VCSEL Package Sidewall Venting for Moisture-Resistant Sealing
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Solution Overview
Problem
Conventional VCSEL package structures with metal sidewalls face reliability issues due to the placement of air escape holes, which can lead to contamination and moisture exposure of microstructures, compromising the integrity of the package.
Innovation Solution
A package structure with a frame structure having lamination traces on its sidewall and an air hole penetrating through, where a portion of the lamination traces overlaps the edge of the air hole, allowing for the air hole to be positioned in the middle of the sidewall, reducing moisture impact and improving reliability while maintaining strength and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If air escape hole is positioned at the bottom of the package structure, then thermal expansion of gas can be accommodated, but impurities like flux can enter through the air escape hole to contaminate the microstructure during product bonding
Solution Approach 1:
The air escape hole is positioned at a specific location on the sidewall rather than at the bottom or top, creating a localized solution that prevents impurity entry while maintaining thermal expansion accommodation. This specific positioning creates a quality distinction between different regions of the package structure.
2Reliability
If air escape hole is positioned at the top of the package structure, then impurity entry is reduced, but the edge of the lens cannot be glued by adhesive so microstructures are exposed to air
Solution Approach 1:
The air escape hole is positioned at a specific location on the sidewall that allows the lens edge to be properly sealed with adhesive while still accommodating thermal expansion. This creates a localized solution that protects microstructures from moisture exposure.
3Reliability
If conventional plastic packaging with holes on sidewalls is used, then air escape hole can be positioned in the middle of sidewalls, but the manufacturing process becomes complicated
Solution Approach 1:
The package structure transitions from plastic to metal material, which fundamentally changes the manufacturing parameters and methods. Metal packaging allows for simpler processes like stamping or forming the air escape hole directly into the sidewall, reducing manufacturing complexity while maintaining the optimal positioning.
4Strength
If metal sidewalls with electroplating are used, then strength and heat dissipation are improved, but air escape holes must be disposed on the top compromising reliability
Solution Approach 1:
The air escape hole position parameter is changed from top placement (conventional metal packaging) to sidewall placement. This parameter change allows the metal packaging to maintain both its strength advantages and improved reliability by protecting microstructures from moisture exposure.
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 solution effectively reduces the impact of moisture on internal microstructures, enhances reliability, and provides better bondability and thermal performance compared to traditional plastic or metal sidewall designs.
Implementation Method 1
considering the thermal expansion of the gas, such packages are usually designed with air escape holes to avoid structural damage caused by gas expansion
Data Source
AI summary
A package structure is provided. The package structure includes a substrate, a frame structure, and a lens portion. The frame structure is disposed on the substrate. A sidewall of the frame structure has multiple lamination traces thereon. The lens portion covers the substrate. The frame structure has a through hole passing through the sidewall, and the through hole includes an edge, and a portion of the lamination traces overlaps the edge of the through hole.