Browse Prior Art Database

Embedded Metallic Liner

IP.com Disclosure Number: IPCOM000201786D
Publication Date: 2010-Nov-23
Document File: 2 page(s) / 56K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a new structure in which the metal dialectic cap is embedded in the interconnect during electromigration. This enhances reliability by providing better redundancy. In addition, unlike other schemes which provide a top metal cap, this structure does not require new unit processes for manufacturing.

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Embedded Metallic Liner


The current density in interconnect structures is increasing due to scaling of the

structures. This increased current density is expected to degrade EM related reliability. For conventional structures, the Cu/dielectric cap interface is the weakest interface with

regard to electromigration fails. It has been shown that a Cu -metal interface provides

much better electromigration resistance. Examples of the metal include Ta and CoWP. No known, relevant solutions exist.

The invention introduces a new structure in which the metal cap is embedded in the

interconnect. This enhances reliability by providing better redundancy. In addition,

unlike other schemes which provide a top metal cap, this structure does not require new

unit processes for manufacturing.

In a sample embodiment, the proposed structure is an embedded liner only at the

horizontal, not the vertical, sidewalls. (Figure 1) This allows limited impact on

resistance In addition, it enhances the mechanical integrity of the interconnect structure. Figure 1: Proposed structure in the current case

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The proposed method includes the following steps: (Figure 2)

1. Post pattern and liner deposition; liner including Ta, Co, Ru, Ir

2. Post PVD Cu deposition

3. Cu reflow; sidewall Cu thickness <5nm

4. Remove Cu from fields and sidewalls by wet etching

5. Selective metal cap deposition (e.g., CoWP, Co, Ru)

6. Post Cu plating and CMP


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