Surfactant-Controlled Bonding for Thin Glass Sheet Debonding
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Solution Overview
Problem
There is a need for a thin glass sheet and substrate article that can withstand high temperature processing while allowing the glass sheet to be removed from the substrate without breaking, and for the substrate to be reusable in the manufacturing of portable electronic devices like TFTs and touch sensors, where the bonding strength between the glass sheet and the carrier must be strong enough for fabrication but weak enough for debonding without damage.
Innovation Solution
A method involving a surfactant, such as diethanolamide or polyethylene glycols, is used to control the adhesion between the glass sheet and the substrate, creating a temporary bond that is strong enough for high temperature processing but weak enough for debonding without breaking the sheet or substrate, by controlling van der Waals and covalent bonding energies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If glass etching processes are used to thin substrates, then the substrate becomes thinner and lighter, but the manufacturing process complexity increases and production time is extended
Solution Approach 1:
The substrate is pre-thinned to the desired thickness before TFT device fabrication begins, eliminating the need for post-fabrication thinning processes. This preliminary thinning allows direct fabrication on thin substrates without requiring additional etching steps, thereby improving productivity while achieving the desired substrate thickness and weight reduction
Solution Approach 2:
The thinning operation is extracted from the fabrication process sequence and performed as a preliminary standalone step, separating the thinning function from the device manufacturing steps. This allows the thin substrate to be prepared in advance and used directly in fabrication equipment without requiring integration of complex in-situ thinning processes
2Strength
If high temperature processing is applied to promote permanent bonding, then the bonding strength between layers increases, but the ability to separate layers after fabrication is lost
Solution Approach 1:
The bonding characteristics are controlled by adjusting processing parameters such as temperature, atmosphere composition, and exposure time. By optimizing these parameters, a bond strength is achieved that is sufficient for device fabrication but remains below the threshold for permanent irreversible bonding, allowing subsequent separation of layers after fabrication
Solution Approach 2:
The bonding system is designed to exhibit dynamic characteristics where the bond strength evolves during processing but remains controllable. The bonding interface maintains a state where thermal energy is sufficient to ensure stability during fabrication but insufficient to create permanent covalent bonds that would prevent separation, enabling adaptive bonding behavior
3Reliability
If the bonding strength between thin glass sheet and carrier is increased, then the lamination stability during processing improves, but the ability to separate them without breaking the sheet is lost
Solution Approach 1:
The bonding characteristics are optimized to provide uniform distribution of bond strength across the lamination interface. This ensures adequate stability during processing while maintaining consistent separation properties throughout the sheet area, allowing complete removal of the thin glass sheet from the carrier without localized failure or breaking
Solution Approach 2:
A controlled bonding mechanism acts as an intermediary between the thin glass sheet and carrier, providing sufficient adhesion for processing stability while inherently limiting maximum bond strength to prevent permanent bonding. This intermediary bonding layer or mechanism enables both lamination stability during fabrication and clean separation afterward
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 allows for the successful separation of the glass sheet from the substrate after high temperature processing without damage, enabling the reuse of the substrate and maintaining the surface integrity of both the sheet and substrate, thus reducing manufacturing costs and improving the flexibility of device production.
Implementation Method 1
control both room-temperature van der Waals, and/or hydrogen, bonding and high temperature covalent bonding between the thin sheet and carrier
Implementation Method 2
control both room-temperature van der Waals, and/or hydrogen, bonding and high temperature covalent bonding between the thin sheet and carrier
Implementation Method 3
a surfactant disposed between the substrate bonding surface and the sheet bonding surface
Data Source
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AI summary
Described herein are substrates, sheets, or both having a residual surfactant that may be applied thereto to control van der Waals, hydrogen and covalent bonding between the substrate and the sheet. The sheet and substrate are bonded together such that a permanent bond is prevented during high temperature processing but while maintaining a sufficient bond to prevent delamination during the high temperature processing. The substrate and sheet remain debondable through-out and subsequent to the high temperature processing.