Dome-Sealed LED Package Layout for Solder Protrusion Control
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Solution Overview
Problem
Existing airtight packages for semiconductor light-emitting devices face issues with solder protrusion and increased costs due to the use of oxide films or recessed structures to suppress solder wetting, leading to reduced bonding reliability and airtightness.
Innovation Solution
A semiconductor light-emitting device design featuring a dome-shaped transparent body with annular base and flange portions, and metal bonding patterns on both the substrate and dome-shaped body, positioned to direct solder flow away from the base edge, ensuring high airtightness and bonding reliability by minimizing void generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If oxide films or recessed structures are formed on substrates to suppress solder protrusion, then solder wettability is reduced, but manufacturing costs increase
Solution Approach 1:
The bonding patterns are designed with extended edges positioned on the outer side of the annular base portion before soldering occurs. This preliminary geometric configuration guides the solder flow during bonding, preventing protrusion without requiring additional oxide films or recessed structures, thereby avoiding increased manufacturing costs.
Solution Approach 2:
The bonding patterns have different edge positions at different locations: corner portion edges are positioned on the outer side of the annular base portion to suppress solder protrusion, while straight-line portion edges are positioned closer to the semiconductor light-emitting element. This localized variation in pattern geometry provides targeted solder control where needed without unnecessary modifications elsewhere.
2Object-generated harmful factors
If bonding patterns are extended to outer sides of annular base portion, then solder protrusion is suppressed, but void generation may increase
Solution Approach 1:
The bonding patterns have different edge positions at different locations: corner portion edges are positioned on the outer side of the annular base portion to suppress solder protrusion, while straight-line portion edges are positioned closer to the semiconductor light-emitting element. This localized variation in pattern geometry provides targeted solder control where needed without unnecessary modifications elsewhere.
Solution Approach 2:
The bonding patterns are extended beyond the annular base portion only at specific locations (corner portions) where solder protrusion is most likely to occur, rather than uniformly extending all edges. This partial extension provides sufficient solder control to prevent protrusion and void formation while maintaining bonding reliability.
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
The design suppresses solder protrusion and void formation, enhancing bonding reliability and airtightness, while allowing for efficient heat dissipation and improved light transmission.
Implementation Method 1
solder melted when an optical element and a heat dissipation substrate are bonded to each other
Implementation Method 2
The first bonding pattern and the second bonding pattern are bonded to each other via solder
Implementation Method 3
edges on inner peripheral sides of corner portions thereof are positioned on outer sides of outer peripheral edges of the annular base portion
Data Source
AI summary
A semiconductor light-emitting device includes a first bonding pattern made of metal that is formed on a substrate, and a second bonding pattern provided in a base portion and a flange portion of a dome-shaped transparent body. The first and second bonding patterns are bonded to each other via solder, to seal a space in a convex lid portion. The first and second bonding patterns have rectangular ring shapes that surround the semiconductor light-emitting element when viewed from above, at least edges on inner peripheral sides of corner portions thereof are positioned on outer sides of outer peripheral edges of an annular base portion of the convex lid portion, and edges on inner peripheral sides of straight-line portions sandwiched between the corner portions are positioned closer to the semiconductor light-emitting element than the outer peripheral edge of the annular base portion of the convex lid portion.