Doped PVD Target Composition for Electromigration Barrier Layers

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Solution Overview

Problem

As integrated circuits are scaled to smaller dimensions, metal interconnects become increasingly susceptible to electromigration, leading to reliability issues and potential failure, necessitating an improvement in diffusion barrier layers to prevent conductive metal diffusion into adjacent dielectric layers.

Innovation Solution

A PVD target with a sputtering source material and intentionally introduced dopants, such as nickel, is used to form a diffusion barrier layer during the physical vapor deposition process, enhancing the electromigration properties and deposition rate, thereby reducing electromigration effects and increasing the lifetime of integrated circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If metal interconnects are scaled to smaller dimensions, then device density and integration are improved, but susceptibility to electromigration increases leading to reliability degradation

Engineering Contradiction:

Improvedevice densityVSAvoidelectromigration resistance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

A diffusion barrier layer is introduced as an intermediary between the metal interconnect and the dielectric layer. This barrier layer prevents direct interaction between conductive metal atoms and the dielectric, blocking electromigration-induced diffusion and protecting the reliability of scaled interconnect structures.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The diffusion barrier layer is formed as a composite structure containing a sputtering source material (such as titanium or tantalum) intentionally doped with nickel. This composite material combines the diffusion barrier properties of the source material with the electromigration resistance enhancement provided by nickel dopants, creating a multi-functional layer that addresses both density scaling and reliability concerns.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If conventional PVD targets without dopants are used, then manufacturing simplicity is maintained, but electromigration properties of diffusion barrier layers are insufficient

Engineering Contradiction:

Improvetarget fabrication simplicityVSAvoidelectromigration resistance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The composition parameters of the PVD target are modified by intentionally introducing nickel dopants at controlled concentrations (e.g., 0.025-0.04 ppm). This parameter change transforms the diffusion barrier layer's electromigration resistance without fundamentally altering the manufacturing process, allowing conventional PVD equipment to produce enhanced barrier layers with improved reliability properties.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The introduction of dopants into the PVD target improves the electromigration characteristics of the diffusion barrier layer, reducing the susceptibility of metal interconnects to electromigration, thereby enhancing the reliability and performance of integrated circuits.

Implementation Method 1

positioning the substrate into a physical vapor deposition (PVD) chamber facing a PVD target

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Implementation Method 2

sputtering the PVD target to deposit a diffusion barrier layer

Methodology Applied

Scientific EffectSputtering: Sputtering

Data Source

PatentUS20250092508A1PVD target design and semiconductor devices formed using the same

Publication Date: 2025.03.20 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A physical vapor deposition (PVD) target for performing a PVD process is provided. The PVD target includes a backing plate and a target plate coupled to the backing plate. The target plate includes a sputtering source material and a dopant, with the proviso that the dopant is not impurities in the sputtering source material. The sputtering source material includes a diffusion barrier material.