Via-first self-aligned interconnect formation process
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsYu-Tse Lai, Ya Hui Chang
Life of this patent
Estimating the term…
Abstract
A structure includes a dielectric layer, and a metal line in the dielectric layer. The metal line has a first straight edge and a second straight edge extending in a lengthwise direction of the metal line. The first straight edge and the second straight edge are parallel to each other. A via is underlying and joined to the metal line. The via has a third straight edge underlying and vertically aligned to the first straight edge, and a first curved edge and a second curved edge connecting to opposite ends of the third straight edge.
Claims20
A method comprising:
- forming a dielectric layer over a substrate;
- forming a first hard mask over the dielectric layer;
- forming a second hard mask over the first hard mask;
- etching the second hard mask to form a first opening in the second hard mask, wherein the first opening has a first width;
- forming a third hard mask over the second hard mask and filling the first opening;
- etching the third hard mask and the first hard mask to form a trench in the third hard mask and a second opening in the first hard mask, wherein the trench comprises a portion directly above the first opening, wherein the first opening is directly above the second opening, and wherein the trench has a second width that is less than the first width of the first opening, and the second opening has a third width that is smaller than or equal to the second width of the trench;
- performing a first etching process on the dielectric layer to extend the trench and the second opening into the dielectric layer;
- and
- forming a metal line and a via in the trench and the second opening, respectively.
A method comprising:
- etching a dielectric layer to form:
- a trench, wherein the dielectric layer comprises a first edge and a second edge facing the trench and parallel to a lengthwise direction of the trench;
- and
- a via opening underlying and connected to the trench, wherein the dielectric layer further comprises:
- a third edge and a fourth edge facing the via opening, wherein the third edge and the fourth edge are vertically aligned to the first edge and the second edge, respectively;
- and
- a first curved edge connecting the third edge to the fourth edge;
- and
- filling the trench and the via opening to form a metal line and a via, respectively.
A method comprising:
- forming a first metal line comprising a first straight edge parallel to a lengthwise direction of the first metal line;
- and
- forming a first via overlapped by the first metal line, wherein an entirety of the first via is directly underlying the first metal line, and the first via comprises:
- a first curved edge overlapped by the first metal line;
- and
- a second straight edge vertically aligned to the first straight edge of the first metal line, wherein the second straight edge is joined to the first curved edge.
Dependencies are inferred from the claim text.