NOVELTY - Controlling vapor deposition rate and composition involves measuring vapor flux rate of vapor being fed from vapor source and deposited; calculating deposition rate based on measured vapor flux rate, where correlation function between flux rate and deposition rate is used to calculate deposition rate; and controlling deposition rate by feedback control loop based on deposition rate.    USE - As multi-level control schemes for controlling vapor deposition rate and composition, particularly as evaporation rate control system, widely used in microfabrication, and to make macro-scale products such as solar cell or metalized plastic film.    ADVANTAGE - The control scheme is capable of detecting and reacting to fluctuations in the process condition to compensate for variations in the flux to deposition rate relationship, achieved via control loop approach. The system provides the integrated signals from sensors which allows direct access to material consumption/mass loss of source, thus it can be used to control feedstock replenishment mechanism controlling source to a fixed fill level. It also controls vapor source power to a fixed evaporation level. The vapor deposition control system can control deposition rate of in-line, multi-stage deposition system capable of continuous processing of moving substrates.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for vapor deposition rate control system comprising vapor flux monitor capable of measuring vapor flux rate of vapor being deposited; vapor flux control module capable of reading flux monitor and controlling vapor flux rate by adjusting vapor source feed rate from vapor source; and feedback control loop based on correlation function between flux rate and deposition rate of vapor being deposited, to correlate flux rate to deposition rate and control deposition rate by control module.    DESCRIPTION OF DRAWING(S) - The figure shows schematic diagram of one-stage multilevel thermal evaporation deposition control system.