Patent ID: 6228420
Filing Date: 2001-05-08
Classification: C23C

Abstract:
A method to maintain a consistent film thickness deposited by chemical vapor deposition, which method is applicable to a chemical vapor deposition system wherein a reactant is delivered to a reaction chamber of the chemical vapor deposition system, and the chemical vapor deposition system comprises at least a reaction chamber, an ampule, a mass flow controller and a data management device, and the values for an initial mass flow rate of the reactant (m.sub.0), an initial volume occupied by a gas phase (V.sub.0) in the ampule, and an initial weight of the reactant (W.sub.0) in the ampule are preset in the data management device, the method comprising the steps of:obtaining an accumulated time (t) from the mass flow controller;conducting following calculations in the data management device:(a) V(t)=V.sub.0 +4.57.times.10.sup.-4 t, wherein V(t) is a volume of the gas phase in the ampule at time t;(b) m(t)=m.sub.0.times.(0.414+0.217.times.e.sup.(V0/V(t))), wherein m(t) is a mass flow rate of the reactant at time t;(c) K=m.sub.0 /m(t), wherein K is a compensative coefficient;multiplying an initial deposition time by K to obtain an actual deposition time; and;conducting chemical vapor depositing for duration of the actual deposition time.