Ion Beam Etching for TEM Sample Preparation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current methods for preparing samples for transmission electron microscopy (TEM) are inefficient, requiring skilled operators and high-cost equipment, and struggle to produce large, thin, electron-transparent areas with minimal damage and in a timely manner, especially for 3D integrated microelectronic components.

Innovation Solution

A method involving the creation of a terrace formation zone on the sample surface by producing notches with oblique flanks, followed by ion beam etching with grazing incidence, which selectively removes material to achieve a thin, electron-transparent examination area with minimal damage and precise control over the sample thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If FIB processing is used to produce electron-transparent areas, then manufacturing precision is improved, but device complexity and acquisition costs increase significantly

Engineering Contradiction:

Improveelectron transparency qualityVSAvoidsystem complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces the expensive, complex FIB system with a more affordable ion beam etching system that achieves comparable results for the specific application of creating electron-transparent areas in TEM sample preparation

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the processing parameters by using ion beam etching with controlled angles and energies to achieve the desired electron transparency without requiring the high precision and complexity of FIB processing

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If FIB processing is used, then manufacturing precision is improved, but productivity decreases due to lower ablation rates

Engineering Contradiction:

Improveelectron transparency qualityVSAvoidsample preparation speed

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent optimizes ion beam etching parameters including angle of incidence, ion energy, and processing time to achieve both high precision electron transparency and improved productivity through higher ablation rates compared to FIB

Inventive Principle:

Principle #35Parameter changes

3Productivity

If broad ion beam processing is used, then productivity is improved, but manufacturing precision decreases compared to FIB

Engineering Contradiction:

Improvesample preparation speedVSAvoidelectron transparency quality

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies local quality control by using masks and controlled ion beam angles to ensure that only the specific areas requiring electron transparency are processed with high precision, while other areas can be processed more rapidly

Inventive Principle:

Principle #3Local quality

4Device complexity

If mechanical pre-thinning is used, then device complexity is reduced, but manufacturing precision and reliability decrease due to artifacts

Engineering Contradiction:

Improveprocessing simplicityVSAvoidsample quality

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent replaces mechanical pre-thinning processes with ion beam etching, substituting mechanical contact with a non-contact ion beam process that eliminates mechanical artifacts while maintaining simplicity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 allows for the efficient and reproducible production of large, electron-transparent examination areas with minimal material damage, enabling the examination of target areas with high precision and stability, suitable for TEM and potentially other microstructure diagnostics techniques.

Implementation Method 1

an ion beam is irradiated with grazing incidence onto the surface in such a way that material in the region of the terrace formation zone is removed

Methodology Applied

Scientific EffectIon beam etching: Sputtering

Implementation Method 2

a laser influence layer is present which is to be taken into consideration

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Data Source

PatentEP3153838B1Method for preparing a sample for the microstructure diagnosis and sample for micro structure diagnosis

Publication Date: 2022.07.06 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV

Figure 1~2D
Figure 3A~3C
Figure 4A~4B

AI summary

In a method for preparing a sample for microstructure diagnostics, a sample section (PA) is prepared from a sample body by material removal. Subsequently, an examination area is created on the sample section, which comprises a target area (ZB) to be examined.The process comprises the following steps: creating a terrace formation zone (TBZ) encompassing the target area on at least one surface of the sample section, wherein, for the creation of the terrace formation zone, at least one notch (K) with flanks (F1, F2) running obliquely to the surface is produced next to the target area by material-removing abrasive blasting; and removing material from the sample section (PA) in the area of the terrace formation zone (TBZ) by means of an ion beam (IB), which is blasted onto the surface at a grazing incidence oblique to a direction of the notch (K) such that the target area (ZB) lies behind the notch in the direction of incidence of the ion beam (IB).