Scanning Probe Microscopy Interferometer for Faster Nanostructure Mapping
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Solution Overview
Problem
Scanning probe microscopy systems face challenges in achieving high throughput and accuracy while maintaining a compact footprint, particularly in applications requiring rapid scanning of macroscopic surfaces with nano-scale resolution.
Innovation Solution
A scanning probe microscopy system utilizing a common path optical sensor with an interferometer to directly measure both the dynamic and static behavior of the probe tip, employing a partially reflecting element and directional optics to provide a reference and sensing optical signal, enabling precise distance measurement through interferometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a microscopic probe is used to achieve high resolution and accuracy in mapping nanostructures, then measurement precision is improved, but productivity decreases due to significant processing time required for macroscopic surfaces
Solution Approach 1:
The optical signal is segmented into multiple fractions (reference fraction and sensing fraction) that travel different paths but are recombined at the interferometer. This allows simultaneous measurement of multiple probe positions, enabling parallel acquisition of topography data and significantly increasing throughput while maintaining nanometer-scale resolution
Solution Approach 2:
The patent replaces indirect mechanical feedback methods with direct optical interferometric measurement. By using optical paths instead of mechanical sensing, the system achieves faster measurement speeds without sacrificing precision, resolving the contradiction between high resolution and high throughput
2Device complexity
If indirect feedback methods are used to measure probe tip motion, then device complexity is reduced, but measurement precision deteriorates due to errors in feedback loops
Solution Approach 1:
The patent introduces an interferometer as an intermediary device that directly measures probe tip position through optical path length differences. This intermediary optical measurement system eliminates errors associated with indirect mechanical feedback while maintaining relatively simple device architecture
Solution Approach 2:
The patent substitutes mechanical feedback sensing with optical interferometric measurement. The optical method provides direct, error-free position measurement without the complications of mechanical feedback loops, achieving high precision while keeping the overall system manageable in complexity
3Volume of moving object
If a compact scan head design is implemented, then device footprint is reduced, but measurement precision may deteriorate due to space constraints on optical components
Solution Approach 1:
The patent implements a nested optical path configuration where the reference optical path and sensing optical path are interleaved or nested within each other. This allows both paths to coexist in a compact volume without interfering with each other, maintaining measurement precision while minimizing scan head footprint
Solution Approach 2:
The patent uses three-dimensional optical path routing to accommodate both reference and sensing beams within a compact scan head. By utilizing vertical and lateral spatial dimensions efficiently, the design achieves accurate interferometric measurement in a minimized volume
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
The system allows for faster and more accurate scanning by directly measuring probe tip motion, reducing errors associated with indirect feedback methods and enabling smaller, more efficient scan heads for increased throughput and precision in nanostructure mapping.
Implementation Method 1
a partially reflecting element, configured to reflect a reference fraction of the optical signal for providing a reference signal
Implementation Method 2
an interferometer for enabling the sensed signal to interfere with the reference signal for providing one or more output signals
Data Source
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AI summary
The present document relates to a scanning probe microscopy system and method for mapping nanostructures on the surface of a sample. The system comprises a sample support structure, a scan head including a probe comprising a cantilever and a probe tip, and an actuator for scanning the probe tip relative to the sample surface. The system also includes an optical source, and a sensor unit for obtaining a sensor signal indicative of a position of the probe tip. The sensor unit includes a partially reflecting element for reflecting a reference fraction and for transmitting a sensing fraction of the optical signal. It further includes directional optics for directing the sensing fraction as an optical beam towards the probe tip, and for receiving a reflected fraction thereof to provide a sensed signal. Moreover the sensor includes an interferometer for providing one or more output signals, and signal conveyance optics for conveying the sensed signal and the reference signal to the interferometer. The directional optics is configured for directing the sensing fraction such that at least a part of the sensing fraction is reflected by the probe tip such as to form the reflected fraction.