Near-Field Scanning Microwave Microscopy With Non-Contact Probe Control
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Solution Overview
Problem
Existing near-field microwave microscopy techniques face limitations in achieving high-resolution imaging and probe durability due to the need for continuous contact with the sample surface, which is unfavorable for in-line quality control and leads to probe wear.
Innovation Solution
A hybrid near-field scanning microwave microscope using an optical chromatic confocal displacement sensor to control the probe-sample distance, allowing non-contact imaging with a L-shaped probe and simultaneous microwave detection, enabling high-resolution topography and electrical property mapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the probe is brought into contact with the sample surface during imaging, then the imaging resolution is improved, but the probe wear increases and imaging rate decreases
Solution Approach 1:
The patent replaces the mechanical contact-based distance control with optical field-based control. An optical lever system detects probe displacement by measuring light reflection angle changes, enabling non-contact or minimal-contact operation while maintaining sub-micrometer positioning accuracy. This substitution eliminates mechanical wear from continuous contact while preserving imaging resolution.
Solution Approach 2:
The patent implements feedback control through optical lever detection and tuning fork-based shear force sensing. These systems continuously monitor probe-sample distance and provide real-time feedback to adjust the probe position, maintaining optimal imaging conditions without sustained contact. The feedback mechanism enables dynamic distance regulation that prevents probe wear while preserving measurement precision.
2Measurement precision
If the probe is brought into contact with the sample surface during imaging, then the imaging resolution is improved, but the imaging rate decreases
Solution Approach 1:
The patent replaces mechanical contact-based distance control with optical field-based control. An optical lever system detects probe displacement by measuring light reflection angle changes, enabling non-contact or minimal-contact operation while maintaining sub-micrometer positioning accuracy. This substitution eliminates mechanical wear from continuous contact while preserving imaging resolution.
Solution Approach 2:
The patent implements feedback control through optical lever detection and tuning fork-based shear force sensing. These systems continuously monitor probe-sample distance and provide real-time feedback to adjust the probe position, maintaining optimal imaging conditions without sustained contact. The feedback mechanism enables dynamic distance regulation that prevents probe wear while preserving measurement precision.
3Measurement precision
If the probe-sample distance is controlled with contact methods, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The patent replaces mechanical contact-based distance control with optical field-based control. An optical lever system detects probe displacement by measuring light reflection angle changes, enabling non-contact or minimal-contact operation while maintaining sub-micrometer positioning accuracy. This substitution eliminates mechanical wear from continuous contact while preserving imaging resolution.
Solution Approach 2:
The patent introduces optical fields and acoustic fields as intermediary measurement mechanisms. The optical lever uses light reflection as an intermediary to detect probe position without mechanical contact. The tuning fork uses acoustic vibration as an intermediary to sense distance through shear force changes. These intermediaries enable precise measurement while avoiding direct mechanical contact 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 fast scanning rates and reduced probe wear by maintaining the probe out of contact with the sample, suitable for in-line quality control and fault detection in manufacturing processes, with sub-100 nm resolution for surface topography and electrical property mapping.
Implementation Method 1
an optical unit adapted to focus light spots of different wavelengths at different positions along the optical axis, simultaneously on a portion of the probe and on a portion of the sample surface
Implementation Method 2
a spectrometer unit adapted to measure the intensity of the spot light reflection signal as a function of the light wavelength
Implementation Method 3
scanning probe imager, which operates with the probe in the close proximity to the surface of the sample being imaged during the image acquisition or mapping of sample properties
Data Source
AI summary
The invention describes a scanning probe imaging system with the probe held at a small distance from a sample (7) surface of the part during raster-scanning image acquisition. The interaction between the sample (7) and the probe's cantilever arm (17′) is achieved due to microwave near fields formed at the sharp probe tip (18). Due to the near fields, the electrical impedance of the probe depends on the distance between the probe and the sample (7) and on the sample electrical properties, both in the immediate vicinity of the probe tip (18). The microwave detection system senses the electrical impedance of the probe at a set microwave frequency. The probe-sample distance is set and controlled with the use of an optical chromatic confocal displacement sensor as well as with the signals of the microwave detection system.