CoFeB Sputtering Target with Low Hydrogen for High Strength
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Solution Overview
Problem
The existing method of sintering atomized powder to produce a sputtering target material results in a decrease in mechanical strength, as evident in Japanese Patent Laid-Open Publication No. 2004-346423, which does not yield a favorable target material.
Innovation Solution
A sputtering target material with a hydrogen content of 20 ppm or less, comprising 10 to 50% B and 0 to 20% of specific elements like Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Ru, Rh, Ir, Ni, Pd, Pt, Cu, and Ag, with the balance being Co and Fe, and satisfying specific particle size conditions, is developed to enhance mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If simple sintering of atomized powder is used to produce sputtering target material, then the production process is simple and effective, but the mechanical strength of the target material decreases
Solution Approach 1:
The patent applies parameter changes by controlling the hydrogen content to 20 ppm or less through specific sintering conditions and powder treatment processes. This parameter control transforms the simple sintering process into one that produces high-strength target material while maintaining manufacturing simplicity.
Solution Approach 2:
The patent uses composite material principles by creating a sputtering target with specific compositional ratios (10-50% B, 0-20% of specific elements, balance Co and Fe) and controlling the microstructure through hydrogen content reduction. This composite approach achieves both ease of manufacture and high mechanical strength.
2Strength
If hydrogen content is reduced to 20 ppm or less, then the mechanical strength increases to 200 MPa or more, but the production process becomes more complex
Solution Approach 1:
The patent applies preliminary action by pre-treating the atomized powder to reduce hydrogen content before sintering, and by establishing specific compositional ratios in advance. This preliminary preparation simplifies the overall process while achieving the required 200 MPa strength.
Solution Approach 2:
The patent uses parameter changes by precisely controlling hydrogen content (≤20 ppm) and compositional parameters during production. These parameter specifications, when implemented systematically, achieve high strength without excessive process complexity.
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 resulting sputtering target material exhibits excellent mechanical strength, with a bending strength of 200 MPa or more, suitable for producing alloy thin films in MTJ elements and magnetic recording media.
Implementation Method 1
A CoFeB thin film of a magnetic tunneling junction (MTJ) element is formed by sputtering a CoFeB target
Implementation Method 2
a sputtering target material produced by sintering an atomized powder
Data Source
AI summary
A method of making a sputtering target in which an atomized powder including, in at. %, 10 to 50% of B, 0 to 20% in total of one or more elements selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Ru, Rh, Ir, Ni, Pd, Pt, Cu, and Ag, and a balance of one or both of Co and Fe, and unavoidable impurities is provided. Fine particles are removed from the atomized powder to obtain a powder having a particle distribution where the cumulative volume of particles having a particle diameter of 5 μm or less is 10% or less, and the cumulative volume of particles having a particle diameter of 30 μm or less is 5-40%. The obtained powder is sintered to form a sputtering target comprising a sintered body. The sputtering target comprises hydrogen of 20 ppm or less.