Light-Emitting Device Electrode Segmentation for Insulating Layer Formation
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Solution Overview
Problem
Existing light-emitting device packages with a flip-chip-bonding structure face issues with the correct formation of insulating layers due to thick n-type electrodes, leading to deteriorated electrical characteristics.
Innovation Solution
A light-emitting device with a substrate, conductive semiconductor layers, electrodes, and bonding pads, where the first electrode's thickness is ⅓ or less of the insulating layer's thickness, allowing for proper insulating layer formation and preventing defects, with a branch electrode structure and recesses to enhance electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the n-type electrode is made thick to ensure electrical conductivity, then electrical conduction is improved, but the insulating layer cannot be correctly formed and electrical characteristics deteriorate
Solution Approach 1:
The first electrode is divided into multiple segments (first segment, second segment, third segment) with different thicknesses. The first segment has a smaller thickness to allow proper insulating layer formation, while the second and third segments provide adequate thickness for electrical conduction. This segmentation resolves the contradiction by distributing different functional requirements to different parts of the electrode structure.
Solution Approach 2:
Different portions of the first electrode have different thicknesses tailored to local requirements. The region under the second bonding pad has a thinner first segment for insulating layer formation, while other regions have thicker segments for electrical conduction. This local quality variation allows simultaneous satisfaction of both insulating layer formation and electrical conductivity requirements.
2Reliability
If the first electrode thickness is increased to improve electrical conduction, then electrical conductivity is enhanced, but the insulating layer cannot be correctly formed between bonding pads and electrodes
Solution Approach 1:
The first electrode is segmented into multiple portions with varying thicknesses. The first segment has reduced thickness specifically in the region where the insulating layer needs to be formed, enabling proper manufacturing of the insulating layer while maintaining adequate thickness in other segments for electrical conduction.
Solution Approach 2:
The thickness parameter of the first electrode is varied spatially across different regions. By changing the thickness parameter from a uniform value to a graded or segmented distribution, the patent enables both proper insulating layer formation (where thickness is reduced) and adequate electrical conduction (where thickness is maintained or increased).
Data Source
AI summary
A light-emitting device in an embodiment includes a substrate, a light-emitting structure which is disposed on the substrate and includes a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer, first and second electrodes which are respectively connected to the first and second conductive semiconductor layers, first and second bonding pads respectively connected to the first and second electrodes, and an insulating layer disposed between the first bonding pad and the second electrode, and between the second bonding pad and the first electrode. The first thickness of the first electrode may be ⅓ or less of the second thickness of the insulating layer disposed between the second bonding pad and the first electrode.