Micro-LED Support Layer Structure for Crack-Resistant Transfer
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Solution Overview
Problem
Micron-scale LED chips face cracking issues during transfer to the driving backplate due to stress, leading to reduced manufacturing yield in LED display apparatuses.
Innovation Solution
A light-emitting device structure comprising an epitaxial layer with a support layer and insulating layer, where the support layer extends from the first electrode pad to the second electrode pad, providing structural strength and reducing stress-related damage during transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If micron-scale LED chips are used as display sub-pixels, then the display resolution and modernity are improved, but the chips face cracking issues during transfer due to stress, reducing manufacturing yield
Solution Approach 1:
The patent segments the LED chip structure by introducing a support layer that extends beneath the epitaxial layer and connects to the substrate. This segmentation provides mechanical support to the fragile micron-scale chip while maintaining its small size for high-resolution displays, thereby resolving the contradiction between display resolution and chip structural integrity
Solution Approach 2:
The patent employs a composite structure consisting of multiple layers including the epitaxial layer, support layer, insulating layer, and electrode pads. This composite material structure enhances the overall mechanical strength and stress resistance of the micron-scale LED chip, preventing cracking during transfer while maintaining the required display resolution
2Area of moving object
If the chip size and thickness are reduced to micron-scale, then the display density is improved, but the chips become more susceptible to stress-induced cracking during massive transfer
Solution Approach 1:
The patent addresses the strength issue by extending the support layer in the vertical dimension beneath the epitaxial layer and anchoring it to the substrate. This dimensional extension provides mechanical reinforcement without increasing the horizontal chip size, thus maintaining high display density while improving stress resistance during transfer
Solution Approach 2:
The support layer acts as an intermediary element between the fragile epitaxial layer and the substrate. It mediates the stress distribution during chip transfer, protecting the micron-scale chip from cracking while allowing the chip to maintain its small size for high-density displays
3Productivity
If massive transfer of micron-scale LED chips is performed, then the productivity is improved, but the yield rate decreases due to stress-induced cracking
Solution Approach 1:
The support layer serves as a pre-established protective structure that cushions the epitaxial layer against stress during the massive transfer process. This beforehand cushioning enables high-productivity transfer operations while maintaining high bonding yield rates by preventing stress-induced cracking of the micron-scale chips
Data Source
AI summary
A light-emitting device including an epitaxial layer, a support layer, an insulating layer, a first electrode pad, and a second electrode pad is provided. The epitaxial layer includes a first type doped semiconductor layer, a light-emitting layer and a second type doped semiconductor layer, wherein the light-emitting layer is disposed on a partial area of the first type doped semiconductor layer and is between the first type doped semiconductor layer and the second type doped semiconductor layer. The support layer covers the second type doped semiconductor layer while the insulating layer covers the epitaxial layer and the support layer. The first and the second electrode pads are disposed over the insulating layer and electrically connected to the first and the second type doped semiconductor layers, respectively. The support layer extends from a first position below the first electrode pad to a second position below the second electrode pad.