Surface Modification Layers for Reusable Thin Glass Carrier Bonding
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Solution Overview
Problem
Current methods for processing flexible glass sheets on carriers face challenges such as contamination, loss of bond strength, and inability to reuse carriers due to strong covalent bonds, which are incompatible with high-temperature and harsh environments in Flat Panel Display (FPD) processing.
Innovation Solution
The use of surface modification layers on thin sheets and carriers to control van der Waals and covalent bonding, allowing for a temporary bond strong enough to withstand FPD processing while being weak enough for easy debonding after high-temperature processing, enabling carrier reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive wafer bonding is used to bond thin glass sheets to carriers, then the bond strength is sufficient to withstand FPD processing, but the strong covalent bonds prevent carrier reuse
Solution Approach 1:
The patent changes the bonding mechanism from strong covalent bonds to reversible van der Waals forces by controlling surface energy parameters. The carrier and thin glass sheet are bonded at room temperature where van der Waals forces dominate, but at high processing temperatures (above 200°C) these forces become reversible, allowing easy debonding. This parameter change enables both sufficient bond strength during processing and carrier reuse afterward.
Solution Approach 2:
The patent employs a composite bonding approach where the interface between carrier and thin glass sheet exhibits temperature-dependent bonding characteristics. At low temperatures, the interface behaves as a strong bond; at high temperatures, it transitions to a reversible interaction. This composite material strategy combines the benefits of strong bonding during processing with easy separation for carrier reuse.
2Strength
If commercial polymer adhesives are used for bonding, then the bond strength is sufficient, but the thick adhesive layers cause contamination through outgassing and solvent release
Solution Approach 1:
The patent extracts the adhesive layer entirely from the bonding interface, replacing it with direct surface-to-surface bonding between carrier and thin glass sheet. This eliminates the source of contamination (thick polymer layers containing solvents and volatiles) while maintaining sufficient bond strength through controlled van der Waals forces and hydrogen bonding at the interface.
Solution Approach 2:
The patent introduces surface energy control as an intermediary mechanism to enable bonding without physical adhesive materials. By controlling the surface energy of the carrier and thin glass sheet, the patent achieves strong bonding through molecular interactions at the interface, eliminating the need for thick polymer adhesive layers that cause contamination.
3Ease of manufacture
If van der Waals bonding is used initially, then the bond forms easily at room temperature, but the bond strength is insufficient for high-temperature FPD processing
Solution Approach 1:
The patent creates a dynamic bonding system where the bonding mechanism transitions with temperature. At room temperature, van der Waals forces provide strong bonding for easy manufacturing. During high-temperature FPD processing, the bonding becomes reversible through controlled debonding and rebonding cycles, maintaining integrity while allowing eventual carrier reuse. The bond strength is thus dynamically adapted to processing conditions.
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 approach allows for the successful processing of thin glass sheets through harsh FPD environments, including high temperatures, without contamination and enables the reuse of carriers, maintaining hermeticity and preventing delamination during processing.
Implementation Method 1
surface modification layers on thin sheets and carriers to control van der Waals and covalent bonding
Implementation Method 2
surface modification layers on thin sheets and carriers to control van der Waals and covalent bonding
Data Source
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Figure 2
Figure 3~5
AI summary
A method of controllably bonding a thin sheet having a thin sheet bonding surface with a carrier having a carrier bonding surface, by depositing a carbonaceous surface modification layer onto at least one of the thin sheet bonding surface and the carrier bonding surface, incorporating polar groups with the surface modification layer, and then bonding the thin sheet bonding surface to the carrier bonding surface via the surface modification layer. The surface modification layer may include a bulk carbonaceous layer having a first polar group concentration and a surface layer having a second polar group concentration, wherein the second polar group concentration is higher than the first polar group concentration. The surface modification layer deposition and the treatment thereof may be performed by plasma polymerization techniques.