Fuse Element Crystallinity Control for Crack Suppression
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Solution Overview
Problem
High melting point metal layers formed by thin-film methods, such as plating or vapor deposition, have low crystallinity and mechanical strength, leading to cracks during deformation and increased conductor resistance, which impede high current ratings and desired blowout properties in fuse elements.
Innovation Solution
A fuse element with a low melting point metal layer and a high melting point metal layer, where the high melting point metal layer has a full width at half maximum of 0.15 degrees or less in its X-ray diffraction spectrum, and is heat-treated at a temperature between 120°C and the melting point of the low melting point metal to improve crystallinity and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a high melting point metal layer is formed by thin-film methods (plating, vapor deposition), then the fuse element can be manufactured with low melting point metal properties, but the high melting point metal layer has low crystallinity and mechanical strength, leading to cracks during deformation and increased conductor resistance
Solution Approach 1:
The invention changes the crystalline structure parameter of the high melting point metal layer by controlling the crystal orientation to have <100> direction perpendicular to the layer surface. This parameter change increases the mechanical strength and ductility of the thin-film layer, preventing cracks during deformation while maintaining the benefits of thin-film manufacturing methods.
Solution Approach 2:
The invention creates a composite structure with low melting point metal layer and high melting point metal layer, where the high melting point layer has optimized crystalline structure. This composite material approach combines the manufacturability of thin-film processes with the mechanical strength of properly oriented crystalline structures.
2Manufacturing precision
If the high melting point metal layer is made thinner to reduce resistance, then manufacturing becomes easier, but mechanical strength and crack resistance deteriorate
Solution Approach 1:
By changing the crystal orientation parameter to <100> direction, the invention improves the mechanical properties of the thin film, allowing it to maintain high reliability and crack resistance even at thin dimensions. This enables the use of thinner layers without sacrificing structural integrity.
3Strength
If the high melting point metal layer is made thicker to improve mechanical strength, then crack resistance improves, but conductor resistance increases and current rating capability deteriorates
Solution Approach 1:
The invention changes the crystal orientation parameter to <100> direction, which fundamentally improves the mechanical strength per unit thickness. This allows achieving high mechanical strength with thinner layers, thereby reducing conductor resistance while maintaining crack resistance.
4Ease of manufacture
If conventional thin-film forming methods are used for high melting point metal layer, then manufacturing is simplified, but blowout properties fluctuate due to cracks and increased resistance
Solution Approach 1:
The invention introduces crystal orientation control as an additional parameter in the manufacturing process. By controlling the high melting point metal layer to have <100> crystal orientation perpendicular to the surface, it prevents crack formation and maintains consistent electrical properties, ensuring reliable and consistent blowout characteristics.
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 improved crystallinity and mechanical strength of the high melting point metal layer suppress cracks and reduce conductor resistance, ensuring stable current ratings and consistent blowout properties.
Implementation Method 1
heating the high melting point metal layer to a temperature of at least 120° C. and at most a melting point of the low melting point metal
Implementation Method 2
at least one peak among peaks in an X-ray diffraction spectrum (2θ) of a surface of the high melting point metal layer having a full width at half maximum of 0.15 degrees or less
Data Source
AI summary
A fuse element as well as a fuse device and protective device using the same which are capable of suppressing generation of defects such as cracks in a high melting point metal layer, maintaining good conduction, and maintaining blowout properties. The fuse element includes a laminated low melting point metal layer and high melting point metal layer and at least one peak among peaks in an X-ray diffraction spectrum (2θ) of a surface of the high melting point metal layer has a full width at half maximum of 0.15 degrees or less.