Synchronous multiplexed near zero overhead architecture for vacuum processes
First Claim
1. A method of continuously processing a plurality of workpieces comprising the steps of:
- supplying radio frequency power from a common power source to one of a pair plasma sources of a corresponding pair of processing chambers, plasma treating a workpiece in a deep vacuum solely in the one processing chamber while simultaneously executing at substantially atmospheric pressure substantially all post-processing and pre-processing overhead tasks relative to plasma treating another workpiece in the other processing chamber, and then reversing the aforesaid steps by supplying power from the common power source to the other plasma source processing chamber and plasma treating the other workpiece in a deep vacuum solely therein while simultaneously executing at substantially atmospheric pressure substantially all overhead tasks relative to plasma treating a third workpiece in the one processing chamber, and continuously repeating all of the aforesaid steps in sequence.
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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.
76 Citations
45 Claims
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1. A method of continuously processing a plurality of workpieces comprising the steps of:
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supplying radio frequency power from a common power source to one of a pair plasma sources of a corresponding pair of processing chambers, plasma treating a workpiece in a deep vacuum solely in the one processing chamber while simultaneously executing at substantially atmospheric pressure substantially all post-processing and pre-processing overhead tasks relative to plasma treating another workpiece in the other processing chamber, and then reversing the aforesaid steps by supplying power from the common power source to the other plasma source processing chamber and plasma treating the other workpiece in a deep vacuum solely therein while simultaneously executing at substantially atmospheric pressure substantially all overhead tasks relative to plasma treating a third workpiece in the one processing chamber, and continuously repeating all of the aforesaid steps in sequence. - View Dependent Claims (2, 3)
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4. A method of continuously manufacturing a plurality of workpieces comprising the steps of:
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alternately switching a common radio frequency power source between a plurality of plasma sources of a corresponding plurality of processing chambers, and plasma etching a workpiece in a deep vacuum in an operating one of the processing chambers while simultaneously executing at substantially atmospheric pressure the post-processing and pre-processing overhead tasks relative to next plasma etching another workpiece in a non-operating other one of the processing chambers, and continuously repeating all of the aforesaid steps in sequence. - View Dependent Claims (5, 6)
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7. A continuous method of processing workpieces through dual processing chambers comprising, in sequence, the steps of:
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(a) initially loading a first chamber with a first workpiece to be treated for removal of photoresist, (b) switching a remote plasma supply to the first chamber ON and to the second chamber OFF, (c) removing photoresist from the workpiece in the first chamber while simultaneously initially loading the second chamber with a second workpiece, (d) switching the remote plasma supply to the first chamber OFF and to the second chamber ON, (e) removing photoresist from the second workpiece in the second chamber to completion while simultaneously removing the first workpiece from the first chamber and reloading the first chamber with a third workpiece, (f) switching the remote plasma supply to the first chamber ON and to the second chamber OFF, (g) removing photoresist from the third workpiece in the first chamber while simultaneously removing the second workpiece from the second chamber and reloading the second chamber with a fourth workpiece, and (h) continuously repeating steps (d)-(g) with respect to each succeeding workpiece in sequence. - View Dependent Claims (8, 9)
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10. A continuous method of processing workpieces through dual processing chambers, including a first chamber and a second chamber, comprising, in sequence, the steps of:
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(a) switching a common remote plasma source to the first chamber ON and to the second chamber OFF, (b) etching a workpiece in the first chamber while simultaneously removing an etched workpiece from the second chamber and reloading the second chamber with another workpiece to be etched, (c) switching the common remote plasma source to the first chamber OFF and to the second chamber ON, (d) etching the workpiece in the second chamber while simultaneously removing the etched workpiece from the first chamber and reloading the first chamber with yet another workpiece to be etched, and (e) continuously repeating steps (a)-(d). - View Dependent Claims (11)
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12. A method of continuously processing a plurality of workpieces comprising, in sequence, the steps of:
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(a) supplying products of a remote plasma, generated by a common source of radio frequency power, exclusively to one of a pair of processing chambers, (b) plasma treating a first workpiece in a deep vacuum solely in the one processing chamber while simultaneously executing at substantially atmospheric pressure substantially all pre-processing overhead tasks relative to plasma treating a second workpiece in the other processing chamber, (c) supplying products of a remote plasma, generated by the common source of radio frequency power, exclusively to the other processing chamber and plasma treating the second workpiece in a deep vacuum solely therein while simultaneously executing at substantially atmospheric pressure substantially all post-processing overhead tasks relative to the first workpiece removed from and substantially all pre-processing overhead tasks relative to a third workpiece placed in the one processing chamber, (d) supplying products of a remote plasma generated by the common source of radio frequency power to the one processing chamber and plasma treating the third workpiece in a deep vacuum solely therein while simultaneously executing at substantially atmospheric pressure substantially all post-processing overhead tasks relative to the second workpiece and substantially all preprocessing overhead tasks relative to a fourth workpiece placed in the other processing chamber, and (e) continuously repeating steps (c) and (d) in sequence substituting therein the appropriate odd and even numbered succeeding workpiece in sequence. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
placing the processing chambers adjacent to each other.
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14. The method of claim 12 wherein the step of supplying radio frequency power further comprises the step of:
supplying microwave power.
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15. The method of claim 12 the step of plasma treating solely in one chamber at a time further comprises the step of:
plasma treating one workpiece in one processing chambers without overlapping the plasma treating of another workpiece in the other chamber.
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16. The method of claim 12 further comprising the steps of:
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wherein the step of plasma treating solely in one chamber at a time includes beginning the plasma treating step with closing the door of the chamber with the workpiece to be processed next inside and ending that step with the opening of the door of that chamber at the completion of the processing of that workpiece, and wherein the step of while simultaneously executing all of the overhead tasks includes a robot starting and completing all of said tasks between the beginning and ending of the plasma treating step.
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17. The method of claim 12 wherein the plurality of processing chambers is two.
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18. The method of claim 12 wherein the plasma treating while simultaneously executing steps further comprise the steps of:
alternately and synchronously finishing plasma treating a wafer in a chamber just as a robot finishes removing a fresh wafer from a cassette adjacent that chamber with its one gripper ready for an exchange with its other gripper, wherein the chamber overhead is shorter than the plasma treating time.
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19. The method of claim 18 wherein the plasma treating while simultaneously executing steps further comprise the steps of:
making the robot wait time substantially zero.
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20. The method of claim 18 wherein the plasma treating while simultaneously executing steps further comprise the steps of:
making the robot wait time near zero.
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21. The method of claim 20 wherein the step of making the robot wait time near zero further comprises the step of:
shortening and equalizing the processing times in the adjacent chambers while speeding up the robot to finish his tasks in the same or similar amount of time.
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22. The method of claim 18 wherein the plasma treating while simultaneously executing steps further comprise the steps of:
alternately and synchronously removing and returning workpieces from two cassettes whereby all of the workpieces are removed from one cassette before plasma treating, but, are returned to the other cassette after plasma treating.
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23. The method of claim 12 wherein the plasma treating while simultaneously executing steps further comprise the steps of:
alternately and synchronously removing and returning workpieces from two cassettes whereby all of the workpieces are removed from one cassette before plasma treating and are returned to their original slot in the same cassette after plasma treating before any workpieces in the other cassette begin plasma treating.
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24. The method of claim 12 wherein the plasma treating while simultaneously executing steps further comprise the steps of:
alternately and synchronously removing and returning workpieces from one cassette whereby all of the odd numbered workpieces are plasma treated in one chamber and all of the even numbered workpieces are plasma treated in the other chamber, but all workpieces are returned to their original slots in the single cassette.
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25. The method of claim 12 further comprising the steps of:
operating a dedicated chamber pump-down vacuum pump while bypassing a throttle valve during chamber pump-down, and operating a dedicated chamber process gas vacuum pump coupled to the throttle valve during plasma treatment of a wafer for stabilizing a chamber operating pressure.
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26. The method of claim 12 further comprising the steps of:
venting one chamber to atmosphere without disturbing the process gas flow in the other chamber.
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27. The method of claim 26 further comprising the steps of:
initially slow venting the one chamber immediately followed by fast venting that chamber.
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28. The method of claim 27
wherein the initially slow venting step further comprises the step of opening a small orifice valve, and wherein the fast venting step further comprises the steps of shutting the open small orifice valve, opening a large orifice valve, and backfilling the chamber with a gas from a pressurized back-fill tank. -
29. The method of claim 12 further comprising the step of:
trickle purging for preventing air and moisture from entering a chamber while the chamber is vented to atmosphere by providing a gas to the chamber.
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30. The method of claim 12 further comprising the steps of:
interaction preventing for isolating one chamber from the other when connecting both chambers to a single vacuum pump by providing a vacuum reservoir equivalent.
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31. The method of claim 30 wherein the step of interaction preventing by providing a vacuum reservoir equivalent further comprising the step of:
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 plasma treating the wafer.
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32. The method of claim 31 wherein the step of interaction preventing by providing a vacuum reservoir equivalent further comprises the step of:
making the vacuum lines long enough and big enough in diameter so that the air burst pressure will 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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33. The method of claim 31 wherein the step of interaction preventing by providing a vacuum reservoir equivalent further comprising the step of:
slowing the initial burst of air from the chamber being pumped down by passing the air burst through a small orifice valve followed, a second or two later, by passing the air burst through a large orifice valve providing a higher conductance to rapidly pump the remaining air from the chamber.
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34. The method of claim 12 further comprising the steps of:
receiving light for detecting the end point of the plasma treatment by transmitting light emmissions from each chamber through a fiber optic line to a monochromator.
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35. The method of claim 34 herein the steps of receiving light for detecting the end point of the plasma treatment by transmitting light emissions further comprises the steps of:
passing the light emissions from each chamber only while a respective one of the chambers is plasma treating through a switchless optical junction where the signals from the two chambers are summed.
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36. The method of claim 12 wherein each workpiece is a cassette containing multiple substrates all of which are plasma etched simultaneously as one batch.
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37. The method of claims 12 wherein each workpiece is a substrate.
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38. The method of claim 12, wherein plasma treating comprises etching.
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39. The method of claim 38, herein etching comprises photoresist ashing.
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40. A continuous method of processing workpieces with a remote plasma generator having a single power supply and dual chambers of a second stage processor comprising, in sequence, the steps of:
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(a) directing the output of the remote plasma generator only into a first path and closing a second path, (b) plasma etching a first workpiece in the first chamber to completion while simultaneously removing an etched workpiece from the second chamber and reloading the second chamber with a second workpiece to be etched, (c) opening the second path and directing the output of the remote plasma generator only into the second path and closing the first path, (d) plasma etching the second workpiece in the second chamber to completion using the output of the remote plasma generator while simultaneously removing the etched first workpiece from the first chamber and reloading the first chamber with a third workpiece to be etched, and (e) continuously repeating steps (a)-(d). - View Dependent Claims (41, 42, 43, 44, 45)
preserving the vacuum in the chamber which is plasma etching by closing a valve in the path to the other chamber.
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45. The method of claim 40 wherein the remote plasma generator comprises a single power source, a power splitter and a pair of remote plasma applicators.
Specification