Non Evaporable Getter (NEG) coating
SAES Getters is the industrial player with the largest experience in NEG coating technology (more than 15 years) and the widest records of ﬁnal users (more than 20). The coating facility covers a 120 m2 area which is temperature and humidity controlled. Within the same area a ISO 5 clean room is located which is used for assembling operations.
The facility is equipped with several NEG coating systems and with a transmission factor UHV testing bench for NEG coating chambers characterization. NEG coating of chambers as long as 6,2 m with gaps as small as 7 mm have been successfully accomplished. Mounting of the sputtering cathodes depends on the chamber section and geometry and can be optimized based on mathematical modeling. This allows achieving given speciﬁcations for the thickness distribution along the chamber proﬁle. An optimal trade oﬀ between pumping performances (NEG coating speed and capacity) and impedance properties can be worked out. Leveraging on SAES Getters expertise in NEG coating technology, SAES RIAL Vacuum can provide state of the art NEG coated chambers as a complete turn- key package.
It is of the outmost importance to be able to simulate and predict the pressure evolution in vacuum systems, as a function of pump distribution, outgassing surfaces and system geometry. SAES RIAL Vacuum can run calculations with well recognized programs in the scientiﬁc vacuum community, like MOLFLOW+, VASCO, LTspice, and also code developed internally, like SimulaTorr.
An example of the modeling of NEG coating distribution along the chamber section is showed in the pictures for the given chamber proﬁle.
Non Evaporable Getter (NEG) coating.
In this case the physical model included three sputtering cathode wires for the sputtering sources.
Coating thickness and chemical composition after the deposition process can be certiﬁed by means of experimental measures on silicon coupons representative of the sputtering process.
Silicon coupons are inserted in extension nipples attached to the chamber and exposed to the same coating process.