Optical Semiconductor Package Venting Layout Against Flux Ingress
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Solution Overview
Problem
Existing optical semiconductor devices face reliability issues due to the risk of flux entering ventilation holes, which can lead to foreign matter contamination and reduced air permeability, especially during mounting and thermal expansion/contraction.
Innovation Solution
The optical semiconductor device features a wiring board with a ventilation hole that penetrates both surfaces, where the second surface includes a disposition region with a resist layer and a non-disposition region. The non-disposition region has a first region for the ventilation hole and a second region extending to the edge, preventing flux entry and ensuring air flow, thus enhancing reliability against flux ingress and thermal expansion/contraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ventilation hole is formed in the insulating substrate, then the air permeability is improved, but the flux may enter the ventilation hole when the semiconductor device is mounted on a printed circuit board with solder
Solution Approach 1:
The patent applies local quality by creating a resist layer that is selectively disposed in specific regions (disposition regions) between electrodes, while leaving other regions (non-disposition regions) without resist layer. This localized application of resist material allows the ventilation hole to remain open for air permeability while preventing flux from entering through the resist layer in critical areas.
Solution Approach 2:
The resist layer serves as an intermediary barrier between the ventilation hole and the flux. By placing the resist layer in disposition regions between electrodes, it acts as a protective mediator that blocks flux from reaching the ventilation hole while allowing air to flow through the non-disposition regions where no resist layer is present.
2Reliability
If the ventilation hole is formed in the side surface of the semiconductor device, then the air permeability is improved, but foreign matter may enter through the ventilation hole
Solution Approach 1:
The patent applies local quality by creating a resist layer that is selectively disposed in specific regions (disposition regions) between electrodes, while leaving other regions (non-disposition regions) without resist layer. This localized application of resist material allows the ventilation hole to remain open for air permeability while preventing flux from entering through the resist layer in critical areas.
Solution Approach 2:
The resist layer serves as an intermediary barrier between the ventilation hole and the flux. By placing the resist layer in disposition regions between electrodes, it acts as a protective mediator that blocks flux from reaching the ventilation hole while allowing air to flow through the non-disposition regions where no resist layer is present.
3Reliability
If the resist layer is disposed between all electrodes, then the electrical insulation is improved, but the air flow through the ventilation hole is restricted
Solution Approach 1:
The patent applies local quality by creating a resist layer that is selectively disposed in specific regions (disposition regions) between electrodes, while leaving other regions (non-disposition regions) without resist layer. This localized application of resist material allows the ventilation hole to remain open for air permeability while preventing flux from entering through the resist layer in critical areas.
Solution Approach 2:
The patent applies segmentation by dividing the second surface into disposition regions and non-disposition regions. The resist layer is segmented to be present only in disposition regions between electrodes, while non-disposition regions remain clear to allow air flow. This spatial segmentation resolves the contradiction between electrical insulation and air flow efficiency.
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 effectively prevents flux from entering the ventilation hole, ensuring reliability and improving resistance to thermal expansion and dew condensation, while allowing for efficient air flow and secure electrical connections.
Implementation Method 1
Since the flux is less likely to flow into the non-disposition region, by disposing the ventilation hole in the first region, it is possible to prevent the flux from entering the ventilation hole
Implementation Method 2
air easily flows into the second region from the outside, and as a result, the flowing air can prevent the flux from entering the ventilation hole
Implementation Method 3
the formation of the ventilation hole suppresses an increase in pressure inside the semiconductor device
Data Source
AI summary
An optical semiconductor device includes a wiring board including a first surface and a second surface, a cover disposed to face the first surface, an optical semiconductor element disposed on the first surface, a plurality of electrodes disposed on the second surface, and a resist layer disposed on the second surface and located at least between the plurality of electrodes. A ventilation hole that penetrates the first surface and the second surface is formed in the wiring board. The second surface includes a disposition region in which the resist layer is disposed and a non-disposition region in which the resist layer is not disposed. The non-disposition region includes a first region in which the ventilation hole is disposed and a second region that reaches an edge of the second surface from the first region.