CEA‑Leti has developed a nanometre‑scale strain‑mapping service that directly addresses the need for local, quantitative deformation measurement in advanced semiconductor devices. Strain engineering is critical in modern chips, and the institute’s platform uses transmission electron microscopy (TEM) combined with precession electron diffraction (PED) to deliver highly accurate maps.

In standard electron diffraction, a fixed‑angle beam often generates complex patterns dominated by dynamic scattering. PED overcomes this by rotating the beam in a conical sweep, recording diffraction data across dozens of orientations. The result is cleaner, information‑rich patterns that can be transformed into precise strain maps.

The process begins with the preparation of ultra‑thin lamellae—chip cross‑sections about 80 nm thick—using focused ion beam (FIB) milling. The specimen is then transferred to a TEM equipped with a PED module, where scanning diffraction measures crystal lattice parameters with high spatial resolution across different device regions. The resulting strain maps achieve a spatial resolution of 1 nm and a precision of approximately 0.02%, placing CEA‑Leti among the world leaders in nanoscale metrology.

To increase throughput, the technique has been streamlined and accelerated wherever possible, cutting turnaround times for characterization requests. Three TEMs are now outfitted for PED, enabling the lab to process a larger volume of samples and opening the service to more qualified microscopists.

The transition from experimental technique to routine service was made possible by the combined expertise of a multidisciplinary team. According to Nicolas, who helped lead the effort, the partnership between fundamental research and application‑driven engineering was key to turning a laboratory methodology into a practical, high‑volume characterization platform.

That is why at CEA-Leti we have been working in recent years on the local and quantitative measurement of material deformations, which are at the heart of today’s cutting-edge devices.​​​

CEA‑Leti's strain‑mapping service uses transmission electron microscopy (TEM) to carry out precession electron diffraction (PED). In ordinary electron diffraction the beam hits the crystal at a fixed angle, often producing complex patterns because of dynamic scattering. PED solves that by rotating the beam in a conical sweep, recording a more complete diffraction pattern over dozens of orientations. The result is higher-quality diffraction data that can be turned into strain maps.

The workflow starts with ultra‑thin lamellae—cross‑sections of a chip that are roughly 80 nm thick— prepared using focused ion beam (FIB) milling.

Once the specimen is ready, it is inserted into a TEM microscope equipped with a PED module. Scanning diffraction allows the lab to measure the lattice parameters of the crystal with high spatial resolution in different regions of a device.

The technique delivers strain maps with 1 nm spatial resolution and ~ 0.02 percent precision, which places CEA-Leti among the world's leaders in nanoscale metrology.

The technique has been simplified and accelerated where possible to enable higher throughput and make better use of the instruments. The result is a faster turnaround time for characterization requests.

Three TEMs are now equipped to perform PED measurements, allowing CEA-Leti to handle a larger volume of samples and making the service accessible to more qualified microscopists.

The project didn't happen in isolation. Nicolas emphasizes the combined expertise of the team members that made it possible:

That partnership between fundamental research and application‑driven engineering helped turn an experimental methodology into a practical, routine characterization service. ​