Single-Crystal Silicon Wafer RTA for Denuded Zone and BMD Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor wafers made of single-crystal silicon require enhanced mechanical robustness and controlled bulk microdefect (BMD) formation without introducing oxygen-induced stacking faults (OSF) defects, while maintaining a radially homogeneous BMD density across the wafer.
Innovation Solution
A method involving the Czochralski growth of single-crystal silicon wafers with specific oxygen and nitrogen concentration control, followed by a series of Rapid Thermal Annealing (RTA) treatments in argon and ammonia atmospheres to create a denuded zone and promote BMD formation, ensuring mechanical robustness and homogeneous BMD distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If RTA treatment under argon with holding temperature over 1300°C is applied, then oxygen diffuses out near the surface creating a shallow DZ, but the mechanical robustness of the semiconductor wafer is weakened
Solution Approach 1:
The patent applies multiple RTA treatments with different temperature parameters (first treatment at higher temperature to create DZ, second treatment at lower temperature to preserve strength) to optimize both DZ depth and mechanical robustness simultaneously
Solution Approach 2:
The first RTA treatment is performed in advance to establish the desired oxygen distribution and DZ structure before the second RTA treatment, which then fine-tunes the properties without creating excessive oxygen loss
2Strength
If the semiconductor wafer is doped with nitrogen to strengthen mechanical robustness and promote BMD formation, then mechanical robustness is improved, but OSF defects are introduced
Solution Approach 1:
The patent removes nitrogen from the system by using intrinsic silicon material without nitrogen doping, thereby eliminating the source of OSF defects while maintaining mechanical robustness through controlled oxygen distribution achieved by RTA treatments
Solution Approach 2:
The patent converts the potential harm of oxygen (which can cause OSF defects when combined with nitrogen) into a beneficial element by precisely controlling oxygen distribution through RTA treatments to create the desired DZ structure without nitrogen-induced defects
3Stability of the object's composition
If multiple RTA treatments are applied to control oxygen distribution and create DZ, then DZ depth and BMD formation are improved, but the process complexity increases
Solution Approach 1:
The patent divides the oxygen distribution control process into two distinct RTA treatment steps, each with specific temperature and atmosphere parameters, allowing independent optimization of DZ creation and mechanical property preservation
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 produces semiconductor wafers with improved mechanical robustness and controlled BMD formation, maintaining a denuded zone and homogeneous BMD density across the wafer, reducing OSF defects and enhancing thermal stress resistance.
Implementation Method 1
growing a single crystal of silicon using the CZ method
Implementation Method 2
control the quotient of pulling speed V and axial temperature gradient G at the phase boundary between the single crystal and the melt
Implementation Method 3
Rapid Thermal Annealing (RTA) treatments in argon and ammonia atmospheres to create a denuded zone
Implementation Method 4
oxygen diffuses out near the surface under such conditions
Implementation Method 5
the semiconductor wafer can be doped with nitrogen, for example
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Method for producing a semiconductor wafer from single-crystal silicon, comprising in this order: growing a single crystal from silicon according to the CZ method; separating at least one semiconductor wafer from single-crystal silicon from the single crystal; a first, second and third RTA treatment of the semiconductor wafer.