Textile patterning for subtractively-patterned self-aligned interconnects, plugs, and vias
View Patent ↗Embodiments of the invention include methods of forming a textile patterned hardmask. In an embodiment, a first hardmask and a second hardmask are formed over a top surface of an interconnect layer in an alternating pattern. A sacrificial cross-grating may then be formed over the first and second hardmasks. In an embodiment, portions of the first hardmask that are not covered by the sacrificial cross-grating are removed to form first openings and a third hardmask is disposed into the first openings. Embodiments may then include etching through portions of the second hardmask that are not covered by the sacrificial cross-grating to form second openings. The second openings may be filled with a fourth hardmask. According to an embodiment, the first, second, third, and fourth hardmasks are etch selective to each other. In an embodiment the sacrificial cross-grating may then be removed.
1. An interconnect structure comprising:
an interlayer dielectric (ILD) material;
a first interconnect line formed adjacent to the ILD material;
one or more vias formed over a top surface of the first interconnect line, wherein a sidewall of the via is aligned with a sidewall of the first interconnect line, and wherein portions of the top surface of the first interconnect line that are not covered by a via are covered by a dielectric fill material;
one or more dielectric lines formed over a top surface of the ILD material, wherein the one or more dielectric lines extend in a direction orthogonal to a direction the first interconnect line extends; and
a second interconnect line coupled to the first interconnect line by one of the one or more vias, the second interconnect line extending in a direction orthogonal to the first interconnect line, and wherein the one or more dielectric lines have a thickness that is less than a thickness of the second interconnect line.
2. The interconnect structure of claim 1 , wherein one of the plurality of dielectric lines passes over a top surface of the dielectric fill material.
3. The interconnect structure of claim 2 , wherein a first dielectric line includes a sidewall that is aligned with a first sidewall of a first via, and wherein a second dielectric line includes a sidewall that is aligned with a second sidewall of the first via that is opposite to the first sidewall of the first via.
4. The interconnect structure of claim 3 , further comprising an extension layer formed over a top surface of the first dielectric line and a top surface of the second dielectric line.
5. The interconnect structure of claim 4 , wherein the extension layer is formed with a directed self-assembly (DSA) process.
6. The interconnect structure of claim 5 , wherein the extension layer is one block of a diblock copolymer.
7. The interconnect structure of claim 3 , wherein the second interconnect line is formed partially above one of the dielectric lines and partially over the first via.
8. The interconnect structure of claim 3 , wherein a first of the dielectric lines is formed over the dielectric fill material, and wherein a second interconnect line is formed partially over the first dielectric line and partially over the ILD material.
9. The interconnect structure of claim 1 , further comprising a dielectric plug adjacent to the first interconnect line, wherein a sidewall of the interconnect line is aligned with a sidewall of the dielectric plug.
10. The interconnect structure of claim 1 , wherein the dielectric fill material is the same material as the ILD material.