Etching of high aspect ratio structures
First Claim
1. A method of forming an aperture in a silicon oxide layer, the method comprising:
- generating a plasma containing fluorine and at least one element selected from the group consisting of bromine and iodine;
accelerating ions from the plasma toward a surface of the silicon oxide layer;
etching an exposed portion of the silicon oxide layer, thereby advancing an etch front into the silicon oxide layer and forming the aperture having sidewalls;
absorbing components containing the at least one element on the sidewalls of the aperture; and
continuing to advance the etch front and absorb components containing the at least one element on the sidewalls of the aperture until a desired aspect ratio is attained;
wherein the desired aspect ratio is greater than about 5;
1; and
wherein a content of the at least one element is sufficient to produce a taper angle of the sidewalls of greater than about 87°
at the desired aspect ratio.
6 Assignments
0 Petitions
Accused Products
Abstract
Plasma etching processes using a plasma containing fluorine as well as bromine and/or iodine are suited for high aspect ratio etching of trenches, contact holes or other apertures in silicon oxide materials. The plasma is produced using at least one fluorine-containing source gas and at least one bromine- or iodine-containing source gas. Bromine/iodine components of the plasma protect the aperture sidewalls from lateral attack by free fluorine, thus advantageously reducing a tendency for bowing of the sidewalls. Ion bombardment suppresses absorption of bromine/iodine components on the etch front, thus facilitating advancement of the etch front without significantly impacting taper.
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Citations
56 Claims
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1. A method of forming an aperture in a silicon oxide layer, the method comprising:
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generating a plasma containing fluorine and at least one element selected from the group consisting of bromine and iodine;
accelerating ions from the plasma toward a surface of the silicon oxide layer;
etching an exposed portion of the silicon oxide layer, thereby advancing an etch front intothe silicon oxide layer and forming the aperture having sidewalls;
absorbing components containing the at least one element on the sidewalls of the aperture; and
continuing to advance the etch front and absorb components containing the at least one element on the sidewalls of the aperture until a desired aspect ratio is attained;
wherein the desired aspect ratio is greater than about 5;
1; and
wherein a content of the at least one element is sufficient to produce a taper angle of the sidewalls of greater than about 87°
at the desired aspect ratio. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of forming an aperture in a silicon oxide layer, the method comprising:
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generating a plasma containing fluorine and bromine;
accelerating ions from the plasma toward a surface of the silicon oxide layer;
etching an exposed portion of the silicon oxide layer, thereby exposing sidewalls of the silicon oxide layer;
absorbing components containing bromine on the sidewalls of the silicon oxide layer; and
continuing to etch the exposed portion of the silicon oxide layer and to absorb components containing bromine on the sidewalls of the silicon oxide layer until an aperture having a desired aspect ratio is attained;
wherein the desired aspect ratio is greater than about 5;
1; and
wherein a content of the bromine in the plasma is sufficient to produce a taper angle of the sidewalls of greater than about 87°
at the desired aspect ratio. - View Dependent Claims (18)
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19. A method of forming an aperture in a silicon oxide layer, the method comprising:
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generating a plasma containing fluorine and iodine;
accelerating ions from the plasma toward a surface of the silicon oxide layer;
etching an exposed portion of the silicon oxide layer, thereby exposing sidewalls of the silicon oxide layer;
absorbing components containing iodine on the sidewalls of the silicon oxide layer; and
continuing to etch the exposed portion of the silicon oxide layer and to absorb components containing iodine on the sidewalls of the silicon oxide layer until an aperture having a desired aspect ratio is attained;
wherein a content of the iodine in the plasma is sufficient to produce a taper angle of the sidewalls of greater than about 87°
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20. A method of forming an aperture in a silicon oxide layer, the method comprising:
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generating a plasma comprising at least one first source gas and at least one second source gas, wherein each at least one first source gas is a fluorocarbon gas and each at least one second source gas is selected from the group consisting of a bromine-containing gas and an iodine-containing gas;
accelerating ions from the plasma perpendicularly toward a surface of the silicon oxide layer;
advancing an etch front in the silicon oxide layer, thereby exposing sidewalls of the silicon oxide layer;
absorbing components from the plasma on the sidewalls of the silicon oxide layer, wherein the absorbed components are selected from the group consisting of bromine-containing components and iodine-containing components and wherein the absorbed components are sufficient to passivate the sidewalls of the silicon oxide layer from attack by fluorine-containing components of the plasma; and
continuing to advance the etch front until a desired aspect ratio is attained, wherein the desired aspect ratio is greater than about 8;
1. - View Dependent Claims (21, 22, 23, 24)
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25. A method of forming an aperture in a silicon oxide layer, the method comprising:
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generating a plasma comprising at least one fluorocarbon gas and at least one bromine-containing gas;
accelerating ions from the plasma perpendicularly toward a surface of the silicon oxide layer;
advancing an etch front in the silicon oxide layer, thereby exposing sidewalls of the silicon oxide layer;
absorbing bromine-containing components from the plasma on the sidewalls of the silicon oxide layer, wherein the absorbed bromine-containing components are sufficient to passivate the sidewalls of the silicon oxide layer from attack by fluorine-containing components of the plasma; and
continuing to advance the etch front until a desired aspect ratio is attained, wherein the desired aspect ratio is greater than about 8;
1. - View Dependent Claims (26, 27)
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28. A method of forming an aperture in a silicon oxide layer, the method comprising:
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generating a plasma comprising at least one fluorocarbon gas and at least one iodine-containing gas;
accelerating ions from the plasma perpendicularly toward a surface of the silicon oxide layer;
advancing an etch front in the silicon oxide layer, thereby exposing sidewalls of the silicon oxide layer;
absorbing iodine-containing components from the plasma on the sidewalls of the silicon oxide layer, wherein the absorbed iodine-containing components are sufficient to passivate the sidewalls of the silicon oxide layer from attack by fluorine-containing components of the plasma; and
continuing to advance the etch front until a desired aspect ratio is attained, wherein the desired aspect ratio is greater than about 8;
1.
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29. A method of forming an aperture in a silicon oxide layer, the method comprising:
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generating a plasma comprising at least one first source gas and at least one second source gas, wherein each at least one first source gas is a fluorocarbon gas and each at least one second source gas contains an element selected from the group consisting of bromine and iodine;
accelerating ions from the plasma perpendicularly toward a surface of the silicon oxide layer;
advancing an etch front in the silicon oxide layer, thereby exposing sidewalls of the silicon oxide layer;
forming a polymer residue on the sidewalls of the silicon oxide layer;
passivating the polymer residue on the sidewalls of the silicon oxide layer through reaction with components of the at least one second source gas; and
continuing to advance the etch front until a desired aspect ratio is attained, wherein the desired aspect ratio is greater than about 5;
1. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36)
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37. A method of forming an aperture in a silicon oxide layer, the method comprising:
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generating a plasma comprising at least one first source gas and at least one second source gas, wherein each at least one first source gas is a fluorocarbon gas and each at least one second source gas is a bromine-containing gas;
accelerating ions from the plasma perpendicularly toward a surface of the silicon oxide layer;
advancing an etch front in the silicon oxide layer, thereby exposing sidewalls of the silicon oxide layer;
forming a polymer residue on the sidewalls of the silicon oxide layer;
brominating the polymer residue on the sidewalls of the silicon oxide layer, thereby passivating the polymer residue from attack by fluorine-containing components of the plasma; and
continuing to advance the etch front until a desired aspect ratio is attained, wherein the desired aspect ratio is greater than about 5;
1. - View Dependent Claims (38)
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39. A method of forming an aperture in a silicon oxide layer, the method comprising:
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generating a plasma comprising at least one first source gas and at least one second source gas, wherein each at least one first source gas is a fluorocarbon gas and each at least one second source gas is an iodine-containing gas;
accelerating ions from the plasma perpendicularly toward a surface of the silicon oxide layer;
advancing an etch front in the silicon oxide layer, thereby exposing sidewalls of the silicon oxide layer;
forming a polymer residue on the sidewalls of the silicon oxide layer;
iodizing the polymer residue on the sidewalls of the silicon oxide layer, thereby passivating the polymer residue from attack by fluorine-containing components of the plasma; and
continuing to advance the etch front until a desired aspect ratio is attained, wherein the desired aspect ratio is greater than about 5;
1. - View Dependent Claims (40)
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41. A method of forming an aperture in a silicon oxide layer, the method comprising:
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generating a plasma comprising at least one first source gas, wherein each at least one first source gas is a fluorocarbon gas;
accelerating ions from the plasma perpendicularly toward a surface of the silicon oxide layer;
advancing an etch front in the silicon oxide layer, thereby exposing sidewalls of the silicon oxide layer;
forming a polymer residue on the sidewalls of the silicon oxide layer;
after forming the polymer residue on the sidewalls of the silicon oxide layer, adding at least one second source gas to the plasma while continuing to advance the etch front, wherein each at least one second source gas contains an element selected from the group consisting of bromine and iodine;
passivating the polymer residue on the sidewalls of the silicon oxide layer through reaction with components of the at least one second source gas; and
continuing to advance the etch front until a desired aspect ratio is attained. - View Dependent Claims (42, 43, 44, 45, 46, 47, 48)
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49. A method of forming an aperture in a silicon oxide layer, the method comprising:
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generating a plasma comprising at least one first source gas, wherein each at least one first source gas is a fluorocarbon gas;
accelerating ions from the plasma perpendicularly toward a surface of the silicon oxide layer;
advancing an etch front in the silicon oxide layer, thereby exposing sidewalls of the silicon oxide layer;
forming a polymer residue on the sidewalls of the silicon oxide layer;
after forming a polymer residue on the sidewalls of the silicon oxide layer, adding at least one second source gas to the plasma while continuing to advance the etch front, wherein each at least one second source gas is a bromine-containing gas;
brominating the polymer residue on the sidewalls of the silicon oxide layer, thereby passivating the polymer residue from attack by fluorine-containing components of the plasma; and
continuing to advance the etch front until a desired aspect ratio is attained. - View Dependent Claims (50, 51, 52)
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53. A method of forming an aperture in a silicon oxide layer, the method comprising:
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generating a plasma comprising at least one first source gas, wherein each at least one first source gas is a fluorocarbon gas;
accelerating ions from the plasma perpendicularly toward a surface of the silicon oxide layer;
advancing an etch front in the silicon oxide layer, thereby exposing sidewalls of the silicon oxide layer;
forming a polymer residue on the sidewalls of the silicon oxide layer;
after forming a polymer residue on the sidewalls of the silicon oxide layer, adding at least one second source gas to the plasma while continuing to advance the etch front, wherein each at least one second source gas is an iodine-containing gas;
iodizing the polymer residue on the sidewalls of the silicon oxide layer, thereby passivating the polymer residue from attack by fluorine-containing components of the plasma; and
continuing to advance the etch front until a desired aspect ratio is attained. - View Dependent Claims (54, 55, 56)
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Specification