In-situ downstream plasma cleaner can remove hydrocarbon contamination inside the EUV/E-beam lithography and inspection system. Reduce carbon build-up on multilayer mirrors and mask blank.
SEMI-KLEEN Sapphire downstream plasma cleaner
Contamination issue in EUV lithography
EUV lithography (EUVL) has been used for sub 7nm nodes. EUV photon energy is almost 100eV. At such high energy, EUV lithography suffers many similar contamination issues as electron beam systems. Multilayer mirrors (MLMs) must be used as imaging optics and mask blank for EUVL. However, 1nm carbon buildup can reduce EUV reflectivity on a single surface by more than 1.4%. Since the EUV optics consists of many multilayer mirrors, the total reduction of the EUV light intensity due to contamination buildup can be significant. Hydrocarbon and other sources of contamination have been one of the major challenges for EUV lithography.
E-Beam lithography suffers from hydrocarbon contamination issue.
In electron beam lithography systems, even though primary electrons don’t touch any surface in electrostatic or magnetic lenses, hydrocarbon deposition can still occur on apertures or other areas where secondary electrons or backscattering electrons can land on. Carbon contamination along the optics column can also create serious charging issues. System resolution will degrade day by day due to charging-induced optical aberrations. Charging may also result in beam position drift issues. Carbon contamination build-up on the so-called pattern generator in maskless lithography can reduce its contrast.
Contamination in vacuum system can be cleaned by in-situ plasma cleaners
Unlike traditional lithography systems, next-generation lithography needs to work under a vacuum. The traditional gas-blow contamination control methods won’t work for the next-generation lithography systems. Polymer resists outgassing in the vacuum environment is a big source of hydrocarbon contaminants. All these factors make contamination control extremely challenging for the EUV and E-beam lithography and imaging equipment.
SEMI-KLEEN series plasma cleaner is specially designed to work on semiconductor capital equipment. SEMI-KLEEN Sapphire plasma source uses a sapphire crystal tube to build the plasma source and offer pristine cleanliness for the semiconductor capital equipment. The dielectric plasma tube inside the SEMI-KLEEN UHV plasma source is brazed to the metal flanges. No polymer sealings are used inside the SEMI-KLEEN UHV plasma source. All the sealing surfaces are metalized brazed joints or metal-metal contact. SEMI-KLEEN UHV in-situ plasma cleaner is directly compatible with UHV or XHV vacuum chamber. Special attention has been considered to the minimize the potential particle contamination issue from the gas delivery system, plasma chamber, and vacuum seal. We are working with leading research laboratories and industries to come up with a reliable contamination control solution for the EUV lithography system. Contact us today for more details.