Micro LED Transfer Patterning to Reduce Active Layer Etching Damage
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Solution Overview
Problem
Current display device fabrication methods face challenges in reducing etching damage to the active layer during the transfer process of micro LEDs, which affects light efficiency.
Innovation Solution
The method involves primary patterning on a growth substrate and secondary patterning on a circuit substrate, using a polyhedral-shaped light-emitting element with a specific cross-sectional shape and insulating layers, and transferring these elements to minimize etching damage and improve light efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If micro LEDs are transferred directly from growth substrate to display panel, then transfer process is simple, but etching damage to active layer occurs and light efficiency decreases
Solution Approach 1:
The transfer process is divided into two separate patterning steps: primary patterning on the growth substrate to form stripe-shaped light-emitting elements, and secondary patterning on the circuit substrate to form island-shaped elements. This segmentation allows each etching step to be optimized independently, reducing cumulative etching damage to the active layer while maintaining manufacturing feasibility.
2Object-affected harmful factors
If primary patterning is performed on growth substrate and secondary patterning on circuit substrate, then etching damage is dispersed and light efficiency improves, but process complexity increases
Solution Approach 1:
The growth substrate serves as an intermediary platform where primary patterning is performed first to create stripe-shaped light-emitting elements. These elements are then transferred to the circuit substrate for secondary patterning. This intermediary step disperses the etching damage across two separate processes rather than concentrating it in one step, protecting the active layer while managing overall process complexity.
3Reliability
If light-emitting elements have polyhedral shape with wider middle portion, then process margin is acquired during transfer, but manufacturing precision requirements increase
Solution Approach 1:
The polyhedral shape with a wider middle portion is formed during the primary patterning step on the growth substrate before transfer. This preliminary formation of the robust polyhedral geometry provides a process margin that accommodates variations during the transfer process. The wider middle section acts as a buffer zone that tolerates alignment and positioning variations, reducing the impact of precision errors during transfer while maintaining the required manufacturing precision for the final island shape.
Data Source
AI summary
The present disclosure provides a display device and a method for fabricating the same. According to one or more embodiments, a display device includes a substrate, pixel electrodes above the substrate, light-emitting elements above the pixel electrodes, extending in a thickness direction of the substrate, and having a polyhedral shape in the thickness direction, a width of a middle portion of the polyhedral shape being greater than a width of an upper portion of the polyhedral shape and greater than a width of a lower portion of the polyhedral shape, and a common electrode above the light-emitting elements.