Optoelectronic Semiconductor Chip Mirror Layer Encapsulation
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Solution Overview
Problem
Thin-film light emitting diode chips face corrosion issues due to exposed silver mirror layers during the singulation process, as dielectric encapsulation layers can be damaged, compromising protection against moisture and oxidation.
Innovation Solution
A combination of metallic and dielectric encapsulation layers is used for the mirror layer, where metallic layers protect the side surfaces facing the outer chip and dielectric layers are used for surfaces facing trenches, enhancing mechanical durability and radiation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dielectric encapsulation layer is used to protect the mirror layer, then corrosion protection is provided, but the encapsulation layer can be damaged during the singulation process
Solution Approach 1:
The patent applies a composite encapsulation structure combining a metallic encapsulation layer (first encapsulation layer) and a dielectric encapsulation layer (second encapsulation layer). The metallic layer provides mechanical durability and protection during singulation, while the dielectric layer provides corrosion protection. This composite approach resolves the contradiction by combining materials with complementary properties.
Solution Approach 2:
The patent applies different encapsulation materials to different locations of the mirror layer. The metallic encapsulation layer is applied to side surfaces of the mirror layer that are exposed or will be exposed after singulation, while the dielectric encapsulation layer is applied to other surfaces. This local differentiation optimizes both mechanical protection where needed and corrosion protection where appropriate.
2Strength
If a metallic encapsulation layer is used for the mirror layer, then mechanical durability is improved, but radiation efficiency may be impaired
Solution Approach 1:
The patent applies the metallic encapsulation layer only to specific side surfaces of the mirror layer where mechanical protection is needed, rather than covering the entire mirror layer. This localized application provides mechanical durability where required while minimizing the impact on radiation efficiency by leaving other surfaces uncovered or covered with transparent dielectric material.
Solution Approach 2:
The composite encapsulation structure allows the metallic layer to provide mechanical protection while the dielectric layer maintains optical transparency. The combination enables both mechanical durability and radiation efficiency to be achieved simultaneously through the synergistic properties of the two materials.
3Ease of operation
If the mirror layer is exposed in trenches between active regions, then series connection of active regions is enabled, but the exposed mirror layer is susceptible to corrosion
Solution Approach 1:
The patent uses a composite encapsulation system where the metallic encapsulation layer provides a protective barrier against corrosion for the exposed mirror layer in trenches, while the dielectric encapsulation layer provides additional environmental protection. This allows the mirror layer to remain exposed for electrical connection purposes without being susceptible to corrosion.
Solution Approach 2:
The patent applies encapsulation layers specifically to the exposed side surfaces of the mirror layer in the trenches between active regions. This localized encapsulation provides corrosion protection exactly where the mirror layer is vulnerable while maintaining the electrical connectivity function of the exposed mirror layer.
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 effectively protects the mirror layer from corrosion and mechanical damage while maintaining high radiation efficiency by using metallic encapsulation for outer surfaces and transparent dielectric encapsulation for inner surfaces.
Implementation Method 1
it is advantageous if that side of the semiconductor layer sequence which faces the carrier substrate is provided with a mirror layer, in order that radiation emitted in the direction of the carrier substrate is deflected in the direction of the radiation exit surface and the radiation efficiency is thereby increased
Data Source
AI summary
An optoelectronic semiconductor chip is disclosed. The optoelectronic semiconductor chip includes a semiconductor layer sequence having an active zone suitable for emitting radiation, a carrier substrate, and a mirror layer, the mirror layer being arranged between the semiconductor layer sequence and the carrier substrate, wherein the semiconductor layer sequence is subdivided into a plurality of active regions arranged alongside one another, wherein the plurality of active regions are separated from one another in each case by a trench in the semiconductor layer sequence, wherein the trench in each case severs the semiconductor layer sequence and the mirror layer, wherein the mirror layer has side surfaces facing a trench and side surfaces facing an outer side of the semiconductor chip, wherein the side surfaces of the mirror layer that face an outer side of the semiconductor chip have a metallic encapsulation layer.