Plasma Nitride SOI Structure for Uniform, Impurity-Resistant Bonding
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Solution Overview
Problem
Current methods for preparing semiconductor-on-insulator (SOI) structures are inefficient due to high costs, material wastage, and lack of thickness uniformity, especially for layers thinner than a few microns, and are sensitive to impurities and defects at the bond interface.
Innovation Solution
A method involving the deposition of a handle semiconductor nitride layer on a handle dielectric layer and bonding a donor dielectric layer to form a multilayer structure with insulating layers such as oxide-nitride-oxide (ONO) to resist impurities and improve layer transfer, using techniques like plasma deposition and annealing to enhance bond strength and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional wafer bonding methods are used to prepare SOI structures, then bonding can be achieved, but the process is sensitive to impurities and defects at the bond interface, resulting in poor reliability
Solution Approach 1:
A plasma nitride layer is deposited as an intermediary barrier between the handle substrate and the device layer. This nitride layer prevents impurities and defects from the handle substrate from affecting the device layer, while still allowing for successful wafer bonding through plasma activation of the bonding surfaces.
Solution Approach 2:
The bonding interface is segmented into multiple functional layers: the handle substrate, the plasma nitride barrier layer, and the device layer. This segmentation isolates the device layer from impurities in the handle substrate while maintaining the structural integrity of the bonded interface.
2Productivity
If conventional layer transfer methods are used, then layer transfer can be achieved, but the process is time-consuming and costly with material wastage
Solution Approach 1:
Plasma nitride deposition and plasma activation are performed as preliminary actions before bonding. These preliminary treatments prepare the surfaces for efficient bonding and layer transfer, eliminating the need for time-consuming post-bonding processing steps and reducing overall manufacturing time.
Solution Approach 2:
The process utilizes plasma parameters (power, pressure, gas composition) to control the deposition and activation processes, enabling precise control over layer properties and bonding quality, which improves efficiency and reduces rework.
3Manufacturing precision
If thick film device layers are used, then the device layer can be sufficiently thick for certain applications, but thickness uniformity is difficult to achieve for layers thinner than a few microns
Solution Approach 1:
The mechanical grinding process is replaced with plasma-based deposition and activation processes. Plasma deposition provides atomic-layer precision and excellent thickness uniformity, while plasma activation enables clean separation without mechanical contact, achieving uniform thickness even for sub-micron layers.
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 reduces costs, improves thickness uniformity, and enhances the resistance of the SOI structure to impurities, resulting in a more efficient and reliable semiconductor-on-insulator layer transfer process.
Implementation Method 1
a plasma nitride layer and method of manufacture thereof
Implementation Method 2
followed by a thermal treatment to strengthen the bond. The anneal may convert the terminal silanol groups to siloxane bonds between the two interfaces, thereby strengthening the bond.
Implementation Method 3
Particles (atoms or ionized atoms, e.g., hydrogen atoms or a combination of hydrogen and helium atoms) are implanted at a specified depth beneath the front surface of the donor wafer. The implanted particles form a cleave plane in the donor wafer at the specified depth at which they were implanted.
Implementation Method 4
The surfaces of the wafers can be additionally chemically activated by a wet treatment, such as an SC1 clean or hydrofluoric acid. The wet treatment and the plasma activation may occur in either order, or the wafers may be subjected to only one treatment.
Data Source
AI summary
A method is provided for preparing a semiconductor-on-insulator structure comprising a silicon nitride layer deposited by plasma deposition.