Claims
- 1. A method of forming a field emission cathode structure of a field emission device, said method comprising:patterning a first layer to form a patterned first layer, said first layer being disposed upon a second layer, said second layer being disposed upon a third layer; patterning said second layer to form a patterned second layer that is determined by said patterned first layer; and removing a portion of said third layer such that said patterned first layer is partially mobilized and said patterned second layer is substantially not mobilized, wherein said third layer is removed by undercutting beneath said patterned second layer, and wherein said third layer forms a conical structure having a tapered, substantially rectilinear removal profile beneath said patterned second layer.
- 2. A method according to claim 1, wherein said first layer comprises a photoresist.
- 3. A method according to claim 1, wherein said second layer comprises silicon dioxide.
- 4. A method according to claim 1, wherein said second layer comprises silicon dioxide and is formed by thermal conversion of said third layer.
- 5. A method according to claim 1, wherein said second layer comprises silicon dioxide, said second layer being formed by chemical vapor deposition upon said third layer.
- 6. A method according to claim 1, wherein said third layer comprises silicon.
- 7. A method according to claim 1, wherein said silicon of said third layer is doped with at least one of phosphorus and boron.
- 8. A method according to claim 1, wherein said tapered, substantially rectilinear removal profile terminates at a top point and terminates at an opposite bottom point at said second layer, wherein a line between said top point and bottom point has an angle that deviates from an axis perpendicular to the plane of said first layer, said second layer, and said third layer in a range from about 20 degrees to about 60 degrees.
- 9. A method according to claim 8, wherein said angle deviates from said axis in a range from about 25 degrees to about 40 degrees.
- 10. A method according to claim 8, wherein said angle deviates from said axis by about 25 degrees to about 30 degrees.
- 11. A method of forming a field emission cathode structure of a field emission device, said method comprising:patterning a first layer to form a patterned first layer, said first layer being disposed upon a second layer, said second layer being disposed upon a third layer; patterning said second layer to form a patterned second layer, whereby said patterned first layer determines said patterned second layer; removing a first portion of said third layer with a first removal chemistry, said first removal chemistry having both anisotropic and isotropic removal properties, whereby a first vertical removal depth comprises about one part in three; and removing a second portion of said third layer with a second removal chemistry, said second removal chemistry having substantially anisotropic removal properties, wherein a second vertical removal depth comprises about two parts in three, wherein said patterned first layer is partially mobilized and said patterned second layer is substantially not mobilized, wherein said third layer is removed by undercutting beneath said patterned second layer, and wherein said third layer has a conical structure and forms a tapered, substantially rectilinear removal profile beneath said patterned second layer.
- 12. A method of forming a field emission cathode structure of a field emission device, said method comprising:forming a substrate; forming a cathode conductive layer upon said substrate; forming a third layer positioned over said cathode conductive layer; forming a second layer disposed upon said third layer; patterning a first layer to form a patterned first layer, said first layer being disposed upon said second layer; patterning said second layer to form a patterned second layer, whereby said patterned first layer determines said patterned second layer; and removing a portion of said third layer, wherein said patterned first layer is partially mobilized and said patterned second layer is substantially not mobilized, wherein said third layer is removed by undercutting beneath said patterned second layer, and wherein said third layer has a conical structure and forms a tapered, substantially rectilinear removal profile beneath said patterned second layer.
- 13. A method according to claim 12, further comprising, after removing said portion of said third layer:forming a conductive gate structure over said cathode conductive layer, said conductive gate structure being separated from said cathode conductive layer by a dielectric layer; and forming an aperture in said conductive gate structure, said conical structure being exposed through said aperture.
- 14. A method according to claim 13, further comprising providing an anode panel separated from said conductive gate structure and said conical structure by a substantial vacuum, said anode panel including a phospholuminescent material.
- 15. A method of forming a field emission cathode structure of a field emission device, said method comprising:forming a substrate; forming a cathode conductive layer upon said substrate; forming a third layer positioned over said cathode conductive layer; forming a second layer disposed upon said third layer; patterning a first layer to form a patterned first layer, said first layer being disposed upon said second layer; patterning said second layer to form a patterned second layer, whereby said patterned first layer determines said patterned second layer; removing a first portion of said third layer with a first removal chemistry, said first removal chemistry having both anisotropic and isotropic removal properties, wherein a first vertical removal depth comprises about one part in three; and removing a second portion of said third layer with a second removal chemistry, said second removal chemistry having substantially anisotropic removal properties, wherein: a second vertical removal depth comprises about two parts in three; said patterned first layer is partially mobilized and said patterned second layer is substantially not mobilized; said second portion of said third layer is removed by undercutting beneath said patterned second layer; and said third layer has a conical structure having a tapered, substantially rectilinear removal profile beneath said patterned second layer.
- 16. A method according to claim 15, further comprising, after removing said second portion of said third layer:forming a dielectric layer over said cathode conductive layer; forming a conductive gate structure over said dielectric layer; and forming an aperture through both of said dielectric layer and said conductive gate structure, said conical structure being exposed through said aperture.
- 17. A method of forming a field emission device comprising:patterning a mask, said mask being disposed upon a blanket oxide, said blanket oxide being disposed upon an emitter layer; and patterning said blanket oxide, whereby said mask determines patterning said blanket oxide; removing a portion of said emitter layer, wherein: said mask is partially mobilized; said portion of said emitter layer is removed by undercutting beneath said blanket oxide; and said partially mobilized mask diminishes etching by secondary collisions.
- 18. A method of forming a field emission device according to claim 17, wherein said mask comprises a positive photoresist of a novalac resin and a photosensitizer.
- 19. A method of forming a field emission device according to claim 17, wherein emitter layer is a semiconductive material.
- 20. A method of forming a field emission device according to claim 17, wherein said emitter layer comprises silicon that is doped with at least one of phosphorus and boron.
- 21. A method of forming a field emission device according to claim 17, wherein removing said portion of said emitter layer is conducted such that a conical structure having a tapered, substantially rectilinear removal profile is formed from said emitter layer in a position below said blanket oxide.
- 22. A method of forming a field emission device comprising:patterning a mask, said mask being disposed upon a blanket oxide, said blanket oxide being disposed upon an emitter layer; patterning said blanket oxide, whereby said mask determines patterning said blanket oxide; removing a first portion of said emitter layer under simultaneous anisotropic and isotropic removal conditions; and removing a second portion of said emitter layer under substantially anisotropic removal conditions, wherein said mask is partially mobilized, said second portion of said emitter layer is removed by undercutting beneath said blanket oxide, and said partially mobilized mask diminishes etching by secondary collisions.
- 23. A method of forming a flat panel display, comprising:providing a substrate; forming an emitter layer over said substrate; forming a blanket oxide layer over said emitter layer; forming a masking layer over said blanket oxide layer; and forming an array of emitter tips from said emitter layer, including: patterning said masking layer to form therefrom an array of discrete masking islands; patterning said blanket oxide layer to form therefrom an array of discrete oxide islands, each of said oxide islands being vertically aligned with one of said masking islands; and removing a portion of said emitter layer, wherein each of said discrete masking islands is partially mobilized and said oxide islands are substantially not mobilized, said portion of said emitter layer being removed by undercutting beneath said oxide islands, thereby forming said array of said emitter tips, each of said emitter tips having a substantially rectilinear vertical profile.
- 24. A method according to claim 23, further comprising, prior to forming said emitter layer, forming a cathode conductive layer over said substrate.
- 25. A method according to claim 24, further comprising, after forming said array of said emitter tips, forming a conductive gate structure over said cathode conductive layer.
- 26. A method according to claim 25, further comprising, after forming said conductive gate structure, disposing an anode panel that includes a phospholuminescent material over said conductive gate structure, said anode panel being separated from said conductive gate structure and from said emitter tips by a substantial vacuum.
- 27. A method according to claim 26, further comprising, after disposing said anode panel, electrically connecting a voltage source with each of said cathode conductive layer, said conductive gate structure, and said anode panel.
RELATED APPLICATIONS
This is a divisional application of U.S. patent application Ser. No. 09/022,763, filed on Feb. 12, 1998, titled “BUFFERED RESIST PROFILE ETCH OF A FIELD EMISSION DEVICE STRUCTURE”, which is incorporated herein by reference.
US Referenced Citations (5)