Thin-Coated Sputter Trap for Particle Capture Under Thermal Stress
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Solution Overview
Problem
In sputtering processes, particles formed during deposition can contaminate substrates by redepositing onto the thin film, and existing sputter traps may flake off due to thermal stress, disrupting the film's properties.
Innovation Solution
A sputter trap with a surface roughness greater than the back surface, featuring a thin, high-purity metallic coating layer formed by cold spraying metallic particles onto a textured surface, which enhances adhesion and reduces impurities, thereby improving particle retention and film uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sputter trap is used to capture particles during deposition, then particle capture capability is improved, but the trap may flake off during thermal stress and disrupt the thin film
Solution Approach 1:
The sputter trap comprises a multi-layer composite structure including a substrate layer and a coating layer with different thermal expansion coefficients. This composite structure absorbs thermal stress through inter-layer deformation, preventing the trap from flaking off during thermal cycles while maintaining particle capture functionality.
Solution Approach 2:
The coating layer is designed with specific material parameters including controlled thickness (0.5-5 micrometers), porosity (30-70%), and thermal expansion coefficient matching. These parameter optimizations enable the coating to withstand thermal stress while maintaining adhesion to the substrate, resolving the flaking issue.
2Reliability
If a thick coating layer is applied to the sputter trap, then particle retention is improved, but the coating may flake off during thermal stress
Solution Approach 1:
The coating layer thickness is optimized to 0.5-5 micrometers, which is sufficient to trap particles effectively while thin enough to prevent flaking during thermal stress. The porosity is controlled at 30-70% to balance particle retention with stress resistance, creating a coating that adheres strongly to the substrate.
3Reliability
If the sputter trap surface is roughened to capture particles, then particle capture is improved, but impurities may be present on the surface
Solution Approach 1:
The sputter trap uses a composite structure where the substrate layer provides the roughened surface for particle capture, while the separate coating layer acts as a barrier that filters and removes impurities. This layered composite allows the rough surface to retain particles effectively while the coating maintains surface purity.
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 captures and retains particles, reducing the likelihood of contamination and maintaining the surface texture, leading to improved film quality and reduced impurities on the sputter trap.
Implementation Method 1
cold spraying metallic particles onto a textured surface
Implementation Method 2
A sputter trap or particle trap can be included on a sputtering target to capture particles formed during a deposition process
Data Source
AI summary
An aluminum or copper alloy sputtering chamber includes a front surface, a back surface opposite the front surface, and a sputter trap formed on at least a portion of the front surface A coating of titanium particles is formed on the sputter trap.