Mastering Hard-to-Reach Surface Analysis with Correlative Microscopy

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Why Hard-to-Reach Surfaces Are Difficult to Measure

Accurate complex surface analysis is essential because the most critical insights are often hidden in the least accessible places—deep trenches, along sharp edges, or inside tiny cavities. These hard-to-reach regions present a persistent challenge for conventional Atomic Force Microscopy (AFM), where physical access, precise navigation, and risk of probe damage can severely limit both efficiency and data quality. A new integrated approach is changing that equation.

The Limits of Conventional AFM in Irregular Geometries

Traditional AFM workflows struggle when dealing with confined or complex sample geometries. The AFM tip, while incredibly precise, has limited manoeuvrability. This makes it difficult to reach features located on sidewalls, within cavities, or along steep edges. Even when access is possible, the risk of tip crash increases significantly in tight or obstructed regions, potentially damaging both the probe and the sample.

Localisation is another bottleneck. Identifying and returning to a specific region of interest (ROI)—especially when it is small or buried within an intricate structure—can be time-consuming and imprecise.

As a result, researchers often spend more time navigating than measuring, reducing throughput and slowing down analysis cycles.

A Unified Solution to Hard-to-Reach Surfaces

An integrated system that combines Scanning Electron Microscopy (SEM), AFM, and optional Energy-Dispersive X-ray Spectroscopy (EDS) offers a powerful solution to these challenges. By bringing these modalities together into a single platform, users gain access to a shared coordinate system that allows seamless navigation between imaging and measurement techniques.

Navigating Precisely with a Shared Coordinate System

The workflow begins with SEM, which provides a wide-field, high-resolution overview of the sample. This makes it easy to identify the ROI—even if it is hidden within a complex structure. Once selected, the system uses shared coordinates to guide the AFM probe directly to the target location with high precision.

Optimising Sample Orientation for AFM Probe Access

One of the key advantages of this approach is the ability to optimise sample orientation before measurement. By adjusting the stage or tilting the sample, users can ensure that the AFM tip has the best possible access to the feature of interest. This significantly reduces the risk of tip crash and improves measurement reliability.

Performing Controlled AFM Measurements with SEM Guidance

During the AFM approach, SEM imaging provides real-time visual guidance. This added layer of control allows for a careful, controlled descent of the probe—even in confined and tricky sample spaces. The result is a safer, more efficient process that minimises trial-and-error navigation.

From Measurement to Meaning

Once the AFM probe reaches the target site, high-resolution local measurements can be performed. These may include topography, roughness, or mechanical properties, depending on the application.

What sets this workflow apart is the ability to correlate AFM data directly with SEM images—and, if needed, EDS compositional information.

This multi-modal correlation enables materials analysis for hard to reach samples, giving a deeper understanding of the sample. For example, a surface feature identified in SEM can be quantitatively analysed with AFM, while EDS can reveal its elemental composition. Together, these insights provide a comprehensive picture that would be difficult to achieve with separate instruments.

Real-World Examples of Measuring Complex Surfaces

This approach is particularly valuable in industrial contexts, where speed, accuracy, and reliability are critical. Components such as gear wheels, dental drills, and fibre. Coating Uniformity​-based materials often feature complex geometries that are difficult to analyse using conventional methods. With correlative microscopy, even the most inaccessible features can be examined with confidence.

Deep dive into more applications

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FusionScope Work-Flow

1. SEM Overview to identify region of interest​
2. Precise Navigation to target area using shared coordinates​
3. Stage/Sample orientation optimised for probe access​
4. Controlled AFM approach with SEM guidance​
5. Local AFM measurements at selected site​
6. Correlation of AFM, SEM, (and EDS) data for full interpretation​

 

Measuring Coating Uniformity on Irregular Geometries

Coating uniformity is another key application. Ensuring consistent coverage on irregular surfaces is essential in many manufacturing processes. The ability to analyse difficult samples by combining structural, topographical, and compositional data in a single workflow makes it easier to:

• detect defects
• optimise processes
• maintain quality standards

How This Workflow Improves Industrial Quality Control and Efficiency

For industrial analytical services, the benefits are clear…

… A unified SEM-AFM-EDS workflow:

• reduces the need for multiple instruments
• shortens analysis time
• improves data consistency

This translates into faster characterisation of challenging samples and more informed decision-making in quality control and process optimisation.

In a field where the smallest details can have the biggest impact, the ability to reach—and understand—every corner of a sample is a game changer. Correlative microscopy doesn’t just solve the problem of access; it transforms it into an opportunity for deeper complex surface analysis.

App Note:  Bone Tissue