Micro-LED Via Contact Layout for Higher Display Yield
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Solution Overview
Problem
The yield rate decreases when manufacturing micro-LED display apparatuses due to the decrease in size of micro-LEDs and increase in display size, and there is a need for high-speed transfer and reduced repair rates.
Innovation Solution
A micro-LED display apparatus design with an insulating layer thicker than the micro-LEDs, electrical contacts with a thickness corresponding to the distance between the insulating layer and micro-LEDs, and a pitch less than the width of the micro-LEDs, arranged in patterns such as dotted, stripe, or concentric-circular, ensuring consistent electrical connection and reducing the need for repairs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the micro-LED size is decreased to increase display resolution, then the display quality is improved, but the yield rate decreases due to manufacturing difficulties
Solution Approach 1:
The invention divides the electrical connection structure into multiple components: a lower electrode on the substrate, an insulating layer, via patterns etched through the insulating layer, and upper electrodes. This segmentation allows each component to be optimized independently, with the via patterns providing precise alignment features that accommodate variations in micro-LED positioning, thereby maintaining high yield rates even as micro-LED sizes decrease for higher resolution displays.
2Area of stationary object
If the display size is increased while maintaining micro-LED size, then the display area is expanded, but the yield rate decreases due to transfer difficulties
Solution Approach 1:
The invention prepares the substrate with a complete electrical connection structure including insulating layers and via patterns before transferring the micro-LEDs. The via patterns are pre-formed with precise geometric features that serve as alignment guides. This preliminary preparation ensures that when micro-LEDs are transferred (regardless of display size), they can be accurately positioned and connected, maintaining high yield rates across large display areas.
3Manufacturing precision
If the pitch of electrical contacts is decreased to improve connection density, then the electrical connection precision is improved, but the risk of short-circuits increases
Solution Approach 1:
The insulating layer serves as an intermediary barrier between the lower electrode and the upper electrodes. The via patterns etched through this insulating layer create controlled pathways for electrical connection. This intermediary structure allows dense pitch arrangements because the insulating layer prevents unintended short-circuits between adjacent contacts, while the precise via patterns ensure reliable electrical connection when needed.
4Object-affected harmful factors
If the thickness of the insulating layer is increased to prevent short-circuits, then the electrical isolation is improved, but the distance for electrical connection increases
Solution Approach 1:
The invention transitions from a planar electrical connection approach to a three-dimensional structure with via patterns etched through the insulating layer. The via patterns create vertical connection pathways that penetrate the insulating layer, allowing electrical connection across the full thickness of the insulator. This dimensional change enables the use of thicker insulating layers for better short-circuit prevention while maintaining effective electrical connection through the via pathways.
Data Source
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Figure 3A~3B
AI summary
The present disclosure provides a micro-light-emitting diode display apparatus and a method of manufacturing the same. Provided is a micro-light-emitting diode (LED) display apparatus including a plurality of pixels, the micro-LED display apparatus including a driving circuit substrate, a first electrode provided on the driving circuit substrate, one or more micro-light-emitting diodes (LEDs) provided on the first electrode, an insulating layer provided on the one or more micro-LEDs, a via pattern provided in the insulating layer, electrical contacts provided in the via pattern, and a second electrode provided on the electrical contacts, wherein the via pattern exposes a portion of the one or more micro-LEDs.