Synchronous multiplexed near zero overhead architecture for vacuum processes
First Claim
1. A dual chamber apparatus for continuously processing a plurality of workpieces comprising:
- a common power source switchable between a first chamber and a second chamber, the first chamber for processing a second workpiece in a deep vacuum to completion therein when the power source is applied thereto and switched ON, a robot for removing at substantially atmospheric pressure a first workpiece from the second chamber after processing and reloading the second chamber with a third workpiece to be processed while the second workpiece is being processed in the first chamber, the second chamber for processing the third workpiece in a deep vacuum to completion therein when the power source is applied thereto and switched ON, the robot for removing at substantially atmospheric pressure the second workpiece from the first chamber after processing and reloading the first chamber with a fourth workpiece to be processed while the third workpiece is being processed in the second chamber, and a computer for repeatedly synchronously alternately controlling the power source application, the robot movement and the chamber processing as aforesaid.
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Accused Products
Abstract
Workpieces, such as, semiconductor wafers, are continuously manufactured by repetitively alternately switching a common radio frequency power source between a plurality of downstream or in-chamber processing reactors and actively processing one workpiece in a vacuum in an operating one of the processing chambers while simultaneously executing with a robot at atmospheric pressure the overhead tasks relative to next processing another workpiece in the other processing chamber. The active processing of the workpieces in alternate chambers does not overlap, and the robot starts and completes all of its preparatory tasks during the active processing step during the time when a chamber'"'"'s door is closed thereby providing virtual zero overhead. System architecture allows eliminating all redundant components other than the dual chambers which operate in parallel. For a modest cost increase for the second chamber throughput is trebled and overall costs significantly reduced. Preferred modes include switching a common microwave power source between the pair of processing chambers, pumping down with a common vacuum pump, and stabilizing the chamber pressure with a common throttle valve.
22 Citations
28 Claims
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1. A dual chamber apparatus for continuously processing a plurality of workpieces comprising:
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a common power source switchable between a first chamber and a second chamber, the first chamber for processing a second workpiece in a deep vacuum to completion therein when the power source is applied thereto and switched ON, a robot for removing at substantially atmospheric pressure a first workpiece from the second chamber after processing and reloading the second chamber with a third workpiece to be processed while the second workpiece is being processed in the first chamber, the second chamber for processing the third workpiece in a deep vacuum to completion therein when the power source is applied thereto and switched ON, the robot for removing at substantially atmospheric pressure the second workpiece from the first chamber after processing and reloading the first chamber with a fourth workpiece to be processed while the third workpiece is being processed in the second chamber, and a computer for repeatedly synchronously alternately controlling the power source application, the robot movement and the chamber processing as aforesaid. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
the robot having two grippers and alternately and synchronously finishes removing a fresh workpiece from a cassette with it one gripper ready for an exchange with it other gripper adjacent a chamber in which one of the workpieces has just finished processing and the chamber overhead is shorter than the process time.
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9. The apparatus of claim 8 wherein the computer is programmed to have a robot wait time of substantially zero between loading an unprocessed workpiece in one of the chambers and unloading a processed workpiece in the other of the chambers.
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10. The apparatus of claim 8 wherein the computer is programmed to have a robot wait time of near zero between loading an unprocessed workpiece in one of the chambers and unloading a processed workpiece in the other of the chambers.
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11. The apparatus of claim 1 further comprising:
two cassettes supported adjacent the chambers wherein all of the workpieces are alternately and synchronously removed from one cassette before processing and are returned to the other cassette after processing.
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12. The apparatus of claim 1 further comprising:
two cassettes supported adjacent the chambers wherein all of the workpieces are alternately and synchronously removed from one cassette before processing and are returned to their original slot in the same cassette after processing before any workpieces in the other cassette begin processing.
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13. The apparatus of claim 1 wherein a cassette is supported adjacent the chambers and the computer is programmed such that, alternately and synchronously, all of the odd numbered workpieces are processed in the second chamber and all of the even numbered workpieces are processed in the first chamber, but all workpieces are returned to their original slots in the single cassette.
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14. The apparatus of claim 1 further comprising:
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a dedicated chamber process gas vacuum pump coupled to a throttle valve during processing of a workpiece for stabilizing a chamber operating pressure, and a dedicated chamber pump-down vacuum pump bypassing the throttle valve during chamber pump-down.
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15. The apparatus of claim 1 further comprising;
a vent line for venting one chamber to atmosphere without disturbing the process gas flow in the other chamber.
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16. The apparatus of claim 15 wherein the vent line further comprises:
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a first vent line for initially slow venting the one chamber, and a second vent line for fast venting that chamber immediately thereafter.
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17. The apparatus of claim 16 wherein the first vent line further comprises a small orifice valve, and wherein the second vent line further comprises a large orifice valve, and further comprising a pressurized back-fill tank coupled to the vent lines for backfilling the chamber with a gas therefrom.
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18. The apparatus of claim 1 further comprising:
a gas line coupled to each chamber through which a gas is trickle purged for preventing air and moisture from entering a chamber while the chamber is vented to atmosphere.
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19. The apparatus of claim 1 wherein the vacuum lines further comprise:
a vacuum reservoir equivalent which prevents interaction between the chambers by isolating one chamber from the other when connecting both chambers to a single vacuum pump.
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20. The apparatus of claim 19 wherein the vacuum reservoir equivalent comprises a volume sufficient to preventing a burst of air upon venting one chamber from traveling down a vacuum line to the vacuum pump and back up another line to the chamber processing the workpiece.
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21. The apparatus of claim 20 wherein the vacuum reservoir equivalent further comprises:
vacuum lines which are long enough and big enough in diameter so that the air burst pressure wil equalize and expand to fill the space and will be very low by the time it reaches the pump in the line on the side that is pumping down.
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22. The apparatus of claim 20 wherein the vacuum reservoir equivalent further comprises
a small orifice valve for slowing the initial burst of air from the chamber being pumped down by initially passing the air burst therethrough, and a large orifice valve for providing a higher conductance to rapidly pump the remaining air from the chamber by passing the air burst therethrough a second or two thereafter. -
23. The apparatus of claim 1 further comprising:
a fiber optic line, through which light emissions generated by the process is transmitted, coupled between each chamber and a monochromator which receives the light for detecting the end point of the process.
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24. The apparatus of claim 23 further comprising:
the fiber optic line from each chamber coupled to a switchless optical junction wherein the signals from the two chambers are summed as the light emissions from each chamber, which occurs only while a respective one of the chambers is processing, is passed therethrough.
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25. The apparatus of claim 1 wherein the power source and dual chambers are constructed and configured into a single first state processor and dual second stage processor further comprising:
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the first stage supported adjacent the dual chambers of the second stage and having an output coupled to a first path coupled to one of the chambers and a second path coupled to the other chamber and selectively directable to either one of the paths, a valve in each path for selectively opening and closing each path, wherein when the output of the first stage is directed to the first path the second path is closed, and the second workpiece is processing in the first chamber to completion while the first workpiece is simultaneously removed after processing from the second chamber and replaced with the third workpiece to be processed, and wherein when the output of the first stage is directed to the second path the first path is closed, and the third workpiece is processing in the second chamber to completion while the second workpiece is simultaneously removed from the first chamber and replaced with the fourth workpiece to be processed.
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26. The apparatus of claim 25 further comprising a single plasma applicator selectively communicating plasma excited process gases to either the first path or the second path.
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27. The apparatus of claim 26 further comprising:
a common diverter plate mounted adjacent the output for alternately blocking the output into the path of one of the pair of processing chambers.
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28. The apparatus of claim 1 wherein each workpiece is a cassette containing multiple substrates and the robot is configured to transfer the cassette into one of the chambers, and each of the chambers is configured to receive and process a cassette of substrates.
Specification