Substrate Chuck Clamping for MicroLED Self-Assembly Warpage Control

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Solution Overview

Problem

Current methods for manufacturing large-screen displays using microLEDs face challenges in transferring and assembling semiconductor light-emitting diodes, including low success rates, damage during self-assembly, and warpage of substrates, which affect the reliability and efficiency of the process.

Innovation Solution

A substrate chuck system that allows for the submersion of substrates in a fluid, utilizing a combination of frames, clamps, and sensors to apply controlled pressure and correct warpage, enabling the self-assembly of microLEDs with high reliability and efficiency by using a magnetic field and electric field for precise positioning and assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If self-assembly method is used for transferring microLEDs, then productivity is improved, but reliability deteriorates due to damage during self-assembly

Engineering Contradiction:
Improveassembly speedVSAvoiddamage prevention
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

A buffer part is disposed between the auxiliary clamp and the second frame to prevent direct contact. This buffer part acts as a cushion that absorbs excessive force during the self-assembly process, protecting the microLEDs from damage while still allowing the auxiliary clamp to apply necessary pressing force through the second frame to the substrate.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Productivity

If substrate area is increased for large-screen displays, then productivity is improved, but manufacturing precision deteriorates due to warpage

Engineering Contradiction:
Improvedisplay areaVSAvoidwarpage control
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The auxiliary clamp is configured to press the second frame at specific locations (edges or corners of the substrate) rather than uniformly across the entire substrate. This localized pressing applies counteracting force precisely where warpage occurs due to buoyancy, correcting the deformation without interfering with the overall self-assembly process on the large-area substrate.

Inventive Principle:
Principle #3Local quality

3Reliability

If auxiliary clamp is added to increase clamping force, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improveclamping stabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The auxiliary clamp serves multiple functions: it presses the second frame toward the substrate to increase clamping force, corrects substrate warpage through localized pressing, and prevents damage to microLEDs during self-assembly by using a buffer part. This multi-functionality justifies the added component by providing several critical functions with a single device element.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Enables the high-yield, low-cost assembly of microLEDs on large-area substrates, preventing damage during self-assembly and maintaining reliability even with increased substrate area, by ensuring uniform magnetic field formation and correcting warpage, thus enhancing the manufacturing process for large-screen displays.

Implementation Method 1

a frame moving part configured to transfer the second frame such that the second frame presses the substrate while the substrate is disposed between the first and second frames, and an auxiliary clamp configured to additionally press the second frame toward the substrate

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

enabling the self-assembly of microLEDs with high reliability and efficiency by using a magnetic field and electric field for precise positioning and assembly

Methodology Applied
Scientific EffectMagnetic Field: Magnetic Field

Implementation Method 3

enabling the self-assembly of microLEDs with high reliability and efficiency by using a magnetic field and electric field for precise positioning and assembly

Methodology Applied
Scientific EffectElectric Field: Electric Field

Data Source

PatentEP4131352B1Substrate chuck for self-assembling semiconductor light emitting diodes
Publication Date: 2024.06.12 LG ELECTRONICS INC
  • EP4131352B1 patent drawingFigure 1
  • EP4131352B1 patent drawingFigure 2
  • EP4131352B1 patent drawingFigure 3~4

AI summary

The present disclosure relates to a method for manufacturing a display device, and one particular implementation relates to a substrate chuck for self-assembling micro LEDs. The substrate chuck may include a first frame having a hole at a central portion thereof, a second frame having a hole at a central portion thereof and disposed to overlap the first frame, a frame moving part configured to transfer the second frame such that the second frame presses the substrate while the substrate is disposed between the first and second frames, and an auxiliary clamp configured to additionally press the second frame toward the substrate while the second frame is pressing the substrate.