Electric heating – Heating devices – Combined with container – enclosure – or support for material...
Reexamination Certificate
2000-02-17
2002-11-26
Walberg, Teresa (Department: 3742)
Electric heating
Heating devices
Combined with container, enclosure, or support for material...
C219S405000, C219S411000, C118S724000, C118S050100, C392S416000
Reexamination Certificate
active
06486444
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to the storage and transfer of substrates typically used in the fabrication of electronic devices such as integrated circuits and flat panel displays. Specifically, the invention relates to a load-lock chamber and a pre-processing or post-processing storage rack used to transition substrates from one environment to another environment in a processing system.
2. Background of the Invention
Vacuum processing systems used in the fabrication of integrated circuits and flat panel displays are generally known. An example of a vacuum processing system
100
is shown in
FIGS. 1 and 2
. The vacuum processing system
100
typically has a centralized transfer chamber
102
mounted on a monolith platform or main frame structure
110
. One or more process chambers
106
are in communication with the transfer chamber
102
via access ports
105
and associated slit valves
107
. Substrates are passed through the system by a substrate handling robot
103
disposed in the transfer chamber
102
. The slit valves
107
isolate the process chambers
106
from each other and from the transfer chamber
102
while substrates are being processed. The transfer chamber
102
is typically held at a constant vacuum, while the process chambers
106
may be pumped to a greater or lesser vacuum than the transfer chamber
102
for performance of their respective processes. Afterward, the process chamber pressure returns to the level in the transfer chamber
102
before opening the slit valve
107
is opened to permit access between the chambers.
The substrate handling robot
103
disposed in transfer chamber
102
typically retrieves one or more unprocessed substrates from one or more load-lock chambers
112
connected to the transfer chamber
102
and places the substrates in the process chambers
106
. The load-lock chambers
112
selectively cycle between the pressure level of the ambient environment and the pressure level in the transfer chamber
102
to transition the substrates between atmospheric pressure and the vacuum environment of the transfer chamber
102
. The load-lock chambers
112
typically have a large volume and store multiple substrates. Typically, twelve to twenty-four substrates are stacked vertically in one or more substrate cassettes
109
disposed in load-lock chambers
112
. The substrate cassettes
109
typically include a plurality of substrate supports spaced vertically to permit a substrate handling robot blade
115
to reach under a substrate to remove or place a substrate. Substrates are typically loaded in and removed from the load-lock chamber
112
by either a staging robot
113
(shown in FIGS.
1
and
3
), or an operator at or near a frontend staging area
104
.
Typically, the front-end staging area
104
is maintained at or near ambient or atmospheric pressure. Accordingly, prior to transfer of substrates into or out of the loadlock chamber
112
, the atmospheric volume within the load-lock chamber
112
must be vented to atmospheric pressure before opening the valves of the load-lock chamber
112
. Similarly, before transfer of substrates between the load-lock chamber
112
and the transfer chamber
102
, the atmospheric volume within the load-lock chamber
112
must be evacuated to the low pressure maintained in the transfer chamber
102
. Because of the sizable volume within typical load-lock chambers
112
, a relatively lengthy amount of time is required to vent and then evacuate the load-lock chamber
112
before permitting access to the substrates by the substrate handling robot
103
This process may typically take approximately four (4) minutes to complete. During this time, the vacuum processing system
100
typically sits idle while awaiting the introduction of additional unprocessed substrates into the system.
It has been found that substantial production gains can be made by reducing the atmospheric volume within the load-lock chamber
112
serving the transfer chamber
102
. Accordingly, systems having single substrate load-lock chambers have been developed to reduce venting and evacuation time within the load-lock process chamber
112
, which has resulted in a reduction of process chamber idle time and an increase in production. One exemplary system of this type is shown in U.S. patent application Ser. No. 08/990,396, entitled “Single Wafer Load-lock Chamber For Pre-Processing And Post-Processing Wafers In A Vacuum Processing System,” filed on Feb. 15, 1997, which is incorporated herein by reference.
However, the reduction in the number of substrates housed in the load-lock chamber
112
requires that the substrates must be transferred quickly into and out of the load-lock chamber
112
. This can be problematic when substrates must be pre-heated prior to processing or cooled following processing before being replaced into a substrate cassette
109
. Unfortunately, a shorter transition time through the load-lock chamber
112
may prevent the load-lock chamber
112
from sufficiently pre-heating a substrate prior to processing or cooling a substrate following processing.
To accommodate this cooling and/or pre-heating process, existing systems have provided cooling and/or pre-heating chambers attached to the transfer chamber
102
. Because space may be limited on a typical transfer chamber
102
, such systems are required to forfeit a facet on which a processing chamber
106
could be mounted. Alternatively, systems may have limited throughput due to a limited number of preheating/cooling chambers mounted to the transfer chamber
102
and/or the amount of time required to perform the pre-processing/post processing procedures. In systems where heating and/or cooling members are integrated within the load-lock chamber
112
, throughput may be limited because a cooling process may require an extended cooling time beyond the time in which the substrate handling robot
103
can return to the load-lock chamber
112
to return a processed substrate or retrieve an unprocessed substrate for further processing. As a result, the system substrate transfer system is limited by the time required for the cooling process to be performed.
Accordingly, there is a need for a vacuum processing system that provides high throughput and pre-processing and/or post-processing processes. More particularly, there is a need for an integrated system having a load-lock chamber with an integrated staging, or storage rack mounted external to the transfer chamber for pre-processing and/or post-processing of substrates.
SUMMARY OF THE INVENTION
The present invention generally provides a vacuum apparatus for processing substrates, comprising a transfer chamber; one or more processing chambers in communication with the transfer chamber; a substrate handling robot disposed in the transfer chamber; and at least one load-lock chamber connected to the transfer chamber, with the load-lock chamber having one or more substrate support members for supporting one or more substrates. The apparatus preferably includes a substrate staging area and may further include a staging robot disposed in the staging area to load substrates into and remove substrates from the load-lock chamber.
In another aspect of the invention, the staging area may include one or more storage racks associated with the load-lock chamber for receiving and temporarily storing substrates. Further, the storage racks, preferably include at least a cooling element and are adapted to temporarily receive and cool substrates retrieved from the load-lock chamber following processing.
In another aspect of the invention, at least one of the storage racks may include a heating element adapted to pre-heat unprocessed substrates retrieved from the substrate cassette prior to processing. Further, the storage racks may include a cooling element and/or a heating element, each adapted to receive and process a substrate prior to transfer. Still further, the load-lock chamber may include a heating element disposed in connection therewith for pre-heating unpr
Colborne Kelly A.
Fairbairn Kevin
Grunes Howard E.
Lane Christopher
Applied Materials Inc.
Fuqua Shawntina T
Moser Patterson & Sheridan
Walberg Teresa
LandOfFree
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