Phase-Based Current Path Detection in Semiconductor Inspection
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Solution Overview
Problem
Existing optical probing technologies for inspecting metal surfaces struggle to accurately acquire current paths due to noise components like unevenness and scratches on magneto-optical crystals, leading to inaccurate amplitude image-based current path detection.
Innovation Solution
The method involves applying a stimulus signal to the measurement target, irradiating a magneto-optical crystal with light, detecting the reflected light, and generating phase image data based on the phase difference between the reference and detection signals to accurately identify the current path, which is less susceptible to noise influences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If amplitude image-based current path detection is used, then the detection method is simple, but the measurement precision deteriorates due to noise components from magneto-optical crystal unevenness and scratches
Solution Approach 1:
The patent changes the detection parameter from amplitude (intensity) to phase. By using phase image data based on phase difference between reference and detection signals, the system achieves accurate current path detection that is not affected by noise components such as magneto-optical crystal unevenness and scratches, while maintaining operational simplicity through automated phase-based processing
Solution Approach 2:
The patent substitutes the conventional amplitude-based detection mechanism with a phase-based detection mechanism. This replacement uses phase difference information from interferometric measurement to identify current paths, eliminating the sensitivity to surface noise that plagues amplitude-based methods
2Measurement precision
If phase difference-based current path detection is used, then the measurement precision improves, but the device complexity increases due to additional signal processing requirements
Solution Approach 1:
The patent introduces phase difference as an intermediary parameter between the optical measurement and current path identification. By using phase difference between reference and detection signals as the intermediate step, the system achieves high-precision current path detection while the complexity is managed through systematic phase-based processing rather than direct amplitude analysis
3Productivity
If amplitude image is used for current path acquisition, then the processing speed is fast, but the reliability deteriorates due to noise influence from magneto-optical crystal defects
Solution Approach 1:
The patent changes the detection parameter from amplitude to phase, which fundamentally alters the noise characteristics of the measurement. Phase-based detection provides reliable current path acquisition that is immune to magneto-optical crystal defects, while maintaining processing efficiency through automated phase difference calculation and image generation
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 allows for precise acquisition of current paths by distinguishing between specific phase differences in current path and non-current path areas, enhancing identification accuracy and robustness against noise components.
Implementation Method 1
a method of arranging a magneto-optical (MO) crystal to face a light irradiation surface of the measurement target and detecting reflected light according to a magneto-optical effect of the MO crystal
Implementation Method 2
detecting light reflected from the magneto-optical crystal according to the irradiated light
Data Source
AI summary
An inspection apparatus includes a tester unit that applies a stimulus signal to a semiconductor apparatus, an MO crystal arranged to face a semiconductor apparatus, a light source that outputs light, an optical scanner that irradiates the MO crystal with light output from light source, a light detector that detects light reflected from the MO crystal arranged to face the semiconductor apparatus D and outputs a detection signal, and a computer that generate phase image data based on a phase difference between a reference signal generated based on a stimulus signal and the detection signal, the phase image data including a phase component indicating the phase difference, and generates an image indicating a path of a current from the phase image data.