MULTI-EXPOSURE LITHOGRAPHY EMPLOYING DIFFERENTIALLY SENSITIVE PHOTORESIST LAYERS
First Claim
1. A method of forming a patterned structure comprising:
- forming a stack of, from bottom to top, a second photoresist and a first photoresist on a substrate;
lithographically patterning said first photoresist with a first pattern, wherein a top surface of said second photoresist is exposed in an area of said first pattern; and
lithographically forming a second pattern in said second photoresist, wherein said second pattern includes a plurality of line troughs, wherein each of said plurality of line troughs includes a narrow portion having a first width, and wherein at least one of said plurality of line troughs includes a bulge portion having a second width greater than said first width, wherein said bulge portion is formed underneath said area of said first pattern.
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Accused Products
Abstract
A stack of a second photoresist having a second photosensitivity and a first photoresist having a first photosensitivity, which is greater than second photosensitivity, is formed on a substrate. A first pattern is formed in the first photoresist by a first exposure and a first development, while the second photoresist underneath remains intact. A second pattern comprising an array of lines is formed in the second photoresist. An exposed portion of the second photoresist underneath a remaining portion of the first photoresist forms a narrow portion of a line pattern, while an exposed portion of the second photoresist outside the area of the remaining portions of the photoresist forms a wide portion of the line pattern. Each wide portion of the line pattern forms a bulge in the second pattern, which increases overlay tolerance between the second pattern and the pattern of conductive vias.
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Citations
25 Claims
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1. A method of forming a patterned structure comprising:
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forming a stack of, from bottom to top, a second photoresist and a first photoresist on a substrate; lithographically patterning said first photoresist with a first pattern, wherein a top surface of said second photoresist is exposed in an area of said first pattern; and lithographically forming a second pattern in said second photoresist, wherein said second pattern includes a plurality of line troughs, wherein each of said plurality of line troughs includes a narrow portion having a first width, and wherein at least one of said plurality of line troughs includes a bulge portion having a second width greater than said first width, wherein said bulge portion is formed underneath said area of said first pattern. - 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 patterned structure comprising:
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at least one exposed second photoresist portion located on a substrate and laterally abutted by at least one second photoresist portion, wherein said at least one second photoresist portion comprises a second unexposed photosensitive material and said at least one exposed second photoresist portion comprises a second exposed photosensitive material, wherein said second exposed photoresist material is a material derived from said second unexposed photoresist material by lithographic exposure; and at least one exposed first photoresist portion located directly on said at least one exposed second photoresist portion and said at least one second photoresist portion and comprising a first exposed photosensitive material. - View Dependent Claims (20, 21, 22, 23, 24, 25)
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Specification