Termination Bonding for High-Temperature Capacitors
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Solution Overview
Problem
Traditional methodologies for producing lead type multilayer capacitors require numerous production steps and are not suitable for high-temperature environments due to the use of low-melting-point solders, which are also being phased out in favor of lead-free alternatives.
Innovation Solution
A methodology where partially completed capacitors are mounted in a lead frame with conductive termination paste applied, and then fired to concurrently terminate and bond the components to the leads, significantly reducing the number of manufacturing steps and enabling operation in higher temperature environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional soldering methodology is used to secure capacitor chips to lead frames, then the components can be assembled, but the melting point temperature is limited and production steps are numerous
Solution Approach 1:
The patent combines multiple separate production steps into a single integrated process. Specifically, it merges the capacitor chip assembly, termination application, and lead frame attachment into one concurrent firing operation. The capacitor body, termination material, and lead frame are assembled together and fired simultaneously at high temperature (above the melting point of the attachment material), eliminating the need for separate soldering steps and enabling high-temperature operation.
Solution Approach 2:
The patent changes the temperature parameter from traditional low-temperature soldering to high-temperature firing. By using attachment materials with high melting points (such as eutectic glass or ceramic-based materials) and firing at temperatures exceeding 800°C, the process achieves both high-temperature operational capability and simplified production. This parameter change fundamentally transforms the attachment mechanism from soldering to direct fusion bonding.
2Ease of manufacture
If low-melting-point solder is used to attach capacitor chips, then assembly is achieved, but the components cannot operate in high-temperature environments
Solution Approach 1:
The patent integrates the attachment material selection with the capacitor body material, using the same high-temperature resistant ceramic or glass-based material for both. This merging ensures that the attachment process can withstand high temperatures and that the bonded joint maintains integrity in high-temperature operating environments, thereby improving reliability without sacrificing ease of manufacture.
Solution Approach 2:
The patent employs composite materials consisting of ceramic powders, glass frits, and metal oxides in the attachment material formulation. These composite materials exhibit high-temperature resistance, chemical stability, and strong bonding characteristics. The combination of different materials provides both ease of assembly through controlled firing and reliability in high-temperature operation, resolving the contradiction between manufacturability and operational reliability.
3Manufacturing precision
If multiple separate production steps are used to complete capacitor manufacturing, then each step can be optimized, but manufacturing cost and complexity increase significantly
Solution Approach 1:
The patent merges multiple production steps into a single integrated firing process. The capacitor body formation, termination material application, and lead frame attachment are all accomplished concurrently during one high-temperature firing cycle. This consolidation reduces the number of production steps while maintaining manufacturing precision through controlled atmosphere and temperature profiles, thereby reducing complexity and cost.
Solution Approach 2:
The patent performs preliminary preparation of all components (capacitor body, termination material, and lead frame) before the final integrated firing step. The termination material is pre-applied to the capacitor body, and all components are pre-positioned in the lead frame, allowing the subsequent firing process to complete all bonding operations simultaneously. This preliminary action enables process integration without sacrificing control over each individual step.
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
This approach reduces production costs and complexity while enabling the capacitors to function effectively in higher temperature environments, improving thermal performance and reliability.
Implementation Method 1
firing the assembled lead frame and at least one electrical component, so that such electrical component is terminated while leads of the lead frame are secured thereto
Data Source
AI summary
Disclosed are methodologies for producing lead type electrical components. Components are placed in a lead frame with termination paste applied to selected portions of the component. Upon firing of the assembled lead frame and electrical components, the electrical components are concurrently terminated, and provided with strongly secured leads.