Master’s Thesis: Phase-Contrast X-ray Imaging of Advanced Semiconductor Packages

Do you want to help reveal what conventional X-ray imaging cannot see? Excillum develops the world’s brightest laboratory X-ray sources, and we are looking for a master’s student in physics, electrical engineering, applied mathematics or a similar field who is excited about X-ray phase-contrast imaging, advanced semiconductor packaging and experimentation.

About Excillum
At Excillum, we push the boundaries of X-ray technology to enable breakthroughs in manufacturing, medicine and science. Our advanced X-ray sources enhance the manufacturing of semiconductors, batteries, electronics and aerospace components, as well as enable new biomedical and material sciences. They make our customers’ X-ray systems faster and better with lower cost of operation.

Founded in 2007 by researchers from KTH, Excillum has grown into a global leader in advanced microfocus and nanofocus X-ray sources. Today, our products are used by leading industrial companies, instrument manufacturers and research institutions around the world.

About the project
X-ray phase-contrast imaging can improve the visibility of low-density features that produce weak absorption contrast. Used in fields such as medical soft-tissue imaging and materials science, it exploits phase shifts caused by the refractive index of different materials in the sample, complementing conventional absorption-based contrast.

Advanced packaging is a key technique improving the performance of modern electronic components. Next-generation high-end chips incorporate co-packaged optics, silicon photonics and waveguides for data transmission, as well as glass substrates. Thermal-interface materials are another important type of low-density feature in advanced packages. Non-destructive inspection of these structures remains challenging, and high-resolution phase-contrast imaging may offer a solution. However, metal layers and interconnects can strongly attenuate the low-energy X-rays required for phase contrast, creating a trade-off between sensitivity to low-density features and penetration through the package.

This thesis will evaluate the feasibility of using 3D X-ray phase-contrast imaging with nano-CT and/or laminography to inspect low-density structures in advanced electronic packages. Simulations will first assess feasibility and optimise our in-house imaging system. The most promising conditions will then be tested in a proof-of-concept experiment, with the possibility to perform further measurements if time permits.

What you will do

- Review the benefits and limitations of different X-ray phase-contrast imaging methods
- Simulate representative phase-contrast imaging use cases for electronic packages using our in-house simulation software
- Optimise key imaging parameters, including the X-ray spectrum, detector and scan geometry
- Validate the selected conditions experimentally
- If time permits, compare different target materials
- If time permits, evaluate different detectors

What you will learn

- X-ray imaging and CT
- Phase contrast imaging
- Image simulation
- Practical work with advanced laboratory instruments

Who you are

You are a master’s student in physics, electrical engineering, applied mathematics or a similar field, with a genuine interest in X-ray physics and simulation. You enjoy turning physics into models, and models into tools that others can use. To succeed in this project, we believe you have:

- Programming skills in Python
- Basic knowledge of X-ray physics and imaging
- Good communication skills in English

It is a strong merit if you have knowledge of X-ray imaging, CT, phase contrast or image simulation.

Practical information

- Level: Master’s thesis, 30 credits
- Start: Early 2027
- Location: Excillum, Jan Stenbecks torg 17, Kista – at least 50% on-site
- Working language: English
- Supervisors: Jenny Romell & Till Dreier
- Project owner: Till Dreier
- Compensation: SEK 15,000 halfway through the project and an additional SEK 15,000 upon successful completion. Excillum also covers project-related expenses such as travel and materials.

Apply
To apply, please submit your CV, a cover letter and a copy of your academic transcripts.
We look forward to your application! If you have any questions regarding the thesis, do not hesitate to contact Hugo Högberg West at [email protected] .