Use of laser reflectometry for end-point detection during the etching of magnetic thin films

Abstract

Laser reflectometry at a wavelength of 679 nm has been employed for monitoring and detection of the end point during the etching of thin films of magnetic materials. Oscillations in the detected reflected signal 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 to compare with the observed results. This technique allows the etching to be stopped after removal of the thin magnetic multilayer film to an accuracy of better than 5 nm in the cases cited.