Basic Molecule-Assisted Direct Bonding for Low-Temperature Multilayers
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Solution Overview
Problem
Direct bonding methods face challenges in achieving high bonding energy at low temperatures, particularly for substrates requiring low thermal budgets, and may be incompatible with certain materials or increase costs due to plasma treatment, which can also affect device performance.
Innovation Solution
A method involving direct bonding between substrates in a basic environment followed by a thermal treatment between 20° C. and 1000° C., preferably 100° C. to 500° C., to enhance bonding energy without affecting adhesion energy, suitable for various materials and applications, including those with electronic and opto-electronic components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If plasma treatment is used to increase bonding energy, then bonding energy increases rapidly, but the method becomes incompatible with certain substrates and increases cost and time
Solution Approach 1:
The patent introduces a molecular layer as an intermediary between the substrate surfaces during bonding. This molecular mediator enables high bonding energy without requiring plasma treatment, thereby maintaining substrate compatibility and avoiding the harmful effects of plasma on certain materials while still achieving the desired bonding strength.
Solution Approach 2:
The patent replaces the plasma treatment process (which modifies surfaces through energetic particle bombardment) with a molecular layer formation process. This substitution eliminates the need for plasma while achieving comparable or superior bonding energy, particularly for substrates that are sensitive to plasma treatment.
2Strength
If plasma treatment is applied to increase bonding energy, then bonding energy reaches around 5 J/m2, but the treatment modifies the surface over a thickness of 1-10 nm which may affect future devices
Solution Approach 1:
The molecular layer serves as an intermediary that provides the necessary bonding energy without directly modifying the substrate surface. Unlike plasma treatment that etches or oxidizes the surface, the molecular layer approach maintains surface integrity while achieving high bonding energy, thus avoiding interfacial charge problems and uncontrolled oxide layer formation.
Solution Approach 2:
The patent uses a thin molecular layer that can be formed and then serves its purpose during bonding. This disposable molecular intermediary provides the necessary bonding enhancement without creating permanent surface modifications that would affect subsequent device processing.
3Ease of manufacture
If conventional direct bonding is carried out at ambient temperature and pressure, then the process is simple, but bonding energy remains limited and may not suffice for substrates requiring low thermal budgets
Solution Approach 1:
The patent applies preliminary action by forming a molecular layer on the substrate surfaces before the bonding process. This pre-treatment enhances the bonding energy available during subsequent bonding operations, enabling low-temperature bonding that would otherwise be insufficient for substrates with low thermal budgets.
Solution Approach 2:
The patent changes the chemical parameters of the bonding interface by introducing a molecular layer with specific chemical properties. This parameter change enables bonding at lower temperatures while maintaining or enhancing bonding energy, making the process suitable for substrates that cannot withstand high temperatures.
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 achieves high bonding energy at low temperatures, ensuring mechanical strength and compatibility with subsequent processes like Smart Cut, without affecting adhesion energy or damaging substrates, making it suitable for diverse materials and applications.
Implementation Method 1
disposing at least the direct binding interface in a basic environment
Implementation Method 2
applying a thermal treatment at a temperature of between 20° C. and 1000° C., in particular between 100° C. and 500° C.
Implementation Method 3
The direct bonding is a spontaneous bonding between two surfaces without adding material to the interface between the bonded surfaces
Data Source
AI summary
A method for manufacturing a multilayer structure by direct bonding between a first substrate and a second substrate includes the steps of: a) providing a first substrate and a second substrate respectively including a first bonding surface and a second bonding surface, b) bringing the first bonding surface and the second bonding surface into contact so as to create a direct bonding interface between the first substrate and the second substrate, c) disposing at least the direct bonding interface in a basic environment, and d) applying a thermal treatment at a temperature of between 20° C. and 350° C. so as to obtain the multilayer structure.