Stationary Ion Beam Intersection for Electron Microscopy Sample Preparation

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Solution Overview

Problem

Current ion beam etching methods for electron microscopy fail to achieve high cutting depths with short preparation times and excellent sample quality, particularly in the semiconductor industry and microelectronics, where sample structure integrity and uniformity are critical.

Innovation Solution

The method employs at least three locally fixed ion beams directed at an angle onto the sample surface, forming an intersection zone without moving the sample or ion beams, allowing for high-resolution observation and control during the etching process, with adjustable parameters such as beam angle, energy, and position to optimize cutting speed and surface quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single ion beam or conventional ion source is used for etching, then the etching process is simple to operate, but high cutting depths with short preparation times cannot be achieved

Engineering Contradiction:
Improvecutting depth per unit timeVSAvoidion beam arrangement complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention divides a single ion beam into multiple parallel ion beams (at least three) that strike the sample surface simultaneously at different locations. This segmentation allows parallel etching of multiple regions, dramatically increasing the cutting depth per unit time while maintaining operational simplicity through automated beam positioning.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention combines multiple ion beams into a coordinated system that operates simultaneously on the sample surface. By merging the etching actions of multiple beams under unified control, the system achieves high productivity without requiring complex manual intervention, as the beams are synchronized to work together efficiently.

Inventive Principle:
Principle #5Merging (Combining)

2Manufacturing precision

If the sample is moved or oscillated during etching to achieve uniform removal, then etching uniformity improves, but the preparation time increases and process complexity increases

Engineering Contradiction:
Improveetching uniformityVSAvoidpreparation time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The invention employs dynamic positioning of multiple ion beams that can be independently adjusted during the etching process. The beams are positioned and moved in a coordinated manner to uniformly etch the sample surface without requiring physical movement or oscillation of the sample itself, thereby reducing preparation time while maintaining etching uniformity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention replaces the mechanical oscillation or movement of the sample with a controlled positioning and movement system for the ion beams themselves. By substituting sample mechanical motion with beam positional control, the system achieves uniform etching without the time loss and complexity associated with sample manipulation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If multiple ion sources are used to increase removal rate, then productivity improves, but device complexity and control difficulty increase

Engineering Contradiction:
Improvematerial removal rateVSAvoidion source arrangement complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention segments a single controllable ion source into multiple parallel ion beams through beam splitting optics or magnetic fields. This approach achieves the material removal rate of multiple sources while maintaining the simplicity of a single source control system, as all beams originate from and are controlled by one ion source.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention makes a single ion source perform the function of multiple ion sources by generating multiple parallel beams from it. This multi-functional approach allows one source to accomplish what would traditionally require multiple sources, thereby increasing productivity without proportionally increasing device complexity or control difficulty.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 enables high cutting depths with short preparation times, maintaining sample integrity and reducing etching selectivities, thus achieving high-efficiency and reliable sample preparation with improved surface quality.

Implementation Method 1

material is removed from the sample surface by ion etching

Methodology Applied
Scientific EffectIon etching: Sputtering

Data Source

PatentEP2132550B1Method for the production of a sample for electron microscopy
Publication Date: 2012.11.07 LEICA MIKROSYSTEME GMBH
  • EP2132550B1 patent drawingFigure 1~2
  • EP2132550B1 patent drawingFigure 3~4
  • EP2132550B1 patent drawingFigure 5a~5c

AI summary

A probe (1) for electron microscopy is cut from a solid material. A sample surface (3) is configured on the same, which is treated with an ion beam (J) at a predetermined angle of incidence such that the material is ablated from the sample surface (3) by means of etching until the desired observation surface (20) is exposed on the sample (1) in the region of the incidence zone (4) of the ion beam (J), which enables the viewing (12) of the desired region of the sample (1) using an electron microscope. For this purpose, at least two stationary ion beams (J1, J2) are guided onto the sample surface (3) at a predetermined angle (a) in alignment with each other such that the ion beams (J1, J2) at least come in contact with each other on the sample surface (3), or cross each other, and form an incidence zone (4) in that location, and that both the sample (1) and the ion beams (J1, J2) are not moved, and thus are operated in a stationary manner.