MicroLED Adhesive Film Assembly for Batch Transfer Bonding

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Solution Overview

Problem

The inefficient transfer process of micro-light-emitting diode (MicroLED) chips in mass production, particularly due to excessive thermal transfer leading to bonding failures, hampers production efficiency and increases production time.

Innovation Solution

A light-emitting assembly with a semiconductor layer sequence and electrical contact layers, supported by a wafer-based adhesive film that allows for regular arrangement and batch transfer of MicroLEDs onto a substrate circuit, reducing bonding failures and improving production efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional surface mounting machine is used for transfer, then transfer capability is achieved, but production time increases to 1 month for 6 million chips

Engineering Contradiction:
Improvetransfer speedVSAvoidtransfer cycle time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The transfer process is segmented into two distinct stages: first, batch transfer of multiple MicroLED chips onto a temporary support substrate; second, collective transfer of the entire support substrate with all chips to the final circuit board. This segmentation eliminates repeated pick-and-place operations and enables parallel processing, reducing the transfer cycle from 1 month to a much shorter duration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The support substrate is prepared in advance with adhesive films at predetermined positions before chip transfer. This preliminary preparation of the support substrate with pre-positioned adhesive areas allows for rapid batch attachment of multiple chips in a single operation, dramatically improving transfer efficiency compared to individual chip placement.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If pick and place process is used, then chip transfer is achieved, but thermal change and pressure change cause bonding failures

Engineering Contradiction:
Improvetransfer efficiencyVSAvoidbonding success rate
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

Multiple chip transfer operations are merged into a single batch process. Instead of transferring chips one by one with repeated thermal and pressure cycles, the invention transfers multiple chips simultaneously onto a support substrate in one operation, then transfers the entire assembly in a second operation. This merging reduces the number of thermal and pressure cycles from millions to just two, significantly improving bonding reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The support substrate acts as an intermediary carrier between the chip source and the final circuit board. This intermediary enables batch processing by temporarily holding multiple chips in a stable configuration, allowing all chips to be attached to the support substrate under controlled conditions once, then transferred together to the final destination, minimizing repeated thermal and mechanical stress.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If excessive thermal transfer is applied, then transfer process completes, but number of bonding failures increases

Engineering Contradiction:
Improvetransfer process completionVSAvoidbonding failure rate
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The transfer process uses periodic, controlled thermal and pressure application rather than continuous excessive heating. Two distinct periodic cycles are employed: first for attaching chips to the support substrate, and second for transferring the assembly to the circuit board. Each cycle is controlled and limited in duration and intensity, preventing the excessive thermal accumulation that causes bonding failures while still achieving complete transfer.

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 solution enables high-efficiency bonding of MicroLEDs to substrate circuits, reducing production time and increasing yield by stabilizing the transfer process and minimizing substrate damage, while allowing for adaptable arrangements and surface compatibility.

Implementation Method 1

A continuous or discontinuous adhesive film for adhering the light-emitting diodes is provided between the support and the light-emitting diodes

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3806168B1Light-emitting component
Publication Date: 2023.11.22 XIAMEN SANAN OPTOELECTRONICS CO LTD
  • EP3806168B1 patent drawingFigure 1~2
  • EP3806168B1 patent drawingFigure 3~4
  • EP3806168B1 patent drawingFigure 5~6

AI summary

A light-emitting component, comprising: a plurality of micro light-emitting diodes (100), the micro light-emitting diodes comprising semiconductor layer sequences (110), and the semiconductor layer sequences (110) at least consisting of a first type of semiconductor layer, a second type of semiconductor layer, and an active light-emitting layer located between the first type of semiconductor layer and the second type of semiconductor layer; a first electrical contact layer (121) electrically connected to a first type of semiconductor; a second electrical contact layer (122) electrically connected to the second type of semiconductor layer; and a support (200) for providing supports for the micro light-emitting diodes (100). A mucosa (300) for adhering the micro light-emitting diodes (100) is provided between the support (200) and the light-emitting component (100); the micro light-emitting diodes (100) are regularly arranged on the mucosa (300), and the problem that the micro light-emitting diodes (100) are required to be transferred for many times at an application end is solved; the light-emitting component is only required to be bonded to a substrate to constitute a light-emitting device suitable for application, and manufacturing efficiency of the application end is improved.