Sintered Refractory Metal Sputtering Target

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Solution Overview

Problem

The existing sputtering targets made from refractory metals like ruthenium, rhodium, and iridium face issues with inferior wettability during plating, high manufacturing costs due to high melting points and fragility, and poor deposition quality due to particle dropout and arcing caused by impurities and structural weaknesses.

Innovation Solution

A sintered sputtering target is developed by adding minor components like tungsten, tantalum, or hafium at specific concentrations to the major components ruthenium, rhodium, or iridium, forming a granular metal phase or alloy phase with controlled grain sizes and impurity levels to enhance bonding and density, reducing particle dropout and arcing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the additive amount of alloy elements is increased to improve wettability, then the plating performance is improved, but metal particles form dots in the matrix structure and drop out during sputtering, generating particles

Engineering Contradiction:
Improveplating wettabilityVSAvoidparticle generation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by precisely controlling the additive amount of alloy elements to be within a specific range (0.01-10 wt%). This quantitative parameter optimization prevents excessive alloying that would cause particle dropout, while maintaining sufficient additive content to improve plating wettability. The parameter control directly addresses the contradiction by finding the optimal balance point.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by ensuring uniform distribution of alloy elements throughout the target matrix. By controlling the microstructure and preventing localized clustering of alloy particles, the patent maintains consistent wettability across the target surface while preventing the formation of discrete particle dots that would dropout during sputtering.

Inventive Principle:
Principle #3Local quality

2Object-generated harmful factors

If the content of alloy elements is low to avoid particle dropout, then particle generation is reduced, but the wettability during plating remains inferior

Engineering Contradiction:
Improveparticle generationVSAvoidplating wettability
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent applies parameter changes by establishing a minimum threshold for alloy element content (0.01 wt%). This ensures sufficient additive concentration to improve plating wettability while maintaining the content below levels that would cause particle dropout. The parameter optimization resolves the contradiction by identifying the effective minimum concentration.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent substitutes mechanical mixing with controlled sintering processes to achieve uniform alloy element distribution. By using sintering technology, the patent can achieve homogeneous distribution of small amounts of alloy elements throughout the target matrix, ensuring improved wettability without localized clustering that would cause particle dropout.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If gas components and impurities are present in the target, then the manufacturing process is simpler, but these impurities are collected at interfaces and cause arcing and particles in sputtering

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidarcing and particles
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent applies inert atmosphere by conducting the sintering process in a controlled atmosphere that prevents gas component absorption and impurity formation. By using inert or reducing atmosphere during sintering, the patent eliminates sources of gas impurities that would otherwise be collected at interfaces and cause arcing during sputtering, while maintaining manufacturing feasibility.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent applies preliminary action by performing vacuum treatment and impurity removal during the target manufacturing process before the sputtering operation. By预先 removing gas components and impurities during fabrication, the patent prevents their accumulation at interfaces that would later cause arcing and particle generation, thereby resolving the contradiction between manufacturing simplicity and sputtering quality.

Inventive Principle:
Principle #10Preliminary action

4Strength

If the sintering density is increased to improve target strength, then the target strength is enhanced, but the manufacturing complexity increases

Engineering Contradiction:
Improvetarget strengthVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by optimizing sintering conditions including temperature, pressure, and time parameters to achieve high density without requiring excessively complex manufacturing processes. By carefully controlling these parameters within practical ranges, the patent achieves high target strength while maintaining manufacturing feasibility and avoiding undue complexity.

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 solution improves the target structure, deposition quality, and workability by preventing particle dropout, reducing impurities, and eliminating arcing, resulting in a more reliable and efficient semiconductor device deposition material.

Implementation Method 1

a sintered sputtering target is developed by adding minor components like tungsten, tantalum, or hafium at specific concentrations to the major components ruthenium, rhodium, or iridium, forming a granular metal phase or alloy phase with controlled grain sizes and impurity levels

Methodology Applied
Scientific EffectSintering: Sintering

Implementation Method 2

The well known sputtering method is generally used as the means for forming a thin film

Methodology Applied
Scientific EffectSputtering: Sputtering

Data Source

PatentEP2003226B1Sintered sputtering target made of high-melting metals
Publication Date: 2013.04.24 JX NIPPON MINING & METALS CORP
  • EP2003226B1 patent drawingFigure 1

AI summary

Proposed is a sintered sputtering target containing two or more types of refractory metals. In particular, proposed is a sintered sputtering target of refractory metals that is able to improve the target structure to prevent the dropout of metal particles other than the matrix-forming major component, improve the deposition quality as well as the workability of the target by reducing impurities such as gas components, enhancing the density and eliminating the generation of arcing and particles in sputtering. This sintered sputtering target of refractory metals is composed of one or more types of minor components selected from W, Ta and Hf at less than 50at% as well as at least one or more major components selected from Ru, Rh and Ir and inevitable impurities as the remainder. The metal structure of the major component comprises a granular minor component metal phase, or an alloy phase or a compound phase of the major and the minor component having an average grain size of 100µm to 500µm.