Flip-Chip LED Electrode Extension for Assembly Alignment
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Solution Overview
Problem
Conventional flip-chip LED package structures face issues with inaccurate alignment and poor electrode contact due to small electrode areas during assembly, leading to potential short circuits and reliability concerns.
Innovation Solution
The design includes a light emitting device with a light emitting unit, a light transmissive layer, and an encapsulant, where the first and second electrodes extend outward from the epitaxial structure layer to cover the encapsulant, increasing the electrode area and improving alignment accuracy during assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the electrode area is kept small to match the epitaxial structure layer, then the device structure remains compact, but the alignment accuracy and electrode contact during assembly deteriorate
Solution Approach 1:
The electrode structure transitions from a two-dimensional planar configuration to a three-dimensional structure by extending vertically outward from the epitaxial structure layer. The first and second electrodes extend in the vertical direction (away from the substrate) beyond the height of the epitaxial structure layer, creating an extended electrode configuration that increases surface area without expanding the horizontal footprint of the device.
2Measurement precision
If the electrode area is increased to improve alignment accuracy, then the assembly precision improves, but the device structure becomes more complex
Solution Approach 1:
The extended electrodes serve multiple functions: they provide improved alignment targets for assembly, increase bonding surface area for electrical connection, and maintain electrical continuity with the underlying epitaxial structure. The same structural extension achieves both alignment and electrical connection objectives without requiring separate components.
3Ease of manufacture
If the electrodes are aligned with the epitaxial structure layer edge, then the manufacturing process is simplified, but the electrode contact reliability during assembly deteriorates
Solution Approach 1:
The electrodes are pre-positioned to extend outward from the epitaxial structure layer during the manufacturing process, creating protruding electrode structures before assembly. This preliminary configuration ensures that when the device is assembled, the electrodes are already in optimal positions for alignment and contact, eliminating the need for post-assembly adjustment or complex alignment procedures.
Data Source
AI summary
A light emitting device includes a light emitting unit, a light transmissive layer and an encapsulant. The light emitting unit includes a substrate, an epitaxial structure layer disposed on the substrate, and a first electrode and a second electrode disposed on the same side of the epitaxial structure layer, respectively. The light emitting unit is disposed on the light transmissive layer and at least a part of the first electrode and a part of the second electrode are exposed by the light transmissive layer. The encapsulant encapsulates the light emitting unit and at least exposes a part of the first electrode and a part of the second electrode. Each of the first electrode and the second electrode extends outward from the epitaxial structure layer, and covers at least a part of an upper surface of the encapsulant, respectively.