Fluent material handling – with receiver or receiver coacting mea – Processes – Gas or variation of gaseous condition in receiver
Reexamination Certificate
2002-01-11
2004-03-09
Huson, Gregory (Department: 3652)
Fluent material handling, with receiver or receiver coacting mea
Processes
Gas or variation of gaseous condition in receiver
C141S059000, C141S066000, C141S098000, C414S217100, C414S935000
Reexamination Certificate
active
06701972
ABSTRACT:
DESCRIPTION OF THE INVENTION
1. Field of the Invention
The present invention is generally directed to apparatuses, systems, and methods associated with substrate processing. Certain aspects of the present invention are directed to a load lock apparatus, systems, and methods useable in semiconductor wafer processing and/or processing of other substrates, such as those intended for flat panel displays. Other aspects may be related to processing chambers for substrate processing.
2. Background of the Invention
In order to produce semiconductor wafers, manufactures start with an unprocessed substrate and perform various processing steps to convert the substrate to a semiconductor wafer. These process may include scrubbing the substrate to provide a clean surface, etching, depositing, or plating the substrate, and cooling the substrate to produce the finished semiconductor wafer. Some of these steps may be grouped together and performed within a single semiconductor tool.
A semiconductor tool may include a central transfer chamber with a plurality of processing chambers mounted around the periphery of the central transfer chamber. A robot arm may be located inside the central transfer chamber to move the substrate from one processing station to the next. In general, most, if not all of the processing stations and the central transfer chamber are maintained at or near vacuum conditions. The vacuum condition provides many benefits including the prevention of undesirable particles or other impurities being deposited onto the substrate.
For most semiconductor tools, the supply of substrates is maintained outside of the semiconductor tool in an area at or near atmospheric pressure. As such, semiconductor manufacturing facilities typically include an apparatus that allows transfer of substrates from this atmospheric condition to the vacuum condition of the semiconductor tool. Load lock apparatuses have been used to allow this type of transfer.
Some conventional load lock apparatuses generally include two gate valves, one being configured to open into the central transfer chamber and the other being configured to open to allow insertion of the substrates from a storage location. A vacuum pump attached to the load lock provides a vacuum condition after the substrates have been inserted into the load lock apparatus. Once vacuum is provided in the load lock apparatus, the gate valve leading to the central transfer chamber is opened and the substrates can be moved from the load lock into the central chamber. After all of the processing has occurred, the semiconductor wafers (substrates) are moved back into the load lock apparatus. At this time, the vacuum is removed, the load lock is returned to atmospheric pressure, and the semiconductor wafers may be removed.
Current load locks typically are designed to transfer several substrates at a single time into the semiconductor tool. These load locks typically have a volume between 6 and 10 liters. Because the volume of the load locks are large, it can take several seconds or even minutes to cycle between atmospheric pressure and vacuum conditions. This, in turn, limits the number of semiconductor wafers that can be produced with the semiconductor tool. For example, typical through rates of semiconductor tools range between 100 to 150 semiconductor wafers per hour, and attempts to improve these rates are limited by the pressure cycling of the load locks. In addition, these load locks often require large amounts of gas to be added or withdrawn quickly, which creates potential problems of damaging or contaminating the wafers.
One possible approach to increasing the number of semiconductor wafers produced per hour is to decrease the size of load lock and thereby reduce the pressure cycling time. Decreasing the size of the load lock, however, presents a number of technical challenges.
SUMMARY
The present invention is directed to systems, apparatus, and methods that may obviate one or more of the limitations of the related art. In particular, the present invention could be directed to systems and methods that might be used in substrate processing for transferring processed and/or unprocessed substrates, such as wafers or substrates intended for flat panel display.
One aspect relates to a system comprising a load lock apparatus having an interior configured to receive an object. At least one inlet valve may be flow coupled to the interior of the load lock apparatus, and at least one outlet valve may also be flow coupled to the interior of the load lock apparatus. A controller may be configured to selectively control opening and closing of the at least one inlet valve.
The controller may be configured to open the at least one inlet valve and leave the one inlet valve open while the at least one outlet valve is closed for a predetermined period of time so as to substantially equilibrate pressure in the interior with pressure exterior of the load lock apparatus. The controller may also be configured to open the at least one outlet valve after the predetermined period of time to prevent over pressurization of the interior.
The load lock apparatus may comprise at least one opening permitting insertion of the object into the interior of the apparatus. Optionally, the load lock apparatus may further comprise at least one gate valve configured to selectively close the opening. The controller may be configured to open the at least one gate valve after the at least one outlet valve is opened.
The predetermined period of time may range from about 0.1 seconds to about 4 seconds, such as, for example, about 1.5 seconds.
In another aspect, there is a system comprising a load lock apparatus including an interior configured to receive an object and a gas supply flow path configured to provide flow of gas from a gas source to the interior of the load lock apparatus. At least one inlet valve may be configured to control flow of gas through the gas supply flow path. A pressure limiter (e.g., pressure relief valve, pressure switch, mass flow controller, or other pressure limiter) may be associated with the gas supply flow path to maintain pressure of gas flowing to the interior of the load lock apparatus below a predetermined maximum pressure. The predetermined maximum pressure may be, for example, greater than pressure external to the load lock apparatus.
Yet another aspect relates to a system comprising a load lock apparatus including an interior configured to receive an object, a gas supply flow path configured to provide flow of gas from a gas source to the interior of the load lock apparatus, at least one inlet valve configured to control flow of gas through the gas supply flow path, and a gas outlet flow path configured to provide flow of gas from the interior of the load lock apparatus. At least one outlet valve may be configured to control flow of gas through the gas outlet flow path. A check valve may be associated with the gas outlet flow path downstream from the at least one outlet valve to prevent backflow of gas while the at least one outlet valve is open.
In another aspect, there is a system comprising a load lock apparatus including an interior, at least first and second inlets arranged to provide flow of gas to the interior, and an object receiving mechanism located within the interior to receive an object. The first inlet may be arranged above the object receiving mechanism and the second inlet may be arranged below the object receiving mechanism. A gas supply flow path may be configured to provide flow of gas from a gas source to the interior of the load lock apparatus via the at least first and second inlets. At least one inlet valve may be configured to control flow of gas through the gas supply flow path.
The at least first and second inlets may further comprise a third inlet arranged below the object receiving mechanism.
The at least one inlet valve may comprise a first inlet valve and a second inlet valve. The first inlet valve may be flow coupled to the first inlet and the second inlet valve may be flow coupled to the second inlet. Alternatively, th
Dickinson Colin John
Murphy Daimhin Paul
deVore Peter
Huson Gregory
The BOC Group Inc.
Zebrak Ira Lee
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