Tantalum Sputtering Target Composition for Plasma Stability
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Solution Overview
Problem
Conventional high purity tantalum sputtering targets fail to achieve a uniform and fine structure, leading to unstable plasma and film non-uniformity, particularly when attempting to form complex shapes or barrier films in the electronics field.
Innovation Solution
A tantalum sputtering target with a specific composition of 1-100 mass ppm tungsten, and optionally 0-150 mass ppm molybdenum and niobium, ensuring a purity of 99.998% or higher, which stabilizes plasma and enhances film uniformity by maintaining a uniform and fine crystal grain size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional high purity tantalum sputtering targets are used, then the material purity is high, but the crystal grain structure is coarse and non-uniform, leading to unstable plasma and poor film evenness
Solution Approach 1:
The patent changes the chemical composition parameters by adding specific elements (W: 1-100 ppm, Mo: 0-150 ppm, Nb: 0-150 ppm) to the high purity tantalum base material. This compositional parameter change induces recrystallization that produces a fine and uniform crystal grain structure, thereby improving both plasma stability and film evenness simultaneously
Solution Approach 2:
The patent creates a composite material system by incorporating trace amounts of tungsten, molybdenum, and/or niobium into the high purity tantalum matrix. This composite approach leverages the beneficial effects of alloying elements on crystal grain refinement while maintaining the high purity characteristics of tantalum, resolving the contradiction between material purity and structural uniformity
2Manufacturing precision
If conventional tantalum targets are used, then the material is simple and pure, but the crystal grain size is large (50 mm or more), resulting in poor deposition uniformity
Solution Approach 1:
The patent applies precise parameter changes by controlling the addition of alloying elements within specific ranges (W: 1-100 ppm, Mo: 0-150 ppm, Nb: 0-150 ppm). These controlled parameter changes induce recrystallization that reduces crystal grain size from 50 mm to 100 μm or less, achieving fine and uniform deposition without excessive material complexity
Solution Approach 2:
The patent introduces local quality changes by adding specific elements at controlled concentrations to achieve localized crystal grain refinement. The added elements (W, Mo, Nb) create local regions that promote uniform nucleation and growth, resulting in overall fine and uniform crystal structure throughout the target material
3Reliability
If trace amounts of elements are added to stabilize plasma, then plasma stability improves, but the content adjustment becomes difficult and variation increases
Solution Approach 1:
The patent establishes specific parameter ranges for additive elements (W: 1-100 ppm, Mo: 0-150 ppm, Nb: 0-150 ppm) that optimize plasma stability while remaining achievable with conventional manufacturing processes. These parameter specifications balance performance requirements with manufacturing feasibility, reducing content variation
Solution Approach 2:
The patent promotes homogeneity by selecting alloying elements (W, Mo, Nb) that are compatible with the tantalum matrix and can be uniformly distributed at trace concentrations. The recrystallization process further enhances homogeneity by creating a fine and uniform crystal grain structure that evenly distributes the additive elements throughout the material
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 stable plasma and superior film evenness, shortening the burn-in time and improving the quality of sputter deposition, making it suitable for complex shape formation and circuit fabrication in the electronics field.
Implementation Method 1
the sputtering method for forming a film from materials such as metal or ceramics has been used in numerous fields
Implementation Method 2
an ingot or billet formed by performing electron beam melting and casting to a tantalum raw material
Implementation Method 3
the hot forging performed to the ingot or billet will destroy the cast structure, disperse or eliminate the pores
Implementation Method 4
by further annealing this, recrystallization will occur, and the densification and strength of the structure can be improved
Implementation Method 5
recrystallization will occur, and the densification and strength of the structure can be improved to a certain degree
Data Source
AI summary
Provided is a tantalum sputtering target containing 1 mass ppm or more and 100 mass ppm or less of tungsten as an essential component, and having a purity of 99.998% or more excluding tungsten and gas components. Additionally provided is a tantalum sputtering target according to according to the above further containing 0 to 100 mass ppm of molybdenum and/or niobium, excluding 0 mass ppm thereof, wherein the total content of tungsten, molybdenum, and niobium is 1 mass ppm or more and 150 mass ppm or less, and wherein the purity is 99.998% or more excluding tungsten, molybdenum, niobium and gas components. Thereby obtained is a high purity tantalum sputtering target comprising a uniform and fine structure and which enables stable plasma and yields superior film evenness (uniformity).