Material or article handling – Device for emptying portable receptacle – Nongravity type
Reexamination Certificate
2000-06-06
2002-06-25
Hess, Douglas (Department: 3651)
Material or article handling
Device for emptying portable receptacle
Nongravity type
C414S941000
Reexamination Certificate
active
06409453
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to the storage and transfer of wafers typically used in the fabrication of integrated circuits. Specifically, the invention relates to the end effector, or blade, of a wafer handler used to transfer wafers through and between chambers in a system, for processing the wafers.
2. Background of the Related Art
Vacuum processing systems for processing 100 mm, 200 mm, 300 mm or other diameter wafers are generally known. Typically, such vacuum processing systems have a centralized transfer chamber mounted on a monolith platform. The transfer chamber is the center of activity for the movement of wafers being processed in the system. One or more process chambers mount on the transfer chamber at slit valves through which wafers are passed by a wafer handler, or robot, in the transfer chamber. The valves close in order to isolate the process chambers while wafers are being processed therein. The wafer handler transfers the wafers through the transfer chamber and between the various other chambers attached to the transfer chamber.
Some common transfer chambers have facets to accommodate four to six chambers. The process chambers include rapid thermal processing (RTP) chambers, physical vapor deposition (PVD) chambers, chemical vapor deposition (CVD) chambers, etch chambers, etc. Physically, the process chambers are either supported by the transfer chamber and its platform or are supported on their own platform. Inside the system, the transfer chamber is typically held at a constant vacuum; whereas, the process chambers may be pumped to a greater vacuum for performing their respective processes. Afterward, the chamber pressure must be returned to the level in the transfer chamber before opening the valve to permit access between the chambers.
For some vacuum processing systems, such as the Centura ™ system from Applied Materials, Inc., access to the transfer chamber for wafers from the exterior of the system, or from the manufacturing facility, is typically through one or more load lock chambers. For some other vacuum processing systems, such as the Endura ™ system from Applied Materials, Inc., a series of other chambers, including a buffer chamber, are provided between the transfer chamber and the load lock chambers. Thus, the transferring of the wafers through the vacuum in the system proceeds in stages, with the buffer chamber typically operating at about 1×10
−6
torr, the transfer chamber typically operating at about 1×10
−7
torr and the process chambers typically operating at about 1×10
−9
torr in the case of physical vapor deposition process chambers.
The buffer chamber is an intermediate transfer chamber that may have optional preprocessing or post-processing chambers attached to it for performing additional processing steps on the wafers. Additionally, a pre-clean chamber and a cool-down chamber are interposed between the buffer chamber and the transfer chamber. Since the buffer chamber and the transfer chamber are typically held at different vacuum levels, the pre-clean chamber transitions the wafers from the vacuum level of the buffer chamber to the vacuum level of the transfer chamber in addition to cleaning the wafers in preparation for processing in the process chambers. After undergoing the primary process, the cool-down chambers transition the wafers from the vacuum level of the transfer chamber to the vacuum level of tie buffer chamber while cooling the wafers. Another wafer handler, similar to the one disposed in the transfer chamber, is disposed within the buffer chamber in order to transfer the wafers through the buffer chamber and between the various chambers attached thereto.
The load lock chambers cycle between the pressure level of the ambient environment and the pressure level in either the transfer chamber or the buffer chamber in order for the wafers to be passed therebetween, so the-load lock chambers transition the wafers between the atmosphere pressure of a very clean environment to the vacuum of the system. The load lock chambers attach to a mini-environment which transfers wafers in a very clean environment at atmospheric pressure from wafer pods to the load lock chambers. Thus, the mini-environment has another wafer handler for transferring the wafers.
The wafer handlers in the transfer chamber and the buffer chamber are typically very similar, if not identical. An example of such a wafer handler
10
is shown in
FIGS. 1
a
and
1
b.
the wafer handler
10
is capable of rotational movement, but not translational movement since it is fixed in the center of its chamber. The wafer handler
10
has an end effector
12
,
14
, or blade, attached to an arm assembly
16
attached to the rotating portion
18
of the wafer handler
10
. A wafer sits on the end effector
12
,
14
in order to be transferred. A sensor beam may be projected through the wafer sense hole
15
in order to sense the presence of a wafer on the end effector
12
,
14
. The sensor beam may be an infrared beam directed at a detector. The wafer sense hole
15
is typically a standard size, and may be about 0.87 inches, or 22 mm, in radius. The arm assembly
16
moves the end effector
12
,
14
radially outward from and inward towards the wafer handler
10
in order to insert a wafer into or retrieve a wafer from a chamber.
The wafer handler in the mini-environment is typically different from those in the transfer chamber or the buffer chamber, since it is usually capable of translational movement as well as rotational movement. A top view of an example of such a wafer handler
20
is shown in
FIG. 1
c.
The wafer handler
20
is typically track mounted so that it can move back and forth inside the mini-environment in order to service each of the pod loaders and load lock chambers attached thereto. The wafer handler
20
has an end effector
22
attached to an arm assembly
24
attached to the rotating portion
26
of the wafer handler
20
. A wafer sits on the end effector
22
in order to be transferred. The arm assembly
24
moves the end effector
22
radially outward from and inward towards the rotating portion
26
. The contact portion
25
of the end effector
22
is typically the only part of the end effector
22
that contacts the wafer. The contact portion
25
typically uses vacuum suction to hold the wafer. Vacuum suction Is not a practical method to hold a wafer inside the transfer chamber or the buffer chamber, however, since these areas are already subject to a vacuum, which would lessen the hold of the vacuum suction. Additionally, it is desirable to have only one style of end effector, which may be used with all wafer handlers, in order to reduce the number of parts used in a processing system.
The end effector
14
, shown in
FIG. 1
a,
has a constant width from the end effector mounting
27
, or robot blade wrist, to the free end. A short recess in the free end forms two projections at the free end. A wafer is supported on small shelves located near the free end on the two projections and near the end fixed at the mounting
27
. The shelf supports may provide no more than about 120 mils of space between the wafer and the end effector
14
. For 300 mm wafers, the width poses a problem with the exclusion zones defined by the SEMI 300 mm Wafer Carrier and Interface Standard, a standard set by Semiconductor Equipment and Materials International to create, inter alia, an industry standard configuration for a wafer carrier.
The exclusion zones are areas within a 300 mm wafer carrier or holder reserved for the wafer carrier to support the wafer and are illustrated by the areas
100
,
102
as shown in FIG.
4
. The exclusion zones
100
are about 29 mm wide, 170 mm long and 250 mm apart. The exclusion zones
102
are about 25 mm wide, 32 mm long and 100 mm apart. The center of a wafer will be almost directly in the geometric center of the combined exclusion zones
100
, and offset from the exclusion zones
102
by about 120 mm. An end effector may n
Brodine Jeff
Marohl Dan
Applied Materials Inc.
Hess Douglas
Moser Patterson & Sheridan LLP
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