METHOD AND APPARATUS FOR PROCESS CONTROL OF MATERIAL EMITTING RADIATION

摘要

An apparatus for controlling a process, in which a control system is structured by having a direct desired value (for example the film thickness d) as the control target, with an emissivity power ratio Ku * (¢the .lambda. i power of .epsilon. 1!/¢the .lambda. j power of .epsilon. 2!) used as an indirect desired value, and a measured value of emissivity power ratio Ku obtainable from detection signals (Si (S1, S2, ...) of a radiation sensor (160) used as an indirect controlled variable. A process manipulated variable (170) is automatically controlled in accordance with the direct desired value (actual film thickness) such that the indirect controlled variable attains an indirect desired value as target. Thus, the controlling effect of the control apparatus is improved by the use of the excellent control parameter.