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Your Questions Answered: Optimizing SEM Sample Preparation with Broad Ion Beam Milling

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ArBlade 5000

Your Questions Answered: Optimizing SEM Sample Preparation with Broad Ion Beam Milling

Jun 19, 2025 3:41:32 PM

Achieving high-quality imaging in scanning electron microscopy (SEM) depends not just on the power of the microscope but also on how well the sample is prepared.

Traditional preparation methods like mechanical polishing and chemical etching can introduce artifacts, surface damage, and thermal effects, which compromise imaging accuracy.

This is where broad ion beam (BIB) milling comes in. Systems like the Hitachi IM4000II and ArBlade 5000 offer a contact-free, high-precision alternative to traditional techniques, ensuring artifact-free, high-resolution SEM imaging.

To help you understand how ion milling enhances your SEM workflow, we've compiled answers to some of the most frequently asked questions.

1
What is the temperature range of the sample surface close to the mask during the ion beam polishing process?

The temperature is highly dependent on the sample itself, as there isn't a built in temperature sensor for polishing. The sample's ability to absorb beam energy plays a significant role. Adjusting parameters through trial and error is the best approach to avoid overheating and melting effects.

2
Do you have a software model to calculate or simulate the temperature accumulated at the melting point?

No, there currently isn't a software model for this. The best method is empirical—adjusting parameters based on experience and observation. Factors such as beam energy, exposure time, and heat conductivity of the sample influence the temperature.

 
3
How does cryo-cooling help with heat-sensitive samples?

Cryo-cooling works by cooling the sample holder using liquid nitrogen and controlling the temperature with a sensor. But, because many heat-sensitive materials are poor thermal conductors, extra time is needed for the sample to reach the desired temperature.

4
How does broad ion beam (BIB) milling compare to focused ion beam (FIB) milling?

It depends on the application. FIB is excellent for precise, small-area cuts (10-20 microns), while BIB is much faster (up to 100 times faster) and better for preparing large cross-sections. FIB is ideal for targeting specific regions, but BIB is more effective for large-area sample preparation.

5
How does broad ion beam milling compare to plasma FIB?

Plasma FIB is about 10 times faster than traditional gallium FIB but still much slower than broad ion beam milling. For large-scale cross-sectioning, BIB is the more efficient option. Some workflows combine laser milling for rough cutting with BIB for fine polishing.

6
Why is a mask needed in cross-section milling?

The mask ensures a sharp edge and prevents the beam from hitting the sample perpendicularly, which would create a deep hole rather than a smooth cross-section. The mask material (typically titanium or tungsten carbide) is resistant to sputtering, ensuring controlled erosion.

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7
What techniques can be used to manage heat during ion milling?

Here are a few things you can try:

  • Lowering acceleration voltage to reduce beam energy.
  • Using pulsed (intermittent) milling to allow cooling between exposures.
  • Adding metal foil around the sample to improve heat conductivity and distribute heat more evenly.
8
Can ion milling be combined with laser processing?

Yes, laser milling is much faster but produces a rougher surface. Some workflows use laser milling for rough shaping, followed by BIB for fine polishing and surface refinement.

9
What are the advantages of using broad ion beam milling over traditional mechanical polishing?

BIB milling eliminates surface scratches, embedded debris and deformation that often occur with mechanical polishing. Since its a contact-free process, it doesn't introduce mechanical stress, making it ideal for delicate materials like composites, soft metals, and multilayer structures.

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Cross-section BSE image of composite carbon fibers embedded in epoxy

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Cross-section BSE image of composite carbon fibres embedded in epoxy

10
How does the choice of acceleration voltage affect the milling speed and surface quality?
  • High voltage (6-8 kV)
    Fast milling but rougher surfaces
  • Moderate voltage (3-5 kV)
    A balance between speed and precision
  • Low voltage (500 V - 2 kV)
    Slow milling but ultra-smooth surfaces, ideal for EBSD analysis
  • Lower voltages
    Particularly useful for final polishing steps where high surface quality is critical
11
What are the best practices for mounting samples before cross-section milling to minimize artifacts?
  • Ensure a flat mounting surface to prevent tilt.
  • Minimize overhang under the mask (≤100 µm) for better control.
  • Use strong, conductive adhesives to avoid sample shifting.
  • Eliminate air gaps between the sample and mask to prevent uneven milling.
  • Proper mounting ensures a clean, well-defined cross-section for SEM analysis.
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12
Can the IM4000II and ArBlade 5000 handle very thin or delicate samples without damage?

Yes, features like low-voltage milling, intermittent beam pulsing, and cryo-cooling allow for safe processing of ultra-thin films, polymers, and fragile specimens without deformation.

13
How does ion beam milling improve sample preparation for EBSD?

For electron backscatter diffraction (EBSD), sample surfaces must be strain-free and highly polished. Unlike mechanical polishing, which can introduce deformation, ion beam milling produces a smooth, undistorted surface, resulting in:

  • Sharper Kikuchi patterns
  • More accurate grain boundary analysis
  • Higher EBSD indexing success rates
14
What are the differences between using a standard vs. wide-area cross-section holder in the ArBlade 5000?
  • Standard holder
    Supports cross-sections up to 3 mm wide
  • Wide-area holder
    Expands milling width up to 10 mm
  • Multi-sample holder
    Handles multiple samples simultaneously and can reach
    40 mm width, perfect for large-scale material analysis.
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Standard holder

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Wide-area holder

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Multi-sample holder

15
How does intermittent beam pulsing improve results for soft or heat-sensitive materials?

Beam pulsing reduces heat build up by cycling the ion beam on and off.


This prevents:

  • Melting or phase changes in soft materials.
  • Structural deformation in temperature-sensitive samples.

It's particularly useful for battery separators, polymers, and biological specimens.

16
What are the key factors that influence curtaining effects, and how can they be minimized

Curtaining occurs when materials with different hardness erode at different rates.


To reduce this effect:

  • Use swing mode to move the sample slightly during milling.
  • Optimize acceleration voltage to balance material removal rates.
  • Ensure proper overhang under the mask for even milling.

These adjustments ensure flat, uniform cross-sections, even in complex multi-material samples.

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Conclusion

Enhance Your SEM results with Ion Milling

If you rely on scanning electron microscopy for research, quality control, or failure analysis, sample preparation is just as important as the microscope itself. The Hitachi IM4000II and ArBlade 5000 broad ion beam milling systems eliminate artifacts, improve surface quality, and ensure accurate high-resolution imaging - without the limitations of traditional preparation methods.

Book a live virtual demo to see how ion milling can enhance your imaging.
Speak with a Hitachi applications expert for tailored advice and system recommendations.
Learn more about the Hitachi IM4000II or ArBlade 5000.
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