Methods of Forming Etch Masks for Sub-Resolution Substrate Patterning
First Claim
1. A method of patterning a substrate, the method comprising:
- providing a substrate having mandrels positioned on an underlying layer, the mandrels comprised of a first material;
forming first sidewall spacers on exposed sidewalls of the mandrels, the first sidewall spacers comprised of a second material;
forming second sidewall spacers on exposed sidewalls of the first sidewall spacers, the second sidewall spacers comprised of a third material;
forming fill structures that fill open spaces defined between exposed sidewalls of the second sidewall spacers that face each other, the fill structures comprised of a fourth material, wherein top surfaces of the mandrels, the first sidewall spacers, the second sidewall spacers, and the fill structures are all uncovered, and wherein the first material, the second material, the third material and the fourth material are all chemically different from each other.
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Abstract
Techniques disclosed herein provide a method for pitch reduction (increasing pitch/feature density) for creating high-resolution features and also for cutting on pitch of sub-resolution features. Techniques include using multiple materials having different etch characteristics to selectively etch features and create cuts where specified. A sequence of materials or repeating pattern of lines of materials is used that provides selective self-alignment based on different etch resistivities. Combined with an underlying transfer or memorization layer, multiple different etch selectivities can be accessed. An etch mask defines which regions of the lines of multiple materials can be etched.
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Citations
20 Claims
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1. A method of patterning a substrate, the method comprising:
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providing a substrate having mandrels positioned on an underlying layer, the mandrels comprised of a first material; forming first sidewall spacers on exposed sidewalls of the mandrels, the first sidewall spacers comprised of a second material; forming second sidewall spacers on exposed sidewalls of the first sidewall spacers, the second sidewall spacers comprised of a third material; forming fill structures that fill open spaces defined between exposed sidewalls of the second sidewall spacers that face each other, the fill structures comprised of a fourth material, wherein top surfaces of the mandrels, the first sidewall spacers, the second sidewall spacers, and the fill structures are all uncovered, and wherein the first material, the second material, the third material and the fourth material are all chemically different from each other. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of patterning a substrate, the method comprising:
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providing a substrate having mandrels positioned on an underlying layer, the mandrels comprised of a first material; forming first sidewall spacers on exposed sidewalls of the mandrels, the first sidewall spacers comprised of a second material; forming second sidewall spacers on exposed sidewalls of the first sidewall spacers, the second sidewall spacers comprised of a third material; forming fill structures that fill open spaces defined between exposed sidewalls of the second sidewall spacers that face each other, the fill structures comprised of a fourth material, wherein top surfaces of the mandrels, the first sidewall spacers, the second sidewall spacers, and the fill structures are all uncovered, and wherein at least two materials of the first material, the second material, the third material and the fourth material are chemically different from remaining materials.
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20. A patterned structure on a semiconductor substrate, the patterned structure comprising:
a nanofabricated structure on a substrate having lines of four different materials, the lines of four different materials defining a repeating sequence of A-B-C-D-C-B-A in at least a portion of the substrate, a top surface of each line being uncovered, at least two of the lines of four different materials having been created as sidewall spacers using conformal deposition followed by directional etching, wherein lines of respective materials have a half-pitch spacing of less than 16 nanometers, and wherein the lines four different materials are chemically different from each other in that one or more materials can be selectively etched with respect to remaining materials.
Specification