Micro-LED Electrode Structure for Ultra-Small Bonding Pads
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Solution Overview
Problem
Existing bonding methods for semiconductor light emitting devices with diameters of several tens of μm are limited in applying to devices with diameters of several μm, hindering their integration with substrates having disposed wiring.
Innovation Solution
A semiconductor light emitting device structure featuring a first conductivity type electrode and a second conductivity type electrode with a protruding portion covering the insulating part, allowing simultaneous connection to a substrate's wiring during transfer, and a display device design with wiring electrodes spaced apart to accommodate these devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional bonding methods are used for semiconductor light emitting devices with diameters of several tens of μm, then bonding is achievable, but the method cannot be applied to devices with diameters of several μm
Solution Approach 1:
The electrode structure is segmented into multiple functional portions: a first electrode portion for electrical contact, a second electrode portion extending laterally to provide mechanical anchoring, and a third electrode portion forming a bonding pad. This segmentation allows the electrode to fulfill multiple functions simultaneously, enabling reliable bonding of ultra-small devices
Solution Approach 2:
The electrode structure transitions from a conventional planar configuration to a three-dimensional structure with lateral extension. The second electrode portion extends in a direction substantially perpendicular to the light emission direction, adding a spatial dimension that provides mechanical stability and bonding surface for ultra-small devices
2Productivity
If the device size is reduced to several μm, then high efficiency and compact display are achieved, but conventional bonding methods become inapplicable
Solution Approach 1:
The electrode structure is pre-configured with extended portions and bonding pads before device assembly. The second electrode portion laterally extends and the third electrode portion forms a bonding pad on the same surface as the light emitting element, preparing the device in advance for reliable bonding operations
Solution Approach 2:
The extended second electrode portion and bonding pad structure act as an intermediary between the ultra-small light emitting element and the bonding process. This intermediate structure provides a sufficient bonding surface area that bridges the gap between the tiny device size and the requirements of conventional bonding methods
3Area of stationary object
If the electrode structure is extended laterally to provide bonding surface, then bonding area increases, but device complexity increases
Solution Approach 1:
The multi-portion electrode structure performs multiple functions: the first electrode portion provides electrical contact, the second electrode portion provides lateral extension for mechanical stability and additional bonding surface, and the third electrode portion provides a dedicated bonding pad. This multi-functionality increases bonding area without requiring separate components for each function
Data Source
AI summary
Discussed is a semiconductor light-emitting element that can include a body part including a first conductivity type semiconductor layer, an active layer on the first conductivity type semiconductor layer, and a second conductivity type semiconductor layer on the active layer, an insulating part covering at least a side surface of the body part, and an electrode part including a first conductivity type electrode in contact with the first conductivity type semiconductor layer, and a second conductivity type electrode in contact with the second conductivity type semiconductor layer, wherein the second conductivity type electrode includes a first portion on the second conductivity type semiconductor layer, and a second portion extending from the first portion and covering at least a portion of the insulating part, and the second portion protrudes further, with respect to the side surface of the body part, than the first conductivity type electrode.