Semiconductor Package Stepped Cavity Adhesive Design
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Solution Overview
Problem
Semiconductor device packages face challenges with heat dissipation and internal air pressure, leading to adhesion failures of light transmitting members, particularly due to increased internal air pressure causing the light transmitting member to be pushed upward and not bonded correctly, and the need for separate reflective and conductive members which increase manufacturing complexity and costs.
Innovation Solution
A semiconductor device package design featuring a body with a cavity and a stepped portion for the light transmitting member, an adhesive layer with specific edge and extending portions for improved heat dissipation, and a configuration that allows for adjustment of internal air pressure through separation sections between adhesive layers, eliminating the need for separate reflective and conductive members by using an aluminum substrate with high thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a light transmitting member is disposed on the cavity without a stepped portion, then the structure is simpler, but the adhesion fails due to increased internal air pressure pushing the light transmitting member upward
Solution Approach 1:
The cavity bottom is segmented into a stepped portion with multiple levels (first bottom surface, second bottom surface, third bottom surface) at different heights. This segmentation creates a mechanical interlock structure that prevents the light transmitting member from being pushed upward by internal air pressure, thereby improving adhesion reliability while maintaining structural clarity.
Solution Approach 2:
The stepped portion introduces a vertical dimension variation to the otherwise flat cavity bottom. By creating multiple elevation levels, the design adds dimensional complexity that effectively anchors the light transmitting member through geometric constraint, solving the adhesion problem without requiring additional materials or complex assembly procedures.
2Reliability
If separate reflective and conductive members are used, then the functional performance is improved, but the manufacturing complexity and costs increase
Solution Approach 1:
The aluminum substrate performs multiple functions simultaneously: it serves as the conductive member for electrical connections and as the reflective member for light reflection. By merging these two separate functional components into a single aluminum substrate, the design reduces manufacturing complexity and component count while maintaining the required functional performance of both conduction and reflection.
Solution Approach 2:
The aluminum substrate is designed to fulfill multiple roles within the package: structural support, electrical conduction, and optical reflection. This multi-functional design eliminates the need for separate dedicated reflective and conductive members, thereby simplifying manufacturing processes and reducing overall device complexity while preserving functional performance.
3Strength
If the adhesive layer covers the entire stepped portion, then the bonding is stronger, but the heat dissipation is reduced
Solution Approach 1:
The adhesive layer is applied selectively to specific regions of the stepped portion rather than covering the entire surface. The first adhesive layer is disposed on the first bottom surface and the second adhesive layer on the second bottom surface, leaving other areas exposed. This localized adhesive application maintains sufficient bonding strength while creating thermal pathways for effective heat dissipation from the LED chip.
Solution Approach 2:
The adhesive layer is segmented into multiple discrete portions (first adhesive layer and second adhesive layer) positioned at different locations on the stepped portion. This segmentation allows different regions to serve different functions: adhesive regions provide bonding strength while non-adhesive regions facilitate heat dissipation, resolving the contradiction between strong bonding and effective thermal management.
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 enhances heat dissipation efficiency and prevents adhesion failures by allowing heat and gas transfer through the adhesive layer, reducing manufacturing complexity and costs while maintaining internal pressure control.
Implementation Method 1
an adhesive layer which fixes the light transmitting member to the body... enhances heat dissipation efficiency
Implementation Method 2
using an aluminum substrate with high thermal conductivity
Data Source
AI summary
Disclosed herein is a semiconductor device package including: a body including a cavity; a semiconductor device disposed in the cavity; a light transmitting member disposed on the cavity; and an adhesive layer which fixes the light transmitting member to the body, wherein the cavity includes a stepped portion on which the light transmitting member is disposed, the stepped portion includes a first bottom surface and a third bottom surface spaced apart from each other in a first direction, a second bottom surface and a fourth bottom surface spaced apart from each other in a second direction perpendicular to the first direction, a first connecting portion in which the first bottom surface and the second bottom surface are connected to each other, a second connecting portion in which the second bottom surface and the third bottom surface are connected to each other, a third connecting portion in which the third bottom surface and the fourth bottom surface are connected to each other, and a fourth connecting portion in which the fourth bottom surface and the first bottom surface are connected to each other, the adhesive layer includes a first edge portion, a second edge portion, a third edge portion, and a fourth edge portion respectively—disposed on the first to fourth connecting portions and a first extending portion disposed between the first edge portion and the second edge portion, and the first extending portion has a width which is decreased in a direction toward a center between the first edge portion and the second edge portion.