Reversible Bonding via Oxide Layer Degradation
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Solution Overview
Problem
Existing methods for reversible bonding between thin and ultrathin substrates used in microelectronic device production face challenges such as fragility, damage from mechanical separation, incompatibility with high-temperature processes, and degradation from chemical or microwave separation methods, particularly when exposed to thermal budgets above 400°C.
Innovation Solution
A reversible bonding process involving the production of an oxide layer between substrates, which forms a bonding interface that can be physically or chemically degraded using a controlled humid atmosphere or laser radiation for separation, avoiding mechanical damage and the use of adhesive polymers, and allowing for high-temperature compatibility without prior surface preparation or protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If direct bonding is used between thin substrate and thick substrate, then bonding strength is improved, but separation becomes difficult and causes substrate damage
Solution Approach 1:
An intermediate layer is introduced between the thin substrate and thick substrate to enable reversible bonding. This intermediate layer allows strong bonding during processing while enabling clean separation afterward without damaging the substrates, thus resolving the contradiction between bonding strength and separation ease.
2Ease of operation
If adhesive polymers are used as intermediate layer, then separation ease is improved, but compatibility with high-temperature processes deteriorates
Solution Approach 1:
The intermediate layer material is selected or designed to change its properties at specific temperatures. The layer remains stable and provides strong bonding at processing temperatures (resisting degradation up to 400°C or higher), but undergoes controlled degradation or phase change at separation temperatures, enabling easy substrate separation while maintaining thermal compatibility.
3Ease of operation
If mechanical separation is used, then separation ease is improved, but substrate damage increases
Solution Approach 1:
The separation process replaces mechanical force with chemical or thermal mechanisms. The intermediate layer is designed to degrade chemically or undergo phase change under controlled conditions, allowing substrates to separate naturally without mechanical contact that could cause damage to thin or fragile substrates.
4Ease of operation
If chemical separation methods are used, then separation ease is improved, but component degradation increases
Solution Approach 1:
The intermediate layer is designed with selective chemical properties that enable degradation under specific controlled conditions. The chemical degradation is localized to the intermediate layer while the substrates and their components remain protected. This selective degradation enables easy separation without harmful effects on the microelectronic components fabricated on the substrates.
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 method enables secure bonding and easy separation of substrates without damaging the microelectronic components, maintaining substrate integrity and allowing for reuse, while being compatible with high-temperature processes, thus addressing the limitations of existing techniques.
Implementation Method 1
production of at least one oxide layer on at least one first face of the first element and/or on at least one first face of the second element
Implementation Method 2
the oxide layer forms a bonding interface between the first element and the second element
Implementation Method 3
separation of the second element vis-à-vis the first element by the application of a heat treatment in a controlled humid atmosphere physically and/or chemically degrading the oxide layer
Data Source
Figure 1~3
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Figure 7~8
AI summary
A reversible bonding method between a first element (102) and a second element (112), comprising the implementation of the following steps: a) production of at least one oxide layer (110) on at least one first face (104) of the first element (102) and/or on at least one first face (114) of the second element (112); b) bonding of the first face (104) of the first element (102) with the first face (114) of the second element (112) such that the oxide layer (110) forms a bonding interface between the first element (102) and the second element (112); c) decoupling of the second element (112) from the first element (102) by the application of a heat treatment under a controlled humid atmosphere physically and/or chemically degrading the oxide layer (110).