Integrated Sputtering Target Flange Strength via Local Plastic Working

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Solution Overview

Problem

Conventional semiconductor copper lines face issues with mechanical strength during sputtering, leading to deformation and non-uniform thin film formation, while existing solutions to enhance strength alter sputtering characteristics.

Innovation Solution

A copper-manganese-alloy sputtering target with a strengthened flange part, achieved through specific Vicker's hardness and yield stress levels, and a Cu—Mn alloy composition, maintains original sputtering characteristics and prevents deformation during sputtering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the thickness of the target is increased to prevent deformation during sputtering, then the mechanical strength is improved, but the sputtering characteristics are altered and product performance deteriorates

Engineering Contradiction:
Improvemechanical strengthVSAvoidproduct performance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention applies local quality by performing plastic working only on the flange part of the target to enhance its mechanical strength, while leaving the sputtering surface unchanged to preserve sputtering characteristics. This selective treatment ensures the flange part has sufficient strength to prevent deformation during sputtering, while the film-forming surface maintains its original properties for producing high-performance semiconductor products.

Inventive Principle:
Principle #3Local quality

2Strength

If plastic working is performed on the entire target to increase mechanical strength, then deformation is prevented, but the sputtering characteristics are varied and product performance deteriorates

Engineering Contradiction:
Improvemechanical strengthVSAvoidthin film uniformity
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The invention applies local quality by performing plastic working only on the flange part of the target to enhance its mechanical strength, while leaving the sputtering surface unchanged to preserve sputtering characteristics. This selective treatment ensures the flange part has sufficient strength to prevent deformation during sputtering, while the film-forming surface maintains its original properties for producing high-performance semiconductor products.

Inventive Principle:
Principle #3Local quality

3Productivity

If the target and backing plate are unified into an integrated structure, then manufacturing cost is reduced by minimizing downtime, but the mechanical strength becomes insufficient and deformation occurs during sputtering

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidmechanical strength
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The invention applies local quality by performing plastic working only on the flange part of the integrated target to enhance its mechanical strength. This localized treatment provides the necessary structural reinforcement at the flange region to prevent deformation during sputtering, while maintaining the integrated structure's productivity benefits of reduced downtime and manufacturing cost.

Inventive Principle:
Principle #3Local quality

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 enhanced mechanical strength of the flange part inhibits target deformation, ensuring uniform thin film formation and improved yield and reliability of semiconductor products with self-diffusion suppression, electron migration resistance, and corrosion resistance.

Implementation Method 1

even in sputtering at high output, it is possible to prevent the deformation such as a warpage of an integrated structure-type target composed of a target and a backing plate made with the same material by increasing the mechanical strength through plastic working of the target

Methodology Applied
Scientific EffectPlastic working: Plasticity

Implementation Method 2

a copper line is generally formed by forming a diffusion barrier layer of such as Ta or TaN in lines or line via holes and then forming a film of copper by sputtering

Methodology Applied
Scientific EffectSputtering: Sputtering

Implementation Method 3

as a copper line material, a copper alloy having a self-diffusion suppression function has been proposed, which is prepared by adding manganese (Mn) to copper (Cu), by forming a barrier layer by itself through a reaction of Mn in the Cu—Mn alloy with oxygen in an insulating film

Methodology Applied
Scientific EffectOxidation: Oxidation

Data Source

PatentUS9704695B2Sputtering target and manufacturing method therefor
Publication Date: 2017.07.11 JX NIPPON MINING & METALS CORP

AI summary

A backing plate integrated sputtering target includes a flange part having a Vicker's hardness (Hv) of 90 or more and a 0.2% yield stress of 6.98×107 N/m2 or more. Enhancing the mechanical strength of only the flange part of the target inhibits the target from being deformed during sputtering, and further, does not vary the original sputtering characteristics. Consequently, the target can form a thin film having excellent uniformity. This can improve the yield and the reliability of semiconductor products, which have been progressing in miniaturization and integration.