Low-Temperature Substrate Bonding with Pulsed Voltage
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Solution Overview
Problem
Existing substrate bonding methods face challenges in achieving high bond strength, processing time efficiency, and thermal stress due to high temperature annealing, especially when bonding substrates with different thermal expansion coefficients.
Innovation Solution
A method combining fusion prebonding and an electrically driven bond process, using a pulsed or AC voltage to form covalent bonds at lower temperatures, eliminating the need for high-temperature annealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high temperature annealing is applied to achieve sufficient bonding strength, then bond strength is improved, but thermal stress and risk of substrate damage increase
Solution Approach 1:
The invention changes the bonding parameters by applying electric voltage with pulsed or AC components at low temperatures (below 200°C), replacing the conventional high temperature annealing process. This parameter change enables achieving sufficient bonding strength without exposing substrates to high temperatures that cause thermal stress and potential damage, particularly for substrates with different thermal expansion coefficients
Solution Approach 2:
The invention substitutes the thermal field (high temperature annealing) with an electrical field (applied voltage with pulsed or AC components). This replacement of the physical field type enables bond formation through electrical driving forces rather than thermal activation, thereby avoiding thermal stress while achieving strong bonds
2Strength
If high temperature annealing is applied to increase covalent bonds, then bonding strength is improved, but processing time increases
Solution Approach 1:
The invention changes the bonding mechanism from thermally activated covalent bond formation to electrically driven bond formation. By applying voltage with pulsed or AC components, the process activates bond formation at low temperatures without requiring extended time periods, thus reducing processing time while maintaining or improving bonding strength
Solution Approach 2:
The invention employs periodic or pulsed voltage application to drive the bonding process. The pulsed or AC voltage components create periodic electrical fields that facilitate rapid bond formation at the substrate interface, significantly reducing the time required compared to continuous high temperature annealing
3Strength
If fusion bonding is applied to bond substrates with different thermal expansion coefficients, then substrate connection is achieved, but intrinsic stresses cause damaging or breaking of bonding interface
Solution Approach 1:
The invention changes the bonding temperature parameter from high temperature to low temperature (below 200°C), which minimizes thermal expansion differences between substrates with different thermal expansion coefficients. This parameter change prevents the formation of intrinsic stresses that would otherwise damage or break the bonding interface, thereby improving reliability while maintaining strong substrate connection
Solution Approach 2:
The invention substitutes thermal bonding with electrical bonding by applying voltage with pulsed or AC components. This replacement eliminates the thermal cycling that causes differential expansion and contraction in substrates with different thermal expansion coefficients, thereby preventing intrinsic stress formation and bonding interface damage while achieving reliable substrate connection
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 results in strong, homogeneous, and durable substrate connections with reduced thermal stress and processing time, enabling precise alignment and improved bond quality.
Implementation Method 1
the application of the voltage with the pulsed or AC component stipulates migration of material, such as atoms and/or ions, at the substrate interface
Implementation Method 2
creation of chemical and/or charge gradients may form at the interface region, which can give rise to covalent and/or ionic bonds between the substrates
Implementation Method 3
creation of chemical and/or charge gradients may form at the interface region, which can give rise to covalent and/or ionic bonds between the substrates
Implementation Method 4
The bonding is based on intermolecular interactions including van der Waals forces, hydrogen bridges (formed during the fusion prebonding step)
Implementation Method 5
The bonding is based on intermolecular interactions including van der Waals forces, hydrogen bridges (formed during the fusion prebonding step)
Data Source
Figure 1a~1h
AI summary
The present invention relates to a method for low temperature bonding of substrates (10, 12), comprising the steps of: providing a first substrate (10) and a second substrate (12); aligning the first substrate (10) and the second substrate (12); prebonding the first substrate (10) and the second substrate (12) by a fusion prebonding process; and bonding the first substrate (10) and the second substrate (12) by applying an electric voltage between the first substrate (10) and the second substrate (12), wherein said voltage comprises a pulsed or AC component.