Simple calibrated gas feed system.
Constant calibrated gas flow is needed in vacuum processes such as plasma etching and sputtering. It is shown that capillary tubes combined with a simple pressure regulator can give satisfactory results. Typical calibrations for different capillary lengths, diameters, and for different gas types (A, N(2), H(2), He, CH(4), CCl(2)F(2), CHClF(2)) are given. Agreement with viscous flow theory is good, and over a 100:1 range in flowrate the resettability and variability in flowrate varies from +/-2% to +/-20%.
Horwitz
C M
CM
School of Physics, University of Sydney, N. S. W. 2006 Australia.