An ultralow stress Ta4B absorber for x-ray masks

The stress controllability, stress uniformity, stress stability and dry etching characteristics of Ta4B films deposited by an in-line type sputtering system were investigated in detail. Low average stress Ta4B films within +/-10 MPa have been fabricated on polished SIC films that demonstrate excellent reproducibility by step annealing. Stress uniformity of the film showed an approximate range of 7 MPa on a Si wafer in a 30 mm square area when the deposition conditions were modified. The Ta4B him demonstrated long-term stress stability and excellent resistance to the acid and water used in the cleaning process. The Ta4B film also ensures fine pattern formations below 0.2 mu m.