Surface Mount Component Solder Distribution and Terminal Design
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Solution Overview
Problem
Existing surface mount electronic components face challenges with reflow mounting, height reduction, and short-circuiting due to inadequate solder distribution and surface flatness, leading to mounting failures and increased production costs.
Innovation Solution
A surface mount electronic component design featuring a dielectric layer with optimized metal terminals and solder distribution, where the solder cross-sectional area is set within a specific range to prevent short-circuiting, and the use of lead-free solder with a high melting point ensures reliable bonding and heat resistance, while the exterior material provides improved flatness and bonding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a protective coating material is coated on the element, then surface flatness is improved, but mounting failure occurs due to insufficient flatness
Solution Approach 1:
The patent specifies precise dimensional parameters for the metal terminal structure, including the distance from the first main surface to the distal end of the first bonding portion (0.5-2.0 mm) and the cross-sectional area of solder (0.003D-0.02D mm²). These parameter optimizations ensure both sufficient surface flatness for mounting and appropriate solder distribution to prevent short-circuiting, resolving the contradiction between surface quality and mounting reliability.
2Reliability
If the element is accommodated in a case, then mounting reliability is improved, but component height increases
Solution Approach 1:
The patent extracts and eliminates the case structure from the electronic component design. Instead of accommodating the element in a separate case, the invention uses the metal terminal structure with optimized bonding portions and solder distribution to provide both mechanical support and electrical connection, achieving mounting reliability without the additional height imposed by a case.
Solution Approach 2:
The patent merges the functions of the case, metal terminal, and bonding structure into a single integrated metal terminal assembly. The first bonding portion, extending portions, and mounting portion work together as a unified structure that provides both mechanical support (replacing the case function) and electrical connection, thereby eliminating the need for a separate case and reducing overall component height.
3Strength
If the solder amount is increased to ensure bonding, then bonding strength is improved, but short-circuiting occurs due to solder flow
Solution Approach 1:
The patent precisely controls the solder cross-sectional area within the range of 0.003D-0.02D mm² (where D is the element diameter) and positions the distal end of the bonding portion 0.5-2.0 mm from the first main surface. These parameter optimizations ensure sufficient bonding strength while preventing excessive solder from flowing and causing short-circuits between opposing external electrodes.
Solution Approach 2:
The first bonding portion acts as an intermediary structure between the external electrode and the mounting board. By controlling its dimensions and the solder amount within it, the invention mediates between the need for strong bonding and the need to prevent solder overflow, ensuring reliable connection without short-circuiting.
4Temperature
If lead-free solder with high melting point is used, then heat resistance is improved, but bonding difficulty increases
Solution Approach 1:
The patent optimizes the bonding portion geometry, including its cross-sectional area and distance from the element surface, to facilitate proper solder distribution and wetting. These geometric parameter adjustments compensate for the higher melting point of lead-free solder, making the bonding process more controllable and easier to manufacture while maintaining excellent heat resistance.
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
Enables reliable reflow mounting, reduces component height, prevents short-circuiting, and ensures stable bonding and mounting reliability, thereby addressing the limitations of previous designs.
Implementation Method 1
a first metal terminal connected to the first external electrode by solder, a second metal terminal connected to the second external electrode by the solder
Data Source
AI summary
A surface mount electronic component includes an element including a dielectric layer that includes a first main surface and a second main surface, a first external electrode disposed on the first main surface, a second external electrode disposed on the second main surface, a first metal terminal connected to the first external electrode by solder, a second metal terminal connected to the second external electrode by the solder, and an exterior material covering at least a portion of the element, the first and second external electrodes, and the first and second metal terminals. The solder satisfies a relational expression: element diameter D (mm)×about 0.003 mm≤solder cross-sectional area S (mm2)≤element diameter D (mm)×about 0.02 mm.