LED Conductive Via Structure for Fine-Pitch Encapsulated Interconnects
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Solution Overview
Problem
The semiconductor industry faces challenges in integrating high-density optical features into semiconductor devices, particularly in forming conductive vias for light emitting diodes (LEDs) with fine pitches and high aspect ratios, which are prone to collapse during the manufacturing process.
Innovation Solution
The process involves forming conductive vias after attaching the light emitting diodes to a substrate, using a photosensitive encapsulant like low-temperature polyimide, and creating openings through etching instead of development, allowing for finer pitches and higher aspect ratios, and connecting these vias to underlying connecting pads with conductive lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conductive vias are formed with fine pitches and high aspect ratios, then integration density is improved, but the via structure becomes unstable and prone to collapse
Solution Approach 1:
The LED is attached to the substrate before forming the conductive vias. This preliminary attachment provides structural support during via formation, preventing collapse of high aspect ratio vias with fine pitches while maintaining integration density
Solution Approach 2:
The conductive via formation process is segmented into multiple stages: first forming openings through the encapsulant, then depositing conductive material in layers, and finally completing the via structure. This segmentation allows each stage to be optimized independently, ensuring stability during the delicate via formation process
2Ease of manufacture
If conductive vias are formed before attaching the light emitting diode, then the manufacturing process is simplified, but the conductive vias are prone to collapse due to lack of structural support
Solution Approach 1:
The LED attachment is performed as a preliminary action before conductive via formation. The LED structure serves as a mechanical support framework that stabilizes the substrate and prevents via collapse during subsequent processing steps
Solution Approach 2:
The LED structure acts as a cushioning support element placed beforehand to protect against potential via collapse. This structural reinforcement is positioned in advance to prevent damage during the via formation process
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 approach reduces the chances of conductive via collapse and enables the formation of finer pitch conductive vias with higher aspect ratios, enhancing the integration density and reliability of LED-based semiconductor devices.
Implementation Method 1
creating openings through etching instead of development
Data Source
AI summary
In an embodiment, a device includes: an interconnect structure including a first contact pad, a second contact pad, and an alignment mark; a light emitting diode including a cathode and an anode, the cathode connected to the first contact pad; an encapsulant encapsulating the light emitting diode; a first conductive via extending through the encapsulant, the first conductive via including a first seed layer, the first seed layer contacting the second contact pad; a second conductive via extending through the encapsulant, the second conductive via including a second seed layer, the first seed layer and the second seed layer including a first metal; and a hardmask layer between the second seed layer and the alignment mark, the hardmask layer including a second metal, the second metal different from the first metal.