Silicon Wafer Slip Dislocation Inspection via Angle-Tuned Optics
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Solution Overview
Problem
Conventional methods for detecting slip dislocations on silicon wafers suffer from insufficient detection sensitivity due to strong laser light scattering in the peripheral regions.
Innovation Solution
A silicon wafer defect inspection method and system that utilize specific angles between the light axis and detection optical axis to enhance detection sensitivity, with θ1 ranging from 67° to 78° and θ2 ranging from −6° to −1° or 1° to 6°, using a light source and photodetector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If laser light is used for defect inspection, then the inspection method can detect defects on silicon wafer surface, but light scattering in peripheral portions reduces detection sensitivity
Solution Approach 1:
The patent changes the optical parameters by specifying precise angle ranges: the angle between the light axis and wafer surface normal is set to 45°-75°, and the angle between the detection optical axis and wafer surface normal is set to 15°-75°. This parameter optimization reduces light scattering effects in peripheral portions while maintaining defect detection capability, thereby resolving the contradiction between detection sensitivity and light scattering.
2Measurement precision
If conventional inspection angles are used, then the inspection setup is simple, but detection sensitivity is insufficient
Solution Approach 1:
The patent specifies concrete angle parameter ranges (light axis angle: 45°-75°, detection optical axis angle: 15°-75°) that optimize detection sensitivity. By defining these specific parameter ranges, the patent achieves high detection sensitivity without requiring complex optical systems, as the solution lies in parameter optimization rather than structural complexity.
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
Enables high-sensitivity detection of slip dislocations on silicon wafers by optimizing the angles of light incidence and detection, improving contrast and visibility of defects.
Implementation Method 1
a light irradiation step of irradiating a surface of a silicon wafer with light from a light source; and a light detection step of detecting light reflected off the surface using a photodetector
Data Source
AI summary
In a side view, when an angle θ1 formed between the light axis of light incident on a surface of a silicon wafer and the surface (or an imaginary plane corresponding to the surface) is 67° to 78° and an angle formed between the surface of the silicon wafer (or an imaginary plane corresponding to the surface) and the detection optical axis of a photodetector is θ2, θ1−θ2 is −6° to −1° or 1° to 6°.