In processes for coating objects, such as semiconductor wafers, with a film
of metal, such as titanium metal, a metal-containing compound, such as
TiCl.sub.4, is injected into a chamber containing the object and a portion
of the metal-containing compound reacts to provide the film of metal on
the object and a gas containing by-products, such as unreacted TiCl.sub.4
and TiCl.sub.x (x<4), which is discharged out of the chamber and passed
through a trap mechanism and an eliminator for the removal of the
by-products out of the gas. The by-products have relatively high vapor
pressures, making them difficult to trap. The Applicants have found that
by adding a reagent, such as water, O.sub.2 or NH.sub.3, into the exhaust
gas at a location upstream of the trap mechanism and eliminator, the
reagent reacts with the by-product in the gas to produce a compound, such
as TiCl.sub.4.2NH.sub.3, which has a significantly lower vapor pressure
than the by-product and can be removed in the trap mechanism.
Nos processos para revestir objeta, como wafers de semicondutor, com uma película do metal, tal como o metal titanium, de um composto metal-contendo, tal como TiCl.sub.4, é injetado em uma câmara que contem o objeto e uma parcela do composto metal-contendo reage para fornecer a película do metal no objeto e um gás que contem by-products, tais como TiCl.sub.4 e TiCl.sub.x unreacted (x
