Silicon Crystal Defect Characterization via Localized Light Scanning
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Solution Overview
Problem
Conventional methods for characterizing defects in silicon crystals are lengthy, resource-intensive, and lack accuracy, making them inefficient and environmentally unfriendly, while also requiring different processes for various defects.
Innovation Solution
A method involving etching a silicon wafer to remove a predicted thickness, followed by localized light scattering (LLS) scanning to obtain a LLS map, latex sphere equivalent (LSE) size of defects, and defect bulk density, allowing for the determination of defect type and zone based on these parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional characterization processes are used, then defect characterization can be performed, but the characterization period is long and productivity is low
Solution Approach 1:
The patent replaces mechanical/chemical etching methods with optical detection (localized light scattering technique) to characterize defects. The LLS technique uses light scattering patterns to identify and classify defects without requiring extensive sample preparation or lengthy measurement processes, thus improving both accuracy and productivity simultaneously
Solution Approach 2:
The patent changes the measurement parameters by using light scattering intensity and angular distribution as primary characterization parameters instead of relying on traditional methods that require visual inspection or complex imaging. This parameter transformation enables automated, rapid, and accurate defect detection
2Measurement precision
If conventional characterization processes are used, then defect characterization can be performed, but resource consumption and labor costs are high
Solution Approach 1:
The LLS system performs automated defect characterization without requiring expert operator intervention. The system automatically acquires light scattering data, processes the signals, identifies defect types, and generates characterization results, thereby eliminating the need for highly skilled technicians and reducing labor costs while maintaining high accuracy
Solution Approach 2:
The patent extracts only the essential light scattering signal information needed for defect characterization, discarding unnecessary measurement steps and complex sample preparation procedures. This selective extraction of critical information reduces resource consumption while preserving characterization accuracy
3Measurement precision
If conventional characterization processes are used, then defect characterization can be performed, but environmental friendliness is poor
Solution Approach 1:
The patent replaces chemical etching and staining processes with non-destructive optical measurement. The LLS technique characterizes defects using light scattering without requiring harsh chemicals or generating harmful waste, thereby improving environmental friendliness while maintaining characterization accuracy
4Measurement precision
If conventional characterization processes are used, then defect characterization can be performed, but the process complexity is high
Solution Approach 1:
The LLS system serves multiple functions: it detects various defect types (dislocations, stacking faults, inclusions), characterizes their spatial distribution, and provides quantitative analysis all through a single measurement process. This multi-functionality simplifies the overall characterization process while maintaining comprehensive and accurate defect analysis
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 method reduces characterization time and cost, enhances accuracy, and can simultaneously identify multiple defect types like vacancies, oxygen precipitates, and dislocations with high reliability, while being environmentally friendly and applicable to all crystal defects.
Implementation Method 1
conducting a localized light scattering (LLS) scanning to a surface of the etched silicon crystal to obtain a LLS map of the surface
Implementation Method 2
etching the surface of the silicon crystal under atmosphere of a hydride of Group VII, at temperature of 700° C. or higher
Data Source
AI summary
The present application provides a method for characterizing defects in silicon crystal comprising the following steps: etching a surface of the silicon crystal to remove a predicted thickness of the silicon crystal; conducting a LLS scanning to a surface of the etched silicon crystal to obtain a LLS map of the surface, a LSE size of defects, and defect bulk density; based on at least one of the LLS map of the surface, the LSE size of defects and the defect bulk density, determining a type of defect existing in the silicon crystal and/or a defect zone of each type of defect on the surface. By applying the method, the characterizing period and the characterizing cost can be reduced, plural defects such as vacancy, oxygen precipitate and dislocation can be characterized simultaneously, the characterizing accuracy can be enhanced, and the defect type and the defect zone can be determined with high reliability. In addition, the method can be applied to all crystal defect types, is easy to operate, and is an environmentally friendly method for determination of grown-in defects.