Probe Shadow Alignment for Soft Contact in Tilted Microscopy

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Solution Overview

Problem

Conventional contact detection methods in microscopes, such as FIB and electron microscopes, face challenges in softly and certainly approaching a sample without special detection means, especially when dealing with insulators or conductive materials with oxide films, and are prone to delayed detection leading to sample damage.

Innovation Solution

A method and apparatus utilizing a charged particle beam microscope to calculate the direction and distance to a sample position by observing the shadow of the probe, allowing precise movement to within microns, and applying a voltage for luminance changes to visually confirm contact, enabling soft and certain contact without additional detection means.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If contact detection is performed by visual observation of microscope image, then the operation is simple, but the detection is vague and delayed causing sample damage

Engineering Contradiction:

Improveoperation simplicityVSAvoidcontact detection accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent introduces an ammeter as an intermediary device to detect contact between the probe and sample. The ammeter measures electric current flow, serving as a mediator that translates the physical contact event into a quantifiable electrical signal, thereby enabling precise and timely contact detection without direct visual observation

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical/visual observation system with an electrical detection system. Instead of relying on visual inspection of microscope images, the system uses electrical current measurement through the ammeter to detect contact, substituting a more sensitive and precise electrical measurement method for the inadequate visual method

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If probe voltage is applied and current change is monitored to detect contact, then contact detection is certain, but additional electric source and detection means are required

Engineering Contradiction:

Improvecontact detection accuracyVSAvoiddetection system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The probe serves multiple functions: it acts as both the operational tool for sample manipulation and as the detection element for contact sensing. The same probe structure is used for both applying voltage and detecting contact through current measurement, eliminating the need for separate detection means and reducing overall system complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses its own operational components (the probe and existing voltage source) to perform the detection function. The probe's electrical connection to the sample, which is necessary for its operational function, simultaneously serves as the detection mechanism, allowing the system to self-diagnose contact status without external detection equipment

Inventive Principle:

Principle #25Self-service

3Productivity

If probe approaches sample without precise control, then the operation is simple, but the sample and probe tip are injured due to delayed detection

Engineering Contradiction:

Improveoperation speedVSAvoidsample safety

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the ammeter continuously monitors electric current flow and provides real-time information about probe-sample contact status. This feedback loop allows the operator to immediately detect contact and adjust the probe position, preventing excessive force application and ensuring sample safety while maintaining operational speed

Inventive Principle:

Principle #23Feedback

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 soft and certain contact of the probe with the sample by precisely calculating and adjusting the probe's position based on microscope images at different tilt angles, allowing for safe and efficient operation even with irregular surfaces or conductive-insulator combinations.

Implementation Method 1

a charged particle beam is irradiated to a sample image containing a probe image obtained by detecting secondary particles or reflected particles discharged by the charged particle beam irradiation

Methodology Applied

Scientific EffectSecondary electron emission: Electron Beam

Implementation Method 2

a micro-actuator comprising a piezoelectric element is monolithically fixed to the stage

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS7511269B2Method of approaching probe and apparatus for realizing the same

Publication Date: 2009.03.31 HITACHI HIGH TECH SCIENCE CORP

AI summary

A method of approaching a probe to a target position on a sample mounted on a sample stage tilted at a preselected tilt angle about a tilt axis of the sample stage. A distance between the tip of the probe and the target position of the sample is observed with a charged particle beam microscope while approaching the tip of the probe to the target position on the sample. The probe is moved in a direction so that on a display of the charged particle beam microscope, the tip of the probe and the tip of a shadow of the probe on the sample coincide at the target position on the sample.