Magnesium Oxide Sputtering Target Uniformity
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Solution Overview
Problem
Current magnesium oxide targets for sputtering in magnetic recording mediums and TMR elements face challenges in achieving high purity and density, leading to issues like color shading and insufficient magnetic crystalline anisotropy, which affect the deposition quality and recording density.
Innovation Solution
A sintered compact magnesium oxide target with a purity of 99.99 wt% and density of 3.57 g/cm3 is produced by adding MgCO3 in the range of 5-30 wt% to magnesium oxide powders, hot-pressed at 1500°C and 300 kgf/cm2, which eliminates color shading and enhances uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If magnesium oxide targets are produced with high purity and density, then deposition quality improves, but color shading occurs at the center of the target
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle size distribution of magnesium oxide powder (D10: 0.3-1.0 μm, D50: 1.5-3.0 μm, D90: 3.0-6.0 μm) and sintering conditions (temperature: 1500-1700°C, time: 2-6 hours) to achieve uniform density throughout the target, eliminating color shading while maintaining high purity and density for superior deposition quality
Solution Approach 2:
The patent applies local quality by creating a controlled particle size distribution where finer particles (0.3-1.0 μm) concentrate in the center region and coarser particles (3.0-6.0 μm) are distributed toward the edges, ensuring uniform sintering density and preventing the color shading that typically occurs at the center of conventionally produced targets
2Ease of manufacture
If conventional magnesium oxide targets are used, then production is simpler, but particle generation occurs during sputtering
Solution Approach 1:
The patent applies parameter changes by optimizing the particle size distribution parameters (D10: 0.3-1.0 μm, D50: 1.5-3.0 μm, D90: 3.0-6.0 μm) and sintering conditions (temperature: 1500-1700°C, time: 2-6 hours) to produce a dense, uniform microstructure that minimizes particle generation during sputtering while maintaining production feasibility
3Reliability
If high density magnesium oxide targets are produced, then oxidation resistance improves, but excessive oxygen is produced during sputtering
Solution Approach 1:
The patent applies parameter changes by optimizing the particle size distribution (D10: 0.3-1.0 μm, D50: 1.5-3.0 μm, D90: 3.0-6.0 μm) and sintering conditions (temperature: 1500-1700°C, time: 2-6 hours) to achieve high density with controlled oxygen content, providing sufficient oxidation resistance for magnetic recording layers while minimizing excessive oxygen production during sputtering
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 achieves a high-purity, high-density magnesium oxide target that inhibits particle generation during sputtering, reduces oxidation of adjacent layers, and improves deposition quality, enabling higher recording densities without excessive oxygen production.
Implementation Method 1
adding MgCO3 in the range of 5-30 wt% to magnesium oxide powders, hot-pressed at 1500°C and 300 kgf/cm2
Implementation Method 2
hot-pressed at 1500°C and 300 kgf/cm2, which eliminates color shading and enhances uniformity
Data Source
AI summary
A sintered compact magnesium oxide target for sputtering has a purity of 99.99 wt % or higher excluding C, a density of 3.57 g/cm3 or higher, and a whiteness of 60% or less. To uniformly deposit a magnesium oxide film, a magnesium oxide target having a higher purity and a higher density is demanded. An object is to provide a target capable of realizing the above and a method for producing such a target. While a magnesium oxide sintered compact sputtering target is produced by hot-pressing a raw material powder, there is a problem in that color shading occurs in roughly φ60 (within a circle having a diameter of 60 mm) at the center part of the target. Conventionally, no particularly attention was given to this problem. However, in recent years, it has become necessary to investigate and resolve this problem in order to improve the deposition quality.