HIP Refractory Metal Sputtering Targets With Random Texture
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Solution Overview
Problem
There is a need for alternative sputtering targets, particularly those with a random crystallographic texture, that avoid costly and energy-intensive thermomechanical processing steps, especially for tantalum-containing targets, while maintaining high purity and uniformity in sputtering processes.
Innovation Solution
The method involves producing and consolidating high purity refractory metal powders, such as tantalum, with controlled oxygen content and particle size distribution, using techniques like hot isostatic pressing and scavenging metals to achieve a random crystallographic texture without thermomechanical processing, ensuring the target body's density and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thermomechanical processing is used to achieve desired texture in sputtering targets, then crystallographic texture uniformity is improved, but manufacturing cost and energy consumption increase
Solution Approach 1:
The patent applies preliminary action by controlling the powder metallurgy process parameters (particle size distribution, compaction pressure, sintering temperature and atmosphere) to achieve the desired random crystallographic texture directly during target body formation, eliminating the need for subsequent thermomechanical processing steps to modify texture
Solution Approach 2:
The patent replaces mechanical thermomechanical processing with a controlled powder metallurgy process that uses chemical sintering and gas atmosphere control to achieve texture uniformity, substituting mechanical deformation methods with a chemical-physical consolidation process
2Manufacturing precision
If high purity refractory metal powders are used as starting materials, then sputtering target purity is improved, but oxygen content control becomes more difficult
Solution Approach 1:
The patent employs an inert gas atmosphere (argon or nitrogen) during powder handling, compaction, and sintering processes to prevent oxidation of the high purity refractory metal powders, enabling maintenance of ultra-low oxygen content (below 100 ppm) throughout manufacturing
Solution Approach 2:
The patent controls oxygen content by adjusting sintering temperature, holding time, and gas atmosphere composition parameters, achieving optimal balance between density consolidation and oxygen pickup prevention through precise parameter optimization
3Adaptability or versatility
If powder metallurgy method is used to manufacture sputtering targets, then manufacturing flexibility is improved, but achieving random crystallographic texture without thermomechanical processing is difficult
Solution Approach 1:
The patent applies local quality by creating a controlled particle size distribution within the powder feedstock, using a mixture of fine and coarse particles that pack and sinter in a manner that promotes random grain orientation and uniform texture throughout the target body
Solution Approach 2:
The patent achieves random crystallographic texture by optimizing sintering temperature and holding time parameters, allowing complete grain recrystallization and random orientation development without the need for subsequent thermomechanical processing
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
This approach results in sputtering targets with uniform crystallographic texture and high purity, capable of withstanding routine stresses and enabling uniform thin film deposition across large substrates, reducing oxygen content and energy consumption, and extending target life by avoiding texture variations and premature wear.
Implementation Method 1
consolidating high purity refractory metal powders, such as tantalum, with controlled oxygen content and particle size distribution, using techniques like hot isostatic pressing
Implementation Method 2
scavenging metals to achieve a random crystallographic texture without thermomechanical processing, ensuring the target body's density and strength
Implementation Method 3
Sputtering processes are employed to deposit thin films onto substrates to manufacture any of a variety of devices. Sputtering processes typically involve bombarding a solid sputtering target body with energized particles to eject atoms from the target body
Data Source
Figure 1A
Figure 1B~1C
Figure 2A1~2A2
AI summary
A method for making a sputtering target including steps of encapsulating and hot isostaticallly pressing at least one mass of metal powder (e.g., tantalum), having a particle size ranging from about 10 to about 1000 µm, with at least about 10 percent by weight of particles having a particle size greater than about 150 µm (for example, about 29 to about 56 percent (e.g., about 35 to about 47 percent) by weight of the particles in the at least one mass of metal powder having a particle size that is larger than 150 microns, but below about 250 µm), for defining at least a portion of a sputtering target body, having an essentially theoretical random and substantially uniform crystallographic texture.