LED Reflective Layer and Bonding Pad Layout for Stable Miniaturization
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Solution Overview
Problem
Current semiconductor light emitting devices face challenges in improving optical characteristics and reliability, particularly in reducing size and increasing productivity for diverse applications.
Innovation Solution
A semiconductor light emitting device structure is developed, featuring a first and second conductivity type semiconductor layer, an active layer, a reflective layer resistant to aqueous solutions like TMAH, KOH, and NH4OH, and an insulating spacer conformally formed along the substrate, with a bonding pad design that includes a shell shape with decreasing width, enhancing structural stability and optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the device size is reduced to improve integration and productivity, then the margin area is minimized, but manufacturing precision and structural stability become more difficult to maintain
Solution Approach 1:
The device is segmented into distinct functional layers including semiconductor layers, reflective layer, insulating layer, and bonding pad structure. This segmentation allows each component to be optimized independently while maintaining overall structural integrity in the miniaturized device
Solution Approach 2:
The bonding pad is designed with a nested structure where the shell shape encompasses the reflective layer, and the insulating spacer is conformally formed within the margins. This nesting approach maximizes space utilization while maintaining structural stability in the reduced-size device
2Productivity
If the bonding pad margin area is minimized to reduce device size, then productivity is improved, but the reliability of electrical connections may be compromised
Solution Approach 1:
The bonding pad is designed with a shell shape that features curved boundaries instead of sharp corners. This curvature distributes mechanical stress more evenly across the connection interface, maintaining connection reliability while minimizing the overall margin area for improved productivity
3Manufacturing precision
If a reflective layer material resistant to aqueous solutions (TMAH, KOH, NaOH, NH4OH) is used to improve etching stability, then manufacturing precision is improved, but the material selection becomes more limited
Solution Approach 1:
The reflective layer uses materials with specific chemical resistance properties to TMAH, KOH, NaOH, and NH4OH aqueous solutions. This parameter-based material selection ensures etching stability during manufacturing while the design accommodates various material options including metals and metal alloys that exhibit this resistance
4Illumination intensity
If the insulating spacer is conformally formed to improve optical characteristics, then light emission efficiency is enhanced, but the device complexity increases
Solution Approach 1:
The insulating spacer serves multiple functions: it provides electrical insulation, maintains structural spacing for optimal optical characteristics, and contributes to mechanical stability. This multi-functionality enhances light emission efficiency while avoiding additional complex components
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 improves optical characteristics, reduces device size, and increases productivity by minimizing the margin area and allowing for more efficient manufacturing processes, resulting in enhanced structural stability and improved light emission efficiency.
Implementation Method 1
a reflective layer formed on a part of a top surface of the electrode layer
Data Source
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AI summary
A semiconductor light emitting device includes a first conductivity type semiconductor layer, a second conductivity type semiconductor layer arranged on the first conductivity type semiconductor layer, an active layer between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer, an electrode layer formed on a top surface of the second conductivity type semiconductor layer, a reflective layer formed on a part of a top surface of the electrode layer, a bonding pad formed on a top surface of the reflective layer, an insulating layer formed on another part of the top surface of the electrode layer, and an insulating spacer conformally formed along side walls of the first conductivity type semiconductor layer, the second conductivity type semiconductor layer, and the active layer, and covering a part of the side wall of the insulating layer . The reflective layer includes a material that is not etched by an aqueous solution including one of tetramethyl ammonium hydroxide (TMAH), KOH, NaOH, and NH4OH and the bonding pad has a shell shape including a part of which the width gradually decreases as the part distances from the reflective layer.