LED Package Pad Recess Structure for Uniform Solder Thickness
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Solution Overview
Problem
Existing electronic package devices experience internal stress due to variations in the vertical thickness of solder paste, which affects the reliability and stability of the connection between the package substrate and the light-emitting device.
Innovation Solution
The electronic package device incorporates a package substrate with a pad design that includes a first portion and a second portion, where the second portion is positioned at the edge of the first portion, forming a recess that is filled by the solder paste, thereby maintaining consistent vertical thickness and reducing stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional pad design is used without a recess structure, then the manufacturing process is simpler, but the vertical thickness of solder paste varies significantly causing internal stress
Solution Approach 1:
The pad structure is segmented into a first pad and a second pad positioned at the edge, creating a recess structure between them. This segmentation allows the solder paste to be contained within the recess, ensuring uniform vertical thickness and reducing internal stress in the electronic package device.
Solution Approach 2:
The pad structure transitions from a conventional flat two-dimensional design to a three-dimensional structure with a recess. This dimensional change creates a depth component that confines the solder paste, maintaining consistent vertical thickness and eliminating the internal stress problems associated with conventional flat pad designs.
2Manufacturing precision
If the width of the light-emitting device is made equal to the width of the pad, then the alignment and mounting precision is improved, but the pad structure becomes more complex requiring a recess design
Solution Approach 1:
The pad is divided into a first pad and a second pad at the edge, forming a recess structure. This segmentation enables the pad width to match the light-emitting device width for precise alignment, while the recess structure manages the solder paste thickness without adding excessive complexity.
Solution Approach 2:
The recess structure is implemented locally at specific regions of the pad where solder paste containment is needed, rather than redesigning the entire pad structure. This localized approach maintains alignment precision while minimizing overall structural complexity.
Data Source
AI summary
Provided is an electronic package device including a package substrate including a flat plate and a pad on the flat plate, wherein a width of the flat plate in a first horizontal direction is greater than a width of the pad in the first horizontal direction, and a light-emitting device on the package substrate, wherein the pad includes a first portion, and a second portion positioned on a top surface of the first portion and positioned at an edge of the top surface of the first portion, and a width of the light-emitting device in the first horizontal direction is substantially equal to a width of the pad in the first horizontal direction.