Plasma assisted chemical transport method and apparatus
First Claim
1. A method for shaping the surface of a workpiece comprising the steps of:
- providing a tool having a working head that has a working head footprint smaller than the area of said workpiece,mounting said working head for motion relative to said workpiece in proximity to and spaced from the surface of said workpiece,energizing said working head to shape a footprint area of the surface of said workpiece that is immediately proximate to said working head,moving said working head relative to said workpiece surface in substantially circular scan paths having a center at a scan center point on said workpiece, andshifting said scan path radially relative to said scan center point to cause said working head footprint to scan over areas of the surface of said workpiece in a plurality of substantially circular scan paths of different radii each having a center at said scan center point, wherein all said radii have finite values, whereby the center of said working head footprint is spaced from said scan center point in all of said scan paths.
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Accused Products
Abstract
A plasma assisted chemical transport system for additive or subtractive shaping of a substrate surface employs a plasma head (30) that generates a plasma (34) and is caused to scan the surface of a workpiece (51) to provide selective shaping, either by etching or depositing material. Corrosive gases of the plasma are isolated to minimize corrosive effects on the drive mechanism (20) by encompassing the plasma head within a flexible bellows (64). Scanning is in a circular path of varying radius. Acceleration induced vibrations caused by programmed varying scan velocity are avoided by use of an oppositely rotation body (56) of equal torsional inertia. Effects of linear acceleration in the radial direction are effectively avoided by making rotational scan velocity many times greater than radial scan velocity. Errors due to singularity that could exist when the scanning plasma head is at the center of its scan are kept within acceptable tolerances by stopping the scan when the center of the scanning head (30) is at a distance Δr from the center of the scan path that is equal to incremental radial steps between successive circular scan paths.
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Citations
38 Claims
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1. A method for shaping the surface of a workpiece comprising the steps of:
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providing a tool having a working head that has a working head footprint smaller than the area of said workpiece, mounting said working head for motion relative to said workpiece in proximity to and spaced from the surface of said workpiece, energizing said working head to shape a footprint area of the surface of said workpiece that is immediately proximate to said working head, moving said working head relative to said workpiece surface in substantially circular scan paths having a center at a scan center point on said workpiece, and shifting said scan path radially relative to said scan center point to cause said working head footprint to scan over areas of the surface of said workpiece in a plurality of substantially circular scan paths of different radii each having a center at said scan center point, wherein all said radii have finite values, whereby the center of said working head footprint is spaced from said scan center point in all of said scan paths. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for scanning a tool head over a workpiece to shape the surface of the workpiece without contact, comprising the steps of:
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moving the tool head in scan step amounts of Δ
r over the workpiece in a plurality of mutually adjacent, substantially circular scan paths of successively changing radii, wherein each of said scan paths is substantially centered on a scan path axis, anddisabling said scanning when the radius of any of said scan paths is less than said scan step amount of Δ
r. - View Dependent Claims (28)
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13. A method for scanning a tool head over a workpiece comprising the steps of:
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moving the tool head in scan step amounts of Δ
r over the workpiece in a plurality of mutually adjacent, substantially circular scan paths of successively changing radii, wherein each of said scan paths is substantially centered on a scan path axis, anddisabling said scanning when the radius of any of said scan paths is less than said scan step amount of Δ
r,wherein said tool head has a tool head area having a tool head radius, and wherein said scan step amount of Δ
r is much smaller than the radius of said tool head radius.
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14. A method for scanning a tool head over a workpiece comprising the steps of:
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moving the tool head in scan step amounts of Δ
r over the workpiece in a plurality of mutually adjacent, substantially circular scan paths of successively changing radii, wherein each of said scan paths is substantially centered on a scan path axis, anddisabling said scanning when the radius of any of said scan paths is less than said scan step amount of Δ
r,wherein said tool head has an area, and wherein said scan step amount of Δ
r is a small fraction of a major dimension of said area.
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15. A method for scanning a tool head over a workpiece comprising the steps of:
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moving the tool head in scan step amounts of Δ
r over the workpiece in a plurality of mutually adjacent, substantially circular scan paths of successively changing radii, wherein each of said scan paths is substantially centered on a scan path axis, anddisabling said scanning when the radius of any of said scan paths is less than said scan step amount of Δ
r,wherein said tool head has a circular footprint, and wherein said scan step amount of Δ
r is a small fraction of the radius of said footprint. - View Dependent Claims (16, 17)
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18. A method for scanning a tool head over a workpiece comprising the steps of:
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moving the tool head in scan step amounts of Δ
r over the workpiece in a plurality of mutually adjacent, substantially circular scan paths of successively changing radii, wherein each of said scan paths is substantially centered on a scan path axis, anddisabling said scanning when the radius of any of said scan paths is less than said scan step amount of Δ
r,wherein said tool head has a circular footprint, and wherein said footprint in each scan overlaps the footprint of a preceding scan. - View Dependent Claims (19, 20, 21)
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22. A method for scanning a tool head over a workpiece comprising the steps of:
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moving the tool head in scan step amounts of Δ
r over the workpiece in a plurality of mutually adjacent, substantially circular scan paths of successively changing radii, wherein each of said scan paths is substantially centered on a scan path axis, anddisabling said scanning when the radius of any of said scan paths is less than said scan step amount of Δ
r,wherein said step of moving said tool head in substantially circular scan paths includes the step of varying the angular velocity of said tool head to thereby introduce acceleration induced rotational vibration, and employing an oppositely rotating torsional body coupled with said tool head for balancing out said rotational vibration. - View Dependent Claims (23, 24, 25, 26, 27)
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29. A method for scanning a tool head over a workpiece comprising the steps of:
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moving the tool head in scan step amounts of Δ
r over the workpiece in a plurality of mutually adjacent, substantially circular scan paths of successively changing radii, wherein each of said scan paths is substantially centered on a scan path axis,disabling said scanning when the radius of any of said scan paths is less than said scan step amount of Δ
r, andincluding the step of causing said tool head to shape the surface of said workpiece by a plasma assisted chemical transport reaction.
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30. A method for scanning a tool head over a workpiece comprising the steps of:
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moving the tool head in scan step amounts of Δ
r over the workpiece in a plurality of mutually adjacent, substantially circular scan paths of successively changing radii, wherein each of said scan paths is substantially centered on a scan path axis, anddisabling said scanning when the radius of any of said scan paths is less than said scan step amount of Δ
r,wherein said step of moving said tool head comprises moving said tool head over said workpiece at a distance from said workpiece and causing said tool head to shape the surface of said workpiece by a plasma assisted chemical vapor transport reaction.
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31. A method for scanning a tool head over a workpiece comprising the steps of:
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moving the tool head in scan step amounts of Δ
r over the workpiece in a plurality of mutually adjacent, substantially circular scan paths of successively changing radii, wherein each of said scan paths is substantially centered on a scan path axis, anddisabling said scanning when the radius of any of said scan paths is less than said scan step amount of Δ
r,wherein said step of moving said tool head comprises the steps of providing a plasma assisted chemical vapor tool head, feeding a reactive gas to said tool head between the tool head and said workpiece, applying a radio frequency voltage across said tool head and workpiece to produce a plasma assisted chemical vapor transport reaction including corrosive gases, employing a mechanical drive mechanism to move said tool head, and positioning a protective curtain between said tool head and said drive mechanism to restrain flow of said reactive gases to said drive mechanism.
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32. A tool comprising:
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a housing, a reaction chamber in said housing for containing a corrosive fluid, a workpiece support mounted in said chamber, a reaction tool mounted to said housing for movement within said reaction chamber and for generating a corrosive fluid within said chamber, wherein said reaction tool comprises a movable platform movably mounted to said housing, and wherein said environmental separator comprises a flexible curtain circumscribing said reaction tool, said curtain having one part fixed and sealed to said movable platform and another part fixed and sealed to said workpiece support, a drive mechanism mounted to the housing externally of said reaction chamber and connected to said reaction tool to drive said reaction tool within said chamber, and a flexible environment separator connected between said housing and said tool and configured and arranged to block passage of said corrosive fluid to said drive mechanism. - View Dependent Claims (33, 34, 35)
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36. A plasma assisted chemical transport system comprising:
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a housing, a reaction chamber in said housing for containing a reactive fluid, an upper platform slidably mounted to said housing for linear movement in a first direction, a reaction tool in said chamber mounted to said platform for motion therewith, a drive mechanism connected to drive said platform and said reaction tool, a workpiece support rotatably mounted to said housing in said chamber adjacent said reaction tool, a drive motor mounted to said housing and connected to rotate said workpiece support, and a flexible environmental separator circumscribing said reaction tool and connected and sealed to and between said upper platform and said housing, said separator being configured, arranged and positioned to block passage of said reactive fluid to said drive mechanism. - View Dependent Claims (37)
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38. A plasma assisted vapor transport tool comprising:
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a base housing section, an intermediate housing section mounted to said base housing section for linear motion in a first direction relative to said base housing section and having a bottom wall, a first drive mechanism on said base housing section connected to drive said intermediate housing section, an upper platform mounted to said intermediate housing section for linear motion in a second direction orthogonal to said first direction, a second drive mechanism mounted to said intermediate section for driving said upper platform, said base section and part of said intermediate housing section forming a first chamber, said intermediate section and said upper platform forming a second chamber, said intermediate section including a bottom wall having an opening therein, a workpiece support mounted to said base housing section and including a workpiece holding chuck positioned adjacent said opening, a plasma reaction tool mounted to said upper platform within said intermediate housing section and within said second chamber, said tool having a tool head adjacent said chuck for generating plasma, a first flexible environmental separator connected between a lower side of said intermediate section bottom wall and said base section and positioned between said chuck and said first drive mechanism and configured and arranged to block passage of said plasma from said plasma reaction tool to said first drive mechanism, a second flexible environmental separator connected between an upper side of said intermediate section bottom wall and a lower side of said upper platform and positioned between said reaction tool and said second drive mechanism and configured and arranged to block passage of corrosive fluid from said plasma reaction tool to said second drive mechanism.
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Specification