Flip-Chip LED Chip Curved Pattern Regions Current Crowding
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Solution Overview
Problem
Flip-chip LED package devices face issues with current crowding due to low electrical conductivity in nitride-based layers, leading to reduced light emission efficiency and reliability, especially in high-temperature and high-humidity environments, and the underfill technique has limitations in preventing moisture absorption and photon absorption.
Innovation Solution
The LED chip design includes a first pattern region with curved parts and protrusion patterns, and a second pattern region surrounding it, with strategically arranged nitride-based semiconductor layers and electrode layers to reduce electrical resistance and improve current spreading, along with a submount substrate for flip-chip bonding that seals the LED chip to prevent moisture exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional LED chip structure is used, then manufacturing is simple, but current crowding occurs due to low electrical conductivity in nitride-based layers
Solution Approach 1:
The LED chip structure is divided into multiple pattern regions (first pattern region with curved parts and protrusion patterns, second pattern region surrounding it) with different layer configurations. This segmentation allows optimization of current spreading in different areas, reducing current crowding while maintaining manufacturing feasibility through systematic layer stacking.
Solution Approach 2:
Different regions of the LED chip are given different structural qualities - the first pattern region has curved parts and protrusion patterns with specific layer stacks, while the second pattern region has a surrounding structure. This local differentiation optimizes electrical conductivity and current spreading in areas where it is most needed, improving light emission efficiency without uniformly increasing complexity.
2Reliability
If conventional packaging is used, then moisture protection is insufficient, but sealing structure increases device complexity
Solution Approach 1:
The LED chip pattern regions are designed to work together with the submount substrate to form an integrated sealing structure. The first and second pattern regions, when combined with the submount substrate, create a unified structure that provides both electrical functionality and moisture protection, reducing the need for separate protective components.
3Reliability
If underfill technique is used, then some moisture protection is provided, but photons are absorbed reducing optical output
Solution Approach 1:
The design extracts and eliminates the need for underfill material by implementing a sealing structure formed by the pattern regions and submount substrate combination. This removes the harmful underfill layer that would otherwise absorb photons, while still providing the necessary moisture protection function through the alternative sealing approach.
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 enhances light emission efficiency by reducing electrical resistance and preventing moisture absorption, thereby improving the reliability and optical output of the LED package device.
Implementation Method 1
a first pattern region having one or more curved parts; and a second pattern region at least partially surrounding the first pattern region. The first pattern region can include a first conductive type nitride-based semiconductor layer, an active layer, a second conductive type nitride-based semiconductor layer, a top electrode layer, and a top bump layer
Implementation Method 2
The submunt substrate can be structured to form a flip-chip bond with the LED chip
Implementation Method 3
An LED is a photoelectric conversion element which applies a forward current to both ends of a P-N junction and emits light
Implementation Method 4
an active layer disposed over the first semiconductor layer structured to emit light at a predetermined level of energy
Data Source
AI summary
A light emitting diode (LED) chip can include: a first pattern region having one or more curved parts; and a second pattern region at least partially surrounding the first pattern region. The first pattern region can include a first conductive type nitride-based semiconductor layer, an active layer, a second conductive type nitride-based semiconductor layer, a top electrode layer, and a top bump layer stacked over a substrate, the second pattern region can include a first conductive type nitride-based semiconductor layer, a bottom electrode layer, and a bottom bump layer stacked over the substrate, and the first pattern region can include one or more protrusion patterns formed in the one or more curved part.