Multilayer Ceramic Capacitor Electrode Segmentation for Solder Wetting
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Solution Overview
Problem
Multilayer ceramic capacitors with two-face type external electrodes face challenges in soldering due to uneven solder wetting and three-dimensional deflection during installation, leading to potential separation and cracking issues when made thinner.
Innovation Solution
The design incorporates auxiliary planar parts on the external electrodes with specific dimensions and configurations to distribute solder wetting uniformly and reduce deflection, ensuring consistent wetting and minimizing structural stress during soldering and installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the multilayer ceramic capacitor is made thinner, then the capacitor can be integrated into thinner electronic devices, but the capacitor body may crack due to three-dimensional deflection during installation
Solution Approach 1:
The external electrode is segmented into multiple functional parts: a longitudinal part, a lateral part, and an intermediate part connecting them. This segmentation allows each part to perform its specific function - the longitudinal and lateral parts form the L-shaped structure for electrical connection, while the intermediate part specifically addresses deflection by providing structural support during installation
Solution Approach 2:
The external electrode structure extends into three dimensions with the intermediate part projecting from the longitudinal part toward the lateral part. This three-dimensional configuration provides additional structural support in the thickness direction, preventing the thin capacitor body from deflecting and cracking during installation while maintaining the L-shaped cross-section for proper electrical connection
2Ease of operation
If the external electrodes are of the two-face type with L-shaped longitudinal cross-section, then the capacitor can be installed on circuit boards, but uneven solder wetting occurs leading to separation and rise phenomena
Solution Approach 1:
Different parts of the external electrode are given different properties and functions: the longitudinal part provides the main electrical connection path, the lateral part enables mounting on the circuit board, and the intermediate part with specific dimensions controls solder flow distribution. This local differentiation ensures that each region performs its intended function optimally, including uniform solder wetting across the electrode surface
3Ease of operation
If the longitudinal part and lateral part form a continuous L-shaped structure, then the external electrode can be mounted on circuit boards, but it is difficult to reduce three-dimensional deflection of the capacitor body
Solution Approach 1:
The external electrode is divided into distinct segments - the longitudinal part, the lateral part, and the intermediate part - allowing each segment to be optimized for its specific function. The intermediate part specifically addresses deflection control while the other parts maintain their mounting and electrical connection functions
Solution Approach 2:
By adding the intermediate part that projects in the thickness direction, the electrode structure gains additional dimensional support. This three-dimensional configuration provides rigidity against deflection while preserving the L-shaped footprint needed for circuit board mounting
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 design enhances the uniformity of solder wetting and reduces three-dimensional deflection, preventing separation and cracking, even when the capacitors are made thinner, thereby improving the reliability and stability of the multilayer ceramic capacitors.
Implementation Method 1
The cream solder applied on the respective conductor pads melts while in contact with the lateral parts of the external electrodes, so some of the molten solder flows into the space between each conductor pad and the lateral part of each external electrode
Data Source
AI summary
In an exemplary embodiment, each of external electrodes 12 of a multilayer ceramic capacitor 10 continuously has a first planar part 12a present on each end face of a capacitor body 11 in a first direction d1, a second planar part 12b present on one end face of the capacitor body 11 in a third direction d3, and auxiliary planar parts 12c present on both end faces of the capacitor body 11 in a second direction d2. A maximum third-direction dimension D3 [12c] of each of the auxiliary planar parts 12c is smaller than a third-direction dimension D3 [12a] of the first planar part 12a, while a first-direction dimension D1 [12c] of each of the auxiliary planar parts 12c is smaller than a first-direction dimension D1 [12b] of the second planar part 12b.