Beveled Trench Light-Emitting Device Void Reduction
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Solution Overview
Problem
Conventional light-emitting devices face connection failure issues due to voids formed during the bonding process, leading to increased resistance and reduced connection area between the metal layer and the carrier substrate, affecting electrical characteristics and light emission efficiency.
Innovation Solution
The implementation of a beveled trench with an inclined inner sidewall and a dielectric layer, along with a metal layer and conductive protruding structures within the trench, enhances the connection area and reduces resistance by allowing for better filling and electro-plating processes, thereby increasing the contact area between the metal layer and the connection layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a deep trench is formed in the semiconductor layer sequence, then the electrical insulation between the second semiconductor layer and the active layer is improved, but the filling of electrically conductive material becomes difficult and voids are formed
Solution Approach 1:
The patent applies asymmetry by changing the trench shape from a conventional vertical profile to a beveled profile with specific angle ranges (30-60 degrees). This asymmetric geometry allows the trench to maintain sufficient depth for electrical insulation while providing a wider opening that facilitates complete filling with electrically conductive material, preventing void formation.
Solution Approach 2:
The patent changes the geometric parameters of the trench by specifying the beveled angle (30-60 degrees) and the depth-to-width ratio. These parameter modifications optimize the balance between maintaining electrical insulation (requiring sufficient depth) and enabling complete filling (requiring accessible geometry), thereby resolving the contradiction between reliability and manufacturing precision.
2Reliability
If the trench is deep to ensure electrical insulation, then the insulation performance is improved, but the connection area between the metal layer and the connection layer is reduced
Solution Approach 1:
The beveled trench geometry creates an asymmetric structure where the opening area is larger than the bottom area. This allows the trench to extend deeply enough for electrical insulation while maintaining a larger opening that accommodates a greater connection area between the metal layer and the connection layer, resolving the contradiction between insulation performance and connection area.
3Ease of manufacture
If the trench profile is concave after filling, then voids are formed between the metal layer and the connection layer, but the filling process is simplified
Solution Approach 1:
The beveled trench profile with a wider opening and narrower bottom prevents the formation of concave profiles during filling. The asymmetric geometry ensures that filling material flows smoothly from the opening to the bottom without trapping air or creating voids, thereby maintaining both ease of manufacture (simplified filling) and connection quality (void-free interface).
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 reduces the size of voids and enhances the connection area between the metal and connection layers, lowering the resistance and improving light emission efficiency.
Implementation Method 1
a dielectric layer formed on the inner sidewall of the beveled trench and the second main side
Implementation Method 2
a metal layer formed on the dielectric layer... a first connection layer connecting the carrier substrate and the semiconductor layer sequence
Data Source
AI summary
A light-emitting device comprises a semiconductor layer sequence comprising a first semiconductor layer having a first electrical conductivity, a second semiconductor layer having a second electrical conductivity, and an active layer interposed between the first semiconductor layer and the second semiconductor layer; a plurality of beveled trenches formed in the semiconductor layer sequence; a plurality of protruding structures respectively formed in the plurality of beveled trenches; a dielectric layer formed on the second semiconductor layer and an inner sidewall of the plurality of beveled trenches; a reflecting layer interposed between the semiconductor layer sequence and the dielectric layer; and a metal layer formed along the inner sidewall of the plurality of beveled trenches, wherein the dielectric layer, the reflecting layer and the metal layer are overlapping, the plurality of protruding structures and the reflecting layer are not overlapping.