Amorphous stuctured Ta4B absorber on SiC membrane for x-ray mask

Stress controllability, stress distribution and radiation stability of Ta4B absorber film on SiC membrane were investigated in detail. A low stress Ta4B film was deposited on as-deposited SiC membrane with excellent reproducibility by an rf magnetron sputtering using Ar gas. Ta4B film with very low stress below 10 MPa and high thermal stability have been obtained by annealing. The film has amorphous structure and uniform stress distribution of +/- 2.5 MPa in a window area of 28 mm square. The Ta4B film has been found to show high durability against SR irradiation. SR-induced displacement (3(sigma) ) of 0.8-micrometers -thick Ta4B film on SiC membrane were X equals 29 and Y equals 24 nm after irradiation of 531 kJ/cm2, which were within the measurement error of 30 nm.