Abstract: A method for assessing alterations in the dielectric properties of insulating layers on a wafer of semiconductor material induced by plasma treatments. The method includes forming cells of EEPROM type on a wafer with source, drain and control gate surface terminals (pads), subjecting the cells to UV radiation so as to erase them thereby fixing a reference threshold voltage, applying programming voltages of preset value to at least one of the cells and measuring the corresponding threshold voltages, and subjecting this cell to UV radiation so as to restore its threshold to the reference value. The wafer is then subjected to the plasma treatment to be assessed, and the threshold voltages of the cells are measured and compared with the reference threshold voltage so as to derive from the comparison information on the alterations induced on the dielectrics formed on the wafer and on the distribution of the plasma potential.