Thin, strong bond for vacuum seal

 

Thu, 12/04/2014 - 10:09am Patrick Egan, NIST Silicate bonds are so thin they are transparent. Image: NISTAn ultra-stable, ultra-thin bonding technology has been adapted by researchers in NIST Physical Measurement Laboratory (PML)’s Semiconductor and Dimensional Metrology Div. for use as a super-strong vacuum seal. Though it is less than 100 nm thick, the bond can withstand pressure up to 2 megapascals (almost 300 pounds per square inch), and its drift, or how much it shifts over time, is on the order of less than 3 trillionths of a meter per hour. In tests with helium, the bonds show leak rates of less than 10-8 standard cubic centimeters per meter, a performance as good as that of an o-ring seal. The method, called silicate bonding, had previously been used by other experiments to affix optical materials to one another but its use as a vacuum seal had not been attempted to the researchers’ knowledge. The team used the technique for their recent prototype of the first photonic pressure sensor, a device that outperformed the present standard, a 3-m-tall mercury-based device, in resolution, speed, and range at a fraction of the size. Several industry representatives have already shown interest in the prototype pressure sensor, which could be used for semiconductor, glass, and aerospace manufacturing. Source: NIST