Micro Chip Transfer Substrate for Fluid Self-Alignment Precision
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Solution Overview
Problem
The productivity of micro LED transfer methods is reduced as micro LED sizes decrease and display sizes increase, making it difficult to effectively arrange micro semiconductor chips on large-area substrates.
Innovation Solution
A micro semiconductor chip transferring substrate with a mold featuring recesses and a surface energy reduction pattern, including convex patterns, allows for easy alignment of micro semiconductor chips using fluid self-alignment, reducing surface energy and preventing chips from adhering to the wrong positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pick and place method is used for transferring micro LEDs, then micro LEDs can be transferred individually, but productivity is reduced as micro LED sizes decrease and display sizes increase
Solution Approach 1:
The patent employs fluid self-alignment where micro semiconductor chips are carried by a fluid into recesses on the transferring substrate. The fluid's surface tension and capillary action automatically guide the chips to their correct positions without requiring complex mechanical positioning systems, enabling high productivity while maintaining precise alignment even as chip sizes decrease.
Solution Approach 2:
The transferring substrate is divided into multiple recesses, each designed to receive and hold a single micro semiconductor chip. This segmentation allows parallel processing of multiple chips simultaneously, dramatically increasing productivity compared to sequential pick-and-place methods, while each recess ensures precise positioning of individual chips.
2Manufacturing precision
If micro LED sizes are reduced to increase display resolution, then display quality improves, but alignment precision becomes more difficult to achieve
Solution Approach 1:
The fluid self-alignment mechanism automatically positions micro semiconductor chips into recesses using surface tension and capillary forces. This self-aligning property eliminates the need for complex mechanical positioning systems, maintaining high alignment precision even for sub-100 micrometer chips while keeping the transfer process relatively simple.
Solution Approach 2:
The patent changes the physical parameters of the interface between chip and substrate by introducing a fluid medium. The fluid's surface tension and viscosity parameters enable automatic alignment of micro chips, achieving high precision without increasing device complexity. The recess depth and width parameters are also optimized to work with the fluid's properties.
3Manufacturing precision
If conventional transfer substrates are used without surface energy reduction patterns, then manufacturing process is simpler, but chips adhere to wrong positions reducing transfer accuracy
Solution Approach 1:
The transferring substrate has different surface properties in different regions: the recess areas have high surface energy to hold chips during transfer, while the flat areas between recesses have reduced surface energy to prevent unwanted adhesion. This local differentiation of surface quality ensures chips are held only at correct positions, improving transfer accuracy without requiring complex external control systems.
Solution Approach 2:
The patent converts the potentially harmful effect of surface adhesion (which could cause chips to stick anywhere on the substrate) into a beneficial selective adhesion mechanism. By creating surface energy reduction patterns, the substrate now uses adhesion forces beneficially - strong adhesion in recesses for holding chips, and weak adhesion on flat areas for preventing misplacement, thereby improving transfer accuracy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The substrate enables efficient alignment of micro semiconductor chips within recesses, facilitating the production of large-area display devices with high manufacturing yield and precision.
Implementation Method 1
a surface energy reduction pattern formed in region between the plurality of recesses, on the upper surface
Implementation Method 2
The convex patterns may be made of metal material
Data Source
AI summary
According to an aspect of an embodiment, provided is a micro semiconductor chip transferring substrate including: a mold including a plurality of recesses formed to be recessed in a certain depth from an upper surface; and a surface energy reduction pattern formed in region between the plurality of recesses, on the upper surface, the surface energy reduction pattern including a plurality of uneven patterns. When the micro semiconductor chips are aligned by a wet alignment method, by such surface energy reduction pattern, sliding of the micro semiconductor chips toward the inside of the recesses may be improved.