Debris mitigation in laser produced plasmas using three-dimensional manipulation of magnetic topology [PPPL M-1003]

Web Published:

­Debris Mitigation in Laser Produced Plasmas Using Three-Dimensional Manipulation of Magnetic Topology

Princeton Docket # 20-3704

Moore's law dictates that computer chips become ever smaller. The devices that fabricate these chips are facing constraints governed by fundamental physics. In order to achieve small chip size, the next generation of photolithography devices uses extreme ultraviolet (EUV) in order to produce smaller components. EUV is generated using laser produced plasma consisting of vaporizing tin droplets thousands of times a second with high powered lasers. This method can generate large amounts of high energy light, but the resulting debris eventually coats critical components inside the machine. This is especially detrimental to the delicate mirror which loses its reflectivity after a given number of shots. 


Charged debris particles moving through a magnetic field will be deflected from their original path, and careful configurations of magnetic fields can thus alter these trajectories and steer the particles away from the sensitive components. Disclosed is a method of debris mitigation in laser produced plasma EUV light sources. The method describes a class of magnetic field configurations which exhausts debris away from sensitive components of the EUV device. This class contains a large range of configurations that may be suited and tuned to specific application requirements with a high degree of flexibility and can be generated by coils that are located away from the light collection cone. 


  • Redirects ionized debris away from sensitive components in systems using laser produced plasma (LPP) for extreme ultraviolet (EUV) lithography in the chip industry



  • Streamlines chip production process by minimizing maintenance downtime and increasing operational lifetime
  • Current backfill gas strategy for debris mitigation absorbs EUV
  • Increases total EUV fluency



Ahmed Diallo is the deputy director for the Innovation Network for Fusion Energy (INFUSE), a distinguished research fellow, and a principal  research physicist at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL), where he serves as the leader of the pedestal control group for the National Spherical Torus Experiment-Upgrade (NSTX-U). Diallo specializes in laser-aided plasma diagnostics and is the recipient of a 2013 Early Career Research Program grant from the DOE’s Office of Science. Diallo has expanded his research portfolio to investigate the source physics for EUV lithography. 


Diallo earned a Ph.D. in physics from the University of Iowa after receiving a bachelor’s degree from the University of Montana and a DEUG A diploma from the University of Ouagadougou in Burkina-Faso. He was a postdoctoral fellow at the École Polytechnique Fédérale de Lausanne in Switzerland and a research fellow at the Australian National University (ANU).


Intellectual Property Status


Patent protection is pending.

Princeton is currently seeking commercial partners for the further development and commercialization of this opportunity. 



Chris Wright

Princeton University Office of Technology Licensing • (609) 258-6762•


Laurie Bagley

Princeton Plasma Physics Laboratory • (732) 991-7811 •


Patent Information:
For Information, Contact:
Chris Wright
Licensing Associate
Princeton University
Ahmed Diallo
Christopher Smiet
Ben Israeli
Marien Simeni Simeni