Substrate Assembly via Anhydrous Dew Point Control
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Solution Overview
Problem
Molecular adhesion techniques for substrate assembly often result in bonding defects due to water diffusion and contamination, leading to inadequate adhesion and functional issues in microelectronics and optoelectronics applications.
Innovation Solution
An anhydrous treatment method is employed, where substrates are treated in an atmosphere with a dew point below −10° C. to prevent water diffusion and control the working atmosphere's dew point throughout the assembly process, ensuring a satisfactory degree of adhesion by maintaining the dew point below this threshold until the reinforcement annealing step.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If molecular adhesion assembly is performed with water present at the interface, then adhesion forces are created between substrates, but bonding defects appear due to water diffusion and gas species accumulation
Solution Approach 1:
The patent applies an inert atmosphere by controlling the dew point of the working atmosphere to below −10° C. during assembly and annealing processes. This creates a water-free environment that prevents water diffusion into the bonding interface, thereby eliminating bonding defects while maintaining reliable adhesion through molecular bonding mechanisms.
Solution Approach 2:
The patent changes the physical parameter of atmospheric humidity by controlling the dew point to below −10° C. This parameter change transforms the working atmosphere from a water-containing environment to a water-free environment, preventing water-related bonding defects while preserving the necessary conditions for molecular adhesion.
2Ease of manufacture
If substrates are assembled in a humid environment, then assembly process is simpler, but adhesion reinforcement is insufficient and bonding defects persist
Solution Approach 1:
The patent changes the atmospheric parameter by controlling dew point below −10° C. during assembly and annealing. This creates optimal conditions for molecular adhesion and adhesion reinforcement, ensuring complete water removal and strong bonding without compromising process simplicity, as the controlled atmosphere can be maintained throughout the entire process sequence.
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 significantly reduces or eliminates bonding defects, ensuring a robust and reliable adhesion between substrates, even in sensitive applications like silicon-on-insulator substrates and 3D structures, by maintaining a controlled, dry environment during assembly and annealing.
Implementation Method 1
reinforcing the degree of adhesion of the assembly beyond a threshold adhesion value at which water is no longer able to diffuse along the assembly interface
Implementation Method 2
control of the dew point of a working atmosphere to which the first and second substrates are exposed from the anhydrous treatment step and until the end of the second step
Implementation Method 3
The assembly obtained is then generally subjected to heat treatment at a temperature that may vary between 50° C. and 1200° C., depending on the nature of the substrates and the application envisaged, so as to reinforce the adhesion
Data Source
AI summary
A method for assembling two substrates by molecular adhesion comprises: a first step (a) of putting first and second substrates in close contact in order to form an assembly having an assembly interface; a second step (b) of reinforcing the degree of adhesion of the assembly beyond a threshold adhesion value at which water is no longer able to diffuse along the assembly interface. The method also comprises a step (c) of anhydrous treatment of the first and second substrates in a treatment atmosphere having a dew point below −10° C., and control of the dew point of a working atmosphere to which the first and second substrates are exposed from the anhydrous treatment step (c) until the end of the second step (b) so as to limit or prevent the appearance of bonding defects at the assembly interface.