Metal heterojunction structure with capping metal layer

Patent metadata

Field	Value
Publication number	US-2020098591-A1
Application number	US-201916400620-A
Country	US
Kind code	A1
Filing date	May 1, 2019
Priority date	Sep 26, 2018
Publication date	Mar 26, 2020
Grant date	—

Abstract

The current disclosure describes techniques of protecting a metal interconnect structure from being damaged by subsequent chemical mechanical polishing processes used for forming other metal structures over the metal interconnect structure. The metal interconnect structure is receded to form a recess between the metal interconnect structure and the surrounding dielectric layer. A metal cap structure is formed within the recess. An upper portion of the dielectric layer is strained to include a tensile stress which expands the dielectric layer against the metal cap structure to reduce or eliminate a gap in the interface between the metal cap structure and the dielectric layer.

First claim

1 . A semiconductor structure, comprising:
a substrate; a semiconductor device over the substrate; a first interconnect structure within a first dielectric layer and connecting to a terminal of the semiconductor device; a first cap structure over the first interconnect structure and contacting the first interconnect structure, the first cap structure at least partially within the first dielectric layer; and a second interconnect structure over the first cap structure and contacting the first cap structure.

2 . The semiconductor structure of claim 1 , wherein an upper portion of the first dielectric layer includes a tensile stress against an interface between the first dielectric layer and the first cap structure.

3 . The semiconductor structure of claim 2 , wherein the first cap structure is at least partially within the upper portion of the first dielectric layer.

4 . The semiconductor structure of claim 2 , wherein the upper portion of the first dielectric layer includes one or more of germanium, silicon, carbon, nitrogen, phosphorus or boron.

5 . The semiconductor structure of claim 1 , wherein the first cap structure includes a same conductive material as the second interconnect structure.

6 . The semiconductor structure of claim 1 , wherein the first cap structure includes a different conductive material from the first interconnect structure.

7 . The semiconductor structure of claim 6 , wherein a conductive material of the first cap structure is different from a conductive material of the first interconnect structure in reacting to at least one of an acidic solution or an alkaline solution.

8 . The semiconductor structure of claim 6 , wherein one of the first cap structure or the first interconnect structure is tungsten and another one of the first cap structure or the first interconnect structure is one or more of cobalt or copper.

9 . The semiconductor structure of claim 1 , wherein the first cap structure extends laterally beyond the second interconnect structure at least in one direction.

10 . The semiconductor structure of claim 1 , wherein the first cap structure includes a different diameter than the second interconnect structure.

11 . The semiconductor structure of claim 1 , wherein the first cap structure misaligns with the second interconnect structure.

12 . The semiconductor structure of claim 1 , further comprising a second cap structure directly over the second interconnect structure and a third interconnect structure directly over the second cap structure.

13 . A semiconductor structure, comprising:
a substrate; a dielectric layer over the substrate; an conductive via structure within the dielectric layer, an upper surface of the conductive via structure being lower than an upper surface of the dielectric layer adjacent to the conductive via structure; and a conductive cap structure directly over the conductive via structure, an upper surface of the conductive cap structure being one of substantially at a same level with or higher than the upper surface of the dielectric layer adjacent to the conductive via structure.

14 . The semiconductor structure of claim 13 , wherein the conductive cap structure extends laterally beyond the conductive via structure at least in one direction.

15 . The semiconductor structure of claim 13 , wherein the conductive cap structure misaligns with the conductive via structure.

16 . A method, comprising:
forming a first metal structure within a first dielectric layer, an upper surface of the first metal structure being lower than an upper surface of the first dielectric layer that is adjacent to the upper surface of the first metal structure; forming a second metal structure over the upper surface of the first metal structure; and straining an upper portion of the first dielectric layer to have a tensile stress.

17 . The method of claim 16 , wherein the straining including implanting ions of one or more of germanium, silicon, carbon, nitrogen, phosphorus or boron into the upper portion of the first dielectric layer.

18 . The method of claim 16 , further comprising forming a third metal structure directly over the second metal structure, the third metal structure being surrounded by a second dielectric layer.

19 . The method of claim 16 , wherein the forming the first metal structure within the first dielectric layer includes forming a recess portion between the first dielectric layer and the first metal structure by removing an upper portion of the first metal structure.

20 . The method of claim 16 , wherein the straining an upper portion of the first dielectric layer increases a volume of the upper portion of the first dielectric layer.

Assignees

• Taiwan Semiconductor Mfg Co Ltd

Inventors

• Lin Yi-Sheng
• Liu Chi-Jen
• Chen Kei-Wei
• Chen Liang-Guang
• Kung Te-Ming
• Hong William Weilun
• Shen Chi-Hsiang
• Ho Chia-Wei
• Hsu Chun-Wei
• Cheng Yang-Chun

Classifications

• H10W20/4437

  the principal metal being a transition metal · CPC title

• C09G1/02

  containing abrasives or grinding agents {(abrasives as such C09K3/14; polishing of semi-conductors H10P52/40)} · CPC title

• H10W20/4441

  the principal metal being a refractory metal · CPC title

• H10W20/4421

  the principal metal being copper · CPC title

• H10W20/4403

  based on metals, e.g. alloys, metal silicides (H10W20/4484 takes precedence) · CPC title