SOI Structure with Plasma Oxide Layer and Bonding Method
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Solution Overview
Problem
Current methods for preparing semiconductor-on-insulator (SOI) structures face challenges such as impurity influence from handle substrates, costly processes, and non-uniformity in layer thickness, especially in multilayer structures, which affect the quality and integration of semiconductor devices.
Innovation Solution
A method involving the deposition of a handle semiconductor nitride layer, followed by a nitride and oxide layer stack on a handle substrate, and bonding a donor dielectric layer to form a multilayer structure with a cleave plane, using insulating layers like silicon nitride, oxynitride, and oxide to create a robust and impurity-resistant SOI structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional thermal annealing is used to strengthen the bond between wafers, then the bond strength is improved, but impurities from the handle substrate can influence the device layer
Solution Approach 1:
An intermediate insulating layer is introduced between the handle substrate and the device layer to act as a barrier against impurity diffusion while still allowing the bond to be strengthened through thermal annealing. This intermediate layer mediates between the need for strong bonding and the need to protect against impurities.
Solution Approach 2:
The insulating layer is divided into multiple segments or layers with different compositions and properties. This segmentation allows each layer to perform specific functions: one layer provides strong adhesion to the handle substrate, another provides impurity barrier properties, and another provides good interface with the device layer.
2Object-affected harmful factors
If multilayer insulating structures are used to block impurities, then impurity resistance is improved, but the process complexity and cost increase
Solution Approach 1:
The patent uses composite insulating structures made from combinations of different materials (such as oxide-nitride-oxide stacks) where each material contributes specific properties. The composite structure provides superior impurity blocking compared to single materials while maintaining reasonable process complexity through established deposition techniques.
Solution Approach 2:
The patent optimizes parameters such as layer thickness, deposition temperature, and plasma power to achieve the desired impurity barrier properties. By carefully controlling these parameters, the multilayer structure provides effective protection without requiring excessive numbers of layers or complex processing steps.
3Ease of manufacture
If conventional bonding methods are used, then the bonding process is simple, but thickness uniformity of the device layer deteriorates
Solution Approach 1:
The insulating layers are deposited on the handle substrate before bonding to the device layer. This preliminary action ensures that the bonding interface is well-defined and uniform, which helps maintain thickness uniformity of the final device layer while still using relatively simple bonding processes.
Solution Approach 2:
The insulating layers provide locally optimized properties at the bonding interface, with different compositions and thicknesses tailored to specific regions. This local quality control ensures uniform thickness and properties across the entire device layer while maintaining ease of manufacture through standard deposition and bonding techniques.
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 enhances the resistance of the SOI structure to impurities from the handle substrate, reduces costs by eliminating the need for expensive processes, and achieves better thickness uniformity and integration quality, improving the overall performance of semiconductor devices.
Implementation Method 1
Prior to bonding, the donor wafer and/or handle wafer are activated by exposing the surfaces of the wafers to plasma containing, for example, oxygen or nitrogen. Exposure to the plasma modifies the structure of the surfaces in a process often referred to as surface activation, which activation process renders the surfaces of one or both of the donor water and handle wafer hydrophilic.
Implementation Method 2
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 voids are filled with hydrogen and helium. The voids become platelets. The pressurized gases in the platelets propagate micro-cavities and micro-cracks, which weaken the silicon on the implant plane.
Data Source
AI summary
A method is provided for preparing a semiconductor-on-insulator structure comprising a silicon oxynitride layer having a gradient oxygen concentration.