Multi-Layer Ceramic Capacitor Electrode Gap for Reflow Stress Relief
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Solution Overview
Problem
High-voltage multi-layer ceramic capacitors face issues with creeping discharge and boundary separation between the ceramic body and external material during reflow soldering, leading to potential defects due to stress concentration at the external electrode tips.
Innovation Solution
A multi-layer ceramic electronic component design featuring a gap between the external electrode and the main surface of the ceramic body, covered with an external material, which reduces stress concentration and prevents separation by distributing stress vertically, thereby stabilizing the bond between the ceramic body and external material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the external electrode is in direct contact with the main surface of the ceramic body, then the bonding area is maximized, but stress concentration occurs at the external electrode tip during reflow soldering causing boundary separation between the ceramic body and external material
Solution Approach 1:
The patent extracts the harmful tip portion of the external electrode by forming a recess that separates the electrode tip from the main surface of the ceramic body. This removes the stress concentration point while preserving the bonding area through the electrode's contact with the ceramic body in the recess region.
Solution Approach 2:
The patent provides beforehand cushioning by forming a recess structure that anticipates and compensates for the stress generated during reflow soldering. The recess acts as a stress-absorbing feature that prevents boundary separation before it can occur.
2Reliability
If the external electrode covers a large portion of the main surface, then electrical connectivity is improved, but the risk of creeping discharge increases along the surface of the ceramic body
Solution Approach 1:
The patent extracts the electrode tip from direct contact with the main surface by forming a recess, thereby removing the pathway for creeping discharge while maintaining electrical connectivity through the electrode's connection to the ceramic body at the recess location.
3Object-affected harmful factors
If the external material is molded directly over the ceramic body surface, then protection is provided, but separation occurs during reflow soldering due to thermal stress
Solution Approach 1:
The patent provides beforehand cushioning by forming a recess structure that anticipates thermal stress during reflow soldering. The recess creates a stress-absorbing configuration that prevents boundary separation between the ceramic body and external material while maintaining protection.
Solution Approach 2:
The patent changes the geometric parameter of the electrode-ceramic interface by forming a recess, thereby altering the stress distribution pattern. This parameter change transforms the rigid contact into a stress-absorbing configuration that maintains bond stability under thermal stress.
Data Source
AI summary
A multi-layer ceramic electronic component includes a multi-layer ceramic electronic component main body including a multi-layer body including stacked ceramic layers, stacked internal electrode layers, first and second main surfaces, first and second side surfaces, and first and second end surfaces, first and second external electrodes respectively on sides where the first and second end surfaces are located, and first and second metallic terminals respectively connected to the first and second external electrodes. The multi-layer ceramic electronic component main body and at least portion of the first and second metallic terminals are covered with an external material. The second main surface is connected to the metallic terminals. The first and second external electrodes cover a portion of the second main surface. A gap is provided between the multi-layer body and tips of the first and second external electrodes. The external material is in the gap.