Double SOI Layer Transfer for Thick Wafers With Low Deformation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods like the Smart Cut™ process struggle to achieve large thicknesses for both semiconductor and oxide layers in double SOI structures, and the bonding process is susceptible to deformation and defects, especially in larger wafers, limiting their suitability for applications like photonics.
Innovation Solution
A method involving sequential oxidation and layer transfer steps, including forming oxide layers on both faces of the support substrate and donor substrates, followed by atomic species implantation and controlled detachment, to create a double semiconductor-on-insulator structure with balanced thermal expansion and reduced deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If surface treatments such as heat treatments are applied to reduce surface roughness, then bonding quality improves, but wafer deformation increases
Solution Approach 1:
The patent performs surface treatments at different stages of the multi-step process rather than attempting to treat the entire thick structure at once. By treating surfaces at intermediate stages when the structure is thinner, the thermal stress and deformation are reduced while still achieving the necessary surface quality for bonding.
2Productivity
If large diameter wafers (300 mm) are used for industrial production, then productivity increases, but susceptibility to deformation during bonding increases
Solution Approach 1:
The patent segments the bonding process into multiple smaller bonding operations on 300mm wafers rather than attempting a single complex multi-layer bond. Each bonding step involves thinner layers and lower stresses, making the large diameter wafers manageable while maintaining high production capacity.
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 enables the production of double SOI structures with sufficient thicknesses for photonic applications, minimizing deformation and ensuring high-quality bonding, thus overcoming the limitations of conventional processes.
Implementation Method 1
the oxide layer, formed on the rear face of the support substrate, contributing to the preservation of the flatness of the support substrate during the first and second transfer stages
Implementation Method 2
The Smart Cut process involves implanting atomic species, such as hydrogen (H) and/or helium (He), to create a weakened zone within a donor substrate
Implementation Method 3
the donor substrate is detached at the weakened zone to transfer a thin layer of the donor substrate onto the recipient substrate
Implementation Method 4
The bonding occurs between the surface of the recipient substrate and the surface of the oxide layer of the donor substrate
Data Source
Figure 1~3
Figure 4~6
Figure 7~8
AI summary
The invention relates to a process for fabricating a double semiconductor-on-insulator structure comprising from a back side to a front side of the structure: a handle substrate, a first electrically insulating layer (1b), a first single-crystal semiconductor layer (2), a second electrically insulating layer (2b) and a second single-crystal semiconductor layer (3), the process being characterized in that it comprises: - a first step of formation of an oxide layer on the front and back sides of the handle substrate, to form the first electrically insulating layer (1b) and an oxide layer (1a') on the back side of the handle substrate, - a first step of layer transfer, to transfer the first single-crystal semiconductor layer (2), - a second step of formation of an oxide layer, to form the second electrically insulating layer (2b), - a second step of layer transfer, to transfer the second single-crystal semiconductor layer (3).