Thin-Layer Transfer on Cavitated Substrates With a Cavity-Free Fracture Zone
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Solution Overview
Problem
Existing methods for transferring thin layers onto substrates with cavities are inefficient and costly, particularly due to defects such as microcracks and blisters that occur during Smart Cut™ technology, which can lead to incomplete or failed transfers, especially when the receiver substrate is fully covered with cavities.
Innovation Solution
A method and substrate design that includes a bonding face with a region devoid of cavities and an intercavity space, occupying 15-50% of the bonding face, to initiate fracture and control defect growth, ensuring complete transfer of the thin layer onto a receiver substrate with cavities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If Smart Cut technology is used to transfer thin layers onto substrates with cavities, then the transfer process can be completed, but defects such as microcracks and blisters occur during the process leading to incomplete or failed transfers
Solution Approach 1:
The patent applies local quality by creating a region devoid of cavities at a specific location on the receiver substrate. This local modification allows the fracture to be properly initiated and controlled in that specific area, while the rest of the substrate maintains its cavity structure. The region devoid of cavities serves as a controlled zone where the fracture propagation can be managed, preventing random blister formation and ensuring complete layer transfer.
2Adaptability or versatility
If the receiver substrate is fully covered with cavities, then the cavity sealing application is optimized, but the bonding surface area is reduced leading to failed fracture initiation
Solution Approach 1:
The patent creates a localized region devoid of cavities with specific surface area requirements (at least 1 mm²) to ensure proper fracture initiation. This local modification allows the substrate to maintain high overall cavity coverage for application optimization while providing a sufficient bonding surface area in the cavity-free region for reliable fracture initiation and propagation.
3Ease of manufacture
If ion implantation is performed to form a weakening plane, then the thin layer transfer can be enabled, but defects are pressurized and develop into microcracks or blisters during heat treatment
Solution Approach 1:
The patent extracts or removes cavities from a specific region to create a zone devoid of cavities. This extraction eliminates the harmful effect of cavity-induced blister formation in that local area, allowing the fracture to propagate controllably through the weakened plane without being disrupted by cavity-related defects during the heat treatment process.
Solution Approach 2:
The patent converts the potential harm of defect propagation into a benefit by providing a controlled environment (region devoid of cavities) where the fracture can propagate in a predictable and controlled manner. The region devoid of cavities acts as a designated zone that guides the fracture propagation, transforming the uncontrolled defect growth into a controlled and reliable transfer process.
4Area of stationary object
If a large bonding surface is used, then the fracture initiation is facilitated, but the cavity coverage is reduced affecting the application performance
Solution Approach 1:
The patent applies local quality by concentrating the bonding surface requirement in a specific localized region (devoid of cavities) rather than distributing it across the entire substrate. This allows the bonding surface area to be sufficient for fracture initiation (at least 1 mm²) while the rest of the substrate can be optimized with high cavity coverage for application-specific performance.
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
The method effectively seals cavities by controlling defect propagation, enhancing the reliability and completeness of thin layer transfer, even on substrates with large bonding surfaces and multiple cavities.
Implementation Method 1
ion species such as hydrogen and/or helium are implanted in a donor substrate in order to form therein a weakening plane
Implementation Method 2
This development involves an addition of energy, generally implemented by means of a heat treatment of a few hundreds of degrees, typically 500° C., for a few tens of minutes
Implementation Method 3
This leads to the formation of a confined layer of microcracks within which a fracture will initiate and propagate. This fracture separates the donor substrate along the weakening plane and a thin layer of the donor substrate is thus transferred to the support substrate
Data Source
AI summary
A method for transferring a semiconductor layer from a donor substrate having a weakening plane to a receiver substrate having comprising a bonding face that has open cavities includes putting the donor substrate and the bonding face of the receiver substrate in contact, producing an assembly wherein the cavities are buried, and separating the assembly by fracture along the weakening plane. The bonding face of the receiver substrate includes, apart from the open cavities, a bonding surface that comes into contact with the donor substrate when the assembly is produced. The bonding surface includes a region devoid of cavities one dimension of which is at least 100 μm and which has a surface area of at least 1 mm2, and an intercavity space that occupies from 15 to 50% of the bonding face of the receiver substrate.