Additional etching to increase via contact area
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsPei-Yi Lin, Chung-Ju Lee, Shau-Lin Shue
Life of this patent
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Abstract
An integrated circuit structure includes a dielectric layer, and a conductive line in the dielectric layer. The conductive line has a first top surface and a second top surface lower than the first top surface, and a sidewall connecting the first top surface to the second top surface. A via includes a portion overlying the second top surface of the conductive line. The via is electrically coupled to the conductive line through the second top surface and the sidewall of the conductive line.
Claims24
1-14. (canceled)
A method comprising:
- forming a dielectric layer over a conductive line;
- performing a first etching step to etch the dielectric layer to form an opening, with at least a portion of the opening substantially aligned to the conductive line, wherein the opening generated by the first etching step has a bottom lower than a top surface of the conductive line;
- performing a second etching step to remove a corner portion of the conductive line;
- and
- filling the opening with a conductive material to form a via electrically coupled to the conductive line.
(canceled)
A method comprising:
- forming a conductive line in a first dielectric layer, with a first top surface of the conductive line substantially coplanar with a second top surface of the first dielectric layer;
- forming a second dielectric layer over the conductive line and the first dielectric laver;
- performing a first etching step to etch the second dielectric layer and the first dielectric layer to form an opening extending into the first dielectric laver;
- performing a second etching step to remove a corner portion of the conductive line, wherein the opening is expanded by the second etching step
- selectively forming a conductive cap on exposed portions of the conductive line, wherein a first portion of a lower portion of the opening lower than a top surface of the conductive line is filled by the conductive cap, and a second portion of the lower portion of the opening remains unfilled by the conductive cap;
- and
- filling the opening with a conductive material to form a via electrically coupled to the conductive line.
-25. (canceled)
A method comprising:
- forming a first conductive line in a first dielectric layer;
- forming a first metal cap over and contacting the first conductive line;
- forming an etch stop layer over the first metal cap and the first dielectric layer;
- forming a second dielectric layer over the etch stop layer;
- performing a first step to etch the second dielectric layer, the etch stop layer, and the first dielectric layer to form a trench and a via opening underlying the trench, wherein a portion of the first metal cap is exposed to the via opening and the trench, and a portion of the first dielectric layer remains between a bottom portion of the via opening and a sidewalls of the first conductive line;
- performing a second etching step to remove a portion of the first metal cap, a portion of the first conductive line, and the portion of the first dielectric layer to form a recess in the first metal cap and the first conductive line, with the recess joined to the via opening and the trench;
- and
- filling the trench and the via opening with a conductive material to form a second conductive line and a via, respectively.
(canceled)
Dependencies are inferred from the claim text.