New leak element using 1D nanofluidic channels and indium sealing

Nanofluidic channels with a depth of ∼100 nm were developed as a leak element, where the fluidic channels were etched on silicon wafer by reactive ion etching and then enclosed by direct silicon bonding. Instead of the Torr-seal gluing method, a tight lamination between the chip and the vacuum flange was achieved using indium gasket sealing, eliminating the influence of Torr-seal outgassing. Two leak elements with different amount of parallel channels were fabricated and their values were characterized by the difference method. The results demonstrate that the conductance of the leak elements behave in reasonable agreement with their theoretically calculated conductance with relative errors of approximately 4.9% and 42.7%, respectively. The gas flow through these leak elements realizes molecular flow at pressures ranging from high vacuum up to 105 Pa for helium, argon, and nitrogen and can therefore be used as predictable leak elements for any gas.