LED Insulating Film Segmentation for Thermal Stress Relief
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Solution Overview
Problem
High current injection in semiconductor light emitting devices leads to temperature increases, reducing light emission efficiency due to heat generation and potential thermal stress causing cracks in the inorganic insulating film, resulting in decreased reliability and unintended short circuits.
Innovation Solution
The use of an inorganic insulating film with a thin, high thermal conductivity layer between electrodes and organic insulating film to enhance heat dissipation and distribute current effectively, while the organic insulating film relaxes thermal stress concentrations by covering end portions of interconnection layers, preventing cracks and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high current is injected to increase brightness, then illumination intensity is improved, but temperature increases causing decrease in light emission efficiency
Solution Approach 1:
The patent segments the insulating film structure into multiple functional layers: a lower inorganic insulating film for heat dissipation and upper organic insulating films for stress relief and protection. This segmentation allows each layer to specialize in specific functions, enabling high current injection while maintaining efficiency through improved thermal management.
Solution Approach 2:
The patent employs a composite insulating film structure combining inorganic materials (such as silicon oxide or silicon nitride) with organic materials (such as resin or polymer). This composite structure leverages the high thermal conductivity of inorganic materials for heat dissipation while utilizing the stress-absorbing properties of organic materials, thereby resolving the contradiction between high current injection and maintaining light emission efficiency.
2Illumination intensity
If high current is injected to increase brightness, then illumination intensity is improved, but thermal stress causes cracks in inorganic insulating film reducing reliability
Solution Approach 1:
The patent applies beforehand cushioning by placing stress-absorbing organic insulating films above the rigid inorganic insulating film. These organic layers act as cushioning elements that absorb thermal stress before it can propagate to the inorganic film, preventing cracks and maintaining reliability under high current injection conditions.
Solution Approach 2:
The composite insulating film structure combines rigid inorganic materials for heat dissipation with flexible organic materials for stress absorption. This material combination allows the structure to withstand thermal expansion and contraction forces without developing cracks, thereby maintaining film integrity during high current operation.
3Temperature
If inorganic insulating film is used for heat dissipation, then temperature is reduced, but thermal stress concentrates at interconnection layer ends causing cracks
Solution Approach 1:
The patent applies local quality by providing different insulating film properties at different locations: the inorganic insulating film near the heat source provides high thermal conductivity for heat dissipation, while the organic insulating films at the interconnection layer ends provide stress absorption and flexibility. This spatial variation in material properties resolves the contradiction between heat dissipation and stress distribution.
Solution Approach 2:
The multi-layer composite insulating film structure assigns different functional roles to each layer based on its material properties. The inorganic layer handles thermal management while the organic layers handle mechanical stress management, creating a synergistic system that achieves both effective heat dissipation and uniform stress distribution.
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 configuration allows for high current injection with improved heat dissipation and reduced thermal stress, maintaining high brightness and reliability by preventing cracks and unintended short circuits, thus enhancing the semiconductor light emitting device's performance.
Implementation Method 1
an inorganic insulating film with a thin, high thermal conductivity layer between electrodes and organic insulating film to enhance heat dissipation
Implementation Method 2
the organic insulating film relaxes thermal stress concentrations by covering end portions of interconnection layers, preventing cracks
Data Source
Figure 1A~1B
Figure 2
Figure 3~3C
AI summary
According to one embodiment, a semiconductor light emitting device includes a semiconductor layer (15), a p-side electrode (16), an n-side electrode (17), an inorganic insulating film (14), a p-side interconnection portion (21), an n-side interconnection portion (22), and an organic insulating film (20). The organic insulating film is provided on the inorganic insulating film, at least on a portion between the p-side interconnection portion and the n-side interconnection portion. An end portion (216) of the p-side interconnection portion on the n-side interconnection portion side and an end portion (226) of the n-side interconnection portion on the p-side interconnection portion side override the organic insulating film.