Etchant for thin copper layers in integrated circuits - consists of aq. soln. of ammonium persulphate contg. sulphuric acid and hydrogen peroxide

摘要

The etchant pref. contains 20 g. (NH4)2SO4 in 100ml. aq. soln. + 1 ml. H2SO4 (95%) + 4 ml. H2O2 (30%). This soln. provides a suitable edge profile for the subsequent application of the insulating layer. The line structure obtd. by the use of a mask and the etching soln. is given, edges of which the angle is is approx. = 15 degrees in Cu layers of >0.1 mu thickness. Method gives an etch pattern of which the angle of the edges is low and the etching soln. does not attack the underlying metal and oxide layer. For the prodn. of intergrated circuits, and thin film magnetic field sensors.