Composite Substrate Intermediate Layer Porosity for Void Suppression
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Solution Overview
Problem
The occurrence of voids on the joining interface during annealing treatment in composite substrates, which can lead to deterioration of joining strength and peeling of functional substrates from support substrates, is a challenge in existing fabrication methods.
Innovation Solution
Forming spaces inside the intermediate layer at a predetermined area rate of 1% to 7% relative to the extending direction of the intermediate layer, which prevents the confinement and expansion of impurities like moisture and gas, thereby suppressing void formation during annealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If annealing treatment is performed to improve joining strength through covalent bond formation, then joining strength is improved, but voids occur on the joining interface due to expansion of trapped impurities
Solution Approach 1:
The patent applies surface activation treatment to the joining surfaces before joining, which removes organic contaminants and creates a more reactive surface. This preliminary action ensures that fewer impurities are trapped during joining, reducing the risk of void formation during subsequent annealing treatment while still achieving strong covalent bonds.
Solution Approach 2:
The patent performs the joining and annealing processes in a controlled atmosphere environment (inert or vacuum). This prevents additional moisture and gas from adhering to the joining surfaces during the process, minimizing impurity contamination that would otherwise expand during annealing and create voids on the joining interface.
2Strength
If surface activation treatment is applied to activate joining surfaces, then joining strength is improved, but impurities like moisture and gas may adhere to the surfaces and be trapped in the intermediate layer
Solution Approach 1:
The patent performs surface activation treatment and subsequent joining operations in a controlled atmosphere environment (inert gas or vacuum). This prevents moisture and gas from adhering to the activated surfaces, eliminating the harmful effect of impurity contamination while preserving the benefits of surface activation for achieving strong joining.
Solution Approach 2:
The patent performs surface activation treatment as a preliminary step immediately before joining, and maintains the surfaces in a protected environment throughout the process. This timing and environmental control ensure that surfaces are activated when needed but protected from re-contamination by moisture and gas that would otherwise be trapped in the intermediate layer.
3Ease of manufacture
If direct joining of substrates is performed, then manufacturing process is simplified, but joining strength is insufficient without additional annealing treatment
Solution Approach 1:
The patent applies surface activation treatment as a preliminary step before direct joining, which enhances the surface reactivity and bonding capability. This allows direct joining to achieve sufficient joining strength without requiring additional annealing treatment, thus simplifying the manufacturing process while maintaining strong joining.
Solution Approach 2:
The patent performs direct joining in a controlled atmosphere environment, which prevents impurity contamination and enables strong bonding through direct joining alone. This eliminates the need for subsequent annealing treatment to compensate for poor joining quality, simplifying the overall fabrication process while achieving adequate joining strength.
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 effectively suppresses voids on the joining interface, maintaining strong adhesion between functional and support substrates, ensuring robust composite substrate integrity.
Implementation Method 1
Spaces are formed inside the intermediate layer at a predetermined area rate relative to an extending direction of the intermediate layer. The predetermined area rate is 1% or more and 7% or less.
Data Source
AI summary
A composite substrate includes: a functional substrate having a predetermined function; a support substrate configured to support the functional substrate; and an intermediate layer provided between the support substrate and the functional substrate. The functional substrate and the support substrate are joined to each other with the intermediate layer in between. Spaces are formed inside the intermediate layer at a predetermined area rate relative to an extending direction of the intermediate layer. The predetermined area rate is 1% or more and 7% or less.