Robot for handling

Details Robot for handling Robot for handling

1999-08-19

2001-02-20

Herrmann, Allan D. (Department: 3682)

Machine element or mechanism

Control lever and linkage systems

Multiple controlling elements for single controlled element

C414S744500, C310S103000, C901S023000

Reexamination Certificate

active

06189404

ABSTRACT:

TECHNICAL FIELD
The present invention relates to a handling robot for use in a multiple chamber type manufacturing system such as for manufacturing semiconductors and LCDs in which a plurality of process chambers designed to constitute individual stations or stages are arranged around a transfer chamber, and a workpiece in the form of a sheet or thin plate such as a wafer to be worked on and processed in each of the process chambers is transferred by the handling robot from one of the process chambers to another via the transfer chamber.
BACKGROUND ART
A multiple chamber type semiconductor manufacturing system constructed as shown in
FIG. 1
includes a transfer chamber
1
around which a plurality of process chambers stations
2
a
,
2
b
.
2
c
,
2
d
,
2
e
, each comprising a process chamber, and a workpiece delivery station
3
for delivering workpieces to and from the outside are arranged. The inside of the transfer chamber
1
is normally held in vacuum by suitable vacuum equipment.
The transfer chamber
1
is constructed as shown in
FIG. 2
, having a handling robot A disposed rotatably in its central region. Constituting its peripheral wall, partition walls
5
that are opposed to the process chamber stations
2
a
,
2
b
,
2
c
,
2
d
,
2
e
and the workpiece delivery station
3
are formed with gates
6
, respectively, each of which provides an inlet and outlet for a workpiece into and out of each process chamber station. These gates
6
so as they may be opened and closed are provided with their respective opening/closing doors (not shown) arranged in opposition thereto, respectively, inside the transfer chamber
2
.
For the handling robot A is used typically a robot of double arm type, so called “frog leg” type, which is constructed as shown in FIG.
3
through
FIGS. 6A and 6B
.
As shown, the handling robot A has a pair of arms
7
a
and
7
b
of an identical length each of which is turnable about a center of rotation. It also has a pair of carrier tables
8
a
and
8
b
of an identical form, having their respective bases to each of which respective one ends of a pair of links
9
a
and
9
b
having an identical length are connected. The respective one ends of the two links
9
a
and
9
b
are connected to each of the two carrier tables
8
a
and
8
b
through a frog leg type carrier table posture (attitude) control mechanism so that the two links may turn completely symmetrically with respect to each of the carrier tables
8
a
and
8
b
. And, one of the two links connected to each of the carrier tables
8
a
and
8
b
is connected to one of the arms while the other link is connected to the other arm.
FIGS. 4A and 4B
show different forms of the frog leg type carrier table posture control mechanism mentioned above. Thus, as shown in
FIG. 4A
, the respective one ends of the two links
9
a
and
9
b
may be connected to each of the carrier tables
8
a
and
8
b
through a gear structure comprising a pair of gears
9
c
and
9
c
in mesh with each other so that the respective posture angles &thgr;R and &thgr;L of the links
9
a and
9
b
with respect to each of the carrier tables
8
a
and
8
b
may always be held identical to each other. This permits each of the carrier tables
8
a
and
8
b
to be oriented and to be moved in a radial direction of the transfer chamber
1
. For the links
9
a
and
9
b
to be connected to the carrier tables
8
a
and
8
b
, in lieu of the gears a crossed belting arrangement
9
d
may be employed as shown in FIG.
4
B.
FIG. 5
shows a conventional mechanism for turning the arms
7
a
and
7
b
independently of each other. The bases of the arms
7
a
and
7
b
are each in the form of a ring and are constituted with ring bosses
10
a
and
10
b
, respectively, which are positioned coaxially about the center of rotation and supported turnably with respect to the transfer chamber
1
.
Inside of each of the ring bosses
10
a
and
10
b
is arranged arranged a disk boss
11
a
,
11
b
coaxially therewith and opposed thereto, respectively. Each pair of the ring boss and the disk boss
10
a
and
11
a
,
10
b
and
11
b
that are opposed to each other are magnetically coupled together with each of a magnetic coupling
12
a
,
12
b
in the rotary direction.
The rotary shafts
13
a
and
13
b
of the disk bosses
11
a
and
11
b
are arranged coaxially with each other and are connected to the output sections of the motor units
14
a
and
14
b
, respectively, which are in turn supported coaxially with each other and axially deviated in position from one to the other on a frame
1
a
of the transfer chamber
1
. Here, the rotary shaft
13
b
of one motor unit
14
b
is elongated and arranged to pass through the other motor unit
14
a
and then to continue to extend upwards.
The motor units
14
a
and
14
b
may each be an integral combination of an AC servo motor
15
and a reducer
16
using a harmonic drive (a trade name, the representation which will not be repeated hereafter) in which the output sections of the reducers
16
and
16
are connected to the base ends of the rotary shafts
13
a
and
13
b
, respectively. Because once the arms
7
a
and
7
b
are positioned the transfer chamber
1
is to be maintained in a vacuum state, partition wall
17
is provided between the ring bosses
10
a
,
11
b
and the disk bosses
11
a
,
11
b.
FIGS. 6A and 6B
are used to describe an operation of the handling robot A. When the two arms
7
a
and
7
b
lie at diametrically opposed, symmetrical positions about the center of rotation as shown in
FIG. 6A
, the two links
9
a
and
9
b
will each have had turned to have its two legs opened at maximum with respect to the carrier tables
8
a
and
8
b
. The two carrier tables
8
a
and
8
b
will then have been moved towards the center of rotation or turning.
In this state, turning the two arms
7
a
and
7
b
in a given direction will cause the two carrier tables
8
a
and
8
b
to turn about the center of rotation while maintaining their radial positions. Conversely, turning the two arms
7
a
and
7
b
from the state shown in
FIG. 6A
in opposite directions such as to have them approach each other will cause the one carrier table
8
a
of the position where the angle the arm
7
a
makes with the arm
7
b
is decreasing to be pushed by the links
9
a
and
9
b
to move to project radially outwards and thus to be plunged or forced into the process chamber of the one of stations
2
a
,
2
b
,
2
c
,
2
d
and
2
e
that is adjacent thereto radially outside of the transfer chamber
1
as shown in FIG.
6
B.
In this case, while the other carrier table is moved towards the center of rotation or turning, the distance of this movement will be small because of the angles the arms
7
a
and
7
b
are making with the links
9
a
and
9
b.
In the conventional handling robot described, a plurality of coaxial drive shafts must be provided and a motor unit is combined with a load by using, for example, a hollow shaft, as shown in FIG.
5
. For these reasons, an elongated path of power transmission is entailed. There may thus result a positioning inaccuracy and a twisting that tend to produce vibrations. In order to avoid these inconveniences, it is desirable to shorten the path of power transmission as much as possible.
As a related prior art, there also exists a handling robot that makes use of a direct drive type motor operated in a vacuum as shown in Japanese Patent Literature No. Hei 8-506771 A in which a pair of motors are arranged coaxially and vertically up and down with their output shafts oriented in a same direction. The upper motor is hollow into which the output shaft of the lower motor is inserted. Thus, the output shaft of the lower motor is again necessarily elongated and also to that extent there may still arise a problem of twisting vibrations. A further problem involved in this type of the prior art is the need to use a special material that less emits gases for windings that constitute the motors, and such components and parts as sensors and bearings.
In an attempt to meet with these problems

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