How SEM Imaging is Used?

Automating scanning electron microscopy (SEM) imaging can save time for researchers who frequently use an SEM, and automation can be used in many different applications. This article will explore a real world application of automated SEM imaging – testing the Laser-Induced Damage Threshold (LIDT).

Powerful laser light can damage the optical components of a system, such as fibers, optical coatings and mirrors. To ensure systems are operating effectively it is important to determine what laser power the system can cope with, and what laser power can damage the system or alter its optical behavior.

Figure 1: BSD SEM image of laser-induced damage on an optical coating.

LIDT tests are used to determine the extent of damage a specific laser dose causes. LIDT tests involve exposing an optical component to different wavelengths and strengths of laser light in a grid pattern.

Following this exposure, optical and SEM microscopy is used to examine the component for damage. One sample could contain hundreds of different grid points for individual inspection that would take a long time to inspect manually. For this reason, running automated LIDT tests through an SEM can save a significant amount of time.

Taking Automatic SEM Images

Through a programmable interface, scripts can be written for the automatic acquisition of images using an SEM for each point in the LIDT grid. The script is equipped with the grid coordinates created by the laser. Following calibration of the stage the system can then automatically image each point at the required magnification.

Figure 2: User interface of the LIDT scan script: the small red and green dots represent points where the optical coating was exposed to laser light.

The captured images are saved in a dedicated folder for later inspection. If specific grid locations must be inspected further this can be easily identified via the user interface. Using this method allows researchers to dedicate more time to analysis, with less time required to operate image acquisition.

Automating SEM imaging saves up a huge amount of time, meaning all researchers have to do now is select each image and check for damage.

This information has been sourced, reviewed and adapted from materials provided by Phenom-World BV.

For more information on this source, please visit Phenom-World BV.