Miniaturized AFM Probe Vertical Motion Mode
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Solution Overview
Problem
Conventional atomic force microscopy (AFM) probes with planar vibration modes face size constraints, limiting their use on biological samples and simultaneous optical and AFM analysis due to large footprint and sensitivity to surface irregularities, and struggle with high stiffness and low amplitude displacement, which affects image acquisition speed and quality.
Innovation Solution
A novel AFM probe design featuring a mechanical support structure anchored to the substrate, allowing a thin, sensitive probe with optimized resonance frequency and mechanical rigidity, minimizing parasitic modes and enabling high in-plane resonance frequencies and larger displacement amplitudes, suitable for both resonant and non-resonant modalities, including force curve imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional AFM probes with planar vibration modes are used, then mechanical stability is maintained, but the footprint is large and stiffness is high which limits displacement amplitude and image acquisition speed
Solution Approach 1:
The probe design transitions from conventional planar vibration modes to vertical motion modes, changing the dimension of operation. The tip moves perpendicular to the substrate plane, enabling high-frequency resonance (≥1 MHz) with larger displacement amplitudes while maintaining a compact footprint on the substrate surface.
Solution Approach 2:
The invention changes the vibration mode parameter from in-plane planar modes to vertical extensional modes. This parameter change enables the probe to achieve high resonance frequencies with larger displacement amplitudes, directly improving image acquisition rate while reducing the required footprint.
2Area of moving object
If the probe is miniaturized to reduce footprint, then space constraints are minimized, but mechanical stability and resonance frequency performance deteriorate
Solution Approach 1:
By moving the vibration mode to the vertical dimension (perpendicular to substrate), the probe achieves high mechanical stability through the stiff substrate support while the tip can be miniaturized on the substrate surface. The vertical motion mode decouples the footprint size from the mechanical stability requirements.
Solution Approach 2:
The probe is segmented into a substrate-mounted base structure and a protruding tip portion. The substrate provides mechanical stability and resonance frequency, while the miniaturized tip portion reduces footprint. This segmentation allows independent optimization of stability and size.
3Strength
If high stiffness is used to maintain mechanical stability, then probe rigidity is improved, but displacement amplitude decreases which affects imaging quality
Solution Approach 1:
Changing the vibration mode from in-plane bending to vertical extensional mode fundamentally alters the stiffness-displacement relationship. The vertical mode allows the probe to achieve high rigidity through the substrate while maintaining large displacement amplitudes, as the tip moves perpendicular to the stiff substrate plane rather than bending the substrate itself.
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 design achieves a high image acquisition rate with reduced stiffness, allowing for precise imaging of biological samples and combining optical and AFM analysis without the limitations of prior art, while maintaining mechanical stability and minimizing space constraints.
Implementation Method 1
When the probe tip is brought close to a surface, it is influenced by attractive or repulsive forces of a chemical, van der Waals, electrostatic, and/or magnetic nature.
Implementation Method 2
When the probe tip is brought close to a surface, it is influenced by attractive or repulsive forces of a chemical, van der Waals, electrostatic, and/or magnetic nature.
Implementation Method 3
Improved sensitivity can be achieved by vibrating the cantilever in one of its natural bending modes and observing the variations in resonance frequency induced by the gradients of these forces (dynamic AFM).
Data Source
Figure 1A
Figure 1B~1D
Figure 1G~1I
AI summary
An atomic force microscopy probe comprising an atomic force microscopy tip (PT1) oriented in a longitudinal direction (y), characterized in that: - the tip is arranged at one end of a movable or deformable sensing portion of the probe (SMS), connected to a support structure (SMM2), which is anchored to the main surface of the substrate; - the sensing portion and the support structure are planar elements, extending mainly in planes parallel to the main surface of the substrate; - the sensing portion is connected to the support structure via at least one element (ET1 - ET4) allowing said sensing portion to move or stretch in this direction; and - the tip, the sensing portion, and the support structure protrude from an edge (B) of the substrate in said longitudinal direction. An atomic force microscope comprising at least one such probe.