MicroLED Carrier Post Layout for High-Utilization Mass Transfer
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Solution Overview
Problem
Existing microLED technologies face challenges in achieving high wafer utilization and efficient mass transfer with high yield and speed, particularly in direct-view displays, and are not compatible with various transfer technologies and LED designs.
Innovation Solution
A method involving carrier posts positioned within the areal extent of microLEDs, forming the sole attachment to a carrier substrate, with controlled tensile strength interfaces, allowing for simultaneous mass transfer to other substrates or elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional attachment methods are used to connect microLEDs to carrier substrate, then mechanical strength is improved, but device complexity and manufacturing difficulty increase due to multiple attachment points and structures
Solution Approach 1:
The patent extracts the attachment function from the carrier substrate itself and relocates it to separate carrier posts. Each microLED is attached to its own individual carrier post, which then connects to the carrier substrate. This separation simplifies the overall attachment structure while maintaining mechanical strength, as the complexity is isolated to the posts rather than the entire substrate interface.
Solution Approach 2:
The attachment system is segmented into discrete carrier posts, with each post handling the attachment of a single microLED or small group of microLEDs. This segmentation allows for simplified individual attachment points while maintaining overall structural integrity through the array of posts distributed across the carrier substrate.
2Productivity
If microLEDs are closely spaced to increase wafer utilization, then productivity is improved, but manufacturing precision requirements increase due to reduced device separation
Solution Approach 1:
Carrier posts serve as intermediary elements between microLEDs and the carrier substrate, providing mechanical support and electrical connection. This intermediary structure enables closer spacing of microLEDs on the wafer while maintaining proper device separation and alignment, as the posts can be precisely positioned and fabricated with controlled dimensions independent of the microLED spacing.
3Stability of the object's composition
If multiple attachment points are used between microLEDs and carrier substrate, then mechanical stability is improved, but transfer difficulty increases due to inability to easily separate devices
Solution Approach 1:
The attachment function is extracted from the carrier substrate and placed in separate carrier posts. This allows the microLEDs to be firmly attached during manufacturing (providing mechanical stability) while enabling easy separation during transfer, as the posts can be designed to detach cleanly from the substrate or be selectively removed without damaging the microLEDs.
Solution Approach 2:
By segmenting the attachment system into individual posts rather than a continuous attachment layer, each post can be independently managed during transfer operations. This segmentation allows for controlled separation where posts can be released one at a time or in groups, maintaining stability during manufacturing but enabling flexible transfer operations.
4Manufacturing precision
If carrier posts are positioned outside the areal extent of microLEDs, then device separation is improved, but wafer utilization decreases due to increased spacing requirements
Solution Approach 1:
Carrier posts are positioned within the areal extent of microLEDs in the planar dimension, utilizing the vertical dimension for the post structure itself. This allows the posts to occupy the same footprint as the microLEDs without increasing lateral spacing, thereby maintaining high wafer utilization while providing sufficient device separation through the vertical positioning and dimensional separation of the post structure from the LED active area.
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
Enhances wafer utilization and enables high-yield, high-speed mass transfer of microLEDs compatible with diverse transfer technologies and designs, reducing costs and improving display feasibility.
Implementation Method 1
depositing one or more polymer precursors onto a multitude of semiconductor light-emitting devices
Implementation Method 2
After their deposition, the polymer precursor(s) are cured to form a solid polymer layer
Data Source
AI summary
A light-emitting apparatus includes a carrier substrate, an array of light-emitting devices on the carrier substrate, and carrier posts connecting the light-emitting devices to the carrier substrate spaced apart from the carrier substrate. The carrier post forms the only attachment between each light-emitting device and the carrier substrate, is positioned within the areal extent of the light-emitting device, and is attached to the light-emitting device at an attachment area thereof that occupies only a fractional portion of the areal extent of the light-emitting device. A transfer substrate can adhere to the light-emitting devices and then be separated from the carrier substrate with the light-emitting devices adhered thereto. The light-emitting devices can then be attached to a backplane, interconnect layer, or circuit board and the transfer layer removed leaving the behind the attached light emitting devices.