P. Rudent et al., DESIGN OF A NEW SENSOR FOR MASS-FLOW CONTROLLER USING THIN-FILM TECHNOLOGY-BASED ON AN ANALYTICAL THERMAL-MODEL, Journal of vacuum science & technology. A. Vacuum, surfaces, and films, 16(6), 1998, pp. 3559-3563
Citations number
8
Categorie Soggetti
Physics, Applied","Materials Science, Coatings & Films
Thermal mass flow controllers are widely used in the semiconductor ind
ustry to deliver accurate process gas compositions and concentrations
to the processing chamber. The sensor, a stainless-steel capillary tub
e, is the most critical part of the mass flow controller. We have desi
gned a new sensor using thin-him technology in order to improve its re
liability and to decrease its response time. The two temperature senso
rs are deposited platinum on an electrical insulating layer directly u
pon the capillary tube (without exposure to the gas stream) whereas th
e sensor is constantly heated by a resistive wire. The so-obtained sen
sors are very promising and the new design and technology could give u
s improvements which the old design and technology (two resistive coil
s) would not have been able to give us. The physical mechanisms of thi
s new sensor are described by a third-order steady-state analytical th
ermal model which gives good results when compared with experiments. T
his fundamental study also includes the evolution of the correction fa
ctors as a function of the flow. We present here the thermal model, th
e new structure of the sensor, and its advantages. (C) 1998 American V
acuum Society. [S0734-2101(98)02306-9].