Ti-Nb Sputtering Target Composition for Low-Oxygen Particle Suppression
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Solution Overview
Problem
Current Ti—Nb alloy sputtering targets face challenges with high oxygen content and hardness, leading to particle generation and processing issues during sputtering, particularly due to the difficulties in melting and uniformity caused by the high melting point of Nb and the resulting material characteristics.
Innovation Solution
A Ti—Nb alloy sputtering target with an oxygen content of 400 wtppm or less and Vicker's hardness of 400 Hv or less is achieved by adjusting the raw material shape and melting conditions, specifically by cutting the Nb material into small pieces and adding it multiple times during vacuum skull melting, ensuring uniformity and reducing oxygen adsorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If powder metallurgy method is used to prepare Ti-Nb alloy, then molding is easy, but oxygen content is high and film quality deteriorates
Solution Approach 1:
The patent changes the fundamental preparation parameter from powder metallurgy to melting/casting method. This parameter change transforms the material formation process, enabling low oxygen content (≤400 wtppm) while maintaining manufacturability through controlled cooling and solidification processes that produce homogeneous alloy ingots suitable for sputtering target fabrication.
Solution Approach 2:
The patent employs vacuum skull melting technology that operates in a vacuum environment. This inert atmosphere prevents oxygen contamination during the melting and casting process, ensuring the oxygen content remains ≤400 wtppm. The vacuum environment also eliminates oxidation of the molten alloy, preserving material purity.
2Manufacturing precision
If vacuum skull melting is used to prepare Ti-Nb alloy, then oxygen content is reduced, but melting uniformity is poor due to high melting point difference
Solution Approach 1:
The patent applies preliminary action by pre-heating the vacuum skull melting apparatus and preparing the charge materials before the actual melting process. The apparatus is pre-heated to reduce thermal shock, and materials are pre-processed to ensure proper melting behavior despite the large melting point difference between Ti and Nb.
Solution Approach 2:
The patent optimizes melting parameters including heating rate, holding temperature, and cooling rate. By controlling these parameters, the process achieves uniform melting and solidification despite the 800°C melting point difference between Ti and Nb, ensuring homogeneous alloy composition and consistent oxygen content throughout the ingot.
3Device complexity
If Nb material is added in large pieces during melting, then processing is simple, but oxygen adsorption increases and uniformity decreases
Solution Approach 1:
The patent applies segmentation by dividing the Nb material into small pieces or granules before adding to the melting process. This segmentation increases the surface area-to-volume ratio, promoting uniform heat distribution and oxygen exclusion during melting. The segmented Nb material melts more uniformly and integrates better with Ti, achieving homogeneous alloy composition.
Solution Approach 2:
The patent changes the physical state parameter of Nb material from large pieces to small pieces or granules. This parameter change improves melting behavior by enhancing heat transfer efficiency and reducing oxygen adsorption. The smaller particle size allows for more uniform dissolution of Nb into the molten Ti, ensuring compositional uniformity in the final alloy.
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 suppresses particle generation during sputtering, improves workability, and achieves a favorable surface texture, enhancing film adhesion and heat resistance while reducing production costs.
Implementation Method 1
it has been found that a low-hardness Ti—Nb alloy can be melted and synthesized by properly adjusting a raw material shape and melting conditions
Implementation Method 2
Patent Document 5 discloses a Ti alloy sputtering target prepared via melting/casting, but this technology merely suggests melting Nb having an ultrahigh melting point and a Ti material, which has a melting point difference of nearly 800° C. in comparison to Nb, via vacuum skull melting
Implementation Method 3
a Ti—Nb alloy sputtering target capable of suppressing the generation of particles during sputtering
Data Source
AI summary
Provided is a Ti—Nb alloy sputtering target containing 0.1 to 30 at % of Nb, the remainder of Ti and unavoidable impurities; and the Ti—Nb alloy sputtering target is characterized by having an oxygen content of 400 wtppm or less. Since the target in the present disclosure has a favorable surface texture with a low oxygen content and is readily processable due to the low hardness of the target, the Ti—Nb alloy sputtering target yields a superior effect of being able to suppress the generation of particles during sputtering.