuum port (not shown) for holding a substrate
20
to the blade during transfer within the system
2
.
FIG. 2
is a cross sectional schematic view of the overhead track robot
18
, showing details of the robot components. A blade support arm
28
is vertically disposed below a carriage
32
. The carriage
32
is attached to a drive belt
34
which is supported between two sheaves
36
,
38
. A motor
40
having a worm gear
42
is mounted on the carriage
32
and engages a mating gear
44
mounted on the support arm
28
. The blade support arm
28
supports a support column
60
that is connected to the pivot joint
30
. The pivot joint
30
includes a first portion
46
connected to the blade support arm
28
, a second portion
48
connected to a blade
26
, and a pivot element
50
pivotally connecting the first portion
46
with the second portion
48
of the pivot joint
30
. The pivot joint
30
allows the blade
26
to rotate at a pivot axis
52
between a horizontal and a vertical position. The blade
26
is a single-sided blade, i.e., the blade has one substrate supporting surface that is used to support the substrate during retrieval and delivery of a substrate
20
from and to the various stations. The carriage
32
houses a motor
54
having a worm gear
56
which passes through a worm nut
58
attached to the support column
60
. The blade support arm
28
houses a motor
62
which is attached to a drive shaft
64
and a worm gear
66
. The worm gear
66
engages a mating gear
68
on the pivot joint
30
. The blade
26
is attached by screws (not shown) to the pivot joint
30
.
The blade support arm
28
rotates about the Z-axis
70
when the motor
40
rotates the worm gear
42
which in turn rotates the mating gear
44
connected to the blade support arm. In the typical system, the pivot axis
52
is offset from the Z-axis
70
to enable use of a shorter blade
26
and consequently reduce blade deflection when extended horizontally in the system
2
on delivery and retrieval of a substrate
20
. The worm nut
58
rises and lowers on the worm gear
56
as the motor
54
rotates the worm gear
56
, thus raising and lowering the support column
60
attached thereto. To rotate the pivot joint
30
about the pivot axis
52
, the motor
62
rotates the drive shaft
64
which causes the worm gear
66
to rotate. Rotation of the worm gear
66
causes the mating gear
68
to rotate, thus rotating the second portion
48
of the pivot joint
30
and the blade
26
attached thereto.
Typically, in loading the substrate
20
into the system
2
, the robot
18
rotates the blade
26
into a vertical position, aligns the blade
26
with the substrate, lowers the blade
26
into an adjacent position with the substrate
20
, and vacuum chucks a substrate
20
on a substrate supporting surface of the blade
26
. A vacuum provided to a port on the blade supplies a vacuum to hold the substrate
20
to the supporting surface of the blade
26
so that when the blade is raised vertically, the substrate remains supported by the blade in the vertical position. The robot
18
then rotates the blade
26
about the pivot joint
30
into a substantially horizontal position, moves in the X-direction toward the loading station
4
rotates the blade about the Z-axis
70
, aligns the blade with a loading station
4
, and delivers the substrate to the loading station. The loading station pedestal
16
raises to engage the substrate
20
and lowers the substrate below the blade
26
so that the blade
26
can retract out of the loading station
4
. One of the heads
12
indexes above the pedestal
16
, the pedestal
16
raises the substrate
20
into contact with the head, the head chucks the substrate and indexes to a polishing station
6
for processing. After processing at the station(s), the substrate
20
is returned to the loading station
4
. The robot
18
aligns the robot blade
26
with the loading station
4
to retrieve the processed substrate, retrieves the processed substrate, traverses the X-axis back into an unloading position at the load tank
24
, and returns the substrate
20
to the load tank
24
. The robot then loads another unprocessed substrate and delivers the substrate to the loading station
4
.
One problem with this conventional design and process is that the system may sit idle while awaiting retrieval of an unprocessed substrate following removal of a processed substrate. The time required for the robot to cycle between a processed substrate and an unprocessed substrate is typically referred to as the “swap” time. In the system referenced in
FIG. 1
, the swap time includes the time required to retrieve and place a processed substrate in the load tank and retrieve and deliver an unprocessed substrate to the loading station.
There remains a need for a system and method that can reduce the swap time required to pick up a processed substrate and position an unprocessed substrate for processing in the system.
SUMMARY OF THE INVENTION
The present invention generally provides a processing system having a robot assembly which includes a multiple sided robot blade that can support a substrate on at le
Karazim Michael P.
Shanmugasundram Arul
Applied Materials Inc.
Moser Patterson & Sheridan
O'Connor Gerald J.
Olszewski Robert P.
LandOfFree
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