Semiconductor Package Substrate Flow-Suppressing Portion
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Solution Overview
Problem
In semiconductor light-emitting devices, the AuSn eutectic solder used as a joining member can flow into the cavity, leading to uneven thickness and stress that may cause the lid member to crack or come off.
Innovation Solution
A semiconductor package substrate with a flow-suppressing portion that spatially separates the mounting region and the reflective wall, preventing the joining member from flowing into the cavity, and featuring a step-shaped first flow-suppressing portion to prevent AuSn eutectic solder from trickling down and a second flow-suppressing portion between the mounting surface and the reflective wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If AuSn eutectic solder is used as the joining member, then the lid member can be securely joined to the rim portion, but the solder may trickle down the wall portion and flow into the cavity, causing uneven thickness and stress that may cause the lid member to crack or come off
Solution Approach 1:
The cavity wall is segmented into multiple portions: the mounting surface, the first wall portion (reflective wall), the second wall portion (flow suppressor), and the third wall portion. This segmentation prevents the solder from flowing directly into the cavity by creating a stepped structure that blocks the flow path.
Solution Approach 2:
The flow suppressor portion is prepared in advance on the cavity wall before soldering. This preliminary structural preparation ensures that when the AuSn eutectic solder is applied, it cannot trickle down into the cavity, thus preventing future cracking or detachment issues.
2Quantity of substance
If the AuSn eutectic solder flows into the cavity, then the amount of solder remaining in the mounting region is reduced, but this causes different thickness between portions and generates stress
Solution Approach 1:
The cavity wall is divided into distinct segments including the flow suppressor portion that creates a physical barrier. This segmentation ensures solder remains confined to the mounting region, maintaining uniform thickness and preventing composition instability.
Solution Approach 2:
The flow suppressor portion acts as an intermediary structure between the mounting region and the cavity. It mediates the solder flow by blocking it, ensuring the solder stays in the mounting region with uniform distribution rather than flowing into the cavity and creating thickness variations.
3Reliability
If a flow-suppressing portion is added to prevent solder from flowing into the cavity, then the lid member integrity is improved, but the device structure becomes more complex
Solution Approach 1:
The cavity wall is segmented into functional portions (mounting surface, reflective wall, flow suppressor). While this adds structural elements, each segment serves a specific function that can be integrated into the manufacturing process, balancing reliability improvement with manageable complexity.
Solution Approach 2:
The flow suppressor portion is designed to serve multiple purposes: it prevents solder flow into the cavity, maintains solder thickness uniformity, and provides a structural foundation for the reflective wall. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.
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
Prevents AuSn eutectic solder from flowing into the cavity, thereby reducing the likelihood of lid member cracking or detachment, ensuring a stable and secure assembly.
Implementation Method 1
a reflective wall being provided around the mounting surface and configured to reflect light emitted from the semiconductor light-emitting element to be mounted on the mounting surface
Data Source
AI summary
A semiconductor package substrate includes a semiconductor housing space including a mounting surface being provided on a bottom side and configured to mount a semiconductor light-emitting element, and a reflective wall being provided around the mounting surface and configured to reflect light emitted from the semiconductor light-emitting element to be mounted on the mounting surface; a mounting region being provided at a rim portion and configured to mount a lid member for covering the semiconductor light-emitting element; and a flow-suppressing portion separating the mounting region and the reflective wall spatially in such a manner that a joining member joining the lid member to the rim portion is suppressed from flowing from the mounting region into the semiconductor housing space.