Sb-Te Alloy Sputtering Target Grain Refinement
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Solution Overview
Problem
The generation of particles, abnormal electrical discharge, nodules, cracks, and fractures during the sputtering process of Sb—Te alloy targets for phase-change recording films is a significant issue due to high oxygen content and inadequate target strength, leading to poor film quality and reduced production yield.
Innovation Solution
An Sb—Te alloy sintered compact sputtering target with a surface roughness of 0.4 μm or less, purity of 4N or more, and average crystal grain size of 50 μm or less, using gas atomized powder and incorporating elements like Ag, In, Ga, Ti, Sn, Au, Pt, and Pd, is developed to inhibit particle generation and improve target stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional atomization method is used to manufacture Sb-Te alloy powder, then the manufacturing process is simple, but the target strength is insufficient and the structure is not refined and homogenized
Solution Approach 1:
The patent applies parameter changes by controlling the particle size distribution of the powder (D10-D90 ratio of 1.2 or less) and adjusting sintering parameters (temperature, pressure, time) to achieve both sufficient target strength and refined homogeneous structure. This resolves the contradiction by optimizing the physical parameters of the powder and sintering process.
Solution Approach 2:
The patent uses composite materials by combining Sb-Te alloy powder with specific particle size distribution and controlled oxygen content (500 ppm or less) to create a sintered compact that achieves both ease of manufacture and sufficient strength. The composite structure of fine particles bonded together provides the desired properties.
2Ease of manufacture
If the oxygen content in sintering powder is high, then the manufacturing process is less stringent, but particles and nodules are generated during sputtering
Solution Approach 1:
The patent applies inert atmosphere by conducting the sintering process in a vacuum or inert gas environment to prevent oxygen contamination. The powder is also protected during storage and handling. This creates an inert environment that prevents oxidation and reduces particle generation during sputtering while maintaining manufacturing feasibility.
Solution Approach 2:
The patent applies preliminary action by pre-controlling the oxygen content in the powder to 500 ppm or less before sintering, and by pre-preparing the powder with appropriate particle size distribution. This preliminary preparation prevents particle and nodule generation during the sputtering process.
3Manufacturing precision
If the target surface roughness is high, then the manufacturing tolerance is easier to achieve, but abnormal electrical discharge and micro arcing occur during sputtering
Solution Approach 1:
The patent applies parameter changes by controlling the surface roughness to Ra≤0.4 μm through optimized sintering parameters and powder characteristics. This parameter control prevents abnormal electrical discharge and micro arcing during sputtering while maintaining manufacturability.
4Ease of manufacture
If the crystal grain size is large, then the sintering process is simpler, but cracks and fractures occur during sputtering
Solution Approach 1:
The patent applies parameter changes by controlling the crystal grain size to 50 μm or less through optimized sintering temperature, pressure, and time parameters. This grain size control prevents cracks and fractures during sputtering while maintaining reasonable manufacturing simplicity.
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 effectively reduces particle generation, prevents abnormal electrical discharge, and maintains a smooth eroded target surface, enhancing the quality and stability of phase-change recording layers.
Implementation Method 1
sintering a compact subject to cold or hot pressure forming using powder
Implementation Method 2
physically colliding positive ions such as Ar ions to a target disposed on a negative electrode, discharging the material configuring the target with such collision energy
Data Source
AI summary
Provided is an Sb—Te alloy sintered compact sputtering target having at least Sb or Te as its primary component, wherein surface roughness Ra is 0.4 μm or less, purity excluding gas components is 4N or more, content of gas components as impurities is 1500 ppm or less, and average crystal grain size is 50 μm or less. With this Sb—Te alloy sintered compact sputtering target, the density of defects having a maximum length of 10 μm or greater arising in a surface finish by machining is 80 or less in an 800 μm square. Thus, the Sb—Te alloy sputtering target structure can be uniformalized and refined, generation of cracks in the sintered target can be inhibited, and generation of arcing during sputtering can be inhibited. Further, surface ruggedness caused by sputter erosion can be reduced in order to obtain a high quality Sb—Te alloy sputtering target.