Micro-LED Display Bonding Without Alignment for Fewer Pixel Defects
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Solution Overview
Problem
Current micro-LED micro-display manufacturing methods, such as mass transfer and flip-chip bonding, face low yield and high costs, and require precise alignment, leading to pixel defects and difficulties in meeting the requirements for mass production of high-resolution micro-display chips suitable for AR applications.
Innovation Solution
A manufacturing process involving a driving backplate with reserved windows and metal pads, isolation columns, alignment-free lamination of an LED epitaxial wafer, and subsequent exposure and development to form LED light-emitting structures, using conductive solders and insulation layers to create stable LED units embedded in conductive solders, allowing for a simpler and more reliable process with reduced pixel defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mass transfer and flip-chip bonding methods are used for Micro-LED manufacturing, then LED transfer capability is achieved, but production yield is low and manufacturing cost is high
Solution Approach 1:
The patent divides the manufacturing process into distinct stages: forming isolation columns to define chip regions, selective removal of LED epitaxial layers in these regions, and separate handling of LED structures from substrate. This segmentation enables parallel processing and eliminates the need for complex alignment and transfer operations, thereby improving yield and reducing manufacturing complexity
Solution Approach 2:
The patent performs preliminary actions by pre-forming isolation columns on the substrate before growing the LED epitaxial layer, and pre-defining chip regions through selective removal patterns. These preliminary structures guide subsequent processing steps and eliminate the need for precise alignment during assembly, simplifying the overall manufacturing process
2Manufacturing precision
If precise alignment lamination is performed on matrix substrate and LED epitaxial substrate, then LED positioning accuracy is improved, but pixel defects increase due to alignment requirements
Solution Approach 1:
The patent segments the LED epitaxial structure into independent chip regions defined by isolation columns, with each region processed separately. This segmentation eliminates the need for alignment between large substrate areas, as each chip region is self-contained and can be independently formed and transferred without reference to adjacent regions
Solution Approach 2:
The patent introduces conductive solder as an intermediary material between the LED chip regions and the matrix substrate. The solder serves as both a bonding agent and a positioning medium, allowing LED structures to be embedded in the solder without requiring precise alignment, thereby eliminating alignment-induced pixel defects
3Adaptability or versatility
If AM driving circuits are manufactured on Si wafer substrate, then circuit integration is achieved, but manufacturing cost increases
Solution Approach 1:
The patent merges the LED light-emitting structures with the driving circuit substrate by directly forming LED chip regions on the same Si wafer substrate that contains the AM driving circuits. This integration eliminates the need for separate substrate processing and assembly steps, reducing manufacturing complexity and cost while maintaining full circuit integration capability
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 process enables the production of ultra-high-resolution micro-display screens with low technological difficulty, low costs, and improved reliability and stability by embedding LED units into conductive solders, enhancing soldering adhesion and package stability.
Implementation Method 1
a multi-layer semiconductor functional material grown on the substrate
Implementation Method 2
arranging conductive solders in the plurality of chip regions
Implementation Method 3
performing exposure and development on the LED epitaxial wafer to enable the chip regions to form a plurality of LED light-emitting structures
Data Source
AI summary
An ultra-high-resolution micro-display screen and a manufacturing process therefor. In the process, multiple LED light-emitting structures are formed by means of pre-arranging isolation columns and a conductive solder on a drive backplate, performing alignment-free pressing on the driving backplate (10) and an LED epitaxial wafer, and performing exposure and development on the LED epitaxial wafer. According to the method, accurate alignment does not need to be performed, and there are few pixel defects. LED units of a micro-display screen are embedded into the conductive solder, such that a high soldering adhesion is achieved, and the reliability and stability of the display screen can be improved.