Co-Fe-B Sputtering Target Microstructure for Low-Particle Deposition
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Solution Overview
Problem
Existing methods for producing Co—Fe—B alloy sputtering target materials with high boron content face significant particle generation during sputtering, leading to quality deterioration and reduced yield in magnetic films, particularly when the boron content exceeds 33 at. %.
Innovation Solution
A production method that coarsens the (CoFe)2B and (CoFe)B phases in the target material, forming a metallographic structure where the boundary length between these phases satisfies a specific condition, reducing particle generation during sputtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the boron content proportion in the Co-Fe-B alloy target material is increased to improve magnetic performance and achieve high TMR signals, then the magnetic performance of the obtained magnetic layer is improved, but the frequency of particle generation during sputtering increases noticeably
Solution Approach 1:
The invention changes the microstructural parameters of the target material by controlling the size and distribution of boride phases. Specifically, it maintains a dual-phase structure with both fine and coarse boride phases, where the coarse phases (≥1 μm) act as particle sources that can be controlled and minimized. This parameter change in microstructure allows high boron content (33-50 at.%) to be achieved while controlling particle generation frequency during sputtering.
2Productivity
If conventional methods are used to produce Co-Fe-B alloy target materials with high boron content, then the target material can be manufactured, but significant particle generation occurs during sputtering leading to quality deterioration and reduced yield
Solution Approach 1:
The invention applies local quality by creating a non-uniform microstructure with different regions having different boride phase characteristics. The target material contains both fine boride phases (distributed throughout) and coarse boride phases (≥1 μm in size). This local differentiation allows the material to maintain high boron content while controlling where and how particles are generated during sputtering, thereby improving film quality without sacrificing manufacturing efficiency.
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 method efficiently produces a high-performance and high-quality magnetic film with reduced particle generation, improving yield and suitability for magnetic devices like magnetic heads and MRAMs.
Implementation Method 1
This magnetic layer is a thin film obtained by sputtering using a target material composed of a Co—Fe—B alloy
Implementation Method 2
a sintering step of sintering a mixed powder obtained by mixing a first powder and a second powder
Data Source
AI summary
Provided is a method of producing a target material with reduced particle generation during sputtering, which is a method of producing a sputtering target material whose material is an alloy M, including a sintering step of sintering a mixed powder obtained by mixing a first powder and a second powder. A material of the first powder is an alloy M1 in which the proportion of a B content is from 40 at. % to 60 at. %. A material of the second powder is an alloy M2 in which the proportion of a B content is from 20 at. % to 35 at. %. The proportion of a B content in the mixed powder is from 33 at. % to 50 at. %. A metallographic structure including a (CoFe)2B phase and a (CoFe)B phase is formed in the sintering step. A boundary length per unit area Y (1/μm), which is obtained by measuring a boundary length between the (CoFe)2B phase and the (CoFe)B phase using a scanning electron microscope, and a proportion X (at. %) of a B content of the alloy M satisfy the expressionY<−0.0015×(X−42.5)2+0.15.