Cr-Si Sputtering Target Composition for Crack-Resistant Thin Films
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Solution Overview
Problem
Existing Cr—Si sputtering targets have low mechanical strength, making them prone to cracking during processing and film formation, which limits their usability and productivity in industrial thin film production.
Innovation Solution
A Cr—Si sintered body with a stoichiometric CrSi2 phase and a Si phase, produced using rapidly quenched alloy powder, achieving a high relative density and controlled crystal grain sizes, and containing minimal impurities, is used to create a sputtering target with enhanced mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a sputtering target containing silicide is used, then high resistivity stability is achieved, but mechanical strength is insufficient causing cracking during processing and discharging
Solution Approach 1:
The patent applies composite materials by creating a sintered body composed of two distinct phases: a chromium silicide (CrSi2) phase providing high resistivity stability and a silicon (Si) phase providing mechanical strength. This composite structure allows the material to simultaneously achieve both electrical stability and mechanical integrity, resolving the contradiction between resistivity stability and mechanical strength
Solution Approach 2:
The patent applies local quality by creating regions with different phases throughout the sintered body. The chromium silicide phase is distributed throughout the matrix, providing localized areas of high resistivity stability, while the silicon phase provides structural support and mechanical strength. This spatial distribution of different properties withing the material allows simultaneous achievement of both requirements
2Strength
If thermal spraying method is used to produce sputtering target, then mechanical strength is improved, but mechanical strength is not sufficiently increased in portions with low Cr content
Solution Approach 1:
The patent applies parameter changes by controlling the composition ratio of CrSi2 phase to Si phase, ensuring Cr content is 20-40 wt% and Si content is 60-80 wt%. This compositional parameter optimization ensures uniform mechanical strength throughout the sintered body, preventing the non-uniformity that occurs in thermal spraying methods where low Cr content regions have insufficient strength
3Manufacturing precision
If melting method is used to produce composition, then fine eutectic structure is achieved, but proportion of eutectic structure is low resulting in insufficient mechanical strength
Solution Approach 1:
The patent applies parameter changes by controlling the composition within specific ranges (CrSi2 phase 20-40 wt%, Si phase 60-80 wt%) and controlling sintering parameters (temperature 1000-1500°C, pressure 10-100 MPa, time 1-10 hours). These parameter optimizations ensure that the sintered body achieves both fine microstructure and high mechanical strength, overcoming the limitation of melting methods where large primary crystals form and reduce strength
4Volume of stationary object
If size of composition is increased, then larger sputtering target is produced, but control of crystalline microstructure becomes difficult due to cooling rate differences
Solution Approach 1:
The patent applies preliminary action by using pre-prepared powder materials with controlled composition and particle size (average 1-100 μm) before sintering. This preliminary preparation ensures that even when producing large sputtering targets, the starting material has uniform properties that lead to consistent crystalline microstructure throughout the final product, overcoming the cooling rate variability issue in melting methods
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 resulting sputtering target exhibits high flexural strength, reducing the likelihood of cracking during sputtering and improving film formation productivity by maintaining mechanical integrity and resistivity stability.
Implementation Method 1
a Cr—Si sintered body containing chromium (Cr) and silicon (Si), in which a crystal structure determined by X-ray diffraction is constituted by a chromium silicide (CrSi2) and silicon (Si)
Implementation Method 2
a crystal structure determined by X-ray diffraction is constituted by a chromium silicide (CrSi2) and silicon (Si)
Implementation Method 3
a Cr—Si sintered body having high mechanical strength is obtained by using a rapidly quenched alloy powder such as a gas atomized powder
Data Source
AI summary
A Cr—Si sintered body contains Cr and Si. The Cr—Si sintered body contains a crystalline CrSi2 phase and a crystalline Si phase. A content of the Si phase in the Cr—Si sintered body is 40% by mass or more. A relative density of the Cr—Si sintered body relative to a true density of the Cr—Si sintered body is 95% or more. The CrSi2 phase has an average crystal grain size of 40 μm or less, and the Si phase has an average crystal grain size of 30 μm or less. A total content of impurities in the Cr—Si sintered body is 200 ppm by mass or less, and the impurities are composed of at least one element selected from the group consisting of Mn, Fe, Mg, Ca, Sr, and Ba.