Thesis: DUV-Assisted Athermal Laser Grooving of Low-κ Dielectrics for Advanced Packaging

In cooperation with the Chair of Laser Technology (LLT), the Fraunhofer Institute for Laser Technology (ILT)—Europe’s leading center for contract research and development in the field of laser technology—is offering the opportunity to write a thesis on the topic: »DUV-Assisted Athermal Laser Grooving of Low-κ Dielectrics for Advanced Packaging«.

In advanced microelectronic packaging, low-κ dielectrics (e.g. nanoporous SiCO:H) are structured by laser grooving to reduce mechanical stress during chip dicing. State-of-the-art UV ultrashort pulsed lasers at 343 nm operate with high pulse overlap, causing cumulative heating, melt formation in the silicon substrate, delamination, and burr—critical defects when substrates are thinned below 50 µm. The fundamental problem: low-κ materials are largely transparent, so laser energy penetrates through the stack and is absorbed in the substrate rather than the target layer. This thesis explores a novel dual-pulse approach: a femtosecond DUV pulse (257 nm) transiently generates free carriers in a thin near-surface zone of the low-κ material, making it absorbing for a subsequent 515 nm fs-pulse. This enables controlled, substrate-preserving, athermal layer removal—confining energy deposition exactly where it is needed.

Be part of change

• You will review literature on laser–material interaction in nanoporous low-κ dielectrics

• Afterwards, you will set up and align the the dual-pulse optical arrangement (DUV pump + 515 nm ablation pulse)

• You will also be responsible for the pump-probe characterisation of transient optical properties after DUV excitation

• Through experiments, you will investigate the dual-pulse ablation in low-κ/Si layer systems

• The objectives of the project will be tailored to your skills and preferences

What you contribute

• You are studying Mechanical Engineering, Mechatronics, or a comparable programme

• You are interested in application-oriented research at the intersection of photonics and semiconductor manufacturing

• You work organised, structured, and independently

What we offer

• Team spirit: Creative, interdisciplinary environment with a motivated team, flat hierarchies, and an informal culture.

• Workplace: Excellent range of machines and equipment, as well as first-class office facilities.

• Involvement: Practice-oriented thesis in an innovative applied research environment.

• Work-life balance: Benefit from flexible working hours based on trust.

• Getting there: Good transport connections, parking spaces directly in front of the institute, an e-charging station, and a parking garage.

The position is limited in duration until completion of the thesis. We value and promote the diversity of our employees' skills and therefore welcome all applications – regardless of age, gender, nationality, ethnic and social origin, religion, ideology, disability, sexual orientation and identity. Severely disabled persons are given preference in the event of equal suitability. Our tasks are diverse and adaptable – for applicants with disabilities, we work together to find solutions that best promote their abilities.

With its focus on developing key technologies that are vital for the future and enabling the commercial utilization of this work by business and industry, Fraunhofer plays a central role in the innovation process. As a pioneer and catalyst for groundbreaking developments and scientific excellence, Fraunhofer helps shape society now and in the future.

Ready for a change? Then apply now and make a difference! Once we have received your online application, you will receive an automatic confirmation of receipt. We will then get back to you as soon as possible and let you know what happens next.

If you have any questions about this position, please contact:

Sönke Vogel, M.Sc. Phone: +49 241 8906-180

Fraunhofer Institute for Laser Technology ILT

www.ilt.fraunhofer.de

Requisition Number: 84906 Application Deadline: 10/31/2026