Wet Chip Transfer Alignment for Empty Groove Refill in Micro-LEDs

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Solution Overview

Problem

The productivity of micro LED display devices decreases as the size of micro LEDs decreases and the size of displays increases, due to inefficiencies in the pick-and-place method used for transferring micro-semiconductor chips to substrates.

Innovation Solution

A chip wet transfer apparatus is developed, utilizing a wet method to align micro-semiconductor chips on a transfer substrate with grooves, involving a first and second chip supply module and alignment module, along with an inspection module and controller to optimize chip placement and address empty grooves, enhancing transfer efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the pick-and-place method is used to transfer micro LEDs, then the transfer process can be performed, but productivity is reduced as the size of micro LED decreases and the size of display increases

Engineering Contradiction:
Improvetransfer rateVSAvoidtransfer process complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent uses liquid suspension to transport micro-LEDs from the source substrate to the target substrate. The liquid medium carries the micro-LEDs through capillary action and flow control, enabling high-speed transfer without mechanical picking and placing. This hydraulic approach replaces the mechanical pick-and-place system with a fluid-based transport system that achieves higher productivity.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent replaces the mechanical pick-and-place system with a wet chemical/liquid-based system. Instead of using mechanical grippers and robots to pick and place each micro-LED, the invention uses liquid suspension that flows over the substrates to transport and deposit micro-LEDs automatically, eliminating the complexity of mechanical positioning systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Quantity of substance

If a large volume of suspension is used to fill all grooves, then all grooves can be filled, but time and resource waste increase

Engineering Contradiction:
Improvechip filling completenessVSAvoidtransfer time
Core Design Contradiction:
Quantity of substanceVSLoss of time

Solution Approach 1:

The patent performs preliminary filling of grooves with micro-LEDs in suspension, then uses a drying step to fix the chips in place. After drying, any empty grooves are identified and selectively refilled with additional suspension. This two-stage approach ensures complete filling while minimizing the total volume of suspension needed and reducing overall transfer time.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent employs a periodic process where suspension is applied, dried, inspected, and selectively reapplied to empty grooves. This cyclic approach allows the system to efficiently fill grooves in batches rather than requiring all grooves to be filled simultaneously, reducing the volume of suspension needed at any one time and optimizing transfer time.

Inventive Principle:
Principle #19Periodic action

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 apparatus significantly increases the transfer rate and yield of micro-semiconductor chips by aligning a large number initially and then selectively placing smaller amounts in empty grooves, improving the overall efficiency of micro LED display manufacturing.

Implementation Method 1

a first suspension including the plurality of micro-semiconductor chips and a liquid

Methodology Applied
Scientific EffectSuspension: Suspension

Implementation Method 2

a first drying module configured to dry the first suspension on the transfer substrate

Methodology Applied
Scientific EffectDrying:

Data Source

PatentEP4303938A1Chip wet transfer apparatus
Publication Date: 2024.01.10 SAMSUNG ELECTRONICS CO LTD
  • EP4303938A1 patent drawingFigure 1
  • EP4303938A1 patent drawingFigure 2
  • EP4303938A1 patent drawingFigure 3

AI summary

A chip wet transfer apparatus includes a first chip supply module configured to supply a large amount of micro-semiconductor chips to a transfer substrate, a first chip alignment module configured to align the large amount of micro-semiconductor chips in a plurality of grooves, a second chip supply module configured to supply a small amount of micro-semiconductor chips, and a second chip alignment module configured to align the small amount of micro-semiconductor chips.