External Electrode Layer Structure for Crack-Resistant Mounting
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Solution Overview
Problem
Electronic components face cracking issues due to stress concentration at the end edges of external electrodes during solder-mounting, leading to potential failures in reliability and durability.
Innovation Solution
The electronic component design incorporates a conductive resin layer and sintered metal layer configuration, where the conductive resin layer covers the end edges of the sintered metal layer and is strategically positioned to distribute stress, preventing concentration at the electrode edges, and includes a plating layer for enhanced bonding and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the external electrode is disposed on the element body with a sintered metal layer, then electrical conductivity is improved, but stress concentration occurs at the end edge of the external electrode causing cracks in the element body
Solution Approach 1:
The patent applies composite materials by combining sintered metal layer with conductive resin layer and plating layer to form the external electrode. The sintered metal layer provides electrical conductivity, while the conductive resin layer reduces stress concentration at the end edge. This composite structure resolves the contradiction between maintaining electrical conductivity and preventing stress-induced cracks.
Solution Approach 2:
The patent applies local quality by having different layers serve different functions at different locations of the external electrode. The sintered metal layer is positioned where electrical conductivity is needed, while the conductive resin layer is positioned at the end edge where stress concentration occurs. This localized functional differentiation resolves the contradiction between electrical conductivity and stress resistance.
2Ease of manufacture
If the external electrode structure is simplified, then manufacturing ease is improved, but stress distribution is insufficient leading to crack occurrence
Solution Approach 1:
The patent applies segmentation by dividing the external electrode into multiple functional layers: sintered metal layer, conductive resin layer, and plating layer. Each layer serves a specific function - the sintered metal layer for conductivity, the conductive resin layer for stress distribution, and the plating layer for protection. This segmented structure achieves both manufacturing feasibility and crack suppression.
Solution Approach 2:
The patent applies preliminary action by pre-positioning the conductive resin layer and plating layer on the sintered metal layer before the electrode is mounted. This preliminary preparation ensures that the stress-distributing and protective functions are already in place before the electrode undergoes mounting stress, preventing crack occurrence from the outset.
3Strength
If the conductive resin layer is added to the external electrode, then stress concentration is reduced, but device complexity increases
Solution Approach 1:
The patent applies merging by combining multiple functions into the external electrode structure. The conductive resin layer serves dual purposes: it acts as a stress-distributing material to prevent cracks while also maintaining electrical conductivity. The plating layer simultaneously provides protection and enhances conductivity. This merging of functions achieves stress distribution without proportionally increasing device complexity.
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 configuration effectively suppresses the occurrence of cracks in the element body, enhances mounting strength, and improves moisture resistance, while maintaining reliable electrical connectivity.
Implementation Method 1
the conductive resin layer covers the end edges of the sintered metal layer and is strategically positioned to distribute stress, preventing concentration at the electrode edges
Implementation Method 2
The first electrode portion includes a sintered metal layer, a conductive resin layer formed on the sintered metal layer, and a plating layer formed on the conductive resin layer
Implementation Method 3
The first electrode portion includes a sintered metal layer, a conductive resin layer formed on the sintered metal layer
Data Source
AI summary
An element body includes a principal surface arranged to constitute a mounting surface and a first side surface adjacent to the principal surface. An external electrode includes a first electrode portion disposed on the principal surface and a second electrode portion disposed on the first side surface. The first electrode portion includes a sintered metal layer, a conductive resin layer formed on the sintered metal layer, and a plating layer formed on the conductive resin layer. The second electrode portion includes a first region and a second region. The first region includes a sintered metal layer and a plating layer formed on the sintered metal layer. The second region includes a sintered metal layer, a conductive resin layer formed on the sintered metal layer, and a plating layer formed on the conductive resin layer. The second region is located closer to the principal surface than the first region.