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US 12,660,586 B2Granted
Via structure and methods for forming the same
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsMeng-Pei Lu, Tz-Jun Kuo, Shin-Yi Yang, Ming-Han Lee
Life of this patent
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Abstract
Vias and methods of making the same. The vias including a middle portion located in a via opening in an interconnect-level dielectric layer, a top portion including a top head that extends above the via opening and extends laterally beyond upper edges of the via opening and a bottom portion including a bottom head that extends below the via opening and extends laterally beyond lower edges of the via opening. The via may be formed from a refractory material.
Claims20
A method of making an interconnect comprising:
- forming a first trench in a first interconnect-level dielectric layer;
- filling the first trench with a first copper fill layer;
- depositing a second interconnect-level dielectric layer over the first copper fill layer and the first interconnect-level dielectric layer;
- etching the second interconnect-level dielectric layer to form a second trench;
- etching the second interconnect-level dielectric layer to form a via opening in the second interconnect-level dielectric layer, the via opening extending through the second interconnect-level dielectric layer and exposing a top surface of the copper fill layer in the first trench;
- etching a portion of the first copper fill layer in the first trench to form a cavity in the first copper fill layer in the first trench, the cavity including an undercut under the second interconnect-level dielectric layer, comprising:
- wet or dry etching of a first portion of the first copper fill layer;
- partially oxidizing a second portion of the first copper fill layer in the first trench to form a copper oxide portion;
- and
- etching the copper oxide portion;
- depositing a refractory material in the cavity such that the refractory material:
- fills the cavity in the copper fill layer in the first trench, including the undercut, to form a bottom portion of a via having a bottom head;
- fills the via opening in the second interconnect-level dielectric layer;
- and
- forms a top portion having a top head in the second trench that extends above the via opening and extends laterally beyond upper edges of the via opening;
- forming a top conformal liner over the top head;
- and
- filling the second trench with a second copper fill layer.
15 more elements
A method of making an interconnect, comprising:
- forming a first line structure in a first interconnect-level dielectric layer, wherein the first line structure comprises a copper fill layer;
- etching the copper fill layer to form a cavity in the first line structure, wherein the cavity has a first width;
- depositing a refractory material in the cavity such that the refractory material fills the cavity in the copper fill layer;
- forming a capping layer over the first line structure;
- forming an etch stop layer over the first interconnect-level dielectric layer and the first line structure, wherein the capping layer is located between the first line structure and the etch stop layer and wherein the etch stop layer extends laterally beyond the capping layer;
- forming a second interconnect-level dielectric layer over the first line structure and the first interconnect-level dielectric layer, wherein the etch stop layer is located between the first interconnect-level dielectric and the second interconnect-level dielectric;
- etching the second interconnect-level dielectric layer and the etch stop layer to form a via opening in the second interconnect-level dielectric layer;
- etching portions of the capping layer and copper fill layer by etching though the via opening to form an opening through the capping layer and a second cavity, wherein the opening through the capping layer has a second width that is smaller than the first width, and wherein the refractory material that fills the first cavity is exposed;
- and
- depositing the refractory material in the via opening and the second cavity to thereby form a via comprising a bottom portion formed in contact with the first line structure and a middle portion that extends within the second interconnect-level dielectric layer.
7 more elements
A method of making an interconnect, comprising:
- forming a first line structure in a first interconnect-level dielectric layer, wherein the first line structure includes a diffusion barrier layer and an adhesion layer over the diffusion barrier layer;
- depositing a second interconnect-level dielectric layer over the first line structure and the first interconnect-level dielectric layer;
- etching the second interconnect-level dielectric layer and the first line structure to form a via opening in the second interconnect-level dielectric layer;
- etching a first portion of the first line structure through the via opening;
- partially oxidizing a second portion of the first line structure through the via opening;
- etching the oxidized second portion of the first line structure to form a cavity in the first line structure;
- and
- forming a first conformal liner within the cavity in the first line structure.
5 more elements
Dependencies are inferred from the claim text.