Beam-Assisted LED Mass Transfer Using KGD Data
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Solution Overview
Problem
Current micro-LED manufacturing methods, such as pick and place, face limitations in throughput and yield due to their inability to effectively utilize Known Good Die (KGD) data for functional LED placement, leading to high error rates and extensive post-transfer repair requirements, making them impractical for commercially competitive production.
Innovation Solution
The Beam-Addressed Release (BAR) mass-transfer method uses a laser beam to rapidly release LED devices from a source substrate to a target substrate based on KGD data, allowing for high-speed, accurate placement and avoiding non-functional LEDs, thereby improving throughput and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pick and place methods are used for micro-LED transfer, then manufacturing process is simple, but throughput is limited and error rate is high
Solution Approach 1:
The patent applies preliminary action by pre-sorting LED devices into known good die (KGD) and non-functional categories before the transfer process. Functional testing is performed on the source substrate to identify KGD devices, and this information is stored in a data structure. During transfer, only KGD devices are selected for placement, eliminating post-transfer repair needs and achieving near 100% transfer yield without compromising throughput.
Solution Approach 2:
The patent implements feedback by using functional test results from the source substrate to guide the transfer process. The system reads KGD data, compares it with target substrate requirements, and dynamically selects which devices to transfer. This closed-loop approach ensures that only functional devices are placed, resolving the contradiction between high throughput and high reliability.
2Productivity
If all LED devices are transferred without functional testing, then transfer speed is high, but post-transfer repair requirements increase
Solution Approach 1:
The patent performs functional testing and device classification before the transfer process, creating a data structure that identifies KGD devices. This preliminary action enables the transfer system to selectively place only functional devices, eliminating the need for post-transfer repair while maintaining high transfer speed. The pre-screening occurs during the transfer operation itself, not as a separate step.
Solution Approach 2:
The patent extracts functional test information from the manufacturing process and uses it to guide device selection during transfer. By separating functional devices from non-functional ones through preliminary testing and using this information to select only KGD devices for transfer, the system eliminates defective devices from the transfer process entirely, avoiding post-transfer repair requirements.
3Manufacturing precision
If KGD data is utilized for selective placement, then transfer accuracy improves, but process complexity increases
Solution Approach 1:
The patent performs preliminary functional testing and creates a data structure containing KGD information before the transfer process. This pre-prepared data enables rapid decision-making during transfer without adding significant complexity, as the system simply queries the existing data structure to determine which devices to place, achieving high placement accuracy through straightforward data lookup and comparison.
Solution Approach 2:
The patent uses a digital copy of functional test results (KGD data) to guide the physical transfer process. Instead of performing real-time functional testing during transfer, the system uses pre-captured functional information in digital form, simplifying the transfer process while maintaining high placement accuracy. The digital data structure serves as a blueprint for selective device placement.
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 BAR method enables the population of KGD LED devices at rates exceeding 100-250 million per hour with virtually no errors, making it compatible with high-volume manufacturing lines and reducing the need for costly repairs.
Implementation Method 1
A mass-transfer apparatus utilizes a beam induced release mechanism to release a plurality of light emitting diode (LED) devices from a source substrate to a target substrate
Data Source
AI summary
Embodiments relate to mass-transfer methods useful for fabricating products containing Light Emitting Diode (LED) structures. LED arrays are transferred from a source substrate to a target substrate by beam-assisted release (BAR) of a plurality of LED devices in a high-speed flexible manner. The BAR mass-transfer approach is also able to utilize a Known Good Die (KGD) data file of the source substrate to transfer only functionally good die and avoid rework and yield losses.