Cleaning and liquid contact with solids – Apparatus – Sequential work treating receptacles or stations with means...
Reexamination Certificate
2000-11-30
2003-04-08
Stinson, Frankie L. (Department: 1746)
Cleaning and liquid contact with solids
Apparatus
Sequential work treating receptacles or stations with means...
C134S084000, C134S133000, C134S137000, C134S902000
Reexamination Certificate
active
06543461
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to handling and robotics systems, in general, and to such in semiconductor processing control systems, in particular.
BACKGROUND OF THE INVENTION
Reference is made to
FIG. 1
, which illustrates a prior art process environment
10
in a semiconductor fabrication plant. In general, process environment
10
comprises a process unit
2
, such as a chemical mechanical polisher, at least one load/unload cassette station
4
(two are shown), an integrated metrology tool
6
and a robot
8
.
The robot
8
transfers wafers to and from both the processing unit
2
and the cassette stations
4
. However, the integrated metrology tool
6
requires its own handling system in order to transfer the wafer to be measured from the robot
8
to a measuring location on tool
6
and vice versa.
FIGS. 2A
,
2
B,
2
C,
2
D,
2
E and
2
F illustrate the operation of tool
6
and robot
8
using a handling system
16
to work with an integrated metrology tool having a measuring unit
15
. One exemplary process environment uses the NOVASCAN 210 integrated metrology tool, commercially available from Nova Measuring Instruments Ltd. of Rehovot, Israel, and its handling system. The handling system
16
is composed of a bent arm
17
connected to a gripper
18
. The latter can be any gripper that can hold a wafer, such as a vacuum gripper.
The arm
17
slides vertically on a vertical rail
14
and reaches above the measuring unit
15
in order to place a new wafer in a measuring position and/or to return a measured wafer to the robot
8
. Between the uppermost position of gripper
18
and measuring unit
15
there is a supporting station
19
comprised of two supporting beams
24
and
25
, each of which has a supporting base
26
. Supporting beams
24
and
25
are connected to a rail
30
by a relative motion unit
32
. Unit
32
is designed to provide relative motion to supporting beams
24
and
25
such that they move toward and away from each other, as indicated by arrows
34
and
36
. A coupling member
54
connects supporting station
19
to the measuring unit
15
.
As shown in
FIG. 2B
, with supporting beams
24
and
25
in their most separated positions, gripper
18
can freely pass through the buffer station
22
, even when loaded with a wafer. As shown in
FIG. 2C
, with supporting beams
24
and
25
in their closest positions, a wafer can be held on each of supporting base
26
and gripper
18
cannot pass through.
In operation, and as shown in
FIG. 2D
, the robot
8
arrives at integrated tool
6
loaded with a new wafer W on an arm
9
. At this point, handling system
16
is waiting in its uppermost position. Robot
8
places the wafer W on supporting bases
26
, after which, as shown in
FIG. 2E
, handling system
16
moves down and picks up the wafer W. Robot
8
then leaves integrated tool
6
to conduct other missions while handling system
16
, loaded with the wafer W, continues down, until, as shown in
FIG. 2E
, it places the wafer, working surface down, in a measuring position on the measuring unit
15
. Typically, the measuring position includes supports that support the wafer on its edges (not shown). Since supporting beams
24
and
25
have moved towards and away from the plane of the paper, the supporting station
19
is shown in
FIG. 2F
with dashed lines.
It is noted that robot
8
leaves tool
6
empty and must arrive at tool
6
unloaded in order to take back a measured wafer. Thus, robot
8
is not optimally exploited, i.e., a disadvantage considering that the robot
8
is the “bottle neck” in process environment
10
(FIG.
1
).
Prior art systems solve this problem in multiple ways. One exemplary robot is the DBM 2400 series of Equipe Technologies, Mountain-View, Calif., USA. This robot has two separate arms. A second exemplary robot is the PerMer 6100 robot of Cybeq Systems, Sunnyvale, Calif., USA. The robot can hold two wafers, one on each side of its arm, and rotates the arm 180 degrees in order to switch wafers. For both prior art systems, the robot arrives at the supporting station loaded with a new wafer, and the free arm or side faces the supporting station. The free arm (side) loads a processed wafer from the supporting station, after which, the arm (side) with the new wafer is loaded onto the supporting station. The robot then returns loaded with the processed wafer.
It will be appreciated that these solutions require additional footprint since, during their operation, the two arms (sides) are loaded with both new and processed wafers. This may be a drawback in crowded processing environments.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to overcome the aforementioned limitations of the prior art.
There is thus provided in accordance with a preferred embodiment of the present invention a buffer station for an article handling system, the handling system having a general path along which it moves when handling the article, the buffer station comprising at least two supporting assemblies comprising supporting elements forming a supporting plane each capable of supporting an article within said supporting plane and located so as to support said article within said general path, at least two receptacles for liquid in which said at least two supporting assemblies are disposed and at least two drivers associated with said at least two supporting assemblies and said receptacles for shifting them in and out of said general path.
In accordance with a preferred embodiment of the present invention the supporting elements include at least two supporting bases each capable of holding a wafer thereon when the supporting elements are in the first mode.
There is also in accordance with a preferred embodiment of the present invention a buffer station for a wafer handling system, the handling system having a general path along which it moves when handling the wafer, the buffer station including at least two pairs of supporting elements each capable of supporting at least one wafer therebetween and located so as to support the wafer within the general path, a receptacle in which at least one of the pairs of supporting elements are disposed, the receptacle being at least partially filled with a liquid and adapted to hold at least one wafer at least partially submerged in the liquid, and one motion unit per pair of supporting elements for shifting its associated pair of supporting elements in and out of the general path and when the supporting elements are in the general path, for providing relative motion to its associated pair of supporting elements such that, in a first mode, the supporting elements support the wafer within the general path and, in a second mode, the supporting elements are sufficiently separated so as not to disturb the motion of the handling system when the handling system holds a wafer.
In accordance with a preferred embodiment of the present invention each of the supporting elements includes at least one supporting base each capable of holding a wafer thereon when the supporting elements are in the first mode.
Further in accordance with a preferred embodiment of the present invention the at least one supporting base includes two supporting bases.
Still further in accordance with a preferred embodiment of the present invention the at least two pairs of supporting elements include at least three pairs of supporting elements.
Additionally in accordance with a preferred embodiment of the present invention a liquid reservoir is in fluid communication with the receptacle.
In accordance with a preferred embodiment of the present invention a recirculation conduit is in fluid communication with the receptacle and the liquid reservoir, adapted to recirculate a liquid between the receptacle and the liquid reservoir. The liquid reservoir may be a source of purified, e.g. distilled water.
Further in accordance with a preferred embodiment of the present invention the receptacle includes a flexible, foldable gate, which when closed substantially seals flow of liquid from the receptacle
Dvir Eran
Haimovich Eli
Dekel Patent Ltd.
Klein David
Nova Measuring Instruments Ltd.
Stinson Frankie L.
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