Copper Interconnect Via Plug Structure for Corrosion Control

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Solution Overview

Problem

The deterioration of metal interconnects in semiconductor devices due to the influence of via plugs, specifically caused by high chlorine and oxygen concentrations, leads to copper corrosion and reliability issues.

Innovation Solution

The semiconductor device is designed with a via plug structure that includes a barrier metal layer with a chlorine concentration not exceeding 5.0×10^21 atoms/cm^3 and an oxygen concentration at the interface with the plug material layer not exceeding 5.0×10^21 atoms/cm^3, thereby preventing corrosion of the interconnect material layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a via plug is disposed on a metal interconnect, then electrical connection is achieved, but the metal interconnect deteriorates due to high chlorine and oxygen concentrations from the via plug

Engineering Contradiction:

Improveinterconnect reliabilityVSAvoidchlorine and oxygen concentration

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The via plug is divided into multiple layers: a first barrier metal layer (TiN) directly contacting the interconnect, and a second barrier metal layer (Ti) on top. This segmentation isolates the interconnect from harmful chlorine and oxygen in the plug material, preventing deterioration while maintaining electrical connection.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first barrier metal layer (TiN) acts as an intermediary between the copper interconnect and the via plug material. It prevents direct contact between harmful substances (chlorine, oxygen) and the interconnect, thereby protecting the interconnect from corrosion and deterioration.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If conventional via plug structure is used, then manufacturing is simplified, but copper corrosion occurs due to chlorine diffusion from the via plug

Engineering Contradiction:

Improvevia plug fabricationVSAvoidchlorine diffusion

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The barrier metal layer is segmented into two distinct layers with different compositions and functions. The first layer (TiN) prevents chlorine diffusion to the interconnect, while the second layer (Ti) provides additional barrier protection and facilitates plug formation, maintaining manufacturing feasibility.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The via plug structure uses composite materials - a combination of TiN and Ti layers - to achieve both protection against chlorine diffusion and ease of manufacture. The TiN layer provides superior chlorine barrier properties while Ti layer maintains compatibility with conventional manufacturing processes.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS12205887B2Semiconductor device and method for manufacturing the semiconductor device preliminary class

Publication Date: 2025.01.21 KIOXIA CORP

AI summary

A semiconductor device includes an interconnect including (i) a first layer, and (ii) a second layer provided on the first layer and including copper. The device also includes a plug provided on the interconnect and including (a) a third layer including titanium and nitrogen, and (b) a fourth layer provided on the third layer and including tungsten. A concentration of chlorine in the third layer is less than or equal to 5.0×1021 atoms/cm3, and a concentration of oxygen at the interface between the third layer and the fourth layer is less than or equal to 5.0×1021 atoms/cm3.