Method and apparatus for micromachining using a magnetic field and plasma etching
First Claim
1. A method of forming a microstructure by micromachining, comprising:
- providing a substrate in a processing chamber, said substrate comprising an etchable material and having at least one contoured feature;
generating a stable ion-containing etching plasma in said processing chamber, said plasma etching the contoured feature of said substrate;
generating a magnetic field, said magnetic field being adjustable in intensity and direction;
applying an RF bias power to said substrate, said RF bias power being adjustable in intensity; and
controlling said etching of the contoured feature by creating an electron differential at said contoured feature by adjusting at least one of said magnetic field intensity, magnetic field direction, and RF bias power intensity during said etching, thereby forming a second contoured feature at said contoured feature.
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Abstract
This invention relates to a method and apparatus for forming a micromachined device, where a workpiece is plasma etched to define a microstructure. The plasma etching is conducted in the presence of a magnetic field, which can be generated and manipulated by an electric field. The magnetic field effects the electrons present in the plasma by directing them to “collect” on a desired plane or surface of the workpiece. The electrons attract the ions of the plasma to etch the desired region of the a workpiece to a greater extent than other regions of the workpiece, thereby enabling the formation of more precise “cuts” in the workpiece to form specific shapes of microstructures. The magnetic field can be controlled in direction and intensity and substrate bias power can also be controlled during etching to precisely and accurately etch the workpiece.
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Citations
66 Claims
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1. A method of forming a microstructure by micromachining, comprising:
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providing a substrate in a processing chamber, said substrate comprising an etchable material and having at least one contoured feature;
generating a stable ion-containing etching plasma in said processing chamber, said plasma etching the contoured feature of said substrate;
generating a magnetic field, said magnetic field being adjustable in intensity and direction;
applying an RF bias power to said substrate, said RF bias power being adjustable in intensity; and
controlling said etching of the contoured feature by creating an electron differential at said contoured feature by adjusting at least one of said magnetic field intensity, magnetic field direction, and RF bias power intensity during said etching, thereby forming a second contoured feature at said contoured feature. - 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)
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28. A method of forming a fabricated device, comprising:
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providing a contoured workpiece;
generating a stable plasma, said plasma comprising free electrons and ions, said free electrons having a velocity toward said workpiece;
generating a magnetic field at said workpiece and within said plasma;
forming a high negative charge density region on a contoured region of said workpiece by effecting the path of travel of said free electrons with said magnetic field, thereby forming a contoured feature at said contoured region; and
changing the location of said high negative charge density region by changing a direction of said magnetic field while etching said workpiece with said plasma. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52)
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53. A method of plasma etching a material layer to form a microstructure, comprising:
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providing a material layer having at least one contour;
flowing gas into a chamber containing said material layer;
generating a stable etching plasma from said gas, wherein said plasma comprises free electrons and ions generating a magnetic field, said magnetic field being adjustable in intensity and direction;
asymmetrically etching said material layer at said at least one contour with said plasma to form a second contour at said at least one contour; and
varying the location of said etching during said etching by varying a location of impingement of said free electrons on said material layer. - View Dependent Claims (54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65)
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66. A method of forming a plasma etched device, comprising:
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providing a contoured workpiece comprising an insulating material in a plasma chamber;
generating a stable plasma within said chamber from a gas flow, said plasma comprising free electrons and ions, said free electrons having a path of travel toward said workpiece, said ions etching said workpiece, thereby forming a contoured feature at a contour of said workpiece;
generating a magnetic field at said workpiece and controlling said magnetic field in intensity and direction to vary a location of impingement of said free electrons on said workpiece, said location of impingement of said ions on said workpiece being effected by the location of impingement of free electrons on said workpiece; and
applying an RF bias power to said workpiece during ion etching and adjusting said RF bias power during etching to vary the intensity of etching.
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Specification