Reflective Structure with Ascending Refractive Index Dielectric Films
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor reflective structures face challenges in achieving high reflectivity and uniformity, particularly in miniaturized LED displays where the size of individual micro-LEDs ranges from 1 to 10 μm, requiring rigorous planarization processes to meet surface roughness uniformity standards.
Innovation Solution
A reflective structure with a dielectric layer comprising three or more dielectric films stacked in an ascending order of refractive indices, where the refractive index of each film is between 1.47 and 1.8, enhancing total reflectivity and alleviating the need for stringent uniformity requirements, thereby simplifying manufacturing and improving reflectivity across visible light wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional single-layer or two-layer dielectric reflective structures are used, then the manufacturing process is simpler, but the total reflectivity is lower and surface roughness uniformity is difficult to achieve in miniaturized LEDs
Solution Approach 1:
The dielectric layer is segmented into multiple sub-layers (first, second, and third dielectric films) with different refractive indices. This segmentation allows each layer to contribute differently to the overall reflectivity, achieving higher total reflectivity (increased by more than 3%) while managing the complexity through systematic layering rather than a single complex layer.
Solution Approach 2:
Each dielectric film is assigned a specific refractive index within the range of 1.47 to 1.8, with the first film having a lower refractive index than the second, and the second having a lower refractive index than the third. This local quality differentiation optimizes light reflection at each interface, enhancing overall reflectivity while accommodating variations in miniaturized LED structures.
2Manufacturing precision
If miniaturized LED structures with size below 200 microns are used, then the resolution is enhanced, but the surface roughness uniformity becomes difficult to control
Solution Approach 1:
The refractive index of each dielectric film is controlled within a specific range (1.47 to 1.8), and the thickness of each film is optimized to achieve the desired optical performance. By changing these parameters systematically, the patent achieves high reflectivity and improved surface roughness uniformity even in miniaturized LEDs with sizes below 200 microns, reducing the stringency of uniformity requirements.
3Reliability
If the refractive index range of dielectric films is expanded, then the total reflectivity increases, but the material selection and manufacturing complexity increase
Solution Approach 1:
The patent defines a specific refractive index range (1.47 to 1.8) for the dielectric films, which balances optical performance and manufacturability. This parameter optimization allows achieving more than 3% increase in total reflectivity while keeping material selection and fabrication processes manageable through standardized material choices within the specified range.
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 ascending refractive index structure increases total reflectivity by more than 3% compared to conventional designs, making it more flexible and efficient for semiconductor structures, particularly in micro-LED displays, while maintaining high reflectivity and color accuracy.
Implementation Method 1
A reflective structure with a dielectric layer comprising three or more dielectric films stacked in an ascending order of refractive indices, where the refractive index of each film is between 1.47 and 1.8, enhancing total reflectivity
Implementation Method 2
a dielectric layer disposed on the first surface, and has a first dielectric film, a second dielectric film, and a third dielectric film. The first dielectric film is disposed on the first surface. The second dielectric film is disposed on the first dielectric film. The third dielectric film is disposed on the second dielectric film. A refractive index of the first dielectric film is smaller than a refractive index of the second dielectric film, and the refractive index of the second dielectric film is smaller than a refractive index of the third dielectric film
Data Source
AI summary
A method for manufacturing reflective structure is provided. The method includes the operations as follows. A metallization structure is received. A plurality of conductive pads are formed over the metallization structure. A plurality of dielectric stacks are formed over the conductive pads, respectively, wherein the thicknesses of the dielectric stacks are different. The dielectric stacks are isolated by forming a plurality of trenches over a plurality of intervals between each two adjacent dielectric stacks.