Fine-Grain Molybdenum Sputtering Target for Low-Particle Deposition
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Solution Overview
Problem
Existing molybdenum sputtering targets with high density and low oxygen content struggle to achieve fine crystal grains, leading to increased particle generation during deposition.
Innovation Solution
A molybdenum sputtering target with an average crystal grain size of less than 10 µm, a relative density of 99.6% or more, and an oxygen content of 100 ppm by mass or less, produced through a refining process involving plastic working and heat treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If hot isostatic pressing (HIP) sintering is performed under high temperature-high pressure conditions to achieve high density, then the density increases, but the crystal grain size grows largely
Solution Approach 1:
The patent applies preliminary action by performing HIP sintering first to achieve high density (99.6% or more), then subsequently applying plastic working (rolling, forging, or extrusion) to refine the crystal grains. This sequential approach allows the density to be established first, then the grain size to be controlled through mechanical deformation and recrystallization processes.
Solution Approach 2:
The patent utilizes parameter changes by controlling the temperature and pressure conditions during plastic working to achieve recrystallization. Specifically, the plastic working is performed at temperatures between room temperature and the melting point of molybdenum, with optimal results achieved through controlled heating that promotes grain refinement while maintaining the high density structure.
2Quantity of substance
If sintering is performed with low oxygen content to reduce impurities, then the oxygen content decreases, but the crystal grain size increases
Solution Approach 1:
The patent applies preliminary action by first achieving low oxygen content through HIP sintering in a controlled atmosphere, then subsequently applying plastic working to refine the grains. The low oxygen content is established before grain refinement, allowing the beneficial low-oxide property to be preserved while grain size is reduced through mechanical processing.
Solution Approach 2:
The patent utilizes parameter changes by performing plastic working at controlled temperatures and strain rates that promote dynamic recrystallization. The temperature is maintained below the melting point but high enough to enable grain boundary migration and refinement, while the applied strain creates new grain structures that are finer than the original sintered state.
3Object-generated harmful factors
If crystal grain size is reduced to less than 10 µm to reduce particle generation, then particle generation decreases, but achieving high density and low oxygen content simultaneously becomes difficult
Solution Approach 1:
The patent applies preliminary action by first achieving the desired high density (99.6% or more) and low oxygen content (100 ppm or less) through HIP sintering, then subsequently applying plastic working to reduce the grain size to less than 10 µm. This sequence ensures that the material properties of high density and low oxygen content are established before grain refinement, preventing degradation of these properties during the grain size reduction process.
Solution Approach 2:
The patent utilizes parameter changes by performing plastic working at controlled temperatures and strain rates that promote grain refinement while maintaining density. The temperature is optimized to enable recrystallization and grain boundary movement without causing excessive grain growth or density reduction, achieving the dual goal of fine grains and high density with low oxygen content.
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 target achieves a reduction in particle generation during deposition, while maintaining high density and low oxygen content, resulting in a sputtering film with improved crystallinity and uniformity.
Implementation Method 1
a refining step comprising a plastic working step of subjecting a molybdenum ingot to plastic working to obtain a plastically worked product, and a heat treatment step of subjecting the plastically worked product to heating treatment
Implementation Method 2
a refining step comprising a plastic working step of subjecting a molybdenum ingot to plastic working to obtain a plastically worked product, and a heat treatment step of subjecting the plastically worked product to heating treatment
Implementation Method 3
a method for producing a sputtering film using a molybdenum sputtering target
Data Source
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AI summary
A molybdenum sputtering target includes molybdenum. The molybdenum sputtering target contains crystal grains having an average crystal grain size of less than 10 µm and has a relative density of 99.6% or more and an oxygen content of 100 ppm by mass or less.