Asymmetric Semiconductor Package Mounting for LED Alignment
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Solution Overview
Problem
In compact semiconductor packages, the lack of solder creep along side faces during soldering leads to misalignment and height differences, making accurate mounting challenging, especially affecting light emission direction and heat dissipation.
Innovation Solution
A light emitting device design featuring a semiconductor package with a first and second conduction member of varying sizes, connected to corresponding narrow and wide parts of the mounting board's wiring components, with recesses and insulator layers to manage solder distribution and ensure accurate horizontal mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a compact semiconductor package is used to reduce size and weight, then the package becomes smaller and lighter, but solder creep along side faces during soldering is reduced, causing misalignment and height differences
Solution Approach 1:
The invention introduces asymmetric structures including a convex portion on the semiconductor package and a corresponding concave portion on the mounting board, along with asymmetric wiring patterns of different lengths. This asymmetry creates directional control for solder flow, ensuring proper alignment and preventing misalignment issues that occur with symmetric, compact designs.
Solution Approach 2:
The convex and concave portions are pre-formed structures that guide solder creep before the actual soldering process completes. By preparing these alignment features in advance, the invention ensures that solder flows to the correct locations, preventing misalignment and height differences in compact packages.
2Volume of moving object
If the semiconductor package size is reduced to achieve compact design, then the package becomes more compact, but accurate mounting becomes difficult due to lack of solder creep
Solution Approach 1:
The asymmetric convex and concave portions, combined with wiring patterns of different lengths, create a directional guide for solder flow. This allows compact packages to be accurately mounted by controlling where solder creeps during the soldering process, rather than relying on solder creep along all side faces.
Solution Approach 2:
Instead of requiring uniform solder creep along all sides of the package, the invention creates specific local features (convex and concave portions) that concentrate and control solder flow in critical areas. This local quality approach ensures accurate mounting even when the overall package size is reduced.
3Manufacturing precision
If wiring patterns with concave shapes are used to absorb solder variance, then solder distribution is improved, but solder creep along side faces is still insufficient in compact packages
Solution Approach 1:
The invention enhances the asymmetric design by creating wiring patterns of deliberately different lengths on opposite sides. This asymmetry, combined with the convex-concave portion structures, ensures that solder creep is directed and controlled, making the soldering process more reliable even in compact packages where natural solder creep is limited.
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 enables high-accuracy mounting of small, lightweight semiconductor packages on a mounting board, preventing misalignment and enhancing heat dissipation while maintaining compact size.
Implementation Method 1
when soldering to the mounting board, as the solder flows
Implementation Method 2
excess solder 73 that has been reflowed at the ends of a mounted part 72 on a mounting board 71 creeps up along the side faces
Data Source
AI summary
[Object] Disclosed is a light emitting device that enables a small and lightweight semiconductor package to be precisely mounted on a packaging substrate. [Means for Solving Problem] A light emitting device being such that a semiconductor package equipped with a first conduction member and a second conduction member, and a mounting board equipped with a first wiring component and a second wiring component that are respectively connected to the first conduction member and the second conduction member by a joining member, the semiconductor package comprises: a light emitting element; a first conduction member, on one side of which the light emitting element is placed; and a second conduction member whose surface area is smaller than that of the first conduction member, the other side of the first conduction member and the second conduction member, on the opposite side from said one side, forms the lower face of the semiconductor package, and the mounting board comprises: a narrow part and a wide part that extends away from the first and second conduction members and is wider than the narrow part, which are formed on the first wiring component and the second wiring component, at least the narrow part is joined to the first conduction member and the second conduction member, and the first wiring component has a recess in its interior.