Scanning Probe Microscope Steep Incline Measurement
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Solution Overview
Problem
Current scanning probe microscopes face challenges in accurately measuring shapes of samples with high aspect ratios and steep inclines due to probe slippage and wear, leading to distorted measurements and reduced stability.
Innovation Solution
A scanning probe microscope method that involves retracting and approaching the probe for each measuring point, combined with high-frequency, atomic-order vibrations to prevent slippage, and the use of a high-sensitivity proximity sensor for precise contact detection, allowing for accurate shape measurement of semiconductor samples with steep steps without damaging the sample.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the probe continuously contacts the sample surface to maintain measurement stability, then measurement precision is improved, but probe wear increases and measurement speed decreases
Solution Approach 1:
The probe performs periodic approach-retract cycles rather than continuous contact. The probe approaches the sample, measures at discrete points, retracts, and repeats. This periodic action reduces cumulative wear while maintaining measurement precision through repeated sampling at each point.
Solution Approach 2:
The measurement process maintains continuous useful action through automated feedback control. The proximity sensor continuously monitors probe-sample distance and the control system automatically adjusts probe position to maintain optimal contact force, ensuring continuous measurement capability without manual intervention.
2Measurement precision
If the probe applies sufficient contact force to prevent slippage on steep inclines, then measurement precision is improved, but probe and sample damage increases
Solution Approach 1:
The probe applies partial contact force sufficient to prevent slippage during measurement, rather than maximum contact force. The proximity sensor enables precise control to apply only the minimum necessary force to maintain measurement accuracy, avoiding excessive force that would cause damage to the probe or soft/brittle sample.
Solution Approach 2:
The system replaces traditional mechanical force control with optical/electromagnetic sensing control. The proximity sensor detects the probe-sample interaction through non-contact means, allowing the control system to regulate contact force electronically rather than through mechanical feedback, enabling more precise and gentler contact control.
3Productivity
If the probe moves at high speed across the sample surface, then productivity is improved, but measurement precision deteriorates due to inertia and vibration
Solution Approach 1:
The measurement process is segmented into discrete approach-retract cycles at each measurement point rather than continuous scanning. This segmentation allows the probe to accelerate quickly between points (improving productivity) while maintaining precise control during the brief measurement contact period (maintaining precision).
Solution Approach 2:
The system dynamically adjusts probe motion parameters based on real-time feedback from the proximity sensor. The control system modulates approach speed, contact force, and dwell time at each point to optimize both measurement precision and overall throughput, adapting to local sample characteristics.
4Measurement precision
If the probe uses high-frequency vibration to prevent slippage, then measurement precision is improved, but probe wear increases
Solution Approach 1:
The system replaces mechanical vibration-based slippage prevention with electromagnetic/optical sensing control. The proximity sensor detects probe-sample contact through non-mechanical means (electromagnetic or optical fields), eliminating the need for high-frequency mechanical vibrations that cause wear, while maintaining accurate contact detection.
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 method enables high-speed, high-accuracy shape measurement of soft, brittle materials and patterns with steep steps, reducing probe wear and improving measurement throughput by maintaining contact without dragging the probe, thus achieving stable and precise results.
Implementation Method 1
causing the probe to minutely vibrate with amplitude of the atomic order and at a high frequency
Implementation Method 2
uses a measuring method of repeating retracting/approaching of a probe for each measuring point... detecting contacts at a high speed and with high sensitivity by causing the probe to minutely vibrate
Data Source
AI summary
The present invention provides a method of using an accurate three-dimensional shape without damaging a sample by making a probe contact the sample only at a measuring point, lifting and retracting the probe when moving to the next measuring point and making the probe approach the sample after moving to the next measuring point, wherein high frequency/minute amplitude cantilever excitation and vibration detection are performed and further horizontal direction excitation or vertical/horizontal double direction excitation are performed to improve the sensitivity of contacting force detection on a slope of steep inclination. The method uses unit for inclining the probe in accordance with the inclination of a measurement target and a structure capable of absorbing or adjusting the orientation of the light detecting the condition of contact between the probe and sample after reflection on the cantilever, which varies a great deal depending on the inclination of the probe.