Multilayer Ceramic Capacitor Mounting Structure with Stress-Absorbing Electrodes
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Solution Overview
Problem
Multilayer ceramic capacitors used in severe environments, such as mobile devices and electronic control units, face issues with crack generation due to stress from circuit boards, which existing technologies fail to adequately address, leading to insufficient crack prevention and connection maintenance.
Innovation Solution
A multilayer-ceramic-capacitor mounting structure featuring external electrodes with a conductive metal and glass component base electrode layer, a thermosetting resin and metal component conductive resin layer, and a plated layer, connected to a copper plate on the circuit board with a predetermined thickness, which absorbs stress and reduces crack generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a multilayer ceramic capacitor is mounted on a circuit board in a severe environment, then it can function in mobile devices or electronic control units, but cracks are generated due to stress from thermal expansion and impact
Solution Approach 1:
The external electrode is constructed as a composite structure with three distinct layers: a base electrode layer providing structural foundation, a conductive resin layer containing rubber particles that provides elasticity and stress absorption, and a plated layer providing conductivity and connection. This composite structure enables the electrode to simultaneously maintain structural integrity and absorb thermal stress through the elastic deformation of the rubber-containing conductive resin layer.
2Ease of manufacture
If the external electrode structure is simplified, then manufacturing becomes easier, but stress from the circuit board is not sufficiently relaxed leading to crack generation
Solution Approach 1:
The conductive resin layer is strategically positioned between the rigid base electrode layer and the plated layer, creating a localized elastic buffer zone. This layer contains rubber particles that provide localized stress absorption and elastic deformation capability, allowing the electrode structure to relax board stress without requiring complex overall redesign, thus maintaining manufacturing simplicity while improving reliability.
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 proposed structure significantly reduces or prevents crack generation in multilayer ceramic capacitors by effectively absorbing stress through the increased elasticity of the external electrodes and copper plate, enhancing their durability and connection reliability.
Implementation Method 1
a conductive resin layer disposed on a surface of the base electrode layer and including a thermosetting resin and a metal component
Implementation Method 2
connected to a copper plate on the circuit board with a predetermined thickness, which absorbs stress and reduces crack generation
Data Source
AI summary
A multilayer-ceramic-capacitor mounting structure includes a circuit board and a multilayer ceramic capacitor. First and second external electrodes include first and second conductive resin layers on surfaces of first and second base electrode layers, respectively. The circuit board includes a copper plate on a surface of a core, disposed as a wiring pattern, and including a predetermined thickness, and signal electrodes disposed on a surface of the copper plate. The first and second external electrodes are each electrically connected to the signal electrodes of the copper plate.