Micro-LED Transfer via Partial Scribe Line Cutting
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Solution Overview
Problem
In the production of LED display devices, the transfer of micro-LED chips is hindered by adhesive materials spilling and covering the chips due to their thickness and fluidity, resulting in a low transfer success rate during the multiple transfer processes.
Innovation Solution
A transfer method involving partial cutting of preset scribe lines on the epitaxial layer to create uncut areas, using temporary substrates with release adhesives and blue tape with a roller to separate the wafers, preventing adhesive spillage and maintaining the relative position of the wafers, thereby increasing the transfer success rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesive materials are used to transfer LED chips, then the transfer process can be completed, but the adhesive materials spill and cover the LED chips due to their thickness and fluidity, resulting in low transfer success rate
Solution Approach 1:
The scribe lines are partially cut before the transfer process to create uncut areas that will block adhesive spillage. This preliminary action prevents the harmful effect of adhesive covering the LED chips during the subsequent transfer operation.
Solution Approach 2:
The scribe lines are divided into cut portions and uncut portions, creating a segmented structure where the uncut areas serve as adhesive barriers while the cut areas allow for proper chip separation and transfer.
2Manufacturing precision
If multiple transfer processes are used to transfer LED chips from growth substrates to display backplanes, then the chips can be positioned correctly, but the process becomes complex and time-consuming with multiple adhesive applications
Solution Approach 1:
The partial cutting of scribe lines is performed in advance to create a structure that facilitates easier and more accurate chip transfer, reducing the complexity of the transfer process while maintaining positioning precision.
Solution Approach 2:
The uncut scribe line areas act as intermediaries that guide adhesive placement and prevent spillage, serving as a mediator between the adhesive material and the LED chips to enable accurate transfer with simpler processes.
3Ease of manufacture
If adhesive materials with certain thickness and fluidity are used for transfer, then the transfer can be performed, but the adhesive covers the thin LED chips (only a few microns thick), reducing transfer quality
Solution Approach 1:
Partial cutting of scribe lines is performed before transfer to create physical barriers that prevent adhesive from spreading onto the LED chip surfaces, thereby maintaining chip transfer quality while allowing the use of fluid adhesive materials.
Solution Approach 2:
The scribe lines have different properties in different areas: cut areas allow for chip separation while uncut areas provide adhesive blocking. This local differentiation of properties enables both easy manufacture and high precision transfer.
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 method effectively prevents adhesive coverage and maintains the position of the wafers, significantly increasing the LED chip transfer success rate and reducing production costs and inefficiencies.
Implementation Method 1
providing a roller that is arranged at the bottom of the blue tape and opposite to the to-be-transferred wafers, and jacking up the blue tape with the roller so that remaining scribe lines on the to-be-transferred wafers are automatically separated by breaking under action of stress
Implementation Method 2
providing a temporary substrate having a first release adhesive, adhering the first release adhesive to first side faces of the to-be-transferred wafers so as to adhere the to-be-transferred wafers to a temporary substrate
Implementation Method 3
providing a blue tape having a second release adhesive, adhering second release adhesive to second side faces of the to-be-transferred wafers so as to adhere the to-be-transferred wafers to the blue tape
Data Source
AI summary
Provided are a transfer method, a display device, and a storage medium. The transfer method includes: performing partial cutting on preset scribe lines (22) on an epitaxial layer to obtain to-be-transferred wafers (24) after cutting (S1); adhering a temporary substrate (26) on the to-be-transferred wafers (24) through adhering a first release adhesive (25) to first side faces of the to-be-transferred wafers (24), and removing a growth substrate (21) (S2); adhering the to-be-transferred wafers (24) to the blue tape (28) through adhering a second release adhesive (27) to second side faces of the to-be-transferred wafers (24), and removing the temporary substrate (26) (S3); jacking up the blue tape (28) with a roller so that remaining scribe lines (23) on the to-be-transferred wafers (24) are separated by breaking under action of stress (S4).