Probe Contact Detection Using Multi-Frequency S-Parameter Outliers
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Solution Overview
Problem
Existing techniques face challenges in accurately determining whether a probe is in contact with a contact pad or if a coaxial connector or waveguide is in a connection failure state, particularly with complex structures like dummy-fill structures.
Innovation Solution
A method using a control device that measures S-parameters at multiple frequencies, calculates a coefficient matrix for fitting a predetermined function matrix, and determines contact or connection failure based on the local outlier factor (LOF) calculated from this matrix.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If S-parameter change detection is used to determine probe contact position, then the technique works well for simple structures, but it fails to accurately determine contact position for complex structures with dummy-fill
Solution Approach 1:
The patent segments the S-parameter frequency characteristic into multiple frequency points and analyzes the local outlier factor at each segment. By dividing the frequency spectrum and examining localized deviations rather than relying on overall S-parameter changes, the method can distinguish contact signals from dummy-fill interference patterns, enabling accurate contact detection on complex structures.
Solution Approach 2:
The patent measures S-parameters at multiple frequency points beyond the minimum single-frequency measurement. This excessive measurement approach provides redundant information that enables statistical analysis (local outlier factor calculation) to differentiate between genuine contact signals and artifacts from dummy-fill structures, thereby improving measurement reliability.
2Measurement precision
If manual determination of probe contact is used, then contact position can be identified, but the process is time-consuming and lacks automation
Solution Approach 1:
The system performs automatic contact determination by calculating the local outlier factor from measured S-parameter data and comparing it against a threshold. This self-service mechanism eliminates the need for manual inspection or intervention, enabling the measurement system to autonomously identify contact positions and states while maintaining high accuracy through statistical analysis.
Solution Approach 2:
The patent implements a feedback mechanism where the calculated local outlier factor is continuously compared against a predetermined threshold to determine contact state. This automated feedback loop enables real-time contact detection and positioning without manual intervention, significantly reducing measurement time while maintaining precision.
3Measurement precision
If additional sensors or high-resolution microscopes are installed to improve contact detection, then measurement accuracy improves, but device complexity and cost increase
Solution Approach 1:
The patent replaces mechanical/optical detection systems (such as high-resolution microscopes or additional sensors) with an electromagnetic field-based detection method. By analyzing S-parameter frequency characteristics and calculating local outlier factors, the system achieves contact detection accuracy without requiring additional mechanical or optical components, thereby maintaining system simplicity.
Solution Approach 2:
The patent makes the existing S-parameter measurement system multi-functional by enabling it to perform both electrical characterization and contact detection functions. The same vector network analyzer used for measuring device under test characteristics is also used to detect probe contact positions through local outlier factor analysis, eliminating the need for separate detection systems and reducing overall device complexity.
Data Source
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AI summary
The present invention makes it possible to determine whether a state in which a probe is contacting a prescribed target or a state in which there is a connection failure between a coaxial connector or a waveguide and the prescribed target exists. A determination method according to the present application includes: (A) a step for measuring, at a plurality of frequencies, an S-parameter at the current probe location or in the current coaxial connector or waveguide connection state; (B) a step for calculating a coefficient matrix for fitting a prescribed function matrix to the measured S-parameter frequency properties; (C) a step for calculating a first local outlier factor on the basis of the calculated coefficient matrix; and (D) a determination step for determining, on the basis of the relationship between a threshold and the calculated first local outlier factor, whether a first state in which the probe is contacting the prescribed target, or a second state in which there is a connection failure between the coaxial connector or the waveguide and the prescribed target exists.