PRODUCTION OF THIN FILM MAGNETIC HEAD

PURPOSE:To obtain a production method where overetching is difficult to occur, by using a conductive foundation film having a characteristic suitable for iron- nickel alloy plating. CONSTITUTION:The conductive foundation film is used which has a moderate conductivity and can be closely plated with an iron-nickel alloy and has a soft magnetic characteristic approximating that of the plating film, namely, has a low magnetic resistance, a high permeability, and a high saturation magnetization. Etching under a resist frame 4 does not progress as long as a conductive film 3 has a part exposed to the etching liquid during etching, and meanwhile, the etching speed of the plating film is higher than that of the conductive film 3. Consequently, etching of the plating film is terminated and a substrate is taken out from the etching liquid before an adhesive layer 2 consisting of titanium or chromium is exposed. Thus, overetching is avoided to form a pattern with a high precision.