Micro LED Electrode Pad Layout for Self-Aligned Backplane Bonding
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Solution Overview
Problem
Existing LED display manufacturing processes face challenges in ensuring sufficient mounting margins and self-alignment of micro LEDs during the bonding process, leading to potential failures and reduced integration density.
Innovation Solution
The proposed solution involves a light-emitting diode (LED) design with a specific electrode pad configuration, including a center P-type electrode pad and symmetrically disposed N-type electrode pads, which are arranged diagonally across the LED surface, along with a backplane structure featuring bonding pads and molds for self-alignment, ensuring maximum distance between electrode pads for improved mounting stability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If micro LEDs are transferred to a panel substrate for LED display manufacturing, then the display can be constructed with LED pixels, but sufficient mounting margin (bonding margin) cannot be ensured during the bonding process
Solution Approach 1:
The patent applies preliminary action by pre-configuring the electrode pad layout on the LED chip before bonding. The electrode pads are positioned at specific locations (including corner pads and edge pads) that are determined in advance to provide adequate bonding margins. This pre-planned electrode arrangement ensures that when the LED chip is transferred to the panel substrate, sufficient mounting margin is available without requiring adjustments during the actual bonding process.
2Quantity of substance
If micro LEDs are densely integrated on the panel substrate, then integration density increases, but self-alignment of LEDs during mounting becomes difficult
Solution Approach 1:
The patent implements self-service through self-aligned electrode pad configurations that guide the LED chip positioning during bonding. The electrode pads are arranged in specific patterns (such as symmetric arrangements or patterns matching the substrate bonding pads) that enable the LED chip to self-align with the substrate during the bonding process. This eliminates the need for complex external alignment mechanisms and maintains high positioning precision even as integration density increases.
3Reliability
If electrode pads are positioned to maximize mounting stability, then bonding reliability improves, but the area available for other functional elements is reduced
Solution Approach 1:
The patent applies dimensionality change by utilizing the perimeter and corner regions of the LED chip for electrode pad placement rather than only the central area. By positioning electrode pads at corners and along edges, the design effectively uses the two-dimensional boundary space, which does not interfere with the central active area of the chip. This approach maintains adequate bonding margins for reliability while preserving maximum available area in the chip center for light-emitting structures and other functional elements.
Data Source
AI summary
A light-emitting diode (LED) includes a first semiconductor layer, an active layer, and a second semiconductor layer that are sequentially stacked, and includes a first electrode pad, a second electrode pad and a third electrode pad disposed on the second semiconductor layer in a direction from a corner of the second semiconductor layer to an opposite corner of the second semiconductor layer. An LED includes a first electrode pad disposed at a center of the LED and in contact with a P-type semiconductor layer and a second electrode pad in contact with an N-type semiconductor layer, wherein the second electrode pad is disposed a maximum distance away from the first electrode pad on the same surface.