Atmospheric wafer transfer module with nest for wafer...

Details Atmospheric wafer transfer module with nest for wafer... Atmospheric wafer transfer module with nest for wafer...

1999-06-29

2001-06-12

Bratlie, Steven A. (Department: 3652)

Material or article handling

Apparatus for moving material between zones having different...

C414S937000, C414S939000

Reexamination Certificate

active

06244811

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to transferring wafers among modules of semiconductor processing equipment, and more particularly to nesting certain modules of the equipment, and methods of implementing such nesting, to facilitate transfer of wafers among separate chambers of semiconductor processing equipment while reducing the area footprint occupied by the equipment.
2. Description of the Related Art
In the manufacture of semiconductor devices, process chambers are interfaced to permit transfer of wafers or substrates, for example, between the interfaced chambers. Such transfer is via transport modules that move the wafers, for example, through slots or ports that are provided in the adjacent walls of the interfaced chambers. For example, transport modules are generally used in conjunction with a variety of substrate processing modules, which may include semiconductor etching systems, material deposition systems, and flat panel display etching systems. Due to the growing demands for cleanliness and high processing precision, there has been a growing need to reduce the amount of human interaction during and between processing steps. This need has been partially met with the implementation of vacuum transport modules which operate as an intermediate handling apparatus (typically maintained at a reduced pressure, e.g., vacuum conditions). By way of example, a vacuum transport module may be physically located between one or more clean room storage facilities where substrates are stored, and multiple substrate processing modules where the substrates are actually processed, e.g., etched or have deposition performed thereon. In this manner, when a substrate is required for processing, a robot arm located within the transport module may be employed to retrieve a selected substrate from storage and place it into one of the multiple processing modules.
As is well known to those skilled in the art, the arrangement of transport modules to “transport” substrates among multiple storage facilities and processing modules is frequently referred to as a “cluster tool architecture” system.
FIG. 1A
depicts a typical semiconductor process cluster architecture
100
illustrating the various chambers that interface with a vacuum transport module
106
. Vacuum transport module
106
is shown coupled to three processing modules
108
a
-
108
c
which may be individually optimized to perform various fabrication processes. By way of example, processing modules
108
a
-
108
c
may be implemented to perform transformer coupled plasma (TCP) substrate etching, layer depositions, and/or sputtering.
Connected to vacuum transport module
106
is a load lock
104
that may be implemented to introduce substrates into vacuum transport module
106
. Load lock
104
may be coupled to a clean room
102
where substrates are stored. In addition to being a retrieving and serving mechanism, load lock
104
also serves as a pressure-varying interface between vacuum transport module
106
and clean room
102
. Therefore, vacuum transport module
106
may be kept at a constant pressure (e.g., vacuum), while clean room
102
is kept at atmospheric pressure. Consistent with the growing demands for cleanliness and high processing precision, the amount of human interaction during and between processing steps has been reduced by the use of robots
110
to transfer the wafers from the clean room
102
to the load lock
104
.
FIG. 1B
depicts a prior art robot
110
mounted along a track
112
between wafer cassettes
114
and two load locks
104
provided in the clean room
102
. The clean room
102
, with the cassettes
114
and the robot
110
, is maintained at atmospheric pressure, thus these items may be referred to as parts of an atmospheric transfer module
116
. The robot
110
can be moved transversely along the linear track
112
between ends
118
a
and
118
b
to facilitate removing a wafer
120
straight out of one of the cassettes
114
. That is, during removal the wafer
120
must be aligned with a wafer transfer axis
122
that extends in the direction of a y-axis. The aligned transfer has been used to avoid difficulties experienced in the past in controlling robots during wafer transfer, e.g., when the base of the robot is rotated (theta motion) on a vertical axis at the same time as the arms of the robot are moved in an extend motion.
The load locks
104
are mounted opposite to the cassettes
114
and have front faces, or wafer transfer faces,
124
that are parallel to the track
112
and extend in the direction of an x-axis. Generally, there is a minimum distance (along the wafer transfer axis
122
of the load lock
104
) required between the robot
110
(hence between the track
112
) and the load lock
104
into which a wafer
120
is to be transferred. This minimum distance is the minimum distance required by the robot
110
to transfer a wafer
120
straight into the load lock port without rotation of the robot
110
on a robot central axis of rotation
126
, and may be referred to as a wafer transfer distance, or wafer feed distance. The wafer feed distance is depicted by the dimension line
127
having opposite arrowheads and extending between the track
112
and the face
124
of the load lock
104
. The wafer feed line, or dimension line,
127
is shown extending in the direction of the y-axis parallel to the wafer transfer axis
122
, and both the line
127
and the axis
122
are perpendicular to the track
112
and to the y-axis.
The size of the robot track
112
, and the need to lubricate the robot track
112
, have caused problems in that the robot track
112
is relatively long in the direction of the y-axis. Also, lubrication on the track
112
is exposed, and is thus a “dirty” element in the otherwise “clean”, clean room
102
. Further, the length of the wafer transfer distance
127
must separate the robot
110
, or the track
112
, firm the face
124
of the load locks
104
. In the past the length of the entire wafer feed distance, or dimension line,
127
extending in the direction of the y-axis has been between the track
112
and the face
124
. A footprint of the combined atmospheric transfer module
116
and vacuum transfer module
106
is generally defined by the floor area occupied by these modules
106
and
116
, such that the footprint is proportional to floor area dimensions along the x and y axes. Thus, the relatively long length of the track
112
in the direction of the x-axis, and the length of the entire wafer transfer distance
127
extending in the direction of the y axis, contribute to the size of the footprint of these modules
106
and
116
. As shown in
FIGS. 1B and 1C
, in the direction of the y-axis, the length of a footprint dimension line
130
contributes to the size of the footprint. It is observed that the length of the entire wafer transfer distance
127
extending in the direction of the y-axis is part of the footprint dimension line
130
, for example. In view of the increased cost of building and supporting clean run environments for such equipment, there is a great need to reduce the resulting footprint. In addition, if equipment footprint can be made smaller, production can be increased using the same amount of clean room space.
In view of the forgoing, what is needed is a robot that avoids the need for a track that is relatively long in the direction of the y-axis, and that does not present a track lubrication problem. Also, since there is a minimum length of the wafer transfer distance that must separate a robot from a wafer transfer face of a load lock, what is needed is a way of avoiding having that entire minimum length extend in the direction of the y-axis, such that the length of a footprint dimension line
130
extending in the direction of the y-axis, for example, does not include such entire minimum length. Further, in operations for transferring wafers into load locks, it should not be necessary to rotate the base of the robot on a vertical axis at the same time as the arms of

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