Invited Paper VT-TuM5
Particle Behavior in Vacuum Systems: Protection Schemes for EUVL Critical Surfaces, Speed Controlled Particle Injection, Prevention of Particle Formation during Pump Down

Tuesday, October 20, 2015, 9:20 am, Room 230B

Extreme Ultraviolet Lithography (EUVL) is a leading lithography technology for the next generation semiconductor chips. Photomasks, in a mask carrier or inside a vacuum scanner, need to be protected from nanoparticle contamination down to below 20 nm diameter, the minimum feature size expected from this technology. We have developed models and performed experiments in vacuum tools down to 20 mTorr. Nanoparticles between 60 nm and 250 nm were injected into the vacuum chamber with controlled speed and concentration to validate the analytical and numerical models. Also, methods and models were developed to evaluate nanoparticle generation, transport and deposition on photomasks in carriers. Various protection schemes have been developed and evaluated using these experimental and modeling tools. Inside the vacuum chamber, nanoparticles could be formed during rapid vacuum pump down and/or by conversion of outgassing materials by soft x-ray. The detection and control of these nanoparticle contaminants will also be addressed in this presentation.