D.C. reactively sputtered iron oxide films for selectively semitransparent photomasks II: Relation between the structure of the films and their mechanical and chemical properties

The influence of the oxygen content in an Ar-O 2 gas flow on the wear resistance, the chemical solubility, the quality of the photolithographic image and the structure of d.c. reactively sputtered iron oxide films was investigated. It was found from X-ray analysis that the films are composed of α-Fe 2 O 3 with varying degrees of texture and crystallization. The films with the most texture are the most wear resistant; the films with the highest degree of crystallization possess the lowest chemical solubility. A critical value of the oxygen content was observed, under which the films contain a considerable concentration of suboxides which adversely affect the quality of the photolithographic image. Based on the investigation some conclusions are drawn about the optimum regimes for the deposition of semitransparent films for photomasks.