Micro LED Interconnect Structure Without Mass Transfer Bonding
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Solution Overview
Problem
Conventional Micro LED processes require a mass transfer step to bond individual LED dies onto a substrate, resulting in low transfer efficiency and yield, which hinders mass production and repair of defective pixels.
Innovation Solution
A Micro LED structure is formed directly on a substrate with a driver circuit without mass transfer, using a substrate with metal interconnects and dielectric layers, and conductive lines connecting the LED dies to the driver circuit, allowing for soft repair of defective pixels and improved luminous efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mass transfer process is used to bond LED dies onto substrate, then LED pixels can be formed on driver circuit substrate, but transfer efficiency is low and yield is poor
Solution Approach 1:
The patent applies preliminary action by pre-forming conductive lines and metal interconnects on the substrate before bonding LED dies. The substrate is prepared with driver circuits, dielectric layers, and conductive pathways in advance, so that when LED dies are bonded, electrical connections are already in place. This eliminates the need for complex post-bonding alignment and connection processes, significantly improving transfer efficiency and yield.
Solution Approach 2:
The substrate serves multiple functions: it acts as the driver circuit board, the bonding target for LED dies, and the electrical connection network all in one. The metal interconnects and conductive lines are integrated into the substrate structure, allowing the same substrate to provide mechanical support, electrical connectivity, and circuit control functions simultaneously.
2Ease of repair
If mass transfer process is used to bond LED dies onto substrate, then LED pixels can be formed on driver circuit substrate, but repair of defective pixels is difficult
Solution Approach 1:
The patent divides the display into individually addressable LED die segments, each with its own conductive lines for control. This segmentation allows defective pixels or small groups of pixels to be identified and replaced independently without affecting the entire display. Individual LED dies can be removed and replaced by re-bonding to the same substrate with existing conductive connections.
3Productivity
If conventional Micro LED process is used, then individual LED dies can be bonded onto substrate, but production cycle is extended and mass production is hindered
Solution Approach 1:
The patent merges multiple separate processes into a single integrated workflow. Substrate preparation (forming driver circuits and conductive lines), LED die bonding, and electrical connection are combined into one continuous process. The conductive lines are formed as part of the substrate fabrication process rather than as a separate post-bonding step, reducing total production time and enabling mass production.
Data Source
AI summary
A light-emitting diode (LED) structure is provided in the present invention, including a substrate, a dielectric layer on the substrate, metal interconnects in the dielectric layer, LED dies on the dielectric layer, wherein each LED die is provided with a front side and a back side, the back side is bonded with the dielectric layer, and the cathode and anode are on the front side of LED die, and bonding lines connecting the cathode and anode on the front side of LED die to the metal interconnects respectively.