Terminal Electrode Conductor Depression for Solder Wetting Control
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Solution Overview
Problem
Existing electronic components face issues with solder wetting during mounting, leading to tombstoning and reduced bonding strength due to the need for larger solder areas and increased solder amounts, which can result in uneven solder distribution and poor attachment.
Innovation Solution
The electronic component features terminal electrodes with a depression on the conductor, positioned between protrusions, which elongates the solder wetting distance and encourages solder accumulation in the depression, reducing unwanted wetting and ensuring bonding strength by controlling solder distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the terminal electrodes extend in the longitudinal direction with larger length, then the electrical connection is improved, but the land area required increases leading to excessive solder wetting
Solution Approach 1:
The conductor is designed with non-uniform cross-sectional area, featuring a larger area at the base and smaller area at the tip. This local variation in geometry creates a progressive wetting path that controls solder flow, allowing reliable electrical connection while preventing excessive solder wetting that causes tombstoning.
Solution Approach 2:
The conductor cross-sectional area varies along its length, introducing a dimensional gradient that controls solder wetting behavior. This gradual change in cross-sectional area creates a controlled wetting path that prevents sudden solder spread while maintaining electrical connectivity.
2Reliability
If larger lands are used to accommodate the terminal electrodes, then the electrical connection is improved, but the solder amount required increases causing tombstoning
Solution Approach 1:
The conductor's cross-sectional area is optimized locally at different positions - larger at the base for strong bonding and smaller at the tip to limit solder wetting. This local quality variation ensures adequate bonding strength while controlling solder consumption and preventing tombstoning.
3Ease of manufacture
If the conductor has uniform cross-sectional area, then the manufacturing is simplified, but the solder distribution becomes uneven causing poor attachment
Solution Approach 1:
The conductor is designed with deliberately non-uniform cross-sectional area, where the base has a larger area for solder accumulation and the tip has a smaller area to prevent excessive wetting. This local quality variation ensures uniform solder distribution and reliable attachment, with the added benefit that such conductors can be manufactured using standard ceramic processing techniques.
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 solder wetting beyond the depression, preventing tombstoning and ensuring reliable bonding strength between the terminal electrodes and the electronic device.
Implementation Method 1
the solder needs to pass over the protrusion before reaching the depression... the distance at which the solder wets over the conductor is long... the solder tends to accumulate in the depression, and a solder pool is formed
Data Source
AI summary
An element body of a rectangular parallelepiped shape has a length in a width direction larger than a length in a height direction and has a length in a longitudinal direction larger than the length in the width direction. A terminal electrode is disposed at an end of the element body in the width direction and extends in the longitudinal direction. The element body includes a pair of principle surfaces opposing each other in the height direction, a pair of end surfaces opposing each other in the longitudinal direction, and a pair of side surfaces opposing each other in the width direction. The terminal electrode includes a conductor disposed on the side surface. The conductor includes a depression having a length in the longitudinal direction larger than a length in the height direction.