Flip-Chip LED Mesa Structure Eliminates Protective Layer
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Solution Overview
Problem
The existing flip-chip structure of III group semiconductor light emitting devices requires complex and costly processes due to the need for high accuracy etching of holes (vias) and the use of multiple layers for reflectivity and protection, which increases production costs and alignment defects.
Innovation Solution
A flip-chip structure with a linear convex mesa replaces the plurality of holes (vias) and uses a Bragg's reflective layer and oxide insulation layers as both a reflector and insulation, eliminating the need for a metal protective layer and simplifying the process by integrating the transparent conductive layer and mesa pattern simultaneously.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high accuracy etching of holes (vias) is used to create metal protective layer, then reliability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The invention extracts and eliminates the metal protective layer (guard metal) and its associated complex etching holes/vias from the flip-chip LED structure. By removing this redundant protective component, the patent simplifies the device structure and manufacturing process while maintaining electrode stability through alternative design approaches.
Solution Approach 2:
The patent integrates multiple functions into the electrode structure itself. The electrode serves both as electrical contact and as its own protective element, eliminating the need for separate metal protective layers. This multi-functional design reduces structural complexity while maintaining reliability.
2Reliability
If multiple layers (metal protective layer, insulation layers, reflector) are used in flip-chip structure, then reliability is improved, but manufacturing cost and process complexity increase
Solution Approach 1:
The invention merges the electrode structure with its protective function, combining what were previously separate components (electrode and metal protective layer) into a unified structure. This consolidation reduces the number of manufacturing steps and material layers required, lowering production costs while maintaining electrode stability.
Solution Approach 2:
The electrode is designed to perform multiple functions simultaneously: electrical conduction, mechanical support, and self-protection. This multi-functionality eliminates the need for separate protective layers and insulation structures, simplifying manufacturing and reducing costs.
3Manufacturing precision
If transparent conductive layer and mesa pattern are made separately, then manufacturing precision is improved, but production time and cost increase
Solution Approach 1:
The patent merges the formation of the transparent conductive layer and the mesa pattern into a single simultaneous manufacturing step. This integrated approach maintains alignment precision because both features are created in the same process window, while dramatically improving production efficiency by eliminating sequential processing steps.
Solution Approach 2:
The manufacturing process is designed to prepare and create both the transparent conductive layer and mesa pattern in advance during the same processing stage, ensuring their mutual alignment is established beforehand. This preliminary simultaneous action prevents subsequent alignment issues while accelerating production.
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 production costs, simplifies the process, and improves alignment by eliminating the need for a metal protective layer, while maintaining or enhancing photoelectric properties compared to traditional structures.
Implementation Method 1
uses a Bragg's reflective layer and oxide insulation layers as both a reflector
Data Source
AI summary
This application refers to a flip-chip structure of Group III semiconductor light emitting device. The flip-chip structure includes: a substrate, a buffer layer, nitride semiconductor layer, an active layer, a P type nitride semiconductor layer, a transparent conductive layer, a first insulation layer, a P type contact metal, a N type contact metal, a second insulation layer, a flip-chip P type electrode and a flip-chip N type electrode. The substrate, the buffer layer, the N type nitride semiconductor layer, the active layer, the P type nitride semiconductor layer which grow sequentially from bottom to top form a linear convex mesa. In this application, structure of the first insulation layer which is formed by aBraggs reflective layer, a metal layer and the multilayer oxide insulation layer, acts as a reflector structure and an insulation layer to replace the flip-chip reflector structure design and the first insulation layer, so that a metal protective layer can be omitted.