Stiffener-Assisted Fracturing of Composite Substrates
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Solution Overview
Problem
Existing methods for fracturing composite structures along an embrittlement plane, such as those used in SMART CUT technology, often result in high breakage rates of the remaining donor substrate (negative) due to the release of strong energy during the fracturing process, particularly when dealing with hard or brittle materials like GaN and silicon.
Innovation Solution
The method involves placing stiffeners on both sides of the composite structure, spaced closely but not touching, to absorb and redistribute the energy released during fracturing, thereby reducing the risk of breakage by maintaining a 'held' contact and minimizing local compression points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fracturing is performed by thermal annealing or mechanical energy supply, then the thin layer is transferred onto the support substrate, but the remaining donor substrate (negative) breaks at a rate of 80%
Solution Approach 1:
The patent applies beforehand cushioning by bonding a stiffener to the donor substrate before the fracturing process. This stiffener acts as a cushioning element that absorbs and distributes the energy released during fracturing, preventing the negative from breaking while still allowing the thin layer to be transferred successfully.
Solution Approach 2:
The patent uses composite materials by creating a composite structure consisting of the donor substrate bonded to a stiffener. This composite structure combines the properties of the original substrate with the reinforcing properties of the stiffener, enabling the structure to withstand fracturing energy without breaking the negative.
2Manufacturing precision
If the donor substrate is made hard and brittle (such as GaN, SiC) to achieve low defect density, then the substrate quality is improved, but the substrate becomes more susceptible to breakage during fracturing
Solution Approach 1:
The patent creates a composite structure by bonding a stiffener to the hard and brittle donor substrate. This composite approach maintains the low defect density property of the original substrate while adding the strength and toughness of the stiffener material, thereby resolving the contradiction between quality and breakage resistance.
Solution Approach 2:
By bonding the stiffener beforehand, the patent prepares the substrate to withstand the stresses of fracturing. The stiffener serves as a pre-positioned cushioning element that protects the brittle substrate from breaking during the energy release phase of fracturing, while the substrate itself maintains its low defect density.
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 the number of negative breakages during fracturing, with tests showing an 80% reduction in breakage rates, allowing for the reuse of the donor substrate and improving the reliability of thin layer transfer.
Implementation Method 1
placing stiffeners on both sides of the composite structure, spaced closely but not touching, to absorb and redistribute the energy released during fracturing
Implementation Method 2
SMART CUT® technology consists of implanting ionic species under a face of the donor substrate to form an embrittlement plane
Implementation Method 3
Fracturing the structure may be done by thermal annealing at a given temperature and/or by supplying mechanical energy
Data Source
AI summary
A method of fracturing a composite structure along an embrittlement plane defined between two layers by producing a fracture in the structure along the embrittlement plane. During fracturing, the composite structure is disposed in a boat housing and held in contact against stiffeners disposed on both sides of the structure and aligned parallel to each other. Each stiffener has a diameter that is at least 40% to 300% of the diameter of the composite structure to be fractured.