LED Chip Electrode Via Structure for DBR Fracture Prevention
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Solution Overview
Problem
Conventional flip light-emitting diode chips face issues with electrode discontinuity and fractures due to the configuration of through holes in the DBR layer, affecting the reliability and efficiency of the chip.
Innovation Solution
The design includes an insulating layer with through holes and hole-defining walls that extend beyond the electrode surface, ensuring the electrodes are fully covered and avoiding fractures, while using a DBR layer for enhanced light reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the DBR layer is made thick to improve light reflection efficiency, then the light reflection performance is improved, but the electrode formation becomes difficult and fractures occur
Solution Approach 1:
The patent segments the through-hole structure into distinct sections: an upper portion with larger opening dimensions and a lower portion with smaller opening dimensions. This segmentation allows the electrode material to be deposited more effectively - the upper wider section facilitates material deposition and coverage, while the lower narrower section maintains structural integrity through the thick DBR layer, preventing fractures and ensuring continuous electrode formation.
2Manufacturing precision
If the top opening of through holes is made small to improve precision, then the electrode alignment is improved, but the electrode coverage becomes incomplete and fractures occur
Solution Approach 1:
The patent applies local quality by creating different opening dimensions at different locations of the through hole. The upper opening has larger dimensions to ensure adequate electrode material coverage and prevent fractures, while the lower opening maintains appropriate dimensions for precise electrode alignment. This spatial variation in opening quality allows both precision and continuity requirements to be satisfied simultaneously.
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 design improves the reliability and efficiency of the light-emitting diode chip by ensuring continuous electrode layers and effective light reflection, enhancing the chip's performance and longevity.
Implementation Method 1
The DBR is formed as a multilayered structure and includes different dielectric layers that are alternately stacked on one another. Light transmitted into the DBR may undergo a near total reflection in a certain frequency range.
Implementation Method 2
The insulating layer has a through hole and a hole-defining wall that defines the through hole. The top peripheral edge has two opposite end points. A projection of at least one of the end points of the top peripheral edge of the hole-defining wall on the first conductivity type semiconductor layer falls outside a projection of the top surface of the first electrode on the first conductivity type semiconductor layer.
Data Source
AI summary
A light-emitting diode chip includes a light-emitting unit, a first electrode, an insulating layer, and a second electrode. The first electrode is disposed on the light-emitting unit. The insulating layer is disposed on the first electrode and the light-emitting unit, and has a through hole and a hole-defining wall. The hole-defining wall has a top peripheral edge that has two opposite end points. A projection of at least one of the end points of the top peripheral edge on the light-emitting unit falls outside a projection of a top surface of the first electrode on the light-emitting unit. The second electrode is disposed on the insulating layer and fills the through hole to electrically connect to the first electrode.