Cylindrical Sputtering Target Joining Strength
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Solution Overview
Problem
Cylindrical sputtering targets face challenges with insufficient joining performance between the sputtering target member and the substrate due to thermal expansion differences, leading to delamination and cracking during sputtering.
Innovation Solution
Increasing the surface roughness of the sputtering target member on the joining material side, with specific roughness values (Rz and Ra) correlated to the joining material's thickness and thermal expansion coefficient, enhances the anchoring effect and maintains contact despite thermal contraction, thereby improving the joining strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a joining material is used to join the cylindrical sputtering target member and the cylindrical substrate, then the joining performance is improved, but the joining material contracts during cooling and creates gaps that reduce joining strength
Solution Approach 1:
The invention changes the surface roughness parameter of the cylindrical sputtering target member to be within a specific range (0.1μm to 10μm). This parameter change allows the surface to maintain adequate contact with the joining material while accommodating the thermal contraction that occurs during cooling, thereby preventing gap formation and maintaining joining reliability without sacrificing strength.
2Strength
If the surface roughness is increased to improve anchoring effect, then the joining strength is enhanced, but the surface quality deteriorates
Solution Approach 1:
The invention optimizes the surface roughness parameter to a specific range (0.1μm to 10μm) that balances two competing requirements: providing sufficient anchoring effect for strong joining while maintaining acceptable surface quality. This controlled parameter change ensures both joining strength and surface quality are satisfied simultaneously.
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 enhanced surface roughness ensures a stronger bond between the sputtering target member and the substrate, reducing the likelihood of delamination and cracking, and alleviates stress caused by thermal expansion differences during sputtering.
Implementation Method 1
the joining material has a thickness, estimated from a difference between an inner diameter of the cylindrical sputtering target member and an outer diameter of the cylindrical substrate, of d (μm), the joining material has a coefficient of thermal expansion of α1 (μm/μmK), and a melting point of the joining material and room temperature have a difference of ΔT (K)
Data Source
AI summary
A cylindrical sputtering target includes a cylindrical substrate and a cylindrical sputtering target member joined together with a joining material. Where the joining material has a thickness of d (μm), the joining material has a coefficient of thermal expansion of α1 (μm/μmK), and a melting point of the joining material and room temperature have a difference of ΔT (K), a surface of the cylindrical sputtering target member on the side of the joining material has a value of ten-point average roughness (Rz) fulfilling:d (μm)×α1 (μm/μmK)×ΔT (K)≤Rz (μm).