Hybrid Bonding of Micro-LED Arrays for Easier Testing
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Solution Overview
Problem
Current technologies face challenges in reliably and efficiently assembling microLED devices due to their small size and complex electrical testing requirements.
Innovation Solution
The development of micro-light emitting diode (uLED) devices utilizing hybrid bonding techniques, which combine metal-to-metal and dielectric-to-dielectric bonds between a source wafer and a target wafer, to ensure reliable electrical communication and assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If microLED devices are miniaturized to achieve high density displays, then display resolution and compactness are improved, but handling and electrical testing become more difficult
Solution Approach 1:
The patent combines multiple microLED devices onto a single carrier substrate, creating an array structure. This merging approach allows handling and testing of multiple devices simultaneously rather than individually, resolving the difficulty of operating on miniaturized components.
Solution Approach 2:
The patent introduces a carrier substrate as an intermediary platform that holds multiple microLED devices. This mediator enables easier handling, positioning, and electrical testing by providing a standardized interface between the small microLEDs and testing equipment.
2Reliability
If hybrid bonding is used to achieve reliable electrical connectivity, then assembly reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent divides the bonding process into two separate stages: first forming metal-to-metal bonds between contact pads, then forming dielectric-to-dielectric bonds between insulating layers. This segmentation of the bonding process makes the complex hybrid bonding procedure more manageable and manufacturable.
Solution Approach 2:
The patent performs preliminary preparation of bonding surfaces including forming contact pads, applying dielectric materials, and creating appropriate surface finishes before the actual bonding step. These preliminary actions ensure reliable electrical connectivity while organizing the complex process into preparatory and execution phases.
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 approach enables efficient assembly and reliable electrical connectivity of microLED devices, addressing the challenges of handling and testing micro-scaled arrays, and supporting applications such as augmented reality/virtual reality systems.
Implementation Method 1
semiconductor light-emitting devices or optical power emitting devices (such as devices that emit ultraviolet (UV) or infrared (IR) optical power), including light emitting diodes
Implementation Method 2
The stack grown on the growth substrate typically includes one or more n-type layers doped with, for example, Si, formed over the substrate, a light emitting or active region formed over the n-type layer or layers, and one or more p-type layers doped with, for example, Mg, formed over the active region
Data Source
AI summary
Micro-light emitting diode (uLED) devices comprise: a source wafer comprising a uLED die bonded to a target wafer. Wafer n-contacts are directly bonded to a plurality of die n-contacts; wafer p-contacts are directly bonded to die p-contacts; and wafer dielectric material is directly bonded to die dielectric material; the wafer dielectric material isolates the wafer n-contacts and the wafer p-contacts.