LED Substrate with Reflective Metal Layer and Through-Silicon Vias
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Solution Overview
Problem
Conventional ceramic-based LED packaging substrates have limitations in light extraction efficiency, are complex and costly to manufacture, and require additional processing steps due to difficulties in metal deposition and material compatibility.
Innovation Solution
A silicon substrate with a highly reflective metal layer on one side and metal pads on the other, featuring through-silicon vias for electrical routing and thermal dissipation, eliminates the need for bonding wires on the substrate's packaging side, enhancing light extraction and simplifying fabrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If ceramic-based LED packaging substrates are used, then light absorption is reduced, but manufacturing complexity and cost increase due to extra processing steps
Solution Approach 1:
The patent changes the substrate material from ceramic to silicon, fundamentally altering the material parameter. Silicon provides inherent compatibility with standard metal deposition processes and eliminates the need for buffer layers, thereby reducing manufacturing complexity while maintaining low light absorption properties through appropriate surface treatment and metal layer design
2Ease of manufacture
If metal is deposited directly on ceramic substrates, then manufacturing steps are reduced, but deposition difficulty increases requiring buffer layers
Solution Approach 1:
The patent changes the substrate material parameter from ceramic to silicon, which has superior compatibility with direct metal deposition processes. Silicon's crystal structure and surface properties allow for straightforward metal layer formation without requiring intermediate buffer layers, thus simplifying the manufacturing process while improving ease of manufacture
3Reliability
If bonding wires are used on ceramic substrates, then electrical connections are established, but device complexity and cost increase
Solution Approach 1:
The patent merges the electrical connection function with the substrate structure itself by using through-silicon vias (TSVs) that provide direct vertical interconnects. This integration eliminates the need for separate bonding wire components, reducing structural complexity while maintaining reliable electrical connections between different layers of the LED package
4Loss of energy
If conventional ceramic substrates are used, then environmental tolerance is maintained, but light extraction efficiency decreases
Solution Approach 1:
The patent changes the substrate material from ceramic to silicon, improving light extraction efficiency through silicon's optical properties and appropriate surface structuring. Environmental tolerance is maintained through protective passivation layers and encapsulation structures that protect the silicon substrate from environmental degradation while preserving its superior optical performance
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 increases light extraction efficiency, reduces manufacturing complexity and costs, and provides improved thermal dissipation while maintaining environmental tolerance.
Implementation Method 1
a light-reflective layer disposed over the first side of the substrate... The segment of the metal layer extends through the substrate from the first side to the second side
Implementation Method 2
A segment of the metal layer extends through the substrate from the first side to the second side... providing improved thermal dissipation
Data Source
AI summary
A package structure includes: a substrate having a first side and a second side opposite to the first side; a metal layer disposed over at least a portion of the second side of the substrate; a light-reflective layer disposed over the first side of the substrate; and a photonic device bonded to the light-reflective layer from the first side. A segment of the metal layer extends through the substrate from the first side to the second side, and a portion of the substrate is completely enclosed in a cross-sectional view by the metal layer. The package structure is free of a bonding wire over the second side of the substrate.