Micro-LED Wafer Transfer for High-Throughput RGB Display Fabrication
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Solution Overview
Problem
The manufacturing of GaN-based light emitting diodes (LEDs) is hindered by the high cost and limited availability of native GaN substrates, and existing display technologies using liquid crystal or organic LED (OLED) displays are inefficient and costly due to the need for multiple components and low electrical-to-optical energy conversion.
Innovation Solution
A method involving selective etching and bonding processes transfers micro-LEDs from donor wafers to a carrier wafer, forming a high-resolution display panel with individually addressable pixels, using a wafer-level process to increase throughput and reduce costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If native GaN substrates are used for LED manufacturing, then crystal quality and defect density are improved, but substrate cost and availability worsen
Solution Approach 1:
The patent introduces a carrier wafer as an intermediary substrate that receives transferred micro-LEDs. This carrier wafer serves as a mediator between the donor wafer (where micro-LEDs are grown) and the final product, enabling the use of cheaper foreign substrates while achieving quality comparable to native substrates through the transfer process
Solution Approach 2:
The patent creates copies of micro-LEDs by growing them on foreign substrates and then transferring them to carrier wafers. This copying approach allows multiple micro-LEDs to be replicated and arranged on the carrier wafer, achieving high-quality LED arrays without requiring expensive native substrates for each device
2Ease of manufacture
If traditional display technologies (LCD or OLED) are used, then manufacturing complexity is reduced, but energy conversion efficiency and performance worsen
Solution Approach 1:
The patent merges multiple micro-LEDs of different colors (red, green, blue) onto a single carrier wafer to form integrated pixels. This combining approach creates high-efficiency display elements that directly convert electrical energy to optical energy with superior efficiency compared to LCD or OLED technologies
Solution Approach 2:
The patent changes the fundamental parameter of energy conversion by using electroluminescent micro-LEDs instead of liquid crystal or organic electroluminescent materials. This parameter change from LCD/OLED conversion mechanisms to micro-LED direct electroluminescence achieves dramatically improved electrical-to-optical energy conversion efficiency
3Productivity
If micro-LEDs are transferred using wafer-level parallel process, then productivity is improved, but process complexity and manufacturing difficulty worsen
Solution Approach 1:
The patent segments the complex transfer process into distinct sequential steps: selective etching to release micro-LEDs, bonding to carrier wafer, and patterning to arrange them in pixel arrays. This segmentation of the overall process into manageable stages enables parallel wafer-level processing while controlling complexity through systematic process decomposition
Solution Approach 2:
The patent performs preliminary actions by pre-growing micro-LEDs on donor wafers with specific patterns and pre-preparing carrier wafers with appropriate structures before the transfer process. This preliminary preparation enables the subsequent parallel transfer to proceed efficiently with standardized procedures, reducing the complexity of real-time decision-making during manufacturing
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 method enables the production of highly efficient, cost-effective, and high-performance micro-LED displays with improved electrical-to-optical energy conversion by transferring and patterning micro-LEDs onto a carrier wafer, overcoming the limitations of native substrate availability and display inefficiencies.
Implementation Method 1
By using a selective etch process such as a photo electrochemical (PEC) etch combined with a bonding process at least a portion of the epitaxial material is transferred to the carrier wafer
Implementation Method 2
By using a selective etch process such as a photo electrochemical (PEC) etch combined with a bonding process at least a portion of the epitaxial material is transferred to the carrier wafer
Implementation Method 3
When a suitable voltage is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence
Data Source
AI summary
Methods for manufacturing LED display panel devices include providing donor wafers having LED die configured to emit different color emissions. At least some of the LED die are selectively transferred from the donor wafers to a carrier wafer such that the carrier wafer is configured with different color emitting LEDs. The different color LEDs may include red-green-blue LEDs to form a RGB display panel.