USE OF LASER REFLECTOMETRY FOR END-POINT DETECTION DURING THE ETCHINGOF MAGNETIC THIN-FILMS

Laser reflectometry at a wavelength of 679 nm has been employed for mo nitoring and detection of the end point during the etching of thin fil ms of magnetic materials. Oscillations in the detected reflected signa l due to the periodicity of multilayer structures for Pt/Co and Cu/Co with periods as small as 3 nm have been recorded. Known details of the structures have been used to model the normal incidence reflectance t o compare with the observed results. This technique allows the etching to be stopped after removal of the thin magnetic multilayer film to a n accuracy of better than 5 nm in the cases cited. (C) 1997 American V acuum Society.