Microchip Transfer Head Using Water Droplets for Self-Alignment

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Solution Overview

Problem

Conventional microchip transportation heads face challenges such as mechanical and chemical damage, contamination, and misalignment issues during the transfer of flexible light-emitting diode chips, particularly due to wear, high voltage arcing, and static electricity, which affect the production yield and lifespan of these chips.

Innovation Solution

A transportation head with a head body featuring a pickup region and a dummy region, where only the protruding pins on the pickup region are hydrophilized, and the dummy region is hydrophobized, utilizing a liquid droplet of pure water at room temperature and atmospheric pressure to pick up and transfer microchips via capillary force, avoiding direct contact and minimizing damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a transportation head using an elastomer (PDMS) stamp scheme is used to transfer light-emitting diode chips, then the chips can be transported and transferred to display substrate locations, but the stamp may wear due to reduction in adhesion after repeated uses and the chips may be damaged due to pressure

Engineering Contradiction:

Improvechip transfer capabilityVSAvoidstamp adhesion durability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent introduces a liquid droplet as an intermediary between the transportation head and the light-emitting diode chip. The liquid droplet forms a bridge that enables chip pickup and transfer without direct contact between the stamp and chip, eliminating wear on the stamp while maintaining transfer capability. The liquid mediates the interaction, allowing the chip to be held and transported without mechanical pressure that would cause damage.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If a transportation head using the electrostatic scheme is used to selectively apply input voltage for gripping, then chips can be picked up, but the dielectric layer may be damaged during repeated transportation and chips may be damaged due to high voltage arcing

Engineering Contradiction:

Improveselective chip pickupVSAvoidhigh voltage arcing damage

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the electrostatic gripping mechanism with a liquid droplet-based holding mechanism. Instead of using high voltage to grip the chip, the liquid droplet utilizes surface tension and capillary forces to hold and transport the chip. This substitution eliminates the harmful high voltage arcing while maintaining the ability to selectively pick up and transfer chips.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If direct contact between the transportation head and light-emitting diode chip is made for pickup, then chips can be transferred, but misalignment may occur and chips may be damaged or contaminated

Engineering Contradiction:

Improvechip transfer efficiencyVSAvoidalignment accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The liquid droplet serves as a mediator that enables indirect contact between the transportation head and the chip. The droplet conforms to the chip surface and provides a compliant interface that accommodates minor misalignments. This indirect contact through the liquid intermediary prevents damage and contamination while maintaining transfer efficiency, as the liquid can adapt to slight position variations without causing mechanical stress.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

This solution effectively reduces mechanical and chemical damages, contamination, and misalignment defects by using the capillary force of a pure water droplet for microchip transfer, enabling accurate self-alignment over time due to surface tension, thus enhancing the production process and chip integrity.

Implementation Method 1

a liquid droplet attached to the first protruding pins... utilizing a liquid droplet of pure water at room temperature and atmospheric pressure to pick up and transfer microchips via capillary force

Methodology Applied

Scientific EffectCapillary force: Capillary Action

Implementation Method 2

only the protruding pins on the pickup region are hydrophilized, and the dummy region is hydrophobized

Methodology Applied

Scientific EffectHydrophilization and hydrophobization: Wetting

Implementation Method 3

enabling accurate self-alignment over time due to surface tension

Methodology Applied

Scientific EffectSurface tension: Surface Tension

Data Source

PatentUS11939173B2Transportation head for microchip transfer device, microchip transfer device having same, and transfer method thereby

Publication Date: 2024.03.26 LG DISPLAY CO LTD

AI summary

A transportation head for a microchip transfer device capable of minimizing mechanical and chemical damage to a microchip, a microchip transfer device having same, and a transfer method thereby, and the transportation head includes a head body having a pickup area and a dummy area; a first protruding pin disposed in the pickup area of the head body; and a liquid droplet attached to the first protruding pin.