PYROMETRIC SUBSTRATE-TEMPERATURE MEASUREMENT DURING PLASMA-ETCHING

For the plasma-chemical patterning of polymer layers and foils it is n ecessary to check the substrate temperature during the plasma-etching process. Pyrometry was chosen as the temperature measurement technique because, due to the non-contact principle of its operation, it is wel l applicable in vacuum equipment and the condition and quality of the substrates may vary within a wide range. Knowledge of the IR-optical p roperties of the substrates and of the whole measuring arrangement, ho wever, is a prerequisite for the application of pyrometry. Taking into account all radiation components reaching the detector of the pyromet er under plasma etching conditions, the detector signal in the case of an application was compared with that of the ideal measuring arrangem ent (on calibration of the device). From this the relation between the value displayed by the pyrometer and the true substrate temperature w as derived. The correctness of this procedure and of the equation for calculating the substrate temperature was experimentally proved. Furth er investigations were made to determine the influence of the plasma c onditions on the substrate temperature.