Inclined Contact Electrode Structure for Uniform LED Protective Layers
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Solution Overview
Problem
The reliability of semiconductor light-emitting elements is compromised due to a reduced film thickness of the dielectric protective layer at the edges of electrodes, leading to inadequate covering properties and potential conductivity issues.
Innovation Solution
A semiconductor light-emitting element design featuring contact electrodes with inclined portions and current diffusion layers, where the width of these inclined portions is significantly larger than the thickness of the electrode, ensuring a uniform film thickness of protective layers and enhanced sealing properties, and a method of manufacturing involving resist layers with undercut shapes to facilitate uniform deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dielectric protective layer is provided on the electrode of the semiconductor light-emitting element, then the electrode is protected, but the film thickness is reduced at the portion covering the edge of the electrode, leading to reduced covering property and reliability
Solution Approach 1:
The contact electrode is designed with an asymmetric thickness profile, featuring a first inclined portion where the thickness gradually decreases toward the edge, and a second inclined portion where the thickness gradually increases. This asymmetric design allows the protective layer to be deposited uniformly across the entire surface, including edges, eliminating the thickness reduction problem at electrode edges while maintaining electrode protection functionality
Solution Approach 2:
The invention transitions from a conventional planar electrode design to a three-dimensional inclined electrode structure. By introducing gradual thickness transitions in the vertical dimension, the electrode surface becomes more accommodating to uniform protective layer deposition, allowing the dielectric layer to maintain consistent thickness even at edge regions
2Ease of manufacture
If the contact electrode has a uniform thickness, then the manufacturing is simpler, but the protective layer film thickness is reduced at the edge portions
Solution Approach 1:
The inclined portions of the contact electrode are formed in advance during the electrode fabrication process, before the protective layer is deposited. This preliminary shaping of the electrode surface ensures that when the protective layer is subsequently deposited, it can conform uniformly to the entire surface including edge regions, thereby maintaining both manufacturing simplicity and protective layer integrity
Solution Approach 2:
The contact electrode is designed with locally varied thickness characteristics - the first inclined portion has decreasing thickness toward the edge, while the second inclined portion has increasing thickness. This local quality variation in the electrode structure enables the protective layer to achieve uniform thickness distribution across different regions, improving covering property without significantly complicating the overall manufacturing process
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
The design improves the reliability and moisture resistance of semiconductor light-emitting elements by maintaining uniform film thickness and conductivity across the protective layers, even when exposed to external environments.
Implementation Method 1
depositing an electrode layer in the first opening by using the first resist as a mask
Data Source
AI summary
A semiconductor light-emitting element includes a contact electrode in contact with an upper surface of a semiconductor layer, a protective layer covering the contact electrode, and a pad electrode provided on the protective layer. The contact electrode includes a first inclined portion in which an upper surface of the contact electrode is inclined such that the thickness of the contact electrode decreases toward an edge of the contact electrode. The width of the first inclined portion in a direction in which the edge of the contact electrode extends and in a predetermined direction orthogonal to a thickness direction of the contact electrode is 10 times or more the thickness of a portion of the contact electrode that is different from the first inclined portion.