Backside Absorbing Layer Microscopy for Nano-Object Positioning

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Solution Overview

Problem

Current methods for precisely positioning micro- or nano-objects above a flat support, especially in scanning probe microscopy and nano-manufacturing, face challenges due to low visibility and size limitations, making it difficult to separate probe position from surface interaction parameters, particularly in electrochemical microscopy where the signal is sensitive to surface properties rather than distance.

Innovation Solution

The use of an optical technique called Backside Absorbing Layer Microscopy (BALM) with an absorbing antireflection layer on a transparent substrate enhances contrast, allowing visual control and precise positioning of micro- or nano-objects by analyzing optical interference patterns or light intensity reflected through the substrate, enabling accurate measurement of distance and orientation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional microscopy is used to observe micro- or nano-objects, then the objects can be visualized to some extent, but the visibility is insufficient and positioning precision deteriorates

Engineering Contradiction:
Improvevisibility of micro- or nano-objectsVSAvoidpositioning precision
Core Design Contradiction:
Illumination intensityVSMeasurement precision

Solution Approach 1:

The patent introduces an absorbing layer as an intermediary element between the light source and the micro- or nano-object. This layer mediates the optical interaction by creating enhanced contrast through absorption, allowing the object to be visualized more clearly without directly illuminating it in a way that would compromise positioning precision. The absorbing layer acts as a mediator that converts weak optical signals into detectable contrast patterns.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent utilizes optical contrast changes (analogous to color changes in the broader sense of optical property changes) by employing an absorbing layer that creates distinct optical signatures. The layer modifies the optical properties of the system by absorbing specific wavelengths and creating interference patterns, which manifest as visible contrast variations that enable precise positioning without direct illumination of the object itself.

Inventive Principle:
Principle #32Color changes

2Measurement precision

If the probe-to-surface distance is measured using the probe signal itself, then measurement can be performed, but the measurement precision deteriorates because the signal is sensitive to surface properties rather than distance

Engineering Contradiction:
Improvedistance measurement precisionVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces an absorbing layer as an intermediary reference element that enables distance measurement through optical interference patterns. This mediator allows the measurement of probe-to-surface distance by creating a reference optical field that interferes with the field reflected from the surface, providing a distance-dependent signal that is independent of surface properties. The absorbing layer serves as a stable reference that decouples the measurement from surface property variations.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If micromanipulators are used to manipulate micro- or nano-objects, then positioning can be performed, but the bulkiness of the manipulators deteriorates visibility

Engineering Contradiction:
Improvemanipulation capabilityVSAvoidvisibility
Core Design Contradiction:
Ease of operationVSIllumination intensity

Solution Approach 1:

The patent extracts the visualization function from the manipulation system by introducing a separate optical measurement system with an absorbing layer. This separation allows the micromanipulator to perform its manipulation function without interfering with the visualization process. The absorbing layer and optical system are taken out as an independent subsystem that provides visibility without adding bulk to the manipulation apparatus.

Inventive Principle:
Principle #2Taking out (Extraction)

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 approach allows for precise and efficient positioning of micro- or nano-objects, improving the quality of signals in scanning probe microscopy and facilitating the assembly of nanostructures by enhancing visibility and control over distance and orientation, thereby overcoming the limitations of existing methods.

Implementation Method 1

at least one optically absorbing layer, adapted to behave as an anti-reflective coating when illuminated at normal incidence at a wavelength of illumination λ through said transparent substrate

Methodology Applied
Scientific EffectAnti-reflective coating: Anti-Reflective Coating

Implementation Method 2

observing it in specular reflection also through said transparent substrate and said optically absorbing layer

Methodology Applied
Scientific EffectSpecular reflection: Reflection

Implementation Method 3

characterizing a parameter chosen from the distance between the micro- or nano-object and the optically absorbing layer and the inclination of the micro- or nano-object relative to the optically absorbing layer, by analyzing an optical interference pattern or a light intensity reflected by said layer observed through said substrate

Methodology Applied
Scientific EffectOptical interference: Interference

Data Source

PatentEP3443362B1Method and device for positioning a micro- or nano-object under visual control
Publication Date: 2021.10.06 CENT NAT DE LA RECH SCI (C N R S)
  • EP3443362B1 patent drawingFigure 1~2A
  • EP3443362B1 patent drawingFigure 2B~4
  • EP3443362B1 patent drawingFigure 3

AI summary

Method for moving a micro- or nano-object (SLM, F2D2) into position above a planar holder (SAC) under visual observation, characterized in that: said micro- or nano-object is submerged in a transparent medium, called the ambient medium (MA), having a refractive index n3; said planar holder comprises a transparent substrate (SS) of refractive index n0>n3 on which is deposited at least one optically absorbent layer (CA) that is able to behave as an antireflection coating when illuminated at normal incidence at an illuminating wavelength λ through said substrate; and the visual observation comprises illuminating said micro- or nano-object at least at said wavelength λ through said substrate, and also observing it through said substrate. Application of such a method to scanning probe microscopy and to the assembly of nanostructures.